CN102553754A - Piezoelectric-gas mixture control type fluid jet device - Google Patents

Abstract

The invention provides a novel piezoelectric-gas mixture control type fluid jet device, which is simple in structure and convenient in maintenance. The technical scheme includes that the piezoelectric-gas mixture control type fluid jet device comprises a jet unit, a gas control unit and a piezoelectric driving control unit, the jet unit comprises a nozzle, a needle valve, a connecting column, a rubber gasket, a diaphragm spring and a liquid cavity, the gas control unit comprises a gas pressure cavity, a return spring, a gas valve and a gas valve seat, and the piezoelectric driving control unit comprises a piezoelectric stack, an adjusting spring sheet and a pre-tightening device. The novel piezoelectric-gas mixture control type fluid jet device can be applied to the fields of precision chemistry, quantitative drug distribution, biomedicine and the like, is particularly applicable to the technical field of high-viscosity fluid dispensing in semiconductor package, and is used for chip fixation in electronic package, surface mount, underfilling, fluorescent powder coating in liquid crystal display panel and the like.

Description

A Piezoelectric-Gas Mixed Control Type Fluid Injection Device

technical field

The invention relates to a piezoelectric-gas mixing control type fluid injection device, which belongs to the field of microelectronic machinery.

Background technique

With the development and maturity of microelectronics industry, materials and control technologies, microelectromechanical systems have developed rapidly in recent years. As an important branch of microelectromechanical systems, microfluidic systems have important application prospects in micro-delivery of drugs, micro-injection of fuel, packaging of integrated electronic components, cooling, and microchemical analysis due to their ability to accurately detect and control flow.

The invention patent "piezoelectric stack pump" (application publication number CN 101216027A) proposes a new piezoelectric stack pump with large flow rate and high output pressure, which is characterized in that the piezoelectric stack pushes the piston under the action of external excitation, The piston drives the metal sealing diaphragm to move up and down to realize the volume change of the pump chamber. Two one-way valves are installed at the bottom of the working chamber, which are the water inlet one-way valve and the water outlet one-way valve, which are respectively connected to the water inlet and the water outlet. The change realizes the one-way inflow and outflow of liquid. This piezoelectric stack pump has poor self-priming properties for viscous fluids, and even the pump cannot work normally, and the valves are poorly sealed, and the fluid is easy to flow back and other disadvantages.

In the development of microelectronics technology, integrated circuits are becoming more and more complicated and miniaturized, and semiconductor packaging requires smaller sizes, more leads, and denser interconnections, etc., which promotes the development of integrated circuits and packaging technologies. Increasingly demanding. In microelectronic packaging, fluid dispensing technology is more and more widely used.

The invention patent "jet dispensing valve" (application publication number: CN 201008812Y) proposes a solenoid valve jet dispensing device, which is characterized in that the glue with a certain pressure is passed into the nozzle cavity with a firing pin, and must The air pressure of the pressure is passed into the air pressure chamber equipped with the piston and the piston return spring, the on and off of the gas is controlled by the solenoid valve switch, and the up and down movement of the piston is controlled by the air pressure to drive the up and down movement of the striker. This structure can spray colloid with a certain viscosity. It solves some problems of contact dispensing, but because the air pressure is used to control the up and down movement of the piston, if the air pressure fluctuates, the displacement of the piston will change, resulting in the change of the displacement of the firing pin, which makes the size of the glue point inconsistent, and the use of the piston device makes the firing pin The speed of the up and down movement is not high, and when the viscosity of the colloid is high, it is not easy to spray out quickly, and the structure is more complicated.

To sum up, the piezoelectric pump can achieve a small amount of fluid output, but it is easily affected by the load when the fluid is delivered quantitatively, the output force is small, the precision is low, and the carrying capacity is weak. Issues such as poor consistency and complex structure control need to be further improved.

Contents of the invention

The invention provides a piezoelectric-gas mixing control type fluid injection device to solve the problems that the piezoelectric pump is easily affected by the load when the fluid is quantitatively delivered, the output force is small, the precision is low, and the carrying capacity is weak, and the current dispensing technology There are problems of poor glue point consistency and complex structure control in the system.

To achieve the above object, the present invention adopts the following technical solutions:

A piezoelectric-gas mixing control type fluid injection device, comprising three unit injection units, a gas control unit and a piezoelectric drive control unit, characterized in that the injection unit includes a nozzle, a needle valve, a connecting column, and a rubber gasket , Diaphragm spring, liquid cavity, gas control unit includes air pressure cavity, return spring, gas valve, gas valve seat, piezoelectric drive control unit includes piezoelectric stack, adjustment spring piece, pretensioning device.

