JPH10188459A - Optical disk device, and optical disk recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To pertinently perform recording and/or reproducing processing in accordance with the thickness of a substrate, by detecting a physical mark formed on the surface of a cartridge with a thickness detecting means and controlling the recording and/or reproducing mode for an optical disk in accordance with the above detecting with a control means. SOLUTION: The physical mark showing the thickness of a transparent substrate is detected from the surface of a disk cartridge 1 by a thickness detector consisting of a detecting part 30a and a contractor 30b. The changeover control of the recording and/or reproducing mode is performed on a magneto- optical disk 2 by a system controller 29 in accordance with a detecting output from this thickens detector. In accordance with this detecting output, two objective lenses 11 and 12 installed in an optical head 10 are also changeover- controlled. The physical mark provided on the cartridge surface is a hole part, a reflecting part or a projecting object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus and an optical disk recording medium for recording and / or reproducing information signals by irradiating a recording layer of an optical disk housed in a cartridge with light through a transparent substrate.

[0002]

2. Description of the Related Art In an optical recording medium such as an optical disk, an information signal is recorded and / or reproduced by a laser beam irradiated on a recording layer via an optically transparent substrate made of, for example, polycarbonate. This optical recording medium has been widely spread as a recording medium for computers, package media such as audio and video, and has also been increasing in density.

As one method of increasing the density, it is conceivable to increase the numerical aperture NA of the objective lens. This is because the beam spot formed on the optical recording medium is small and the resolution is improved. However, if the NA is increased, the allowable range with respect to the tilt of the disk becomes narrow.

[0004] Therefore, it has been considered to make the substrate thinner. For example, the substrate of a magneto-optical disk having a diameter of 5.25 inches is 1.2 mm at present, but it is conceivable to reduce this by half to 0.6 mm. If the substrate is made thinner, a margin of error with respect to the inclination of the disk can be obtained to some extent even when the NA is increased.

For this reason, as described above, the substrate is 1.2 m
There has been a demand for an optical disk device capable of recording / reproducing information signals for both a magneto-optical disk of m and a magneto-optical disk of 0.6 mm.

[0006]

As described above, in the case where a magneto-optical disk having a substrate thickness of 0.6 mm is used to increase the recording density, a magneto-optical disk having a current 1.2 mm-thick substrate is used. It is necessary to be compatible with the disk, but for a magneto-optical disk with a diameter of 5.25 inches,
The above-described optical disk device having a function of determining the thickness has not been considered.

A magneto-optical disk having a diameter of 5.25 inches is conventionally housed in a disk cartridge, but does not have a mechanism for determining the thickness.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is directed to an optical disk apparatus having a function of determining the substrate thickness of an optical disk and capable of performing appropriate recording and / or reproducing processing according to the substrate thickness. For the purpose of providing.

Another object of the present invention is to provide an optical disk recording medium having a mechanism suitable for determining the thickness of a substrate.

[0010]

In order to solve the above-mentioned problems, an optical disk apparatus according to the present invention detects a physical mark formed on the surface of a cartridge by a thickness detecting means and outputs the detected output to a control means by the control means. The switching of the recording and / or reproduction mode for the optical disk is controlled accordingly.

In order to solve the above-mentioned problems, the optical disk recording medium according to the present invention is provided with a physical marking for judging the thickness of the transparent substrate on the cartridge housing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magneto-optical disk device as an embodiment of an optical disk device according to the present invention and a magneto-optical disk as an embodiment of an optical disk recording medium will be described with reference to the drawings.

The magneto-optical disk drive irradiates a recording layer of, for example, a 5.25 inch diameter magneto-optical disk accommodated in a cartridge with a laser beam through a transparent substrate made of, for example, polycarbonate to record and / or record information signals. Or regenerate.

As shown in FIG. 1, the magneto-optical disk device has a thickness detector 30 for detecting a physical mark indicating the thickness of the transparent substrate from the surface of the disk cartridge 1,
A system controller 29 is provided for switching between recording and / or reproducing modes for the magneto-optical disk 2 in accordance with the detection output from the thickness detector 30. here,
The disk cartridge 1 accommodating the magneto-optical disk 2 is an embodiment of the optical disk recording medium.

As shown in FIGS. 2 and 3, the disk cartridge 1 has one surface (hereinafter referred to as a surface) 2.
_The magneto-optical disk 2 to which _A and the other surface (hereinafter referred to as the back surface) _2B are bonded is rotatably housed inside. FIG. 2 shows the front side of the disc cartridge 1.
FIG. 3 shows the back surface. When this disk cartridge is inserted into a cartridge holder (not shown) of the magneto-optical disk device while looking at "A" shown on the front surface, the shutter 7 is opened by a shutter opening / closing mechanism (not shown) of the device and the shutter 7 is opened. Parts _4A and _4B are exposed. When the shutter is completely opened, that is, when the disk cartridge 1 is completely housed in the cartridge holder, the mounting of the disk cartridge 1 in the apparatus is completed.

At this time, the hub 3 _A on the A surface 2 _A side of the magneto-optical disk 2 covered by the shutter 7 on the back side of the disk cartridge 1 is connected to the motor shaft of the spindle motor 28 through the through hole 6 _A. The magneto-optical disk 2 is mounted on a spindle motor 28 in close contact with and held by a turntable 31 with a magnet provided at the upper end.

[0017] In this state, the A side 2 of the magneto-optical disk 2_A
And / or reproduction of the magneto-optical disk device on the side
Becomes possible. That is, in the direction of the arrow shown in FIG.
With the “A” facing up, insert the disk cartridge 1
When inserted into the cartridge holder, it is actually shown in FIG.
Opening 4_AA side 2 on the side_AIs exposed.

On the other hand, when this disk cartridge 1 is inserted into the cartridge holder of the magneto-optical disk device in the direction of the arrow while looking at "B" shown on the back surface, the shutter 7 is opened by the shutter opening / closing mechanism, and the shutter 7 is opened. Part 4 _A
And 4 _B are exposed, but this time, the hub 3 _B of B surface 2 _B side of the magneto-optical disc 2 which was covered with the shutter 7 on the surface side of the disk cartridge 1, the spindle motor via a hole 6 _B The magneto-optical disk 2 is mounted on a spindle motor 28 in close contact with and held by a turntable 31 with a magnet provided at the upper end of a motor shaft 28.

In this state, the B surface 2 _{B of the} magneto-optical disk 2
The recording and / or reproduction of the magneto-optical disk device can be performed on the side. That is, when the disk cartridge 1 is inserted into the disk cartridge holder in the top "B" in the direction of the arrow shown in FIG. 3, it is actually exposed surface B 2 _B in the opening 4 _B side shown in FIG. 2 .

The magneto-optical disk 2 has A-side surfaces 2 _A and B
Forming a surface 2 _B as shown in FIG. That is, for example, on a transparent substrate 61 made of polycarbonate, a dielectric layer 62 made of a SiN film and an MO layer 6 made of TbFeCo
3. A dielectric layer 64, a reflective film 65 made of Al, and a protective film 66 made of UV resin are formed. Then, the protective films 66 are bonded together to form a bonded disk.

As shown in FIG. 1, when the disk cartridge 1 is inserted into the disk cartridge holder of the magneto-optical disk drive in the direction of the arrow while looking at "A" as described above, the A surface 2 of the magneto-optical disk 2 laser light is irradiated from the optical head 10 to the _a side through the opening 4 _a.

The optical head 10 has two objective lenses 11
, 12, a two-axis unit 13 for switchably holding the two objective lenses 11 and 12, a mirror 14, and a fixed optical system 15.

The objective lens 11 can record and / or reproduce information signals optimally on a magneto-optical disk having a numerical aperture NA of, for example, 0.6 and a transparent substrate 61 of 0.6 mm. On the other hand, the objective lens 12 has a numerical aperture N
It is possible to optimally record and / or reproduce information signals on a magneto-optical disk in which A is set to 0.55 and the transparent substrate 61 is set to 1.2 mm, for example.

As shown in FIG. 5, the fixed optical system 15 includes a laser diode 16 for diffusing and emitting a writing laser beam or a reproducing laser beam, a collimator lens 17 for parallelizing these laser beams, A beam splitter 18 that transmits the laser light in the direction of the mirror 14 and reflects return light, which will be described later, and changes a Kerr rotation angle of the return light reflected by the reflection surface 18a of the beam splitter 18 into a light intensity change. A polarization beam splitter 19, a photodiode 20 that converts one return light transmitted through the polarization beam splitter 19 into an electric signal, and converts the other return light reflected by the reflection surface 19a of the polarization beam splitter 19 into an electric signal. Photodiode 21 to convert
And

For example, when an information signal is recorded on the _A side _2A side, a system controller 29 drives a laser driver 32 to write a laser beam to the laser diode 16 in the fixed optical system 15 of the optical head 10. Supply drive current. At this time, the magnetic head driver 33 supplies a drive current for giving magnetization in a certain direction to the magnetic head 34 composed of an electromagnet.

