JPH02156449A - Production of magneto-optical disk medium - Google Patents

Abstract

PURPOSE:To easily produce the magneto-optical disk medium having high quality by molding guide grooves on both surfaces of a sheet of a substrate and forming recording films on both the surfaces of a sheet of the substrate. CONSTITUTION:A central shaft 30 is fixed to the central position of a lower stamper 27a and the outside diameter of this central shaft is previously set equal to the inside diameter of the substrate 1a and the inside diameter of an upper stamper 28, then if the substrate 1a and the upper stamper 28 are fitted and inserted onto the central shaft 30, the respective central points align eventually. A transparent material is, therefore, used for the one stamper and after a spacer 29 is disposed to the lower stamper 27a, a 2P resin 5c is coated thereon and the substrate 1a is placed thereon at the time of transferring the guide grooves and pits of the magneto-optical disk medium. The spacer 29 is then disposed and the 2P resin 5c is applied, on which the stamper 28 is placed. The three layers consisting of the resin 5c, the substrate 1a and the resin are inserted between the stampers 27a and 28 and are molded. The molding is irradiated with UV rays through the transparent stamper to cure the resins 5c, 5d. The photoset resin is thus obtd.

Description

Detailed Description of the Invention [1 Already Required] Regarding a method for manufacturing a magneto-optical disk medium for a magneto-optical disk device used as a file device in a computer system, the present invention relates to a method for producing a magneto-optical disk medium by forming a recording film on both sides of a substrate. The purpose is to perform the disk bonding work (to eliminate the effects of firmness and to enable the use of opaque substrate materials). At least one of the side stamper and the upper stamper is made of a transparent material, a photocurable resin is applied to the lower stamper, a substrate is placed on top of it, and then the photocurable resin is applied onto the substrate. Then, an upper stamper is placed on top of the stamper, and the two photocurable resin layers and the substrate are sandwiched and molded between the lower stamper and the upper stamper, and then curing light is irradiated to cure the photocurable resin. By curing the photocurable resin, a photocurable resin layer having guide grooves and pits is formed on both sides of the substrate.

[Field of Industrial Application] The present invention relates to a method of manufacturing a magneto-optical disk medium for a magneto-optical disk device used as a file device in a computer system.

[Conventional technology]

FIG. 4 is a perspective view showing the entire structure of the magneto-optical disk medium.

The magneto-optical disk medium includes a magneto-optical disk 17 which is a recording medium, and two hubs 22 and 23 into which the drive shaft of the magneto-optical disk medium is inserted when the magneto-optical disk medium is attached to a magneto-optical disk device. It consists of

The magneto-optical disk 17 is made by bonding two magneto-optical disks together so that both sides of the disk surfaces can be used as recording surfaces, and sandwiching the disks between two hubs 22 and 23.

Next, a conventional manufacturing process for this magneto-optical disk medium will be explained.

FIG. 5 is a process diagram illustrating the manufacturing process of a magneto-optical disk medium. The manufacturing process is roughly divided into three processes, and a magneto-optical disk medium is completed through a substrate process, a film forming process, and an assembly process.

FIG. 6 is a diagram illustrating a substrate process using a 2 P (photo-polymer) transfer method. The substrate process will be explained along the process diagram of FIG.

First, the surface of the tempered glass substrate l is polished in a polishing step 2, and then the tempered glass substrate is cleaned in a cleaning step 3.

Next, between the stamper 4 and the tempered glass substrate l, 2P
(Photo-polymer) Filled with resin 5, molded, and irradiated with ultraviolet rays 15. Since the 2P resin is a resin that hardens when exposed to ultraviolet rays, when the stamper 4 is separated after the 2P resin has hardened, the 2P transfer step 6 is completed and the 2P resin layer 5 is formed on the tempered glass substrate 1. A transfer method substrate 16 is completed. At this time, a spiral guide groove 18a is formed on the transfer substrate 16 by the stamper 4. The thickness of the transfer method substrate 16 is 1.211II
It is about 11.

A recording film is placed on the transfer method substrate 16 manufactured in this way.
The process of forming is a film formation process.

FIG. 7 is a partially cutaway perspective view of the magneto-optical disk 17 on which a recording film has been formed by the film-forming process, and an enlarged view of the end face of the cut portion.

The film forming process consists of a base film sputtering step 7, a recording film sputtering step 8, a protective film sputtering step 9, and a guide groove 18.
A base film 19, a recording film 2o, and a protective film 21 are formed by sputtering in order on the film 2a. At this time,
The thickness of each film is about 0.1 μm, the width W of the guide grooves 18 is about 0.6 μm, and the interval P between the guide grooves 18 is lumμ.
The depth H of the inner groove 18 is approximately 0.05 μm.

The formed magneto-optical disk is completed as a magneto-optical disk medium through an assembly process. FIG. 8 is a perspective view illustrating this assembly process.

The assembly process consists of two magneto-optical disks 17a and 1
7b with adhesive, and put 2 on this magneto-optical disk.
This is completed by gluing the hubs 22 and 23 together.
The magneto-optical disk is initialized in a recording film initialization step 10 and then bonded together. Further, after the assembly is completed, the magneto-optical disk medium is tested in a unit test step 13 before being shipped.

The assembly process will now be described in detail.

FIG. 9 is a diagram illustrating the conventional assembly process. To make the explanation easier to understand, the magneto-optical disk medium is
FIG. 6 is an end view of the cut section taken axially from its center.

Step 2: Set the magneto-optical disk 17a on a stage (not shown) with the recording film facing upward;
Align the rotational center point of the guide groove with the rotational center point of the stage in a.

At this time, the center point of the guide groove of the magneto-optical disk is determined by rotating the stage, tracing the guide groove of the magneto-optical disk using an optical pickup, and measuring the eccentricity of the guide groove.

The subsequent measurement of the center point of the guide groove is performed in the same manner.

Step (2) Apply adhesive 24a to the magneto-optical disk 17a, and attach another magneto-optical disk 17b with the recording film facing downward. The adhesive used at this time is, for example, an epoxy adhesive.

Step (2) Align the center point of the guide groove of the bonded magneto-optical disk 17b with the center point of the guide groove of the magneto-optical disk 17a.

Step (2) UV resin 25a is applied to several places on the outer periphery of the side surfaces of the magneto-optical disks 17a and 17b, and UV light is irradiated to harden the UV resin. At this time, when the UV resin is irradiated with UV light,
Hardens in seconds.

In this process, the UV resin is applied to the magneto-optical disks 17a and 17b.
The reason why it is used on the outer periphery of the side surface of This is for the purpose of In other words, it is a temporary fix.

Step (2) The inner hub 22a is set on a stage not shown, and adhesive 24b is applied to the adhesive surface with the magneto-optical disk. Thereafter, the magneto-optical disk manufactured in step (2) is bonded to the hub 22a.

Step (2) Align the center point of the guide groove of the magneto-optical disk with the center point of the hub 22a.

Step 2: Apply UV resin 25b to several places between the hub 22a and the magneto-optical disk, irradiate UV light to harden the UV resin, and temporarily fix the disk.

Step (2) The outer hub 23a whose adhesive surface with the magneto-optical disk is coated with adhesive 24c is inserted into the outer side of the hub 22a. Next, UV resin 25c is applied to several places between the hubs 22a and 23a, and UV light is irradiated to cure the UV resin and temporarily fasten the hubs 22a and 23a.

Through the above steps, assembly of the magneto-optical disk medium is completed.

[Problems to be Solved by the Invention] Information is read and written to and from a magneto-optical disk medium by rotating the magneto-optical disk medium and tracing the guide groove using optical pink-up.

Therefore, when the magneto-optical disk medium is used in a magneto-optical disk device, it is important that the center of rotation of the guide groove is not eccentric.

Therefore, in each manufacturing process of magneto-optical disk media, work is carried out to prevent eccentricity from occurring at the center of rotation of the guide groove.

FIG. 10 is a cross-sectional view illustrating burrs generated in the 2P transfer step of the substrate process. In the 2P transfer process,
In order to match the center point of the stamper 4 with the center point of the tempered glass substrate 1, the inner diameter D1 of the stamper is made larger than the inner diameter D2 of the tempered glass substrate, and a jig is inserted from the bottom of the stamper so that the center point of the tempered glass substrate is made to match the center point of the stamper.

Therefore, between the tempered glass base Fi1 and the stamper 4, 2
When the 2P resin 5 is filled and molded, if the 2P resin 5 protrudes onto the inner diameter side wall of the stamper 4, burrs 26 are generated. Conversely, if the outer diameter of the stamper 4 is made smaller than the outer diameter of the tempered glass substrate 1, burrs will occur on the outer diameter side walls of the stamper.

Since the burr 26 is generated in a direction perpendicular to the surface of the tempered glass substrate, it causes trouble when the magneto-optical disks are bonded together in the assembly process.

FIG. 11 is a cross-sectional view illustrating the influence of burrs 26 when bonding magneto-optical disks together.

In the assembly process, when the magneto-optical disk 17a and the magneto-optical disk 17b are bonded together with the adhesive 24a, the thickness of the adhesive 24a as a layer is 20 to 30 μm, while the height of the burr 26 reaches im. It is of a certain degree.

Therefore, when the magneto-optical disks are bonded together, the burr 26 causes the following problem.

(a) The burr 26 of the magneto-optical disk 17b hits the magneto-optical disk 17a, making it impossible to set the thickness of the adhesive layer to a predetermined thickness.

(b) The burr 26 is broken and the magneto-optical disks 17a and 17
The recording film of b is damaged.

Furthermore, in the assembly process, the following problem arises because two magneto-optical disks are pasted together.

(c) It is necessary to align the center of rotation three times, which increases the working time.

That is, after determining the rotation center point of the guide groove of the magneto-optical disk 17a in step (2), aligning the rotation center point of the guide groove of the magneto-optical disk 17b with the rotation center point in step (2), and then, in step (2) The magneto-optical disk and hub 22a
In order to match the rotation center of the
A total of 3 times is required.

(d) Between step (2) and step (2), the adhesive 24a needs time to harden, and during this time it is not possible to move on to the next operation.

That is, only after the adhesive 24a is completely cured.
This is because there is a risk that the rotation centers of the guide grooves between the magneto-optical disks may be misaligned, and from the viewpoint of adhesive strength, etc.
This is because the curing time of the adhesive 24a cannot be shortened.

(e) Since they are bonded together with the recording film on the inside, when recording or reading from a magneto-optical disk medium, the recording film is irradiated with laser light through a transparent substrate such as a reinforced glass substrate. Therefore, this transparent substrate,
For example, a tempered glass substrate is required to have uniform and excellent optical properties such as refractive index, transmittance, and birefringence. In addition, high quality surface finishes such as surface roughness, scratches, and bits are required, making them expensive.

(f) Transparent substrates are limited to tempered glass substrates, so if a recording film with a specific composition is formed,
The recording/reading sensitivity for the magneto-optical disk medium is uniquely determined. That is, this is because the optical properties, thermal properties such as thermal conductivity and specific heat, and magnetic properties of the tempered glass substrate cannot be freely selected. Therefore, when various recording/reading sensitivities are required, the material and composition of the recording film are changed, but in that case, good values for optical, thermal, magnetic, and other properties cannot necessarily be obtained. This is not necessarily the case.

The technical problem of the present invention is to eliminate such problems in the manufacturing process of magneto-optical disk media, eliminate the need for bonding work of magneto-optical disks, and reduce the effects of burrs by forming recording films on both sides of the substrate. The objective is to eliminate this problem and also to enable the use of opaque materials for the substrate material, thereby making it possible to freely set the recording/reading sensitivity.

[Means for Solving the Problems] FIG. 1 is a basic principle diagram illustrating a method for manufacturing a magneto-optical disk medium according to the present invention, and is a sectional view taken vertically from the center of a stamper.

When transferring the guide grooves and bits of the magneto-optical disk medium, the lower stamper 27 and the upper stamper 28 are used,
In this case, the size of both stampers is set so that the upper stamper 28 fits into the recess of the lower stamper 27,
A transparent material is used for at least one stamper.

First, a photocurable resin 5a is applied to the lower stamper 27, and the substrate 1a is placed thereon.

Next, a photocurable resin 5b is applied onto the substrate 1a, and an upper stamper 28 is placed thereon.

The photocurable resin 5a, the substrate 1a, and the photocurable resin 5b
The three layers are sandwiched and molded between the lower stamper 27 and the upper stamper 28, and then cured with ultraviolet light or other curing light 15a.
is irradiated through a transparent stamper, and the photocurable resin 5a is
, 5b, on both sides of the substrate 1a,
A photocurable resin layer having guide grooves and bits is formed.

[Function] FIG. 2 is a diagram illustrating the method for manufacturing a magneto-optical disk medium according to the present invention, and is a cross-sectional view taken vertically from the center of the stamper.

The manufacturing method will be explained in order of step numbers.

Process ■ Place the lower stamper 2 on the concave side periphery 27a of the lower stamper 27.
A ring-shaped spacer 29a having the same diameter as the inner diameter of the recess 7
2P resin 5C, which is a photocurable resin, is applied to the stamp surface of the lower stamper 27.

In this case, the spacer 29a regulates the transfer thickness of the 2P resin 5C, and may be inserted and used as necessary, and is not necessarily required. Moreover, several ball-shaped members may be arranged instead of ring-shaped members.

Process■ The substrate 1a is placed in the lower stamper 27.

In this case, by making the inner diameter of the recess of the lower stamper 27 the same as the outer diameter of the substrate 1a, the center point of the lower stamper 27 can be adjusted by fitting the substrate 1a into the recess of the lower stamper 27. The center point of the substrate 1a coincides with the center point of the substrate 1a, and the rotational center point of the guide groove formed and transferred by the lower stamper 27 coincides with the center point of the substrate 1a.

Step ■ On the substrate 1a and around the recessed part of the lower stamper 27,
A spacer 29b is inserted, and 2P resin 5d is applied onto the substrate 1a.

The purpose of the spacer 29b is the same as in step (2) above.

Process■ Insert the upper stamper 28 into the recess of the lower stamper 27,
Apply pressure.

In this case, the outer diameter of the upper stamper 28 is the same as that of the lower stamper 28.
Since the size is the same as the inner diameter of the recess 7, when the upper stamper 28 fits into the lower stamper 27, the center point of the lower stamper 27 and the center point of the upper stamper 28 coincide, and the upper stamper The rotation center points of the guide grooves molded and transferred on both surfaces coincide with each other, and also coincide with the center point of the substrate 1a.

Next, when the 2P resins 5c and 5d are cured by irradiating curing light 15 such as ultraviolet rays from above the upper stamper 28, the 2P resin 5c with guide grooves 18 molded on both sides of the substrate 1a is formed.
, 5d are transferred, and a substrate having guide grooves on both sides of the substrate 1a is completed.

In this case, when the substrate 1a is an opaque member, both the lower stamper 27 and the upper stamper 28 are made of transparent material, and curing light such as ultraviolet rays is applied from both sides of the lower stamper 27 and the upper stamper 28. All you have to do is irradiate it. In addition, when the base Fi1a is a transparent member, one of the lower stamper 27 and the upper stamper 28 is made of a transparent material, and ultraviolet rays are transmitted from the stamper side using the transparent material. What is necessary is to irradiate a curing light such as

With the above steps, the substrate process is completed.

Then, in the film formation process, a base film, recording film, and protective film are formed by sputtering, and in the assembly process, a hub is attached to complete the magneto-optical disk medium, eliminating the need to bond the magneto-optical disks together.

Even if a flash 26a were to occur on the lower stamper 27 side in step (3), the region where the flash occurred would be outside the movement range of the optical head when the magneto-optical disk medium is used in a magneto-optical disk device. A paris with a height of about 1- is tolerable even if left as is.

[Example] FIG. 3 is a sectional view illustrating an example of the manufacturing method of the present invention.

In the case of this embodiment, the basic principle shown in FIG. 1 and the entire (
The same is true. That is, the central axis 30 is aligned with the lower stamper 27.
a, and the outer diameter of the central axis 30 is fixed at the center position of the substrate 1.
By making the inner diameter of a and the inner diameter of the upper stamper 28 equal, the substrate 1a and the upper stamper 28 are
When fitted and inserted into the central shaft 30, their respective center points inevitably coincide.

Therefore, when transferring the guide grooves and pits of the magneto-optical disk medium, at least one stamper is made of a transparent material, and the spacer 29 is first attached to the lower stamper 27a.
After arranging the 2P resin 5C, the substrate 1 is placed on top of it.
Place a.

Next, after placing the spacer 29 on the substrate 1a, the 2P
The resin 5d is applied, and the upper stamper 28 is placed on top of it.

The three layers of the 2P resin 5c, the substrate 1a, and the 2P resin 5d are sandwiched and molded between the lower stamper 27a and the upper stamper 2B, and then ultraviolet rays 15 are irradiated through the transparent stamper to form the 2P resin 5c, By curing 5d, a photocurable resin layer having guide grooves and pits can be formed on both sides of the substrate 1a.

Also, spacers 2 may be provided between the lower stamper 27a and the substrate 1a and between the substrate 1a and the upper stamper 28, if necessary.
9 may be included to regulate the transfer thickness of the 2P resin. In this case, there is an advantage that the spacing and parallelism on both sides of the substrate after 2P transfer are uniform and can be obtained with high reproducibility.

[Effects of the Invention] According to the manufacturing method of the present invention, guide grooves can be formed on both sides of one substrate, so recording films can be formed on both sides of one substrate.

Therefore, there is no need to bond the magneto-optical disks together, and the substrate does not need to be transparent.

Therefore, the following effects can be obtained.

(a) Paris generated in the substrate process no longer poses a problem when using magneto-optical disk media, and
There is no damage to the recording film due to breakage.

(b) In the assembly process, the center of rotation only needs to be aligned once, making assembly extremely easy.

That is, it is sufficient to simply align the centers of the hub and the magneto-optical disk having recording films on both sides. By the way, we used to do this three times.

(c) Adhesion time associated with bonding magneto-optical disks is not required.

(d) Since recording and reading can be performed without passing through a transparent substrate such as a reinforced glass substrate, it is no longer necessary to use a reinforced glass substrate, and the range of substrate material selection is widened. Therefore, inexpensive materials can be selected.

(e) Since recording and reading can be performed without passing through a transparent substrate such as a reinforced glass substrate, the optical characteristics of the recording film are not affected by the substrate. In addition, by selecting the material for the substrate, it becomes possible to freely set the thermal properties and magnetic properties of the substrate, such as thermal conductivity and specific heat, increasing the degree of freedom in designing recording and reading sensitivities.

As described above, according to the method for manufacturing a magneto-optical disk medium according to the present invention, it becomes possible to easily manufacture a high-quality and inexpensive magneto-optical disk medium.

[Brief explanation of the drawing]

FIG. 1 is a sectional view explaining the basic principle of the invention, FIG. 2 is a sectional view explaining the manufacturing method of the invention, FIG. 3 is a sectional view explaining the details of the invention, and FIG. is a perspective view showing the entire structure of the magneto-optical disk medium, FIG. 5 is a process diagram explaining the manufacturing process of the magneto-optical disk medium, and FIG. 6 is a substrate process using the 2P (photo-polymer) transfer method. A cross-sectional view and a perspective view to explain,
FIG. 7 is a partial cutaway view of the magneto-optical disk medium and an enlarged view of the end face of the cut portion, illustrating the structure of the recording film. FIG. 8 is a perspective view illustrating the assembly process. FIG. 10 is a cross-sectional view illustrating the conventional assembly process in the order of steps. FIG. 10 is a cross-sectional view illustrating the formation of paris that occurs in the 2P transfer process. FIG. be. In the figure, 1 is a tempered glass substrate, 2 is a polishing process, 3 is a cleaning process, 4 is a stamper 15, 5c, 5d is 2
P resin, 5a and 5b are photocurable resins, 6 is a 2P transfer process, 7 is a base film sputtering process, 8 is a recording film sputtering process,
9 is a protective film sputtering process, 10 is a recording film initialization process, 1
1 is a veneer adhesion process, 12 is a hub adhesion process, 13 is a unit test process, 14 is a completed magneto-optical disk medium, 15 is an ultraviolet ray, 15a is a curing light, 16 is a transferred substrate, 17 and 17
a and 17b are magneto-optical disks, 18 is a guide groove, 19
20 is a base film, 20 is a recording film, 21 is a protective film, 22.23 is a hub, 24a, 24b, 24c is an adhesive, 25a,
25b, 25c are UV resin, 26 is Paris, 27.27a
is the lower stamper, 28 is the upper stamper, 29.29a,
29b represents a spacer, and 30 represents a central axis. Patent Applicant: Fujitsu Limited Sub-Agent Patent Attorney Yasushi Fukushima 62 Mari's raw broom 1
0 concave 8, Φゐ 7zu death notification Ryokayo Sugegu Ishiriji ＼ Dakishichimi 11
Kuni No. 70 Professional match

Claims (1)

[Claims] Of the lower stamper (27) and the upper stamper (28) for transferring guide grooves and pits of a magneto-optical disk medium,
At least one stamper is made of a transparent material, a photocurable resin (5a) is applied to the lower stamper (27), a substrate (1a) is placed on top of it, and then a photocurable resin is placed on the substrate (1a). The photocurable resin (5b) is coated with the photocurable resin (5b), the upper stamper (28) is placed thereon, and the photocurable resin (5a), the substrate (1a) and the photocurable resin (5b) are coated.
The lower stamper (27) and the upper stamper (28)
), and then irradiated with curing light (15a) to form the photocurable resin (
By curing 5a) and (5b), the substrate (1
A method for manufacturing a magneto-optical disk medium, which comprises forming a photocurable resin layer having guide grooves and pits on both sides of the method of (a).