Apparatus and method for sensing the degree and touch strength of a human body on a sensor
AssigneeMcQuint, Inc.
InventorWonchan Kim
Life of this patent
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Abstract
An improvement in sensor for detecting contact with a human resistive element is disclosed. This design uses additional components to avoid discharging capacitors through the human resistive element, thereby sparing the user the uncomfortable sensation associated therewith and increasing the power requirements of the device. In addition, designs are utilized which multiple sensing points are multiplexed to achieve greater resolution while with a lower pin count at the signal processing chip.
Claims22
A sensor for sensing the contact level of a human body comprising:
- a first capacitor having one end connected to ground;
- a second capacitor connected in series with said first capacitor and defining a node therebetween;
- a charging element, for delivering a charge to said first capacitor;
- a sensing point connected in series with said second capacitor, said sensing point being capable of defining a resistance when in contact with a human resistive element;
- and
- an output device for detecting when the voltage at said node falls below a pre-defined threshold value as the result of the leakage of said charge from said first capacitor to said second capacitor.
A sensor for sensing the contact level of a human body comprising:
- a first capacitor having one end connected to ground;
- a second capacitor connected in series with said first capacitor and defining a node therebetween;
- a charging element, for delivering a charge to said first capacitor;
- a sensing point connected in series with said second capacitor, said sensing point being capable of defining a resistance when in contact with a human resistive element;
- wherein said first and second capacitors, when combined with said resistance of said sensing point form an RC circuit which causes the charge stored on said first capacitor to flow to said second capacitor, causing the voltage at said node to fall;
- and
- an output device for detecting when the voltage at said node falls below a pre-defined threshold value.
A sensor for sensing the contact level of a human body comprising:
- a plurality of sensing devices arranged in parallel, each of said sensing devices having a selection node initially connected to ground;
- a capacitor, connected in series with said plurality parallel of sensing devices, defining a node therebetween;
- a current source for delivering a charge to said capacitor;
- a current sink for draining said current from said capacitor;
- and
- an output device for outputting a signal based on the voltage at said node.
A method for sensing the level of contact between a sensing point and a human body comprising the steps of:
- charging a first capacitor;
- allowing said charge to leak from said first capacitor to a second capacitor when a sensing point connected to said second capacitor comes in contact with a human body;
- and
- signaling when said voltage across said first capacitor falls below a threshold value.
A method for sensing the level of contact between a sensing point and a human body comprising the steps of:
- providing a first capacitor;
- providing a second capacitor connected in series with said first capacitor and defining a node therebetween;
- providing a sensing point in series with said second capacitor, said sensing point defining a resistance between ground and said second capacitor when in contact with a human body;
- charging said first capacitor until a predetermined voltage at said node is reached;
- monitoring the leakage of said charge stored on said first capacitor to said second capacitor via the decrease in voltage at said node;
- and
- signaling when said voltage at said node falls below a pre-defined threshold value.
A method for sensing the level of contact between a sensing point and a human body comprising the steps of:
- charging a first capacitor connected between ground and a node to a voltage below a threshold voltage;
- applying a selecting voltage to one of a plurality of sensing devices, said selecting voltage causing the voltage at said node to rise to a voltage above said threshold voltage;
- outputting a signal if said voltage at said node falls below said threshold voltage;
- and
- deselecting said selected sensing device by grounding said selecting node.
An improvement to a sensor for sensing human contact comprising a sensing point capable of defining a resistance to ground when in contact with a human resistive element and a first capacitor connected in series with said sensing point, said improvement comprising:
- a second capacitor arranged in series between said sensing point and said first capacitor such that, when said sensing point defines a resistance, current is transferred from said first capacitor to said second capacitor instead of through said human resistive element.
Dependencies are inferred from the claim text.