US 5,387,329 A · Extended use planar sensors

Abstract

A planar, solid-state electrochemical oxygen sensor having a substrate, conductive strips deposited on the substrate, and a dielectric layer insulating portions of the conductive strips except those portions which define a working electrode and at least one second electrode. The working electrode may be defined by an open printed region of the dielectric, or by a needle-punched or laser-burned hole or opening in the dielectric which exposes a small region of one of the conductive strips. A solid electrolyte contacting the electrodes is covered by a semipermeable membrane which may comprise an acrylonitrile butadiene copolymer or an acrylate-based copolymer. A sample chamber is defined by the membrane, a cover member, and a gasket therebetween, and has a volume of from about 1 to about 2 .mu.l. The gasket is formulated from the highly cross-linked polymerization product of epichlorohydrin. All sensor components are selected such that a sensor operable for at least 2 days under normal conditions is produced.

Claims89

Dependent claims

A solid-state planar oxygen sensor comprising:

an electrically nonconductive substrate;
a first electrically conductive material adhered to a first portion of said substrate, at least a portion of said first conductive material being covered with an electrically insulating dielectric coating and at least one portion of said first conductive material remaining uncovered by said electrically insulating dielectric coating, said uncovered portion of said first conductive material defining a working electrode area;
a second electrically conductive material adhered to a portion of the substrate, a portion of said second conductive material being covered with the electrically insulating dielectric coating and at least one portion of said second conductive material remaining uncovered by said electrically insulating dielectric coating, said uncovered portion of said second conductive material defining a counter electrode area;
a hygroscopic solid electrolyte provided on at least the working electrode area and the counter electrode area, said electrolyte having a swell value of less than two times its dry volume when provided with water;
a semipermeable membrane covering said electrolyte having an oxygen permeability of less than 8 Barrers;
a cover member covering said semipermeable membrane and having a recess formed therein, said recess having a perimeter facing the membrane and at least one passageway connected to the recess;
and
a gasket contacting the recess perimeter and the membrane to form a seal therebetween, the gasket, cover member, and membrane defining a sample chamber.

5 more elements

A solid-state planar oxygen sensor comprising:

an electrically nonconductive substrate;
a first electrically conductive material adhered to a first portion of said substrate, at least one portion of said first conductive material being covered with an electrically insulating dielectric coating and at least one portion of said first conductive material remaining uncovered by said electrically insulating dielectric coating, said uncovered portion of said first conductive material defining a working electrode area;
a second electrically conductive material adhered to at least a second portion of the substrate, a portion of said second conductive material being covered with the electrically insulating dielectric coating and at least one portion of said second conductive material remaining uncovered by said electrically insulating dielectric coating, said uncovered portion of said second conductive material defining a counter electrode area;
an electrolyte provided on at least the working electrode area and the counter electrode area;
and
a polymeric semipermeable membrane covering the electrolyte, said membrane comprising the polymerization product of at least one monomer having the formula CH.sub.2 =C(R.sub.1)(COOR.sub.2), where R.sub.1 and R.sub.2 are each selected from the group consisting of hydrogen, hydrocarbon groups, and alcohol groups and R.sub.1 and R.sub.2 can be the same or different.

3 more elements

In an electrochemical oxygen sensor having a semipermeable membrane, electrochemical means on a first side of said membrane for detecting an analyte in a sample, and a sample chamber on a second side of said membrane for receiving said sample, said chamber defined in part by said second side of said membrane and a cover member having a recess formed therein, said recess having a perimeter facing said second side of said membrane, the improvement comprising:

a gasket for forming a liquid and gas impermeable seal between said second side of said semipermeable membrane and said cover member recess perimeter, said gasket having a Shore A hardness of from about 10 to about 100, an oxygen permeability of less than 20 Barrers, being liquid impermeable and formulated to be substantially free of mobile extractable materials which, when the gasket is used with an adjacent semipermeable membrane, would leach into said membrane affecting physical or permeability characteristics therein, formulated to be substantially free of mobile sulfides and battery metals, and being effective in forming and maintaining said seal for at least 2 days under normal sensor operation.

Dependencies are inferred from the claim text.

Extended use planar sensors

Life of this patent

Extended use planar sensors

Life of this patent

Abstract

Claims89