JPS6478148A - Oxygen sensor - Google Patents

Abstract

PURPOSE:To obtain an oxygen sensor which is simple and small in size, and whose power consumption is low by constituting a single element so as to confine an electrochemical oxygen pump function with an in-pore diffusion controlled speed function. CONSTITUTION:In about the center part of a substrate 5 consisting of a zirconia solid-state electrolyte, a diffusion hole 6 is formed. On the reverse side and the surface of the substrate 5, a porous internal electrode (cathode) 7a and a porous external electrode (anode) 7b are formed. At the time of oxygen pumping, the substrate 5 functions as a conductive medium of an oxygen ion, and also, the diffusion hole 6 functions so as to an in-pore diffusion controlled speed to oxygen replenished by diffusion to an internal chamber 10 from gas to be measured. Hermetically sealing members such as a sealing plate 8 and a sealing spacer 9, etc., are constituted by sealing hermetically an electrode 7a, and an atmosphere in the internal chamber 10 can be isolated from an atmosphere to be measured. Also, since oxygen is brought to diffusion controlled speed by the diffusion hole 6, a threshold current flowing to a current measuring circuit 12 is proportional to oxygen concentration of gas to be measured, therefore, by measuring this current, desired oxygen concentration can be detected.