Digitizer stylus with pressure transducer
First Claim
1. A stylus for use with a digitizer tablet having a working surface, comprising:
- a conductive tip for pressing against the working surface of said digitizer tablet;
a transducer having electrical resistance, said resistance varying with the amount of compressive force applied to said transducer;
a pair of electrodes conductively contacting said transducer and in electrical circuit with said variable resistance when said compressive force is applied, said tip being electrically insulated from said electrodes;
means for capacitively coupling said tip to one of said electrodes; and
mechanical means for transmitting to said transducer a compressive force substantially equal to the pressure being exerted on the working surface of said tablet by said tip, whereby the resistance of said transducer is a function of said pressure.
4 Assignments
0 Petitions
Accused Products
Abstract
A stylus switch is activated automatically when the tip of the stylus is pressed against a digitizer tablet with sufficient force. The pressure switch includes a transducer in the form of an ink layer having electrical resistance which varies as a function of the pressure applied thereon. Electrodes of conductive ink contact the ink layer of the transducer, providing a circuit element including a variable resistance. The current which flows between the two conductive ink electrodes varies as a function of the force with which the stylus tip is pressed against the data tablet, thus providing an analog output which can be detected as a function of pressure or which can be detected to determine when the pressing force exceeds a predetermined value. Processing of the data representing the coordinates of the stylus tip is enabled only when the tip is being pressed with at least a predetermined force, i.e. the amount of force applied by a stylus user during writing. The ink layers of the electrodes and transducer, as well as the stylus anode, are applied on a single piece of flexible plastic film which is wrapped around a central assembly and inside a coaxial barrel. A collapsible dome of metal is arranged to provide tactile feedback to the user when the predetermined force is obtained.
62 Citations
20 Claims
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1. A stylus for use with a digitizer tablet having a working surface, comprising:
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a conductive tip for pressing against the working surface of said digitizer tablet; a transducer having electrical resistance, said resistance varying with the amount of compressive force applied to said transducer; a pair of electrodes conductively contacting said transducer and in electrical circuit with said variable resistance when said compressive force is applied, said tip being electrically insulated from said electrodes; means for capacitively coupling said tip to one of said electrodes; and mechanical means for transmitting to said transducer a compressive force substantially equal to the pressure being exerted on the working surface of said tablet by said tip, whereby the resistance of said transducer is a function of said pressure. - View Dependent Claims (2, 3, 10, 11)
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4. A stylus for use with a digitizer tablet having a working surface, comprising:
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a tip for pressing against the working surface of said digitizer tablet; a transducer having electrical resistance, said resistance varying with the amount of compressive force applied to said transducer; a pair of electrodes conductively contacting said transducer and in electrical circuit with said variable resistance when said compressive force is applied; and mechanical means for transmitting to said transducer a compressive force substantially equal to the pressure being exerted on the working surface of said tablet by said tip, whereby the resistance of said transducer is a function of said pressure, said transducer including a layer of conductive ink having a resistance which changes as a function of the compressive force applied thereon, each of said electrodes including a layer of conductive ink which is electrically connected to said transducer when said tip is pressed against the working surface of said digitizer tablet, said layer of conductive ink of said transducer being applied on a first plastic backing layer and said layer of conductive ink of said electrodes being applied on a second plastic backing layer, said first and second backing layers being non-conductive. - View Dependent Claims (5, 6, 7)
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8. A stylus for use with a digitizer tablet having a working surface, comprising:
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a tip for pressing against the working surface of said digitizer tablet; a transducer having electrical resistance, said resistance varying with the amount of compressive force applied to said transducer; a pair of electrodes conductively contacting said transducer and in electrical circuit with said variable resistance when said compressive force is applied; and mechanical means for transmitting to said transducer a compressive force substantially equal to the pressure being exerted on the working surface of said tablet by said tip, whereby the resistance of said transducer is a function of said pressure, said transducer including a layer of conductive ink having a resistance which changes as a function of the compressive force applied thereon, each of said electrodes including a layer of conductive ink which is electrically connected to said transducer when said tip is pressed against the working surface of said digitizer tablet, said mechanical means for transmitting force being constructed to apply said compressive force to said ink layer of said transducer over an area which increases as said compressive force increases, the resistance of said ink layer of said transducer being dependent on both the magnitude of said compressive force and the area of said ink layer of said transducer to which said force is applied. - View Dependent Claims (9)
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12. A stylus for use with a digitizer tablet having a working surface, comprising:
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a conductive tip for pressing against the working surface of said digitizer tablet; switch means electrically insulated from said tip for changing from a first state to a second state in response to a predetermined compressive force applied to said switch means, said switch means having first and second terminals; means capacitively coupling one of said terminals to said tip; and mechanical means for transmitting to said switch means a compressive force substantially equal to the pressure being exerted on the working surface of said digitizer tablet by said tip, whereby said switch state is changed in response to the pressure surpassing said predetermined compressive force. - View Dependent Claims (13, 14, 15)
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16. A stylus for use with a digitizer tablet having a working surface and a first electrode, comprising:
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a sleeve-shaped casing having an axis; a conductive tip for pressing against the working surface of said digitizer tablet, said tip projecting from an end of said casing; an anode capacitively coupled to said first electrode of said digitizer tablet via said tip; a terminal electrically connected to said anode for outputting a signal produced during capacitive coupling of said anode; and a thin substrate made of flexible material, and wrapped inside said casing, wherein said anode and said terminal are applied on said thin substrate.
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17. A stylus for use with a digitizer tablet having a working surface and a first electrode, comprising:
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a sleeve-shaped casing having an axis; a tip for pressing against the working surface of said digitizer tablet, said tip projecting from an end of said casing; an anode capable of being capacitively coupled to said first electrode of said digitizer tablet; a terminal electrically connected to said anode for outputting a signal produced during capacitive coupling of said anode; and a thin substrate made of flexible material, and wrapped inside said casing, wherein said anode and said terminal are applied on said thin substrate, said stylus further comprising; a transducer having electrical resistance, said resistance varying with the magnitude of a compressive force applied to said transducer; a pair of electrodes conductively contacting said transducer during application of said compressive force; and mechanical means for transmitting to said transducer a compressive force substantially equal to the pressure being exerted on the working surface of said tablet by said, whereby the resistance of said transducer is a function of said pressure; wherein said transducer and said pair of electrodes are respectively applied on said thin substrate. - View Dependent Claims (18, 19, 20)
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Specification