JP6177291B2 - Droplet ejection apparatus and method - Google Patents

Description

  The present invention is a liquid that accurately discharges a liquid material ranging from a low-viscosity material such as water, a solvent, and a reagent to a high-viscosity material such as a solder paste, a silver paste, and an adhesive regardless of the filler content. The present invention relates to a droplet discharge apparatus and method.

Various techniques have heretofore been proposed for a droplet discharge device that discharges a small amount of liquid material from a discharge port using a reciprocating plunger.
As a droplet discharge device of a type that discharges with the tip of the plunger against the valve seat, for example, Patent Document 1 discloses an outlet connected to a nozzle as a droplet discharge device that causes a liquid material to land on a work after being separated from the nozzle. A side surface of the plunger is disposed in a non-contact manner in a flow path having a valve seat in the vicinity. The tip of the plunger moves toward the valve seat and comes into contact with the valve seat. An apparatus for discharging in the state is disclosed.

However, when the plunger is brought into contact with the valve seat, the plunger wears out and changes in shape, and wear powder and wear pieces are generated, contaminating the liquid material or being caught between the plunger and the valve seat. In other words, there was a problem of preventing good discharge.
Therefore, the applicant, as a droplet discharge device that discharges without touching the tip of the plunger to the valve seat, applies an inertial force to the liquid material by moving the plunger forward and stop, and discharges it into a droplet state. Proposed a droplet ejection device comprising a plunger position determining mechanism that regulates the position of the tip of the plunger when the advancement is stopped near the inner wall of the liquid chamber in the advancement direction ( Patent Document 2).

  Further, in Patent Document 3, a pressure wave formed by displacing the rod end surface back and forth with a very small stroke, high acceleration, and a large force in a room by a driving device is propagated through the material in the room. An apparatus for disposing a drop of fluid that ejects material from a nozzle opening is disclosed.

  By the way, in recent years, as electronic devices have been reduced in size and weight, electronic components mounted thereon have been reduced in size and weight. For example, a component having a mounting dimension of 400 μm × 200 μm called “0402 component” that can greatly reduce the mounting area has been mounted since around 2005. Currently, the 0402 component is mounted by solder printing using a metal plate, but there is a problem that it is necessary to devise half-etching when mixed with a large component. There is also a problem that individual control of the coating amount (coating thickness) is required. For this reason, the mounting by printing had a poor yield. Furthermore, in order to ensure printability, there are cases where restrictions are placed on the component arrangement.

  In the droplet discharge device using the reciprocating plunger, since the liquid material can be controlled by the operation of the plunger, these problems do not occur. However, in this type of device, a small amount of liquid such as solder paste required for small parts (for example, the landing diameter is several tens to several hundreds μm) and high accuracy without causing the plunger to contact the valve seat. No droplet discharge has been realized so far.

WO 98/10251 pamphlet International Publication No. 2008/108097 Pamphlet International Publication No. 98/16323 Pamphlet

  It is an object of the present invention to eject a minute amount of liquid droplets with high accuracy without causing the plunger to contact a liquid chamber wall (valve seat) in a liquid droplet ejection apparatus using a reciprocating plunger. .

  Further, it is a problem to be solved by the present invention to discharge various liquids ranging from low viscosity to high viscosity with the same droplet discharge device.

A first invention relating to a droplet discharge device includes a discharge path whose tip forms a discharge port, a plunger, a liquid chamber through which the plunger is inserted, a plunger drive mechanism for moving the plunger forward and backward, and a plan It has a plunger position determination mechanism that regulates the position of the tip of the jar, and the plunger moves forward from the operation start position while the outer periphery of the plunger and the side of the liquid chamber are not in contact with each other. In a droplet discharge device that applies force to discharge into a droplet state, the plunger moves forward while the tip of the plunger and the inner wall of the liquid chamber are not in contact with each other, thereby applying an inertial force to the liquid material. discharged state of the droplets, after dividing the liquid material extruded without being separated to the outside of the discharge port by the movement of the plunger outside of the discharge port, a liquid discharge opening neighborhood with the plunger moved backward Inhale the material A liquid-liquid interface is formed in the exit path, and the droplet is continuously moved back and forth so that air does not reach the liquid chamber, and the discharge operation is repeatedly performed as the operation start position. And
According to a second invention relating to the droplet discharge device, in the first invention described above, the discharge path communicates with the first flow path whose tip forms a discharge port, the first flow path and the liquid chamber, It consists of a second flow path having a diameter larger than one flow path, and is characterized in that a gas-liquid interface is formed in the first flow path or the second flow path of the discharge path .
A third invention according to the droplet ejection apparatus, in the invention described in the first or 2, the inner diameter of the discharge port, characterized in that several tens μm or less.
According to a fourth aspect of the present invention, a droplet discharge method includes a discharge path whose tip forms a discharge port, a plunger, a liquid chamber through which the plunger is inserted, a plunger drive mechanism for moving the plunger forward and backward, and a plunger The plunger is moved forward from the operation start position while the outer periphery of the plunger and the side surface of the liquid chamber are not in contact with each other by using a droplet discharge device having a plunger position determining mechanism for defining the position of the tip of the liquid In the droplet discharge method that applies an inertial force to the liquid material and discharges it into a droplet state, the plunger is moved forward while the tip of the plunger and the inner wall of the liquid chamber are not in contact with each other. After applying the inertial force to discharge into the state of droplets , the dividing step of dividing the liquid material pushed out without being divided outside the discharge port by the movement of the plunger outside the discharge port, after the dividing step, Plunger A suction step is performed in which the liquid material in the vicinity of the discharge port is sucked back to form a gas-liquid interface in the discharge path, and then the plunger is moved backward so that air does not reach the liquid chamber, thereby setting the operation start position. It is characterized in that droplets are continuously formed by repeating.

According to a fifth invention relating to a droplet discharge method, in the above-described fourth invention, the discharge path communicates with the first flow path, the first flow path and the liquid chamber, the tip of which forms the discharge port. The second flow path has a diameter larger than one flow path, and a gas-liquid interface is formed in the first flow path or the second flow path of the discharge path in the suction process .
Sixth invention according to the droplet ejection method, in the invention described in the fourth or fifth, a liquid material the liquid material containing solid matter, the plunger in the dividing step tip and the liquid chamber inner wall of the It is characterized in that the distance is set larger than that of the solid.
According to a seventh aspect of the droplet discharge method, in the invention according to any one of the fourth to sixth aspects, the forward movement distance of the plunger in the dividing step is that between the tip of the plunger and the liquid chamber immediately after the step. It is characterized by being larger than the distance of the inner wall.
An eighth invention according to the droplet discharge method is characterized in that in the invention described in any one of the fourth to seventh aspects, the inner diameter of the discharge port is several tens of μm or less.
According to a ninth aspect of the present invention, the liquid material has a viscosity of 10,000 mPa · s or more in the fourth to eighth aspects.

The present invention from another viewpoint is constituted by the following technical means.
The first invention includes a discharge path whose tip forms a discharge port, a plunger, a liquid chamber through which the plunger is inserted, a plunger drive mechanism for moving the plunger forward and backward, and the position of the tip of the plunger A plunger position determining mechanism that regulates the liquid material, and by moving the plunger forward in a state where the plunger tip and the inner wall of the liquid chamber are not in contact with each other, an inertial force is applied to the liquid material and discharged into a droplet state In the droplet discharge device, the amount of liquid material necessary to form a desired droplet is pushed out from the discharge port by moving the plunger forward, and then the plunger is moved backward from the discharge port. The extruded liquid material is divided to form a small amount of droplets, and the plunger is moved backwards to separate the liquid material pushed out from the discharge port, and then the plunger is further moved backwards. By moving to form an air-liquid interface in the discharge path, a droplet discharge apparatus characterized by stopping the movement of the plunger.
According to a second invention, in the first invention, the discharge path communicates with the first flow path whose tip forms a discharge port, the first flow path, and the liquid chamber, and has a larger diameter than the first flow path. It consists of two flow paths.
According to a third invention, in the second invention, after dividing the liquid material pushed out from the discharge port by moving the plunger backward, the plunger is further moved backward to move in the first flow path of the discharge path or A gas-liquid interface is formed in the second flow path, and the movement of the plunger is stopped.
According to a fourth invention, in any one of the first to third inventions, a gas-liquid interface is formed in the discharge passage, and the plunger is moved forward from the position of the plunger when the movement is stopped. The amount of liquid material required to form droplets is pushed out from the discharge port, and then the plunger is moved backward to break up the liquid material pushed out from the discharge port to continuously form a small amount of droplets. It is characterized by.
According to a fifth invention, in any one of the first to fourth inventions, an inner diameter of the discharge port is several tens of μm or less.

According to a sixth aspect of the present invention, there is provided a discharge path whose tip forms a discharge port, a plunger, a liquid chamber through which the plunger is inserted, a plunger drive mechanism for moving the plunger forward and backward, and the position of the tip of the plunger Using a droplet discharge device equipped with a plunger position determining mechanism that regulates the fluid, inertial force is applied to the liquid material by moving the plunger forward while the tip of the plunger and the inner wall of the liquid chamber are not in contact with each other. In the droplet discharge method for discharging into the state of droplets, the plunger is moved forward, the extrusion process that pushes out the amount of liquid material required to form the desired droplet from the discharge port, the plunger is retracted After the separation process, where the liquid material pushed out from the discharge port is divided to form a small amount of liquid droplets, and after the separation process, the plunger is further moved backward to form a gas-liquid interface in the discharge path. A droplet discharge method characterized by having a suction step of stopping the movement of the plunger.
According to a seventh invention, in the sixth invention, the discharge path communicates with the first flow path whose tip forms a discharge port, the first flow path and the liquid chamber, and has a diameter larger than that of the first flow path. It consists of two flow paths, and in the inhalation step, the plunger is moved backward to form a gas-liquid interface in the first flow path or the second flow path of the discharge path, and the movement of the plunger is stopped. To do.
According to an eighth aspect of the present invention, there is provided a discharge path whose tip forms a discharge port, a plunger, a liquid chamber through which the plunger is inserted, a plunger drive mechanism for moving the plunger forward and backward, and the position of the tip of the plunger Using a droplet discharge device equipped with a plunger position determining mechanism that regulates the fluid, inertial force is applied to the liquid material by moving the plunger forward while the tip of the plunger and the inner wall of the liquid chamber are not in contact with each other. In the droplet discharge method of discharging into a droplet state, the discharge path has a tip constituting a discharge port, communicates with the first channel having a smaller diameter than the plunger, the first channel and the liquid chamber, and at least the liquid The chamber side is composed of a second flow path having a diameter larger than that of the plunger, and an amount of liquid material required to form a desired droplet is moved from the discharge port by moving the plunger forward into the second flow path. Extrusion process, plunger A droplet discharge method characterized by having a dividing step to divide the liquid material extruded from the discharge port to form droplets of the trace by retracting move.
A ninth invention is the liquid material according to any one of the sixth to eighth inventions, wherein the liquid material contains a solid material, and the distance between the tip of the plunger and the inner wall of the liquid chamber in the extrusion process is greater than the solid material. It is characterized by a large setting.
A tenth invention is characterized in that, in any of the sixth to ninth inventions, the inner diameter of the discharge port is several tens of μm or less.
An eleventh invention is characterized in that in any of the sixth to tenth inventions, the liquid material has a viscosity of 10,000 mPa · s or more.
The twelfth invention is characterized in that, in any one of the sixth to eleventh inventions, the forward movement distance of the plunger in the extrusion process is larger than the distance between the tip of the plunger immediately after the process and the inner wall of the liquid chamber. And Here, the forward movement distance of the plunger in the extrusion process is preferably 3 times or more, more preferably 6 times or more of the distance between the tip of the plunger immediately after the process and the inner wall of the liquid chamber, More preferably, it is 10 times or more.

According to the present invention, it is possible to accurately discharge a minute amount of liquid droplets that could not be discharged without the plunger (valve element) contacting the liquid chamber wall (valve seat). .
Further, since the valve body and the valve seat do not come into contact with each other, there is no generation of rubbing pieces and particles, and there is no fear that they are mixed in the material, and it is possible to perform contamination-free minute discharge.
Moreover, even when the liquid material contains a solid material such as a filler, it is possible to prevent the deterioration of the discharge accuracy due to crushing or breakage of the solid material, and to discharge without impairing the function and properties of the liquid material. .

The side sectional view of the important section of a droplet discharge device for explaining the relation between the position of a plunger and the state of a liquid material. (A) is the first stage, (b) is the second stage, (c) is the third stage, (d) is the fourth stage, (e) is the fifth stage, and (f) is the second stage. Step 6, (g) shows the seventh step, and (h) shows the eighth step. The deformation | transformation structural example of the shape of a plunger and a discharge path. (A) is a first configuration example, (b) is a second configuration example, (c) is a third configuration example, (d) is a fourth configuration example, (e) is a fifth configuration example, (F) shows a sixth configuration example, (g) shows a seventh configuration example, and (h) shows an eighth configuration example. The side surface sectional view of a droplet discharge device provided with a plunger position determination mechanism. (A) shows a state where the moving member is advanced, and (b) shows a state where the moving member is retracted.

According to the present invention, the discharge of the tip of the discharge path formed in the advance direction of the plunger is caused by the advance / retreat movement of the plunger which is inserted into the insertion hole communicating with the liquid chamber and the tip moves forward and backward without contacting the inner wall of the liquid chamber. The present invention relates to a technique for discharging a liquid material from an outlet. By using the technique of the present invention, a liquid material ranging from low viscosity to high viscosity can be discharged in a liquid droplet state from a discharge port with a small amount with high accuracy regardless of the content of the filler.
According to the present invention, a small amount of liquid material from a low viscosity material such as water, a solvent, and a reagent to a high viscosity material such as a solder paste, a silver paste, and an adhesive can be discharged. The present invention is characterized in that it can be applied to a high-viscosity liquid that is not suitable for ink jet ejection, such as cream solder. Here, the high-viscosity liquid refers to a liquid having a viscosity of 10,000 to 500,000 mPa · s, for example. In particular, a liquid having a viscosity of 20000 mPa · s to 500,000 mPa · s, more specifically a liquid having a viscosity of 30000 mPa · s to 500000 mPa · s, is dropped without bringing the plunger (valve element) into contact with the liquid chamber wall (valve seat). Conventionally, discharging a minute amount in a state has not been realized at an industrial level.
The micro discharge in the present invention means, for example, discharge of a droplet having a landing diameter of several tens to several hundreds of μm or a droplet having a volume of 1 nl or less (preferably 0.1 to 0.5 nl or less). Say. The present invention is characterized in that droplets can be formed even with a discharge port diameter of several tens of μm or less (preferably 30 μm or less).

Below, an example of the form for implementing this invention based on FIG. 1 is demonstrated.
FIG. 1 is a cross-sectional view of a main part of a droplet discharge device (dispenser). First, the structure of the main part (ejection part) of the droplet ejection apparatus will be described.
The discharge unit illustrated in FIG. 1 includes a plunger 30, a liquid chamber 50, an insertion hole 51, a liquid feed path 52, and a discharge path 12.
The liquid chamber 50 is a space filled with a liquid material in which the distal end portion 31 of the plunger is located. The liquid chamber 50 illustrated in FIG. 1 has a top surface, a side surface, and a bottom surface, and is configured in a cylindrical shape.
An insertion hole 51 is provided on the upper surface of the liquid chamber 50. The plunger 30 is inserted into the insertion hole 51, and the tip of the plunger 30 is located in the liquid chamber 50. The width (diameter) of the liquid chamber 50 is wider than the width (diameter) of the plunger 30, and the outer periphery of the plunger 30 and the side surface of the liquid chamber 50 are always in a non-contact state. The plunger 30 is connected to a plunger drive mechanism (not shown), and moves linearly toward or away from the discharge path 12. In FIG. 1, the shape of the tip portion 31 is a plane, but the shape is not limited to this. For example, a spherical shape, a concave shape, a tapered shape, or a protrusion provided at a position facing the discharge path 12 is provided. Good. 2A to 2G show examples of the shape of the distal end portion 31 of the plunger.
A liquid feed path 52 is provided on the side surface of the liquid chamber 50. The liquid material is supplied to the liquid chamber 50 from a liquid material supply unit such as a liquid material storage container (not shown) through the liquid feed path 52.

A discharge path 12 communicating with the outside is provided on the bottom surface of the liquid chamber 50. The liquid material is discharged to the outside from the discharge port 11 at the tip of the discharge path 12 by the advance movement of the plunger. The inner diameter of the discharge port 11 is, for example, 10 to 100 μm. The shape of the discharge path 12 is not limited to a cylindrical shape, and may be a shape provided with a taper so as to be tapered (see FIGS. 2E and 2G). Moreover, you may comprise from the 1st flow path 21 which has a discharge outlet, and the 2nd flow path 22 larger diameter than a 1st flow path (refer FIG.2 (f)), and the 2nd flow path 22 is formed in this case It may be formed in a truncated cone shape (see FIGS. 2A to 2D). When the diameter of the liquid chamber side is larger than that of the discharge port side of the discharge path, there is an effect that the liquid material flowing into the discharge path is accelerated.
If the length of the discharge path is too long, the droplets may not be divided well, and this problem is likely to occur particularly in a liquid material having a high viscosity. For this reason, the discharge path 12 is preferably formed by an orifice provided with a hole in the wall surface 53 in the liquid chamber. The length of the discharge path is, for example, 100 μm to 1000 μm. Further, a recess having a diameter larger than that of the plunger 30 may be provided on the wall surface 53 in the liquid chamber, and a surface facing the distal end portion 31 of the plunger may be formed at a position closer to the discharge port. At this time, the discharge path 12 extends from the surface in the recess facing the tip 31 of the plunger to the discharge port 11 (see FIG. 2 (f)). The wall surface 53 may be a curved surface with a thin central portion where the discharge path 12 is located (see FIG. 2G).

  Examples of the plunger driving mechanism include a motor, a piezoelectric element, an elastic body such as a spring, and an actuator using air pressure. The plunger drive mechanism can adopt any means depending on the application. However, if you want to discharge various liquids ranging from low viscosity to high viscosity, you can adjust the plunger stroke within a certain range (other than piezo elements). Is preferably used. The plunger stroke when performing a small amount of discharge is, for example, 5 to 1000 μm. However, when discharging a highly viscous liquid, it is preferable to lengthen the stroke, for example, 50 to 1000 μm.

The position of the distal end portion of the plunger at the most advanced position is defined by the plunger position determining mechanism. In order to give sufficient inertial force to the liquid material in the advance direction of the plunger, the distance between the end surface of the plunger and the wall surface 53 of the liquid chamber facing the front end portion 31 of the plunger can be set sufficiently narrow. preferable. As the inner diameter of the discharge channel (nozzle) becomes smaller, the force exerted by the plunger on the liquid material needs to be increased. Accordingly, the distance (clearance) between the end surface of the plunger and the wall surface of the liquid chamber also needs to be reduced. is there.
For example, in order to form a droplet having a landing diameter of 300 μm or less with a high-viscosity liquid, the clearance is preferably set in the range of 1 to 50 μm, and more preferably set in the range of 1 to 30 μm. However, when the liquid material contains a solid material such as a filler, the most advanced position is set so that the clearance is larger than that of the solid material. For example, in the case of a cream solder having particles having an average particle diameter of 10 μm as the liquid material, the clearance needs to be larger than 10 μm (preferably the clearance is 1.5 times or more the size (particle diameter) of the solid substance. And). This is because the solder particles are crushed and stacked in the vicinity of the inlet of the discharge path, thereby causing a problem that the discharge accuracy is significantly lowered.

  The plunger position determining mechanism also defines the position of the distal end portion of the plunger at the most retracted position. When discharging a low-viscosity liquid material, the inertial force required to form droplets can be applied by moving the plunger at a certain speed, but when discharging a high-viscosity liquid material, the plan This is because it is necessary to set a longer stroke in order to move the jar at a higher speed. In general, when a very small amount of liquid having a high viscosity (for example, a liquid having a viscosity of 10,000 mPa · s or more) is discharged, the stroke needs to be set sufficiently larger than the clearance. The plunger stroke is preferably at least 3 times the clearance at the most advanced position, more preferably at least 6 times, and even more preferably at least 10 times.

An example of the plunger position determination mechanism will be described with reference to FIG. The plunger position determining mechanism described here is disclosed in Patent Document 2.
The determination of the most advanced position of the plunger is performed according to the following procedure.
First, the electromagnetic switching valve 72 is switched to a state where the front piston chamber 43 and the outside communicate with each other, and the moving member 40 is rotated so that the moving member 40 moves forward. Since the front piston chamber 43 is open to the outside, the piston 33 moves forward with respect to the main body 71 by the action of the coil spring 45, and the front contact portion 32 contacts the front stopper 41 and stops. Subsequently, the plunger 30 and the main body 71 are fixed by rotating the micrometer 69 to advance the rear stopper 42 and contacting the rear stopper 42.
The main body 71 is moved forward, and is fixed in a state where the rear stopper 42 and the rear contact portion 34 are in contact with each other. The distal end portion 31 of the plunger 30 is fixed at the contact position 13 where it contacts the inner wall of the liquid chamber 50. The moving member 40 is rotated, only the moving member 40 is moved backward to define the most advanced position, and the drive unit 70 is fixed to the base member 73.
With the above operation, the stop position when the plunger 30 is advanced can be adjusted to a desired position where the tip portion 31 of the plunger 30 does not contact the liquid chamber 50.

Determination of the last retracted position of the plunger is performed according to the following procedure.
The micrometer 46 is rotated to move the rear stopper 42 backward to determine the amount of movement of the plunger 30 during backward movement during discharge. When the amount of movement of the plunger 30 when retreating is determined, the micrometer 46 is fixed by a rotation lock member such as a fixing screw (not shown) so that the micrometer 46 does not rotate. With the above operation, the setting operation of the last retracted position of the plunger 30 is completed.

The droplet discharge device of the present invention is typically used in a mode of discharging a liquid material while relatively moving a workpiece and a discharge port. The droplet discharge device is attached to an XYZ drive mechanism and is moved relative to a work table on which a work is placed. In the present invention, since the liquid becomes droplets and is separated from the discharge port and landed on the work, the discharge port can be horizontally moved while being held at a constant height.
In some cases, one droplet is ejected to one work position, and in other cases, a desired amount is ensured by ejecting a plurality of droplets to the same location. Increasing the discharge amount per shot increases the landing diameter. Therefore, when it is not desired to increase the landing diameter, it is preferable to secure a desired amount by several shots. The droplet discharge device of the present invention can discharge a small amount of liquid continuously at a high speed, and can be operated at a high-speed tact of 100 shots or more per second, for example.

Next, the relationship between the position of the plunger and the state of the liquid material will be described.
FIG. 1A shows an initial state at the start of the discharge operation. In this initial state, the distal end portion 31 of the plunger 30 is in an operation start position that is located farthest from the discharge path 12 in a series of discharge operations. Further, the liquid chamber 50 and the discharge path 12 are in a state filled with the liquid material. At this time, the discharge port 11 side of the discharge path 12 may be in a state where a small amount of outside air (air) is sucked.

1B, the plunger is moved forward from the operation start position of the plunger in FIG. 1A, and the liquid material in the discharge passage 12 reaches the discharge port (the discharge port side end surface of the discharge passage 12). Indicates the state of the
At this time, the forward movement of the plunger 30 causes the liquid material in the liquid chamber 50 to be fed into the discharge path 12, and the liquid material in the discharge path 12 reaches the discharge port 11 at the tip of the discharge path 12. Thereby, the outside air (air) existing in the discharge passage 12 is discharged outside.

  FIG.1 (c) shows the state which moved the plunger further forward from the position of the plunger of FIG.1 (b). In this state, the liquid material that has reached the discharge port is pushed out without being divided to the outside of the discharge port.

FIG.1 (d) shows the state which stopped the advance movement of the plunger, after further moving the plunger further forward from the position of the plunger of FIG.1 (c).
At this time, the liquid material is pushed further outward from the discharge port 11 which is the tip of the discharge path 12 without being divided between the liquid chamber 50 and the leading edge.
In addition, it is preferable to perform forward movement of the plunger 30 so far vigorously and to stop the plunger 30 abruptly.

  In this state, the distal end portion 31 of the plunger 30 is at the most advanced position located closest to the discharge path 12 in a series of discharge operations. When the plunger 30 moves to the most advanced position, an amount of liquid material necessary to form a droplet of a desired size is pushed out of the discharge port 11. The most advanced position varies depending on the type of liquid material and the size of the droplet to be formed, but in any case, the distal end portion 31 of the plunger 30 does not contact the liquid chamber surface.

FIG.1 (e) shows the state which moved the plunger slightly backward from the position (most advanced position) of the plunger of FIG.1 (d).
When the plunger 30 moves backward, the ratio of the volume of the plunger that occupies the liquid chamber 50 decreases, and a force acts on the liquid material in the discharge passage 12 in the direction toward the liquid chamber 50. Along with this, the force of pulling back into the discharge path 12 also acts on the liquid material existing outside the discharge port 11 (the extruded liquid material connected to the liquid material in the discharge path 12). For this reason, an inertia force in the forward direction of the plunger acts on the liquid material pushed out from the discharge port, and a force in the backward direction of the plunger acts to start forming droplets. That is, the liquid material pushed out from the discharge port 11 connected to the liquid material in the discharge path 12 is subjected to a cutting action in the vicinity of the discharge port.

FIG. 1 (f) shows a state where the plunger is further moved backward from the position of the plunger shown in FIG. 1 (e).
When the plunger 30 is further moved backward, the cutting action on the liquid material pushed out from the discharge port 11 is further strengthened. Thereby, the liquid material pushed out from the discharge port 11 continuous from the discharge path 12 is divided at a portion in the vicinity of the discharge port to form droplets.
In FIG. 1 (f), both the vicinity of the dividing position of the liquid material on the side continuous from the discharge path 12 and the vicinity of the dividing position of the divided liquid material are depicted as thin threads. Generally, a high-viscosity material often has such a thread shape, but it also depends on the material properties and environmental conditions such as temperature and humidity. It does not indicate a thread-like aspect.

  FIG.1 (g) shows the state which moved the plunger further backward from the position of the plunger of FIG.1 (f). Of the liquid material pushed out from the discharge port 11, the liquid material remaining on the discharge path 12 side is sucked into the discharge path 12 by the backward movement of the plunger 30.

In preparation for the next discharge, preferably, the discharge port 11 side of the discharge path 12 is in a state of sucking a small amount of outside air (air). That is, it is preferable that a gas-liquid interface exists in the discharge path 12. By doing so, it is possible to prevent the liquid material from drying, and it is possible to prevent the surrounding environment from being contaminated by dripping when waiting for the discharge operation. Here, it should be noted that outside air (air) is not sucked into the liquid chamber 50 beyond the discharge path 12. This is because if the outside air (air) is sucked into the liquid chamber 50, the discharge accuracy is adversely affected.
In the case where the discharge path 12 includes the first flow path 21 and the second flow path 22, if the boundary between the first flow path 21 and the second flow path 22 does not form a step, the gas-liquid interface May be present in any of the first flow path 21, the second flow path 22 and their boundaries (for example, in the case of a flow path shape as shown in FIGS. 2A and 2B). In addition, as shown in FIG. 2 (f), even if the boundary between the first flow path 21 and the second flow path 22 constitutes a step, if no bubbles are formed, the second flow path 22. Can inhale outside air (air). Note that the boundary between the columnar first flow path 21 and the columnar second flow path 22 may be configured to be smoothly connected with a taper.

FIG. 1H shows a state where the plunger is further moved backward from the position of the plunger shown in FIG. FIGS. 1A to 1H show a series of operations for forming one drop. The position of the plunger at the end of one discharge is a position retracted from the most advanced position. In this state, a small amount of outside air (air) is sucked into the discharge port 11 side of the discharge path 12. Even if the outside air (air) is sucked into the discharge passage 12, the problem of bubbles does not occur as long as the air does not reach the liquid chamber 50. If the outside air flows into the liquid chamber 50, it causes a variation in the discharge amount, and it is necessary to avoid it. In order to continuously perform the next discharge operation, it is preferable to set the operation end position of the plunger as the operation start position.
When the discharge operation is completely completed, it is preferable to block the discharge path 12 with the tip 31 of the plunger 30 and prevent the liquid material from flowing out from the discharge port 11.

  Hereinafter, details of the present invention will be described by way of examples, but the present invention is not limited to the examples.

  Droplets were formed using the droplet discharge device shown in FIG. The liquid material used in Example 1 is a solder paste (viscosity 45000 mPa · s), and contains a filler having an average particle size of 6 μm. In this embodiment, the amount of one droplet discharged is 0.2 nl, and the landing diameter is 120 μm. Dozens of droplets are formed on the workpiece at a tact of 100 shots per second while the workpiece and the discharge port are moved relative to each other, and when measured with a measuring instrument, it is confirmed that dots having a uniform shape are formed. did it.

  Droplets were formed using the droplet discharge device shown in FIG. The liquid material used in Example 2 is an Ag paste (viscosity 28000 mPa · s) and contains 1 to 10 μm of flaky filler. In this embodiment, the amount of one droplet discharged is 0.17 nl, and the landing diameter is 100 μm. Dozens of droplets are formed on the workpiece at a tact of 250 shots per second while moving the workpiece and the discharge port relative to each other and measured with a measuring instrument to confirm that dots of uniform shape are formed. did it.

According to the present invention, it is possible to accurately discharge a material, which has been considered difficult in the electronic / semiconductor market, in a minute amount without bringing the plunger (valve element) into contact with the liquid chamber wall (valve seat). It becomes. For example, the paste material containing a soft metal material such as a solder paste can be continuously discharged without crushing and without clogging in the discharge device. The scope of application of the present invention is wide, such as a small component mounting process on a substrate and a solar cell manufacturing process.
In addition, since there is no contact between the valve body and the valve seat, there is no generation of rubbed particles or particles, and there is no fear of mixing them into the material (that is, contamination-free). Is preferred.

