Patent Description:
Industrial and commercial applications, including medical equipment, are increasingly utilizing force sensors to determine applied forces. However, conventional force sensor designs cannot be integrated easily and cost-effectively into disposable blood pressure monitoring devices.

Applicant has identified a number of deficiencies and problems associated with conventional force sensors. Through applied effort, ingenuity, and innovation, many of these identified problems have been solved by developing solutions that are included in embodiments of the present disclosure, many examples of which are described in detail herein.

<CIT> discloses a membrane isolated, gel-filled force sensor.

<CIT> discloses a reusable fluid pressure transducer monitoring apparatus.

<CIT> discloses a pressure transducer apparatus with disposable dome.

<CIT> discloses a medical sensor assembly and mounting assembly therefor.

Systems, apparatuses, and methods (including, but not limited to methods of manufacturing and methods of packaging) are disclosed herein for providing a disposable blood pressure monitoring device having a miniature size force sensor package design with a gel-based coupling technology. In some embodiments, the miniature size force sensor package design provided herein solves the above problems by providing a coupling interface that enables the miniature size force sensor to be integrated easily and cost-effectively into various application areas and types of equipment, including disposable blood pressure monitoring devices.

According to an aspect of the present invention, there is provided a system for sensing a force applied by an external source in a fluid monitoring tube according to claim <NUM>.

Having described certain example embodiments of the present disclosure in general terms above, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale.

The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The detailed description and drawings show several embodiments which are meant to be illustrative of the disclosure. It should be understood that any numbering of disclosed features (e.g., first, second, etc.) and/or directional terms used in conjunction with disclosed features (e.g., front, back, under, above, etc.) are relative terms indicating illustrative relationships between the pertinent features.

It should be understood at the outset that although illustrative implementations of one or more aspects are illustrated below, the disclosed assemblies, systems, and methods may be implemented using any number of techniques, whether currently known or not yet in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, but may be modified within the scope of the appended claims.

While values for dimensions of various elements are disclosed, the drawings may not be to scale.

The word "example," when used herein, is intended to mean "serving as an example, instance, or illustration. " Any implementation described herein as an "example" is not necessarily preferred or advantageous over other implementations.

Generally, force sensors are used in a variety of applications such as, but not limited to, infusion pumps, ambulatory non-invasive pumps, occlusion detection, enteral pumps, load and compression sensing, variable tension control, and other application areas. Further, there is a continuous push from the market for reduction in size of the force sensors. Users in certain applications may need a force sensor which is small enough to fit into an application area and simultaneously provides an interface which is large enough for deployment. For instance, the disposable blood pressure monitoring market is a large volume market that exceeds volumes of <NUM> million pieces per year. In many instances, these disposable blood pressure monitoring devices must meet the specification and performance requirements of the BP22 standard for blood pressure transducers promulgated by the American National Standards Institute, Inc. , and the Association for the Advancement of Medical Instrumentation. However, the disposable blood pressure monitoring market is placing increasing pressure to provide low cost solutions for sterilized, disposable blood pressure monitoring devices.

Existing disposable blood pressure monitoring devices typically consist of laser trimmed pressure sensors packaged into a standard housing assembly. The standard housing assembly has luer locks to engage tubing and is transparent to allow visibility to the blood flow. The standard housing assembly further mounts the sensor and provides an electrical cable output. However, these disposable blood pressure monitoring devices are too expensive to satisfy the market demand for increasingly low cost solutions for sterilized, disposable blood pressure monitoring devices.

The disclosure solves these problems by describing unique designs for disposable blood pressure monitoring devices that replace the conventional laser trimmed ceramic plate design, which drives the costs of these devices, with a small force sensing die that incorporates deep reactive-ion etching (DRIE) processing to minimize the size of the force sensing assembly and thereby minimize the overall size of the blood pressure monitoring device. The disclosure further solves these problems by describing a specialized solution that adjusts the bridge output of the force sensing device to correct for offset and span temperature effects. The disclosure further solves these problems by describing a design that assembles the force sensing device into the housing without a glue joint by assembling a radial seal ring structure in the housing to engage the outer diameter of the gel ring on the force sensing device to seal the force sensing device into the housing. The disclosure further describes using one or more snap structures disposed between the base plate and the housing to retain the force sensing assembly (e.g., the force sensing device, gel ring, gel, signal conditioning circuitry, substrate, and wire bonds) in the housing and sandwich the electrical cables against wedge terminals mounted to the backside of the substrate (e.g., a printed circuit board (PCB)) using surface-mount technology (SMT). These wedge terminals may act as springs to engage the electrical cables and create the electrical connection to external devices.

In some embodiments, the disclosure describes multiple levels of assembly. The first level of assembly may be directed to the force sensing assembly (e.g., the force sensing device, gel ring, gel, signal conditioning circuitry, substrate, and wire bonds), which may be manufactured using a PCB panel having four wedge terminals SMT mounted to each position on the panel. The PCB panel may be a very high density panel to lower the unit costs (e.g., greater than <NUM> positions one panel, and possibly as many as <NUM>,<NUM> positions on one panel). The force sensing device may comprise a pressure range gauge sense die adhesively attached to the PCB substrate and wire bonded to the PCB. In some embodiments, the pressure range gauge sense die may be a one bar pressure range gauge sense die. A digitally controlled resistor network may be adhesively attached to the PCB and wire bonded to the PCB. A gel ring (e.g., a metal ring) may be adhesively attached to the PCB around the sense die and wire bonds and filled with a biocompatible room-temperature vulcanizing (RTV) material, such as silicone. The force sensing assembly then may be packaged into tape and reel packaging for delivery to the final assembly line.

Final assembly may involve picking the force sensing assembly from the tape and reel packaging and placing the force sensing assembly into the housing by pressing the gel ring into the mating hole in the fluid monitoring tube of the housing. This press fit may seal the force sensing assembly into the housing. In some embodiments, the seal may propagated by another element with compliance specifically to seal between the bore and the sensor gel ring. The backside of the force sensing assembly PCB may comprise four wedge terminals, which may be exposed, allowing the force sensing assembly to receive an electrical cable harness (e.g., a wire harness) with stripped electrical cables which may mate into grooves in the housing. The grooves in the housing may help to align the electrical cables to the terminals on the PCB. The base plate may engage the housing and press the electrical cables against the terminals on the PCB. This base plate may also support, and in some instances push on, the PCB to hold the gel ring into the housing. The blood pressure monitoring device may be held together by one or more snap structures in the plastic of the base plate engaging mating structures in the housing, or vice versa. The one or more snap structures may be tight enough to hold the assembly together and keep the electrical contacts engaged for life of product, which in some instances may be two years of shelf storage and <NUM> days of operating use.

<FIG>, <FIG>, <FIG>, and <FIG> illustrate an example top view, an example isometric view, an example cross-sectional view, and another example cross-sectional view A-A, respectively, of an example disposable blood pressure monitoring device <NUM> in accordance with some example embodiments described herein. The example disposable blood pressure monitoring device <NUM> may comprise any combination of components, structures, and features herein, including the addition, omission, or rearrangement of components, structures, and features. In some embodiments, the example disposable blood pressure monitoring device <NUM> may be a hardware device with embedded software configured to measure, detect, and transmit data (e.g., temperature, pressure, motion, and other suitable data). In some embodiments, the embedded software may be configured to run in an apparatus, device, or unit (e.g., firmware).

In some embodiments, as shown in <FIG>, <FIG>, <FIG>, and <FIG>, the example disposable blood pressure monitoring device <NUM> comprises a base plate <NUM> (e.g., a plastic base plate) attached (e.g., using one or more snap structures) to a housing <NUM> comprising a fluid monitoring tube, a luer lock <NUM>, and a luer lock fitting <NUM>. For example, the housing <NUM> comprises a snap structure configured to attach the housing <NUM> to the base plate <NUM> and retain the force sensing device <NUM> and optional signal conditioning circuitry in the housing <NUM>. In some embodiments, the one or more snap structures are disposed between the base plate <NUM> and the housing <NUM> to retain the force sensing assembly in the housing <NUM> and sandwich the one or more electrical cables <NUM> against one or more wedge terminals that may be SMT mounted to the second surface 112b (e.g., backside) of the substrate <NUM>. The one or more wedge terminals may act as springs to engage the one or more electrical cables <NUM> and create the electrical connection to external devices.

In some embodiments, the housing <NUM> may be optically transparent or near-transparent to allow for visual confirmation (e.g., by an imaging device or a user's eye) that no bubbles are present in the fluid in the fluid monitoring tube or that air bubbles have been cleared therefrom. In some embodiments, the base plate <NUM> may not be optically transparent or near-transparent. For example, the housing <NUM>, the base plate <NUM>, or both may be made of an optically transparent polymer or plastic.

In some embodiments, the example disposable blood pressure monitoring device <NUM> further comprises a force sensing assembly comprising a force sensing device <NUM> (e.g., comprising a force sensing die, a gel ring, and a biocompatible RTV material such as a silicone gel), optional signal conditioning circuitry, wire bonds, and a substrate <NUM> (e.g., a PCB). The substrate <NUM> comprises a first surface 112a (e.g., a top surface) and a second surface 112b (e.g., a bottom surface) opposite the first surface 112a. The force sensing device <NUM> is configured to be disposed on the first surface 112a of the substrate. In some embodiments, the force sensing device <NUM> may be an analog force sensing device. In some embodiments, the force sensing device <NUM> may be a digital force sensing device. In some embodiments, the force sensing device <NUM> may comprise at least one of a piezoresistive force sensing device and a microelectromechanical systems (MEMS) force sensing device. In some embodiments, the force sensing die included in the force sensing device <NUM> may be a small force sensing die that incorporates DRIE processing to minimize the overall size of the force sensing assembly and thereby minimize the overall size of the example disposable blood pressure monitoring device <NUM>.

In some embodiments, the housing <NUM> may be configured to enclose the force sensing device <NUM>. For example, the housing <NUM> may define an aperture <NUM> configured to provide a coupling interface configured to provide a path for the force to be transferred to the force sensing device <NUM> through a coupling. In some embodiments, the center of the aperture <NUM> may be configured to align with a center of the force sensing device <NUM>. In some embodiments, the coupling may be a gel-based coupling comprising a gel configured to transmit the force to the force sensing device. For example, the gel may be a biocompatible RTV material such as silicone. In some embodiments, the force sensing device <NUM> may be assembled into the housing <NUM> without a glue joint by, for example, assembling a radial seal ring structure in the housing <NUM> to engage the outer diameter of the gel ring on the force sensing device <NUM> to seal the force sensing device <NUM> into the housing <NUM>.

In some embodiments, a plurality of electrical contact pads (e.g., four electrical contact pads) may be disposed on the second surface 112b of the substrate. In some embodiments, the example disposable blood pressure monitoring device <NUM> may further comprise electrical cables <NUM> (e.g., four electrical cables), an electrical cable harness <NUM>, and an electrical connection terminal <NUM> (e.g., a six-pin plug). For example, the plurality of electrical contact pads may be, or may be attached to, a plurality of wedge terminals (e.g., four wedge terminals) configured to mechanically couple the plurality of electrical cables <NUM> to the plurality of electrical contact pads.

In some embodiments, as shown in <FIG>, the example disposable blood pressure monitoring device <NUM> may comprise a cable trap comprising one or more cable trap support structures configured to hold the electrical cables <NUM> against the substrate <NUM>. For example, the base plate <NUM> may comprise a cable trap support structure <NUM> configured to engage the one or more electrical cables <NUM>. In some instances, the cable trap support structure <NUM> on the base plate <NUM> may pinch the one or more electrical cables <NUM> against the one or more electrical contact pads disposed on the second surface 112b of the substrate <NUM> or the one or more wedge terminals attached thereto. In some instances, the cable trap support structure <NUM> on the base plate <NUM> may define a semi-circular notch for each of the one or more electrical cables <NUM>. For example, the semi-circular notch may have a diameter substantially similar to the diameter of each of the one or more electrical cables <NUM>. As a result, as shown in <FIG>, the lower half of each of the one or more electrical cables <NUM> may be cradled within each of the one or more semi-circular notches of the cable trap support structure <NUM> and only the upper half of each of the one or more electrical cables <NUM> may protrude above the cable trap support structure <NUM>. In some embodiments, the housing <NUM> may comprise a cable trap support structure <NUM> configured to restrict upward movement of the one or more electrical cables <NUM> and to restrict lateral movement of the substrate <NUM>.

In some embodiments, the base plate <NUM> is attached to the housing <NUM> using one or more snap structures. For example, housing <NUM> may comprise a downward-facing protrusion <NUM> configured to attach to an upward-facing protrusion <NUM> of the base plate <NUM>. In some instances, as shown in <FIG>, <FIG>, <FIG>, and <FIG>, the outward-facing surface of the downward-facing protrusion <NUM> of the housing <NUM> may be configured to be attached to the inward-facing surface of the upward-facing protrusion <NUM> of the base plate <NUM>. In other instances, the inward-facing surface of the downward-facing protrusion <NUM> of the housing <NUM> may be configured to be attached to the outward-facing surface of the upward-facing protrusion <NUM> of the base plate <NUM>.

In some embodiments, the downward-facing protrusion <NUM> of the housing <NUM> may be configured to be attached to the upward-facing protrusion <NUM> of the base plate <NUM> using an adhesive, such as a two-part epoxy resin. In some embodiments, the downward-facing protrusion <NUM> of the housing <NUM> is configured to be attached to the upward-facing protrusion <NUM> of the base plate <NUM> using one or more snap structures. In some embodiments, the bottom of the outward-facing surface of the downward-facing protrusion <NUM> of the housing <NUM> may have an outward-facing protrusion, and the bottom of the inward-facing surface of the upward-facing protrusion <NUM> of the base plate <NUM> may have a notch or groove configured to receive the outward-facing protrusion of the downward-facing protrusion <NUM> of the housing <NUM>. As the outward-facing surface of the downward-facing protrusion <NUM> of the housing <NUM> is being inserted against the inward-facing surface of the upward-facing protrusion <NUM> of the base plate <NUM>, the downward-facing protrusion <NUM> may be inwardly biased by the outward-facing protrusion of the downward-facing protrusion <NUM> contacting the inward-facing surface of the upward-facing protrusion <NUM> of the base plate <NUM>. Once the outward-facing protrusion of the downward-facing protrusion <NUM> has been inserted into the notch or groove of the inward-facing surface of the upward-facing protrusion <NUM>, the downward-facing protrusion <NUM> may snap outwardly to its original unbiased position, thereby locking the housing <NUM> into the base plate <NUM>.

In some embodiments, the optional signal conditioning circuitry may be configured to be electrically coupled to the force sensing device <NUM> and the plurality of electrical contact pads, and the housing <NUM> may be further configured to enclose the optional signal conditioning circuitry. In some embodiments, as shown in <FIG>, <FIG>, <FIG>, and <FIG>, where the force sensing device <NUM> is a digital force sensing device, a bottom surface of the optional signal conditioning circuitry may be configured to be disposed on the first surface 112a of the substrate <NUM>, and the force sensing device <NUM> may be configured to be disposed on a top surface of the optional signal conditioning circuitry (e.g., the optional signal conditioning circuitry may be disposed between the force sensing device <NUM> and the substrate <NUM>). In some embodiments, where the force sensing device <NUM> is either an analog force sensing device or a digital force sensing device, the optional signal conditioning circuitry may be configured to be disposed on the first surface 112a of the substrate separate from the force sensing device <NUM> (e.g., as arranged in <FIG>). In some embodiments, the optional signal conditioning circuitry may be configured to adjust the bridge output of the force sensing device <NUM> to correct for offset and span temperature effects.

In some embodiments, the example disposable blood pressure monitoring device <NUM> may comprise a digitally controlled resistor network <NUM>. For example, the digitally controlled resistor network <NUM> may comprise electrically erasable programmable read-only memory (EEPROM) circuitry configured to the particular requirements of the force sensing assembly, the example disposable blood pressure monitoring device <NUM>, or both. In some embodiments, the digitally controlled resistor network <NUM> may be an encryption memory storage to prevent counterfeit sensors from working with the example disposable blood pressure monitoring device <NUM>. In some embodiments, the digitally controlled resistor network <NUM> may be a digital encryption device. In some embodiments, the digitally controlled resistor network <NUM> may be an analog encryption device. In some embodiments, as shown in <FIG>, <FIG>, and <FIG>, the digitally controlled resistor network <NUM> may be disposed on the second surface 112b (e.g., the backside or terminal side) of the substrate <NUM>.

<FIG> shows an example cross-sectional view of an example disposable blood pressure monitoring device <NUM> in accordance with some example embodiments described herein. In some embodiments, as shown in <FIG>, the example disposable blood pressure monitoring device <NUM> may comprise a base plate <NUM> (e.g., a plastic base plate) attached to a housing <NUM> comprising a fluid monitoring tube, a luer lock <NUM>, and a luer lock fitting <NUM>. The housing <NUM> comprises one or more snap structures (e.g., snap structure <NUM>, snap structure <NUM>, or both) configured to attach the housing <NUM> to the base plate <NUM> and retain a force sensing device <NUM> and an optional signal conditioning circuitry <NUM> in the housing <NUM>.

The base plate <NUM> is attached to the housing <NUM> using one or more snap structures, such as a snap structure <NUM> and a snap structure <NUM>. The force sensing assembly is retained in the housing <NUM> by the snap structure <NUM> and the snap structure <NUM>. In some embodiments, the snap structure <NUM> and the snap structure <NUM> may be disposed between the base plate <NUM> and the housing <NUM> to retain the force sensing assembly in the housing <NUM> and sandwich the one or more electrical cables <NUM> against the one or more wedge terminals <NUM> that may be SMT mounted to the second surface 212b (e.g., backside) of the substrate <NUM>. The one or more wedge terminals <NUM> may act as springs to engage the one or more electrical cables <NUM> and create the electrical connection to external devices.

In some embodiments, the snap structure <NUM> may be a flexible arm (e.g., cantilever) connected to the housing <NUM> at the top end of the flexible arm and having an inward-facing protrusion <NUM> at the bottom end of the flexible arm. The base plate <NUM> may have an opening <NUM> configured to receive the snap structure <NUM>. As the snap structure <NUM> is being inserted into the opening <NUM> in the base plate <NUM>, the snap structure <NUM> may be outwardly biased by the inward-facing protrusion <NUM> contacting the inward-facing side of the opening <NUM>. Once the inward-facing protrusion <NUM> of the snap structure <NUM> has been inserted into the opening <NUM> in the base plate <NUM>, the snap structure <NUM> may snap inwardly to its original unbiased position, thereby locking the housing <NUM> into the base plate <NUM>.

In some embodiments, the housing <NUM> may be optically transparent or near-transparent to allow for visual confirmation (e.g., by an imaging device or a user's eye) that no bubbles are present in the fluid in the fluid monitoring tube or that air bubbles have been cleared therefrom. In some embodiments, the base plate <NUM> may not be optically transparent or near-transparent. For example, the housing <NUM> may be made of an optically transparent polymer or plastic while the base plate <NUM> may be made of a non-optically transparent polymer or plastic.

In some embodiments, the example disposable blood pressure monitoring device <NUM> may further comprise a force sensing assembly comprising a force sensing device <NUM> (e.g., comprising a force sensing die, a gel ring <NUM>, and a gel <NUM> (e.g., a biocompatible RTV material such as a silicone gel) having a gel surface <NUM>), wire bonds <NUM>, optional signal conditioning circuitry <NUM>, wire bonds <NUM>, and a substrate <NUM> (e.g., a PCB). The substrate <NUM> may comprise a first surface 212a (e.g., a top surface) and a second surface 212b (e.g., a bottom surface) opposite the first surface 212a.

In some embodiments, the gel <NUM> forms a gel surface <NUM> at the sharp top surface of the gel ring <NUM> so that the force from the external source may be concentrated through the gel <NUM> directly to the force sensing device <NUM>. In some embodiments, the gel surface <NUM> may be a domed or convex-shaped gel surface to avoid bubbles getting stuck in the fluid monitoring tube during fluid flow. For instance, in some embodiments a concave gel surface may create a low velocity zone in the fluid flow path and this low velocity zone could become a bubble trap. In some embodiments, a domed or convex-shaped gel surface may protrude slightly into the fluid flow path so as to allow for higher velocity zones in the fluid flow path and thereby decrease the occurrence of bubble traps without creating bubble traps at the edges.

In some embodiments, the gel <NUM> may be poured in the gel ring <NUM>. As the gel <NUM> reaches the sharp top surface of the gel ring <NUM>, the gel <NUM> stops and beads-up, resulting in the formation of the gel surface <NUM> (e.g., a domed or convex-shaped gel surface) of the gel <NUM> at the periphery of the aperture <NUM>. For example, surface tension effects, adhesion effects, or both may account for the formation of the gel surface <NUM> (e.g., a domed or convex-shaped gel surface) of the gel <NUM> at the periphery of the sharp top surface of the gel ring <NUM>. In some embodiments, the gel <NUM> may be a liquid gel. In other embodiments, the gel <NUM> may be a semi-liquid gel. In one example embodiment, the gel <NUM> may be a dielectric gel. In another example embodiment, the gel <NUM> may be a non-dielectric gel. In some embodiments, the gel <NUM> may be a silicone-based gel. It should be appreciated that, the gel <NUM> is only one example of the actuator, and it is contemplated that other suitable actuators may be used.

In some embodiments, the optional signal conditioning circuitry <NUM> may configured to be electrically coupled to the force sensing device <NUM> by one or more wire bonds. For example, the optional signal conditioning circuitry <NUM> may be configured to be electrically coupled to the substrate <NUM> by one or more wire bonds <NUM>, the force sensing device <NUM> may be configured to be electrically coupled to the substrate <NUM> by one or more wire bonds <NUM>, and the optional signal conditioning circuitry <NUM> may be configured to be electrically coupled to the force sensing device <NUM> through the substrate <NUM>. In other embodiments, the electrical connections may be solder bumps or use other electrical joining techniques, such as through silicon vias with solder bumps or thermosonic ball bump welds, which may provide a space improvement. In some embodiments, the optional signal conditioning circuitry <NUM> may be configured to adjust the bridge output of the force sensing device <NUM> to correct for offset and span temperature effects.

The force sensing device <NUM> is configured to be disposed on the first surface 212a of the substrate. In some embodiments, the force sensing device <NUM> may be an analog force sensing device. In some embodiments, the force sensing device <NUM> may be a digital force sensing device. In some embodiments, the force sensing device <NUM> may comprise at least one of a piezoresistive force sensing device and a MEMS force sensing device. In some embodiments, the force sensing die included in the force sensing device <NUM> may be a small force sensing die that incorporates DRIE processing to minimize the overall size of the force sensing assembly and thereby minimize the overall size of the example disposable blood pressure monitoring device <NUM>.

In some embodiments, the housing <NUM> may be configured to enclose the force sensing device <NUM>. For example, the housing <NUM> may define an aperture <NUM> configured to provide a coupling interface configured to provide a path for the force (e.g., the force applied by an external source (e.g., blood) in the fluid monitoring tube of the housing <NUM>) to be transferred to the force sensing device <NUM> through a coupling (e.g., gel <NUM> disposed in gel ring <NUM> and having a gel surface <NUM>). In some embodiments, the aperture <NUM> defined in the housing <NUM> may have, for example, a circular, elliptical, oval, or polygonal cross-section. In some embodiments, the aperture <NUM> may have a cross-sectional radius, such as, but not limited to, <NUM>, <NUM>, <NUM>, or any other suitable radius. In some embodiments, the center of the aperture <NUM> may be configured to align with a center of the force sensing device <NUM>. In some embodiments, the coupling may be a gel-based coupling comprising a gel <NUM> comprising a gel surface <NUM> and configured to transmit the force to the force sensing device <NUM>. For example, the gel <NUM> may be a biocompatible RTV material such as silicone. In other embodiments, the coupling may be a mechanical coupling such as a stainless steel ball, an aluminum ball, or any other suitable mechanical coupling. In some embodiments, the force sensing device <NUM> may be assembled into the housing <NUM> without a glue joint by, for example, assembling a radial seal ring structure (e.g., the aperture <NUM>) in the housing <NUM> to engage the outer diameter of the gel ring <NUM> on the force sensing device <NUM> to seal the force sensing device <NUM> into the housing <NUM>.

In some embodiments, a plurality of electrical contact pads (e.g., four electrical contact pads) may be disposed on the second surface 212b of the substrate. In some embodiments, the example disposable blood pressure monitoring device <NUM> may further comprise electrical cables <NUM> (e.g., four electrical cables), an electrical cable harness <NUM>, and an electrical connection terminal <NUM> (e.g., a six-pin plug). For example, the plurality of electrical contact pads may be, or may be attached to, a plurality of wedge terminals <NUM> (e.g., four wedge terminals) configured to mechanically couple the plurality of electrical cables <NUM> to the plurality of electrical contact pads.

In some embodiments, the example disposable blood pressure monitoring device <NUM> may comprise a digitally controlled resistor network. For example, the digitally controlled resistor network may comprise EEPROM circuitry configured to the particular requirements of the force sensing assembly.

In some embodiments, the optional signal conditioning circuitry <NUM> may be configured to be electrically coupled to the force sensing device <NUM> and the plurality of electrical contact pads, and the housing <NUM> may be further configured to enclose the optional signal conditioning circuitry <NUM>. In some embodiments, where the force sensing device <NUM> is either an analog force sensing device or a digital force sensing device, the optional signal conditioning circuitry <NUM> may be configured to be disposed on the first surface 212a of the substrate. In some embodiments, where the force sensing device <NUM> is a digital force sensing device, the optional signal conditioning circuitry <NUM> may be configured to be disposed on the first surface 212a of the substrate <NUM>, and the force sensing device <NUM> may be configured to be disposed on a top surface of the optional signal conditioning circuitry <NUM> (e.g., the optional signal conditioning circuitry <NUM> may be disposed beneath the force sensing device <NUM> or otherwise between the force sensing device <NUM> and the substrate <NUM>).

In some embodiments, the base plate <NUM> may comprise a push structure <NUM> to push on the substrate <NUM> to hold the gel ring <NUM> into the housing <NUM>. In some embodiments, the substrate <NUM> may further comprise one or more wedge terminals <NUM> that have been SMT mounted to the second surface 212b of the substrate <NUM>. In some embodiments, the base plate <NUM> may further comprise one or more cable wire guides configured to support (e.g., hold in place) the one or more electrical cables that engage the one or more wedge terminals <NUM>. The wedge terminals <NUM> (e.g., four wedge terminals) may be configured to act as springs to engage the electrical cables <NUM> (e.g., four electrical wires), which may also be pushed on and retained in place by the push structures <NUM> and the push structure <NUM>.

In some embodiments, the housing <NUM> may comprise a strain relief support structure <NUM> configured to engage the electrical cable harness <NUM>, which may also be engaged by an opposing strain relief support structure <NUM> on the base plate <NUM>. For example, the strain relief support structure <NUM> on the housing <NUM> and the opposing strain relief support structure <NUM> on the base plate <NUM> may pinch the electrical cable harness <NUM> to provide strain relief.

As shown in <FIG>, the force sensing assembly of the example disposable blood pressure monitoring device <NUM> may comprise the force sensing device <NUM>, the optional signal conditioning circuitry <NUM> (or, alternatively, the digitally controlled resistor network, or both), and a substrate <NUM>. In some embodiments (not shown in <FIG>), the optional signal conditioning circuitry <NUM> may be disposed within the gel <NUM> (e.g., near or beneath the force sensing device <NUM>). In other embodiments, as shown in <FIG>, the optional signal conditioning circuitry <NUM> may be disposed outside the gel <NUM> to provide the advantage of keeping the wire bonds <NUM> for the optional signal conditioning circuitry <NUM> out of the working path. In some instances, wire bonds disposed under the gel <NUM> may fatigue fail sooner than wire bonds that are not exposed to pressure or motion. By disposing the optional signal conditioning circuitry <NUM> outside of the gel <NUM>, this failure mode may be advantageously avoided. Additionally, disposing the optional signal conditioning circuitry <NUM> outside of the gel <NUM> provides for more flexible signal conditioning circuitry upgrade techniques to incorporate improvements in sensing or signal processing technologies.

In some embodiments, the force sensing device <NUM> may comprise a force sensing die, a gel ring <NUM>, and a gel <NUM> disposed on the first surface 212a (e.g., a top surface) of the substrate <NUM>. The gel ring <NUM> may be made of metal (e.g., aluminum, stainless steel) or plastic (e.g., liquid crystal polymer (LCP), polyphenylene sulfide (PPS), LCP/PPS, or any other suitable material) and affixed to the substrate <NUM> using an adhesive, such as a two-part epoxy resin. The gel ring <NUM> may be cylindrical in profile and may have <NUM> degree corners at the top surface of the gel ring <NUM> to provide a <NUM> degree seal between the gel surface <NUM> of the gel <NUM> and the top surface of the gel ring <NUM>. In some embodiments, the optional signal conditioning circuitry <NUM> (or, alternatively, the digitally controlled resistor network, or both) may be covered with a glob top over the wire bonds <NUM> to provide protection during handling and shipping.

In some embodiments, the force sensing device <NUM>, the gel ring <NUM>, the optional signal conditioning circuitry <NUM>, or a combination thereof may be mounted on the first surface 212a of the substrate <NUM> using an adhesive. In some embodiments, the adhesive may comprise one or more of silicone, RTV silicone, a silicone-epoxy, a soft epoxy, a regular or hard epoxy, or any combination thereof. In one example embodiment, the adhesive may comprise a conductive adhesive. In another example embodiment, the adhesive may comprise a non-conductive adhesive or any combination of the conductive and the non-conductive adhesive. It should be appreciated that, the adhesive is only one example of a suitable bonding mechanism, and it is contemplated that other bonding mechanisms (e.g., but not limited to, solder eutectic, etc.) may be used.

In some embodiments, the substrate <NUM> may comprise a PCB. In other embodiments, the substrate <NUM> may comprise any suitable material, such as, but not limited to, a dielectric material, an insulating material, or any combination thereof. In one example embodiment, the substrate <NUM> may be a polygon in planar shape, such as, but not limited to, square, rectangle, triangle, pentagon, or any other suitable shape. In another example embodiment, the substrate <NUM> may be a non-polygon in planar shape. In some embodiments, the substrate <NUM> may be about <NUM> millimeters (mm) x <NUM> in planar size. In other embodiments, the substrate <NUM> may have other suitable dimensions. In one example embodiment, the substrate <NUM> may be about <NUM> micrometers (microns) thick. In another example embodiment, the thickness of the substrate <NUM> may be about <NUM> microns, about <NUM> microns, about <NUM> microns, or any other suitable thickness.

In some embodiments, the electrical contact pads may correspond to metallic pads comprising one or more metals, for example, copper (Cu), silver (Ag), gold (Au), aluminum (Al), or a combination thereof. In one example embodiment, the electrical contact pads may be surface mounted on the second surface 212b of the substrate <NUM> using surface-mount technology (SMT). In another example embodiment, the electrical contact pads may be chemically disposed on the second surface 212b of the substrate <NUM> using a chemical process, such as, but not limited to, using a metal plating solution (such as copper plating solution) to deposit the metal on the second surface 212b of the substrate <NUM> to form the electrical contact pads. In yet another example embodiment, the electrical contact pads may be disposed through a process of etching on the second surface 212b of the substrate <NUM>. In other example embodiments, the electrical contact pads may be disposed on the first surface 212a of the substrate <NUM>.

In some embodiments, each of the electrical contact pads may be a polygon in planar shape, for example, triangle, rectangle, square, pentagon, hexagon, or any other suitable shape. In other embodiments, the electrical contact pads may be a non-polygon in planar shape. In some embodiments, each of the electrical contact pads may be about <NUM> x <NUM> in planar size. In other embodiments, each of the electrical contact pads may comprise any suitable planar size, such as, but not limited to <NUM> x <NUM>, <NUM> x <NUM>, <NUM> x <NUM>, <NUM> x <NUM>, <NUM> x <NUM>, or any other suitable planar size. In some embodiments, the electrical contact pads may be configured to provide an electrical connection with an external circuitry. The electrical contact pads may use a communication protocol to communicate with, and provide an electrical connection to, the external circuitry. For example, the communication protocol may include an Inter-Integrated Circuit (I2C) protocol, a Serial Peripheral Interface (SPI) protocol, or other communication protocols.

In some embodiments, the optional signal conditioning circuitry <NUM> is configured to even out variations in an input signal to make it suitable for further processing. The variations may arise due to factors such as, but not limited to, temperature variations, external noise, electromagnetic variations, other variations, or combinations thereof. In some embodiments, the optional signal conditioning circuitry <NUM> may comprise an application-specific integrated circuit (ASIC), an instrumentation amplifier, a microprocessor, a microcontroller, or a combination thereof. In some embodiments, the optional signal conditioning circuitry <NUM> may further comprise a digital amplifier with a built-in temperature sensor (not shown) for compensating temperature induced changes caused by the temperature variations.

In some embodiments, the optional signal conditioning circuitry <NUM> may be about <NUM> x <NUM> in planar size. In other embodiments, the optional signal conditioning circuitry <NUM> may comprise any suitable planar size, such as, but not limited to, <NUM> x <NUM>, <NUM> x <NUM>, <NUM> x <NUM>, or any other suitable planar size. In one example embodiment, the optional signal conditioning circuitry <NUM> may be about <NUM> thick. In another example embodiment, the thickness of the optional signal conditioning circuitry <NUM> may be about <NUM>, <NUM>, or any other suitable thickness.

In some embodiments, the optional signal conditioning circuitry <NUM> may be mounted on the first surface 212a of the substrate <NUM> using an adhesive. The optional signal conditioning circuitry <NUM> may be electrically coupled to the force sensing device <NUM> via one or more wire bonds such as wire bonds <NUM> and wire bonds <NUM>. The wire bonds <NUM> and the wire bonds <NUM> may comprise one or more metals, for example, aluminum (Al), copper (Cu), gold (Au), silver (Ag), or a combination thereof. The wire bonds <NUM> and the wire bonds <NUM> may be wire bonded through suitable wire bonding techniques, for example, thermosonic bonding, ultrasonic bonding, thermocompression bonding, or a combination of such techniques. In some embodiments, each of the wire bonds <NUM> and the wire bonds <NUM> may have a thickness of about <NUM> microns. In other embodiments, each of the wire bonds <NUM> and the wire bonds <NUM> may have any other suitable thickness. It should be appreciated that, wire bonds are only one example of establishing an electrical connection between the force sensing device <NUM> and the optional signal conditioning circuitry <NUM>, and it is contemplated that the optional signal conditioning circuitry <NUM> may be electrically connected to the force sensing device <NUM> via other ways such as, but not limited to, trace conductors, conductive elastomer pre-forms, conductive adhesives, anisotropic conductive adhesives, any other suitable connection, or a combination thereof.

In some embodiments, the optional signal conditioning circuitry <NUM> is electrically connected to the force sensing device <NUM>. In operation, the optional signal conditioning circuitry <NUM> is configured to receive the output signal of the force sensing device <NUM>, the optional signal conditioning circuitry <NUM> performs conditioning on the received output signal and further, provides a conditioned output signal for further processing. In some embodiments, the optional signal conditioning circuitry <NUM> may be disposed on the first surface 212a of the substrate <NUM> separately from the force sensing device <NUM>. In other embodiments, the optional signal conditioning circuitry <NUM> may be disposed on the first surface 212a of the substrate <NUM> as a part of the force sensing device <NUM>. In some embodiments, the optional signal conditioning circuitry <NUM> may be disposed on top of the force sensing device <NUM> and another circuitry may be disposed underneath the force sensing device <NUM> to provide additional features on the serial bus or analog signal path.

<FIG> shows a functional block diagram <NUM> illustrating a method of operation of an example disposable blood pressure monitoring device (e.g., example disposable blood pressure monitoring device <NUM>, example disposable blood pressure monitoring device <NUM>) in accordance with some example embodiments described herein. The example disposable blood pressure monitoring device may be connected to an external circuitry (not shown) through the electrical contact pads. The force sensing device (e.g., force sensing device <NUM>, force sensing device <NUM>) and the optional signal conditioning circuitry (e.g., optional signal conditioning circuitry <NUM>) may be connected via wire bonds and a substrate (e.g., substrate <NUM>, <NUM>). In operation, an external power source may supply a power voltage to the force sensing device via the electrical contact pads. The actuator (e.g., gel <NUM>) may exert a force against the force sensing device in response to receiving the force from an external source. The actuator may transfer the force to the force sensing device causing deflection in an electrical resistance of the force sensing device. The deflection in the electrical resistance may cause a change in an output signal of the force sensing device. This change in the output signal is an indication or measurement of the force applied by the external source. The optional signal conditioning circuitry may receive the change in the output signal and condition the received output signal.

Having described specific components, structures, and features of example devices that may carry out some functionality of the system described herein, example embodiments of the present disclosure are described below in connection with <FIG>.

<FIG> shows a flowchart <NUM> illustrating example operations for providing an example disposable blood pressure monitoring device in accordance with some example embodiments described herein. As shown by operation <NUM>, the example flowchart <NUM> may begin by disposing a plurality of electrical contact pads on a second surface (e.g., second surface 112b, second surface 212b) of a substrate (e.g., substrate <NUM>, substrate <NUM>). The substrate may comprise a first surface (e.g., first surface 112a, first surface 212a) opposite the second surface. As shown by operation <NUM>, the example flowchart <NUM> may proceed to mounting a force sensing device (e.g., force sensing device <NUM>, force sensing device <NUM>) on the first surface of the substrate. As shown by operation <NUM>, the example flowchart <NUM> may proceed to mounting signal conditioning circuitry (e.g., optional signal conditioning circuitry <NUM>) on the first surface of the substrate. As shown by operation <NUM>, the example flowchart <NUM> may proceed to assembling a housing (e.g., housing <NUM>, housing <NUM>) enclosing at least the force sensing device and the signal conditioning circuitry. The housing may define an aperture (e.g., aperture <NUM>) for providing a coupling interface. As shown by operation <NUM>, the example flowchart <NUM> may proceed to providing a coupling (e.g., gel <NUM> disposed in gel ring <NUM>) in the coupling interface. The coupling interface may provide a path for the force to be transferred to the force sensing device through the coupling. Optionally (not shown in <FIG>), wherein the housing comprises a snap structure configured to retain the force sensing device and the signal conditioning circuitry in the housing, the example flowchart <NUM> may proceed to providing attaching the housing to a base plate using the snap structure.

In some embodiments, operations <NUM>, <NUM>, <NUM>, and <NUM> may not necessarily occur in the order depicted in <FIG>. In some embodiments, one or more of the operations depicted in <FIG> may occur substantially simultaneously. In some embodiments, one or more additional operations may be involved before, after, or between any of the operations shown in <FIG>.

As described above, <FIG> illustrates an example flowchart describing operations performed in accordance with example embodiments of the present disclosure. It will be understood that each block of the flowchart, and combinations of blocks in the flowchart, may be implemented by various means, such as devices comprising hardware, firmware, one or more processors, and/or circuitry associated with execution of software comprising one or more computer program instructions. For example, one or more of the procedures described above may be performed by material handling equipment (e.g., a robotic arm, servo motor, motion controllers, and the like) and computer program instructions residing on a non-transitory computer-readable storage memory. In this regard, the computer program instructions which embody the procedures described above may be stored by a memory of an apparatus employing an embodiment of the present disclosure and executed by a processor of the apparatus. As will be appreciated, any such computer program instructions may be loaded onto a computer or other programmable apparatus (e.g., hardware) to produce a machine, such that the resulting computer or other programmable apparatus provides for implementation of the functions specified in the flowchart blocks. When executed, the instructions stored in the computer-readable storage memory produce an article of manufacture configured to implement the various functions specified in flowchart blocks. Moreover, execution of a computer or other processing circuitry to perform various functions converts the computer or other processing circuitry into a particular machine configured to perform an example embodiment of the present disclosure.

Accordingly, the described flowchart blocks support combinations of means for performing the specified functions and combinations of operations for performing the specified functions. It will also be understood that one or more flowchart blocks, and combinations of flowchart blocks, can be implemented by special purpose hardware-based computer systems which perform the specified functions, or combinations of special purpose hardware that execute computer instructions. For example, in one or more example embodiments, the functions described herein may be implemented by special-purpose hardware or a combination of hardware programmed by firmware or other software. In implementations relying on firmware or other software, the functions may be performed as a result of execution of one or more instructions stored on one or more non-transitory computer-readable media and/or one or more non-transitory processor-readable media. These instructions may be embodied by one or more processor-executable software modules that reside on the one or more non-transitory computer-readable or processor-readable storage media. Non-transitory computer-readable or processor-readable storage media may in this regard comprise any storage media that may be accessed by a computer or a processor. By way of example but not limitation, such non-transitory computer-readable or processor-readable media may comprise RAM, ROM, EEPROM, FLASH memory, disk storage, magnetic storage devices, or the like. Disk storage, as used herein, comprises compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc™, or other storage devices that store data magnetically or optically with lasers. Combinations of the above types of media are also included within the scope of the terms non-transitory computer-readable and processor-readable media. Additionally, any combination of instructions stored on the one or more non-transitory processor-readable or computer-readable media may be referred to herein as a computer program product.

Words such as "thereafter," "then," "next," and similar words are not intended to limit the order of the steps; these words are simply used to guide the reader through the description of the methods. Further, any reference to claim elements in the singular, for example, using the articles "a," "an" or "the," is not to be construed as limiting the element to the singular and may, in some instances, be construed in the plural.

As described above and with reference to <FIG>, example embodiments of the present disclosure thus provide for an example disposable blood pressure monitoring device. Thus, the example disposable blood pressure monitoring device disclosed herein may easily and cost-effectively meet all of the performance requirements and also be sufficiently sensitive to detect a blood pressure.

While various embodiments in accordance with the principles disclosed herein have been shown and described above, modifications thereof may be made by one skilled in the art without departing from the teachings of the disclosure. The embodiments described herein are representative only and are not intended to be limiting. Many variations, combinations, and modifications are possible and are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims which follow. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present disclosure. Furthermore, any advantages and features described above may relate to specific embodiments, but shall not limit the application of such issued claims to processes and structures accomplishing any or all of the above advantages or having any or all of the above features.

Also, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other devices or components shown or discussed as coupled to, or in communication with, each other may be indirectly coupled through some intermediate device or component, whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the scope disclosed herein.

Claim 1:
A system for sensing a force applied by an external source in a fluid monitoring tube, the system comprising:
a substrate (<NUM>; <NUM>) comprising a first surface (112a; 212a) and a second surface (212b; 212b) opposite the first surface (112a; 212a);
a force sensing device (<NUM>; <NUM>) comprising a force sensing die and a gel ring (<NUM>), wherein the force sensing device (<NUM>; <NUM>) is configured to be disposed on the first surface (112a; 212a) of the substrate (<NUM>; <NUM>);
signal conditioning circuitry (<NUM>) configured to be electrically coupled to the force sensing device (<NUM>; <NUM>);
a housing (<NUM>; <NUM>) configured to enclose the force sensing device (<NUM>; <NUM>) and the signal conditioning circuitry (<NUM>); and
a base plate (<NUM>; <NUM>),
wherein the housing (<NUM>; <NUM>) comprises the fluid monitoring tube and a snap structure (<NUM>, <NUM>) configured to attach the housing (<NUM>; <NUM>) to the base plate (<NUM>; <NUM>) and retain the force sensing device (<NUM>; <NUM>) and the signal conditioning circuitry (<NUM>) in the housing (<NUM>; <NUM>), and
wherein the base plate (<NUM>; <NUM>) comprises a push structure (<NUM>) to push on the substrate (<NUM>; <NUM>) so as to hold the gel ring (<NUM>) of the force sensing device (<NUM>; <NUM>) into the housing (<NUM>; <NUM>), the gel ring (<NUM>) being fit into a mating hole of the fluid monitoring tube.