METHOD AND APPARATUS FOR SENSING BIOELECTRIC POTENTIALS

• US 3,568,662 A
• Filed: 07/07/1967
• Issued: 03/09/1971
• Est. Priority Date: 07/07/1967
• Status: Expired due to Term

• Current Assignee: Donald B. Everett, Louis W. Schlenz
• Original Assignee: Donald B. Everett, Louis W. Schlenz
• Inventors: Everett, Donald B., Schlenz, Louis W.
• Application Number:
  US04/651,737
• Time in Patent Office: 1,341 Days
• US Class Current: 600/384
• CPC Class Codes: A61B 5/302 for capacitive or ionised electrodes, e.g. metal-oxide-semiconductor field-effect transistors [MOSFET]

Abstract

A method and apparatus for sensing bioelectric potentials utilizing a passive, capacitive coupling to the body and establishment by such capacitive coupling of an electrical signal representative of the body potential at the site of such capacitive coupling. The capacitive coupling includes an electrode member and a solid dielectric between the member and a body. In one example, a semiconductor device can serve the function of electrode member and its dielectric and include provision for changing the bias of the device to change the thickness of the dielectric or the effective area of the electrode member. A pair of passive capacitive electrode couplings to the body are provided with the respective outputs connected to a differential amplifier. The electrode can be formed in the configuration of a needle for measuring intercellular potentials.

Claims

1. Apparatus for detecting bioelectric potentials comprising at least one electrode means for providing a substantially electrically nonconducting region of solid dielectric material between said electrode and a body, said electrode and solid dielectric region comprising a unitary member, and means electrically connected to said electrode for producing a signal representative of the potential electrostatically induced on said electrode in variable accordance with body potentials originating within the body.

2. The aPparatus in accordance with claim 1 including a pair of such electrodes and associated nonconducting regions and wherein said signal-producing means includes a differential amplifier.

3. The apparatus in accordance with claim 1 including means for changing the electrical relationship of said electrode and the associated nonconducting region to change the electrical capacitive coupling of said electrode member with respect to the body.

4. The apparatus in accordance with claim 3 wherein said capacitive coupling changing means includes means for changing the effective thickness of said electrically nonconducting region.

5. The apparatus in accordance with claim 3 wherein said capacitive coupling changing means includes means for changing the effective area of said electrode.

6. The apparatus in accordance with claim 5 wherein said electrode is formed of a semiconductive material including regions of opposite type and wherein said capacitive coupling changing means includes means for applying a signal between regions of said semiconductive material for changing the effective area of one of said regions having a surface portion adjacent to said nonconducting region.

7. The apparatus in accordance with claim 1 including means for changing the effective capacitance of said electrode and said nonconducting region relative to the body.

8. Apparatus for detecting bioelectric potentials originating internally within a body or biological tissue comprising a pair of electrode members, means for providing a substantially electrically nonconducting region between each of said electrode members and a body with said electrode members passively capacitively coupled to the body, said means comprising a solid dielectric, a differential amplifier, means electrically connecting said electrode members to said differential amplifier and a readout means connected to said differential amplifier for producing a waveform representative of the internally generated body potentials.

9. The apparatus in accordance with claim 8 including means for changing the effective capacitive coupling of said electrode members and nonconducting region providing means to said body.

10. The apparatus in accordance with claim 9 wherein said capacitive coupling changing means includes means for changing the thickness of said electrically nonconducting region.

11. The apparatus of claim 9 wherein said capacitive coupling changing means includes means for changing the effective area of said electrode members adjacent said nonconducting regions.

12. The method of measuring bioelectric potentials comprising the steps of passively capacitively coupling to a body at least at one location thereon, by means including a solid dielectric, and electrostatically deriving an electrical signal representative of the internally generated body potential originating within the body at said location.

13. The method of measuring bioelectric potentials comprising the steps of:

passively capacitively coupling to a body at least at two spaced-apart locations by means including a solid dielectric, establishing electric potentials representative of the internally generated body potentials at said locations, and combining said representative potentials to produce an output signal representative of internally generated body potentials between said spaced apart locations.

14. The method in accordance with claim 13 wherein the comparison of the established body potentials includes the step of causing electrons to flow toward and away from the capacitive coupling without affecting the body potential at the site, thereby allowing measurement of body potentials down to and including DC.

15. The method in accordance with claim 14 wherein said step of causing electrons to flow includes the step of varying the capacitive coupling.