Method of producing a miniature internal reference gas chamber within an automotive, internal reference, solid electrolyte, lean oxygen sensor

Claim 1

A method of producing an internal reference gas chamber in a thin film, internal reference, solid electrolyte oxygen sensor having laterally disposed galvanic sense and pump cells comprising the steps of: (a) providing a non-ionically conductive substrate; (b) depositing a first this film layer of material onto a planar surface of said substrate within the oxygen sensor, said material comprising not less than two distinct components, a sacrificial component and a porous component, to a thickness of not less that about 0.1 micron and not greater than about 20.0 microns; (c) patterning said thin film layer of material to form at least two distinct patterned configurations, the first patterned configuration of said material contacts an electrode comprised within the galvanic sense cell and an electrode comprised within the galvanic pump cell, the second patterned configuration of said material delineates a serpentine, tortuous channel connecting the first patterned configuration of said material to an external orifice; (d) depositing a second thin film layer of material onto said patterned first layer of material so that said patterned first layer of material is enveloped everywhere except at said external orifice; and (e) subsequently selectively removing said sacrificial component of said material via said serpentine, tortuous channel and said external orifice by thermal or chemical decomposition, so that at least one component, the porous component, of said material remains; effective to produce a miniaturized internal reference gas chamber provided by the porosity of a porous material for use in a rapid response, highly precise oxygen partial pressure detector for detecting air/fuel ratios for internal combustion engines operating with lean air/fuel mixtures.

Claim 2

A method of producing an internal reference gas chamber in a thin film, internal reference, solid electrolyte oxygen sensor having laterally disposed galvanic sense and pump cells comprising the steps of: (a) providing a non-ionically conductive substrate; (b) depositing a first this film layer of material onto a planar surface of said substrate within the oxygen sensor, said material comprising not less than two distinct components, a sacrificial component and a porous component, to a thickness of not less that about 0.1 micron and not greater than about 20.0 microns; (c) patterning said thin film layer of material to form at least two distinct patterned configurations, the first patterned configuration of said material contacts an electrode comprised within the galvanic sense cell and an electrode comprised within the galvanic pump cell, the second patterned configuration of said material delineates a serpentine, tortuous channel connecting the first patterned configuration of said material to an external orifice; (d) depositing a second thin film layer of material onto said patterned first layer of material so that said patterned first layer of material is enveloped everywhere except at said external orifice; and (e) subsequently selectively removing said sacrificial component of said material via said serpentine, tortuous channel and said external orifice by thermal or chemical decomposition, so that at least one component, the porous component, of said material remains; effective to produce a miniaturized internal reference gas chamber provided by the porosity of a porous material for use in a rapid response, highly precise oxygen partial pressure detector for detecting air/fuel ratios for internal combustion engines operating with lean air/fuel mixtures.