Introduction to the working principle of laser rangefinder and definition of safe laser

Laser rangefinders usually use two methods to measure distance: pulse method and phase method. The process of pulse ranging is as follows: the laser emitted by the range finder is reflected by the measured object and received by the range finder, and the range finder records the laser round trip time at the same time. Half of the product of the speed of light and round-trip time is the distance between the rangefinder and the object being measured. The accuracy of pulse ranging is generally in /-About 1 meter. In addition, the blind area of this rangefinder is generally about 15 meters. What is the main application field of laser rangefinder? Laser rangefinders have been widely used in the following fields: electricity, water conservancy, communications, environment, construction, geology, police, fire fighting, blasting, navigation, railway, anti-terrorism/military, agriculture, forestry, real estate, leisure/outdoor sports, etc. Why is there a difference between 'safe' and 'unsafe' laser rangefinders? As the name implies, laser rangefinder uses laser as the main working substance for work. At present, the working materials of hand-held laser rangefinder in the market mainly include: Semiconductor lasers with working wavelengths of 905 nm and 1540 nm, and YAG lasers with working wavelengths of 1064 nm. 1064 nm wavelength is harmful to human skin and eyes, especially if the eyes accidentally come into contact with 1064 nm wavelength laser, the damage to the eyes may be permanent. Therefore, foreign laser rangefinders have completely banned 1064 nm laser. In China, some manufacturers also produce 1064 nm laser rangefinders. For 905 nm and 1540 nm laser rangefinders, we call them 'safe '. For 1064 nm laser rangefinder, we call it 'unsafe' because it has potential harm to human body.