Diffractive optically variable image device

A diffractive optically variable image device (DOVID) is a type of optical variable device; a security feature based on visual effects created by diffraction. The acronym was coined by Ian Lancaster of Reconnaissance International in 1995.[1] He pointed out that the security print industry was wary of holograms and similar diffractive devices because they were used as decorative, promotional and toy items, proposing the use of DOVID as a means to differentiate security diffractive optical devices from these other uses.

DOVIDs are incorporated in government-issued documents of value (banknotes, passports, visas, identification credentials and driver licenses) to increase their counterfeit resistance.[2][3] Brand protection is another application of DOVIDs. DOVIDs contain micro- or nanostructures in the form of diffractive gratings. Due to these structures, they exhibit optically variable effects such as dynamic chromatic, holographic, and kinematic effects, two- or three-dimensional images or color-changing effects, which ideally are easily recognized, but are difficult to reproduce. Well known examples of DOVIDs are holograms such as 2D or 3D or 2D/3D holograms based on mask illumination, dot matrix or e-beam origination technology and Kinegrams.[4][5][6]

A DOVID can also contain elements which are invisible to the unaided human eye such as microprint, kinetic microtext, or a variable laser-readable micro-image that is invisible when magnified under white light. DOVID structures can be incorporated in a foil: which is then hot stamped on a paper document (e.g., banknote, visa), incorporated within the structure of a polycarbonate or composite card (e.g., passport, driver licenses) before personalization or integrated in a laminate that is heat sealed to the surface of a card after personalization (e.g., driver licenses, identity cards).[7]

  1. ^ Lancaster, Ian (1995). Diffractive Optically Variable Image Devices. Intergraf International Security Printers Conference. Lisbon.
  2. ^ Stole, Svorad; Soukup, Daniel; Huber-Mörk, Reinhold (September 2015). "Invariant characterization of DOVID security features using a photometric descriptor". 2015 IEEE International Conference on Image Processing (ICIP). pp. 3422–3426. doi:10.1109/ICIP.2015.7351439. ISBN 978-1-4799-8339-1. S2CID 12289666.
  3. ^ "Document Security Alliance (DSA)". Archived from the original on 2011-06-29. Retrieved 2021-05-05.
  4. ^ "Council of the European Union – PRADO – Public Register of Authentic Identity and Travel Documents". Archived from the original on 2016-09-24. Retrieved 2021-05-05.
  5. ^ van Renesse, R. L. (2005). Optical Document Security. Boston, London: Artech House.
  6. ^ Cabral, Alexandre; Rebordão, José M. (2011-07-26). "Diffractive optical variable image devices generated by maskless interferometric lithography for optical security". In Costa, Manuel F (ed.). International Conference on Applications of Optics and Photonics. Vol. 8001. International Society for Optics and Photonics. p. 800121. Bibcode:2011SPIE.8001E..21C. doi:10.1117/12.890750. S2CID 108645721.
  7. ^ "Technical terms related to security features and to security documents in general" (PDF). Archived (PDF) from the original on 2015-09-24. Retrieved 2021-05-05.