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US 4,849,852 AGranted
Variable capacitance push-button switch
AssigneeAlps Electric (USA) Inc.
InventorBarry Mullins
Life of this patent
Estimating the term…
Abstract
In a capacitive-type switch having two capacitive levels, a relatively thin blade of a desired dielectric material is interposed between two capacitive plates by downward actuation of a push-button switch so that the plates become separated by the blade. When the push button is released, the blade is removed from between the two capacitive plates and a high capacitance level is once again achieved.
Claims7
A capacitive switch comprising:
- a first capacitive plate having a first dielectric layer thereon;
- a second capacitive opposing said first capacitive plate and separated from said first capacitive plate by said dielectric layer when said switch is in a first position;
- means for applying a resilient force to said first and second capacitive plates so that said first and second capacitive plates are resiliently pressed against each other, while separated by said first dielectric layer, when said switch is in said first position;
- and
- a blade means of a desired thickness and dielectric constant, which, when said switch is actuated to be in a second position, interposes between said first and second capacitive plates, causing a change of capacitance between said first and second capacitive plates.
2 more elements
A method of causing a change in capacitance upon actuation of a push-button switch comprising:
- interposing a dielectric blade between two resiliently opposed capacitive plates, separated by a dielectric layer, upon depression of said push-button switch, causing said capacitive plates to be separated by at least the thickness of said dielectric blade, where upon release of said push button, said blade is removed from between said capacitive plates and said capacitive plates once again oppose each other through said dielectric layer by a resilient force.
Dependencies are inferred from the claim text.