Capacitance-type liquid sensor
First Claim
1. A liquid sensor comprising:
- a container filled with an electrically conductive liquid;
an electrode including a part having a surface formed with a dielectric film, the electrode being brought into contact with the conductive liquid so that a change in a contact area of the electrode with the conductive liquid with movement of a surface of the conductive liquid is measured from a change in a capacitance between the electrode and the conductive liquid and so that a change in a tilt angle of the electrode to the liquid surface or an acceleration applied to the container is detected from a measured value, wherein the dielectric film comprises a silicon oxide film.
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Accused Products
Abstract
A capacitance type liquid sensor is disclosed which detects a tilt angle and acceleration of an object using the fact that a liquid surface always keeps itself horizontal. Openings (13, 14) are formed in two sides of a hollow cylindrical closed container (6) made of an electrically insulating material, and the container has two parallel sides (2, 3). Plate-shaped main electrodes (4, 5) on at least one face of each of which silicon oxide film is formed are made to be in contact with the sides so as to close the openings, with the silicon oxide film being placed so as to face the inside of the container. A sealing agent (28) is interposed in a gap between the plate-shaped main electrodes and the sides. The container is filled with electrically conductive liquid (27) of an amount equal to substantially one-half of the inside volume of the container. An auxiliary electrode (8) brought into electrical contact with the conductive liquid is mounted in the container.
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Citations
45 Claims
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1. A liquid sensor comprising:
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a container filled with an electrically conductive liquid; an electrode including a part having a surface formed with a dielectric film, the electrode being brought into contact with the conductive liquid so that a change in a contact area of the electrode with the conductive liquid with movement of a surface of the conductive liquid is measured from a change in a capacitance between the electrode and the conductive liquid and so that a change in a tilt angle of the electrode to the liquid surface or an acceleration applied to the container is detected from a measured value, wherein the dielectric film comprises a silicon oxide film.
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2. A capacitance type liquid sensor comprising:
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a cylindrical closed container made from an electrically insulating material and having two sides parallel to each other, the sides having respective openings formed therein, the container being filled with a conductive liquid; a plurality of plate-shaped main electrodes each having at least one side formed with a silicon oxide film, the main electrodes being in abutment with said sides while the silicon oxide films face an inside of the container, thereby closing the openings; a sealing agent interposed in a gap between the main electrodes and said sides for fluid tightness respectively; and an auxiliary electrode provided in the container to be brought into electrical contact with the conductive liquid, wherein the conductive liquid has an amount corresponding to substantially one half of a content volume of the container. - View Dependent Claims (4, 8, 9, 16, 17, 18, 22, 25, 32, 37, 42)
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3. A capacitance type liquid sensor comprising:
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a cylindrical closed container made from an electrical insulator and having two sides parallel to each other and upper and lower openings closed by lids respectively, said sides having vertically extending rectangular openings formed in the sides; a plurality of notches formed by cutting out corners located outside the container with respect to all end faces of the openings so that plate-shaped members are capable of being fitted in the notches; a plurality of plate-shaped electrodes having at least one side formed with silicon oxide films and fitted in the notches so as to abut against bottoms of the notches with the oxide films facing an inside of the container; a sealing agent provided for fluid tightness in gaps defined between the bottoms of the notches and the plate-shaped electrodes and gaps defined between outer peripheral sides of the plate-shaped electrodes and sides of the notches; an electrically conductive liquid having an amount equal to substantially one-half of an inside volume of the container and filling the container; and an auxiliary electrode bar made from a metal and extending through substantially a central part of the upper lid so that a distal end thereof is immersed sufficiently deep in the conductive liquid. - View Dependent Claims (5, 6, 7, 19, 20, 21, 23, 24, 26, 31, 33, 36, 38, 41, 43)
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10. A capacitance type liquid sensor comprising:
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a closed container; an electrically conductive liquid having an amount equal to substantially one-half of an inside volume of the container and filling the container; a pair of lead terminals extending through one of ends of the container and fixed to the container so as to be electrically insulated from the container; a plurality of main electrodes having surfaces formed with silicon oxide films and mounted on distal ends of the lead terminals, respectively, the main electrodes being provided so that parts of the main electrodes are located on a liquid surface of the conductive liquid when the container is stationary; and an auxiliary electrode electrically conductively brought into contact with the conductive liquid. - View Dependent Claims (11, 12, 13, 14, 15, 27, 28, 29, 30, 34, 35, 39, 40, 44, 45)
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Specification