Development Of Laser Distance Sensors:

Development of laser distance sensors:

The application of laser in the field of detection is very extensive, and the technical content is very rich, and the impact on social production and life is also very obvious. Laser ranging is one of the applications of lasers. This is because the laser has many advantages such as strong directivity, high brightness, and good monochromaticity. Before 1965, the Soviet Union used laser to measure the distance between the Earth and the Moon (384401km) with an error of only 250m. In 1969, when the Americans landed on the moon, they placed mirrors on the lunar surface. They also used lasers to measure the distance between the earth and the moon. The error was only 15 cm. The basic principle of using laser transmission time to measure distance is to determine the target distance by measuring the time it takes for the laser to travel to and from the target. which is:. Although laser ranging is simple in principle and simple in structure, it was mainly used in military and scientific research, but it is rare in industrial automation. Because laser ranging sensors are too expensive, they are typically in the thousands of dollars. In fact, all industrial users are looking for a sensor that enables precise distance detection over long distances. Because in many cases the proximity of the sensor will be limited by the physical location and production environment, today's laser range sensors will solve the problem for engineers in such situations. *Laser distance sensor working principle: When working, the laser diode is first directed to the target to emit laser pulses. The laser scatters in all directions after being reflected by the target. Part of the scattered light is returned to the sensor receiver, which is received by the optical system and imaged onto the avalanche photodiode. An avalanche photodiode is an optical sensor with an internal amplification function, so it can detect very weak optical signals. The target distance can be determined by recording and processing the time elapsed from the time the light pulse is emitted until the return is received. Laser sensors need to accurately measure the transmission time because the speed of light is too fast. For example, the speed of light is about 3X10^8m/s. To achieve a resolution of 1mm, the electronic circuit of the distance measuring sensor needs to be able to distinguish the following extremely short time: 0.001m (3X10^8m/s) = 3ps. 3ps time, this is an excessive demand for electronic technology, and the implementation cost is too high. But today's inexpensive laser sensors cleverly avoid this obstacle, using a simple statistical principle, that is, the averaging rule achieves a resolution of 1mm and guarantees response speed. * Solve problems that cannot be solved by other technologies: Laser distance sensors can be used in applications where other technologies cannot be used. For example, when the target is very close, the calculation of a common photoelectric sensor from the target reflected light can also perform a large number of precise position detection tasks. However, when the target distance is far or the target color changes, the ordinary photoelectric sensor is difficult to cope with.