A variable anti-counterfeiting computer hologram based on femtosecond laser preparation

Abstract

The invention relates to a variable anti-counterfeiting computer hologram prepared based on femtosecond laser, which belongs to the technical field of laser application. The invention uses a femtosecond laser to process a hologram composed of micro-pit structures of three sizes on the heat shrinkable film. The information recorded in the hologram is composed of computer-generated holograms corresponding to two optical patterns, which are presented under the irradiation of laser light. Two optical patterns. By controlling the heating temperature, the heat-shrinkable film is shrunk, and the micro-pit structure of the smallest size is shrunk to have little effect on the transmittance of incident light, changing the information recorded by the hologram, and finally presenting only one optical pattern, thus realizing Changes in the imaging content of the hologram. To solve the problem that the current single holographic imaging has poor anti-counterfeiting ability, and the variable holographic imaging manufacturing process and imaging device are complicated and difficult to popularize. The method has a simple imaging change principle, realizes the integration of packaging and anti-counterfeiting, has strong operability, and can be applied to the fields of product anti-counterfeiting and information encryption.

Description

Technical field [0001] The present invention relates to a variable anti-counterfeiting computer hologram based on femtosecond laser, belonging to the field of laser applications. [0002] technical background [0003] With the development of social economy, anti-counterfeiting has become a field of concern. It not only protects the reputation of trademarks and brands, not only in the unfair competition, but also protects consumer rights and public safety. Anti-counterfeiting identifier is widely used in production and life, including various embossed patterns, barcodes, QR code, etc. Currently, there have been developed various techniques such as ink printing, mechanical imprint, and electrochemical etching. However, these processing technologies are mostly an anti-counterfeiting label as an anti-counterfeiting identity vector, and there is a problem that is easy to defeat, is easily damaged or reused for counterfeiting goods. The laser marking technique is directly processed dire...

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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