FIELD OF THE INVENTION

The present disclosure is directed generally to implantable devices. More particularly, but not exclusively, various methods and apparatus disclosed herein relate to powering subcutaneous implantable devices using electromagnetic radiation.

BACKGROUND OF THE INVENTION

Implantable devices are becoming increasingly common. For example, pacemakers have long been implanted into patients to regulate heartbeat. Subcutaneous implantable medical devices are being increasingly used to administer treatments and/or monitor one or more biomarkers. For example, some subcutaneous implantable medical devices are used to monitor glucose and/or administer insulin. Other subcutaneous implantable medical devices may be used to monitor other biomarkers, such as sweat (e.g., as a proxy for stress levels), inter-cell fluid flow, heart rate, and so forth. Yet other

subcutaneous implantable medical devices may be used as contraceptives, e.g. , administering hormones for some period of months or years after implantation. It is a goal of medical device manufacturers to make subcutaneous implantable devices as small (e.g. , thin) and simple as possible, for both medical and economic reasons. However, incorporating power sources such as batteries into subcutaneous implantable medical devices undermines this goal. While photovoltaic cells can be constructed to be small and biocompatible, their usefulness in powering subcutaneous implantable medical devices has been limited thus far by suboptimal light conversion of the skin.

SUMMARY OF THE INVENTION

The present disclosure is directed to methods and apparatus for powering subcutaneous implantable devices using electromagnetic radiation. In various

implementations, a subcutaneous implantable device may be electrically coupled with one or more optical energy harvesting devices, such as photovoltaic cells. Various optical elements may be used to enhance incoupling of electromagnetic radiation (i.e. light) that is incident to a patient's skin towards the one or more optical energy harvesting devices. Additionally or alternatively, other mechanisms such as waveguides may be employed to concentrate and/or guide electromagnetic radiation to a subcutaneous depth at which the one or more optical energy harvesting devices are located. In some embodiments, natural anatomical pathways of the patient may be leveraged using various mechanisms to capture and concentrate light towards the one or more optical energy harvesting devices. In many instances, subcutaneous implantable devices are medical in nature, e.g. , providing treatments to patients and/or measuring various biomarkers. However, other subcutaneous implantable devices may be used for other purposes, such as homing beacons (e.g. , to track the location of individuals).

Generally, in one aspect, a system may include: a subcutaneous implantable device; one or more optical energy harvesting devices electrically coupled to the

subcutaneous implantable device, wherein the one or more optical energy harvesting devices convert electromagnetic radiation propagating beneath an outer surface of an individual's skin into electrical energy used to power the subcutaneous implantable device; and an incou ling optical element that is securable to the outer surface of the individual's skin to capture incident electromagnetic radiation from an external environment and direct the captured electromagnetic radiation to the one or more optical energy harvesting devices.

In some embodiments, the one or more optical energy harvesting devices may include two or more photovoltaic cells that are positioned on opposite exterior surfaces of the subcutaneous implantable device. In various versions, the two or more photovoltaic cells may include a first photovoltaic cell secured on an exterior surface of the subcutaneous implantable device to face an outer surface of an individual's skin. In various versions, a second photovoltaic cell may convert electromagnetic radiation reflected from one or more anatomical structures beneath the subcutaneous implantable device into electrical energy used to power the subcutaneous implantable device. In some embodiments, the subcutaneous implantable medical device may include an interior reflective surface, and the first and/or second photovoltaic cell may capture electromagnetic radiation reflected from the reflective surface. In some embodiments, the first photovoltaic cell may be sensitive to a first color, the second photovoltaic cell may be sensitive to a second color that is different from the first color, and the incoupling optical element may concentrate electromagnetic radiation of the first color towards the first photovoltaic cell and may be positioned relative the first and second photovoltaic cells to permit electromagnetic radiation of the second color to propagate to the second photovoltaic cell.

In various embodiments, the incoupling optical element may be securable to the outer surface of the individual's skin without puncturing the individual's skin. In various embodiments, the incoupling optical element may include one or more hemispherical lenses with flat portions that face the outer surface of the individual's skin. In various

embodiments, the incoupling optical element may include a multi-layer incoupling structure, wherein one of more layers of the multi-layer incoupling structure have refractive indices selected to direct captured incident electromagnetic radiation towards the one or more optical energy harvesting devices.

