Acoustic condition sensor employing a plurality of mutually non-orthogonal waves

• US 6,723,929 B2
• Filed: 06/22/2002
• Issued: 04/20/2004
• Est. Priority Date: 04/19/1995
• Status: Expired due to Fees

• Current Assignee: Elo Touch Solutions, Inc.
• Original Assignee: Elo Touchsystems Incorporated (Elo Touch Solutions, Inc.)
• Inventors: Kent, Joel
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US10/178,692
• Publication Number:
  US 20030164820A1
• Time in Patent Office: 668 Days
• Field of Search: 345/173, 345/177, 178/18.01, 178/18.03, 178/18.04, 178/18.05, 178/18.06, 178/18.07, 178/19.01, 178/19.02, 178/19.03, 178/19.04, 367/907
• US Class Current: 178/18.04
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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: H03K 2217/96011 with propagation, SAW or BAW
• CPC Class Codes: Y10S 367/907 Coordinate determination

Abstract

A touch sensor comprising an acoustic wave transmissive medium having a surface; a plurality of acoustic wave path forming systems, each generating a set of incrementally varying paths through the transmissive medium; and a receiver, receiving signals representing the sets of waves, a portion of each set overlapping temporally or physically by propagating in the transmissive medium along axes which are not orthogonal. The waves may also be of differing wave modes. The receiver system may include a phase, waveform or amplitude sensitive system. Reflective arrays are associated with the medium situated along a path, the path not being a linear segment parallel to a coordinate axis of a substrate in a Cartesian space, a segment parallel to an axial axis or perpendicular to a radial axis of a substrate in a cylindrical space nor parallel and adjacent to a side of a rectangular region of a small solid angle section of a sphere; situated along a path substantially not corresponding to a desired coordinate axis of a touch position output signal; situated along a path substantially non-parallel to an edge of the medium; has a spacing of elements in the array which differs, over at least one portion thereof, from an integral multiple of a wavelength of an incident acoustic wave; has elements in the array which are non-parallel; has an angle of acceptance of acoustic waves which varies over regions of the array; and/or coherently scatter at least two distinguishable acoustic waves which are received by the receiving system.

Claims

1. A touchscreen system, comprising:

a touchscreen substrate, said substrate capable of propagating acoustic waves;

at least one transducer coupled to said substrate, said transducer transducing an acoustic wave propagating along a path in said touchscreen substrate to an electrical signal;

a reflective array pattern comprising a plurality of acoustic wave reflectors coupled to said substrate and disposed along said path, said touchscreen substrate and reflective array pattern having an frequency-dependent acoustic transmission characteristic; and

a controller, coupled to said at least one transducer, for performing an operation selected from one or more of selectively digitally controlling generation of an acoustic wave by said transducer based on said frequency-dependent acoustic transmission characteristic, and selectively receiving an electrical signal from said transducer representing the acoustic wave based on said frequency-dependent acoustic transmission characteristic, and for producing an output corresponding to a detected perturbation of said acoustic wave.

2. The system according to claim 1, wherein said controller automatically determines said frequency-dependent acoustic transmission characteristic.

3. The system according to claim 1, wherein said controller automatically determines said frequency-dependent acoustic transmission characteristic by generating an electrical signal for exciting said at least one transducer to emit an acoustic wave over a range of frequencies, and receiving an electrical signal corresponding to the excited acoustic wave from the transducer.

4. The system according to claim 1, wherein said controller comprises a homodyne receiver.

5. The system according to claim 1, wherein said controller comprises a heterodyne receiver.

6. The system according to claim 1, wherein said controller determines a frequency having a minimum attenuation.

7. The system according to claim 1, wherein said controller determines a frequency having an optimum combination of signal attenuation and parasitic signal characteristics.

8. The system according to claim 1, wherein said controller varies an operating characteristic over time.

9. The system according to claim 1, wherein said controller varies a characteristic of an acoustic wave over a period of emission thereof.

10. The system according to claim 1, wherein said controller implements an adaptive filter for selectively receiving said electrical signal from said transducer.

11. The system according to claim 1, wherein said reflective array pattern has a narrow frequency band pass characteristic, said controller tuning operation to employ acoustic waves having a frequency substantially corresponding to said narrow frequency band.

12. The system according to claim 1, wherein said controller analyzed a received electrical signal for artifacts and produces said output corresponding to a detected perturbation of said acoustic wave filtered of said artifacts.

13. A touchscreen operational method, comprising:

providing a touchscreen substrate, said substrate capable of propagating acoustic waves, and a reflective array pattern comprising a plurality of acoustic wave reflectors coupled to said substrate and disposed along a predefined path, said touchscreen substrate and reflective array pattern having a frequency-dependent acoustic transmission characteristic;

performing an operation selected from one or more of selectively digitally controlling generation of an acoustic wave by said transducer based on said frequency-dependent acoustic transmission characteristic, and selectively receiving an electrical signal from said transducer representing the acoustic wave based on said frequency-dependent acoustic transmission characteristic; and

detecting a perturbation by an external influence of a received acoustic wave.

14. A computer readable medium storing thereon instructions for execution by a general purpose instruction processing computer, for executing the method according to claim 13.