JPH0714220A - Forming roll of substrate sheet for optical recording medium - Google Patents

Abstract

PURPOSE:To obtain a forming roll of substrate sheets for optical recording media in which a stamper is tightly adhered to base material of the roll and the surface temperature of the stamper is uniformly maintained and which can stably produce formed sheets even when the roll is operated for a long time. CONSTITUTION:A forming roll 2 of substrate sheets for optical recording media is composed of a base material and a long flexible stamper 1 fixed to the peripheral surface of the base material. The stamper is fixed in such a way that the stamper 1 is locally pressed against the surface of the base material at its both side edge sections in the peripheral direction of the roll by means of pressing members 7 provided on holding members 8 at regular intervals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to recording / recording of information by changing optical characteristics such as reflectance with light such as a laser beam.
The present invention relates to a molding roll for continuously manufacturing a substrate of a high-density information recording medium such as an optical disk / optical card for reproduction.

[0002]

2. Description of the Related Art Conventionally, as an optical recording medium, a recording layer is provided on a substrate transparent to light for recording / reproducing information, such as a semiconductor laser, and a protective layer is laminated on the recording layer. On the surface of the substrate for an optical recording medium, usually a groove for tracking, an address information bit, or the like, is provided with a fine preformat of micron order or submicron order. Conventionally, for example, an injection molding method or a compression molding method is known as a method for forming these preformats. However, it is difficult for these methods to satisfy mass productivity and cost.

Therefore, as a method of satisfying these, the present applicant has proposed European Patent Publication 369780 and European Patent Publication 3
No. 69781, a method for producing a substrate sheet for an optical recording medium, in which a resin sheet is melted and extruded to form a resin sheet, and the molded resin sheet is sandwiched between a molding roll and a roll arranged opposite thereto to transfer a preformat. Is disclosed.

In this method, there is provided a roll stamper for molding an information recording medium (hereinafter referred to as a roll stamper) capable of forming a track group of an optical information recording medium in a continuous roll-to-roll process. It is used exclusively.

As a method for producing this roll-shaped stamper, as described in Japanese Patent Application No. 63-264691, a roller-shaped stamper is directly exposed by using a paper-shaped glass mask, and a roller-shaped stamper is produced by direct engraving. It is known how to do it.

However, in the above-mentioned "method by direct engraving", for one roll stamper, a predetermined pattern (tracking groove, information pit, etc., spiral, concentric circles) of a plurality of information recording media is formed. Or a stripe pattern) is formed,
When a defect occurs in a predetermined pattern of one to several information recording media, one roll-shaped stamper is formed by directly engraving the predetermined patterns of a plurality of information recording media by exchanging the entire roll-shaped stamper. The effect of using the predetermined pattern of the information recording medium is extremely poor.

In order to improve the production efficiency, 1
It is necessary to form many predetermined patterns on the roll stamper directly by engraving. Therefore, the roller diameter of the roll stamper becomes large, the weight also increases, and it is a great labor to replace one roll stamper. There was a drawback that it required.

In order to solve such a drawback, a sheet-shaped stamper is produced by an electroforming method, and is fixed with a shape memory alloy via an adhesive between the roller and the roller (Japanese Patent Application No. 63- 285873), or a method in which it is manufactured by a paper lithography technique and fixed by using a heat-shrinkable tube with an adhesive between the roller and the roller (Japanese Patent Application No. 1-38872).

As a method previously proposed by the present applicants, a sheet-shaped flexible stamper is produced by electroforming, fixing tools are attached to both ends of the stamper, and a groove having substantially the same shape as the fixing tool is formed. Is applied at a predetermined position on the surface of the roller that serves as a roll base material, the fixing tool is inserted into the groove to fix the stamper to the roller, and tension is applied to at least one of the fixing tools to fix the stamper to the roller surface. There is a way.

FIG. 10 is a schematic view of the roll stamper 5 described above. In the figure, 1 is a long flexible stamper, 2 is a roller for fixing the long flexible stamper 1, 3 is a stamper fixing tool for fixing the stamper 1 to the roller 2, and 4 is formed on the long flexible stamper 1. Uneven pattern, 6 is a wedge for applying tension to the long flexible stamper 1, 1
Reference numeral 0 is a screw for fixing the stamper to the roller 2. Here, as the long flexible stamper 1, FIG.
As shown in (a) and (b), a plurality of stripe-shaped or spiral-shaped uneven patterns are formed.

According to the above method, the stamper can be mounted in an extremely short time. Further, by preparing a plurality of stampers, when a defect occurs in a specific stamper mounted on the surface of the roll base material, only the relevant stamper needs to be replaced, so that the molding efficiency can be improved.

[0012]

However, the above method also has the following drawbacks.

That is, it is difficult to apply uniform tension over the entire surface of the stamper.

Referring to FIG. 10, the stamper 1 is tensioned by a wedge 6 inserted between the groove and the fixture.

