JP2002102766A - Coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating device capable of the high speed discharge cutting and the high precision flow controlling of various powder fluids such as of an adhesive, a clean solder, a fluorescent body, grease, coating materials, hotmelt, chemicals or foods without compressing or breaking powder in an industrial process in a field of electronic parts, household electric appliances, or the like. SOLUTION: In a small flow pump performing a combination of linear motion and rotary motion, a screw pump is formed by using the rotary motion and the displacement in the axial direction is controlled by penetrating its center shaft through the inside of the rotary shaft of the flow pump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention discharges various liquids such as adhesives, cream solders, phosphors, greases, paints, hot melts, chemicals, foods, etc. in a production process in the fields of electronic parts, home electric appliances and the like. The present invention relates to a fluid discharge device and a discharge method for discharging or for uniformly applying a phosphor on a display surface such as a CRT or PDP.

[0002]

2. Description of the Related Art Liquid ejecting apparatuses (dispensers) have been used in various fields, but with the recent demand for miniaturization and high recording density of electronic components, a minute amount of fluid material can be dispensed with high precision. There is a demand for a technique for stably controlling discharge.

[0003] Taking the field of surface mounting (SMT) as an example,
In the trend of high-speed mounting, miniaturization, high-density, high-quality, and unmanned mounting, the problems of dispensers can be summarized as follows: high-precision coating amount and miniaturization of one-time application amount. It can be used for high viscosity powder fluids. Conventionally, a dispenser of an air pulse type, a screw groove type, a micropump type using an electromagnetic strain element, or the like has been put to practical use in order to discharge a very small amount of liquid.

[0004]

Among the prior art examples described above, a dispenser using an air pulse method as shown in FIG. 9 is widely used.
The technology is introduced in “3.25, Issue 7” and the like. In this type of dispenser, a fixed amount of air supplied from a constant pressure source is applied in a pulsed manner into a container 300 (cylinder), and a fixed amount of liquid corresponding to a rise in the pressure in the cylinder 300 is discharged from a nozzle 301. Things.

[0005] The air pulse type dispenser has a drawback that response is poor.

[0006] This disadvantage is due to the compressibility of the air 302 enclosed in the cylinder and the nozzle resistance when passing the air pulse through a narrow gap. That is, in the case of the air pulse method, the cylinder volume: C and the nozzle resistance: R
The time constant of the fluid circuit that can be achieved: T = RC is large, and after the input pulse is applied, a time delay of, for example, about 0.07 to 0.1 seconds from the start of ejection must be expected.

In order to eliminate the drawbacks of the air pulse method, a needle valve is provided at the inlet of the discharge nozzle.
A dispenser that opens and closes a discharge port by moving a small-diameter spool constituting the needle valve at high speed in an axial direction has been put to practical use.

However, in this case, when the fluid is shut off, the gap between the relatively moving members becomes zero, and the powder having an average particle diameter of several to several tens of microns is mechanically pressed and destroyed. Due to various inconveniences that occur as a result, it is often difficult to apply the method to application of an adhesive material, a conductive paste, or a phosphor mixed with powder.

For the same purpose, a screw-type dispenser which is a viscous pump has already been put to practical use. In the case of the thread groove type, a pump characteristic that is hardly dependent on the nozzle resistance can be selected, so that a preferable result can be obtained in the case of continuous spraying. However, the intermittent application is not good in the nature of the viscous pump. Therefore, in the conventional screw groove type, (1) an electromagnetic clutch is interposed between the motor and the pump shaft, and this electromagnetic clutch is connected or released when the discharge is turned ON or OFF.

(2) Use a DC servomotor to start or stop rapid rotation.

However, since the response is determined by the time constant of the mechanical system in any of the above cases, the high-speed intermittent operation is limited. The responsiveness is better than that of the air pulse method, but the shortest time is about 0.05 seconds.

