WO2016099980A1

WO2016099980A1 - Triaxial cable sensor and wearable devices

Info

Publication number: WO2016099980A1
Application number: PCT/US2015/064276
Authority: WO
Inventors: Robert Jan Visser; Seshadri Ramaswami; Ananth Dodabalapur
Original assignee: Applied Materials, Inc.
Priority date: 2014-12-17
Filing date: 2015-12-07
Publication date: 2016-06-23

Abstract

Triaxial connectors suitable for conveying very low voltage signals on printed circuit boards with flexible substrates and related methods are disclosed. A triaxial connector includes a first conductor on a printed circuit board, two second conductors parallel to the first conductor on different layers of the printed circuit board, with the first conductor between the second conductors, an amplifier configured to amplify an electric signal on the first conductor at unity voltage gain and supply the amplified signal to the two second conductors, and two third conductors maintained at ground potential, wherein the two third conductors are disposed on the printed circuit board parallel to the first conductor and two second conductors, with the first conductor and second conductors between the two third conductors. Sensors may be used without requiring amplifiers and analog-to-digital converters in close proximity, allowing lower-cost sensing devices to be created.

Description

TRIAXIAL CABLE SENSOR AND WEARABLE DEVICES

BACKGROUND

Field

[0001] Embodiments of the present disclosure generally relate to sensors and in particular to triaxial connectors linking sensors with electronic circuitry.

Description of the Related Art

[0002] Developments in medical science and electronic devices have led to developments in devices to sense, record, and interpret a person's biological indications (e.g., temperature, nerve signals, brain waves, etc.). Indications from a person, especially sensed nerve signals, are typically at a very low voltage (e.g., 10 μν to 100 μ\/). Very low voltage signals such as biological indications can be difficult to transmit over even short distances, due to interference (e.g., "noise") that can be induced in the conductors transmitting the very low voltage signals by external factors (e.g., radio waves and other signals). One current technique to transmit very low voltage signals is to place an amplifier and analog-to-digital converter (ADC) in close proximity to the source of the signal, to amplify and digitize the signal for transmission to other components.

[0003] Figure 1 schematically illustrates a system 100 using current techniques for transmitting very low voltage signals from sensors 104 to a controller/processor 102. In the system 100, sensors 104 detect signals and/or indications, and generate signals on output conductors 1 16. The output conductors are connected with amplifiers 1 12 and analog-to-digital converters 1 14, which amplify and digitize the signals. The signals are then conducted to the controller/processor 102. The controller/processor 102 may be connected to an electric power source 106 (e.g., a battery), which may also supply electrical power to the amplifiers and ADCs via other conductors (not shown).

SUMMARY

[0004] According to aspects of the present disclosure, an apparatus for conveying an electric signal is provided. The apparatus generally includes a first conductor disposed on a printed circuit board, two second conductors disposed parallel to the first conductor on different layers of the printed circuit board, wherein the first conductor is between the two second conductors, an amplifier configured to amplify an electric signal on the first conductor at unity voltage gain and supply the amplified signal to the two second conductor, and two third conductors maintained at ground voltage potential, wherein the two third conductors are disposed on the printed circuit board parallel to the first conductor and the two second conductors with the first conductor and second conductors between the two third conductors.

[0005] According to aspects of the present disclosure, an apparatus for conveying a bioelectrical signal is provided. The apparatus generally includes a first conductor disposed on a printed circuit board and connected to a source of the bioelectrical signal, two second conductors disposed parallel to the first conductor on different layers of the printed circuit board, wherein the first conductor is between the two second conductors, an amplifier configured to amplify the bioelectrical signal at unity voltage gain and supply the amplified bioelectrical signal to the two second conductors, and two third conductors maintained at ground voltage potential, wherein the two third conductors are disposed on the printed circuit board parallel to the first conductor and the two second conductors with the first conductor and second conductors between the two third conductors.

[0006] According to aspects of the present disclosure, a method for conveying an electric signal is provided. The method generally includes receiving the electric signal from a first conductor of a printed circuit board, amplifying the electric signal at unity voltage gain, supplying the amplified electric signal to two second conductors disposed on the printed circuit board parallel to the first conductor with the first conductor between the two second conductors, and maintaining two third conductors at ground voltage potential, wherein the two third conductors are disposed on the printed circuit board parallel to the first conductor and second conductors with the first conductor and second conductors between the two third conductors.

[0007] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description that follows, the claims, as well as the appended drawings. [0008] It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, and may admit to other equally effective embodiments.

