Optically Variable Devices describe both laser-generated hologram images and electron beam- generated images, and are authentication devices which are visible to the naked eye and show dynamic visual effects.

Created in highly-secure facilities and used in overt asset and brand protection initiatives, OVDs are applied to metallic substrates and activated by a laser source to form hologram-type images that allow manufacturers to communicate brand identity and keep it secure from counterfeiters.

Typical OVDs are diffractive elements or special inks. Overt features reduce the number of fakes in the market because the additional expenses are prohibitive to the counterfeiter. The main advantage of OVDs is the fast and easy on-the-spot authentication where no additional tools or machines are needed.