In various embodiments, the incoupling optical element may include one or more Fresnel lenses. In various embodiments, the system may include a shallow and rigid waveguide that may be insertable beneath the outer surface of the individual's skin to optically couple the incoupling optical element and the optical energy harvesting devices. In various versions, the shallow and rigid waveguide may include an interior reflective surface that is reflective. In various versions, the shallow and rigid waveguide may have a frustrum shape with a first end positionable adjacent the incoupling optical element and a second end that is positionable adjacent the one or more optical energy harvesting devices, wherein the first end is wider than the second end.

In various embodiments, the one or more optical energy harvesting devices may include at least one photovoltaic cell positionable between the subcutaneous implantable device and the outer surface of the individual's skin. In various embodiments, the optical element may filter the incident electromagnetic radiation to direct blue light towards the at least one photovoltaic cell. In various embodiments, the system may include a transverse waveguide to capture electromagnetic radiation scattered beneath the outer surface of the individual's skin in a direction that is transverse to a normal of the outer surface of the individual's skin.

In another aspect, an apparatus may include: a subcutaneous implantable device; at least one optical energy harvesting device electrically coupled to the subcutaneous implantable device, wherein the at least one optical energy harvesting device is positioned on an exterior surface of the subcutaneous implantable device to face an outer surface of an individual's skin to convert electromagnetic radiation propagating beneath the outer surface of the individual's skin into electrical energy used to power the subcutaneous implantable device; and a rigid and shallow waveguide positionable between the outer surface of the individual's skin and the at least one optical energy harvesting device to optically couple the outer surface of the individual's skin with the optical energy harvesting device.

In another aspect, there is provided a subcutaneous implantable device configured to be powered by electromagnetic radiation captured from an external environment, wherein the electromagnetic radiation is incident on and propagates beneath an outer surface of an individual's skin.

In various embodiments, the subcutaneous implantable device may be configured to electrically couple to one or more optical energy harvesting devices that are operable to convert the electromagnetic radiation propagating beneath the outer surface of the individual's skin into electrical energy and the subcutaneous implantable device may be configured to be powered by the electrical energy.

In various embodiments, the one or more optical energy harvesting devices may be positioned on an exterior surface of the subcutaneous implantable device to face the outer surface of the individual's skin.

In various embodiments, the electromagnetic radiation may be captured from the external environment by an incoupling optical element that is securable to the outer surface of the individual's skin.

In various embodiments, the captured electromagnetic radiation may be directed to one or more optical energy harvesting devices by the incoupling optical element.

In various embodiments, a rigid and shallow waveguide may be positionable between the outer surface of the individual's skin and one or more optical energy harvesting devices to optically couple the outer surface of the individual's skin with one or more optical energy harvesting devices.

In another aspect, there is porvided an incoupling optical element, wherein the incoupling optical element is securable to an outer surface of an individual's skin. The incoupling optical element is configured to capture electromagnetic radiation from an external environment that is incident on the individual's skin and direct the captured electromagnetic radiation to one or more optical energy harvesting devices that are configured to electrically couple to and power a subcutaneous implantable device.

In various embodiments, the one or more optical energy harvesting devices may be operable to convert the electromagnetic radiation that propagates beneath the outer surface of the individual's skin into electrical energy that is used to power the subcutaneous implantable device.

In various embodiments, the one or more optical energy harvesting devices may be positioned on an exterior surface of the subcutaneous implantable device to face the outer surface of the individual's skin.

In various embodiments, a rigid and shallow waveguide may be positionable between the outer surface of the individual's skin and the one or more optical energy harvesting devices to optically couple the outer surface of the individual's skin with the one or more optical energy harvesting devices.

It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the disclosure.

Figs. 1-8 depict example arrangements of various components described herein, in accordance with various embodiments.

Fig. 9 depicts an example method for powering subcutaneous implantable devices using electromagnetic radiation, in accordance with various embodiments.

DETAILED DESCRIPTION OF EMBODIMENTS

Subcutaneous implantable devices are being increasingly used for medical and other purposes. It may be beneficial to make subcutaneous implantable devices as small and simple as possible, for both medical and economic reasons. However, incorporating power sources such as batteries into subcutaneous implantable devices undermines this goal. While photovoltaic cells can be constructed to be small and biocompatible, their usefulness in powering subcutaneous implantable devices has been limited thus far by suboptimal light conversion of the skin. Accordingly, techniques, systems, and apparatus described herein are provided for powering subcutaneous implantable devices using electromagnetic radiation. More particularly, various systems, apparatus, and techniques described herein relate to enhancing capture (also referred to as "incoupling"), concentration, and direction of electromagnetic radiation (i.e. light) towards one or more optical energy harvesting devices, such as photovoltaic cells, powering a subcutaneous implantable device. In various embodiments, the subcutaneous implantable device can powered passively by electrical energy produced from environmental (i.e. ambient or atmospheric) electromagnetic radiation. While the description set forth herein describes many of the embodiments as subcutaneous implantable "medical" devices, this is not meant to be limiting. Techniques described herein may be used to power any subcutaneous implantable device, whether medical -related or otherwise.

Referring to Fig. 1, a subcutaneous implantable medical device 100 may be implanted in a patient's skin, for example in the dermis layer 102, which may be between the epidermis 104 and fatty tissue 106. Dermis 102 may be separated from epidermis 104 by a layer of melanin 108. Subcutaneous implantable medical device 100 may come in various forms. In some embodiments, subcutaneous implantable medical device 100 may take the form of various monitoring devices for monitoring biomarkers such as, for instance, glucose levels, sweat, heartrate and other vital signs, inter-cell fluid flow, and so forth. In other embodiments, subcutaneous implantable medical device 100 may be configured to administer various treatments to a patient, such as contraceptives (e.g. , hormones), insulin, and so forth. And as mentioned above, a non-medical subcutaneous implantable device may also be powered using disclosed techniques.

In various embodiments, subcutaneous implantable medical device 100 may be electrically coupled to one or more optical energy harvesting devices, such as one or more photovoltaic cells 110. Photovoltaic cells 110 may take various forms, such as photodiodes, photo-transducers, or any other device that converts electromagnetic radiation into electrical energy. Photovoltaic cells 110 may be coated with various transparent and/or biocompatible materials that act as moisture and/or dielectric barriers. In some embodiments, for instance, photovoltaic cell 110 may be coated with a variety of chemical vapor deposited poly(- xylylene) polymers, such as Parylene™. In some embodiments, photovoltaic cell 1 10 may be positioned between subcutaneous implantable medical device 100 and an outer surface

1 14 of the patient's skin so that it can harvest electromagnetic radiation 1 16 that is incident to outer surface 1 14 of the patient's skin. While not depicted in the Figures, in various embodiments, photovoltaic cells 110 may be used to recharge a battery contained in subcutaneous implantable device 100.

As can be seen in the left-most and right-most arrows, incident electromagnetic radiation 1 16 may, upon contacting outer surface 1 14 of the patient's skin, be reflected in various directions, including away from outer surface 114. As a consequence of this reflection, much of incident electromagnetic radiation 116 may not make its way to photovoltaic cell 110, and therefore may not be harvested. Accordingly, in various embodiments, an incoupling optical element 118 may be secured to outer surface 114 of the patient's skin, e.g., using various biocompatible adhesives, biocompatible stitching, or other similar means, to capture incident electromagnetic radiation 116 from an external

environment and direct the captured electromagnetic radiation to photovoltaic cell 110. In some embodiments, incoupling optical element 1 18 may be secured to the patient's skin without puncturing the skin. In other embodiments described herein that employ waveguides (e.g., Figs. 4-6, 8), the patient's skin may be punctured. As shown by the arrows between incoupling optical element 118 and photovoltaic cell 110, much of incident electromagnetic radiation 116 that is captured by incoupling optical element 118 makes its way towards photovoltaic cell 110, rather than being reflected away from outer surface 1 14 of the patient's skin.

In Fig. 1, incoupling optical element 118 includes one or more hemispherical lenses 120 with flat portions that face and/or contact the outer surface 1 14 of the patient's skin. In some implementations, hemispherical lenses 120 may be constructed with transparent materials traditionally used for lenses, such as glass or polymers. In some embodiments, polymers may be preferable because they may be constructed to be more flexible than, say, glass, and therefore may better conform to outer surface 114 of the patient's skin.

In alternative embodiments, the lenses 120 may be formed with the patient's sweat. For example, a plurality of nucleation points may be provided on a glass or polymer substrate for drop formation. Nucleation points may include, for instance, topographic features such as small extensions. In some embodiments, nucleation points may be formed by adapting surface tension properties of incoupling optical element 118 such that there are alternating regions with hydrophobic and hydrophilic properties. In such embodiments, drops will form on the hydrophilic areas.

Embodiments described herein are not limited to the hemispherical lens mechanism of Fig. 1. For example, Fig. 2 depicts an arrangement of components very similar to those of Fig. 1, except that instead of incoupling optical element 118 including a plurality of hemispherical elements 120, incoupling optical element 118 takes the form of an anti-reflective, multi-layer incoupling structure (i.e., an optical cavity) 118. One of more of the layers may have refractive indices selected to capture and direct captured incident electromagnetic radiation towards the one or more photovoltaic cells 110. The various layers of multi-layer incoupling optical element 118 may be constructed with various materials, including but not limited to silicone oxides, silicone nitrites, titanium oxides, and so forth. Similar to the arrangement of Fig. 1, and as shown by the arrows between multi-layer incoupling optical element 118 and photovoltaic cell 110, much of incident electromagnetic radiation 116 that is captured by multi-layer incoupling optical element 118 makes its way towards photovoltaic cell 110, rather than being reflected away from outer surface 114 of the patient's skin.

In various embodiments, either type of incoupling optical element may be manually or automatically adapted to changing lighting conditions. For example, hemispherical lens 120 may be rearranged and/or selectively covered/made opaque to alter incoming light. Similarly, the multilayer-based incoupling optical element 118 of Fig. 2 may be adjusted in various ways, e.g., to alter refractive indices within and/or between layers.

Fig. 3 depicts an alternative arrangement of components similar to those depicted in Figs. 1 and 2. While the embodiment of Fig. 3 is depicted with a multi-layer incoupling optical element 118 similar to that depicted in Fig. 2, it could just as easily include the multi-hemispherical-element incoupling optical element 118 of Fig. 1. In Fig. 3, two photovoltaic cells, 110A and 110B, are positioned on opposite exterior surfaces of subcutaneous implantable medical device 100 to convert electromagnetic radiation propagating beneath outer surface 1 14 of the patient's skin into electrical energy used to power subcutaneous implantable medical device 100. First photovoltaic cell 11 OA operates much in the same way as photovoltaic cells 110 of Figs. 1 and 2. However, second photovoltaic cell HOB may serve a slightly different purpose.

For example, in some implementations, second photovoltaic cell HOB may convert electromagnetic radiation 121 that has reflected from (or has scattered from) one or more anatomical structures beneath subcutaneous implantable medical device 100 into electrical energy used to power subcutaneous implantable medical device 100. In Fig. 3, the anatomic structure takes the form of bone 122. However, this is not meant to be limiting. Electromagnetic radiation scattered internally in the patient's body may be reflected off or scattered from other anatomic structures, such as fatty tissue (which may be highly scattering), epidermal layer boundaries, organs, arteries, veins, and so forth.

Fig. 4 depicts another embodiment similar to that depicted in Fig. 1, except that a shallow waveguide 124 has been added between incoupling optical element 118 and photovoltaic cell 110. In some embodiments, shallow waveguide 124 may have a frustrum shape, and may be wider at the top than at the bottom, although this is not required, and the top could be narrower than, or equal in diameter to, the bottom as well. Because

subcutaneous implantable device 100 is not implanted far beneath the skin, in some embodiments, shallow waveguide 124 may be rigid. Shallow waveguide 124 may optically couple incoupling optical element 118 and the photovoltaic cell 110 to increase harvesting of electromagnetic radiation, e.g. , by decreasing the amount of electromagnetic radiation that may be scattered between incoupling optical element 118 and photovoltaic cell 110. While the embodiment of Fig. 4 is depicted with multi-hemispherical-element incoupling optical element 118 of Fig. 1, it could just as easily include the multi-layer incoupling optical element 118 similar to that depicted in Figs. 2 and 3. In various embodiments, waveguide 124 may or may not include one or more optical filters, e.g., to permit passage of one or more colors of electromagnetic radiation.

The "shallow" waveguide 124 is so-named because of the subcutaneous nature of subcutaneous implantable medical device 100. In particular, subcutaneous implantable medical device 100 is implanted in dermis 102, which is not particularly far beneath outer surface 1 14 of the patient's skin. Accordingly, a waveguide 124 suitable for optically coupling photovoltaic cell 110 and incoupling optical element 118 may only be required to pass through the epidermis 104 in order to create an optical coupling between incoupling optical element 118 and photovoltaic cell 110. For example, in some embodiments, shallow waveguide 124 may be as small as a few hundred microns in height, to as large as a few millimeters. In some embodiments, shallow waveguide 124 may have a width (or diameter) in similar ranges. In various embodiments, shallow waveguide 124 may be open (e.g., filled with air or a vacuum) or filled with various types of transparent polymers or glass.

Fig. 5 depicts another example embodiment with components similar to those depicted in various previously-discussed Figures. In this example, incoupling optical element 118 (which is in the multi-layer form described previously but could just as easily be the hemisphere-based form) is optically coupled to first photovoltaic cell 110A via shallow waveguide 124. Incoupling optical element 118 in this embodiment acts as an optical filter that allows blue electromagnetic radiation (indicated by the dashed lines) to pass through to first photovoltaic cell 110A, which may be constructed to be sensitive to blue light.

Red electromagnetic radiation (or "near infrared"), on the other hand, may be capable of penetrating further into the patient's skin. Accordingly, incoupling optical element 118 and waveguide 124 are only positioned over part (on the left) of subcutaneous implantable medical device 100. The right-hand side of subcutaneous implantable medical device 100 is left exposed to red electromagnetic radiation (as indicated by the dash-dot-dash lines) that is able to penetrate all the way down to second photovoltaic cell HOB (which may be constructed to be extra sensitive to red light). In some embodiments, first photovoltaic cell 110A may also capture some of the red electromagnetic radiation, although it also may be made transparent (at least to red electromagnetic radiation) or sufficiently thin such that red electromagnetic radiation passes through to second photovoltaic cell HOB. Of course, in other embodiments, a second incoupling optical element may be positioned over the exposed right side of subcutaneous implantable medical device 100, and may be designed to capture and pass red electromagnetic radiation to first photovoltaic cell 11 OA and/or second photovoltaic cell HOB.

Fig. 6 depicts an alternative embodiment in which both a multi-layer incoupling optical element 118A and a multi -hemisphere-based incoupling optical element 118B are employed side-by-side over subcutaneous implantable medical device 100. But this is not meant to be limiting, and multiple homogenous incoupling optical elements 118 may be employed side -by-side as well. In this example, both incoupling optical elements 118 are operably coupled with first photovoltaic cell 110A via respective waveguides 124A and 124B, but this is not required, and only one, or neither, incoupling optical element 118 may be coupled with a waveguide 124.

In this example, subcutaneous implantable medical device 100 includes a transverse waveguide 130 positioned below first photovoltaic cell 110A to capture electromagnetic radiation 132 scattered beneath outer surface 1 14 of the patient's skin in a direction that is transverse to a normal of outer surface 1 14 of the patient's skin. In various implementations, transverse waveguide 130 may have reflective interior surfaces, and may take various cross- sectional shapes, such as cylindrical, square shaped, and so forth.

Waveguide 130 may be open (e.g., filled with air or a vacuum) or filled with various types of transparent polymers or glass. In some embodiments, at least one end of transverse waveguide 130 may include endcap photovoltaic cell HOB. While not depicted in Fig. 6, in some embodiments, a third photovoltaic cell may be included on the bottom of subcutaneous implantable medical device 100, as was depicted in Fig. 5. In some such embodiments, an outer surface of transverse waveguide 130 may also be reflective, e.g., to reflect

electromagnetic radiation towards one or both photovoltaic cells. And in some embodiments, subcutaneous implantable medical device 100 may include transverse waveguide 130 by itself and/or without some or all of the other components depicted in Fig. 6 (e.g., 118A, 118B, 124A, 124B, etc).

In some embodiments, various components, such as one or more photovoltaic cells 110 and/or waveguide 130, may be inserted into the human body so that they are optically coupled with one or more naturally occurring anatomical paths or channels through which electromagnetic radiation is more likely to pass. For example, waveguide 130 may be positioned beneath the patient's skin at a point adjacent a sweat gland and/or hair follicle, so that electromagnetic radiation travelling through the gland/follicle may pass into waveguide 130.

Fig. 7 depicts an alternative embodiment in which a different type of incoupling optical element in the form of a lens 140 is affixed and/or adhered (e.g., using stitching or a biocompatible adhesive) to outer surface 1 14 of the patient's skin to focus and direct incident electromagnetic radiation 116 towards photovoltaic cell 110. While a shallow waveguide (e.g. , 124) is not depicted in this example, one may be provided to enhance energy harvesting. In some embodiments, lens 140 may take the form of one more Fresnel lenses, which have the advantage of being relatively slim. Lens 140 may be constructed from various glass or polymers, although polymers may be preferable in some instances because they may be flexible, and therefore may conform better to outer surface 1 14 of the patient's skin.

