DE19748699A1 - Process for gluing data carrier disks - Google Patents

Abstract

In order to glue DVD halves together, a circular adhesive track (2) is deposited on one DVD half (1). The other DVD half (1) is then bent along an axis which is parallel relative to the data carrier half, and afterwards, is placed onto the first data carrier half such that punctiform contact surfaces result. By lifting the first data carrier half, the bent data carrier half (5) is pressed in a straight manner such that a ring-shaped contact surface results. Said ring-shaped contact surface is controlled afterwards and enlarged by means of capillary and centrifugal forces. A touchpad with specially configured grippers serves to hold and stack the bent data carrier half.

Description

The invention relates to a method for gluing data carrier disks, at which is applied to a disk half of adhesive and the Disk halves are moved towards each other, and a tool for Execution of the procedure.

In particular, the invention relates to a method for producing a DVD. This is a polycarbonate lens made from two of the outer ones Dimensions equal halves. The shape of the DVD as well as the shape of the individual halves correspond to the well-known compact disk. Two 0.6 mm thick disk halves become one in the described method 1.2 mm thick DVD put together.

To connect the halves of a DVD together, one Disk half coated with adhesive or it becomes an adhesive figure, such as for example, an annular trace of adhesive. After that, this Half in a precisely defined way with the other half put together. The entire gluing process is carried out under clean room conditions and carried out free of static charges.

When applying the adhesive and especially when joining the Air halves should be avoided and it was therefore in the EP 443 797 proposed to coat two data carrier halves with adhesive  and first to spherically bend one half of the data carrier and then with the to bring others in touch. The contact surface thus moves as an annular surface from the center outwards. With this method, however, initially arise Difficulty in spherically bending the plate and especially in Air pockets cannot be avoided when the panels are joined together.

The invention is therefore based on the object of a generic method to develop so that when gluing the disk halves Air pockets between the disk halves can be avoided. Furthermore becomes a tool for performing the method according to the invention suggested.

In terms of the method, the task is solved in that before touching the Disk halves a disk half by a parallel to the disk half Axis is bent.

Bending around an axis parallel to the disk half is very easy to carry out because the disk halves used in practice are very flexible are. If now such a curved half of the volume with another Half of the data carrier comes into contact, depending on the adhesive application a maximum of one line of contact, which is when relaxing the curved Disk half widened until the disk halves lie flat on top of each other.

The bending of the elastic half of the data carrier allows one in time and place precisely defined touch sequence and thus a connection between the two Disk halves with complete exclusion of air bubbles.  

While in the case of flat data carrier halves coated with adhesive, the Contact can be made on one line by bending two Disk halves and feeding one another at an angle Disk halves can be achieved a point contact, when relaxing the elastic disk halves merges into a contact surface.

However, an initial selective contact can also be achieved by that the adhesive is applied as a trace of adhesive. The curved one Half of the disk then only touches the unbent disk half selectively and then on curved lines. Preferably the Adhesive trace applied to the unbent disk half, because of the Mechanism for bending the other half of the disk also as Feeder can be used.

A preferred method variant provides that a flat data carrier half is moved towards the curved half of the data carrier. This allows an easy one constructive structure. A particularly advantageous, relative movement between the disk halves are created by the curved disk half is kept elastic and straight from the unbent disk half is bent. This allows a uniform with little technical effort Spread the adhesive surface.

To avoid the formation of bubbles, it is also proposed that the Disk halves when a disk half touches the Adhesive of the other half of the disk moves relatively slowly towards one another become. Since this point of contact tends to form bubbles, a  Slowing down of the process at this point, the escape of air facilitated.

Another critical moment is the transition from arc-shaped Touch surfaces to a closed touch surface and therefore it becomes suggested the disk halves relatively slowly even at this moment move towards each other to avoid air pockets.

As well as the two data carrier halves in connection via an adhesive track stand, they are advantageously held for a period of time to spread of the adhesive ring by capillary forces. This period of time will preferably matched so that the adhesive ring is up to one so-called stacked bead of the disk has run.

In the meantime, but especially afterwards, they will have a Adhesive track related disk halves a period of time rotated an axis perpendicular to the disk halves. This overlaps the capillary force is a centrifugal force in the outer edge area of the Adhesive area increases the flow rate and on the inner edge area of the Adhesive area slows or stops the flow rate.

