The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 09, 1979
Filed:
Sep. 27, 1977
Martin A Afromowitz, Seattle, WA (US);
Sinclair S Yee, Seattle, WA (US);
The Board of Regents of the University of Washington, Seattle, WA (US);
Abstract
An improved ion-sensitive electrode is described, particularly in terms of the structure of a pH electrode and first and second processes for making the same. The pH electrode includes a substrate, preferably of forsterite, which is configured as a wafer having a substantially planar wafer surface. A continuous conducting layer, formed by either thin-film vapor deposition or thick-film screening processes, is formed on the substantially planar wafer surface in a desired configuration. A first region of the continuous conducting layer, and contiguous portions of the substantially planar wafer surface, are covered by a continuous membrane layer preferably composed of a pH-sensitive glass such as Corning Code 0150 glass. Typically, the membrane layer is formed by a thick-film process which involves the reduction of the glass to a fine powder, the mixing of the powder with an organic vehicle including an organic solvent and an organic binder to form a glass paste, and the application of the glass paste to the wafer through a wire mesh screen having an open region therethrough corresponding in configuration to that of the desired membrane layer. The paste when applied to the wafer is fused into a continuous membrane layer by the application of heat, at a first temperature to drive off the organic solvent and at a second temperature or temperatures to drive off the organic binder and to fuse the glass. An insulated output lead is connected directly to a second region of the conducting layer. Alternatively, an active device chip, such as that including a field effect transistor, is bonded to the wafer and interconnected with the second region of the conducting layer and with the output lead or leads. The exposed conducting elements of the electrode, including the second region of the conducting layer, the active device chip, and all exposed portions of the leads, are covered by a fluid-tight seal. Other ion-sensitive electrodes and variations of the aforementioned processes are described.