A widespread clinical diagnostic technique is to measure electrical current through skin attached electrodes. The measured currents are processed for non-invasive biophysical tracking of vital organ activity—the skin-detected electrical activity correlates with the biophysical activity of the vital organ (e.g., heart rate). Some examples of such skin electrode based clinical tracking include electro-cardiogram (ECG) and electro-encephalogram (EEG). The popular skin electrodes are wet electrodes, which use electrogel to enhance the electrical impedance between the electrode and the skin.
Wet electrodes, however, have several disadvantages. Wet electrodes require a long implementation time—having the preparation steps of injecting the electrogel with syringe and spreading the electrogel for each wet electrode (a typical clinical diagnostic technique may use 32 to 256 wet electrodes). Furthermore, electrogel is prone to drying, thereby making the wet electrodes unsuitable for long-term applications and/or experiments. To mitigate these disadvantages, dry electrodes have been developed. For example,
As such, a significant improvement on the electrode technology, particularly dry electrode technology is therefore desired.
Embodiments disclosed herein may solve the aforementioned technical problems and may provide other solutions as well. An example electrode may be formed by grouping together a plurality of hair electrodes (also referred to as bristle electrodes). Each of the hair electrodes may include a non-conductive hair electrode base that may provide the structural integrity and mechanical properties of the hair electrode. The hair electrode base may be formed by sculpting a substrate, e.g., laser cutting a polymer into hair structures. A conductive layer may be provided around the hair electrode base. The conductive layer may be formed by sputtering a metal (e.g., gold) on the hair electrode base.
In an embodiment, a flexible electrode for a clinical equipment and configured to detect electrical signals from a live tissue may be provided. The flexible electrode may comprise a plurality of hair electrodes, wherein each of the hair electrodes comprises: a non-conductive and flexible hair electrode base defining the structure of the hair electrode; and a gold outer layer covering the electrode base, the gold outer layer forming a conductive portion of the hair electrode and configured to detect the electrical signals from the live tissue.
In another embodiment, a flexible electrode configured for a clinical equipment and configured to detect electrical signals from a live tissue may be provided. The flexible electrode may comprise a plurality of hair electrodes, wherein each of the hair electrodes comprises: a non-conductive and flexible hair electrode base defining the structure of the hair electrode; and a conductive polymer outer layer covering the electrode base, the conductive polymer outer layer forming a conductive portion of the hair electrode and configured to detect the electrical signals from the live tissue.
In yet another embodiment, a method of manufacturing a flexible electrode for a clinical equipment and configured to detect electrical signals from a live tissue may be provided. The flexible electrode may comprise a plurality of hair electrodes. The method may comprise fabricating a plurality of non-conductive hair electrode bases for the plurality of hair electrodes; sputtering a metal on the plurality of hair electrode bases to form the conductive portions of the plurality of hair electrodes; and rolling the plurality of hair electrode bases with the sputtered metal to form the flexible electrode.
The figures are for purposes of illustrating example embodiments, but it is understood that the present disclosure is not limited to the arrangements and instrumentality shown in the drawings. In the figures, identical reference numbers identify at least generally similar elements.
Embodiments disclosed herein provide 3-dimensional dry electrodes formed by a plurality of 2-dimensional hair electrodes. Each of the hair electrodes may be formed by non-conductive hair electrode base and a conductive layer. The non-conductive hair electrode base may be formed of substances such as a polymer using techniques such as laser cutting. A conductive layer may be applied to the hair electrode bases using technique such as metal sputtering to generate the plurality of 2-dimensional hair electrodes. The plurality of 2-dimensional hair electrodes may then be grouped together (e.g., rolled) to form a 3-dimensional dry electrode.
It should be noted that the term “2-dimensional” is used to describe a generally flat structure, which of course exists in the three dimensional world with length, width, and depth, but because it is generally flat, the depth is much less than the length and width, and is referred to in this description as “2-dimensional” when in fact it is three dimensional, but only to describe it in contrast to a rolled up example, where a long, flat sheet of electrode bristles is rolled up as described herein, thereby making the overall dimensions of the rolled up system a more three dimensional look, although of course, they all exist in the three dimensional real world.
At step 202 an electrode base 210 for the 2-dimensional hair electrode may be formed. The hair electrode base 210 may be the non-conducting part of the 2-dimensional hair electrode and may provide structural integrity and determine the overall shape of the 2-dimensional hair electrode (e.g., circular cross section, rectangular cross section). The hair electrode base 210 may also largely govern the mechanical properties of the 2-dimensional hair electrode. The mechanical properties may include stress and strain, which may determine the flexibility of the 2-dimensional hair electrode when pressed against the skin.
Hair electrode base 210 base may be formed of any type of material such as polymer, cellulose, chitin, chitosan, synthetic flexible fiber, microfiber, nanotube, parylene, elastomer, thermal elastomer, liquid crystal elastomer, Polysacharides, and/or natural fabrics, or any combination of any of the above in any permutation. It should be understood that these materials are just some examples and other substances forming the hair electrode base 210 should also be considered within the scope of this disclosure.