[0010] Figure 1 schematically illustrates a prior art system.

[0011] Figure 2 schematically illustrates an exemplary system utilizing triaxial conductors to transmit low voltage signals, according to aspects of the present disclosure.

[0012] Figure 3 schematically illustrates an exemplary triaxial conductor, according to aspects of the present disclosure.

[0013] Figure 4 illustrates exemplary operations by a processor, according to aspects of the present disclosure.

[0014] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. DETAILED DESCRIPTION

[0015] Developments in medical science and electronic devices have led to developments in devices to sense, record, and interpret a person's biological indications or signals (e.g., temperature, nerve signals, brain waves, etc.). Biological signals (e.g., from a person), especially sensed nerve signals, are typically at a very low voltage (e.g., 10 μν to 100 μ\/). Very low voltage signals such as biological signals can be difficult to transmit over even short distances, due to interference (e.g., "noise") that can be induced in the conductors transmitting the very low voltage signals by external factors (e.g., radio waves and other signals). One current technique to transmit very low voltage signals is to place an amplifier and analog-to-digital converter (ADC) in close proximity to the source of the signal, to amplify and digitize the signal for transmission to other components.

[0016] As illustrated in Figure 1 , amplifiers and ADCs can be placed in close proximity to the sensors detecting biological signals, allowing the signals to be amplified, digitized, and transferred over longer distances to processors to interpret and record the signals.

[0017] In the case of sensors attached to wearable (e.g., to be worn by a person) conformal devices (e.g., flat, flexible devices suited to conform to the flesh of a person), amplifiers and ADCs can be made from thin film transistors (TFTs) or other integrated circuit devices and integrated into the body of the device. By forming the amplifiers and ADCs in this manner, the amplifiers and ADCs can be in close proximity to the sensors, while still allowing the sensors to be attached to the conformal devices. Such amplifiers and ADCs (e.g., integrated circuit and TFT amplifiers and ADCs) increase both the expense and the complexity of the sensing devices.

[0018] According to embodiments of the present disclosure, apparatuses and methods for conveying very low voltage signals (e.g., bioelectrical signals) through conformal conductors while mitigating interference to the signals are disclosed. An apparatus may include a first conductor to convey the signal, two second conductors parallel to the first conductor, an amplifier that amplifies the signal at unity voltage gain and supplies the amplified signal to the two second conductors, and two third conductors maintained at ground voltage potential that are parallel to the first and second conductors. A set of conductors involving first, second, and third conductors as described may be referred to as a triaxial conductor.

[0019] According to embodiments of the present disclosure, a method for conveying very low voltage signals while mitigating interference to the signals may include receiving the low voltage signals from a first conductor, amplifying the low voltage signals at unity voltage gain, supplying the amplified signals to two second conductors parallel to the first conductor with the first conductor between the second conductors, and maintaining two third conductors at ground voltage potential, with the third conductors parallel to the first conductors and second conductors, and the first conductor and second conductors between the third conductors.

[0020] Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all embodiments are shown. Indeed, the concepts may be embodied in many different forms and should not be construed as limiting herein. Whenever possible, like reference numbers will be used to refer to like components or parts.

[0021 ] Figure 2 schematically illustrates an exemplary system 200 in which aspects of the present disclosure may be practiced to convey low voltage signals from sensors to controller/processors. The system 200 utilizes triaxial conductors 202 to transmit low voltage signals, according to aspects of the present disclosure. Aspects of Figure 2 that are similar to Figure 1 have been described above with reference to Figure 1 . In system 200, sensors 104 detect signals and/or indications, and generate signals on triaxial conductors 202. The triaxial conductors convey the signals to the controller/processor 102, while mitigating interference (e.g., caused by radio waves or electromagnetic fields of other devices) to the signals. The triaxial conductors are described in more detail below, with reference to Figure 3.

[0022] The controller/processor 102 receives the signals from the triaxial conductor and may perform processing on the signals. The controller/processor may transmit (e.g., via Bluetooth® or other wireless communication protocols) the signals or information regarding the signals to other devices by means of the antenna 204. Alternatively or additionally, the controller/processor may control the operation of a separate transmitter or transceiver (not shown) that may transmit the signals to other devices by means of the antenna 204. While the antenna 204 is shown as a separate component, the disclosure is not so limited, and radio signals may be transmitted and/or received by means of an antenna that is integral with the transmitter or transceiver, or by means of an antenna that is integrated with the body of the system 200.

