Semiconductor Physics, Quantum Electronics & Optoelectronics. 2006. V. 9, N 4. P. 085-090.
https://doi.org/10.15407/spqeo9.04.085


Kinoform synthesis as an improved method to form a concealed image in optical security devices
Eu. Braginets1, V. Girnyk2, S. Kostyukevych3, V. Kurashov1, N. Moskalenko3, A. Soroka1

1Taras Shevchenko Kyiv National University (Ukraine) 2Optronics (Ukraine) 3V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine (Ukraine)

Abstract. It is well known that one of the basic functions of security holograms is the maximal complication of their non-authorized reproduction, in other words – counterfeiting. To solve the problem, concealed images that can be observed only under special conditions are placed into a structure of the hologram. A popular way to place concealed image in Diffractive Optically Variable Image Device (DOVID) is integration into DOVID's structure of a Concealed Laser-Readable Image (CLRI). Traditionally CLRI is a 2D Computer-Generated Hologram (2D CGH), which is a digitized Interference Fringe Data (IFD) structure, computed under the scheme of Fourierhologram synthesis. Such hologram provides inspection of the second level with portable laser reading devices. While it is being read, two (+/– 1 order of diffraction) identical images are formed. It is very interesting to achieve a CGH, which restores the image only in one diffractive order or two different images in +1 and –1 orders of diffraction.

Keywords: concealed image, kinoform methods, 2D CGH, CLR.

Full Text (PDF)

Back to N4 Volume 9