Using a substrate, e.g., one formed from one or more of the aforementioned materials, the hair electrode base 210 may be formed. For example, electromagnetic radiation such as a laser 208 may be used to generate, sculpt, and/or shape the hair electrode base 210 out of the substrate. As an example, the laser 208 may sculpt or shape a plastic material such as a polyimide into a hair structure, which may then form the hair electrode base 210. The laser 208 is just but an example, and other types of technology may be used to generate and/or shape the hair electrode base 210. For instance, liquid cutting mechanisms such as a water jet cutting may be used. Alternatively or additionally, solid cutting mechanisms such as diamond cutting may be used. The hair electrode base 210 may also be generated through molding, such as injection molding. Another technology to generate the hair electrode base may be 3D printing. Therefore, any type of technology forming a strand like structure, which may then form the hair electrode base 210 should be considered within the scope of this disclosure. The hair electrode base 210 may be formed as a pillar structure (e.g., having a non-hollow cross section) or a tube (e.g., having a hollow cross section), or rectangular structure.
At steps 204 and 206, the hair electrode base 210 may be coated with a first conductive material layer 212 and a second conductive material layer 214 to generate the 2-dimensional hair electrode 216. In some embodiments, the steps 204 and 206 may be sequential: the hair electrode base 210 may be coated with a first conductive material layer 212 on one side and then coated with a second conductive material layer 214 on the other side. In other embodiments, the steps 204 and 206 may not be sequential in that the hair electrode base 210 may be coated both conductive material layers 212 and 214 at the same time. It should be understood, however, that
Any type of technology may be used for the adding the conductive material layers 212 and 214 onto the hair electrode base 210. For example, for conductive materials 212 and 214 may be formed by a metal (e.g., gold), the metal may be sputtered to the hair electrode base 210. Alternatively or additionally, the metal may be thermally and/or electrochemically deposited onto the hair electrode base 210. In some embodiments, the metal may be into a paste, and the hair electrode base 210 may be dipped into the paste to receive the metal coating. In some embodiments, the conductive material layers 212 and 214 may be formed by metal nanotubes or metal nanoparticles. The metal may also be formed into the powder, and the powder may be pressed into the hair electrode base 210.
In some embodiments, the conductive material layers 212 and 214 may be formed by conductive polymers. The conductive polymers may be electrochemically deposited to the hair electrode base 210. Alternatively or additionally, the conductive polymers may be formed into a paste, and the hair electrode base 210 may be dipped into the paste thereby receiving the coatings as the conductive layers 212 and 214. The conductive polymers may also be added as nanotubes and nanoparticles onto the hair electrode base 210 to form the conductive material layers 212 and 214. Other non-limiting examples include but are not limited to spin-coating, dipping, laminating (roll-to-roll), brush coating, and spray coating, alone or in any combination.
The electrode with the conductive and non-conductive portions thus formed may be referred to as a 2-dimensional hair electrode 216, as described above. The 2-dimensional hair electrode 216 may also be referred to as a 2-dimensional bristle electrode. The 2-dimensional hair electrode 216 (or 2-dimensional bristle electrode 216) may have any shape, including but not limited to spherical, conical, cubical, or rectangular. The tip of the 2-dimensional hair electrode 216 may be of any shape such as spherical, conical, cubical, triangle, jagged surface, or rectangular.
In some embodiments, a plurality of 2-dimensional hair electrodes 216 may be grouped together to form a 3-dimensional electrode (several examples of 3-dimensional electrodes are described below). In some embodiments, the 2-dimensional hair electrodes 216 may be formed in batches, where a batch may be used to form a 3-dimensional electrode (e.g., by bunching a batch of the 2-dimensional electrodes), as described with reference to
At step 402, a batch of hair electrode bases 410 is formed. For instance, the hair electrode bases 410 may be formed of a synthetic material such as a polymer. As shown, a sheet of the synthetic material may be subjected to a shaping mechanism (e.g., a laser cutting) to cut the lower portion of the synthetic material into several strands. Each strand may form a 2-dimensional hair electrode base 410 (such a 2-dimensional hair electrode base 210 shown in
At step 404, the batch of hair electrode bases 410 may receive a coating of a conductive material. For example, a portion 420 of the synthetic sheet 422 without the hair electrode bases 410 may be taped (e.g., using a masking tape), and the untaped portion may receive the conductive coating, e.g., through metal sputtering. The sheet 422 may then be turned over and the portion on the other side of portion 420 may be taped, and the untaped portion may receive the conductive coating. Such double-sided coating may generate the batch of 2-dimensional hair electrodes 416, each with non-conductive inner material and conductive outside layer.
At step 406, the batch of 2-dimensional hair electrodes 416 may be rolled to form a 3-dimensional electrode 418. The 2-dimensional hair electrodes 416 within the 3-dimensional electrode 418 may be held together by a holder (described in detail with reference to
It should be understood that the aforementioned process 400 of generating the 3-dimensional electrode 418 is just an example, and other types of processes should also be considered within the scope of this disclosure. Another type of 3-dimensional electrode may be formed by rolling conductive films-the conductive films forming the individual flexible electrodes (e.g., as an alternative to the 2-dimensional hair electrodes). A 3-dimensional electrode may also be formed by a rolled electrode with a flexible substrate (e.g., not necessarily shaped into hair like structure). The rolled flexible substrate may then be coated with a conductive material. Alternatively, the 3-dimensional electrode may be formed by rolled flexible substrate electrodes already having a metal coating.
