The most typical question heard when buying a new projector for the home, office, or classroom is: should I take 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 models available, it can be difficult for customers to make a decision between the two technologies. It comes down to the fact that LCD projectors have far superior image quality and colour accuracy. The next paragraph tells you why DLP projectors struggle with reproducing a similar grade of image quality.

Think of a set of blinds in your room covering your bedroom window. By pulling on 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 operates. Each pixel functions like a unique shutter on a set of blinds to either allow light through or to block it. DLP on the other hand is formed of millions of microscopic mirrors or ‘pixel elements’ as pros like to call them. Each pixel element functions to either reflect light or block it.

How the light source is processed from the point when the projector switches on to when the content reaches your screen is vitally significant in regard to image quality, brightness and colour accuracy. LCD projectors project white light from the lamp by dividing it into red, blue and green components, by three mirrors which project the coloured light to 3 separate LCD panels. The 3 LCD panels create the elements of the image by switching each pixel on and off. The pixels are then meshed in a glass prism to form the projector image. Something important to understad about LCD projectors is that all three colours are delivered 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 spinning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This approach to forming an image requires a sequence of red, blue and green light. The millions of micro mirrors as mentioned above reflect the coloured light on the pixels to produce the image elements. The elements of the image are cast 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 single full image. In LCD projectors, all colours are available all the time to form the best brightness and great colour accuracy. In DLP, just one colour is available at once, and so causing lower colour brightness and accuracy. Some DLP designers have added a white segment into the colour wheel to improve brightness generally, but this goes and damages colour accuracy.

I find in forums all the time that DLP has a higher contrast ratio and as such must be superior quality. For those 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 system is capable of producing. DLP projectors do offer high contrast specifications when compared to a majority of LCD projectors. At a glance, this appears to be a benefit, however, in real life, the true black level is determined by the ambient light in the room where the projector is being used. Do not be tricked by contrast specifications on websites and in brochures.

When the content you are trying to view needs moving images, DLP projection technology also creates image errors, or ‘artifacts’. The most common artifact that a DLP projector forms with moving images is colour break up. Colour break up is unavoidable in DLP systems because moving images keep changing between the time red, blue and green colours are displayed. LCD projectors do not have this characteristic because every colour is delivered at the same time. DLP manufacturers have come up with 3DLP solutions using 3 chips to solve the colour break up issue, but the price of these projectors make them impractical for the majority of businesses and consumers.

Another point of difference 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 directed through the same lens. The downfall with DLP projectors is that they utilise the one same panel with the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light differently. Often with a DLP projector, a spill of yellow colour will show above and some extra blue will appear below something as simple as a single black line. While being built LCD projectors can be adjusted to minimize these effects on the projected image, because each colour is directed on separate LCD panels.

The isolated true buy point (excluding price) with buying a DLP projector is its smaller size and weight. However, this is only relevant with regard to mobility and has to be traded off against the image superiority of LCD projectors. If the result of the picture quality is important to you, then the solution is no-brainer. Go for an LCD projector! LCD projectors will always make bright, colourful images with fewer image imperfections. If you need to find out more about LCD technology in more detail, see this fabulous resource website: Explore 3LCD. If you have any additional questions, go to Projector Central and send me an email.

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