In addition, since there are many uncertain factors in the rotation characteristics of the pump shaft during transient response (at the start and stop of rotation), it is difficult to strictly control the flow rate and the coating accuracy is limited.

For the purpose of discharging a very small amount of fluid, a micropump using a laminated piezoelectric element has been developed. For this micro pump, a mechanical passive discharge valve or suction valve is usually used.

However, in the above-described pump which is constituted by a spring and a ball and opens and closes a discharge valve and a suction valve by a pressure difference,
It is extremely difficult to intermittently discharge a high-viscosity rheological fluid of tens of thousands to hundreds of thousands of centipoise with poor flowability at high flow rate accuracy and at high speed (0.1 seconds or less).

Now, in the field of circuit formation, which is becoming increasingly more precise and ultra-fine in recent years, or in the fields of forming electrodes and ribs for picture tubes such as PDPs and CRTs, applying sealing materials for liquid crystal panels, and manufacturing processes for optical discs and the like. There are strong demands for fine coating technology as follows.

After continuous spraying, the application is stopped immediately. The time of the discharge cutoff is as short as possible, and ideally, the discharge cutoff can be performed, for example, on the order of 0.01 second. In the case of discharge start, so-called "discarding" can be performed at another location. However, in the case of discharge cut-off, this method cannot be used.

Able to handle powder fluid. For example, there should be no troubles such as powder compression breakage or flow path clogging due to mechanical cutoff of the flow path.

The present invention is a further improvement of the above-mentioned proposal. In a minute flow rate pump composed of a combination of a linear motion and a rotary motion, a thread groove pump is constituted by using a rotary motion, and a center shaft is provided inside a rotary shaft. To control the displacement in the axial direction, thereby increasing the speed and accuracy of the discharge amount control.

[0019]

According to the present invention, there is provided a fluid discharging apparatus comprising: a center shaft provided through the inside of a sleeve; a first actuator for relatively linearly driving the center shaft and the sleeve; A housing for storing the
A fluid suction hole and a discharge hole formed in the housing, a second actuator for providing relative rotational movement between the sleeve and the housing, and a suction hole formed between the sleeve and the housing; In a coating apparatus including a fluid transport chamber communicating with a discharge port and a unit for pressure-feeding a fluid in the fluid transport chamber, an axial movement of the central axis causes a displacement between a discharge-side end of the central axis and the housing. The discharge flow rate is adjusted by changing the volume or flow path resistance formed in the nozzle.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is used to speed up the discharge amount control will be described below. That is, in the present embodiment, the volume of the narrow closed space formed in the discharge passage is sharply changed by using a high-speed actuator, and the sudden drop of the pressure is used. It is possible to shut off.

FIG. 1 shows a first embodiment in which the present invention is applied to a dispenser for mounting electronic components on a surface. Reference numeral 1 denotes a first actuator, which is an electromagnetic type actuator using a giant magnetostrictive element or the like; Or an electromagnetic solenoid or the like. In the embodiment, since a dispenser used in an application process with a very small flow rate is applied, a laminated piezoelectric element is used. The first actuator is fixed to the upper housing 2 at the upper end, and is in contact with the upper end surface of the central shaft 3 at the lower end. The central shaft 3 is accommodated in the sleeve 6 so as to be movable in the axial direction.

The first actuator side of the center shaft 3 is integrated with a disc-shaped flat spring 5 having a hinge portion (notch portion) at the upper part. By this flat spring 5, the first
The actuator 1 is always given a preload, and the central shaft 3 can maintain its axial position with high rigidity.

With the above configuration, the central axis 3 moves in the axial direction by the amount of expansion and contraction of the piezoelectric element 1.

Reference numeral 7 denotes a second actuator, which gives a relative rotational movement between the sleeve 6 and a cylinder 8 which houses the sleeve 6 on the discharge side. In the embodiment, a DC servomotor is used, 9 is a motor rotor, 10 is a motor stator, and 11 is a housing for housing the motor stator. The sleeve 6 is supported by bearings 12 and 13.

