JP2015029966A - Droplet coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet coating apparatus capable of reducing a time loss resulting from adjustment of discharge quantity.SOLUTION: A droplet coating apparatus adjusts discharge quantity per one-shot of a droplet, when application to an arbitrary substrate ends, and starts the application to said substrate when said adjustment ends and when the preparation of a substrate to be next applied ends. At the time of the discharge adjustment, the flow rate at the time of feeding compressed air into a space on the lower side of a piston 7 is changed (while the feeding pressure is constant), or the stroke of a rod 8 is changed.

Description

  The present invention relates to a droplet coating apparatus that applies a predetermined amount of a liquid (droplet) such as a resin or an adhesive to an object to be coated such as a substrate.

  Regarding the droplet coating apparatus, in the electronic component industry, it is required to perform droplet coating at a high speed and with a precise coating amount (discharge amount) on an object to be coated. Japanese Patent Application Laid-Open No. H10-228688 compares a drip amount of viscous material distributed to a weight scale with a control amount stored in advance, generates an error signal, and calibrates the error signal to be within an allowable range. Disclose. Japanese Patent Application Laid-Open No. 2004-259561 discloses that in a droplet applying device (jet dispenser), a flow rate-controlled air is supplied when the plunger rod is retracted to control the retracting speed of the plunger rod, whereby the discharge port at the tip of the nozzle Disclosed is a technique for preventing air from being sucked in from.

Japanese Patent No. 4643021 Japanese Patent No. 4663894

  The operation of adjusting the droplet discharge amount is indispensable for precision coating, but from the viewpoint of high-speed coating, it is desirable that the time loss accompanying the adjustment of the discharge amount is small.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a droplet coating apparatus capable of reducing time loss due to adjustment of the discharge amount.

One embodiment of the present invention is a droplet coating apparatus. This droplet coating device
A liquid reservoir for storing the liquid to be applied;
A discharge path extending from the liquid reservoir and having a tip serving as a discharge port;
A rod whose tip reciprocates toward the discharge path in the liquid reservoir,
A piston provided on the base end side of the rod;
A cylinder containing the piston;
An urging means for urging the piston in a direction in which the rod faces the discharge path;
Piston driving means for reciprocating the piston by changing the air pressure of at least one of the spaces in the cylinder partitioned by the piston;
A discharge amount adjusting means for adjusting a discharge amount per one shot of droplets discharged from the discharge port;
When the application to a certain substrate is completed, the discharge amount is adjusted by the discharge amount adjusting means, and when the adjustment is completed and the preparation of the substrate to be applied next is completed, the application to the substrate is started.

  The discharge amount adjusting means may adjust the discharge amount by changing a stroke of the piston.

  The discharge amount adjusting means may adjust the discharge amount by changing a flow rate of air when the piston is moved backward by the piston driving means.

  The discharge amount adjusting means adjusts the discharge amount by changing the stroke of the piston, and changes the flow rate of air when the piston is retracted by the piston driving means. The second discharge amount adjustment for adjusting the discharge amount can be performed, and it is determined which discharge amount adjustment is performed or both of the discharge amount adjustments are performed according to the viscosity of the liquid to be applied. Also good.

  The supply pressure when changing the flow rate may be constant.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

  According to the present invention, it is possible to provide a droplet coating apparatus capable of reducing time loss caused by adjusting the discharge amount.

