Optical variable device

Optical variable device

An optical variable device or optically variable device (OVD) is an iridescent image that exhibits various optical effects such as movement or color changes.[1] OVDs cannot be photocopied or scanned, nor can they be accurately replicated or reproduced. The OVD is often used as a security device and anti-counterfeiting measure on money, credit cards and government issued identification cards. OVDs can be created through a combination of printing and embossing.

OVDs are based on diffractive optical structures. This gives cards the appearance of having different patterns, colors, and designs depending on the amount of light striking the OVD and the angle the OVD is viewed at. Holograms are a type of OVD.

References

  1. ^ "More about Optically Variable Devices (OVDs)" Product Authentication & Security Directory

Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Optical IP Switching — (OIS), is a novel method of creating transparent optical connections between network nodes using a flow based approach. An IP flow is a collection of IP packets going from the same source to the same destination: the exchange of IP packets is the …   Wikipedia

  • Optical modulators using semiconductor nano-structures — Contents 1 Optical modulators using semiconductor nano structures 1.1 Electro optic modulator of nano structures 1.2 Acousto optic modulator of nano structures …   Wikipedia

  • Optical attenuator — Variable Optical Attenuator An optical attenuator is a device used to reduce the power level of an optical signal, either in free space or in an optical fiber. The basic types of optical attenuators are fixed, step wise variable, and continuously …   Wikipedia

  • Device file — In Unix like operating systems, a device file or special file is an interface for a device driver that appears in a file system as if it were an ordinary file. There are also special device files in MS DOS and Microsoft Windows. They allow… …   Wikipedia

  • Device file system — In Unix like operating systems, a device file system or special file system allows software to interact with a device driver using standard input/output system calls, which simplifies many tasks.It includes device files , device nodes , or device …   Wikipedia

  • Optical disc drive — A CD/DVD ROM Drive A Blu ray (BD RE DL) writer tray in a Sony Vaio E series laptop …   Wikipedia

  • Optical buffer — In telecommunications, an optical buffer is a device that is capable of temporarily storing light. Just as in the case of a regular buffer, it is a storage medium that enables compensation for a difference in time of occurrence of events. More… …   Wikipedia

  • Optical chopper — An optical chopper is a mechanical device which periodically interrupts a light beam. Three types are available: variable frequency rotating disc choppers, fixed frequency tuning fork choppers, and optical shutters. A rotating disc chopper was… …   Wikipedia

  • Passive optical network — A passive optical network (PON) is a point to multipoint, fiber to the premises network architecture in which unpowered optical splitters are used to enable a single optical fiber to serve multiple premises, typically 32 128. A PON consists of an …   Wikipedia

  • semiconductor device — ▪ electronics Introduction       electronic circuit component made from a material that is neither a good conductor nor a good insulator (hence semiconductor). Such devices have found wide applications because of their compactness, reliability,… …   Universalium

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”