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The most typical question heard when acquiring a new projector for the home, office, or classroom is: do I buy an LCD projector or a DLP projector? LCD, standing for ‘liquid crystal device’ and DLP, standing for ‘digital light processing’ are the two top projector imaging technologies. With so many different brands and different types available, it can be overwhelming for the buyer to pick between both technologies. The simple fact of the matter is that LCD projectors offer superior image quality and colour accuracy. The article below will tell you why DLP projectors struggle with bringing up the same grade of image quality.

Think of a set of blinds in your home on your bedroom window. By a twist of a rod you can make the shutters open or closed, depending on whether you want to let light in or not. Such is exactly how an LCD projector functions. Each pixel functions like a single shutter on a set of blinds to either shine light through or to block it. DLP on the other hand is constructed of millions of microscopic mirrors or ‘pixel elements’ as 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 when the projector is switched on to when the picture reaches your screen is ultimately important for image quality, brightness and colour accuracy. LCD projectors project white light from the lamp by separating it into red, blue and green components, by three mirrors which transfer the coloured light to 3 separate LCD panels. The 3 LCD panels make the elements of the image by switching each pixel on and off. The pixels are then meshed in a glass prism to create the projector image. A significant point to understad about LCD projectors is that all three colours are directed onto your wall at once. The way a DLP projector works is vastly different and even how an image shows up 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 way of forming an image requires a sequence of red, blue and green light. The millions of micro mirrors described above reflect the coloured light on the pixels to produce the image elements. The elements of the image are sent 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. In LCD projectors, all colours are available all the time to create top brightness and great colour accuracy. In DLP, only one colour is available at once, and so causing lower colour brightness and accuracy. Some developers have included a white segment for the colour wheel to improve general brightness, but this also degrades colour accuracy.

I hear in forums all the time that DLP gives a higher contrast ratio and ergo must be superior. For those who are unsure, 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 capable of producing. DLP projectors do have high contrast specifications as compared to a majority of LCD projectors. At one glance, this seems to be a plus, however, in real life, the true black level is determined by the ambient light in the room in which the projector is in use. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you wish to see has moving images, DLP projection technology also creates image imperfections, or ‘artifacts’. The most commonplace 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 up between the time red, blue and green colours are projected. LCD projectors do not have this characteristic because all the colours are projected simultaneously. DLP designers have created 3DLP solutions using 3 chips to answer the colour break up issue, but the price tag of these projectors make them hardly practical for the majority of businesses and consumers.

Another point of difference between LCD and DLP is how they make up for the refractive qualities of light. Think back to high school science, and recall how different colours of light refract different amounts when projected through the same lens. The downfall with DLP projectors is that they utilise the one same panel for the same lens to project Red, Blue and Green. All 3 colours are not the same and refract light in different ways. Often with a DLP projector, a spill of yellow colour will come through above and some blue will come up below something as simple as a single black line. While being built LCD projectors can be fixed to reduce these effects on the projected image, as each colour is directed on its own LCD panels.

The only real benefit (excluding price) with buying a DLP projector is its overall smaller size and weight. However, this is only relevant with regard to mobility and cannot be traded off against the image advantages of LCD projectors. If resulting picture quality is important to you, then the decision is easy. Take an LCD projector! LCD projectors will constantly make bright, colourful images with fewer image blips. If you wish to find out more about LCD technology in more detail, have a gander at this tremendous resource website: Explore 3LCD. If you have any further questions, jump onto Projector Central and send me an email.

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