Kinetic diffraction grating
A kinetic diffraction grating is a type of diffraction grating designed to create dynamic optical effects, such as motion, colour shifts, or three-dimensional depth, when viewed at a different angle or if the incident light source changes. While traditional gratings are often used for static spectral analysis, kinetic gratings are found in security printing and holography.
Mechanism
Kinetic diffraction gratings function through the precise arrangement of microscopic pixels, each containing a specific grating structure. Unlike a uniform grating, these pixels vary in the density and angle of lines, which determines the wavelength and the viewpoints at which light becomes visible to the observer.[1]
As the substrate is tilted or rotated, different sets of grating pixels sequentially diffract light toward the viewer's eye. This sequential activation creates the perception of movement, such as a rotating bar, an expanding shape, or a pump effect where colours appear to flow across the image.[2]
Types and applications
The most common use of kinetic gratings is in the production of Optically Variable Devices (OVDs), often found on banknotes, passports and credit cards in order to prevent counterfeiting.[3] Since these gratings require sophisticated electron-beam or laser record systems to manufacture, it becomes more difficult for counterfeiters to replicate using standard methods.[4]
See also
References
- ↑ Kim, Youngji; Hyun, Jerome K. (2023-06-19). "Encoding Mie, plasmonic, and diffractive structural colors in the same pixel". Nanophotonics (Berlin, Germany). 12 (16): 3341–3349. doi:10.1515/nanoph-2023-0254. ISSN 2192-8614. PMC 11501730 Check
|pmc=value (help). PMID 39634150 Check|pmid=value (help). - ↑ Yu, J., Pei, W., & Hsu, D. (1996, December). Pixel encoding technique for generating kinetic diffraction grating images. In G. Mu, G. Jin, & G. T. Sincerbox (Eds), International Conference on Holography and Optical Information Processing (ICHOIP 1996) (pp. 222–226). doi:10.1117/12.263079
- ↑ Bakanas, Ramunas; Bulanovs, Andrejs; Zacharovas, Stanislovas J. (2018-02-19). Bjelkhagen, Hans I.; Bove, V. Michael, eds. "New diffractive effects for security holograms produced with Geolas Originators". Practical Holography XXXII. SPIE: 39. doi:10.1117/12.2312719. ISBN 978-1-5106-1601-1.
- ↑ "Secure Hologram Technology: Strengths and Limitations". www.kinegram.com. Retrieved 2026-03-02.
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