U.S. patent application number 11/052418 was filed with the patent office on 2005-07-07 for information reproduction apparatus, information carrier, and information recording apparatus.
Invention is credited to Ishibashi, Hiromichi, Kimura, Naohiro, Watanabe, Katsuya.
Application Number | 20050147399 11/052418 |
Document ID | / |
Family ID | 15441422 |
Filed Date | 2005-07-07 |
United States Patent
Application |
20050147399 |
Kind Code |
A1 |
Kimura, Naohiro ; et
al. |
July 7, 2005 |
Information reproduction apparatus, information carrier, and
information recording apparatus
Abstract
An information reproduction apparatus of the present invention
comprises a rotating section 2 for rotating an information carrier
1 on which a unit of continuous information capable of being
continuously read out is recorded, a CLV control section 9 for
controlling the rotating section in such a manner that the
information carrier is rotated at a constant linear velocity, a CAV
control section 9 for controlling the rotating section in such a
manner that the information carrier is rotated at a constant
angular velocity, a rotation control selection 14 for selectively
operating the CLV or CAV control section, and an information
determination section 14 for detecting an information length of the
continuous information. The rotation control selection section is
constructed in such a manner as to selectively operate the CLV or
CAV control section based on a result of the detection of the
information length of the continuous information.
Inventors: |
Kimura, Naohiro; (Kyoto,
JP) ; Watanabe, Katsuya; (Nara, JP) ;
Ishibashi, Hiromichi; (Osaka, JP) |
Correspondence
Address: |
MARK D. SARALINO (GENERAL)
RENNER, OTTO, BOISELLE & SKLAR, LLP
1621 EUCLID AVENUE, NINETEENTH FLOOR
CLEVELAND
OH
44115-2191
US
|
Family ID: |
15441422 |
Appl. No.: |
11/052418 |
Filed: |
February 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11052418 |
Feb 7, 2005 |
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09979577 |
Nov 19, 2001 |
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6870802 |
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09979577 |
Nov 19, 2001 |
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PCT/JP00/03430 |
May 26, 2000 |
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Current U.S.
Class: |
386/222 |
Current CPC
Class: |
G11B 19/28 20130101;
G11B 19/12 20130101 |
Class at
Publication: |
386/125 ;
386/126 |
International
Class: |
H04N 005/781 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 1999 |
JP |
11/147936 |
Claims
1. An information reproduction apparatus comprising: a rotating
section for rotating a disk-like information carrier on which
moving image information is recorded; a CAV control section for
controlling the rotating section in such a manner that the
information carrier is rotated at a constant angular velocity; a
reproduced signal processing section for reading out the moving
image information from the information carrier and processing the
moving image information; and an information determination section
for determining whether or not a type of information to be
reproduced is moving image information, wherein when the
information determination section determines that the type of
information to be reproduced is moving image information, the CAV
control section controls the rotating section in such a manner that
the information carrier is rotated at as low a number of
revolutions as a level where a transfer rate required to reproduce
information recorded in a most inner circumstance can be
secured.
2. An information reproduction apparatus according to claim 1,
wherein the information determination section determines that the
information to be reproduced is moving image information, when it
is detected that an information length of information to be
reproduced is greater than or equal to about 1 GB.
3. An information reproduction apparatus according to claim 1,
wherein the information determination section determines that the
information to be reproduced is moving image information, when a
command specialized in reading of moving image information is
input.
4. An information reproduction apparatus according to claim 1,
wherein the information determination section determines that the
information to be reproduced is moving image information, when it
is verified that a regional code is recorded in the information
carrier.
5. An information reproduction apparatus according to claim 1,
wherein the information determination section determines that the
information to be reproduced is moving image information, when it
is verified that defect management information is not registered in
the information carrier.
6. An information reproduction apparatus according to claim 1,
wherein the information determination section determines that the
information to be reproduced is moving image information, when it
is verified that an extension of information to be reproduced
indicates a MPEG or VOB file.
7. An information reproduction apparatus according to claim 1,
wherein the information determination section determines that the
information to be reproduced is moving image information, when it
is verified that information to be reproduced is restrained under a
parental lock.
8. An information reproduction apparatus according to claim 1,
wherein the information determination section determines that the
information to be reproduced is moving image information, when it
is verified that authentication has been conducted so as to protect
copyright.
9. An information reproduction apparatus according to claim 1,
further comprising: a focusing section for focusing a light beam to
the information carrier; a focusing control section for controlling
the light beam focused by the focusing section into a predetermined
focus state; a tracking control section for controlling the light
beam focused by the focusing section in such a manner that the
light beam correctly scans a track on the information carrier; and
a reproduced signal processing section for reproducing a signal
read out from the information carrier.
10. An information reproduction method comprising the steps of: (a)
rotating a disk-like information carrier on which moving image
information is recorded; (b) controlling the rotation of the
information carrier in such a manner that the information carrier
is rotated at a constant angular velocity; (c) reading out the
moving image information from the information carrier and
processing the moving image information; and (d) determining
whether or not a type of information to be reproduced is moving
image information, wherein when it is determined in the step (d)
that the type of information to be reproduced is moving image
information, the rotation of the information carrier is controlled
in such a manner that the information carrier is rotated at as low
a number of revolutions as a level where a transfer rate required
to reproduce information recorded in a most inner circumstance can
be secured.
11. An information reproduction method according to claim 10,
wherein it is determined in the step (d) that the type of
information to be reproduced is moving image information, when it
is detected that an information length of information to be
reproduced is greater than or equal to about 1 GB.
12. An information reproduction method according to claim 10,
wherein it is determined in the step (d) that the type of
information to be reproduced is moving image information, when a
command specialized in reading of moving image information is
input.
13. An information reproduction method according to claim 10,
wherein it is determined in the step (d) that the type of
information to be reproduced is moving image information, when it
is verified that a regional code is recorded in the information
carrier.
14. An information reproduction method according to claim 10,
wherein it is determined in the step (d) that the type of
information to be reproduced is moving image information, when it
is verified that defect management information is not registered in
the information carrier.
15. An information reproduction method according to claim 10,
wherein it is determined in the step (d) that the type of
information to be reproduced is moving image information, when it
is verified that an extension of information to be reproduced
indicates a MPEG or VOB file.
16. An information reproduction method according to claim 10,
wherein it is determined in the step (d) that the type of
information to be reproduced is moving image information, when it
is verified that information to be reproduced is restrained under a
parental lock.
17. An information reproduction method according to claim 10,
wherein it is determined in the step (d) that the type of
information to be reproduced is moving image information, when it
is verified that authentication has been conducted so as to protect
copyright.
18. An information reproduction method according to claim 10,
further comprising: (e) focusing a light beam to the information
carrier; (f) controlling the light beam focused in the step (e)
into a predetermined focus state; (g) controlling the light beam
focused in the step (e) in such a manner that the light beam
correctly scans a track on the information carrier; and (h)
reproducing a signal read out from the information carrier.
Description
TECHNICAL FIELD
[0001] The present invention relates to an information reproduction
apparatus for reproducing information recorded on a disk-like
information carrier, the disk-like information carrier, and an
information recording apparatus for recording information on the
information carrier.
BACKGROUND ART
[0002] CDs (Compact Disk) and DVDs (Digital Versatile Disk) have
respective unified physical format standards in which information
is recorded into prepits at a linear velocity of 1.3 m/s for CDs
and at a linear velocity of 3.49 m/s for DVDs regardless of whether
the information is audio/video information or code information.
[0003] For apparatuses (CD players and DVD players) for reproducing
audio/video information thus recorded on a disk at a constant
linear velocity, conventionally, access performance is not
considered to be important, and CLV (Constant Linear Velocity)
control is performed in order to secure a low level of noise and
vibration. In CLV control, the number of revolutions of a spindle
motor is controlled in such a manner that a transfer rate (or
linear velocity) is constant over a disk range from an inner
circumference to an outer circumference of the disk. Such control
is achieved as follow. The phase of the frequency of a reproduction
clock in a PLL (Phase-Locked Loop) control section of a signal
processing circuit is synchronized with the phase of the frequency
of a reference clock obtained by frequency-dividing a quartz
oscillator, and the frequency of the reproduction clock is
controlled using the frequency of the frequency-divided reference
clock, thereby generating a control signal for the spindle
motor.
[0004] For apparatuses for reproducing a disk in which computer
code information is recorded (a CD-ROM [Read-Only Memory] drive and
a DVD-ROM drive), jitter-free for controlling the reproduction
clock frequency per se of the PLL of the signal processing circuit
is introduced, and CAV (Constant Angular Velocity) control is
performed to obtain satisfactory fast-speed access performance. In
CAV control, a spindle motor is controlled in such a manner that
the number of revolutions is constant over a disk range from an
inner circumference to an outer circumference of the disk.
[0005] Recently, hybrid disks which are CDs, DVDs, or the like in
which audio or video information and computer code information are
mixed have been produced. For such disks, conventionally, there is
not a definition, a regulation, nor a proposal as to the order of
pieces of information to be recorded, and a disk site at which
information about the size of a unit of information will be
recorded on the disk. For example, a considerably large size of
code information may be recorded after a considerably short-time of
music. Conversely, a considerably small size of code information
may be recorded after a considerably long-time of music.
[0006] For such a disk, in the conventional art, audio/video
information and code information are all reproduced by either a CLV
control method or a CAV control method. Specifically, all
information on the disk is subjected to data processing for
audio/video information using CLV control where a transfer rate is
reduced all over the disk. Alternatively, all information on the
disk is subjected to data processing for code information
(specifically, information, such as audio, is also temporarily
stored in a cache memory or the like and thereafter transferred as
memory information to the outside) using CAV control where a
transfer rate is increased toward the outer circumference of the
disk.
[0007] In the case where all information on a disk is reproduced
using CLV control, code information is reproduced using CLV control
even if code information is predominantly recorded on the disk. In
such a case, even when code information is randomly accessed from
an application on a host computer, the response time of a spindle
motor predominantly occupies the access time, resulting in a
significant reduction in access speed. Further, the noise caused by
driving the motor in the access causes problems.
[0008] In the case where all information on a disk is reproduced
using CAV control, random access seldom occurs since audio/video
information is predominantly recorded. Although a host computer
exhibits almost the same performance in outputting audio or
displaying moving images if a transfer rate is greater than or
equal to a predetermined value, a spindle motor is rotated at a
higher speed greater than or equal to a required value, so that
rotation, or vibration due to mass eccentricity or the like causes
noise.
[0009] For a kind of CD (CD-EX (Extra) or the like), a reproduction
apparatus capable of switching between CLV and CAV control is
available, in which music information is subjected to CLV control,
while code information, such as data relating to lyrics or songs,
or artist information, is subjected to CAV control. Such a
reproduction apparatus distinguishes audio information from code
information using disk information recorded in a lead-in area, a
TOC (Table Of Contents) area, and the like, or a sub-code defined
in a logical format. Based on this identification, CAV control and
CLV control are switched.
[0010] In the above-described technique in which CLV control and
the CAV control are switched, when a disk is sequentially read from
an inner circumference toward an outer circumference, a switching
operation between CLV control and CAV control occurs every time the
type of information is changed, resulting in a reduction in an
average reproduction rate. Further, noise or heat is generated in a
spindle motor in the switching.
[0011] The present invention is provided to solve the
above-described problems. The object of the present invention is to
provide: an information reproduction apparatus which appropriately
selects CLV or CAV control, depending on information to be
reproduced; an information carrier having an information recording
area for recording information suitable for reproduction using
CLV/CAV control; and an information recording apparatus for
recording information on the information carrier.
DISCLOSURE OF THE INVENTION
[0012] An information reproduction apparatus according to the
present invention comprises a rotating section for rotating a
disk-like information carrier on which a unit of continuous
information capable of being continuously read out is recorded, a
CLV control section for controlling the rotating section in such a
manner that the information carrier is rotated at a constant linear
velocity, a CAV control section for controlling the rotating
section in such a manner that the information carrier is rotated at
a constant angular velocity, a rotation control selection section
for selectively operating the CLV control section or the CAV
control section, and an information determination section for
detecting an information length of the continuous information. The
rotation control selection section is constructed in such a manner
as to selectively operate the CLV control section or the CAV
control section based on a result of the detection of the
information length of the continuous information by the information
determination section. Therefore, the above-described object can be
achieved.
[0013] In one embodiment of this invention, when first information
having the information length as detected by the information
determination section larger than a predetermined size is
reproduced, the CLV control section is operated, and when second
information having the information length as detected by the
information determination section smaller than the predetermined
size is reproduced, the CAV control section is operated.
[0014] In one embodiment of this invention, when first information
having the information length as detected by the information
determination section larger than a predetermined size is
reproduced, the CAV control section is controlled in such a manner
that the information carrier is rotated at as low a number of
revolutions as a level where a transfer rate required to reproduce
information recorded in a most inner circumstance of the disk-like
information carrier can be secured, and when second information
having the information length as detected by the information
determination section smaller than the predetermined size is
reproduced, the CAV control section is operated.
[0015] In one embodiment of this invention, the continuous
information includes a header portion recording a block size or a
file size, and a data portion, and the information determination
section is constructed in such a manner as to detect the
information length based on a content of the header portion.
[0016] In one embodiment of this invention, the information carrier
has a first information recording area at an inner circumference
side and a second information recording area at an outer
circumference side both arranged in a radial direction, and the
first information is recorded in the first information recording
area and the second information is recorded in the second
information recording area.
[0017] Another information reproduction apparatus according to the
present invention comprises a rotating section for rotating a
disk-like information carrier on which moving image information is
recorded, a CLV control section for controlling the rotating
section in such a manner that the information carrier is rotated at
a constant linear velocity, a CAV control section for controlling
the rotating section in such a manner that the information carrier
is rotated at a constant angular velocity, a rotation control
selection section for selectively operating the CLV control section
or the CAV control section, a reproduced signal processing section
for reading out the moving image information from the information
carrier and processing the moving image information, and an
information determination section for determining whether or not a
type of information to be reproduced is moving image information.
The rotation control selection section is constructed in such a
manner as to selectively operate the CLV control section or the CAV
control section based on a result of the determination by the
information determination section of whether or not information to
be reproduced is moving image information. Therefore, the
above-described objective can be achieved.
[0018] In one embodiment of this invention, when the information
determination section determines that the type of information to be
reproduced is moving image information, the CLV control section is
operated.
[0019] In one embodiment of this invention, when the information
determination section determines that the type of information to be
reproduced is moving image information, the CAV control section is
controlled in such a manner that the information carrier is rotated
at as low a number of revolutions as a level where a transfer rate
required to reproduce information recorded in a most inner
circumstance can be secured.
[0020] In one embodiment of this invention, the information
determination section is constructed in such a manner that when it
is detected that an information length of information to be
reproduced is greater than or equal to about 1 GB, the information
determination section determines that the information to be
reproduced is moving image information.
[0021] In one embodiment of this invention, the information
determination section is constructed in such a manner that when a
command specialized in reading of moving image information is
input, the information determination section determines that the
information to be reproduced is moving image information.
[0022] In one embodiment of this invention, the information
determination section is constructed in such a manner that when it
is verified that a regional code is recorded in the information
carrier, the information determination section determines that the
information to be reproduced is moving image information.
[0023] In one embodiment of this invention, the information
determination section is constructed in such a manner that when it
is verified that defect management information is not registered in
the information carrier, the information determination section
determines that the information to be reproduced is moving image
information.
[0024] In one embodiment of this invention, the information
determination section is constructed in such a manner that when it
is verified that an extension of information to be reproduced
indicates a MPEG or VOB file, the information determination section
determines that the information to be reproduced is moving image
information.
[0025] In one embodiment of this invention, the information
determination section is constructed in such a manner that when it
is verified that information to be reproduced is restrained under a
parental lock, the information determination section determines
that the information to be reproduced is moving image
information.
[0026] The information determination section is constructed in such
a manner that when it is verified that authentication has been
conducted so as to protect copyright, the information determination
section determines that the information to be reproduced is moving
image information.
[0027] The information reproduction apparatus further comprises a
focusing section for focusing a light beam to the information
carrier; a focusing control section for controlling the light beam
focused by the focusing section into a predetermined focus state; a
tracking control section for controlling the light beam focused by
the focusing section in such a manner that the light beam correctly
scans a track on the information carrier, and a reproduced signal
processing section for reproducing a signal read out from the
information carrier.
[0028] An information carrier according to the present invention is
a disk-like information carrier having a plurality of information
recording areas. The plurality of information recording areas are
separated along a radial direction of the information carrier, and
information is recorded in each of the plurality of information
recording area depending on the information length of a unit of
continuous information capable of being continuously read out.
[0029] Preferably, information having an information length of
continuous information larger than a predetermined size is recorded
in the information recording area at an inner circumference side of
the information carrier, and information having an information
length of continuous information smaller than the predetermined
size is recorded in the information recording area at an outer
circumference side of the information carrier.
[0030] More preferably, a specific area for recording the number of
the plurality of information recording areas, positional
information of each information recording area, and a minimum size
of continuous information recorded in each information recording
area is further provided.
[0031] An information recording apparatus according to the present
invention comprises a recording section for recording information
including a unit of continuous information capable of being
continuously recorded into a disk-like information carrier having a
plurality of information recording areas separated along a radial
direction of the information carrier. The information recording
apparatus further includes an information determination section for
detecting an information length of the continuous information, and
the recording section is constructed in such a manner that the
continuous information is recorded into the corresponding
information recording area depending on the information length
detected by the information determination section. Therefore, the
above-described object can be achieved.
[0032] Preferably, the recording section is controlled by the
information determination section in such a manner that information
having an information length of continuous information larger than
a predetermined size is recorded in the information recording area
at an inner circumference side of the information carrier, and
information having an information length of continuous information
smaller than the predetermined size is recorded in the information
recording area at an outer circumference side of the information
carrier.
[0033] More preferably, the recording section is constructed in
such a manner that the number of the plurality of information
recording areas, positional information of each information
recording area, and a minimum size of continuous information
recorded in each information recording area are recorded in a
specific area of the information carrier.
[0034] The information recording apparatus further comprises a
rotating section for rotating the information carrier at a
predetermined number of revolutions, a focusing section for
bringing and focusing a light beam to the information carrier, a
focusing control section for controlling the light beam focused by
the focusing section into a predetermined focus state, and a
tracking control section for controlling the light beam in such a
manner that the light beam correctly scans a track on the
information carrier.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 is a block diagram showing a configuration of an
information reproduction apparatus according to Embodiments 1 and 2
of the present invention.
[0036] FIG. 2 is a block diagram showing a detailed configuration
of a spindle control circuit in the information reproduction
apparatus of FIG. 1.
[0037] FIG. 3 is a schematic diagram showing a logical format of
information to be reproduced by the information reproduction
apparatus of Embodiment 1.
[0038] FIG. 4 is a schematic plan view showing a configuration of
an information carrier according to Embodiment 3 of the present
invention.
[0039] FIG. 5 is a schematic diagram showing a logical format of a
most inner circumference information portion of the information
carrier of FIG. 4.
[0040] FIG. 6 is a characteristic graph showing relationships
between a radial position, and the number of revolutions and a
transfer rate, of an information carrier of a first example of
Embodiment 3.
[0041] FIG. 7 is a characteristic graph showing relationships
between a radial position, and the number of revolutions and a
transfer rate, of an information carrier of a second example of
Embodiment 3.
