JPH0784268A - Method for plotting sealing material - Google Patents

Abstract

PURPOSE:To provide the method for plotting a sealing material by controlling a discharge rate and discharge position of the sealing material to be dispensed and speeding up application. CONSTITUTION:This method for plotting the sealing material comprises impressing a prescribed air pressure A from an air source disposed outside to a nozzle storing the sealing material to discharge the sealing material 4 onto a substrate to be coated, thereby plotting the sealing material in a required pattern on the substrate to be coated. A high-pressure air pulse Ap higher than the prescribed pressure is inputted at an application start point P1 of the sealing material 4 to the nozzle from the air source and a vacuum pulse Vp is impressed thereto at an application stop point P2 of the sealing material, by which the discharge rates of the sealing material 4 at the application start point P1 and application stop point P2 of the sealing material are approximately equaled and the application position thereof is controlled to the prescribed position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing agent application technique, and in particular, dispenses a sealing agent (adhesive) for sealing and joining between upper and lower substrates of a liquid crystal display device to a predetermined portion in a required amount. The present invention relates to a sealing agent drawing method.

[0002]

2. Description of the Related Art For example, in a variety of electronic devices in which a flat substrate such as a liquid crystal display device is attached to a predetermined portion of the peripheral edge thereof with a sealant in a specific pattern, the seal is applied by screen printing. Was common.

Particularly, in a liquid crystal display device having various functional films including an alignment film on its inner surface, the sealing agent is discharged from a nozzle and continuously applied in order to avoid contact between the applied sealing agent and the functional film. A so-called dispense coating method has come to be used.

FIG. 11 is a schematic view for explaining a schematic structure of a liquid crystal display element, in which 1 is a glass substrate (1a is an upper substrate, 1a is an upper substrate,
b is a lower substrate), 4 is a sealant (epoxy resin adhesive, etc.), and 4a is a liquid crystal injection opening.

The upper substrate 1a and the lower substrate 1b are formed by applying a sealant 4 to the peripheral portions of the upper substrate 1a and the lower substrate 1b and bonding the two together, and injecting a liquid crystal from the liquid crystal injection opening 4a between the adhered gaps for sealing.

FIG. 12 is an enlarged view of a corner portion of the sealant after adhesion, in which a conductive paste (silver-epoxy resin system) is applied to the corner portion 4a after application of the sealant 4.
When the sealant 4 hardens and the upper and lower substrates are bonded together,
The conductive paste applied to the corner portions 4b is also cured to electrically connect the conductive layers formed on the upper and lower substrates 1a and 1b.

FIG. 13 is an enlarged view of the principal part for explaining an example of a conventional sealant application pattern at the corner portion by screen printing and the sealant pattern when the upper and lower substrates are bonded together. The width of the sealant at the corner portion is shown in FIG. In order to secure a space for applying the above-mentioned conductive paste at the corner portion when enlarging the above and applying the sealant, as shown in (a), shapes such as a and b are given. Then, when the upper and lower substrates are bonded together, this sealant pattern is spread between the substrates, and as a result, the width of the corner portion is equal to the width of the linear portion and the conductive paste of The coating space can be secured.

However, in such screen printing,
Due to the above-mentioned problems, dispense coating has been adopted.

FIG. 14 is a schematic diagram for explaining a schematic structure of a conventional dispense coating apparatus. 10 is an XYZ table movable in X, Y, and Z directions, 11 is a glass substrate of a liquid crystal display element, and 12 is a glass substrate. Nozzle arm, 13 is a nozzle, 14 is an air source, 15 is a sensor arm, and 16 is a gap sensor.

In FIG. 1, a glass substrate 11 of a liquid crystal display element is fixedly held on an XYZ table 10, and a nozzle arm 12 holding a nozzle 13 for dispensing a sealing agent above the glass substrate 11 and a nozzle 13. Gap sensor 16 for maintaining a constant gap between
The sensor arm 15 holding the is arranged.

A predetermined sealant is stored in the nozzle 13 in advance, and an air source 14 for applying a predetermined pressure to the sealant is connected to the nozzle 13.

This dispenser coats the nozzle 13 while moving the XYZ table 10 in the X and Y directions.
The sealing agent is dispensed on the periphery of the glass substrate 11. During this dispensing, the sensor 16 that moves on the glass substrate 11 at a position preceding the nozzle 13 measures the gap between the surface of the glass substrate 11 and the nozzle 13 so that the gap is always constant. The position of the XYZ table 10 is adjusted in the Z direction.

In some cases, instead of the XYZ table, the nozzle arm 12 and the sensor arm 15 are moved in the XYZ directions.

In this type of dispenser, the sealant is applied by applying a constant pressure applied from the air source 14 to the sealant to dispense it. Therefore, the dispensing of the sealing agent becomes a so-called one-stroke drawing pattern. The discharge amount of the sealing agent during drawing is constant, and the amount of the sealing agent dispensed on the glass substrate 11 is controlled to be constant by keeping the gap constant.

As a disclosure of the prior art relating to this type of dispense coating apparatus, Japanese Patent Laid-Open No. 2-19 is available.
8417, JP-A-1-200228, JP-A-63-177113, and JP-A-63-19201.
9 and JP-A-63-236008.

[0016]

In the dispense coating device according to the above-mentioned prior art, the discharge amount of the seal agent greatly changes when the discharge of the seal agent is started and stopped. for that reason,
The spread of the sealant when the upper and lower substrates are bonded differs between when the discharge is started and when the discharge is stopped, and the increase in the coating amount at the corner deteriorates the characteristics of the conductive paste separately applied to the corner. There was a problem that it would end up.

FIG. 15 is an explanatory diagram of a coating state of a sealing agent by the above-mentioned conventional dispense coating apparatus, in which air pressure applied to a nozzle is shown, and (b) shows a shape of the sealing agent applied to a glass substrate.

As shown in the figure, even when a predetermined level A of air pressure is applied to the nozzle at the coating start point, the time at which the sealant is actually discharged from the nozzle onto the glass substrate is delayed by d _1. Also, even if the air pressure is released when application is stopped, the residual pressure causes the sealing agent to be discharged from the nozzle to a position delayed by d ₂ , and the amount of sealing agent discharged at this application stop position increases It will be applied to the position beyond the position.

Therefore, it is difficult to draw an extremely short straight line, and since the discharge amount of the sealant at the corner is similar to that of the straight line, the amount of the sealant applied to the corner increases, The bonding of the upper and lower substrates increases the spread of the sealant. Therefore, there is a problem in that the conductive paste applied to the above-mentioned corner portion mixes with the sealant and deteriorates the conductive connection characteristics of the upper and lower substrates.

It is an object of the present invention to solve the above-mentioned problems of the prior art, to provide a sealing agent drawing method which controls the discharge amount of the dispensed sealing agent and speeds up the coating.

[0021]

In order to achieve the above object, the invention of claim 1 provides a nozzle storing a sealant,
In a sealant drawing method for drawing a predetermined pattern of the sealant on the substrate to be coated by applying a predetermined air pressure from an externally provided air source and discharging the sealant onto the substrate to be coated , By applying a high-pressure air pulse higher than the predetermined pressure to the nozzle from the air source at the start of application of the sealing agent and applying a vacuum pulse at the application stop point of the sealing agent, The discharge amount of the sealing agent is made substantially equal at the start of application of the agent and the stop point of application of the sealing agent, and the application position is controlled to a predetermined position.

Further, according to the invention of claim 2, a predetermined air pressure is applied to the nozzle storing the sealant from an external air source to discharge the sealant onto the substrate to be coated. In a sealant drawing method of drawing a sealant in a desired pattern on the substrate to be coated, the discharge of the sealant is stopped by applying a vacuum pulse to the nozzle immediately before the corner at the corner of the drawing pattern. Then, the application is interrupted, and immediately after the corner portion, a high-pressure air pulse is applied at a pressure higher than the predetermined pressure to start the discharge of the sealant, and the application is restarted, and then the predetermined air pressure is applied. According to the above, the amount of the sealant coating required for bonding the corner portion is controlled.

Further, according to the invention of claim 3, a predetermined air pressure from an external air source is applied to the nozzle storing the sealant to discharge the sealant onto the substrate to be coated. In a sealing agent drawing method for drawing a sealing agent in a desired pattern on the substrate to be coated, the pattern to be drawn is composed of a combination of two sealing agent application elements, a straight line and a dot.

According to a fourth aspect of the present invention, a predetermined air pressure is applied from an external air source to the nozzle storing the sealant, and the sealant is discharged onto the substrate to be coated. In a sealing agent drawing method for drawing the sealing agent in a desired pattern on the substrate to be coated, the pattern to be drawn is composed of a combination of two sealing agent applying elements, a straight line and a dot, and the sealing agent applying element is Control of the discharge amount of the sealing agent for application,
From the air source, a high-pressure air pulse higher than the predetermined pressure is input to the nozzle at the time of starting the application of the sealant, and a vacuum pulse is applied at the point where the application of the sealant is stopped. It is characterized in that it is performed by changing the gap between the substrate to be coated.

The present invention appropriately controls the discharge amount by the above-mentioned high pressure pulse and vacuum pulse, the discharge amount control by the change in the gap between the nozzle and the substrate to be coated, and the change in the relative speed between the nozzle and the substrate to be coated. By combining,
Various complicated patterns can be drawn.

[0026]

With the configuration of the invention of claim 1, there is no delay in applying the sealing agent at the start of applying the sealing agent, and
It is possible to prevent the discharge amount of the sealing agent from increasing at the sealing agent application opening stop point, and it is possible to perform substantially uniform application from the sealing agent application start point to the application opening stop point at a predetermined position.

According to the configuration of the invention of claim 2,
By controlling the coating amount of the sealing agent required for bonding the corner portion, it is possible to prevent the sealing agent from spreading in the corner portion and secure a coating area of the conductive paste to be separately coated in the corner portion.

Further, according to the configuration of the third aspect of the invention, the pattern of the drawing portion other than the straight line can be accurately formed.

Further, according to the configuration of the invention of claim 4, the coating amount of the sealing agent can be accurately controlled.

[0030]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is an explanatory view of the first embodiment of the sealant coating method according to the present invention, in which (a) is the air pressure applied to the nozzle and (b) is the sealant applied to the substrate to be coated. The shape is shown.

In FIG. 1A, A is a predetermined air pressure level for dispensing the sealant from the nozzle, and H is H.
The predetermined air pressure level A high pressure air pressure than, L is the predetermined low vacuum air pressure than the air pressure level A, O is the reference level of the air pressure 0 the sealant is not dispensed from the nozzle, A _P is pressure Air pulse, V _P is a vacuum pulse.

A high-pressure air pulse A having a level H higher than a predetermined air pressure level A at a coating start point P ₁ which is a position where coating of a sealant on a substrate to be coated (for example, a glass substrate of a liquid crystal element) shown in the figure is started. _{Apply P} to the nozzle. As a result, the sealant 4 is dispensed onto the substrate to be coated without delaying the coating at the coating start point P ₁ .

Thereafter, the dispensing is continued at a predetermined air pressure level A, and the vacuum air pressure level L is reached at the coating stop point P _2.
The vacuum pulse V _P is applied. As a result, the sealant 4
Dispenses beyond the coating stop point P ₂ without coating.

As described above, according to this embodiment, the sealant 4 is applied to the substrate to be coated in the range from the coating start point P ₁ to the coating stop point P ₂ as shown in FIG. It is applied in a substantially uniform amount, and deviation from the predetermined application range as described in FIG. 15 and uneven application of the sealing agent are avoided.

FIG. 2 is an explanatory view of a second embodiment of the sealant coating method according to the present invention, in which 1b is a substrate to be coated (for example, a lower glass substrate of a liquid crystal element), 4-1 is a coated sealant. Linear elements, 4-2 are applied sealant point elements.

The sealant linear element 4-1 and the sealant point element 4-2 are formed by discharging and applying the sealant in the same manner as in the first embodiment. The application is interrupted at the corners, and the fine application is performed at the plurality of sealant point elements 4-2.

FIG. 3 is an explanatory view of the state of the sealant when another substrate (for example, the upper glass substrate of the liquid crystal element) 1a is bonded to the substrate 1b having the sealant applied in FIG. Therefore, the sealant linear element 4-1 spreads out at the corners and continues to form a frame-shaped seal 4-1 '.
Becomes Similarly, the sealant point element 4-2 also spreads to form a continuous linear pattern 4-2 '.

As described above, according to this embodiment, the sealant pattern can be formed in a desired shape.

FIG. 4 is an explanatory view of a method of controlling the air pressure applied to the nozzle for discharging the sealant to each pattern of the sealant linear element and the sealant point element in the second embodiment of the present invention. , (A) is an air pressure application timing diagram, and (b) is a pattern diagram of the sealing agent to be discharged.

In the figure, the sealant linear element 4
-1 applies a high pressure air pulse A _P in its application start point,
Dispensing is continued at a predetermined air pressure level A, and a vacuum pulse V _P is applied to the nozzle at the coating stop point. The sealant point element 4-2 applies the high-pressure air pulse A _P at the application start point and then applies the vacuum pulse V _P to the nozzle.

In this way, by controlling the air pressure applied to the nozzle, it is possible to obtain the coating pattern of the sealing agent as shown in FIG.

FIG. 5 and FIG. 6 are explanatory views of a modified example of the method of applying the sealant on the corner portion of the seal pattern.

In FIG. 5A, the discharge amount is reduced by making the gap between the nozzle and the substrate to be coated (lower glass substrate) slightly smaller at the end of the sealant linear element 4-1, that is, at the corner. A sealant point element 4- for securing an area for a separately applied conductive paste
2 is applied.

When the substrate to be coated (lower glass substrate) coated with the sealant in this manner is attached to the substrate to be coated (upper glass substrate) on the other side, a linear pattern 4-as shown in FIG. A seal pattern in which 1'and 4-2 'are continuous is obtained.

Further, in FIG. 6A, the gap between the nozzle and the substrate to be coated (lower glass substrate) is made to be smaller than the discharge limit at the end, that is, the corner portion of the sealant linear element 4-1. To stop the discharge amount, or to stop the discharge by applying the above-mentioned vacuum pulse,
A sealant point element 4-2 for securing a region for a separately applied conductive paste is applied.

When the other substrate to be coated (upper glass substrate) is attached to the substrate to be coated (lower glass substrate) coated with the sealant in this way, a linear pattern 4-as shown in FIG. A seal pattern in which 1'and 4-2 'are continuous is obtained.

FIG. 7 is a schematic configuration diagram of a sealant coating device for explaining the control of the discharge amount of the sealant by changing the gap between the nozzle and the substrate to be coated, and 1b is the substrate to be coated (lower glass substrate). 2 is a nozzle, 3 is a gap sensor,
4 is the applied sealant, and 7 is an air pressure control device.

8 and 9 are explanatory views of the sealing agent discharge control according to FIG. 7, and the same reference numerals as those in FIG. 7 correspond to the same portions.

In FIG. 7, a predetermined amount of sealant is stored in the nozzle 2 and is set up and down in the arrow direction by a mechanism (not shown). Further, in the nozzle 2, the discharge amount of the sealing agent discharged from the nozzle 2 is set by the air pressure introduced from the air pressure control device 7.

As shown in FIG. 8, when the gap between the substrate (lower glass substrate) 1b to be coated and the nozzle 2 is G ₁ , the sealant 4 is moved by the air pressure control device 7 and the nozzle 2. The amount determined by the above substrate to be coated (lower glass substrate)
1b is applied.

On the other hand, as shown in FIG. 9, the gap between the coated substrate (lower glass substrate) 1b and the nozzle 2 is G
When the sealing agent 4 is narrowed to ₂ , the sealing agent 4 is applied to the coated substrate (lower glass substrate) 1b in an amount smaller than the discharge amount shown in FIG.

As described above, the discharge amount of the sealing agent can be controlled by changing the gap between the nozzle and the substrate to be coated.

If this gap is made smaller than a certain amount, the discharge of the sealant 4 from the nozzle 2 is stopped.

In the sealant coating device of FIG. 7, the gap between the nozzle and the substrate to be coated is measured by the gap sensor 3 installed in the nozzle, and this is fed back to the lifting mechanism of the nozzle and based on the set nozzle gap value. The sealing agent is discharged while keeping the gap constant. When changing the discharge amount of the sealing agent, the gap control is performed based on the same gap by changing the set nozzle gap value.

FIG. 10 is an explanatory view of the relationship between the size of the gap and the discharge amount of the sealing agent, where the horizontal axis represents the gap height (gap size) and the vertical axis represents the discharge amount of the sealing agent from the nozzle. Take and show.

The conditions shown in the figure are that the nozzle diameter is 0.2 mm,
The air pressure is 294 kpa and the coating speed is 30 mm. Although the discharge amount of the sealing agent is also affected by the viscosity thereof, here, a general epoxy resin used for sealing the liquid crystal element is used.

As shown, the gap size is 4
When it is 0 μm or less, the discharge of the sealing agent is stopped. And
In the range of 40 to 100 μm, the discharge amount of the sealing agent changes depending on the size of the gap. Further, when it is 100 or more, the relationship between the gap and the ejection amount does not change much.

In this way, the amount of the sealing agent to be discharged can be controlled by controlling the gap.

[0060]

As described above, according to the present invention,
There is no delay in applying the sealing agent at the start of the application of the sealing agent, and it is possible to prevent an increase in the discharge amount of the sealing agent at the point where the sealing agent is opened, so that the sealing agent can be applied from the starting point to the stopping point. Uniform coating can be applied in place.

Further, by controlling the amount of the sealant applied for bonding the corners, the spread of the sealant in the corners can be prevented, and a conductive paste application area separately applied to the corners can be secured. can do.

Further, the pattern of the drawing portion other than the straight line can be accurately formed, and the application amount of the sealant can be accurately controlled.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of a sealing agent applying method according to the present invention.

FIG. 2 is an explanatory view of a second embodiment of the sealing agent applying method according to the present invention.

FIG. 3 is an explanatory diagram of a state of the sealant when another substrate is attached to the substrate to be coated having the sealant applied in the second example of the sealant applying method according to the present invention.

FIG. 4 is an explanatory diagram of a method of controlling the air pressure applied to the nozzle for discharging the sealant into each pattern of the sealant linear element and the sealant point element in the second embodiment of the present invention.

FIG. 5 is an explanatory diagram of a modified example of a method of applying a sealant on a corner portion of a seal pattern.

FIG. 6 is an explanatory diagram of another modified example of the method of applying the sealant on the corner portion of the seal pattern.

FIG. 7 is a schematic configuration diagram of a sealant coating device for explaining control of a discharge amount of a sealant according to a change in a gap between a nozzle and a substrate to be coated.

FIG. 8 is an explanatory diagram of the sealing agent discharge control according to FIG. 7.

9 is an explanatory diagram of the sealant discharge control according to FIG. 7.

FIG. 10 is an explanatory diagram of a relationship between the size of the gap and the discharge amount of the sealing agent.

FIG. 11 is a schematic diagram illustrating a schematic configuration of a liquid crystal display element.

FIG. 12 is an enlarged view of a corner portion of the sealant after adhesion.

FIG. 13 is an enlarged view of a main part for explaining an example of a sealant application pattern at the time of pasting the upper and lower substrates with a sealant application pattern at a corner portion by conventional screen printing.

FIG. 14 is a schematic diagram illustrating a schematic configuration of a conventional dispense coating device.

FIG. 15 is an explanatory diagram of a coating state of a sealing agent by a conventional dispense coating device.

[Explanation of symbols]

 1a Upper glass substrate of liquid crystal display element 1b Lower glass substrate of liquid crystal display element 2 Nozzle 3 Gap sensor 4 Sealant.

Front page continued (72) Inventor Keiji Yajima 3300 Hayano, Mobara-shi, Chiba Hitachi Ltd. Electronic Device Division (72) Inventor Shigeru Ishida 5-2 Mukoyodai, Ryugasaki-shi, Ibaraki Hitachi Techno Engineering Co., Ltd. In-house (72) Inventor Shozo Igarashi 5-2 Koyodai, Ryugasaki-shi, Ibaraki Hitachi Techno Engineering Co., Ltd. Ryugasaki Plant

Claims (4)

[Claims] 1. A sealant is stored on a substrate to be coated by applying a predetermined air pressure from an external air source to a nozzle storing the sealant and discharging the sealant onto the substrate. In the sealing agent drawing method of drawing in a required pattern above, a high-pressure air pulse higher than the predetermined pressure is input from the air source to the nozzle at the start of application of the sealing agent to start the application of the sealing agent. By applying a vacuum pulse at the stop point, the discharge amount of the sealant at the start of applying the sealant and the discharge amount of the sealant at the stop point of application of the sealant are made substantially equal, and the application position is set to a predetermined position. A sealing agent drawing method characterized by controlling. 2. A sealant is stored on a substrate to be coated by applying a predetermined air pressure from an external air source to the nozzle storing the sealant and discharging the sealant onto the substrate to be coated. In the sealing agent drawing method of drawing a desired pattern on the above, at the corner portion of the drawing pattern, by applying a vacuum pulse to the nozzle immediately before the corner portion, the discharge of the sealing agent is stopped and the application is interrupted. , Immediately after the corner portion, by applying a high-pressure air pulse from the predetermined pressure to start the discharge of the sealant and restart its application, by applying the predetermined air pressure,
A method for drawing a sealing agent, which comprises controlling an application amount of the sealing agent required for adhering the corner portion. 3. The substrate to be coated is applied by applying a predetermined air pressure from an external air source to a nozzle storing the sealant and discharging the sealant onto the substrate to be coated. A sealing agent drawing method for drawing a desired pattern on the above, wherein the pattern to be drawn is composed of a combination of two sealing agent applying elements of a straight line and a dot. 4. The substrate to be coated is applied by applying a predetermined air pressure from an external air source to a nozzle storing the sealant and discharging the sealant onto the substrate to be coated. In the method for drawing a sealant, which is drawn in a desired pattern on the above, the pattern to be drawn is composed of a combination of two sealant application elements of a straight line and a dot, and the sealant for applying the sealant application element is formed. To control the discharge amount, a high-pressure air pulse higher than the predetermined pressure is input from the air source to the nozzle at the start of application of the sealing agent, and a vacuum pulse is applied at the application stop point of the sealing agent. At the same time, the sealing agent drawing method is performed by changing the gap between the nozzle and the substrate to be coated.