Trackpad pen for use with computer touchpad
First Claim
1. An accessory for use with a computer touchpad that uses a periodic AC signal coupled to at least one electrode of a capacitor to detect a change in charging time of the capacitor caused by a user'"'"'s finger coming into contact with the computer touchpad, said accessory comprising:
- an approximately pen shaped housing;
a conductive tip positioned on a tip of the pen shaped housing;
a signal detector coupled to said conductive tip for detecting said periodic AC signal when said conductive tip is placed into contact with said computer touch pad;
a signal generator for generating a negative voltage transition with respect to said detected periodic AC signal that is coupled to said computer touchpad through said conductive tip to increase a charge time of said capacitor in a manner that approximates an increase in charge time of the capacitor that results from the user'"'"'s finger coming into contact with the computer touchpad.
15 Assignments
0 Petitions
Accused Products
Abstract
A pen or stylus for use with a finger activated computer touchpad uses capacitively coupled voltage signals to simulate the capacitive effect of a finger on the touchpad. In addition, the pen has buttons that can be utilized to capacitively couple control signals to the touchpad that are interpreted by application software as specific user-defined inputs. The pen has a conductive tip that is placed into contact with the touchpad. By biasing the touchpad electrodes with a properly timed voltage signal, the pen alters the charging time of the electrodes in the touchpad. This alteration in charging time is interpreted by the touchpad as a change in capacitance due to the presence of a user'"'"'s finger. Thus, the pen can be used with touchpads that were designed to only detect finger movements.
135 Citations
6 Claims
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1. An accessory for use with a computer touchpad that uses a periodic AC signal coupled to at least one electrode of a capacitor to detect a change in charging time of the capacitor caused by a user'"'"'s finger coming into contact with the computer touchpad, said accessory comprising:
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an approximately pen shaped housing; a conductive tip positioned on a tip of the pen shaped housing; a signal detector coupled to said conductive tip for detecting said periodic AC signal when said conductive tip is placed into contact with said computer touch pad; a signal generator for generating a negative voltage transition with respect to said detected periodic AC signal that is coupled to said computer touchpad through said conductive tip to increase a charge time of said capacitor in a manner that approximates an increase in charge time of the capacitor that results from the user'"'"'s finger coming into contact with the computer touchpad. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification