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The common question heard when purchasing a new projector for the home, office, or classroom is: would I get an LCD projector or a DLP projector? LCD, an acronym for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many company brands and different types available, it can be challenging for the buyer to make a choice between those technologies. The fact is that LCD projectors give far superior image quality and colour accuracy. The article below explains why DLP projectors struggle with reproducing a comparable standard of image quality.

Visualise a set of blinds in your home over your bedroom window. With the twist of a rod you can have the shutters open or closed, according to if you want to let light in or not. And this is exactly how an LCD projector operates. Each pixel operates like an individual shutter on a set of blinds to either send light through or to block it. DLP on the other hand is formed of millions of microscopic mirrors or ‘pixel elements’ as the professionals like to call them. Each pixel element functions to either reflect light or block it.

How the light source is processed from the point at which the projector is switched on to when the image reaches your screen is extremely significant for image quality, brightness and colour accuracy. LCD projectors shine white light from the lamp by separating it into red, blue and green components, by three mirrors which direct the coloured light to 3 stand alone LCD panels. The 3 LCD panels create the elements of the image by shining each pixel on and off. The pixels are then projected in a glass prism to create the projector image. Something to remember about LCD projectors is that all three colours are projected onto your wall simultaneously. The way a DLP projector runs is vastly different and even the way an image comes out is not the same. With DLP, white light from the lamp is projected through a turning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of making an image casts a sequence of red, blue and green light. The millions of micro mirrors as mentioned above reflect the coloured light on the pixels to form the image elements. The elements of the image are projected in sequence on the screen, one colour at a time. The viewer’s eye will then pull together each coloured element of the image into the total image. From LCD projectors, all colours are available all the time to form high brightness and spectacular colour accuracy. In DLP, only one colour is available at any given time, resulting in lower colour brightness and accuracy. Some DLP designers have included a white segment into the colour wheel to improve brightness overall, but this goes and damages colour accuracy.

I read in forums all the time that DLP offers a higher contrast ratio and thus must be better quality. For those unaware, the contrast ratio is a measure of a display system defined as the ratio of the luminance of the brightest white to that of the darkest black that the technology is able to produce. DLP projectors do offer high contrast specifications when compared to the majority of LCD projectors. At a glance, this appears to be a benefit, however, in truth, the true black level is determined by the ambient light in the room while the projector is utilised. Do not be fooled by contrast specifications on websites and in brochures.

When the content you are trying to see has moving images, DLP projection technology can also create image imperfections, or ‘artifacts’. The most commonplace artifact that a DLP projector forms with moving images is colour break up. Colour break up is to be expected in DLP systems because moving images change up between the time red, blue and green colours are displayed. LCD projectors do not have this problem because all the colours are delivered simultaneously. DLP builders have come up with 3DLP solutions using 3 chips to answer the colour break up artifacts, but the price of these projectors make them not practical for most businesses and consumers.

Another differentiation between LCD and DLP is how they match the balance for the refractive qualities of light. Take yourself back to high school science, and recall when they taught you how different colours of light refract varied amounts when projected through the same lens. The disadvantage with DLP projectors is that they take the one same panel and the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light in a different way. Most of the time with a DLP projector, a spill of yellow colour will be projected above and an extra blue will come up below an image containing something as simple as a lone black line. In manufacturing LCD projectors can be adapted to remove these effects on the projected image, because each colour is directed on a separate LCD panels.

The one real benefit (excluding price) with choosing a DLP projector is its smaller overall size and weight. However, this is only relevant in regard to transporting the device and has to be traded off against the image advantages of LCD projectors. If overall picture quality is crucial to you, then the solution is easy. Go for an LCD projector! LCD projectors will constantly make bright, colourful images with fewer image imperfections. If you want to know more about LCD technology in more detail, check out this tremendous resource website: Explore 3LCD. If you have any other questions, go to Projector Central and send me an email.

Jonathan King is the sales and marketing manager for Projector Central, Australia’s leading online shop for projectors. Brisbane based, Projector Central has been servicing Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.