JPH08281173A - Adhesive coating device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide an adhesive application device capable of always applying an adhesive with a predetermined application amount, and improving the product yield and production efficiency. Especially. [Composition] A discharge nozzle 15a is connected to a syringe 15 filled with an adhesive, and an air supply pipe 15 is provided.
The discharge pump 30 is connected via b. A first electric heater 32 is provided around the syringe, and a twenty-first electric heater 34 is provided in the middle of the air supply pipe. By controlling the first and second electric heaters by the control unit 23 to adjust the temperature of the compressed gas passing through the syringe and the air supply pipe, the viscosity of the adhesive in the syringe is kept constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive coating device for coating a glass substrate with a sealing adhesive for sealing a liquid crystal in a liquid crystal panel manufacturing process.

[0002]

2. Description of the Related Art In manufacturing a liquid crystal panel, there is a step of bonding a pair of glass substrates having electrodes or alignment films to each other to define a space in which a liquid crystal is sealed.
In this step, first, a thermosetting adhesive for liquid crystal sealing is applied to either one of the pair of glass substrates.

Generally, in this seal adhesive applying step,
First, one of the glass substrates is automatically conveyed onto the stage of the adhesive coating device, and after gauging, the thickness of the glass substrate is measured. Next, the discharge nozzle connected to the syringe filled with the adhesive is moved along a predetermined path on the glass substrate while maintaining a predetermined gap with respect to the glass substrate. At the same time, constant discharge air is supplied from the dispensing unit to the syringe, and the adhesive is applied by being discharged from the discharge nozzle.

Subsequently, beads or the like as spacers are scattered on the area of the glass substrate partitioned by the seal adhesive, and then the other glass substrate is positioned with respect to the glass substrate coated with the adhesive and attached to each other. To match. After that, these glass substrates are heated while applying pressure in the bonding direction to cure the adhesive.

Since the amount of the adhesive applied has a great influence on the performance of the manufactured liquid crystal panel, the width and the amount of the adhesive supplied should be the most appropriate values in the above-mentioned adhesive applying step. It is important to control.

Generally, the adhesive coating width and coating amount are
It is determined by factors such as the diameter of the discharge nozzle, the discharge pressure, the coating speed, the gap between the discharge nozzle and the glass substrate, and the viscosity of the adhesive. Of these, the viscosity of the adhesive is preferably maintained at a constant value during the coating process.

[0007]

However, in the conventional coating apparatus, the viscosity of the adhesive changes with the passage of time, and the amount of the adhesive discharged from the discharge nozzle also changes. Therefore, there is a problem that the coating amount of the adhesive applied to the glass substrate changes with the lapse of time and varies. For example, when an epoxy thermosetting adhesive is used as the adhesive, the temperature of the adhesive decreases with time and the viscosity of the adhesive decreases. As a result, the amount of adhesive discharged from the discharge nozzle gradually increases, so that the coating amount excessively increases and the product yield decreases.

Further, when the viscosity of the adhesive changes as described above, it is necessary to replace the adhesive with an adhesive having an appropriate viscosity, so that the frequency of replacement of the adhesive increases, resulting in waste and production of the adhesive. This leads to a decrease in efficiency.

The present invention has been made in view of the above points,
It is an object of the present invention to provide an adhesive application device which can always apply an adhesive with a predetermined application amount and can improve the yield of products and the production efficiency.

[0010]

In order to achieve the above-mentioned object, an adhesive coating device according to the present invention comprises a syringe filled with an adhesive, a discharge nozzle connected to the syringe, and a compressed gas in the syringe. To adjust the temperature of the compressed gas supplied from the gas supply means and the temperature of the syringe to supply adhesive to the adhesive from the discharge nozzle to adjust the adhesive in the syringe to a predetermined viscosity. And a temperature adjusting means for maintaining the temperature.

The temperature adjusting means includes a first heater provided in an air supply passage extending between the air supply means and the syringe, a second heater provided around the syringe, and a second heater provided around the syringe. A control unit for controlling the first and second heaters,
It has.

[0012]

According to the adhesive coating device configured as described above, the discharge nozzle is moved along a predetermined path while facing the glass substrate of the liquid crystal panel, and at the same time, from the air supply means. When the compressed gas is supplied, the adhesive filled in the syringe is ejected from the ejection nozzle and applied onto the glass substrate along the predetermined path.

During such a coating process, the compressed gas and the syringe supplied from the supply means are kept at a predetermined temperature by the temperature adjusting means. Therefore, the adhesive in the syringe is kept at a predetermined temperature and its viscosity is also kept constant.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 1, the adhesive application device includes a base 10 and a gate-shaped support frame 11 provided on the base 10. A holding table 20 for holding the glass substrate 2 used for manufacturing a liquid crystal panel is provided on the base 10 with its upper surface horizontal. The holding table 20 is positioned and driven in the XY directions by an XY driving device 21 provided on the base 10.

At the center of the support frame 11, a pair of first and second Z-direction driving devices 1 arranged in parallel with each other.
2 and 13 are supported and are located above the holding table 20.

The first Z-direction driving device 12 functions as a discharge nozzle driving means together with the XY driving device 20, and is a first guide rail 12a and along the first guide rail 12a in the Z-direction, that is, along the first guide rail 12a. , Holding table 20
And a first slider 12b slidably provided in a direction orthogonal to the upper surface of the first slider 12b. First slider 1
A ball screw (not shown) provided in the first guide rail 12a is rotatably engaged with 2b.

The ball screw has a first Z-direction driving device 12
It is adapted to be rotationally driven by a first pulse motor 14 attached to the upper end of the. The pitch of the ball screw is 2 mm, and the first pulse motor 12 drives by dividing one pitch of the ball screw into 4000 pulses.

Then, as shown in FIG. 2, a syringe 15 filled with an adhesive is attached to the slider 12b of the first Z-direction driving device 12, and a discharge nozzle 15a is provided at the lower end of the syringe. ing. Also, syringe 1
At the upper end of 5, the discharge pump 3 is connected via the air supply pipe 15b.
0 is connected. The discharge pump 30 includes a control unit 2
The operation is controlled by 3 and functions as an air supply means for supplying compressed gas such as air or nitrogen to the syringe 15.

Further, the adhesive applying device comprises a temperature adjusting mechanism 40 for keeping the temperature of the compressed gas in the syringe 15 and the air supply pipe 15b so as to keep the viscosity of the adhesive filled in the syringe 15 constant. There is. That is, syringe 1
Around the circumference of 5, a first electric heater 32 for keeping the syringe warm is wound. In addition, the air supply pipe 15
A second electric heater 3 for keeping the temperature of the compressed air discharged from the discharge pump 30 and flowing through the air supply pipe is provided on the outer periphery of the middle part of b.
4 are provided. First and second electric heater 3
2, 34 are connected to the control unit 23 via power sources 36a, 36b, respectively, and the temperature control is performed by this control unit.

As the adhesive filled in the syringe 15, an epoxy resin type thermosetting adhesive, for example, one mainly composed of Struct Bond (trade name) (manufactured by Mitsui Toatsu Co., Ltd.) is used. FIG. 3 shows the relationship between the viscosity and the temperature of this epoxy resin thermosetting adhesive. As can be seen from this figure, the epoxy resin thermosetting adhesive starts to cure at about 100 ° C and has a viscosity of about 40,000 to 60,000 cP (centipoise) suitable for application at about 28 to 32 ° C. Have.

Therefore, in the coating step to be described later, the control unit 23 operates the first and second electric heaters 32 and 34 to keep the compressed gas passing through the syringe 15 and the air supply pipe 15b at about 30 ° C. The viscosity of the adhesive filled in the syringe 15 is maintained at about 28 to 32 ° C suitable for application.

On the other hand, as shown in FIG. 1, the second Z-direction driving device 13 is constructed similarly to the first Z-direction driving device 12, and the second pulse motor 16 causes the supporting frame 1 to move.
The second slider 13b is vertically driven along the second guide rail 13a attached to the first slider 13. A detection probe 18 is attached to the second slider 13b via an X-direction positioning device 17.

As shown in the enlarged view of FIG. 4, the detection probe 18 has a first detection lever 18a extending downward with its axis vertical and a direction of the syringe 15 with the axis substantially horizontal (X direction). It has a second detection lever 18b extending to the.

The detection probe 18 generates a probe signal when the first and second detection levers 18a and 18b are displaced by a certain amount in the XYZ directions. This detection probe 18
Is used in an ordinary three-dimensional measuring device, and the accuracy of reproducibility of displacement detected by the first and second detection levers 18a and 18b is 2 to 3 μm (± 1 to ± 1.5 μm). is there.

The first and second Z drive devices 12, 1
3, the detection probe 18, the adhesive supply device (not shown), and the XY drive device 21 are connected to the control unit 23. The control unit 23 has an arithmetic function and drives and controls the first and second Z drive devices 12 and 13, the detection probe 18, the adhesive supply device, and the XY drive device 21 by a predetermined program. .

Next, the operation of applying an adhesive to the glass substrate 2 for a liquid crystal panel using the adhesive applying device configured as described above will be described. First, the holding table 20
After the glass substrate 2 is automatically conveyed to the upper side, as shown in FIG. 4, the XY drive device 21 is operated to set an arbitrary coating position on the glass substrate 2 to the first detection lever 18 of the detection probe 18.
Face the tip of a. Then, the second Z drive device 1
3 is operated to lower the detection probe 18, and the tip of the first detection lever 18a is brought into contact with the glass substrate 2. Thereby, the height of the glass substrate 2 at that position is detected.

After that, the detection probe 18 is moved in the X and Z directions to bring the tip of the second detection lever 18b into contact with the tip of the discharge nozzle 15a of the syringe 15.
Thereby, the height of the discharge nozzle 15a is detected. Then, the difference between the height of the glass substrate 2 and the height of the ejection nozzle 15a is calculated.

The above-described height detection work is carried out at about 10 locations in the vicinity of the application route R of the adhesive 3 shown in FIG. For this purpose, the XY drive device 21 is operated to position each measurement point on the glass substrate 2 at a position relative to the detection probe 18.

After detecting the difference between the height of the glass substrate 2 and the height of the discharge nozzle 15a at each measurement point, the controller 23
Calculates and stores the descending amount of the discharge nozzle 15a along the coating path R so that the gap G between the discharge nozzle 15a and the glass substrate 2 becomes equal at each measurement point.

Generally, the value of the gap G is 50 ± 10 μm.
(40 to 60 μm) is an allowable range, and within this range, the adhesive 3 can be supplied in a width and a coating amount that function as a sealing material for liquid crystal sealing. In the adhesive application device, one pitch (2 mm) of the ball screws of the first and second Z-direction driving devices 12 and 13 is divided into 4000 pulses, so that the accuracy is at least 0.5 μm / 1 pulse. The detection probe 18 and the syringe 15 can be driven. If there is a maximum error of 5 pulses in this positioning, the positioning error of the detection probe 18 and the syringe 15 is ± 2.5 μm.

Further, since the detection probe 18 and the syringe 15 are driven by separate Z-direction driving devices 12 and 13, the positioning error between the detection probe 18 and the syringe 15 is 2.5 μm × 2 = 5 μm. . On the other hand, each of the first and second detection levers 18a and 18b of the detection probe 18 has an error of ± 2 μm at maximum as described above, so that the total error becomes 4 μm.

Therefore, the error range between the first and second Z-direction driving devices 12 and 13 and the detection probe 18 can be kept within ± 10 μm (5 μm + 4 μm = 9 μm) at the maximum. When the glass substrate 2 has high accuracy and the thickness variation (shape accuracy) is 3 to 5 μm,
If only the variation (20 to 30 μm) in the thickness of the glass substrate due to the difference in the rod (rolling) is detected, it is only necessary to measure at two to three points on the surface of the glass substrate 2, and the adhesive 3 within the predetermined error range. Can be satisfactorily applied.
The variation in the thickness (height) of the glass substrate 2 due to the difference in the rod can be easily detected by the detection probe 18.

After the above-described height detection and calculation are completed, the XY drive device 20 is driven to move the glass substrate 2 so that the discharge nozzle 15a moves along the predetermined path R with respect to the glass substrate 2. To move. At the same time, the discharge pump 30 is operated to supply compressed gas at a predetermined flow rate and supply it to the syringe 15 through the supply pipe 15b. As a result, the adhesive filled in the syringe 15 is discharged from the discharge nozzle 15a and applied onto the glass substrate 2.

At this time, the compressed gas supplied from the syringe 15 and the discharge pump 30 is kept at a predetermined temperature by the first and second electric heaters 32 and 34, respectively. As a result, the adhesive in the syringe 15 is also kept at a predetermined temperature and its viscosity is about 40,000 to 60,0.
The viscosity is maintained suitable for application of 00cP. Therefore, during the above-mentioned application process, the viscosity of the adhesive does not change with the passage of time, and the adhesive is always applied to the glass substrate 2 with a predetermined width and application amount.

After the application of the adhesive is completed, the other glass substrate is positioned with respect to the glass substrate 2 to which the adhesive has been applied, and they are bonded to each other. Subsequently, these glass substrates are heated while applying pressure in the bonding direction to cure the adhesive, and then liquid crystal is sealed in a region A (FIG. 5) surrounded by the adhesive on the glass substrate 2.

According to the adhesive coating device constructed as described above, the compressed gas supplied from the syringe 15 and the discharge pump 30 is kept at a predetermined temperature by the temperature adjusting mechanism 40 during the coating process. , Thereby the syringe 15
The adhesive inside is also maintained at an appropriate viscosity. Therefore, it is possible to prevent the viscosity of the adhesive from changing with the passage of time, and it is possible to maintain the amount of adhesive applied by the discharge nozzle 15b uniform over a long period of time.

As a result, variations in the amount of adhesive applied can be reduced, and the product yield can be improved. Also,
Since the viscosity of the adhesive can be kept constant, it is possible to reduce the frequency of replacement of the adhesive as compared with the conventional method, reduce the waste of the adhesive, and further improve the production efficiency of the adhesive coating device. Becomes

The present invention is not limited to the above-described embodiments, but can be variously modified without changing the gist of the invention. For example, the adhesive used is not limited to the above-mentioned epoxy resin-based thermosetting adhesive and can be changed as necessary. Needless to say, the heat retention temperature by the temperature adjusting mechanism can be appropriately changed according to the type of adhesive used.

In the above embodiment, the glass substrate 2 side is driven in the XY directions for coating, but the syringe 15, the discharge nozzle 15a and the detection probe 18 side are X side.
It may be driven in the Y direction. Furthermore, syringe 1
5 and the discharge nozzle 15a are provided so as to be integrally driven up and down, but it is also possible to connect the syringe and the discharge nozzle by a flexible tube and drive only the discharge nozzle 15a up and down.

[0040]

As described in detail above, according to the present invention, the adhesive in the syringe can be maintained at a desired viscosity for a long time by the temperature adjusting means, whereby
It is possible to always apply the adhesive in a predetermined application amount, and it is possible to provide an adhesive application device that can improve the yield of products and the production efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view showing an entire adhesive applying device according to an embodiment of the present invention.

FIG. 2 is a side view schematically showing a main part of the adhesive application device.

FIG. 3 is a diagram showing a relationship between temperature and viscosity of an adhesive.

FIG. 4 is a side view for explaining the operation of the detection probe of the adhesive application device.

FIG. 5 is a perspective view showing an adhesive application path by the adhesive application device.

[Explanation of symbols]

2 ... Glass substrate, 3 ... Adhesive agent, 12 ... 1st Z direction drive device, 15 ... Syringe, 15a ... Discharge nozzle, 15b ...
Air supply pipe, 18 ... Detection probe, 20 ... Holding table, 23 ... Control part, 30 ... Air supply pump, 32 ... First electric heater, 34 ... Second electric heater, 40 ... Temperature adjusting mechanism.

Claims (3)

[Claims] 1. A syringe filled with an adhesive, a discharge nozzle connected to the syringe, an air supply means for supplying a compressed gas to the syringe to discharge the adhesive from the discharge nozzle, An adhesive application device comprising: a temperature adjusting unit that adjusts the temperature of the compressed gas supplied from the unit and the temperature of the syringe to maintain the adhesive in the syringe at a predetermined viscosity. 2. An adhesive application device for applying an adhesive for sealing to a predetermined portion of one glass substrate when a pair of glass substrates constituting a liquid crystal panel are attached to each other, and a holding portion for holding the glass substrate. A syringe filled with the adhesive, a discharge nozzle connected to the syringe, and a nozzle drive for moving the syringe and the discharge nozzle along a predetermined path with respect to the glass substrate held by the holder. Means for supplying compressed gas to the syringe to discharge the adhesive from the discharge nozzle; adjusting the temperature of the compressed gas supplied from the gas supply means and the syringe; An adhesive application device, comprising: a temperature adjusting means for maintaining the agent at a predetermined viscosity. 3. The temperature adjusting means includes a first heater provided in an air supply passage extending between the air supply means and the syringe, and a second heater provided around the syringe.
The controller for controlling the first and second heaters, the adhesive application device according to claim 1 or 2.