JP2009070495A - Method and device for holding optical recording medium, and method and device for initializing phase transition type optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for holding an optical recording medium or the like by which warpage of an optical disk during initialization can be reduced even when the optical disk has 0.6 mm substrate thickness, the optical disk is not damaged and initialization can be efficiently performed. <P>SOLUTION: In the method for holding the optical recording medium, the disk like optical recording medium is held on a base table by at least a part of an inner peripheral region having 7.5 to 17 mm radius and at least a part of an entity region having 47 to 57 mm radius. It is preferable that the entity region has 50 to 57 mm radius and the optical recording medium is held by air suction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical recording medium holding method, an optical recording medium holding device, a phase change optical recording medium initialization method including the optical recording medium holding method, and a phase change having the optical recording medium holding device. The present invention relates to an initialization apparatus for a type optical recording medium.

A phase change optical recording medium such as a DVD + RW disk (hereinafter also referred to as “optical recording medium” or “optical disk”) is generally formed on a substrate formed by injection molding a polycarbonate resin. The phase change recording layer, the second dielectric layer, and the reflective layer are formed by sputtering, and a UV curable resin is applied on the reflective layer and cured.
The phase change recording layer formed on the substrate has a low reflectivity when laser light is incident in an amorphous state as it is, and therefore, an optical recording device is subjected to an initialization process for crystallizing the recording layer. It becomes possible to recognize. The initialization step is an essential step in the method of manufacturing a phase change optical recording medium. Such an initialization step is performed by once cooling the phase change recording layer to the melting temperature and then gradually cooling it.

  As a material for a substrate of an optical disk, polycarbonate resin is usually used from the viewpoint of stability of mechanical properties, mass, price, and the like. In this case, if the entire surface of the optical disk is initialized at the same time, the power density becomes too high and the heat resistance temperature of the polycarbonate resin may be exceeded. Therefore, as an initialization method, it is general to rotate the optical disc and irradiate a high-power laser while controlling the focus to partially promote crystallization. Specifically, the optical disk fixed at the clamp part is rotated, and the laser head or the rotating optical disk is gradually moved in the radial direction so that the longitudinal direction of the elliptical laser beam is perpendicular to the track. As a result, the entire surface of the optical disk is initialized. An initialization apparatus used for such initialization is disclosed, for example, in Patent Document 1 and the like.

  In addition, in an optical disc such as a DVD + RW having a substrate thickness of about 0.6 mm, the substrate thickness is thin, so that the warpage of the optical disc changes greatly during a partial initialization from the outer periphery to the inner periphery (or vice versa). . In the initialization process, the laser is focused on the recording layer of the optical disc, and power is applied to change the amorphous state to the crystallized state. Therefore, if the warpage of the substrate changes greatly during initialization, the focus during initialization is changed. Cannot be matched, and the probability of being defective becomes high.

Therefore, in order to reduce the change in the warp of the optical disc during initialization, a method of evenly adsorbing from the inner circumference to the outermost circumference of the optical disc has been proposed (see Patent Document 2). However, this proposal has the disadvantages that since the rotating part is large, the accuracy requirements of the initialization device are severe and expensive, and the optical disk is easily scratched.
In addition, a method of holding the optical disk at at least two locations, that is, an inner periphery and an outer periphery (see Patent Document 3). However, in this proposal, the range in which the outer peripheral portion can be held is as narrow as 60 mm−58 mm = 2 mm in radius value, and it is difficult to hold the optical disc stably, and there is a problem that warpage occurs.

  Therefore, even in the case of a thin optical disk having a substrate thickness of about 0.6 mm, the occurrence of warping during initialization can be reduced, and the optical disk can be efficiently initialized without scratching the optical disk. At present, a medium holding method and an optical recording medium holding apparatus have not yet been provided.

JP-A-10-241212 JP 2001-028156 A JP 2003-91889 A

  An object of the present invention is to solve the above-described problems and achieve the following objects. In other words, the present invention can reduce the occurrence of warping during initialization even if the substrate has a thin thickness of, for example, about 0.6 mm, and the optical disc is not damaged and can be initialized efficiently. Optical recording medium holding method and optical recording medium holding apparatus that can be performed, phase change optical recording medium initialization method including the optical recording medium holding method, and phase change having the optical recording medium holding apparatus An object of the present invention is to provide an initialization device for a type optical recording medium.

  As a result of intensive investigations by the present inventors to solve the above-mentioned problems, in the case of initializing an optical disc such as a DVD + RW having a substrate thickness of about 0.6 mm as compared with a general optical disc having a thickness of 1.2 mm. It has been found that the substrate is warped during initialization due to the influence of the heat of the laser beam, resulting in a focus error. Therefore, as a result of diligent investigations on measures on the initialization device side in order to prevent a focus error during initialization, the present inventors have determined that the radius of a disk-shaped optical recording medium is 7.5 mm or more and 17 mm. A thin optical disk having a substrate thickness of about 0.6 mm by holding on the base at least a part of the following inner peripheral area and at least a part of the substantial area having a radius of 47 mm to 57 mm. Further, the inventors have found that the occurrence of warping during initialization can be reduced, the optical disk is not damaged, the initialization can be performed efficiently, and the focus error is drastically reduced.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> A disk-shaped optical recording medium is mounted on a base with at least a part of an inner peripheral area having a radius of 7.5 mm to 17 mm and at least a part of a substantial area having a radius of 47 mm to 57 mm. An optical recording medium holding method characterized in that the optical recording medium is held in
<2> The optical recording medium holding method according to <1>, wherein the substantial region has a radius of 50 mm or greater and 57 mm or less.
<3> The method for holding an optical recording medium according to any one of <1> to <2>, wherein the holding is performed by air adsorption.
<4> a base, a disk-shaped optical recording medium on the base, at least a part of an inner peripheral region having a radius of 7.5 mm to 17 mm, and a substantial region having a radius of 47 mm to 57 mm An optical recording medium holding device having at least a holding means for adsorbing and holding the air by at least a part of the optical recording medium.
<5> The optical recording medium holding device according to <4>, wherein the substantial region has a radius of 50 mm to 57 mm.
<6> The optical recording medium holding device according to any one of <4> to <5>, wherein an air adsorbing annular groove connected to the holding unit is formed in an inner peripheral area and a substantial area of the base. It is.
<7> In any one of the above items <4> to <5>, a plurality of air adsorbing holes are formed in the substantial area of the base so as to be connected to the holding unit and spaced apart from each other at a predetermined interval on the same circumference. An optical recording medium holding device according to claim 1.
<8> A phase change optical recording medium initialization method, wherein the initialization is performed in a state of being held by the optical recording medium holding method according to any one of <1> to <3>.
<9> A phase change optical recording medium initialization apparatus comprising the optical recording medium holding apparatus according to any one of <4> to <7>.

  According to the present invention, the conventional problems can be solved, and even when the optical disk has a thickness of about 0.6 mm, the occurrence of warpage during initialization can be reduced, and the optical disk is not damaged. , Optical recording medium holding method and optical recording medium holding apparatus capable of efficient initialization, phase change optical recording medium initialization method including the optical recording medium holding method, and optical recording medium An initialization device for a phase change optical recording medium having a holding device can be provided.

(Optical recording medium holding method and optical recording medium holding apparatus)
The optical recording medium holding method according to the present invention comprises a disc-shaped optical recording medium having at least a part of an inner peripheral region having a radius of 7.5 mm to 17 mm and a substantial region having a radius of 47 mm to 57 mm. At least partly hold on the base.
The optical recording medium holding device of the present invention comprises a base, a disk-shaped optical recording medium on the base, at least a part of an inner peripheral region having a radius of 7.5 mm to 17 mm, It has at least a holding means for adsorbing and holding at least a part of the substantial area having a radius of 47 mm or more and 57 mm or less, and further has other means as necessary.
The optical recording medium holding method and optical recording medium holding apparatus of the present invention will be described below.

The inner peripheral region has a radius of 7.5 mm to 17 mm.
The substantial region has a radius of 47 mm to 57 mm, preferably 50 mm to 57 mm.
The radius of the entire disc-shaped optical recording medium is 60 mm.
The holding is performed by air adsorption, so that the optical disk can be held only on a surface different from the surface on which the optical disk is irradiated with laser light. When the substantial area is held, the optical pickup unit and the laser light are hindered. It is preferable from the point of not becoming.

It is preferable that an annular groove for air adsorption connected to the holding means is formed in each of the inner peripheral area and the substantial area of the base. The size, shape and the like of the air adsorbing annular groove are not particularly limited and can be appropriately selected according to the purpose. For example, the groove width is preferably 2.5 mm to 5.0 mm, and the groove height is 0. 0.5 mm to 1.5 mm is preferable. The cross-sectional shape of the air adsorbing annular groove is preferably a rectangular shape or a square shape, for example.
In addition, as shown in FIG. 3, the annular groove | channel for air adsorption | suction in a substantial area | region may be parted by the spacer of 7 in FIG.

It is preferable that a plurality of air adsorbing holes are formed in the substantial area of the base so as to be connected to the holding means and provided at a predetermined interval on the same circumference. As a result, it is possible to suck and hold the air suction annular groove in the inner peripheral region, and to suck and hold the air suction hole in the actual region.
There is no restriction | limiting in particular in the magnitude | size, shape, number, etc. of the said air adsorption hole, According to the objective, it can select suitably, The said size (diameter) has 1.0-2.0 mm preferable. Examples of the shape include a circle, a square, and a triangle.

Note that holding in the inner peripheral area and the substantial area of the optical disk means that the groove includes the air adsorbing annular groove and the air adsorbing hole in the area.
In the actual region, air suction holes can be provided at a predetermined interval on a plurality of air suction annular grooves or on different same circumferences.

Here, FIG. 1 is a schematic view showing an example of the optical recording medium holding device of the present invention. In FIG. 1, a base 2 for holding the optical recording medium 1 and a spindle unit 4 for rotating the base 2 are provided.
As shown in FIG. 2, the optical recording medium 1 includes an air adsorbing annular groove 3 provided in a base 2 corresponding to the inner peripheral area of the optical recording medium, and portions corresponding to the substantial area of the optical recording medium. The air suction annular groove 5 provided on the base 2 sucks air by the operation of a compressor (not shown) and is held by air suction.
Further, as shown in FIG. 4, an air adsorbing annular groove 3 provided in a base 2 corresponding to the inner peripheral area of the optical recording medium, and a base 2 corresponding to the substantial area of the optical recording medium. You may hold | maintain by air adsorption | suction with the air adsorption | suction hole 6 provided in the same circumference spaced apart by predetermined spacing.

-Optical recording medium-
The optical recording medium is not particularly limited as long as it has a phase change recording layer that needs to be initialized, and can be appropriately selected according to the purpose. However, a DVD + RW having a substrate thickness of about 0.6 mm is used. And DVD-RW are particularly preferable.
The DVD + RW information substrate is formed by molding an polycarbonate resin substrate having a groove width of 0.25 μm and a groove depth of 27 nm into a thickness of 0.6 mm using an injection molding machine.
Next, a total of five layers including a first dielectric layer, a phase change recording layer, a second dielectric layer, a reflective layer, and, if necessary, an adhesion improving layer are sequentially formed on the substrate by a sputtering method. Form.
Examples of the dielectric layer include a ZnS · SiO ₂ layer. Examples of the phase change recording layer include a Ge—Ag—In—Sb—Te layer. Examples of the adhesion improving layer include a SiC layer. Examples of the reflective layer include Ag and an Ag alloy.

The thickness of the first dielectric layer is preferably 50 nm to 120 nm. The thickness of the phase change recording layer is preferably 12 nm to 35 nm. The thickness of the second dielectric layer is preferably 6 nm to 30 nm. The thickness of the adhesion improving layer is preferably 1 nm to 12 nm. The thickness of the reflective layer is preferably 80 nm to 200 nm.
The optical disk that has been sputtered is coated with a UV curable resin on the reflective layer and cured by irradiating with ultraviolet rays. Further, if necessary, a resin is also applied to the laser incident side (the polycarbonate resin substrate side) and UV cured. The obtained optical disk is irradiated with a laser beam for initialization.

As a cover substrate to be bonded to the resin application side in DVD + RW, a polycarbonate resin substrate having a guide groove having a groove width of 0.25 μm and a groove depth of 27 nm is first formed to a thickness of 0.6 mm by an injection molding machine.
A DVD + RW disc is completed by bonding the produced information substrate and a cover substrate together.
As the bonding method, for example, a method using a hot melt adhesive and a method using a cationic polymerization UV curable resin are generally used, and the thickness of the bonding layer is preferably 10 μm to 100 μm.

(Phase change optical recording medium initialization method and phase change optical recording medium initialization apparatus)
The initialization method of the phase change optical recording medium of the present invention initializes the phase change optical recording medium held by the optical recording medium holding method of the present invention.
An initialization apparatus for a phase change optical recording medium according to the present invention includes the optical recording medium holding apparatus according to the present invention, and further includes other means as necessary.

Here, FIG. 5 is a schematic diagram showing an example of the phase change optical recording medium initialization apparatus 100 of the present invention. This initialization apparatus 100 is an optical pickup that enables automatic focus control including a base 16 that holds the optical disc 1, a spindle unit 12 that rotates the base 16, and an objective lens 15 for shaping semiconductor laser light. Section 13 and feeding means 14 for displacing the optical pickup section 13 in the radial direction of the optical disc 1.
By providing an elastic body capable of air permeation (for example, a polymer polyethylene porous sheet or paper) on the upper surface of the base 16, damage and deformation of the optical disk when the optical disk 1 is adsorbed to the base are alleviated. be able to.

  As a method of initializing the optical disc 1 using the initialization device, the optical disc 1 is placed on the base 16 by an automatic transport device or a robot. Then, the optical disk 1 is sucked by sucking air from the air suction groove or the air suction hole as the holding means, and the optical disk 1 is flattened by this suction force. In this state, the optical disk 1 is rotated by the spindle unit 12. The recording layer is initialized by focusing the laser beam 15 irradiated from the optical pickup unit 13 on the recording layer of the rotating optical disc 1. During this initialization, the optical disc 1 tends to be deformed, but since the base 16 adsorbs and holds the optical disc 1 to suppress the deformation, the laser beam 5 is not aligned with the recording layer. The in-focus state is accurately maintained, and uniform initialization can be stably performed over the entire surface of the optical disc 1.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

-Production of optical recording media-
A first dielectric layer made of (ZnS) _70. (SiO ₂ ) ₃₀ on a substrate made of polycarbonate resin having a diameter of 12 cm, a thickness of 0.6 mm, a pitch of 0.4 μm on the surface, and an uneven guide groove having a groove depth of 20 nm. (Thickness 120 nm), phase change recording layer (thickness 6 nm) made of Ge—Ag—In—Sb—Te, second dielectric layer (thickness 15 nm) made of (ZnS) _70. (SiO ₂ ) ₃₀ , and Ag In the order of the reflection layers (thickness 140 nm), films were formed by sputtering in an Ar gas atmosphere using a sputtering apparatus.
Next, an acrylic ultraviolet curable resin was applied by a spin coating method so as to have a thickness of 5 μm to 10 μm, and cured with ultraviolet rays to form an organic protective layer. Thus, an optical disc having a thickness of about 0.6 mm was produced.

Example 1
Using the optical recording medium holding device as shown in FIG. 1, the produced optical disk is divided into an inner peripheral region having a radius of 7.5 mm to 17 mm and a substantial region having a radius of 47 mm to 57 mm. As shown in FIG. 2, the air suction annular grooves 3 and 5 provided on the base 2 were held by air suction, and initialization was performed under the conditions of a linear speed of 10 m / sec, a power of 1000 mW, and a head feed of 37 μm. The groove width of the air adsorbing annular groove was 3.0 mm.

(Example 2)
Using the optical recording medium holding device as shown in FIG. 1, the produced optical disk is divided into an inner peripheral region having a radius of 7.5 mm to 17 mm and a substantial region having a radius of 52 mm to 57 mm. As shown in FIG. 2, the air suction annular grooves 3 and 5 provided on the base 2 were held by air suction, and initialization was performed under the conditions of a linear speed of 10 m / sec, a power of 1000 mW, and a head feed of 37 μm. The groove width of the air adsorbing annular groove was 3.0 mm.

(Example 3)
In Example 1, the manufactured optical disk was the same as Example 1 except that the air suction ring groove 3 provided on the base 2 and the air suction hole 6 were held by air suction as shown in FIG. Was initialized.
The groove width of the air adsorption annular groove was 3.0 mm, and the diameter of the air adsorption hole was 1.5 mm.

(Comparative Example 1)
The produced optical disk was sucked and held by a number of air suction holes provided uniformly from the inner periphery to the outer periphery of the base 2 and initialized under the conditions of a linear speed of 10 m / sec, a power of 1000 mW, and a head feed of 37 μm. The diameter of the air suction hole was 1.5 mm.

(Comparative Example 2)
Using the optical recording medium holding device as shown in FIG. 6, the produced optical disk is sucked and held by the air suction annular groove 3 only in the inner peripheral area having a radius of 7.5 mm or more and 17 mm or less. Initialization was performed under the conditions of / sec, power of 1000 mW, and head feed of 37 μm. The groove width of the air adsorbing annular groove was 6.0 mm.

  Next, for each of the optical disks of Examples 1 to 3 and Comparative Examples 1 and 2, the warpage amount, the degree of scratching, and the PI error were evaluated as follows. The results are shown in Table 1.

<Measurement of warpage>
The amount of warpage was measured by measuring the warpage of the optical disk before and after initialization using a mechanical property evaluation apparatus, and evaluating the amount of change in warpage due to initialization. “+” Indicates that the warp is upward.

<Evaluation of scratches on optical disc>
The appearance of each optical disk after initialization was evaluated visually and using a microscope to evaluate the degree of scratches on the optical disk.

<Evaluation of PI error>
Using the evaluation device, the entire optical disk after initialization was written and the PI error was evaluated.

The optical recording medium holding method of the present invention and the optical recording medium holding apparatus of the present invention can suppress the deformation of the disk during initialization, reduce the focus error, and prevent the optical disk from being damaged. It can be suitably used for initialization of a changeable optical recording medium.
The phase change optical recording medium initialization method of the present invention and the phase change optical recording medium initialization apparatus of the present invention use the optical recording medium holding method of the present invention and the optical recording medium holding device of the present invention. Therefore, it is suitable for initialization of optical recording media such as DVD + RW, DVD-R, etc., which have a thin substrate thickness of about 0.6 mm.

FIG. 1 is a schematic view showing an example of an optical recording medium holding device of the present invention. FIG. 2 is a plan view showing an example of the optical recording medium holding device of the present invention. FIG. 3 is a plan view showing another example of the optical recording medium holding device of the present invention. FIG. 4 is a plan view showing still another example of the optical recording medium holding device of the present invention. FIG. 5 is a schematic view showing an example of the initialization apparatus of the present invention having the optical recording medium holding apparatus of the present invention. FIG. 6 is a schematic view showing an example of a conventional optical recording medium holding device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2 Base 3 Air adsorption | suction annular groove of inner peripheral area | region 4 Spindle part 5 Air adsorption | suction groove | channel of substantial area | region 6 Air adsorption hole of substantial area | region 7 Spindle part 13 Spindle part 13 Optical pick-up part 14 Feed means 15 Objective lens 16 Base 100 Phase change type optical recording medium initialization device

Claims (9)

  A disk-shaped optical recording medium is held on a base by at least a part of an inner peripheral area having a radius of 7.5 mm to 17 mm and at least a part of a substantial area having a radius of 47 mm to 57 mm. A method for holding an optical recording medium.   The method for holding an optical recording medium according to claim 1, wherein the substantial area has a radius of 50 mm to 57 mm.   The method for holding an optical recording medium according to claim 1, wherein the holding is performed by air adsorption.   A base, and a disk-shaped optical recording medium on the base, at least a part of an inner peripheral region having a radius of 7.5 mm to 17 mm, and at least one of a substantial region having a radius of 47 mm to 57 mm. An optical recording medium holding apparatus, comprising: a holding unit that holds and holds the air by adsorbing the air to the unit.   The optical recording medium holding device according to claim 4, wherein the substantial area has a radius of 50 mm to 57 mm.   6. The optical recording medium holding device according to claim 4, wherein an air adsorbing annular groove connected to the holding means is formed in each of an inner peripheral area and a substantial area of the base.   6. The optical recording according to claim 4, wherein a plurality of air adsorbing holes are formed in a substantial area of the base so as to be connected to the holding means and provided at a predetermined interval on the same circumference. Media holding device.   4. An initialization method for a phase change optical recording medium, wherein the initialization is performed while being held by the holding method for an optical recording medium according to claim 1.   An initialization apparatus for a phase change optical recording medium, comprising the optical recording medium holding apparatus according to claim 4.

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