Reference numeral 15 denotes a discharge unit disposed at the lower end of the cylinder 8, and 14 denotes a discharge nozzle. 16 is a cylinder 8
Reference numeral 17 denotes a thread groove formed on the outer peripheral surface of the sleeve 6. The members 6, 8, and 17 form a fluid transport chamber 18 that sucks in fluid from the outside and pumps the fluid to the discharge side.

A flow control section 19 for controlling the discharge flow rate is provided between the discharge side end face of the central shaft 3 and the opposite face (discharge section 15).

FIG. 2 is an enlarged view of the vicinity of the above-mentioned flow control unit 19, in which reference numeral 20 denotes a discharge-side end surface of the central shaft 3, reference numeral 21 denotes a discharge-side end surface of the sleeve 6, and reference numeral 22 denotes a facing surface of the above-mentioned 20, 21.
Reference numeral 3 denotes a liquid pool formed at the opening of the discharge nozzle 14.

The end surface 20 on the discharge side of the central shaft 3 and the opposing surface 2
2 forms an internal space 24 whose volume changes as the central shaft 3 moves up and down.

FIGS. 2A and 2B show the operation process of this embodiment. That is, by rapidly increasing the distance between the end surface 20 of the central shaft 3 and the opposing surface 22, the pressure in the internal space 24 on the upstream side of the discharge nozzle drops rapidly due to the dynamic pressure effect of the viscous fluid, which can be called the reverse squeeze effect. This shows a process of immediately blocking outflow of the fluid from the discharge nozzle.

In the description of the present invention, the gap between each member and the change in the position of each member are shown in large scale in order to explain the principle in an easy-to-understand manner. In the embodiment, at most several tens to several hundreds of microns. It is.

FIG. 2A shows a state immediately before the discharge is cut off.
The central shaft 3 is stationary, and the discharge-side end face 20 is at the lowermost position. At this stage, the pressurized fluid in the fluid transport chamber 18 passes through a narrow gap (fluid throttle section 25) formed between the discharge-side end surface 21 of the sleeve 6 and the opposing surface 22 and passes through the discharge nozzle 14 to the outside. Discharged.

FIG. 2B shows a state in which the discharge is interrupted, and the central axis 3 is rising as indicated by an arrow in the figure. When the distance h between the end face 20 of the central axis 3 and the opposing face 22 sharply changes, the pressure in the internal space 24 drops rapidly with an extremely fast response. The pressure in the internal space 24: with respect to P, when the atmospheric pressure was set to P _0, the outflow of fluid if the P <P ₀ is blocked. When the central shaft 3 reaches the uppermost stage and the ascending speed becomes zero, the pressure in the internal space 24 rapidly returns, and the discharge starts.

Now, the principle and effects of the present invention will be described in more detail using theoretical analysis.

When a viscous fluid is interposed in a narrow gap between the opposing planes and the interval of the gap changes with time, the fluid pressure is determined by the squeeze action (Squeeze acti
It is obtained by solving the Reynolds equation in the following polar coordinates with the term on).

[0035]

(Equation 1)

In the equation (1), P is a pressure, μ is a viscosity coefficient of a fluid, h is a gap between opposed surfaces, r is a radial position, and t is time. The right side is a term that provides a squeeze action effect that occurs when the gap changes.

Further, in the case where the liquid reservoir 23 is provided at the inlet of the discharge nozzle, the pressure of the liquid reservoir, that is, the pressure Pn on the upstream side of the nozzle is determined in consideration of the compressibility of the fluid.

[0038]

(Equation 2)

In the equation (2), Qs is the inflow amount taking into account the effect of being discharged from the liquid reservoir by the squeeze action, and Qn is the outflow amount discharged from the liquid reservoir to the atmosphere via the discharge nozzle 14. K is the bulk modulus of the fluid,
V is the volume of the liquid reservoir 23.

The upstream pressure Pn of the nozzle required for obtaining the discharge flow rate is obtained by simultaneously solving the above equations (1) and (2).

