JPH07282474A - Adhesive applying device for adhering optical disk - Google Patents

Abstract

PURPOSE:To improve the flatness of optical disks after sticking by applying an adhesive thereto always at a specified thickness regardless of the thicknesses of the disks. CONSTITUTION:The adhesive for adhering the optical disks of the adhesive applying device for sticking the optical disks to each other is deposited on the surface of a revolving upper roller 23. The optical disks are transported into a spacing part between this upper roller 23 and a lower roller 24 and the adhesive is supplied from the upper roller 23 and is applied on the surfaces of the optical disks. The thicknesses of the optical disks are detected by a disk thickness detecting section 30 and the distance of the spacing between the rollers is controlled by the detected signal, by which the spacing between the surfaces of the optical disks and the upper roller 23 is maintained always constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc such as a video disc, a digital audio disc, a still image, a document file, etc., when a thin optical disc substrate or an optical disc substrate for recording / reproducing needs to be bonded. The present invention relates to an optical disk bonding apparatus and a bonding method.

[0002]

2. Description of the Related Art Generally, an optical disc is promising as an information medium due to its extremely high information density, large S / N ratio and little noise, and is commercialized as a video disc for recording and reproducing digital signals. In recent years, research and development has been carried out as an optical disc.

The most common method of manufacturing this optical disk is to use a disk master called a stamper as a molding die to manufacture a replica of the master by molding such as injection or injection compression, and the signal surface of the substrate thus formed. With a thin film formed on top and a protective film formed on it,
It is completed by pasting.

There are two bonding methods, a hot-melt method using a hot-melt adhesive and an ultraviolet-curing resin method using an ultraviolet-curable resin as the adhesive. Here, a bonding method by a hot melt method using a hot melt adhesive will be described.

An optical disk laminating apparatus and an optical disk laminating method for manufacturing an optical disk will be described below with reference to the drawings.

7 and 8 show a conventional method for manufacturing an optical disc by pasting. Further, FIG. 9 shows a hot-melt adhesive coating device used in a conventional optical disc bonding method, FIG. 10 shows the pressing device thereof, and FIG. 11 shows the results after the optical discs are bonded by the conventional hot-melt method. It is a figure which shows the flatness (warp amount) of an optical disk.

In FIG. 7, 1 is a glass substrate, 2 is a resist film, 3 is a recording laser beam, 4 is a recorded signal portion,
Reference numeral 5 is a conductive thin film, 6 is an electroformed plating film, 7 is an optical disk master called a stamper, 8 is a disk substrate, 9 is a thin film for reflection or recording, 10 is a protective film for protecting the thin film, 11 is an optical disk single plate , 12 are adhesive layers.

7 and 8, FIG. 7A is a resist film forming process, FIG. 7B is an exposure recording process, FIG. 7C is a developing process, and FIG. 8D is a conductive thin film. Forming step, (e) in the figure, electroforming plating step, (f) back surface polishing step and inner and outer peripheral processing step of the optical disc master, (g) in the forming step, (h) in the thin film forming step, The figure (i) shows the protective film forming step, and the figure (j) shows the bonding step.

Further, in FIG. 9, 13 is an adhesive dissolving tank having a heater for melting therein, 14 is an upper roller having a heater, 15 is a lower roller, 16 is a roller rotating motor, and 17 is a feeding movement. A table 18 is a feed motor.

In FIG. 10, 19 is an upper press table and 20
Is a lower press stand, and 21 is a press air cylinder.

To manufacture an optical disk, as shown in FIGS. 7 and 8, first, in a resist film forming step (a), a resist film 2 is formed on a glass substrate 1 by a spin method or the like.
Then, in the exposure recording step (b), a signal is exposed and recorded with the recording laser beam 3 in the exposure recording step (b), and then the signal is developed in the developing step (c) to form the signal portion 4.

Next, in the conductive film forming step (d), 50 to 1 of the conductive thin film 5 of nickel or silver is formed by sputtering or the like.
The nickel plating film 6 is formed to a thickness of 0.2 to 0.4 mm by forming the nickel plating film 6 to a thickness of 00 nm and performing electroforming plating on the electroforming plating step (e).

After removing this from the glass substrate and removing the resist film by washing or the like, the back surface of the optical disk master is set to 0.1 μm or less in the back surface polishing step (f) so that it fits the molding machine mold at the time of molding. The optical disk master 7 called a stamper is completed by polishing to finish the surface roughness and further cutting the inner and outer circumferences according to the mold.

In order to manufacture an optical disk from the optical disk master 7 , the optical disk master 7 is used as a molding die and a resin material such as polycarbonate or acrylic is molded in the molding step (g) to form the master disk 7. The disk substrate 8 to which the transferred signal is transferred is manufactured.

Next, in the thin film forming step (h), a reflective or recording thin film 9 is formed on the signal surface of the disk substrate 8,
The protective film 10 is formed thereon in the protective film forming step (i) to manufacture the optical disk single plate 11.

After that, in the bonding step (j), the pair of optical disk single plates 11 are bonded with an adhesive to complete an optical disk.

Here, in order to bond the optical disk single plates,
First, with a hot melt adhesive coating device as shown in FIG.
A hot melt adhesive is applied on the protective film of the optical disk single plate 11 to a thickness of 100 μm or less.

First, the vertical position of the lower roller 15 is manually adjusted so that the gap between the optical disk single plate and the upper roller 14 becomes a constant distance.

A hot melt adhesive having a melting temperature of 100 to 130 degrees is put in the adhesive melting tank 13 and is heated by an internal heater.
After melting, the roller rotation motor 16 rotates the upper and lower rollers to apply the adhesive to the upper roller 14.

An optical disk single plate (not shown) is placed on the feed moving base 17 with the protective film surface facing upward, and the feed motor 18 moves the feed moving base 17 to move the optical disk single plate to the upper roller 14 and the lower roller. The upper roller 14 applies an adhesive onto the protective film surface of the optical disk single plate by passing through the gap of 15. The thickness of the adhesive applied here is determined by the gap amount between the upper roller 14 and the optical disk single plate.

Next, after applying the adhesive, the first optical disk substrate coated with the adhesive is placed on the lower press table 20 with the adhesive-coated surface facing upward in a bonding press device as shown in FIG. Then, the second optical disk substrate is placed on top of it with the adhesive coated surface facing down, and a pressure of, for example, 3 kg / cm ² or less is applied to the upper press table 19 by the air cylinder 21 for pressing, and the upper press table is On the lower press stand a few tens
It is pressed down for a second and stuck together.

However, since both the upper press table and the lower press table of this pressing device are made flat and the optical disk has a hole having a diameter of about 15 mm to 20 mm at the center, the surface of the pressed optical disk is The pressure distribution becomes weaker in the inner circumference, so that the optical disc after bonding has an outer circumference of 50 μm as compared with the inner circumference as shown in FIG.
It is warped to the top about m.

Further, since the hot-melt adhesive melts at 130 ° C. or higher, the adhesive is burned and deteriorated when used for a long period of time and must be replaced regularly.

This adhesive is replaced by the upper roller 14
Is reversely rotated and the rotation is stopped in a state in which the adhesive is wound around the upper roller 14, the resin is removed with a spatula made of resin, etc., and this operation is repeated until the adhesive in the adhesive dissolving tank is exhausted to replace it. .

[0025]

However, in the above-mentioned structure, the vertical position of the lower roller of the hot melt adhesive coating device must be manually adjusted every time the thickness of the disk is changed. In addition, since the adjustment is performed manually, the distance between the roller and the optical disk single plate changes with each adjustment, and as a result, the adhesive application thickness changes, and the thickness after bonding changes and warpage occurs.
Quality deterioration is likely to occur.

Further, since the bonded optical disks have holes in the inner circumference, the pressure distribution in the inner circumference is weaker than in the outer circumference, and the inner circumference of the bonded optical disks is lowered, resulting in a flatness ( The warp amount) becomes worse from the inner circumference to the outer circumference.

Further, the time for replacing the hot melt adhesive is
Since the degree of change in the color of the adhesive is visually determined, the adhesive cannot be managed sufficiently and the accuracy of the bonded disk is likely to deteriorate.

Further, even in the replacement method, since the upper roller is rotated in the reverse direction and wound around the roller to be removed, the amount which can be removed at a time is small and a considerable amount of time is required for replacement, and the adhesive is high in temperature of 100 degrees or more. Replacement work is also dangerous.

In view of the above-mentioned problems of the prior art, the present invention is capable of automatically applying an adhesive to a constant thickness regardless of the thickness of the optical disc, and attaching the optical disc with very little warpage. A bonding apparatus and a bonding method capable of manufacturing a disk are provided.

Further, the present invention also provides an adhesive replacement method by which the quality of the adhesive can be maintained constant by automating the replacement of the adhesive, and which can be replaced very easily.

[0031]

In order to solve the above-mentioned problems, an optical disk laminating apparatus and a laminating method of the present invention detect the thickness of an optical disk single plate for bonding before applying an adhesive, and detect the thickness. By making it possible to automatically adjust the height of the lower roller in accordance with the above, the gap between the upper roller and the optical disk can always be made constant regardless of the thickness of the disk.

Further, the press table of the pressing device at the time of bonding is made lower in advance in the outer peripheral portion than in the inner peripheral portion, so that bonding with very little warping can be performed. To replace the adhesive, irradiate the melted adhesive with light such as a laser, detect the transmittance (amount of transmitted light), and automatically pump the adhesive in the adhesive dissolving tank when it falls below a certain value. The new adhesive is then discharged.

[0033]

According to the present invention, with the above-mentioned structure, the adhesive can be always applied to a constant thickness regardless of the thickness of the optical disk single plate to be bonded, and the bonding with very little warpage can be performed, so that high quality and high quality can be achieved. It is now possible to manufacture high-precision optical discs stably and easily. In addition, since the adhesive for bonding can always be maintained at a constant quality, bonding with stable quality can always be performed.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical disk laminating apparatus and an optical disk laminating method according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram of an adhesive coating device used for laminating optical disks according to the first embodiment of the present invention.

FIG. 2 is a block diagram showing a disk thickness measuring unit of the adhesive applying device in the first embodiment of the present invention.

FIG. 3 is a block diagram of a pressing device used for laminating optical disks according to the first embodiment of the present invention.

FIG. 4 is a diagram showing the warp amount of the optical disc after the bonding when the bonding is performed by using the bonding method of the first embodiment of the present invention.

FIG. 5 is a block diagram showing an adhesive detecting section for detecting the deterioration of the adhesive of the adhesive applying apparatus in the first embodiment of the present invention.

FIG. 6 is a diagram showing the relationship between the adhesive dissolution time and the transmittance, which shows the deterioration of the adhesive when the adhesive is melted at 150 degrees.

In FIGS. 1, 2, and 5, reference numeral 22 is an adhesive dissolving tank having a heater for melting therein, 23 is an upper roller having a heater for applying an adhesive, and 24 is an adhesive applying roller. A lower roller for sandwiching the disc between the upper rollers.

Reference numeral 25 is a roller rotation motor for rotating the upper and lower rollers, 26 is a roller vertical movement motor for moving the lower roller up and down, and 27 is a roller moving screw for moving the lower roller by the motor.

Reference numeral 28 is a feed moving base for carrying the disc, and 29 is a feed motor for moving the feed moving base.

Reference numeral 30 denotes a disc thickness detecting unit, which detects a disc thickness and moves a lower roller according to the disc thickness as shown in FIG. 2, and a light receiving element 41 and a light receiving element for moving. Feed screw 42 and feed motor 4
3 and a position detector 44 for detecting the positions of the light receiving elements
And A / for converting the detected position signal to digital
The D converter 45, the position setter 46 for setting the correlation between the thickness and the position in advance and comparing the detected position signal with the set value, and the roller vertical movement motor 26 are driven according to the comparison result. A controller 47 for controlling the operation is provided.

Reference numeral 35 denotes an adhesive discharge section, which includes a discharge pipe 31 for discharging the adhesive, an electromagnetic valve 32, a discharge pump 33, and a discharge tank 34.

Reference numeral 36 denotes an adhesive detecting section, which includes a laser 51 for applying light to the adhesive, a transparent glass window 52 for passing light through the adhesive tank, and a light receiving element 53 for detecting transmitted light. A transmissivity converter 54 for converting the detected transmitted light into a transmissivity, a transmissivity setter 55 for setting a replacement time in advance, and a comparator for comparing the detected value with the set value. 56, the adhesive discharge section 35, and the adhesive supply section 37
And a controller 57 for controlling the.

Reference numeral 37 denotes an adhesive agent supply unit including an adhesive agent preliminary tank 38 for supplying a new adhesive agent and an electromagnetic valve 39.

In FIG. 3, reference numeral 48 is an upper press table,
49 is a lower press stand, and 50 is an air cylinder for pressing the upper press stand against the lower press stand.

This optical disk laminating apparatus is shown in FIG.
3 is composed of an adhesive applying device for applying an adhesive as shown in FIG. 3 and a pressing device for bonding as shown in FIG.

In order to bond optical disk single plates with this apparatus, first, an adhesive is applied to the protective film surface of the optical disk single plate with an adhesive applying device.

The application of the adhesive by the adhesive application device shown in FIG. 1 is performed as follows. The hot melt adhesive is put into the adhesive dissolving tank 22 and melted by the internal heater, and the rotation motor 25 rotates the upper roller 23 and the lower roller 24 to apply the melted adhesive to the upper roller 23.

In this state, the optical disk veneer is placed on the moving base 28 for feeding with the protective film facing upward, and the feeding motor 29 feeds the optical disk veneer.

The sent optical disk single plate is irradiated with the laser light of the laser 40 by the disk thickness detecting unit 30 installed above the moving table 29 for sending, and the light reflected by the optical disk single plate is received by the light receiving element 41. Light is received while automatically moving by the feed screw 42 and the feed motor 43, the position with the largest amount of reflected light is detected by the position detector 44, and the signal is A / D
The converter 45 converts it to digital.

Then, the position setter 46 compares this value with a value in which the relationship between the position of the light receiving element 41 and the position of the lower roller 24 is set in advance, and the controller 47 makes the values coincide with each other. By driving the motor 26 for moving the roller up and down, the position of the lower roller is moved up and down by the roller moving screw 27 so that the gap between the optical disk single plate and the upper roller 23 is always constant.

In this state, the optical disk single plate is the upper roller 2
By passing between 3 and the lower roller, the adhesive is always applied to a constant thickness regardless of the thickness of the optical disk single plate.

Next, the optical disk single plates coated with the adhesive to a constant thickness are bonded together by a bonding press device.

As shown in FIG. 3, the upper press table 48 and the lower press table 49 are both adhered on the lower press table 49 of the pressing apparatus in which the outer circumference is lower than the inner circumference by about 50 μm. The first optical disk veneer coated with the agent is placed with the adhesive application side up, and the second optical disk veneer is placed on top of it with the adhesive application side down.
The air press cylinder 50 presses the upper press table 48 against the optical disk single plate at a pressure of 3 kg / cm ² or less for 10 seconds or more.

That is, two optical disk single plates are attached while being pressed while the outer peripheral portion is lowered by about 50 μm.

Thus, the outer circumference of the press table is 5
The warp amount of the optical disk after the bonding when the bonding is performed by lowering it by about 0 μm is very small as 10 μm or less as shown in FIG.

Next, the replacement of the adhesive is performed by the adhesive detecting section 36.
And the adhesive discharge section 35 and the adhesive supply section 37 .

The operation is as follows. As shown in FIG. 5, the light of the laser 51 of the adhesive detecting section 36 is applied to the dissolved adhesive in the adhesive dissolving tank 22 through the transparent glass window 52, and the transmitted light is detected by the light receiving element 53. To do.

The detected signal is converted into the transmittance by comparing it with the original light amount in the transmittance converter 54, and the value of this transmittance and the value preset by the transmittance setter 55 are compared.
Compare with.

When the detected light transmittance falls below the set value, the adhesive controller 57 drives the electromagnetic valve 32 and the discharge pump of the adhesive discharge section 35 to discharge the adhesive to the discharge tank 34 through the discharge pipe 31. At the same time, the adhesive supply unit 3
The electromagnetic valve 7 is also driven to supply a new adhesive to the adhesive dissolving tank.

[0064]

As described above, according to the present invention, the distance between the rollers is automatically adjusted according to the thickness of the optical disk single plates to be bonded, so that the distance is always constant regardless of the thickness of the optical disk single plates. Since the adhesive can be applied to the thickness, the thickness of the optical disk after the bonding can be always constant.

Further, since the pressing table for bonding is preliminarily inclined and pressed obliquely during pressing, the warp of the optical disk after bonding can be extremely reduced.

Further, since the adhesive can be replaced automatically according to the deterioration state of the adhesive, stable bonding can be always performed.

Therefore, a high-quality and high-precision optical disk can be manufactured easily and stably.

[Brief description of drawings]

FIG. 1 is a block diagram of an adhesive coating device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a thickness detection unit of an optical disk single plate according to an embodiment of the present invention.

FIG. 3 is a block diagram of a press device according to an embodiment of the present invention.

FIG. 4 is a diagram showing warpage of an optical disc manufactured in one embodiment of the present invention.

FIG. 5 is a block diagram of an adhesive detection unit of the adhesive application device according to the embodiment of the present invention.

FIG. 6 is a diagram showing changes in light transmittance of a hot melt adhesive.

FIG. 7 is a sectional view showing a general method for manufacturing an optical disc.

FIG. 8 is a block diagram of steps showing a general method for manufacturing an optical disc.

