Friday, 2 March 2012

Difference Between LCD & DLP Projector



The Technical Differences between LCD and DLP 

LCD (liquid crystal display)
 projectors usually contain three separate LCD glass panels, one each for red, green, and blue components of the image signal being fed into the projector. As light passes through the LCD panels, individual pixels ("picture elements") can be opened to allow light to pass or closed to block the light, as if each little pixel were fitted with a Venetian blind. This activity modulates the light and produces the image that is projected onto the screen.

DLP ("Digital Light Processing") is a proprietary technology developed by
 Texas Instruments. It works quite differently than LCD. Instead of having glass panels through which light is passed, the DLP chip is a reflective surface made up of thousands of tiny mirrors. Each mirror represents a single pixel.

In a
 DLP projector
, light from the projector's lamp is directed onto the surface of the DLP chip. The mirrors wobble back and forth, directing light either into the lens path to turn the pixel on, or away from the lens path to turn it off.

In very expensive DLP projectors, there are three separate DLP chips, one each for the red, green, and blue channels. However, in DLP projectors under $20,000(90,000 Rs approx), there is only one chip. In order to define color, there is a color wheel that consists of red, green, blue, and sometimes white (clear) filters. This wheel spins between the lamp and the DLP chip and alternates the color of the light hitting the chip from red to green to blue. The mirrors tilt away from or into the lens path based upon how much of each color is required for each pixel at any given moment in time. This activity modulates the light and produces the image that is projected onto the screen.
source(s): http://www.projectorcentral.com

Thursday, 1 March 2012


 4 Main things while buying a Projector     

1). There are 3 types of projector - LCD, DLP, CRT

2). The Lumens output (brightness) of lamp - 800-1000 is good for LCD, DLP at 1000 is good. Dont get it to high or colours will look poor, less than 1500 is really needed for good colour reproduction.

3). The Resolution. For optimal picture make sure to get XGA or WXGA. A cheaper method is VGA/SVGA, but if you can get XGA or higher you wont regret the moeny spent.

4). A very key point is contrast ration. 300:1 and less is poor meaning blacks look dark grey. 700:1 and higher is good giving darker blacks and whiter whites (contrast is difference between these two). 1000:1 + is excellent.  (source:  http://www.afterdawn.com/ )

History about LCD Projectors


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 3-CRT 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.


Currently[when?] 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). This is not expected to have much longevity in the home-theater marketplace due to expected improvements in cost and performance of competing technologies, particularly in direct-view LCD panels at the lower range of sizes and DLP projection in the larger sizes.[citation needed] 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 currently[when?] 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.[citation needed] 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.

Meaning for Projector



Pronounciation for  projector - pro·jec·tor  


Noun form : An object used to project rays of light, esp. an apparatus with a system of lenses for projecting slides or film onto a screen.A person who plans and sets up an enterprise.

Thursday, 23 February 2012

hi my name is Altamash Qureshi n m nu to this blog hope to continue wid projector demo 

Intresting Fact

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Welcome to Projector World this is demo video that i would like to show you