Principle and application of laser displacement monitor

　　 Laser Displacement Monitor It is a sensor that uses laser technology for measurement, consisting of a laser, a laser detector, and a measurement circuit. As a new measuring device, the laser displacement monitor can accurately and non-contactly measure the position, displacement, and other changes of the measured object, and can measure precise geometric measurements such as displacement, thickness, vibration, distance, and diameter.

　　Principle of Laser Displacement Monitor:

　　Currently, laser displacement monitors can be divided into two types according to their principles: laser triangulation and laser echo analysis. Laser triangulation is suitable for high-precision, short-distance measurements, while laser echo analysis is suitable for long-distance measurements. Currently, in industrial robot applications, triangulation is usually used. This method has a maximum linearity of 1um and a resolution of 0.1um.

　　The principle of triangulation is to project a red laser beam onto the surface of the object being measured through a lens. The laser reflected by the object passes through the receiver lens and is received by the internal CCD linear camera. Depending on the distance, the CCD linear camera can "see" this light spot from different angles. Based on 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 tested.

　　Simultaneously, the laser displacement monitor processes the light beam through analog and digital circuits at the receiver, and the microprocessor analyzes and calculates the corresponding output value. It then outputs a standard data signal proportionally within the user-set analog window. If using switch output, it transmits within the set window and exits outside the window. In addition, the analog and switch outputs can independently set the detection window.

　　The echo analysis method involves the laser emitter emitting one million laser pulses per second to the detector, which then returns to the receiver. The processor calculates the distance value by calculating the time it takes for the laser pulse to hit the detected object and return to the receiver. This output value is the average output of thousands of measurement results, i.e., pulse time-of-flight measurement. Laser echo analysis is suitable for long-distance detection, but the measurement accuracy is lower than laser triangulation, with a maximum detection distance of 250 meters.

　　Laser displacement monitors are often used to measure physical quantities, including length, distance, vibration, speed, and direction. They can also be used for flaw detection and atmospheric pollutant monitoring.

　　 Laser Displacement Monitor Use Cases:

　　In order to maintain the flatness of the glass, the temperature must be accurately controlled over a larger range. Because when a temperature difference occurs within the glass substrate, residual stress is generated, causing glass deformation such as bending, glass deformation during cutting, affecting the stability of the glass substrate, and the result of residual stress will lead to the sticking of the polarizing plate in the process, and the stress will also cause scars on the glass surface, resulting in damage to the substrate.

　　Using Laser Displacement Monitor ，can successfully measure the flatness of transparent materials, making up for the shortcomings of traditional laser displacement monitors in measuring transparent materials or mirror reflections, and increasing new application areas for laser displacement sensors.