The relationship among field mirror, beam expander and galvanometer in Laser marking machine
There are some important optical devices in the optical system of Laser marking machine, such as field mirror, beam expander and galvanometer. What kind of relationship exists between them and what problems need to be paid attention to in the matching? Let's take you to know: field mirror: laser equipment mainly has a component called field mirror. Is to determine the scope of Laser marking machine laser work. It is mainly used to focus the light from the galvanometer on a plane. The simple point is a focusing lens, and the complex point is a lens in which every point in a specified plane is the focus point. The field mirror has a parameter, which is called the entrance pupil. For the entrance pupil, we require the entrance pupil of the field mirror to be equal to or greater than the spot of the galvanometer. If the entrance pupil of the field mirror is smaller than the spot of the galvanometer, it is possible to mark the edge of the field mirror. When marking the edge of the field mirror, the edge will be marked shallower than the middle position, and even the scope that can be hit will be smaller than the scope of the field mirror.
Beam expander: when it comes to beam expanders, they are actually two lenses with different focal lengths. When laser equipment is used for long-distance lighting or projection, and related aspects of focusing system. An important part of Laser marking machine is called laser beam expander, which plays a very important role. A beam expander is an optical device that expands the laser beam. The product of beam waist radius and divergence angle is a constant value. When a laser beam passes through an x-fold beam expander, its waist radius increases by x-fold, but its divergence angle decreases to 1 / X of the original. When the laser beam with smaller divergence passes through the same size focusing lens, the focus point will be smaller. The effects of the beam expander are as follows:
First, make the focusing effect better and get smaller focusing spot. The larger the magnification is, the better the focusing effect of the beam will be.
The second is to evenly disperse the energy, reduce the energy density reaching the galvanometer or reflector, and make the galvanometer or 45 degree reflector more durable.
Third: amplifying the beam, which is mainly reflected in the laser performance system. Although we amplify the beam every time in the industrial processing system, our purpose is not only to amplify the beam, but also for the first two purposes. The purpose of using the beam expander in the laser performance system is to enlarge the beam.
Galvanometer: galvanometer in the final analysis is two ammeters + pointer tied XY lens, and we say the number of galvanometer facula (10 facula, 12 facula, 20 facula, etc.) is that the area of the galvanometer can reflect how much light beam. The smaller the galvanometer lens is, the smaller the reflected beam is; The larger the galvanometer lens is, the larger the beam can be reflected. However, we should pay attention to the fact that the bigger the galvanometer lens is, the heavier the galvanometer lens is. When the heavier things move, the greater the inertia is. The greater the inertia is, the faster the galvanometer will not be. Why choose galvanostatic lenses? Because in order to get the beam with smaller divergence angle, we will use the large expansion mirror. If we use the large expansion mirror, we will inevitably get a large beam, and the large beam must be reflected by the corresponding galvanometer. But the line fineness and marking speed are a contradiction, we can only choose according to the needs, not the best of both.