Hereinafter, the fluid control unit 22 is assumed to have a viscosity of the fluid: μ = 10000 cps, a bulk modulus of elasticity: K = 300 kg / cm ² , and a boundary portion (outer peripheral portion of the fluid throttle unit 25) pressure: Ps = 20 kg / cm ^2. Was analyzed under the conditions shown in Table 1 below to determine the discharge flow rate.

[0042]

[Table 1]

FIG. 3 shows an analysis result of the discharge flow rate obtained under the above conditions.

(1) In the analysis start stage (t = 0), the initial value of the flow rate (pressure) is assumed to be an appropriate value, but quickly converges to a constant value. During 0 <t <0.03 seconds, continuous drawing is performed.

(2) When the piston starts to rise at t = 0.03 seconds, the discharge flow rate rapidly decreases, and 0.003 seconds (3 m
Discharge is stopped immediately after the fall time of about sec).

(3) In the section of 0.03 <t <0.08 seconds, the discharge flow rate is zero. During this interval, the piston is rising at a constant speed. From Table 1, in the example, the piston stroke: Xst = 50 μm, and the piston operation time: T1 = 0.05 sec, so the ascending speed of the piston: v = 50 μm / 0.05 = 1.0 mm / sec.
It is.

(4) When the piston stops at t = 0.08 seconds,
Thereafter, it returns to the state of continuous application promptly with a rise time of about 0.01 sec.

From the above results, it is understood that the discharge can be cut off in the order of 0.01 second or less by the method of the embodiment in which the internal space of the discharge flow path is sharply increased by using the actuator having excellent response.

However, the time when the discharge flow rate is zero is only while the piston is moving up. This shielding time is determined by the limit stroke and the rising speed of the actuator.

FIG. 5 shows an example of an analysis result of the dispenser using the squeeze action effect, and shows a flow velocity vector of the fluid flowing between the sleeve, the discharge-side end face of the central shaft, and the opposing face. (A) shows the state of discharge ON (during continuous application), and (B) shows the state of discharge OFF (discharge interruption).

In the above analysis, the volume of the liquid reservoir 23 is set to be large and the compressibility of the fluid in the liquid reservoir is taken into consideration.
The fall time can be reduced to a point near the limit of the response of the actuator.

[0052] Incidentally, super-magnetostrictive element, the case of an electromagnetic strain element such as a piezoelectric element, typically, the order response of the 10- ⁴ sec is obtained.

An actuator such as an electromagnetic solenoid can be applied, and the responsiveness is reduced by an order of magnitude as compared with an electromagnetic strain element, but the restriction on the stroke (that is, the allowable stop time) is greatly eased.

To facilitate intuitive understanding of the principle of the present invention, the flow control unit 19 will be replaced with an electric circuit model as shown in FIG.

In FIG. 4, Ps is the boundary pressure of the fluid restrictor 25, R0 is the fluid resistance of the fluid restrictor 25, Rn is the fluid resistance of the discharge nozzle 14, and Qp is the flow rate determined by the rising speed of the central shaft 3 and the piston area. The size of the source, Qn, indicates the flow rate passing through the discharge nozzle 14.

Here, the flow rate Qn passing through the discharge nozzle 14
Is

[0057]

(Equation 3)

When Qn <0, that is, when the following conditions are satisfied, the discharge is interrupted.

[0059]

(Equation 4)

From the above equation (4), it can be seen that in order to enable the flow rate control, the fluid restrictor 25 needs to have a fluid resistance of a certain value or more.

The interruption of the discharge amount can be maintained only by the central shaft 3
Only during the ascent, which limits its use as a dispenser.

Therefore, in the present embodiment, the use of a servomotor is used to achieve both the temporary high-speed interruption of discharge and the state of continuously maintaining the interruption by the following method.