FIG. 9 is a block diagram of a conventional adhesive applying device used for pasting optical disks.

FIG. 10 is a block diagram of a conventional press device used for pasting optical disks together.

FIG. 11 is a diagram showing warpage of an optical disc in a conventional manufacturing method.

[Explanation of symbols]

22 Adhesive Dissolving Tank 23 Upper Roller 24 Lower Roller 25 Roller Rotating Motor 26 Roller Vertical Moving Motor 27 Roller Moving Screw 28 Feeding Moving Base 29 Feeding Motor 30 Disk Thickness Detecting Section 31 Discharging Pipe 32 Electromagnetic Valve 33 Discharging Pump 34 Discharge tank 35 Adhesive discharge part 36 Adhesive detection part 37 Adhesive supply part 38 Adhesive preliminary tank 39 Electromagnetic valve 40 Laser 41 Light receiving element 42 Feed screw 43 Feed motor 44 Position detector 45 A / D converter 46 Position setting Device 47 Controller 48 Upper press table 49 Lower press table 50 Air cylinder 51 Laser 52 Transparent glass window 53 Light receiving element 54 Transmission converter 55 Transmittance setting device 56 Comparator 57 Adhesive controller

Claims (7)

[Claims] 1. An adhesive coating device for bonding an optical disc, which uses hot melt as an adhesive for laminating optical discs, comprising: an adhesive dissolving tank for melting the hot melt adhesive; and applying the adhesive to the disc. Upper and lower rollers for rotating the rollers, a roller rotation motor for rotating the rollers, a disc thickness detection unit for detecting the thickness of the optical disc and controlling the gap amount between the upper and lower rollers according to the thickness, and the disc thickness. A roller up / down moving motor and a roller moving screw for moving the lower roller up and down by a signal detected by the detection unit, a feed moving base for feeding an optical disk, a feed motor for moving the feed moving base, and an adhesive. Adhesive detection section for detecting deterioration of the adhesive, an adhesive discharge section for discharging the adhesive according to the signal detected by the adhesive detection section, and a new adhesive Further comprising an adhesive supply unit optical bonding adhesive applying device according to claim for supplying. 2. A thickness detecting section of an optical disk of a hot melt adhesive applying device, a laser for detecting the thickness, a light receiving element, and a moving means for moving the light receiving element.
A position detector for detecting the moving position of the light receiving element, an A / D converter for converting the signal detected by the position detecting means into a digital signal, and a roller automatically according to the detected thickness. The adhesive application device for optical disk bonding according to claim 1, further comprising a position setter for controlling the position and a controller. 3. An adhesive detecting section for detecting deterioration of an adhesive of a hot melt adhesive applying device receives a light source for irradiating the adhesive and a light emitted by the light source and transmitted through the adhesive. A light receiving element, a transmittance converter that obtains the transmittance of the adhesive based on the detection value of the light receiving element, and automatically bond when the transmittance obtained by the transmittance converter falls below a certain transmittance. The adhesive application device for optical disk adhesion according to claim 1, further comprising a transmittance setting device for replacing the agent, a comparator, and an adhesive controller. 4. The adhesive discharge part of the hot melt adhesive applying device comprises a discharge pipe for discharging the adhesive, an electromagnetic valve, a discharge pump and a discharge tank, and the adhesive supply part comprises:
The adhesive application device for optical disk adhesion according to claim 1, further comprising an adhesive preliminary tank and an electromagnetic valve. 5. An optical disk laminating press device for laminating optical disks with a hot melt adhesive, which comprises an upper press table having an outer peripheral portion lowered by about 50 μm with respect to a central part, and having the same inclination as that of the upper press table. An optical disk laminating press device comprising a lower press table and a pressurizing means for pressing the upper press table against the lower press table. 6. A method of applying an adhesive for bonding optical disks, which comprises bringing an optical disk close to a rotating roller carrying the adhesive on the surface and applying the adhesive on the rotating roller to the surface of the optical disk. At this time, the thickness of the optical disc to be pasted is measured in advance, and the positional relationship between the rotating roller and the optical disc is controlled so that the gap between the surface of the optical disc and the roller becomes constant according to the measured value of the thickness. Characteristic adhesive application method. 7. A method for laminating optical discs by applying pressure to the optical discs by a hot melt method, comprising:
50 μm around the center of the optical disc when pressed
1 at a pressure of 3 kg / cm ² or less with the pressure lowered
A method for laminating optical discs, characterized in that the discs are held together for more than 0 seconds.