JPH10128221A - Roll coater and production of optical disk using the sane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roll coater capable of always uniformly applying a liq. agent irrespective of a thickness unevenness whom a thin sheet itself has and to provide a producing method of an optical disk using the roll coater. SOLUTION: In the roll coater applying the liq. agent A on the surface of the thin sheet D by providing a transporting stand 1 transporting the thin sheet D to be coater and a coating roll 2 and moving and passing the transporting stand 1 at an under side of the coating roll, the transporting stand 1 is constituted by arranging a holding plate 5 for holding the thin sheet on an upper surface of a base 4 by interposing a gap G. An elastic material 6 is arranged symmetrically with respect to a line to a segment passing in a passing direction of the transporting stand 1 at a center C of the thin sheet D at a surface direction intermediate part of the gap G, and the periphery part of the holding plate 5 is controlled in adjustable the gap G with a gap controlling means 7 and 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll coater for applying a liquid agent such as an adhesive to a thin plate such as an optical disk, and more particularly to a roll coater suitable for applying an adhesive to an optical disk and an optical disk using the roll coater. It relates to a manufacturing method.

[0002]

2. Description of the Related Art An optical disk has a substrate on which an information recording layer capable of optically recording and reproducing is laminated. While rotating this optical disc at a high speed, the information recording layer is irradiated with a laser beam focused to about 1 μm, and the focus is adjusted and the position is detected.
Digital information such as a document or a video can be recorded by reading or writing the recording bit of the order.

If information is recorded and reproduced on both sides by bonding two optical disks having such a structure, double the recording capacity can be obtained as compared with a single-sided single disk. In order to manufacture such a two-layer bonded optical disk, a step of applying an adhesive to each disk is required. However, in the adhesive application process, if the adhesive application unevenness occurs, the bonded optical disk may be deformed or a partial density variation may occur, causing imbalance when the optical disk is rotated at high speed. However, this may cause a bit error.
Therefore, in order to manufacture a two-layered optical disk, a high-precision adhesive application technique for uniformly applying an adhesive is required.

Conventionally, as an apparatus for applying an adhesive to an optical disk as described above, the optical disk is placed on a carrier and passed under the application roll, and the optical disk is pressed against the surface of the application roll when passing the optical disk. There is an apparatus in which an adhesive of an application roll is applied. JP-A-4-1498
No. 39 discloses that a rubber cushion plate is arranged on the upper surface of a carrier to uniformly apply an adhesive by such a method.
There is disclosed an optical disk in which an optical disk is sucked and held on the rubber cushion plate.

However, in the above-mentioned adhesive application device,
Since the rubber cushion plate is formed on the entire surface of the optical disk so as to face the same shape, the elastic force cannot be controlled. Therefore, when the optical disk is pressed against the application roll as described above, slight vibration occurs. And deformation,
There was a possibility that the coating of the adhesive might be uneven or the optical disk might come off the comb cushion plate.

As described above, in order to eliminate the adverse effects caused by bringing the optical disk on the carrier table into pressure contact with the application roll, a method of preventing the optical disk from being pressed against the application roll can be considered. However, in this method, since the disc substrate has thickness unevenness generated at the time of molding, a gap between the optical disc and the application roll fluctuates, and it is inevitable that a variation occurs in the application layer. For this reason, there is a disadvantage that a troublesome correction operation for correcting the thickness to be constant for each lot is required as a post-process.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a roll coater for applying a liquid material such as an adhesive to a thin plate such as an optical disk, so that the liquid material is always uniformly applied irrespective of the thickness unevenness of the thin plate itself. It is to provide a roll coater which can be used. It is another object of the present invention to provide a method for manufacturing an optical disk having a structure in which an adhesive as a liquid agent is uniformly applied to a predetermined thickness.

[0008]

According to the present invention, there is provided a roll coater comprising: a transfer table for transferring a thin plate to be coated on an upper surface thereof; and a coating roll for forming a liquid material in a thin film on the outer peripheral surface. In a roll coater for applying a liquid material to the surface of a thin plate by pressing the thin plate against the outer peripheral surface of the application roll by moving the transfer table in a direction intersecting the roll axis below the roll, And a holding plate for holding a thin plate is arranged on the upper surface of the base with a gap interposed therebetween, and the elastic body is arranged in the gap in line symmetry with respect to a center line of the thin plate in the moving direction of the carrier. It is a feature.

As described above, as a structure of the transfer table for bringing the thin plate into press contact with the application roll, a gap is interposed between the base and the holding plate for the thin plate, and an elastic material is interposed at an in-plane intermediate portion of the gap. Therefore, when the gripping plate presses the application roll and passes, the reaction force (elastic force) of the elastic material is controlled so as to be tilted within the range of the gap and to reduce the impact at the time of contact and intrusion. Can be prevented from occurring. Moreover, since the elastic material is arranged symmetrically with respect to the line passing through the center of the thin plate in the moving direction of the carrier, the reaction force is uniformly distributed in the roll axis direction of the application roll, and the liquid material is thinned. On the other hand, it can be applied uniformly so as not to cause thickness unevenness.

In the present invention, if the gap regulating means for adjusting the gap by pressing the edge of the gripping plate is provided, the thin plate gripped by the gripping plate can be horizontally adjusted, and the uniform application can be further improved. . Further, it is possible to prevent the thin plate from being wound up by the application roll when the sheet comes into pressure contact with the application roll. Further, in the present invention, as the holding plate, the surface for holding the thin plate is constituted by a suction pad made of a porous material, and a vacuum chamber is provided on the back surface of the suction pad, and the thin plate is sucked by the negative pressure of the vacuum chamber. It is good to make it adsorb to the pad surface.

Further, in order to bring the thin plate gripped on the gripping plate into press contact with the peripheral surface of the coating roll, the surface height of the thin plate on the gripping plate is set to be slightly higher than the outer peripheral lower surface of the coating roll. Good relationship.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a thin plate as an optical disk,
FIG. 2 is a schematic view illustrating a roll coater according to the present invention when a liquid agent is used as an adhesive, and FIGS. 2 and 3 are a longitudinal sectional view and a plan view showing a carriage mounted on the roll coater of FIG. 1. In FIG. 1, a roll coater 100 is
A moving frame 21 that reciprocates in the horizontal direction is provided on the upper surface of the moving frame 21, and the carrier 1 is mounted on the moving frame 21. The carrier 1 has a structure as described in detail below.
An optical disk D is held on the upper surface. An adhesive application roll 2 is provided above the support table 20 at an intermediate position in the horizontal direction. The adhesive discharged from the hopper 3 is coated in a film shape on the outer peripheral surface of the application roll 2.

A screw shaft 22 is horizontally supported by the support table 20 and is driven to rotate forward and backward by a servomotor 23. A nut 24 attached to the lower part of the moving frame 21 is screwed into the screw shaft 22, and the moving frame 21 reciprocates with the carrier 1 by the rotation of the screw shaft 22. Therefore, the carrier 1 on which the optical disc D is placed is
When the optical disk D is moved to the right along with the moving frame 21 as shown by a dotted line in FIG. 1 and pressed against the peripheral surface of the application roll 2, the adhesive is applied to the surface of the optical disk D in a film form.

As shown in FIGS. 2 and 3, the carrier 1
A base 4 having a substantially square shape in a plan view is arranged on the lower side, and a gripping plate 5 having a circular shape in a plan view is arranged on the base 4 via a gap G. A suction pad 14 formed in an annular shape from a porous material is fixed to the upper surface of the holding plate 5, and a vacuum chamber 15 is provided on the back surface of the suction pad 14. Further, the vacuum chamber 15 is connected to a negative pressure source (not shown) via a connection pipe 16. Therefore, the optical disc D placed on the surface of the suction pad 14 is suction-held by the negative pressure of the vacuum chamber 15.