The tool for performing the method according to the invention has Gripper for gripping at least one data medium half and stands out characterized in that the grippers for bending the disk half by one Disk half parallel axis are movably arranged. The invention, preferably on the outer edge of the disk half  attacking grippers, are therefore not on a circular line, but themselves arranged opposite each other, so that with these grippers the disk half can be bent according to the inventive method. Here it is not necessary that the bend of the disk half exactly one arc corresponds. Understandably, any convex bend is possible whose curve is preferably based on a precalculated touch sequence the disk halves is matched.

Because the position of the gripper changes when the gripper is lifted proposed that the grippers are arranged elastically. This enables the Bending the disk half an inclination of the grippers relative to one Vertical on the disk half.

In order to move the data carrier disk faster during transport lower disk plate half relative to the upper disk half avoid, it is suggested that the tool be a protruding element has that in an opening in the disk or in a disk half can be introduced. This above element occurs in fast, horizontal Movements in contact with the disk and affects the inertia of the Disk.

It is advantageous if the projecting element has a depression which for centering cooperates with an opposing elevation. This facilitates exact centering between opposing ones Disk halves.  

Bending one half of the data carrier without damage is facilitated by that the tool has a support opposite the grippers with a a half of the disk has an angled surface.

An embodiment of the method according to the invention and a Tool according to the invention are shown in the drawings and are in following described in more detail. It shows

Fig. 1 is a plan view of a DVD-half,

Fig. 2 is a plan view and a section through two superimposed DVD halves,

Fig. 3, the contact points of the first contact of the DVD-halves,

Fig. 4, the extent of the contact points while relaxing the bent DVD-half,

Fig. 5 shows the formation of a circular contact surface,

Fig. 6 shows the enlargement of the contact surface by capillary forces,

Fig. 7 shows the enlargement of the contact surface through centrifugal forces,

Fig. 8 is a view of a tool according to the invention,

Fig. 9 is an exploded view of a part of the tool according to the invention,

Fig. 10 shows the positioning of the tool,

Fig. 11, the bending of the DVD-half of the tool,

Fig. 12 holding the DVD-half of the tool,

Fig. 13 is a bearing surface of the tool and

FIG. 14 shows an enlarged section through the contact surface according to FIG. 13 according to lines XIV-XIV.

The process according to the invention and the process according to the invention are described below Tool explained using the example of a DVD disk. There are two to connect circular disc-shaped polycarbonate discs. This Process is under clean room conditions (class 100) and free of static Charges carried out.

First, a circular adhesive track is placed on one half of the disk applied. As an alternative to the circular shape, the adhesive track can also be one by one Radial serpentine line, an oval or centered on the DVD half also be a broken curve. The height and width of the adhesive track vary depending on the desired cycle time and the specific properties of the Adhesive. Many properties of the adhesive can be achieved by tempering the  Adhesive can be varied.

The method is described below with the aid of a circular adhesive track 2 applied to the data carrier half 1 . This adhesive track 2 is concentric with the center hole 3 outside the stacking bead 4 of the DVD.

The adhesive track has the same cross-section at every point. The adhesive is tempered to room temperature and has a viscosity of approx. 100 mPa. The applied trace of adhesive has no air pockets. The radius of the Adhesive circle is based on the viscosity and flow behavior of the adhesive and the desired cycle time. In the present case it is 28 mm ,. the width of the track is 8 mm and the height of the track is 2 mm.

After the adhesive has been applied to the lower half of the DVD the halves joined. To do this, the second half of the DVD is inserted before Tool, the so-called touchpad, slightly curved.

Fig. 2 shows the two DVD halves 1 and 5 shortly before joining. In order to glue the two halves 1 , 5 together, the lower half 1 , on which the adhesive track 2 is applied, together with a base, not shown, is raised with an experimentally determined speed profile. The lower unit can be moved to the upper plate with an accuracy of 0.5 µm. During this movement only the removal of halves 1 and 5 is reduced.

When moving the disk halves 1 and 5 towards each other, a crucial point in the gluing process is the moment of contact between the upper, curved half and the adhesive track. The curvature of the upper half of the data carrier 5 results in only two contact points 6 , 7 . This contact torque is approached at a very slow speed, such as 3.7 × 10 ^-4 m / sec, so that the low speed and small contact area in points 6 and 7 result in a bubble-free contact. This selective contact has the additional advantage that even manufacturing tolerances in the curvature of the DVD halves do not lead to air trapping.

The lower data carrier half 1 is then raised further, so that the contact points enlarge into two semicircles, as shown in FIG. 4. This process can be carried out at a higher speed, such as 7.4 × 10 ^-3 m / sec. The formation of air pockets is less critical in this phase because the adhesive has a pronounced flow front during the formation of the semicircles, which easily displaces the air.

Since the lower data carrier half 1 lies on a flat, firm surface and the upper data carrier half is held elastically by the touchpad, the upper data carrier half 5 is deliberately bent straight in a symmetrical manner.

Another critical moment is the point in time at which the two contact points 6 and 7 , which have now been formed into semicircles 8 and 9 , at points 11 and 12 form a circle. In this phase, the speed of the lower data carrier half 1 is reduced to approximately 3.7 × 10 ^-4 m / sec, so that the flow fronts can run into one another without bubbles. Until the flow fronts converge, the upper data carrier half 5 is held by the touchpad, so that it still has a very slight bend. As soon as the contact surface has closed into a circle, the upper data carrier half 5 is detached from the touchpad, so that the two DVD halves lie parallel on one another.

The distance between the DVD halves 1 , 5 lying on top of each other is in the micrometer range, so that the adhesive ring expands in the radial direction as a result of the capillary force.

The further expansion of the adhesive ring 12 takes place from the inner edge 13 of the adhesive ring 12 to the inside and from the outer edge 14 to the outside by capillary forces. This process can be controlled by rotating the data carrier disk 1 according to the arrows 15 , 16 in FIG. 7 and the centrifugal force generated thereby.

In the exemplary embodiment, the distribution of the adhesive is divided into two steps. The first step is to wait until the inner edge 13 of the adhesive ring 12 has expanded to the stacking bead (r inside = 18 mm) as a result of the capillary force.

As soon as the inner edge 13 of the adhesive ring 12 has reached the stacking bead, the data carrier plate is rotated in, for example, 2200 revolutions / min. transferred. The axis of rotation is perpendicular to the disk surface and runs through its center. The centrifugal force acting on the adhesive during rotation prevents the adhesive from spreading beyond the stacking bead 17 and at the same time supports the flow of the adhesive to the outside. The rotational speed profile is determined experimentally so that the adhesive ring on the inside spreads exactly to the stacking bead and remains there, while it flows on the outside without bubbles to the edge. Any excess adhesive is thrown off by the rotational movement over the outer edge 18 of the data carrier plate.

The adhesive is cured in a subsequent process of DVD production.

The tool 20 shown in FIG. 8 is also called a touchpad and is necessary for the gluing process and for the transportation of the DVD half and the DVD produced during the process.

The upper region 21 of the touchpad 20 serves for fastening and aligning the touchpad, the middle region 22 serves as a vacuum supply with its control and the lower region 23 serves as a fastening device for a DVD or a half of a DVD. The individual components of the middle and lower regions 22 and 23 are shown in more detail in FIG. 9. A plurality of channels 25 , 26 are provided in a block 24 in order to supply vacuum to suction cups 27 , 28 , 29 which are screwed into these channels. A piston 30 is centrally attached to this block 24 and cooperates with a vertically movable cylinder 32 via piston guide bands 31 . By means of the spring 33 , the cylinder 32 is pressed outwards into a 0 position. Further vacuum suction devices 34 , 35 , 36 are attached to the piston and, depending on the spring position of the spring 33, look more or less far out of an opening 37 in the cylinder 32 . The cylinder 32 is ultimately screwed to the block 24 vertically movable with the screws 38 and washers 39 by a defined amount.

When using the touchpad 20 , the DVD half 5 initially lies on angled surfaces 40 , 41 of a support 42 . To record the half of the DVD, the touchpad is first moved to the position shown in FIG. 10, so that the suction heads 36 , 37 can grip the DVD. In this position, the DVD half can be easily gripped and conveyed.

To carry out the method according to the invention, the touchpad 20 is lowered beyond the position described above until the vacuum suction heads 29 , 43 touch the outer edge of the DVD half 5 . A chuck 45 attached centrally to the system presses the cylinder 32 upward against the force of the spring 33 , as a result of which the suction heads 36 , 37 emerge more strongly from the cylinder 32 . Since the suction heads 36 , 37 press the middle part of the DVD into a cavity 44 between the surfaces 40 , 41 , the DVD half bends.

