JP2942325B2 - Optical disk warpage correcting member and optical disk inspection method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a warp correcting member for an optical disk and an inspection method of an optical disk using the same, and more particularly, to an optical disk having a configuration in which a pair of substrates are bonded or a substrate and a protection. The present invention relates to a member for correcting a warp of a substrate and a method of performing an inspection using the same before an optical disk having a configuration in which a substrate and a substrate are bonded, before bonding the substrate or the protection substrate, that is, at the time of inspection in a single plate state.

<Prior Art> Among optical discs, an optical recording disc has a configuration in which a recording layer as an information carrying unit is provided on a substrate.
Reproduction is usually performed by irradiating a laser beam or the like through a substrate.

For this reason, the substrate is made of a transparent material such as resin or glass.

The double-sided recording type optical recording disk has a configuration in which a pair of substrates each having a recording layer is bonded and integrated so that the recording layer is enclosed.

In addition, the single-sided recording type optical recording disk was bonded and integrated so that the recording layer was enclosed so as to prevent damage to the recording layer due to cracking and the like and to secure rigidity. You usually have a configuration.

With these optical recording disks, weight reduction of the disk,
A resin substrate is often used in terms of tracking groups and ease of pit formation.

By the way, when mass-producing such a double-sided recording type or single-sided recording type optical recording disk, it is necessary to measure various characteristics before bonding the substrates or bonding the substrate and the protection substrate. Occurs.

Specifically, for example, when the recording layer is formed by a vapor deposition method such as a sputtering method, when the recording layer is continuously formed,
Since the film thickness, composition, basic physical properties, and the like of the recording layer may change slightly, it is necessary to extract a sample every fixed amount and measure the characteristics of the recording layer. If the measured values deviate from the reference values, it may be necessary to correct the manufacturing conditions.

In such a case, it is preferable to perform measurement by bonding a substrate or a protective substrate to the extracted sample, since the inspection can be performed in an actual use state. However, since bonding takes time,
Quick feedback to the film formation process becomes impossible.

For this reason, the inspection is usually performed in a state where the substrate and the protective substrate are not bonded, that is, in a single plate state. However, the substrate, particularly the resin substrate, may be warped. Such a warp can be almost corrected by bonding the substrate and the protection substrate,
In the single-plate state, accurate inspection is impossible, and when the warpage is large, the inspection itself may be impossible.

To simply correct the warpage of the substrate, for example, the substrate may be pressed from both sides with a rigid disk having a flat surface, but when measuring various characteristics, it is necessary to irradiate recording light or reproduction light. However, such disks cannot be arranged on both sides of the substrate. In this case, even if the disk is transparent such as glass, accurate measurement becomes impossible.

In addition, it is conceivable to bond the surface on the side opposite to the light incident side to the rigid disk. However, in this case, it takes time for bonding, and the sample after inspection cannot be commercialized. Further, this method cannot be applied to the correction of warpage of an optical disk after commercialization.

Under such circumstances, there is a demand for a means that can correct the warpage of the substrate of the optical recording disk in a single state, and that can perform recording and reproduction while correcting the warp.

Further, not only the inspection of the optical recording disk in a single plate state, but also an optical disk using only one resin substrate such as a compact disk, a similar means is desired to correct the warpage during use.

<Problems to be Solved by the Invention> The present invention provides a warp correcting member for an optical disk that can correct the warp of an optical disk and enables recording and reproduction in a state where the warp has been corrected, and quickly and accurately by using the member. And a method capable of inspecting an optical disc.

<Means for Solving the Problems> Such an object is achieved by the present invention of the following (1) to (3).

(1) A member for correcting a warp of a single-plate optical disk having an information carrying portion on a substrate, having a sheet-like elastic body on a rigid substrate, wherein the sheet-like elastic body is made of rubber. The rubber, in a rubber indentation hardness test with a durometer specified in ASTM D 2240, the hardness of the durometer indicated in the range of 10 to 100, the surface of the sheet-like elastic body Center line average roughness Ra is 1μ
m or more and less than 50 μm, wherein the warp of the optical disc is corrected by bringing the surface of the sheet-like elastic body into close contact with the optical disc surface.

(2) The optical disk warp correcting member according to (1), wherein the rigid base is made of glass, metal, or ceramic.

(3) An optical disc having a configuration in which a pair of substrates each having an information carrying portion is bonded or an optical disc having a configuration in which a substrate having an information carrying portion and a protection substrate are bonded to a single plate before the substrate or the protection substrate is bonded A method of inspecting in a state, wherein the surface of the sheet-like elastic body of the optical disk warp correcting member according to the above (1) or (2) is brought into close contact with the surface of an optical disk in a single-plate state to correct the warp. An inspection method for an optical disk, wherein the inspection is performed by using the following method.

