Traffic information system using light emitting diodes
First Claim
1. A traffic information system (10) for providing a visual signal in the form of light rays and for using the light rays to transmit information to a remotely located target (14), said system (10) comprising:
- traffic light means (18) comprising a plurality of light emitting diodes (24) for projecting light rays optically perceptible to humans;
power means for supplying power to illuminate said diodes (24) at a predetermined frequency having a duty cycle consisting of an ON period followed by an OFF period short enough to be humanly imperceivable whereby the light appears to be constantly illuminated to the human eye; and
modulator means for varying said predetermined frequency of said ON and OFF periods to transmit information with light which appears to be uninterrupted to the human eye.
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Accused Products
Abstract
A traffic information system (10) including a road (12), a vehicle (14) traveling on the road (12) and a traffic light assembly (16) operatively associated with the road (12) is disclosed. The system (10) includes a traffic light assembly (16) comprising at least one traffic light or lamp means (18). The traffic light (18) includes a plurality of light emitting diodes (24) for projecting light rays to the vehicle (14) to provide the driver of the vehicle (14) with a visual signal. The system (10) further comprises a transmitter (20) including a power supply (30) and a modulator (72) for turning the diodes (24) on and off at a rate that is imperceivable to humans while optically transmitting information to a receiver (22) disposed on the vehicle (14).
362 Citations
73 Claims
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1. A traffic information system (10) for providing a visual signal in the form of light rays and for using the light rays to transmit information to a remotely located target (14), said system (10) comprising:
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traffic light means (18) comprising a plurality of light emitting diodes (24) for projecting light rays optically perceptible to humans; power means for supplying power to illuminate said diodes (24) at a predetermined frequency having a duty cycle consisting of an ON period followed by an OFF period short enough to be humanly imperceivable whereby the light appears to be constantly illuminated to the human eye; and modulator means for varying said predetermined frequency of said ON and OFF periods to transmit information with light which appears to be uninterrupted to the human eye. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A traffic information system (10) for transmitting information to a remotely located target (14), said system (10) comprising:
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traffic light means (16) for projecting light rays to a target (14), said traffic light means (16) including first light means (17) for projecting first light rays to the target (14) and second light means (19) for projecting second light rays to the target (14); a transmitter (20) including means for illuminating said first light means (17) at a first frequency to transmit said first light rays from said first light means (17) at said first frequency and for illuminating said second light means (19) at a second frequency to transmit said second light rays from said second light means (19) at said second frequency; a receiver (22,22'"'"') including photodetector means (88,88'"'"') for converting said first light rays into a first output signal of electric current having a first output frequency and for converting said second light rays into a second output signal of electric current having a second output frequency; and
characterized bysaid receiver (22,22'"'"') further including differential means (92,92'"'"') for differentiating said first output frequency from said second output frequency to detect the presence of one of said first or second light rays. - View Dependent Claims (32, 33, 34, 35)
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36. A traffic light assembly (16) for transmitting information to a remotely located target (14), said assembly (16) comprising:
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traffic light means (18) comprising a plurality of light emitting diodes (24) for transmitting light rays from said traffic light assembly (16); d.c. power connection means (26) secured to said traffic light means (18) and electrically coupled to said diodes (24) for receiving d.c. power; a.c. power connection means (28) secured to said traffic light means (18) for receiving a.c. power; d.c. power supply means (30) secured to said traffic light means (18) and electrically coupled to and between said a.c. power connection means (28) and said d.c. power connection means (26) for converting a.c. power received by said a.c. power connection means (28) to d.c. power so that d.c. power is supplied to said d.c. power connection means (26); and
characterized bya battery (32) removably connected to said traffic light means (18) for supplying d.c. power to said d.c. power connection means (26) to illuminate said diodes (24). - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57)
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58. A method for transmitting information from a traffic light assembly (16) of the type having a plurality of light emitting diodes (24) to a location remote from the traffic light assembly (16), said method comprising the steps of:
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illuminating the diodes (24) to produce light optically perceivable to humans; turning the diodes (24) ON and OFF at a predetermined frequency having a duty cycle consisting of an ON period followed by an OFF period short enough to be humanly imperceivable whereby the light appears constantly illuminated to the human eye; and varying the frequency of the ON and OFF periods to transmit the information with light which appears to be uninterrupted to the human eye. - View Dependent Claims (59, 60, 61, 62, 63)
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64. A method for optically transmitting data from a traffic light assembly (16) to a receiver (22,22'"'"') disposed on a target (14) wherein the traffic light (18) is of the type for controlling the movement of the target (14) and is of the type including a first light (17) for projecting first light rays to the target (14) and a second light (19) for projecting second light rays to the target (14);
- said method comprising the steps of;
illuminating the first light (17) at a first frequency to transmit the first light rays from the first light (17) at the first frequency; illuminating the second light (19) at a second frequency to transmit the second light rays from the second light (19) at the second frequency; converting the first light rays into a first output signal of electric current having a first output frequency; converting the second light rays into a second output signal of electric current having a second output frequency; and differentiating the first output frequency from the second output frequency to detect the presence of either the first or second light rays.
- said method comprising the steps of;
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65. A traffic system (10) for optically transmitting information from a traffic light (18) to a vehicle (14), said system (10) comprising:
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a road (12); a vehicle (14) traveling on said road (12); a traffic light (18) operatively associated with said road (12), said traffic light (18) comprising at least one lamp means (24) for providing an illuminated signal optically perceivable to the human eye; transmitter means (20) for transmitting information from said traffic light (18) by turning said lamp means (24) ON and OFF at a predetermined frequency having a duty cycle consisting of an ON period followed by an OFF period short enough to be humanly imperceivable whereby the light appears constantly illuminated to the human eye; and receiver means (22,22'"'"') disposed on said vehicle (14) for optically receiving and decoding the information transmitted by said ON and OFF periods by an illuminated signal which appears to be uninterrupted to the human eye. - View Dependent Claims (66, 67, 68, 69, 70, 71)
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72. A traffic light assembly (16) for transmitting information and comprising:
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traffic light means (18) including a plurality of light emitting diodes (24) for transmitting light rays in the range clearly perceptible optically to the human eye at roadway distances in broad daylight; and power means for supplying power to illuminate said diodes (24) at a predetermined frequency having a duty cycle consisting of an ON period followed by an OFF period short enough to be optically imperceivable to the human eye so that the light appears to be constantly illuminated to the human eye while in operation whereby the illumination of said diodes is viewed at a traffic distance by the human eye as a traffic signal and a receiver decodes the ON and OFF periods which are imperceivable to the human and produces an independent information signal.
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73. A method for transmitting information from a traffic assembly comprising the steps of:
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illuminating a plurality of diodes to produce light rays in the range clearly perceptible optically to the human eye at roadway distances in broad daylight; turning the diodes ON and OFF at a predetermined frequency having a duty cycle consisting of an ON period followed by an OFF period short enough to be optically imperceivable to the human eye so that the light appears to be constantly illuminated to the human eye while in operation; viewing the light at a traffic distance in the range optically perceivable by the human eye as a traffic signal; decoding the humanly imperceivable ON and OFF periods with a photo detector; and producing an independent information signal in response to the decoding.
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Specification