Digitizing stylus having capacitive pressure and contact sensing capabilities
First Claim
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1. An assembly for sensing pressure applied to a contact surface, said assembly comprising:
- a housing;
a stylus mounted in said housing for movement relative thereto;
an electrical circuit associated with at least one of said housing and said stylus for detecting and quantifying pressure exerted on said stylus as a result of said stylus engaging said contact surface, said electrical circuit comprising a capacitor having one plate mounted on said stylus and another plate mounted on said housing so that movement of said stylus as a result of said stylus engaging said contact surface varies a capacitance of said capacitor;
spring means normally applying a predetermined pressure against said one capacitor plate to urge said one capacitor plate in a direction towards said other capacitor plate and opposite the direction of said pressure exerted on said stylus by said contact surface; and
means for varying said predetermined pressure on said spring to vary an initial contact threshold and an operating range of said electrical circuit.
1 Assignment
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Accused Products
Abstract
A stylus assembly in which a stylus is mounted in a housing for movement relative thereto. An electrical circuit is provided for sensing contact of the stylus with a writing surface and measuring the pressure exerted on the surface by the stylus.
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Citations
7 Claims
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1. An assembly for sensing pressure applied to a contact surface, said assembly comprising:
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a housing; a stylus mounted in said housing for movement relative thereto; an electrical circuit associated with at least one of said housing and said stylus for detecting and quantifying pressure exerted on said stylus as a result of said stylus engaging said contact surface, said electrical circuit comprising a capacitor having one plate mounted on said stylus and another plate mounted on said housing so that movement of said stylus as a result of said stylus engaging said contact surface varies a capacitance of said capacitor; spring means normally applying a predetermined pressure against said one capacitor plate to urge said one capacitor plate in a direction towards said other capacitor plate and opposite the direction of said pressure exerted on said stylus by said contact surface; and means for varying said predetermined pressure on said spring to vary an initial contact threshold and an operating range of said electrical circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification