Paper
3 June 2004 Multilayer polymeric color-shifting polarizer films
James M. Jonza, Andrew D. Dubner
Author Affiliations +
Proceedings Volume 5310, Optical Security and Counterfeit Deterrence Techniques V; (2004) https://doi.org/10.1117/12.527067
Event: Electronic Imaging 2004, 2004, San Jose, California, United States
Abstract
Color-shifts have been used in the field of optical security for many years. Through the use of birefringent polymers, 3M has pioneered highly reflective, multilayer, all-polymeric interference optical films for use as mirrors and polarizers. Polarizer and mirror multilayer films with reflectance bands covering all of the visible wavelengths have found uses in LCD displays and solar light pipes. Color-shifting polarizer (CSP) films may be made by uniaxially orienting a multilayer stack that has sharp band edges and does not cover all of the visible wavelengths. By judicious choice of polymers, the refractive indices of the two polymers have a large difference in refractive index in the stretch direction and match in the transverse direction. The resulting film has a noticeable color shift to the unaided eye, and a readily verifiable feature when viewed with both polarization states. In the pass condition, the film becomes colorless; in the block direction, the color is very saturated and noticeably shifts in hue when the viewing angle is changed. The films may have reverse printing under the CSP films, which hides during verification. The indelible marking of the film for the intended end use and the tamper resistance of labels made from these films will also be discussed.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
James M. Jonza and Andrew D. Dubner "Multilayer polymeric color-shifting polarizer films", Proc. SPIE 5310, Optical Security and Counterfeit Deterrence Techniques V, (3 June 2004); https://doi.org/10.1117/12.527067
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Cited by 3 scholarly publications and 11 patents.
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KEYWORDS
Polarizers

Photography

Polymers

Refractive index

Reflectivity

Multilayers

Mirrors

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