JP2013139745A - Viscous non-contact injection method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a viscous non-contact injection method and a device.SOLUTION: There are provided a method and a device for dispensing a high viscosity material of a minute amount from an injection needle by using a nozzle plate provided with an injection chamber having an upper face constituted of a diaphragm and a bottom face fluid-communicating with the injection needle when an injection mechanism is driven. The fluid flows in from a flow-in channel to the chamber, deforms the diaphragm to block the channel, and is injected from the chamber by injecting the droplet of the fluid from the needle. A metering chamber driven by the diaphragm and/or a container chamber can be used optionally for the supply of the fluid to the injection chamber.

Description

  The present invention relates to a viscous non-contact injection method and apparatus.

  In the semiconductor, electronics, and life science industries, viscous fluids are frequently dispensed. In the semiconductor industry, the application of microdroplets of viscous material is often required to reduce device size, weight, and power consumption. Non-contact dispensing is preferred because the bare silicon die is very fragile and any contact with the surface of the semiconductor chip is detrimental. Further, in order to improve the strength and reliability of bonding, printed circuit boards (PCBs) often require a small chip to be attached to the wiring board using a viscous adhesive. . Many of the adhesives used in the production of PCBs are premixed two-part epoxies, but this adhesive changes in viscosity over time, and this change in viscosity causes dispenser malfunctions. Accordingly, there is a need for a dispensing method and apparatus that is less susceptible to changes in viscosity.

  In the life science industry, clinical trials and drug development for investigating diseases and medical conditions are becoming increasingly sophisticated. Experiments need only trace amounts of reagents, proteins, or compounds. The volume of low viscosity fluid microdroplets is typically in the microliter and nanoliter range. In these applications, it is preferable to supply the fluid in a non-contact manner, because microdroplets of viscous fluid are often dispensed deep into the microwell. Such dispensing needs to be very precise and reproducible. Otherwise, incorrect results may be produced. Fluids in the life science industry tend to be in short supply and are often very expensive. Accordingly, there is a need for an injection device that minimizes the loss of this expensive fluid in a viscous jet. In addition, biological materials are very susceptible to contamination and cross-contamination, but existing equipment is complex and difficult to keep clean and can contribute to contamination or cross-contamination. Thus, there is also a need for a spray device in which the components in contact with the fluid are disposable or can be easily cleaned.

  Viscous jet technology is similar to ink jet technology used in computer printers. In either case, small droplets of fluid are ejected from the nozzle and “fly” to the substrate in a non-contact manner. As used herein, the term “injection” refers to non-contact dispensing relative to contact dispensing. In the process of contact dispensing, the fluid droplets at the end of the dispensing tip contact the substrate of interest and “wet” or stick to the surface and remain on the surface as the dispensing tip leaves. In the case of inkjet technology, ink with a viscosity very close to water (<10 millipascal seconds (mPas)) is ejected. In the case of the viscous injection technique, a highly viscous fluid (> 50 mPas) can be injected. Examples of viscous fluids include adhesives, fluxes, oils, lubricants, conformal coatings, paints, slurries, UV inks, solvents, reagents, proteins, enzymes, and the like. The high viscosity fluid herein has a viscosity greater than 50 mPas.

  In order to generate free-flying jet droplets, it is necessary to rapidly obtain a high pressure state. In this state, sufficient momentum is provided for the fluid to pass through the nozzle and the fluid becomes free-flying droplets with the appropriate exit velocity. Here, there is a unique range of exit velocities that produce high quality injection. Accurate control of rapid high pressure conditions and elimination of momentum transmission loss to control the fluid exit velocity from the dispensing orifice will produce a reproducible high quality jet of viscous fluid. It is valid.

  There are several ways to rapidly generate high pressure conditions. For example, one such viscous injection technique uses a reciprocating solenoid valve. When the fluid container is pressurized to a predetermined level, the fluid flows out of the container and through a passage extending through a valve assembly having a valve seat disposed near the outlet end in communication with the dispensing orifice. The fluid flow is divided into microdroplets by a reciprocating valve shaft that cycles by energization of the air solenoid valve. Due to the closing action of the valve and the impact when the valve shaft collides with the valve seat, a high pressure state is rapidly generated that ejects the droplet, so that the droplet “flys” to the substrate in a non-contact manner. The size of the ejected droplet depends on the fluid flow rate, the size of the valve shaft and valve seat, and the cycle time of the reciprocating valve shaft. Here, since the movable mechanical element is arranged in the fluid flow, a dynamic fluid seal is required. This dynamic seal wears over time and generates particles due to the sliding action of the seal. It is not only the seal that wears, but also the sliding parts often wear and generate particles. These particles are released into the fluid as contaminants and can be a significant problem for high purity fluids used in life science applications. Wet moving parts are difficult to clean with flushing and may require disassembly and costly and time consuming repairs or replacements. Also, when using a fluid seal, the moving parts must be constructed of a wear resistant material or provided with a wear resistant coating, which increases the overall design cost. Cleaning is also an issue for the internal shape that supports the reciprocating valve shaft, and disassembly is always necessary, especially to keep the area around the dynamic seal area clean. Therefore, there is a need for an injection device and technique that does not require a dynamic fluid seal.

  Another example of rapidly generating a high pressure state is a viscous injection technique using an elastic diaphragm that is impacted by an external element. The fluid from the pressurized container flows into an injection chamber provided on one side surface near the elastic diaphragm. Here, the impact means that the volume of the chamber rapidly changes by colliding with the diaphragm covering the chamber, and a high-pressure state in which a liquid droplet is discharged is rapidly generated. However, this viscous jet technology cannot always satisfy the requirements of volume accuracy and reproducibility for each droplet accurately. The pressure in the fluid container is released rapidly and the flow of fluid into the ejection chamber stops. However, the rate of decrease in container pressure is often low, and a small amount of fluid leaks from the orifice and remains attached to the outer surface of the orifice. Fluid adhering to the outside of the orifice can affect the volume of subsequent ejected droplets, which can lead to a drop in accuracy for each droplet. Alternatively, it can cause the droplets to stick to the orifice. Therefore, there is a need for a viscous jet technique that minimizes the possibility of unwanted fluid remaining outside the orifice after jetting a droplet.

  Another example of rapidly producing a high pressure condition is a viscous jet technique with a fluid tube having a flexible tube with a first end connected to a fluid container and a dispensing orifice at the second end. Is mentioned. A displacer connected to the piezoelectric element partially compresses the tube near the outlet end and displaces the tube by a volume to rapidly create a high pressure condition and eject a fluid droplet. The fluid is refilled into the tube by capillary force. When refilling a tube with capillary forces, the use of a high viscosity fluid limits the refill rate. Also, the volume of the ejected droplet is not equal to the volume displacement of the tube. This volume displacement drives the fluid in two directions: outflow from the orifice and backflow into the container. The volume of fluid flowing in each direction is determined by the inherent flow resistance and elasticity of each channel. The flow balance between the fluid flowing out of the orifice and the fluid flowing back into the container is very important in this type of injector. If the flow balance changes due to fluid temperature, pressure, or viscosity, the volume per droplet can change significantly. Also in this injection technique, if the tube material is gradually distorted by use and the displacement increases and decreases with time, the volume of each droplet may change. Therefore, there is a need for an injection technique that allows only fluid outflow in the injection chamber.

  In the industry, active metering devices such as syringe pumps, Auger pumps, or peristaltic pumps can accurately meter fluid and fluid volumes that are substantially independent of downstream flow channel temperature, viscosity, and flow characteristics. well known. Various active metering devices can be used to refill the injection chamber, but factors such as cost, simplicity, size, maintainability, and ease of cleaning must be considered. For example, syringe pumps are typically large and bulky, making it difficult to mount in close proximity to the injection chamber assembly and lengthening the fluid flow path between the pump and the solenoid valve. If the fluid resistance and elasticity are high, the pressure rise is slow in this long connecting pipe, so that the response time becomes long. In addition, since it is necessary to provide a one-way valve in series between the syringe pump and the container, the cost of the system increases and the complexity increases. If it is an Auger pump, the flow path length between a pump and an injection chamber can be restrained by mounting close to the injection chamber. However, an Auger pump requires a feed screw that rotates inside a chamber of suitable shape. When the internal mechanism becomes complicated, the cost becomes high, it is affected by wear, and cleaning becomes difficult. For this reason, the feed screw type Auger pump is not preferable when it is necessary to avoid cross contamination. Peristaltic pumps are often used in applications where cross contamination needs to be avoided. A typical rotary peristaltic pump uses a plurality of rollers that generate a squeezing point that moves the occlusion of fluid within the capture tube. The tubing material is typically a low cost, flexible elastomeric silicone that is easy to remove and install from the pump, eliminating the need to clean the wet fluid flow path. However, in order to perform the throttling operation, the pipe is long and the volume of the internal fluid is considerable. When an expensive fluid is used, a large loss of fluid when replacing the tube is not preferable. Therefore, there is a need for a spray chamber refill method that can accurately meter the amount of fluid, is responsive and cost effective, and is easy to clean.

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LIQUIDYN, Dispensing System Data Sheet, Micro-dispensing valve P-jet PVA, Data Sheet, Non-contact micro dispensing valve, specifications AEROJET, Data Sheet, Non-contact jet dispenser for high viscous materials EFD, Data Sheet, PicoDot Jet Dispensing System ASYMTEK, Data Sheet, High-speed Piezo jet dispensing for liquid crystal fluids

An object of the present invention is to provide a non-contact injection method and apparatus for accurately injecting a small amount of viscous fluid.
Another object of the present invention is to provide an improved ejection chamber assembly for ejecting a constant volume droplet of viscous fluid. As used herein, the term “jet chamber assembly” refers to a space that contains a volume of fluid and communicates with a dispensing orifice and is located downstream of a forcing element. The forcing element as defined herein is a means of rapidly creating a high pressure condition in the jet chamber assembly to impart momentum to a volume of fluid and eject fluid droplets out of the orifice.

Another object of the present invention is to provide an improved method of filling a jet chamber assembly with a reproducible and known amount of viscous fluid.
Another object of the present invention is to fill the injection chamber assembly with actively metered fluid.

Another object of the present invention is to provide an improved jet chamber assembly capable of containing an adjustable amount of fluid.
Another object of the present invention is to provide a method of filling an injection chamber assembly with an adjustable amount of fluid.

It is another object of the present invention to provide an improved injection chamber in which the fluid flow during the injection cycle is substantially toward the dispensing orifice.
Another object of the present invention is to provide an improved viscous injection device that is easy to clean and minimizes cross contamination between fluids.

Another object of the present invention is to provide an improved jetting device that minimizes the volume of fluid it contains.
It is another object of the present invention to provide an improved viscous injection device that minimizes the volume between the fluid source and the injection chamber assembly.

Another object of the present invention is to provide an improved injection method that does not require a sliding dynamic fluid seal.
Another object of the present invention is to provide an improved injection chamber assembly that removes unwanted fluid from a dispensing orifice.

  It is another object of the present invention to provide an improved injection chamber assembly in which fluid contacting parts can be replaced cost-effectively.

  These one or more objects are advantageously achieved by providing a viscous injection device for injecting a small amount of viscous fluid as detailed herein. The injection chamber assembly apparatus may comprise a pressurized fluid supply source, an injection chamber, a resilient diaphragm, an inflow channel, an outflow path, an orifice, a support structure, and a pressure supply source. The injection chamber has a correspondingly flexible elastic diaphragm as its upper wall. This diaphragm is contained between the injection chamber and the support structure and can be easily removed for cleaning and replacement. The injection chamber is in communication with the dispensing orifice by an outlet tube. The ejection chamber is also connected to a fluid inflow channel in communication with a pressurized viscous fluid supply source. The fluid inflow channel is at least partially in communication with the elastic diaphragm during part of the operation of the device. Fluid flows from the fluid source through the inflow channel into the injection chamber. The diaphragm is rapidly deformed by the pressure means to separate from the support structure. The diaphragm enters the interface between the injection chamber and the fluid inflow channel so that its initial deflection prevents fluid flow from the source. This includes a volume of fluid between the injection chamber and the dispensing orifice. The diaphragm continues to deform into the injection chamber and couples equiangularly with the side of the injection chamber. This displaces a known amount of fluid contained in the ejection chamber and ejects a droplet of fluid to fly from the dispensing orifice to the substrate. The pressure means is depressurized and the diaphragm begins to relax and moves away from the side of the injection chamber, preferably in a flat state. Before the diaphragm is retracted and the inflow channel is opened, a suck back condition is created and fluid is pulled away from the orifice and pulled into the outflow path, creating a space between the fluid and the orifice. If unnecessary fluid adheres to the outside of the orifice, it is also pulled backward. When the diaphragm is retracted and the inflow channel is opened, fluid enters the injection chamber from the source to fill a portion of the space and this operation is repeated. In order to repeatedly return the diaphragm to the position before deformation, a vacuum is considered unnecessary. On the other hand, when the diaphragm 24 deformed by drawing a vacuum through the air pipes 28, 52, 54 is retracted, the cycle time during which the fluid can be ejected from the ejection chamber 12 can be shortened. The hardness, thickness, and material of the diaphragm is such that the viscosity of the fluid being jetted is such that the diaphragm 24 is not flattened at a sufficiently low speed so that air is not trapped in the jetted viscous fluid. It is convenient to select in relation. The retraction to this flat state is preferably done without pulling a vacuum through the air tubes 28, 52, 54, which alternate with the positive pressure that deforms the diaphragm into the various chambers.

  Also advantageously provided is an injection chamber assembly apparatus comprising a fluid source, an injection chamber, an elastic diaphragm, an inflow channel, an outflow channel, an orifice, a support structure, and a mechanical forcing element. In this assembly, the diaphragm is rapidly deformed by a mechanical forcing element. This mechanical forcing element may be included in the support structure of the diaphragm. This causes the diaphragm to first enter the interface between the injection chamber and the fluid inlet channel so as to prevent fluid flow from the source. A volume of fluid is then contained between the injection chamber and the dispensing orifice. The diaphragm continues to deform into the injection chamber and is preferably joined equiangularly with the side of the injection chamber. However, it does not have to be equiangular with the side surface of the injection chamber. This displaces a known amount of fluid contained therein, ejecting fluid droplets and flying from the dispensing orifice to the substrate. The mechanical forcing element retracts and the diaphragm can be relaxed. Before the diaphragm is retracted and the inflow channel is opened, a suck back condition is created and fluid is pulled away from the orifice to create a space as described above. This will be described in more detail below.

  A method for injecting a small amount of viscous fluid is also advantageously provided. In this method, a viscous fluid is allowed to flow from a pressurized fluid container through an inflow channel into an injection chamber for a predetermined time. Conveniently, a fast operating valve is provided between the pressurized container and the injection chamber. The amount of fluid flowing into the injection chamber can be gradually adjusted according to the openable time of the valve. When the desired amount of fluid enters the injection chamber, the valve is closed to close fluid communication with the injection chamber. For this reason, the refill cycle is independent of the injection cycle. When the injection cycle begins, the fluid inflow channel is preferably closed at or within the injection chamber, further reducing fluid communication between the fluid container and the injection chamber. When a high pressure condition is rapidly created in the injection chamber, a known volume of fluid is momentum imparted to form a known volume of free-flying droplets that eject from the dispensing orifice. Not all fluid in one or both of the ejection chamber and the outlet tube is ejected. A suck back state is then created, creating a space between the injection chamber and the dispensing orifice. Thereafter, the fluid inflow channel is opened so that fluid from the fluid container can flow into the ejection chamber and fill a portion of the space.

  There is also provided a method for injecting a small amount of viscous fluid, wherein a precisely metered fluid flows into the injection chamber. It is advantageous if the fluid metering is adjusted manually or programmatically to obtain the desired refill volume of fluid. In this method, an active metering device is preferably used to flow a predetermined amount of viscous fluid from the fluid container through the inflow channel into the injection chamber. When the desired amount of fluid flows into the ejection chamber, the fluid inflow channel is closed and fluid communication between the fluid container and the ejection chamber is reduced. When a high pressure condition is rapidly created in the injection chamber, the fluid is momentum and a free-flying droplet of known volume is formed and ejects from the dispensing orifice. A suck back state is then created, creating a space between the injection chamber and the dispensing orifice. Thereafter, the fluid inflow channel is opened, allowing fluid from the active metering device to enter the ejection chamber.

The structure, operation and advantages of the presently preferred embodiments of the present invention will become more apparent upon consideration of the following description in conjunction with the accompanying drawings. In the drawings, the same parts are denoted by the same reference numerals.
FIG. 4 is a side cross-sectional view of the injection chamber assembly with the elastic diaphragm fully deflected. FIG. 2 is a side cross-sectional view of the injection chamber assembly of FIG. 1 with the elastic diaphragm deflected to some extent just before the fluid inflow channel is opened. FIG. 2 is a side cross-sectional view of the injection chamber assembly of FIG. 1 with the elastic diaphragm fully relaxed. FIG. 2 is a side cross-sectional view of the injection chamber assembly of FIG. 1 with the elastic diaphragm deflected to some extent when the fluid inflow channel is closed. FIG. 2 is a side cross-sectional view of the injection chamber assembly of FIG. 1 with the elastic diaphragm fully deflected and a viscous fluid droplet injected. FIG. 3 is a side cross-sectional view of an injection chamber assembly with a resilient diaphragm fully deflected by a mechanical forcing element and a viscous fluid droplet injected. FIG. 6 is a side cross-sectional view of the injection chamber assembly showing the volumetric displacement of the diaphragm between the position shown in FIG. 4 and the position shown in FIG. 5. FIG. 3 is a side cross-sectional view of the injection chamber assembly with the undulating elastic diaphragm fully relaxed. FIG. 5 is a side cross-sectional view of another embodiment of an injection chamber with a relief attached to the relief and the elastic diaphragm projecting therethrough completely relaxed. FIG. 3 is a top cross-sectional view of a nozzle plate showing an injection chamber, a fluid inflow channel, an outflow tube, and a dispensing orifice. FIG. 3 is a side cross-sectional view of the injection chamber of FIG. 1 with the elastic diaphragm fully deflected in communication with the two-chamber metering device with the first and second chambers open. FIG. 12 is a side cross-sectional view of the assembly of FIG. 11 having an injection chamber with the elastic diaphragm fully deflected with the first chamber closed and the second chamber open. FIG. 12 is a side cross-sectional view of the assembly of FIG. 11 having an injection chamber with the elastic diaphragm fully relaxed with the first chamber closed and the second chamber open. FIG. 12 is a side cross-sectional view of the assembly of FIG. 11 having an injection chamber with the elastic diaphragm fully relaxed with the first and second chambers closed. FIG. 12 is a side cross-sectional view of the assembly of FIG. 11 having an injection chamber with the elastic diaphragm fully deflected with the first and second chambers closed and a droplet of viscous fluid injected. FIG. 12 is a cross-sectional side view of the assembly of FIG. 11 having an injection chamber with the elastic diaphragm fully deflected with the first and second chambers closed and a drop of viscous fluid injected by the impact element. Injection with the first and second chambers open and the elastic diaphragm in communication with the two-chamber metering device in a state where the volume of the second chamber is gradually reduced by an adjustment element that flexes the diaphragm to some extent FIG. 12 is a side cross-sectional view of yet another embodiment of the assembly of FIG. 11 having a chamber. FIG. 5 is a side cross-sectional view of another embodiment having an injection chamber with a resilient diaphragm in communication with a pressurized vessel having a single chamber valve that initiates / stops fluid flow to the injection chamber assembly. Side surface sectional drawing of the viscous injection apparatus which deflects an elastic diaphragm as shown in FIG.1 and FIG.11 using an air pressure. FIG. 17 is an enlarged side sectional view of a part of the viscous injection device shown in FIG. 16, showing an elastic diaphragm, an injection chamber, a metering chamber, an air channel, a fluid inflow channel, and a dispensing orifice. FIG. 18 is an enlarged front cross-sectional view along the AA cross section of FIG. 17. FIG. 18 is an isometric view of the diaphragm showing the extension shown in FIG. 17. The side sectional view of another embodiment of the viscous injection device which deflects an elastic diaphragm using a mechanical piston.

  Hereinafter, the operation will be described first, and the details of the configuration will be described later. FIGS. 1 to 5 show the ejection chamber assembly 10 and a series of steps showing the change in position of the diaphragm when ejecting a small droplet of viscous fluid from the ejection chamber assembly 10. First, FIG. 1 shows an injection chamber assembly 10 for injecting a small amount of viscous fluid. The state of the jet chamber assembly 10 is similar to the state immediately after the viscous fluid droplets are jetted and is the starting state of the method of jetting the viscous material. An elastic diaphragm 24 is provided between the support structure 26 and the nozzle plate 14. High pressure fluid (preferably air) from an external source (not shown) is passed through an air tube 28 formed in the support structure 26 and therefore impinges on the diaphragm 24. Diaphragm 24 bends downward and leans against the side defining the remainder of injection chamber 12.

  The shape of the ejection chamber 12 may be any continuous curve, and is a size that can provide an ejection fluid of a predetermined size. The preferred shape of the chamber 12 is spherical, but a parabolic curve is also considered suitable. Other configurations of the chamber 12 are also considered suitable. The shape of the chamber 12 is preferably selected such that during operation, the diaphragm 24 contacts the sides that make up the rest of the chamber so that all fluid can be ejected from the chamber. Similarly, the diaphragm 24 is preferably constructed and retained by the support structure 26 so that all fluid can be ejected from the chamber 12 at any time, although this is optional. The channel 28 is preferably in the center of the chamber 12 and on a common longitudinal axis with the outflow tube 16 as will be described below.

  A part of the diaphragm 24 preferably enters the outflow pipe 16 provided in the nozzle plate 14, but this is optional. Dispensing needle 20 projects from nozzle plate 14 having an outflow tube 16 in fluid communication with dispensing orifice 18 at its tip. The dispensing orifice 18 is shown as an opening in the disk 19 that closes a part of the needle 20 and is smaller than the inner diameter of the needle 20, but includes the opening end of the needle without using the disk 19. Also good. A fluid inflow channel 22 provided in the nozzle plate 14 communicates with the injection chamber 12 and is blocked by deformation of the diaphragm 24 during operation of the assembly 10. The channel 22 is conveniently formed on the surface of the nozzle plate 14 and the diaphragm constitutes the upper wall of the channel 22. Fluid is confined between the ejection chamber 12 and the outlet tube 16. This prevents the flow of fluid from the fluid container (not shown) into the injection chamber 12 via the inflow channel 22.

  The diaphragm 24 is preferably made of an elastomer material that returns to a state before deformation (preferably a planar shape) when no strain load or deformation load is applied. As shown in FIG. 2, when the diaphragm 24 starts to return to the position before the deformation, the high-pressure air that deforms the diaphragm 24 is discharged from the air pipe 28 formed in the support structure 26. In FIG. 2, the diaphragm 24 is separated from the side surface of the injection chamber 12 and is in a bent position immediately before the fluid inflow channel 22 starts to open. The fluid contained in the outflow pipe 16 is separated from the dispensing orifice 18, and a space 30 a is formed between the disk 19 and the remaining fluid. The volume of the space 30a is equivalent to the displacement volume of the diaphragm 24 between the states shown in FIGS. The speed at which the diaphragm 24 moves away from the injection chamber 12 can be important for thin fluids or fluids including dissolved air. If the deflection is too fast, ambient air may be taken into the fluid. That is, it may promote air dissolution, which is undesirable. The fluid may be degassed to keep the possibility of air uptake low. Alternatively, the speed of the diaphragm 24 may be suppressed by limiting the discharge speed of the high-pressure air. Various methods are conceivable as methods for suppressing the movement speed of the diaphragm, such as changing the size of the tube 28, changing the thickness and material of the diaphragm 24, and changing the shape and size of the injection chamber 12.

  As shown in FIG. 3, when the high-pressure air is completely exhausted, the diaphragm 24 can return to the fully relaxed position before the deformation. And if the diaphragm 24 returns to the position before the deformation | transformation, the space 30b will become large. Further, the fluid inflow channel 22 is opened, and the fluid can flow into the ejection chamber 12. Filling the injection chamber 12 is often referred to as a refill cycle and plays a very important role in the injection process. Since the volume of the fluid flowing into the ejection chamber 12 can be gradually adjusted, a plurality of ejection droplet volumes are generated. Preferably, the amount of fluid does not exceed the volume of the space 30b. In some cases, a fluid can be supplied to the ejection chamber 12 using a pressurized fluid container (not shown). In this case, the fluid flow rate is determined by the pressure level of the fluid container (not shown), the fluid flow characteristics, and the injection chamber assembly 10. The actual amount of fluid flowing into the ejection chamber 12 may be proportional to the fluid flow rate and flowable time. In some cases, fluid may be supplied to the injection chamber 12 using an active metering pump (not shown) such as a syringe pump, gear pump, Auger pump, or peristaltic pump. In this case, the active metering pump supplies the injection chamber 12 with an exact predetermined amount of fluid that does not vary with time. In any case, the volume of the space 30b is equivalent to the displacement volume of the diaphragm 24 between the states of FIGS. 1 and 3 minus the volume of the fluid that can flow into the injection chamber 12. Channel 22 is more convenient if it is approximately 25-70% of the depth of the chamber, and is preferably approximately 50% or less. A vacuum is not considered necessary to repeatedly return the diaphragm to its relaxed position prior to its deformation. This simplifies the design and eliminates the need to evacuate the air channels 28, 52, 54. However, if desired, a vacuum may be utilized to pull the diaphragm 24 back from one or more chambers.

  As shown in FIG. 4, when high pressure air is passed through the air tube 28, the diaphragm 24 begins to deflect into the injection chamber 12. Diaphragm 24 is in a flexed position immediately after fluid inflow channel 22 is closed. In this state, fluid is confined in the ejection chamber 12 and the outflow pipe 16. The volume of the space 30c is reduced by the volume displacement of the diaphragm 24 between the states of FIGS.

  As shown in FIG. 5, when high-pressure air is passed through the air tube 28, the diaphragm 24 bends downward, rapidly creating a high-pressure state and imparting sufficient momentum to the fluid, resulting in a viscous fluid droplet. 32 pops out of the orifice. In particular, a high momentum transmission is desirable for viscous fluid injection. The bending speed of the diaphragm 24 is determined by the driving force to be applied, and determines the size and shape of the high-pressure state, and hence the outlet speed and shape of the ejected droplet. There are several methods for applying the driving force to the diaphragm 24. In the case of FIGS. 1 to 5, the driving force is high-pressure air that passes through the air pipe 28 and reaches the diaphragm 24. The speed of the diaphragm depends on the height of the air pressure and the area of the diaphragm. Since the height of the air pressure can be limited by the availability of the air pressure supply source, the speed of the diaphragm is also limited. When it is desired to increase the bending speed, an impact component can be added to the driving force. Referring to FIG. 6, the injection assembly 33 includes a mechanical impact element 34 that impacts the diaphragm 24, and the deflection speed of the diaphragm 24 is greatly improved. For example, the impact element 34 may be a pneumatic cylinder or an electric solenoid rod end. Alternatively, a rod connected to a controllable exercise device such as a movable electric coil may be used as a driving force that gives an impact to the diaphragm 24. The use of a controllable driving force is advantageous in that the speed and / or acceleration of the impact element 34 when impacting the diaphragm 24 can be controlled. By controlling the movement of the impact element, it is also possible to control the outlet velocity and shape of the droplet, so that a wide range of fluids can be used and the quality control of the droplet can be improved. Other impact means may be used. Alternatively, the impact element 34 may be included in the support structure 26 to apply an impact from the outside.

  FIG. 7 shows a volume displacement 36 equivalent to the volume displacement of the diaphragm 24 between the states shown in FIGS. 4 and 5. Since the diaphragm 24 coincides with the side of the injection chamber 12, the volume displacement is known and reproducible. The diaphragm 24 can be displaced into the outflow pipe 16 by a further minute volume according to its rigidity, and the total displacement volume increases. Diaphragm 24 is displaced by a known and reproducible volume, which can also be described as an active displacement volume. The active displacement volume rapidly creates a high pressure state and imparts the required momentum to the fluid, causing the viscous droplet 32 to fly out of the orifice 18 and fly to the substrate. This active displacement volume is not necessarily equal to the volume of the viscous fluid droplet 32, but is a common volume for a given combination of both inflow and diaphragm deformation. Conveniently, the volume of the fluid droplet 32 is less than the volume of the jet chamber 12 measured between the bottom surface of the inflow channel 22 and the side or wall surface of the chamber 12 and the junction of the outflow tube 16.

  The diaphragm 24 needs to be made of an elastic material so that it can easily coincide with the side surface of the injection chamber 12. Elastomeric materials such as silicon and neoprene are considered suitable for the material selection of the diaphragm 24. A diaphragm 24 with a durometer of Shore 50-90A is considered suitable. The material of the diaphragm 24 needs to be chemically symbiotic with the fluid to be jetted. Some fluids may adversely affect the material of the diaphragm 24, which may shorten the life of the diaphragm 24. As shown in FIGS. 1-7, the diaphragm 24 is a flat element.

  Diaphragm 24 need not be flat and may be convenient if the details are curved. FIG. 8 shows a diaphragm 38 in which a small hemispherical portion 35 is provided at the center of the injection chamber 12. The hemispherical portion 35 is conveniently molded integrally with the diaphragm 38 and extends from the remaining portion of the diaphragm. The hemispherical part 35 enters the injection chamber 12 and reduces its volume. This reduction in volume by the hemisphere 35 reduces the space 30 when the diaphragm returns to its relaxed state. Smaller space 30 is preferred when a very small volume of viscous droplets 32 is desired. The hemispherical portion 35 of the diaphragm 38 is merely an example of a curved shape, and a dome shape, a conical shape, a truncated cone shape, or the like may be integrally formed as a part of the diaphragm 38.

  Alternatively, as shown in FIG. 9, the diaphragm 24 may include an outer part made of elastomer and a harder or higher rigidity inner insertion part 40 by having an insertion part 40 made of another material. Good. For example, the insertion portion 40 may be a metal or hard plastic with a dome portion or hemisphere portion protruding into the injection chamber 12. Further, as shown in FIG. 9, the insertion portion 40 may optionally have an extended flange 41 fixed, bonded, thermally coupled, molded, or fastened to the facing surface of the diaphragm 24. The fastening method or mechanism differs depending on the material of the diaphragm 24 and the insertion portion 40. The insertion portion 40 is preferably at the center of the needle 20 and has a longitudinal axis that is in line with the longitudinal axis of the needle 20 and the dispensing orifice 18, and the longitudinal axis passes through the center of the injection chamber 12.

  When the diaphragms 24 and 40 made of two kinds of materials are fully bent, the rigid insert 40 gives an impact to the side surface of the injection chamber 12 without receiving a damping effect by the elastomer material constituting the remaining part of the diaphragm 24. . Therefore, the transmission efficiency of the momentum from the hard insertion part 40 becomes high. If the insert 40 has a shape that extends through the support structure 26 on the opposite side of the dispensing orifice 18, the mechanical element 34 can be easily attached to the insert 40 to deflect the diaphragm 24 with bi-directional forces. Good. The use of the hard insertion portion 40 for the diaphragm 24 is preferable when high impact efficiency is required. Alternatively, if the adhesive fluid tends to limit the relaxation rate of the elastomeric diaphragm 24, it may be preferable to bend with a bi-directional force. The insert 40 is preferably at least 5 to 10 times as hard as the rest of the diaphragm 24 that extends into the chamber 12.

  FIG. 10 shows a top view of the nozzle plate 14. Only a part of the fluid inflow channel 22 enters the injection chamber 12 and is not connected to the outflow pipe 16. As a result, the diaphragm 24 is deformed into the injection chamber 12 and the fluid communication between the channel 22 and the injection chamber 12 can be blocked. When the inflow channel 22 extends to the entire depth of the injection chamber 12, the diaphragm 24 cannot prevent the backflow from the chamber 12 to the channel 22. Therefore, the portion of the channel 22 that becomes the interface with the injection chamber 12 is preferably shallower than the depth of the chamber 12. The relative sizes of the channel 22 and the chamber 12 depend on the viscosity of the fluid and the size of the ejected droplet 32. For most applications in which a thin viscous fluid microdroplet 32 is ejected, a channel 22 of around 100-200 μm is considered suitable. In this case, the channel 22 advantageously extends to less than about half the depth of the chamber as measured between the flat diaphragm 24 and the curved bottom surface of the injection chamber 12 in the outlet tube 16. Further, the inflow channel 22 may be curved in the length direction with the deep side arranged outside the injection chamber interface to reduce the flow resistance in the case of a dense fluid.

  FIGS. 11-15 show an injection chamber assembly 10 in fluid communication with a two-chamber metering device 80 that uses the two-chamber metering device 80 to fill the injection chamber assembly 10 and cause the jet chamber assembly 10 to cause a viscous fluid. A series of steps of the method of ejecting a microdroplet 32 is shown. The two-chamber metering device 80 includes a flexible elastic diaphragm 42 provided between the support structure 56 and the metering plate 44. As the high pressure fluid (preferably air) passes through the fluid tubes 52, 54 of the support structure 56, the diaphragm 42 is locally deformed into a corresponding fluid chamber provided directly below the diaphragm 42. A first fluid chamber 48 and a second fluid chamber 46 connected by a fluid flow channel 50 are provided on the surface of the metering plate 44, and the fluid pipe 52 connects the diaphragm 42 to the second fluid chamber 46. The fluid tube 54 deforms the diaphragm 42 into the first fluid chamber 48. The first chamber 48 may be considered a container chamber and the second chamber 46 may be considered a metering chamber. The volume of the first container chamber 48 is conveniently larger than the volume of the second metering chamber 46 and is preferably larger than the volume of the injection chamber 12. It is advantageous if the volume of the second metering chamber 46 is equal to or slightly larger than the volume ejected from the chamber 12 as the jetted droplet 32 of viscous fluid. The first fluid chamber 48 may have a closed bottom surface opposite the top surface of the opening or may have a channel in fluid communication with the bottom surface. The second fluid chamber or metering chamber 46 preferably has a closed bottom surface opposite the open top surface.

  The interface of the fluid flow channel 50 at the edge of the first fluid chamber 48 and the edge of the second fluid chamber 46 prevents the flow through the corresponding chamber when the diaphragm 42 is displaced into each chamber. , Preferably designed to be occluded. Here, since the interaction and design of the inflow channel 22 and the injection chamber 12 of the diaphragm 24 described above also apply to the diaphragm 42, the flow channel 50, and the chambers 46 and 48, the description thereof will not be repeated. However, if the channel 50 is in fluid communication with the bottom surface of the first container chamber 48, the diaphragm extends into the chamber sufficient to occlude fluid flow from the channel 50 to the chamber 48. Is preferred. As shown, the assembly 10 and the two-chamber metering device 80 are separate structures. There is a diaphragm 42 in the two-chamber metering device 80 and a diaphragm 24 in the injection chamber assembly 10. Here, if a single shared structure in which the diaphragms 24 and 42, the support structures 26 and 56, and the nozzle plate 14 and the measuring plate 44 are the same parts is adopted, the apparatus can be simplified and the cost can be reduced. I can expect. In this case, it is preferable that the same parts are integrally formed of a single material. Similarly, although a single diaphragm 24 is used, a separate seal structure may be employed around each chamber 12, 46, 48.

  FIG. 11 shows the injection chamber assembly 10 in the same state as FIG. A fluid flow channel 50 provided in the two-chamber metering device 80 is in fluid communication with the ejection assembly 10 via the fluid inflow channel 22. Since the diaphragm 42 is in a state before being deformed, fluid from an external fluid container (not shown) connected to the fluid flow pipe 50 is supplied to the first fluid chamber 48, the second fluid chamber 46, and the fluid inflow channel 22. Can flow into. The flow of fluid into the injection chamber 12 is blocked by the deformed diaphragm 24. The fluid is filled in the first fluid chamber 48, the second fluid chamber 46, the fluid flow pipe 50, and the fluid inflow channel 22, and is also contained in the fluid outflow pipe 16.

  FIG. 12 shows the injection chamber assembly 10 in the same state as FIG. A fluid flow channel 50 provided in the two-chamber metering device 80 is in fluid communication with the ejection assembly 10 via the fluid inflow channel 22. Air from an external pressure supply (not shown) causes high pressure air to pass through the fluid line 54 and the diaphragm 42 to be deflected into the first fluid chamber 48 so that the fluid from the first fluid chamber 48 is fluidized. Back flow toward the container (not shown). Here, since the diaphragm 24 blocks the flow channel 22, the fluid cannot flow into the ejection chamber 12, and the flow to the first fluid chamber 48 through the channel 50 is also blocked, so that the second fluid The fluid in the chamber 46 is blocked from flowing into the ejection chamber 12 and the first fluid chamber 48.

  Referring to FIG. 13, the state of the two-chamber metering device 80 is the same as the state of FIG. However, since the high-pressure air that has deformed the diaphragm 24 is removed, the diaphragm 24 is retracted to the state before the deformation, and a space 30 is formed. The state of the injection chamber 12 is the same as the state of FIG. Since the fluid inflow channel 22 is open, the ejection chamber 12 receives fluid from the two-chamber metering device 80.

  Referring to FIG. 14, the state of the injection chamber assembly 10 is the same as that of FIG. 13, but when high pressure air is passed through the fluid tube 52, the diaphragm 42 bends into the second fluid chamber 46. As a result, the fluid flows into the ejection chamber 12 and the space 30 changes. The space 30 is reduced by exactly the same amount as the fluid displaced from the second fluid chamber 46. The volume of ejected droplets is directly related to the volume of fluid that has been moved or metered into space. If the volume of the second fluid chamber 46 can be gradually adjusted, it is convenient to provide a predetermined volume of ejected droplets.

  Referring to FIG. 15a, the state of the two-chamber metering device 80 is the same as the state of FIG. The diaphragm 24 is deformed by the high-pressure air, a high-pressure state is rapidly generated, and the viscous fluid droplet 32 is ejected. When the cycle is repeated, the high-pressure air in the fluid pipes 52 and 54 is discharged, and the state of the two-chamber metering device 80 is exactly the same as the state of FIG. The two chambers 48, 46 provide a metering pump or metering means for supplying a predetermined amount of fluid to the ejection chamber 12. Further, the diaphragm 42 deflected into the second chamber 46 as shown in FIG. 15 occludes the flow of fluid through the channel 22 toward the container, and the accuracy of the volume of the ejected fluid 32 during ejection and Provides a means to improve invariance. A diaphragm 42 deflected into the first chamber 48 as shown in FIG. 15 provides another means of blocking the flow of fluid through the channel 22 toward the container.

  FIG. 15 b shows another configuration in which the operation of fluid inflow and outflow to the chambers 46, 48 is not limited to the fluid deformation of the diaphragm 42. As with the impact element 34, the mechanical impact elements 64, 66 may optionally be configured and operated. The state of the two-chamber metering device 80 is the same as the state of FIG. 14 except that the high pressure air is replaced by the impact elements 64 and 66. The impact elements 64, 66 deflect the diaphragm 42 into the fluid chambers 46, 48, respectively. The impact element 34 deflects the diaphragm 24 to rapidly create a high pressure condition and ejects a viscous fluid droplet 32. When the cycle is repeated, the impact elements 64, 66 are retracted and the state of the two-chamber metering device 80 is exactly the same as in FIG.

  In FIG. 16a, a two-chamber metering device 80 and an injection chamber assembly 10 are shown. The mechanical adjustment element 60 impinges directly on the diaphragm 42 on the second fluid chamber 46 and adjusts the volume of the second fluid chamber 46. The adjustment element 60 is not for deflecting the diaphragm 42 into the second fluid chamber 46 to flow the fluid into the injection chamber 12, but in the step shown in FIG. 14, the volume of the fluid flowing into the injection chamber 12 is gradually increased. Can be changed to The position of the adjustment element 60 can be adjusted manually, and the volume of the second fluid chamber and thus the volume of fluid flowing into the space changes. The alignment of the adjustment element 60 is preferably done manually as described above so that the volume of the second chamber can be increased or decreased during adjustment. Alternatively, the adjustment element 60 may be attached to a controllable device (not shown) such as a motor so that the position of the adjustment element can be changed by a program to provide a predetermined volume. It is also convenient if the error state can be determined by measuring the size or volume of the ejected droplet with respect to a predetermined size or volume using a measuring device (not shown). If an error condition is measured, the position of the adjustment element 60 may be changed manually or programmatically so that the desired shape or volume of a given droplet can be more precisely ejected.

  FIG. 16 b shows another embodiment with an injection chamber assembly 10 and a pressure refill device 90. A pressurized container 68 is in fluid communication with the inflow channel 50. A diaphragm 42 is provided between the metering member 44 and the support structure 56 so that the fluid 42 can be prevented from flowing into the injection chamber 12 through the inflow tube 22 by bending into the chamber 46. As shown, high pressure air deflects diaphragm 42 through chamber 61 into chamber 46. Alternatively, as shown in FIG. 15a, the diaphragm 42 can be bent by a piston. The injection chamber 10 is in a state where the diaphragm 24 is completely relaxed. The space 30 is available for receiving fluid from the pressurized fluid container. When refilling the injection chamber, high pressure air is exhausted from the air tube 61 and the diaphragm 42 is retracted, so that the inflow channel 50 opens and communicates with the inflow channel 22, allowing fluid to flow into the injection chamber 12. . The amount of fluid that can flow into the injection chamber 12 depends on the flow rate of the fluid flowing through the inflow channel 22 and the opening time of the chamber 46. By changing the opening time of the chamber 46, the amount of refilled fluid can be gradually changed, resulting in both the desired volume and quality of the droplets. As shown, the refill cycle and the injection cycle operate independently. By gradually adjusting the refill volume, the overall injection reliability and quality can be further controlled.

  17 and 18 illustrate one embodiment of a viscous injector 100 that includes a chamber assembly 10 and a two-chamber metering device 80 that share a common diaphragm 24 and a common support structure in the form of an air manifold 108 and nozzle plate 14. Show. By operating the injection device 100, the various steps described above, preferably the series of steps shown in FIGS.

  An air solenoid 110 is attached to the air manifold 108 and is in fluid communication and provides a source of compressed air. Two other air solenoids (not shown) arranged adjacent to each other are also attached to the air manifold 108 in the same manner as the air solenoid 110, and are in fluid communication with the chambers 12, 46, 48, respectively, so that one air solenoid 110 is in the chamber. 12, 46, and 48, respectively. Thus, each chamber 12, 46, 48 will have a dedicated fluid pressure source, preferably in the form of an air solenoid 110. Specifically, the first air solenoid 110 is in fluid communication with the first chamber 48 via the air tube 52, and the second air solenoid 110 is in fluid communication with the second chamber 46 via the air tube 54. A third air solenoid 110 is in fluid communication with the injection chamber 12 via the air tube 28.

  Diaphragm 24 has opposing first and second surfaces, with the second surface contacting the nozzle plate to form a fluid tight seal while contacting the air manifold 108 to form an air tight seal. . Viscous fluids can be sealed at a lower pressure than air. Although a seal ring or a convex seal portion can be employed on both sides, it is convenient for the diaphragm 24 to have a substantially flat second surface and a convex seal portion 124 on the first surface. . Accordingly, the diaphragm 24 is contained between the air manifold 108 and the nozzle plate 14 and has convex portions, ribs or flanges that contact the manifold 108 and form an airtight seal between the fluid tubes 52, 54 and 28 during use. It is convenient to have an extension 124 such as. Diaphragm 24 is compressed against nozzle plate 14 to form channels 22 and 50 by forming a fluid tight seal. The extensions, seals, or ribs 124 are preferably formed or molded integrally on the flexible diaphragm 24 by forming or molding an integral piece with the diaphragm 24.

  Referring to FIGS. 17 and 18b, it is convenient to provide a mechanism for adjusting the clamping force for holding the diaphragm 24 and urging the nozzle plate 14. This mechanism may be in the form of a screw-type adjustment, with a micrometer 102 (FIG. 17) attached to the micrometer mount 104 and in contact with a spring assembly 106 contained between the micrometer mount 104 and the air manifold 108. preferable. In addition, a relative movement that can be adjusted in units of about 125 μm, such as an LVDT, a solenoid, a piezoelectric element, a piezoelectric ratchet, or a gear mechanism, is given, and preferably a small positioning mechanism may be used. Such mechanisms are well known in the art or can be readily developed to meet the described requirements and will not be described in detail herein. Since the micrometer base 104 and the nozzle plate 14 are connected, the spring 106 elastically biases the air manifold 108 toward the nozzle plate 14 to compress the diaphragm 24 against the nozzle plate. The air manifold 108 and the diaphragm 24 are sandwiched between the micrometer mount 104 and the nozzle plate 14. Here, since the nozzle plate is connected to the micrometer mount 104, the spring 106 integrally biases the air manifold 108 and the nozzle plate 14, so that the diaphragm 24 is reliably sealed between the two. One mechanism for this will be described.

  The micrometer mount 104 preferably includes two dowels 144 (one shown in FIG. 18b) that pass freely through the air manifold. Each dowel 144 has one end fixed to the micrometer mount 104 and the other end has a thumbscrew 140 passing through the air manifold 108. Since the nozzle plate 14 is attached to the dowel 144 by the butterfly screw 140, the nozzle plate 14 is connected to the micrometer mount 104 and operates integrally. On the other hand, the manifold 108 is operable relative to the dowel. The butterfly screw 140 can adjust the distance between the gantry 104 and the plate 14 and can be used to fix the distance between the gantry 104 and the plate 14 or can be used to coarsely adjust the distance. . The spring assembly 106 applies an elastic sealing force by the micrometer mount 104 and the manifold 108 via the dowel pin 144. The spring 106 elastically biases the manifold 108 and nozzle plate 14 and compresses the diaphragm 24 with a predetermined load sufficient to ensure a fluid tight (and air tight) seal. The micrometer 102 can be adjusted much more accurately than a screw connection such as a thumbscrew 140 to change the deflection of the spring assembly 106 to adjust the predetermined load applied to the diaphragm 24. When the adjustment is performed, the preload can be locked at an appropriate position of the air manifold 108 via the butterfly screw 142. It is also possible to adjust the volume of the second fluid chamber 46, similar to FIG. 16a, by adding a diaphragm 24 load or restriction that exceeds the minimum required for sealing. Because the formation of a fluid seal using a hermetic diaphragm 24 requires less pressure than the formation of a hermetic seal, the load or throttling of the diaphragm 24 exceeds the minimum necessary to form a hermetic seal (during operation). It is possible to adjust the volume of the second fluid chamber 46 as in FIG. 16a.

  Referring to FIGS. 17 and 18 a, a nozzle assembly 122 is attached to the nozzle plate 14, and a fluid tight seal is formed by compressing an O-ring 130 provided between the nozzle plate 14. Other seals may also be used. A needle 20 including a dispensing orifice 18 is provided with a nozzle assembly 122. The air solenoid 110 deflects the diaphragm 24 directly above the injection chamber 12 by passing high pressure air through the air tube 28. Similarly, an air solenoid (not shown) deflects the diaphragm 24 directly above the first fluid chamber 48 by passing high pressure air through the fluid tube 52. Similarly, an air solenoid (not shown) deflects the diaphragm 24 directly above the second fluid chamber 46 by passing high pressure air through the fluid tube 54. Each air solenoid can be driven independently. Each air solenoid is preferably mounted on an air manifold 108 and connected to a common air supply channel 116 pressurized by a pressure supply such as an air tank having a fluid pressure supply such as a compressor. . Thus, the solenoid 110 meters air from the air supply channel 116 as needed to deform the diaphragms 24, 50 into the various chambers. The actuation of the solenoid may be controlled by a programmable computer, integrated circuit, or other methods now known or later developed.

  The driving of the air solenoid will be described. When the solenoid 110 is driven, high pressure air flows through the air channel 118 that communicates with the air tube 28, deflecting the diaphragm into the injection chamber 12. The fluid pipes 52, 54 have respective air channels corresponding to the air channels 118. When the air solenoid 110 is stopped, the air pressure of the air channel 118 and the air pipe 28 is exhausted from the exhaust channel 120 (FIG. 17) via the solenoid 110. Each air solenoid 110 is connected to an exhaust channel via an air manifold 108 and is preferably connected to a common exhaust channel 120.

  High pressure air (typically 40-100 psi (2.7 atm-6.8 atm)) from a remote source (not shown) is introduced into the air manifold 108 via the air supply channel 116. The fluid to be ejected is supplied from a pressurized fluid container (not shown) and introduced under pressure into a fluid input port 112 (FIG. 17) communicating with a fluid inlet pipe 126 (FIG. 18a). When the air solenoid 110 is stopped, fluid flows from the fluid inlet pipe 126 until it fills the first fluid chamber 48, and is filled from the first fluid chamber 48 to the second fluid chamber 46 via the fluid flow channel 50. Pour until The fluid then flows from the second fluid chamber 46 into the fluid inflow channel 22 and into the ejection chamber 12 and the outflow tube 16. The interface of the fluid flow channel 50 at the edge of the first fluid chamber 48 and at the edge of the second fluid chamber 46 allows each chamber to be moved as the diaphragm 24 is displaced into the various chambers 12, 46, 48. Designed to prevent flow through. The edge of the second fluid chamber 46 and the interface of the fluid inflow channel 22 in the ejection chamber 12 is such that when the diaphragm 24 is displaced into the chambers 12, 46, the flow from the connecting channel 22 through these chambers is prevented. Designed to.

  The nozzle plate 14 is optionally provided with a heating element 114 to locally heat the fluid contained in the nozzle plate 14 and the jet chamber assembly 10 as needed. Further, a heating mechanism may be provided in another place of the apparatus according to the viscosity of the fluid to be ejected.

  FIG. 18 c is an isometric view of the diaphragm 24 with the extension 124 and the flat region 127. As shown in FIG. 18 a, the extension 124 is coupled to the gland 125 and forms an airtight seal around the air tubes 52, 54, 28 when compressed against the air manifold 108. A flat region 127 provided on the opposite side of the extension 124 forms a fluid tight seal around the fluid chambers 48, 46, 12 when compressed against the nozzle plate 14. Conveniently, the extension 124 includes a seal rib or ring that forms a hermetic seal with the support structures 26, 206 on one side of the diaphragm 24 under normal operating conditions. The face of the diaphragm 24 opposite the rib 124 is substantially flat and it is convenient to form a fluid tight seal with the nozzle plate 14 in normal operating conditions. Forming a sufficient hermetic seal on one face of the diaphragm 24 of the diaphragm 24 requires a higher pressure than forming it on the other face, so it is convenient to provide the seal rib 124 only on one face. Depending on the viscosity and properties of the fluid to be dispensed, the position and orientation of the seal ring or seal 124 on the diaphragm 24 may be varied as required.

  FIG. 19 shows another embodiment of a viscous injection device 200 that includes an injection chamber assembly 33 and a two-chamber metering device 80 that share a common diaphragm 24 and a common support structure in the form of an air manifold 206 and a nozzle plate 14. ing. The injection device 200 can execute a series of steps shown in FIGS. 11 to 15 by driving. The two-chamber metering device 80 is similar to that described in connection with FIGS. The injection chamber assembly 33 includes an air manifold 206 and a piston 204 included in a cylinder mount 208. The spring assembly 210 applies an elastic biasing force to the piston 204 so that the piston does not contact the diaphragm 24. In the direction shown in FIG. 18, the spring assembly 210 biases the piston 204 upward. Further, when the air cylinder 202 (a part of which is shown) is driven by high-pressure air, the rod end gives an impact to the piston 204, whereby the piston 204 is accelerated into the diaphragm 24, and as in FIG. A droplet is released. The counterbore surface 203 prevents excessive deflection by the piston 204 that can lead to damage to the diaphragm 24. A suitable amount of deflection by the piston 204 is such that the tip of the piston 204 compresses the diaphragm 24 by 25-50% of its thickness. Since the deflection speed of the diaphragm 24 is increased by the impact of the piston 204, a highly viscous fluid can also be ejected. Various mechanisms, such as solenoids, coils, and various spring / fluid drivers, can be used to drive the piston 204 and the air cylinder 202.

FIG. 19 shows a heating element 114 mounted in a heating block 212 that is attached to the nozzle plate 14 to locally heat the fluid.
Functional and conceptual conditions of basic working parts Viscous injection can be divided into two cycles: injection cycle and refill cycle. The injection cycle as defined herein is a method of rapidly creating a high pressure condition in the fluid contained in the injection chamber assembly. When this rapid high-pressure condition is transmitted to the fluid, a certain volume of fluid passes through the dispensing orifice due to the momentum to move forward, and at a certain outlet velocity, a single droplet jumps out of the dispensing orifice and is non-contacting. "Fly" to the board. The fluid exit velocity is important for producing high quality droplets and depends on the fluid viscosity and momentum transmission. If the amount of momentum transmitted is too small, fluid ejection from the dispensing orifice will be too slow to be separated from the orifice and free-flying droplets will not be formed. Also, if there is a loss in the fluid system, a pressure drop may occur and the transmission of momentum to the fluid may be reduced. Such losses include the generation of bubbles in the injection chamber, the length of the path from the injection chamber to the dispensing orifice, folding or perpendicularity, the elasticity or compressibility of the fluid, or the flow of fluid in the opposite direction of the orifice, etc. Can be the cause. Also, if a very small amount of viscous fluid droplets of less than 50 nl is desired, a very small dispensing orifice is usually required of less than 200 μm. The pressure drop due to the viscous fluid flowing through this small orifice reduces the fluid exit velocity and increases the likelihood that free flying droplets will not be formed. Alternatively, if the momentum is transmitted excessively, the exit velocity of the fluid through the dispensing orifice can become very high and undesirable conditions can occur. If the exit velocity is too high, the fluid will collide with the substrate at high speed, causing the droplets to be crushed and possibly jumping up, degrading quality and forming a tiny satellite-like droplet that surrounds the central droplet. There is a possibility. According to the method and apparatus described above, an injection pressure that is sufficient to form a given droplet and large enough to eject as a droplet, while sufficiently small to avoid splashing on the substrate is stable. Realized.

  The refill cycle herein is the flow of fluid into the jet chamber assembly before or during jetting of droplets. The volume of ejected droplets and the volume of refill must remain unchanged for stable ejection operation. Ideally, the refill volume should be exactly equal to the volume of the ejected droplets. If the refill volume is smaller than the previous ejected droplet volume, the next ejected droplet will be smaller, and a stable droplet will not be obtained, resulting in reduced quality. If this “insufficiency” of the refill volume continues, there will be insufficient fluid for jetting and eventually no droplets can be generated. On the other hand, if the refill volume is larger than the previous ejected droplet volume, the next droplet becomes large, a stable droplet cannot be obtained, and the quality deteriorates. In the case of an “overfill” of the injection chamber, fluid may flow out of the orifice prior to injection, and excess fluid on the dispense orifice will prevent droplet formation. When overfilling occurs, the fluid sticks to the outside of the orifice, forming a large fluid pool and free flying droplets are not formed. Thus, there is a specific range of refill volume that produces a high quality jet. The methods and apparatus described herein that can accurately adjust the refill volume are useful in producing reproducible high quality jet droplets.

  In order to efficiently move the viscous fluid from the remote container to the injection chamber, the fluid needs to be pressurized. A simple pressurized container is often used for supplying fluid to a normally closed injection chamber such as a reciprocating solenoid valve. The injection chamber is refilled simultaneously with the injection cycle. Or if it is pump apparatuses, such as an Auger pump which can supply a fluid as needed, a fluid can be supplied to an injection chamber under pressure independently of an injection cycle. In some cases, the gravitational pressure of the fluid from the elevated container is sufficient. The methods and apparatus disclosed herein disclose a suitable mechanism that employs a pressurized flow to the injection chamber 12 and fills the chamber.

  The diaphragms 24, 42 are thin and flexible enough to extend into the chamber 12 and open and close the channel 22 during filling and injection, respectively, and intermittent cycles of 20-70 cycles / second during injection. It is preferably durable enough to operate over 1 million cycles. The flexibility of the diaphragms 24, 42, the shape of the chambers 12, 46, 48, and the location of the channels 22, 50 are preferably selected so that each diaphragm closes the channels 22, 50 during operation. Further, the diaphragm 24 injects a predetermined volume from the orifice 18 by extending a predetermined distance beyond the channel 22 toward the outflow pipe 16 during the injection. Conveniently, the diaphragm 42 contacts the side forming the chamber 12 from the channel 22 to the outlet pipe 16 during the injection step. The channel 22 is positioned relative to the chamber 12 such that a predetermined volume to be sprayed is positioned between the adjacent edge of the channel 22 and the junction of the chamber 12 and the outflow tube 16. Further, it is preferable to provide a seal portion such as a rib 124 useful for forming an airtight seal between the manifold 108 and the nozzle plate 14 on the upper surface of the diaphragm 24.

  The outflow tube 16 is preferably cylindrical and is preferably large enough to accommodate a jetted volume of viscous material while maintaining a stable and accurate jetted droplet 32. It is also convenient for the outflow tube 16 to have no sharp edges or cuts, be in the center of the injection chamber 12, provide a straight path, and minimize flow resistance during injection. Furthermore, for the same reason, it is preferable to be in line with the longitudinal axis of the air tube 28. The length of the outflow tube 16 depends on the diameter, and both are selected to be equal to the volume of the injection chamber 12 at a minimum. This prevents the space 30 from entering the injection chamber 12 even at the maximum volume. The volume of the outflow tube 16 is preferably sized to include more than 150% of the volume of the injection chamber 12. The outflow tube 16 may also be included in a removable nozzle assembly 122 with an needle 20, an orifice 18 in the disk 19, and an O-ring seal 130 that contacts the nozzle plate 14, thereby allowing air to flow. A fluid tight seal is provided while contributing to alignment of the needle 20 and the injection chamber 12 with a minimum of cuts and blind spots that confine and reduce efficiency during injection. Alternatively, the interface between the nozzle plate 14 and the nozzle assembly 122 can be eliminated by manufacturing the injection chamber 12, the outflow tube 16, the needle 20, and the orifice 18 as a single piece so as to be disposable. Various nozzle assemblies are known, and the injection mechanisms, pumps, and processes described above can be used with various nozzle assemblies and orifice designs.

  The position of the inflow channel 22 in the injection chamber 12 is determined relative to the outflow tube 16 such that the volume displacement 36 is large enough to rapidly create a high pressure condition, the volume displacement 36 being at least the volume of the injection chamber. It is preferable to arrange so as to be 5%. The inflow channels 22, 50 do not have sharp edges that deform or cut the diaphragms 24, 42, and are in the path of the channels 22, 50 that can act as an air confinement or nucleation site for dissolved air in the fluid. It is formed so that the cut along the line is minimized.

  The air tube 28 is preferably in the center of the injection chamber and is large enough to allow high pressure air to flow efficiently and impinge on the diaphragm 24, but the diaphragm 24 substantially enters the air tube 28 during a refill cycle. It is small enough that it cannot flex. Moreover, it is preferable that it is the magnitude | size below the diameter of the outflow tube 16. FIG. The fluid pipes 52 and 54 have the same configuration, but it is not necessary to limit the diameter of the outflow pipe 16.

  When injecting a substantially dense fluid incorporating dissolved air, the exhaust channel 120 in communication with the air channel 118 and the air tube 28 limits the pressure reduction rate of the injection chamber during the refill cycle by reducing the fluid flow. It is convenient if the space 30 can be formed at a sufficiently low speed so as not to trap or promote air from the air. When injecting a substantially dense fluid, i.e. a fluid that has not taken up dissolved air, it is preferable to allow the decompression chamber 120 to be rapidly depressurized by increasing the exhaust channel 120 and connected to a vacuum source to increase the depressurization rate. It would be advantageous to be able to speed up the refill cycle by substantially improving. Alternatively, when a dense fluid is ejected, a diaphragm having an insertion portion attached to a forcing element may be used so that the diaphragm can be driven in both directions so that refilling can be speeded up. The channels associated with the chambers 46, 48 have a similar or similar configuration and design concept.

  Since the injection chamber 12 does not require detailed mechanical structure to support moving mechanical elements that require a dynamic fluid seal within the chamber, the overall complexity of the injection chamber assembly 10 is greatly reduced, resulting in a total manufacturing cost. Is reduced and efficient cleaning becomes possible. Furthermore, the injection chamber assembly 10 can be made of plastic so as to be disposable and does not require cleaning.

  Micrometer 102 located within micrometer mount 104 is centered on the plane of diaphragm 24 or perpendicular to the plane and creates a compressive load on diaphragm 24 by deflecting spring assembly 106. It is preferable to do this. The diaphragm 24 forms an airtight seal with the manifold 108 and a fluid tight seal with the nozzle plate 14. By adding a diaphragm load above the minimum required for sealing, the volume of the second fluid chamber 46 can be adjusted to gradually adjust the refill volume. Thereby, the volume and quality of the ejected droplet can be changed. The compression load is conveniently locked in place so that it does not change during droplet ejection. The compression of the spring 106 that can be adjusted by the micrometer 102 makes it possible to finely adjust the sealing force applied to the diaphragm 24 (and 42), which helps stabilize a small amount of the jet fluid 32. This adjustable spring compression load is advantageous to improve assembly robustness if it can tolerate variations in the thickness, hardness, or material of the diaphragm 24 that occur in normal manufacturing processes.

  The basic injection assembly includes a nozzle plate 14 containing one or more small chambers 12, 46, 48, an air manifold 26, 108 with air channels leading to corresponding positions in the chamber, and sandwiched between the plate 14 and the manifold. And flexible diaphragms 24 and 42. The nozzle plate and associated nozzle assembly 122 are easily replaceable, as is the diaphragm. Thus, since exchange is easy, it becomes easy to change a jet fluid as needed for biological use, and to avoid contamination. It also makes it easier to replace the nozzle as needed for a viscous material that degrades faster than it can easily clog or wear out the needle. The volume of fluid contained in chambers 12, 46, 48, fluid tubes 22, 50, and outflow tube 16 is substantially small, minimizing the loss of expensive fluids used in biological applications. Can do.

  The above description is only an example, and the present invention is not limited to this. Based on the above disclosure, those skilled in the art will devise various modifications within the spirit and scope of the present invention disclosed herein, such as various modifications of the diaphragms 24, 42 and various designs of the nozzle assembly 122. Is possible. Further, various features according to the embodiments disclosed herein may be used alone or in various combinations and are not limited to the specific combinations described herein. Therefore, the scope of the claims is not limited by the above embodiment.

Claims (35)

