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The common question customers ask when buying a new projector for the home, office, or classroom is: should I get 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 brands and models available, it can be overwhelming for consumers to pick between those technologies. Ultimately LCD projectors provide better image quality and colour accuracy. The article below explains why DLP projectors struggle with projecting a comparable grade of image quality.

It’s like a set of blinds in your home over your bedroom window. With the twist of 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 works like a single shutter on a set of blinds to either send light through or to block it. DLP on the other hand is made up 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 at which the projector is turned on to when the picture reaches your screen is vitally significant for image quality, brightness and colour accuracy. LCD projectors project white light from the lamp by cutting it into red, blue and green components, by three mirrors which send the coloured light to 3 separate LCD panels. The 3 LCD panels cast the elements of the image by switching each pixel on and off. The pixels are then meshed in a glass prism to send the projector image. A point to understad about LCD projectors is that all three colours are projected onto your screen simultaneously. The way a DLP projector functions is widely different and even the produced image appears is not the same. With DLP, white light from the lamp is sent through a rotating colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This approach to forming an image casts a sequence of red, blue and green light. The millions of micro mirrors mentioned 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 vision will then combine each coloured element of the image into the total image. Using LCD projectors, all colours are available all the time to deliver high brightness and fantastic colour accuracy. In DLP, only one colour is available at any given time, resulting in lower colour brightness and accuracy. Some DLP developers have put a white segment for the colour wheel to improve general brightness, but this also detracts from colour accuracy.

I read in forums all the time that DLP gives a higher contrast ratio and as such 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 able to produce. DLP projectors do have high contrast specifications when compared to many LCD projectors. Initially, this seems to be an advantage, however, in truth, the true black level is determined by the ambient light in the room where the projector is being used. Do not be fooled by contrast specifications on websites and in brochures.

When the content you wish to project has moving images, DLP projection technology can also have image marks, or ‘artifacts’. The most typical 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 position between the time red, blue and green colours are shone. LCD projectors do not have this problem because all colours are processed with the others. DLP designers have created 3DLP solutions using 3 chips to fix the colour break up artifacts, but the price tag of these projectors make them not practical for many businesses and consumers.

Another variance between LCD and DLP is how they make up for the refractive qualities of light. Jump back to high school science, and they taught you how different colours of light refract various amounts when projected through the same lens. The downside 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, a spill of yellow colour will show above and a superfluous blue will show below an image containing something as simple as a single black line. In manufacturing LCD projectors can be adapted to minimize these effects on the projected image, as each colour is refracted on isolated LCD panels.

The one veritable plus (excluding price) with taking a DLP projector is its smaller overall size and weight. However, this is only relevant to portability and has to be traded off against the image benefits of LCD projectors. If the result of the picture quality is crucial to you, then the choice is no-brainer. Go for an LCD projector! LCD projectors will constantly produce bright, colourful images with fewer image imperfections. If you desire to ask more about LCD technology in more detail, see this tremendous resource website: Explore 3LCD. If you have any further questions, go to 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 been servicing Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.