Polaroid

Polaroid (a trademark of the Polaroid Corporation) is the name of a type of synthetic plastic sheet which is used to polarise light.

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The original material, patented in 1929 () and further developed in 1932 by Edwin H. Land, consists of many microscopic crystals of iodoquinine sulphate (herapathite) embedded in a transparent nitrocellulose polymer film. The needle-like crystals are aligned during manufacture of the film by stretching or by applying electric or magnetic fields. With the crystals aligned, the sheet is dichroic: it tends to absorb light which is polarised perpendicularly to the direction of the crystal alignment, but transmits light which is polarised parallel to it. This allows the material to be used as a light polariser.

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This material, known as J-sheet, was later replaced by the improved H-sheet Polaroid, invented in 1938 by Land. H-sheet is a polyvinyl alcohol (PVA) polymer impregnated with iodine. During manufacture, the PVA polymer chains are stretched such that they form an array of aligned, linear molecules in the material. The iodine dopant attaches to the PVA molecules and makes them conducting along the length of the chains. Light polarised parallel to the chains is absorbed, and light polarised perpendicular to the chains is transmitted.

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Polaroid sheets are used in liquid crystal displays, optical microscopes and sunglasses.

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Polaroid is also used as a trade name for a variety of products sold by the Polaroid Corporation, including sunglasses based on Polaroid polarisers, and instant-print photographic film and cameras.

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Trademark: A trademark (Commonwealth English: trade mark) is a distinctive sign of some kind which is used by a business to identify itself and its products and services to consumers, and to set the business and its products or services apart from those of other businesses. A trademark is a type of intellectua...

Polaroid Corporation: The Polaroid Corporation was founded in 1937 by Edwin H. Land. It is most famous for its instant film cameras, which reached the market in 1948, and continue to be the company's flagship product line. The company's original dominant market was in polarized sunglasses, an outgrowth of Land's self-gui...

Plastic: Plastic is a term that covers a range of synthetic or semisynthetic polymerization products. They are composed of organic condensation or addition polymers and may (often) contain other substances to improve performance or economics. There are few natural polymers generally considered to be "pla...

Polaroid related Images and Photos (experimental)

Jason Mraz - Polaroid	Perfect Couples Polaroid Mug	Justin Bieber Polaroid Youth T-Shirt	Women's: Bruno Mars - Polaroid
Film Director Stanley Kubrick Holding Polaroid Camera During Filming of "2001: A Space Odyssey"