That is, by combining the above (1) and (2) of (1) a method of controlling the flow rate by controlling the rotation speed of the motor and (2) a method of rapidly changing the volume of the closed space using a high-speed actuator. In addition, the flow rate control utilizing the advantages of the two and eliminating the disadvantages was realized. At the time of discharge interruption (1) At the same time as the start of raising of the central shaft 3, a command to stop rotation is given to the motor 7. As described above, the rise of the central shaft 3 interrupts the discharge flow rate on the order of 0.01 seconds or less. However, it takes, for example, about 0.03 to 0.05 seconds to stop the rotation of the motor, during which time the central shaft 3 is kept in an ascending state.

(2) At the same time when the motor 7 stops, the center shaft 3 is lowered to a position before the start of the discharge cutoff. The motor 7 is also slowly reversely rotated only during the downward movement. By this operation, after the discharge is shut off, leakage of the fluid from the discharge nozzle can be prevented.

In the embodiment, the steep pressure change due to the change in the volume of the internal space is due to the squeeze pressure generated by changing a narrow gap of several microns to several hundreds of microns. The principle of this squeeze pressure is different from the change in pressure due to, for example, compression and expansion of a piston of an air cylinder.

The latter depends on the compressibility of the fluid, and a change in pressure is accompanied by a time lag with a change in volume.

The responsiveness of the above-described air pulse dispenser is limited because it depends on the compressibility of the fluid.

On the other hand, the former squeeze pressure is due to the dynamic pressure effect of the viscous fluid, and there is no time delay for a change in volume. That is, the pressure increases and decreases immediately with the change in the gap.

In the embodiment, the flow rate control section is constituted by utilizing such an instantaneous increase and decrease of the pressure. Although the present invention can utilize the compression / expansion of a fluid, it is preferable to use the squeeze pressure in terms of responsiveness.

Hereinafter, a second embodiment of the present invention will be described with reference to an enlarged view (FIG. 6) near the flow rate control unit. The parts other than the flow control unit are the same as in the first embodiment.

In the previous embodiment, high-speed interruption of discharge was achieved by generating a negative pressure in the flow control unit. Instead of this method, the discharge flow rate was controlled by increasing or decreasing the flow path resistance. Is, of course, possible.

Reference numeral 50 denotes a conical convex portion formed at the end of the central shaft 51, 52 denotes a concave portion formed on the discharge surface side of the opposing surface, 53 denotes a housing, 54 denotes a sleeve, and 55 denotes a thread groove (not shown). ), 56 is a fluid transport chamber, 57 is a cylinder,
58 is a discharge nozzle.

When the center shaft 51 driven by the first actuator is at the raised position, the gap between the convex portion 50 and the concave portion 52 is large and the fluid resistance is small. Is discharged smoothly.

When the central shaft 51 is at the lowered position,
When the gap between 0 and the concave portion 52 is small and the fluid resistance is large,
The discharge amount of the fluid is suppressed.

FIG. 7 shows a third embodiment of the present invention, which shows another embodiment of the flow control section formed between the discharge-side end face of the central shaft 150 and the opposite face (discharge section 51). .

Reference numeral 152 denotes a sleeve, 153 denotes a discharge nozzle,
Reference numeral 154 denotes a concave portion formed on the surface of the central shaft facing the discharge side end surface 155, and reference numeral 156 denotes a fluid transport chamber.

When the central axis 150 is raised and lowered, the flow path area changes as S = πdδ. Even if the actuator that drives the central shaft 150 has a small stroke,
By increasing the outer diameter d of 50, the range in which the fluid resistance (that is, the flow rate) can be controlled can be made sufficiently large by this configuration.

This embodiment can be applied to the first embodiment as it is except for the vicinity of the flow control unit in FIG.

Although any of the first to third embodiments may be used, high frequency vibration (or high frequency of high frequency or higher) is applied to the center axis by utilizing the fact that the electromagnetic strain element has high frequency characteristics. If given, the rheological fluid's flowability can be improved. In this case, there are the following cases in which the high frequency vibration is applied.

Only high frequency vibration is applied to the central axis.

While controlling the flow rate by increasing or decreasing the flow path resistance of the discharge section, high-frequency vibration is superimposed on a low frequency for the flow rate control.

High frequency vibration is applied to the central axis only when the discharge is opened or when the discharge is in a transient state.

Which of the above (1) to (5) is selected may be selected according to the purpose of the coating process, the characteristics of the coating material, and the like. In the configuration of the present embodiment, the transport fluid can apply vibration only to the vicinity of the flow rate control unit at the final stage of discharge, so that the negative effect of applying vibration to the powder fluid for a long time can be avoided.

Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

This embodiment shows a case where a giant magnetostrictive element is used for the first actuator.

In this embodiment, the position of the center axis in the axial direction is controlled by a drive shaft penetrating the giant magnetostrictive element using a hollow giant magnetostrictive element.

Reference numeral 200 denotes a first actuator. The first actuator 200 includes an upper plate 201.
It is fixed to

The first actuator side of the central shaft 202 is integrated with a disc-shaped flat spring 203 having a hinge portion (notch portion) at the upper part. The central portion of the upper end of the central shaft 202 is in contact with the drive shaft 219 of the first actuator under a preload.

The lower end of the center shaft 202 is
It is stored so as to be able to move in the axial direction in the inside 04. With the above configuration, the center shaft 202 moves in the axial direction by the amount of expansion and contraction of the first actuator.

Reference numeral 205 denotes a second actuator, which gives a relative rotational movement between the sleeve 204 and a cylinder 206 which houses the sleeve 204 on the discharge side. In this embodiment, a DC servo motor is used, 207 is a motor rotor, 208 is a motor stator, and 209 is an intermediate housing that houses the motor stator. Also sleeve 2
04 is supported by a bearing 211 and a bearing 212 whose outer ring side is held by an upper housing 210.

Reference numeral 213 denotes a discharge unit disposed at the lower end of the cylinder 206, and reference numeral 214 denotes a discharge nozzle. Reference numeral 215 denotes a suction hole formed in the cylinder 206, and 216 denotes a thread groove (not shown) formed on the outer peripheral surface of the sleeve 204. The members 204, 206, and 216 form a fluid transport chamber 217 that sucks in fluid from the outside and pumps the fluid to the discharge side. A flow control unit 218 that controls the discharge flow rate is provided between the discharge side end surface of the central shaft 202 and the discharge unit 213 on the opposite surface.

Reference numeral 219 denotes a drive shaft driven by the first actuator. Reference numeral 220 denotes a cylindrical giant magnetostrictive rod made of a giant magnetostrictive material. The giant magnetostrictive rod 220 includes bias permanent magnets (A) 221 and (B). It is fixed between the rear yoke 223 and the upper plate 201 which also serves as a yoke material, with the upper and lower plates 222 sandwiched therebetween.

Reference numeral 224 denotes a magnetic field coil for applying a magnetic field in the longitudinal direction of the giant magnetostrictive rod 220. Reference numeral 225 denotes a cylindrical yoke which is housed in the housing 226.

The permanent magnets (A) and (B) increase the operating point of the magnetic field by applying a magnetic field to the giant magnetostrictive rod 220 in advance. The magnetic bias reduces the linearity of the giant magnetostriction with respect to the strength of the magnetic field. Can be improved. 220 → 221 → 223 →
From 225 → 201 → 222 → 220, the giant magnetostrictive rod 2
20 form a closed-loop magnetic circuit for controlling the expansion and contraction. That is, the members 201 to 225 constitute a giant magnetostrictive actuator that can control the amount of expansion and contraction of the giant magnetostrictive rod in the axial direction by the current applied to the magnetic field coil.

The permanent magnets for biasing may be arranged in any location and in any shape as long as they can form a closed-loop magnetic circuit.