In the above method, the fixing tool on the wedge insertion side is easily deformed, and it is not possible to apply uniform tension over the entire surface of the stamper. As a result, the adhesion between the roll base material surface and the stamper becomes poor, and when a substrate sheet for optical recording media is manufactured using a resin that easily causes birefringence such as polycarbonate, the transferability of the preformat and the low birefringence are The problem that it is not stable occurs.

[0016]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the above problems, and as a result, arrived at the present invention. That is, the present invention is a molding roll for transferring a preformat pattern to a resin sheet obtained by melting and extruding a resin, and molding a substrate sheet for an optical recording medium, wherein the molding roll is a roll base material and a roll base material peripheral surface. The molding roll is composed of a long flexible stamper that is fixed to the roll base. The stamper is a molding roll in which two side edges in the roll circumferential direction are locally pressed and fixed to the roll base surface at equal intervals.

The present invention will be described in more detail below.

FIG. 1 is a schematic view of a roll stamper of the present invention. In the figure, 1 is a stamper, 2 is a roller to which the stamper is fixed on its surface, 7 is a pressing member for pressing and fixing the stamper, and 8 is a holding member for holding the pressing member 7. Referring to FIGS. 1 and 2, the pressing member 7
Has a spherical shape, and 2 in the roll circumferential direction of the stamper 1.
The stampers 1 are fixed to the roller 2 by arranging them at equal intervals at both ends of the side and pressing the equally-spaced parts of the ends of the stamper. The pressing member 7 may be formed in a cylindrical shape as shown in FIG. 3, and the local pressing may be changed from the point pressing state in the case of the spherical shape to the line pressing state. As the pressing and holding member, a bearing commercially available as "bearing with cage" can be used.

The end of the stamper 1 in the inner peripheral direction need not be fixed to the roller 2 as shown in FIG. 1, but if necessary, a slit-like shape having a width similar to the thickness of the stamper 1 is formed on the roller surface as shown in FIG. The groove processing 9 may be performed to fix at least one end of the stamper 1. Further, FIG. 5 shows another example, and as shown in FIG. 5, an end pressing fixture 3 of the stamper 1 adapted to groove processing on the roller may be used. The end fixing portion of the stamper 1 may be only one end and the other end may not be fixed.

Further, it is desirable that the pressing member 7 of FIG. 1 is movable on the surface of the stamper 1 in the roller circumferential direction. That is, when the roller 2 rotates, the pressing member 7 rotates in a direction opposite to the rotating direction, so that the stamper 1 always exerts an adhesion force to the roller 2, which is preferable.

Further, when one end of the stamper 1 is fixed as shown in FIGS. 4 and 5, tension acts on the stamper 1.

[0022]

EXAMPLES The present invention will be specifically described below with reference to examples.

First, as shown in FIG. 6A, a layer of photoresist 13 was formed on a substrate 12 (34 cm in length × 30 cm in width) such as soda lime glass (step A). Photoresist 1
Az1370 (manufactured by Hoechst Japan Co., Ltd.) was used for No. 3, and this was dropped onto the substrate 12 and applied with a spinner to a film thickness of 3000 Å. Then, prebaking was performed at 90 ° C. for 30 minutes.

Next, as shown in FIG. 2B, a laser exposure apparatus [mirror projector mask aligner M
PA-1500 (manufactured by Canon Inc.)] is used to expose a predetermined pattern (striped pattern) of a plurality of information recording media, and developing is performed with a developer Az312MIF (manufactured by Hoechst Japan). A fine groove pattern 13 'such as a tracking groove and an information bit was formed, and a glass master 14 for an optical card was manufactured (step B).

Further, as shown in FIG. 2C, as a pretreatment for forming a metal film by an electroforming method, a conductive treatment is carried out by using a film forming device such as a stapper device or a vapor deposition device (step C). . By forming a nickel film having a film thickness of 1000Å to 2000Å by a sputtering device, a conductive film 15 is formed.
Was formed on the glass master disk 14.

Next, as shown in FIG. 1D, the conductive film 1
The metal film 1 is formed on the glass master disk 14 provided with 5 by electroforming.
6 is formed (step D).

First, the nickel chip in the electroformed layer was set as the + side electrode, and the glass master disk 14 provided with the conductive film 15 was set as the-side electrode. At this time, it is preferable to use the outer peripheral electrode plate 17 as shown in FIGS. 7A and 7B as the electrode plate. This is because the outer electrode plate has a better film thickness distribution than the inner electrode plate. Further, if the outer peripheral electrode plate 17 is formed in a rectangular shape along the shape of the stamper as shown in FIG. 7B, the lines of electric force are concentrated on the edge portion 18 of the electrode plate, and the film thickness distribution may be extremely deteriorated. Therefore, a ring-shaped one as shown in FIG. 7A was used here.

