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Overhead projectors were used early on for police work with a cellophane roll over a 9-inch stage, allowing facial characteristics to be rolled across the stage. [ citation needed ] As the demand for projectors grew, Buhl Industries was founded in 1953, and became the leading US contributor for several optical refinements for the overhead ...
Before phones were pocket-sized supercomputers, people had to stop if they wanted to make calls on the go. ... Yi Xing invented the first known alarm clock, ... Overhead Projectors. Early 1960s-2015
Video projectors are digital replacements for earlier types of projectors such as slide projectors and overhead projectors. These earlier types of projectors were mostly replaced with digital video projectors throughout the 1990s and early 2000s, [ 1 ] but old analog projectors are still used at some places.
Invented by 3M in the early 1960s, overhead projectors and transparencies quickly became a core teaching tool in classrooms across the country. But 3M discontinued its iconic product in 2015.
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.
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.
35mm filmstrip projectors; Overhead presentation projectors (all models) Stereo cameras and stereo slide projectors through its TDC subsidiary; Slide Cube Projector, circa 1970; In 1934, Bell & Howell introduced their first amateur 8mm movie projector, in 1935 the Filmo Straight Eight camera, and in 1936 the Double-Run Filmo 8.
To market 3LCD projector technology, Epson also set up a consortium called the "3LCD Group" in 2005 with other projector manufacturer licensees of 3LCD technology that use it in their projector models. Early LCD systems were used with existing overhead projectors.