Solid state reference electrode

• US 4,450,842 A
• Filed: 11/06/1981
• Issued: 05/29/1984
• Est. Priority Date: 04/25/1980
• Status: Expired due to Term

• Current Assignee: El Paso Products Company (Huntsman Corporation)
• Original Assignee: Cordis Corporation (Cardinal Health, Inc.)
• Inventors: Saulson, Stanley H., Zick, Gregory L.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US06/318,693
• Time in Patent Office: 935 Days
• Field of Search: 128/635, 128/632, 128/639-641, 128/644, 204/195 B, 204/195 P, 204/403, 204/415, 204/431-433
• US Class Current: 600/357
• CPC Class Codes: G01N 27/301 Reference electrodes
• CPC Class Codes: G01N 33/4925 measuring blood gas content, e.g. O2, CO2 , HCO3

Abstract

In the reference electrode construction disclosed herein, silver and silver chloride particles are incorporated in a mixture including a fusible glass frit. After being printed on a suitable substrate, the mixture is fired to bond the silver/silver chloride composite into a conductive film on the surface of the substrate.

Claims

1. A solid state sensor for measuring the oxygen of blood by contact with a patient'"'"'s skin, said sensor comprising:

a thin ceramic substrate disc having front and back surfaces;

a noble metal cathode, extending through said substrate from the back surface to the front surface where, at a first limited area of said front surface, said cathode is exposed for reducing oxygen; and

a reference electrode comprising a mixture of silver, silver chloride and a fused glass frit forming a conductive film coating over a second limited area of said disc front surface.

2. The solid state sensor of claim 1 additionally comprising a heating element printed onto a first limited area of said back surface as a coating of resistor material.

3. The solid state sensor of claim 2 additionally comprising a thermistor printed onto a second limited area of said back surface.

4. The solid state sensor of claim 3 wherein said heating element and said thermistor are annular-shaped coatings on said back surface.

5. The solid state sensor of claim 1, 3 or 4 wherein said front surface is covered with an oxygen-permeable polymer coating.

6. The solid state sensor of claim 1, 3 or 4 wherein said reference electrode is an annular-shaped area of a film of said mixture.

7. The solid state sensor of claim 1, 3 or 4 wherein at least one of said silver and silver chloride are in the form of plate-like particles.