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Optically Variable Device
An optical variable device or optically variable device (OVD) is an iridescent or non-iridescent security feature that exhibits different information, such as movement or colour changes, depending on the viewing and/or lighting conditions. The particular changes of appearance when rotating and tilting are reversible, predictable and reproducible. OVDs cannot be photocopied or scanned, nor can they be accurately replicated or reproduced. OVDs are often used as security devices and anti-counterfeiting measures on banknotes, government-issued identification documents, or credit cards. OVDs can be created through a combination of printing Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The ea ... and embossing. OVDs are based on diffractive optical structures. This gives cards the appearance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OVD Patch 500 Pesos
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OVD may refer to: *OVD, IATA airport code for Asturias Airport, Asturias, Spain *ovd, ISO 639-3 code for Elfdalian, a North Germanic language spoken in Sweden *Online video distributor, also known as over-the-top media services *Optical Variable Device, an iridescent image that exhibits various optical effects such as movement or color changes * Ophthalmic Viscosurgical Device, a viscoelastic solution used in eye surgery *Oracle Virtual Directory, a component of Oracle Fusion Middleware *Old Vatted Demerara, a brand of rum distilled by William Grant & Sons William Grant & Sons Ltd is an independent, family-owned Scottish company that distills Scotch whisky and other selected categories of spirits. It was established in 1887 by William Grant, and is run by Grant's descendants as of 2018. It is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridescent
Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterfly wings and seashell nacre, and minerals such as opal. It is a kind of structural coloration that is due to wave interference of light in microstructures or thin films. Pearlescence is a related effect where some or most of the reflected light is white. The term pearlescent is used to describe certain paint finishes, usually in the automotive industry, which actually produce iridescent effects. Etymology The word ''iridescence'' is derived in part from the Greek word ἶρις ''îris'' ( gen. ἴριδος ''íridos''), meaning ''rainbow'', and is combined with the Latin suffix ''-escent'', meaning "having a tendency toward". Iris in turn derives from the goddess Iris of Greek mythology, who is the personification of the rainbow and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photocopier
A photocopier (also called copier or copy machine, and formerly Xerox machine, the generic trademark) is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopiers use a technology called ''xerography'', a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles (a powder) onto paper in the form of an image. The toner is then fused onto the paper using heat, pressure, or a combination of both. Copiers can also use other technologies, such as inkjet, but xerography is standard for office copying. Commercial xerographic office photocopying was introduced by Xerox in 1959, and it gradually replaced copies made by Verifax, Photostat, carbon paper, mimeograph machines, and other duplicating machines. Photocopying is widely used in the business, education, and government sectors. While there have been predictions that photocopiers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Image Scanner
An image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting or an object and converts it to a digital image. Commonly used in offices are variations of the desktop ''flatbed scanner'' where the document is placed on a glass window for scanning. ''Hand-held scanners'', where the device is moved by hand, have evolved from text scanning "wands" to 3D scanners used for industrial design, reverse engineering, test and measurement, orthotics, gaming and other applications. Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical. Modern scanners typically use a charge-coupled device (CCD) or a contact image sensor (CIS) as the image sensor, whereas ''drum scanners'', developed earlier and still used for the highest possible image quality, use a photomultiplier tube (PMT) as the image sensor. A ''rotary scanner,'' used for high-speed documen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Counterfeiting
To counterfeit means to imitate something authentic, with the intent to steal, destroy, or replace the original, for use in illegal transactions, or otherwise to deceive individuals into believing that the fake is of equal or greater value than the real thing. Counterfeit products are fakes or unauthorized replicas of the real product. Counterfeit products are often produced with the intent to take advantage of the superior value of the imitated product. The word ''counterfeit'' frequently describes both the forgeries of currency and documents as well as the imitations of items such as clothing, handbags, shoes, pharmaceuticals, automobile parts, unapproved aircraft parts (which have caused many accidents), watches, electronics and electronic parts, software, works of art, toys, and movies. Counterfeit products tend to have fake company logos and brands, which results in patent or trademark infringement in the case of goods. They also have a reputation for being lower quality, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printing
Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The earliest known form of printing as applied to paper was woodblock printing, which appeared in China before 220 AD for cloth printing. However, it would not be applied to paper until the seventh century.Shelagh Vainker in Anne Farrer (ed), "Caves of the Thousand Buddhas", 1990, British Museum publications, Later developments in printing technology include the movable type invented by Bi Sheng around 1040 AD and the printing press invented by Johannes Gutenberg in the 15th century. The technology of printing played a key role in the development of the Renaissance and the Scientific Revolution and laid the material basis for the modern knowledge-based economy and the spread of learning to the masses. History Woodblock printing Woodblock p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embossing (paper)
Embossing and debossing are the processes of creating either raised or recessed relief images and designs in paper and other materials. An embossed pattern is raised against the background, while a debossed pattern is sunken into the surface of the material but might protrude somewhat on the reverse side. Techniques Often used in combination with foil stamping, embossing alters the surface of paper stock or other substrates by providing a three-dimensional or raised effect on selected areas. The procedure requires the use of two dies: one that is raised and one that is recessed. The dies fit into each other so that when the paper is pressed between them, the raised die forces the stock into the recessed die and creates the embossed impression. A specific level of pressure is applied to the dies in order to squeeze the fibers of the paper, which results in a permanently raised area in the paper. When the dies are produced, a die maker engraves the desired image into several me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffractive
Diffraction is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a secondary source of the propagating wave. Italian scientist Francesco Maria Grimaldi coined the word ''diffraction'' and was the first to record accurate observations of the phenomenon in 1660. In classical physics, the diffraction phenomenon is described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets. The characteristic bending pattern is most pronounced when a wave from a coherent source (such as a laser) encounters a slit/aperture that is comparable in size to its wavelength, as shown in the inserted image. This is due to the addition, or interference, of different points on the wavefront (or, equivalently, each wavelet) that travel by paths of diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holography
Holography is a technique that enables a wavefront to be recorded and later re-constructed. Holography is best known as a method of generating real three-dimensional images, but it also has a wide range of other applications. In principle, it is possible to make a hologram for any type of wave. A hologram is made by superimposing a second wavefront (normally called the reference beam) on the wavefront of interest, thereby generating an interference pattern which is recorded on a physical medium. When only the second wavefront illuminates the interference pattern, it is diffracted to recreate the original wavefront. Holograms can also be computer-generated by modelling the two wavefronts and adding them together digitally. The resulting digital image is then printed onto a suitable mask or film and illuminated by a suitable source to reconstruct the wavefront of interest. Overview and history The Hungarian- British physicist Dennis Gabor (in Hungarian: ''Gábor Déne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
