ACOUSTIC TOUCH APPARATUS WITH ADDRESSABLE MULTI-TOUCH CAPABILITY

• US 20140118307A1
• Filed: 10/30/2012
• Published: 05/01/2014
• Est. Priority Date: 10/30/2012
• Status: Active Grant

• Current Assignee: Elo Touch Solutions, Inc.
• Original Assignee: Elo Touch Solutions, Inc.
• Inventors: Kent, Joel, Berget, Damien
• Granted Patent: US 8,994,696 B2
• Time in Patent Office: Days
• US Class Current: 345/177
• CPC Class Codes: G06F 3/0433 in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate
• CPC Class Codes: H03H 9/02535 of surface acoustic wave devices

Abstract

An acoustic touch apparatus (100) that utilizes the transfer of surface acoustic waves from one surface (115), through the touch substrate (105), to another surface (110) and a grid of sensitivity zones (Z) formed on one of the surfaces (115) to enable multi-touch capabilities.

Claims

1. An acoustic touch apparatus that distinguishes simultaneous touches in a touch region, comprising a substrate that has two opposite surfaces and that is adapted to propagate surface acoustic waves along each opposite surface;

a transmitting element that is adapted to transmit propagating surface acoustic waves for each opposite surface; and

a receiving element that is adapted to receive the propagating surface acoustic waves for each opposite surface, one of said opposite surfaces having the touch region defined thereon and said substrate being adapted to transfer, through the substrate, surface acoustic waves between the opposite surfaces so as to alternate in the touch region the propagating surface acoustic waves from each opposite surface.

2. The apparatus of claim 1, wherein the transmitting element comprises an acoustic transducer that generates propagating surface acoustic waves and a reflector array that reflects the generated propagating surface acoustic waves onto each opposite surface, and the receiving element comprises a reflector array that reflects surface acoustic waves propagating on each opposite surface and an acoustic transducer that receives the reflected propagating surface acoustic waves.

3. The apparatus of claim 1, wherein said touch region provides signal information for each touch to the receiving element so that the apparatus may determine positional information of a respective touch on said touch region, said signal information being based on signal perturbations of each of the alternating propagating surface acoustic waves induced by a respective touch.

4. The apparatus of claim 3, wherein said signal information comprises a comparison of signal attenuations of the alternating propagating surface acoustic waves induced by a respective touch.

5. The apparatus of claim 3, wherein said signal information comprises a comparison of the powers of signal attenuations of the alternating propagating surface acoustic waves induced by a respective touch.

6. The apparatus of claim 1, wherein said touch region is adapted to form first probable zones of touch contact by the propagating surface acoustic waves from one opposite surface and second probable zones of touch contact by the propagating surface acoustic waves from the other opposite surface, said first and second probable zones being alternately formed between the transmitting element and the receiving element.

7. The apparatus of claim 6, wherein said first and second probable zones of touch contact provide respective signal information for each touch to the receiving element that distinguish between simultaneous touches on respective locations of said first and second probable zones, said signal information based on signal perturbations of each of the alternating propagating surface acoustic waves induced by a respective touch.

8. The apparatus of claim 7, wherein said signal information comprises a comparison of signal attenuations of the alternating propagating surface acoustic waves induced by a respective touch.

9. The apparatus of claim 7, wherein said signal information comprises a comparison of the powers of signal attenuations of the alternating propagating surface acoustic waves induced by a respective touch.

10. The apparatus of claim 6, wherein said apparatus further comprises a transmitting element and an associated receiving element for each axis coordinate of the touch region, said touch region being adapted to form first and second probable zones of touch contact for each axis coordinate.

11. The apparatus of claim 10, wherein a respective probable zone of touch contact for a first axis coordinate provides signal information for each touch that distinguishes between simultaneous touches on different locations of a respective probable zone of touch contact for a second axis coordinate.

12. An acoustic touch sensor system, comprising:

a substrate having a top surface, a bottom surface, and a curved connecting surface formed between said top surface and said bottom surface, said substrate being adapted in a peripheral region to propagating surface acoustic waves along substrate surfaces and in a central region to permit the transfer, through the substrate, of surface acoustic waves between the top and the bottom surfaces;

a first transmitting element disposed on the peripheral region of the bottom surface;

a first receiving element disposed on the peripheral region of the bottom surface, the transmitting element and the receiving element disposed on opposite sides of the central region; and

a controller that excites the first transmitting element to generate propagating surface acoustic waves and that analyzes the propagating surface acoustic waves received by the first receiving element to determine coordinate information of a touch in the central region on the top surface, said first transmitting element being adapted to generate propagating surface acoustic waves in a first direction toward the central region and in a second direction toward a proximate curved connecting surface and said first receiving element being adapted to receive propagating surface acoustic waves from the central region and from a proximate curved connecting surface and said substrate forming in the central region a wave propagation path that oscillates a respective propagating surface acoustic wave between the top surface and the bottom surface.

13. The system of claim 12, wherein the first transmitting element comprises a first transmitting acoustic wave transducer disposed on the peripheral region on one side of the substrate, a second transmitting acoustic wave transducer disposed on the peripheral region on an opposite side of the substrate, and a transmitting reflective array that is disposed on the peripheral region between the first and second transmitting acoustic wave transducers and is adapted to reflect generated propagating surface acoustic waves in a first direction toward the central region and in a second direction toward a proximate curved connecting surface, and the first receiving element comprises a first receiving acoustic wave transducer disposed on the peripheral region on one side of the substrate, a second receiving acoustic wave transducer disposed on the peripheral region on an opposite side of the substrate, and a receiving reflective array that is disposed on the peripheral region between the first and second receiving acoustic wave transducers and is adapted to receive propagating surface acoustic waves from the central region and from a proximate curved connecting surface.

14. The system of claim 12, further comprising a second transmitting element and a second receiving element disposed on the other two opposing sides of the central region of the substrate in a similar manner as the respective first transmitting and receiving elements, each pair of elements being utilized to define a respective axis coordinate of the central region on the top surface.

15. The system of claim 13, wherein the transmitting reflective array and the receiving reflective array each comprise a plurality of segments that are each configured to have reflector elements facing in the opposite direction from the respective reflector elements of the preceding and the succeeding segment.

16. The system of claim 15, wherein the plurality of segments of the transmitting reflective array and the receiving reflective array are each disposed in a non-overlapping zigzag manner between the respective transducers.

17. The system of claim 15, wherein the plurality of segments of the transmitting reflective array and the receiving reflective array are each disposed in an overlapping zigzag manner between the respective transducers.

18. The system of claim 13, wherein the transmitting reflective array and the receiving reflective array each comprise at least two sets of segments that are disposed proximate one another, each segment being configured to have reflector elements facing in the opposite direction from the respective reflector elements of the preceding and the succeeding segment in a respective set, and each set being tuned to a different one of a plurality of frequencies of surface acoustic waves generated by the transmitting acoustic wave transducers.

19. The system of claim 18, wherein each set of segments is disposed in a non-overlappping manner between the respective transducers and the two sets of segments are disposed in an interlocking manner with one another.

20. The system of claim 12, wherein the peripheral region is adapted to suppress the transfer, through the substrate, of surface acoustic waves between the top and the bottom surfaces.

21. The system of claim 13, wherein the transmitting and receiving reflective arrays are constant density arrays and the controller equalizes the energy distribution of the propagating surface acoustic waves.

22. The system of claim 13, wherein the transmitting reflective arrays are constant density arrays and the receiving reflective arrays have varying reflector density that compensate for differences in energy density of the propagating surface acoustic waves.

23. The system of claim 22, wherein receiving reflective arrays of lesser reflector density receive propagating surface acoustic waves of higher energy density and receiving reflective arrays of higher reflector density receive propagating surface acoustic waves of lower energy density.

24. The system of claim 13, wherein the controller analyzes the ratio of signal attenuations between the surface acoustic waves propagating in the first and second directions and the power of attenuation of each wave to determine coordinate information of a touch.

25. The system of claim 13, wherein the transmitting element generates the surface acoustic waves propagating in the first and second directions in an out-of-phase relationship and the controller analyzes the power of attenuation of each wave to determine coordinate information of a touch.

26. An acoustic touch sensor system having multi-touch capability, comprising:

a substrate adapted to propagate surface acoustic waves along opposite surfaces and to transfer, through the substrate, surface acoustic waves between the surfaces and to form a touch sensitivity pattern on a touch region on one of the opposite surfaces based on the alternating surface acoustic waves propagating through the touch region;

a transmitter-reflector arrangement adapted to transmit surface acoustic waves on each opposite surface;

a receiver-reflector arrangement adapted to receive surface acoustic waves from each opposite surface and to produce a touch response signal in response to a touch on the touch region; and

a controller that operates on the touch response signals and determines positional information of the touch on the touch region from the touch response signals.

27. The system of claim 26, wherein the touch sensitivity pattern defines a probable zone of touch for each alternating surface acoustic wave propagating through the touch region that permits the controller to distinguish between touches in different zones and between touches in different touch region locations of the same zone.

28. An acoustic touch sensor system, comprising:

a substrate having a first surface with a touch region and a second surface opposite the first surface, the substrate being adapted to propagate surface acoustic waves along each of the surfaces and to transfer, through the substrate, surface acoustic waves between the surfaces;

a transmitter adapted to transmit respective surface acoustic waves on each surface that alternate propagating in the touch region as the surface acoustic waves transfer between the surfaces;

a receiver adapted to receive surface acoustic waves from each surface and to produce touch response signals in response to a touch on the touch region; and

a controller that operates on the touch response signals and determines positional information of a respective touch on the touch region from the touch response signals.

29. The system of claim 28, wherein the controller determines a first positional coordinate of the touch on the touch region based on delay time measurements of received surface acoustic waves and a second positional coordinate, orthogonal to the first positional coordinate, based on perturbation measurements of the alternating propagating surface acoustic waves.

30. The system of claim 28, wherein the controller determines a positional coordinate of the touch on the touch region, relative to the transmitter position, based on perturbation measurements of the alternating propagating surface acoustic waves.

31. The system of claim 28, wherein the controller measures, for each of a plurality of transmitting frequencies, perturbations of the alternating propagating surface acoustic waves in response to the touch on the touch region to determine a positional coordinate of the touch on the touch region relative to the transmitter position, a respective positional coordinate being identified with a specific pattern of measurements across the plurality of transmitting frequencies.

32. The system of claim 28, wherein the transmitter is adapted to transmit over a range of transmitting frequencies, an alternating propagation pattern being formed in the touch region for a respective transmitting frequency in the range, and the controller is adapted to correspond a touch position on the touch region with a respective sequence of coded values derived from the alternating propagation patterns formed in the touch region for a plurality of transmitting frequencies in the range.

33. The system of claim 32, wherein a coded value for a respective alternating propagation pattern represents whether the surface acoustic wave transmitted on the first surface or the surface acoustic wave transmitted on the second surface is more touch sensitive at a respective touch position in the touch region.

34. The system of claim 32, wherein a coded value for a respective alternating propagation pattern represents a function of the ratio of a touch-induced perturbation of the surface acoustic wave transmitted on the first surface to a touch-induced perturbation of the surface acoustic wave transmitted on the second surface at a respective touch position in the touch region.

35. The system of claim 34, wherein the coded values for a respective alternating propagation pattern across touch positions in the touch region form a continuous curve of ratio functions.

36. The system of claim 28, wherein the transmitter is adapted to transmit in tone bursts of finite duration for a respective excitation frequency of the transmitter and the controller is adapted to undertake digital signal processing of the touch response signals and non-touch response signals provided by the receiver to obtain perturbation information of the alternating propagating surface acoustic waves.

37. The system of claim 28, wherein said system further comprises a transmitter and an associated receiver for each axis coordinate of the touch region and wherein the controller determines a first axis coordinate of the touch on the touch region based on perturbation measurements of the alternating propagating surface acoustic waves transmitted and received in the first axis coordinate direction and a second axis coordinate of the touch on the touch region based on perturbation measurements of the alternating propagating surface acoustic waves transmitted and received in the second axis coordinate direction.