Explanation of the principle of laser rangefinder

Laser rangefinder

Laser rangefinder are well known to us because of the popularity of handheld rangefinders. Handheld laser rangefinders are easy to operate and affordable. They are used in industrial and non-industrial applications. In addition to handheld laser rangefinders, industrial There is also a laser ranging sensor with higher accuracy and smaller size, which is also widely used in large and small industries due to its convenient ranging feature.
The principle of triangulation
The laser beam emitted by the semiconductor laser irradiates the target. The receiver lens gathers the light reflected by the target and focuses it on the photosensitive element. When the distance to the target changes, the angle of the reflected light passing through the receiver lens will change accordingly, and the position where the light focuses on the photosensitive element will also be different.

Principles of time measurement
The distance is measured during the time the luminous laser hits the object and returns. It does not affect the surface condition of the workpiece, and can perform stable detection. Detect the time T of receiving the reflected laser light in the picture on the right, and calculate the distance Y.
Calculation formula: 2Y (round trip distance) = C (speed of light) × T (time to receive reflected light).

Principle of Confocal Measurement
There is a lens inside the measurement section. The lens has a fixed focal distance, and the focal distance of the lens is set to F. When the lens is used for condensing, when the height is F, the focus coincides and the light is condensed to one point. When the height deviates from F, the light gradually becomes blurred.
The height of the tuning fork (lens) when the amount of reflected light is the strongest is determined, and it is clear at a glance whether the target is located at the focal distance F away from that point. The position of the tuning fork (lens) at this time can be measured with high precision through the internal sensor, and the distance to the target can be measured. Since it measures the focus height, it can achieve accurate measurement without being affected by the target material, color, tilt, etc.