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The most common question that is asked when purchasing a new projector for the home, office, or classroom is: would I purchase an LCD projector or a DLP projector? LCD, an acronym for ‘liquid crystal device’ and DLP, which stands for ‘digital light processing’ are the two most popular projector imaging technologies. With so many different brands and models available, it can be confusing for customers to choose between both technologies. It comes down to the fact that LCD projectors offer superior image quality and colour accuracy. The next paragraph will explain why DLP projectors struggle with bringing up the same level of image quality.

Imagine a set of blinds in your household covering your bedroom window. By a twist of a rod you can have the shutters open or closed, depending on if you want to let light in or not. And such is exactly how an LCD projector behaves. Each pixel operates like a single shutter on a set of blinds to either send light through or to block it. DLP on the other hand is created of millions of microscopic mirrors or ‘pixel elements’ as professionals 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 turns on to when the picture reaches your screen is extremely significant for 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 project the coloured light to 3 stand alone LCD panels. The 3 LCD panels create the elements of the image by processing each pixel on and off. The pixels are then projected in a glass prism to send the projector image. An important point to know about LCD projectors is that all three colours are directed onto your projected surface at once. The way a DLP projector runs is widely different and even how an image shows up is not the same. With DLP, white light from the lamp is sent through a spinning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of projecting an image forms a sequence of red, blue and green light. The millions of micro mirrors mentioned above reflect the coloured light on the pixels to create 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 total image. With LCD projectors, all colours are available all the time to deliver the highest brightness and fantastic colour accuracy. In DLP, only one colour is available at a time, and so resulting in lower colour brightness and accuracy. Some designers have placed a white segment into the colour wheel to improve brightness overall, but this goes and lessens colour accuracy.

I see in forums all the time that DLP gives a higher contrast ratio and thus must be superior. For those unaware, 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 able to produce. DLP projectors do possess high contrast specifications compared to the majority of LCD projectors. At a glance, this seems to be a benefit, however, in the real world, the true black level is determined by the ambient light in the room where the projector is utilised. Do not be fooled by contrast specifications on websites and in brochures.

When the content you are trying to view includes moving images, DLP projection technology also creates image errors, or ‘artifacts’. The most commonplace artifact that a DLP projector creates with moving images is colour break up. Colour break up is inherent in DLP systems because moving images change between the time red, blue and green colours are projected. LCD projectors do not have this problem because every colour is sent with the others. DLP builders have developed 3DLP solutions using 3 chips to resolve the colour break up problem, but the price of these projectors make them almost impossible for the large part of businesses and consumers.

Another difference 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 different colours of light refract different amounts when projected through the same lens. The disadvantage 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 obviously not the same and refract light at different levels. Often with a DLP projector, some yellow colour will be projected above and some extra blue will show below an image as simple as a straight black line. In building LCD projectors can be fixed to take away these effects on the projected image, as each colour is refracted on isolated LCD panels.

The one actual plus (excluding price) with picking a DLP projector is its overall smaller size and weight. However, this is only relevant with regard to mobility and has to be traded off against the image plusses of LCD projectors. If the outcome of the picture quality is important to you, then the decision is simple. Go with an LCD projector! LCD projectors will consistently produce bright, colourful images with fewer image errors. If you need to learn more about LCD technology in more detail, have a gander at this fabulous 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 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.