<Operation> The optical disk warp correcting member of the present invention is used for correcting the warp of an optical disk having an information carrying portion on a substrate, and has a configuration in which a sheet-like elastic body is provided on a rigid base material. When pressure is applied by bringing the surface of the optical disk into contact with the surface of the sheet-like elastic body, the sheet-like elastic body is elastically deformed. The warp is corrected to the same degree as the rigid base material.

In the present invention, since the warp is corrected by such an action, it is possible to correct even if the surface of the optical disk is warped convexly or concavely.

Since there is nothing on the optical disk surface opposite to the sheet-like elastic body, recording light and reproduction light can be radiated as usual.

Therefore, according to the present invention, after correcting the warp of the optical disk, recording / reproducing for various inspections and normal recording / reproducing are performed.
Reproduction can be performed.

For this reason, the optical disk warp correcting member of the present invention can be used in an intermediate stage of manufacturing an optical disk in which two substrates each having an information carrying portion are bonded or an optical disk in which a substrate having an information carrying portion and a protective plate are bonded. This is useful when performing various inspections in a single state. Then, since the single-plate optical disk can be easily peeled off from the correction member without deteriorating the characteristics, the single-plate optical disk after inspection can be commercialized by bonding to a substrate or a protection substrate.

The warp correcting member for an optical disk of the present invention is used for correcting the warpage of a read-only optical disk such as a laser disk having a configuration in which two substrates are bonded, as well as an optical recording disk such as a magneto-optical recording disk. Can also be applied.

In addition, it is not limited to a single-plate optical disk in such an intermediate stage of manufacturing, but is also used to correct warpage when using various optical recording disks having a single-plate configuration or a read-only optical disk having a single-plate configuration such as a compact disk. The present invention is useful.

<Specific Configuration> Hereinafter, a specific configuration of the present invention will be described in detail.

FIG. 1 shows a preferred embodiment of a warp correcting member for an optical disk according to the present invention.

In FIG. 1, an optical disk warp correcting member 1 has a sheet-like elastic body 3 on a rigid base 2, and the rigid base 2 and the sheet-like elastic body 3 are adhered by a double-sided adhesive tape 4.

The optical disk is warped by being in close contact with the surface of the sheet-shaped elastic body 3.

The rigid substrate 2 receives stress when correcting the warp of the optical disk. Therefore, the rigid base material 2 needs to have such rigidity that the stress does not substantially cause deformation.

The material and dimensions of the rigid base material 2 may be appropriately determined as long as such rigidity can be ensured, and are not particularly limited.

For example, examples of the constituent material include glass, various metals, and various ceramics.

However, when performing various inspections at the intermediate stage of production or when the user uses the product after commercialization, the warp correction member is loaded into the drive device and driven in a state integrated with the optical disk, so that a load is applied to the drive device. It is preferable to select a lightweight material so as not to apply too much. Examples of such a material include glass, Al, Ti, Al alloy, various ceramics, and reinforced plastic.

The shape of the rigid base material 2 is preferably a disk shape having a center hole like the optical disk to be corrected, and the diameter thereof is preferably about the same as that of the optical disk to be corrected, and usually about 50 to 200 mm. However, the diameter may be larger than the optical disk depending on the application.

The thickness of the rigid base 2 may be such that the rigidity as described above can be ensured, and varies depending on the material and the diameter of the rigid base 2, but is usually preferably 1 mm or more.
Although there is no particular upper limit for the thickness, the rigid base material 2 is preferably lightweight for the above-described reason.
It is preferable to set the following.

 The surface of the rigid substrate 2 may be almost flat.

That is, there is no need to have large irregularities or undulations that affect the surface properties of the sheet-like elastic body 3, and it is not particularly necessary that the surface roughness is small.

However, the surface of the rigid base material 2 on the sheet-like elastic body 3 side is
The surface roughness may be adjusted as needed. For example, if the surface roughness is reduced, the adhesiveness with the double-sided adhesive tape 4 can be improved. If the sheet-like elastic body 3 is directly bonded by heat fusion as described later, the surface roughness can be increased. Adhesion can be improved.

The sheet-like elastic body 3 is made of a material having elasticity, and is in close contact with the optical disk by the above-described action.

The material used for the sheet-like elastic body 3 is not particularly limited as long as it can be in close contact with the optical disk. In the present invention, rubber is used.

The rubber used is not particularly limited, and may be appropriately selected from silicone rubber, styrene butadiene rubber, isoprene rubber, chloroprene rubber, nitrile rubber, fluorine rubber, urethane rubber, acrylic rubber, natural rubber, and the like as needed. That is, if it is selected according to various requirements, such as that the dirt of the sheet-like elastic body 3 does not easily adhere to the surface of the optical disk, that the adhesive property with the adhesive tape 4 is high, and that the heat-fusion with the rigid base material 2 is easy. For example, in order to prevent contamination of the optical disk surface, it is preferable to use silicone rubber.

The rubber used for the sheet-like elastic body 3 is ASTM D
Durometer as defined in 2240
In the rubber indentation test according to r), the durometer reading is a hardness in the range of 10-100. When the durometer instruction is less than the above range, it is difficult to improve the surface properties of the optical disc, and the correction of the warp becomes insufficient.When the above range is exceeded, it is difficult to smoothly remove air when the disc is brought into close contact with the optical disc. As a result, the adhesion between the sheet-like elastic body and the optical disk becomes insufficient.

Further, in order to improve the adhesion to the optical disk, the center line average roughness Ra of the surface of the sheet-like elastic body on the side in contact with the optical disk is set to less than 50 μm. As the lower limit of Ra, if the surface is too smooth, it is difficult to separate the sheet-like elastic body from the optical disk, so it is set to 1 μm or more. In addition,
Ra is specified in JIS B0601.

If necessary, the surface of the sheet-like elastic body may be polished so that the surface of the sheet-like elastic body has the above Ra.

The thickness of the sheet-like elastic body 3 may be appropriately determined according to various conditions such as the material and hardness thereof, and is usually preferably about 0.1 to 5 mm. If the thickness is less than the above range, the effect of correcting the warp tends to be insufficient. If the thickness exceeds the above range, the weight tends to increase and the load on the drive device tends to be excessive, and it may not be possible to load the drive device in a state where it is integrated with the optical disk.

The shape of the sheet-like elastic body 3 is preferably a disk shape as in the case of the rigid base material 2, and the diameter thereof may be substantially equal to that of the rigid base material 2.

The sheet-like elastic body 3 does not need to be made of one kind of rubber. For example, the sheet-like elastic body 3 has a structure in which two or more layers of different kinds of rubber are laminated, and is required to have the characteristics required for the optical disk side surface and the rigid base material 2 side. It is also preferable to adopt a configuration that satisfies both the following characteristics.

The rigid base material 2 and the sheet-like elastic body 3 may be directly bonded with various adhesives other than the double-sided adhesive tape shown in the figure. It is also preferable that the sheet-like elastic body 3 is heat-sealed to the rigid base material 2, and in this case, a high adhesive strength is obtained.

The optical disk warp correcting member 1 is usually used as follows.

First, the correction member 1 is placed on the surface of the optical disk, that is, the surface opposite to the light incident surface from the elastic body 3 side, and pressure is applied. The pressure at this time may be appropriately determined within a range in which the two can sufficiently adhere to each other and the optical disc is not damaged, but is usually about 0.01 to 5 kgf / cm ² .

Next, when the application of the pressure is stopped, the elastic body 3 and the optical disk come into close contact with each other, and the optical disk is in a state in which the warp is corrected.

In this state, the optical disk is loaded into the drive device, and various measurements or normal recording and reproduction are performed.

When the optical disk to be corrected is a single-plate optical disk before bonding the substrate or the protection substrate, the sheet-like elastic body 3 is provided with the constituent layers other than the substrate or the protection substrate.
It is preferable to make it adhere to.

For example, in a normal magneto-optical recording disk in which recording light or reproduction light is irradiated through a substrate, a protective layer such as glass, an intermediate layer for improving C / N, and a rare earth metal-transition metal are formed on the substrate surface. Although a recording layer, a protective layer such as glass, and a protective coat made of resin are provided, it is preferable to apply the optical disk warp correcting member in a state where all of these constituent layers are formed.

The reason for this is that, in a magneto-optical recording disk, information is recorded by heating a recording layer with recording light, but when a warp correcting member for an optical disk is applied without a protective layer or a protective coat provided on the recording layer. This is because the heat transfer from the recording layer is significantly different from the actual use state, and accurate measurement becomes difficult.

The optical disk warp correcting member of the present invention is used in such a manner that the sheet-like elastic body is in close contact with the surface of the optical disk opposite to the surface on which recording light or reproduction light is incident. That is, when the present invention is applied to an optical disk on which recording light or reproduction light enters through a substrate, the sheet-like elastic body is used so as to be in close contact with the surface of the optical disk on the information carrying portion side.

In the present invention, the information carrying unit of the optical disc is
In the case of an optical recording disk such as a magneto-optical recording disk, it means a recording layer, and in the case of a read-only optical disk such as a compact disk, it means a substrate surface on which pits and the like are formed.

<Example> Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention.

[Production of Warp Correction Member for Optical Disk] Warp Correction Member 1 for Optical Disk as shown in FIG.
Was prepared.

As the rigid base material 2, a disk-shaped glass plate having an outer diameter of 130 mm, an inner diameter of 15 mm, and a thickness of 1.2 mm was used.

