Flexible printed circuit board having battery mounted thereto

Abstract

To solve such a problem that a need exists to provide battery power to small battery-operated electronic devices having a flexible PCB without adversely affecting the flexibility of the flexible PCB.SOLUTION: A flexible printed circuit board (PCB) may have one or more coin type batteries mounted thereto such that the flexibility of the flexible PCB is maintained. The flexible PCB has one or more battery contact pads fabricated thereon. Each battery contact pad includes a pattern of metalized vias each extending from a top surface to a bottom surface of the flexible PCB. The coin type battery may be positioned over or under the battery contact pad. Conductive photocurable epoxy is applied to and in each metalized via to contact and adhere to the coin type battery to form a conductive path from the battery through the battery contact pad to printed conductors on the flexible PCB.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This claims priority to U.S. Provisional Patent Application No. 62 / 989,587, filed March 13, 2020, the disclosure of which is incorporated herein by reference in its entirety for all purposes.

[0002] The present invention relates generally to battery-powered devices, and more particularly to battery-powered devices that include a flexible printed circuit board (PCB). [Background technology]

[0003] A flexible PCB is an assembly of electronic circuits and components fabricated on a flexible substrate. Compared to rigid PCBs, flexible PCBs have numerous advantages, including the ability to conform to a desired shape (e.g., bend). Many small, battery-powered electronic devices could benefit from having a flexible PCB. However, the battery or batteries and battery holders in such devices are typically the thickest part of the electronic assembly on the PCB, thus adding rigidity to the PCB and defeating the purpose of having a flexible PCB. Therefore, there is a need for a way to provide battery power to small, battery-powered electronic devices with flexible PCBs without adversely affecting the flexibility of the flexible PCB. Summary of the Invention

[0004] According to one aspect, there is provided a flexible printed circuit board (PCB) comprising: a metallized via extending through the flexible PCB from a first surface to an opposite second surface of the flexible PCB; a battery in contact with the first surface and covering the metallized via; and a conductive light-curable epoxy disposed on the second surface over and in the metallized via such that the conductive light-curable epoxy contacts and adheres to the battery and provides a conductive path from the battery to the metallized via.

[0005] According to another aspect, a flexible PCB is provided, comprising first and second portions, the first portion separated from the second portion by a slit extending through the flexible PCB from the top surface to the bottom surface. The flexible PCB also comprises first and second metallized vias, the first metallized via extending through the flexible PCB from the top surface to the bottom surface of the first portion, and the second metallized via extending through the flexible PCB from the top surface to the bottom surface of the second portion. The flexible PCB further comprises a battery inserted into the slit such that the battery contacts the bottom surface of the first portion below the first metallized via and contacts the top surface of the second portion above the second metallized via. The flexible PCB further comprises a first conductive photocurable epoxy and a second conductive photocurable epoxy. The first conductive photocurable epoxy is disposed over and within the first metallized via on the top surface of the first portion such that the first conductive photocurable epoxy contacts and adheres to the battery, providing a conductive path from the battery to the first metallized via. and a second conductive light-curable epoxy is disposed over and within the second metallized via on the bottom surface of the second portion such that the second conductive light-curable epoxy contacts and adheres to the battery and provides a conductive path from the battery to the second metallized via.

[0006] According to another aspect, there is provided a flexible PCB comprising: a first metallized via extending through the flexible PCB from a top surface to a bottom surface of the flexible PCB; a battery disposed on the top surface over the first metallized via; a first conductive light-curable epoxy disposed on and within the first metallized via on the bottom surface of the flexible PCB such that the first conductive light-curable epoxy contacts and adheres to the battery and provides a conductive path from the battery to the first metallized via; an arm comprising a second metallized via extending through the arm from its top surface to its bottom surface, the arm being disposed on the battery such that a bottom surface of the arm contacts the battery and the second metallized via is above the battery; and a second conductive light-curable epoxy disposed on and within the second metallized via on the top surface of the arm such that the second conductive light-curable epoxy contacts and adheres to the battery and provides a conductive path from the battery to the second metallized via.

[0007] Further aspects, features, and advantages of the present disclosure will be readily apparent from the following detailed description and drawings of several exemplary embodiments and examples, including the best mode contemplated for carrying out the invention. The present disclosure is also capable of other and different embodiments, and its several details may be modified in various respects without departing from the scope of the present invention. The present disclosure is intended to cover all modifications, equivalents, and alternatives that fall within the scope of the appended claims (see further below). [Brief explanation of the drawings]

[0008] The drawings described below are for illustrative purposes and are not necessarily drawn to scale. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive. The drawings are not intended to limit the scope of the invention in any way.

