Segmented waveguide core touch sensor systems and methods

• US 9,128,567 B2
• Filed: 11/20/2012
• Issued: 09/08/2015
• Est. Priority Date: 11/20/2012
• Status: Active Grant

• Current Assignee: Elo Touch Solutions, Inc.
• Original Assignee: Elo Touch Solutions, Inc.
• Inventors: Tanaka, Yoshikazu, Kent, Joel C.
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): Ritchie, Darlene M
• Application Number:
  US13/682,621
• Publication Number:
  US 20140139494A1
• Time in Patent Office: 1,022 Days
• Field of Search: 345173-179, 178/18.04, 310/363, 341/34
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate

Abstract

Systems and related methods providing for touch sensors having a waveguide reflective array within a major reflective array are discussed herein. A touch sensor may include a substrate configured to propagate surface acoustic waves. The substrate may include a front surface, a back surface including the reflective arrays, and a connecting surface joining the front surface and the back surface. The reflective arrays may be configured to cause the surface acoustic waves to propagate from the back surface, via the connecting surface, to the front surface. The touch censor may further include circuitry configured to determine a coordinate of a touch event on the front surface based on received attenuations in the surface acoustic waves.

Claims

1. An acoustic touch apparatus, comprising:

a substrate configured to propagate surface acoustic waves, the substrate having;

a front surface;

a back surface; and

a reflective array including array reflector elements configured to redirect at least a portion of the surface acoustic waves, the array reflector elements disposed such that a center-to-center spacing between adjacent array reflector elements defines a distance equal to at least one positive integer multiple of the surface acoustic waves'"'"' wavelength, the array reflector elements including major reflector elements and waveguide reflector elements, the reflective array comprising;

a major reflective array including the major reflector elements, wherein the major reflective array defines a major width dimension; and

a waveguide reflective array including the waveguide reflector elements, wherein;

the waveguide reflective array defines a waveguide width dimension that is smaller than the major width dimension;

at least one of the waveguide reflector elements is disposed between two of the major reflector elements;

the waveguide reflective array defines a waveguide centerline at the middle of the waveguide width dimension; and

the waveguide reflective array is positioned relative to the major reflective array such that the waveguide centerline is within a center third of the major width dimension,

wherein the waveguide reflective array provides a core region to concentrate energy of the surface acoustic waves near the waveguide centerline of the waveguide reflective array and the major reflective array provides a cladding region outside of the core region such that the surface acoustic waves propagate slower in the core region than the cladding region.

2. The acoustic touch apparatus of claim 1, wherein the waveguide centerline is within the middle of the major width dimension.

3. The acoustic touch apparatus of claim 1, wherein the at least one of the waveguide reflector elements has a reflector angle at least substantially parallel to reflector angles of at least one of an adjacent waveguide reflector element and an adjacent reflector element.

4. The acoustic touch apparatus of claim 1, wherein:

the waveguide reflector elements are disposed within regions defined by center-to-center spacing between major reflector elements that are neighboring such that each of the waveguide reflector elements forms a center-to-center interval with at least one of an adjacent waveguide reflector element or an adjacent major reflector element; and

the center-to-center interval is equal to at least one positive integer multiple of the surface acoustic waves'"'"' wavelength.

5. The acoustic touch apparatus of claim 1, wherein at least one of the waveguide reflector elements includes a focusing shape.

6. The acoustic touch apparatus of claim 1, wherein at least one of the major reflector elements includes a focusing shape.

7. The acoustic touch apparatus of claim 1, wherein:

the waveguide reflective array further includes semi-major reflector elements that are staggered relative to each other; and

the major reflective array and the waveguide reflective array comprise and are defined by the two or more semi-major reflector elements.

8. The acoustic touch apparatus of claim 1, wherein at least two of the major reflector elements are neighboring and are substantially parallel to each other.

9. The acoustic touch apparatus of claim 1 further comprising a transmitting transducer configured to generate and propagate the surface acoustic waves in a prevailing direction along the major reflective array and the waveguide reflective array and wherein:

the substrate includes a curved connecting surface joining the front surface and the back surface;

the transmitting transducer is coupled to the back surface; and

the reflective array is configured to cause the surface acoustic waves to propagate from the back surface, via the connecting surface, and to the front surface; and

wherein the major reflector elements are disposed such that;

center-to-center spacings between major reflector elements that are neighboring have a distance equal to positive integer multiples of the surface acoustic waves'"'"' wavelength; and

the center-to-center spacings between the major reflector elements that are neighboring are comparatively greater at a first portion of the major reflective array closer to the transmitting transducer and smaller at a second portion of the major reflective array farther from the transmitting transducer.

10. The acoustic touch apparatus of claim 1, further comprising a receiving transducer configured to receive the surface acoustic waves propagating in a prevailing direction along the major reflective array and the waveguide reflective array and wherein:

the substrate includes a curved connecting surface joining the front surface and the back surface;

the receiving transducer is coupled to the back surface; and

the reflective array is configured to cause the surface acoustic waves to propagate to the receiving transducer; and

wherein the major reflector elements are disposed such that;

center-to-center spacings between major reflector elements that are neighboring have a distance equal to positive integer multiples of the surface acoustic waves'"'"' wavelength; and

the center-to-center spacings between the major reflector elements that are neighboring are comparatively smaller at a first portion of the major reflective array further from the acoustic wave transducer and larger at a second portion of the major reflective array closer to the acoustic wave transducer.

11. The acoustic touch apparatus of claim 1, wherein:

the substrate includes at least one border region along an edge of the back surface of the substrate; and

the reflective array is disposed at the border region.

12. The acoustic touch apparatus of claim 1, further comprising a display device positioned such that the display device is visible through the front surface of the substrate, and wherein:

the back surface of the substrate is mechanically bonded to the display device via an acoustically absorptive bonding layer; and

the waveguide reflective array is configured to concentrate energy of surface acoustic waves propagating along the reflective array away from the acoustically absorptive bonding layer.

13. A method for manufacturing an acoustic touch apparatus, comprising:

providing a substrate configured to propagate surface acoustic waves, the substrate having;

a front surface;

a back surface; and

a connecting surface joining the front surface and the back surface;

positioning a mask including open spaces to the back surface of the substrate, wherein the open spaces define a reflective array including array reflector elements disposed such that a center- to-center spacing between adjacent array reflector elements defines a distance equal to at least one positive integer multiple of the surface acoustic waves'"'"' wavelength, the array reflector elements including major reflector elements and waveguide reflector elements, the reflective array including a major reflective array and a waveguide reflective array, wherein;

the major reflective array includes the major reflective elements;

the major reflective array defines a major width dimension;

the waveguide reflective array includes the waveguide reflector elements;

the waveguide reflective array defines a waveguide width dimension that is smaller than the major width dimension;

at least one of the waveguide reflector elements is disposed between two of the major reflector elements;

the waveguide reflective array defines a waveguide centerline at the middle of the waveguide width dimension; and

the waveguide reflective array is positioned relative to the major reflective array such that the waveguide centerline is within a center third of the major width dimension,

wherein the waveguide reflective array provides a core region to concentrate energy of the surface acoustic waves near the waveguide centerline of the waveguide reflective array and the major reflective array provides a cladding region outside of the core region such that the surface acoustic waves propagate slower in the core region than the cladding region;

applying an acoustically reflective material to the substrate such that the acoustically reflective material is disposed on the back surface in the open spaces; and

curing the substrate including the acoustically reflective material.

14. The method of claim 13, further comprising defining the mask such that the waveguide centerline is within the middle of the major width dimension.

15. The method of claim 13, further comprising defining the mask such that the least one of the waveguide reflector elements has a reflector angle at least substantially parallel to reflector angles of at least one of an adjacent waveguide reflector element and an adjacent major reflector element.

16. The method of claim 15, further comprising defining the mask such that at least one of the waveguide reflector elements, at least one of the major reflector elements, or both include a focusing shape.

17. The method of claim 13, further comprising defining the mask such that:

the waveguide reflector elements are disposed within regions defined by center-to-center spacing between neighboring major reflector elements such that each of the waveguide reflector elements forms a center-to-center interval with at least one of an adjacent waveguide reflector element or an adjacent major reflector element; and

the center-to-center interval is equal to at least one positive integer multiple of the surface acoustic waves'"'"' wavelength.

18. An acoustic touch apparatus prepared by a process, comprising:

providing a substrate configured to propagate surface acoustic waves, the substrate having;

a front surface;

a back surface; and

a connecting surface joining the from surface and the back surface;

positioning a mask including open spaces to the back surface of the substrate, wherein the open spaces define a reflective array including array reflector elements disposed such that a center-to-center spacing between adjacent array reflector elements defines a distance equal to at least one positive integer multiple of the surface acoustic waves'"'"' wavelength, the array reflector elements including major reflector elements and waveguide reflector elements, the reflective array including a major reflective array and a waveguide reflective array, wherein;

the major reflective array includes the major reflective elements;

the major reflective array defines a major width dimension;

the waveguide reflective array includes the waveguide reflector elements;

the waveguide reflective array defines a waveguide width dimension that is smaller than the major width dimension;

at least one of the waveguide reflector elements is disposed between two of the major reflector elements;

the waveguide reflective array defines a waveguide centerline at the middle of the waveguide width dimension; and

the waveguide reflective array is positioned relative to the major reflective array such that the waveguide centerline is within a center third of the major width dimension,

wherein the waveguide reflective array provides a core region to concentrate energy of the surface acoustic waves near the waveguide centerline of the waveguide reflective array and the major reflective array provides a cladding region outside of the core region such that the surface acoustic waves propagate slower in the core region than the cladding region;

applying an acoustically reflective material to the substrate such that a glass frit is disposed on the back surface in the open spaces; and

curing the substrate including the acoustically reflective material.