Optical distance measurement apparatus and method using cleaning device
First Claim
1. An optical distance measurement apparatus comprising:
- light emitting means for emitting a high-power pulse light beam as a distance measuring medium to an object;
light receiving means for receiving a light beam reflected from the object;
trigger signal generation means, coupled to said light emitting means, for generating a trigger signal indicative of a start time point for measurement of a light moving time;
pollution sensing means for receiving a part of the light beam which is emitted from said light emitting means and then reflected from a protecting glass mounted on a front side of the apparatus, to sense a variation in a reflectivity of said protecting glass, and discriminating pollution on a front surface of said protecting glass in accordance with the sensed result;
diode abnormal state sensing means for receiving the part of the light beam which is emitted from said light emitting means and then reflected from said protecting glass, to sense an abnormal state of a light emitting laser diode in said light emitting means, and emitting a light beam to said light receiving means through said protecting glass to sense whether a light receiving photo diode in said light receiving means is in a normal or abnormal state and to output an output signal indicating whether or not the reflected light signal has been detected;
control/time-distance conversion means, coupled to said light emitting means, said light receiving means, said trigger generation means, said pollution sensing means, and said diode abnormal state sensing means, for controlling the entire operation of the apparatus in response to an output signal from said pollution sensing means and said output signal from said diode abnormal state sensing means, measuring the light moving time in response to the trigger signal from said trigger signal generation means and an output signal from said light receiving means and converting the measured light moving time into a distance to the object;
cleaning means for removing the pollution on the front surface of said protecting glass under the control of said control/time-distance conversion means; and
car collision prevention means for giving an alarm to the user and accelerating or decelerating a car under the control of said control/time-distance conversion means when a dangerous situation occurs in traveling of the car.
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Accused Products
Abstract
Optical distance measurement apparatus and method. The apparatus comprises a light emitting circuit, a light receiving circuit, a trigger signal generation circuit, a pollution sensor, a diode abnormal state sensor, a control/time-distance conversion circuit, a cleaning device and a car collision prevention device. The pollution sensor receives a part of a light beam which is emitted from the light emitting circuit and then reflected from protecting glass mounted on a front side of the apparatus, to sense a variation in a reflectivity of the protecting glass, and discriminates a polluted state of the protecting glass in accordance with the sensed result. The diode abnormal state sensor receives the part of the light beam which is emitted from the light emitting circuit and then reflected from the protecting glass, to sense an abnormal state of a light emitting laser diode in the light emitting circuit, and emits a light beam to the light receiving circuit through the protecting glass to sense an abnormal state of a light receiving photo diode in the light receiving circuit. The cleaning device removes pollution on a front surface of the protecting glass under control of the control/time-distance conversion circuit.
14 Citations
12 Claims
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1. An optical distance measurement apparatus comprising:
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light emitting means for emitting a high-power pulse light beam as a distance measuring medium to an object; light receiving means for receiving a light beam reflected from the object; trigger signal generation means, coupled to said light emitting means, for generating a trigger signal indicative of a start time point for measurement of a light moving time; pollution sensing means for receiving a part of the light beam which is emitted from said light emitting means and then reflected from a protecting glass mounted on a front side of the apparatus, to sense a variation in a reflectivity of said protecting glass, and discriminating pollution on a front surface of said protecting glass in accordance with the sensed result; diode abnormal state sensing means for receiving the part of the light beam which is emitted from said light emitting means and then reflected from said protecting glass, to sense an abnormal state of a light emitting laser diode in said light emitting means, and emitting a light beam to said light receiving means through said protecting glass to sense whether a light receiving photo diode in said light receiving means is in a normal or abnormal state and to output an output signal indicating whether or not the reflected light signal has been detected; control/time-distance conversion means, coupled to said light emitting means, said light receiving means, said trigger generation means, said pollution sensing means, and said diode abnormal state sensing means, for controlling the entire operation of the apparatus in response to an output signal from said pollution sensing means and said output signal from said diode abnormal state sensing means, measuring the light moving time in response to the trigger signal from said trigger signal generation means and an output signal from said light receiving means and converting the measured light moving time into a distance to the object; cleaning means for removing the pollution on the front surface of said protecting glass under the control of said control/time-distance conversion means; and car collision prevention means for giving an alarm to the user and accelerating or decelerating a car under the control of said control/time-distance conversion means when a dangerous situation occurs in traveling of the car. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An optical distance measurement method comprising the steps of:
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(a) driving a laser diode to emit a light beam to an object, receiving a part of the light beam which is emitted from said laser diode and then reflected from a protecting glass and sensing pollution on a front surface of said protecting glass in accordance with the received state; (b) sensing an error of said laser diode; (c) sensing an error of a photo diode for receiving the light beam from said laser diode; and (d) measuring a time delay value resulting from a temperature variation and obtaining an actual distance to the object on the basis of the measured time delay value, wherein said step (b) of sensing the error of said laser diode includes the steps of; (b-1) initializing a cleaning motor driver; (b-2) discriminating whether a first microswitch is at its ON state, determining that an error is present in said cleaning motor driver, if it is discriminated that said first microswitch is not at its ON state, and then driving an error alarm unit to give an alarm; (b-3) discriminating whether a laser diode state checking function is required, if it is discriminated at said step (b-2) that said first microswitch is at its ON state, returning the operation to said step (b-1) if it is discriminated that the laser diode state checking function is not required and moving a cleaning pad to a second microswitch if it is discriminated that the laser diode state checking function is required; (b-4) discriminating whether said second microswitch is at its ON state when said cleaning pad reaches said second microswitch; (b-5) driving said laser diode to emit the light beam, if it is discriminated at said step (b-4) that said second microswitch is at its ON state; (b-6) initializing said cleaning motor driver again to move said cleaning pad to its initial position, if it is discriminated at said step (b-4) that said second microswitch is not at its ON state, discriminating whether said first microswitch is at its ON state, driving said cleaning pad to perform the laser diode state checking function, if it is discriminated that said first microswitch is at its ON state, and discriminating whether said second microswitch is at its ON state; (b-7) determining that the error is present in said cleaning motor driver, if it is discriminated at said step (b-6) that said second microswitch is not at its ON state, driving said error alarm unit to give the alarm and performing said step (b-5) of driving said laser diode to emit the light beam, if it is discriminated at said step (b-6) that said second microswitch is at its ON state; and (b-8) checking, after performing said step (b-5), whether said photo diode receives a part of the light beam which is emitted from said laser diode and then reflected from a reflection surface of said cleaning pad, determining that the error is present in said laser diode, if it is checked that said photo diode receives the reflected light beam, returning the operation to said step (b-1), determining that the error is present in said laser diode, if it is checked that said photo diode receives no light beam, and then driving said error alarm unit to give the alarm. - View Dependent Claims (9, 10, 11)
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12. An optical distance measurement method comprising the steps of:
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(a) driving a laser diode to emit a light beam to an object receiving a part of the light beam which is emitted from said laser diode and then reflected from a protecting glass and sensing pollution on a front surface of said protecting glass in accordance with the received state; (b) sensing an error of said laser diode; (c) sensing an error of a photo diode for receiving the light beam from said laser diode; and (d) measuring a time delay value resulting from a temperature variation and obtaining an actual distance to the object on the basis of the measured time delay value, wherein said step (b) of sensing the error of said laser diode includes the steps of; (b-1) outputting a laser diode ON signal and checking an output signal from a diode abnormal state sensor; (b-2) ANDing the laser diode ON signal and the output signal from said diode abnormal state sensor and checking whether the ANDed signal is high in level; (b-3) determining that said laser diode is normal, if it is checked at said step (b-2) that the ANDed signal is high in level, and performing the operation normally; and (b-4) determining that said laser diode is abnormal, if it is checked at said step (b-2) that the ANDed signal is low in level, stopping the operation and informing the user of such a situation.
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Specification