The relationship between field lens, beam expander and galvanometer
There are important optical devices such as field lens, beam expander and galvanometer in the optical path system of laser marking machine. What kind of relationship exists between them and the problems that need attention in matching?
Field lens: Laser equipment mainly has a component called-field lens. It is to determine the laser working range of the laser marking machine.
It is mainly used to focus the light from the galvanometer on a plane. To put it simply, it is a focusing lens. The field lens has a parameter called the entrance pupil, also called the entrance pupil. We require that the entrance pupil of the field lens ≥ the spot of the galvanometer. If the entrance pupil of the field lens is smaller than the spot of the galvanometer, it may appear. When marking to the edge of the field lens, the edge will be marked significantly lighter than the middle position, or even appear The range that can be hit will be smaller than the nominal range of the field lens.
Beam expander: actually two lenses with different focal lengths. When the laser equipment is used for long-distance illumination or projection, as well as related aspects of the focusing system. An important part of laser marking machine laser is called laser beam expander, which plays a very important role. The beam expander is an optical device that expands the laser beam.
Fixed Magnification Beam Expanders
The functions of the beam expander are as follows:
First: make the focusing effect better and get a smaller focusing spot. The larger the multiple of the beam expander, the better the effect of focusing by the focusing lens.
Second: Disperse the energy evenly, reduce the energy density reaching the vibrating lens or the reflector, and make the vibrating lens or the 45-degree reflector more durable.
Third: Amplify the beam. This is mainly reflected in the laser show system. Although we amplify the beam every time in the industrial processing system, our purpose is not only to enlarge the beam but the first two purposes. In the laser show system The purpose of using a beam expander is to enlarge the beam.
Galvanometer: It is two ammeters + pointers tied to X\Y lenses, and the number of galvanometer spots (10 spots, 12 spots, 20 spots, etc.) is what the area of the galvanometer lens can reflect. The smaller the galvanometer lens, the smaller the beam that can be reflected; the larger the galvanometer lens, the larger the beam that can be reflected. But we should pay attention that the larger the galvanometer lens, the heavier the weight of the galvanometer lens. When something with heavier weight moves, the greater the inertia. The greater the inertia will inevitably cause the speed of our galvanometer to be slower. . Why choose Dazhen lens? In order to obtain a beam with a smaller divergence angle, a large multiple beam expander is used, and a large multiple beam expander is used, then a large beam will inevitably come out, and the large beam must be reflected by the corresponding galvanometer. However, the line fineness and marking speed is a contradiction, we can only choose according to needs, not the best of both.