Next, in a nickel sulfamate electroforming solution, the glass master 14 coated with the conductive film 15 is applied to 20 to 3 parts.
While rotating at 0 rpm, the time integral value of the conduction current is 17
~ 34 AH (Ampere Hour) 100 ~ 20
A metal film 16 was formed by depositing nickel metal of 0 μm.

The electroforming solution used here is nickel sulfamate tetrahydrate [Ni (NH ₂ SO ₃ ) ₂ 4H ₂
O] 500g / 1, boric acid [H ₃ BO _3] 35~38g /
1, a bit-preventing agent of 2.5 ml / 1, and the like composition.

Finally, as shown in FIG. 6 (e), the conductive film 15 and the metal film 16 are integrally formed at the same time to the glass master disk 14.
By further peeling, removing the photoresist adhering to the surface, and cutting as shown in FIG. 8, line and space: 9.5 μm / 2.5 μm, step: 25
A stripe-shaped guide groove of 00 Å ~ 3000 Å is formed,
A long flexible stamper as shown in FIG. 5B was obtained (step E).

The flexible stamper is attached to the roller 2
Rolled stampers 5 were obtained by inserting the bearings with a retainer as shown in FIG. 3 which were wound on the surface of No. 1 and heated in advance to 300 ° C. with a tape heater from the respective end faces of the rollers, and then allowed to cool to room temperature. The roll stamper is shown in FIG.
Extruding machine with a diameter of 65 mm (3
The sheet was extruded by a 00 mm width T die) to form a substrate. At this time, the temperature inside the extruder is 270 ° C,
The temperature of the T-die was 320 ° C.

The forming first to third rolls are made of carbon steel having a surface plated with chromium and have a diameter of 100 mm. The second roll is a nickel stamper (thickness: 100 μm) prepared for an optical card. ) Was used by being fixed to a mirror-finished roll as described above. Also, the temperature control of the roll is
This was done by circulating oil in the roll. The temperature of circulation to the first to third rolls is 120, respectively.
At ℃, 120 ℃, 130 ℃, take-off speed 3.0m / m
in, extrusion molding with a substrate thickness of 0.4 mm,
The surface temperature of each roll is 130 ° C for the first roll,
The second roll was 130 ° C and the third roll was 135 ° C.

As a result of continuously molding a 0.4 mm thick polycarbonate resin (Teijin Kasei, Panlite L-1225) substrate sheet under the above-mentioned molding conditions, the preformat pattern for the optical card was faithfully transferred. Furthermore, the stamper on the roll was securely fixed on the roller from the start to the end of molding (after 8 hours) without floating and the birefringence swing range of the obtained substrate sheet was ± 10 mm.
It was kept below.

[0034]

As is apparent from the above description, the roll stamper according to the present invention can exert the following remarkable effects.

Since the tension acting on the stamper is uniform, close contact with the roller surface is achieved. As a result, the temperature of the roller surface, and by extension, the surface of the stamper is kept uniform. Further, since tension is constantly applied to the stamper during molding, the stamper does not loosen and a stable molded sheet can be obtained even when the molding machine is operated for a long time. In particular, when a resin such as polycarbonate that easily causes birefringence is used, the change in the birefringence can be suppressed to be extremely small for a long time, and the transferability of the preformat can be stabilized. .

[Brief description of drawings]

FIG. 1 is a schematic view of a roll stamper of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a schematic view showing another example of the present invention.

FIG. 4 is a schematic diagram of a method of fixing the stamper end portion.

FIG. 5 is a schematic diagram of a method of fixing the stamper end portion.

FIG. 6 is a schematic view showing a manufacturing process of a flexible stamper usable in the present invention.

FIG. 7 is a schematic diagram showing an example of mounting an outer peripheral electrode plate used in a manufacturing process of a long flexible stamper.

FIG. 8 is a schematic view showing a method of cutting a long flexible stamper.

FIG. 9 is a schematic side view showing an example of a manufacturing apparatus used in an embodiment of the present invention.

FIG. 10 is a schematic diagram showing a conventional stamper fixing method.

FIG. 11 is a schematic view of a flexible stamper.

[Explanation of symbols]

 1 Stamper 2 Roller 3 Stamper Fixture 4 Concavo-convex Pattern 5 Roll Stamper 6 Wedge 7 Pressing Member 8 Holding Member 9 Slit-Shaped Groove 10 Fixing Screw 11 Extruder 12 T-Die 13 First Roll 14 Second Roll (Roll Stamper) 15 Third roll 16 take-up machine 17 sheets

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirofumi Uetakahara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (1)

[Claims] 1. A molding roll for molding a substrate sheet for an optical recording medium by transferring a preformat pattern to a resin sheet obtained by melting and extruding a resin, wherein the molding roll is a roll base material and a roll base material periphery. 1. A forming roll, comprising a long flexible stamper fixed to a surface, wherein the stamper is locally pressed and fixed to the roll base surface at equal intervals at two side edges in the roll circumferential direction.