US 5,633,706 AGranted

Optical distance measurement apparatus and method

AssigneeHyundai Electronics Industries Co., Ltd.

InventorsJung S. Cho, Young B. Im

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Abstract

An optical distance measurement apparatus comprises a system controller for controlling the entire operation of a system, a light emitting circuit for emitting a high-power pulse light beam as a distance measuring medium to an object in response to a drive signal from the system controller, a light receiving circuit for receiving a light beam reflected from the object, a trigger signal generation circuit for generating a trigger signal indicative of a start time point for measurement of a light moving time, and a time-distance conversion circuit for measuring the light moving time in response to the trigger signal from the trigger signal generation circuit and in response to an output signal from the light receiving circuit, and for converting the measured light moving time into a distance to the object. The time-distance conversion circuit obtains a time difference between the trigger signal from the trigger signal generation circuit and the output signal from the light receiving circuit and converts the obtained time difference into the distance to the object.

Claims11

Dependent claims

An optical distance measurement apparatus, comprising:

system control means for controlling an entire operation of a system and for generating a drive signal;
light emitting means responsive to said drive signal for emitting a high-power pulse light beam for measurement of a distance to an object;
light receiving means for receiving a light beam reflected from the object and generating an output signal;
trigger signal generation means for generating a trigger signal indicative of a start time point for measurement of a light moving time;
and
time-distance conversion means for measuring the light moving time in response to the trigger signal from said trigger signal generation means and said output signal from said light receiving means, and for converting the measured light moving time into a distance to the object;
wherein said trigger signal generation means includes a variable signal delay circuit for delaying the drive signal from said system control means for a desired time and for outputting the delayed drive signal as the trigger signal to said time-distance conversion means, and a signal delay adjustment unit for varying a time constant of said variable signal delay circuit to adjust the delay time thereof;
wherein said light emitting means includes:
a laser diode as a light source for producing the high-power pulse light beam;
a laser diode driving circuit for driving said laser diode in response to the drive signal from said system control means;
and
a light emitting lens for focusing the fight beam from said laser diode to produce a focused light beam and for diffusing the focused light beam at a desired angle so as to direct a diffused light beam to the object.

9 more elements

An optical distance measurement apparatus, comprising:

system control means for controlling an entire operation of a system and for generating a drive signal;
light emitting means responsive to said drive signal for emitting a high-power pulse light beam for measurement of a distance to an object;
light receiving means for receiving a light beam reflected from the object and generating an output signal;
trigger signal generation means for generating a trigger signal indicative of a start time point for measurement of a light moving time;
and
time-distance conversion means for measuring the light moving time in response to the trigger signal from said trigger signal generation means and said output signal from said light receiving means, and for converting the measured light moving time into a distance to the object;
wherein said trigger signal generation means includes a variable signal delay circuit for delaying the drive signal from said system control means for a desired time and for outputting the delayed drive signal as the trigger signal to said time-distance conversion means, and a signal delay adjustment unit for varying a time constant of said variable signal delay circuit to adjust the delay time thereof;
wherein said light receiving means includes:
a light receiving lens for condensing the light beam reflected from the object;
an infrared-ray filter for filtering the light beam condensed by said light receiving lens by passing only a part thereof, corresponding to the diffused light beam emitted from said light emitting means, so as to remove an external light beam therefrom;
a photo diode for performing a photoelectric conversion operation for the light beam filtered by said infrared-ray filter to produce an electrical signal;
an amplifier for amplifying the electrical signal from said photo diode to produce an amplified output signal;
and
a wave-shaping circuit for converting the amplified output signal from said amplifier into a digital signal and for outputting the converted digital signal to said time-distance conversion means.

11 more elements

Dependencies are inferred from the claim text.