Acoustic touch apparatus
View Patent ↗An improved acoustic touch apparatus that has a logo or application icon applied on the back surface of a propagating substrate which can be viewed through the substrate and an acoustic element situated adjacent the logo or application icon that can compensate for phase velocity shifts of surface acoustic waves in propagating over the logo or application icon.
1. An acoustic touch apparatus, comprising:
a substrate having surfaces configured to propagate surface acoustic waves;
at least one acoustic wave transducer on a first surface; and
at least one reflective array on the first surface, said transducer configured to at least transmit or receive surface acoustic waves to or from the reflective array and said reflective array configured to acoustically couple surface acoustic waves to propagate between surfaces of the substrate, and said substrate having a first acoustic element disposed on the first surface that is configured to intercept propagating surface acoustic waves on the first surface and is configured to cause variations in the phase velocity of the propagating surface acoustic waves and a second acoustic element disposed on the first surface to equalize the variations, wherein the first acoustic element comprises an applied material of a logo or an icon.
2. The apparatus of claim 1 , wherein the second acoustic element is configured to cancel out the phase advance or delay of any portion of the propagating surface acoustic waves intercepted by the first acoustic element.
3. The apparatus of claim 1 , wherein the second acoustic element is disposed on the first surface in proximity to the first acoustic element.
4. The apparatus of claim 1 , wherein the second acoustic element is disposed on the first surface as physically close as possible to the first acoustic element.
5. The apparatus of claim 1 , wherein the second acoustic element is configured to intercept propagating surface acoustic waves intercepted by the first acoustic element.
6. The apparatus of claim 5 , wherein the second acoustic element is configured to intercept propagating surface acoustic waves parallel to the propagating surface acoustic waves intercepted by the first acoustic element.
7. The apparatus of claim 1 , wherein the first acoustic element comprises a patch of acoustic material applied over a cut-out of a layer of acoustically benign material applied along a border of the first surface.
8. The apparatus of claim 7 , wherein the layer of acoustically benign material comprises a first opaque ink and the patch of acoustic material comprises a second opaque ink having different visual properties than the first opaque ink.
9. The apparatus of claim 1 , wherein the first acoustic element comprises and an acoustic material filling a cut-out of a layer of acoustically benign material applied along a border of the first surface, said first and second materials being visually distinguished from one another.
10. The apparatus of claim 1 , wherein the first acoustic element comprises acoustic material applied on the first surface and disposed under a layer of acoustically benign material applied along a border of the first surface.
11. The apparatus of claim 10 , wherein the layer of acoustically benign material comprises a first opaque ink and the acoustic material of the first acoustic element comprises a second opaque ink having different visual properties than the first opaque ink.
12. The apparatus of claim 7 , wherein the second acoustic element comprises acoustic material disposed adjacent the cut-out over the layer of acoustically benign material applied along the border of the first surface and either over or under the patch.
13. The apparatus of claim 7 , wherein the second acoustic element comprises acoustic material disposed on the patch over the cut-out.
14. The apparatus of claim 10 , wherein the second acoustic element comprises acoustic material disposed adjacent the first acoustic element and either over or under the layer of acoustically benign material applied along the border of the first surface.
15. The apparatus of claim 13 , wherein the second acoustic element comprises acoustic material that has the same form as the cut-out and is disposed on the patch so as to be superimposed on the cut-out.
16. The apparatus of claim 15 , wherein the superimposed acoustic material is aligned with the cut-out within a fraction of the wavelength of the propagating surface acoustic waves.
17. The apparatus of claim 12 , wherein the reflective array is disposed over the layer of acoustically benign material along the border of the first surface; the cut-out and the patch of the first acoustic element; and the second acoustic element, said propagating surface acoustic waves intercepted by the first acoustic element comprising a portion of the surface acoustic waves that interact with the reflective array.
18. The apparatus of claim 14 , wherein the reflective array is disposed over the layer of acoustically benign material along the border of the first surface; the first acoustic element; and the second acoustic element, said propagating surface acoustic waves intercepted by the first acoustic element comprising a portion of the surface acoustic waves that interact with the reflective array.
19. The apparatus of claim 12 , wherein the cut-out comprises a plurality of shapes and the second acoustic element is formed with a shape that is a composite of the plurality of the shapes of the cut-out.
20. The apparatus of claim 14 , wherein the first acoustic element comprises a plurality of shapes and the second acoustic element is formed with a shape that is a composite of the plurality of the shapes of the first acoustic element.
21. The apparatus of claim 12 , wherein the cut-out comprises a plurality of separated shapes and the second acoustic element comprises a plurality of separated segments that are interspersed among the shapes, each segment disposed adjacent a respective shape and at least configured to partially intercept the propagating surface acoustic waves intercepted by the respective shape.
22. The apparatus of claim 14 , wherein the first acoustic element comprises a plurality of separated shapes and the second acoustic element comprises a plurality of separated segments that are interspersed with the shapes, each segment disposed adjacent a respective shape and at least configured to partially intercept a portion of the propagating surface acoustic waves that are parallel to the propagating surface acoustic waves intercepted by the respective shape.
23. The apparatus of claim 7 , wherein the second acoustic element comprises an extension of the patch disposed over the layer of acoustically benign material that intercepts at least a portion of the propagating surface acoustic waves that are parallel to the propagating surface acoustic waves intercepted by the patch.
24. The apparatus of claim 23 , wherein the extension of the patch comprises a first portion that intercepts surface acoustic waves traveling in a first direction and a second portion that intercepts surface acoustic waves traveling in a second direction perpendicular to the first direction.
25. The apparatus of claim 23 , wherein the extension of the patch comprises either a layer of glass frit or a layer of glass frit disposed on a layer of acoustic material which is the same as the patch acoustic material applied over the cut-out.
26. The apparatus of claim 7 , wherein the reflective array is disposed over the layer of acoustically benign material along the border of the first surface and at least a portion of the cut-out and the patch of the first acoustic element, said propagating surface acoustic waves intercepted by the first acoustic element comprising a portion of the surface acoustic waves that interact with the reflective array, and the second acoustic element comprises the portion of the reflective array disposed over the cut-out and the patch, said portion having a higher density of reflector elements than the remainder of the reflective array.
27. The apparatus of claim 26 , wherein the higher density maintains reflector element spacing equal to an integral multiple of the surface acoustic wave wavelength transmitted by the transducer.
28. The apparatus of claim 26 , wherein the higher density obtains a desired phase velocity of the surface acoustic waves transmitted by the transducer.
29. The apparatus of claim 5 , wherein the second acoustic element counteracts the phase advance of any portion of the propagating surface acoustic waves intercepted by the first acoustic element.
30. The apparatus of claim 6 , wherein the second acoustic element counteracts the phase advance of a portion of the propagating surface acoustic waves parallel to the propagating surface acoustic waves intercepted by the first acoustic element.