[0009] [Figure 1]FIG. 1A is a plan view of a portion of a flexible printed circuit board (PCB) with battery contact pads formed thereon, according to an embodiment.

[0010] FIG. 1B is a cross-sectional side view of a portion of the flexible PCB of FIG. 1A taken along section line 1B-1B of FIG. 1A.

[0011] [Figure 2] FIG. 2 is a cross-sectional side view of another portion of a flexible PCB to which a coin cell battery is attached and electrically connected, according to an embodiment.

[0012] [Figure 3] FIG. 3 is a flowchart of a method for attaching a coin cell battery to a flexible PCB, according to an embodiment.

[0013] [Figure 4] 4A and 4B are plan views of another portion of a flexible PCB with multiple slits or cuts positioned to accommodate the attachment and electrical connection of one or more batteries to the flexible PCB, according to an embodiment.

[0014] [Figure 5] FIG. 5 is a flowchart of another method for attaching a coin cell battery to a flexible PCB, according to an embodiment.

[0015] [Figure 6] FIG. 6A is a plan view of a flexible PCB with extending foldable arms, according to an embodiment.

[0016] 6B and 6C are plan and side views, respectively, of the flexible PCB of FIG. 6A with the foldable arms folded for attaching and electrically connecting a pair of coin cell batteries to the flexible PCB, according to an embodiment.

[0017] [Figure 7]FIG. 7 is a plan view of flexible PCB materials configured to produce flexible PCBs each with a foldable arm, according to an embodiment.

[0018] [Figure 8] FIG. 8 is a plan view of a flexible PCB with attachable arms for attaching and electrically connecting a pair of coin cell batteries to the flexible PCB, according to an embodiment.

[0019] [Figure 9] FIG. 9 is a top view of the attachable arm of FIG. 8, according to an embodiment.

[0020] [Figure 10] FIG. 10 is a flowchart of another method for attaching a coin cell battery to a flexible PCB, according to an embodiment.

[0021] [Figure 11] FIG. 11 is a plan view of a flexible PCB with battery contact pads, according to an embodiment.

[0022] [Figure 12] FIG. 12 is a simplified planar block diagram of a continuous glucose monitor (CGM) wireless transmitter with a flexible PCB according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] A flexible printed circuit board (PCB) can comprise, for example, an assembly of electronic circuits and / or components surface-mounted on a flexible plastic substrate. The flexible plastic substrate can be, for example, polyimide, polyetheretherketone (PEEK), conductive transparent polyester film, etc. Flexible PCBs are typically very thin, typically no more than a few millimeters thick. Flexible PCBs can advantageously fold or bend during use. In contrast, rigid PCBs, which are thicker than flexible PCBs, can break and / or the circuits imprinted thereon can malfunction if they are folded or bent during use.

[0024] A small, battery-powered electronic device that can benefit from a flexible PCB is a continuous glucose monitor (CGM) wireless transmitter. A CGM wireless transmitter can be placed on a user's body to automatically take periodic blood glucose measurements and wirelessly transmit those measurements to a receiver and / or insulin pump. A CGM wireless transmitter with a flexible PCB for the sensor and wireless transmitter circuitry allows the CGM wireless transmitter to conform to the surface of the user's body at the attachment site, thereby improving adhesion and / or user comfort while wearing the CGM wireless transmitter. CGMs are typically powered by coin-cell batteries, such as small silver oxide batteries. However, coin-cell batteries held in conventional coin-cell battery holders, which are typically configured to attach to rigid PCBs, defeat the purpose of having a flexible PCB because the thickness and size of the battery holder add rigidity to the flexible PCB.

[0025] According to embodiments disclosed herein, coin-cell batteries (and batteries of similar configuration) can be directly attached to a flexible PCB without the use of a conventional battery holder. Such direct attachment maintains the overall flexibility of the flexible PCB by minimizing the additional thickness added to the flexible PCB by the coin-cell batteries. For example, in one embodiment, a flexible PCB with one or more coin-cell batteries directly attached thereto may have a maximum thickness of only about 1.6 mm, thus allowing a CGM wireless transmitter with a flexible PCB to easily conform to the surface of a user's body at the attachment site.

[0026] To ensure a reliable mechanical and electrical connection between the battery and the flexible PCB, battery contact pads formed on the flexible PCB and methods for connecting a battery to the flexible PCB according to one or more embodiments are provided, as described in more detail below in connection with FIGS. 1A-12.