1 is a schematic configuration diagram of a droplet applying apparatus according to an embodiment of the present invention. FIG. 2 is a partially enlarged view of a configuration in which the intake port 12 and the exhaust port 13 of FIG. FIG. 3 is an explanatory diagram of the operation of the rod 8 during discharge in the droplet applying apparatus of FIG. 1. The graph which shows the relationship between the rod set stroke and discharge amount in the droplet coating device of FIG. FIG. 2 is an enlarged view of a liquid reservoir formed on the lower side from the discharge port 5 immediately before the rod 8 starts to descend in the droplet applying apparatus of FIG. 1. The graph which showed the time change of the atmospheric | air pressure of the lower space of the piston 7 about 2 types which made supply pressure constant and made flow volume large or small. The graph which showed the time change of the atmospheric | air pressure of the lower space of piston 7 about two types which made supply pressure large or small. The flowchart of the discharge amount adjustment (correction | amendment) operation | movement in the droplet application apparatus of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, process, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  FIG. 1 is a schematic configuration diagram of a droplet applying apparatus according to an embodiment of the present invention. The droplet applying device stores a liquid (resin, adhesive, etc.) to be applied in the syringe 1. A liquid passage 2 extends from the syringe 1 to the liquid reservoir 3. The inner bottom surface of the liquid pool portion 3 is a tapered surface, and a nozzle 4 as a discharge path extends downward from the tip (center of the inner bottom surface) of the tapered surface. The tip of the nozzle 4 is an ejection port 5 that ejects droplets. The liquid surface inside the syringe 1 is pressurized at a predetermined pressure, and the liquid passage 2, the liquid reservoir 3, and the nozzle 4 are filled with the liquid to be applied.

  A cylinder 6 and a piston 7 are provided above the liquid reservoir 3. A rod 8 extends from the lower surface of the piston 7 to reach the liquid reservoir 3. A spring 9 is provided above the piston 7 as urging means. The spring 9 presses the upper surface of the piston 7 and biases the piston 7 downward, that is, in a direction in which the rod 8 faces the nozzle 4 (direction in which the rod 8 descends (advances)). An annular seal 10 is provided on the outer peripheral surface of the piston 7. The seal 10 is an elastic member such as rubber and prevents air from flowing between the upper and lower spaces partitioned by the piston 7. An annular air seal 11 a and liquid seal 11 b are provided at the boundary between the cylinder 6 and the liquid reservoir 3. Both the air seal 11a and the liquid seal 11b are elastic members such as rubber. The air seal 11 a is in contact with the outer peripheral surface of the rod 8 and prevents air from leaking from the cylinder 6 to the liquid reservoir 3. The liquid seal 11 b also contacts the outer peripheral surface of the rod 8 and prevents liquid from leaking from the liquid reservoir 3 to the cylinder 6.

  An intake port 12 and an exhaust port 13 are opened on the outer peripheral surface of the cylinder 6. The intake port 12 and the exhaust port 13 communicate with the space below the piston 7 in the cylinder 6. The intake port 12 is connected to a switching valve 15 (electromagnetic switching valve) via a variable throttle valve 14. The exhaust port 13 is connected to the switching valve 15. The switching valve 15 selectively communicates with a compressed air source (not shown) or the atmosphere. The variable throttle valve 14 and the switching valve 15 are examples of piston driving means. The intake port 12 and the exhaust port 13 shown in FIG. 1 may be combined into an intake / exhaust port 16 as shown in FIG. In this case, the variable throttle valve 14 is replaced with a variable speed controller 17. The variable speed controller 17 has a variable throttle valve and a check valve (check valve) connected in parallel. The check valve is provided so that air flows in the exhaust direction. As the variable throttle valve and check valve (check valve), an electrically controlled proportional control valve is used. The electric control type proportional control valve is excellent in flow rate responsiveness to an applied current or applied voltage, and can be controlled at high speed and with high accuracy.

  A stopper end 18 is provided at the center of the upper surface of the piston 7 (the surface opposite to the surface serving as the base end of the rod 8). The stopper end 18 is a convex portion integrated with the piston 7. A variable stopper 19 facing the stopper end 18 is provided in the space above the piston 7 in the cylinder 6. The amount of protrusion of the variable stopper 19 can be adjusted by a control device (not shown). In addition, by using a mechanism using an electrically controlled proportional control valve as a control device for the variable stopper, it is possible to perform control with excellent response and high speed and high accuracy. When the stopper end 18 contacts the variable stopper 19, the ascending (retreating) position of the piston 7 is determined.

  FIG. 3 is an explanatory diagram of the operation of the rod 8 during ejection in the droplet applying apparatus of FIG. In a state where the switching valve 15 shown in FIG. 1 communicates with the atmosphere, the piston 7 is lowered (advanced) by the bias of the spring 9 until the tip of the rod 8 closes the upper opening of the nozzle 4 (FIG. 3 ( A)). When the switching valve 15 is in communication with the compressed air source from here, compressed air is supplied from the intake port 12 to the space below the piston 7 in the cylinder 6 via the variable throttle valve 14. Then, when the space exceeds a predetermined air pressure, the piston 7 rises (retreats) against the bias of the spring 9, and the tip of the rod 8 moves away from the upper opening of the nozzle 4 (FIG. 3 (A) → FIG. 3 (B)). The rising distance (stroke) of the piston 7 and the rod 8 at this time, that is, the rod setting stroke shown in FIG. 3B is determined by the protruding length of the variable stopper 19 shown in FIG. Moreover, the timing at which the piston 7 and the rod 8 start to rise can be changed by adjusting the flow rate of the variable throttle valve 14.

  Thereafter, when the switching valve 15 is brought into communication with the atmosphere, air flows out from the space below the piston 7 in the cylinder 6 through the exhaust port 13 until the space reaches atmospheric pressure. Then, the piston 7 descends (advances) again by the bias of the spring 9, and the tip of the rod 8 blocks the upper opening of the nozzle 4 (FIG. 3 (B) → FIG. 3 (C) → FIG. 3 (A)), A droplet is discharged from the discharge port 5 at the tip of the nozzle 4. The operations of the piston 7 and the rod 8 described above are the same in the configuration shown in FIG. In the configuration shown in FIG. 2, during intake, compressed air is supplied to the space below the piston 7 via the intake / exhaust port 16 at a flow rate controlled by the variable throttle valve of the variable speed controller 17. During exhaust, the space below the piston 7 is exhausted through the intake / exhaust port 16 and the check valve of the variable speed controller 17, and the space becomes atmospheric pressure.

  In the present embodiment, one or both of the following two methods are performed in order to adjust the discharge amount per one shot of the liquid droplets discharged from the discharge port 5. The first method is a change (adjustment) of the rod set stroke shown in FIG. The second method is a flow rate change (adjustment) when compressed air is supplied to the space below the piston 7. Note that the supply pressure is preferably constant when the flow rate is changed. Changing the flow rate while keeping the supply pressure constant is advantageous in that the discharge amount can be adjusted only by adjusting the flow rate with excellent responsiveness.

Discharge amount Adjustment Figure 4 by stroke changes, in the droplet applying apparatus of FIG. 1 is a graph showing the relationship between the rod set stroke ejection volume. When the rod 8 is lowered, the liquid in the liquid reservoir 3 is subjected to a force for pushing in the C direction and the D direction as shown in FIG. When the rod set stroke shown in FIG. 3B is changed, the force in the D direction is changed, and the discharge amount per one shot of the droplet discharged from the discharge port 5 is changed. Specifically, as shown in FIG. 4, the discharge amount per one shot increases as the rod set stroke is lengthened.

Discharge amount Adjustment Figure 5 by the flow rate change, just before the rod 8 starts to descend in the droplet applying apparatus of FIG. 1 is an enlarged view of the liquid pools are formed in the lower side from the discharge port 5. As shown in FIG. 5A, when the flow rate when supplying compressed air to the lower space of the piston 7 is small, the liquid pool formed on the lower side from the discharge port 5 is small. On the other hand, as shown in FIG. 5B, when the flow rate when supplying compressed air to the lower space of the piston 7 is large, the liquid pool formed on the lower side from the discharge port 5 is large. The difference in the size of the liquid pool in FIGS. 5A and 5B is caused by the difference in timing at which the piston 7 and the rod 8 start to rise.

  FIG. 6 is a graph showing the time change of the atmospheric pressure in the lower space of the piston 7 for two types with the supply pressure being constant and the flow rate being large or small. The timing at which the piston 7 and the rod 8 start to rise is the timing at which the force for raising the piston 7 due to the atmospheric pressure in the space below the piston 7 exceeds the urging force of the spring 9. Arrives early (time T1, T2 in FIG. 6). The liquid pool starts to be formed after the piston 7 and the rod 8 are raised and the upper opening of the nozzle 4 is opened, and becomes larger as time passes. For this reason, if the flow rate when supplying compressed air to the space below the piston 7 is small, the timing at which the piston 7 and the rod 8 start to rise is delayed, and therefore the liquid pool until the rod 8 starts to descend next time. The formation time is short and the liquid pool is small. For this reason, the discharge amount of the droplet when the rod 8 descends next becomes small. On the other hand, if the flow rate when supplying compressed air to the space below the piston 7 is large, the timing at which the piston 7 and the rod 8 start to rise becomes earlier, so the liquid until the rod 8 starts to descend next is reached. The pool formation time is long and the liquid pool is large. For this reason, the discharge amount of the droplet when the rod 8 descends next increases.

  FIG. 7 is a graph showing the change over time in the atmospheric pressure in the lower space of the piston 7 for two types with the supply pressure being large or small. By changing the supply pressure, the timing at which the piston 7 and the rod 8 begin to rise can be changed as shown in FIG. 7 (time T1, T2 in FIG. 7). However, when compared with the case of changing the flow rate in FIG. Further, if the supply pressure is further reduced in order to increase the timing difference, the pressure is close to the pressure required to raise the piston 7 and the rod 8, and the raising operation of the piston 7 and the rod 8 may become unstable. . From this point of view, as shown in FIG. 6, it is preferable to adjust the timing at which the piston 7 and the rod 8 start to rise by changing the flow rate while keeping the supply pressure constant.

  FIG. 8 is a flowchart of the discharge amount adjustment (correction) operation in the droplet applying apparatus according to the present embodiment. This operation is performed by a control device (discharge amount adjusting means) that executes a discharge amount adjusting program, and is started when, for example, application to a predetermined number of substrates is completed. First, a discharge amount correction method is selected (S1). Here, correction is performed by a different method depending on whether the viscosity of the liquid to be applied is “high”, “medium”, or “low”. The control device determines the viscosity of the liquid, for example, according to the type of the manually input liquid. Thereafter, the amount of shots is measured a predetermined number of times (S2). The discharge amount per one shot is regarded as a value obtained by dividing the amount in a predetermined number of shots by the number of times (eg, when measuring the amount after 100 shots, the amount obtained by dividing the measured amount by 100 is discharged in one shot. Is considered a quantity). Then, pass / fail determination is performed based on the difference between the measured amount and the target discharge amount (S3). As a result, when it is determined that the difference between the measured amount and the target discharge amount is within a predetermined value (OK in S3), the correction operation is terminated. On the other hand, if the difference between the measured amount and the target discharge amount exceeds a predetermined value and fails (NG in S3), it is confirmed whether the number of corrections in the current correction operation exceeds the specified number. (S4). If the number of corrections exceeds the specified number (Yes in S4), the user is notified by an alarm (light or sound) (S5), and the apparatus is stopped. If the number of corrections is within the specified number (No in S4), the correction is performed according to the correction method selected in S1. That is, when low viscosity is selected in the correction method selection (S1), a flow rate change command is issued (S6), the opening of the variable throttle valve 14 is adjusted, and the amount is measured again (S2). When the medium viscosity is selected in S1, it is confirmed whether or not the number of flow rate changes in the current correction operation exceeds the specified number (S7). If the number of flow rate changes is within the specified number (No in S7), a flow rate change command is issued (S8), the opening degree of the variable throttle valve 14 is adjusted, and the amount is measured again (S2). If the flow rate change count exceeds the prescribed count (Yes in S7), a stroke change command is issued (S9), the amount of protrusion of the variable stopper 19 is adjusted, and the amount is measured again (S2). If high viscosity is selected in S1, a stroke change command is issued (S10), the amount of protrusion of the variable stopper 19 is adjusted, and the amount is measured again (S2). The flow rate change or stroke change is repeated until it is accepted in pass / fail judgment (S3) or until the number of corrections in the current correction operation exceeds the specified number (S4). Then, when the discharge amount adjustment (correction) is completed and the preparation of the substrate to be applied next is completed, the application to the substrate is started.

