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The typical question customers ask when buying a new projector for the home, office, or classroom is: will I buy 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 brands and different types available, it can be difficult for the buyer to pick between those technologies. The simple fact of the matter is that LCD projectors give far superior image quality and colour accuracy. The next paragraph will tell you why DLP projectors struggle with projecting the same rate of image quality.

Visualise a set of blinds in your home for your bedroom window. With the twist of a rod you can make the shutters open or closed, depending on whether you want to let light in or not. That is exactly how an LCD projector behaves. Each pixel works like a single shutter on a set of blinds to either pass light through or to block it. DLP on the other hand is created of millions of microscopic mirrors or ‘pixel elements’ as the experts like to call them. Each pixel element operates to either reflect light or block it.

How the light source is processed from the point at which the projector is turned on to when the content reaches your screen is ultimately significant in regard to image quality, brightness and colour accuracy. LCD projectors direct white light from the lamp by dividing it into red, blue and green components, by three mirrors which transfer the coloured light to 3 separate LCD panels. The 3 LCD panels form the elements of the image by switching each pixel on and off. The pixels are then combined in a glass prism to form the projector image. A point to understad about LCD projectors is that all three colours are sent onto your projector screen all at once. The way a DLP projector operates is widely different and even the final product of how an image comes out is not the same. With DLP, white light from the lamp is projected through a spinning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This way 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 construct the image elements. The elements of the image are projected in sequence on the screen, one colour at a time. The viewer’s eyes will then combine each coloured element of the image into the single full image. Using LCD projectors, all colours are available all the time to form the best brightness and great colour accuracy. In DLP, only one colour is available at a time, causing lower colour brightness and accuracy. Some DLP designers have included a white segment into the colour wheel to improve general brightness, but this then damages colour accuracy.

I read in forums all the time that DLP offers a higher contrast ratio and as such must be better quality. For those uncertain, 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 machine is capable of. DLP projectors do have high contrast specifications compared to a majority of LCD projectors. At first glance, this appears to be an advantage, however, in truth, the true black level is determined by the ambient light in the room when the projector is in use. Do not be tricked by contrast specifications on websites and in brochures.

When the content you want to project requires moving images, DLP projection technology can also create image marks, or ‘artifacts’. The most often seen artifact that a DLP projector forms with moving images is colour break up. Colour break up is unavoidable in DLP systems because moving images change position between the time red, blue and green colours are pulled up. LCD projectors do not have this downside because the colours are processed at the same time. DLP builders have developed 3DLP solutions using 3 chips to answer the colour break up artifacts, but the expense of these projectors make them impractical for most businesses and consumers.

Another variance between LCD and DLP is how they balance for the refractive qualities of light. Take yourself back to high school science, and they taught you how the various colours of light refract different amounts when shone through the same lens. The problem with DLP projectors is that they have the one same panel and the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light at different levels. Usually with a DLP projector, some yellow colour will appear above and some extra blue will come up below an image containing something as simple as a straight black line. While being built LCD projectors can be adapted to remove these effects on the projected image, as each colour is refracted on isolated LCD panels.

The isolated real plus (excluding price) with deciding on a DLP projector is its smaller total size and weight. However, this is only relevant in regard to portability and must be traded off against the image plusses of LCD projectors. If resulting picture quality is important to you, then the answer is simple. Choose an LCD projector! LCD projectors will definitely create bright, colourful images with fewer image blips. If you want to learn more about LCD technology in more detail, check out this spectacular resource website: Explore 3LCD. If you have any more questions, go to Projector Central and send me an email.

Jonathan King is the sales and marketing manager with Projector Central, Australia’s number one online provider for projectors. Brisbane based, Projector Central has been serving Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.