Optically variable anti-counterfeiting element

A technology for optically changing anti-counterfeiting and components, which is applied to patterns, identification devices, instruments, etc. characterized by light projection effects, and can solve problems such as affecting the anti-counterfeiting effect of anti-counterfeiting components and public confusion.

Active Publication Date: 2010-12-08
CHINA BANKNOTE SECURITY PRINTING TECH RES INST CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in this application, when the lighting conditions are poor, it is difficult for the naked eye to accurately identify this color change effect, which affects the anti-counterfeiting effect of the anti-counterfeiting element containing this liquid crystal material to a large extent.
[0009] To sum up, anti-counterfeiting using the angle-dependent color-changing effect of optical components or optically variable pigments has been widely used, and has played a very good role in anti-counterfeiting for a long period of time, but currently Optically variable pigments (OVP) and liquid crystal pigments for making such optically variable anti-counterfeiting elements can be easily obtained in the market. Moreover, many optically variable anti-counterfeiting elements that already exist have the same or similar angle-dependent color changing effect, which is easy to confuse the public. , providing opportunities for counterfeiters

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0065] Mix the following three kinds of liquid crystal molecules, chiral substances, photoinitiators, stabilizers and anisole in a certain proportion (as shown in Table 1) to make a homogeneous solution, and the concentration of the chiral substances is selected from the ones shown in Table 1. The lower part in the percentage range, such as 0.8-1.5wt%; the above-mentioned uniform solution of a certain concentration is coated on the transparent PET (substrate layer 1) with a wire rod, dried to remove the solvent, and then used in a nitrogen atmosphere with ultraviolet light. The dried coating is cured by light to obtain a cholesteric liquid crystal layer (first liquid crystal layer) 2; then the surface of the cholesteric liquid crystal layer 2 is fully coated with dark infrared reflective ink to form a dark background layer 3 , dried, eventually forming a structure such as Figure 5 The structure of the optically variable anti-counterfeiting element shown in this order is: subs...

Embodiment 2

[0076] Make cholesteric liquid crystal mixed solution in the same manner as in Example 1, adjust the ratio of chiral substance and three kinds of liquid crystal molecules, the concentration of chiral substance is selected from the higher part in the percentage range of Table 1, such as 3.0-5.0 wt%; on transparent PET (substrate layer) 1, coat cholesteric liquid crystal mixed solution with silk bar, make cholesteric liquid crystal layer (the first liquid crystal layer) 2; Then on the surface of cholesteric liquid crystal layer 2 Partially apply dark infrared absorbing ink to form a dark background layer 3, dry, and finally form a structure such as Figure 6-1 The structure of the optically variable anti-counterfeiting element shown in this order is: substrate layer 1 - first liquid crystal layer 2 - dark background layer 3 .

[0077] Observe the optically variable anti-counterfeit element with naked eyes at a vertical angle, and the reflected light in the area where the dark ba...

Embodiment 3

[0079] The nematic liquid crystal prepolymer material disclosed in US6291629, the chiral substance disclosed in WO9749694, the IRGACURE 369 photoinitiator of Ciba-Geigy Company, the stabilizer, anisole and cyclopentanone are mixed with each other to make a gallbladder Steroidal liquid crystal solution, adjust the concentration of chiral substance, prepare cholesteric liquid crystal solution 1 and cholesteric liquid crystal solution 2, wherein the concentration of chiral substance in cholesteric liquid crystal solution 1 is lower than that in cholesteric liquid crystal solution 2 The concentration of the active substance; Two kinds of cholesteric liquid crystal solutions are overprinted on the surface of transparent BOPP (substrate layer) 1 by gravure, cholesteric liquid crystal solution 1 forms region 311, cholesteric liquid crystal solution 2 forms region 312, dry The solvent is removed, and then the dried coating is cured with ultraviolet light under a nitrogen atmosphere to ...

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PUM

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Abstract

The invention provides an optically variable anti-counterfeiting element first, which at least has a first liquid crystal layer and a dark background layer, wherein the first liquid crystal layer is made of at least one cholesteric liquid crystal material, the dark background layer contains an anti-counterfeiting material which can be identified by machine reading, and at least part of dark background layer is overlapped with at least part of the first liquid crystal layer up and down to form an overlapped area; and when the overlapped area is observed at two set angles, the reflected light changes between a colorless state and a colored state. The optically variable anti-counterfeiting element provided by the invention has a primary anti-counterfeiting characteristic that reflected light of at least part of areas changes between a colorless state and a colored state with the change in an observation angle and secondary machine-reading anti-counterfeiting characteristics of infrared rays, magnetism, fluorescence, information hiding and the like, thereby allowing people to identify counterfeit easily and combining multi-stage anti-counterfeiting factors different to counterfeit. The invention also provides product with the optically variable anti-counterfeiting element.

Description

technical field [0001] The invention relates to an optically variable anti-counterfeiting element for protecting valuable items, in particular to an optically variable anti-counterfeiting element, which is viewed from different angles, and the color of at least some areas is interchangeable between colorless and colored and combined with machine-readable anti-counterfeiting features. Optical variable anti-counterfeiting element. Background technique [0002] With the development of modern duplication technology, counterfeiting crimes against all kinds of brand-name goods, financial instruments and securities are becoming more and more rampant. , some counterfeit securities have even reached the point where it is difficult to distinguish the real from the fake for the public, causing unnecessary confusion. The sophistication and extensiveness of counterfeiting technology have put forward higher requirements for anti-counterfeiting technology. [0003] At present, a variety ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G09F3/02B44F1/12B42D25/36B42D25/364
Inventor 刘卫东柯光明周基炜王斌周乐邓德斌刘东杨志洪
Owner CHINA BANKNOTE SECURITY PRINTING TECH RES INST CO LTD
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