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The common question that is asked when looking for a new projector for the home, office, or classroom is: do I buy an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, standing for ‘digital light processing’ are the two top projector imaging technologies. With so many company brands and different models available, it can be challenging for consumers to decide between both technologies. Ultimately LCD projectors offer better image quality and colour accuracy. The article below explains why DLP projectors struggle with reproducing a comparable rate of image quality.

Imagine a set of blinds in your house on your bedroom window. By twisting a rod you can make the shutters open or closed, according to if you want to let light in or not. This is exactly how an LCD projector behaves. Each pixel functions like its own shutter on a set of blinds to either allow light through or to block it. DLP on the other hand is made up 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 at which the projector switches on to when the content reaches your screen is absolutely significant for image quality, brightness and colour accuracy. LCD projectors process white light from the lamp by separating it into red, blue and green components, by three mirrors which direct the coloured light to 3 different LCD panels. The 3 LCD panels make the elements of the image by shining each pixel on and off. The pixels are then meshed in a glass prism to create the projector image. A significant point to remember about LCD projectors is that all three colours are projected onto your projector screen at the same time. The way a DLP projector operates is totally different and even the produced image comes out is not the same. With DLP, white light from the lamp is processed through a spinning 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 described above reflect the coloured light on the pixels to form the image elements. The elements of the image are cast in sequence on the screen, one colour at a time. The viewer’s eyes will then pull together each coloured element of the image into a single full image. Using 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 once, resulting in lower colour brightness and accuracy. Some DLP developers have added a white segment in the colour wheel to improve general brightness, but this then degrades colour accuracy.

I find in forums all the time that DLP provides a higher contrast ratio and therefore must be better. 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 projector is able to produce. DLP projectors do offer high contrast specifications when compared to the majority of LCD projectors. At one glance, this can seem to be a benefit, however, in truth, the true black level is determined by the ambient light in the room where the projector is utilised. Do not be tricked by contrast specifications on websites and in brochures.

When the content you plan to project has moving images, DLP projection technology also creates image marks, or ‘artifacts’. The most commonplace artifact that a DLP projector displays 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 pulled up. LCD projectors do not have this characteristic because the colours are delivered at once. DLP builders have formed 3DLP solutions using 3 chips to fix the colour break up artifacts, but the price tag of these projectors make them hardly practical for the majority of businesses and consumers.

Another difference between LCD and DLP is how they compensate for the refractive qualities of light. Jump back to high school science, and remember when they taught you how different colours of light refract differing amounts when shone through the same lens. The downfall with DLP projectors is that they utilise the one same panel and the same lens to project Red, Blue and Green. All 3 colours are not the same and refract light differently. Generally with a DLP projector, some extra yellow colour will come up above and a spill of blue will appear below something as simple as a straight black line. During manufacturing LCD projectors can be set to reduce these effects on the projected image, because each colour is refracted on isolated LCD panels.

The one real benefit (excluding price) with buying a DLP projector is its smaller total size and weight. However, this is only relevant in regard to portability and cannot be traded off against the image superiority of LCD projectors. If resulting picture quality is important to you, then the solution is simple. Go for an LCD projector! LCD projectors will consistently produce bright, colourful images with fewer image blips. If you need to learn more about LCD technology in more detail, have a look at this fabulous resource website: Explore 3LCD. If you have any further questions, get onto Projector Central and send me an email.

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