Document processor with optical sensor arrangement
View Patent ↗An apparatus for document processing comprises an optical sensor including a light source, a light detector and an optical element. The optical sensor is adapted so that, during operation of the apparatus, at least a first portion of light from the source that enters the optical element travels along paths in the optical element so as to be re-directed by total internal reflection toward the detector and wherein the total internal reflection is maintained when the optical element is wet. Signals form the optical sensor may be used to determine, for example, the state of a document storage cassette or the location of a document with respect to the cassette.
1. An apparatus comprising a document processor, wherein the document processor comprises a banknote validator, an optical sensor including a light source, a light detector and an optical element, wherein the optical sensor is adapted so that, during operation, at least a first portion of light from the source that enters the optical element travels along paths in the optical element so as to be re-directed by total internal reflection toward the detector and wherein the total internal reflection is maintained when the light path encounters a surface of the optical element that is wet.
2. The apparatus of claim 1 wherein the light source comprises a light emitting diode.
3. The apparatus of claim 1 wherein the optical element comprises a prism light-pipe structure.
4. The apparatus of claim 3 wherein the prism light-pipe is composed of polycarbonate.
5. The apparatus of claim 3 wherein the optical element comprises a faceted prism structure including a plurality of facets.
6. The apparatus of claim 5 wherein the optical element comprises at least four facets for redirecting light from the light source toward the light detector by total internal reflection.
7. The apparatus of claim 1 wherein the optical element comprises a smoothly curving three-dimensional toroidal light-pipe structure.
8. An apparatus for document processing comprising an optical sensor, a document acceptor portion, and a transport system to move a document into a document storage cassette coupled to the document acceptor portion, the optical sensor including a light source, a light detector and an optical element, wherein the optical sensor is adapted so that, during operation, at least a first portion of light from the source that enters the optical element travels along paths in the optical element so as to be re-directed by total internal reflection toward the detector and wherein the total internal reflection is maintained when the light path encounters a surface of the optical element that is wet.
9. The apparatus of claim 8 wherein the acceptor portion houses the light source and light detector, and wherein the optical element is located such that, during operation of the apparatus, if the document is being pushed into the cassette, the document at least partially blocks light from the optical element that is directed toward the detector.
10. The apparatus of claim 9 wherein the optical element is located adjacent to a slot adapted for the document to pass through from the acceptor portion to the document storage cassette.
11. The apparatus of claim 9 wherein the light source comprises a light emitting diode.
12. The apparatus of claim 9 wherein the optical element comprises a prism light-pipe structure.
13. The apparatus of claim 9 wherein the optical element comprises a faceted prism structure including a plurality of facets.
14. The apparatus of claim 9 wherein the optical element comprises a smoothly curving three-dimensional toroidal light-pipe structure.
15. The apparatus of claim 8 wherein the acceptor portion includes a microcontroller adapted to process signals from the light detector to determine a position of the document with respect to the cassette.
16. The apparatus of claim 15 wherein the microcontroller is adapted to determine, based on signals from the detector, whether the document is being pushed into the cassette for storage therein.
17. The apparatus of claim 16 wherein the microcontroller is adapted to determine, based on signals from the detector, whether the document has completely passed into the cassette.
18. An apparatus for document processing comprising:
an acceptor portion housing a light source and a light detector;
a document storage cassette including a pusher plate with a reflective portion, and
an optical element,
wherein the light source, light detector and optical element are arranged so that, during operation, a first portion of light from the light source that enters the optical element travels along paths in the optical element so as to be re-directed by total internal reflection toward the light detector and wherein the total internal reflection is maintained when the light path encounters a surface of the optical element that is wet, and
wherein, during operation, a second portion of the light that enters the optical element passes through the optical element and is reflected by the reflective portion of the pusher plate toward the detector, wherein an amount of light reflected by the reflective portion toward the detector depends on a position of the pusher plate in the cassette.
19. The apparatus of claim 18 adapted so that, during operation, a document being pushed into the cassette from the acceptor portion at least partially blocks some light from the optical element toward the detector.
20. The apparatus of claim 19 wherein the optical element is located adjacent to a slot adapted for the document to pass through from the acceptor portion to the cassette.
21. The apparatus of claim 18 wherein the reflective portion is adjacent an edge of the pusher plate.
22. The apparatus of claim 18 wherein the reflective portion campuses a reflective foil.
23. The apparatus of claim 22 wherein the acceptor portion includes a microcontroller adapted to process signals from the light detector to determine a position of a document with respect to the cassette.
24. The apparatus of claim 23 wherein the microcontroller is adapted to determine based on signals from the detector whether the document is being pushed into the cassette for storage therein.
25. The apparatus of claim 24 wherein the microcontroller is adapted to determine based on signals from the detector whether the document has completely passed into the cassette.
26. The apparatus of claim 23 wherein the microcontroller is adapted to determine the position of the pusher plate in the cassette based on signals from the detector.
27. The apparatus of claim 23 wherein the microcontroller is adapted to use signals from the detector to determine whether the cassette is full.
28. The apparatus of claim 23 wherein the reflective portion is adapted so that, during operation, it reflects less light back toward the detector when the cassette is filled, compared to an amount of light it reflects back toward the detector when the cassette is not full.
29. The apparatus of claim 18 wherein the optical element comprises a prism light-pipe structure.
30. The apparatus of claim 29 wherein the prism light-pipe is composed of polycarbonate.
31. The apparatus of claim 18 wherein the optical element comprises a faceted prism structure including a plurality of facets.
32. The apparatus of claim 31 wherein the optical element comprises at least four facets for redirecting light from the light source toward the light detector by total internal reflection.
33. The apparatus of claim 18 wherein the optical element comprises a smoothly curving three-dimensional toroidal light-pipe structure.
34. The apparatus of claim 33 wherein the optical element includes a web structure adapted so that, during operation of the apparatus, the second portion of light is leaked through the optical element via the web structure.
35. The apparatus of claim 34 wherein the web structure is composed of polycarbonate.
36. The apparatus of claim 18 wherein the acceptor portion comprises a banknote validator.
37. An apparatus comprising a document processor, wherein the document processor comprises a bill acceptor, an optical sensor including a light source, a light detector and an optical element, wherein the optical sensor is adapted so that, during operation, at least a first portion of light from the source that enters the optical element travels along paths in the optical element so as to be re-directed by total internal reflection toward the detector and wherein the total internal reflection is maintained when the light path encounters a surface of the optical element that is wet.