In the initial state, the direction of magnetization of the MO film 63 is, for example, downward. Here, an upward magnetic field is applied from the outside by the magnetic head 34, and the optical head 10 irradiates a writing laser beam at the timing of recording the information signal. Become warm point the writing laser beam A surface 2 _A side MO film 63 of the magneto-optical disc 2 hits found
When the Curie point is reached, the coercive force of the MO film 63 decreases, and a portion where the magnetization is reversed upward due to the action of the external magnetic field by the magnetic head 34 is formed, and an information signal is recorded.

When reproducing information from the magneto-optical disk, the laser diode 16 of the optical head 10
System controller 29 via laser driver 32
And emits a laser beam for reproduction.

The laser beam for reproduction is irradiated onto the MO layer through the transparent substrate 61. The laser beam for reproduction that has entered the MO layer 63 is reflected so that the plane of polarization slightly rotates by about 0.2 to 0.4 degrees depending on the direction of magnetization, and becomes return light. This return light passes through the objective lens 11 or the objective lens 12, is reflected by the mirror 14, and is reflected by the fixed optical system 1.
Return to 5. In the fixed optical system 15, the change in the Kerr rotation angle (± θ) of the return light is converted into a light intensity change by the polarization beam splitter 19, and guided to the photodetectors 20 and 21.
Take it out as an electrical signal.

The electric signals detected by the photo detectors 20 and 21 of the fixed optical system 15 are supplied to a matrix circuit 23. The matrix circuit 23 is constituted by, for example, a digital signal processing unit (DSP).
An F signal is generated and supplied to the output terminal 35. The matrix circuit 23 generates a focus servo signal and a tracking servo signal from the focus error signal and the tracking error signal, and
And the tracking driver 25. In addition, a thread servo signal and a spindle servo signal are generated and supplied to the thread driver 26 and the spindle driver 27.

The focus driver 24 supplies a drive current to the focus coil of the biaxial unit 13 according to the focus servo signal, and drives the objective lens 11 or 12 in the focus direction, that is, in a direction parallel to the optical axis. The tracking driver 25 supplies a drive current to the tracking coil of the biaxial unit 13 according to the tracking servo signal, and drives the objective lens 11 or 12 in the track direction, that is, in a plane direction orthogonal to the optical axis.

The thread driver 26 drives the biaxial portion 13 largely in a plane direction orthogonal to the optical axis according to the thread servo signal. Spindle servo driver 27
Drives the spindle motor 28 to rotate at CAV or CLV according to the spindle servo signal. Such servo processing is performed not only at the time of the reproduction processing but also at the time of the recording processing.

[0032] the disc cartridge 1, as shown in FIGS. 2 and 3, like the media identification hole group 9 with respect to the surface A 2 _A side-erase prevention hole 8 erroneous for A face 2 _A side, B side 2 _B-side A medium identification hole group 11 for the _B side 2B side is provided in the same manner as the erroneous erasure prevention hole 10 for. The media identification hole group 9 includes, for example, four hole identification holes 9 ₁ , 9 ₂ , 5 _A, and 9 ₄ as shown in FIG. Currently the first in the standard
Identity holes 9 ₁ has been used to identify the high and low reflectivity of the disk, when closed the low reflectance, shows a high reflectance when the open. Also, the second
Identity holes 9 ₂ are used accessible disk side.

[0033] Here, the third discrimination hole 5 _A and fourth identification hole 9 ₄ now, because it is undefined, for example, the third identification hole 5 _A so as to identify the thickness of the transparent substrate Defined in At present, a transparent substrate of 1.2 mm is mainly used. Therefore, when the substrate is closed, the transparent substrate has a thickness of 1.2 mm, and when it is open, the transparent substrate has a thickness of 0.6 mm. Fourth identification hole 9 ₄
May be defined in this manner.

[0034] FIG. 1 shows an example of using the third discrimination hole 5 _A for identification of the thickness of the transparent substrate. Similarly B surface 2 also media identification hole group 11 of the _B side using the third discrimination hole 5 _B for the transparent substrate thickness identified. FIG. 1 shows a third identification hole 5.
And _A, showed only the detection portion 30a and the thickness detector 30 consisting of contacts 30b, in practice, other three identification holes 9 _1, 9 also ₂ and 9 ₄ provided as shown in FIG. 6 ing. Detectors 40, 41, and 42 that detect opening and closing of each hole and detect the identification of the medium also include detection units 40a and 40a, respectively.
Along with 41a and 42a and contacts 40b, 41b and 42b, they are arranged on the device side so as to correspond to the positions where the respective identification holes are provided. Here, each contact is configured to protrude toward each identification hole by, for example, an elastic body. The detection results of the detectors 40, 41, 30, and 42 are supplied to the system controller 29.

The third identification hole 5 _A shown in FIG. 1, since they are open, contacts 30b of thickness detector 30 protrudes upwardly, entering the discrimination hole 5 _A. At this time, the detection unit 30 _A outputs an ON signal (high level signal) to the system controller 29.

The system controller 29, the detection result from the thickness detector 30 is on signal, to determine the thickness of the transparent substrate of the optical disk A surface 2 _A is 0.6 mm, transparent The objective lens 11 having a numerical aperture NA (= 0.6) suitable for a magneto-optical disk having a substrate thickness of 0.6 mm is selected and set on the biaxial portion 13.

[0037] If the thickness detection result from the detector 30 is an OFF signal, the system controller 29, the thickness of the transparent substrate of the optical disk A surface 2 _A is not the 0.6 mm,
For example, it is determined that the thickness of the transparent substrate is 1.2 mm.
Numerical aperture NA (= 0.5) suitable for a 2 mm magneto-optical disk
The objective lens 12 provided with 5) is selected and set on the biaxial portion 13.

Here, the thickness detector 30 has its detection unit 3
0a and the contact 30b are configured as shown in FIG. When the contact 30b protrudes to the third discrimination hole 5 _A, the light from the light emitting diode 45 is received by the light receiving portion 46 without being cut off, the output signal (high level signal) is supplied to the system controller 29 You.

As shown in FIG. 8, the detection switch 30 may comprise a detection section 30a and a contact 30b. When the contact 30b protrudes to the identification hole 5 _A, apart movable contact portion 48 from the fixed contact portion 49, the output signal (low level signal in this case) the system controller 2
9. The setting of the system controller 29 has been changed so that when the level is low, the transparent substrate thickness is determined to be 0.6 mm.

Further, the detection switch 30 may be configured as shown in FIG. The detecting unit 51 includes the light emitting unit 5
2 and the light receiving unit 53, but the light receiving unit 53 cannot directly receive the light from the light emitting unit 52. In the case where the thickness of the transparent substrate is 0.6 mm, if the reflective seal 50 is attached to a position different from the media identification hole groups 9 and 11 on the disk cartridge 1, the detecting section 51 will be reflected by the reflective seal 50. The light from the light emitting unit 52 is
Therefore, an output signal (high-level signal) can be supplied to the system controller 29. When the thickness of the transparent substrate is 1.2 mm, the detecting section 51 cannot supply a high-level output signal to the system controller 29 because the reflective seal 50 is not attached on the disk cartridge 1.

Next, the control performed by the system controller 29 is shown in the flowchart of FIG. 10, and the operation of the magneto-optical disk device will be described with reference to FIG.

First, when the disk cartridge 1 is inserted into the disk cartridge holder in the apparatus in step S1, the transparent substrate thickness t is 0.6 mm according to the detection result from the thickness detector 30 in step S2. It is determined whether or not.

If the thickness of the transparent substrate is 0.6 mm, the flow advances to step S3 to select the objective lens 11 having a numerical aperture NA (= 0.6) for the thickness t = 0.6 mm of the transparent substrate. It is set on the biaxial part 13 and set on the optical path.

Then, in step S4, the spindle motor 28 is turned on, the laser diode 16 is turned on, and the focus driver 24 is turned on. In step S5, the S written on the outer peripheral side or the inner peripheral side of the magneto-optical disk 2, for example, is written.
An FP (Standered Formatted Part) is read, and in step S6, for example, a modulation method, a sector length, a rotation speed, a reflectance, a reading laser power, an AGC, a writing laser power, etc. are adjusted in accordance with a magneto-optical disk having a transparent substrate thickness t = 0.6 mm. Set the processing state of.

When the setting of the recording and / or reproducing mode for the transparent substrate thickness t = 0.6 mm is completed as described above, the system controller 29 controls each part shown in FIG. 1 and performs the recording and / or reproducing in step S11. To start.

On the other hand, if it is determined in step S2 that the thickness of the transparent substrate is not t = 0.6 mm from the detection result from the thickness detector 30, it is determined that a magneto-optical disk with t = 1.2 mm is mounted. Then, in step S7, the objective lens 12 for t = 1.2 mm is selected and set on the optical path.

Then, in step S8, the spindle motor 28 is turned on, the laser diode 16 is turned on, and the focus driver 24 is turned on.
Is read, and in step S10, the transparent substrate thickness t = 1.2 m
m, the modulation method, the sector length, the number of rotations, the reflectance, the reading laser power, the AG
C, the processing state such as the writing laser power is set.

When the setting of the recording and / or reproducing mode for the transparent substrate thickness t = 1.2 mm is completed as described above, the system controller 29 controls the components shown in FIG. 1 to start recording and / or reproducing. .

In the magneto-optical disk drive according to the embodiment of the present invention, recording and recording of information signals are performed on a disk cartridge 1 in which two 5.25 inch magneto-optical disks are stuck and rotatably housed. Although the recording / reproduction is performed, the recording and / or reproduction of the information signal may be performed on a disk cartridge in which only one 3.5-inch or 5.25-inch magneto-optical disk is rotatably stored.

As a physical mark for identifying the thickness of the transparent substrate, a projection may be provided on the surface of the cartridge.
Further, the means for detecting the thickness is not limited to the specific examples shown in FIGS.

[0051]

According to the optical disc apparatus of the present invention, the thickness detecting means detects a physical mark formed on the surface of the cartridge, and the control means switches the recording and / or reproducing mode for the optical disc according to the detected output. Therefore, appropriate recording and / or reproduction processing can be performed according to the substrate thickness of the optical disk.

The optical disk recording medium according to the present invention is provided with a physical marking for determining the thickness of the transparent substrate in the cartridge housing, so that the apparatus can easily determine the substrate thickness. .

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of an optical disk device of the present invention.

FIG. 2 is an external view of one surface side of the embodiment of the optical disk recording medium of the present invention.

FIG. 3 is an external view of the other surface side of the embodiment of the optical disc recording medium of the present invention.

FIG. 4 is a sectional view of a disk stored in the embodiment of the optical disk recording medium.

FIG. 5 is a detailed configuration diagram of a fixed optical system used in the embodiment shown in FIG. 1;

FIG. 6 is a sectional view of a sensor hole group 9 provided on one surface side of the embodiment of the optical disk recording medium shown in FIG. 2;

FIG. 7 is a diagram showing a first specific example of a detection switch used in the embodiment shown in FIG. 1;

FIG. 8 is a diagram showing a second specific example of the detection switch used in the embodiment shown in FIG. 1;

FIG. 9 is a diagram showing a third specific example of the detection switch used in the embodiment shown in FIG. 1;

FIG. 10 is a flowchart for explaining the operation of the embodiment shown in FIG. 1;

[Explanation of symbols]

1 disk cartridge, 2 magneto-optical disk, 2 _A
Front, _2B back, 30 Thickness detection switch, 10
Optical head, 13 Biaxial part, 15 Fixed optical system, 29
System controller

Claims (4)

[Claims] 1. An optical disc device for irradiating a recording layer of an optical disc housed in a cartridge with light through a transparent substrate to record and / or reproduce information signals, wherein a physical mark indicating the thickness of the transparent substrate is provided. An optical disc device, comprising: a thickness detecting means for detecting the pressure from the surface of the cartridge; and a control means for controlling switching of a recording and / or reproducing mode for the optical disc in accordance with a detection output from the thickness detecting means. . 2. The apparatus according to claim 1, wherein said thickness detecting means detects the thickness of said transparent substrate by means of a hole, a reflection part or a projection formed on a surface of said cartridge.
An optical disk device as described in the above. 3. An optical disk recording medium comprising a cartridge housing provided with physical markings for determining the thickness of a transparent substrate. 4. The optical disk recording medium according to claim 3, wherein the physical marking is a hole, a reflection, or a protrusion.