In some other non-limiting examples, the “2-dimensional” flat electrode bristles may be shaped in other ways including but not limited to circular, spherical, or other 3-dimensional structures or patterns.
As an alternative to rolling or any other type of batching, a 3-dimensional electrode may also be generated through injection molding. For instance, the 3-dimensional structure of the 3-dimensional electrode may directly be generated through one or more steps of injection molding. Alternatively, the 3-dimensional electrode may be generated through 3-dimensional printing, which may print different layers eventually forming the 3-dimensional electrode.
Using one or more of the above techniques, different types of 3-dimensional electrodes may be generated. Some examples of the 3-dimensional electrodes are described below.
Each of the 3-dimensional electrodes 602 may detect and measure electrical signals in the live tissue 606. The measured electrical signals may be transmitted to the electronic components through the corresponding communication links 608. The communication links 608 may include wired and/or wireless communication links. In some embodiments, the measured electrical signal may be amplified. The amplification may be within the electrodes 602, at one or more points in the communication links 608, and/or the electronic components 604. In some embodiments, the electrodes 602 may be passive electrodes, not necessarily providing amplification or other electronic functionality.
The electronic components 604 may further process and analyze the electrical signals detected by the 3-dimensional electrodes 602 and amplified at one or more points. For example, the electronic components 604 may include a digital processor that may convert the signal into a graphical output (e.g., a heartbeat pattern of an ECG). The electronic components 604 may further comprise a storage (e.g., hard disk, solid state drive) to store the measured electrical signals and/or patterns extracted therefrom. The electronic components 604 may further have communication components to communicate the measured electrical signals and/or patterns extracted therefrom to other external components (e.g., communicating to a remote computer through a network).
At step 802, a plurality of non-conductive hair electrode bases (to form the 2-dimensional hair electrodes) may be fabricated. The fabrication may be through any kind of mechanism. For instance, a non-conductive substrate (e.g., a polymer) may be laser sculpted to form the non-conductive hair bases.
At step 804, metal (e.g., gold) may be sputtered to the plurality of hair electrode bases. The metal may form a conductive portion of the 2-dimensional hair electrodes. It should be understood that sputtering the metal is just an example of adding a conductive portion of the 2-dimensional hair electrodes. Alternatives of adding the conductive portion include dipping the non-conductive hair electrode bases into a metal paste, thermally depositing the metal, electronically depositing the metal, etc. Furthermore, conductive polymers may be used instead of the metal.
At step 806, the plurality of hair electrode bases with the sputtered metal may be rolled to form the 3-dimensional electrode. The rolling is also just an example, and the 3-dimensional electrode may be formed through other techniques such as 3-dimensional printing, injection molding, etc.
The holder 900 is designed fit into existing EEG cap sockets, therefore alterations to the existing EEG cap sockets may not be required to accommodate the embodiments disclosed herein. As shown, the holder 900 may include a screw holder 902 and a fastening member 904. The screw holder 902 may have a hollow middle portion that may be used to pass a wire 908, which in turn may be attached to a 3-dimensional electrode 906.
At step 1002, the screw holder 902 may be inserted into a cap socket 1012 of an EEG cap 1006. The screw holder 902 may be inserted from the surface that interfaces the human head, i.e., the shown surface at step 1002 is the inside surface 1008 of the EEG cap 1006. The screw holder 902 may already have the wire 908 passing through its hollow interior, where the wire has a 3-dimensional electrode attached at the end (e.g., as shown in
At step 1004, the EEG cap 1006 may be flipped over to expose an outer surface 1010 (i.e., the surface not touching the human head). The fastening member 904 may be fastened to the screw holder 902, thereby tightening the holder 900 on the EEG cap 1006.
Additional examples of the presently described method and device embodiments are suggested according to the structures and techniques described herein. Other non-limiting examples may be configured to operate separately or can be combined in any permutation or combination with any one or more of the other examples provided above or throughout the present disclosure.
It will be appreciated by those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the disclosure is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.
It should be noted that the terms “including” and “comprising” should be interpreted as meaning “including, but not limited to”. If not already set forth explicitly in the claims, the term “a” should be interpreted as “at least one” and “the”, “said”, etc. should be interpreted as “the at least one”, “said at least one”, etc. Furthermore, it is the Applicant's intent that only claims that include the express language “means for” or “step for” be interpreted under 35 U.S.C. 112(f). Claims that do not expressly include the phrase “means for” or “step for” are not to be interpreted under 35 U.S.C. 112(f).
This application claim priority to U.S. Provisional Application No. 63/322,534, filed Mar. 22, 2022 and entitled “Flexible Dry Electrodes,” which has been incorporated in its entirety by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/US2023/064768 | 3/21/2023 | WO |
Number | Date | Country | |
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63322534 | Mar 2022 | US |