In a device that rapidly dispenses a small amount of highly viscous material from an injection needle when the injection mechanism is driven,
The second surface having first and second surfaces opposed to each other, wherein the injection chamber is formed on the first surface, and the injection chamber is configured to be connected to the side surface, the upper opening surface, and the needle. A nozzle plate having a bottom surface having an opening in fluid communication with an outlet on the surface, the nozzle plate having an inflow channel formed in the first surface and in fluid communication with the injection chamber, wherein the inflow channel of the injection chamber A nozzle plate that has entered the side but does not extend to the opening in the bottom of the injection chamber;
A flexible diaphragm that deforms into the injection chamber a sufficient distance to occlude the inflow channel and that is soft enough to provide a fluid seal on the upper surface of the injection chamber, and the nozzle plate. Provided to compress the diaphragm between itself and the nozzle plate, and has an opening aligned with the upper surface of the injection chamber, and the opening mechanism is sufficiently communicated with the injection mechanism. A support structure in which the diaphragm on the top surface of the injection chamber is deformable when driven;
A mechanism for providing a fluid seal on the upper surface of the ejection chamber by holding the diaphragm and the nozzle plate together with sufficient force. The inflow channel is formed in the first surface, and the mechanism provides a fluid tight seal with the inflow channel during use and an airtight seal with the support structure during use. apparatus. A metering chamber formed on the first surface, having an open top surface facing the side surface and the closed bottom surface, and wherein the inflow channel is in fluid communication;
A first channel that fluidly communicates a container chamber with a fluid container, the flexible diaphragm extending over the inflow channel and the metering chamber, a distance sufficient to occlude the inflow channel in the metering chamber The apparatus of claim 1, further comprising a metering device comprising a first channel that is sufficiently flexible to deform into the metering chamber. A container chamber formed on the first surface and having an open top surface facing the side surface and the bottom surface, the container chamber configured to be in fluid communication with a source of high viscosity material dispensed by the device;
A metering chamber formed on the first surface, having an open top surface facing the side surface and the closed bottom surface, and wherein the inflow channel is in fluid communication;
A first channel formed in the first surface and in fluid communication between the container chamber and the metering chamber, the first channel in fluid communication with the container chamber and the metering chamber;
The flexible diaphragm extending over the first channel, the inflow channel, the metering chamber, and the container chamber, wherein the metering chamber closes the inflow channel, and the metering chamber and the container A two-chamber metering comprising a diaphragm flexible enough to deform into the metering chamber and the container chamber a distance sufficient to occlude the first and second ends of the first channel in the chamber The apparatus of claim 1, further comprising an apparatus. 4. The apparatus of claim 3, wherein the diaphragm flexibility and the width of the inflow channel are selected such that the diaphragm extends into the inflow channel during use. The apparatus of claim 3, further comprising a metering protrusion biased by the diaphragm to change a volume between the diaphragm and a bottom surface of the metering chamber. The injection mechanism generates a force that sufficiently deforms the diaphragm to contact a side surface of the injection chamber between the inflow channel and the bottom surface of the injection chamber in fluid communication with the outlet. The device described. The apparatus of claim 1, wherein the injection mechanism generates a force that sufficiently deforms the diaphragm to push the diaphragm into a portion of the outlet at a junction of the outlet and the bottom surface of the injection chamber. The apparatus of claim 1, wherein the diaphragm has a hardened insert located on the injection chamber when the diaphragm is in a relaxed configuration. The apparatus according to claim 1, wherein the diaphragm has a thickening protrusion provided on the injection chamber and partially extending when the diaphragm is in a non-injection configuration during use. 2. The injection mechanism according to claim 1, wherein the injection mechanism includes a solid protrusion that impacts the diaphragm on the injection chamber and pushes the diaphragm into the injection chamber such that the diaphragm contacts the side surface of the injection chamber. Equipment. The apparatus according to claim 1, further comprising a position adjusting mechanism that is disposed between the nozzle plate and the support structure to move the nozzle plate and the support structure relative to each other and change compression of the diaphragm. The apparatus of claim 12, wherein the adjustment mechanism comprises a rotating screw member that varies the amount of relative motion. The injection needle in fluid communication with the outlet of the injection chamber and having a volume greater than the volume of the injection chamber measured between the bottom surface of the inflow channel and the intersection of the outlet and the injection chamber; The apparatus of claim 1. A nozzle plate for use in an apparatus for injecting a highly viscous fluid, the apparatus including an injection mechanism and an injection needle for injecting a highly viscous material during use, and a connection end configured to be connected to the nozzle plate. A nozzle plate having a longitudinal axis of the needle,
A first side and a second side opposite to each other, wherein a jet chamber is formed on the first side, and the jet chamber includes a side surface that surrounds the longitudinal axis during use, an opening top surface, and a bottom surface facing the top surface. An opening, wherein the bottom opening is in fluid communication with the outlet opening on the second surface and is configured to receive the connecting end of the needle during use, the outlet being disposed longitudinally of the injection chamber during use. A plate having a longitudinal axis substantially in line with the shaft, the first surface having an inflow channel in fluid communication with the ejection chamber, the inflow channel entering a side surface of the ejection chamber However, it does not extend to the continuous contact between the chamber side surface and the outlet, and a part of the injection chamber defines a minimum injectable volume, and the part is the bottom surface of the inflow channel, the side surface, and the outlet. Is provided between the coupling point, a nozzle plate having a plate the injectable volume of less than about 1 [mu] l. The nozzle plate according to claim 15, further comprising a metering chamber formed on the first surface and having an open top surface facing the side surface and the closed bottom surface, and the inflow channel is in fluid communication. A container chamber formed on a first surface of the plate, having an open top surface and a bottom surface and in fluid communication with the metering chamber via a first channel formed in the first surface of the plate; A container chamber having a tip that is in fluid communication with a second channel formed in the plate and in fluid communication with a fluid container during use, the container chamber having a volume greater than the volume of the injection chamber; The nozzle plate according to claim 16, further comprising: In a nozzle plate subassembly for use in a high viscosity injection device having an injection mechanism and an injection needle having a longitudinal axis and an outlet for injecting high viscosity material during use.
The injection chamber is formed on the first surface, and has a side surface, an upper surface of the opening, and an opening on the bottom surface facing the upper surface, and the bottom surface opening is the second surface. And in fluid communication with the injection needle during use, the outlet being substantially in line with the longitudinal axis of the injection needle during use and the first A nozzle plate having a longitudinal axis substantially perpendicular to the surface of the nozzle, the nozzle plate having an inflow channel in fluid communication with the injection chamber in the first surface, the inflow channel being in the injection chamber. Nozzle plate which has entered the side surface but does not extend to the continuous contact point between the side surface of the chamber and the outlet, and a part of the injection chamber defines an injectable volume of the material to about 1 μl or less. And,
A metering chamber formed on the first surface, having an open top surface facing the side surface and the closed bottom surface, and having a volume of about 1 μl or less, wherein the inflow channel is in fluid communication;
A flexible diaphragm large enough to fit over the first surface to cover the injection chamber, the metering chamber, and the inflow channel, and having opposing first and second surfaces; The second surface is configured to form a fluid tight seal with the jet chamber, the metering chamber, and the inflow channel during use and to form an air tight seal with the contact surface during use Nozzle plate subassembly with diaphragm. The inflow channel to extend when the diaphragm is pressed against the nozzle plate during use to reduce the volume of the inflow channel and the injection chamber during the injection of high viscosity fluid using a subassembly The nozzle subassembly of claim 18, wherein is sized relative to the diaphragm and its material. A container chamber formed on the first surface, having a side surface and a bottom surface facing the upper surface of the opening, and in fluid communication with the metering chamber via a first channel formed on the first surface; A container in fluid communication with a second channel having an inflow end in fluid communication with the exterior of the nozzle plate, the inflow end being in fluid communication with a fluid container during use of the subassembly. The nozzle subassembly of claim 19, further comprising a chamber. The diaphragm covers the container chamber and the first channel and provides a fluid tight seal therewith and extends into the inflow channel and the first channel when the diaphragm is pressed against the nozzle plate during use. 21. The nozzle subassembly of claim 20, wherein the inflow channel and the first channel are sized relative to the diaphragm and its material so as to restrict fluid flow through the channels. 21. The nozzle subassembly of claim 20, wherein the second surface in contact with the nozzle plate is substantially flat and the first surface includes a convex sealing surface. A small amount of high-viscosity material is dispensed from the outlet of the injection needle by an injection mechanism that deforms the diaphragm into the injection chamber having a side, an open top surface covered by a flexible diaphragm, and a bottom outlet in fluid communication with the injection needle. In the way to
Placing the injection needle, the outlet, and the injection chamber on a common longitudinal axis;
Disposing an inflow channel in fluid communication with a side surface of the ejection chamber that does not extend to a communication contact between the chamber side surface and the chamber outlet;
Pushing a highly viscous fluid into the injection chamber via the inflow channel;
A force sufficient to eject a predetermined volume of material as a droplet from the outlet of the needle is sufficient to close the inflow channel and to contact the side of the chamber adjacent to the continuous contact with the outlet. Deforming the flexible diaphragm into the injection chamber relative to a chamber side. The inflow channel is formed on the same surface as the injection chamber and opens on the surface along the length direction of the channel, and the diaphragm is sealed along the length direction of the channel opening. Being biased sufficiently with respect to the length of the channel opening and the top surface of the chamber so as to change the volume of fluid pushed into the ejection chamber through the inflow channel in the pushing step. Item 24. The method according to Item 23. 24. The method of claim 23, wherein the chamber outlet comprises a cylindrical channel, and wherein in the deforming step, the diaphragm is deformed so as to enter the outlet channel beyond the junction of the chamber side and the chamber outlet. . 24. The method of claim 23, further comprising compressing the diaphragm by a predetermined amount to change the volume of the ejected droplet. 24. The method of claim 23, wherein the injection mechanism that deforms the diaphragm comprises compressed air. 24. The method of claim 23, wherein the injection mechanism that deforms the diaphragm includes physically impacting the diaphragm with a solid body that presses the diaphragm against the chamber side. 24. The method of claim 23, wherein the diaphragm contacts a contact point between the inflow channel and the outlet. In a device for jetting highly viscous fluid,
Chamber means for holding the highly viscous fluid;
Inflow channel means for conveying the highly viscous fluid to the chamber means;
By injecting the high viscosity material from the chamber means at a sufficient rate through an injection needle, a droplet of high viscosity fluid having a volume of less than about 250 nl and having a sufficient speed to be injected from the needle. A device comprising: means for forming. 31. The apparatus of claim 30, wherein the ejection means comprises a flexible diaphragm, and further comprises means for compressively compressing the diaphragm to change the volume of the ejected droplets. 32. The apparatus of claim 31, wherein the jetting means further comprises a pneumatic mechanism that deforms the diaphragm into the chamber means. 33. The apparatus of claim 32, wherein the droplet volume is less than approximately 100 nl. 31. The apparatus of claim 30, wherein the jetting means deforms the diaphragm into a portion of an outlet in fluid communication with the chamber means. 33. At least one chamber means for metering a highly viscous fluid that reaches the chamber means via the inlet channel.
The device described in 1.