NEW DELHI: The once humble video projector may be now giving Plasma TVs a run for their money, with pin-head clarity of high contrast pictures to get an image that goes far beyond the 42" Plasma screen… Optoma, the manufacturers of the latest DLP say home screens ca now go up to 200 inches!

Up until now, in recent years LCDs and Plasma TVs had been the rage, but now, a reinvented technology has arrived on the scene that may change the whole big screen TV concept forever. It is the DLP, or Digital Light Processing.

The key to DLP is the DMD (Digital Micro-mirror Device).

In essence, every pixel on a DLP chip is a reflective mirror, which amplifies the light generated from the chip.

Since the light generated by each pixel has its own amplification ability, there is no limit to the size of the screen that can be manufactured. Brightness and contrast is even across the entire surface of the screen.

The advantage of DLP is two-fold:
* It produces bright, high-contrast images, viewable from a wide angle, and (2) It can be projected onto any size screen (from home theater setups to movie theater setups), with equal image quality; and
* With the advent of HDTV, DLP is the best option for reproducing high-resolution projected images.

On the industrial front, DLP is being used in large projection screen applications such as concert venues and movie theaters.

Several films have been released to special take advantage of DLP projection technology, including: Star Wars: Episode I, Mission To Mars, Toy Story 2, Rocky and Bullwinkle, Disney‘s Dinosaur, and Spy Kids.

In a recent BBC feature on its technology programme, Click, it said that domestic video projectors come in two different flavours: LCD or DLP.

The brainchild of Texas Instruments, Digital Light Processing (DLP) first appeared 20 years ago. In video projectors the key to DLP are optical semiconductors covered in millions of tiny mirrors.

These mirrors reflect light which is projected onto them, and each mirror represents an individual pixel. The higher the resolution the more mirrors are required.

Bob Johnson of Optoma told BBC‘s Click on April 16: "It‘s a digital device, whereas the majority of the other technologies are all analogue devices. So if you‘re using an HD DVD player or your normal home DVD player, that‘s a digital device, you get a digital image on your screen."

There is one drawback to DLP technology.

In order for the chips to produce colour images, a spinning wheel fitted with coloured filters is placed in front of the chip. When this wheel spins it can create an effect which looks like rainbow patterns appearing around the pixels. This can be a bit irritating.

LCD projectors don‘t enjoy the same level of contrast or dark blacks that DLPs produce, and up close some individual pixels can be visible as squares. There is however a price difference - many LCD projectors are cheaper than their DLP counterparts.

Improvements in lamp technology mean that a wide variety of the bulbs that are fitted to the current generation of video projectors are so bright they can viewed in almost daylight conditions.

And as LCD screens have embraced HD 1080P resolution so to have video projectors. So it‘s possible to use projectors in rooms that aren‘t as dark as your local multiplex - and with HD support, movies, TV and video games now look pin sharp.

But if you‘re planning to ditch the TV in favour of a projector what sort of features should you be looking out for?

Picture size is altered by the distance the projector is away from the screen, known as ‘throw‘. As a rule of thumb about 10ft away from a wall or a screen will produce an image of 100 inches.

It‘s important to select a projector and bulb which can produce a sufficient amount of light to work in a domestic setting. Known as the lumen value, this allows you to know how bright a bulb is. For a room which has ambient lighting in it a bulb which produces in excess of 1200 lumens will be required.

Projectors used to make more noise than a normal TV due to fans that are needed to cool the unit down. Although modern projectors are considerably quieter than their forebears, fan noise is still evident.

The biggest drawback is the cost of replacement lamps. Lamps usually last around 2000 to 3000 hours, but after that it‘s time for a new one and this can be expensive, in some cases up to ?400. But overall prices of domestic projectors have dropped. It‘s possible to get a DLP HD -ready projector for around ?700, which compares favourably with large LCD or Plasma screens.

Great big video projectors are fine if you‘ve got a great big home to put them in, but if there‘s a shortage of space a tiny little DLP projector can provide a solution to the problem.

And as laser technology becomes introduced to projectors they are going to get even smaller.

There is a company in the United States that‘s developing a projector which is so small it will fit inside a mobile phone.