In this embodiment, the optical disc D has a hub dh at the center. The suction pad 14 has a circular hole 14a to fit the hub dh of the optical disc D. In addition, the suction pad 14
The optical disk D is formed to have substantially the same outer diameter as that of the optical disk D, and the attraction force is uniformly distributed over the entire surface of the optical disk D to which the adhesive is applied. Further, an aligning pin 5 is attached at the center of the gripping plate 5 so that the optical disk D is concentrically mounted on the suction pad 14.

On the other hand, the base 1 has a spring 1
A sphere 12 elastically supported by 1 is provided. Since the spherical body 12 is constantly pressed in the direction of the optical disk D via the conical groove 5a provided on the lower surface of the gripping plate, the optical disk D after application by the roll 2 can be restored to the horizontal position before application. A concentric annular groove 13 is provided around the sphere 12, and two left and right arc-shaped elastic members 6 are dispersed in the annular groove 13. The gripping plate 5 is elastically supported on the base 4 via the gap G via the elastically supported sphere 12 and the elastic material 6. As the elastic material 6,
A rubber O-ring, coil spring, or the like can be used.

The two elastic members 6 are fitted into the annular groove 13 so as not to be displaced, and as shown in FIG.
Are arranged symmetrically with respect to a line passing through the center C of the optical disk D with respect to the moving direction of the optical disk D, and more preferably, pass through the center C of the optical disk D in parallel with the axial direction of the coating roll 2 as shown in FIG. The line is also symmetric with respect to the line segment. Further, a cover plate 7 whose center is hollowed out so as to surround the circular holding plate 5 is fixed on the base 4 having a square shape in a plan view. The boundary between the cover plate 7 and the gripping plate 5 is such that the outer peripheral edge of the gripping plate 5 has a stepped upper surface,
The inner peripheral edge portion of the cover plate 7 is formed in a stepped shape on the back surface side, and the two stepped portions overlap each other, so that the stepped portion of the cover plate 7 overhangs the stepped portion of the gripping plate 5.

A plurality of (six in FIG. 3) bolts 8 are screwed into the stepped portion of the cover plate 7 at equal intervals in the circumferential direction, and the lower ends of these bolts 8 are provided on the stepped portion of the gripping plate 5. Abuts against the bottom surface of the recess 9 formed. The cover plate 7 thus configured
The bolt 8 and the bolt 8 constitute a gap regulating means for regulating the gap G between the base 4 and the holding plate 5. That is, when the lower end of the bolt 8 contacts the bottom surface of the concave portion 9 on the side of the holding plate 5, it acts as a stopper, and keeps a certain gap G so that the holding plate 5 does not float upward. The size of the gap G can be adjusted by screwing the bolt 8 up and down.

The gap regulating means adjusts the level of the holding plate 5 elastically supported by the elastic member 6. Therefore, the level of the optical disk D gripped by the gripping plate 5 is adjusted, and the thickness of the adhesive A applied by pressing against the application roll 2 is made uniform. Further, the amount of interference between the surface height of the optical disk D and the lower surface of the outer periphery of the coating roll 2 is adjusted so that the optical disk D is not wound around the outer surface of the coating roll 2.

Using the roll coater 100 described above,
For example, when applying an adhesive to the surface of an optical disk with a hub, it can be performed as follows. Optical disk D
When the hub dh is fitted into the circular hole 14a of the suction pad 14 and fitted to the centering pin 17, the optical disk D
Are concentrically positioned on the suction pad 14, and in that state, are suction-held by the negative pressure of the vacuum chamber 15. The initial displacement amount (gap G) of the elastic member 6 is adjusted to a specific size by the gap regulating means using the cover plate 7 and the bolt 8 in advance, whereby the surface (coated surface) of the optical disk D is adjusted. Are made parallel to the axial direction of the application roll 2.

Next, the transport table 1 is moved so as to pass below the coating roll 2, and the optical disc D is transferred to the coating roll 2.
To make pressure contact. At the moment of this contact, as shown in FIG. 6, the gripping plate 5 is in a state where the contact side of the application roll 2 sinks and tilts with the tip of the bolt 8 of the gap regulating means on the opposite side as a fulcrum. As the contact side of the application roll 2 sinks in this way, the pressing force of the optical disc D at the moment when the contact comes into contact with the application roll 2 is prevented from suddenly changing, so that application unevenness does not occur.

As the carrier 1 moves below the application roll 2, the inclination of the gripping plate 5 changes sequentially, changes horizontally, and then changes to the opposite side from the initial one. However, the elastic member 6 provided on the transfer table 1 of the present roll coater is arranged concentrically with respect to the center C of the optical disc D as shown in FIG. (In the direction perpendicular to) the line segment passing through the center C of the optical disk D, and more preferably the line segment passing through the center C of the optical disk D in parallel with the axial direction of the coating roll 2, so that they are arranged line-symmetrically. The pressing force of the optical disc D against the coating roll 2 is always uniformly distributed per unit length in the axial direction of the coating roll 2 as shown in FIG. 5, so that the adhesive can be uniformly applied without causing coating unevenness. .

When the elastic members 6 are arranged line-symmetrically as described above, and when the diameter of the optical disc D is 3.5 inches,
It is preferable that the radius R in FIG. 4 be in the range of 20 mm to 35 mm, and the angle θ be in the range of 60 ° to 120 °. The thickness of the adhesive A applied to the optical disc D is controlled by controlling the thickness of the adhesive A on the peripheral surface of the application roll 2 or by controlling the relative speed between the rotation speed of the application roll 2 and the moving speed of the carrier 1. Can be adjusted.

The magnitude of the restoring force of the elastic member 6 can be controlled by adjusting the gap G between the base 4 and the holding plate 5 by the gap regulating means. In addition, by fitting the elastic member 6 into the concave groove 13 and preventing its position from changing, uniformity of the restoring force of the elastic member can be maintained. The concave groove 13 performing such a function may be provided on the gripping plate 5 side instead of being provided on the base 4 side as in the illustrated example, or may be provided on both the base 4 and the gripping plate 5. They may be provided in pairs.

The optical disk D to which the adhesive has been applied as described above is transported to a bonding step, and a bonded type optical disk having an information recording layer on both sides can be obtained by bonding two sheets. it can.

[0026]

EXAMPLE An apparatus having the following specifications was manufactured as a roll coater for applying an adhesive to a 3.5-inch optical disk. The gripping plate body of the carrier having the structure shown in FIGS. 2 and 3 is made of aluminum, and as a suction pad, plastic sintering having fine holes having an average diameter of 0.1 mm and a density of about 5100 per cm ² is provided. A body (manufactured by CK Corporation) having an outer diameter of 84 mm (substantially the same as the disk outer diameter) and having a through hole with an inner diameter of 27 mm for fitting a hub was manufactured. This suction pad was precisely machined so that the flatness of the suction surface for the optical disk was 1 μm or less and the parallelism was 5 μm or less.

An O-ring made of silicone rubber having a JIS-A hardness of 45 ± 5 and a diameter of 5 mm was used as an elastic material inserted between the base and the holding plate. This elastic material has an angle θ and a radius R in FIG. 4 where θ = 90 ° R = 27.5 mm
Processed to become. Further, as an annular groove for holding the elastic material, a width of 6 mm, a depth of 4 mm, and a center diameter of 27.5 are formed on the surface of the base.
mm, and the gap G between the gripping plate and the base is set to about 1
mm. As the clearance regulating means, M4 hexagon socket head bolts were used, and six bolts were arranged at equal intervals so that two bolts could be arranged in the transport direction of the transport table. In addition, in order to maintain the position after the gap adjustment, it was fixed with an M4 hexagon nut.

An adhesive was applied to a 3.5-inch optical disk using the above-mentioned carrier, and the relationship between the distance from the center of the optical disk to the load position and the reaction force (restoring force) of the elastic material was measured. However, the measurement result of FIG. 7 was obtained. In order to measure the restoring force, a point load was applied to the surface of the gripping plate (suction pad) with a push-pull gauge, and the load when displaced 0.1 mm downward was read. The value was read as the chord length of the optical disk at the load point. And calculated as the elastic force of the elastic material acting on the holding plate per unit length.

From the results shown in FIG. 7, it can be seen that the pressing force of the optical disc against the application roll is substantially uniform in the axial direction of the application roll.

[0030]

As described above, according to the present invention, a gap is interposed between the base and the thin plate holding plate, and the surface of the gap is formed as a structure of the carrier for pressing the thin plate into contact with the application roll. Since an elastic material is interposed in the inner middle part, when the gripping plate presses the application roll and passes, the reaction force of the elastic material is reduced by tilting within the range of the gap to reduce the shock at the moment of contact. Can be controlled. Moreover, since the elastic material is arranged symmetrically with respect to the line passing through the center of the thin plate in the moving direction of the carrier, the reaction force is uniformly distributed in the roll axis direction of the application roll, and the liquid material is thinned. On the other hand, it can be applied uniformly so as not to cause thickness unevenness. Therefore, even if the thin plate itself has uneven thickness, the liquid agent can always be applied to a uniform thickness regardless of the thickness.

If the edge of the gripping plate is regulated by the gap regulating means, the thin plate gripped by the gripping plate is adjusted horizontally, so that the uniform coating is further improved and the thin plate is pressed against the application roll. Sometimes, it can be prevented from being wound up by the application roll.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a roll coater according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a transfer table mounted on the roll coater shown in FIG. 1 and viewed in the direction of arrows XX in FIG. 3;

FIG. 3 is a plan view of the transfer table.

FIG. 4 is a plan view showing a main part of the same carrier on which an optical disk is mounted.

FIG. 5 is an explanatory diagram showing a state in which the optical disc is in pressure contact with a coating roll.

FIG. 6 is an explanatory diagram showing an initial state in which a transport table has entered a coating roll in the roll coater of the present invention.

FIG. 7 is a graph showing a reaction force on an optical disc when an adhesive is applied by the roll coater of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 carrier 2 coating roll 4 base 5 gripping plate 5 a conical groove 6 elastic material 7 cover plate (gap adjusting member) 8 bolt (gap adjusting member) 11 spring 12 sphere 13 annular groove 14 suction pad 15 vacuum chamber 41 cover 42 hexagon nut D Optical disk (thin plate) A Adhesive (liquid) G Gap C (thin plate) center

Continuation of the front page (72) Inventor Kuju 1-1-1, Sonoyama, Otsu-shi, Shiga Pref.

Claims (7)

[Claims] 1. A transport table for transporting a thin plate to be coated on an upper surface thereof, and an application roll for forming a liquid material in a thin film on an outer peripheral surface, and a lower side of the application roll intersects the roll axis. By moving and passing the carrier in the direction,
In a roll coater for applying a liquid agent to the surface of the thin plate by pressing the thin plate against the outer peripheral surface of the application roll, the transport table is configured such that a holding plate for holding the thin plate is disposed on the upper surface of the base with a gap therebetween. A roll coater in which an elastic body is disposed in the gap so as to be symmetrical with respect to a center line of the thin plate in the moving direction of the carrier. 2. The roll coater according to claim 1, wherein the peripheral edge of the gripping plate is regulated so that the gap can be adjusted by gap regulating means. 3. The roll coater according to claim 1, further comprising elastic support means for pressing a center portion of the grip plate in the direction of the thin plate, wherein the position of the grip plate is regulated by the elastic support means. 4. The roll coater according to claim 1, wherein an upper surface of the holding plate is formed of a suction pad made of a porous material, and a vacuum chamber is arranged on a back surface of the suction pad. 5. The surface height of a thin plate placed on the gripping plate,
The roll coater according to any one of claims 1 to 4, wherein the coater is regulated so as to be located slightly above the outer peripheral lower surface of the application roll. 6. The roll coater according to claim 1, wherein the thin plate is an optical disk, and the liquid is an adhesive. 7. A method for manufacturing an optical disk, comprising applying an adhesive to an optical disk using the roll coater according to claim 1, and then bonding the two optical disks together.