Padless touch sensor
First Claim
1. A padless touch sensor for detecting a touch at a sensing location onto a dielectric element by a user coupled to earth, the sensor comprising:
- a conductive plate;
a means for attaching the conductive plate under the dielectric element and in registry with the sensing location;
a means for applying a predetermined potential on the conductive plate;
a test pulse generating means for producing test pulses into earth; and
a means responsive to a potential variation in the conductive plate for producing an output signal indicative of the potential variation;
whereby, when the user touches the dielectric element at the sensing location, a potential variation occurs in the conductive plate during a test pulse due to a capacitive circuit formed between earth, the user and the means responsive to the potential variation.
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Accused Products
Abstract
The padless touch sensor is used for detecting a touch at a sensing location onto a dielectric element by a user coupled to earth. The sensor comprises a conductive plate attached under the dielectric element and in registry with the sensing location. A predetermined potential is applied on the conductive plate. Simultaneously, test pulses are produced into earth. When the user touches the dielectric element at the sensing location, a potential variation in the conductive plate is produced during a test pulse due to a capacitive circuit formed between earth, the user and the sensor. No deposition of conductive pads on the dielectric element or other special processes are required. Foreign matter or objects placed directly on top of the dielectric element will not erroneously produce a touch condition.
97 Citations
18 Claims
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1. A padless touch sensor for detecting a touch at a sensing location onto a dielectric element by a user coupled to earth, the sensor comprising:
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a conductive plate; a means for attaching the conductive plate under the dielectric element and in registry with the sensing location; a means for applying a predetermined potential on the conductive plate; a test pulse generating means for producing test pulses into earth; and a means responsive to a potential variation in the conductive plate for producing an output signal indicative of the potential variation; whereby, when the user touches the dielectric element at the sensing location, a potential variation occurs in the conductive plate during a test pulse due to a capacitive circuit formed between earth, the user and the means responsive to the potential variation. - View Dependent Claims (2, 3)
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4. A padless touch sensor for detecting a touch at sensing locations onto a dielectric element by a user coupled to earth, the sensor comprising:
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a plurality of conductive plates, one for each sensing location; a means for attaching each conductive plate under the dielectric element and in registry with a respective sensing location; a means for successively applying a predetermined potential on one of the conductive plates at once; a test pulse generating means for producing a test pulse into earth while one of the conductive plates receives the predetermined potential; and a means responsive to a potential variation in the conductive plate with the predetermined potential for producing an output signal indicative of the potential variation in that conductive plate; whereby, when the user touches the dielectric element at one of the sensing locations, a potential variation occurs in the conductive plate during a test pulse due to a capacitive circuit formed between earth, the user and the means responsive to the potential variation. - View Dependent Claims (5, 6, 7)
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8. A padless touch sensor for detecting a touch at sensing locations onto a dielectric element by a user coupled to earth, the sensor comprising:
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a plurality of conductive plates, one for each sensing location; a means for attaching each conductive plate under the dielectric element and in registry with a respective sensing location; a means for applying a predetermined potential on the conductive plates; a test pulse generating means for producing test pulses into earth; and a means responsive to a potential variation in the conductive plates with the predetermined potential for producing output signals indicative of the potential variation in each of the conductive plates; whereby, when the user touches the dielectric element at one of the sensing locations, a potential variation occurs in the corresponding conductive plate during a test pulse due to a capacitive circuit formed between earth, the user and the means responsive to the potential variation. - View Dependent Claims (9, 10)
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11. A method for detecting a touch at a sensing location onto a dielectric element by a user coupled to earth, the method comprising the steps of:
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applying a predetermined potential on a conductive plate attached under the dielectric element and in registry with the sensing location; producing test pulses into earth; sensing a potential variation on the conductive plate; and producing an output signal indicative of the potential variation. - View Dependent Claims (12)
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13. A method for detecting a touch at sensing locations onto a dielectric element by a user coupled to earth, each sensing location being provided with a corresponding conductive plate attached under the dielectric element and in registry with the respective sensing location, the method comprising the steps of:
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successively applying a predetermined potential on one of the conductive plates at once; producing a test pulse into earth while the predetermined potential is applied on one conductive plate; sensing a potential variation in each of the conductive plates while the predetermined potential is applied thereon; and producing an output signal indicative of the potential variation in each of the conductive plates while the predetermined potential is individually applied thereon. - View Dependent Claims (14, 15, 16)
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17. A method for detecting a touch at sensing locations onto a dielectric element by a user coupled to earth, each sensing location being provided with a corresponding conductive plate attached under the dielectric element and in registry with the respective sensing location, the method comprising the steps of:
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applying a predetermined potential on the conductive plates; producing test pulses into earth; sensing a potential variation in each of the conductive plates; and producing output signals indicative of the potential variation in each of the conductive plates while they are being sensed. - View Dependent Claims (18)
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Specification