Device including a screen-printed flexible substrate

Abstract

An apparatus, system and method for providing a small form factor wearable electronic medical device, having a screen- printed flexible substrate. The embodiments include: a flexible polyethylene terephthalate substrate; a plurality of conductive inks screen printed in a plurality of layers, one atop the other upon a base on of the layers, on each side of the substrate; a plurality of dielectric inks printed in layers between aspects of the plurality of layers of the conductive inks; a plurality of vias comprised of conductive inks printed through holes in the substrate; a plurality of contact pads comprised of conductive inks on each of the opposing faces suitable to receive therein pins of at least one hard electronic component, at least one of the hard electronic components comprising a sensor to provide a function of the medical device; a printed flexible conductive adhesive printed at locations of the pins; and a Bluetooth connectivity circuit associated with the substrate.

Description

DEVICE INCLUDING A SCREEN-PRINTED FLEXIBLE SUBSTRATECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. provisional application No. 63 / 661178, filed on June 18, 2024, incorporated herein by reference in its entirety.FIELD OF THE INVENTION

[0002] The disclosure relates generally to printed electronics, and, more particularly, to an apparatus, system, and method of providing a device including a screen-printed flexible substrate.BACKGROUND

[0003] Flexible hybrid electronics enable the printing of electronic features onto flexible substrates for use in a variety of contexts in which electronics packages were heretofore unknown, or were large, inflexible printed circuit boards (PCBs). Such contexts include, for example, the medical field and, more particularly, medical monitoring devices.

[0004] Medical monitors are thus generally either invasive, bulky, or both. This is the case because the medical monitor includes therein a microprocessor and a full-size PCB to carry out the electronic functionality of the device. Thus, the sheer physical size of the devices make them inconvenient and undesirable for use by the patient who needs to wear them. Needless to say, making a device that must be worn for medical purposes difficult and inconvenient to wear created a significant public health risk.

[0005] On the contrary, a flexible hybrid electronic medical monitoring device may provide a flexible and easily wearable device. However, to date printed electronics, particularly on a flexible substrate, lack the capability and refinement to provide the circuit complexity, density and functionality necessary for use in a compact, easily- wearable medical device.

[0006] Accordingly, the need exists for a small form factor electronic device, such as may be the size of a credit card or smaller, which is readily wearable for a variety of uses, and particularly for medical use.SUMMAR Y OF THE DISCLOSURE

[0007] The embodiments provide an apparatus, system and method for providing a device, such as a small form factor wearable electronic medical device, having a screen-printed flexible substrate. The embodiments include: a flexible polyethylene terephthalate substrate; a plurality of conductive inks screen printed in a plurality of layers, one atop the other upon a base on of the layers, on each side of the substrate; a plurality of dielectric inks printed in layers between aspects of the plurality of layers of the conductive inks; a plurality of vias comprised of conductive inks printed through holes in the substrate so as to connect the plurality of layers of conductive inks on an opposing face of the substrate; a plurality of contact pads comprised of conductive inks on each of the opposing faces suitable to receive therein pins of at least one hard electronic component, at least one of the hard electronic components comprising a sensor to provide a function of the medical device; a printed flexible conductive adhesive printed at locations of the pins so as to improve conductivity between the plurality of layers of conductive inks and the at least one hard electronic component; and a Bluetooth connectivity circuit associated with the substrate.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] This disclosure is illustrated by way of example and not by way of limitation in the accompanying figure(s). The figure(s) may, alone or in combination, illustrate one or more embodiments of the disclosure. Elements illustrated in the figure(s) are not necessarily drawn to scale. Reference labels may be repeated among the figures to indicate corresponding or analogous elements.

[0009] FIG. 1 illustrates aspects of an exemplary embodiment of the present invention;

[0010] FIG. 2 illustrates aspects of an exemplary embodiment of the present invention;

[0011] FIG. 3 illustrates aspects of the embodiments;

[0012] FIG. 4 illustrates aspects of the embodiments;

[0013] FIG. 5 illustrates aspects of an exemplary embodiment of the present invention;

[0014] FIG. 6 illustrates aspects of an exemplary embodiment of the present invention;

[0015] FIG. 7 illustrates aspects of the embodiments;

[0016] FIG. 8 illustrates aspects of the embodiments; and

[0017] FIG. 9 illustrates aspects of the embodiments.DETAILED DESCRIPTION

[0018] The figures and descriptions provided herein may have been simplified to illustrate aspects that are relevant for a clear understanding of the herein described devices, systems, and methods, while eliminating, for the purpose of clarity, other aspects that may be found in typical similar devices, systems, and methods. Those of ordinary skill may recognize that other elements and / or operations may be desirable and / or necessary to implement the devices, systems, and methods described herein. But because such elements and operations are well known in the art, and because they do not facilitate a better understanding of the present disclosure, a discussion of such elements and operations may not be provided herein. However, the present disclosure is deemed to inherently include all such elements, variations, and modifications to the described aspects that would be known to those of ordinary skill in the art.

[0019] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. For example, as used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having," are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0020] When an element or layer is referred to as being "on", "engaged to", "connected to" or "coupled to" another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged to", "directly connected to" or "directly coupled to" another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elementsshould be interpreted in a like fashion (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0021] Although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. That is, terms such as "first," "second," and other numerical terms, when used herein, do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the exemplary embodiments.

[0022] The embodiments provide a small form factor electronic medical device, such as may be the size of a credit card or smaller. The flexibility of the disclosed electronic device enables the device to be readily wearable for a variety of uses, such as for medical use. The disclosed flexible electronic substrate may also be provided with, for example, Bluetooth connectivity in order to enable data exchanges with the wearable device by external networked devices, such as cell phones.

[0023] By way of non-limiting example, ones of the embodiments provide multiple sensor types 10a, 10b, 10c associated with the wearable device. For example, without exceeding the complexity or density capabilities of the disclosed printed electronics, the flexible hybrid electronics substrate 12 may include thereon one or two temperature sensors, and / or one or two pressure sensors, such as on both sides 12a, 12b of substrate 12. In such an embodiment, an intravenous fluid feed 20 or other medicinal or health related fluid may pass through a feed line from, for example, an IV bag, across the sensor(s) through the device, and into a patient's arm. That is, in such a circumstance the fluid may be fed through the disclosed wearable electronic device so that both the temperature and pressure of the fluid may thereby be monitored as they pass through the device. This embodiment is more particularly illustrated in Figure 1.

[0024] The foregoing features may be provided based on a number of factors. For example, the conformability of the substrate and the disclosed electronics may allow for conformance of the medical device that includes said substrate directly to the skin. Further,sensors and circuitry 30 may be included on each face of the substrate within the device, thereby increasing the complexity, density and functionality of the provided electronic device without the need of expanding the substrate size on which the device is provided.

[0025] As mentioned, these capabilities may be provided by unique features available in the embodiments. For example, the flexible substrate may be a PET substrate. The printing that occurs on the substrate may be, for example, screen printing rather than other types of printing, although other types of printing may be used to provide the wiring 30 and "circuitry" in the embodiments. Further, electrically conductive adhesives may be used to ensure suitable connection of hard electrical components to the circuitry provided on the substrate. Moreover, suitable elastic electrical connections may be provided instead of, for example, soldering.

[0026] Yet further, the aforementioned double sided printing of the electronics, as illustrated in the substrate of Figure 2, may include ground plane features 80, as well as underside crossover vias 82, such as may use insulation layers 102 printed via alternate screen stencils between conductive layers, rather than over the top crossovers as are generally provided in the known art. Additionally included may be contact pads 30a as part of circuitry 30, and contact pads may include adhesive print points 30b. Finally, as mentioned previously, a printed Bluetooth antenna 40 may be provided. In some circumstances, the printed electronics and the flexible substrate may additionally include simple printed circuits, such as simple screen-printed sensors, to replace some hard components and thereby add to the flexibility while decreasing the size of the disclosed electronic device that contains the substrate.

[0027] The foregoing features, such as including the hard component electronics, printed electronics and printed sensors, and the Bluetooth communications, may be operated, in part, using onboard firmware that is stored on and run from the disclosed electronic device. The firmware may operate from, for example, a microcontroller / microprocessor.

[0028] More particularly, although several different methodologies of printing functional inks onto the flexible substrate may be used in the embodiments, screen printing may be the preferred methodology, as mentioned throughout. Screen printing allows for the use of different stencils for different types of inks, such that circuit features may be built one atop the other. For example, multiple silver ink layers may be provided in the embodiments, such as to provide crossover features, through the use of screen printing through different stencils. Further, dielectric layers may be printed via the use of yet a different stencil, such as to provide insulationbetween the multiple silver ink conductive layers.

[0029] In a typical embodiment, silver ink may be printed, for example, using a first conductive stencil. The printed ink may then be cured, such as to drive the solvents from the print. Thereby, the silver ink may be used to create a wire / wires and / or one or more contact pads, for example. Such a printing methodology allows for high levels of repeatability across multiple prints. As will be appreciated by the skilled artisan, different print times and temperatures may be used, particularly when different inks are printed, in order to get the proper conductivity / resistivity / insulative properties necessary to make the printed electronic circuit operable for the desired functionality.

[0030] Additionally, electrically conductive adhesive may also be used, such as at connection points on a connection pad, or underneath a pin connection for a hard electrical component on a face of the substrate opposing the connection side of the substrate, for example, in order to provide connectivity of the hard elements into the circuit that has been printed on the flexible substrate. These hard components may be, for example, placed into the design locations through a pick and place methodology, such as may employ a robotic pick and place machine.

[0031] Thus, bulk elements and sensors may be printed, rather than placed via pick and place as in the known art. The printing of these certain electronic elements, such as bulk electronic elements and / or simple sensors, such as temperature sensors, limits the size, expense, and processing overhead necessitated by and for hard elements that must be put on the board, such as through pick and place methodologies.

[0032] After all stencils, and thus all layers, are printed on the flexible substrate 12, and following placement of the hard electronic elements 10, some or all aspects of the printed electronic may then be encapsulated 102, such as by protective insulator 102, as illustrated in Figure 3. As will be discussed further herein, encapsulation may be varied, such as to further support flexibility of the resulting electronic device.

[0033] As referenced, particularly flexible areas (i.e., "flex areas") 106 may be provided in the layout of the printed electronics on a given flexible PET substrate. These may comprise vertical and / or horizontal regions that are void of parts, printed features, and particularly encapsulant. The PET substrate is flexible but not so flexible so as to be fully conformable, so providing the aforementioned flex areas aids in maximizing the flexibility of the provided circuitry for use in high conformability embodiments, particularly in embodiments wherein the hardelectronics are of a high density.

[0034] Accordingly, flex areas may be provided throughout the design, such as in a spacing clearance 110 of, for example, between 1 and 5, or particularly 2.5, millimeters. In these areas, no components or electronics are provided to allow for maximum flexibility. Further, encapsulation may not only be lacking in the flex areas but may be assigned a particular spacing across or adjacent to the flex areas. For example, each electronic feature on the substrate may be subjected to 500 micrometers of spacing clearance for the encapsulation of that element from the flex area. This is illustrated in Figure 3.

[0035] Also present is the use of crossovers and vias in the embodiments. As illustrated, traces may be routed over each other in order to reach necessary connection points, and in such circumstances, multiple conductive inks may have to be crossed over each other in separate layers without shorting together. In the embodiments, the total layer count is significantly decreased by the use of vias to move conduction between both sides of the printed substrate, and the printing of dielectric layers on a distinct stencil between at least two conductive layers which also each have distinct screen print stencils, such that crossovers may be produced with a dielectric between the layers to avoid undesired shorts.

[0036] As discussed, multiple stencils and multiple ink types to print the multiple ink layers may be employed to create each electronic device substrate. That is, different layers of the circuit on the substrate may be subjected to different stencils / screens for the screen print in order to obtain the desired pattern of the particular ink for each particular layer. Thereby, efficiency may dictate that multiple such substrates / boards 12 be created simultaneously at each stencil layer. Thus, a sheet of, for example, PET substrate may receive thereon multiple circuit boards on a single panel. By way of non-limiting example, six boards / substrates as disclosed may be provided on each panel of the PET substrate roll. Such as panel 202 is illustrated in Figure 4.

[0037] Design considerations for the embodiments include pad spacing, vias location, and suitable mechanical and electrical tolerances. Also of concern are conductive ink spacing, dielectric ink spacing, and the placement of flex areas in which neither inks, encapsulant, nor components may be present. Relatedly, encapsulant spacing must be so as to effectuate protection of the devices and circuitry, but so as not to adversely affect the flexibility particularly in the flex areas.

[0038] Also of consideration in the embodiments is the reduction in the total number ofdielectric and conductive print layers. This reduction is, in part, enabled by the elimination of a significant number of crossovers, which are replaced by the use of vias between substrate sides, and the optimized and detailed stencil printing of each overlapping layer. Needless to say, the reduced total number of layers provided in the embodiments also allows for a reduction in the number of screen stencils used in the printing process.

[0039] A variety of inks may be used in the embodiments, and it should be noted that different inks may be used for different purposes. That is, different conductive screen stencil layers may be printed using different conductive inks, and the same may be true of dielectric or insulative layers. Nevertheless, in some embodiments and by way of example only, silver ink CXT0644 and dielectric ink DESU4605G may be employed.

[0040] Also of note and as referenced throughout, the time and temperature of ink curing may vary, and it will thus be appreciated by the skilled artisan that the curing method of one ink layer must not affect the performance of another ink layer. A further consideration includes inks for which multiple curing steps are performed, as a deleterious effect on a separate ink layer may not occur during a first cure of a certain ink, and it also must be ensured that a twice cured ink does not have its second cure adversely affect the performance of other inks in the design.

[0041] It should also be noted that the viscosity of the inks during printing may result in different electrical performance. For example, resistance may vary once an ink is cured, such as dependent upon its viscosity when it was mixed or printed.

[0042] Further, the print order of the layers may affect a variability in the quality of the device produced. For example, for certain screen stencils, a bottom-side initial print on the substrate may produce better quality for a certain design than an initial print on the top-side of the substrate.

[0043] As discussed, encapsulation is provided to provide protection to the components and printed features, as well as to prevent shorts or undesirable crosstalk. However, encapsulation cannot simply be globally provided, in part because certain features may not work if subjected to encapsulation. By way of example, if a switch is encapsulated, it is likely that the switch will no longer be operable. Therefore, encapsulation should be avoided on some, and particularly on mechanical, features. Nevertheless, it may be necessary to provide some protective cover for those mechanical features, as will be apparent to those skilled in the art, and thus alternative protection methods may be applied to such features.

[0044] As discussed, various stencils may be provided for printing inks upon each face of the substrate, or a top each substrate and a panel of substrates. Accordingly, vacuum may be provided, either on the substrate or on a template corresponded with a screen stencil, for example, to hold each stencil and / or the substrate in a precise location to allow for precision in printing of each layer with respect to each other layer, i.e., to enable precision of the location of each stencil with respect to each other stencil. Considerations for this vacuum include avoiding bowing of the substrate, deformation of the screen stencils, or variability or deformation in printing, component placement, or the like.

[0045] As discussed throughout, component placement may occur via a pick and place machine, such as a Fuji pick and place machine, onto pad locations having conductive paste, such as printed conductive paste, located at the site of the component attachment on printed contact pads. Alternatively or additionally, adhesive glue may be dispensed, such as by printing, underneath component placement locations, i.e., on the opposing face of the substrate, in order to aid in attachment of components to the substrate.

[0046] As illustrated in the flow diagram of Figure 5, a vacuum template may be applied to a substrate and / or to a screen stencil 502. The assembly line may then follow a program 504 and apply the applicable screen prints 506. The screen prints may employ different stencils as discussed throughout and may include both dielectrics / insulators and conductors.

[0047] Following the electronic feature printing 510, which may additionally include the printing of simple bulk components and sensors as discussed above, a glue print 512 may occur at the sites of component attachment. Thereafter, components may be placed by 520, for example, a pick and place machine. Thereafter, one or more curing steps may be performed.

[0048] After curing 522, debug and testing 530 may occur. Following confirmation that the board is functional for its intended purpose, encapsulation 540 may occur, such as including optimization of flexibility 542 for substrates for certain uses, and contemplation of component functions, such as for mechanical components which cannot have encapsulation applied thereto. Finally, individual substrates may be removed from a panel of substrates 550 as needed and may be incorporated into devices.

[0049] As discussed, Bluetooth communication may be incorporated on-board the substrate, such that the device into which the substrate is placed is capable of Bluetooth communication with, for example, a nearby device. The data accrued by a functional circuit onthe substrate may thereby be passed to the nearby device, such as a mobile device, for manipulation or presentation on one or more applications or apps.

[0050] As such, Figures 6, 7, 8 and 9 illustrate such an app for a medical device capable of sensing both temperature and pressure, such as for the delivery of intravenous fluids. In Figure 6, a main screen is presented to a user on which the user may select the function the user wishes to access on the device with which the mobile is communicating. Figures 7 and 8 illustrate app screens presented to a user responsive to the user's request for information from the sensors on the substrate within the correspondent device. Figure 9 illustrates the current data from multiple sensors within the correspondent device.

[0051] In the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of clarity and brevity of the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the embodiments require more features than are expressly recited herein. Rather, the disclosure is to encompass all variations and modifications to the disclosed embodiments that would be understood to the skilled artisan in light of the disclosure.

Claims

CLAIMSWhat is claimed is:

1. A small form factor wearable electronic medical device, comprising: a flexible polyethylene terephthalate substrate; a plurality of conductive inks screen printed in a plurality of layers, one atop the other upon a base one of the layers, on each side of the substrate; a plurality of dielectric inks printed in layers between aspects of the plurality of layers of the conductive inks; a plurality of vias comprised of conductive inks printed through holes in the substrate so as to connect the plurality of layers of conductive inks on an opposing face of the substrate; a plurality of contact pads comprised of conductive inks on each of the opposing faces suitable to receive therein pins of at least one hard electronic component, at least one of the hard electronic components comprising a sensor to provide a function of the medical device; a printed flexible conductive adhesive printed at locations of the pins so as to improve conductivity between tile plurality of layers of conductive inks and the at least one hard electronic component; and a Bluetooth connectivity circuit associated with the substrate.

2. The device of claim 1, wherein the Bluetooth connectivity circuit serves to exchange data with external networked devices.

3. The device of claim 2, wherein the external networked device is a cell phone.

4. The device of claim 1, wherein the at least one sensor is a temperature sensor.

5. The device of claim 1, wherein the at least one sensor is a pressure sensor.

6. The device of claim 1, wherein the at least one sensor senses an intravenous fluid feed.

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