Systems and methods for touch sensing
One embodiment is directed to a system for characterizing interaction between surfaces, comprising: a deformable transmissive layer coupled to an interface membrane, wherein the interface membrane is interfaced against at least one aspect of an interfaced object; a first illumination source operatively coupled to the deformable transmissive layer and configured to emit first illumination light into the deformable transmissive layer at a known first illumination orientation relative to the deformable transmissive layer, such that at least a portion of the first illumination light interacts with the deformable transmissive layer; a detector configured to detect light from within at least a portion of the deformable transmissive layer; and a computing system configured to operate the detector to detect at least a portion of light directed from the deformable transmissive layer, to determine surface orientations pertaining to positions along the interface membrane based at least in part upon interaction of the first illumination light with the deformable transmissive layer, and to utilize the determined surface orientations to characterize a geometric profile of the at least one aspect of the interfaced object as interfaced against the interface membrane.
1. A system for characterizing interaction between surfaces, comprising:
a. a deformable transmissive layer coupled to an interface membrane, wherein the interface membrane is interfaced against at least one aspect of an interfaced object, the deformable transmissive layer comprising an elastomeric composite having a metal oxide pigment material distributed within an elastomeric matrix, the pigment material configured to provide an illumination reflectance which is greater than that of the elastomeric matrix;
b. a first illumination source operatively coupled to the deformable transmissive layer and configured to emit first illumination light into the deformable transmissive layer at a known first illumination orientation relative to the deformable transmissive layer, such that at least a portion of the first illumination light interacts with the deformable transmissive layer;
c. a detector configured to detect light from within at least a portion of the deformable transmissive layer; and
d. a computing system configured to operate the detector to detect at least a portion of light directed from the deformable transmissive layer, to determine surface orientations pertaining to positions along the interface membrane based at least in part upon interaction of the first illumination light with the deformable transmissive layer, and to utilize the determined surface orientations to characterize a geometric profile of the at least one aspect of the interfaced object as interfaced against the interface membrane.
2. The system of claim 1 , wherein the interface membrane is directly coupled between the deformable transmissive layer and the interfaced object.
3. The system of claim 1 , further comprising substantially rigid optical element positioned between the detector and the deformable transmissive layer.
4. The system of claim 3 , wherein the first illumination source is directly coupled to the substantially rigid optical element, and wherein the substantially rigid optical element is configured to distribute the first illumination light to the deformable transmissive layer.
5. The system of claim 3 , wherein the substantially rigid optical element is defined by a bottom surface, a top surface, and one or more sidewall surfaces, wherein the bottom surface is directly coupled to the deformable transmissive layer and the top surface is positioned most proximally adjacent to the detector.
6. The system of claim 5 , wherein the substantially rigid optical element comprises an outer shape substantially similar to one selected from the group consisting of: a cylindrical shape, a cubic shape, and a rectangular prismic shape.
7. The system of claim 5 , wherein the first illumination source is coupled to at least one of the one or more sidewall surfaces of the substantially rigid optical element.
8. The system of claim 1 , further comprising a second illumination source operatively coupled to the deformable transmissive layer and configured to emit second illumination light into the deformable transmissive layer at a known second illumination orientation relative to the deformable transmissive layer, such that at least a portion of the second illumination light interacts with the deformable transmissive layer.
9. The system of claim 8 , wherein the detector is further configured to detect light from within at least a portion of the deformable transmissive layer based upon both the first illumination light and second illumination light, and wherein the computing system is configured to operate the detector to detect at least a portion of the first and second illumination light directed from the deformable transmissive layer, to determine surface orientations pertaining to positions along the interface membrane based at least in part upon interaction of the first and second illumination light with the deformable transmissive layer, and to utilize the determined surface orientations to characterize a geometric profile of the at least one aspect of the interfaced object as interfaced against the interface membrane.
10. The system of claim 8 , wherein the second illumination light and first illumination light have different wavelengths.
11. The system of claim 8 , wherein the second illumination light and first illumination light have different polarization.
12. The system of claim 9 , further comprising a third illumination source operatively coupled to the deformable transmissive layer and configured to emit third illumination light into the deformable transmissive layer at a known third illumination orientation relative to the deformable transmissive layer, such that at least a portion of the third illumination light interacts with the deformable transmissive layer.
13. The system of claim 10 , wherein the detector is further configured to detect light from within at least a portion of the deformable transmissive layer based upon each of the first, second, and third illumination light, and wherein the computing system is configured to operate the detector to detect at least a portion of the first, second, and third illumination light directed from the deformable transmissive layer, to determine surface orientations pertaining to positions along the interface membrane based at least in part upon interaction of the first, second, and third illumination light with the deformable transmissive layer, and to utilize the determined surface orientations to characterize a geometric profile of the at least one aspect of the interfaced object as interfaced against the interface membrane.
14. The system of claim 10 , wherein each of the first, second, and third illumination light have different wavelengths.
15. The system of claim 10 , wherein the first, second, and third illumination light do not all have the same polarization.
16. The system of claim 1 , wherein the first illumination source comprises a light emitting diode.
17. The system of claim 1 , wherein the detector is a photodetector.
18. The system of claim 1 , wherein the detector is an image capture device.
19. The system of claim 18 , wherein the image capture device is a CCD or CMOS device.
20. The system of claim 1 , further comprising a lens operatively coupled between the detector and the deformable transmissive layer.
21. The system of claim 1 , wherein the computing system is operatively coupled to the detector and configured to receive information from the detector pertaining to light detected by the detector from within the deformable transmissive layer.
22. The system of claim 1 , wherein the computing system is operatively coupled to the first illumination source and is configured to control emissions from the first illumination source.
23. The system of claim 1 , wherein the elastomeric material is selected from the group consisting of: silicone, urethane, polyurethane, thermoplastic elastomer (TPE), and thermoplastic polyurethane (TPU).
24. The system of claim 1 , wherein the pigment material comprises a metal oxide selected from the group consisting of: iron oxide, zinc oxide, aluminum oxide, and titanium dioxide.
25. The system of claim 1 , wherein the deformable transmissive layer is bounded by a bottom surface directly coupled to the interface membrane, a top surface most adjacent the detector, and a transmissive layer thickness therebetween, wherein the pigment material is distributed adjacent the bottom surface within the transmissive layer thickness to provide optimized illumination reflectance adjacent the bottom surface.
26. The system of claim 1 , wherein the interface membrane comprises an elastomeric material.
27. The system of claim 1 , wherein the interface member and deformable transmissive layer each have an elastic modulus which is substantially the same.
28. The system of claim 1 , wherein the deformable transmissive layer and interface membrane are directly coupled such that both principal and shear loads applied by the interfaced object are substantially transferred across the interface membrane to the deformable transmissive layer.
29. The system of claim 1 , wherein the deformable transmissive layer comprises a configured to be at least partially filled with a fluid.
30. The system of claim 1 , wherein the interface membrane comprises an assembly of relatively thin and sequentially removable membrane components.