Analysis And Experimental Research Of Color Marking Based On LIPSS Structure Mechanism

With the development of industry,laser processing is playing an increasingly important role in the micro-nano field.Among them,laser-induced surface periodic structure(LIPSS)is an important method in micro-nano processing.LIPSS is a micron or even nanometer grating structure formed by laser on the surface of material.This structure has been extremely widely used in many fields,for example,structure color,changing the surface friction performance and wettability of the object,anticounterfeiting and many other applications.Even in the fields of chemical and biology fields there will still have good development prospects for it.The laser marking method based on the LIPSS structure is a physical coloring method,also known as a structural coloring method.Compared to traditional laser marking,it has many advantages such as not easy to oxidize,high temperature resistance,chemical corrosion resistance and biological corrosion resistance,and its color will change with the observation angle.This article introduces and analyzes the color forming mechanism of LIPSS structure.It is believed that the metal forming mechanism of LIPSS structure is the "grating diffraction" of the micro-stripe structure.Numerical simulations were carried out on the color characteristics of the LIPSS structure on the metal surface,focusing on the visible spectrum(380-780nm),the reflection spectrum of light waves obtained under different incident angles and reflection angles,and its colorimetry was analyzed.Furthermore,the influence of the thickness of the oxide film layer,the period of the LIPSS structure,the ablation depth,etc.on the LIPSS size structure(period size,depth size)of different physical sizes is analyzed.Based on the above-mentioned LIPSS structure theory,a picosecond pulsed laser processing optical experiment was built.A periodic surface structure was built on the metal surface.Pulse dotting and laser scanning experiments with different parameters were analyzed,and the surface morphology was observed under different microscopes,which confirmed that microstructure of the LIPSS structure is stripe structure.Comparing the color of samples under different processing parameters,we got the best laser processing parameters,and verify each other with numerical simulation and we get the same result.Finally,the laser multi-writing experiment was carried out,and comparing with laser direct writing,laser multi-writing samples has better color quality than laser direct writing.It makes up for the problem that the color of the laser direct writing LIPSS structure depends on the horizontal observation angle,and compares the laser rewriting LIPSS structure and the laser direct writing LIPSS structure to get the difference and connection between the Laser direct-writing and Laser multi-writing.