The role of laser field lens and beam expander

The laser beam in the marking system will produce off-axis deflection after passing through the focusing lens system. Relative to an ideal plane, abnormal images or distortion will appear on the marking surface. （CO2 F Theta lens factory China）The flat-field focusing lens, also called field lens, f-theta focusing lens, is a professional lens system whose purpose is to form a uniform focused spot of the laser beam in the entire marking plane, which is the most important part of a laser marking machine One of the accessories.

Field lens can be divided into f-theta lens and telecentric lens. Due to the high cost and expense of telecentric lenses, F-theta lenses are mainly used in laser marking machines for industrial applications. Without distortion, the position of the focus point depends on the focal length of the lens and the tangent of the deflection angle, and the position of the focus point only depends on the focal length and the deflection angle, which simplifies the calculation method of focus positioning.

Variable Zoom Laser Beam Expanders，As an indispensable optical component in the laser marking machine system, the laser beam expander can change the laser beam diameter and divergence angle of the lens assembly. The laser beam emitted from the laser has a certain divergence angle. For laser processing, only by adjusting the beam expander to make the laser beam a collimated (parallel) beam can the focusing lens be used to obtain a small high-power density spot; In the distance measurement, the beam expander must be used to maximize the collimation of the laser to obtain the ideal long-distance measurement effect; the beam diameter can be changed by the beam expander to be used for different optical instruments; the beam expander cooperates with the spatial filter The use of light sheets can make the asymmetric beam distribution become symmetrical and make the light energy distribution more uniform.