Surface acoustic wave touch panel system

• US 4,644,100 A
• Filed: 03/22/1985
• Issued: 02/17/1987
• Est. Priority Date: 03/22/1985
• Status: Expired due to Term

• Current Assignee: Zenith Electronics Corporation (LG Corporation)
• Original Assignee: Zenith Electronics Corporation (LG Corporation)
• Inventors: Brenner, Michael C., Fitzgibbon, James J.
• Primary Examiner(s): SCHREYER, STAFFORD
• Application Number:
  US06/715,134
• Time in Patent Office: 697 Days
• Field of Search: 178/18, 178/19, 178/20, 340/365, 367/117, 367/127, 367/907
• US Class Current: 178/18.04
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate

Abstract

A system for recognizing and locating a touch induced perturbation of a surface acoustic wave propagating along one of a multiplicity of paths disposed transverse to a predetermined coordinate axis on a surface of a touch panel and for utilizing the magnitude of the perturbation to produce a control effect. The system comprises a substrate having a surface capable of propagating surface acoustic waves and is so characterized that a touch on that surface causes amplitude damping of a surface wave passing through the region of touch which damping is related to touch pressure. A transducer, responsive to touch-perturbated surface waves develops an output signal having a first characteristic indicative of the position of the touch on the substrate surface and having a second characteristic indicative of touch pressure.

A control system, which includes a memory and a computer, upon receipt of the output signal, responds to the first characteristic to develop a first control signal reflecting the location of the touch and responds to the second characteristic to develop a second control signal reflecting touch pressure.

Claims

1. A touch panel system, comprising:

a substrate having an acoustic surface wave propagating touch surface;

means for generating and receiving surface acoustic waves on said touch surface;

means responsive to a surface wave absorbing touch on said touch surface for developing an output signal representative of the degree of absorption of said surface acoustic waves by said touch, said signal having a first characteristic indicative of the position of the touch on said touch surface and a second characteristic indicative of the touch pressure; and

means for receiving said output signal and responsive to said first characteristic for identifying a predetermined controllable function and responsive to said second characteristic for controlling said controllable function.

2. A touch panel system, comprising:

a substrate having an acoustic surface wave propagating touch surface;

means for generating and receiving surface acoustic waves on said touch surface;

means responsive to a surface wave absorbing touch on said touch surface for developing an output signal representative of the degree of absorption of said surface acoustic waves by said touch, said signal having a first characteristic indicative of the positon of the touch on said touch surface and a second characteristic indicative of the touch pressure; and

means for receiving said output signal and responsive to said first characteristic for developing a first control signal reflecting said touch position and responsive to said second characteristic for developing a second control signal reflecting said touch pressure.

10. The apparatus defined by claim 2, 3, 5 or 8 wherein said means for developing said first and second control signals includes means for:

(a) sampling the amplitude of the rectified output from said output transducer means at a plurality of time spaced points,

(b) storing the amplitude samples for future reference,

(c) during a touch of the apparatus, again sampling the amplitude of the said output transducer output and comparing the developed touch-related amplitude samples with the stored reference samples, and

(d) developing said first control signal representing the timing-related point of greatest difference between the amplitudes of said reference samples and said touch-related samples and thus the timing of said touch-perturbed wave burst, and developing said second control signal representing the magnitude of the said greatest difference.

3. A touch panel system, comprising:

a substrate having an acoustic surface wave propagating touch surface;

means for generating and receiving surface acoustic waves on said touch surface;

means responsive to a surface wave absorbing touch on said touch surface for developing an output signal representative of the degree of absorption of said surface acoustic waves by said touch, said signal having a first characteristic indicative of the position of the touch on said touch surface and a second characteristic indicative of plural discrete non-zero levels of touch pressure or a continuum of levels of touch pressure; and

circuit means responsive to said first characteristic for developing a first signal containing information indicative of the position of the touch, and responsive to said second characteristic for developing a second signal containing information indicative of plural discrete non-zero levels of touch pressure or a continuum of levels of touch pressure.

4. A surface acoustic wave touch panel system, comprising:

a substrate having a touch surface capable of propagating surface waves;

means including surface wave transducer means for launching and receiving surface waves on said surface;

means responsive to a surface wave absorbing touch on said surface for developing an output signal representative of the degree of absorption of said surface acoustic waves by said touch, said signal having a first wave-timing-related characteristic and a second characteristic indicative of plural discrete non-zero levels of damping or a continuum of levels of damping of said surface acoustic waves propagating on said surface through the region of the touch; and

means receiving said output signal and responsive to said first characteristic for identifying a controllable function and responsive to said second characteristic for controlling said controllable function.

5. A surface acoustic wave touch panel system, comprising:

a substrate having a touch surface capable of propagating surface waves;

means including surface wave transducer means for launching and receiving surface waves on said surface;

means responsive to a surface wave absorbing touch on said surface for developing an output signal representative of the degree of absorption of said surface acoustic waves by said touch, said signal having a first wave-timing-related characteristic and a second characteristic indicative of plural discrete non-zero levels of damping or a continuum of levels of damping of said surface acoustic waves propagating on said surface through the region of the touch; and

circuit means responsive to said first characteristic for developing a first signal containing information indicative of the position of the touch, and responsive to said second characteristic for developing a second signal containing information indicative of plural discrete non-zero levels of touch pressure or a continuum of levels of touch pressure.

6. A touch panel system for recognizing touch positions along a predetermined coordinate axis on a touch surface and for responding to touch pressure, comprising:

a substrate having a touch surface capable of propagating surface acoustic waves and being so characterized that a touch on said surface damps the amplitude of a surface wave propagating through the region of the touch;

input surface wave transducer means coupled to said substrate surface for launching a burst of surface waves on said surface;

output surface wave transducer means coupled to said substrate;

surface wave redirecting means for redirecting surface wave burst components derived from said surface wave burst across said surface and to said output transducer means along a plurality of paths of different lengths which are respectively associated with different positions along said coordinate axis on said touch surface; and

circuit means coupled to said input and output transducer means for initiating surface wave bursts on said surface and for detecting touch-induced amplitude damping of received wave burst components, said circuit means developing an output signal having a first wave-timing-related characteristic indicative of which of said plurality of paths was traversed by the touch-damped wave burst component and thus the location of the touch along said coordinate axis of said surface, said output signal having a second characteristic indicative of the touch-pressure-induced damping of said wave burst component propagating on said surface through the region of the touch; and

recognition circuit means receiving said output signal and responsive to said first characteristic for developing a first signal containing information indicative of the position of the touch, and responsive to said second characteristic for developing a second signal containing information indicative of plural discrete non-zero levels of touch pressure or a continuum of levels of touch pressure.

7. A touch panel system for recognizing touch positions along a predetermined coordinate axis on a touch surface and for responding to touch pressure, comprising:

a substrate having a touch surface capable of propagating surface acoustic waves and being so characterized that a touch on said surface damps the amplitude of a surface wave propagating through the region of the touch;

input surface wave transducer means coupled to said substrate surface for launching a burst of surface waves on said surface;

output surface wave transducer means coupled to said substrate;

surface wave redirecting means for redirecting surface wave burst components derived from said surface wave burst across said substrate and to said output transducer means along a plurality of paths of different lengths which are respectively associated with different positions along said coordinate axis on said touch surface; and

circuit means coupled to said input and output transducer means for initiating surface wave bursts on said surface and for detecting touch-induced amplitude damping of received wave burst components, said circuit means developing an output signal having a signal-level-versus-time characteristic with a dip whose location on the time axis is indicative of the transit time of the detected damped wave burst component, and whose depth is indicative of the degree of damping of the detected damped wave burst component,

said circuit means being responsive to the timing of said dip in the signal-level-versus-time characteristic of said output signal for developing a first signal containing information indicative of the location of the touch along said coordinate axis of said surface, said circuit means also being responsive to the depth of said dip for developing a second signal containing information indicative of the level of damping of said surface acoustic waves propagating on said surface through said region of the touch.

8. For use with touch-controllable apparatus, a system for recognizing and utilizing touch actuations of different pressures along a predetermined coordinate axis on a surface associated with said apparatus, comprising:

a substrate having a surface capable of propagating surface acoustic waves and being so characterized that a touch on said surface causes a perturbation of a surface wave propagating through the region of the touch, the magnitude of said perturbation being related to touch pressure;

surface acoustic wave scanning means including input surface wave transducer means coupled to said substrate surface for effecting scanning of said surface with a timed succession of surface acoustic wave bursts directed in a plurality of substantially parallel overlapping paths across said surface transversely to said coordinate axis, each of said plurality of paths being respectively associated with a different position along said coordinate axis on said substrate surface;

output surface wave transducer means coupled to said substrate surface for receiving said bursts of surface waves; and

circuit means coupled to said input and output transducer means for initiating said timed succession of surface wave bursts on said substrate surface and for detecting touch-induced perturbations of received wave bursts, said circuit means including means coupled to said output transducer means for developing an output signal having a first characteristic representative of the timing of a touch perturbed received burst and thus determinative of which of said plurality of paths was traversed by said touch-perturbed wave burst and thereby the location of the touch along said coordinate axis of said substrate surface, said output signal having a second characteristic representative of the magnitude of the perturbation occasioned by the touch pressure-induced perturbation of the waves passing the region of the touch; and

recognition circuit means receiving said output signal and responsive to said first characteristic for developing a first signal containing information indicative of the position of the touch, and responsive to said second characteristic for developing a second signal containing information indicative of plural discrete non-zero levels of touch pressure or a continuum of levels of touch pressure.

9. For use with controllable apparatus, a system for recognizing and locating an intentional perturbation of a surface acoustic wave propagating along one of a multiplicity of paths disposed transverse to a predetermined coordinate axis of a surface associated with said apparatus and for utilizing the magnitude of the perturbation to produce a control effect, said arrangement comprising:

a substrate having a surface capable of propagating surface acoustic waves and being so characterized that a touch on said surface causes a perturbation of a surface wave propagating through the region of the touch, the magnitude of said perturbation being related to touch pressure;

an input transducer coupled to said substrate surface and responsive to an input signal for launching acoustic surface waves along a first path on said surface;

a first reflective grating comprising an array of reflective elements disposed along said first path, with said elements effectively arranged at like angles of incidence to the longitudinal axis of said first path, for extracting from said surface wave a multiplicity of wave components and for directing said wave components across said substrate surface along a like multiplicity of paths each disposed at an angle to said axis of said first path;

an output transducer coupled to said substrate surface at the terminus of a second path on said surface for developing an output signal upon receipt of surface acoustic wave energy;

a second reflective grating comprising an array of reflective elements disposed along said second path and effectively arranged at like angles of incidence to the longitudinal axis of said second path for intercepting said wave components and for redirecting said intercepted wave components a-ong said second path toward said output transducer;

circuit means coupled to said output transducer and responsive to said output signal for identifying a coordinate of the location of said touch induced perturbation; and

detector means also coupled to said output transducer and responsive to a change in a characteristic of said output signal, attributable to said perturbation, for exerting a control effect determined by the magnitude of said perturbation.