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Comparing Rear-Projection Display Technologies -- Part 1AP/LCD, polysilicon LCD and DLP have important differences
In 1997, the first digital rear-projection display system was brought to market and soon afterward was followed by advancements in applications of established technologies, such as integrating amorphous liquid crystal display (AM-LCD) into the design of rear projection display systems.
Further technological advances, as well as the decline of component prices, continued to fuel new innovation by various display manufacturers. These included the development of new applied technologies such as AP/LCD, the creation by Texas Instruments Corporation, of Digital Light Processing (DLP), the introduction of polysilicon LCD technology to rear projection, advances in plasma technology and new larger direct view AM-LCD panels. All these have energized the pro-AV industry by providing new rear-projection presentation product choices for business or consumer applications.
Today, customers demand, and can take advantage of, the newest, highest quality, highest resolution digital displays for their command centers, conference rooms, presentation rooms, control rooms, network operations centers, and retail signage environments. However, with so many different applications and an expanding variety of display technology choices, it is important to understand which technology is best for a particular application. This article outlines the differences between AP/LCD, which uses amorphous LCD, polysilicon LCD, and DLP technology in rear-projection displays.
LCD technologies are not all the same
Presently there are two well-established LCD technologies. Amorphous thin film transistor LCD (AM-LCD) is used in millions of laptop computers, computer games and other well known electronic devices. HTPS-LCD, also known as polysilicon LCD, was developed for and is widely used in portable presentation projectors. A third type, Liquid Crystal on Silicon (LCoS) has yet to reach broad adoption into presentation equipment markets and therefore will not be addressed in this article.
There have been numerous studies published regarding these different LCD technologies. One such study, entitled, Reliability of HTPS Panels Questioned,1 compares DLP projection technology to polysilicon LCD projection technology. This study contains key performance characteristics showing that DLP has advantages over polysilicon LCD technology. However it should not be used as a reference document for all LCD display technology.
The reason is that while the intent of this study was to compare and contrast the differences between DLP and polysilicon LCD, in my opinion, it has served to confuse some buyers about LCD technology in general, leading them to believe that the pitfalls of polysilicon LCD are to be found across all LCD technology. After this study was published, it became clear that what was needed was clarification about the differences between AP/LCD and polysilicon LCD, as well as an explanation of how these two LCD technologies compare to DLP in rear-projection systems.
Related Keywords:rear-projection technologies, LCD vs. DLP, digital display industry
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