Capacitive sensing and data input device power management
First Claim
1. A capacitive sensing system for sensing the presence of an object or body portion in contact with or close proximity to another object, comprising:
- a first conductor capacitively coupled to a ground to thereby form a scoop capacitor having a capacitance which varies in relation to the proximity of said object or body portion to said conductor;
a pair of second and third conductors forming a bucket capacitor having a capacitance which is larger than a maximum capacitance of said scoop capacitor;
an input threshold switch;
switching means for selectively;
connecting at least one of said scoop capacitor and bucket capacitor to a voltage source to charge said at least one capacitor, varying the charge of said bucket capacitor in relation to a relative size of said scoop capacitor, and applying a voltage of said bucket capacitor to said input threshold switch;
detector means for detecting an input state of said input threshold switch;
determining means for determining a value (TouchVal) relating to a number of cycles of said varying of the bucket capacitor charge, corresponding to a detection of a transition of said input threshold switch by said detector means; and
signal generating means for generating, based upon TouchVal, a signal indicative of an ON state wherein said object or body portion is in contact with or close proximity to said another object, and an OFF state wherein said object or body portion is not in contact with or close proximity to said another object.
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Accused Products
Abstract
Capacitive proximity sensing is carried out by detecting a relative change in the capacitance of a “scoop” capacitor formed by a conductor and a surrounding ground plane. The conductor may be a plate provided in the form of an adhesive label printed with conductive ink. Charge is transferred between the “scoop” capacitor and a relatively large “bucket” capacitor, and a voltage of the bucket capacitor is applied to an input threshold switch. A state transition (e.g., from low to high, or high to low) of the input threshold switch is detected and a value (TouchVal) indicative of a number of cycles of charge transfer required to reach the state transition is determined. The presence or absence of an object or body portion in close proximity to or contact with a device can be determined by comparing TouchVal with a predetermined threshold value (TouchOff). TouchOff can be adjusted to take into account environmentally induced (non-touch related) changes in the capacitance of the scoop capacitor. Power management is provided in a user operated data input device utilizing proximity sensing and switching between three or more power states. Switching between the power states occurs based upon the presence or absence of input activity, and an operation instrumentality (e.g., a hand) in close proximity to or contact with the device. In an optical surface tracking cursor control device embodiment, switching to and from a BEACON state, which provides a reduced flash rate of a surface illuminating light source, is carried out based upon a detected presence or absence of a trackable surface.
73 Citations
102 Claims
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1. A capacitive sensing system for sensing the presence of an object or body portion in contact with or close proximity to another object, comprising:
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a first conductor capacitively coupled to a ground to thereby form a scoop capacitor having a capacitance which varies in relation to the proximity of said object or body portion to said conductor;
a pair of second and third conductors forming a bucket capacitor having a capacitance which is larger than a maximum capacitance of said scoop capacitor;
an input threshold switch;
switching means for selectively;
connecting at least one of said scoop capacitor and bucket capacitor to a voltage source to charge said at least one capacitor, varying the charge of said bucket capacitor in relation to a relative size of said scoop capacitor, and applying a voltage of said bucket capacitor to said input threshold switch;
detector means for detecting an input state of said input threshold switch;
determining means for determining a value (TouchVal) relating to a number of cycles of said varying of the bucket capacitor charge, corresponding to a detection of a transition of said input threshold switch by said detector means; and
signal generating means for generating, based upon TouchVal, a signal indicative of an ON state wherein said object or body portion is in contact with or close proximity to said another object, and an OFF state wherein said object or body portion is not in contact with or close proximity to said another object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 59, 60)
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28. A user operated data input device comprising:
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first and second data input signal generating means for generating respective first and second data input signals;
a power supply for selectively supplying electrical power to said first and second input signal generating means;
a sensing system for sensing the presence of an operation instrumentality in contact with or close proximity to said input device and generating a signal indicative of an ON state wherein said operation instrumentality is in contact with or close proximity to said input device, and an OFF state wherein said operation instrumentality is not in contact with or close proximity to said input device;
a power management system for controlling the supply of power to said first and second input signal generating means, said power management system providing switching between at least three power states, wherein;
in a first of said power states each of said first and second input signal generating means is powered-up to a normal operation level and sampled for input activity;
in a second of said power states each of said first and second input signal generating means are cycled between a powered-up state wherein sampling for input activity is carried out, and a powered down state;
in a third of said power states said first signal generating means remains powered down while said second signal generating means is cycled between a powered-up state wherein sampling for input activity is carried out, and a powered down state;
a transition from said first power state to said third power state occurs upon a transition of said sensing system from said ON state to said OFF state;
a transition from said third power state to one of said first and second power states occurs upon a transition of said sensing system from said OFF state to said ON state; and
a transition from said second power state to said first power state occurs upon a detection of input activity during said sampling of said first and second input signal generating means.
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56. A hand-held cursor control device comprising:
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an optical tracking engine including a light source which is flashed;
detector means for detecting light from said light source which has been reflected off of a surface;
determining means for determining the presence or absence of a trackable surface;
and control means for controlling said light source such that (a) when said determining means determines the presence of a trackable surface said light source is flashed at a first rate permitting tracking of said surface, and (b) when said determining means determines the absence of a trackable surface said light source is flashed at a second rate lower than said first rate.
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61. A method for sensing the presence of an object or body portion in contact with or close proximity to another object, comprising:
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providing a first conductor capacitively coupled to a ground to thereby form a scoop capacitor having a capacitance which varies in relation to the proximity of said object or body portion to said conductor;
a pair of second and third conductors forming a bucket capacitor having a capacitance which is larger than a maximum capacitance of said scoop capacitor; and
an input threshold switch;
performing switching to selectively;
connect at least one of said scoop capacitor and said bucket capacitor to a voltage source to charge said at least one capacitor, vary the charge of said bucket capacitor in relation to a relative size of said scoop capacitor, and apply a voltage of said bucket capacitor to said input threshold switch;
detecting an input state of said input threshold switch;
determining a value (TouchVal) relating to a number of cycles of said varying of the bucket capacitor charge, corresponding to a detection of a transition of said input threshold switch; and
generating, based upon TouchVal, a signal indicative of an ON state wherein said object or body portion is in contact with or close proximity to said another object, and an OFF state wherein said object or body portion is not in contact with or close proximity to said object. - View Dependent Claims (62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93)
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78. In a user operated data input device comprising first and second data input signal generating means for generating respective first and second data input signals, and a power supply for selectively supplying electrical power to said first and second input signal generating means, a method of power management comprising:
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sensing the presence of an operation instrumentality in contact with or close proximity to said input device and generating a signal indicative of an ON state wherein said operation instrumentality is in contact with or close proximity to said input device, and an OFF state wherein said operation instrumentality is not in contact with or close proximity to said input device;
controlling the supply of power to said first and second input signal generating means by providing switching between at least three power states, wherein;
in a first of said power states each of said first and second input signal generating means is powered-up to a normal operation level and sampled for input activity;
in a second of said power states each of said first and second input signal generating means are cycled between a powered-up state wherein sampling for input activity is carried out, and a powered down state;
in a third of said power states said first signal generating means remains powered down while said second signal generating means is cycled between a powered-up state wherein sampling for input activity is carried out, and a powered down state;
a transition from said first power state to said third power state occurs upon a transition of said sensing system from said ON state to said OFF state;
a transition from said third power state to one of said first and second power states occurs upon a transition of said sensing system from said OFF state to said ON state; and
a transition from said second power state to said first power state occurs upon a detection of input activity during said sampling of said first and second input signal generating means.
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94. In a hand-held cursor control device comprising an optical tracking engine including a light source which is flashed, a method of operation comprising:
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detecting light from said light source which has been reflected off of a surface;
determining the presence or absence of a trackable surface; and
controlling said light source such that (a) when the presence of a trackable surface is determined said light source is flashed at a first rate permitting tracking of said surface, and (b) when the absence of a trackable surface is determined said light source is flashed at a second rate lower than said first rate. - View Dependent Claims (95, 96)
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- 97. An electronic device comprising a housing and a capacitive sensing system contained within said housing for sensing the presence of an operation instrumentality in contact with or close proximity to said electronic device and generating a signal indicative of an ON state wherein an operation instrumentality is in contact with or close proximity to said electronic device, and an OFF state wherein said operation instrumentality is not in contact with or close proximity to said electronic device, said capacitive sensing system comprising a conductive sensor plate in the form of a flexible label adhesively applied to said housing.
Specification