A bias spring 228 for applying a mechanical axial pressure to the giant magnetostrictive rod 220 is provided between the rear yoke 223 and the upper lid 227. Since the compressive stress is always applied to the giant magnetostrictive rod 220 in the axial direction by the bias spring 228, the drawback of the giant magnetostrictive element which is weak in tensile stress when repeated stress is generated is eliminated.

At the center of the upper cover 227, a drive shaft 219
A displacement sensor 229 for detecting the position of the shaft end face is adjustable.

In the case of a conventional actuator using an electromagnetic strain element, for example, referring to FIG. 1, in order to detect the displacement of the output shaft (corresponding to the center shaft 3 in FIG. 1), for example, a ring is attached to the output shaft. It is necessary to arrange a displacement sensor so as to detect the axial position of the ring. In this case, there is a problem that the detection accuracy is affected by the inclination of the ring with respect to the axis, or the like. If the conventional method is applied to a dispenser, there is a problem that the outer diameter of the dispenser becomes large.

In this embodiment, since the displacement sensor is disposed on the shaft core on the side opposite to the discharge side, the displacement of the central axis can be detected with high accuracy. In addition, since the length of the central shaft can be shortened, the rigidity of the rotating part can be increased, and the entire device including the actuator can be made compact.

In this embodiment, a giant magnetostrictive element is used for the first actuator, but a hollow laminated piezoelectric element may be used. Even in this case, if a preload is applied to the piezoelectric element on the rear side (the side opposite to the discharge side), it is possible to detect the axial displacement from the end of the shaft.

[0101]

According to the coating apparatus using the present invention, the following effects can be obtained. 1. Ultra high-speed cutoff of discharged fluid is possible. At this time, the entire flow path of the fluid from the suction port to the discharge port can always be kept in a non-contact state, so that it is possible to cope with a powder and a particulate material mixed. 2. The discharge amount can be arbitrarily varied with high speed and high accuracy. 3. It is possible to have a screw groove type feature in which the discharge amount is hardly dependent on a change in environmental temperature (change in viscosity) or a gap between the nozzle and the discharge surface. 4. Since high-frequency vibration can be applied to the rheological fluid immediately before discharge, the discharge amount can be made more precise.

If the present invention is applied to, for example, a surface-mounted dispenser, a phosphor coating for a PDP or a CRT display, the advantages can be fully exhibited, and the effect is extremely large.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a dispenser according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a fluid control unit according to the above-described embodiment, in which (a) shows a coating state and (b) shows a state in which discharge is interrupted.

FIG. 3 is a diagram showing a flow rate characteristic when the discharge is cut off in the embodiment.

FIG. 4 is a diagram showing an electric circuit model of the embodiment.

FIG. 5 is a diagram showing a flow velocity vector as an analysis result.

FIG. 6 is a diagram showing a flow control unit of a dispenser according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a flow control unit of a dispenser according to a third embodiment of the present invention.

FIG. 8 is a front sectional view of a dispenser according to a fourth embodiment of the present invention.

FIG. 9 is a front sectional view of a conventional air pulse dispenser.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st actuator 3 Center axis 6 Sleeve 7 2nd actuator 8 Housing (cylinder) 14 Discharge hole 16 Suction hole

Claims (2)

[Claims] 1. A central axis provided through the inside of a sleeve, a first actuator for relatively linearly driving the central axis and the sleeve, a housing for accommodating the sleeve, and a housing formed on the housing. A second actuator for providing relative rotational movement between the sleeve and the housing, and a fluid formed between the sleeve and the housing and communicating with the suction and discharge holes; In a coating apparatus including a transport chamber and means for pumping a fluid in the fluid transport chamber, a volume formed between the discharge side end of the central shaft and the housing by axial movement of the central shaft or A coating apparatus, wherein a discharge flow rate is adjusted by changing a flow path resistance. 2. The coating apparatus according to claim 1, wherein the means for pressure-feeding the fluid in the fluid transport chamber is a thread groove formed on a relative movement surface between the central shaft and the sleeve.