Measurement Methods and Applications of Laser Rangefinders
Laser rangefinders generally adopt two methods for distance measurement: the pulse method and the phase-shift method.
Pulse ranging: The laser emitted by the rangefinder is reflected by the measured object and then received by the rangefinder. The instrument records the round-trip time of the laser at the same time. Half the product of the speed of light and the round-trip time equals the distance between the rangefinder and the target object. The measurement accuracy of the pulse method is generally around ±1 meter. The blind zone of this type of rangefinder is approximately 15 meters.
Application fields of laser rangefinders: Laser rangefinders are widely used in the following fields: electric power, water conservancy, communications, environmental monitoring, construction, geology, police work, fire protection, blasting, navigation, railways, counter-terrorism/military, agriculture, forestry, real estate, leisure and outdoor sports, etc.
Why are laser rangefinders classified as "safe" and "unsafe"?
Laser rangefinders operate using laser as the primary working medium. Currently, handheld laser rangefinders on the market mainly use the following laser sources: semiconductor lasers with operating wavelengths of 905 nm and 1540 nm, and YAG lasers with an operating wavelength of 1064 nm. The 1064 nm wavelength is harmful to human skin and eyes. Particularly if the human eye is accidentally exposed to 1064 nm laser radiation, eye damage may be permanent. Therefore, 1064 nm lasers have been completely banned in handheld laser rangefinders overseas. In China, some manufacturers still produce 1064 nm laser rangefinders.
Laser rangefinders using 905 nm and 1540 nm lasers are referred to as "safe". Those with 1064 nm lasers are classified as "unsafe" due to their potential hazards to the human body.