  In addition, since particles such as fillers, solids, gels, structures and the like are ejected and ejected without unnecessary destruction, nozzle clogging due to these destructions can be effectively prevented.

DESCRIPTION OF SYMBOLS 11 Discharge port 12 Discharge path 13 Contact position 21 1st flow path 22 2nd flow path 30 Plunger 31 Tip part 32 Front contact part 33 Piston 34 Back contact part 40 Moving member 41 Front stopper 42 Back stopper 43 Front piston chamber 44 Rear piston chamber 45 Coil spring 46 Micrometer 50 Liquid chamber 51 Insertion hole 52 Liquid feed path 53 Wall surface 71 of liquid chamber facing the plunger Main body 72 Electromagnetic switching valve 73 Base member 74 Discharge block

Claims (9)

Discharge path whose tip forms a discharge port, plunger, liquid chamber through which the plunger is inserted, plunger drive mechanism that moves the plunger forward and backward, and plunger position that defines the position of the tip of the plunger and a determination mechanism, and discharges to the state of the outer periphery and the liquid chamber the liquid droplets by applying inertial force side of the plunger at all times in a non-contact state to the liquid material by advancing movement from the working start position of the plunger liquid In the droplet ejection device,
Discharged in the state of droplets inner wall of the tip and the liquid chamber of the plunger is provided an inertial force to the liquid material by advancing movement of the plunger in a non-contact state,
After the liquid material pushed out without being divided to the outside of the discharge port by the movement of the plunger is divided outside the discharge port, the plunger is moved backward to suck the liquid material in the vicinity of the discharge port to discharge the liquid. A liquid-liquid interface is formed in the inside, and then the plunger is moved backward so that air does not reach the liquid chamber. Droplet discharge device.   The discharge path includes a first flow path whose tip forms a discharge port, a first flow path and a liquid chamber, and a second flow path having a larger diameter than the first flow path. The liquid droplet ejection apparatus according to claim 1, wherein a gas-liquid interface is formed in the path or the second flow path. The inner diameter of the discharge port, the liquid droplet ejection apparatus according to claim 1 or 2, characterized in that several tens of μm or less. Discharge path whose tip forms a discharge port, plunger, liquid chamber through which the plunger is inserted, plunger drive mechanism that moves the plunger forward and backward, and plunger position that defines the position of the tip of the plunger using the droplet ejection apparatus Ru and a determination mechanism, giving an inertial force to the liquid material by advancing movement side of the outer peripheral and the liquid chamber of the plunger always in a non-contact state of the plunger from the operation start position In a droplet discharge method for discharging into a droplet state ,
Discharged in the state of droplets inner wall of the tip and the liquid chamber of the plunger is provided an inertial force to the liquid material by advancing movement of the plunger in a non-contact state,
A cutting process in which the liquid material pushed out without being cut out of the discharge port by the movement of the plunger is cut outside the discharge port;
After the dividing step, the plunger is moved backward to suck the liquid material near the discharge port to form a gas-liquid interface in the discharge path, and then the plunger is moved backward so that air does not reach the liquid chamber. A droplet discharge method , wherein droplets are continuously formed by repeatedly performing a suction step at an operation start position . The discharge path is composed of a first flow path whose tip forms a discharge port, a first flow path and a liquid chamber, and a second flow path having a larger diameter than the first flow path.
5. The droplet discharge method according to claim 4 , wherein, in the suction step, a gas-liquid interface is formed in the first flow path or the second flow path of the discharge path. The liquid material according to claim 4 or 5 , wherein the liquid material is a liquid material containing a solid material, and the distance between the tip of the plunger and the inner wall of the liquid chamber in the dividing step is set larger than that of the solid material. Drop ejection method. 7. The droplet discharge method according to claim 4 , wherein the forward movement distance of the plunger in the dividing step is larger than the distance between the tip of the plunger immediately after the step and the inner wall of the liquid chamber. . The inner diameter of the discharge port, the liquid droplet ejecting method according to any one of claims 4 to 7, characterized in that several tens μm or less. The droplet discharging method according to any one of claims 4 to 8 fluid material is characterized in that a viscosity 10000 mPa · s or more.