What is the effect of 355nm uv solid state lasers marking on glass?

UV laser marking on flat glass is directly related to the peak power of the laser, the size of the focused spot, and the speed of the galvanometer.

We have found that sometimes the light from high power lasers does not etch the glass surface, but passes directly through. This is because the peak power of the laser is not enough, or the energy density is not concentrated enough. The peak power is affected by the laser crystal, pulse width and frequency. The narrower the pulse width and the lower the frequency, the higher the peak power of the laser.

Although some can be etched on the surface of the glass, it still produces the phenomenon of leaking points, and some points formed by the pulse will sink into the glass to form internal carvings. In this case, high peak power lasers and high magnification beam expansion can be used to optimize. processing effect.

In addition, the time that the laser beam contacts the glass surface also affects the etching effect of the glass surface. Too long contact time may cause the glass surface to be hit too deep, and too short a contact time may cause leakage. We can get better processing results by changing the scanning speed of the galvanometer to an appropriate value. However, it should be noted that the scanning speed is also affected by the frequency of the laser itself, and if the frequency is too low, it will also lead to leakage.

Curved glass

Due to the influence of the bending force, the focal depth of the focusing spot and the scanning method of the galvanometer are particularly important to the processing effect, that is, the peak power of the laser, the focusing spot, the scanning speed of the galvanometer, the scanning method of the galvanometer, the focal depth of the spot and the range of the field lens. etc. affected. When the energy density reaches the standard, we will find that the effect on the glass surface is worse as it goes to the edge, and it cannot even be processed on the surface. The reason is that the depth of focus is too shallow. The focal depth is affected by the M2 factor of the laser beam, the spot size of the beam expander, and the range of the field lens. The magnification of the beam expander and the range of the field lens both affect the focal length. The shorter the focal length, the more concentrated the energy density and the shallower the depth of focus.

Under the 10x beam expansion, the energy density is relatively concentrated and the surface is delicate, but due to the shallow depth of focus, the lasers on both sides do not work on the surface. Under the 8x beam expansion, for the current curved product, the focal depth and energy are more suitable, and the marking effect is better. However, the 6-fold beam expansion focal depth increases and also reduces the energy density, so there are many leaks and the effect is poor.

In conclusion, for such glass materials with large curved surfaces and high hardness, lasers with better beam quality and narrower pulse width should be selected. It is more appropriate to use appropriate beam expanders or 3D zoom galvanometers to process such products. .