System and method for sealing microvalves used in injection assemblies

Abstract

This relates to an injection assembly equipped with a microvalve used for industrial marking and coding. [Solution] The microvalve 164 comprises an orifice plate having a first surface, a second surface, and an orifice extending from the first surface to the second surface. The operating beam is positioned spaced apart from the orifice plate. The operating beam 176 comprises a base portion and a cantilever portion. The base portion is located a predetermined distance from the orifice plate. The cantilever portion extends from the base portion such that its overlapping portion overlaps with the orifice. The operating beam is movable between a closed position and an open position. The microvalve 164 also comprises a sealing structure comprising a sealing member positioned in the overlapping portion of the cantilever portion. When the operating beam 176 is in the closed position, the cantilever portion is positioned such that the sealing structure seals the orifice and closes the microvalve 164.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the priority and benefit of U.S. Provisional Application No. 62 / 670,280, filed on May 11, 2018, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present disclosure generally relates to the field of microvalves manufactured using micro - electro - mechanical system (MEMS) technology. More particularly, the present disclosure relates to an injection assembly comprising a microvalve used for industrial marking and coding.

Background Art

[0003] Conventional printing technologies have several drawbacks. For example, continuous inkjet printers have certain defects that are difficult to eliminate. The process of generating droplets from an ink supply can cause the ink to drip in an undesirable direction (e.g., away from the object), which can lead to maintenance requirements. Further, the replenishing fluid is lost over time as a result of evaporation and requires continuous replenishment. Other maintenance costs, such as the repair of the orifice plate due to deterioration, are also required.

Summary of the Invention

[0004] In some embodiments, the microvalve comprises an orifice plate having a first surface and a second surface. The orifice plate comprises an orifice extending from the first surface to the second surface. The microvalve also comprises an operating beam positioned spaced apart from the orifice plate. The operating beam comprises a base portion and a cantilever portion. The base portion is located a predetermined distance from the orifice plate. The cantilever portion extends from the base portion such that its overlapping portion overlaps with the orifice. The operating beam is movable between a closed position and an open position. The microvalve also comprises a sealing structure comprising a sealing member positioned on the overlapping portion of the cantilever portion. When the operating beam is in the closed position, the cantilever portion is positioned such that the sealing structure seals the orifice and closes the microvalve.

[0005] Another embodiment relates to a method for constructing a microelectromechanical system (MEMS) microvalve. The method includes providing an orifice plate having an orifice. The method also includes providing an actuation beam, the actuation beam having a spacer member and a sealing member attached thereto. The method also includes forming a portion of a sealing structure on either the orifice plate or the sealing member. The method also includes, after forming the portion of the sealing structure, attaching the actuation beam to the orifice plate and aligning the sealing member with the orifice plate, so that the sealing structure forms a seal between the orifice and a volume adjacent to the actuation beam in the closed position of the actuation beam.

[0006] Another embodiment relates to an injection assembly. The injection assembly comprises a valve body having an orifice plate with a plurality of orifices extending through it. The injection assembly also comprises a plurality of microvalves. Each of the plurality of microvalves comprises a spacer member positioned on the orifice plate and displacing the corresponding orifice. Each of the plurality of microvalves also comprises an operating beam comprising a base portion positioned on the spacer member and a cantilever portion extending from the base portion toward the corresponding orifice, the overlapping portion of which overlaps with the corresponding orifice. The operating beam is configured to move between a closed position in which the cantilever portion is bent toward the orifice and an open position in which the cantilever portion is bent toward away from the orifice. Each of the plurality of microvalves also comprises a sealing structure comprising a sealing member attached to the overlapping portion and extending toward the corresponding orifice. The injection assembly also comprises a fluid manifold connected to each of the plurality of microvalves, defining a fluid reservoir for each microvalve.

[0007] Some embodiments relate to a microvalve comprising an orifice plate having a first surface and a second surface. The orifice plate comprises an orifice extending from the first surface to the second surface. An operating beam is positioned spaced apart from the orifice plate. The operating beam comprises a base portion and a cantilever portion, the base portion being a predetermined distance from the orifice plate, and the cantilever portion extending from the base portion toward the orifice, with the overlapping portion overlapping the orifice. The operating beam is movable between a closed position and an open position. A sealing structure is positioned on the operating beam. The sealing structure comprises a sealing member positioned on the overlapping portion of the cantilever portion. A stopper is positioned on the surface of the sealing member. The stopper comprises a first portion attached to the surface of the sealing member and a second portion positioned on the first portion in close proximity to the orifice plate. The second portion has a larger cross-sectional area than the first portion. When the operating beam is in the closed position, the cantilever portion is positioned so that the stopper seals the orifice and closes the microvalve.

[0008] Another embodiment relates to a microvalve comprising an orifice plate having a first surface and a second surface. The orifice plate comprises an orifice extending from the first surface to the second surface. An operating beam is positioned spaced apart from the orifice plate. The operating beam comprises a base portion and a cantilever portion. The base portion is located a predetermined distance from the orifice plate. The cantilever portion extends from the base portion toward the orifice such that its overlapping portion overlaps with the orifice. The operating beam is movable between a closed position and an open position. A sealing structure is positioned on the operating beam. The sealing structure comprises a valve seat surrounding the orifice. The valve seat defines an opening that surrounds the orifice and defines a fluid outlet. The sealing structure is positioned on the overlapping portion of the cantilever portion. A first sealing blade extends the distance of the sealing member from the sealing member surface toward the orifice plate. The first sealing blade surrounds the entire perimeter of the orifice. The sealing blade is configured to contact the valve seat in the closed position in order to seal the fluid outlet and close the microvalve.

[0009] Another embodiment relates to a microvalve comprising an orifice plate having a first surface and a second surface. The orifice plate comprises an orifice extending from the first surface to the second surface. An operating beam is positioned spaced apart from the orifice plate. The operating beam comprises a base portion and a cantilever portion, the base portion being a predetermined distance from the orifice plate, and the cantilever portion extending from the base portion toward the orifice, with the overlapping portion overlapping the orifice. The operating beam is movable between a closed position and an open position. A sealing structure is positioned on the operating beam. The sealing structure comprises a sealing member positioned in the overlapping portion of the cantilever portion. A constriction portion is positioned at the end of the sealing member. The constriction portion defines the surface of the sealing member facing the orifice. A sealing flap extends outward from the constriction portion and is configured to seal the orifice and close the microvalve when the operating beam is in the closed position. [Brief explanation of the drawing]

[0010] This disclosure will be better understood from the following detailed description in conjunction with the attached figures.

[0011] [Figure 1] Figure 1 is a perspective view of an injection assembly positioned within a holder, according to an exemplary embodiment. [Figure 2] Figure 2 is an exploded view of the injection assembly shown in Figure 1. [Figure 3] Figure 3 is a schematic cross-sectional view of the injection assembly shown in Figure 1. [Figure 4A] Figure 4A is a plan view of the injection assembly shown in Figure 1. Figure 4B is a schematic diagram of an adhesive structure that can be used in the injection assembly of Figure 1, according to an exemplary embodiment. [Figure 4B] Figure 4A is a plan view of the injection assembly shown in Figure 1. Figure 4B is a schematic diagram of an adhesive structure that can be used in the injection assembly of Figure 1, according to an exemplary embodiment. [Figure 5A] Figure 5A is a cross-sectional view of an injection assembly with a microvalve according to an exemplary embodiment. [Figure 5B] Figure 5B is a cross-sectional view of an injection assembly with a microvalve according to another exemplary embodiment. [Figure 6] Figure 6 is a cross-sectional view providing a more detailed view of the injection assembly shown in Figure 5A. [Figure 7A] Figure 7A is a cross-sectional view of the operating beam of a microvalve according to an exemplary embodiment. Figure 7B is a front cross-sectional view of the operating beam of Figure 7A according to another exemplary embodiment. [Figure 7B] Figure 7A is a cross-sectional view of the operating beam of a microvalve according to an exemplary embodiment. Figure 7B is a front cross-sectional view of the operating beam of Figure 7A according to another exemplary embodiment. [Figure 8] Figures 8, 9, 10, 11, 12, and 13 are cross-sectional views of microvalve sealing structures according to various exemplary embodiments. [Figure 9]Figures 8, 9, 10, 11, 12, and 13 are cross-sectional views of the sealing structure of a microvalve according to various exemplary embodiments. [Figure 10] Figures 8, 9, 10, 11, 12, and 13 are cross-sectional views of the sealing structure of a microvalve according to various exemplary embodiments. [Figure 11] Figures 8, 9, 10, 11, 12, and 13 are cross-sectional views of the sealing structure of a microvalve according to various exemplary embodiments. [Figure 12] Figures 8, 9, 10, 11, 12, and 13 are cross-sectional views of the sealing structure of a microvalve according to various exemplary embodiments. [Figure 13] Figures 8, 9, 10, 11, 12, and 13 are cross-sectional views of the sealing structure of a microvalve according to various exemplary embodiments. [Figure 14] Figures 14 and 15 are cross-sectional views of the sealing structure of a microvalve according to various exemplary embodiments. [Figure 15] Figures 14 and 15 are cross-sectional views of the sealing structure of a microvalve according to various exemplary embodiments. [Figure 16] Figure 16 is a bottom view of a sealing member including three sets of concentric sealing blades according to an embodiment. [Figure 17] Figure 17 is a flowchart of a method of constructing a sealing structure of a microvalve according to an exemplary embodiment. [Figure 18] Figure 18 is a cross-sectional view of a sealing structure of a microvalve according to an exemplary embodiment. [Figure 19] Figure 19 is a flowchart of a method of constructing a sealing structure of a microvalve according to an exemplary embodiment. [Figure 20] Figure 20 is a flowchart of a method of constructing a microvalve according to an exemplary embodiment. [Figure 21] Figure 21 is a cross-sectional view of a sealing member of a microvalve according to an exemplary embodiment. [Figure 22] Figure 22 is a cross-sectional view of a valve sheet of a microvalve according to an exemplary embodiment. [Figure 23] Figure 23 is a cross-sectional view of a sealing structure of a micro-valve according to another exemplary embodiment. [Figure 24] Figure 24 is a schematic process flow for forming a sealing structure on a valve sheet according to another exemplary embodiment. [Figure 25] Figure 25 is a cross-sectional view of a micro-valve that may be provided in an injection assembly according to an exemplary embodiment. [Figure 26] Figure 26 is an enlarged view of a part of the injection assembly of Figure 25 indicated by arrow A in Figure 25. [Figure 27] Figure 27 is a top cross-sectional view of a sealing blade provided in the micro-valve of Figures 25 to 26 taken along line B-B in Figure 26. [Figure 28A] Figure 28A is a cross-sectional view of a part of an injection assembly according to an embodiment. Figure 28B is an enlarged view of a part of the injection assembly of Figure 28A indicated by arrow B in Figure 28A. [Figure 28B] Figure 28A is a cross-sectional view of a part of an injection assembly according to an embodiment. Figure 28B is an enlarged view of a part of the injection assembly of Figure 28A indicated by arrow B in Figure 28A. [Figure 29] Figure 29 is a side cross-sectional view of an injection assembly according to another embodiment. [Figure 30] Figure 30 is a cross-sectional view of an operating beam of an injection assembly according to an exemplary embodiment. [Figure 31] Figure 31 is a cross-sectional view of an operating beam of an injection assembly according to an exemplary embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] Before looking at the figures that illustrate the exemplary embodiments in detail, it should be understood that this application is not limited in detail or method to what is described in the mode for carrying out the invention or illustrated in the figures. It should also be understood that the terms are for the purpose of explanation only and are not to be regarded as limiting.

[0013] Generally with reference to the figures, an injection assembly comprising multiple microvalves is described herein. The microvalves described herein use an actuation beam having a sealing member positioned above it. By utilizing such an actuation beam, it becomes possible to adjust the microvalve to eliminate or reduce various defects associated with the prior art, including continuous inkjet assemblies. For example, in various embodiments, the microvalve comprises a spacer member positioned between the actuation beam and an orifice plate. The spacer member maintains the distance between the first end of the actuation beam and the orifice in the orifice plate, preventing squeeze film damping of the actuation beam. The actuation beam extends from the spacer member over the orifice, and the sealing member extends toward the orifice, forming a seal at the orifice. Thus, without applying electrical energy to the actuation beam, the sealing member seals the orifice. In other words, the initial position of the actuation beam (composed, for example, by carefully selecting the material contained therein) is that the microvalve is closed. Thus, the fluid contained within the microvalve (e.g., ink, solvent, etc.) is sealed from the external environment of the injection assembly. This eliminates liquid evaporation, reducing clogging. Furthermore, limiting evaporation allows for the use of faster-drying inks, resulting in faster printing than conventional systems.

[0014] To ensure superior performance of the injection assembly, the microvalve described herein includes a sealing structure configured to form a seal that separates the orifice from the volume adjacent to the working beam when the working beam is in its initial position. The sealing structure may comprise any combination of multiple components designed to ensure the formation of a seal. For example, in various embodiments, the sealing structure includes a valve seat positioned adjacent to the orifice on an orifice plate. The valve seat may surround the orifice and overlap with the orifice to define an opening that defines a fluid outlet. The sealing member may be in contact with the valve seat when the working beam is in its initial position. In some embodiments, the valve seat is made of a suitable material to facilitate the formation of an enhanced seal resulting from the pressure applied by the curvature of the working beam.

[0015] In another embodiment, the sealing structure may comprise components attached to or extending from the sealing member. For example, in one embodiment, the sealing structure comprises a stopper extending from the orifice-facing surface of the sealing member. The stopper may comprise a constricted portion and a wider portion having a cross-sectional area larger than that of the orifice. As a result, the working beam presses the stopper toward the orifice plate, facilitating the formation of a seal. Alternatively or additionally, the sealing structure may comprise a sealing blade extending from the orifice-facing surface to contact the valve seat or orifice plate. The sealing blade further facilitates the formation of a seal by the pressure resulting from its relatively small cross-sectional area, thereby concentrating the downward pressure applied by the working beam at a single point to form a seal. Thus, the various structures described herein enhance the seal formed when the working beam is in its initial position.

[0016] As described herein, when the term “initial position” is used to describe the working beam of a microvalve, it describes the position of the working beam relative to various other components of the microvalve without applying any control signals (e.g., charge, current, or voltage) to the working beam. In other words, when the working beam is in a passive state, the initial position is the position of the working beam (and any components attached to it). Naturally, another embodiment is conceivable in which the initial position is the open position of the working beam.

[0017] Referring here to Figure 1, a perspective view of an injection assembly 100, arranged within a holder 150, according to an exemplary embodiment, is shown. The injection assembly 100 comprises a valve body 102 mounted on a carrier 108. The holder 150 comprises a substantially circular body having a housed opening configured to receive the injection assembly 100. The body of the holder 150 may have notches 118 extending from its periphery to facilitate mounting the holder 150 to a marking device. The valve body 102 may also be a component of the marking device. In one exemplary embodiment, the valve body 102 is used in an industrial marking device comprising a pressurized ink supply unit. In another embodiment, the valve body 102 or any of the microvalves described herein may be used in pneumatic applications where the fluid is a gas (e.g., air, nitrogen, oxygen, etc.).

[0018] As described herein, the valve body 102 comprises an input fluid manifold attached to a plurality of microvalves. The microvalves and input fluid manifold form a fluid plenum or fluid reservoir configured to hold fluid received from an external fluid supply. In another embodiment, the valve body 102 may define a plurality of fluid plenums, each fluid plenum corresponding to at least a portion of the plurality of microvalves. In such an embodiment, each fluid plenum may be filled with inks of different colors (e.g., black, green, yellow, cyan, etc.) or different fluids to provide a multicolorable injection assembly or a multifluid deposition assembly. In various embodiments, the microvalves include an actuation beam configured to move (e.g., bend, curve, twist, etc.) in response to a voltage applied thereto, and to temporarily open a fluid outlet at the orifice of an orifice plate. As a result, droplets are ejected from the fluid outlet onto an object, generating a desired marking pattern on the object.

[0019] As shown, the circuit board 104 is mounted on the side of the carrier 108. The circuit board 104 may have multiple electrical paths and may provide connection points (e.g., via a wire harness) between the valve body 102 and the electrical controller. The electrical controller may supply control signals via the electrical paths to control the operation of the actuation beams of multiple microvalves provided in the valve body 102. The structure and function of such microvalves will be described in more detail herein. In some embodiments, the circuit board 104 itself includes a microcontroller that generates and provides control signals to actuate the microvalves.

[0020] The identification tag 106 is attached to the injection assembly 100. In some embodiments, the identification tag 106 includes an internal memory configured to store various forms of information about the injection assembly 100 (e.g., manufacturing information, serial number, valve calibration information, settings, etc.). For example, in one embodiment, the identification tag 106 is a radio frequency identification (RFID) tag configured to transmit the stored information in a receivable manner in response to receiving a predetermined identifier from an external device. In this way, information about the injection assembly 100 may be obtained quickly and efficiently.

[0021] Referring here to Figure 2, an exploded view of the injection assembly 100 according to an exemplary embodiment is shown. The carrier 108 comprises a front 110, a rear 112, and a side 124. In various embodiments, the valve body 102 is attached to the front 110 with adhesive. The rear 112 has a cover 116 positioned on top of it. The cover 116 has an opening 120 that provides a supply port for a fluid (e.g., ink) to be deposited onto an object via the valve body 102. For example, in some embodiments, the fluid (e.g., ink) is supplied to the valve body 102 through a first opening of the opening 120 (e.g., via an input supply line or hose), circulates through the valve body 102, and is discharged from the valve body 102 through a second opening of the opening 120. In other words, the fluid is recirculated through the fluid plenum. Partitions may be positioned at each of the openings 120 and configured to allow fluid delivery or insertion of a fluid return needle through them, enabling fluid communication into the fluid plenum while maintaining fluid sealing of the injection assembly 100. In certain embodiments, the partitions may comprise a single partition sheet extending below each of the first and second openings of the opening. Although not shown, in some embodiments, a heating element (e.g., a resistive element) may be positioned close to the valve body 102 or carrier 108 (e.g., around or connected to its sidewall). The heating element may be used to selectively heat the fluid (e.g., ink) contained in the fluid plenum in order to maintain the fluid at a desired temperature. Furthermore, for example, a temperature sensor (not shown), such as a thermal sensing resistor, may be provided in the carrier 108 to measure the temperature of the fluid flowing through the injection assembly 100.

[0022] The front surface 110 includes a cavity configured to receive the valve body 102 so that the valve body 102 is firmly attached to the front surface 110 (for example, by adhesive). The circuit board 104 is attached to the carrier 108 via the side surface 124. As shown, the side surface 124 includes mounting pegs 126. In various embodiments, the circuit board 104 includes openings positioned to accommodate the arrangement of the mounting pegs 126 and is configured to receive the mounting pegs 126 for aligning the circuit board 104 with the carrier 108.

[0023] As shown, the circuit board 104 has a flex circuit 114 attached thereto. The flex circuit 114 extends from the circuit board 104 at an angle and is attached to the carrier 108 in close proximity to the front surface 110. The valve body 102 and the circuit board 104 are positioned perpendicular to each other when the flex circuit 114 extends near the corner boundary of the front surface 110. The circuit board 104 also includes a controller interface 122 having electrical connection members (e.g., pins) configured to receive control signals from the marking system controller.

[0024] As described herein, in various embodiments, the flex circuit 114 may be positioned between the fluid manifold and the carrier 108, or an interposer may be positioned between the carrier 108 and the valve body 102 to facilitate the formation of electrical connections between the flex circuit 114 and the electrodes of a plurality of microvalves provided in the valve body 102. In some embodiments, the flex circuit 114 is mounted to the front surface 110 by a mounting member 148. The opening of the flex circuit 114 is aligned with the bulkhead of the carrier 108 and provides a fluid inlet to a fluid plenum formed via the valve body 102.

[0025] Referring here to Figure 3, a schematic diagram of the various components of the injection assembly 100 according to an exemplary embodiment is shown. For example, Figure 3 can show a cross-sectional view of the injection assembly 100 shown in Figure 1 along line II. As shown, the valve body 102 extends from the front surface 110 of the carrier 108 via the interposer 170. The interposer 170 provides a structural support that ensures maximum performance of the various components within the valve body 102. Although not shown, in some embodiments a fitting layer (e.g., a silicone or rubber layer) may also be placed above or below the interposer 170, or at any other arbitrary position in the stack, to relieve stress.

[0026] The valve body 102 comprises an input fluid manifold 162 and a plurality of microvalves 164 attached to the input fluid manifold 162. The microvalves 164 and the input fluid manifold 162 form a fluid plenum or fluid reservoir 166 for fluid (e.g., a combination of ink and makeup fluid) received from a pressurized fluid supply unit (e.g., through an opening 120 in a cover 116 attached to the rear 112). In various embodiments, the fluid supply unit comprises a fluid reservoir and a pump configured to supply pressurized fluid to the injection assembly 100 via a supply line connected to a carrier 108. In various embodiments, the fluid supply unit supplies fluid pressurized to 7 to 15 PSI when one or more of the microvalves 164 are open. For example, in one embodiment, the fluid has a pressure of about 10 PSI. The carrier 108 may have an internal cavity configured to receive pressurized fluid and supply the fluid to the fluid plenum 166. In various embodiments, a pressure difference may be maintained between the fluid plenum and the fluid supply unit to expel the fluid from the valve body 102.

[0027] The input fluid manifold 162 may comprise a glass structure having a channel that forms a fluid plenum. Generally, the microvalve 164 comprises an actuation beam held spaced apart from an orifice on an orifice plate on the front surface 110. The actuation beam may comprise at least one layer of piezoelectric material configured to flex in response to the reception of a control signal (e.g., a voltage waveform provided via a controller interface 122 on a circuit board 104). As described herein, the application of such an electrical signal causes the microvalve 164 to open, thereby releasing a droplet at the orifice plate. The droplet is ejected onto the substrate 190 from an ejection distance 192 to create a desired pattern on the substrate 190. In some embodiments, the weight of a single fluid droplet dispensed by the microvalve 164 or any other microvalve described herein may range from 200 nanograms to 300 nanograms. In some embodiments, the volume of a single droplet dispensed may range from 200 picoliters to 300 picoliters. The structure and function of various components of the microvalve 164 are described in more detail herein. In another embodiment, the working beam may comprise a stainless steel working beam (for example, having a length of about 1 mm). In yet another embodiment, the working beam may comprise a bimorph beam having two layers of piezoelectric material disposed on either surface of a base layer (for example, a base silicon or stainless steel layer). An electrical signal (for example, a voltage) may be applied to one of the piezoelectric layers to bend the working beam toward the corresponding piezoelectric layer. The two piezoelectric layers may comprise the same piezoelectric material or different piezoelectric materials. In a particular embodiment, different electrical signals may be applied to each of the piezoelectric layers to bend or curve the working beam toward or away from the orifice.

[0028] The embodiments described herein generally describe working beams comprising piezoelectric materials, but in other embodiments, any other acting mechanism may be used. For example, in some embodiments, the working beam may include a capacitive coupling for moving the working beam. In another embodiment, the working beam may include an electrostatic coupling. In yet another embodiment, the working beam may include a magnetic coupling (e.g., an electromagnetic structure actuated by an electromagnet) for moving the beam. In yet another embodiment, the working beam may include a temperature-sensitive bimetallic plate configured to move in response to temperature changes.

[0029] The interposer 170 generally adds rigidity to various parts of the valve body 102. For example, the interposer 170 may be configured to be more rigid than the components of the valve body 102 (e.g., orifice plate, working beam, etc.), and the stresses induced by mounting these components to each other may be offset. For example, the interposer 170 may be attached to the valve body 102 to offset the stresses induced by the adhesive used to attach the carrier 108 to the valve body 102. Furthermore, the interposer 170 may offset stresses at the interface between the input fluid manifold 162 and the microvalve 164.

[0030] Referring now to Figure 4A, a plan view of the injection assembly 100 according to an exemplary embodiment is shown. Figure 4A shows a plan view of the valve body 102 shown in Figure 2 along line II-II. In other words, Figure 4A shows a cross-sectional view of the interface between the input fluid manifold 162 and the orifice plate. The input fluid manifold 162 comprises a first opening 172 and a second opening 174. The first opening 172 forms a fluid plenum 166 configured to hold fluid that is received from the fluid supply section, exposing a plurality of microvalves 164.

[0031] In the embodiments shown, a plurality of microvalves 164 comprises a plurality of aligned actuation beams 176. Each of the plurality of actuation beams 176 has a sealing member 178 positioned at its end. In some embodiments, the sealing member 178 is aligned with and in contact with a valve seat positioned in an orifice within an orifice plate, preventing the fluid contained in the fluid plenum 166 from leaking out of the fluid plenum 166 in the absence of any electrical signal. The injection assembly 100 is shown to comprise 52 actuation beams 176 forming 52 microvalves 164.

[0032] In various embodiments, each of the multiple workbench beams 176 may have an electrical connection exposed through a second opening 174. An electrical contact pad 180 is placed at each of the electrical connections. A wire bond electrically connects each of the electrical connections to the controller interface 122 via the electrical contact pad 180. That is, electrical signals may be received by each of the workbench beams 176 via the electrical contact pad 180. In some embodiments, tape automatic bonding (TAB) may be used to electrically connect each of the electrical connections to the controller interface.

[0033] The boundary between the first opening 172 and the second opening 174 separates the electrical contact pad 180 from the fluid contained within the reservoir formed by the first opening 172. Furthermore, the electrical contact pad 180 is located beneath the input fluid manifold 162. This means that the electrical connections between the working beams 176 are located inside the carrier 108 and are protected from degradation and external contamination.

[0034] To separate the electrical contact pad 180 from the fluid contained in the fluid plenum 166, the adhesive structure 182 is positioned on the input fluid manifold 162. The adhesive structure 182 connects the input fluid manifold 162 to the orifice plate. As shown in Figure 4A, the adhesive structure 182 forms a “racetrack” around each of the first opening 172 and the second opening 174. The racetrack provides a barrier for fluid leakage between the input fluid manifold 162 and the orifice plate and prevents particles from entering the input fluid manifold. The racetrack-type adhesive structure 182 may be present on either the input fluid manifold 162 side or the orifice plate side, or both. For example, the racetrack may consist of several concentric rectangular loops of adhesive material (e.g., negative photoresist, e.g., bisphenol A novarac glycidyl ether-based photoresist commercially available under trade name SU-8, or polymethyl methacrylate, polydimethylsiloxane, silicone rubber, etc.) around each of the first opening 172 and the second opening 174. Segments of the adhesive material may cut across multiple segments of the rectangular loop to form compartments that receive leaking fluid. Such an adhesive structure 182 facilitates fluid separation between the microvalve 164 and the electrical contact pad 180. In another embodiment, the adhesive structure 182 is formed from silicon and is used to bond the input fluid manifold 162 to the orifice plate by fusion bonding, laser bonding, adhesive, eutectic bonding, glass frit, solder, stiction, etc. The adhesive structure 182 may be placed on the input fluid manifold 162 and the valve body 102 connected thereto, or on the valve body 102 and the input fluid manifold 162 connected thereto, or on the input fluid manifold 162 and the valve body 102 respectively before connecting the two.

[0035] In some embodiments, the adhesive structure 182 may be ventilated. For example, Figure 4B shows a schematic diagram of the adhesive structure 182b. The adhesive structure 182b may be formed from SU-8, silicon, or any other suitable material, and comprises a plurality of loops 189b such that the adhesive structure has a racetrack shape. The innermost loop of the plurality of loops 189b of the adhesive structure 182b surrounding the input fluid manifold 162 forms a closed loop. In contrast, the remaining portion of the plurality of loops 189b located radially outward from the innermost loop comprises vents 183b, for example, grooves or openings defined therein. The vents 183b may facilitate bonding to the orifice plate of the input fluid manifold 162 by allowing air that may be trapped between the plurality of loops 189b of the adhesive structure 182b to leak out through the vents 183b. Figure 4B shows that the vents 183b are radially aligned with each other and located at the corners of each loop. In another embodiment, one or more vents 183b in a loop may be radially offset from vents defined in adjacent loops.

[0036] As shown in Figure 4B, the corners of each loop in the adhesive structure 182b may be rounded. Furthermore, the corners of the input fluid manifold 162, the interposer 170, the flex circuit 114, or any other layer or component provided in the injection assembly 100 may be rounded, for example, to reduce stress concentration that may occur at sharp corners.

[0037] Referring here to Figure 5A, a cross-sectional view of an injection assembly 200 comprising a microvalve 230 is shown according to an exemplary embodiment. In some embodiments, the injection assembly 200 is an exemplary embodiment of the injection assembly 100 described with respect to Figures 1, 2, 3, and 4A-4B. As shown, the injection assembly 200 comprises a carrier 202 attached to the valve body 298 via a structural layer 222. In some embodiments, the carrier 202 may comprise the structural layer 222.

[0038] The carrier 202 comprises an upper section 204 and a housing section 206 extending from the edge of the upper section 204. The upper section 204 includes a partition wall 208 into which pressurized ink is supplied. The housing section 206 defines a cavity in which a valve body 298 is placed. The valve body 298 comprises an input fluid manifold 210 and a microvalve 230. As shown, the input fluid manifold 210 and the microvalve 230 define a reservoir 300 configured to hold a volume of pressurized fluid received from an external fluid supply via the partition wall 208. In various embodiments, the pressurized fluid held in the reservoir 300 is a combination of ink and another fluid in a liquid state.

[0039] The carrier 202 may be formed of plastic, ceramic, or any other suitable material. The carrier 202 facilitates the operation of the injection assembly 200 by providing a structural support on the valve body 298. For example, in some embodiments, the periphery of the valve body 298 is attached to the housing 206 by a layer of adhesive 302 placed on the inner surface of the housing 206. Such adhesive facilitates the maintenance of the desired relative positioning between the microvalve 230 and the input fluid manifold 210.

[0040] In various embodiments, the input fluid manifold 210 is pre-formed before attachment to another component of the injection assembly 200. The input fluid manifold 210 is formed by a body 310 having any preferred thickness (e.g., 500 microns) (formed from, for example, glass, silicon, silica, etc.). As shown, the input fluid manifold 210 is pre-formed to include a first arm 330, a second arm 332, and a third arm 334. The term “arm” as used herein, when used to describe the input fluid manifold 210, is used to describe a structure that separates the openings contained within the input fluid manifold 210. Thus, the arms 330, 332, and 334 may have any preferred shape. For example, in some embodiments, the arms 330, 332, and 334 are substantially rectangular in shape with substantially planar sides. In other embodiments, the sides may be angled so that the arms 330, 332, and 334 are substantially trapezoidal in shape. Arms 330, 332, and 334 may be formed by creating openings within a structure (e.g., a silicon or glass structure) using any preferred method (e.g., wet etching or dry etching, e.g., deep reactive ion etching).

[0041] As shown, the first channel 212 separates arms 330 and 332 from each other, and the second channel 214 separates arms 332 and 334 from each other. In the embodiment shown, the first channel and the second channel 214 are substantially linear and parallel to each other, but the input fluid manifold 210 may be positioned as necessary for the arrangement of microvalves placed thereon. The first channel 212 is formed to have a width 304, for example, in the range of about 500 to 1,000 microns, which has a predetermined relationship with the length 312 of the cantilevered portion 308 of the working beam 240 of the microvalve 230. For example, the first channel 212 may be formed to have a width 304 that is greater by a threshold amount than the desired length 312 of the cantilevered portion 308. The second channel 214 provides means for an electrical connection formed between the working beam 240 and the flex circuit 216 via a wire bond 220 extending between them. Advantageously, this arrangement incorporates the electrical connection between the working beam 240 and the flex circuit 216 internally. In other words, the electrical connection between such components is not external to the carrier 202 and is therefore less vulnerable to degradation. In various embodiments, the first channel 212 and / or the second channel 214 may have inclined sidewalls.

[0042] As shown, the second channel 214 is substantially filled with a encapsulant 218. The encapsulant 218 may include an epoxy type or any other suitable material. The encapsulant 218 is configured to cover the wire bond 220 and the electrical connection formed between the flex circuit 216 and the actuation beam 240, protecting the wire bond 220 from physical damage, moisture, and corrosion. Thus, the encapsulant 218 ensures the maintenance of a proper electrical connection between the flex circuit 216 and the actuation beam 240, facilitating the provision of electrical control signals to the actuation beam 240 to move it, opening and closing the microvalve 230.

[0043] The second arm 332 functions as a barrier to prevent the fluid contained in the reservoir 300 from reaching the electrical connections. The portion 314 of the input fluid manifold 210 separating the first channel 212 and the second channel 214 also functions as a barrier to prevent the fluid contained in the reservoir 300 from reaching the electrical connections. In other words, the input fluid manifold 210 functions as both a reservoir 300 for pressurized fluid received from an external fluid supply and an insulating barrier between the pressurized fluid and any electrical connections contained within the injection assembly 200. The first channel 212 and the second channel 214 may be formed using any preferred process (e.g., by sandblasting, physical or chemical etching, drilling). In some embodiments, the input fluid manifold 210 is constructed of silicon, silica, ceramic, or any other preferred material rather than glass. In some embodiments, the input fluid manifold 210 may be bonded to the microvalve 230 by glass frit, solder, or any other preferred adhesive.

[0044] Continuing to refer to Figure 5A, the microvalve 230 comprises an orifice plate 250 attached to the working beam 240. The orifice plate 250 may be formed from any suitable material, e.g., glass, stainless steel, nickel, nickel with another layer of electroplated metal (e.g., stainless steel), polyimide (e.g., Kapton), or negative photoresist (e.g., SU-8, polymethyl methacrylate, etc.). In some embodiments, the orifice plate 250 may be substantially flat, for example, having a flatness with a coefficient of variation of less than 3 microns over at least 15 mm of the length and width of the orifice plate 250, such that the orifice plate 250 is substantially free from warping or bending. Furthermore, the orifice plate 250 may have any suitable thickness. In some embodiments, the orifice plate 250 may have a thickness in the range of 30 to 60 microns (30, 40, 50, or 60 microns). In another embodiment, the orifice plate 250 may have a thickness in the range of 100 to 400 microns (e.g., 100, 150, 200, 250, 300, 350, or 400 microns). A thicker orifice plate 250 may facilitate the creation of a flatter orifice plate.

[0045] The orifice plate 250 is substantially planar and comprises an orifice 260 extending between its surfaces. In various embodiments, the orifice 260 is substantially cylindrical and has a central axis perpendicular or substantially perpendicular to the surface of the orifice plate 250. The valve seat 270 is positioned on the inner surface 316 of the orifice plate 250 in close proximity to the orifice 260. In various embodiments, the valve seat 270 consists of a conforming material that surrounds or substantially surrounds the orifice 260. In some embodiments, the valve seat 270 is composed of an epoxy adhesive, such as SU-8 photoresist. In another embodiment, the valve seat 270 may be formed from a moldable polymer, such as polydimethylsiloxane or silicone rubber. In yet another embodiment, the valve seat 270 may be formed from a non-conforming material, such as silicon. In some embodiments, a conforming layer, such as a gold layer, may be placed on the surface of the valve seat 270 in contact with the working beam 240. The valve seat 270 defines an internal opening 318 substantially aligned with the orifice 260, forming an outlet for the pressurized fluid contained within the reservoir 300. In certain embodiments, the valve seat 270 may be omitted.

[0046] As shown, the working beam 240 comprises a base portion 306 and a cantilever portion 308. The base portion 306 extends beneath a portion 314 of the input fluid manifold 210 that separates the first channel 212 from the second channel 214. As shown, the base portion 306 includes an electrical connection portion 294 in the region overlapping with the second channel 214. The electrical connection portion 294 includes electrodes through which an electrical connection is formed with the flex circuit 216 via a wire bond 220. The cantilever portion 308 extends from portion 314 of the input fluid manifold 210 into the reservoir portion 300. As shown, the cantilever portion 308 is positioned on a spacer member 280 and is consequently spatially separated from the orifice plate 250. Therefore, as a result of an electrical signal being applied to the actuation beam 240 via the electrical connection 294, there is space on both sides of the cantilever beam 308 so that the actuation beam 240 can bend toward and / or away from the orifice plate 250. The spacer member 280 is configured to prevent squeeze film damping of the actuation beam.

[0047] The cantilever beam 308 has a length 312 such that the cantilever beam extends a predetermined distance from the boundary of the reservoir 300. In various embodiments, the predetermined distance is selected such that a portion 292 of the cantilever beam 308 overlaps with the valve seat 270 and the orifice 260. The sealing member 290 extends from a portion 292 of the working beam 240 that overlaps with the orifice 260. In some embodiments, the sealing member 290 is configured to have a shape substantially corresponding to the shape of the orifice 260. For example, in one embodiment, both the orifice 260 and the sealing member 290 are substantially cylindrical, with the sealing member 290 having a larger outer diameter. Such a configuration makes it easier for the sealing member 290 to cover the entire orifice 260 in order to form a seal between the sealing member 290 and the valve seat 270. In another embodiment, the orifice 260 may have any other shape, such as star-shaped, square, rectangular, polygonal, elliptical, or asymmetrical. In a particular embodiment, the valve seat 270 may define the size and shape of a recess to receive the sealing member 290. In various embodiments, the orifice plate 250 and therefore the orifice 260 may be formed from a non-wetting (e.g., hydrophobic) material, such as silicon or Teflon®. In another embodiment, a non-wetting (e.g., hydrophobic) coating may be placed on the inner wall or surface of the orifice 260, or at the fluid outlet formed by the valve seat 270 and the orifice 260. Examples of such coatings include Teflon®, nanoparticles, lipophilic coatings, or any other suitable coating.

[0048] In various embodiments, the spacer member 280 and the sealing member 290 are made of the same material and have equivalent or substantially equivalent thicknesses 320 and 322 (e.g., silicon, SU-8, silicon rubber, polymethyl methacrylate, etc.). In such embodiments, when the working beam 240 extends parallel to the orifice plate 250, the lower surfaces of the spacer member 280 and the sealing member 290 are aligned with each other. When the working beam 240 is positioned in the closed position (as described herein), the surface of the sealing member 290 contacts the valve seat 270 to close the fluid outlet formed in the orifice 260 (for example, the sealing member surface of the sealing member 290 may be configured to extend about 2 microns below the lower surface of the spacer member 280 when the valve seat 270 is not present). The valve seat 270 and the sealing member 290 are sized such that, when the working beam 240 is in the closed position (for example, when an electrical signal is removed from or applied to the working beam 240 via the wire bond 220), a sufficient surface area of ​​the sealing member 290 contacts the valve seat 270, preventing fluid from moving from the reservoir 300 to the orifice 260. For example, the sealing member 290 may have a larger diameter or cross-section than the valve seat 270. In another embodiment, the sealing member 290 may have a smaller diameter or cross-section than the valve seat 270. In some embodiments, a suitable material (e.g., a gold layer) may be placed on the surface of the sealing member 290 configured to contact the valve seat 270.

[0049] Various embodiments of the injection assembly 200 are designed to ensure proper sealing between the valve seat 270 and the sealing member 290. For example, a structural layer 222 positioned on the input fluid manifold 210 connects the components of the microvalve 230 to each other and prevents warping of the orifice plate 250 resulting from stress induced thereon by the adhesive connecting the microvalve 230 to the housing portion 206. In various embodiments, the structural layer 222 is configured to have greater rigidity than the orifice plate 250 in order to perform this function. The structural layer 222 may be made of silicon or any other suitable material. As shown, the structural layer 222 includes projections 224 extending from its main portion. The projections 224 are mounted on the upper surface of the input fluid manifold 210 (for example, at the boundary between the first channel 212 and the second channel 214). In certain embodiments, the projections 224 are omitted. The sealing is formed by projections 224, for example, by an adhesive placed between the structural layer 222 and the flexible circuit 216. The projections 224 provide clearance above the input fluid manifold 210. Such clearance facilitates the placement of a sealant 218 that completely covers all contact points between the wire bond 220 and the flexible circuit 216. In some embodiments, the carrier 202 may comprise the structural layer 222 so that rigidity is provided by the carrier 202.

[0050] In another embodiment, the actuating beam 240 is configured such that, when in the closed position, a seal is formed at the interface between the valve seat 270 and the sealing member 290. The actuating beam 240 may comprise at least one layer of piezoelectric material. The layer of piezoelectric material may include lead zirconate titanate (PZT) or any suitable material. The layer of piezoelectric material has electrodes electrically connected thereto. In various embodiments, a wire bond 220 is attached to the aforementioned electrodes so that an electrical signal from the flex circuit 216 is supplied to the layer of piezoelectric material via the electrodes. The electrical signal causes the actuating beam 240 to move relative to its initial position (e.g., bend, rotate, etc.). In yet another embodiment, the actuating beam 240 may comprise a stainless steel actuating beam (e.g., having a length of about 1 mm). In yet another embodiment, the actuating beam 240 may comprise a bimorph beam having two layers of piezoelectric material disposed on either surface of a base layer (e.g., a base silicon layer). An electrical signal (e.g., voltage) may be applied to one of the piezoelectric layers to bend the actuating beam toward the corresponding piezoelectric layer. The two piezoelectric layers may comprise the same piezoelectric material or different piezoelectric materials. In certain embodiments, different electrical signals may be applied to each of the piezoelectric layers to bend or curve the working beam to a predetermined distance.

[0051] As shown, the wire bond 220 is attached to the working beam 240 at its electrical connection 294. The electrical connection 294 comprises a wire bonding pad (e.g., made of gold, platinum, rubidium, etc.) which is electrically connected to at least one electrode in the working beam 240. Advantageously, the electrical connection 294 is separated from the cantilevered portion of the working beam 240. In other words, the electrical connection 294 is separated from the fluid contained in the injection assembly 200 by a seal formed at the connection point between the input fluid manifold 210 and the working beam 240. In some embodiments, the wire bond 220 and / or the sealant 218 may exit the path through an opening provided in the orifice plate 250.

[0052] In various embodiments, the actuating beam 240 is configured such that its initial position is the closed position. In other words, the various layers within the actuating beam 240 are configured such that the actuating beam bends toward the orifice 260 as a result of the force applied by the pressurized fluid contained in the reservoir. The tuning layer within the actuating beam 240 may be configured to be under compressive stress to cause the actuating beam to bend toward the orifice. As a result of such bending, the sealing member 290 contacts the valve seat 270, for example, without any electrical signal being applied to the actuating beam 240 to close the fluid outlet. The degree of bending may be particularly selected so as to form a seal at the interface between the sealing member 290 and the valve seat 270 when the actuating beam 240 is in its initial position. Advantageously, such an initial seal prevents evaporation of the fluid contained in the injection assembly 200, which prevents clogging and other defects.

[0053] As shown in Figure 5A, the working beam 240 is bent away from the orifice plate 250. This bending is achieved by applying an electrical signal to the working beam 240 via the flex circuit 216. For example, the flex circuit 216 may be electrically connected to an external controller that supplies the electrical signal transmitted to the working beam 240.

[0054] As illustrated in Figure 5A, the application of an electrical signal temporarily moves the actuating beam 240 away from its initial position. For example, in various embodiments, the actuating beam 240 moves upward away from the orifice 260 such that a portion of the sealing member surface of the sealing member 290 is at least 10 microns from the upper surface of the valve seat 270. In one embodiment, the center of the sealing member surface is about 15 microns from the valve seat 270 at the peak of its vibration pattern. As a result, an opening is temporarily formed between the valve seat 270 and the sealing member 290. The opening provides a path for the fluid volume to enter the orifice 260 and form droplets on the outer surface of the orifice plate 250. The droplets accumulate on the substrate and form a pattern determined by the control signals sent to each of the actuating beams 240 of the microvalve 230 of the injection assembly 200. As understood, the frequency, which moves the actuating beam 240 from its initial position to a certain position, for example, the position shown in Figure 5, may vary depending on the implementation. For example, in one embodiment, the working beam 240 oscillates at a frequency of approximately 12 kHz. However, in another implementation, the working beam 240 may oscillate at a lower frequency (e.g., 10 kHz) or a higher frequency (e.g., 20 kHz).

[0055] Referring here to Figure 5B, a cross-sectional view of an injection assembly 200b comprising a microvalve 230b is shown according to an exemplary embodiment. In some embodiments, the injection assembly 200b is an exemplary embodiment of the injection assembly 100 described with respect to Figures 1, 2, 3, and 4A-4B. As shown, the injection assembly 200b comprises a carrier 202b attached to the valve body 298b via an interposer 222b.

[0056] The carrier 202b comprises an upper section 204b and a housing section 206b extending from the edge of the upper section 204b. A fluid channel 211b is provided in the upper section 204b. A partition wall 208b (e.g., a rubber or foam partition wall) is located at the inlet of the fluid channel 211b, and a filter 213b is located at the outlet of the fluid channel 211b. A cover 203b (e.g., a plastic or glass cover) is positioned on the carrier 202b such that the partition wall 208b is positioned between the carrier 202b and the cover 203b and secured between them. An opening 209b may be defined within the cover 203b and corresponds to the inlet of the fluid channel 211b. A fluid connector 10b connects to the cover 203b or the inlet of the fluid channel 211b. The fluid connector 10b comprises an insertion needle 12b, which is configured to penetrate a partition wall 208b and pass through it into the fluid channel 211b. The fluid connector 10b is configured to inject a pressurized fluid (e.g., ink) through the insertion needle 12b into the input fluid manifold 210b of the injection assembly 200b. Furthermore, the filter 213b is configured to filter particles from the fluid before the fluid communicates with the reservoir 300b. In some embodiments, the insertion needle 12b may be formed from a non-wetting material (e.g., a hydrophobic material, e.g., Teflon®) or coated with a non-wetting material. In another embodiment, the insertion needle 12b may be equipped with a heating element, or an electric current may be supplied to the insertion needle 12b to heat the insertion needle 12b, thereby causing the fluid to flow through it into the reservoir 300b. In yet another embodiment, a metal needle or any other heating element may be provided in the input fluid manifold 210b to heat the fluid contained therein. Although it is shown that only the fluid channel 211b is provided, in some embodiments the carrier 202b may also define a second fluid channel so that the fluid is drawn out of the carrier 202b, i.e., the fluid circulates through the carrier 202b.

[0057] The housing portion 206b defines a cavity or boundary in which the valve body 298b is placed. The valve body 298 comprises an input fluid manifold 210b and a microvalve 230b. As shown, the input fluid manifold 210b and the microvalve 230b define a reservoir 300b configured to hold a volume of pressurized fluid received from an external fluid supply via a partition wall 208b. In various embodiments, the pressurized fluid held in the reservoir 300b is a combination of ink and another fluid in a liquid state.

[0058] In various embodiments, the input fluid manifold 210b is pre-formed before attachment to another component of the injection assembly 200b. The fluid manifold 210b may be formed by a glass body 310b having any preferred thickness (e.g., 500 microns). As shown, the input fluid manifold 210b is pre-formed to include a first channel 212b and a second channel 214b. The first channel 212b is formed to have a width 304b that has a predetermined relationship with the length 312b of the cantilevered portion 308b of the working beam 240b of the microvalve 230b. The second channel 214b provides a path for an electrical connection formed between the working beam 240b and the flex circuit 216b via a wire bond 220b extending between them.

[0059] As shown, the second channel 214b is substantially filled with the encapsulant 218b. The encapsulant 218b ensures the maintenance of a proper electrical connection between the flex circuit 216b and the work beam 240b, facilitating the transmission of electrical control signals to the work beam 240b to move it, opening and closing the microvalve 230b, and protecting the wire bond 220b from physical damage or moisture, as previously described herein.

[0060] The portion 314b of the input fluid manifold 210b separating the first channel 212b and the second channel 214b acts as a barrier to prevent the fluid contained in the reservoir 300b from reaching the electrical connections. In other words, the input fluid manifold 210b functions as both a reservoir 300b for pressurized fluid received from an external fluid supply and an insulating barrier between the pressurized fluid and any electrical connections contained within the injection assembly 200b.

[0061] The microvalve 230b comprises an orifice plate 250b mounted on the working beam 240b. The orifice plate 250b is substantially planar and comprises an orifice 260b extending between its surfaces. The valve seat 270b is positioned on the inner surface 316b of the orifice plate 250b in close proximity to the orifice 260b. The valve seat 270b defines an internal opening 318b substantially aligned with the orifice 260b and forms an outlet for the pressurized fluid contained within the reservoir 300b. In certain embodiments, the valve seat 270b may be omitted. In some embodiments, the orifice plate 250b or any other orifice plate described herein may also be grounded. For example, an electrical grounding connector 295b (e.g., a bonding pad, e.g., a gold bond pad) may be provided on the orifice plate 250b and configured so that the orifice plate 250b can be electrically grounded (e.g., via an electrical coupling to system ground).

[0062] The working beam 240b comprises a base portion 306b and a cantilever portion 308b. The base portion 306b extends beneath portion 314b of the input fluid manifold 210b, which separates the first channel 212b from the second channel 214b. As shown, the base portion 306b includes an electrical connection portion 294b in the region overlapping with the second channel 214b. The electrical connection portion 294b includes electrodes through which an electrical connection is formed with the flex circuit 216b via a wire bond 220b. The cantilever portion 308b extends from portion 314b of the input fluid manifold 210b into the reservoir portion 300b. As shown, the cantilever portion 308b is positioned on a spacer member 280b, and as a result is spatially separated from the orifice plate 250b.

[0063] The cantilevered beam 308b has a length 312b such that the cantilevered beam extends a predetermined distance from the boundary of the reservoir 300b. In various embodiments, the predetermined distance is selected such that a portion 292b of the cantilevered beam 308b overlaps with the valve seat 270b and the orifice 260b. The sealing member 290b extends from a portion 292b of the working beam 240b that overlaps with the orifice 260b. In some embodiments, the sealing member 290b is configured to have a shape substantially corresponding to the shape of the orifice 260b.

[0064] The flex circuit 216b is positioned on the glass body 310b and portion 314b of the input fluid manifold 210b, and is connected to it via a first adhesive layer 221b (e.g., SU-8, silicone rubber, adhesive, epoxy, etc.). The interposer 222b is positioned between the upper part 204b of the carrier 202b and the input fluid manifold 210b, so as to form a gap between the upper part 204b and the input fluid manifold 210b via the first adhesive layer 221b. This provides sufficient space for the encapsulant 218 and increases the volume of the input fluid manifold 210b. As shown in Figure 5B, the interposer 222b is positioned on and connected to portion of the flex circuit 216b via a second adhesive layer 223b (e.g., SU-8, silicone, or any other adhesive). Furthermore, the interposer 222b is connected to the microvalve 230b via a third adhesive layer 225b (e.g., SU-8, silicone, or any other adhesive) on the side wall of the upper part 204b of the carrier 202b, in close proximity to it.

[0065] The interposer 222b is formed from a strong, rigid material (e.g., plastic, silicon, glass, ceramic, etc.) and may be positioned on the input fluid manifold 210b, connecting the components of the microvalve 230b to each other and preventing warping of the orifice plate 250b caused by stress induced thereon via the adhesive connecting the microvalve 230b to the housing portion 206b. In various embodiments, the interposer 222b is configured to have greater rigidity than the orifice plate 250b in order to perform this function.

[0066] In another embodiment, the actuating beam 240b is configured such that, when in the closed position, a seal is formed at the interface between the valve seat 270b and the sealing member 290b. The actuating beam 240b may comprise at least one layer of piezoelectric material (e.g., lead zirconate titanate (PZT) or any suitable material). The layer of piezoelectric material has electrodes electrically connected thereto, and the wire bond 220b is attached to the aforementioned electrodes such that electrical signals from the flex circuit 216b are supplied to the layer of piezoelectric material via the electrodes. The electrical signals cause the actuating beam 240b to move relative to its initial position (e.g., bend, rotate, etc.).

[0067] As shown, the wire bond 220b is attached to the actuation beam 240b at its electrical connection 294b and is substantially the same as the wire bond 220 described with respect to the injection assembly 200 in Figure 5A. In various embodiments, the actuation beam 240b is configured such that its initial position is the closed position, as described in detail with respect to the actuation beam 240 in Figure 5A.

[0068] As shown in Figure 5B, the actuation beam 240b is bent away from the orifice plate 250b. This bending is achieved by applying an electrical signal to the actuation beam 240b via a flex circuit 216b. For example, the flex circuit 216b may be electrically connected to a circuit board 215b (e.g., a printed circuit board) extending perpendicularly to the longitudinal axis of the actuation beam 240b along the sidewall of the carrier 202b. An identification tag 217b (e.g., an identification tag 106) may be positioned between the circuit board 215b and the sidewall of the carrier 202b. An electrical connector 219b is configured to electrically connect the flex circuit 216b to an external controller that electrically couples to the circuit board 215b and supplies an electrical signal transmitted to the actuation beam 240b via the circuit board 215b.

[0069] As illustrated in Figure 5B, the application of an electrical signal temporarily moves the working beam 240b away from its initial position. As described in detail with respect to the working beam 240 in Figure 5A, for example, in various embodiments, the working beam 240b moves upward away from the orifice 260b such that a portion of the sealing surface of the sealing member 290b is at least 10 microns from the upper surface of the valve seat 270b.

[0070] Referring here to Figure 6, a more detailed diagram is shown showing various components of the injection assembly 200 described with respect to Figure 5A, according to an exemplary embodiment. As shown, the working beam 240 comprises an actuation section 242, a tuning layer 244, and an inert layer 246. The inert layer 246 serves as the base for the tuning layer 244 and the actuation section 242. The structure of the actuation section 242 and the tuning layer 244 is described in more detail with respect to Figure 7. In some embodiments, the inert layer 246 is made of silicon or other suitable material. In some embodiments, the inert layer 246, the spacer member 280, and the sealing member 290 are all made of the same material (e.g., monolithically formed from a silicon wafer). In an exemplary embodiment, the inert layer 246, the spacer member 280, and the sealing member 290 are formed from a double silicon-on-insulator (SOI) wafer.

[0071] The spacer member 280 is shown to include an intermediate layer inserted between two peripheral layers. In an exemplary embodiment, the intermediate layer and the inert layer 246 comprise two silicon layers of a double SOI wafer, with the peripheral layers located on either side of the intermediate layer, which includes a silicon oxide layer. In this embodiment, the encapsulant member 290 and the spacer member 280 are formed by etching the surface of the double SOI wafer opposite the working portion 242. The oxide layer plays a role in controlling or stopping the etching process once, for example, by removing the entire intermediate layer forming the spacer member 280 within a region separating the spacer member 280 and the encapsulant member 290. Such a process provides precise control over both the width and thickness of the spacer member 280 and the encapsulant member 290.

[0072] As can be understood, the size of the sealing member 290 may contribute to the resonant frequency of the working beam 240. A larger amount of material placed at or near the end of the working beam 240 generally results in a lower resonant frequency of the working beam. Furthermore, such a larger amount of material will affect the initial curvature of the working beam 240 induced by the pressurized fluid in contact with the working beam 240. Thus, the desired size of the sealing member 290 influences the selection of various other designs of the working beam 240. Such design selections are described in more detail with respect to Figure 7A. In some embodiments, the sealing member 290 is sized based on the dimensions of the orifice 260. In some embodiments, the sealing member 290 is substantially cylindrical and has a diameter about 1.5 times the diameter of the orifice 260. For example, in one embodiment, the sealing member 290 has a diameter of about 90 microns if the orifice 260 has a diameter of about 60 microns. Such a configuration facilitates alignment between the sealing member 290 and the orifice 260 so that when the sealing member 290 contacts the valve seat 270, it completely covers the orifice 260. In another embodiment, the sealing member 290 is sized to have a surface area about twice that of the orifice 260 (for example, the spacer member 280 may have a diameter of about 150 microns, and the orifice 260 has a diameter of about 75 microns). Such an embodiment provides a greater tolerance for alignment between the sealing member 290 and the orifice 260, making it easier to create a seal between the valve seat 270 and the sealing member 290. In another embodiment, the diameter of the sealing member 290 may be 2, 2.5, 3, 3.5, or 4 times the diameter of the orifice 260. In various embodiments, the ratio of the length of the orifice 260 to its diameter may be in the range of 1:1 to 15:1. The ratio may influence the shape, size, and / or volume of the fluid droplets ejected through the orifice and may vary depending on the specific application.

[0073] Advantageously, the gap 324 between the spacer member 280 and the sealing member 290 creates a separation volume 326 between the working beam 240 and the orifice plate 250. The separation volume 326 prevents squeeze film damping of vibrations of the working beam 240. In other words, insufficient separation between the orifice plate 250 and the working beam 240 leads to drag forces resulting from the fluid that must enter and exit the separation volume 326 as the working beam 240 opens and closes the orifice 260. By having a larger separation volume created via the spacer member 280, such drag forces are reduced, and therefore the working beam 240 is more susceptible to vibrations at higher frequencies.

[0074] Continuing to refer to Figure 6, the orifice plate 250 comprises a base layer 252 and an intermediate layer 254. For example, in one embodiment, the base layer 252 comprises a silicon layer and the intermediate layer 254 comprises a silicon oxide layer. In the embodiment shown, a portion of the intermediate layer 254 adjacent to the orifice 260 is removed, and the first portion of the valve seat 270 is placed directly on the base layer 252, while the second portion of the valve seat 270 is placed on the intermediate layer 254. In another embodiment, it should be understood that the intermediate layer 254 extends all the way to the boundary of the orifice 260, and the valve seat 270 is placed on the intermediate layer 254. In yet another embodiment, the portion of the intermediate layer 254 to be removed may have a cross-section equal to or larger than the cross-section of the valve seat 270 so that the valve seat 270 is fully placed on the base layer 252.

[0075] Depending on the importance of the spatial relationship between the spacer member 280 and the valve seat 270, the attachment of the spacer member 280 to the orifice plate 250 may be carried out in a manner that allows for precise control of the resulting distance between the actuation beam 240 and the orifice plate 250. As shown, the spacer member 280 is attached to the orifice plate 250 using an adhesive layer 256. In various embodiments, a precise amount of epoxy adhesive (e.g., SU-8, polymethyl methacrylate, silicone, etc.) is applied to an intermediate layer 254, on which the combination of the spacer member 280 and the actuation beam 240 is then placed. The adhesive is then cured to form an adhesive layer 256 with a precisely controlled thickness. For example, in some embodiments, the bottom surface of the spacer member 280 is substantially aligned with the top surface of the valve seat 270. When the actuation beam 240 is in its initial position, any desired relationship between such surfaces can be obtained to produce a proper seal between the sealing member 290 and the valve seat 270. In various embodiments, the adhesive layer 256 and the valve seat 270 may be formed from the same material (e.g., SU-8) in a single photolithography process.

[0076] In various embodiments, once the actuation beam 240 and the orifice plate 250 are attached to each other via adhesive layer 256 (for example, to form a microvalve 230), another adhesive layer 248 is applied to the periphery of the actuation beam 240. The input fluid manifold 210 is attached to the actuation beam 240 using another adhesive layer 248. A structural layer 222 (or interposer 222b) may be placed on the input fluid manifold 210 and connected to it via a second adhesive layer 225. In some embodiments, the other adhesive layer 248 and the second adhesive layer 225 may contain the same material as adhesive layer 256.

[0077] In the embodiment shown with respect to Figure 6, the microvalve 230 includes a sealing structure 500 comprising various components, thereby forming a seal that separates the orifice 260 from the volume 502 adjacent to the actuation beam 240. In the embodiment shown, the sealing structure 500 comprises a sealing member 290 and a valve seat 270. As described herein, the actuation beam 240 is configured such that the orifice-facing surface 504 of the sealing member 290 contacts the upper surface of the valve seat 270 to form a seal at the interface between the valve seat 270 and the sealing member 290. The seal separates the orifice 260 from the volume 502 and allows minimal fluid to leak from the injection assembly 200 when no electrical signal is applied to the actuation beam 240. Several alternatives to the sealing structure 500 are described herein in detail. In another embodiment, the valve seat 270 may be omitted so that the surface of the sealing structure 500 facing the orifice is in contact with the orifice plate 250 in order to fluidly seal the orifice 260.

[0078] Referring here to Figure 7A, a more detailed diagram of the working beam 240 according to an exemplary embodiment is shown, and the diagram is not to scale. As shown, the working beam 240 comprises an inert layer 246, a tuning layer 244, a barrier layer 400, a first electrode section 402, a working section 242, a second electrode section 404, and a passivation structure 406. As can be understood, in various other embodiments, the working beam 240 may comprise more or fewer layers.

[0079] In some embodiments, the tuning layer 244 is placed directly on the inert layer 246. The tuning layer 244 generally functions as an adhesive layer to facilitate the deposition of other layers as described herein. Furthermore, as described herein, the thickness of the tuning layer 244 may play a significant role in determining the overall curvature of the working beam 240 when the working beam 240 is in its initial position. Generally speaking, the tuning layer 244 is configured to have a predetermined regulating stress such that, in the closed position, the sealing member 290 of the working beam 240 contacts and applies force to the valve seat 270 in order to fluidly seal the orifice 260. In some embodiments, in the absence of an electrical signal, the predetermined regulating stress is configured to curve the working beam 240 toward the orifice 260 such that, in the absence of the valve seat 270, the sealing member surface of the sealing member 290 is positioned at a predetermined distance (e.g., 2 microns) below the lower surface of the spacer member 280. For example, the tuning layer 244 may be placed under compressive stress as a result of the deposition of other layers as described herein. Therefore, a thicker tuning layer 244, when in its initial position, causes the working beam 240 to curve more towards the orifice 260. In one exemplary embodiment, the tuning layer 244 is made of silicon dioxide.

[0080] The barrier layer 400 acts as a barrier against the diffusion of materials contained in the piezoelectric layer 414 into the tuning layer 244. If left unchecked, such migration would result in harmful mixing effects between the constituent materials within the layer, negatively impacting performance. In various embodiments, the barrier layer 400 is composed of, for example, zirconium dioxide. As shown, the first electrode section 402 comprises an adhesive layer 408 and a first electrode 410. The adhesive layer 408 facilitates the deposition of the first electrode 410 on the barrier layer 400 and prevents the diffusion of substances within the first electrode 410 to other layers. In various embodiments, the adhesive layer 408 is composed of titanium dioxide. The first electrode 410 may be composed of platinum, gold, rubidium, or any other suitable material to provide a conductive path for electrical signals sent to the working section 242. In some embodiments, the first electrode section 402 is provided only in a select portion of the working beam 240. For example, the first electrode portion 402 may be located in close proximity to and / or within the electrical connection portion 294.

[0081] The operating portion 242 may be formed from one or more layers of any suitable piezoelectric material. In the embodiment shown, the active portion comprises a growth template layer 412 and a piezoelectric layer 414. The growth template layer 412 functions as a seed layer to promote the growth of the piezoelectric layer 414 having a desired texture (e.g., {001} crystal structure and corresponding texture) to ensure maximum piezoelectric response. In some embodiments, the growth template layer 412 is composed of lead titanate. The piezoelectric layer 414 may be composed of any suitable material, for example, lead zirconate titanate (PZT).

[0082] The piezoelectric layer 414 may be deposited using any method, for example, by utilizing vacuum deposition or sol-gel deposition techniques. In some embodiments, the piezoelectric layer 414 may have a thickness in the range of about 1 to 6 microns (e.g., 1, 2, 3, 4, 5, or 6 microns) and is configured to produce a deflection of about 10 microns at the end of the working beam 240 when an electrical signal is applied thereto. A deflection of 10 microns (for example, so that the surface of the sealing member 290 is separated from the valve seat 270 by a slightly less than that amount) may be sufficient to form a droplet on the orifice 260 of the desired size. In some embodiments, the piezoelectric layer 414 has a piezoelectric constant (d31 value) of about 140 to 160 pm / V. This value may allow the appropriate deflection of the working beam 240 to be generated by electrical signals sent to the first electrode portion 402 and the second electrode portion 404.

[0083] As shown, the second electrode portion 404 is positioned on the working portion 242. In various embodiments, the second electrode portion 404 is configured similarly to the first electrode portion 402 described herein. Thus, the application of voltage to the first electrode portion 402 and / or the second electrode portion 404 induces strain in the piezoelectric layer 414, bending the entire working beam 240 away from the orifice plate 250. By applying periodic control signals to the first and second electrode portions, the periodic cycle of the working beam 240 generates droplets ejected from the orifice 260 at a desired frequency. Figure 7A shows the first electrode portion 402 and the second electrode portion 404 overlapping each other, but elsewhere, the first electrode portion 402 and the second electrode portion 404 do not have to overlap. This can limit or prevent electron leakage between the first electrode portion 402 and the second electrode portion 404, which could damage the piezoelectric layer 414 or cause an electrical short circuit.

[0084] In various embodiments, the electrodes included in the first electrode section 402 and the second electrode section 404 are deposited in a non-annealing state. As a result, the electrodes are deposited in a substantially compressed state, which affects the overall curvature of the working beam 240 when in its initial position. The deposition mode of the piezoelectric layer 414 may affect the compressed state of the electrodes. For example, in some situations, the piezoelectric layer 414 is deposited (e.g., by vapor deposition technique) and then cured at a predetermined temperature (e.g., about 700°C), and the curing may anneal the electrodes 410 and remove the compressed state. Such removal affects the overall balance of stress in the working beam 240, which alters its initial curvature. Therefore, it may be beneficial to use a low-temperature deposition process for the piezoelectric layer 414 (e.g., a low-temperature sol-gel deposition process or a plasma-enhanced chemical vapor deposition process) to prevent stress reversal within the electrodes. In various embodiments, the second electrode section 404 may be annealed at a higher temperature than the first electrode section 402, for example, to generate a predetermined regulating stress in the tuning layer 244.

[0085] The material shown in Figure 7A may extend substantially over the entire length of the working beam 240. Therefore, there is overlap between the electrode portions 402 and 404 and the reservoir formed by the microvalve 230. In various embodiments, the fluid contained within the reservoir is conductive and / or corrosive to the materials forming the first electrode portion 402 and the second electrode portion 404. Therefore, it is preferable to separate the electrode portions 402 and 404 from the reservoir to prevent the fluid contained within the reservoir from coming into contact with the electrode portions 402 and 404.

[0086] In this regard, the passivation structure 406 is configured to perform such separation. In the embodiment shown, the passivation structure 406 comprises a dielectric layer 416, an insulating layer 418, and a barrier layer 420. The barrier layer 420 may be made of silicon nitride and functions as a diffusion barrier to water molecules and ions contained in the fluid to prevent corrosion of the electrode portions 402 and 404. In some embodiments, the insulating layer 418 comprises a silicon dioxide layer having a compressive stress that substantially balances the tensile stress in the barrier layer 420. The dielectric layer 416 may be made of aluminum oxide to prevent oxidation of another layer contained within the working beam 240. In some embodiments, another metal layer is placed on top of the barrier layer 420. For example, the metal layer may be made of talinum oxide or any other suitable chemical-resistant metal to further enhance the protective properties of the passivation structure 406. In certain embodiments, the barrier layer 420 may be formed of Teflon® or parylene. In another embodiment, at least a portion of the working beam 240, i.e., the structure formed by the layers shown in Figure 7A, may be covered or overcoated with a Teflon® layer or a parylene layer. Such an overcoat can prevent microcracks from forming within the layers of the working beam 240. In yet another embodiment, the overcoat may comprise a metallic layer, such as a tantalum layer or a palladium layer.

[0087] The addition of the passivation structure 406 can significantly affect the initial positioning of the working beam 240. This is because the passivation structure 406 is offset from the compression neutral axis 422 of the working beam 240. As shown, the neutral axis 422 is within the inert layer 246, which means that the electrode section 404 and the passivation structure 406 are furthest from it within the working beam 240. If this is the case, the tensile or compressive stresses induced in such layers will significantly affect the initial curvature of the working beam 240. Therefore, the thickness of the tuning layer 244 is selected based on the structure of the various constituent layers of the passivation structure 406.

[0088] Figure 7B is a front cross-sectional view of the working beam 240, showing the arrangement of each layer comprising the working beam 240 according to an exemplary embodiment and not to scale. As shown, the working beam 240 comprises an inert layer 246, a tuning layer 244, and a barrier layer 400, as described with respect to Figure 7A. The first electrode portion 402 comprises an adhesive layer 408 (e.g., titanium dioxide) disposed on the barrier layer 400, and a conductive layer or electrode 410 (e.g., platinum, gold, rubidium, etc.) disposed thereon. The first electrode portion 402 is configured to have a width smaller than the width of the barrier layer 400 such that the end of the electrode portion 402 perpendicular to the longitudinal axis of the working beam 240 is located inside the end of the barrier layer 400 in the same direction.

[0089] The working portion 242, comprising the seed layer 412 and the piezoelectric layer 414, is conformally positioned on the first electrode portion 402 such that it extends beyond the lateral end of the first electrode portion 402 and contacts the barrier layer 400. In this way, the piezoelectric layer completely surrounds or surrounds at least a portion of the first electrode portion 402 that overlaps with or is adjacent to the second electrode portion 404. The second electrode portion 404 comprises an adhesive layer 403 (e.g., titanium) and a conductive layer 405 (e.g., platinum, gold, rubidium, etc.). In some embodiments, the second electrode portion 404 may comprise only the conductive layer 405, which is directly positioned on the piezoelectric layer 414 (i.e., the adhesive layer 403 is omitted). Since the actuarial portion 242 overlaps with and extends beyond the end of the first electrode portion 402, the actuarial portion effectively electrically isolates the first electrode portion 402 from the second electrode portion 404 to prevent electron leakage and current migration that could be detrimental to the performance of the actuarial beam 240.

[0090] The passivation structure 406 conformally coats the exposed portions of the other layers 246, 244, 400, 402, 242, and 404. However, the bottom surface of the inert layer 246 does not need to be coated with the passivation structure 406. The passivation structure 406 may comprise a dielectric layer 416, an insulating layer 418, a barrier layer 420, and a top passivation layer 424. The barrier layer 420 may be made of silicon nitride and acts as a diffusion barrier to water molecules and ions contained in the fluid to prevent corrosion of the electrode portions 402 and 404. However, silicon nitride is generally under tensile stress once deposited on the remaining layers. The insulating layer 418 is configured to balance such tensile stress. For example, in some embodiments, the insulating layer 418 comprises a silicon dioxide layer having a compressive stress that substantially balances the tensile stress in the barrier layer 420. In various embodiments, the barrier layer 420 is located beneath the insulating layer 418. The dielectric layer 416 may consist of aluminum oxide, titanium oxide, zirconium oxide, or zinc oxide to prevent oxidation of other layers contained within the working beam 240. Thus, the passivation structure 406 works to prevent both corrosion and oxidation—two major sources of defects caused by the presence of fluids—in the working beam 240, and thus ensure the long-term performance of the microvalve 230. Furthermore, the top passivation layer 424 is located on top of the barrier layer 420 and may comprise a Teflon® layer or a parylene layer. Such an overcoat can prevent microcracks from forming within the layers of the working beam 240 and can also prevent the underlying layers from plasma discharging (for example, the embedded layer may be exposed in subsequent manufacturing operations). In certain embodiments, the top passivation layer 424 may comprise a metal layer, such as a tantalum layer or a palladium layer. In some embodiments, another metal layer is located on top of the barrier layer 420. For example, the metal layer may be composed of talinum oxide or any other suitable chemical-resistant metal to further enhance the protective properties of the passivation structure 406.

[0091] The injection assemblies, microvalves, and related components described with respect to Figures 8-12 may be implemented according to any of the embodiments described above. Referring here to Figure 8, a cross-sectional view of a sealing structure 800 for a microvalve according to an exemplary embodiment is shown. For example, the sealing structure 800 may be an example of the sealing structure 500 described with respect to Figure 6. As shown, the working beam 802 includes a cantilevered section 804. The cantilevered section 804 may extend from a base section that is positioned on a spacer member. The spacer member may be positioned on an orifice plate 812 that includes an orifice 814. The cantilevered section 804 extends from the base section toward the orifice 814 such that its overlapping portion 806 overlaps with the orifice 814.

[0092] The sealing structure 800 comprises a sealing member 808 positioned in the overlapping portion 806 and a valve seat 810 positioned on the orifice plate 812. The sealing member 808 extends toward the orifice 814 such that its surface 816 facing the orifice contacts the upper surface 822 of the valve seat 810. The valve seat 810 surrounds the orifice 814 and defines an opening 818. In the embodiment shown, the opening 818 is aligned with the orifice 814. In other words, the opening 818 and the orifice 814 define a fluid outlet having a substantially smooth and defined surface. In various embodiments, the valve seat 810 is formed of a suitable material, for example, SU-8. In another embodiment, the valve seat 810 may be formed of silicon. As described herein, the working beam 802 may be configured to have a slight curvature or bias toward the orifice 814 in its initial position, such that the surface 816 facing the orifice is pressed into the valve seat 810 to form a seal that separates the orifice 814 from the volume 820 located in the vicinity of the working beam 802.

[0093] In the embodiments shown, the orifice 814 is cylindrical. In another embodiment, the orifice 814 may have any other suitable shape (e.g., star-shaped, square, rectangular, polygonal, elliptical, etc.). The valve seat 810 is substantially annular and has an inner diameter equal to or substantially equal to the diameter of the orifice 814. The valve seat 810 has an outer diameter greater than its inner diameter. The sealing member 808 is formed as a substantially cylindrical column or support having a diameter between the inner and outer diameters of the valve seat 810. In the embodiments shown, the diameter of the sealing member 808 is closer to the inner diameter than the outer diameter of the valve seat 810. The size of the sealing member 808 contributes to the resonant frequency of the working beam 802 (e.g., by its overall weight, and therefore by influencing the overall piezoelectric response of the working beam 802). Therefore, in some embodiments, the diameter of the sealing member 808 is close to the inner diameter to produce a desired resonant frequency, given the size of the valve seat 810. However, naturally, the thickness of the valve seat 810 (i.e., the difference between the inner and outer diameters of the valve seat 810) may vary radially in various other embodiments, so that the overall positioning of the outer edge of the sealing member 808 relative to the valve seat 810 may change.

[0094] Referring now to Figure 9, a cross-sectional view of the sealing structure 900 according to an exemplary embodiment is shown. The sealing structure 900 shares features with the sealing structure 800 described with respect to Figure 8. That is, Figure 9 incorporates common reference numerals to indicate that such similar components are included.

[0095] As shown, in the sealing structure 900, the coating 902 is positioned on the upper surface 822 of the valve seat 810. In various embodiments, the coating 902 is a hydrophobic elastic material, such as CYTOP®, Teflon®, polydimethylsiloxane (PDMS), or any other suitable hydrophobic or lipophilic material. The hydrophobicity of the coating 902 promotes the dispersion of water droplets on the valve seat 810 and prevents the fusion of fine particulate matter on the upper surface 822. In other words, the coating 902 increases the long-term durability of the sealing structure 900. Furthermore, the coating 902 can increase the elasticity or conformity of the valve seat 810, facilitating the formation of a seal at the interface between the surface 816 facing the orifice and the upper surface 822. In some embodiments, the coating 902 may be formed from a conforming material, such as gold.

[0096] Referring here to Figure 10, a cross-sectional view of the sealing structure 1000 according to an exemplary embodiment is shown. The sealing structure 1000 shares features with the sealing structure 800 described with respect to Figure 8. That is, Figure 10 incorporates common reference numbers to indicate that such similar components are included. As shown in Figure 10, in the sealing structure 1000, the coating 1002 is positioned around the inner surface of the fluid outlet defined by the orifice 814 and the opening 818. In some embodiments, the coating 1002 may consist of a hydrophobic material, e.g., CYTOP®, Teflon®, PDMS, or any other suitable hydrophobic or oleophilic material. The hydrophobicity of the coating 1002 facilitates the formation and movement of droplets within the orifice 814 when the working beam 802 is activated (e.g., as a result of an electrical signal being applied to it).

[0097] In some embodiments, the sealing structure may comprise a combination of coatings 902 and 1002 as described with respect to Figures 9 and 10. In other words, the sealing structure may comprise both a coating covering the inner surface of the fluid outlet and a coating on the upper surface 822. Advantageously, such an implementation provides hydrophobicity within the fluid outlet and the upper surface 822.

[0098] Referring here to Figures 11 and 12, cross-sectional views of sealing structures 1100 and 1200 according to exemplary embodiments are shown. Sealing structures 1100 and 1200 share components with sealing structure 800 described with respect to Figure 8 and include similar reference numbers to indicate the incorporation of such similar components.

[0099] As shown in Figure 11, the sealing structure 1100 differs from the sealing structure 800 in that it includes a sealing member 1102 having a larger diameter than the sealing member 808 described with respect to Figure 8. Thus, the side surface 1104 of the sealing member 1102 is closer to the outer diameter than to the inner diameter of the valve seat 810. This arrangement provides a larger surface area to contact the upper surface 822 of the valve seat 810, forming the separating seal described herein. However, as can be understood, the larger size of the sealing member 1102 may contribute to the resonant frequency of the working beam 802 and other operating conditions of any incorporated injection assembly (e.g., droplet size, operating frequency, etc.).

[0100] As shown in Figure 12, the sealing structure 1200 differs from the sealing structure 1100 in that it includes a sealing member 1202 having a larger diameter than the sealing member 1102. The outer surface 1204 of the sealing structure 1200 is substantially aligned with the outer diameter of the valve seat 810. In other words, the diameter of the sealing member 1202 is aligned with the outer diameter of the valve seat 810 (for example, the outer diameter of + They are substantially equal (within 10%). Such arrangements provide a larger surface area for forming a separating seal, with the understanding that such modifications may otherwise affect the performance aspects of any incorporated injection assembly (e.g., operating frequency). In another embodiment, the diameter of the sealing member 1202 may be larger than the outer diameter of the valve seat 810. In some embodiments, silicone black may be formed on the surface of the sealing member 1102 or 1202 facing the orifice, thereby enhancing the fluid sealing of the sealing member to the valve seat 810.

[0101] Referring now to Figure 13, a cross-sectional view of a microvalve sealing structure 1300 according to an exemplary embodiment is shown. As shown, the cantilevered portion 1304 of the working beam 1302 extends toward the orifice 1318 in the orifice plate 1316. The overlapping portion 1306 of the cantilevered portion 1304 overlaps with the orifice 1318. The sealing structure 1300 includes a sealing member 1308 positioned in the overlapping portion 1306 and extending toward the orifice 1318. In various embodiments, the sealing member 1308 is molded to correspond to the orifice 1318. For example, in various embodiments, both the sealing member 1308 and the orifice 1318 are substantially cylindrical, and the orifice 1318 has a smaller diameter than the sealing member 1308.

[0102] The sealing structure 1300 further comprises a stopper 1310 positioned on the surface 1322 of the sealing member 1308 facing the orifice. The stopper 1310 may be made of a suitable material, for example, SU-8, PDMS, or any other suitable material. As shown, the stopper 1310 comprises a narrow portion 1312 attached to the surface 1322 facing the orifice and a wider portion 1314 extending from the narrow portion 1312. The narrow portion 1312 and the wider portion 1314 may be substantially cylindrical so that the stopper 1310 forms a substantially top-hat shaped structure. In various embodiments, the wider portion 1314 has a larger cross-sectional area than the narrow portion 1312.

[0103] The orifice-facing surface 1324 of the stopper 1310 includes a projection 1326 molded to correspond to the orifice 1318. The projection 1326 fits into the orifice 1318 and is aligned with the orifice 1318 so that a seal is reliably formed when the orifice-facing surface 1324 contacts the orifice plate 1316. In Figure 13, the stopper 1310 is shown to include a portion 1320 positioned on the orifice-facing surface 1322 and a remaining portion 1328 positioned on the orifice plate 1316. The stopper 1310 includes portion 1320 and the remaining portion 1328 at an intermediate stage of its construction. In various embodiments, after the construction of the stopper 1310 is complete, the stopper 1310 is a single structure that extends continuously between the orifice-facing surfaces 1322 and 1324.

[0104] Similar to the working beam 240 described with respect to Figures 5A-B, the working beam 1302 may be configured to have an initial curve or bias, with the surface 1324 facing the orifice in contact with the orifice plate 1316, and the projection 1326 fitting into the orifice 1318 to form a seal at the interface between the stopper 1310 and the orifice plate 1316. In other words, the working beam 1302 may apply a downward force, forming a seal as a result of direct contact between the stopper 1310 and the orifice plate 1316. The projection 1326 ensures a minimum gap at the interface and forms a seal.

[0105] Referring now to Figure 14, a cross-sectional view of a microvalve sealing structure 1500 according to an exemplary embodiment is shown. As shown, the cantilevered portion 1504 of the working beam 1502 extends toward the orifice 1516 of the orifice plate 1514. The overlapping portion 1506 of the cantilevered portion 1504 overlaps with the orifice 1516. The sealing structure 1500 includes a sealing member 1508 positioned in the overlapping portion 1506 and extending toward the orifice 1516. In various embodiments, the sealing member 1508 is shaped to correspond to the orifice 1516. For example, in various embodiments, both the sealing member 1508 and the orifice 1516 are substantially cylindrical, and the orifice 1516 has a smaller diameter than the sealing member 1508.

[0106] The sealing structure 1500 also includes a valve seat 1512. The valve seat 1512 surrounds the orifice 1516 and aligns with the orifice 1516 to define an opening that defines a fluid outlet. In various embodiments, the valve seat 810 is formed of a suitable material, for example, SU-8. In another embodiment, the valve seat 810 may be formed of a non-suitable material, for example, glass or silicon. As shown, the sealing blade or projection 1510 extends from the surface 1518 of the sealing member 1508 that faces the orifice. The sealing blade 1510 may be molded to correspond to the outer circumference of the sealing member 1508. In some embodiments, the sealing blade 1510 is substantially annular and has inner and outer diameters that fit between the inner and outer diameters of the valve seat 1512. The sealing blade 1510 extends toward the upper surface 1520 of the valve seat 1512 and contacts the valve seat 1512 when the actuation beam 1502 is positioned in its initial position. The sealing blade 1510 provides the center point of the downward force supplied by the actuation beam 1502 so that a seal is formed at the interface between the tip of the sealing blade 1510 and the valve seat 1512. As shown in Figure 14, the sealing blade 1510 may have a knife-edge tip with a suitable tip radius (e.g., in the range of 0.1 to 1.0 microns). In another embodiment, the sealing blade 1510 or any other sealing blade as defined herein may have a flat or rounded tip.

[0107] Referring here to Figure 15, a cross-sectional view of a sealing structure 1600 according to an exemplary embodiment is shown. The sealing structure 1600 comprises components similar to the sealing structure 1500 described with respect to Figure 14, and includes similar reference numerals to indicate the incorporation of such similar components. The sealing structure 1600 differs from the sealing structure 1500 described with respect to Figure 14 in that the sealing structure 1600 comprises another sealing blade 1602. The other sealing blade 1602 may be concentric with the sealing blade 1510 and surround the sealing blade 1510 such that the sealing blades 1510 and 1602 form concentric circles that contact the upper surface 1520. In another embodiment, the sealing blades 1510 and 1602 may be non-concentric with the orifice or may have non-circular cross-sections (e.g., oval, elliptical, polygonal, asymmetric, etc.).

[0108] The additional sealing blade 1602 increases the contact area between the sealing member 1508 and the valve seat 1512. The increased contact area not only improves the quality of the seal formed at the interface between the valve seat 1512 and the sealing blades 1510 and 1602, but also makes the sealing structure 1600 more effective in handling any fine particulate matter that may enter between the sealing member 1508 and the valve seat 1512. Furthermore, the additional sealing blade 1602 improves the durability of the sealing structure 1600 because it acts as a backup point for contact with the valve seat 1512. In other words, if the sealing blade 1510 is destroyed at a point on a particular circumference, the additional sealing blade 1602 will nevertheless form a seal at that point, allowing the sealing structure 1600 to function.

[0109] Figure 16 is a bottom view of a sealing member 1614 of an operating beam (e.g., any of the operating beams defined herein) comprising a sealing structure 1650, according to an exemplary embodiment. The sealing member 1614 has a substantially cylindrical cross-section, as shown in Figure 16. In another embodiment, the sealing member 1614 may have any other preferred cross-section, e.g., a square, rectangular, star-ellipse, etc. The sealing structure 1650 comprises a first set 1610a of sealing blades that extend axially from the orifice-facing surface 1618 of the sealing member 1614 and are arranged concentrically on the orifice-facing surface. A first gap 1612a may be provided between each adjacent first sealing blade 1611a of the first set 1610a of sealing blades such that each of the first set 1610a of sealing blades resembles a segment of a first circle (e.g., an arc segment). As described with respect to the first set of sealing blades 1610a, the second set of sealing blades 1610b may be arranged concentrically inside the first set of sealing blades 1610a, with a second gap 1612b between each adjacent second sealing blade 1611b of the second set of sealing blades 1610b. Similarly, as described with respect to the first and second sets of sealing blades 1610a / b, the third set of sealing blades 1610c may be arranged concentrically inside the second set of sealing blades 1610b, with a third gap 1612c between each adjacent third sealing blade 1611c of the third set of sealing blades 1610b. In another embodiment, even more sets of sealing blades may be arranged concentrically on the surface 1618 of the orifice sealing member. The gaps 1612a / b / c between the sets of sealing blades 1610a / b / c may be staggered relative to each other, i.e., they do not overlap concentrically. This arrangement not only provides better sealing, but also allows for the capture of any particles (e.g., contaminants, photoresist particles, etc.) between the sealing blade sets 1610a / b / c.

[0110] Referring here to Figure 17, a flowchart of method 1700 for configuring a sealing structure for a microvalve, according to an exemplary embodiment, is shown. Method 1700 can be performed to configure the sealing structures 1500 and 1600 described with respect to Figures 14, 15, and 16. Method 1700 may include fewer or different steps, depending on the implementation.

[0111] In step 1702, an orifice plate having an orifice is provided. For example, in some embodiments, the orifice plate is formed from an SOI wafer (for example, by removing a portion of the wafer to form the orifice). In some embodiments, after the orifice is formed, a valve seat is placed in the orifice. The valve seat may surround the orifice and define an opening that is aligned with the orifice to form a fluid outlet. In step 1704, an operating beam is provided, comprising a sealing member having a surface facing the orifice. For example, as described herein, the operating beam may be formed by etching a portion of a double SOI wafer so that the spacer member and the sealing member are formed in a single manufacturing step. The surface of the sealing member may have a surface facing the orifice.

[0112] In step 1706, an etching-resistant material is deposited on the surface facing the orifice. The etching-resistant material (e.g., silicon dioxide or silicon nitride) differs in chemical composition from the sealing member of the working beam so that the etching-resistant material slows down the chemical process (e.g., etching) that removes portions of the sealing member. In step 1708, a portion of the etching-resistant material is etched so that the remaining portion of the etching-resistant material on the surface facing the orifice corresponds to the position and shape of the sealing blade (e.g., one or more sealing blades). For example, the remaining portion of the etching-resistant material covers only a portion of the surface of the sealing member. In some embodiments, the etching-resistant material may be substantially ring-shaped to generate annular sealing blades. In various embodiments, the etching-resistant material consists of silicon dioxide. That is, the layer of etching-resistant material can be deposited by chemical vapor deposition or any other preferred method. The layer of etching-resistant material may then be patterned using any preferred method (e.g., using an etching mask, photolithography, etc.). In some embodiments, multiple portions of the etching-resistant material are formed to facilitate the formation of multiple sealing blades. In another embodiment, the release layer (e.g., photoresist) may be deposited on the surface facing the orifice and patterned by photolithography to generate a shape or a plurality of shapes corresponding to the size and position of the sealing blade. The etching-resistant material may be placed on the release layer such that the etching-resistant material contacts the surface of the orifice sealing member in the patterned portions, but is located on the release layer at all other locations. The release layer may then be removed so that any portion of the etching-resistant material located on the release layer is removed along with it, leaving behind the patterned etching-resistant material corresponding to the position and shape of the sealing blade located on the surface facing the orifice.

[0113] In step 1710, the sealing member is etched isotropically for a first predetermined time. Isotropic etching (e.g., wet etching) may be configured to etch a portion of the sealing member beneath the etching-resistant material, for example, to form the tip of the sealing blade. In step 1712, before mounting the working beam to the orifice plate, the sealing member is etched anisotropically (e.g., a deep reactive ion etching process, e.g., a Bosch process) for a second predetermined time to remove a portion of the sealing member so that the remaining unetched portion forms the sealing blade. The second predetermined time may be modified to determine the height of the sealing blade. For example, the etching-resistant material can delay or completely prevent etching of the portion of the sealing member covered by the portion of the etching-resistant material. Thus, the exposed portion of the sealing member is removed at a faster rate than the portion covered by the portion of the etching-resistant material. Thus, a protrusion is formed beneath the etching-resistant material and constitutes the sealing blade. Etching may be performed for a time selected based on the desired length of the sealing blade. For example, the desired length may be selected based on the estimated durability of the resulting sealing blade. The estimated durability may depend at least in part on other dimensions of the sealing blade (e.g., radial thickness). In another embodiment, the sealing blade may be formed by other means, rather than providing an etching-resistant material and applying an etching solution to the surface of the sealing member. For example, the sealing blade may be formed using any suitable molding method.

[0114] In step 1714, in some embodiments, the etching-resistant material may be removed. For example, the etching-resistant material (e.g., silicon dioxide) may be removed by wet etching (e.g., buffered hydrofluoric acid etching) or a dry etching process. In some embodiments, method 1700 may also include anisotropically etching a portion of the working beam to form a sealing member and releasing the working beam from the substrate to form a cantilevered portion of the working beam. In step 1716, after the sealing blade is formed on the sealing member surface, the working beam is mounted on the orifice plate such that the sealing member surface is aligned with the valve seat positioned on the orifice plate. For example, a spacer member attached to the working beam may be positioned and mounted on the orifice plate such that the surface of the sealing member is aligned with the orifice. When the working beam is positioned in its initial position, the sealing member surface is aligned with the orifice such that the sealing blade is positioned to contact the upper surface of the valve seat.

[0115] Referring now to Figure 18, a cross-sectional view of a microvalve sealing structure 1800 according to an exemplary embodiment is shown. As shown, the cantilevered portion 1804 of the working beam 1802 extends toward the orifice 1816 of the orifice plate 1814. The overlapping portion 1806 of the cantilevered portion 1804 overlaps with the orifice 1816. The sealing structure 1800 includes a sealing member 1808 positioned in the overlapping portion 1806 and extending toward the orifice 1816. In various embodiments, the sealing member 1808 is shaped to correspond to the orifice 1816. For example, in various embodiments, both the sealing member 1808 and the orifice 1816 are substantially cylindrical, and the orifice 1816 has a smaller diameter than the diameter of the sealing member 1808.

[0116] As shown, the sealing member 1808 comprises a surface 1818 facing the orifice and a side surface 1822. A portion of the sealing member 1808 is removed at the corner between the surface 1818 facing the orifice and the side surface 1822. In various embodiments, the removed portion of the sealing member 1808 extends circumferentially around the entire sealing member 1808. Thus, the sealing member has a narrow portion 1824 at its end. The narrow portion may have a diameter approximately equal to the diameter of the orifice 1816. The sealing flap 1810 extends radially outward from the narrow portion 1824 on the surface 1818 facing the orifice. As shown, the sealing flap 1810 contacts the upper surface 1820 of the valve seat 1812 when the working beam 1802 is in the default position, forming a seal at the interface between the sealing member 1808 and the valve seat 1812. The sealing flap 1810 provides a compressible medium through which a seal can be formed. In another embodiment, the sealing flap may be provided on the inner rim of the valve seat 1812. In such an embodiment, the narrow portion 1824 of the sealing member 1808 may be configured to at least partially enter the opening defined by the valve seat 1812 and may engage with the sealing flap positioned on the inner rim of the valve seat 1812 to form a fluid seal.

[0117] Referring now to Figure 19, a flowchart of method 1900 for constructing a sealing structure for a microvalve, according to an exemplary embodiment, is shown. Method 1900 can be performed to construct the sealing structure 1800 described with respect to Figure 18. Method 1900 may include fewer or different steps, depending on the implementation.

[0118] In step 1902, an orifice plate having an orifice is provided. For example, in some embodiments, the orifice plate is formed from an SOI wafer (for example, by removing a portion of the wafer to form the orifice). In some embodiments, after the orifice is formed, a valve seat is placed in the orifice. The valve seat may surround the orifice and define an opening that is aligned with the orifice to form a fluid outlet. In step 1904, an operating beam is provided, comprising a sealing member having a surface and sides facing the orifice. For example, as described herein, the operating beam may be formed by etching a portion of a double SOI wafer so that the spacer member and the sealing member are formed in a single manufacturing step. The sealing member may be substantially cylindrical. The surface facing the orifice may comprise an end surface of the sealing member, and the sides may comprise a curved surface of the sealing member.

[0119] In step 1906, an etching-resistant material is deposited across the entire surface facing the orifice. The etching-resistant material (e.g., silicon dioxide or silicon nitride) differs in chemical composition from the sealing material of the working beam so that the etching-resistant material slows down the chemical process (e.g., etching) that removes the sealing material. In various embodiments, the etching-resistant material consists of silicon dioxide. That is, the layer of etching-resistant material can be deposited by chemical vapor deposition or any other preferred method.

[0120] In step 1908, the sealing member is selectively etched (e.g., with an etching solution, e.g., TMAH or KOH) such that a portion of the sealing member on the side surface beneath the etching-resistant material is removed, and the etching-resistant material extends over the removed portion of the sealing member to form a sealing flap. For example, the etching solution may be applied to the end of the sealing member near the surface of the sealing member so that a portion of the sealing member not covered by the etching-resistant material (e.g., at a corner separating the sealing member surface from the side) is selectively etched and removed. The remaining portion of the etching-resistant material may then form a sealing flap. Thus, the sealing flap may form a conforming layer that allows little or no material to be placed on either side thereof and can form a seal on various surfaces. In another embodiment, the etching-resistant material may be removed after step 1908, and a separately manufactured sealing flap formed from a conforming material (e.g., PDMS) may be placed on the surface facing the orifice.

[0121] In step 1910, the working beam is mounted to the orifice plate such that a portion of the sealing flap extends over the orifice. For example, a spacer member attached to the working beam may be positioned and mounted on the orifice plate such that the surface of the sealing member aligns with the orifice. In some embodiments, the sealing member is substantially centered with respect to the orifice. As a result, the sealing flap may extend radially beyond the inner diameter of the valve seat so that a seal can be formed between the valve seat and the sealing flap when the working beam is in its initial position.

[0122] Referring now to Figure 20, a flowchart of Method 2000 for constructing a microvalve according to an exemplary embodiment is shown. By performing Method 2000, any of the microvalves described herein can be constructed. Method 2000 may include fewer or different steps, depending on the implementation.

[0123] In step 2002, an orifice plate having an orifice is provided. For example, in some embodiments, the orifice plate is formed from an SOI wafer (for example, by removing a portion of the wafer to form the orifice). In some embodiments, after the orifice is formed, a valve seat is placed in the orifice. The valve seat may surround the orifice and define an opening that is aligned with the orifice to form a fluid outlet. In step 2004, an operating beam is provided, comprising a sealing member having a surface and sides facing the orifice. For example, as described herein, the operating beam may be formed by etching a portion of a double SOI wafer so that the spacer member and the sealing member are formed in a single manufacturing step. The sealing member may be substantially cylindrical. The surface facing the orifice may comprise an end surface of the sealing member.

[0124] In step 2006, a portion of the sealing structure is formed on at least one of the sealing member and the orifice plate. For example, in some embodiments, a portion of the sealing structure member comprises a valve seat component on the surface of the orifice plate. The valve seat may surround the orifice plate and define an opening that is aligned with the orifice to form a fluid outlet. The valve seat may be made of a suitable material, such as SU-8, and may be deposited using any preferred method (e.g., spin coating or spray coating).

[0125] In some embodiments, a portion of the sealing structure is formed on the surface of the sealing member facing the orifice. This may require the steps described with respect to Figures 14, 17, and 18, and constitutes a stopper, at least one sealing blade, or a sealing flap. As understood, any combination of these structures may be used to constitute a portion of the sealing member. In certain embodiments, multiple portions of the sealing structure may be formed. For example, in addition to the components on the sealing member surface of the sealing member or valve seat (e.g., fitting structure, sealing blade, and / or sealing flap), the valve seat may be formed on the orifice plate. In certain embodiments, a portion of the sealing structure may be formed on a side surface of the sealing structure (e.g., side surface 1822 as described with respect to Figure 18). For example, in one embodiment, the sealing member is configured to fit into a fluid outlet consisting of a valve seat and an orifice plate, and the components of the sealing structure extend radially outward from the side surface. The components may contact the upper surface of the valve seat to form a seal that separates the orifice from the volume adjacent to the working beam.

[0126] In step 2008, the working beam is attached to the orifice plate, and the sealing member overlaps the orifice, forming a seal that separates the orifice from the volume adjacent to the working beam. For example, a spacer member attached to the working beam may be positioned and attached to the orifice plate such that its surface facing the orifice aligns with the orifice. In some embodiments, the sealing member is substantially centered with respect to the orifice. As a result, a portion of the sealing member formed in step 2006 may contact either the orifice plate or the valve seat on it when the working beam is in its initial position.

[0127] Referring here to Figure 21, a cross-sectional view of a sealing member 2100 of a microvalve according to an exemplary embodiment is shown. The sealing member 2100 may be the sealing member 808 provided in the sealing structure 800 described with respect to Figure 8, or any exemplary embodiment of any of the sealing structures described herein. As shown, the sealing member 2100 is substantially cylindrical and has a diameter 2102. The diameter 2102 may be selected based on the size of the orifice in the orifice plate. For example, in some embodiments, the diameter 2102 is about 150% of the diameter of the orifice (for example, the orifice may have a diameter of 60 microns, and the diameter 2102 may be 90 microns).

[0128] Referring here to Figure 22, a cross-sectional view of a valve seat 2200 of a microvalve according to an exemplary embodiment is shown. The valve seat 2200 may be a valve seat 810 provided in the sealing structure 800 described with respect to Figure 8, or any exemplary embodiment of any of the sealing structures described herein. As shown, the valve seat 2200 is annular and comprises an inner diameter 2202 and an outer diameter 2204. The inner diameter 2202 and the outer diameter 2204 may define a range that includes the diameter of the sealing member. For example, in an embodiment in which the sealing member 2100 described with respect to Figure 21 is used in conjunction with the valve seat 2200, the diameter 2102 may be selected to be larger than the inner diameter 2202. In some embodiments, the diameter 2102 is between the inner diameter 2202 and the outer diameter 2204. In some embodiments, the diameter 2102 is equal to the outer diameter 2204, and the microvalve is configured such that the sealing member 2100 is substantially aligned with the valve seat 2200 so that the outer surface of the sealing member is substantially coplanar with the valve seat 2200. In some embodiments, the diameter 2102 is greater than the outer diameter 2204 so that the outer edge of the sealing member 2100 protrudes from the valve seat in the assembled microvalve.

[0129] Referring now to Figure 23, a cross-sectional view of a microvalve sealing structure 2300 according to an exemplary embodiment is shown. As shown, the cantilevered portion 2304 of the working beam 2302 extends toward the orifice 2316 of the orifice plate 2314. The overlapping portion 2306 of the cantilevered portion 2304 overlaps with the orifice 2316. The sealing structure 2300 includes a sealing member 2308 positioned in the overlapping portion 2306 and extending toward the orifice 2316. In various embodiments, the sealing member 2308 is shaped to correspond to the orifice 2316. For example, in various embodiments, both the sealing member 2308 and the orifice 2316 are substantially cylindrical, and the orifice 2316 has a smaller diameter than the sealing member 2308.

[0130] The sealing structure 2300 also includes a valve seat 2312. The valve seat 2312 surrounds the orifice 2316 and aligns with the orifice 2316 to define an opening that defines a fluid outlet. In various embodiments, the valve seat 2312 is formed of a suitable material, such as photoresist (e.g., SU-8). As shown, a plurality of sealing blades or projections 2310 extend from the orifice-facing surface 2318 of the sealing member 2308. The sealing blades 2310 may be shaped to correspond to the outer circumference of the sealing member 2308 (for example, concentrically arranged on the orifice-facing surface 2318). In some embodiments, the sealing blades 2310 are substantially annular and have inner and outer diameters that fit between the inner and outer diameters of the valve seat 2312.

[0131] As shown in Figure 23, the sealing layer 2320 may be located on the valve seat 2312. The sealing layer 2320 may comprise, for example, a metal (e.g., gold or platinum) layer or any other suitable layer. In various embodiments, a plurality of recesses 2322 may be formed on the sealing layer 2320. The plurality of recesses 2322 may be formed, for example, by an etching process and may be located in positions corresponding to the positions of a plurality of sealing blades 2310. In certain embodiments, the plurality of recesses 2322 are formed by cold forging by repeatedly striking a plurality of sealing blades 2310 on the sealing layer 2320 (e.g., by periodic application of an electrical signal to an operating beam 2302). The sealing blades 2310 extend toward the sealing layer 2320 and, when the operating beam 2302 is in its initial position, contact the base of the corresponding recess 2322. The spacing between adjacent sealing blades 2310, and the distance between the surface 2318 facing the orifice and the orifice plate 2314, may be configured to push small particles P (e.g., dust, photoresist fragments, etc.) out of the seal formed between the sealing blades 2310 and the valve seat 2312, for example, toward and toward the orifice 2316 and toward the outward direction of the orifice 2316. Furthermore, fitting multiple sealing blades 2310 into corresponding recesses 2322 may facilitate the formation of a better fluid seal between the sealing member 2308 and the valve seat 2312. In certain embodiments, a filter (e.g., 5, 10, 15, or 20 microns) may be located upstream of the fluid manifold in a partition provided within the injection assembly with a microvalve comprising the sealing structure 2300, to filter dust or other fine particulate matter from the fluid.

[0132] In certain embodiments, the valve seat placed on the orifice plate may be formed from silicon, and the sealing layer may be formed from silicon oxide or silicon nitride. For example, Figure 24 illustrates a process 2400 used to provide a sealing layer 2420 on a valve seat 2412. In step 1, a silicon valve seat 2412 is provided on an orifice plate 2414, and an orifice 2416 is defined thereon. The orifice plate 2414 may comprise any of the orifice plates defined herein. The valve seat 2412 is formed from silicon and may be deposited thereon, for example, by a silicon epitaxial growth process, followed by photolithography patterning and etching, or it may comprise a portion of silicon (e.g., a silicon ring) placed around the orifice 2416. The sealing layer 2420 (e.g., a silicon oxide or silicon nitride sealing layer) is placed on the valve seat 2412. The sealing layer 2420 may be deposited using a physical deposition process (e.g., a chemical vapor deposition process or a plasma-enhanced vapor deposition process).

[0133] In step 2, the multiple openings 2422 are defined at predetermined locations within the silicon oxide encapsulation layer 2420 such that the encapsulation layer 2420 forms multiple silicon oxide rings or silicon nitride rings 2421. The multiple openings 2422 may be formed by photolithography and etching processes (e.g., using buffered hydrofluoric acid or a dry plasma etching process) to expose the surface of the silicon valve seat 2412 at predetermined locations. In step 3, the silicon valve seat 2412 may be selectively etched at the multiple openings 2422 using an etching solution that selectively etches silicon (e.g., using potassium hydroxide or tetramethylammonium oxide etching solution or a dry plasma etching process) to form multiple recesses 2424 within the silicon valve seat 2412. In some embodiments, the multiple recesses 2424 may correspond to multiple encapsulation blades (e.g., encapsulation blades 2310) positioned on the surface facing the orifice of the working beam (e.g., working beam 2302). In another embodiment, the multiple rings 2421 may function as sealing blades so that the multiple sealing blades may be excluded from the working beam. Process 2400 describes a silicon valve seat 2412 having a silicon oxide or silicon nitride sealing layer 2420 on which it is placed, but in another embodiment, the valve seat 2412 and / or sealing layer 2420 may be formed from any other suitable material, e.g., negative photoresist (e.g., SU-8, polymethyl methacrylate, etc.), PDMS, silicone rubber, etc., and may be formed using photolithography and etching processes (e.g., any combination of the processes described herein) or mechanically placed on which it is placed. Furthermore, in another embodiment, the steps of process 2400 may be used to form a sealing member having multiple rings on the tip of the working beam.

[0134] Referring here to Figure 25, a cross-sectional view of a microvalve 2530 provided in an injection assembly (e.g., injection assemblies 100, 200, 200b) according to an exemplary embodiment is shown. An input fluid manifold 2510 is connected to the microvalve 2530. As shown, the input fluid manifold 2510 and the microvalve 2530 define a reservoir 3000 configured to hold a volume of pressurized fluid received from an external fluid supply (e.g., via carriers 202, 202b). In various embodiments, the pressurized fluid held in the reservoir 3000 is a combination of ink and another fluid in a liquid state.

[0135] In various embodiments, the input fluid manifold 2510 may be pre-formed before mounting to the microvalve. In some embodiments, the input fluid manifold 2510 may be formed from a glass body having any suitable thickness (e.g., about 500 microns). In another embodiment, the input fluid manifold 2510 may be formed from silicon. In some embodiments, the input fluid manifold 2510 may be connected to the top surface of the actuation beam 2540 (e.g., any of the actuation beams 240, 240b described herein) at the base portion 2542 of the actuation beam 2540, which is positioned and fixed on the spacer member 2580, via a first adhesive structure 2548. The first adhesive structure 2548 may comprise a plurality of adhesive rings similar to those described with respect to Figure 4A or 4B. The adhesive may include SU-8 or any other suitable adhesive and may be applied to the bottom surface of the input fluid manifold 2510 and / or the top surface of the actuation beam 2540. In another embodiment, the first adhesive structure 2548 may be formed from silicon or glass and connected to the working beam 2540 by glass frit, solder, adhesive, fusion bonding, eutectic bonding, or stiction. The electrode 2504 is located in a via defined in the base portion of the working beam 2540 and is electrically coupled to a piezoelectric layer defined within the working beam 2540. As described herein, the via may correspond to a channel or opening 2512 defined within the input fluid manifold 2510 and may be filled with a sealing agent.

[0136] The microvalve 2530 also includes an orifice plate 2550 attached to the working beam 2540 via a spacer member 2580. As shown in Figure 25, the second adhesive structure 2556 may be similar to the first adhesive structure 2548 and may comprise multiple rings or loops of adhesive material (e.g., SU-8). In some embodiments, multiple grooves or teeth 2582 may be defined on the bottom surface of the spacer member 2580 facing the orifice plate 2550. The adhesive contained in the adhesive structure 2556 may penetrate the grooves 2582 to provide substantially higher bonding strength with the spacer member 2580 compared to embodiments in which the grooves 2582 are not defined.

[0137] In some embodiments, the support beam 2558 may extend from the orifice plate 2550 toward the spacer member 2580 and may be configured to define a separation distance between the orifice plate 2550 and the spacer member 2580, thereby allowing the working beam 2540 to also function as a guard ring to prevent solvent solutions (e.g., contained in the fluid used within the microvalve 2530) from penetrating below the spacer member 2580 during use of the microvalve 2530. In certain embodiments, the support beam fitting layer 2559 may be positioned at the tip of the support beam 2558 in close proximity to the spacer member 2580. The support beam fitting layer 2559 may comprise a gold layer or any other suitable fitting layer. In some embodiments, the second bonding structure 2556 may also be formed from silicon or glass and may be connected to the working beam spacer member by glass frit, solder, adhesive, fusion bonding, eutectic bonding, or stiction.

[0138] The orifice plate 2550 is substantially planar and includes an orifice 2560 extending between its surfaces. The valve seat 2570 may be located on the surface of the orifice plate 2550 facing the working beam 2540 around the rim of the orifice 2560. The valve seat 2570 defines an internal opening 2571 substantially aligned with the orifice 2560, forming an outlet for the pressurized fluid supplied to the microvalve 2530. In some embodiments, a valve seat fitting layer 2572 (e.g., a gold layer) may be located on the surface of the valve seat 2570 facing the working beam 2540.

[0139] In some embodiments, the orifice plate 2550 may be substantially flat, for example, having a flatness with a coefficient of variation of less than 3 microns over a length and width of at least 15 mm of the orifice plate 2550, such that the orifice plate 2550 is substantially free from warping or bending. Furthermore, the orifice plate 2550 may have any preferred thickness. In some embodiments, the orifice plate 2550 may have a thickness in the range of 30 to 90 microns (30, 40, 50, 60, 70, 80, 90, or 100 microns). In another embodiment, the orifice plate 2550 may have a thickness in the range of 100 to 900 microns (e.g., 100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800, or 900 microns). Thicker orifice plates 2550 may facilitate the realization of a flatter orifice plate.

[0140] The working beam 2540 comprises a base portion 2542 positioned on the spacer member 2580 and a cantilevered portion 2544 extending from the base portion toward the orifice 2560. The working beam 2540 is substantially similar to the working beams 240 and 240b, except for the differences described below herein. The sealing member 2590 extends from a portion of the working beam 2540 that overlaps with the orifice 2560. In some embodiments, the sealing member 2590 is configured to have a shape substantially corresponding to the shape of the orifice 2560 (e.g., a cylindrical shape).

[0141] The sealing blade 2592 extends from the orifice-facing surface of the sealing member 2590 toward the valve seat 2570. The sealing blade 2592 may be shaped to correspond to the outer circumference of the sealing member 2590. In some embodiments, the sealing blade 2592 is substantially annular and has inner and outer diameters that fit between the inner and outer diameters of the valve seat 2570. The sealing blade 2592 extends toward the upper surface of the valve seat 2570 and contacts the valve seat 2570 when the actuation beam 2540 is in the closed position. The sealing blade 2592 provides the center point of the downward force supplied by the actuation beam 2540 so that a seal is formed at the interface between the tip of the sealing blade 2592 and the valve seat 2570.

[0142] Further magnification, Figure 26 is an enlarged view of a portion of the microvalve 2530 indicated by arrow A in Figure 25. As shown in Figure 25, the tip of the sealing blade 2592 is substantially flat and, in some embodiments, may be coated with a sealing blade compatibility layer (e.g., a gold layer). Figure 26 shows the tip of the sealing blade coated with resist 2591, which acts as an etching mask to enable selective etching of the sealing member 2590 to form the sealing blade 2592, which is then removed. In some embodiments, the resist width X2 of resist 2591 is in the range of 1 to 15 microns (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 microns), and as a result, the sealing blade width X1 of the sealing blade 2592 is in the range of 8 to 12 microns (e.g., 8, 9, 10, 11, or 12 microns). The inner cross-sectional dimension Y1 (e.g., inner diameter) of the resist may be in the range of 20 to 100 microns (e.g., 20, 30, 40, 50, 60, 70, 80, 85, 90, 95, or 100 microns), and the outer cross-sectional dimension Y2 (e.g., outer diameter) of the resist may be in the range of 30 to 120 microns (e.g., 30, 40, 50, 60, 70, 80, 90, 100, 105, 110, 115, or 120 microns). The outer cross-sectional dimension Y3 (e.g., outer diameter) of the sealing member 2590 may be in the range of 80 to 140 microns (e.g., 80, 90, 100, 110, 120, 125, 130, 135, or 140 microns).

[0143] The inner cross-sectional dimension Z1 of the valve seat 2570 (for example, the diameter of the opening 2571 defined in the valve seat 2570) may be in the range of 20 to 80 microns (for example, 20, 30, 40, 50, 55, 60, 65, 70, 75, or 80 microns), and the outer cross-sectional dimension Z4 of the valve seat 2570 (for example, the outer diameter) may be in the range of 100 to 160 microns (for example, 100, 110, 120, 130, 140, 145, 150, 155, or 160 microns). The first radial distance Z2 from the rim of the opening 2571 defined in the valve seat 2570 to the edge of the valve seat fitting layer 2572 may be in the range of 1 to 4 microns (e.g., 1, 2, 3, or 4 microns), and the second radial distance Z3 from the inner diameter edge of the sealing blade 2592 to the rim of the opening 2571 defined in the valve seat 2570 may be in the range of 7 to 15 microns (e.g., 7, 8, 9, 10, 11, 12, 13, 14, or 15 microns).

[0144] The larger cross-section of the sealing blade 2592 than the inner cross-sectional dimension Z1 allows for axial displacement between the opening 2571 and the inner diameter edge of the sealing blade 2592, further enabling sealing of the opening 2571 defined within the valve seat 2570. For example, Figure 27 shows a cross-sectional view of the sealing blade 2592 cut along line BB in Figure 26. As shown in Figure 27, the sealing blade 2592 is axially displaced from the opening 2571, but can still fluid-seal the area on the valve seat 2570 surrounding the opening 2571, thereby preventing fluid leakage through the opening 2571 when the working beam 2540 is in its closed position (e.g., initial position).

[0145] In some embodiments, a portion of the adhesive structure used to bond the spacer member of the working beam to the orifice plate may extend beyond the radially inner edge of the spacer member. For example, Figure 28A is a side cross-sectional view of a portion of a microvalve 2630 according to one embodiment. The microvalve 2630 comprises an orifice plate 2650. The working beam 2640 is positioned on the orifice plate 2650. The base portion 2642 of the working beam 2640 is positioned on a spacer member 2680 which is connected to the orifice plate 2650 via a support beam 2658 (e.g., support beam 2558) and a second adhesive structure 2656 (e.g., SU-8 structure). The second adhesive structure 2656 may have a thickness in the range of 2 to 20 microns (e.g., 2, 3, 4, 5, 10, 12, 14, 16, 18, or 20 microns). Multiple grooves or tooth profiles 2682 may be defined on the surface of the spacer member 2680 facing the orifice plate 2650. The second adhesive structure 2656 penetrates the multiple grooves 2682 as described herein and forms a strong bond with the spacer member 2680. In various embodiments, the multiple grooves 2682 may have a cross-sectional dimension (e.g., width) of about 5 to 10 microns and may be spaced apart at intervals of 5 to 10 microns. In another embodiment, the multiple grooves 2682 may be omitted.

[0146] As described herein, the input fluid manifold 2610 is joined to the actuation beam 2640 on the base portion 2642 of the actuation beam 2640 via a first bonding structure 2661. The first bonding structure 2661 may comprise a plurality of rings made of an adhesive (e.g., SU-8) or a structural material, such as glass or silicon. At least one of the rings of the first bonding structure 2661 is positioned opposite the second bonding structure 2656 to balance the torsional stress applied by the movement of the cantilevered portion 2644 of the actuation beam 2640 away from the orifice plate 2650, for example. In some embodiments, the first bonding structure 2661 and the second bonding structure 2656 may be formed from the same material (e.g., SU-8, silicon, glass, etc.). In some embodiments, a plurality of grooves may also be defined on the surface of the spacer member 2680 to facilitate the bonding of the first bonding structure 2661, or on any other surface where the adhesive is placed.

[0147] The second adhesive structure 2656 may also extend radially beyond the radially inner edge of the spacer member 2680, such that a portion of the second adhesive structure 2656 has a predetermined length X (for example, in the range of 5 to 10 microns) located below the cantilevered portion 2644 of the working beam 2640. The extension of the second adhesive structure 2656 may be axially spaced by an axial distance Y from the bottom surface of the cantilevered portion 2644 facing the orifice plate 2650, which may be equal to the thickness of the spacer member 2680.

[0148] In some embodiments, the fluid used with the microvalve 2630 described herein or any other microvalve may include a solvent that can dissolve or expand the adhesive used to form the first adhesive structure 2661 and the second adhesive structure 2656. In some embodiments, the first adhesive structure 2661 and / or the second adhesive structure 2656 may be formed using an inorganic material, such as silicon or glass that does not react with the solvent. In another embodiment, a thin coating of solvent-resistant organic, inorganic, or hybrid / inorganic material can be placed on the exposed surface of the microvalve 2630 to protect the first adhesive structure 2661 and the second adhesive structure 2656.

[0149] For example, Figure 28B shows an enlarged view of a portion of the microvalve 2630 indicated by arrow B in Figure 28A. For example, a coating 2686 having a thickness in the range of 5 to 100 nm (5, 10, 20, 30, 40, 50, or 100 nm) may be coated on the microvalve 2630. In some embodiments, the coating may be deposited using an atomic layer deposition (ALD) process. The coating 2686 may be formed from any suitable material, such as aluminum oxide, titanium oxide, zinc oxide, or any other suitable material, or a combination thereof.

[0150] In some embodiments, any of the microvalves described herein may also include a bumper to prevent overshoot of the working beam provided in the microvalve. For example, Figure 29 is a side cross-sectional view of a microvalve 2730 according to another embodiment. The microvalve 2730 has components similar to those described with respect to the microvalve 2530. The microvalve 2730 includes a working beam 2740 substantially similar to the working beam 2540, but also includes a bumper 2791 extending from the cantilevered portion 2744 of the working beam 2740 toward the orifice plate 2550. In another embodiment, the bumper 2791 may be located on the orifice plate 2550 and extend from there toward the cantilevered portion 2744 of the working beam 2740. The bumper 2791 may be located in any preferred position, for example, midway between the spacer member 2580 and the sealing member 2590. The bumper 2791 may be formed from the same material (e.g., silicon) as the orifice plate 2550 or the actuation beam 2740. The bumper 2791 may be configured to prevent overshoot of the cantilevered portion of the actuation beam 2740 by restricting the movement of the actuation beam 2740.

[0151] In some embodiments, the microvalve may include a mechanism to restrict the movement of the working beam by guiding it back to its initial position. For example, Figure 30 is a side cross-sectional view of a microvalve 3520 according to another embodiment. The microvalve 3520 includes an orifice plate 3510, in which an orifice 3560 is defined. The working beam 3540 is positioned on the orifice plate 3510 and spaced therefrom via a spacer 3580. A sealing member 3524 is positioned on the overlapping portion 3549 of the working beam 3540 and configured to contact a valve seat 3522 positioned around or on the orifice plate 3510 overlapping the orifice, and is configured to seal the orifice 3560 in the initial position of the working beam 3540. The overlapping portion 3549 is located at the tip of the working beam 3540 and overlaps with the orifice 3560. The finger 3517 is positioned on a support column 3515 located on the orifice plate 3510 and extends toward the actuation beam 3540 so as to overlap with at least the overlapping portion 3549 of the actuation beam 3540. The finger 3517 may be configured to push the overlapping portion 3549 of the actuation beam 3540 toward the valve seat 3522 so as to ensure that a fluid seal is formed between the sealing member 3524 and the valve seat 3522 in the initial position of the actuation beam 3540.

[0152] The finger 3517 may be configured to have rigidity such that, in response to a charge applied to the actuation beam 3540, it overcomes the cantilever portion of the actuation beam 3540 by bending or curving away from the orifice 3560. When the charge is removed, the finger 3517 may push the cantilever portion back toward the orifice 3560. In another embodiment, a biasing member 3519 (e.g., a helical spring, disc spring, beryllium-copper spring, or fitting member) is operably connected to the finger 3517 and configured to bias when a charge is applied to the actuation beam 3540. When the charge is removed, the biasing member 3519 can push the overlapping portion 3549 back toward the orifice 3560. In certain embodiments, the biasing member 3519 may be operably connected to the overlapping portion 3549 so that the finger 3517 is repelled.

[0153] The embodiments described above refer to a cantilevered operating beam, but in another embodiment, the microvalve may simply have a supported operating beam. For example, Figure 31 is a side cross-sectional view of a microvalve 3620 according to another embodiment. The microvalve 3620 comprises an orifice plate 3610 defining an orifice 3660. An operating beam 3640 is positioned on the orifice plate 3610, with a first axial end 3646a of the operating beam 3640 positioned on the orifice plate 3610 via a first spacer member 3680a and spaced away from the orifice plate 3610. A second axial end 3646b of the operating beam 3640 is positioned on the orifice plate 3610 via a second spacer member 3680 and spaced away from the orifice plate 3610. The spacer members 3680a / b are connected to the orifice plate 3610 via corresponding adhesive layers 3656a / b. The working beam 3640 includes a bend 3648 configured to bend toward or away from the orifice plate 3610. The bend 3648 includes an overlapping portion 3649 that overlaps with the orifice 3660 (for example, located midway between the shaft ends 3646a / b). The sealing member 3624 is positioned in the overlapping portion 3649 of the working beam 3640 and is configured to contact a valve seat 3672 positioned around the orifice 3660 or on the orifice plate overlapping the orifice, thereby sealing the orifice 3660 in the initial position of the working beam 3640. In various embodiments, the valve seat 3672 may be formed from the same material as the adhesive layers 3656a / b (for example, formed in the same manufacturing process). Since the overlapping portion 3649 may be centered on the working beam 3640, the bending of the bent portion 3648 around the shaft end 3646a / b can move the sealing member 3624 toward and away from the valve seat 3672 without any angle being given to it (i.e., the sealing surface of the sealing member 3624 may remain substantially parallel to the valve seat 3672).Furthermore, if the orifice plate 3610 warps, the operating beam 3640 also warps accordingly, and as a result, the sealing member 3624 can remain in the same position and orientation relative to the valve seat 3672. This allows for a better seal to be formed between the sealing surface of the sealing member 3624 and the valve seat 3672, regardless of any warping or curvature of the orifice plate 3610.

[0154] In some embodiments, the microvalve includes an orifice plate having a first surface and a second surface, the orifice plate having an orifice extending from the first surface to the second surface; an operating beam positioned spaced apart from the orifice plate, the operating beam comprising a base portion and a cantilever portion, the base portion being a predetermined distance from the orifice plate, the cantilever portion extending from the base portion toward the orifice, the overlapping portion of which overlaps with the orifice, and the operating beam being movable between a closed position and an open position; and a sealing structure comprising a sealing member positioned on the overlapping portion of the cantilever portion, wherein when the operating beam is in the closed position, the cantilever portion is positioned such that the sealing structure seals the orifice and closes the microvalve.

[0155] In some embodiments, the working beam comprises a layer of piezoelectric material, and the working beam is movable between a closed position and an open position in response to an electrical signal applied to the piezoelectric material. In some embodiments, when no electrical signal is applied to the piezoelectric material, the microvalve is in the closed position. In some embodiments, when a reverse-polarity electrical signal is applied to the piezoelectric material, the microvalve approaches the closed position or the force holding the microvalve in the closed position increases.

[0156] In some embodiments, the sealing structure includes a stopper positioned on the surface of the sealing member, the stopper comprising a first portion attached to the surface of the sealing member and a second portion positioned on the first portion in close proximity to the orifice plate, the second portion having a larger cross-sectional area than the first portion. In some embodiments, the stopper is in direct contact with the orifice plate when there is no electrical signal. In some embodiments, the stopper is composed of a bisphenol A novolac glycidyl ether-based photoresist. [In some embodiments, each of the sealing member, the first portion, and the second portion is substantially cylindrical.]

[0157] In some embodiments, the sealing structure further comprises a valve seat surrounding the orifice, the valve seat overlapping the orifice to define an opening that defines a fluid outlet. In some embodiments, the sealing member comprises a sealing member surface facing the orifice, the sealing member surface being substantially parallel to the upper surface of the orifice plate, the sealing member surface being displaced by a certain distance from the valve seat when the working beam is in the closed position, and a first sealing blade extending a distance from the sealing member surface toward the orifice plate, the first sealing blade surrounding the entire perimeter of the orifice.