As is also depicted in Fig. 7, subcutaneous implantable medical device 100 may in some implementations include an interior reflective surface 142. For example, subcutaneous implantable medical device 100 may be at least partially transparent and/or translucent, so that photovoltaic cell 110 may capture electromagnetic radiation reflected upwards from reflective surface 142. While not depicted in the other embodiments, reflective surface 142 may be incorporated into any embodiment herein in order to reflect electromagnetic radiation captured within subcutaneous implantable medical device 100 towards photovoltaic cell 110.

Fig. 8 depicts one example embodiment that incorporates most of the aforementioned mechanisms to capture incident and internally scattered electromagnetic radiation from multiple directions. Accordingly, the embodiment of Fig. 8 includes three photovoltaic cells, 110A, HOB, and HOC. Two reside on opposite exterior surfaces (top and bottom) of subcutaneous implantable medical device 100. The third HOC is positioned on a side of subcutaneous implantable medical device 100 opposite an entry to waveguide 130. Of course, it should be clear that in various embodiments, any combination of one or more of the above-described mechanisms may be deployed in a single patient, e.g. , depending on factors such as the patient's skin health, medical needs, power requirements of subcutaneous implantable medical device 100, and so forth.

Fig. 9 depicts one example method 900 for powering subcutaneous implantable devices using electromagnetic radiation, in accordance with various embodiments. While operations of method 900 are depicted in a particular order, this is not meant to be limiting. Various operations may be added, omitted, or reordered.

At block 902, medical personnel may implant a subcutaneous implantable device (e.g. , 100) beneath an individual's skin, e.g. , in the dermis layer. At block 904, the medical personnel may secure one or more incoupling optical elements (118) to an outer surface of the individual's skin at a position that aims output of the optical element(s) towards one or more photovoltaic cells electrically coupled with the subcutaneously implantable device. As noted above, stitching, biocompatible adhesive, or other similar means (e.g. , belts, medical tape, etc.) may be used to secure the incoupling optical element to the skin.

If desired, and in some cases prior to block 904, at block 906, the medical personnel may optically couple the incoupling optical element with one or more photovoltaic cells using one or more shallow waveguides (e.g., 124). At block 908, the medical personnel may optically couple a transverse waveguide (e.g. , 130) to one or more natural anatomical pathways. In embodiments in which the transverse waveguide is integral with the subcutaneous implantable device, the operation of block 908 may be performed when the subcutaneous implantable device is implanted at block 902.

Once the one or more mechanisms are installed/implanted, at block 910, the photovoltaic cell(s) may begin converting captured electromagnetic radiation into power for the subcutaneous implantable device. In some embodiments, medical personnel or the individual may be able to, at block 912, modulate light provided to photovoltaic cells to alter a state of the subcutaneous implantable device. For example, an individual or medical personnel may hold a smart phone or watch near an incoupling optical element and operate an application to cause modulated light to be emitted from an LED (e.g. , a flash). The modulated light may include instructions that, when interpreted by logic in the subcutaneous implantable device, cause the subcutaneous implantable device to change its state (e.g. , turn on, turn off, reset, set alarm thresholds, etc.).

While several embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, embodiments may be practiced otherwise than as specifically described and claimed. Embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the scope of the present disclosure.

All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.

The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

The phrase "and/or," as used herein in the specification and in the claims, should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases.

Multiple elements listed with "and/or" should be construed in the same fashion, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the "and/or" clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to "A and/or B", when used in conjunction with open-ended language such as "comprising" can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

As used herein in the specification and in the claims, "or" should be understood to have the same meaning as "and/or" as defined above. For example, when separating items in a list, "or" or "and/or" shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as "only one of or "exactly one of," or, when used in the claims, "consisting of," will refer to the inclusion of exactly one element of a number or list of elements. In general, the term "or" as used herein shall only be interpreted as indicating exclusive alternatives (i.e. "one or the other but not both") when preceded by terms of exclusivity, such as "either," "one of," "only one of," or "exactly one of." "Consisting essentially of," when used in the claims, shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase "at least one" refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B," or, equivalently "at least one of A and/or B") can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

In the claims, as well as in the specification above, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "composed of," and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of and "consisting essentially of shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03. It should be understood that certain expressions and reference signs used in the claims pursuant to Rule 6.2(b) of the Patent Cooperation Treaty ("PCT") do not limit the scope.