JP5286775B2 - Paste applicator - Google Patents

Description

The present invention relates to a paste application machine for applying the line pattern on the substrate surface.

  In recent years, LCD panels have become larger and more accurate, and a seal dispenser that linearly applies a sealing material for sealing liquid crystal between its glass substrates has a higher speed to reduce tact time. Thus, there is a demand for higher accuracy in the cross-sectional area of coating, which becomes more difficult. For this reason, the adjustment for obtaining the operating conditions becomes more difficult and takes time.

  In Patent Document 1, as a coating adjustment method, one parameter selected from the group consisting of a cross-sectional area, a coating line width, a coating height, and a coating diameter related to a drawing line shape is measured. When the pressure exceeds the allowable range, it is disclosed that the amount of pressurization of the liquid is increased or decreased by a shift pressure value that has been input in advance. In Patent Document 2, the discharge pressure is measured in advance according to the moving speed of the coating nozzle and stored in a memory, the moving speed is measured, and the discharge pressure is controlled in accordance with the measured value. It is disclosed.

Japanese Patent No. 3877038 JP 2000-31171 A

  In Cited Document 1, the coating is performed once, the line width and the like are measured, and when the value exceeds the allowable value, the coating pressure at the next coating is changed. There is a great possibility that the substrate and paste are likely to be wasted.

  In the method of Cited Document 2, the relationship between the moving speed and the application pressure is obtained and controlled in advance, but fluctuation due to disturbance cannot be prevented.

  If the coating cross-sectional area is not uniform at any position of the linear pattern, when two glass substrates for sealing the liquid crystal are bonded together, they may protrude outside the inner liquid crystal side or outside the glass substrate, There is a risk of leakage from a location with poor sealing performance, and it is necessary to achieve uniform application.

An object of the present invention is not applied troublesome adjustment, there is provided a can Ru coating cloth device strongly applied to fluctuation due to disturbance.

A table for placing a substrate on a pedestal, which can move the portal frame which is movably installed in one direction across the table, the direction perpendicular to the moving direction of the portal frame is provided on the portal frame a coating head, a syringe for containing the paste of the coating head, a pneumatic means for supplying air pressure to the syringe, the nozzle is a discharge port provided in a syringe, from a pressurized strong point nozzle air pressure to the syringe while moving the coating head for applying a paste, portal frame and paste applying machine and a control means for performing pressure control of the movement control and pneumatic means of the coating head, the speed measuring means for measuring a moving speed of the portal frames and the coating head when provided a pressure measuring means for measuring the air pressure of the pneumatic means, the control means, the speed measuring means at the time the remaining amount of the paste in the syringe is very small Based on the results fine pressure measuring means has measured, characterized and Turkey to the switching control pressure command value in multiple stages so as to hold the coated sectional area overlapping the pressure response curve to the speed change curve constant.

  According to the present invention, by adjusting the curvature of the speed change and the curvature of the pressure response change, it is possible to easily adjust the application cross-sectional area of the seal dispenser.

  FIG. 1 shows a schematic diagram of the overall configuration of a coating apparatus to which the present invention is applied.

  A table 1 for mounting and holding a substrate on a gantry not shown is provided. The frame is provided with linear rails extending in the X direction on both sides of the table 1. On the linear rail, a gantry (gate frame) 3 having a drive mechanism (X motor) at its leg is provided. A linear rail is provided on the frame (longitudinal direction (Y direction)) located on the upper part of the table 1 of the portal frame 3 and is provided with a drive mechanism (Y motor) for moving on the linear rail. The coating head 4 is provided. The application head 4 is provided with a syringe 5 containing a sealing material (paste) so as to be attached and detached. A pipe for supplying CDA from a CDA (Clean Dry Air) source (pneumatic pressure source 6) is connected to the syringe 5. The pipe or syringe 5 is provided with a pressure gauge 10 for measuring pressure. By supplying CDA while measuring the pressure in the syringe 5 from the air pressure source 6, the paste 8 is applied to the linear pattern from the nozzle 7. Although not shown, the coating head 4 has a moving table for moving the syringe 5 up and down (Z-axis direction) and a sensor for measuring the distance between the discharge port (nozzle 7) of the syringe 5 and the glass substrate 2. It is provided. Further, a camera (not shown) for measuring the position and orientation of the glass substrate placed on the table 1 and observing a plurality of alignment marks provided on the glass substrate are provided. Furthermore, the portal frame 3 and the drive mechanism of the coating head 4 are provided with a speedometer (not shown) for measuring the speed. Based on a signal from a pressure gauge 10 for measuring the supply pressure from the speedometer and the pneumatic pressure source, a control means 9 is provided for performing air pressure control and alignment control.

  In FIG. 1B, the application cross-sectional area of the sealing material 8 applied from the nozzle 7 on the glass substrate 2 is indicated by hatched portions. FIG. 1C shows the relationship between the application pressure or application speed and the cross-sectional area of the applied sealing material.

  As shown in FIG. 1C, the coating cross-sectional area tends to decrease as the coating speed increases and increases as the coating pressure increases. Therefore, in order to make the coating cross-sectional area uniform, it is necessary to decrease the coating pressure when the coating speed is low, and increase the coating pressure when the coating speed increases.

  Therefore, in the vicinity of the center of the straight line where the coating speed is maximum, find the coating pressure that will give the necessary cross-sectional area under the conditions of the nozzle diameter, coating gap, seal material, etc. to be used. The application cross-sectional area can be made constant by making the ratio of the above constant. However, there is a time lag between the application pressure response and the movement speed response. Therefore, in order to keep the coating cross-sectional area constant at all times, control may be performed so that the speed change curve is superimposed on the pressure response curve.

  FIG. 2 shows the relationship between the pressure response curve and the speed change curve. 2A shows a conventional response curve, and FIG. 2B shows a response curve according to the present invention.

  As shown in FIG. 2A, the response of the coating pressure changes sharply at the beginning of rising and at the beginning of falling, but has a characteristic that it gradually changes as the target pressure or end point pressure is approached. For this reason, when trying to match the rising start side and the falling start portion from the target value with a speed change curve provided with an equivalent curvature, either of them does not match. Further, when trying to match the rising side and the falling side with different curvatures, the seal material cannot follow the movement of the nozzle due to a speed change in accordance with a sharp change at the beginning of rising and at the beginning of falling, and disconnection is likely to occur. Therefore, as shown in FIG. 2B, it is possible to follow the coating speed by switching and controlling the pressure command value in multiple stages. By controlling the pressure command value to be switched in multiple stages, as shown in the figure, the pressure change time is apparently sufficiently longer than the pressure response time when switching in a single stage. This makes the curvature at the beginning and end of the pressure change almost equal to the curvature of the speed change, regardless of the rise and fall of the speed change, and the pressure responsiveness due to the change in the remaining paste amount in the syringe The change was controlled so that the change in was small. At this time, when the pitch of the change of the pressure command value is made multistage, the pitch may be finely changed so as to be apparently continuous.

FIG. 3 (a) shows the relationship between the pressure response time / response delay and the pressure switching command time with the remaining paste amount in the syringe as a parameter. In general, when a pressure command value is issued in a single stage, the target value is reached vertically. That is, at the time of single stage switching, the response switching command time is zero. For example, the time from when the target pressure value is divided into two and given the first step command value (pressure value smaller than the target value) until the next target pressure command value is given is the response switching command time It is called. That is, the time from when the first-stage command is given until the final target pressure command value is given is referred to as the pressure switching command time. At this time, in order to make the response curve as smooth as possible, it is better to increase the number of times of switching. FIG. 3B shows the difference in response time depending on the remaining amount of paste in the syringe on the vertical axis and the pressure switching command time on the horizontal axis. As the pressure switching command time is lengthened, the pressure response time increases and the pressure response time approaches the pressure switching command time, but the response delay becomes conversely small (FIG. 3A). In addition, the response time and response delay become larger when the remaining amount of the coating material is small than when it is full (FIG. 3A). The difference between the response delay when the coating material remaining amount is small and when the coating material is full becomes smaller as the pressure switching command time is increased (FIG . 3A) . Thus, if the pressure switching time is sufficiently longer than the pressure response time when switching in a single stage, the change in pressure response due to the change in the remaining amount of paste in the syringe is reduced.

