The most typical question that is 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, an acronym 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 clients to pick between these technologies. The simple fact of the matter is that LCD projectors offer superior image quality and colour accuracy. The next paragraph explains why DLP projectors struggle with bringing up an equal level of image quality.

It’s like a set of blinds in your household on your bedroom window. By a twist of a rod you can turn the shutters open or closed, according to if you want to let light in or not. That is exactly how an LCD projector operates. Each pixel operates like a unique shutter on a set of blinds to either allow light through or to block it. DLP on the other hand is created of millions of microscopic mirrors or ‘pixel elements’ as the professionals like to call them. Each pixel element works to either reflect light or block it.

How the light source is processed from the point when the projector turns on to when the image reaches your screen is vitally important for image quality, brightness and colour accuracy. LCD projectors project white light from the lamp by separating it into red, blue and green components, by three mirrors which direct the coloured light to 3 individual LCD panels. The 3 LCD panels make the elements of the image by processing each pixel on and off. The pixels are then simultaneously processed in a glass prism to create the projector image. An important point to realise about LCD projectors is that all three colours are directed onto your projected surface all at once. The way a DLP projector functions is widely different and even the final product of how an image comes out is not the same. With DLP, white light from the lamp is projected through a turning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This way of projecting an image requires 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 projected in sequence on the screen, one colour at a time. The viewer’s eye will then put together each coloured element of the image into the whole image. From LCD projectors, all colours are available all the time to offer high brightness and superb colour accuracy. In DLP, only one colour is available at once, and so resulting in lower colour brightness and accuracy. Some DLP designers have added a white segment for the colour wheel to improve overall brightness, but this also detracts from colour accuracy.

I see in forums all the time that DLP offers a higher contrast ratio and therefore must be superior quality. 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 machine is capable of. DLP projectors do have high contrast specifications as compared to the majority of LCD projectors. At first glance, this must be a benefit, however, in truth, the true black level is determined by the ambient light in the room when the projector is being used. Do not be tricked by contrast specifications on websites and in brochures.

When the content you wish to view requires moving images, DLP projection technology also creates image marks, or ‘artifacts’. The most typical artifact that a DLP projector displays 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 pulled up. LCD projectors do not have this downside because all colours are projected with the others. DLP developers have formed 3DLP solutions using 3 chips to answer the colour break up error, but the cost of these projectors make them almost impossible for the majority of businesses and consumers.

Another differentiation between LCD and DLP is how they compensate for the refractive qualities of light. Remember back to high school science, and they taught you how various colours of light refract varied amounts when directed through the same lens. The disadvantage with DLP projectors is that they take the one same panel with the same lens to project Red, Blue and Green. All 3 colours are obviously not the same and refract light differently. Generally with a DLP projector, some extra yellow colour will be projected above and a superfluous blue will show below an image as simple as a straight black line. In manufacturing LCD projectors can be fixed to reduce these effects on the projected image, as each colour is processed on isolated LCD panels.

The isolated actual buy point (excluding price) with going with a DLP projector is its smaller overall size and weight. However, this is only relevant to portability and needs to be traded off against the image advantages of LCD projectors. If overall picture quality is important to you, then the solution is no-brainer. Go with an LCD projector! LCD projectors will always create bright, colourful images with fewer image mistakes. If you need to find out more about LCD technology in more detail, check out this spectacular resource website: Explore 3LCD. If you have any additional questions, visit 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. Brisbane-based, Projector Central has been servicing Australia for 15 years. For data projectors in the Gold Coast and Interactive Whiteboards, contact Projector Central today.

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