LCD Projector - History

History

The LCD projector was invented by American inventor Gene Dolgoff. He began working on it in college in 1968 as a way to produce a video projector that would be brighter than the then-available 3CRT projectors. The idea was to use an element referred to as a "light valve" to regulate the amount of light that passes through it. This would allow the use of a very powerful external light source. After trying many different materials, he settled on liquid crystals to modulate the light in 1971.

It took him until 1984 to get an addressable LCD, which is when he built the world's first LCD projector. 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"). He then invented new optical methods to create high efficiency and high-brightness projectors (now used in most digital projectors) and invented depixelization to eliminate the appearance of the pixels.

With patents all around the world (filing the first LCD projector patent application in 1987), he started Projectavision, Inc. in 1988, the world's first LCD-projector company, which he took public on Nasdaq in 1990. He licensed the technology to other companies including Panasonic and Samsung. This technology and company started the digital-projection industry.

In 1989, he was awarded the first Defense Advanced Research Projects Agency (DARPA) contract – for US$1 million – for proposing that the United States high-definition television (HDTV) standard should use digital processing and projection. As a member of the National Association of Photographic Manufacturers Standards Subcommittee, IT7-3, he along with Leon Shapiro, co-developed the worldwide ANSI standard for measurement of brightness, contrast, and resolution of electronic projectors.

Since 2005, the only remaining manufacturers of the LCDs for LCD projectors are Japanese imaging companies Epson and Sony. Epson owns the technology and has branded it as "3LCD". 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. 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 the transparencies. This provided a stop-gap solution in the era when the computer was not yet the universal display medium, creating a market for LCD projectors before their current main use became popular.

This technology is employed in some sizes of rear-projection television consoles, as there are cost advantages when employed in mid-size sets (40- to 50-inch diagonal). Another advantage of using this LCD-projection system in large television sets is to allow better image quality as opposed to a single sixty-inch television, although in 2006, an equal of an LCD projector is the LG 100-inch LCD TV, still in prototype stages this television is a huge advancement towards projector-sized televisions. A common rule of thumb is that an LCD's image quality will decrease with a size increase. A workaround is to use a small LCD panel (or panels) and project them through a lens onto a rear-projection screen to give a larger screen size with a decreased contrast ratio, but without the quality loss.

In 2004 and 2005, LCD front projection was enjoying a come-back because of the addition of the dynamic iris which has improved perceived contrast up to the levels of DLP.

The basic design of an LCD projector is frequently used by hobbyists who build their own DIY (do-it-yourself) projection systems. The basic technique is to combine a high color-rendering index (CRI) high-intensity discharge lamp (HID lamp) and ballast with a condenser and collector Fresnel lens, an LCD removed from a common computer display and a triplet lens.