As soon as negative pressure is also applied to the outer vacuum suction heads 29 , 43 , the touchpad 20 together with the data carrier half 5 can be raised. When lifting the counterforce on the cylinder 32 decreases, so that a gripper chuck 49 attached to the cylinder penetrates into the center hole 3 of the disk half. Like the inner vacuum suction heads 36 , 37, which consist of a plastic material, the outer vacuum suction heads 29 , 43 are likewise elastic in the vertical direction. This is important because the distance between the holding position between the outer and inner vacuum cups increases approximately (1 / cosα-1) times its amount. The vertical elasticity prevents warping of the upper DVD half 5 due to internal tensions.

Figs. 13 and 14, the support show 42 with its angled surfaces 40, 41 and a central support surface Chuck 45, which is by means of a screw 46 and a shim 47 centrally between the angled surfaces 40, screwed 41 into the curved base 48 of the support 42 .

While the data carrier half 5 rests on the angled surfaces 40 , 41 , the data carrier half 5 is centered by the chuck 45 (cf. FIG. 10). Also, when placing the touch pad with its inner and outer suction cups 36, 37, 29, 43 on the surface of the data carrier half 5, the data carrier half is positioned by the chuck 45 5 so that a slipping of the disk half 5 is prevented when placing the touchpad 20 (cf. Fig. 11). Only when the data carrier half 5 is firmly gripped, the touchpaid 20 with the above gripper chuck 49 moves upward, so that the gripper chuck 49 no longer experiences any counterforce through the contact chuck 45 and penetrates into the opening 3 of the data carrier half 5 . As a result, the gripped data carrier half 5 can also be moved horizontally very quickly without a change in position of the data carrier half 5 relative to the touchpad 20 due to inertial forces.

Claims (14)

1. A method for gluing disk disks, in which adhesive ( 2 ) is applied to a disk half ( 1 ) and the disk halves ( 1 , 5 ) are moved towards one another, characterized in that a disk half is touched before the disk halves ( 1 , 5 ) are touched ( 5 ) is bent around an axis parallel to the data carrier half ( 5 ). 2. The method according to claim 1, characterized in that the adhesive ( 2 ) is applied as an adhesive trace. 3. The method according to any one of the preceding claims, characterized in that a flat data carrier half ( 1 ) is moved towards the curved data carrier half ( 5 ). 4. The method according to any one of the preceding claims, characterized in that the curved data carrier half ( 5 ) is held elastically and is bent straight from the unbent data carrier half ( 1 ). 5. The method according to any one of the preceding claims, characterized in that the data carrier halves ( 1 , 5 ) are moved relatively slowly towards each other at the moment of contacting one data carrier half ( 5 ) with the adhesive ( 2 ) of the other data carrier half ( 1 ). 6. The method according to any one of the preceding claims, characterized in that the data carrier halves ( 1 , 5 ) are moved relatively slowly towards one another at the moment of transition from arcuate contact surfaces ( 8 , 9 ) to a closed contact surface ( 12 ). 7. The method according to any one of the preceding claims, characterized in that the data carrier halves ( 1 , 5 ) in connection via an adhesive track ( 12 ) are held for a period of time. 8. The method according to any one of the preceding claims, characterized in that the data carrier halves ( 1 , 5 ) connected via an adhesive track ( 12 ) are rotated for a period of time about an axis perpendicular to the data carrier halves ( 1 , 5 ). 9. Tool for performing the method according to one of claims 1 to 8 with grippers for gripping at least one data carrier half ( 5 ), characterized in that the grippers ( 29 , 43 , 36 , 37 ) are movably arranged to a data carrier half ( 5 ) to bend an axis parallel to the data carrier half ( 5 ). 10. Tool according to claim 9, characterized in that the grippers ( 36 , 37 ) are arranged elastically. 11. Tool according to one of claims 9 or 10, characterized in that the tool ( 20 ) has a projecting element ( 49 ) which can be inserted into an opening ( 3 ) in the data carrier or in a data carrier half ( 5 ). 12. Tool according to claim 11, characterized in that the projecting element ( 49 ) is attached to the tool in a spring-loaded manner. 13. Tool according to claim 11 or 12, characterized in that the projecting element ( 49 ) has a recess which cooperates for centering with an opposing increase. 14. Tool according to one of claims 9 to 13, characterized in that the tool ( 20 ) has a gripper ( 29 , 43 ) opposite support ( 42 ) with an angled to a flat data carrier half ( 5 ) surface ( 41 , 42 ) .