Ultrasonic touch system
First Claim
1. An ultrasonic touch system comprising:
- a substrate;
at least one ultrasonic transducing system on one surface of said substrate, said ultrasonic transducing system comprising emitting transducers (T) and receiving transducers (R) corresponding to said emitting transducers, said emitting and receiving transducers being arranged to face each other on said surface of said substrate making a pair so that a transmitting direction of an acoustic wave generated by one of said emitting transducers is the same as the receiving direction of said acoustic wave by a corresponding one of said receiving transducers;
means for applying an electric signal to said emitting transducers for exciting said acoustic wave;
means for delivering an electric signal, having a frequency approximately corresponding to the wavelength of said acoustic wave, generated from said receiving transducers;
means for determining a touch on a part of the substrate where the acoustic wave propagates in reliance on a magnitude of said electric signal delivered by said means for delivering;
said emitting and receiving transducers each comprising sets of interdigital transducers, wherein said means for applying an electric signal to said emitting transducers is for applying an electric signal having a frequency approximately corresponding to an interdigital periodicity of one of said sets of interdigital emitting transducers so that said acoustic wave is generated on said surface having a wavelength approximately equal to said interdigital periodicity; and
wherein said sets of interdigital emitting and receiving transducers have at least two interdigital periodicities varying in a direction perpendicular to said interdigital transducers.
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Accused Products
Abstract
An ultrasonic touch system including a substrate and at least an ultrasonic transducing system on one end surface Z1 of the substrate. The ultrasonic transducing system comprises at least an interdigital transducer P and at least an interdigital transducer Q corresponding to the interdigital transducer P. An electric signal having a frequency approximately corresponding to the interdigital periodicity of the interdigital transducer P is applied to the interdigital transducer P, causing the acoustic wave on the end surface Z1 with a high efficiency, the acoustic wave having a wavelength approximately equal to the interdigital periodicity of the interdigital transducer P. At this time, an electric signal having a frequency approximately corresponding to the wavelength of the acoustic wave generated on the end surface Z1 is detected at the interdigital transducer Q. When touching with a finger or other things on a part of the propagation medium of the acoustic wave on the end surface Z1, the electric signal detected at the interdigital transducer Q is decreased. A touch on the substrate by a finger or other things is accordingly detected with a high sensitivity and a quick response time under operation with low power consumption and low voltage.
72 Citations
15 Claims
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1. An ultrasonic touch system comprising:
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a substrate; at least one ultrasonic transducing system on one surface of said substrate, said ultrasonic transducing system comprising emitting transducers (T) and receiving transducers (R) corresponding to said emitting transducers, said emitting and receiving transducers being arranged to face each other on said surface of said substrate making a pair so that a transmitting direction of an acoustic wave generated by one of said emitting transducers is the same as the receiving direction of said acoustic wave by a corresponding one of said receiving transducers; means for applying an electric signal to said emitting transducers for exciting said acoustic wave; means for delivering an electric signal, having a frequency approximately corresponding to the wavelength of said acoustic wave, generated from said receiving transducers; means for determining a touch on a part of the substrate where the acoustic wave propagates in reliance on a magnitude of said electric signal delivered by said means for delivering; said emitting and receiving transducers each comprising sets of interdigital transducers, wherein said means for applying an electric signal to said emitting transducers is for applying an electric signal having a frequency approximately corresponding to an interdigital periodicity of one of said sets of interdigital emitting transducers so that said acoustic wave is generated on said surface having a wavelength approximately equal to said interdigital periodicity; and wherein said sets of interdigital emitting and receiving transducers have at least two interdigital periodicities varying in a direction perpendicular to said interdigital transducers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A touch activated panel comprising:
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a substrate having an emitter transducer and a receiver transducer on a surface thereof which face each other so that an acoustic wave transmitted into said substrate by said emitter transducer is received by said receiver transducer, said two transducers being separated by a portion of said substrate which, when touched, modifies the acoustic wave received by said receiver transducer; each of said emitter and receiver transducers comprising, a first plurality of parallel interdigital transducer elements which are generally perpendicular to an axis of a propagation path between said emitter transducer and said receiver transducer and which are spaced apart to have a first interdigital periodicity, and a second plurality of interdigital transducer elements which are parallel to said first plurality of transducer elements and which are spaced apart to have a second interdigital periodicity, whereby said emitter and receiver transducers are responsive to frequencies corresponding to said first and second interdigital periodicities. - View Dependent Claims (15)
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Specification