[0023] The controller/processor 102, sensors 104, and other components of the system 200 may receive electric power from a battery 106 or other power source. Additionally or alternatively, the system 200 may include a photovoltaic cell 1 10 (e.g., an organic photovoltaic (OPV) cell) that may charge the battery as illustrated or directly power the controller/processor, sensors, and other components of the system 200.

[0024] Figure 3 schematically illustrates an exemplary triaxial conductor 202 for conducting very low voltage signals, according to aspects of the present disclosure. The exemplary triaxial conductor 202 may be used as a component in the system 200, illustrated above with reference to Figure 2. The exemplary triaxial conductor 202 includes a first or central conductor 302 that receives a very low voltage signal (e.g., a bioelectric signal) from a source (e.g., a sensor 104). The first conductor may be, for example, formed from conductive material (e.g., copper or gold) on a flexible printed circuit board or other flexible substrate. The thickness 352 of the first conductor may be approximately 5 μιη to 100 μιη, for example, approximately 5 μιη to 50 μιη or, for example, approximately 10 μιη to 20 μιη.

[0025] The triaxial conductor 202 includes two second conductors 304a and 304b. The second conductors 304 are parallel to the first conductor 302, with the first conductor between the two second conductors. The two second conductors are connected with the controller/processor 102, which amplifies at unity voltage gain the signal received from the first conductor 302 and supplies the amplified signal to the two second conductors. The two second conductors are thus driven to a voltage equal to the voltage on the first conductor. Driving the two second conductors to a voltage equal to the voltage on the first conductor may inhibit electrostatic leakage to or from the first conductor. The second conductors may be, for example, formed from conductive material (e.g., copper or gold) on a flexible printed circuit board or other flexible substrate. The thicknesses 354a, 354b of the second conductors may each be approximately 5 μιη to 100 μιη, for example, approximately 5 μιη to 50 μιη or, for example, approximately 10 μιη to 20 μιη.

[0026] The triaxial conductor 202 also includes two first insulating layers 310a and 310b, each first insulating layer between the first conductor and one of the second conductors. The first insulating layers prevent the first conductor and second conductors from contacting each other, and may prevent the very low voltage signal on the first conductor from being conducted onto the second conductors. The first insulating layers may be formed from a plastic, or any suitable insulating (e.g., non-conductive) material. The thicknesses 360a, 360b of the first insulating layers may each be approximately 5 μιη to 100 μιη, for example, approximately 5 μιη to 50 μιη or, for example, approximately 10 μιη to 20 μιη.

[0027] The triaxial conductor 202 further includes two third conductors 306a and 306b. The third conductors 306a, 306b are parallel to the first conductor 302 and the second conductors 304a, 304b, with the first conductor and second conductors between the two third conductors. The two third conductors are connected to a ground of the device, such that the two third conductors are maintained at ground voltage potential. Driving the two third conductors to ground voltage may inhibit electrostatic leakage from outside the triaxial conductor from reaching the first conductor and second conductors. Similar to the first and second conductors, the third conductors may be formed from conductive material on a flexible printed circuit board or other flexible substrate. The third conductors may be thicker than the first and second conductors. For example, the thicknesses 356a, 356b of the third conductors may each be approximately 5 μιη to 200 μιη, for example, approximately 10 μιη to 150 μιη, or, for example, approximately 20 μιη to 100 μιη.

[0028] The triaxial conductor 202 also includes two second insulating layers 312a and 312b. Each of the two second insulating layers 312a, 312b is between a third conductor 306a, 306b and a second conductor 304a, 304b. The second insulating layers prevent the second conductors and third conductors from contacting each other, and may prevent the amplified signal on the second conductors from being conducted onto the third conductors. The second insulating layers may be formed from a plastic, or any suitable insulating (e.g., non-conductive) material. The second insulating layers may be thicker than the first insulating layers. For example, the thicknesses 362a, 362b of the second insulating layers may each be approximately 5 μιη to 200 μιη, for example, approximately 10 μιη to 150 μιη, or, for example, approximately 20 μιη to 100 μιη.

[0029] Figure 4 illustrates exemplary operations 400 for conveying an electric signal, according to aspects of the present disclosure. Operations 400 may be performed by a processor, for example. Operations 400 begin at 402 by receiving the electric signal from a first conductor of a printed circuit board. Operations 400 continue at 404 by amplifying the electric signal at unity voltage gain. At 406, the operations 400 continue by supplying the amplified electric signal to two second conductors disposed on the printed circuit board parallel to the first conductor with the first conductor between the two second conductors. Operations 400 continue at 408 by maintaining two third conductors at ground voltage potential, wherein the two third conductors are disposed on the printed circuit board parallel to the first conductor and second conductors with the first conductor and second conductors between the two third conductors.