[0042] FIG. 8 is a block diagram showing a configuration of an
information recording apparatus according to Embodiment 4 of the
present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0043] First, fundamental characteristic features of the present
invention will be described.
[0044] An information reproduction apparatus according to the
present invention determines the information length or information
type (whether or not the information is a moving image) of
continuous information and, based on a result of the determination,
performs reproduction using CAV control or CLV control. As used
herein, the term "continuous information" refers to a unit of
information which can be continuously read from an optical
disk.
[0045] The information length of continuous information is
determined by detecting data relating to the information length of
the information recorded in each header. When the information
length is greater than a predetermined size, CLV control, or CAV
control in which the number of revolutions is limited, is
performed. When the information length is less than the
predetermined size, CAV control is performed. The information type,
i.e., whether or not the information is a moving image, is
estimated based on data relating to copyright protection, a
regional code, code information for limiting reproduction, or the
like.
[0046] An information carrier (optical disk) according to the
present invention is a disk-like information carrier on which a
plurality of information recording areas are provided for recording
information, depending on the information length of continuous
information. These information recording areas are separated along
a radial direction of the information carrier. In the information
carrier of the present invention, preferably, information having
the information length of continuous information greater than a
predetermined size is recorded in an information recording area
provided at the inner circumference side of the information
carrier, while information having the information length of
continuous information less than the predetermined size is recorded
in an information recording area provided at the outer
circumference side of the information carrier.
[0047] Further, in the information recording apparatus of the
present invention, a recording section is provided for recording
information into a corresponding information recording area of the
information carrier based on the information length of continuous
information which is a unit of information capable of being
continuously read from an optical disk. Preferably, information
having the information length of continuous information greater
than a predetermined size is recorded in an information recording
area provided at the inner circumference side of the information
carrier, while information having the information length of
continuous information less than the predetermined size is recorded
in an information recording area provided at the outer
circumference side of the information carrier.
[0048] According to the present invention, rotational driving
control (CLV or CAV control) optimal to information is performed in
reproducing information, thereby reducing noise in reproducing
music or video information. Further, an average access time and an
average reproduction time for the entire information carrier can be
reduced.
[0049] Hereinafter, embodiments of the present invention will be
described with reference to the accompanying drawings.
Embodiment 1
[0050] An information reproduction apparatus and its reproduction
method according to Embodiment 1 of the present invention will be
described. FIG. 1 schematically shows a configuration of the
information reproduction apparatus of Embodiment 1.
[0051] Information recorded on a disk 1 is read out by an optical
pickup 3. More specifically, the optical pickup 3 correctly focuses
a light beam to a pit or a mark recorded on a track of the disk 1
by employing a focusing section provided therein, and reads a
signal based on the intensity of reflected light. The light beam is
shifted to a desired track on the disk 1 by a traverse motor 4
which moves the optical pickup 3 in a radial direction of the disk
1.
[0052] The light beam is brought into focus on a disk, and is used
to correctly scan a pit sequence (track), by a control circuit 8
which functions as follows. A focusing error signal and a tracking
error signal input from the optical pickup 3 are subjected to low
range compensation, phase compensation, and the like in the control
circuit 8, and the compensated signal is fed back via a focus
driving circuit 5 and a tracking drive circuit 6 to a focusing
actuator and a tracking actuator provided in the optical pickup 3.
Therefore, focusing servo control is performed in such a manner as
to bring a light beam to focus on a disk, and, tracking servo
control is performed in such a manner as to correctly scan a pit
sequence (track).
[0053] The optical pickup 3 creates an RF (Radio Frequency) signal.
The RF signal is converted to a binary signal by a data slicer 11.
The binary signal is input to a PLL (Phase-Locked Loop) circuit 12.
The PLL circuit 12 generates a reproduction clock frequency based
on the binary signal and synchronously extracts a signal on the
disk.
[0054] Rotation of the disk 1 is controlled by a spindle motor 2
(rotating section). In the present invention, such control of
rotation is CLV control and CAV control. A control signal required
for the spindle motor 2 to achieve CLV control or CAV control is
generated by a spindle control circuit 9 (a CLV control section and
a CAV control section). The spindle control circuit 9 generates a
control signal for the spindle motor 2 from the reproduction clock
frequency in the case of CLV control, and generates a control
signal for the spindle motor 2 from an FG (Frequency Generator)
signal obtained by a rotation detector of the spindle motor 2 in
the case of CAV control. With these control signals, the rotation
of the spindle motor 2 is controlled via a spindle drive circuit
10.
[0055] Hereinafter, the CAV control and the CLV control of the
spindle motor 2 and the switching therebetween will be described
with reference to FIGS. 1 and 2. FIG. 2 is a block diagram showing
a detailed internal configuration of the spindle control circuit 9
of FIG. 1.
[0056] First, the CLV control will be described. As described
above, a binary signal output from the data slicer 11 is input to
the PLL circuit 12. A reproduction clock frequency generated by the
PLL circuit 12 is input to the spindle control circuit 9. The
reproduction clock frequency input to the spindle control circuit 9
is converted by an S-P converter 102 from frequency information to
phase information. Further, a subtracter 106 is used in calculating
a phase error between the reproduction clock frequency and a
reference clock frequency obtained by frequency division of a
quartz oscillator. The resultant phase error is multiplied by a
predetermined gain by a multiplier 104 and the result is input to
an adder 107. By performing phase control in this manner, the
variation rate of rotation with respect to load torque in a control
region is theoretically zero, thereby making it possible to control
the rotation of the spindle motor 2 within a jitter margin.
[0057] However, the sole use of the phase control causes the drive
control system to be a second order system and therefore unstable.
Therefore, as described below, frequency control is performed so as
to produce a velocity control term which is in turn added to a
phase control term, there by stabilizing the drive control system.
Specifically, the reproduction clock frequency is frequency-divided
by a frequency divider 101 by a factor of N (where N is a natural
number), and a frequency error between the divided clock frequency
and the reference clock frequency is calculated via a subtracter
105, and multiplied by a predetermined gain by the multiplier 103,
and the result is input to the adder 107. Thus, the velocity
control term is added to the phase control term. A control signal
EC to which a frequency error and a phase error are added is output
via a switch 114 for switching CAV/CLV control to a spindle drive
circuit 10. In this manner, CLV rotation control is achieved.
[0058] Next, the CAV control will be described. Similar to as
described above, an FG signal generated by the rotation detector of
the spindle motor 2 is input to the control circuit 8, and is then
frequency-divided by a predetermined factor, and the result is
input to the spindle control circuit 9. The input FG signal is
converted by an S-P converter 109 from frequency information to
phase information. A phase error between the converted FG signal
and a reference FG signal corresponding to the constant number of
revolutions generated by the control circuit 8 is calculated via a
subtracter 112, and is multiplied by a predetermined gain by a
multiplier 110, and the result is input to an adder 113. By
performing phase control in this manner, the variation rate of
rotation with respect to load torque in a control region is
theoretically zero, thereby making it possible to control the
rotation of the spindle motor within a jitter margin.
[0059] However, the sole use of the phase control causes the drive
control system to be a second order system and therefore unstable.
Therefore, a frequency error between the divided FG signal and the
reference FG signal is calculated via a subtracter 111, and is
multiplied by a predetermined gain by a multiplier 108, and the
result is input to the adder 113 so as to perform frequency control
to produce a velocity control term which is in turn added to the
phase control term, thereby achieving stabilization. A control
signal EC to which a frequency error and a phase error are added is
output via the switch 114 for switching CAV/CLV control to a
spindle drive circuit 10. In this manner, CAV rotation control is
achieved.
[0060] Next, the switching between CAV control and CLV control will
be described with reference to FIG. 3 as well as FIGS. 1 and 2.
[0061] FIG. 3 schematically shows an exemplary format of one piece
of continuous information 30. To make it easier to switch between
CAV control and CLV control, the information 30 includes divided
portions, i.e., a header portion 37 and a data portion 38. Further,
the header portion 37 includes the following information: SYNC 31
for frame synchronization; ADRS 32 indicating the address of the
recorded information; SIZE 33 indicating the size of the
information (block size or file size); CONTENTS 34 indicating the
type of the information; and GAP 35 indicating a boundary between
the header portion 37 and the data portion 38. A reproduced signal
extracted by synchronizing with the generated reproduction clock
frequency in the PLL circuit 12 is subjected to error correction
and demodulation by a demodulation circuit 13 (see FIG. 1). The
size of the information to be reproduced (information length) is
determined and processed by a system controller 14 based on
information in the header portion 37 detected by the demodulation
circuit 13.
[0062] When a piece of continuous information to be reproduced has
a size greater than a predetermined size, the system controller 14
transmits a control signal to the switch 114 to switch to a side L,
i.e., for CLV control. When a piece of continuous information to be
reproduced has a size smaller than the predetermined size, the
system controller 14 transmits a control signal to the switch 114
to switch to a side A, i.e., for CAV control. The above-described
predetermined size is the lower limit of the information length
range of continuous information which is judged to be suitable for
reproduction using CLV control or the upper limit of the
information length range of continuous information which is judged
to be suitable for reproduction using CAV control, depending on the
purposes of the use of the information and considering reproduction
performance, access performance, vibration noise of a spindle
motor, and the like. The same is applied to the following
Embodiments 3 and 4 of the present invention.
[0063] In the present invention, the system controller 14 functions
as an information determination section for detecting the
information length of continuous information, and a rotation
control selection section for selectively operating a CLV control
section or a CAV control section. A signal which has been subjected
to error correction and demodulation by the demodulation circuit 13
is reproduced by a host PC 15 (reproduction signal processing
section) with a well-known method.
[0064] In this manner, reproduction by CAV control and reproduction
by CLV control are switched, depending on the continuity
(information length) of information to be recorded, thereby
efficiently reproducing information on a disk. Information is
recorded to an appropriate place of the optical disk, depending on
its size, so that information can be efficiently reproduced using
CLV/CAV control. Specifically, for example, audio or video data
having a large information length to be continuously reproduced is
generally recorded at the inner circumference side of a disk, while
code information having a small information length to be
continuously reproduced is generally recorded at the outer
circumference side of the disk (this is described in detail later
in Embodiment 3). Specifically, CLV control holding a required
reproduction velocity is performed for audio or video data, while
CAV control is performed for code information so that fast-speed
random access is achieved.
[0065] In the above description, continuous information having an
information length greater than a predetermined size is reproduced
using CLV control. The present invention is not limited to this.
Instead of CLV control, CAV control in which the number of
revolutions is limited to a constant range may be used to reproduce
continuous information having a large information length. A
constant range of the number of revolutions refers to the number of
revolutions which is as low as that in which a transfer rate
(reproduction rate) required for reproduction of information
recorded in the most inner circumference of a disk can be secured,
for example. This constant range is preferably about 1.5 to 3 times
as large as the number of revolutions of a disk corresponding to a
minimum transfer rate required for reproduction of information
recorded in the most inner circumference of the disk, taking into
consideration a balance among the margin of the transfer rate,
vibration of a rotating section, and the like. For example, about
1.5 times may be for a reproduction apparatus having large
vibration. About 3 times may before are production apparatus having
small vibration. With CAV control having the low number of
revolutions, a required reproduction rate can be secured for
continuous information having a large size.
[0066] Further, the present invention can be used no matter as to
whether two kinds of information requiring different rotational
driving control methods, i.e., continuous information having an
information length larger than a predetermined size and continuous
information having an information length less than the
predetermined size, are stored on the same disk or different
disks.
Embodiment 2
[0067] Hereinafter, an information reproduction apparatus and its
reproduction method according to another embodiment of the present
invention will be described.
[0068] In Embodiment 1, the switching between CLV control and CAV
control is performed based on the size of continuous information.
In Embodiment 2, the switching is performed based on the type of
information (audio/video information or code information).
Particularly, whether or not information is moving image
information is determined before reproduction of moving image
information. Based on the result, an optimal reproduction rate is
provided so that appropriate rotation control can be performed.
Whether or not information to be reproduced is moving image
information is determined with high probability by recognizing
additional information and contents relating to functions recorded
in a disk other than the moving image information.
[0069] A configuration of the information reproduction apparatus of
Embodiment 2 is basically similar to that shown in FIGS. 1 and 2
relating to Embodiment 1. Therefore, a description thereof is here
omitted. Hereinafter, a fundumental operation of the switching
between CLV/CAV control will be briefly described.
[0070] The system controller 14 (FIG. 1) transmits a control signal
to the switch 114 in the spindle control circuit 9 to switch to a
side L, i.e., for CLV control, when information to be reproduced is
moving image information. Alternatively, the system controller 14
transmits a control signal to the switch 114 in the spindle control
circuit 9 to switch to a side A, i.e., for CAV control. In this
case, in the CAV control, the number of revolutions is limited to a
low level where a transfer rate required for reproduction of
information recorded in the most inner circumference of a disk can
be secured. In other words, the number of revolutions is limited to
a velocity which causes substantially no problem in processing for
sound reproduction. This low-level range is preferably about 1.5 to
3 times as large as the number of revolutions of a disk
corresponding to a minimum transfer rate required for reproduction
of information recorded in the most inner circumference of the
disk, taking into consideration a balance among the margin of the
transfer rate, vibration of a rotating section, and the like. For
example, about 1.5 times may be for a reproduction apparatus having
large vibration. About 3 times may be for a reproduction apparatus
having small vibration.
[0071] As described above, if it is verified that information to be
reproduced is moving image information, a mode for securing a
maximum transfer rate (CAV control) is switched to a mode for
securing a transfer rate required for reproduction of moving images
(CLV control, or CAV control in which the above-described number of
revolutions is limited). Therefore, vibration of a mechanism or a
disk, or rotation noise or wind noise of a motor can be reduced as
much as possible.
[0072] Hereinafter, a description will be given of a method for
determining whether information to be reproduced is moving image
information or information other than a moving image.
[0073] [Identification of Moving Image Information Based on
Information Length]
[0074] The system controller 14 determines that information to be
reproduced is moving image information, when the information length
of continuous information to be reproduced is greater than or equal
to about 1 GB.
[0075] A file size indicating whether or not the information length
is greater than or equal to 1 GB is recorded as information in a
management area at a predetermined position on the disk 1. When an
apparatus is activated, the management area is read out, and the
file size is stored in RAM (Random Access Memory) in the system
controller 14 along with a title, a volume name, and a recording
position addresson the disk 1. When this information is actually
reproduced, whether or not the file size is greater than or equal
to 1 GB is determined based on the management information stored on
the RAM. When the file size is greater than or equal to 1 GB, the
information is presumed to be moving image information, and
rotational driving control is performed based on the
above-described configuration and sequence. Specifically, CLV
control, or CAV control in which the number of revolutions is
limited, is performed. This method for identifying moving image
information can be applied to both a ROM disk and a RAM disk.
[0076] [Identification of Moving Image Information using a
Specialized Command for Moving Image Information]
[0077] The system controller 14 determines that information to be
reproduced is moving image information, when an AV read command
which is a moving image information read only command is
transmitted from a host PC 15.
[0078] When it is determined that information to be reproduced is
moving image information, the rotation control of the spindle motor
2 is switched in execution of the AV read command as described
above. Since it is not necessary to additionally issue a control
command from the host PC 15 to reduce the number of revolutions,
the overhead of communication with the host PC 15 can be reduced.
This method for identifying moving image information can be applied
to both a ROM disk and a RAM disk.
[0079] [Identification of Moving Image Information Baed on Regional
Code]
[0080] The system controller 14 typically attempts to obtain a
regional code stored in the disk 1 during spin-up. Regional codes
are grouped into 6 regions shown in Table 1 below, so that regions
in which information can be reproduced are limited. When the
regional code is recorded, it is determined that information to be
reproduced is moving image information, and the rotation control of
the spindle motor 2 is switched as described above during or
immediately after spin-up. This method for identifying moving image
information can be applied to a ROM disk.
1TABLE 1 1: U.S., Canada, U.S. Territories 2: Japan, Europe,
SouthAfrica, MiddleEast (includingEgypt) 3: Southeast Asia, East
Asia (including Hong Kong) 4: Australia, NewZealand,
PacificIslands, CentralAmerica, Mexico, South America, Caribbean 5:
EasternEurope (FormerSovietUnion), IndianSubcontinent, Africa (also
North Korea, Mongolia) 6: China
[0081] [Identification of Moving image Information Based on Defect
Management Information]
[0082] In the case of a recordable disk, defect management
information used to manage a defective sector is registered in a
DMA (Defect Management Area) on the disk 1 in order to prevent
false recording or recording failure to a defective sector so as to
secure reliability. When a defective sector is present, a recording
destination is changed from the defective sector to an alternate
sector in which recording is performed. In the case of moving image
information requiring the temporal connectivity (continuity) of a
file, the change of a recording destination leads to system
failure. Therefore, even if false recording or recoding failure
occurs to some extent, recording is just continued so that
exchanging is not performed. Such a method has been proposed.
[0083] For a disk adopting this proposal, the system controller 14
obtains defect management information from a DMA when the apparatus
is activated, thereby determining that information to be reproduced
is moving image information when there is no registered defect
management information. Based on the determination, the rotation
control of the spindle motor 2 is switched as described above. This
method for identifying moving image information can be applied to a
RAM disk.
[0084] [Identification of Moving Image Information Based on the
Contents of the Head Portion of Information]
[0085] The type of information (audio information, video
information, or code information) recorded in the CONTENTS 34 (see
FIG. 3) in the header portion 37 of information is detected by the
system controller 14, so that it can be determined whether or not
information to be reproduced is moving image information. Based on
the determination, the rotation control of the spindle motor 2 is
switched as described above. This method of identifying moving
image information can be applied to both a ROM disk and a RAM
disk.
[0086] [Identification of Moving Image Information Based on
Recorded Contents Regarding to the Type of File]
[0087] The type of file is previously recorded as information in a
management area at a predetermined position on the disk 1. When an
apparatus is activated, the management area is read out, and the
file size is stored in RAM in the system controller 14 along with a
title, a volume name, and a recording position address written on
the disk 1. When this information is actually reproduced,
information to be reproduced is estimated to be moving image
information if it is determined by the system controller 14 based
on the management information stored in the RAM that the extension
of reproduced information is MPEG (Motion Picture Expert Group) or
VOB (Video Object). Similar to the above-described configuration
and sequence, based on the determination, the rotation control of
the spindle motor 2 is switched. This method of identifying moving
image information can be applied to both a ROM disk and a RAM
disk.
[0088] [Identification of Moving Image Information Based on Code
Information for Limiting Reproduction]
[0089] When information to be reproduced is restrained under a
parental lock in order to limit reproduction of contents including
violence, sexual scenes or the like, or when information to be
reproduced includes information having a screen size of 16:9 letter
box peculiar to movies, the information to be reproduced can be
estimated to be moving image information by the system controller
14. Based on the determination, the rotation control of the spindle
motor 2 is switched as described above. This method of identifying
moving image information can be applied to a ROM disk.
[0090] [Identification of Moving Image Information Based on
BCA]
[0091] In the case of a ROM disk which is a reproduction only disk,
it is difficult to provide a management area in disk stamping and
store a flag indicating a moving image or a moving image file size
in terms of capacity and compatibility. Taking this into
consideration, the information that recorded information is moving
image information is recorded in a BCA (Burst Cutting Area) in a
most inner circumference of a disk. By reading the BCA at a
required timing, whether or not information to be reproduced is
moving image information is determined by the system controller 14.
Based on the result of the determination, the rotation control of
the spindle motor 2 is switched as described above. This method of
identifying moving image information can be applied to both a ROM
disk and a RAM disk.
[0092] [Identification of Moving Image Information Based on
Authentication of Information]
[0093] Moving image information to be reproduced often has
copyright. Therefore, when information is authenticated, it is
estimated by the system controller 14 that information to be
reproduced is moving image information. Based on this estimation,
the rotation control of the spindle motor 2 is switched as
described above. This method of identifying moving image
information can be applied to both a ROM disk and a RAM disk.
[0094] The above description relates to the case where the
information reproduction apparatus per se identifies moving image
information and the rotational driving control of a disk is
switched. Other than such identification/switching methods, the
user may identify the type of information by noting the title of
information to determine whether or not the information is a moving
image for appreciation, whether or not the information is code
information for installing, or the like (i.e., the purpose of use).
Therefore, a moving image switch may be attached to the information
reproduction apparatus, and the user may turn the switch ON in the
case of moving image information. In this case, CLV control for a
moving image, or CAV control in which a transfer rate is secured
for reproduction of a moving image at the most inner circumference,
can be easily selected.
[0095] As described above, to estimate whether or not information
is a moving image, necessary information can be obtained by reading
a management area or the like, which includes additional
information or functions, instead of moving image information to be
reproduced. Further, a switch is provided in order for the user to
have an opportunity to select type of information, such that moving
image information can be identified with a higher probability.
Thus, the type of information is identified and an appropriate
rotational driving control is performed, thereby making it possible
to minimize noise and vibration generated from the apparatus.
[0096] The present invention can be used no matter as to whether
two kinds of information requiring different rotational driving
control methods, i.e., moving image information and information
other than moving image information, are stored on the same disk or
different disks.
Embodiment 3
[0097] Hereinafter, an information carrier (disk) according to
Embodiment 3 of the present invention will be described. FIG. 4 is
a plan view showing the information carrier of Embodiment 3.
[0098] The information carrier recording carrier of the present
invention includes a plurality of information recording areas
(areas 1 and 2) separated along a radial direction of the
information carrier as shown in FIG. 4. Information is recorded in
each of these information recording areas, depending on the
information length of continuous information. Specifically,
information having an information length of continuous information
larger than a predetermined size, such as audio information and
video information, is recorded in the area 1 in the inner
circumference side of the information carrier, while information
having an information length of continuous information smaller than
the predetermined size, such as a short file (i.e., code
information), is recorded in the area 2 in the outer circumference
side of the information carrier. If an information length of
information to be continuously reproduced has a length larger than
the predetermined size, the information is recorded in the area 1
in the inner circumference side even in the case of code
information. The widths in a radial direction of areas 1 and 2 are
appropriately adjusted, depending on the amount of informatin to be
recorded in the respective areas.
[0099] The structure of the information carrier of Embodiment 3 has
the following meaning.
[0100] A disk in which information is to be recorded (or has been
record) with CLV control is subjected to CAV control, where the
disk is rotated at a constant number of revolutions, so that as the
track is closing to the outer circumference, the reproduction rate
is increased. The upper limit of the reproduction rate is generally
determined by a frequency characteristic of an optical pickup or a
signal processing circuit and the maximum number of revolutions of
a spindle motor. Therefore, when random access for code information
is performed in an outer circumference and sequential access for
audio/video information is performed in an inner circumference,
handling or access performance and reading performace can be
expected to be substantially improved.
[0101] In view of this, information is disposed in the information
carrier of the present invention, depending on the size of
continuous information as described above. Information on a disk
can be efficiently reproduced using the information reproduction
apparatuses described in Embodiments 1 and 2. Information having a
large size of continuous information, such as audio or video data,
can be reproduced with CLV control having a required reproduction
rate (or CAV control having a limited number of revolutions as
described in Embodiment 2), while information having a small size
of continuous information, such as code information, can be
reproduced with CAV control while performing fast random
access.
[0102] When information is recorded in the information carrier of
Embodiment 3, a SIB (Size Information Block) area 50 may be
effectively provided at a most inner circumference of a disk so as
to further easily switch between CLV/CAV control. FIG. 5 shows a
format of information on an information recording area, with which
information is recorded depending on the size of information
(continuous information) to be continuously reproduced, that is
recorded in the SIB (Size Information Block) area 50.
[0103] As shown in FIG. 5, the SIB area includes a portion 51 for
storing a value of the total number of areas in a disk, a portion
52 for storing the leading address of the area 1, a portion 53 for
storing the minimum size of a file recorded in the area 1, i.e.,
the threshold values of the areas 1 and 2, a portion 54 for storing
the leading address of the area 2, and a portion 55 for storing the
minimum size of a file recorded in the area 2, i.e., the minimum
size of continuous information to be continuously reproduced. When
this SIB information is read out and stored upon activation of an
apparatus, the switching between the areas 1 and 2, i.e., between
CAV control and CLV control (or CAV control of Embodiment 2 which
limits the number of revolutions) can be even more easily
performed.
[0104] Although, in Embodiment 3, it is described that two areas
(the areas 1 and 2) are provided for recording information to be
reproduced, three or more areas may be provided for recording
information, depending on types or sizes of files. In this case,
the total number of areas is stored in the area 51, and the leading
address, the minimum size, etc., of an area 3 are stored in an
extended area.
[0105] Hereinafter, a specific embodiment in which information is
recorded using the information carrier of FIG. 4 and is further
reproduced will be described.
EXAMPLE 1
[0106] A description will be given of a first example, in which it
is assumed that music information having a total size of 1 GB when
it is continuously reproduced, such as a 3D-stereo recording
Beethoven's "Choral", is recorded in the area 1, and a variety of
text or code information of 1 MB or less including Beethoven's
personal history, music scores, performers profiles, and/or
pictures is recorded in the area 2. The areas 1 and 2 range, for
example, in radius from about 24 mm to 35 mm and from about 35 mm
to 58 mm, respectively. FIG. 6 shows a relationship between the
areas 1 and 2 as to the number of revolutions and the transfer rate
(reproduction rate).
[0107] When music is appreciated, the area 1 at the inner
circumference side is accessed, CLV control is selected, and
information recorded in a track is sequentially read out. A light
beam is moved toward the outer circumference along a spiral track
while reading out information with the laspe of time. The rotation
of the spindle motor 2 (FIG. 1) is linearly decreased so as to
maintain a constant linear velocity. The number of revolutions is
equal to A (rpm) at the leading radius of 24 mm of the area 1 and
is reduced up to B (rpm) at the end radius of 35 mm. In this case,
the transfer rate is controlled by CLV control in such a manner as
to be a constant value (aMB/s). Further, the rotation of the
spindle motor may be further decreased up to a minimum reproduction
rate (required for processing during sound reproduction without a
problem) by performing the CLV control, thereby making it possible
to reduce the rotation noise of the spindle.
[0108] Data relating to music other than the music per se is
recorded in the area 2. The required data is randomly accessed by a
host application. A host recognizes the leading address of the area
2 according to the SIB information. Therefore, when starting access
to the area 2, the host switches the CLV control to CAV control for
the spindle motor so that the number of revolutions is constant (A
rpm). A light beam is moved with in the area 2 as required while
reading out data recorded therein. In this case, as the track is
closing to the outer circumference, the transfer rate (reproduction
rate) is increased, and the response time of the spindle motor is
zero due to CAV control, whereby considerably fast access can be
achieved in the area 2.
SECOND EXAMPLE
[0109] A description will be given of a second example, in which it
is assumed that information having a large size and requiring a
fast read rate, such as high-quality image information, is recorded
in the area 1, while a variety of information including a reduced
image, a control program, or other code information are recorded in
the area 2. The widths of the areas 1 and 2 are set to the same
sizes as those of Example 1.
[0110] As with the case where recorded information is audio
information, information in the area 1 is reproduced with CLV
control while information in the area 2 is reproduced with CAV
control. It should be noted that a read rate is important for image
information unlike audio information, so that the linear velocity
of CLV control in the area 1 is set to as high a value as possible
while taking into consideration a frequency characteristic of an
optical pickup or a signal processing circuit and the maximum
number of revolutions of a spindle motor. A relationship between
the areas 1 and 2 as to the number of revolutions and the transfer
rate (reproduction rate) is shown in FIG. 7.
[0111] In the area 1 in which sequential reading is predominant,
the number of accesses is small, so that reading performace is
paramount and the spindle motor 2 is therefore controlled in such a
manner that reading is performed with CLV control and at a fast and
constant transfer rate (aMB/s) In the area 2 in which random access
is predominant, access performance is paramount and therefore the
number of revolutions of the spindle motor 2 is set to be constant
(C rpm) with CAV control so that fast access can be achieved.
[0112] Thus, information to be continuously reproduced (continuous
information), i.e., a file having a large size is recorded in an
area at the inner circumference side of the disk, while continuous
information to be randomly reproduced, i.e., a file having a small
size is recorded in an area at the outer circumference side.
Therefore, information on a single disk can be effectively
reproduced in terms of an access speed, noise and a read rate.
Embodiment 4
[0113] Next, an information recording apparatus for recording
information onto the disk (FIG. 4) of Embodiment 3 and a method
used therein will be described as Embodiment 4 of the present
invention. FIG. 8 is a block diagram showing a configuration of the
information recording apparatus of Embodiment 4. Parts similar to
those of the information reproduction apparatus of Embodiment 1 are
indicated by the same numerals and a description thereof is thus
omitted.
[0114] Information recorded in the host PC 15 (recorded
information) is transferred to an encoder 23. The recorded
information is subjected to scrambling and modulation, and the
resultant information is modulated into a signal indicating the
intensity of laser light by a LD (Laser Diode) modulation circuit
21. The signal is transferred via a LD (Laser Diode) drive circuit
20 to the optical pickup 3 (also serves as a recording section).
Marks are recorded in a track on the disk 1 by modulating laser
light having recording power which is about 10 times as strong as
reproducing power. In this case, the host PC 15 transmits to a
system controller 14 an information length signal indicating the
continuity of information to be recorded. In accordance with the
information length signal, the system controller 14 transmits an
instruction to the control circuit 8, so that an area to be
recorded and a track in the area are selected.
[0115] For example, when music information having a large size of
continuous information is recorded, a light beam is shifted by a
traverse motor 4 to the area 1 at the inner circumference side of
the disk. The continuous music information is recorded in an
appropriate empty track of the area 1. When code information having
a small size of continuous information is recorded, a light beam is
shifted by the traverse motor 4 to the area 2 at the outer
circumference side. The continuous code information is recorded in
an appropriate empty track of the area 2. Therefore, a large size
of information to be continuously reproduced is recorded in the
area 1 at the inner circumference side, while a small size of
information to be continuously reproduced is recorded in the area 2
in the outer circumference side. Whether the size of continuous
information is large or small can be determined using about 1 GB as
a criterion, for example.
[0116] In Embodment 4, for recording, the spindle motor 2 is
preferably controlled in such a manner as to record information to
be continuously recorded or reproduced, such as audio information,
with CLV control and information to be randomly reproduced, such as
code data, with CAV control. A control method used in recording may
be stored in the form of bit information as additional information
in a header portion. In this case, CAV control and CLV control can
be switched based on such bits when reproduction is performed.
[0117] Further, when the response time of laser or recording
compensation are taken into consideration, a modulation frequency
needs to be increased as the track is closing to the outer
circumference in the case where recording is performed with CAV
control. It is difficult to achieve this when a recording density
and a transfer rate are certain values. In this case, all recording
is performed with CLV control, and only reproduction is performed
with CAV control and CLV control which are swithecd there between
depending on information.
Industrial Applicability
[0118] As described above, according to the information
reproduction apparatus of the present invention, CAV control and
CLV control are switched between depending on properties of the
information, such as the size or type of continuous information to
be continuously reproduced. Therefore, information recorded on a
single disk or different disks can be reproduced with appropriate
rotational driving control depending on the properties, thereby
making it possible to improve access performance. Since rotation is
not increased more than necessary for the properties of the
information, noise or vibration of the apparatus due to rotation of
a spindle motor is reduced.
[0119] Further, according to the information carrier and the
information recording apparatus of the present invention, data
having a large size of continuous information to be continuously
reproduced is recorded at the inner circumference side of a disk,
while data having a small size of continuous information to be
continuously reproduced is recorded at the outer circumference side
of the disk. Therefore, an even higher level of access performance
can be achieved in reproduction. According to the information
carrier of the present invention, continuous information, such as
music and video, is previously recorded in an inner circumference
area of a disk as pit information in the form of pits and lands.
Subsequently, information created by a user, or the like can be
additionally recorded in an outer circumference area of a disk. The
rotation of such a partial ROM disk can be easily controlled in
reproduction/recording according to the present invention.
* * * * *