HOLOGRAM

A diffractive optically variable device. Optical properties of the hologram are defined in terms of diffraction of light going through a diffraction grating. Optical effects occur when changing the angle of observation or illumination. Holograms may contain nano-, microprinting, microimages, covert laser readable images, etc.

Classification of holograms by optical properties:

  1. Reflection holograms form an image in reflected light. Aluminum foil or a transparent dielectric which reflects not more than 10-20% of light (transparent hologram) are used as a reflection layer.

  2. Transmission holograms form an image in transmitted light.

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b — Holograms over the whole document page; c — Diffractive identification device; d — Microtext 


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 b, c, d — Zoomed fragment. View at different angles of observation

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a — visa in the form of a sticker; b, c — View at different angles of observation; d — Nanotext (zoomed fragment of the letter K)


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