[0027] 1 and 1B illustrate a portion 100 of a flexible PCB 102 having battery contact pads 104 formed thereon, according to one or more embodiments. The battery contact pads 104 include a plurality of metallized vias 106 (only a few of which are labeled in FIG. 1A ) arranged in a pattern. Other suitable patterns than those shown may be used. Each metallized via 106 is a through-hole extending through the flexible PCB 102 from a first surface 108 to an opposite second surface 110 of the flexible PCB 102. For example, a conductive metal 111, such as copper, may be disposed on and entirely over the inner surface of each metallized via 106. Other suitable conductive metals may be used. Printed conductors 112a formed on the first surface 108 surround and electrically connect the plurality of metallized vias 106 to one another, and printed conductors 112b formed on the second surface 110 also surround and electrically connect the plurality of metallized vias 106 to one another. Thus, the plurality of metallized vias 106 electrically connect the printed conductors 112a and 112b to one another. The printed conductors 112a and 112b may be copper or any other electrical conductor suitable for printing on a flexible PCB. In some embodiments, each metallized via 106 may have a diameter ranging from 0.5 mm to 2 mm, and the battery contact pads 104 may have a diameter ranging from 3 mm to 15 mm.

[0028] FIG. 2 illustrates a portion 200 of a flexible PCB 202 including a battery 214 attached to a battery contact pad 204 on a bottom surface 210 of the flexible PCB 202, according to one or more embodiments. The battery contact pad 204 may be similar to or identical to the battery contact pad 104. The battery 214 may be a coin-cell battery, or more specifically, a small silver oxide battery. Alternatively, the battery 214 may be of another type having a similar outline (e.g., a flat surface). A conductive light-curable epoxy, such as a conductive UV-curable epoxy 216, is disposed on the top surface 208 over and within each metallized via 206 (only three are shown in FIG. 2 ), such that the conductive UV-curable epoxy 216 contacts and adheres to the battery 214, providing a conductive path from the battery 214 through the metallized via 206 to the printed conductor 212 a (and, in some embodiments, to the printed conductor 212 b on the bottom surface 210). The printed conductors 212a may connect to other circuits, components, or connectors (not shown) on the flexible PCB 202. The conductive UV-curable epoxy 216 may be, for example, Elecolit® 3063, 3064, or 3065 manufactured by Panacol-Elosol GmbH. Advantageously, the battery 214 is attached directly to the flexible PCB 202 without a battery holder.

[0029] 3 illustrates a method 300 for attaching a battery to a flexible PCB according to one or more embodiments. At process block 302, the method 300 may include placing battery contact pads of the flexible PCB on a surface of the battery. For example, as shown in FIG. 2, the battery contact pads 204 of the flexible PCB 202 may be placed on the top surface of a coin cell battery 214.

[0030] At process block 304, the method 300 can include applying conductive UV-curable epoxy to the battery contact pads such that the epoxy fills the metallized vias of the battery contact pads and contacts the surface of the battery. The conductive UV-curable epoxy is used as an adhesive and / or a "cold" solder for surface-mounting components to a flexible PCB, particularly heat-sensitive components. The conductive UV-curable epoxy can be applied by any suitable method and should at least substantially fill the metallized vias so that a sufficient amount of the epoxy contacts the surface of the battery to establish a reliable mechanical and electrical connection between the battery and the metallized via. Referring again to FIG. 2, the conductive UV-curable epoxy 216 preferably completely fills each of the metallized vias 206 and completely contacts the top surface of the battery 214.

[0031] At process block 306, the method 300 may include irradiating the battery contact pads with ultraviolet light to cure the conductive UV-curable epoxy. As shown in FIG. 2, the conductive UV-curable epoxy 216 covering the battery contact pads 204 is irradiated with ultraviolet light 218 to cure the conductive UV-curable epoxy 216, thus establishing a reliable mechanical and electrical connection between the battery 214 and the metallized via 206. Depending on the power of the UV light, the type of epoxy, and the ambient temperature, the cure time may range from a few seconds to as much as a minute. Upon curing, a robust conductive bond is formed between the battery and the battery contact pads.

[0032] In particular, the pattern of metallized vias on the battery contact pads advantageously accelerates the curing of the conductive UV-curable epoxy, ensuring that most or all of the epoxy is not left uncured, which can weaken or prevent the formation of reliable mechanical and electrical connections. The pattern of metallized vias increases the conductive area, which lowers the overall connection resistance, and the relatively large vias allow UV light to reach the bottom of the epoxy in each via (i.e., the cell surface), which improves curing.

[0033] 2 (only one terminal, e.g., the negative terminal, is shown connected), a second connection must be made to the other terminal (e.g., the positive terminal) on the bottom surface of the battery 214. Figures 4A, 4B, 6A-6C, and 8 illustrate several embodiments in which the second connection to the battery can be made while advantageously maintaining the overall flexibility of the flexible PCB.

[0034] 4A and 4B illustrate a portion 400 of a flexible PCB 402 including battery contact pads 404a-404d and multiple slits or cuts 420a, 420b, and 420c disposed in the flexible PCB 402 to accommodate attachment of one or more coin cells 414a and 414b (or similarly configured batteries) to the flexible PCB 402 at the battery contact pads 404a-404d, according to one or more embodiments. Each of the battery contact pads 404a-404d may be similar to or identical to the battery contact pad 104. Each of the slits 420a-420c extends through the flexible PCB 402 from the top surface 408 to the bottom surface (not shown in FIGS. 4A and 4B) of the flexible PCB 402. The slits 420a-420c may be fabricated in any suitable manner. Slits 420a and 420b form a first portion 422 that includes battery contact pads 404a and 404b, and slits 420b and 420c form a second portion 424 that includes battery contact pads 404c and 404d. First portion 422 is separated from second portion 424 by slit 420b.

[0035] 4B , battery 414a can be inserted into slit 420b and through slit 420a, with one surface of battery 414a (e.g., the negative terminal side as shown) contacting the bottom surface of first portion 422 below battery contact pad 404a (and its metalized via) and the opposite surface (e.g., the positive terminal side) contacting the top surface 408 of second portion 424 above battery contact pad 404c (and its metalized via). Similarly, battery 414b can be inserted into slit 420b and through slit 420a, with one surface of battery 414a (e.g., the positive terminal side as shown) contacting the bottom surface of first portion 422 below battery contact pad 404a (and its metalized via) and the opposite surface (e.g., the negative terminal side) contacting the top surface 408 of second portion 424 above battery contact pad 404c (and its metalized via).

[0036] For example, as also shown in FIG. 2 and described below in connection with FIG. 5, to form a mechanical linkage and electrical connection between the batteries 414a and 414b and the battery contact pads 404a-404d, a conductive UV-curable epoxy can be disposed on and within the plurality of metallized vias of each of the battery contact pads 404a-404d, such that after being cured by UV light, the conductive UV-curable epoxy contacts and adheres to each of the batteries 414a and 414b, providing a conductive path from each of the batteries 414a and 414b to its respective pair of battery contact pads 404a-404d (and the plurality of metallized vias).

[0037] In some embodiments, depending on the configuration of imprinted and / or attached circuitry and / or components (not shown) on flexible PCB 402, batteries 414a and 414b can instead be inserted under second portion 424 and contact battery contact pads 404a-404d in the opposite manner to that shown in FIG. 4B.

[0038] It should also be noted that printed conductors (not shown) may electrically connect the battery contact pads 404a-404d with other circuits and / or components imprinted on and / or attached to the flexible PCB 402.

[0039] Furthermore, although two batteries 414a and 414b are shown, it should be noted that in other embodiments, portion 400 and slits 420a-420c are configured to accommodate only a single coin cell battery, depending on the power needs of the circuitry and / or components to be imprinted and / or attached to flexible PCB 402.

[0040] 5 illustrates a method 500 for attaching a coin cell battery (or similarly configured battery) to a flexible PCB including multiple slits for accommodating the battery, according to one or more embodiments. At process block 502, the method 500 can include providing a flexible PCB including at least two battery contact pads and multiple slits positioned to accommodate at least one battery. For example, as shown in FIG. 4A, a flexible PCB 402 can include battery contact pads 404a-404d and multiple slits 420a, 420b, and 420c positioned to accommodate one or more coin cell batteries 414a and / or 414b.

[0041] At process block 504, method 500 may include inserting a battery into one or more slits such that the battery contacts one battery contact pad on one surface of the battery and the other battery contact pad on the opposite surface of the battery. For example, as shown in FIG. 4B, battery 414a may be inserted into and through slit 420b such that one surface of battery 414a (e.g., the negative terminal side as shown) contacts battery contact pad 404a (and its metallized via), and the opposite surface of battery 414a (e.g., the positive terminal side) contacts battery contact pad 404c (and its metallized via).

[0042] At process block 506, the method 500 may include applying a conductive UV-curable epoxy to an accessible side of each contact pad such that the epoxy fills the metallized vias of each contact pad and contacts the battery surface. For example, with reference to FIGS. 2, 4A, and 4B, a first conductive UV-curable epoxy (e.g., conductive UV-curable epoxy 216) may be applied onto and into the battery contact pad 404a (and its metallized vias) on the top surface 408 of the first portion 422 such that the first conductive UV-curable epoxy contacts the negative terminal side of the battery 414a. Additionally, a second conductive UV-curable epoxy (e.g., conductive UV-curable epoxy 216) may be applied onto and into the battery contact pad 404c (and its metallized vias) on the bottom surface (not shown in FIG. 4B) of the second portion 424 such that the second conductive UV-curable epoxy contacts the positive terminal side (not shown in FIG. 4B) of the battery 414a.

[0043] At process block 508, method 500 can include irradiating each battery contact pad with ultraviolet light to cure the conductive ultraviolet-curable epoxy. Referring to FIG. 4B and continuing with the above example, the first conductive ultraviolet-curable epoxy on and in battery contact pad 404a can be irradiated with ultraviolet light (e.g., ultraviolet light 218 in FIG. 2 ) to cure the first conductive ultraviolet-curable epoxy, thereby establishing a reliable mechanical connection between the negative terminal side of battery 414a and battery contact pad 404a (i.e., the cured epoxy adheres to the surface of the battery and the metallized via). A conductive path from the negative terminal side of battery 414a to and through battery contact pad 404a (via its metallized via) is also established. Similarly, the second conductive UV-curable epoxy on and in the battery contact pad 404c can be irradiated with UV light (e.g., UV light 218 in FIG. 2 ) to cure the second conductive UV-curable epoxy, thus establishing a reliable mechanical connection between the positive terminal surface of the battery 414a and the battery contact pad 404c. A conductive path is also established from the positive terminal surface of the battery 414a to and through the battery contact pad 404c (via its metallized via). Note that the first and second conductive UV-curable epoxies can be irradiated with UV light sequentially or simultaneously (e.g., by one UV illuminator directed toward the top surface 408 of the flexible PCB 402 and another UV illuminator directed toward the bottom surface (not shown) of the flexible PCB 402).

[0044] 6A-6C illustrate a flexible PCB configuration 600 including a foldable arm 626 configured to attach and electrically connect a pair of coin cell batteries 614a and 614b (or similarly configured batteries) to a flexible PCB 602, according to one or more embodiments. As shown in FIG. 6A, the flexible PCB 602 initially has a foldable arm 626 extending therefrom. The foldable arm 626 can include battery contact pads 604a and 604b formed therein, which can be connected to each other by printed conductors 612a on one surface of the foldable arm 626 and, in some embodiments, by printed conductors 612b on the opposite surface of the foldable arm 626 (see FIG. 6B). Each of the battery contact pads 604a and 604b can be similar to or identical to the battery contact pads 104. The flexible PCB 602 may include one or more coin cell batteries 614a and 614b disposed on a top surface 608 of the flexible PCB 602 over respective battery contact pads 604c and 604d (see FIG. 6C ) formed on the flexible PCB 602. Each of the battery contact pads 604c and 604d may be similar to or identical to the battery contact pad 104. In those embodiments where only a single battery is required, the foldable arm 626 and flexible PCB 602 may each include only one suitably positioned battery contact pad, and the length of the foldable arm 626 may be adjusted accordingly.

[0045] In embodiments where some rigidity is desired in the area where one or more batteries are attached to facilitate the assembly process of the flexible PCB 602, a non-conductive battery stiffener 628 may be used to hold the batteries 614a and 614b. The battery stiffener 628 may have a height or thickness that does not exceed the height or thickness of the batteries 614a and 614b. Any suitable non-conductive material (e.g., hard plastic) can be used to fabricate the battery stiffener 628. The battery stiffener 628 can advantageously provide rigidity to the battery attachment area without increasing the height of the battery, circuitry, and / or component PCB assembly. The flexibility of the remainder of the flexible PCB 602 is not adversely affected by the battery stiffener 628.

[0046] 6B and 6C illustrate a flexible PCB 602 with a foldable arm 626 that folds up over batteries 614a and 614b. In some embodiments, the foldable arm 626 may have a radius R of about 1.5 mm (+ / - 0.1 mm) at the fold. The foldable arm 626 is configured to fold up over only one surface of the flexible PCB 602 (e.g., onto the top surface 608 as shown). That is, the foldable arm 626 is pre-cut and manufactured to fold over either the top or bottom surface of the flexible PCB 602 (but not both). The folding arm 626 can be mechanically and electrically coupled to the batteries 614a and 614b (as shown in FIG. 6C ) by applying and curing a conductive UV-curable epoxy 616 disposed on and in each of the battery contact pads 604a and 604b from the top surface of the folding arm 626 in the same or similar manner as described above with respect to FIGURES 2, 3, 4B, and 5. Similarly, the batteries 614a and 614b can be mechanically and electrically coupled to the top surface 608 of the flexible PCB 602 by applying and curing a conductive UV-curable epoxy 616 disposed on and in each of the battery contact pads 604c and 604d from the bottom surface 610 of the flexible PCB 602 in the same or similar manner as described above with respect to FIGURES 2, 3, 4B, and 5. It should be noted that the curing of the conductive UV-curable epoxy 616 in and on the battery contact pads 604a-604d with UV light can be performed simultaneously or in any suitable order.

[0047] FIG. 7 illustrates a flexible PCB material 700 configured to optimize automated manufacturing of flexible PCBs with foldable arms, such as flexible PCB 602, according to one or more embodiments. As shown, flexible PCB material 700 may be configured with closely spaced groups of flexible PCBs 702a-702d to minimize unused PCB material. Each flexible PCB 702a-702d may include four battery contact pads 704a-704d (only one group of battery contact pads is shown in FIG. 7) to accommodate two coin-cell (or similarly configured) batteries. Another embodiment configured for a single battery may include only two battery contact pads, e.g., battery contact pads 704a and 704d. Each of battery contact pads 704a-704d may be similar to or identical to battery contact pad 104. Each flexible PCB 702a-702d can also include a foldable arm 726 (only one shown), which may be similar to or identical to foldable arm 626. Each flexible PCB 702a-702d can further include printed conductors 712a and 712b (only one of each shown), where printed conductors 712a are formed on one surface of foldable arm 726 for interconnecting with battery contact pads 704c and 704d, and printed conductors 712b are formed on the opposite surface of foldable arm 726 for similarly interconnecting with battery contact pads 704c and 704d. Although a single row of four flexible PCBs 702a-702d is shown in FIG. 7, other embodiments of PCB material may include other numbers of rows and / or closely spaced groupings of flexible PCBs, based on the configuration shown.

[0048] FIG. 8 illustrates a flexible PCB configuration 800 including an attachable arm 826 configured to attach and electrically connect a pair of coin cell batteries 814 a and 814 b (or similarly configured batteries) to a flexible PCB 802, according to one or more embodiments. The batteries 814 a and 814 b may be positioned on respective battery contact pads (not shown) formed on the flexible PCB 802 at a top surface 808 of the flexible PCB 802. Each of the battery contact pads formed on the flexible PCB 802 may be similar to or identical to the battery contact pads 104 of FIGS. 1A and 1B. In embodiments where some rigidity is desired in the area where one or more batteries are attached to facilitate the assembly process of the flexible PCB 802, a non-conductive battery stiffener 828 may be used to hold the batteries 814 a and 814 b. The battery stiffener 828 may be the same as or similar to the battery stiffener 626 of FIG. 6.

[0049] As shown in FIG. 9 , the attachable arm 826 is a separate component having battery contact pads 904 a and 904 b formed therein, which can be connected to one another by printed conductors 912 a on one surface of the attachable arm 826 and, in some embodiments, by printed conductors (not shown) on the opposite surface of the attachable arm 826. Each of the battery contact pads 904 a and 904 b may be similar to or identical to the battery contact pads 104. The attachable arm 826 may also include a single-ended termination 930 formed at one end of the attachable arm 826 that is configured to be inserted into a connector 832 mounted on the top surface 808 of the flexible PCB 802. In the two-battery embodiment shown in FIG. 8 , the coupling of the single-ended termination 930 to the connector 832 may be merely a physical coupling (there is no electrical connection at the connector 832). In another embodiment using only a single battery, the coupling of single-ended termination 930 to connector 832 can be a physical and electrical connection (to complete the circuit with the single battery), and attachable arm 826 can include printed conductors extending from the battery contact pads to single-ended termination 930 for electrical connection from the top surface terminal of the battery through connector 832 to circuitry imprinted on top surface 808. In some embodiments, connector 832 can be an FPC (flexible printed circuit) connector. Other suitable connectors may be used. The shape of attachable arm 826 and the placement of connector 832 on top surface 808 are configured such that, when inserted into connector 832, attachable arm 826 includes battery contact pad 904a positioned over battery 814a and battery contact pad 904b positioned over battery 814b. Other shapes of attachable arm 826 and placement of connector 832 are possible.In those embodiments in which only a single battery is used, the attachable arm 826 and flexible PCB 802 may each include only one suitably positioned battery contact pad, and the length and / or shape of the attachable arm 826 and the placement of the connector 832 may be adjusted accordingly. The attachable arm 826 may be made of the same flexible PCB material as the flexible PCB 802. Alternatively, other suitable materials may be used to manufacture the attachable arm 826.

[0050] To complete the mechanical and electrical coupling of the attachable arm 826 to the batteries 814a and 814b, a conductive UV-curable epoxy, such as conductive UV-curable epoxy 216 or 616, can be disposed and cured on and into each of the battery contact pads 904a and 904b from the top surface 908 of the attachable arm 826 in the same or similar manner as described above in connection with Figures 2, 3, 4B, 5, and 6C. Similarly, the batteries 814a and 814b can be mechanically and electrically coupled to the top surface 808 of the flexible PCB 802 by the application and curing of a conductive UV-curable epoxy disposed on and into each of the battery contact pads formed on the flexible PCB 802 from the bottom surface of the flexible PCB 802 in the same or similar manner as described above in connection with Figures 2, 3, 4B, 5, and 6C. It should be noted that the curing of the conductive UV-curable epoxy in and on the battery contact pads 904a, 904b, and the two battery contact pads formed on the flexible PCB 802 by UV light, can be performed simultaneously or in any suitable order.

[0051] FIG. 10 illustrates a method 1000 of attaching a coin cell (or similarly configured) battery to a flexible PCB with arms, according to one or more embodiments. At process block 1002, method 1000 may include providing a flexible PCB with at least one battery contact pad formed therein. For example, as shown in FIG. 11 , flexible PCB 1102 may have one or more battery contact pads 1104 a and / or 1104 b formed therein. Each of battery contact pads 1104 a and 1104 b may be similar to or identical to battery contact pad 104.

[0052] At process block 1004, method 1000 may include placing at least one coin cell battery (or a similarly configured battery) on at least one battery contact pad on the flexible PCB. When mounting two or more batteries on the flexible PCB, each battery is positioned on a respective battery contact pad. For example, as shown in FIGS. 6A, 6B, and 8, one or more batteries 614a, 614b, 814a, and / or 814b may be positioned on a battery contact pad on each flexible PCB 602 or 802. When mounting two batteries (e.g., batteries 614a and 614b or batteries 814a and 814b), battery stiffeners 628 or 828 may be used to add rigidity to the battery mounting area of ​​the flexible PCB, if necessary.

[0053] At process block 1006, method 1000 can include disposing an arm overlying at least one battery, the arm having at least one battery contact pad formed therein and overlying the at least one battery. When two or more batteries are mounted on the flexible PCB, the arm has a respective battery contact pad formed therein for each battery. The battery contact pads are suitably spaced apart from one another on the arm so as to be positioned below the arm and above the respective battery. One or more printed conductors formed on the arm can electrically connect the battery contact pads to one another. Referring to FIGS. 6A-6C, 8, and 9, the arm can be, for example, a foldable arm 626 or an attachable arm 826. In those embodiments in which the arm is a foldable arm 626, the method 1000 at process block 1006 includes folding the foldable arm 626 so that the arm is positioned over at least one battery and one or more battery contact pads of the foldable arm 626 are positioned over the one or more battery cells, respectively, as shown in Figures 6B and 6C. In those embodiments in which the arm is an attachable arm 826, the method 1000 at process block 1006 includes inserting the single-ended termination 930 of the attachable arm 826 into the connector 832 so that the attachable arm 826 is positioned over at least one battery cell and one or more battery contact pads of the attachable arm 826 are positioned over the one or more battery cells, respectively, as shown in Figure 8.

[0054] At process block 1008, method 1000 may include applying a conductive UV-curable epoxy to the accessible side of each contact pad such that the epoxy fills the metallized vias of each contact pad and contacts the cell surface, similar to that described above in connection with process block 506 of method 500 (FIG. 5).

[0055] Then, at process block 1010, method 1000 may include irradiating each battery contact pad with ultraviolet light to cure the conductive UV-curable epoxy, similar to that described above in connection with process block 508 (FIG. 5) of method 500. As a result, mechanical and electrical connections are established between the batteries and the battery contact pads formed on the arms and flexible PCB.

[0056] 12 illustrates a continuous glucose monitor (CGM) wireless transmitter 1200 with a flexible PCB according to one or more embodiments. The CGM wireless transmitter 1200 comprises a flexible PCB 1202 with one or more batteries 1204 mounted thereon. The one or more batteries 1204 may be mounted on and electrically connected to the flexible PCB 1202 in any manner shown in FIGS. 2, 4B, 6B, 6C, and / or 8. The CGM wireless transmitter 1200 also includes a blood glucose sensor 1234 and wireless transmitter circuitry 1236, each fabricated on the top surface 1208 (or alternatively on the bottom surface) of the flexible PCB 1202, and electrically connected to each other, the one or more batteries 1204, and possibly to other circuits or components (not shown) by printed conductors 1212a, 1212b, and 1212c. A portion of the blood glucose sensor 1234 can be configured to be inserted into the skin of a user's body and continuously measure blood glucose levels, and the wireless transmitter circuit 1236 can be configured to wirelessly transmit those glucose measurements to a CGM receiver and / or insulin pump. Other circuits and circuit components (not shown) may also be fabricated on the flexible PCB 1202. Advantageously, the CGM wireless transmitter 1200 can fold and / or bend to conform to the surface of the user's body to which it is attached, improving adhesion of the CGM wireless transmitter 1200 to the skin surface and / or the user's comfort while wearing the CGM wireless transmitter 1200.

[0057] In some embodiments, other light-curable epoxies may be used, such as epoxies that can be cured at other wavelengths (e.g., mid-UV light, near-UV light, violet light, blue light, or other visible wavelengths). For example, in some embodiments, methods 300, 500, 1000 can be used with other light-curable epoxies, as well as any of the circuit board configurations described herein.

[0058] While the disclosure is susceptible to various modifications and alternative forms, specific method and apparatus embodiments have been shown by way of example in the drawings and are herein described in detail. It is to be understood, however, that the specific methods and apparatus disclosed herein are not intended to limit the disclosure, but on the contrary, are intended to cover all modifications, equivalents, and alternatives falling within the scope of the appended claims.

Claims

1. 1. A method of installing at least one battery, the method comprising:

1. A flexible printed circuit board (PCB), comprising: a pattern of metallized vias extending through the flexible PCB from a first surface to an opposite second surface of the flexible PCB; at least one contact pad; and disposing the at least one battery on the flexible PCB and on the at least one contact pad; applying a conductive light-curable epoxy onto and into the at least one metallized via on the first surface such that the conductive light-curable epoxy contacts and adheres to the at least one battery cell and provides a conductive path from the at least one battery cell to at least one metallized via in the pattern of metallized vias; irradiating the conductive photocurable epoxy with light to cure the conductive photocurable epoxy; A method comprising:

2. disposing an arm over the at least one battery cell, the arm having at least one battery contact pad on the at least one battery cell; The method of claim 1 further comprising:

3. forming one or more printed conductors on said arm; The method of claim 2 further comprising:

4. The method of claim 1 , wherein the at least one battery comprises a coin cell battery.

5. forming a printed conductor on the first surface, the printed conductor surrounding and electrically connecting the pattern of metallized vias; The method of claim 1 further comprising:

6. The method of claim 5 , wherein the conductive light-curable epoxy provides a conductive path from the at least one cell to the printed conductor.

7. The method of claim 1 , wherein the conductive light-curable epoxy comprises a conductive ultraviolet-curable epoxy and the light comprises ultraviolet light.

8. The method of claim 1 , wherein the at least one battery is disposed on the at least one contact pad without a battery holder.

9. 1. A method of attaching at least one electronic component, the method comprising:

1. A flexible printed circuit board (PCB), comprising: a pattern of metallized vias extending through the flexible PCB from a first surface to an opposite second surface of the flexible PCB; at least one contact pad; and disposing the at least one electronic component on the flexible PCB and onto the at least one contact pad; applying a conductive light-curable epoxy onto and into the at least one metallized via on the first surface such that the conductive light-curable epoxy contacts and adheres to the at least one electronic component and provides a conductive path from the at least one electronic component to at least one metallized via in the pattern of metallized vias; irradiating the conductive photocurable epoxy with light to cure the conductive photocurable epoxy; A method comprising:

10. The method of claim 9 , wherein the at least one electronic component comprises a coin cell battery.

11. forming a printed conductor on the first surface, the printed conductor surrounding and electrically connecting the pattern of metallized vias; The method of claim 9 further comprising:

12. The method of claim 11 , wherein the conductive light-curable epoxy provides a conductive path from the at least one electronic component to the printed conductor.

13. applying a subsequent conductive photocurable epoxy onto and into at least one subsequent metallized via of the pattern of metallized vias on the first surface; The method of claim 9 further comprising:

14. 14. The method of claim 13, wherein the conductive photocurable epoxy and the subsequent conductive photocurable epoxy are simultaneously illuminated by a single ultraviolet lighting device.

15. After irradiating the conductive photocurable epoxy with light, the subsequent conductive photocurable epoxy is sequentially irradiated with light to sequentially cure the subsequent conductive photocurable epoxy. The method of claim 13 further comprising:

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