LASER DISTANCE MEASURING METHOD

摘要

PURPOSE:To measure exactly and easily the distance up to an object to be measured without using an optical system for superposing laser light by dividing laser light to two optical paths, using the beat signal of the laser light passing one optical path as a reference signal and irradiating the laser light passing the other optical path to the object to be measured. CONSTITUTION:The two beams of the laser light having the frequencies different slightly from each other are projected from one laser 1 and are separated to two respective optical paths by a partial reflecting mirror 2. The beat signal of the laser light progressed in one optical path is used as the reference signal and the laser light progressed through the other optical path is irradiated to the object 5' to be measured. The beat signal of the laser light reflected by the object 5' is thereupon used as the measurement signal and the phase difference between the measurement signal and the reference signal is detected by a phase detector 10 to determine the distance up to the object 5'. The need for the optical system for superposing two beams of the laser light is thus eliminated and since the two beams of the laser light are simultaneously oscillated, there is no deviation and the need for a fine adjustment is eliminated.