[0030] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0031] Many modifications and other embodiments not set forth herein will come to mind to one skilled in the art to which the embodiments pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the description and claims are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. It is intended that the embodiments cover the modifications and variations of the embodiments provided they come within the scope of the appended claims and their equivalents. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0032] It is understood that the specific order or hierarchy of steps in the processes disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged. Further, some steps may be combined or omitted. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

[0033] Moreover, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." That is, unless specified otherwise or clear from the context, the phrase, for example, "X employs A or B" is intended to mean any of the natural inclusive permutations. That is, for example the phrase "X employs A or B" is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B. In addition, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from the context to be directed to a singular form. A phrase referring to "at least one of a list of items refers to any combination of those items, including single members. As an example, "at least one of: a, b, or c" is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

[0034] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:

1 . An apparatus for conveying an electric signal, comprising:

a first conductor disposed on a printed circuit board;

two second conductors disposed parallel to the first conductor on different layers of the printed circuit board, wherein the first conductor is between the two second conductors;

an amplifier configured to amplify an electric signal on the first conductor at unity voltage gain and supply the amplified signal to the two second conductors; and two third conductors maintained at ground voltage potential, wherein the two third conductors are disposed on the printed circuit board parallel to the first conductor and the two second conductors with the first conductor and second conductors between the two third conductors.

2. The apparatus of claim 1 , wherein each of the first conductor, second conductors, and third conductors is on a separate layer of the printed circuit board, and further comprising:

a plurality of first insulating layers, each first insulating layer disposed between the first conductor and one of the second conductors; and

a plurality of second insulating layers, each second insulating layer disposed between a second conductor and one of the third conductors.

3. The apparatus of claim 2, further comprising:

an antenna;

a radio transmitter; and

a processor connected with the first conductor and configured to:

convert the electric signal to a digital signal; and

transmit the digital signal via the radio transmitter and the antenna.

4. The apparatus of claim 2, wherein the first conductor, second conductors, and third conductors comprise copper.

5. The apparatus of claim 2, wherein:

the first conductor is between five micrometers and fifty micrometers thick; each of the second conductors is between five micrometers and fifty micrometers thick; and

each of the third conductors is between five micrometers and 100 micrometers thick.

6. An apparatus for conveying a bioelectrical signal, comprising:

a first conductor disposed on a printed circuit board and connected to a source of the bioelectrical signal;

an amplifier configured to amplify the bioelectrical signal at unity voltage gain and supply the amplified bioelectrical signal to the two second conductors; and

two third conductors maintained at ground voltage potential, wherein the two third conductors are disposed on the printed circuit board parallel to the first conductor and the two second conductors with the first conductor and second conductors between the two third conductors.

7. The apparatus of claim 6, wherein each of the first conductor, second conductors, and third conductors is on a separate layer of the printed circuit board, and further comprising:

8. The apparatus of claim 6, further comprising:

an antenna;

a radio transmitter; and

a processor connected with the first conductor and configured to:

convert the bioelectrical signal to a digital signal; and

transmit the digital signal via the radio transmitter and the antenna.

9. The apparatus of claim 8, wherein:

the first conductor is between five micrometers and 100 micrometers wide; each of the second conductors is between five micrometers and 100 micrometers wide; and

each of the third conductors is between five micrometers and 100 micrometers wide.

10. The apparatus of claim 9, wherein:

1 1 . The apparatus of claim 6, wherein:

the first conductor is between five micrometers and 100 micrometers wide; each of the second conductors is between five micrometers and 100 micrometers wide;

12. The apparatus of claim 6, wherein the first conductor, second conductors, and third conductors comprise copper.

13. The apparatus of claim 6, wherein:

14. The apparatus of claim 13, wherein each of the third conductors is thicker than the first conductor and each of the second conductors.

15. A method for conveying an electric signal, comprising:

receiving the electric signal from a first conductor of a printed circuit board; amplifying the electric signal at unity voltage gain;

supplying the amplified electric signal to two second conductors disposed on the printed circuit board parallel to the first conductor with the first conductor between the two second conductors; and

maintaining two third conductors at ground voltage potential, wherein the two third conductors are disposed on the printed circuit board parallel to the first conductor and second conductors with the first conductor and second conductors between the two third conductors.