LCD projector

These lamps also have the ability to produce an extremely large amount of light within a small area; current projectors average about 2,000 to 15,000 American National Standards Institute (ANSI) lumens.

Other technologies, such as Digital Light Processing (DLP) and liquid crystal on silicon (LCOS) are also becoming more popular in modestly priced video projection.

Even so, the best image quality is found using a blank white, grey, or black[citation needed] (which blocks reflected ambient light) surface, so dedicated projection screens are often used.

[3] As direct-driven, passive LCDs (without thin-film transistors) at the matrix intersections) were not capable of displaying images with sufficient resolution for video pictures, a combination of a fixed image together with an LCD matrix for the variable elements was proposed as an LC projector for certain control room applications,[4] with a corresponding patent filed in Switzerland on Dec. 3, 1971.

After building it, he saw many problems that had to be corrected including major light losses and very noticeable pixels (sometimes referred to as the "screen-door effect").

At about the same time, the German company "Bonner Ingenieurbüro für Optoelektronik CrystalVision" started experimenting with LCD projection devices from 1985 onwards.

Bernt Haastert, an engineer working at CrystalVision, found out, that placing the required polarizing filters at a certain distance on both sides of the LC cell allowed for efficient air cooling of the arrangement.

Early pioneers of LCD projection in Japan were Epson and Sharp,[8] which launched their own color video projector products in 1989.

The LCD system did not have a light source of its own: it was built on a large "plate" that sat on top of the projector in place of transparencies.

This provided a stop-gap solution in the era when the computer was not yet a universal display medium, creating a market for LCD projectors before their current main use became popular.

In 2004 and 2005, LCD front projection began a comeback with the introduction of the dynamic iris and other modifications that have improved perceived contrast to levels similar to DLP.

The basic design of an LCD projector is frequently used by hobbyists who build their own DIY (do-it-yourself) projection systems.