Patent ID: 9109888
Filing Date: 2015-08-18
Classification: G01C,G01S

Abstract:
1. A distance measuring system comprising: a light emitter that emits light toward a target object; a light receiver that receives reflected light of the emitted light from the target object and produces an output corresponding to an amount of light received; a controller for controlling the light emitter and the light receiver; and a distance calculating unit that calculates a distance to the target object by means of a time-of-flight method using the output of the light receiver, wherein the controller further comprises: a sequencer that regulates a light emission timing at which light is emitted from the light emitter and a light reception timing at which light is received by the light receiver; a reference clock signal generating unit that generates a reference clock signal and outputs the reference clock signal to the sequencer; a light emitter driver for driving the light emitter; a light receiver driver for driving the light receiver; and a timing correction unit interposed in a previous stage of the light emitter driver for correcting the light emission timing, wherein the timing correction unit includes a first delay time control circuit, a second delay time control circuit, a timing correction phase comparator, and a timing correction control logic circuit; the sequencer generates a reference signal synchronized with the reference clock signal, and inputs the reference signal to the first delay time control circuit and the second delay time control circuit; the second delay time control circuit receives the reference signal, which is input thereto, and outputs an offset signal in which timing of the reference signal is delayed; the timing correction phase comparator receives the offset signal and an output signal from the light emitter driver, which are input thereto, and outputs a phase comparison result; the timing correction control logic circuit reads the phase comparison result, and outputs a delay adjusting signal based on the phase comparison result; and the first delay time control circuit reads the delay adjusting signal, adjusts the timing of the reference signal, and outputs the same as a light emission timing adjustment signal to the light emitter driver.