The nozzle of the present invention is provided with a needle valve, the upper end of the needle valve and the beryllium bronze diaphragm spring are connected together by bolts, the upper end of the beryllium bronze diaphragm spring is provided with a compression spring, and the lower part of the piezoelectric stack is provided with an adjustment spring diaphragm and It is connected with the air valve, and the upper end of the piezoelectric stack is connected with the pretensioning device.

The diaphragm spring of the present invention adopts a circular beryllium bronze diaphragm whose periphery protrudes upwards, and has better elasticity.

The piezoelectric stack of the present invention is connected with the wedge-shaped pre-tensioning device through screws. The wedge-shaped pre-tensioning device consists of two wedge-shaped blocks, a pre-tightening bolt, an adjusting bolt and an upper cover. Screwing in the pre-tightening bolt can pre-tighten Piezo stack, preload can be reduced by screwing in the adjusting bolt.

The lower end of the piezoelectric stack in the present invention is provided with an adjustment spring diaphragm to ensure the alignment between the piezoelectric stack and the gas valve, and the piezoelectric stack controls the opening and closing of the gas valve.

The advantage of the present invention is that it proposes a piezoelectric-gas mixing control type fluid injection device, which can realize quantitative delivery, quantitative distribution of liquid, and high-viscosity fluid dispensing in microelectronic packaging, etc., and can be widely used in industrial automation Precise measurement of infusion, oil supply, cleaning in processing equipment, chemical preparations, etc., especially in high-viscosity fluid dispensing technology in microelectronic packaging. Compared with existing dispensing technology, jet dispensing technology is used. Thus, a high-speed, high-quality and easy-to-maintain dispensing device is provided for the dispensing process.

Description of drawings

Figure 1 is a structural diagram of a piezoelectric-driven jet dispensing device

Fig. 2 is the structural diagram of adjusting the spring leaf (10)

Fig. 3 is a structural diagram of diaphragm spring (5)

Figure 4 is the front view and cross-sectional view of the wedge-shaped lower end pretensioning block

Figure 5 is the front view and cross-sectional view of the wedge-shaped upper end pretensioning block

Detailed ways

Referring to FIG. 1 , a piezoelectric-gas mixing control type fluid injection device of the present invention includes three unit injection units, a gas control unit and a piezoelectric drive control unit. The injection unit includes a nozzle (1), a needle valve (2), a connecting column (3), a rubber gasket (4), a diaphragm spring (5), a liquid cavity (21), and the gas control unit includes a pneumatic cavity (20 ), a return spring (8), an air valve (9), an air valve seat (19), and the piezoelectric drive control unit includes a piezoelectric stack (11), an adjustment spring (10), and a pretensioning device. The nozzle (1) is in interference fit with the liquid chamber (21) and is equipped with a sealing ring (22), the needle valve (2) is threadedly connected with the connecting post (3), and the connecting post (3) and the diaphragm spring (5) are used The nut (6) is connected with the rubber gasket (4), the piezoelectric stack (11) is connected with the pretensioner with the connecting screw (12), the piezoelectric stack cavity (18), the air valve seat (19), the air pressure The cavity (20) and the glue cavity (21) are connected by fixing bolts (23).

The needle valve (2) of the present invention is connected with the diaphragm spring (5) through the connecting column (3), nut (6) and rubber gasket (4), and the upper and lower ends of the diaphragm spring (5) are provided with sealing rings (22) It is tightly compressed with the air pressure cavity (20) and the liquid cavity (21) to prevent air leakage, and at the same time ensures the convenience of maintenance, disassembly and cleaning of the nozzle (1) and needle valve (2).

In the present invention, the diaphragm spring (5) is compressed by the compression spring (7), thereby driving the needle valve (2) to compress the nozzle (1) through the connecting column (3).

The lower end of the piezoelectric stack (11) of the present invention is connected with the piezoelectric stack cavity (18), the pneumatic valve seat (19) and the sealing ring (22) by adjusting the spring piece (10), ensuring that the piezoelectric stack (11) ) and the air valve (9) to prevent the piezoelectric stack (11) from depressing the air valve (9) during deflation, so that the gas in the air pressure cavity (20) cannot be discharged well.

When the present invention is applied to quantitative liquid distribution, it can be realized by controlling the number of injections.