[0158] In some embodiments, the sealing member and orifice plate are substantially cylindrical, the orifice is cylindrical with a first diameter, and the sealing member is cylindrical with a second diameter greater than the first diameter. In some embodiments, the first sealing blade is annular and has a first outer diameter greater than the first diameter and less than the second diameter. In some embodiments, the first outer diameter is closer to the first diameter than the second diameter.

[0159] In some embodiments, the sealing member further comprises a second sealing blade surrounding a first sealing blade, the second sealing blade having a second outer diameter greater than the first outer diameter but smaller than the second outer diameter, such that an annular gap is formed between the first and second sealing blades. In some embodiments, the first and second sealing blades are formed of the same material as the rest of the sealing member.

[0160] In some embodiments, the orifice and sealing member are substantially cylindrical, and the valve seat is annular and surrounds the orifice. In some embodiments, the orifice has a first diameter, and the sealing member has a second diameter that is larger than the first diameter. In some embodiments, the valve seat has an outer diameter between the first and second diameters. In some embodiments, the valve seat has an outer diameter that is approximately equal to or greater than the second diameter.

[0161] In some embodiments, the sealing member further comprises a constriction located at its end, the constriction defining the surface of the sealing member facing the orifice, and a sealing flap extending outward from the constriction so as to overlap with the upper surface of the valve seat when the working beam is in the closed position.

[0162] In some embodiments, the inner surfaces of the valve seat and the orifice are substantially aligned with each other to form a fluid outlet, and the microvalve further comprises a coating positioned on the inner surface of the fluid outlet. In some embodiments, the coating covers at least one of the upper surface of the valve seat facing the sealing member, or the sealing member surface of the sealing member facing the valve seat. In some embodiments, the coating comprises polydimethylsiloxane.

[0163] In some embodiments, a method for constructing a microelectromechanical system (MEMS) microvalve includes providing an orifice plate with an orifice, providing an operating beam having a spacer member and an attached sealing member, forming a portion of a sealing structure on either the orifice plate or the sealing member, and after forming the portion of the sealing structure, attaching the operating beam to the orifice plate, wherein the sealing member is aligned with the orifice, and the sealing structure forms a seal in the closed position of the operating beam that separates the orifice from a volume adjacent to the operating beam.

[0164] In some embodiments, forming a portion of the sealing structure includes arranging a valve seat on an orifice plate surrounding an orifice, and the method further includes forming an additional portion of the sealing structure on the orifice-facing surface of the sealing member.

[0165] In some embodiments, an additional portion of the sealing structure comprises one or more sealing blades, and forming the additional portion of the sealing structure includes depositing an etching-resistant material on a surface facing the orifice; etching a portion of the etching-resistant material such that the remaining portion of the etching-resistant material on the surface facing the orifice corresponds to the position and shape of one or more sealing blades; isotropically etching the sealing member for a first predetermined time such that the isotropic etching is configured to etch a portion of the sealing member beneath the etching-resistant material, thereby forming one or more sealing blades; and removing the remaining portion of the etching-resistant material from the surface facing the orifice.

[0166] In some embodiments, the method also includes anisotropically etching the sealing member for a second predetermined time to remove a portion of the sealing member before removing the etching-resistant material, wherein the remaining portion forms a higher sealing blade, and then removing the etching-resistant material. In some embodiments, the etching-resistant material is silicon dioxide.

[0167] In some embodiments, the additional portion of the sealing structure comprises a sealing flap substantially parallel to the orifice plate extending outward from the surface facing the orifice, and forming the additional portion of the sealing structure includes depositing an etching-resistant material on the surface facing the orifice and selectively etching the sealing member, thereby removing a portion of the sealing member on the circumferential surface of the sealing member beneath the etching-resistant material, and the etching-resistant material extending over the removed portion of the sealing member to form a sealing flap.

[0168] In some embodiments, the method of claim 27 further includes anisotropically etching a portion of the working beam to form a sealing member, and releasing the working beam from the substrate to form a cantilevered portion of the working beam.

[0169] In some embodiments, the injection assembly comprises a valve body having an orifice plate with a plurality of orifices extending through it; a plurality of microvalves, each of which has a spacer member positioned on the orifice plate and displaced from the corresponding orifice; an operating beam, the operating beam having a base portion positioned on the spacer member and a cantilever portion extending from the base portion toward the corresponding orifice, the overlapping portion of which overlaps with the corresponding orifice, and the operating beam being configured to move between a closed position in which the cantilever portion is bent toward the orifice and an open position in which the cantilever portion is bent toward the orifice; and a sealing structure attached to the overlapping portion and having a sealing member extending toward the corresponding orifice; and a fluid manifold connected to each of the plurality of microvalves and defining the fluid reservoir of each microvalve.

[0170] In some embodiments, the working beam comprises a layer of piezoelectric material, and the working beam is movable between a closed position and an open position in response to an electrical signal applied to the piezoelectric material, and when no electrical signal is applied to the layer of piezoelectric material, the microvalve is in the closed position.

[0171] In some embodiments, the sealing structure includes a stopper disposed on the surface of the sealing member, the stopper comprising a first portion attached to the surface of the sealing member and a second portion disposed in close proximity to the first portion by an orifice plate, the second portion having a larger cross-sectional area than the first portion.

[0172] In some embodiments, the sealing structure further comprises a valve seat positioned on an orifice plate adjacent to the orifice, the valve seat overlapping the orifice to define an opening that defines a fluid outlet.

[0173] In some embodiments, the sealing member comprises a sealing member surface facing the orifice, the sealing member surface being substantially parallel to the upper surface of the orifice plate, and the sealing member surface being displaced by a certain distance from the valve seat, and a first sealing blade extending a distance from the sealing member surface toward the orifice plate, the first sealing blade surrounding at least a portion of the orifice, and a portion of the first sealing blade being positioned slightly away from the outer circumference of the orifice. In some embodiments, the sealing member further comprises a second sealing blade surrounding the first sealing blade.

[0174] In some embodiments, the first sealing blade, the second sealing blade, and the valve seat are substantially annular in shape, the valve seat having an inner diameter and an outer diameter, and when the cantilevered portion is in the closed position, the entirety of the first and second sealing blades is positioned between the inner and outer diameters on the upper surface of the valve seat.

[0175] In some embodiments, the sealing member further comprises a constriction located at its end, the constriction defining the surface of the sealing member facing the orifice, and a sealing flap extending outward from the edge of the constriction on the surface of the sealing member, the sealing flap extending substantially parallel to the orifice plate and overlapping the upper surface of the valve seat.

[0176] In some embodiments, the microvalve comprises an orifice plate having a first surface and a second surface, the orifice plate having an orifice extending from the first surface to the second surface; an operating beam positioned spaced apart from the orifice plate, the operating beam comprising a base portion and a cantilever portion, the base portion being a predetermined distance from the orifice plate, the cantilever portion extending from the base portion toward the orifice, the overlapping portion overlapping with the orifice, and the operating beam being movable between a closed position and an open position; and a sealing structure positioned on the operating beam, the sealing structure comprising a sealing member positioned on the overlapping portion of the cantilever portion; and a stopper positioned on the surface of the sealing member, the stopper comprising a first portion attached to the surface of the sealing member and a second portion positioned adjacent to the orifice plate and on the first portion, the second portion having a larger cross-sectional area than the first portion; and the cantilever portion being positioned such that when the operating beam is in the closed position, the stopper seals the orifice and closes the microvalve.

[0177] In some embodiments, the microvalve includes an orifice plate having a first surface and a second surface, the orifice plate having an orifice extending from the first surface to the second surface, and an operating beam positioned spaced apart from the orifice plate, the operating beam comprising a base portion and a cantilever portion, the base portion being spaced a predetermined distance from the orifice plate, the cantilever portion extending from the base portion toward the orifice, the overlapping portion overlapping with the orifice, and the operating beam being movable between a closed position and an open position, and on the operating beam A sealing structure is provided, wherein the sealing structure is a valve seat surrounding an orifice, the valve seat surrounding the orifice and defining an opening that defines a fluid outlet; the sealing structure is provided, wherein the sealing structure is provided, wherein the sealing structure is provided, wherein the sealing structure is provided, wherein the sealing structure is provided, wherein the sealing structure is provided, wherein the sealing member extends the distance from the sealing member surface toward the orifice plate, the first sealing blade surrounds the entire perimeter of the orifice, and the first sealing blade is configured to contact the valve seat in the closed position in order to seal the orifice and close the microvalve. In some embodiments, the sealing member further comprises a second sealing blade surrounding the first sealing blade, the second sealing blade having a second outer diameter that is larger than the first outer diameter but smaller than the second outer diameter, and an annular gap is formed between the first sealing blade and the second sealing blade.

[0178] In some embodiments, the microvalve comprises an orifice plate having a first surface and a second surface, the orifice plate having an orifice extending from the first surface to the second surface; an operating beam positioned spaced apart from the orifice plate, the operating beam comprising a base portion and a cantilever portion, the base portion being a predetermined distance from the orifice plate, the cantilever portion extending from the base portion toward the orifice, the overlapping portion overlapping with the orifice, and the operating beam being movable between a closed position and an open position; and a sealing structure positioned on the operating beam, the sealing structure comprising a sealing member positioned on the overlapping portion of the cantilever portion, a constriction positioned at the merge end of the sealing member defining the surface of the sealing member facing the orifice, and a sealing flap extending outward from the constriction portion and configured to seal the orifice and close the microvalve when the operating beam is in the closed position.

[0179] As used herein, the terms "about" and "approximately" mean roughly ±10% of a given value. For example, about 0.5 includes 0.45 and 0.55, about 10 includes 9 to 11, and about 1000 includes 900 to 1100.

[0180] As used herein, terms such as “to connect,” “to link,” etc., mean that two members are joined to each other directly or indirectly. Such a connection may be fixed (e.g., permanent) or movable (e.g., removable or openable). Such a connection may be achieved by forming the two members, or the two members and any other intervening member, together as a single unit, or by attaching the two members, or the two members and any other intervening member, to each other.

[0181] References to the position of elements in this specification (e.g., “up,” “down,” “above,” “below,” etc.) are used simply to describe the orientation of the various elements in the figures. It should be noted that the orientation of the various elements may differ according to other exemplary embodiments, and such variations are intended to be covered by this disclosure.

[0182] The configuration and arrangement of elements shown in the exemplary embodiments are illustrative only. Although only a few embodiments of this disclosure are described in detail, a person skilled in the art reviewing this disclosure will readily understand that many modifications are possible (e.g., variations in the size, dimensions, structure, shape and proportions of various elements, parameter values, mounting arrangements, material applications, colors, orientations, etc.) without substantially departing from the novel teachings and advantages of the enumerated subject matter. For example, elements shown as integrally formed may consist of multiple parts or elements, the positions of elements may be reversed or otherwise altered, and the properties, number, or positions of individual elements may be changed or altered.

[0183] Furthermore, the term “exemplary” is used to mean that it serves as an example, illustration, or diagram. Any embodiment or design described herein as “exemplary” or “example” should not necessarily be construed as being preferable or advantageous to other embodiments or designs (and such terms are not intended to imply that such embodiments are necessarily exceptional or best examples). Rather, the use of the term “exemplary” is intended to illustrate the concept concretely. Accordingly, all such modifications are intended to be included within the scope of this disclosure. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of preferred embodiments and other exemplary embodiments without departing from the scope of the appended claims.

[0184] Without departing from the scope of the present invention, other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of various exemplary embodiments. For example, any element disclosed in one embodiment may be incorporated into or utilized in any other embodiment disclosed herein. Also, for example, the order or sequence of steps of any process or method may be changed or reordered according to another embodiment. Any means and function clauses are intended to encompass not only the structures described herein as performing the function described, but also their structural equivalents as well as equivalent structures. Without departing from the scope of the appended claims, other substitutions, modifications, changes, and omissions may be made in the design, operating configuration, and arrangement of preferred embodiments and other exemplary embodiments.

Claims

1. Microbulbs are An orifice plate having a first surface and a second surface, wherein the orifice plate has an orifice extending from the first surface to the second surface, An operating beam is positioned spaced apart from the orifice plate, the operating beam comprising a base portion and a cantilever portion, the base portion being separated from the orifice plate by a predetermined distance, the cantilever portion extending from the base portion toward the orifice, the overlapping portion overlapping with the orifice, and the operating beam being movable between a closed position and an open position. The sealing structure includes a sealing member disposed in the overlapping portion of the cantilever beam, When the operating beam is in the closed position, the cantilevered beam portion is positioned such that the sealing structure seals the orifice and closes the microvalve, the microvalve.

2. The microvalve according to claim 1, wherein the operating beam comprises a layer of piezoelectric material, and the operating beam is movable between the closed position and the open position in response to an electrical signal applied to the piezoelectric material.

3. The microvalve according to claim 1, wherein the sealing structure comprises a stopper disposed on the surface of the sealing member, the stopper comprising a first portion attached to the surface of the sealing member and a second portion disposed on the first portion in close proximity to the orifice plate, the second portion having a larger cross-sectional area than the first portion.

4. The microvalve according to claim 3, wherein the stopper is composed of a bisphenol A novolac glycidyl ether-based photoresist.

5. The microvalve according to claim 3, wherein each of the sealing member, the first portion, and the second portion is substantially cylindrical.

6. The microvalve according to claim 1, wherein the sealing structure further comprises a valve seat surrounding the orifice, and the valve seat overlaps with the orifice to define an opening that defines a fluid outlet.

7. The sealing member is A sealing member surface facing the orifice, wherein the sealing member surface is substantially parallel to the upper surface of the orifice plate, and the sealing member surface is displaced by a certain distance from the valve seat when the operating beam is in the closed position, The microvalve according to claim 6, comprising a first sealing blade that extends the distance from the surface of the sealing member toward the orifice plate, wherein the first sealing blade surrounds the entire periphery of the orifice.

8. The microvalve according to claim 7, wherein the sealing member and the orifice plate are substantially cylindrical, the orifice is cylindrical with a first diameter, and the sealing member is cylindrical with a second diameter greater than the first diameter.

9. The microvalve according to claim 8, wherein the first sealing blade is annular and has a first outer diameter that is greater than the first diameter and less than the second diameter.

10. The microvalve according to claim 6, wherein the inner surface of the valve seat and the inner surface of the orifice are substantially aligned with each other to form a fluid outlet, and the microvalve further comprises a coating disposed on the inner surface of the fluid outlet.

11. The microvalve according to claim 6, further comprising a suitable layer that covers at least one of the upper surface of the valve seat facing the sealing member, or the sealing member surface of the sealing member facing the valve seat.

12. The microvalve according to claim 11, wherein the conforming layer contains gold.

13. The injection assembly is A valve body comprising an orifice plate having multiple orifices that penetrate and extend through it, A plurality of microvalves, each of the plurality of microvalves is A spacer member is placed on the orifice plate and displaced from the corresponding orifice, An operating beam comprising a base portion disposed on the spacer member and a cantilever portion extending from the base portion toward the corresponding orifice, wherein the overlapping portion overlaps with the corresponding orifice, and the operating beam is configured to move between a closed position in which the cantilever portion is bent toward the orifice and an open position in which the cantilever portion is bent away from the orifice. A plurality of microvalves comprising a sealing structure having a sealing member attached to the overlapping portion and extending toward the corresponding orifice, An injection assembly comprising a fluid manifold connected to each of the plurality of microvalves and defining the fluid reservoir of each of the plurality of microvalves.

14. The injection assembly according to claim 13, wherein the operating beam comprises a layer of piezoelectric material, the operating beam is movable between the closed position and the open position in response to an electrical signal applied to the piezoelectric material, and when no electrical signal is applied to the layer of piezoelectric material, the microvalve is in the closed position.

15. The injection assembly according to claim 13, wherein the sealing structure comprises a stopper disposed on the surface of the sealing member, the stopper comprising a first portion attached to the surface of the sealing member and a second portion disposed in close proximity to the first portion by the orifice plate, the second portion having a larger cross-sectional area than the first portion.

16. The injection assembly according to claim 13, wherein the sealing structure further comprises a valve seat positioned on the orifice plate in close proximity to the orifice, and the valve seat overlaps with the orifice to define an opening that defines a fluid outlet.

17. The sealing member is The sealing member surface facing the orifice, wherein the sealing member surface is substantially parallel to the upper surface of the orifice plate, and the sealing member surface is displaced by a certain distance from the valve seat, The injection assembly according to claim 16, comprising: a first sealing blade extending the distance from the surface of the sealing member toward the orifice plate, wherein the first sealing blade surrounds at least a portion of the orifice such that a portion of the first sealing blade is positioned around the orifice, slightly away from it.

18. The injection assembly according to claim 17, wherein the sealing member further comprises a second sealing blade surrounding the first sealing blade.

19. Microbulbs are An orifice plate having a first surface and a second surface, wherein the orifice plate has an orifice extending from the first surface to the second surface, An operating beam is positioned spaced apart from the orifice plate, the operating beam comprising a base portion and a cantilever portion, the base portion being separated from the orifice plate by a predetermined distance, the cantilever portion extending from the base portion toward the orifice, the overlapping portion overlapping with the orifice, and the operating beam being movable between a closed position and an open position. A sealing structure disposed on the operating beam, wherein the sealing structure is A valve seat surrounding the orifice, wherein the valve seat surrounds the orifice and defines an opening that defines a fluid outlet, A sealing structure is disposed in the overlapping portion of the cantilever beam, A microvalve comprising a sealing structure, the first sealing blade extending the distance from the sealing surface of the sealing member toward the orifice plate, wherein the first sealing blade surrounds the entire periphery of the orifice and is configured to contact the valve seat in the closed position in order to seal the orifice and close the microvalve.

20. The microvalve according to claim 19, wherein the sealing member further comprises a second sealing blade surrounding the first sealing blade, the second sealing blade having a second outer diameter that is larger than the outer diameter of the first but smaller than the diameter of the second, and an annular gap is formed between the first sealing blade and the second sealing blade.

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