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1. WO1993016481 - CAPACITANCE HUMIDITY SENSOR

Publication Number WO/1993/016481
Publication Date 19.08.1993
International Application No. PCT/US1993/000956
International Filing Date 03.02.1993
Chapter 2 Demand Filed 01.09.1993
IPC
G01N 27/22 2006.01
GPHYSICS
01MEASURING; TESTING
NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
27Investigating or analysing materials by the use of electric, electro-chemical, or magnetic means
02by investigating impedance
22by investigating capacitance
CPC
G01N 27/225
GPHYSICS
01MEASURING; TESTING
NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
27Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
02by investigating impedance
22by investigating capacitance
223for determining moisture content, e.g. humidity
225by using hygroscopic materials
Y10T 29/435
YSECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
10TECHNICAL SUBJECTS COVERED BY FORMER USPC
TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
29Metal working
43Electric condenser making
435Solid dielectric type
Applicants
  • JOHNSON SERVICE COMPANY [US]/[US]
Inventors
  • THOMA, Paul, E.
Agents
  • COOPER, John, C., III
Priority Data
07/831,55305.02.1992US
Publication Language English (EN)
Filing Language English (EN)
Designated States
Title
(EN) CAPACITANCE HUMIDITY SENSOR
(FR) CAPTEUR CAPACITIF D'HUMIDITE
Abstract
(EN)
A capacitance humidity sensor (10) according to the invention has a film core (11) which is in contact with a pair of polymeric conductive layers (12, 13) bonded to opposite faces of the core (11). The core (11) is made of a polymeric material having a dielectric constant which varies substantially linearly with humidity, such as a polyimide or polyparabanic acid. The conductive layers (12, 13) are made of a polymeric material, at least a portion of which includes sulfur atoms in the backbone chain and having conductive particles, such as carbon particles, dispersed therein. Such conductive layers (12, 13) provide superior performance and corrosion resistance in comparison to the metal films employed in the prior art and in comparison to cellulosic polymers containing conductive particles.
(FR)
Capteur (10) capacitif d'humidité comportant une âme (11) sur les deux faces de laquelle sont collées des couches polymères conductrices (12, 13). L'âme (11) est constituée d'un matériau polymère, tel qu'un polyimide ou un acide parabanique, dont la constante diélectrique varie de manière linéaire en fonction de l'humidité. Les couches conductrices (12, 13) sont constituées d'un matériau polymère dont au moins une partie renferme des atomes de soufre dans la chaîne du squelette et des particules conductrices, telles que des particules de carbone, en dispersion. Ces couches conductrices (12, 13) assurent une qualité de fonctionnement et une résistance à la corrosion supérieures par rapport aux films métalliques employés antérieurement et aux polymères cellulosiques renfermant des particules conductrices.
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