The sheet-shaped elastic body 3 has an outer diameter of 130 mm, an inner diameter of 15 mm, and a thickness of 1
mm disk-shaped silicone rubber was used.

The silicone rubber had a durometer reading of 50 in a durometer indentation hardness test specified in ASTM D 2240. In this measurement, a sheet-shaped silicone rubber having a thickness of 10 mm was used.

The center line average roughness Ra of the sheet-like elastic body surface is 7
μm.

The rigid base material 2 and the sheet-like elastic body 3 were bonded with a double-sided adhesive tape 4.

[Preparation of single-plate optical recording disk] A glass protective layer, an intermediate layer of SiNx, Tb
A recording layer of FeCo, a protective layer of siNx, and a protective coat made of resin were sequentially formed to produce a single-plate optical recording disk.

The resin substrate uses polycarbonate as the material and has an outer diameter of
The disk shape was 130 mm, inner diameter 15 mm, and thickness 1.2 mm.

The sputtering method was used for forming the protective layer, the intermediate layer and the recording layer.

The protective coat was formed to a thickness of 10 μm by applying an ultraviolet-curable resin and then irradiating ultraviolet rays to crosslink and cure.

[Measurement of Warpage Angle] The warpage of the single-plate optical recording disk was measured by a mechanical accuracy measuring device. Specifically, a radius of 30 to 60 mm from the center of the disc
, The displacement of the disk surface was measured at intervals of 5 mm in the disk radial direction and at intervals of 5 ° in the disk circumferential direction, and the maximum value of the warpage angle was calculated.

As a result, the single-plate optical recording disk had a warp in which the surface on the recording layer side was convex, and the maximum warp angle was 10 mrad.

The single-plate optical recording disk is placed on a flat surface with the recording layer side surface facing up, and a warp correcting member for the optical disk is placed thereon, and the single-plate optical recording disk surface and the sheet-like elastic body surface are placed. And contacted. Next, 0.1 kgf from the rigid substrate side
After applying a pressure of / cm ² to bring the single-plate optical recording disk and the sheet-like elastic body into close contact with each other, the pressure application was stopped.

When the maximum warpage angle of the single-plate optical recording disk in close contact with the warp correcting member was measured in the same manner as described above, the maximum warpage angle was 2 mrad.

Further, for comparison, this single-plate optical recording disk was bonded to another single-plate optical recording disk so that the recording layer was encapsulated to produce a product optical recording disk, and the warpage angle was measured for this as well. However, the maximum warpage was mrad.

From these results, the effect of the present invention is clear. That is, by applying the optical disk warp correcting member of the present invention to a single-plate optical recording disk, the amount of warpage is reduced to the same extent as the product optical recording disk after the substrates are bonded.

When the above-mentioned optical disk warp correcting member was applied to a compact disk, it was confirmed that the warp was corrected in the same manner as a single-plate optical recording disk.

<Effect of the Invention> By using the optical disk warp correcting member of the present invention, it is possible to correct the warp of the optical disk and to perform recording and reproduction with the warp corrected.

For this reason, for example, when mass-producing an optical disk in which two substrates are bonded together or an optical disk in which a substrate and a protection substrate are bonded together, when performing various inspections and measurements in a single-plate state in the middle of production, the present invention The use of the optical disk warp correction member enables quick and accurate inspection and measurement.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a preferred embodiment of a warp correcting member for an optical disk according to the present invention. DESCRIPTION OF SYMBOLS 1... Warp correcting member for optical disc 2... Rigid base material 3... Sheet-like elastic body 4.

Claims (3)

(57) [Claims] 1. A member for correcting a warp of a single-plate optical disk having an information carrying portion on a substrate, comprising a sheet-like elastic body on a rigid substrate, wherein the sheet-like elastic body is made of rubber. This rubber is composed of
In a rubber indentation hardness test using a durometer specified in ASTM D 2240, the
And a center line average roughness Ra of 1 μm on the surface of the sheet-like elastic body.
As described above, a warp correcting member for an optical disk, which is less than 50 μm, and is configured to correct the warp of the optical disk by bringing the surface of the sheet-like elastic body into close contact with the optical disk surface. 2. A warp correcting member for an optical disk according to claim 1, wherein said rigid substrate is made of glass, metal or ceramic. 3. An optical disk having a configuration in which a pair of substrates each having an information carrying portion is bonded to each other or an optical disk having a configuration in which a substrate having an information carrying portion and a protection substrate are bonded to each other before the substrate or the protection substrate is bonded. A method for inspecting in a single-plate state, wherein the sheet-like elastic body surface of the optical disk warp correcting member according to claim 1 or 2 is brought into close contact with a single-plate optical disk surface to correct the warp. An inspection method for an optical disk, comprising: