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The common question asked when looking for a new projector for the home, office, or classroom is: should I buy an LCD projector or a DLP projector? LCD, standing for ‘liquid crystal device’ and DLP, which stands for ‘digital light processing’ are the two most popular projector imaging technologies. With so many brands and models available, it can be difficult for customers to make a choice between the two technologies. It comes down to the fact that LCD projectors give far superior image quality and colour accuracy. The next part of this article will tell you why DLP projectors struggle with projecting an equal standard of image quality.

Visualise a set of blinds in your room over your bedroom window. By pulling on a rod you can turn the shutters open or closed, depending on if you want to let light in or not. Such is exactly how an LCD projector functions. Each pixel operates like its own shutter on a set of blinds to either shine light through or to block it. DLP on the other hand is created of millions of microscopic mirrors or ‘pixel elements’ as pros 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 turned on to when the image reaches your screen is ultimately important with 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 transfer 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 simultaneously processed in a glass prism to create the projector image. An important point to remember about LCD projectors is that all three colours are sent onto your screen all at the same time. The way a DLP projector runs is totally different and even the final product of how an image appears is not the same. With DLP, white light from the lamp is directed through a rotating colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This approach to creating an image creates a sequence of red, blue and green light. The millions of micro mirrors described above reflect the coloured light on the pixels to construct 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 combine each coloured element of the image into a whole image. With LCD projectors, all colours are available all the time to create the best brightness and superb colour accuracy. In DLP, just one colour is available at any given time, resulting in lower colour brightness and accuracy. Some manufacturers have included a white segment for the colour wheel to improve all over brightness, but this then damages colour accuracy.

I find in forums all the time that DLP provides a higher contrast ratio and ergo must be better 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. DLP projectors do have high contrast specifications when compared to a majority of LCD projectors. Initially, this can seem to be an advantage, however, in reality, the true black level is determined by the ambient light in the room in which the projector is being used. Do not be duped by contrast specifications on websites and in brochures.

When the content you plan to view has moving images, DLP projection technology also has image marks, or ‘artifacts’. The most commonplace artifact that a DLP projector shows with moving images is colour break up. Colour break up is incontrovertible in DLP systems because moving images keep changing between the time red, blue and green colours are displayed. LCD projectors do not have this disadvantage because all colours are projected simultaneously. DLP builders have created 3DLP solutions using 3 chips to resolve the colour break up problem, but the cost of these projectors make them not practical for the large part of businesses and consumers.

Another point of difference between LCD and DLP is how they match the balance for the refractive qualities of light. Jump back to high school science, and recall how various colours of light refract different amounts when shone through the same lens. The disadvantage with DLP projectors is that they take the one same panel for the same lens to project Red, Blue and Green. All 3 colours are different and refract light in a different way. Most of the time with a DLP projector, some yellow colour will come through above and a spill of blue will come through below an image containing something as simple as a lone black line. While being built LCD projectors can be set to minimize these effects on the projected image, as each colour is refracted on a separate LCD panels.

The sole real plus (excluding price) with picking a DLP projector is its smaller overall size and weight. However, this is only relevant to transporting the device and must be traded off against the image superiority of LCD projectors. If resulting picture quality is important to you, then the answer is a no-brainer. Take an LCD projector! LCD projectors will definitely make bright, colourful images with fewer image blips. If you wish to find out more about LCD technology in more detail, check out this fabulous 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 number one online provider for projectors. Brisbane-based, Projector Central has serviced Australia for 15 years. For data projectors in the Gold Coast and Interactive Whiteboards, contact Projector Central today.