Patent Application
20190038455
In recent years there has been a growing interest for active medical technologies that leverage the increasing computational power of portable computers, smartphones, and tablets. For example, body mountable thermal coupling devices (or patches) that measure and track the temperature of a user's body currently exist. These devices can, and often are, worn for lengthy periods of time, e.g., a 24-hour period.
Examples discussed herein relate to body mountable thermal coupling devices and, more specifically, to body mountable thermal coupling apparatuses with resistance to varying ambient conditions. In an implementation, a body mountable thermal coupling apparatus is disclosed. The apparatus includes a bio-compatible thermally conductive metal disc embedded in or otherwise attached to an enclosure, a substrate, a thermal sensor, an enclosure, and an adhesive patch. The bio-compatible thermally conductive metal disc has a proximal surface for thermally coupling with the skin of a user. The substrate has a proximal surface with an exposed conductive pad thermally coupled to a distal surface of the metal disc. The substrate includes one or more through-substrate vias filled with thermally conductive material.
The thermal sensor is disposed on a distal surface of the substrate and is thermally coupled to one or more through-substrate vias. The enclosure includes distal and proximal portions for encasing the substrate. The adhesive patch is affixed to a proximal surface of the proximal (or bottom) portion of the enclosure. The adhesive patch includes an opening (or cutout) for the metal disc and a bio-compatible adhesive on the proximal surface for removably attaching the apparatus to the skin of the user.
This Overview is provided to introduce a selection of concepts in a simplified form that are further described below in the Technical Disclosure. It may be understood that this Overview is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
A detailed description is set forth and will be rendered by reference to specific examples thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical examples and are not therefore to be considered to be limiting of its scope, implementations will be described and explained with additional specificity and detail through the use of the accompanying drawings.
The drawings have not necessarily been drawn to scale. Similarly, some components and/or operations may be separated into different blocks or combined into a single block for the purposes of discussion of some of the embodiments of the present technology. Moreover, while the technology is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the technology to the particular embodiments described. On the contrary, the technology is intended to cover all modifications, equivalents, and alternatives falling within the scope of the technology as defined by the appended claims.
Examples are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the subject matter of this disclosure. The implementations may include machine-implemented methods, computing devices, or computer readable medium.
Body mountable thermal coupling devices (or patches) that measure and track the temperature of a user's body can, and often are, worn for lengthy periods of time, e.g., 24-hour periods or longer. With increased length of use comes an increased likelihood that ambient conditions vary during usage. However, existing body mountable devices cannot accurately and reliably estimate core body temperature of a user in environments with varying ambient conditions. For example, variations in ambient temperature, ambient humidity, or even ambient pressure can result in inaccurate core body temperature estimates when using existing body mountable thermal coupling devices (or patches).
Additionally, the existing body mountable thermal coupling devices (or patches) use high accuracy thermistors to measure core body temperature of a user. Unfortunately, the high accuracy thermistors are relatively expensive in terms of cost and can be difficult to place within an apparatus or device. For example, standard thermometers fit the thermistor in a “tip” of the device and package the electronics in a “body” of the device.
The technology described herein is directed to body mountable thermal coupling devices and, more specifically, to body mountable thermal coupling apparatuses with resistance to varying ambient conditions. In some implementations, component stack-ups for ambient condition resistant body mountable thermal coupling apparatuses are described that facilitate thermal coupling between heat from a human body and a thermal (or temperature) sensor. The body mountable thermal coupling apparatuses facilitate proper and reliable thermal coupling without jeopardizing moisture resistance of the electronics enclosure, etc.
In some implementations, heat from the human body is coupled to a thermal sensor on a silicon die through a stack-up including a gold-plated brass disc, a printed circuit board (PCB), and an adhesive patch. The gold-plated brass disc is built into an enclosure to ensure thermal coupling with the skin of a user and with the proximal side of the PCB. The disc can be inserted, molded or glued into the enclosure. As discussed herein, the proximal (or bottom) side or portion of a component is the side or portion that is body facing. Likewise, the distal (or top) side or portion is the opposing side or portion, i.e., not body facing.
The brass disc is thermally coupled with the exposed copper pad on the proximal side of the PCB. In some implementations, thermal grease at the interface ensures uniform contact and improved thermal conductivity. A through-board via filled with conductive epoxy or metal carries heat to the distal side of the PCB where the temperature sensor is mounted. When the sensor is mounted in a particular type of package, e.g., wafer-level chip scale package, thermally conductive underfill can be used to improve the thermal conductivity. The apparatus can be attached to the skin of a user with an adhesive patch including an opening (or cutout) for the brass disc.
As noted above, existing body mountable thermal coupling devices (or patches) use relatively expensive thermistors to sense or measure temperature. Among other benefits, the stack-up described herein facilitates use of silicon thermal sensors for temperature sensing within a device. The silicon thermal sensors are less expensive, easier to place within a device and provide highly accurate thermal readings.
In operation, the thermal coupling device 110 estimates the core body temperature of user 150. Among other benefits, the thermal coupling device 110 is ambient condition resistant and, thus, can be worn and accurately estimate core body temperature of the user 150 for extended periods of time regardless of changes to ambient conditions. Example ambient condition resistant body mountable thermal coupling devices are shown and discussed in greater detail with reference to
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The ambient condition resistant body mountable thermal coupling device 310 further includes a substrate 330 having a proximal surface with an exposed conductive pad 352 thermally coupled to a distal surface of the conductive metal disc 350. The exposed conductive pad 352 can be any conductive surface such as, for example, a copper pad. Additionally, in some implementations, a layer of thermal grease 356 is disposed at the interface between the exposed conductive pad 352 and the distal surface of the conductive metal disc 350 to increase the accuracy of the thermal coupling and reduce loss.
As shown, substrate 330 includes one or more through-substrate vias 332 filled with conductive materials that carry heat from the exposed pad 352 to thermal sensor 340. Thermal sensor 340 can be any sensor that senses temperature, e.g., one or more thermocouples. The sensor cover 342 is disposed on top of (or over) thermal sensor 340 to provide ambient temperature insulation and otherwise reduce ambient thermal coupling by thermal sensor 340. The ambient heat can include, for example, heat from the top of the device, heat from other electronics disposed on substrate 330, etc. The sensor cover 342 can be designed to include a space (or gap) between the sensor cover 342 and the thermal sensor 340 to provide additional insulation. The space can be filled with air or another thermally insulating material such as, for example, foam, etc.
In some implementations, the sensor cover 342 is polished or plated 346 to provide additional insulation. The polish or plating can be on the interior surface of the sensor cover 342 and/or the exterior surface. Although not shown, the distal enclosure portion 325a can alternatively or additionally be polished or plated on the interior and/or the exterior surface to provide insulation.
In some implementations, the substrate 330 includes a microcontroller 344 with an integrated wireless transmitter and a power supply 360. The microcontroller 344 is configured to estimate core body temperature of a user based, at least in part, on the temperature measurements of thermal sensor 340. Additionally, the microcontroller 344 uses input from other sensors (not shown) in addition to the temperature measurements from thermal sensor 340 to compensate and estimate core body temperature of the user.
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In operation, the thermally coupled heat at exposed pad 452 is carried through-substrate via 432 and thermally conductive underfill 433 to the thermal sensor 440. Although not shown in the example of
The ambient condition resistant body mountable thermal coupling device 510 includes many of the components of the ambient condition resistant body mountable thermal coupling device 310 of
In some implementations, the ambient sensor 527 can be thermally coupled to metal insert 526 using mechanisms similar to the mechanisms used to thermally couple metal disc 350 and thermal sensor 340. For example, thermal grease may be applied at the interface between the ambient sensor 527 and the metal insert 526. It is appreciated that the ambient sensor 527 can be mounted in a variety of locations to improve knowledge of ambient temperature. For example, among other locations, the ambient sensor 527 can be mounted on substrate 330, sensor cover 342, or externally on the distal portion of enclosure 325a . Although not shown in the example of
As discussed herein, the ambient sensor 527 senses the ambient temperature and provides this information to microcontroller 344. In some implementations, microcontroller 344 uses the ambient temperature as input to compensation algorithms when estimating core body temperature of the user. As discussed herein, the microcontroller 344 can estimate core body temperature of a user based, at least in part, on the temperature measurements of thermal sensor 340 and ambient sensor 527. Additionally, microcontroller 344 can use input from other sensors (not shown) compensate when estimating core body temperature of a user.
In some implementations, display 626 can illustrate the estimated core body temperature of the user. Display 626 can be included in addition to, or in lieu of, a wireless transmitter that transmits the estimated core body temperature of a user to a remote communication device, e.g., communication device 120 of
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In some implementations, microcontroller 744 executing program code, e.g., a compensation algorithm, from memory 743, samples the one or more sensors 740 and estimates a core body temperature of a user based on the samples. As discussed herein, the one or more sensors 740 can include one or more thermal sensors, humidity sensors, pressure sensors, etc.
The microcontroller 744 can be a small computer or other circuitry that retrieves and executes software from memory 743. The microcontroller 744 may be implemented within a single device or system-on-a-chip (SoC) or may be distributed across multiple processing devices that cooperate in executing program instructions. As shown in the example of
The functional block diagrams, operational scenarios and sequences, and flow diagrams provided in the Figures are representative of exemplary systems, environments, and methodologies for performing novel aspects of the disclosure. While, for purposes of simplicity of explanation, methods included herein may be in the form of a functional diagram, operational scenario or sequence, or flow diagram, and may be described as a series of acts, it is to be understood and appreciated that the methods are not limited by the order of acts, as some acts may, in accordance therewith, occur in a different order and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a method could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all acts illustrated in a methodology may be required for a novel implementation.
The descriptions and figures included herein depict specific implementations to teach those skilled in the art how to make and use the best option. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these implementations that fall within the scope of the invention. Those skilled in the art will also appreciate that the features described above can be combined in various ways to form multiple implementations. As a result, the invention is not limited to the specific implementations described above, but only by the claims and their equivalents.
