Humidity-sensitive element
First Claim
1. A humidity-sensitive element comprising an insulating substrate, a pair of electrodesformed thereon apart from each other by a definite distance, and a coating of humidity-sensitive organic material formed to cover said electrodes, said coating of humidity-sensitive organic material being a synthetic polymer having both a hydrophobic moiety and another moiety selected from the group consisting of an ionic moiety and a hydrophilic moiety, to give the material a property to change its electric resistance depending upon the moisture content in the atmosphere, characterized in that said coating is formed by applying a latex comprising the synthetic polymer to said electrodes, the particles forming said latex having the hydrophobic moiety forming a core of each latex particle and the another moiety forming a surface layer on the core of each latex particle, the material being an aggregate of said particles, with the particles adhering to each other to form a continuous film for the coating.
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Abstract
The humidity-sensitive element of this invention is composed of an insulating substrate (1), a pair of electrodes (2, 3) mounted thereon, and a humidity-sensitive material (8) covering the electrodes. The humidity-sensitive material (8) has a property to change its electric resistance depending on the moisture content in the atmosphere and is formed from fine particles each having a hydrophobic core and a hydrophilic group-containing surface layer covering the core. This humidity-sensitive element exhibits a nearly linear relationship between logarithum of electric resistance and relative humidity and small hysteresis, permitting a precise measurement of relative humidity. Insulating substrate (1) and electrodes (2,3) are preferred to form from an insulating layer of silicon semiconductor and conductive monosilicon formed on it, respectively. This permits size reduction of humidity-sensitive elements or devices.
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Citations
33 Claims
- 1. A humidity-sensitive element comprising an insulating substrate, a pair of electrodesformed thereon apart from each other by a definite distance, and a coating of humidity-sensitive organic material formed to cover said electrodes, said coating of humidity-sensitive organic material being a synthetic polymer having both a hydrophobic moiety and another moiety selected from the group consisting of an ionic moiety and a hydrophilic moiety, to give the material a property to change its electric resistance depending upon the moisture content in the atmosphere, characterized in that said coating is formed by applying a latex comprising the synthetic polymer to said electrodes, the particles forming said latex having the hydrophobic moiety forming a core of each latex particle and the another moiety forming a surface layer on the core of each latex particle, the material being an aggregate of said particles, with the particles adhering to each other to form a continuous film for the coating.
- 15. A humidity-sensitive material, characterized by comprising a plurality of fine particles, each particle having a hydrophobic core and a surface layer formed from a compound selected from the group consisting of an ionic group compound and hydrophilic group compound enclosing said core, said material being an aggregate of said plurality of fine particles, whereby, because of the low moisture absorption of the cores, expansion or shrinkage of a film formed of said material is prevented.
- 24. A humidity-sensitive element comprising an insulating substrate, said insulating substrate comprising a silicon semiconductor substrate and an electric insulating layer formed thereon, a pair of electrodes formed thereon apart from each other by a definite distance, and a coating of humidity-sensitive material formed to cover said electrodes, said coating of humidity-sensitive material having a property to change its electric resistance depending upon the moisture content in the atmosphere, characterized in that said coating is formed from fine particles each having a hydrophobic core and a surface layer formed from a compound selected from the group consisting of an ionic group compound and a hydrophilic group compound covering said core.
- 26. The humidity-sensitive element comprising an insulating substrate, said insulating substrate comprising a first electric insulating layer formed of silicon dioxide on a silicon semiconductor substrate and a second electric insulating layer formed of silicon nitride on the first electric insulating layer, a pair of electrodes formed thereon apart from each other by a definite distance, said pair of electrodes being a pair of conductive polysilicon electrodes formed on the second electric insulating layer to oppose each other with a narrow space therebetween, said conductive polysilicon electrodes being formed by implanting phosphorous ions or boron ions into the polysilicon, and a coating of humidity-sensitive material formed to cover said electrodes, said coating of humidity-sensitive material having a property to change its electric resistance depending upon the moisture content in the atmosphere, characterized in that said coating is formed from fine particles each having a hydrophobic core and a surface layer formed from a compound selected from the group consisting of an ionic group compound and a hydrophilic group compound covering said core.
- 28. The humidity-sensitive element comprising an insulating substrate, a pair of electrodes formed thereon apart from each other by a definite distance, and a coating of humidity-sensitive material formed to cover said electrodes, said coating of humidity-sensitive material having a property to change its electric resistance depending upon the moisture content in the atmosphere, characterized in that said coating is formed from fine particles each having a core of a hydrophobic material and a surface layer of a material having a moiety selected from the group consisting of an ionic moiety and a hydrophilic moiety covering said core, where, because of the low moisture absorption of the cores, expansion or shrinkage and consequent peeling of the coating off the substrate is prevented.
- 30. A humidity-sensitive element comprising an insulating substrate including a silicon semiconductor substrate and an electric insulating layer formed thereon, a pair of electrodes formed thereon apart from each other by a definite distance, and a coating of humidity-sensitive organic material formed to cover said electrodes, said coating of humidity-sensitive organic material being a synthetic polymer having both a hydrophobic moiety and another moiety selected from the group consisting of an ionic moiety and a hydrophilic moiety, to give the material a property to change its electric resistance depending upon the moisture content in the atmosphere, said coating being formed by applying a latex comprising the synthetic polymer to said electrodes, the particles forming said latex having the hydrophobic moiety forming a core of each latex particle and the another moiety forming a surface layer on the core of each latex particle.
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32. A humidity-sensitive element comprising an insulating substrate having a first electric insulating layer formed of silicon dioxide on a silicon semiconductor substrate and a second electric insulating layer, formed of silicon nitride, on the first electric insulating layer;
- a pair of electrodes formed thereon apart from each other by a definite distance, said pair of electrodes being a pair of conductive polysilicon electrodes formed on the second insulating layer to oppose each other with a narrow space therebetween, said conductive polysilicon electrodes being formed by implanting phosphorus ions or boron ions into the polysilicon; and
a coating of humidity-sensitive organic material formed to cover said electrodes, said coating of humidity-sensitive organic material being a synthetic polymer having a hydrophobic moiety and another moiety selected from the group consisting of an ionic moiety and a hydrophilic moiety, to give the material a property to change its electric resistance depending upon the moisture content in the atmosphere, said coating being formed by applying a latex comprising the synthetic polymer to said electrodes, the particles forming said latex having the hydrophobic moiety forming a core of each latex particle and the another moiety forming a surface layer on the core of each latex particle. - View Dependent Claims (33)
- a pair of electrodes formed thereon apart from each other by a definite distance, said pair of electrodes being a pair of conductive polysilicon electrodes formed on the second insulating layer to oppose each other with a narrow space therebetween, said conductive polysilicon electrodes being formed by implanting phosphorus ions or boron ions into the polysilicon; and
Specification