U.S. patent application number 11/594845 was filed with the patent office on 2007-03-15 for disk drive system employing effective disk surface stabilization mechanism.
Invention is credited to Yasutomo Aman, Shozo Murata, Nobuaki Onagi.
Application Number | 20070058500 11/594845 |
Document ID | / |
Family ID | 27554926 |
Filed Date | 2007-03-15 |
United States Patent
Application |
20070058500 |
Kind Code |
A1 |
Onagi; Nobuaki ; et
al. |
March 15, 2007 |
Disk drive system employing effective disk surface stabilization
mechanism
Abstract
A stabilization part stabilizes surface vibration of a flexible
optical disk along a rotation axis direction of the optical disk by
means of pressure difference of air flow created according to
Bernoulli's law at a portion on which information writing/reading
is performed, provided on a side of the optical disk opposite to a
side on which information recording/reproducing is performed. In
this case, areas are provide on the upstream side and down stream
side along the disk rotation direction of the portion of the
optical disk which is stabilized by said stabilization part, said
areas of the optical disk not having pressure difference created
thereon by the air flow.
Inventors: |
Onagi; Nobuaki; (Kanagawa,
JP) ; Aman; Yasutomo; (Kanagawa, JP) ; Murata;
Shozo; (Kanagawa, JP) |
Correspondence
Address: |
DICKSTEIN SHAPIRO LLP
1825 EYE STREET NW
Washington
DC
20006-5403
US
|
Family ID: |
27554926 |
Appl. No.: |
11/594845 |
Filed: |
November 9, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10123006 |
Apr 16, 2002 |
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11594845 |
Nov 9, 2006 |
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Current U.S.
Class: |
369/30.65 ;
G9B/11.032; G9B/33.024; G9B/5.198; G9B/7.041; G9B/7.065;
G9B/7.094 |
Current CPC
Class: |
G11B 7/0953 20130101;
G11B 7/0956 20130101; G11B 19/2081 20130101; G11B 23/005 20130101;
G11B 21/12 20130101; G11B 23/0035 20130101; G11B 7/0037 20130101;
G11B 19/042 20130101; G11B 7/0946 20130101; G11B 5/5582 20130101;
G11B 11/1055 20130101; G11B 7/08 20130101; G11B 33/08 20130101 |
Class at
Publication: |
369/030.65 |
International
Class: |
G11B 21/08 20060101
G11B021/08 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 17, 2001 |
JP |
2001-118344 |
May 28, 2001 |
JP |
2001-158663 |
Jul 30, 2001 |
JP |
2001-228943 |
Aug 24, 2001 |
JP |
2001-253896 |
Sep 19, 2001 |
JP |
2001-284299 |
Jan 28, 2002 |
JP |
2002-018323 |
Claims
1.-140. (canceled)
141. A cartridge for holding a plurality of disks, the cartridge
comprising: a cartridge body having a width, a depth and a height;
a plurality of disk trays arranged inside said cartridge body; and
wherein each of said plurality of disk trays has an identification
part.
142. The cartridge of claim 141, wherein each said identification
part on each of said plurality of disk trays is spaced laterally
along said width of said cartridge body.
143. The cartridge of claim 141, wherein each of said plurality of
disk trays has an engagement portion for sliding said disk tray in
and out of said cartridge body.
144. The cartridge of claim 143, wherein said engagement portion is
an opening.
145. The cartridge of claim 144, wherein said opening is formed in
said identification part.
146. The cartridge of claim 141, wherein said plurality of disk
trays hold flexible optical disks.
147. The cartridge of claim 141, wherein said plurality of disk
trays are adapted to be identified and accessed by a disk placement
mechanism.
148. A cartridge for holding a plurality of disks, the cartridge
comprising: a cartridge body having a width, a depth and a height;
a plurality of disk trays arranged inside said cartridge body; an
identification part on each of said plurality of disk trays; and an
opening in each of said identification parts.
149. The cartridge of claim 148, wherein each said identification
part on each of said plurality of disk trays is spaced laterally
along said width of said cartridge body.
150. The cartridge of claim 148, wherein said plurality of disk
trays are adapted to be identified and accessed by a disk placement
mechanism.
151. The cartridge of claim 148, wherein said plurality of disk
trays hold flexible optical disks.
152. A cartridge for holding a plurality of disks, the cartridge
comprising: a cartridge body having a width, a depth and a height;
a plurality of disk trays arranged inside said cartridge body; and
wherein each of said plurality of disk trays has an identification
part, each said identification part being spaced laterally at
different positions along said width of said cartridge body.
153. The cartridge of claim 152, wherein each of said plurality of
disk trays has an engagement portion for sliding said disk tray in
and out of said cartridge body.
154. The cartridge of claim 153, wherein each said engagement
portion is a hole in said identification part.
155. The cartridge of claim 152, wherein said plurality of disk
trays hold flexible optical disks.
156. The cartridge of claim 152, wherein said plurality of disk
trays are adapted to be identified and accessed by a disk placement
mechanism.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a disk drive system
employing a disk surface stabilization mechanism, and, in
particular, an optical disk drive for carrying out rotation drive
of an optical disk which is an optical information recording medium
in a form of sheet which has a flexibility, an optical information
recording device, an optical information reproduction device, and a
disk cartridge used therefor.
[0003] 2. Description of the Related Art
[0004] Optical disks are demanded to store mass digitized data, as
digitization of television broadcasting starts in recent years. A
basic method of improving recording density on the optical disks is
to reduce the diameter of a beam spot used for
recording/reproduction information onto/from the optical disk.
[0005] For this reason, it is effective to shorten in wavelength of
light used for recording/reproduction, and also, it is effective to
enlarge numerical aperture NA of an object lens applied there. As
for the wavelength of light, the wavelength of approximately 650 nm
of red light is used on DVD while 780 nm of near infrared light is
used on CD. Recently, a semiconductor laser of purple-blue light
has been developed and it is expected that approximately 400 nm
laser light will be practically used.
[0006] Moreover, the object lens for CD has less than 0.5 NA while
the object lens for DVD has approximately 0.6 NA. It is demanded
that the numeral aperture (NA) be enlarged further to 0.7 or more,
from now on. However, enlarging NA of the object lens and
shortening the wavelength of light may result in increase in
influence of aberration in case the light applied is weakened.
Therefore, the margin of tilt on the optical disk may decrease.
Moreover, since the depth of focus becomes smaller by enlarging NA,
it will be necessary to increase focus servo accuracy in the
optical disk drive.
[0007] Furthermore, since the distance between the object lens and
record surface of an optical disk becomes smaller by using the
object lens of high NA, the object lens and optical disk may
collide before focus servo control operation at the beginning
thereof, unless surface vibration or axial runout on the disk is
sufficiently controlled.
[0008] For example, as the O PLUS E (vol. 20, No. 2) discloses on
page 183, as a large-capacity optical disk drive system having a
short wavelength and high NA, a record film is formed on a rigid
and thick substrate as in CD, and, light for recording/reproducing
is not made to pass through the substrate, but
recording/reproducing is made onto the record film through a thin
cover layer is proposed.
[0009] Moreover, Japanese laid-open patent application No. 7-105657
and Japanese laid-open patent application No. 10-308059 disclose a
method of stabilizing surface vibration on optical disk as a result
of a flexible optical disk being rotated on a specially provided
stabilization plate having a plane surface.
[0010] However, in case the substrate of optical disk is made of a
rigid body, it is necessary to manufacture the optical disk at a
very high accuracy and also to from the record film at a very low
temperature condition in order to sufficiently reduce surface
vibration and/or tilt of the disk which is rotating at high speed.
Such requirements may reduce the yield of products, which may
result in cost rise of optical disks.
[0011] Moreover, by the method for rotating an optical disk with
flexibility on the stabilization plate, if it is made to rotate on
a simple plane surface as disclosed by Japanese laid-open patent
application No. 10-308059, the optical disk and the stabilization
plate may touch and slide. For this reason, the optical disk may
vibrate, and surface vibration at high frequency may occur. Such a
type of surface vibration at high frequency may fall in a frequency
range for which mechanical focus servo control cannot deal with,
and, thereby, residual servo error may not be sufficiently
eliminated.
[0012] Furthermore, if the optical disk and object lens slide
mutually due to surface vibration, dirt/dust may be generated
thereby, which then may cause various error. Especially, as
Japanese laid-open patent application No. 7-105657 discloses, the
record film of an optical disk may be damaged in the case the
record film is provided on the side facing the stabilization plate,
which may directly result in recording/reproducing error.
SUMMARY OF THE INVENTION
[0013] An object of the present invention is to provide an optical
disk drive which solves the above-mentioned problems, can eliminate
surface vibration of the optical disk by means of air force, can
enable high-density record in case recording/reproduction is
performed using an optical disk in a form of flexible sheet, and
can prevent generating of error such as that caused due to slide
contact to the object lens, optical information recording device,
optical information reproducing device, and a disk cartridge used
therefor.
[0014] An optical disk drive according to the present invention
comprises:
[0015] a driving part driving a flexible optical disk; and
[0016] a stabilization part, stabilizing vibration of the optical
disk along the rotation axis direction of the optical disk by means
of pressure difference of air flow created according to Bernoulli's
law at a portion of the optical disk on which information
writing/reading is performed, provided on a side of the optical
disk opposite to a side on which information recording/reproducing
is performed,
[0017] wherein areas are provide on the upstream side and down
stream side along the disk rotation direction of the portion of the
optical disk which is stabilized by said stabilization part, said
areas of the optical disk acting as escapes having no pressure
difference created thereon by the air flow.
[0018] By providing the areas of the optical disk having no
pressure difference created due to the air flow according to
Bernoulli's low caused by the stabilization part, these areas
acting as `escape`, and thus, it is possible to effectively reduce
repulsive force occurring in the portion at which the stabilization
effect should be performed on by means of the stabilization part.
Thus, the stabilization effect there can be increased
effectively.
[0019] According to another aspect of the present invention, an
information recording/reproducing device comprises:
[0020] a head mechanism provided on one side of a flexible disk
recording medium and performing information recording/reproducing
onto the disk recording medium;
[0021] a guide member provided on the other side of the disk
recording medium and controlling positional change such as surface
vibration of the disk recording medium; and
[0022] a projection amount control mechanism controlling a
projection amount of said guide member with respect to the disk
recording medium.
[0023] Thereby, it is possible to effectively reduce the required
movable range of the object lens, thus to reduce the weight of the
optical head, and, thereby, to achieve the optical head having
improved high-frequency response performance.
[0024] According to another aspect of the present invention, a
method of controlling an optical recording/reproducing device which
comprises a driving part driving and rotating a flexible optical
disk; a pickup performing optical reading/writing onto a recording
surface of the optical disk; and a stabilization guide member
provided on a side of the optical disk opposite to a side of the
recording surface, and stabilizing surface vibration of the optical
disk at a portion on which writing/reading is performed by means of
pressure difference of air flow according to Bernoulli's law,
comprises the step of:
[0025] controlling tilt angles of the stabilization guide member
along a disk radius direction and along a disk rotation tangential
direction.
[0026] Thereby, it is possible to accurately control an area on the
optical disk at which the stabilization effect caused by the
stabilization guide member is most effectively performed on, and,
thus, it is possible to perform recording/reproducing on a desired
area of the optical disk which area is best stabilized from surface
vibration, and, thus, to achieve high-quality information
recording/reproducing.
[0027] According to another aspect of the present invention, a
method of controlling an optical recording/reproducing device which
comprises a driving part driving and rotating a flexible optical
disk; and a stabilization guide member provided on a side of the
optical disk opposite to a side of a recording surface, and
stabilizing surface vibration of the optical disk at a portion on
which writing/reading is performed by means of pressure difference
of air flow according to Bernoulli's law, comprises the step
of:
[0028] controlling a position of the stabilization guide member
along a disk rotation axis direction based on a position of a
portion of the optical disk on which writing/reading is performed
and rotation speed of the optical disk.
[0029] In this method, it is preferable that a surface vibration
stabilization state is previously measured on case of changing the
position of the stabilization guide member along the disk
rotational axis direction and disk rotation speed for particular
types of optical disk, then, based thereon, a pattern on the
above-mentioned positional control of the stabilization guide
member is previously set for the particular types of optical disk,
and, thus, the pattern applied is selected according to the type of
optical disk applied.
[0030] Thereby, it is possible to properly and positively control
surface vibration on the optical disk by means of the stabilization
guide member at an arbitrary portion of the optical disk which
information recording/reproducing is performed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Other objects and further features of the present invention
will become more apparent from the following detailed description
when read in conjunction with the accompanying drawings:
[0032] FIG. 1 shows a side-elevational sectional view of an optical
information recording/reproducing device in a first embodiment of
the present invention;
[0033] FIGS. 2A and 2B illustrate a recording part and a
reproducing part of an optical pickup shown in FIG. 1;
[0034] FIG. 3 illustrates a side-elevational sectional view of an
optical disk shown in FIG. 1;
[0035] FIG. 4 illustrates a stabilization effect on surface
vibration of the optical disk according to the first embodiment of
the present invention;
[0036] FIG. 5 illustrates a measurement result on surface vibration
in the configuration shown in FIG. 4;
[0037] FIG. 6 shows a flow chart of recording/reproducing operation
in the recording/reproducing device shown in FIG. 1;
[0038] FIG. 7 illustrates a variant embodiment of a stabilization
guide member shown in FIG. 4;
[0039] FIG. 8 illustrates an example of disposition of the
stabilization guide members in the first embodiment of the present
invention;
[0040] FIG. 9 illustrates another example of disposition of the
stabilization guide members in the first embodiment of the present
invention;
[0041] FIG. 10 illustrates another example of disposition of the
stabilization guide members in the first embodiment of the present
invention;
[0042] FIG. 11 shows a side-elevational sectional view of an
optical information recording/reproducing device in a second
embodiment of the present invention;
[0043] FIG. 12 shows a side-elevational sectional view of an
optical information recording/reproducing device in a third
embodiment of the present invention;
[0044] FIG. 13 illustrates a plan view showing a shape and position
of the stabilization guide member shown in FIG. 12;
[0045] FIG. 14 illustrates a disk cartridge in a fourth embodiment
of the present invention;
[0046] FIG. 15 shows a side-elevational sectional view of the disk
cartridge shown in FIG. 14;
[0047] FIGS. 16A, 16B, 17, 18A, 18B, 19, 20 and 21 illustrate
various examples of specific configurations of the stabilization
guide members according to the present invention;
[0048] FIG. 22 shows a side elevational view of an information
recording/reproducing device in a fifth embodiment of the present
invention;
[0049] FIG. 23 shows a side elevational view around a guide member
shown in FIG. 22;
[0050] FIG. 24 shows a side elevational sectional view of an
flexible optical disk applied to the device shown in FIG. 22;
[0051] FIG. 25 shows a block diagram of a servo control system
except a signal processing system in the device shown in FIG.
22;
[0052] FIG. 26 shows a block diagram of a variant embodiment of the
servo control system shown in FIG. 22;
[0053] FIG. 27 shows a block diagram of another variant embodiment
of the servo control-system shown in FIG. 22;
[0054] FIG. 28 shows a side elevational sectional view of an
optical information recording/reproducing device in a seventh
embodiment of the present invention;
[0055] FIG. 29 illustrates a measurement result on surface
vibration measured on the device shown in FIG. 28;
[0056] FIG. 30 shows a side elevational sectional view of an
optical information recording/reproducing device in a comparison
example with respect to the seventh embodiment;
[0057] FIG. 31 illustrates a relationship between a position of the
stabilization guide member and surface vibration stabilization
position in the comparison example shown in FIG. 30;
[0058] FIG. 32 shows a side elevational sectional view of an
optical information recording/reproducing device in an eighth
embodiment of the present invention;
[0059] FIG. 33 shows a side elevational sectional view of an
optical information recording/reproducing device in a ninth
embodiment of the present invention;
[0060] FIG. 34 illustrates a guide movement path, a pickup movement
path, a stabilization point movement path, a guide movement path
inclination angle, a pickup movement path inclination angle and a
stabilization point movement path inclination angle in the ninth
embodiment of the present invention;
[0061] FIG. 35 illustrates the guide movement path and
stabilization point movement path in the ninth embodiment of the
present invention;
[0062] FIG. 36 illustrates a side elevational view of the guide
movement path and pickup movement path in the ninth embodiment of
the present invention;
[0063] FIG. 37 illustrates a plan view of the guide movement path
and pickup movement path in the ninth embodiment of the present
invention;
[0064] FIG. 38 shows a relationship between a position on the guide
movement path and a position on the pickup movement path with
respect to the disk rotation speed; and
[0065] FIG. 39 illustrates a measurement result on surface
vibration measured on the device shown in FIG. 33.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0066] As shown in FIG. 1, in an optical information
recording/reproducing device in a first embodiment of the present
invention, a sheet-like optical disk 1 has a flexibility, a spindle
shaft 2 holds a hub 3 of the optical disk 1, a spindle motor 4
carries out rotation drive of the spindle shaft 2, an optical
pickup 6 writes/reads information onto/from the optical disk 1, a
positioning mechanism 7 for the pickup moves the optical pickup 6
along the radius direction of the optical disk 1, and a
stabilization guide member 8 is provided on the opposite side from
the optical pickup with respect to the optical disk 1, and prevents
surface vibration of the optical disk 1. A positioning mechanism 9
moves the stabilization guide member 8 together with the optical
pickup 6 along the radius direction of the optical disk 1. These
respective members/components are held by a device body 10.
[0067] FIGS. 2A and 2B illustrate a recording unit and a
reproducing unit both of which the above-mentioned optical pickup 6
acts. As shown in FIG. 2A, in the recording unit, a signal
processing circuit 11 performs a digital signal processing, signal
compression processing, etc. onto an input record signal as shown
in FIG. 2A. A laser drive control circuit 12 generates a laser
drive control signal based on the output from the signal processing
circuit 11. A laser drive part 13 drives a laser light source 14
including a semiconductor laser etc. in response to the output from
the laser drive control circuit 12. The laser light La of high
emission energy emitted from the laser light source 14 is condensed
by an object lens 15 of the optical pickup 6 shown in FIG. 1, the
record surface of the optical disk 1 is irradiated by an optical
spot (laser spot) thereof, and information recording by bit
formation is performed thereby onto the optical disk 1.
[0068] As the reproducing unit, the optical pickup 6 includes a
photoelectric conversion device 17 of a photodiode of the like, and
a reproduction signal processing circuit 18, etc, as shown in FIG.
2B. Thereby, emission of laser light at low energy from the laser
light source 14 is applied to record bits formed in the record
surface of the optical disk 1, the reflected light Lb therefrom is
input to the photoelectric conversion device through the object
lens 15. Then, signal decompression processing etc. is performed on
the output from the photoelectric conversion device 17 in the
reproduction signal processing circuit 18, and thus, a reproduction
signal is generated accordingly.
[0069] As shown in FIG. 3, the optical disk 1 in the sectional view
of the figure includes a record layer 20 facing the object lens 15
of the optical pickup 6, and a substrate 21 facing the
stabilization guide member 8, in a condition in which the disk 1 is
set onto a chucking part of the spindle shaft 2.
[0070] An example of the optical disk 1 in the first embodiment
will now be described in detail. In order to give flexibility in
the substrate, approximately 0.1 mm of thin sheet is used. For
example, grooves having a pitch of stamper of 0.6 micrometers and a
width of 0.3 micrometers are transferred by heat transfer onto a
sheet with a thickness of 80 micrometers made of polyethilene
telefthalate, and then, through sputtering, a sheet/Ag reflective
layer is formed thereon by films of 120
nm/(ZrO.sub.2Y.sub.2O.sub.3)--SiO.sub.2, 7 nm/AgInSbTeGe, 10
nm/ZnS--SiO.sub.2, and 25 nm/Si.sub.3N.sub.4 Membranes formed in
the stated order. Then, on this sheet, UV resin is coated through
spin-coating, and then is set by ultraviolet-ray application so
that a transparent protection film of 5 micrometers is formed.
Further, as a result of a large diameter of laser beam being
applied onto the record layer of the thus-produced disk, the record
layer is melted and crystallized. As a result, the reflectance
thereof is improved.
[0071] Surface vibration stabilization of the sheet-like optical
disk which has flexibility according to the first embodiment of the
present invention will now be described with reference to FIG. 4.
At a time of recording/reproduction, the optical disk 1 which has
flexibility of the above-mentioned configuration is rotated between
the optical pickup 6 and stabilization guide member 8. The rotating
optical disk 1, in itself, though it is small, has rigidity, and a
force occurs therein by which the disk 1 becomes a straight/plane
state by the action of centrifugal force (referred to as a disk
self-stretching force, hereinafter). Therefore, by causing the
stabilization guide member 8 to approach the optical disk 1, a
repulsive force is generated due to pressure difference of air flow
according to Bernoulli's law, and, surface vibration or axial
runout (along the direction of disk rotation axis) on the optical
disk 1 can be effectively reduced as a result of the
above-mentioned disk self-stretching force and the repulsive force
given by the stabilization guide member 8 being applied to the disk
1 with a good balance therebetween.
[0072] According to the first embodiment, the entire surface of the
record layer 20 of the optical disk 1 is not made to be faced by
the stabilization guide member 8. For example, as shown in FIG. 4,
a pillar-like stabilization guide member 8 whose end facing the
optical disk 1 has a longitudinal sectional shape of an arc.
Thereby, onto portions B and C on the upstream side and downstream
side of a portion A on which the stabilization from surface
vibration of disk is applied by the stabilization guide member 8
through the above-mentioned air force, this air force generated by
the stabilization guide member 8 is prevented from being applied.
Accordingly, repulsive force otherwise occurring in the disk 1 can
be effectively reduced on the portion A as the repulsive force can
be absorbed by the portions B and C instead. Thus, the portions B
and C in the peripheries of the relevant portion A act as "escape".
By this ingenuity, the effect of the stabilization by air force
increase at the portion A.
[0073] Furthermore, the stabilization guide member 8 faces the
optical disk 1 on the side of the substrate 21 opposite to the side
of the record layer 20 onto which the light La and Lb for
recording/reproduction is applied, and thus, recording/reproduction
is performed on the optical disk 1. Accordingly, even if the
stabilization guide member 8 slides on the optical disk 1, the
record layer 20 is free from being damaged thereby, and, thus, does
not occur recording/reproducing error. Moreover, the optical disk 1
usually bends in a manner of convex on the record layer 20 side.
This is because the sputter film has compression stress in the
record layer 20. For this reason, by applying the stabilization
guide member 8 to the optical disk 1 in a manner of pressing from
the side of substrate 21, adhering force between the stabilization
guide member 8 and optical disk 1 can be effectively stabilized,
and, thereby, the surface vibration on the optical disk 1 can be
effectively eliminated.
[0074] Moreover, the light La and Lb for recording/reproduction is
applied directly onto the opposite side of the optical disk 1 from
the side onto which the surface vibration stabilization function is
applied by the stabilization guide member 8. Accordingly, even when
the optical disk 1 is damaged as a result of the stabilization
guide member 8 touching the optical disk 1, this damage does not
reach the record layer 20 and thus, does not cause
recording/reproducing error. Further, since the light La and Lb for
recording/reproducing does not pass through the substrate 21, the
light La and Lb are free from influence of damage of the substrate
21 and also are free from optical property of the substrate 21.
Therefore, the substrate 21 may be opaque.
[0075] With reference to FIG. 4, further specific description will
now be made. In the configuration shown in FIG. 4, a setting should
be made such that, other than the stabilization guide member 8,
parts/components/members of the optical disk drive, device body, or
a disk cartridge in case the disk 1 is contained in the cartridge,
are apart from the optical disk 1 more than 1 mm so that these
parts/components/members are prevented from causing action
according to Bernoulli's law. However, since the operation distance
is short in case the object lens 15 has high NA, exceptionally, the
object lens 15 approaches to the distance on the order of 0.05 mm
through 0.3 mm.
[0076] Furthermore, FIG. 5 shows an experimental result of
measurement of actual surface vibration of the optical disk in the
configuration of FIG. 4 for two rotations. In this experiment, the
stabilization guide member 8 has the curvature radius of 50 mm at
the tip thereof and the diameter of 20 mm. The optical disk 1 has a
slot for tracking of 0.65-micrometer pitch formed into a
80-micrometer PET (polyethylene telefthalate) sheet; the record
film formed thereon through sputtering, and has the diameter of 120
mm, was rotated at 2000 rpm. The surface vibration was measured by
a laser displacement measurement unit. The set distance between the
stabilization guide member 8 and the optical disk 1 was
approximately 5 micrometers. There was no unusual vibration in the
member 8 and any sliding crack was not generated in the optical
disk 1. Accordingly, it can be seen that neither excess floating
nor sliding occurred. Further, disk surface vibration measured was
approximately 3 micrometers, and it can be seen that it is very
small, considering that a usual rigid disk produces surface
vibration of 50 micrometers or more.
[0077] Furthermore, Table 1 summarizes an experimental result on
surface vibration which was made through ten revolutions of the
same conditions described with reference to FIG. 5, and comparison
was made between the present embodiment and related art in which a
stabilization guide member is provided for the entire surface of
the disk: TABLE-US-00001 TABLE 1 TYPE OF WIDTH OF SURFACE VARIATION
OF STABILIZATION VIBRATION SURFACE VIBRATION GUIDE MEMBER
(MICROMETERS) (3.sigma., MICROMETERS) FIRST 11 2 EMBODIMENT RELATED
ART 20 6
[0078] As can be seen from the Table 1, according to the present
embodiment, satisfactory performance of stabilization from surface
vibration was obtained.
[0079] Such satisfactory stabilization performance from surface
vibration is obtained either in case where the stabilization guide
member 8 is provided in the device body (see FIG. 1 or 11) or in
case where the same member is provided in the disk cartridge (see
FIG. 12).
[0080] Further, experimentally, recording/reproducing was performed
in condition where the disk drive has the wavelength of 405 nm, and
the optical pickup has the NA of 0.9. In example, the record
position on the optical disk was at the radius of 45 mm, and the
shortest record bit length was 0.12 micrometers, and random digital
data was modulated according to 1-7RLL and was recorded there.
[0081] Further, record line speed was 10 m/s, and three-level
modulation was applied such that record peak power was 5 mW, erase
power was 2.6 mW and record bottom power was 0.1 mW. Then, the
resulting jitter between the basic clock signal and record signal
was less than 8%. Further, no particular turbulence on envelope of
the record signal occurred, and, also, stable focus and tracking
servo control was performed. Although residual error on focus
occurred in either recording or reproducing, the defocus value fell
within .+-.0.12 micrometers. In 0.8 or more high NA, the defocus
margin is very narrow, i.e., smaller than in case of DVD by a
factor of several times. Accordingly, it is necessary to control
the defocus amount to fall within .+-.0.2 micrometers or less. In
this meaning, it can be said that sufficient focus stabilization
could be achieved according to the first embodiment of the present
invention.
[0082] Moreover, evaluation was made on defocus amount also for a
case where the record line speed was increased into 20 m/s. Also in
this case, the defocus amount fell within .+-.0.12 micrometers or
less. On the conventional high rigidity disk, when line speed is
increased, surface vibration increases due to resonance phenomenon
or so, and, thus, defocus amount also increases. In contrast
thereto, according to the first embodiment of the present
invention, as mentioned above, superior result was obtained. This
is because stabilization from surface vibration is achieved by air
force according to the embodiment of the present invention, and,
thus, stabilization effect increases as the record line speed
increases.
[0083] In the present embodiment, in order to obtain the air force
stabilization effect effectively, it is necessary to take into
consideration the timing of operation on each component. Operation
at a time of the recording/reproduction according to the present
embodiment will now be described with reference to a flow chart
shown in FIG. 6.
[0084] Namely, the spindle motor 4 starts, rotates the optical disk
1 (in a step S1), which then reaches a predetermined rotation
speed, when a start signal is input into a central processing
circuit of the device according to the present embodiment not shown
(YES in a step S2), and thereby, the stabilization guide member 8
is moved into a predetermined approach position to the optical disk
1 (in a step S3). There, a laser displacement measurement unit or
the like is used for measuring surface vibration of the disk 1,
and, thereby, when the surface vibration measured falls within a
predetermined surface vibration stabilized range (YES of a step
S4), the optical pickup 6 is moved to a predetermined approach
position with respect to the optical disk 1 (in a step S5), and
recording/reproduction is started at this time (in a step S6).
[0085] Then, the stabilization-guide member 8 is moved by the
positioning mechanism 9, while the optical pickup 6 is moved by the
positioning mechanism 7, in an interlocking manner. Thus, the
optical pickup 6 and stabilization guide member 8 are made to move
together along a radius direction of the optical disk 1 so that
they face one another at any time via the optical disk 1 (in a step
S7). Then, this operation continues until the
recording/reproduction on all relevant signals are completed (in a
step S8)
[0086] Although the configuration shown in FIG. 4 is a basic one,
it is possible to further improve the surface vibration
stabilization effect by configuring the stabilization guide member
8 as shown in FIG. 7. In the configuration shown in FIG. 7, a side
from which the optical disk 1 moves is set as a positive pressure
generating part 25a having a convex form in the stabilization guide
member 25. Thereby, air is compressed between the positive pressure
generation part 25a and optical disk 1, and, thus, repulsive force
occurs therebetween. Furthermore, a side toward which the optical
disk 1 moves is set as a negative pressure generating part 25b
having a concave shape conversely. Thereby, the air which flows by
this negative pressure generating part 25b expands rapidly and
thus, a negative pressure occurs as compared with the atmospheric
pressure, and, thus, attraction force occurs between the
stabilization guide member 25 and optical disk 1.
[0087] Thus, simply through balance between the repulsive force and
attracting force thus generated according to Bernoulli's law due to
difference in air pressure between the stabilization guide member
25 and optical disk 1, the surface vibration on the optical disk
can be eliminated, and stabilization is achieved.
[0088] Furthermore, it is possible to widen the surface vibration
stabilized area by providing a flat part 25c between the positive
pressure generating part 25a and negative pressure generating part
25b in the stabilization guide member 25, as shown in FIG. 7.
[0089] Thus, by the stabilization guide member 8 (25), both the
repulsive and attraction forces are generated, and through this
action, the distance between the optical disk 1 and stabilization
guide member 25 can be stabilized.
[0090] In addition, the stabilization guide member 8 (25) may be
set up suitable to the particular design/specification of the
optical disk 1 or the drive device, and a surface vibration stable
state on the optical disk 1 adapted therefor can be set, by
providing the stabilization guide members 8 at a plurality of
positions each facing the optical disk 1 along the circumferential
direction of the disk 1, as shown in FIG. 8.
[0091] According to the present embodiment, the optical disk 1 must
have flexibility softly inevitably since eliminating the surface
vibration or tilt is achieved by the air force. As a result, on
areas for which no stabilization guide member is provided, the
optical disk 1 may then have large surface vibration compared with
a case of applying a normal disk material as in a CD, and the
surface vibration on the order of 0.5 mm is easily generated there.
Depending on each particular case, it is difficult to cause this
surface vibration to fall within 5 micrometers or less by the
stabilization guide member neighboring the optical pickup 6 within
a very short time period.
[0092] Then, in the present embodiment, as shown in FIGS. 8 through
10, the margin of the disk drive device system design can be
improved by further providing a plurality of stabilization guide
members 8b along the circumferential direction of the optical
pickup 6, but apart from the neighborhood of the optical pickup 6.
Thereby, while roughly stabilizing the entire disk 1 by means of
these additional stabilization guide members 8b, further
stabilization is performed on a main area (near the optical pickup
6) by means of the main stabilization guide member 8a, as shown in
FIG. 8.
[0093] As shown in FIG. 8, for example, the (main) stabilization
guide member 8a is provided so as to face the optical pickup 6,
while the (sub) stabilization guide members 8b are provided apart
from the optical pickup 6 for rough stabilization. On these
sub-stabilization members 8b, since what is necessary is just to
eliminate large surface vibration on the order of 0.5 mm, a merely
simple convex spherical shape should be provided thereon. Rather,
for these sub-stabilization guide members 8b, it is required to
prevent sliding on the disk surface. This is because it is more
desirable not to cause an unnecessary vibration by sliding. For
this reason, the sub-stabilization guide members 8b should
preferably have large sizes in comparison to the main stabilization
guide member 8a so as to generate larger floating force.
[0094] For example, as shown in FIG. 9, the main stabilization
guide member 8a has a pillar shape of a diameter D (=approximately
10 mm) while the sub-stabilization guide member 8b has a pillar
shape of a diameter D of 20 mm. Thereby, the sub-stabilization
guide member 8b generates larger floating force. In fact, in case
the projecting end of the stabilization guide member 8 has a
spherical shape, the floating force applied onto the disk 1 thereby
becomes larger as the area of the guide member 8 facing the disk
surface becomes larger.
[0095] Alternatively, or in addition, as shown in FIG. 10, the
distances L1 and L2 of the main and sub-stabilization guide members
8a and 8b from a disk reference setting plane (horizontal plane
crossing a chucking position between the hub 3 of the optical disk
1 and spindle shaft 2) are set such that L2>L1. Thereby, it is
possible to effectively reduce the possibility of the
sub-stabilization guide member 8b contacting/colliding the disk
surface of the disk 1.
[0096] The positions and number of these sub-stabilization guide
members may be appropriately determined according to a particular
design of the disk drive device applied.
[0097] According to the first embodiment of the present invention,
the stabilization guide member 8 and the positioning mechanism 9
therefor are provided in the upper part in the main part 10 of the
disk drive device, as shown in FIG. 1. Therefore, a user can deal
with the optical disk 1 in the state of nakedness without a
cartridge. In this case, the optical disk 1 can be made as a
low-cost optical information recording medium. In fact, in the
present embodiment, the optical disk 1 has a sheet structure, and,
is handled by putting in an envelope or so, and, in case of loading
it in the drive device, a user picks up it therefrom and set it
onto the spindle shaft 2
[0098] FIG. 11 shows a side-elevational sectional view of an
optical information recording/reproducing device in a second
embodiment of the present invention. In this configuration, the
sheet of optical disk 1 is contained in a disk cartridge 27 having
opening windows 26 and 26, this disk cartridge 27 is inserted into
a predetermined position in the recording/reproducing device,
shutters 28 and 28 are then opened by an operation unit not shown,
the stabilization guide member 8 and optical pickup 6 are moved so
that this member 8 and the optical pickup 6 are inserted
therethrough, and thus, a state in which recording/reproduction is
possible is created, as shown in FIG. 11.
[0099] As the disk cartridge 27, a common configuration can be
employed, and, thus, it can be provided with a very low cost rise
if any.
[0100] FIG. 12 shows a side-elevational sectional view of an
optical information recording/reproducing device in a third
embodiment of the present invention. In this configuration, the
stabilization guide member 30 is provided in the inside of the disk
cartridge 31. As shown in FIG. 13, the stabilization guide member
30 has an oblong form long along a radius direction of the optical
disk 1, and no positioning mechanism 9 is needed different from the
first and second embodiments. This stabilization guide member 30
provides the surface vibration stabilization effect on the optical
disk 1 as in the above-described first embodiment of the present
invention. The stabilization guide member 30 is positioned so that
an area on which the surface vibration stabilization effect
functions is located at a position at which the optical pickup 6
applies the laser beam (recording/reproducing light).
[0101] Also in the third embodiment, a shutter 28 is moved by an
operation unit not shown, so that the optical pickup 6 may be
inserted through an opening window 26 opened widely thereby, and,
thus, a state in which recording/reproduction is possible is
created, as shown in FIG. 12.
[0102] According to the third embodiment, as the stabilization
guide member 30 is built in the disk cartridge 30, the entire
configuration of the recording/reproducing device can be made same
as the conventional device for applying an optical disk of a rigid
substrate. Thereby, it becomes easy to take compatibility with a
disk drive system of the optical disk using such a rigid
substrate.
[0103] FIG. 14 shows a plan view of a disk cartridge in a
fourteenth embodiment of the present invention and FIG. 15 shows a
side-elevational sectional view thereof taken along an A-A line
shown in FIG. 14. This disk cartridge may be applied to an optical
recording/reproducing device same as the first embodiment described
above.
[0104] As shown in FIG. 14 and FIG. 15, in the disk cartridge 33, a
plurality of optical disks 1 each of the shape of a sheet which has
flexibility can be held, and has a configuration which can be used
with an automatic disk replacement mechanism. In this
configuration, as the number of sheets of the optical disks 1 is
increased, the storage capacity usable can be thus increased
accordingly. According to the first embodiment of the present
invention, as the stabilization guide member is provided in the
recording/reproducing device for eliminating/stabilizing the
surface vibration of the optical disk 1 at a portion thereof on
which a laser beam from the optical pickup 6 is applied, it is
possible to reduce the thickness of the optical disk 1.
Accordingly, even when the number of optical disks 1 held by the
disk cartridge 33 increases, the whole disk cartridge 33 volume
does not become much larger.
[0105] The disk cartridge 33 of the present embodiment has a
configuration such that the end part of each optical disk 1 is
inserted into a disk tray 34 for holding the optical disk 1
therewith, and the automatic disk replacement operation is
performed by taking the disk tray 34 in and out of the
record/reproducing device.
[0106] In order to identify and take out a specific optical disk 1
from among the plurality of disks 1, each disk tray 35 has an
identification part 35 at a position different from each other.
Thereby, these different positions are detected by the automatic
disk replacement mechanism provided on the recording/reproducing
device, and, thus, a desired optical disk 1 can be taken out from
the disk cartridge 33, and is loaded into the recording/reproducing
device.
[0107] Specifically, as each disk 1 is thin, and intervals between
the respective disks 1 are narrow, it may be difficult for the
automatic disk replacement mechanism to identify particular disks.
Accordingly, in the fourth embodiment, as shown in FIG. 14, the
disk identification-parts 35 are arranged `laterally`. Then, an arm
of the disk replacement mechanism (not shown) is configured such as
to be inserted into a hole formed in each identification part 35,
and is taken out. As the lateral length of the disk cartridge 33 is
relatively large, the identification can be easily made.
[0108] According to the fourth embodiment, the disk cartridge 33
has a configuration such that simply the disk trays 34 are placed
on each other, and, thus, has a simple configuration. Furthermore
it is possible to provide a disk cartridge having a large
information storage capacity by a small size. Further, as the
flexible disks 1 each being thin, having low rigidity and, thus,
hard to handle alone, are held by the cartridge 33, they can be
easily handled by a user.
[0109] Although description has been made on the rewritten type
optical disk which employs the phase-change record layer, the
present invention described above may also be applied to another
type of disk recording medium. In fact, according to the present
invention described above, a configuration of a guide member for
effectively eliminating/stabilizing surface vibration of a disk
recording medium and improving recording accuracy thereon is
provided, and also, application of this configuration to a
recording/reproducing device can be made. For example, the present
invention may be applied to a reproducible optical disk using
embossing pits, an optical magnetism type or magneto-optical record
disk, and another any type of disk recording medium for which
recording/reproducing is performed through a laser beam applied
thereto.
[0110] Moreover, on the stabilization guide member according to the
present invention, various forms and structures can be considered,
for example, as shown in FIGS. 16A through 21. Each of the
stabilization guide members 40 and 41 shown in FIGS. 16A and 16B
has a configuration same as that described above with reference to
FIG. 7, and includes a first guide surface 40a/41a of a convex
form; a second guide surface 40b/41b having a concave from; and a
flat surface 40c/41c. The stabilization guide member 40 shown in
FIG. 16A extends along a line along a radius direction of the
optical disk 1 along which the optical pickup 6 moves. The
stabilization guide member 41 shown in FIG. 16B is movable along
the line along the radius direction of the optical disk 1 along
which the optical pickup 6 moves.
[0111] In each of the stabilization guide members 40 and 41, the
flat surface 40c/41c may be omitted, and, thus, only the first and
second guide surfaces 40a/41a and 40b/41b may be provided
adjacently.
[0112] Each of the stabilization guide members 42 and 43 shown in
FIG. 17 and FIGS. 18A, 18B has a surface formation including, in
the order from the upstream side of disk rotation direction, a
first guide surface 42a/43a of a convex form, a flat surface
42c/43c, and a second guide surface 42b/43b of also a convex form.
The stabilization guide member 42 shown in FIG. 18A extends along a
line along a radius direction of the optical disk 1 along which the
optical pickup 6 moves. The stabilization guide member 43 shown in
FIG. 18B is movable along the line along the radius direction of
the optical disk 1 along which the optical pickup 6 moves.
[0113] In each of the stabilization guide members 42 and 43, the
flat surface 42c/43c may be omitted, and, thus, only the first and
second guide surfaces 42a/43a and 42b/43b may be provided
adjacently.
[0114] The stabilization guide member 44 shown in FIGS. 19 and 20
has a surface formation including, in the order from the upstream
side of disk rotation direction, a first guide surface 44a having a
convex form and a curved surface along a direction perpendicular to
the disk rotation direction, a flat surface 44c having a curved
surface along the direction perpendicular to the disk rotation
direction, and a second guide surface 44b of also a convex form and
having a curved surface along the direction perpendicular to the
disk rotation direction. The stabilization guide member 44 is
provided movably along the line along the radius direction of the
optical disk 1 along which the optical pickup 6 moves.
[0115] In the stabilization guide member 44, the flat surface 44c
may be omitted, and, thus, only the first and second guide surfaces
44a and 44b may be provided adjacently.
[0116] The stabilization guide member 45 shown in FIG. 21 has a
basically pillar-like shape and, same as that shown in FIG. 4, has
a surface formation of a curved surface 45a at an end facing the
optical disk 1.
[0117] In each configuration, as the surface of the stabilization
guide member thus has an arc-shaped, the Bernoulli's effect can be
smoothly created with the disk surface.
[0118] Thus, according to the first through fourth embodiments of
the present invention, the stabilization guide member has a
configuration such as to perform the following functions on the
flexible disk being rotated: That is, on the upstream side along
the disk rotation direction, the stabilization guide member
generates a positive pressure, thereby, repulsive force being
generated between the flexible disk and stabilization guide member.
As a result, the flexible disk floats from the stabilization guide
member. In contrast thereto, on the downstream side along the disk
rotation direction, the stabilization guide member generates a
negative pressure, thereby, attraction force being generated
between the flexible disk and stabilization guide member. However,
as the flexible disk has a somewhat rigidity, it does not come into
contact with the stabilization guide member but merely somewhat
approaches the stabilization guide member.
[0119] Thus, the flexible disk is subjected to the repulsive force
and after that, is subjected to the attraction force from the
stabilization guide member. Accordingly, the flexible disk rotates
while the flexible disk has a fixed distance with the stabilization
guide member stably at a position at which the stabilization guide
member faces the flexible disk. Accordingly, by applying a laser
beam at the position of the flexible disk for performing
recording/reproducing, it is possible to perform
recording/reproducing in a condition free from or with effectively
reduced surface vibration and tilt of the flexible disk.
[0120] Thus, by employing the air force to perform surface
vibration elimination/stabilization, and also, by configuring the
flexible disk having a low rigidity, it is possible to create
stable recording/reproducing conditions without problematic surface
vibration, without needing to configure the flexible disk at high
accuracy. Accordingly, the recording/reproducing pickup should not
have a performance of coping with large surface vibration of the
flexible disk, thus, the defocus amount is reduced, and
high-density recording can be achieved.
[0121] Furthermore, thereby, the object-lens actuator of this
pickup should not cope with a large amplitude, low frequency
movement, and instead, should have a high-rigidity elastic member
(spring) for supporting the actuator. Thereby, the pickup has a
high-band resolution at a high-frequency band, and, thus, it can
well control defocus even in case of high-line-speed
recording/reproducing.
[0122] Furthermore, the escape portions are provided in the
flexible disk in which the above-mentioned air force according to
BernQulli's law is not applied on the upstream and downstream sides
of position at which the air force is applied for eliminating
surface vibration so as to stabilize. Thus while the flexible disk
is forcibly deformed by the stabilization guide member so as to
create the portion of the flexible disk at which the flexible disk
falls in a stable condition, it is possible to effectively reduce
repulsive force at the stabilized portion there by providing the
escape portions at which the flexible disk is allowed to be
unstable instead.
[0123] In contrast thereto, according to the related art, a
stabilization plate is provided so as to face the entire surface of
a flexible disk. However, according to such a device, when the
flexible disk bends, bending force strongly functions from the
upstream and downstream sides, and, thereby, it may be difficult to
create a stabilized condition at a portion at which a laser beam
for recording/reproducing is applied.
[0124] Furthermore, on a type of optical disk on which a record
layer is formed on a flexible substrate, the substrate is likely to
curve toward the direction opposite to the layer formed side. Then,
by providing the stabilization guide member according to the
present invention on the side opposite to the record layer formed
side, the stabilization effect effectively functions by the
restoration force of the substrate itself and the repulsive force
from the stabilization guide member. For this reason, according to
the above-mentioned embodiments of the present invention, the
stabilization guide member is disposed on the side opposite to the
record layer formed side, i.e., the substrate side of the optical
disk, while the optical pickup is disposed on the record layer
formed side. Accordingly, even when the optical disk is damaged as
a result of the stabilization guide member touching the optical
disk, this damage does not reach the record layer and thus, does
not cause recording/reproducing error. Further, since the laser
beam for recording/reproducing does not pass through the substrate,
the laser beam is free from influence of damage of the substrate
and also are free from optical property of the substrate.
[0125] Furthermore, the present invention described above may be
applied to a disk derive device having single recording function,
or a disk drive device having a single reproducing function, or any
other drive device handling a flexible disk.
[0126] A fifth embodiment of the present invention will now be
described.
[0127] FIG. 22 shows an outline configuration view of an
information recording/reproducing device in the fifth embodiment of
the present invention; FIG. 23 shows an outline in the neighborhood
of a guide member 104 viewed from a radius direction of an optical
disk 101 of the recording/reproducing device shown in FIG. 22; and
FIG. 24 shows an example of a sectional view of the sheet-like
record disk 101 which has a flexibility on which
recording/reproduction is performed by the information
recording/reproducing device shown in FIG. 22. For the purpose of
convenience in illustration, the thickness of the sheet-like record
disk is magnified more than an actual size in FIGS. 22 through
24.
[0128] In the information recording/reproducing device which is an
optical recording/reproducing device shown in FIG. 22, a spindle
107a holding a hub (not shown) of the sheet-like record disk 101
which is a disk-like recording medium which has flexibility; a
spindle motor 107 performing rotation drive of the spindle 107a; on
a side of the sheet-like record disk 101, an optical pickup 102
which is an optical head mechanism which is arranged in this
embodiment at the bottom thereof, condenses a laser beam onto a
TbFeCo magneto-optical recording layer 101e which is provided on a
record side of the sheet-like record disk 101, and carries out
recording/reproduction operation.
[0129] A move rail 103 supports the optical pickup 102, and the
guide member 104 is arranged with in the present embodiment at the
bottom thereof, and controls positional deviation such as the
above-mentioned surface vibration of the sheet-like record disk 101
on the other side of the sheet-like record disk 101. A guide
actuator 105 is a mechanism of adjusting a projection amount of the
guide member 104 with respect to the sheet-like record disk
101.
[0130] The hub fixed onto the sheet-like record disk 101 for
chucking is omitted from the figures.
[0131] The above-mentioned guide actuator 105 is attached in a
chassis 106. Although a piezo-actuator is employed as the guide
actuator 105 in the present embodiment, instead thereof, an
electromagnetic actuator such as a linear motor may be
employed.
[0132] As shown in FIG. 23, in using the magneto-optical sheet-like
record disk 101 as in the present embodiment, the (stabilization)
guide member 104 includes an electromagnet 104a for making a
magnetic field at a time of information
recording/erasing-operation. This electromagnet 104a can reverse
the N/S pole of the TbFeCo magneto-optical recording layer 101e,
according to recording/erasing operation.
[0133] As shown in FIG. 24, as the above-mentioned sheet-like
record disk 101 in the fifth embodiment, a magneto-optical
sheet-like record disk is used. The sectional structure of this
sheet-like record disk 101 includes a sliding-protection film 101a
such as DLC (diamond-like carbon) of 200 nm thickness formed on one
side of a base member 10b; an Ag reflective layer 101c formed on
the other side of the base member 10b; a SiNx protection layer 101d
formed on the Ag reflective layer 101c; a TbFeCo magneto-optical
record layer 101e formed on the SiNx protection layer 101d; a SiNx
projection layer 101f formed on the TbFeCo magneto-optical record
layer 101e; and a transparent protection layer 101g made of an
ultraviolet setting resin or the like of 5 micrometers thickness
formed on the SiNx protection layer 101f.
[0134] The base member 101b is produced by the following process: A
sheet of 0.1 mm thickness in a product made from dry photograph
polymer is used, then, a stamper having pits and grooves formed
thereon is pressed thereon, then, the stamper is removed therefrom,
and, after that, ultraviolet ray irradiation is performed. Thus,
the pits and grooves are formed thereon. Then, the outer diameter
of 120 mm of disk is obtained therefrom, and, then, a hole of inner
diameter of 10 mm is formed therein.
[0135] The thickness of the base member 101b should be
approximately within a range between 0.01 and 1.5 mm, and more
preferably, within a range between 0.03 and 0.2 mm. When it is too
thick, a properly flexibility cannot be provided, while when it is
too thin, the sheet-like record disk 101 may be destroyed due to
stress applied in acceleration/deceleration thereof.
[0136] The record film is formed on this base member 101b through
sputtering. Specifically, the Ag reflective layer 101c is first
formed by 50 nm thickness, then, the SiNx protection layer 101d is
formed by 8 nm thickness thereon, the TbFeCo magneto-optical
recording layer 101e is formed by 15 nm thickness thereon, and the
SiNx protection layer 101f is formed by 40 nm thickness thereon.
The number `x` of SiNx may be determined arbitrarily. That is,
since a shift may be made from the stoichiometric composition
according to the film forming requirements, it is expressed as
`x`.
[0137] In case of the magneto-optical medium, since magnetic field
is required at a time of recording operation, the electromagnet
104a is provided in the guide member 104. The magneto-optical
medium has a signal intensity smaller than that of a phase-change
medium, and thus, it is strongly influenced by polarizational noise
of a plastic substrate. However, since actual
recording/reproduction is carried out without causing laser beam to
pass through the base member 10b, such a problem does not
occur.
[0138] Further, a permanent magnet may be provided in the guide
member 104 instead of the electromagnet, a drive mechanism for the
permanent magnet may be provided, and thereby, N/S may be reversed.
However, in viewpoint of addressing to a simpler structure,
providing of the electromagnet 104a is still preferable.
[0139] Moreover, it is necessary to reduce the record density
because of the smaller signal, since the record speed is very high
because of the magnetic record type. For this reason, the
magneto-optical recording layer is employed in the fifth
embodiment. In fact, as for this type of record layer, the record
line speed on 1 m/s or 30 m/s can be achieved. Therefore, it is
possible to keep rotating of the sheet-like record disk 101 at more
than 15 m/s by which the sheet-like record disk 101 can float by
means of air flow occurring thereby.
[0140] On the SiNx protection layer 101f, ultraviolet setting resin
is coated by spin coating, and, then, is made to set, and, thus,
the 5-micrometer transparent protection layer 101g is formed.
Finally, the hub for chucking is fixed at the center of the disk,
and, thus, the flexible optical disk which is the sheet-like record
disk 101 is obtained.
[0141] On the side of the sheet-like record disk 1 facing the guide
member 104, 20 nm of DLC (diamond-like carbon) is formed by
sputtering.
[0142] As mentioned above, recording/reproduction operation is not
performed by causing the laser beam to pass through the basic
member 101b, but recording/reproduction operation is carried out
through the transparent protection layer 101g which is ultraviolet
setting resin. Therefore, a material opaque can be used as the base
member 101b.
[0143] The optical recording/reproducing device according to the
fifth embodiment of the present invention uses a semiconductor
laser with a wavelength of 405 nm not shown, and is of NA of 0.85.
The optical pickup 102 condenses the laser beam by an object lens
102a. The distance between the record film of the sheet-like record
disk 1 and the object lens 102a is approximately 0.2 mm.
[0144] The sheet-like record disk 101 is chucked onto the spindle
107a, and the metal guide member 104 is provided on the side
opposite to the side of the object lens 102a with respect to the
sheet-like record disk 101. Since the sheet-like record disk 101 is
soft, the periphery thereof slightly lowers by gravity.
Accordingly, the sheet-like record disk 101 does not touch the
guide member 104 immediately after the chucking.
[0145] When the sheet-like record disk 101 rotates and regular
rotation is reached by driven by the spindle motor, due to the
centrifugal force, the disk 101 becomes in general flat and thus,
touches the guide member 104. However, they are not completely in
contact as air flow generated therebetween due to the rotation of
the sheet-like record disk 101. Then, the optical pickup 102
approaches the sheet-like record disk 101, and performs
recording/reproduction thereon. When the line speed of the disk 101
with respect to the optical pickup 102 reaches approximately 5 m/s,
the disk 101 floats completely from the guide member 104 by the air
flow. However, even when rotation speed of the disk 101 does not
reach a range causing such air floating, it is possible for the
guide member 104 to control the position of the sheet-like record
disk 101.
[0146] Since the guide member 104 is so long as to extend for a
moving range of the optical pickup 2, i.e., has a length more than
the radius of the sheet-like record disk 101, the optical pickup
102 and guide member 104 face one another through the disk 101.
Since the position along the focus direction of the sheet-like
record disk 101 is controlled by the guide member 104, there is
almost no surface-vibration of the sheet-like record disk 101.
Therefore, the moving range of the object lens 102a can be designed
smaller. That is, it becomes smaller remarkably from approximately
.+-.0.5 mm into approximately .+-.0.05 mm. Thereby, an actuator of
the object lens 102a may be made to have a lighter weight, and the
servo characteristic at a high frequency region can be improved.
This contributes to widen the line speed margin of the optical
pickup 102 in case of operation at high line speed. The length of
the guide member 10 may however be made shorter than the moving
range of the optical pickup 102.
[0147] Although not shown in the figures, this sheet-like record
disk 101 is usually held by a cartridge. When it is inserted into
the drive device, the disk 101 is pulled out therefrom, and is
chucked onto the spindle.
[0148] Moreover, the guide member 104 which controls the position
of the sheet-like record disk 101 as mentioned above has a
projecting end thereof shaped to be curved so as not to damage the
surface of the disk 101 in case of touching. The material of the
guide member 104 is Ti alloy. The surface of the guide member 104
is worked so that there is approximately 5-micrometer unevenness.
Thereby, sticking of the guide member 104 with the sheet-like
record disk 101 is avoided.
[0149] As shown in FIG. 23, in the guide member 104, the
electromagnet 104a is contained for recording/erasing, as mentioned
above. By this electromagnet 104a, N/S can be reversed according to
recording/erasing. The guide member 104 is fixed to the chassis 106
through the guide actuators 105 of piezo-actuators, as shows in
FIG. 22.
[0150] The guide member 104 projects by the guide actuators 105
which are slight movement mechanisms for this guide member 104, and
thereby, the projection amount of the guide member 104 is finely
adjusted. This adjustment on projection amount is made such that
the focus offset on the object lens 102a may become made smaller,
i.e., zero.
[0151] Moreover, abnormal vibration of the guide member 104 is
detected by monitoring of the impedance of these guide actuators
105.
[0152] While the rotation speed of the sheet-like record disk 101
is low, vibration caused by sliding of the guide member 104 on the
disk 101 occurs. Then, as the rotation speed increases and floating
of the disk 101 from the guide member 104 occurs, the amplitude of
vibration decreases. When abnormally large vibration is detected,
the guide member 104 is caused to be apart from the disk 101 by
means of the actuators 105, and, simultaneously, the optical pickup
102 is caused to retreat. Further, the spindle 107a is stopped
rotation, and the sheet-like record disk 1 is returned to the
cartridge, then, ejection of the cartridge is performed.
[0153] The above-mentioned abnormal vibration is vibration
occurring in the sheet-like record disk 101 during rotation, due to
temperature, humidity, and variation in the substrate thickness
etc., and, extremely large abnormal vibration is vibration
occurring at an earlier stage of collision between the sheet-like
record disk 101 and object lens 102a.
[0154] FIG. 25 is a block diagram of a servo control system except
a signal processing system of the information recording/reproducing
device shown in FIG. 22. The servo control system of this
information recording/reproducing device is the same as that of a
general optical disk drive almost, a portion positioning the guide
member 104 on the basis of focus offset, and a portion determining
vibration data on the guide member 104 and stopping the operation
of the drive device are added according to the present
embodiment.
[0155] This servo control system includes a focus servo unit 108
which receives a focus error signal, and performs focusing
operation for applying the laser beam onto the record surface of
the sheet-like record disk 101; a tracking servo unit 109 which
receives a tracking error signal and drives a slide motor 110 so
that the laser beam may follow the track of the sheet-like record
disk 101; a spindle servo unit 112 which controls uniformly the
rotation speed or line speed of the sheet-like record disk 101 by
PLL control etc.; a guide servo unit 111 which receives the focus
error signal and drives the guide member 104 so that the record
surface of the sheet-like record disk 101 may enter in the depth of
focus of the object lens 102a; a preamplifier matrix 113 which
provides the focus error signal to the focus servo unit 108 and
guide servo unit 109, and provides the tracking error signal to the
tracking servo unit 109; and a CPU 114 which controls the whole
device. The movement of the guide member 104 is stopped after a
height adjustment thereof is finished during the rotation of the
sheet-like record disk 101 basically. Projecting operation of the
guide member 104 is performed for eliminating the offset along the
focus direction while the servo operation of the focus servo unit
108 performs positional control of the object lens 102a so as to
follow dynamic surface vibration of the sheet-like record disk
101.
[0156] The above-mentioned focus servo unit 108 acts as a focal
servo system with the optical pickup 102, and provides a control
signal which drives the optical pickup 102 so that the distance
between the record surface of the sheet-like record disk 101 and
object lens 102a may be kept constant, to an actuator of the
optical pickup 102 based on the focus error signal input from the
preamplifier matrix 113.
[0157] The above-mentioned tracking servo unit 109 acts as a
tracking servo system with the optical pickup 102 and slide motor
110, and provides, to the slide motor 110, a control signal for
driving the optical pickup 2 so that the laser beam may follow the
track of the sheet-like record disk 1 based on the tracking error
signal input from the preamplifier matrix 113.
[0158] The above-mentioned guide servo unit 111 moves the guide
member 104, instead of moving the object lens 102a so as to cause
the record surface of the sheet-like record disk 101 to fall within
the depth of focus of the object lens 102a. In order to perform
this control operation, based on the focus error signal input from
the preamplifier matrix 113, the guide member 104 is moved so that
the DC offset of the signal may become minimum, and thus, the
record surface of the sheet-like record disk 101 is made to fall
within the depth of focus of object lens 102a.
[0159] The above-mentioned spindle servo unit 112 acts as a spindle
servo system with the spindle motor 107 and guide actuators 105,
and, based on the control signal from the CPU 114, controls the
rotation speed or line speed of the sheet-like record disk 101
uniformly by PLL control, etc.
[0160] The above-mentioned preamplifier matrix 113 generates the
focus error signal and tracking error signal from an electric
signal obtained from photoelectric conversion of reflective light
beam from the record surface of the sheet-like record disk 101
through the optical pickup 102.
[0161] The CPU 114 provides the control signal to the spindle servo
unit 112 for causing the rotation speed/line speed of the
sheet-like record disk 101 to be fixed to a predetermined speed;
provides to the guide servo unit 111 a projection amount control
signal when vibration of abnormal amplitude is detected on the
guide actuators 105; provides to the guide actuators 115 a guide
retreating control signal, also, provides a pickup retreating
signal to the actuator of optical pickup 102 and slide motor 110,
and further provides a stop control signal to the spindle motor 117
when vibration of further larger amplitude more than a
predetermined value is detected on the guide actuators 115.
[0162] As mentioned above, instead of moving the optical pickup
102a, the guide member 104 is moved so as to cause the record disk
101 falls within the depth of focus of the object lens 102a.
Specifically, the reflected light from the record disk 101 is
received by the optical pickup 102, and, therefrom, the focus error
signal is generated by the preamplifier matrix 113. Then, the guide
member 104 is moved so as to cause the DC offset of the focus error
signal becomes minimum. For this purpose, the CPU 114, based on the
S-curve of the focus error signal, controls the guide servo unit
111 so as to cause the guide member 108 so that the record surface
of the record disk 101 falls within the depth of focus of the
object lens 102a.
[0163] Further, the CPU 114 controls the guide actuators 105 by the
control signal so as to control the projection amount of the guide
member 104, when abnormal vibration is detected from a vibration
sensor, so as to cause the vibration to become smaller.
[0164] When a larger abnormal vibration than a predetermined level
is detected from the vibration sensor, the CPU 114 performs
controls such that the guide member 104 retreats, and also, the
optical pickup 102 retreats, and, also the spindle 107a stops
rotation.
[0165] Such a larger abnormal vibration may be a suddenly occurring
large pulse caused by collision of the sheet-like record disk and
guide member, for example. For example, it is a case where the
amplitude peak value of abnormal vibration more than 5 Hz exceeds
10 times of the stable state.
[0166] Moreover, the CPU 114 controls the positional deviation (or
axial runout) such as surface vibration of the record disk 101 with
respect to the optical pickup 102 by moving the projection amount
of the guide member 104. Then, after that, before the focus servo
control on the optical pickup 102 for converging the
recording/reproducing beam onto the record disk 101 is locked,
positioning of the guide member 104 is performed in a rough
adjustment of distance between the object lens 102a and disk record
surface, by changing the projection amount of the guide member 104
so as to examine the S-curve on the focus error signal obtained by
this change, instead of moving the object lens 102a.
[0167] The record disk 101 chucked onto the spindle 107a is rotated
thereby to the predetermined rotation speed. Then, after that, the
guide member 104 is moved to approach the disk record surface to a
first predetermined position. This position is such that it can be
expected that the record disk 101 can float. Then, the optical
pickup 102 is moved to a directory management area of the record
disk 101.
[0168] This first predetermined position is determined such that a
standard disk used as a design standard is used and this disk can
stably float. For example, this first predetermined position is a
position slightly lower than the surface of the disk 101. That is,
the state in which the guide member 104 little pushes the record
disk 101 is a stable state. At this time, the disk 1 bends as if a
bowl is reversed.
[0169] Then, first the so-called S-curve is obtained by slightly
changing the projection amount of the guide member 104 in a state
in which the focus servo control is stopped. Then, after that, the
focus servo control is started.
[0170] Generally, although the S-curve is obtained by adding a DC
offset to the object lens and height position adjustment is carried
out, the height adjustment is performed by controlling the
projecting amount of the guide member 104 according to the fifth
embodiment instead. Accordingly, the object lens 102a operates in a
state in which no DC offset exists. Further, as large surface
vibration on the record disk 101 is eliminated by the guide member
104, the actuator of the object lens 102a should not move over a
wide range, and, thus, the weight thereof can be effectively
reduced.
[0171] Then, the tracking servo unit 109 operates. Then, the
optical pickup 102 moves inward/outward according to read-out of
data, while the projection amount of the guide member 104 is
controlled by the guide actuators 105 so that the DC offset of the
focus servo unit 108 always becomes minimum. In this time,
vibration of the guide member 104 is monitored at any time. Then,
when a reference value is exceeded by the monitored vibration, the
projection amount of the guide member 104 is finely controlled.
Furthermore, when a threshold value is exceeded, the guide member
104 is made apart from the disk 101 immediately, then optical
pickup 102 is made retreat, and the spindle 107a is stopped
rotation.
[0172] Recording/reproduction of signal was carried out with this
sheet-like record disk 101 and information recording/reproducing
device according to the fifth embodiment as an experiment. The
experimental conditions are as follows:
[0173] Record Power: 4 mW;
[0174] Erase Power: 3.5 mw;
[0175] Reproduction Power: 0.2 mW;
[0176] Cannel Clock Frequency: 100 mHz;
[0177] Minimum Mark Length: 0.15 micrometers/bit;
[0178] Track Pitch: 0.32 micrometers
In the conditions, random data modulated by 1-7 modulation could be
recorded by land and groove recording, and could be reproduced.
This corresponds to the capacity of 18 GB. Furthermore, the
recording rate could be increased.
[0179] Since, in the magneto-optical type, a record mark is formed
by temperature distribution, much fine multi-pulse strategy is
unnecessary. For this reason, the number of pulse divisions can be
reduced in recording compared with a common multi-pulses used for a
CD-RW etc. For this reason, it is not necessary to make a channel
clock frequency much higher even considering the recording data
rate.
[0180] In this experiment, recording/reproduction was able to be
carried out under the fixed conditions from the radius of 25 mm to
58 mm of the disk 101. Although the object lens 102a may collide
the sheet-like record disk 101 in case it is of a rigid body like a
conventional optical disc due to surface vibration of the disk, and
thereby, error may occur. However, in this experiment according to
the fifth embodiment of the present invention, no such problematic
matters occurred.
[0181] The sheet-like record disk 101 and guide member 104 may
contact for a moment in an vertical vibration state (vibration on
approximately .+-.0.5 mm) before entering in a stable state from
the state in which the sheet-like record disk 101 bends due to
gravity in the free state. However, since the guide member 104 and
the sheet-like record disk 101 approach when the guide member 104
is made to approach, the force of air flow becomes stable, and
thereby, they are then apart accordingly. In order to carry out
recording/reproduction, the distance between the object lens 102a
of the optical pickup 102 and the record film of the disk 101
should approach into approximately 0.1 through 0.2 mm.
[0182] For this reason, control is made such that, when the guide
member 104 projects and thereby the sheet-like record disk 101 is
thus stabilized, the optical pickup 2 projects. The optical pickup
2 should move vertically only at the beginning after that. That is,
the object lens 102a of optical pickup 102 moves greatly, when
searching for the focus state. After that, as the sheet-like record
disk 101 is stable on the guide member 104 as mentioned above, it
is not necessary for the optical pickup 102 to move greatly. As it
is thus possible for the optical pickup 102 not to need to move
greatly during the stable state, the optical pickup 2 can be made
light-weighted.
[0183] Accordingly, in order to achieve the light-weighted optical
pickup 102, the control is made such that the optical pickup 102
projects after the sheet-like record disk 101 is stabilized. The
guide member 104 is moved so that the optical pickup 2 should not
move greatly, and operation of searching for the laser-beam
condensation point is performed not positional control of the
object lens 102a but of the guide member 104 in this embodiment.
Thereby, according to the fifth embodiment of the present
invention, the amount of stroke of the optical pickup 102 can be
reduced remarkably into approximately +50 through 60 micrometers,
with respect to approximately 1 mm of stroke amount on a
conventional optical pickup.
[0184] A sixth embodiment of the present invention will now be
described. The sixth embodiment is same as the above-described
fifth embodiment except that the record film of the sheet-like
record disk 101 is different as follows:
[0185] 150 nm of Ag reflective layer;
[0186] 8 nm of SiC protection layer;
[0187] 10 nm of AgInSbTeGe phase-change record layer; and
[0188] 30 nm of ZnS--SiO protection layer
are formed on the base member 101b by sputtering.
[0189] Then, recording/reproduction of signal was carried out onto
this sheet-like record disk through the recording/reproducing
device (drive device) same as that in the fifth embodiment in an
experiment. The recording/reproduction of random data modulated
could be recorded and reproduced according to 1-7 modulation scheme
by record peak power of 5 mW, erase power of 2.7 mW, reproduction
power of 0.3 mW, channel clock frequency of 66 mHz, 0.13
micrometers/bit on the minimum mark length, and land & groove
recording form of track pitch of 0.32 micrometers. This is
equivalent to the storage capacity of 20 GB.
[0190] Recording/reproduction was able to be carried out on the
fixed conditions over the radius of 25 mm and 58 mm. Since the
phase-change recording medium is used in the sixth embodiment, no
magnetic head is needed. Moreover, direct overwrite is possible in
this embodiment.
[0191] FIG. 26 is a block diagram showing the servo control system
which is a variant form of the same shown in FIG. 25 in the fifth
embodiment. This servo control system shown in FIG. 26 is same as
that shown in FIG. 25, except that a vibration sensor 115 is
attached to the guide member 104. Since abnormal vibration of the
sheet-like record disk 101 occurring if any is transmitted into the
guide member 104, detection of such abnormal vibration can be made
by the vibration sensor 115 thus provide in the guide member
104.
[0192] FIG. 27 is a block diagram showing another variant
embodiment of the servo control system of FIG. 25. The servo
control system shown in FIG. 27 is same as that shown in FIG. 25
except that a vibration sensor 116 is attached to a bearing of the
spindle 107a. Since abnormal vibration of the sheet-like record
disk 101 occurring if any is transmitted into the spindle 107a,
detection thereof may be made by means of the vibration sensor 116
provided in the spindle 107a.
[0193] Thus, according to the fifth embodiment of the present
invention, even on an optical head for high recording density with
a high NA and a narrow tilt margin and/or defocus margin, it became
unnecessary to consider the degree of perpendicularity of the
spindle, surface vibration (or axial runout) of the flexible
disk-like recording medium, etc. For this reason, a low-cost
high-density optical disk system is achieved.
[0194] Moreover, since the guide actuators 105 for fine positional
adjustment of the guide member 104 are provided in the fifth
embodiment, high assembly accuracy is not needed on the guide
member 104.
[0195] Moreover, since the guide actuators 105 control the
projecting amount of the guide member 104 so as to reduce the focus
offset of the object lens 102a, the object lens is thus made
positioned in the central point of the actuator of the object lens,
and, thus, control should be made for the object lens 102a only for
high-frequency surface vibration of the disk 101. Therefore, the
stroke of the actuator of object lens 2a can be designed
smaller.
[0196] Moreover, accuracy is not required in chucking operation of
the sheet-like record disk 101 onto the spindle. This is because,
as long as the positioning on the record disk 101 is made roughly,
the guide member 104 itself can perform operation for searching for
optimum position with respect to the present position of record
disk 101 by means of the function of the guide actuators.
[0197] In case abnormal variation occurs on the sheet-like record
disk 101 due to temperature, humidity, substrate thickness thereof
etc. during rotation thereof, it is detected through the guide
member 104 or spindle 107a. In such a case, there is a possibility
that surface vibration on the disk 101 may not be effectively
reduced, and the sheet-like record disk 101 and object lens 102a
may collide in case the object lens 102a has a small operational
distance range. However, according to the fifth embodiment, the
optical pickup 102 and sheet-like record disk 101 can be protected
from breakage because there is a provision which detects an extreme
abnormal vibration and thereby the appropriate measures are taken
for avoiding actual collision as mentioned above (for example, the
optical pickup 102 itself is made retreat immediately as mentioned
above).
[0198] In addition, it is possible to consider various variant
embodiment of the fifth embodiment of the present invention. For
example, although in the fifth embodiment the sheet-like record
disk is of writable, the concept o the fifth embodiment is also
applicable to a disk-like recording medium of ROM type.
[0199] Thus, according to the fifth embodiment of the present
invention, high-density record can be enabled by finely adjusting
distance between the disk type recording medium and object lens by
means of the guide member, by effectively making the movable range
of the object lens smaller and reducing the weight of the optical
head mechanism, and also, by improving high-frequency response
thereof, etc.
[0200] Moreover, since abnormal vibration is detectable by the
vibration sensor, breakage of optical head and breakage of medium
are effectively avoidable.
[0201] A seventh embodiment of the present invention will now be
described.
[0202] In the first embodiment described above with reference to
FIG. 1, the stabilization guide member 8 for generating the
Bernoulli's effect by the convex-like curved surface of arbitrary
curvature in the surface on the projecting end thereof. The
inventors further studied in order to attain further stabilization
and simplification of recording/reproduction operation in the
optical recording/reproducing device having such a stabilization
guide member. As a result, they devised to adjust the tilt angles
along the radius direction and along rotation tangent direction of
the optical disc of the stabilization guide member. The seventh
embodiment of the present invention has been devised based on this
concept, and details thereof will now be described.
[0203] In the basic configuration of generating the Bernoulli's
effect between the optical disk and stabilization guide member, the
position of the surface vibration stabilization area on the optical
disk with regard to the stabilization guide member created in case
this guide member is made approach the optical disk in the
direction along the rotational axis of the optical disk depends on
the specification of the optical disk, the projection amount of the
guide member (approaching distance), rotation speed of the disk,
and so forth.
[0204] Further, this stabilization area moves along the surface of
the optical disk. It became possible to set up correctly this
stabilization area on the optical disk by appropriately controlling
the tilt angles of the stabilization guide member along the disk
radius direction and disk rotational tangential direction. In fact,
by this control operation, it is possible to set up this
stabilization area into an arbitrary position on the disk surface
with respect to the position of the guide member. Thereby, it
becomes possible to control the stabilization area on the optical
disk obtained thanks to the Bernoulli's effect, and to
eliminate/stabilize the surface vibration in recording/reproducing
onto the optical disc.
[0205] In addition, the directions along which the tilt angle of
the stabilization guide member is controlled are not limited to the
optical disk radius direction and optical disk rotational
tangential direction as mentioned above. It is also possible to
rotate these directions along which the tilt angle of the guide
member is controlled by 45.degree., for example. Also in such a
case, the substantially the same effect can be obtained.
[0206] Further, the shape of the surface at the projection end of
the stabilization guide member may also be changed from a spherical
shape. Foe example, any special shape such as an aspherical shape
may be applied as long as the Bernoulli's effect can be obtained
between the stabilization guide member having such a shape of
projection end and an optical disk such as to eliminate/stabilize
surface vibration on the optical disk.
[0207] Further, according to the seventh embodiment of the present
invention, the rotational center or tilt center of the
stabilization guide member on the above-mentioned tilt angle
control is set up at a position on a curved surface at a projection
end of the stabilization guide member, and, this position is
regarded as an operation reference position of the stabilization
guide member. Thereby, it is possible to determine a spatially
fixed point as the operation reference position of the
stabilization guide member regardless of the above-mentioned tilt
control operation of the stabilization guide member. Accordingly,
even when the tilt angle of the stabilization guide member is
controlled so as to control the surface vibration on the optical
disk, it is possible to fix the surface vibration stabilization
area on the optical disk at or around a predetermined spatial
position on the optical disk. Thereby, it is possible to easily
achieve stable and positive operation of the optical pickup on this
position.
[0208] As to operation of: the optical pickup, the laser beam
emitted thereby should be incident on the above-mentioned operation
reference position of the stabilization guide member
vertically/perpendicularly. Also, a temporary focus position of the
optical pickup before performing focus servo control should be
positioned at the above-mentioned operation reference position of
the stabilization guide member. For this purpose, the position of
the optical pickup is controlled according to the position of the
stabilization guide member. Thereby, it is possible to accurately
control the focus position and tilt angle of the optical pickup
with respect to an arbitrary position on the optical pickup at
which surface vibration is eliminated/stabilized thanks to the
Bernoulli's effect Thereby, it is possible to perform stable
recording/reproducing onto the optical disk.
[0209] Further, according to an eighth embodiment, which is a
variant embodiment of the above-mentioned seventh embodiment (see
FIG. 32) of the present invention, the stabilization guide member
and optical pickup are previously fixed onto a common supporting
member (249) in a state in which the temporary focus position of
the optical pickup before performing focus servo control is
positioned at the above-mentioned operation reference position of
the stabilization guide member, and also, the laser beam emitted
from the optical pickup is incident on the above-mentioned
operation reference position of the stabilization guide member
vertically. That is, a tilt angle control mechanism on the
stabilization guide member is mounted on the above-mentioned common
supporting member.
[0210] Thereby, it is possible to omit rough movement control on
the focus position and tilt angle for the optical pickup. Such a
configuration is effective for a disk drive device which does not
need very fine accuracy. This is because, in this configuration,
all the configuration needed for the above-mentioned rough movement
control on the optical pickup can be omitted, and, thus, device
cost can be effectively lowered. Further, in this configuration, it
is possible to perform fine movement control on focus position and
tilt angle of the optical pickup at high accuracy by providing
control mechanism designed for only the fine movement control.
[0211] Moreover, by sifting the above-mentioned temporary focus
position of the optical pickup from the operation reference
position of the stabilization guide member along minus direction by
the substrate thickness of the optical disk, in each of the
above-mentioned seventh and eighth embodiments, the control
accuracy of the temporary focus position of the optical pickup with
respect to the optical disk can be improved, and the withdrawing
action in the focus servo control can be carried out more
efficiently.
[0212] Moreover, the above-mentioned operation reference position
of the stabilization guide member is set at an arbitrary radius
position at which recording/reproduction is performed on the
optical disk, and, there, the position control and tilt angle
control of the stabilization guide member is then performed so as
to control the surface vibration on the optical disk at the
above-mentioned operation reference position. Thereby, it is
possible to achieve surface vibration elimination/stabilization
thanks to Bernoulli's effect at an arbitrary radius position on the
optical disk. Thereby, it is possible to perform stable
recording/reproducing onto the optical disk.
[0213] Furthermore, previously, according to a test/experiment,
appropriate values of control amount on position of the
stabilization guide member with respect to the optical disk
surface, and also, control amount on tilt angle of the
stabilization guide member are obtained as setting values for each
radius position on the optical disk used for recording/reproducing.
Then, at an actual occasion of recording/reproducing, the position
and tilt angle of the stabilization guide member are controlled
according to these setting values of control amounts with respect
to the relevant radius position. Thereby, it is possible to move
the stabilization guide member into the appropriate position and
title angle at high speed at which the surface vibration of the
optical disk can be eliminated/stabilized properly.
[0214] Further, by providing a sensor (referred to as a gap sensor,
hereinafter) for measuring a gap between the stabilization guide
member and optical disk at the above-mentioned operation reference
position on the stabilization guide member, feedback control on a
control driving system for the stabilization guide member may be
applied based on the thus-measured gap. For example, by controlling
the tilt angle of the stabilization guide member so as to make the
measured gap minimum, it is possible to easily achieve the surface
vibration stabilization effect thanks to Bernoulli's effect at the
optimum conditions. Thereby, it is possible to perform
recording/reproducing at the best point on the optical disk at high
quality. Alternatively, also by controlling the tilt angle of the
stabilization guide member in a real-time manner so as to cause the
measured gap minimum, the same effect can be obtained.
[0215] As the gap sensor for measuring the above-mentioned gap, a
photonics sensor, an electrostatic capacity type displacement
sensor or the like can be used. Other than them, any device which
can measure the gap between an arbitrary position on the
stabilization guide member and optical disk can be used.
[0216] The above-mentioned measured gap may be used as a minus
correction value in determining the above-mentioned temporary focus
position of the optical pickup before performing the focus servo
control. Thereby, even when the floating amount of the optical disk
with respect to the stabilization guide member thanks to the
Bernoulli's effect is large, setting of the temporary focus
position of the optical pickup can be made accurately.
[0217] Furthermore, as mentioned above, previously, according to a
test/experiment, appropriate values of control amount on position
of the stabilization guide member with respect to the optical disk
surface, and also, control amount on tilt angle of the
stabilization guide member are obtained as setting values for each
radius position on the optical disk used for recording/reproducing.
Then, at an actual occasion of recording/reproducing, the position
and tilt angle of the stabilization guide member are controlled
according to these setting values of control amounts with respect
to the relevant radius position. Furthermore, according to the
above-mentioned gap amount measured by means of the above-mentioned
gap sensor at the time, the thus obtained position and tilt angle
are further finely adjusted. Thereby, it is possible to move the
stabilization guide member into further appropriate position and
tilt angle at high speed at which the surface vibration of the
optical disk can be eliminated/stabilized properly.
[0218] The optical information recording/reproducing device in the
above-mentioned seventh embodiment of the present invention will
now be described specifically with reference to FIG. 28. The
configuration of this recording/reproducing device is almost same
as that in the first embodiment described with reference to FIG. 1.
Specifically, the optical disk 201 is generally the same as the
optical disk 1 described with reference to FIG. 3.
Recording/reproduction by the optical pickup 206 onto this optical
disc 201 being performed from the side of the record layer 20 made
of a material such as AgInSbTeGe, while the stabilization guide
member 208 for controlling the surface vibration of the optical
disk 201 is disposed on the side of the substrate 21 opposite to
the side of the record layer 20 (see FIG. 3). The stabilization
guide member 208 is formed into a shape of a pillar, and is formed
into a convex with a curvature radius of 50 mm at the projection
end thereof facing the optical disk 201.
[0219] Furthermore, for example, the optical disk 201 is made from
a polycarbonate sheet which has a diameter of 120 mm, and a
thickness of 75 micrometers is used as the base member. First, a
groove of pitch 0 6 micrometers and a width 0.3 micrometers of a
stamper is transferred by heat transfer on the sheet made from
polycarbonate, and the following films are formed by sputtering in
the stated order: sheet/Ag reflective layer of 120
nm/(ZrO.sub.2--Y.sub.2O.sub.3)--SiO.sub.2 7 nm/AgInSbTeGe 10
nm/ZnS--SiO.sub.2 25 nm/Si.sub.3N.sub.4 10 nm.
[0220] The information recording area on this optical disk 201 is
set as a range of (20 mm-55 mm radius) from the inner circumference
diameter of 40 mm to the perimeter diameter of 110 mm. Then,
through spin coat, UV resin is coated, it is made to set by
ultraviolet ray irradiation, and a transparent protection film with
a thickness of 5 micrometers is formed. Moreover, a hard coating
with a thickness of 10 micrometers is provided on the side opposite
to the side of the above-mentioned transparent protection film. In
addition, the hub 203 of the outer diameter of 30 mm and inner
diameter of 15 mm, and the thickness of 1.1 mm is attached in the
central part of this optical disc 201.
[0221] In FIG. 28, a stabilization guide tilt/position adjustment
control part 209 includes a disk rotation axis directional guide
position adjustment control part 221; a disk radius directional
guide position adjustment control part 222, a disk radius
directional guide tilt angle adjustment control part 223, and a
disk rotational tangent directional guide tilt angle adjustment
control part 224. A pickup tilt/position adjustment control part
207 includes a disk rotational axis directional pickup position
adjustment control part 225, a disk radius directional pickup
position adjustment control part 226, a disk radius directional
pickup tilt angle adjustment control part 227 and a disk rotational
tangent directional pickup tilt angle adjustment control part 228,
and movement and rotation are attained according to arrows shown in
the figure, respectively.
[0222] The disk radius directional guide tilt angle adjustment
control part 223 and the disk rotational tangent directional guide
tilt angle adjustment control part 224 control the tilt angles of
the stabilization guide member 208 with respect a surface central
position thereof as the rotational center along the disk (201)
radius direction and disk (201) rotational tangent direction,
respectively.
[0223] The disk rotation directional pickup tilt angle adjustment
control part 227 and the disk rotation tangent directional pickup
tilt angle adjustment control part 228 control the tilt angles with
respect to the focus position of the optical pickup 206 as the
rotational center along the disk (201) radius direction and disk
(201) rotational tangent direction, respectively. Further, a
setting is made such that the laser beam La from the laser light
source 214 in the optical pickup 206 descried with reference FIG. 4
is always incident on the stabilization guide member 208 at the
above-mentioned surface central position perpendicularly, and,
also, the temporary focus position of the optical pickup 206 before
focus servo control is performed is positioned at the
above-mentioned surface central position of the stabilization guide
member 208.
[0224] The optical disk 201 is set onto the spindle shaft 202, and,
then the stabilization guide member 208 is pressed onto the optical
disk 201. In this state, the tilt angles of the stabilization guide
member 208 along the disk radius direction and disk tangential
direction are adjusted through the disk radius direction guide tilt
angle adjustment control part 223 and the disk rotational tangent
direction guide tilt angle adjustment control part 224. The
above-mentioned adjustment is made such that the surface vibration
at the surface center of the stabilization guide member 208 becomes
minimum. According to the seventh embodiment of the present
invention, the adjustment control amount on the displacement of the
stabilization guide member 208 with respect to the optical disk 201
and the adjustment control amount on the tilt angle of the same are
determined by using values previously estimated by performing trial
operation according to the specification of the optical disk 201
and rotation speed of the optical disk 201.
[0225] As a result of performing the operation control on the
stabilization guide member 208 and optical pickup 206 as described
above, it is possible to set the surface vibration stabilization
area created by the stabilization guide member 208 easily and
appropriately, and, to perform recording/reproducing onto the
optical disk at this area stably.
[0226] As a result of an experiment performed according to the
above-described conditions, the surface vibration on the point at
which recording/reproducing is performed by the optical pickup 206
was shown in FIG. 29. As can be seen therefrom, the surface
vibration could be controlled well within 3 micrometers. In FIG.
29, the solid line denotes the surface vibration waveform at a time
optimum setting was made on the tilt angle of the stabilization
guide member 208 in the seventh embodiment of the present invention
while the broken line denotes the same at a time the tilt angle is
deviated from the optimum value.
[0227] Furthermore, as described above, the gap sensor is provided
at the surface center of the stabilization guide member 208 for
measuring the gap between the stabilization guide member 208 and
optical disk 201, and then, the tilt angles of the stabilization
guide member 208 are adjusted so as to minimize the gap, or so as
to minimize the change in (or fluctuation of) the gap. Thereby,
according to the experiment, it is possible to perform
recording/reproducing operation at the effective surface vibration
stabilization area more appropriately and at high accuracy.
[0228] According to the seventh embodiment, an electrostatic
displacement sensor is used as the gap sensor. Further, according
to the experiment, it could be confirmed that same effect can be
obtained from both of the above-mentioned adjustment methods
directed to minimization of the gap and directed to minimization of
the change in (or fluctuation of) the gap.
[0229] FIG. 30 illustrates a configuration of a comparison example
of optical recording/reproducing device with respect to the seventh
embodiment. In this configuration, the same reference numerals are
given to components same as those shown in FIG. 28, and description
thereof is omitted. In this configuration, a disk surface direction
guide positional control part 230, a disk-surface guide-moving-path
inclination control part 231, a disk rotational axis directional
guide position control part 232, a disk radius directional guide
position control part 233, a disk-surface directional pickup
position control part 234, a disk-surface pickup-moving-path
inclination control part 235, a disk rotational axis directional
pickup position control part 236 and a disk radius direction pickup
position control part 237 are provided. These parts can move/rotate
according to arrows shown in the figure, respectively. According to
this comparison example, no tilt adjustment/control parts as in the
seventh embodiment are provided.
[0230] Similar to the case of the seventh embodiment, surface
vibration stabilization operation on the optical disk by means of
the stabilization guide member 208 was performed on the
above-mentioned comparison example in experimental. As a result, as
shown in FIG. 31, the central position of the stabilization guide
member 208 and the surface vibration stabilization area were
positioned at a different position, where, in FIG. 31, 240 denotes
a position of the stabilization guide member 208 projected on the
optical disk 201, while 241 denotes the surface vibration
stabilization area on the optical disk 201, and 242 denotes the
rotation direction of the optical disk 201.
[0231] Furthermore, in the experiment performed on the comparison
example shown in FIG. 30, the surface vibration stabilization area
with respect to the surface of the stabilization guide member 208
varied according to the position on the optical disk along the
radius direction thereof, disk rotational speed, specification of
the optical disk and so forth. And thereby, it was very difficult
to cause the optical pickup 206 to properly follow the surface
vibration stabilization area 241, and, for this purpose, it was
necessary to provide a special operation mechanism and also, to
provide a complex control algorithm therefor.
[0232] FIG. 32 shows a general configuration of the information
recording/reproducing device in the above-mentioned eighth
embodiment of the present invention. In the configuration, the same
reference numerals are given to components same as those shown in
FIG. 28, and description thereof is omitted.
[0233] This eighth embodiment includes a guide pickup unit common
housing 249 having a C-shape and holding the optical pickup 206 and
stabilization guide member 208 in a manner such that they face one
another, a disk rotational axis direction unit position adjustment
control part 250, a disk radius direction unit position adjustment
control part 251, a disk radius direction unit tilt angle control
part 252, and a disk rotational tangential direction unit tilt
angle control part 253.
[0234] The disk radius direction unit tilt angle adjustment control
part 252 and the disk rotation tangent direction unit tilt angle
adjustment control part 253 have mechanisms such as to control the
tilt angles of the stabilization guide member 208 along the disk
radius direction and disk tangential direction with respect to the
surface center of the stabilization guide member 208 as the
rotational center. Further, the optical pickup 206 is fixed to the
common housing 249 in a state such that the laser beam emitted from
the optical pickup 206 is always incident on the stabilization
guide member at the surface center perpendicularly, and, also, the
temporary focus position of the optical pickup 206 before
performance of the focus servo control operation is located at the
surface center of the stabilization guide member 208.
[0235] Also in this eighth embodiment, the optical disk 201 is set
onto the spindle shaft 202, and, then the stabilization guide
member 208 is pressed onto the optical disk 201. In this state, the
tilt angles of the stabilization guide member 208 along the disk
radius direction and disk tangential direction are adjusted through
the disk radius direction unit tilt angle adjustment control part
252 and the disk rotational tangent direction unit tilt angle
adjustment control part 253. The above-mentioned adjustment is made
such that the surface vibration at the surface center of the
stabilization guide member 208 becomes minimum.
[0236] Also according to the eighth embodiment of the present
invention, the adjustment control amount on the displacement of the
stabilization guide member 208 with respect to the optical disk 201
and the adjustment control amount on the tilt angle of the same are
determined by using values previously estimated by performing trial
operation according to the specification of the optical disk 201
and rotation speed of the optical disk 201.
[0237] As a result of performing the operation control on the
stabilization guide member 208 and optical pickup 206 as described
above, it is possible to set the surface vibration stabilization
area created by the stabilization guide member 208 easily and
appropriately, and, to perform recording/reproducing onto the
optical disk at this area stably. As a result of an experiment
performed according to the above-described conditions, the surface
vibration on the point at which recording/reproducing is performed
by the optical pickup 206 could be controlled well as in the case
of the seventh embodiment. Further, as to the effect of the gap
sensor and so forth, the same results were obtained as those in the
case of the seventh embodiment.
[0238] According to the eighth embodiment, as the stabilization
guide member 208 and optical pickup 206 are integrated into a unit
as mentioned above, it is possible to simplify the operation
mechanism therefor, while the same advantages can be obtained as
those in case of the seventh embodiment can be obtained.
Accordingly, it is possible effectively reduce the device
costs.
[0239] As described above, in the seventh and eighth embodiments of
the present invention, it is possible to easily adjust an area at
which the surface vibration is eliminated/stabilized thanks to the
stabilization guide member on the optical disk by controlling the
tilt angles of the stabilization guide member along the radius
direction of the optical disk and tangential direction of the
optical disk. Thereby, it is possible to appropriately set a
desired area on the optical disk which should be stabilized in
surface vibration, to simplify and improve accuracy on the control
of position and tilt angle of the optical pickup which performs
recording/reproducing operation on this stabilization area.
Accordingly, it is possible to stabilize and simplify
recording/reproducing operation.
[0240] A ninth embodiment of the present invention will now be
described.
[0241] When rotating the sheet-like optical disk at an arbitrary
rotation speed, in order to stabilize/eliminate surface vibration
at an arbitrary position along the disk radius direction in an
information recording/reproducing device by means of the
stabilization guide member in any of those described above, it is
important to determine the position of the stabilization guide
member along the direction of the rotational axis of the optical
disk according to an experiment. Accordingly, even when the
position along the disk radius direction and/or disk rotation speed
is changed, it is possible to effectively control the surface
vibration (or axial runout) on the disk by the stabilization guide
member by appropriately controlling the position of the
stabilization guide member along the disk rotational axis
direction, as will be described now.
[0242] Requirements for controlling the surface vibration depend on
the specification of the optical disk will now be described. For
example, estimation is previously made by actual measurement of the
position of the stabilization guide member along the disk
rotational axis direction enabling well control of the surface
vibration of the optical disk at any position on the optical disk
along the radial direction and any disk rotation speed for every
specification of the disk such as the sheet material, respective
composition layers such as the substrate, record layer and so
forth, mechanical property, and process conditions of the optical
disk.
[0243] Then, therefrom, an adjustment pattern concerning the
position of the stabilization guide member along the disk
rotational axis direction is set for every specification of
respective optical disks. Then, the adjustment pattern applied is
appropriately selected according to the optical disk applied.
Thereby, it is possible to cope with alternation of the
specification of optical disk applied, sufficiently. In addition,
the specification of optical disks are intricately related to many
factors, and thus, it can be said that it is impossible to find out
a law concerning these factors. Thus, in terms of effectiveness and
practical usage, it is necessary that the most effective adjustment
pattern is selected according to each particular type of the
optical disk applied as mentioned above.
[0244] Furthermore, according to an experiment, it is found that,
as shown in FIG. 34, a movement path 325 of the stabilization guide
member 308 along a disk radius direction along which the effect of
stabilization/elimination of surface vibration by means of the
stabilization guide member 308 lies along approximately a straight
line for a particular disk rotation speed, and, also, is inclined
from a plane perpendicular to the disk rotational axis.
[0245] In FIG. 34, 306a denotes a reference position of the optical
pickup 306; 308a denotes a reference position of the stabilization
guide member 308; 327 denotes a moving path of vibration
stabilization point on the disk surface; 328 denotes a movement
path of the optical pickup 306; .alpha.1 denotes an inclination
angle of the movement path 327 (referred to as a disk vibration
stabilization point movement path 327, hereinafter) of vibration
stabilization point on disk surface with respect to the plane
perpendicular to the disk rotational axis; .alpha.2 denotes an
inclination angle of the movement path 328 (referred to as a pickup
movement path 328, hereinafter) of the optical pickup 306 with
respect to the plane perpendicular to the disk rotational axis;
.alpha.3 denotes an inclination angle of the movement path 325
(referred to as a guide movement path 325, hereinafter) of the
stabilization guide member 308 providing most effective surface
vibration stabilization effect with respect to the plane
perpendicular to the disk rotational axis.
[0246] Further, it is also found that the position of the guide
movement path 325 along the disk rotation axis shifts while the
inclination angle .alpha.3 thereof is maintained according to
change in the rotational speed of the optical disk. Further, the
inclination angle .alpha.3 of the guide movement path 325, the
position of the guide movement path 325 and the change rate of this
position with respect to the disk rotational speed defer according
to every particular specification of the optical disk.
[0247] Thus, by appropriately changing the inclination angle
.alpha.3 of the guide movement path 325 with respect to the plane
326 perpendicular to the disk rotation axis, and changing the
position of the guide movement path 325 along the disk rotation
axis, it is possible to obtain the effect of surface vibration
stabilization by means of the stabilization guide member 308
regardless of the particular specification of the optical disk,
and, thus, to cope with alteration of the specification of the
optical disk, sufficiently.
[0248] Moreover, by adjusting the position along disk rotation axis
direction of the guide movement path 325 according to the
specification of the optical disk 302 applied and also disk
rotation speed, it is possible to obtain the effect of surface
vibration stabilization by means of the stabilization guide member
308 regardless of the disk rotation speed on the same optical disk
308. Accordingly, recording/reproduction onto the optical disk can
be performed without being defined by the restriction on the
recording line speed. Moreover, according to the above-described
scheme, disk surface vibration stabilization is able to be achieved
simply without using complicated control algorithm.
[0249] Together with the positional control of the guide movement
path 325 along the disk rotation axis, positional control of the
optical pickup 306 is needed corresponding to the movement of the
stabilization guide member 308. In this control, it is effective,
according to an experiment, to fix the positional relationship
between the stabilization guide member 308 and optical pickup 306
along the disk rotation axis direction. Thereby, it becomes
possible to appropriately set the position on the optical disk 301
which is stabilized in surface vibration by means of the
stabilization guide member and the pre-focus distance on the
optical pickup 306 at this position.
[0250] The pre-focus distance means a distance between a reference
position on focus servo control with respect to the optical disk
301 in information recording/reproduction onto the optical disk
301, and it is different from a focus distance in focus servo
control in response to slight surface vibration, or so.
[0251] Further, according to the experiment, it is found that the
disk surface vibration stabilization area on the disk surface
obtained by means of the stabilization guide member and the
position of this stabilization guide member are different, and, in
case where the position of the stabilization guide member along the
disk radius direction and along the disk rotation axis direction
are fixed, this mutual positional relationship depends on the disk
rotation speed.
[0252] Further, in case the disk rotation speed is fixed, as shown
in FIG. 35, both the guide movement path 325 and disk vibration
stabilization point movement path 327 lie along approximately
straight lines, respectively, and, also, have an angle .theta.
therebetween. This mutual position relationship between the guide
movement path 325 and disk vibration stabilization point movement
path 337 depends on the disk rotation speed, and, the
above-mentioned mutual positional relationship changes according to
the change in disk rotation speed while above-mentioned angle
.theta. is maintained. The manner of this phenomenon also depends
on the particular specification of the optical disk 301, and, the
shift angle .theta. between the guide movement path 325 and disk
vibration stabilization point movement path 327, the mutual
positional relationship therebetween and also, the change rate of
the mutual relationship with respect to the disk rotation speed are
different according to every particular specification of the
optical disk.
[0253] Accordingly, in order to achieve information
recording/reproducing in a state in which surface vibration of the
optical disk is stabilized, it is effective to control/adjust the
mutual positional relationship between the stabilization guide
member 308 and optical pickup 306 on the disk surface at the
optical disk recording/reproducing position, with respect to the
disk rotation speed as a control/adjustment parameter.
[0254] For this purpose, for every particular optical disk
specification, positional relationship on the disk surface between
the position of the stabilization guide member 308 and the position
at which the disk surface vibration is stabilized by means of the
stabilization guide member 308 on the disk surface is estimated
previously. Then, a stabilization guide member positional control
mechanism 309 (see FIG. 33) is provided to control and move the
point at which the disk surface vibration is stabilized along an
arbitrary straight line along disk radius direction on the disk
surface. By applying this stabilization guide member position
control mechanism 309, it is possible to achieve stable information
recording/reproducing at a point at which surface vibration is
stabilized throughout the recording area of the optical disk 301,
and, also, as it is possible to employ a straight line of the
pickup movement path 328, it is possible to simplify the system
configuration of the recording/reproducing device.
[0255] For this control mechanism, any one or both in combination
of a control device of controlling the angle of the guide movement
path 325 along the disk recording surface independently by rotating
the guide movement path 325, and a control device of controlling
the angle of the pickup movement path 328 along the disk recording
surface independently by rotating the pickup movement path 328
is/are employed. Thereby, it is possible to control the mutual
angular position between the guide movement path 325 and pickup
movement path 328 arbitrarily.
[0256] Further, any one or both in combination of an adjustment
method of adjusting the inclination angle of the guide movement
path 325 along the disk recording surface according to the
specification of the optical disk 301 and an adjustment method of
adjusting the inclination angle of the pickup movement path 328
along the disk recording surface according to the specification of
the optical disk 301 is/are applied. Thereby, it is possible to set
the pickup movement path 328 in parallel to the disk surface
vibration stabilization point movement path 327 which is determined
relatively from the position of the guide movement path 325.
[0257] Furthermore, any one or both in combination of a control
device of controlling the position of the guide movement path 325
along the disk recording surface independently, and a control
device of controlling the position of the pickup movement path 328
along the disk recording surface independently is/are employed.
Thereby, it is possible to control the mutual position relationship
between the guide movement path 325 and pickup movement path 328
arbitrarily. Further, any one or both in combination of an
adjustment method of adjusting the position of the guide movement
path 325 along the disk recording surface according to the
specification of the optical disk 301 and disk rotation speed and
an adjustment method of adjusting the position of the pickup
movement path 328 along the disk recording surface according to the
specification of the optical disk 301 and disk rotation speed
is/are applied. Thereby, it is possible to make the pickup movement
path 328 to coincide with the disk surface vibration stabilization
point movement path 327 which is determined relatively from the
position of the guide movement path 325.
[0258] Furtherer, by appropriately combining the above-described
control devices and methods, it is possible to set the pickup
movement path 328 along the disk surface vibration stabilization
point movement path 327, and, thus, to achieve stable information
recording/reproducing at a disk surface vibration stabilization
point regardless of disk rotation speed, position of information
recording/reproducing on the disk surface along disk radius
direction, and the specification of the optical disk.
[0259] The optical information recording/reproducing device
carrying the optical disk drive in the above-described ninth
embodiment of the present invention will now be described with
reference to FIG. 33. Basically, the configuration of this
recording/reproducing device is same as the recording/reproducing
device in the seventh embodiment shown in FIG. 28 except the
configuration relating to a mechanism of controlling the
stabilization guide member 308 (208) and optical pickup 306 (206).
In fact, the components 301, 302, 303, 304, 305, 306, and 308 are
the same as those 201, 202, 203, 204, 205, 206, and 208 shown in
FIG. 28, respectively, and description thereof is omitted.
[0260] The specification of the optical disk 301 applied is the
same as the specification of the optical disk 201 according to
seventh embodiment described above with reference to FIG. 3, and is
referred to as a sheet specification A.
[0261] The above-mentioned stabilization guide position setting
mechanism 309 in this configuration includes a disk-surface
directional guide position control part 333, a disk-surface guide
movement path inclination control part 334, a disk-rotation-axis
directional guide position control part 335, a guide movement path
inclination angle control part 336 and a disk-radius directional
guide position control part 337. Further, a pickup position setting
mechanism 307 includes a disk-surface directional pickup position
control part 338, a disk-surface directional pickup movement path
inclination control part 339, a disk rotational-axis directional
pickup position control part 340, a pickup movement path
inclination angle control part 341, and a disk-radius directional
pickup position control part 342. They move/rotate according to
arrows shown in the figure, respectively.
[0262] A pattern of movement operation of the stabilization guide
member 308 and optical pickup 306 at a time of performance of
information recording/reproducing onto the optical disk 301 having
the above-mentioned sheet specification A is referred to as a guide
pickup operation pattern A. This operation pattern A is previously
prepared based on actually measured values, or the like, for
particular optical disk to be applied, and, the positions of
stabilization guide member 308 and optical pickup 306 are
controlled according to this operation pattern A in response to the
disk rotation speed and position of recording/reproducing along the
disk radius direction.
[0263] The outline of the guide pickup operation pattern A will now
be described with reference to FIGS. 36 and 37.
[0264] As shown in FIG. 36, the guide movement path 325-1, 325-2 or
325-3 is inclined with respect to the plane 326 perpendicular to
the disk rotation axis by the angle .alpha.3 by means of the guide
movement path inclination angle control part 336. For example, this
angle .alpha.3=3 (degrees). Further, the pickup movement path
328-1, 328-2 or 328-3 is inclined with respect to the plane 326
perpendicular to the disk rotation axis by the angle .alpha.2 by
means of the pickup movement path inclination angle control part
341. For example, this angle .alpha.2=3 (degrees).
[0265] Further, as shown in FIG. 37, the mutual angle .theta.
between the guide movement path 325 and pickup movement path 328 on
the disk surface is set as 3 (degrees) by means of the disk-surface
guide movement path inclination control part 334.
[0266] The guide movement path 325 is shifted along the disk
rotation axis direction by means of the disk-rotation-axis
directional guide position control part 335 (see FIG. 36), and/or
is shifted along the disk surface direction by means of the
disk-surface directional guide position control part 333 (see FIG.
37), according to the disk rotation speed, while the
above-mentioned guide movement path inclination angle .alpha.3 is
maintained. The direction to be thus shifted is such as from the
above-mentioned 325-3 to 325-1 as the disk rotation speed
increases, i.e., the direction to cause the stabilization guide
member to project toward the optical disk 301, or the direction to
cause the stabilization guide member 308 to be apart from the
pickup movement path 328 on the disk surface (or along the
recording surface)
[0267] The direction of the pickup movement path 328 on the disk
surface is fixed along a disk radius direction, and, thus, the
disk-surface directional pickup position control part 338 and the
disk-surface directional pickup movement path inclination control
part 339 are not used, in this example.
[0268] The pickup movement path 328 is controlled by the
disk-rotational-axis directional pickup position control part 340
in a manner such as to follow the guide movement path transition
according to the disk rotation speed (325-1 through 325-3 shown in
FIG. 36) while the distance between the stabilization guide member
308 and optical pickup 306 along the disk rotational axis direction
is fixed.
[0269] The mutual relationship between the position of the
stabilization guide member 308 along the guide movement path 325
and the position of the optical pickup 306 along the pickup
movement path 328 are adjusted/controlled according to a previously
estimated pattern as shown in FIG. 38 on the optical disk having
the sheet specification A. FIG. 38 shows a position at which
surface vibration is stabilized on the optical disk along the
pickup movement path 238 created when the stabilization guide
member 308 is positioned at an arbitrary position along the guide
movement path 325, and, a curve is obtained according to a
particular disk rotation speed. As for any disk rotation speed
other than those previously measured particularly, setting is made
by extrapolation manner from given ones.
[0270] Thus, in an experiment on the optical disk 301 having the
sheet specification A, according to the above-mentioned guide
pickup operation pattern A, the positions of the stabilization
guide member 308 and optical pickup 306 were controlled.
Accordingly, over the information recording area in a range between
20 mm and 50 mm radius on the disk surface, the Bernoulli's effect
could be obtained by means of the stabilization guide member 308
stably. Then, as shown in FIG. 39, the disk surface vibration could
be controlled well within 3 micrometers at a position at which
recording/reproducing is performed by the optical pickup 306. Thus,
stable information recording/reproducing could be achieved.
[0271] Further, the control mechanisms for performing positional
control/adjustment of the stabilization guide member 308 and
optical pickup 306 have a very simple configuration. For example,
in case the optical disk 301 applied is fixed to of a specific
specification, the disk-surface directional guide movement path
inclination control part 334, disk-rotational-axis directional
guide position control part 336, disk-surface directional pickup
movement path inclination control part 339 and pickup movement path
inclination angle control part 341 become unnecessary, and can be
configured as a simpler configuration.
[0272] Moreover, in the description of the ninth embodiment, the
position of the pickup movement path 328 is fixed on the disk
surface while the guide movement path 325 is controlled. However,
instead, it is also possible that, as a contrary, the position of
the guide movement path 325 is fixed on the disk surface while the
pickup movement path 328 is controlled.
[0273] As variant embodiments of the ninth embodiment, embodiments
employing the optical disk 301 having different sheet
specifications B and C will now be described.
[0274] The sheet specification B is such that: the sheet member in
the above-mentioned specification A is replaced by a sheet made by
polyethylene telefthalate having a diameter of 120 mm, and a
thickness of 100 micrometers. The sheet specification C is such
that each of all the respective sputter layers of the sheet
specification A is halved in thickness.
[0275] First, for each of the optical disks of the sheet
specifications B and C, similarly, the guide pickup operation
pattern mentioned above was previously estimated. Thus, the guide
pickup operation pattern B and the guide pickup operation pattern C
were determined. In addition, on each of the guide pickup operation
patterns B and C, the pickup movement path 328 was fixed while the
guide movement path 325 was controlled on the disk surface as in
the case of the guide pickup operation pattern A.
[0276] The guide pickup operation pattern B is different from the
guide pickup operation pattern A only in the mutual relationship
between the position of stabilization guide member 308 along the
guide movement path 325 and the position of the optical pickup 306
along the pickup movement path 328 shown in FIG. 38. Accordingly,
based on the pickup operation pattern A, only this different point
was changed and thus, setting was made accordingly.
[0277] The guide pickup operation pattern C is different from the
guide pickup operation pattern A in the inclination angle .alpha.3
of guide movement path 325 with respect to the plane 326
perpendicular to the disk rotation axis to be adjusted by the guide
movement path inclination angle control part 336. This angle is 4
degrees, and setting change was made accordingly. According to this
change, the inclination angle .alpha.2 of pickup movement path 328
with respect to the plane 326 perpendicular to the disk rotation
axis to be adjusted by the pickup movement path inclination angle
control part 341 was also changed into the same angle.
[0278] Thus, by estimating the guide pickup operation pattern for
each specification of optical disk, and then performing control of
the positions of the stabilization guide member 308 and optical
pickup 306 according to the thus-estimate requirements, it was
possible to create the Bernoulli's effect by means of the
stabilization guide member 308 regardless of the particular
specification of the optical disk. Also, thereby, it was possible
to well control surface vibration at a position of
recording/reproducing performed by the optical pickup 306.
According to the experiment, the surface vibration was controlled
well within 3 micrometers in any case.
[0279] Thus, according to the ninth embodiment of the present
invention, as the inclination of the guide movement path 325 with
respect to the plane 326 perpendicular to the disk rotation axis
direction is appropriately set, is appropriately changed according
to particular specification of the optical disk 301, and, also, is
appropriately shifted while the above-mentioned inclination angle
is fixed, it is possible that the stabilization guide member 308
performs the surface vibration stabilization effect in the optimum
conditions corresponding to the various states in bending,
displacement and so forth on the optical disk. Further, as the
positional relationship between the stabilization guide member 308
and optical pickup 306 along the disk rotation axis direction is
fixed, it is possible that the surface vibration stabilization
position on the optical disk 301 and the separating reference
position of the optical pickup with respect to the optical disk 301
are properly maintained in combination therebetween.
[0280] Thereby, disk surface vibration along the disk rotation axis
direction or axial runout can be well controlled thanks to air flow
pressure difference according to the Bernoulli's effect at a
portion on which information recording/reproducing is performed on
the flexible optical disk. Thereby, it is possible to achieve
high-density information recording at the stabilized portion on the
optical disk. Further, even when the position along the disk radius
direction, disk rotation speed, and/or disk specification are
changed, it is possible to well control the surface vibration at a
portion on which recording/reproducing on the optical disk is
performed
[0281] Further, the present invention is not limited to the
above-described embodiments, and variations and modifications may
be made without departing from the basic concepts of the present
invention.
[0282] The present application is based on Japanese priority
applications Nos. 2001-118344, 2001-228943, 2002-18323,
2001-158663, 2001-234299 and 2001-253896, filed on Apr. 17, 2001,
Jul. 30, 2001, Jan. 28, 2002, May 28, 2001, Sep. 19, 2001 and Aug.
24, 2001, respectively, the entire contents of which are hereby
incorporated by reference.
* * * * *