  According to the present embodiment, the following effects can be achieved.

(1) When the application to a certain substrate (for example, a predetermined number of substrates) is completed, the discharge amount is adjusted, and when the adjustment is completed and the preparation of the substrate to be applied next is completed, the application to the substrate is started. The time for replacing the substrate to be coated can be used effectively, and the time loss due to the adjustment of the discharge amount can be reduced.

(2) The new discharge amount adjustment method of changing the rod set stroke shown in FIG. 3B is used, and the discharge amount can be appropriately adjusted even when the liquid to be coated has a high viscosity.

(3) When supplying compressed air to the space below the piston 7, a new discharge amount adjustment method is used in which the flow rate is changed while keeping the supply pressure constant, compared with the case where the supply pressure is changed. The timing at which the piston 7 and the rod 8 start to rise can be controlled flexibly and stably.

(4) The above two methods are properly used according to the viscosity of the liquid to be applied, and flexible discharge amount adjustment according to the liquid to be applied becomes possible.

  The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

  In the embodiment, the piston 7 is lowered by pressing the upper side of the piston 7 with a spring (single-acting type), but the piston 7 is lowered by pressurizing the space above the piston 7 (double-acting type). May be used.

  In the embodiment, the droplet amount is measured and compared with the target value when adjusting the ejection amount. However, instead of the amount, for example, the diameter of the droplet may be specified by image processing and compared with the target value.

  In the operation shown in FIG. 7, both the flow rate change (S8) and the stroke change (S9) may be performed after one pass / fail determination (NG in S3).

1 Syringe, 2 Liquid passage, 3 Liquid reservoir, 4 Nozzle, 5 Discharge port, 6 Cylinder, 7 Piston, 8 Rod, 9 Spring, 10, 11 Seal, 12 Intake port, 13 Exhaust port, 14 Variable throttle valve, 15 Switching valve, 16 intake / exhaust port, 17 variable speed controller, 18 stopper end, 19 variable stopper

Claims (5)

A liquid reservoir for storing the liquid to be applied;
A discharge path extending from the liquid reservoir and having a tip serving as a discharge port;
A rod whose tip reciprocates toward the discharge path in the liquid reservoir,
A piston provided on the base end side of the rod;
A cylinder containing the piston;
An urging means for urging the piston in a direction in which the rod faces the discharge path;
Piston driving means for reciprocating the piston by changing the air pressure of at least one of the spaces in the cylinder partitioned by the piston;
A discharge amount adjusting means for adjusting a discharge amount per one shot of droplets discharged from the discharge port;
A droplet applying apparatus that adjusts the discharge amount by the discharge amount adjusting means when application to a certain substrate is completed, and starts application to the substrate when the adjustment is completed and preparation of the substrate to be applied next is completed .   The droplet applying apparatus according to claim 1, wherein the discharge amount adjusting unit adjusts the discharge amount by changing a stroke of the piston.   The droplet applying apparatus according to claim 1, wherein the discharge amount adjusting unit adjusts the discharge amount by changing a flow rate of air when the piston is moved backward by the piston driving unit.   The discharge amount adjusting means adjusts the discharge amount by changing the stroke of the piston, and changes the flow rate of air when the piston is retracted by the piston driving means. The second discharge amount adjustment for adjusting the discharge amount can be performed, and it is determined which discharge amount adjustment is performed or both of the discharge amount adjustments are performed according to the viscosity of the liquid to be applied. The droplet applying apparatus according to claim 1.   The droplet coating apparatus according to claim 3 or 4, wherein a supply pressure when the flow rate is changed is constant.