JP2005076492A - Indirect fluid type diaphragm pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel diaphragm pump having improved discharging performance for high coating accuracy. <P>SOLUTION: The diaphragm pump for feeding fluid with high accuracy comprises a diaphragm mounting housing 24 storing the fluid to be fed and having a fluid outlet 11, a vent hole 12 and a fluid inlet 10 and internally shaped into a streamline for preventing the residence of the fluid, a diaphragm membrane 5 arranged in the housing 24 for separating the fed fluid 6 from driving indirect fluid 7 in a sealed condition and controlling the feed of the fed fluid in the housing with a change in the shape, an indirect fluid storage cylinder 4 for storing the indirect fluid for deforming the diaphragm membrane, an indirect fluid moving piston 3 for moving the indirect fluid in the indirect fluid cylinder, and a linear motor 1 having a motor driving shaft connected to the indirect fluid moving piston for driving the linear reciprocation of the piston and controlling it. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a novel diaphragm pump capable of dealing with fields requiring high discharge accuracy such as related coating apparatuses such as semiconductors, liquid crystals, plasma display panels (PDP), etc. The present invention relates to a fluid diaphragm pump.

  In recent years, with regard to wet coating methods such as photosensitive resin for films in the semiconductor and liquid crystal related fields, or glass substrates, it has been possible to save coating liquid (saving coating liquid), improve film thickness uniformity, improve chromaticity uniformity, etc. From the viewpoint, many slit coating methods have been proposed.

  Unlike the slot-and-spin coating method, the slit coating method is a method in which a desired film thickness is applied only by the slit, and compared with the coating at the slot stage by slot-and-spin, it is highly accurate. Application is required. As the high-precision coating means, the elements are divided in the coating direction and the coating width direction, and regarding the coating direction, a) conveyance of the substrate for coating or improvement of the feeding accuracy of the slot die, and b) discharge accuracy of the coating liquid dispensing apparatus. Improvement is known to be important.

  For high precision dispensing, semiconductor, liquid crystal, and plasma display panel (PDP) related coating devices require thin and uniform coating. In particular, as a means to achieve uniform coating, the coating liquid is uniformly ejected over time. It is important to.

  If the substrate transfer or slot die feed speed is ideally constant, the discharge uniformity of the discharge dispense device, that is, the linearity becomes the final film thickness uniformity. A linearity equivalent to the required specifications is required.

  There are a pressurization method and a pump method using a high-precision regulator in the coating liquid dispensing apparatus, and a pump method is advantageous for controlling an unstable portion at the start and end of application. In particular, the diaphragm pump can be completely isolated from the process. In other words, the final fluid and the device drive system are completely separated from each other by the diaphragm membrane. Therefore, it is highly useful in processes that require cleanliness, and high accuracy is achieved if the diaphragm membrane is driven indirectly. Discharge is possible.

  However, with regard to the uniform discharge performance of the diaphragm pump, that is, the linearity, it is not easy to satisfy sufficient performance depending on the accuracy and assembly accuracy of each element of the drive unit. In a conventional diaphragm pump drive system using a rotation mechanism such as a servo motor or a ball screw, the rotation of the motor and the wobbling of the ball screw cause a ripple (fluctuation) in the piston head speed that reciprocates the diaphragm membrane of the diaphragm pump. In other words, it is a major factor in reducing the discharge linearity. Here, the rotation unevenness of the servo motor is limited to about ± 1%, but the velocity ripple of the piston head shows about ± 8% in an experimental value.

  Further, a diaphragm pump using a conventional rotating mechanism as a drive source has periodic specific undulations. The speed ripple value of the piston head is the same as the undulation of the discharge flow rate, and in order to obtain the required coating film thickness accuracy, it is necessary to keep the piston speed ripple value to the same level. Because of the large number of parts, depending on the assembling accuracy, the feeding accuracy deteriorates.

In addition, discontinuous disturbance elements such as stick-slip may occur in the sliding part of the piston and cylinder due to the vibration of the posture of the piston. Such vibration of the posture causes uniform and continuous movement of the indirect fluid. Hinder. Further, in the conventional method, the posture accuracy of the piston may be deteriorated due to the offset of the ball screw shaft and the piston shaft and the low rigidity of the piston guide.

  Regarding factors that deteriorate the speed ripple of the piston head, a) parts downstream from the servo motor, that is, coupling, reduction gear, ball screw, piston mounting accuracy, b) speed reduction speed variation, c) coupling Rigidity and elasticity, d) staggering and rigidity of the ball screw, e) rigidity of the guide part, f) stick-slip of the guide part, g) and other disturbance elements having swell and discontinuity. The above factors cause deterioration of the coating film thickness accuracy.

  In recent years, high responsiveness and reproducibility of discharge pumps are required due to shortened tact time, that is, higher application speed. Therefore, in order to realize the high responsiveness of the discharge pump, it is indispensable to increase the response of the drive device, improve the rigidity, and reduce the weight. In order to increase the response, an incompressible fluid is used as the indirect fluid for driving. However, the use of the non-compressed fluid makes the drive shaft feed rate uniformity level prominent in the process, necessitating further improvement of drive shaft feed uniformity.

The linearity of the liquid feed is directly related to the feed uniformity of the diaphragm film, and indirectly related to the feed accuracy of the drive system that moves the indirect fluid. That is, theoretically, the feed accuracy required for the drive system is equivalent to the spec value of the final desired process. In processes related to semiconductors, liquid crystals, and PDPs, discharge accuracy (linearity) of a discharge pump of at least ± 5% or less is required.
JP 54-52304 A JP-A-5-304754 Japanese Patent Laid-Open No. 6-22529

  From the above problems, the problem to be solved by the present invention is to provide a novel diaphragm pump for obtaining a high coating accuracy in which the discharge performance of the diaphragm pump in the prior art is further improved.

The invention according to claim 1 of the present invention is a diaphragm pump for feeding a fluid with high accuracy, and a) contains a fluid to be fed, has a fluid outlet, a fluid inlet, and a vent adjustment port, and has an internal shape. A diaphragm mounting housing that accommodates the indirect fluid for driving and the fluid to be fed having fluid retention prevention and streamlined shape;
b) A diaphragm membrane which is arranged in a diaphragm mounting housing, divides the liquid to be fed and the indirect fluid for driving into a sealed state, and controls liquid feeding in the housing by shape change;
c) an indirect fluid containing cylinder for containing an indirect fluid for deforming the diaphragm membrane;
d) an indirect fluid moving piston for moving the indirect fluid in the indirect fluid cylinder;
e) a linear motor that is connected to a piston for indirect fluid movement and includes a motor drive shaft that linearly drives and controls the piston in a reciprocating manner;
An indirect fluid diaphragm pump characterized by comprising:

  According to a second aspect of the present invention, in the indirect fluid diaphragm pump according to the first aspect, a linear reciprocating drive speed ripple (fluctuation) of the piston by the motor drive shaft of the linear motor is ± 5%. This is an indirect fluid diaphragm pump characterized by being capable of liquid feeding with high linearity.

  The invention according to claim 3 of the present invention is the indirect fluid type diaphragm pump according to claim 1 or 2, wherein the linear motor is a direct-acting shaft type linear motor, and the motor drive shaft of the linear motor An air slide guide mechanism that linearly guides the motor, and the linear guide direction by the air slide guide mechanism and the linear reciprocation direction of the piston connected to the motor drive shaft are arranged on the same straight line. It is an indirect fluid type diaphragm pump characterized by these.

  The invention according to claim 4 of the present invention is the indirect fluid type diaphragm pump according to claim 3, wherein the air slide guide mechanism has a highly rigid air slide guide. .

  The invention according to claim 5 of the present invention is the indirect fluid diaphragm pump according to any one of claims 1 to 4, wherein the linear reciprocating drive direction of the motor drive shaft of the linear motor is horizontal. An indirect fluid diaphragm pump characterized by being installed as described above.

  The invention according to claim 6 of the present invention is the indirect fluid diaphragm pump according to any one of claims 1 to 5, wherein the shape of the diaphragm film is a stepped or rounded shape, and the diaphragm The indirect fluid diaphragm pump is characterized in that the amount of thrust used for the linear motor is suppressed by suppressing the generation of the tension of the membrane.

  The invention according to claim 7 of the present invention is the indirect fluid type diaphragm pump according to any one of claims 1 to 6, wherein the vent adjustment port is normally in a closed state and pumps liquid as necessary. The indirect-fluid diaphragm pump according to any one of claims 1 to 6, wherein the indirect-fluid diaphragm pump is a fluid outlet of the power fluid.

  According to the indirect fluid type diaphragm pump of the present invention, the housing for receiving the liquid to be fed, the diaphragm film for controlling the liquid feeding by isolating the indirect fluid for driving to drive the diaphragm film and the liquid to be fed, for driving Cylinder (pump chamber) that constitutes an indirect fluid housing, a piston that moves the indirect fluid for driving in the cylinder, and a linear motor that is a driving source of the piston, and a diaphragm for feeding fluid with high accuracy Provided as a pump.

  The diaphragm membrane isolates the indirect fluid for driving that drives the diaphragm membrane from the fluid to be delivered, maintains the cleanliness of the process, and deformation of the diaphragm membrane allows the membrane membrane in the housing that contains the fluid to be delivered to be accommodated. Dispense and feed liquid feeding fluid.

  By using an incompressible fluid as the driving indirect fluid in the present invention, high responsiveness and reproducibility can be realized. However, since the level of feed uniformity related to the movement of the indirect fluid appears remarkably by using an incompressible fluid, the drive system in the present invention includes means that considers improvement in uniformity. The means is that the feed accuracy of the pump drive system including the piston that moves the indirect fluid for driving in the cylinder and the linear motor that is the drive source thereof is about ± 5% or less. Is that a linear motion of a linear motor is used without providing a conventional rotating mechanism.

  The linear motor drive system requires fewer parts than a drive system using a rotation mechanism, and has an advantage over a rotation mechanism that generates unique rotation unevenness and feed unevenness such as motors, reducers, and ball screws. is there.

  As a means for improving the deterioration of piston feed uniformity accuracy of the drive system due to the deterioration of the assembly accuracy of the conventional discharge pump speed reducer, ball screw, and guide, in the present invention, the guide for reciprocating movement of the piston by driving the linear motor is used. By using an air slide guide mechanism (air slider), the assembly accuracy of the drive system can be improved. That is, the assembly accuracy can be improved and the linear motor driving performance can be sufficiently exhibited. Further, by using the air slide guide mechanism, the sliding resistance of the guide mechanism can be reduced. Regarding the rigidity of the air slider, the pressure of the indirect fluid for driving, that is, the thrust of the piston, can be improved by setting the rigidity to suppress the cogging and posture fluctuation to ± 2% or less. The offset amount between the power point and the action point can be suppressed, and the deflection of the posture of the piston can be suppressed.

  Since the deflection of the posture of the piston by the air slider is increased by the offset amount between the force point and the action point, the motor drive shaft and the piston shaft of the linear motor are aligned in a straight line as means for preventing the piston posture from being shaken. By arranging and connecting as in-line, the offset can be reduced.

  The linear motor can remarkably increase the speed ripple (fluctuation) due to heat generation, which can cause a decrease in discharge accuracy (linearity). As a means to suppress the heat generation of the linear motor, in the present invention, by installing the linear motor horizontally, the gain and current consumption when stopping due to gravity can be minimized, and not only when stopping but also during operation In addition, the influence of inertia of the motor drive shaft of the linear motor can be reduced, and the gain can be minimized.

  In order to suppress the power consumption of the linear motor, it is important to reduce the reaction force (necessary thrust) applied to the linear motor. As a means for reducing the reaction force, in the present invention, the shape of the diaphragm film is changed to the curvature. By using the R shape or the stepped shape, it is possible to suppress the thrust consumption related to the linear motor that is lost due to the tension of the diaphragm film.

  As described above, the diaphragm pump of the present invention can be improved with high accuracy with a discharge accuracy of ± 5% or less, and an accuracy that satisfies high-precision discharge performance related to semiconductors, liquid crystals, and PDPs can be obtained. In addition, the periodic undulation inherent in diaphragm pumps using a conventional rotating mechanism as a drive source is eliminated, and the gain can be minimized by installing the linear motor drive direction horizontally. This has the effect of contributing to improved speed, improved responsiveness, space saving and reduced power consumption.

  The indirect fluid diaphragm pump according to the present invention will be described in detail below with reference to the plan view of FIG. 1. A linear motor 1 and a motor drive shaft 1a of the linear motor 1 are linearly connected to the pump body frame F. An air slide guide mechanism 2 (linear guide by an air slider, 2a is an air press-fit / discharge pipe for providing an air slide function (air slider)) is provided, and the guide mechanism 2 is a pump body frame. It is fixedly attached at a fixed position of F.

The structure of the linear motor 1 is not particularly limited in the present invention. For example, the linear motor 1 has a motor drive shaft 1a that can slide in the air slide guide mechanism 2, and the motor drive shaft 1a has one or several slides whose longitudinal direction is the sliding movement direction. Linear slide shafts 1b, 1c and 1c, each of which has a slide shaft 1b,
1c and 1c are fitted and loaded in a coil hole 22 in which a three-phase armature coil C for propulsion of the coil holding frame 21 attached to the pump body frame F is mounted on the inner peripheral surface.

  On the outer peripheral surface of each slide shaft 1b, 1c, 1c, superconducting magnets in which N-pole and S-pole magnets are alternately arranged along the longitudinal direction are arranged, and the three arranged in a range corresponding to two poles. The slide shafts 1b, 1c, 1c move by two poles for each cycle of the alternating current input to the phase armature coil C, and move forward and backward by reversing the 180 ° phase difference of the input alternating current. The motor drive shaft 1a of the linear motor 1 is linearly reciprocally slidably moved in the air slide guide mechanism 2 by the forward and backward movements of the slide shafts 1b, 1c, and 1c.

  A piston 3 whose linear stroke direction is the same direction as the reciprocating sliding movement stroke direction is coupled to the motor drive shaft 1a of the linear motor 1 in a fixed state via a bracket portion 3a. The indirect fluid 7 (for example, a liquid such as water or hydraulic oil) is fitted into the piston cylinder 4 so as to be reciprocally slidable.

  On the opposite side of the pump body frame F from the linear motor 1, there is an internal space shape composed of an indirect fluid housing wall 23 for receiving the liquid to be fed 6 and the driving indirect fluid 7 and a housing wall 25 for the liquid to be fed. A diaphragm mounting housing 24 having a fluid retention prevention and streamline shape is attached, and the piston cylinder 4 is attached to the indirect fluid housing wall 23 side so as to pass through each other, and the piston cylinder 4 and the diaphragm The inside of the mounting housing 24 communicates with each other as a sealed space.

  An inlet 10 through which the liquid to be fed 6 flows into the diaphragm mounting housing 24 and a liquid to be fed from the inside of the mounting housing 24 enter the liquid feeding fluid housing wall 25 opposite to the piston cylinder 4 of the diaphragm mounting housing 24. Provided with an outlet 11 (discharge port) through which the fluid 6 (for example, photosensitive resin liquid, resin coating solution, etc.) flows out, and a vent adjustment port 12 (normally closed air vent for adjustment) as required. ing.

  Inside the diaphragm mounting housing 24, the indirect driving fluid 7 in the piston cylinder 4 and the liquid supply fluid 6 flowing in from the inlet 11 of the liquid supply housing wall 25 are divided into a sealed state. The thin film sheet-like diaphragm membrane 5 to be isolated is sealed at the outer peripheral end portion of the membrane at the overlapping portion of the peripheral end portion of the indirect fluid housing wall 23 and the liquid feed housing wall 25 constituting the housing 24. It is held by and attached. The space shape inside the housing 24 is suitably a shape that takes into consideration the prevention of fluid retention and streamlines so as not to hinder the inflow performance and discharge performance of the fluids 6 and 7. The planar shape of the diaphragm film 5 used in the present invention can be set as appropriate, such as a circular shape, an elliptical shape, a quadrangular shape, or a polygonal shape, and is not particularly limited.

  The discharge principle of the diaphragm pump is that the diaphragm film 5 that separates the liquid 6 to be fed and the indirect fluid 7 for driving is deformed in one cycle forward and backward in the indirect fluid housing 24 by the movement of the indirect fluid 7 for driving. Alternatively, the fluid to be fed 6 is pushed out from the inside of the housing 24 to the outflow port 10 or flows into the inside of the housing 24 from the inflow port 11 by repeated deformation operation of two or more cycles. Note that it is appropriate to use an incompressible fluid for the driving indirect fluid 7, and water glycol, phosphate ester or the like is desirable.

The driving indirect fluid 7 accommodated in the piston cylinder 4 is moved to the vicinity of the diaphragm film 5 by the forward movement of the piston 3 in the direction of the diaphragm film 5. As a result, the diaphragm film 5 is moved to the liquid fluid 6 to be fed. The piston 3 is moved in the direction away from the vicinity of the diaphragm film 5 by retreating in the direction away from the direction of the diaphragm film 5, and as a result, the diaphragm film 5 is moved into the liquid fluid 6 to be fed. It is deformed in the direction of inflow.

  In this way, the deformation operation of the diaphragm film 5 is controlled by the piston operation, and the liquid to be fed 6 is isolated from the driving indirect fluid 7 by the diaphragm film 5, so that the pumping process (fluid system) and the pumping drive system are It becomes possible to perform a pumping operation in a state in which and are isolated.

  As described above, the piston 3 is driven and controlled by the linear motor 1. With respect to the linear motor employed in the present invention, the linear motor is selected by obtaining the required propulsive force from the multiplication of the design value of the discharge pressure of the liquid to be fed 6 and the bore area of the piston. Taking into account the deterioration of the speed ripple (fluctuation) of the piston head due to the generation of frictional heat between the piston 3 and the cylinder 4, it is possible to take measures such as doubling the safety factor of the actual use range driving force.

  The linear motor 1 has a structure in which the motor coil portion C and the air slide guide mechanism 2 (air slider guide) are installed in series to improve the posture accuracy of the piston 3. When the motor coil part C and the guide mechanism 2 are in series, both axes are in-line, and it is possible to suppress the generation of moments and improve posture accuracy. The linear motor 1 has a speed ripple of ± 0.1 to ± 5% when used alone or without load. As a standard for the adoption, a spec obtained by estimating a safety factor from a desired discharge accuracy can be used.

  Further, regarding the guide of the motor drive shaft 1a of the linear motor 1, by adopting an air slide guide mechanism 2 (air slider) for the purpose of improving posture accuracy and suppressing sliding resistance, improving posture accuracy and sliding resistance. It is effective to improve positioning accuracy and speed ripple. However, it is appropriate that the distance between the guide portions of the air slider has rigidity in consideration of the deflection of the posture depending on the magnitude of the propulsive force and the offset amount of the reaction force from the piston head.

  In the diaphragm pump of the present invention, the linear motor 1 is placed in a no-load state when the pump is stopped by being installed so that the driving direction of the linear motor 1 is horizontal. Therefore, the current consumption of the linear motor 1 is suppressed to a minimum except during discharging. Moreover, since the weight of the motor drive shaft 1a (motor head) of the linear motor 1 does not affect the load of the linear motor itself by the horizontal installation, the inertia can be reduced. As a result, when the linear motor 1 is installed vertically, the positioning accuracy is ± 1 μm or less and the speed ripple is ± 1% or less. However, when the linear motor 1 is installed horizontally, the positioning accuracy is ± 0.4 μm or less and the speed ripple. ± 3% or less can be achieved.

The top view of the diaphragm pump of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Linear motor 2 ... Air slide guide mechanism 3 ... Piston
DESCRIPTION OF SYMBOLS 4 ... Piston cylinder 5 ... Diaphragm film | membrane 6 ... Liquid to be sent 7 ... Indirect fluid 23 for a drive ... Housing wall for indirect fluid 24 ... Diaphragm mounting housing 25 ... Housing wall for liquid to be fed

Claims (7)

A diaphragm pump for feeding fluid with high accuracy,
a) Accommodates fluid to be sent, has fluid outlet, fluid inlet, vent adjustment port, and contains indirect fluid for driving and fluid to be fed with internal shape of fluid retention prevention and streamlined shape A diaphragm mounting housing,
b) A diaphragm membrane which is arranged in a diaphragm mounting housing, divides the liquid to be fed and the indirect fluid for driving into a sealed state, and controls liquid feeding in the housing by shape change;
c) an indirect fluid containing cylinder for containing an indirect fluid for deforming the diaphragm membrane;
d) an indirect fluid moving piston for moving the indirect fluid in the indirect fluid cylinder;
e) a linear motor that is connected to a piston for indirect fluid movement and includes a motor drive shaft that linearly drives and controls the piston in a reciprocating manner;
An indirect fluid diaphragm pump characterized by comprising:   2. The linear reciprocating drive speed ripple (fluctuation) of the piston by the motor drive shaft of the linear motor is ± 5% or less, and liquid feeding with high linearity is possible. Indirect fluid diaphragm pump.   The linear motor is a linear shaft type linear motor, and includes an air slide guide mechanism that linearly guides a motor drive shaft of the linear motor, and a linear guide direction by the air slide guide mechanism, and the motor 3. The indirect fluid diaphragm pump according to claim 1, wherein a linear reciprocating direction of a piston connected to the drive shaft is arranged on the same straight line.   The indirect fluid diaphragm pump according to claim 3, wherein the air slide guide mechanism includes a highly rigid air slide guide.   5. The indirect fluid diaphragm pump according to claim 1, wherein the linear reciprocating drive direction of the motor drive shaft of the linear motor is horizontal. 6.   The shape of the diaphragm film is a stepped or rounded shape, and the amount of thrust used by the linear motor is suppressed by suppressing the generation of tension in the diaphragm film. The indirect fluid diaphragm pump according to any one of the above.   The indirect fluid diaphragm pump according to any one of claims 1 to 6, wherein the vent adjustment port is normally in a closed state, and serves as a fluid outlet of a fluid to be fed as necessary.