Pulsed pen for use with a digitizer tablet
First Claim
1. An inductive pen for use with a digitizer tablet of a type that includes a fixed array of inductors and means for determining a magnitude of a mutual inductance between the fixed array of inductors and the inductive pen for estimating a position of the inductive pen relative to a coordinate system associated with the fixed array of inductors, wherein the inductive pen includes means for autonomously transmitting pulses each of which includes an electromagnetic energy signal having a characteristic frequency.
1 Assignment
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Accused Products
Abstract
An inductive pen (16) repetitively transmits pulses of an oscillatory signal having a characteristic frequency. Pen state information, such as pen tip contact switch information, are encoded by a number of techniques. These techniques include pulse width modulation or pulse position modulation, so as to convey pen state information to a digitizing tablet in a manner that does not adversely affect pen position determinations. The pen state information may also be encoded on the oscillating signal by Frequency Shift Keying (FSK), Phase Shift Keying (PSK), or Amplitude Modulation (AM). A digitizer tablet (10) includes circuitry for detecting the transmitted pen state information, the circuitry accommodating the selected modulation scheme. The tablet is responsive to the transmitted pulses for placing tablet circuitry in a low-power consumption state between pulses so as to conserve tablet power.
128 Citations
27 Claims
- 1. An inductive pen for use with a digitizer tablet of a type that includes a fixed array of inductors and means for determining a magnitude of a mutual inductance between the fixed array of inductors and the inductive pen for estimating a position of the inductive pen relative to a coordinate system associated with the fixed array of inductors, wherein the inductive pen includes means for autonomously transmitting pulses each of which includes an electromagnetic energy signal having a characteristic frequency.
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12. A digitizer tablet, comprising:
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an array of conductors defining a sensing plane for sensing a pulsed, oscillating, electromagnetic signal generated external to the sensing plane; means, coupled to the array of conductors, for determining a magnitude of an electrical signal or signals induced within the array of conductors by the pulsed electromagnetic signal; and means, coupled to an output of the determining means and responsive to the determined magnitude, for estimating a position of a source of the pulsed electromagnetic signal relative to a coordinate system associated with the sensing plane;
whereinthe pulses of electromagnetic energy are modulated for conveying information, and wherein the determining means includes means for decoding the information conveyed by the pulses. - View Dependent Claims (13, 14, 15, 16)
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17. An inductive pen for use with a digitizer tablet, the inductive pen comprising:
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an inductive coil; and means for autonomously causing the inductive coil to repetitively transmit pulses of an oscillatory signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification