Methods and apparatus for capacitively detecting key motion and finger presence on a magnetic keyboard key
First Claim
Patent Images
1. A key assembly for use in a keyboard, the assembly comprising:
- a key guide including a first magnetic component;
a keycap including a second magnetic component and configured to be pressed downwardly relative to the key guide; and
a first keystroke sensor comprising a transmitter electrode and a receiver electrode, wherein the transmitter electrode and the receiver electrode are configured to measure a variable capacitance affected by a change in a capacitive coupling between the first and second magnetic components occurring during a keystroke.
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Abstract
Devices and methods for capacitively sensing key cap position during the initial and latter stages of a keystroke. A key assembly includes a stationary key guide magnet, a movable key cap magnet, and a transmitter/receiver electrode pair. One or both of the electrodes underlies the key cap. The capacitance change between the electrodes during a keystroke includes the capacitance change between the key cap and the electrode pair, and the change in capacitance between the key cap and the key guide. Key cap position may thus be accurately detected throughout the entire keystroke.
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Citations
20 Claims
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1. A key assembly for use in a keyboard, the assembly comprising:
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a key guide including a first magnetic component; a keycap including a second magnetic component and configured to be pressed downwardly relative to the key guide; and a first keystroke sensor comprising a transmitter electrode and a receiver electrode, wherein the transmitter electrode and the receiver electrode are configured to measure a variable capacitance affected by a change in a capacitive coupling between the first and second magnetic components occurring during a keystroke. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of detecting keystroke motions responsive to applied force by an input object, the method comprising:
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determining a keystroke motion based on changes in a first capacitance, a second capacitance, and a third capacitance, wherein the first capacitance is formed between a first magnetic component in a stationary key guide and a second magnetic component in a keyboard keycap, wherein the second capacitance is formed between a receiver electrode in a stationary keystroke sensor and the second magnetic component in the keycap, and wherein the third capacitance is formed between a transmitter electrode in the stationary keystroke sensor and the second magnetic component in the keycap. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A processing system for detecting keystroke motions, the processing system comprising:
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circuitry configured to be communicatively coupled to a plurality of key assemblies of a keyboard, the plurality of key assemblies comprising a keyboard keycap and a stationary key guide, wherein the circuitry is configured to; determine a keystroke motion based on changes in a first capacitance, a second capacitance, and a third capacitance, wherein the first capacitance is formed between a first magnetic component in the stationary key guide and a second magnetic component in the keyboard keycap, wherein the second capacitance is formed between a receiver electrode in a stationary keystroke sensor and the second magnetic component in the keyboard keycap, and wherein the third capacitance is formed between a transmitter electrode in the stationary keystroke sensor and the second magnetic component in the keycap. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification