Variable anti-counterfeiting computer hologram prepared based on femtosecond laser

Abstract

The invention relates to a variable anti-counterfeiting computer hologram prepared based on femtosecond laser, and belongs to the technical field of laser application. According to the invention, a hologram composed of micro-pit structures of three sizes is processed on a heat shrinkable film through femtosecond laser, information recorded by the hologram is formed by combining computer generatedholograms corresponding to two kinds of optical patterns, and the two kinds of optical patterns are shown under irradiation of the laser. By controlling the heating temperature, the heat shrinkable film shrinks, the micro-pit structure with the minimum size shrinks until the transmittance of incident light is hardly influenced, information recorded by the hologram is changed, and finally only oneoptical pattern is presented, so that the change of hologram imaging content is realized. The problems that single holographic imaging is poor in anti-counterfeiting capacity and a variable holographic imaging manufacturing process and an imaging device are complex and difficult to popularize at present are solved. The method is simple in imaging change principle, achieves integration of packagingand anti-counterfeiting, is high in operability, and can be applied to the field of product anti-counterfeiting and information encryption.

Description

technical field [0001] The invention relates to a variable anti-counterfeiting computer hologram prepared based on femtosecond laser, belonging to the technical field of laser applications. [0002] technical background [0003] With the development of social economy, anti-counterfeiting has become a field of great concern. It can not only protect the reputation of trademarks and brands, prevent enterprises from falling into unfair competition, but also protect consumer rights and public safety. As an anti-counterfeiting technical product, anti-counterfeiting marks have been widely used in production and life, including various embossed patterns, barcodes, two-dimensional codes, etc. At present, people have developed ink printing, mechanical embossing, electrochemical etching and other technologies for the manufacture of anti-counterfeiting marks. However, most of these processing technologies use anti-counterfeiting labels as anti-counterfeiting identification carriers, whi...

AI Technical Summary

Problems solved by technology

However, at present, the variable hologram mainly relies on metasurfaces, and its processing methods often use electron beam lithography and ion beam etching, which have problems such as complex process methods and long preparation cycles.

Moreover, the transformation of holographic imaging often requires the use of complex equipment such as polarizers and laser light sources of different wavelengths, which is not conducive to the practical application of variable holography in the field of anti-counterfeiting.

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