  The seal pattern of the LCD panel is a rectangle having a minute R at the corner, and decelerates before the corner and accelerates after passing the corner in order to adjust the coating shape of the corner. In addition, in order to adjust the start / end shape, the vehicle accelerates at the start and decelerates at the end.

  An embodiment of the present invention will be described with reference to FIG.

  FIG. 4A shows an example of the sealing material linear pattern. As shown in the figure, the target linear pattern is a closed rectangle with a minute R at each corner. FIG. 4B shows an example of coating pressure in pressure multistage switching and motor speed control for movement in the XY directions when the pattern shown in FIG. 4A is applied.

As shown in FIG. 4 (a), the coating is first applied in the X direction while accelerating from the starting point (intermediate point of the straight line portion) and decelerated before the first corner. At this time, the application pressure is switched in multiple stages so as to overlap the speed in the X direction. At the first corner, the X motor decelerates and the Y motor accelerates, but the coating speed is constant.
Accordingly, the coating pressure is also constant. After exiting the corner, the Y motor further accelerates and decelerates before the second corner. After exiting the first corner, the application pressure is controlled to change following the speed change of the Y motor. At the second corner, the Y motor decelerates and the X motor accelerates in the opposite direction, but the coating speed is constant. At this time, the coating pressure is controlled to be constant. After exiting the corner, the X motor further accelerates and decelerates before the third corner. That is, when passing through the second corner, the speed of the X motor is reversed as shown in the figure, but the coating pressure gradually increases. However, the absolute value of the speed and the increase in the coating pressure are controlled to overlap. At the third corner, the X motor decelerates and the Y motor accelerates in the reverse direction, but the coating speed is constant and the coating pressure is also controlled to be constant. After exiting the corner, the Y motor further accelerates and decelerates before the fourth corner. After exiting the corner, the coating pressure is controlled to overlap the absolute value of the Y motor. In the fourth corner, the Y motor decelerates and the X motor accelerates in the positive direction, but the coating speed is constant. After exiting the corner, the X motor further accelerates, decelerates before the end point, and the coating of one pattern is completed. The coating pressure is basically adjusted so that the absolute value of the coating speed obtained by combining the X motor speed and the Y motor speed overlaps the graph shape. The application pressure is constant at each corner, but the acceleration / deceleration section on the straight lines before and after it changes sharply at the beginning of the rise and at the beginning of the fall by controlling the application pressure command value in multiple steps or apparently continuously. However, it becomes possible to artificially control the pressure response curve that gradually changes as the target pressure is approached, and it is easy to match with the speed change curve having the same curvature up and down.

It is explanatory drawing of the sealing dispenser structure for LCD, and application | coating cross-sectional area. It is the figure which showed the relationship of the coating speed in switching of a pressure command value. FIG. 6 is a diagram for explaining a relationship between a falling pressure switching command time and a pressure response time in pressure switching. It is explanatory drawing of a sealing material linear pattern example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Table, 2 ... Board | substrate, 3 ... Portal frame, 4 ... Application | coating head, 5 ... Syringe, 6 ... Air pressure source, 7 ... Nozzle, 8 ... Paste, 9 ... Control means, 10 ... Pressure gauge.

Claims (1)

A table on which a substrate is placed on a gantry, a portal frame that can be moved in one direction across the table, and a moving direction of the portal frame that is provided on the portal frame and moves in a direction perpendicular thereto a coating head capable of, a syringe for containing a paste of the coating head, a pneumatic means for supplying air pressure to the syringe, and the nozzle is a discharge port provided in the syringe, air pressure while moving the coating head for applying the paste from the nozzle in addition to the syringe, the paste applying machine and a control means for performing pressure control of the movement control and the pneumatic means of the gantry frame and the coating head,
A speed measuring means for measuring a moving speed of the gantry frame and the coating head, and a pressure measuring means for measuring the air pressure of the pneumatic means is provided,
The control means overlaps the pressure response curve with the speed change curve based on the result of measurement by the speed measurement means and the pressure measurement means when the remaining amount of the paste in the syringe is very small, and calculates the coating cross-sectional area. paste applying machine according to claim and Turkey to switching control in the multi-stage pressure command value so as to hold constant.

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