Its working principle is: the air pressure cavity (20) is passed into a certain pressure of high-pressure gas, and the liquid cavity (21) is passed into a certain pressure of high-pressure liquid. The upward pressure F ₁ in (21), the downward pressure F ₂ in the air chamber (20) and the downward pressure F ₃ in the compression spring (7), and F ₂ +F ₃ >F ₁ , so the diaphragm spring ( 5) Bulge downwards, driving the connecting column (3) and the needle valve (2) to press the nozzle (1), the needle valve (2) closes the nozzle (1), the piezoelectric stack (11) does not receive the drive signal, and the gas The valve (9) is closed under the combined action of the upward gas pressure _F4 in the air pressure chamber (20) and the upward pressure _F5 of the return spring (8), when the piezoelectric stack (11) When the driving signal is obtained, the piezoelectric stack (11) outputs a certain force F and displacement, and F>F ₄ +F ₅ , so the air valve (9) is opened, and the gas in the air pressure cavity (20) is released from the air valve (9 ), the air pressure in the air pressure chamber (20) decreases because the air inlet area S ₁ of the air inlet pipe entering the air pressure chamber (20) is smaller than the surrounding air outlet area S ₂ when the air valve is opened. The upward pressure F ₁ in the liquid cavity (21) at the lower part of the diaphragm spring (5) is greater than the air pressure F ₆ in the air pressure cavity (20) and the downward force F ₇ of the compression spring (7), that is, F ₁ > F ₆ +F ₇ , so the diaphragm spring (5) bulges upwards, driving the connecting column (3) and the needle valve (2) to lift up together, and the needle valve (2) moves away from the nozzle (1) to form a certain gap. At this time, the liquid flows into the spray hole of the nozzle (1) through the gap between the needle valve (2) and the nozzle (1). The driving signal of the piezoelectric stack (11) disappears, and the gas valve (9) of the piezoelectric stack (11) is closed under the joint action of the gas pressure in the air pressure chamber (20) and the return spring (8), and the air pressure chamber (20) The gas pressure in ) recovers quickly so that the diaphragm spring (5) is subjected to the downward pressure of the gas pressure F ₂ in the air cavity (20) and the pressure F ₃ of the compression spring (7) and is greater than the pressure in the liquid cavity (21). The upward pressure F ₁ of the diaphragm spring (5), that is, F ₂ + F ₃ > F ₁ , so the diaphragm spring (5) bulges downward, driving the needle valve (2) to quickly contact the nozzle (1) at a certain speed. The contact is closed, and the needle valve (2) generates a certain acceleration impact force during the closing process, thereby prompting the liquid to be ejected from the spray hole of the nozzle (1).

The present invention adopts the conventional air pressure system control method, and the compressed air used passes through the micro-mist separator to filter and separate the water and impurities in it, so as to ensure the quality of the compressed air and ensure the normal use of the dispensing device.

Claims (5)

1. A piezoelectric-gas mixing control type fluid injection device, comprising three unit injection units, a gas control unit and a piezoelectric drive control unit, is characterized in that: the injection unit includes a nozzle (1), a needle valve (2 ), connecting column (3), rubber gasket (4), diaphragm spring (5), liquid chamber (21), the gas control unit includes air pressure chamber (20), return spring (8), air valve ( 9), the valve seat (19), the piezoelectric drive control unit includes a piezoelectric stack (11), an adjustment spring (10), and a pretensioning device. 2. A piezoelectric-gas mixing control type fluid injection device according to claim 1, characterized in that: a needle valve (2) is arranged in the nozzle (1), and the upper end of the needle valve (2) is connected with beryllium bronze The diaphragm springs (5) are connected together by bolts (6), the upper end of the beryllium bronze diaphragm spring (5) is connected with a compression spring (7), and the piezoelectric stack (11) is provided with an adjustment spring diaphragm (10 ) and is connected with the air valve (9), and the upper end of the piezoelectric stack (11) is connected with the pretensioning device. 3. A piezoelectric-gas mixing control type fluid injection device according to claim 1, characterized in that: the diaphragm spring (5) adopts a circular beryllium bronze diaphragm whose periphery protrudes upwards, which has better flexibility. 4. A piezoelectric-gas mixing control type fluid injection device according to claim 1, characterized in that: the piezoelectric stack (11) is connected to the wedge-shaped pretensioning device through a screw (12), and the The wedge-shaped pre-tightening device consists of upper and lower wedge-shaped blocks (13) (14), pre-tightening bolts (15), adjusting bolts (16) and upper cover (17). Screwing in the pre-tightening bolts (15) can pre-tighten the piezoelectric Stacking (11), screwing in the adjusting bolt (16) can reduce the preload. 5. A piezoelectric-gas mixing control type fluid injection device according to claim 1, characterized in that: the lower end of the piezoelectric stack (11) is provided with an adjustment spring diaphragm (10) to ensure that the piezoelectric stack (11) The alignment between the stack (11) and the gas valve (9) is neutral, and the piezoelectric stack (11) controls the opening and closing of the gas valve (9).

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