Laser displacement sensors can non-contact measure the position, displacement, and other changes of the measured object, mainly used for measuring geometric quantities such as displacement, thickness, vibration, distance, diameter, etc. of the detected object. According to the measurement principle, the laser displacement sensor principle is divided into laser triangulation method and laser echo analysis method. The laser triangulation method is generally applicable to high-precision and short distance measurement, while the laser echo analysis method is used for remote measurement. The following two measurement methods of the laser displacement sensor principle are introduced respectively.

　　Comparison between optical displacement sensors and other displacement sensors

　　Eddy current displacement sensor

　　Resolution: The resolution of the eddy current sensor can also reach 0.1um, which is basically equivalent to that of the laser displacement sensor

　　Linearity: The linearity of eddy current sensors is generally low, around 1% of the range, while that of excellent laser displacement sensors is generally 0.1%

　　Measurement conditions: The eddy current sensor requires that the measured object be a conductor and non magnetic, i.e. a non magnetic conductor, such as aluminum, copper, etc. Iron cannot do it. Laser displacement sensors can measure whether the measured object is magnetic or conductive.

　　Comparison between laser displacement sensors and other displacement sensors

　　Capacitive displacement sensor

　　The precision of capacitive displacement sensors is very high, much higher than that of laser displacement sensors. However, the range of capacitive displacement sensors is very small, usually less than 1mm, and the range of laser displacement sensors can reach 2m.