Laser displacement sensor can accurately and non-contact measurement of the position, displacement and other changes of the object to be measured, mainly used in the measurement of geometric quantities such as displacement, thickness, vibration, distance, diameter of the detected object.

According to the measurement principle, the principle of laser displacement sensor is divided into laser triangulation method and laser echo analysis method. The laser triangulation method is generally suitable for high-precision and short-distance measurement, while the laser echo analysis method is used for long-distance measurement. Two measurement methods of the principle of laser displacement sensor are introduced.

triangulation

The laser transmitter shoots the visible red laser to the surface of the object to be measured through the lens, and the laser light scattered by the surface of the object passes through the receiver lens and is received by the internal CCD linear camera. According to different distances, the CCD linear camera can see" this light. From this angle and the known distance between the laser and the camera, the digital signal processor can calculate the distance between the sensor and the object being measured.

At the same time, the beam is processed by analog and digital circuits at the position of the receiving element, and analyzed by the microprocessor to calculate the corresponding output value, and output the standard data signal proportionally within the analog window set by the user. If the switch output is used, it will be turned on within the set window and turned off outside the window. In addition, the detection window can be set independently for analog quantity and switch quantity output.

The maximum linearity of the laser displacement sensor using the triangulation method can reach 1um, and the resolution can reach the level of 0.1um. For example, the ZLDS100 type sensor can achieve 0.01% high resolution, 0.1% high linearity, 9.4KHz high response, and adapt to harsh environments.

echo analysis

Laser displacement sensors use the principle of echo analysis to measure distance to a certain degree of accuracy. The inside of the sensor is composed of a processor unit, an echo processing unit, a laser transmitter, and a laser receiver. The laser displacement sensor transmits one million laser pulses per second to the detection object through the laser transmitter and returns to the receiver. The processor calculates the time required for the laser pulse to meet the detection object and return to the receiver, thereby calculating the distance value , the output value is the average output of thousands of measurement results. It is measured by the so-called pulse time method. The laser echo analysis method is suitable for long-distance detection, but the measurement accuracy is lower than that of the laser triangulation method, and the longest detection distance can reach 250m.