Principle and Application Scenarios of Laser Displacement Sensors

　　As the name suggests, laser displacement sensors utilize laser technology for measurement. Currently, there are two main principles for laser displacement sensors: the laser triangulation method and the laser echo analysis method. The laser triangulation method is primarily used for high-precision short-distance measurements, while the laser echo analysis method is employed for long-distance measurements. Nowadays, in industrial robotics, the triangulation method is predominantly used, offering a maximum linearity of up to 1 micron and a resolution as high as 0.1 micron.


　　The principle of the triangulation method involves directing visible red laser light through a lens onto the surface of the object being measured. The laser light reflected by the object is then captured by a receiving lens and detected by an internal CCD linear array camera. Depending on the distance, the CCD linear array camera operates from different angles to "see" this light spot. With this angle and the known distance between the laser and the camera, a digital signal processor can calculate the distance between the sensor and the object being measured.

　　Simultaneously, the beam undergoes analog and digital circuit processing at the receiver's position, and the microprocessor analyzes and measures the corresponding output values. Standard data signals are output proportionally within the user-set analog window. If using switch output, it will be activated within the set window and deactivated outside it. Additionally, the detection window for analog and switch outputs can be independently configured.

　　The principle of echo analysis involves the laser emitter sending a million laser pulses per second to the detection object and receiving them back at the receiver. The processor calculates the time required for the laser pulse to reach the detection object and return to the receiver, providing distance values. The output value is the average of thousands of measurement results, obtained using the so-called pulse time method. The laser echo analysis method is suitable for long-distance detection but offers lower measurement accuracy compared to the laser triangulation method, with a maximum detection range of up to 250 meters.

　　Laser displacement sensors can accurately measure changes in the position, length, distance, vibration, speed, and direction of the measured object. They find widespread applications in various scenarios, including dimension measurement, thickness measurement of metal sheets and plates, measurement of cylinder barrels, comparison of workpiece heights, identification of defective parts, position recognition of small components, monitoring of parts on conveyor belts, vibration analysis, collision test measurements, automotive-related tests, and more.