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:
May. 20, 1986
Filed:
Aug. 16, 1984
Hendrikus C Ligtenberg, Nietap, NL;
Albertus Veld, Roden, NL;
Cordis Europa N.V., Roden, NL;
Abstract
The apparatus (14) is constructed and arranged to measure ions in a liquid (30) and comprises a measuring circuit (10) including an ISFET (16), a reference electrode (32), an amplifier (22) and a protection system (12)/guard circuit (40) connected to the measuring circuit (10). The protection system 12/guard circuit 40 comprises at least one electrode (46 or 47) connected via a low-impedance contact (or ring 62/46 or ring electrode 42) to the liquid (30) and coupled to the ISFET (16) by a protective element (64; 65, 66; or 68 and/or 50; 51, 52; 54; 56; or 58) having a low-impedance for high voltages and a high resistance to low voltages. In one preferred embodiment, the ISFET (16) is provided on a chip (90) and has an electrode (46/62) in as closely spaced relationship as possible to the gate region (34) of the ISFET (16).
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile