Claims
- 1. A document acceptor comprising:
- a document transport path;
- an optical sensor disposed adjacent the transport path, wherein the optical sensor includes at least first and second light emitting devices and an optical receiver, wherein the optical receiver receives optical signals originating from the first light emitting device when the sensor is operated in a first mode, and wherein the optical receiver receives optical signals originating from the second light emitting device when the sensor is operated in a second mode; and
- a controller for controlling the sensor to operate in at least either the first mode or the second mode and for processing signals based on an output from the sensor, wherein when the sensor is operated in the first mode electrical signals originating from the optical receiver are used to determine an absence or presence of the document at a position along the path, and wherein when the sensor is operated in the second mode electrical signals originating from the optical receiver are indicative of whether the document includes a predetermined pattern.
- 2. The acceptor of claim 1 wherein the second light emitting device and the optical receiver are disposed on a first side of the document transport path and are configured so that when the sensor is operated in the second mode and a document travels along the path in a vicinity of the sensor, optical signals originating from the second light emitting device are reflected by the document and sensed by the optical receiver.
- 3. The acceptor of claim 2 wherein the second light emitting device is inclined at an angle with respect to the document transport path.
- 4. The acceptor of claim 1 further including a prism, wherein the optical receiver and the first light emitting device are disposed on a first side of the document transport path, the prism is disposed on a second side of the path, and wherein the first light emitting device, the prism and the optical receiver are configured so that when the sensor is operated in the first mode, optical signals originating from the first light emitting device are transmitted across the document transport path, reflected by the prism and sensed by the optical receiver.
- 5. The acceptor of claim 4 wherein the prism includes a trapezoidal shaped cross section.
- 6. The acceptor of claim 1 wherein the first and second light emitting devices emit light at different wavelengths from one another.
- 7. The acceptor of claim 6 wherein the first light emitting device emits red light and the second light emitting device emits infrared light.
- 8. The acceptor of claim 1 further including a prism, wherein the optical receiver and the first and second light emitting devices are disposed on a first side of the document transport path, wherein the prism is disposed on a second side of the path, and wherein the light emitting devices, the prism and the optical receiver are configured so that when the sensor is operated in the first mode, optical signals originating from the first light emitting device are transmitted across the document transport path, reflected by the prism and sensed by the optical receiver, and when the sensor is operated in the second mode and a document travels along the path in a vicinity of the sensor, optical signals originating from the second light emitting device are reflected by the document and sensed by the optical receiver.
- 9. The acceptor of claim 1 wherein when the sensor is operated in the first mode, the controller uses electrical signals originating at the optical receiver to sense an edge of the document.
- 10. The acceptor of claim 9 wherein when the sensor is operated in the first mode, the controller uses electrical signals originating at the optical receiver to sense a leading edge of the document.
- 11. The acceptor of claim 9 wherein when the sensor is operated in the first mode, the controller uses electrical signals originating at the optical receiver to sense a trailing edge of the document.
- 12. The acceptor of claim 1 wherein when the sensor is operated in the first mode, an amplitude of light emitted by the first light emitting device saturates the optical receiver in the absence of a document intersecting an optical path from the first light emitting device to the optical receiver.
- 13. The acceptor of claim 12 wherein when the sensor is operated in the first mode and a document intersects the optical path from the first light emitting device to the optical receiver, the sensor is no longer saturated.
- 14. The acceptor of claim 1 wherein when the sensor is operated in the first mode, the second light emitting device does not emit light.
- 15. The acceptor of claim 1 wherein when the sensor is operated in the second mode, the first light emitting device does not emit light.
- 16. The acceptor of claim 1 further including:
- circuitry for selectively controlling either the first or the second light emitting devices to emit light at an amplitude in response to control signals from the controller, wherein the circuitry includes a sample and hold circuit coupled to the second light emitting device.
- 17. The acceptor of claim 16 further including a digital-to-analog converter having inputs coupled to the controller, and having an output coupled to the sample and hold circuit when the second light emitting device is selected to emit light, wherein signals provided to the digital-to-analog converter by the controller control the amplitude of light to be emitted by the second light emitting device.
- 18. The acceptor of claim 1 further including:
- pattern discrimination circuitry coupled to the controller for processing electrical signals originating at the optical receiver when the sensor is operated in the second mode.
- 19. The acceptor of claim 18 wherein the pattern discrimination circuitry converts amplitude changes in an electrical signal originating at the optical receiver to one or more pulses.
- 20. The acceptor of claim 19 wherein the pattern discrimination circuitry includes a clocked differentiator.
- 21. The acceptor of claim 19 wherein the pulses correspond to transitions in a pattern on a document travelling along the document transport path.
- 22. The acceptor of claim 21 wherein the pattern on the document is a bar-code pattern.
- 23. The acceptor of claim 19 further including a closed-loop feedback circuit for sampling analog output signals from the optical receiver, wherein the controller uses the sampled signals to adjust a brightness of the second light emitting device when the sensor is operated in the second mode.
- 24. The acceptor of claim 1 further including a document storage location and an entryway, wherein the controller can control the optical sensor to operate in a third mode in which the optical receiver receives optical signals from the first light emitting device, and wherein when the sensor is operated in the third mode electrical signals from the optical receiver are used to determine whether the document is moving away from the storage location toward the entryway.
- 25. The acceptor of claim 24 further including an interrupt line coupled to the controller, wherein when the sensor is operated in the third mode, signals on the interrupt line that are based on signals from the optical receiver are indicative of whether the document is moving along the transport path away from the storage location toward the entryway.
- 26. The acceptor of claim 25 further including circuitry coupled between the optical receiver and the interrupt line for converting amplitude changes in electrical signals from the optical receiver to one or more pulses when the sensor is operated in the third mode.
- 27. The acceptor of claim 26 wherein the circuitry includes a clocked differentiator.
- 28. The acceptor of claim 25 further including a comparator coupled between the interrupt line and the optical receiver for comparing a signal based on an output of the optical receiver to a fixed amplitude.
- 29. A document acceptor comprising:
- a document transport path;
- an optical sensor disposed adjacent the document transport path, wherein the optical sensor includes a light emitting device and an optical receiver;
- a controller for operating the sensor in at least either a first mode or a second mode and for processing signals based on an output from the sensor;
- wherein when the sensor is operated in the first mode electrical signals originating from the optical receiver are used to determine an absence or presence of the document at a position along the path, wherein when the sensor is operated in the second mode electrical signals originating from the optical receiver are indicative of whether the document includes a predetermined pattern, and wherein signals from the controller determine an amplitude of light to be emitted by the light emitting device, wherein the amplitude of light depends on whether the sensor is to be operated in the first mode or second mode.
- 30. The acceptor of claim 29 further including:
- a sample and hold circuit having an output coupled to the light emitting device; and
- a digital-to-analog converter having inputs coupled to the controller, and having an output which can be coupled selectively to the sample and hold circuit, wherein signals provided to the digital-to-analog converter by the controller control the amplitude of light to be emitted by the light emitting device.
- 31. The acceptor of claim 29 wherein when the sensor is operated in the first mode, an amplitude of light emitted by the light emitting device saturates the optical receiver in the absence of a document intersecting an optical path from the light emitting device to the optical receiver.
- 32. The acceptor of claim 31 wherein when the sensor is operated in the first mode and a document intersects the optical path from the light emitting device to the optical receiver, the sensor is no longer saturated.
- 33. The acceptor of claim 29 wherein when the sensor is operated in the first mode, the controller uses electrical signals originating at the optical receiver to sense an edge of the document.
- 34. A document acceptor comprising:
- a document transport path;
- an optical sensor disposed adjacent the document transport path, wherein the optical sensor includes a light emitting device and an optical receiver;
- a controller for operating the sensor in at least either a first mode or a second mode and for processing signals based on an output from the sensor;
- first processing circuitry coupling an output of the sensor to the controller and which processes electrical signals originating at the optical receiver when the sensor is operated in the first mode; and second processing circuitry coupling an output of the sensor to the controller and which processes electrical signals originating at the optical receiver when the sensor is operated in the second mode, wherein the second processing circuitry includes pattern discrimination circuitry that includes a clocked differentiator and converts amplitude changes in an electrical signal originating at the optical receiver to one or more pulses;
- wherein when the sensor is operated in the first mode electrical signals originating from the optical receiver are used to determine an absence or presence of the document at a position along the path, and wherein when the sensor is operated in the second mode electrical signals originating from the optical receiver are indicative of whether the document includes a predetermined pattern.
- 35. A document acceptor comprising:
- an entryway through which a document is inserted;
- a document storage location;
- a document transport path for transporting a document inserted through the entryway toward the storage location;
- an optical sensor disposed adjacent the document transport path, wherein the optical sensor includes a light emitting device and an optical receiver;
- a controller for operating the sensor in at least either a first mode, a second mode or a third mode and for processing signals based on an output from the sensor;
- an interrupt line coupled between the optical sensor and the controller;
- wherein when the sensor is operated in the first mode electrical signals originating from the optical receiver are used to determine an absence or presence of the document at a position along the path, wherein when the sensor is operated in the second mode electrical signals originating from the optical receiver are indicative of whether the document includes a predetermined pattern, and
- wherein, when the sensor is operated in the third mode, signals on the interrupt line that are based on signals from the optical receiver are indicative of whether the document is moving along the transport path away from the storage location toward the entryway.
- 36. A method of accepting a document, the method comprising:
- causing the document to move along a transport path;
- sensing a leading edge of the document as it moves along the path using an optical sensor operating in a first mode;
- controlling the optical sensor to operate in a second mode after the leading edge of the document is sensed, wherein during the second mode, the sensor primarily uses light in a frequency range substantially different from a frequency range of light used during the first mode; and
- obtaining data indicative of whether the document includes a predetermined pattern based on signals sensed by the optical sensor while operating in the second mode.
- 37. The method of claim 36 wherein sensing further includes transmitting light from a first light emitting device across the document transport path and reflecting the transmitted light back across the document transport path.
- 38. The method of claim 36 wherein sensing includes operating a first light emitting device at an amplitude that saturates an optical receiver when the document does not intersect a path of the light from the first light emitting device.
- 39. The method of claim 38 wherein sensing further includes operating the first light emitting device at an amplitude that does not saturate the optical receiver when the document intersects the path of light from the first light emitting device.
- 40. The method of claim 39 wherein obtaining data further includes reflecting the optical signal of a second light emitting device off the document.
- 41. The method of claim 36, wherein sensing the leading edge includes providing an optical signal from a first light emitting device operating at a first wavelength and wherein obtaining data includes providing an optical signal from a second light emitting device operating at a second wavelength, wherein the method further includes:
- sampling analog output signals from the optical receiver; and
- using the sampled signals to adjust a brightness of the second light emitting device when the sensor is operated in the second mode.
- 42. The method of claim of claim 36 wherein sensing the leading edge includes:
- providing a first optical signal from a first light emitting device; and
- transmitting the first optical signal across the document transport path and reflecting the transmitted optical signal back across the document transport path.
- 43. The method of claim 42 wherein obtaining data includes:
- providing a second optical signal from a second light emitting device; and
- reflecting the second optical signal off the document.
- 44. The method of claim 36 further including:
- controlling the optical sensor to operate in the first mode after performing the step of obtaining data;
- sensing a trailing edge of the document using the optical sensor operating in the first mode; and
- holding the document in a selected position in the document transport path after sensing the trailing edge; and
- analyzing data obtained while the document travelled along the document transport path to determine whether the document is a genuine document.
- 45. The method of claim 44 wherein analyzing data includes analyzing the data obtained by the optical sensor while operating in the second mode.
- 46. The method of claim 44 further including:
- controlling a motor to transport the document toward a storage location if the document is determined to be genuine; and
- controlling the optical sensor to operate in an anti-cheat mode while the document is transported toward the storage location.
- 47. The method of claim 46 further including:
- obtaining electrical signals originating at the sensor while operated in the third mode; and
- using the signals obtained while the sensor is operated in the third mode to determine whether the document is moving away from the storage location.
- 48. The method of claim 47 further including:
- reversing the motor if it is determined that the document is moving away from the storage location; and
- ejecting the document.
- 49. A method of accepting a document, the method comprising:
- causing the document to move along a transport path;
- sensing a leading edge of the document as it moves along the path using an optical sensor operating in a first mode;
- controlling the optical sensor to operate in a second mode after the leading edge of the document is sensed, wherein a brightness of light associated with the sensor is adjusted depending on the mode in which the sensor is operated; and
- obtaining data indicative of whether the document includes a predetermined pattern based on signals sensed by the optical sensor while operating in the second mode.
RELATED APPLICATIONS
This invention is related to U.S. patent application Ser. No. 08/941,400, now U.S. Pat. No. 5,855,268 entitled "Optical Sensor System For A Bill Validator" and assigned to the assignee of the present invention. That application is incorporated herein by reference in its entirety.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0 720 128 A2 |
Jul 1996 |
EPX |