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An overhead projector works on the same principle as a slide projector, in which a focusing lens projects light from an illuminated slide onto a projection screen where a real image is formed. However some differences are necessitated by the much larger size of the transparencies used (generally the size of a printed page), and the requirement ...
View history; General ... Pages in category "Projectors" ... Polylux (overhead projector) Profile Projector; Projection booth; Projector camera systems;
A Projection panel (also called overhead display [1] or LCD panel [2]) is a device that, although no longer in production, was used as a data projector is today. It works with an overhead projector. The panel consists of a translucent LCD, and a fan to keep it cool.
In the late 1950s and early 1960s, overhead projectors began to be widely used in schools and businesses. The first overhead projector was used for police identification work. [citation needed] It used a celluloid roll over a 9-inch stage allowing facial characteristics to be rolled across the stage. The United States military in 1940 was the ...
In the GDR, it was mainly known for producing overhead projectors, called Polylux. The company was founded in 1870 as Reißzeugrichter and manufactured drawing table tools. In 1874 the founder Emil Oskar Richter invented the bow compass. After switching its focus to overhead projectors in the late 1960s, it was renamed to VEB Polytechnik.
Second, American shows were generally built around the overhead projector with the liquids in large clock cover glasses. Shows in England and Europe, in contrast, used modified 2" sq. slide projectors which had their dichroic heat filters (one or both) removed and employed two three or even four layers of slide cover glasses with one or two ...
The Polylux was an overhead projector produced in the German Democratic Republic (GDR). It also functioned as a generic name for overhead projectors in the GDR. The Polylux was produced in the VEB ( Volkseigener Betrieb : people’s enterprise) Phylatex-Physikgeräte DDR, in Frankenberg near Chemnitz (then known as Karl-Marx-Stadt ).
Overhead projector in operation, with a transparency being flashed. A transparency, also known variously as a viewfoil or foil (from the French word "feuille" or sheet), or viewgraph, is a thin sheet of transparent flexible material, typically polyester (historically cellulose acetate), onto which figures can be drawn.