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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 take an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, standing for ‘digital light processing’ are the two most common projector imaging technologies. With so many brands and different models available, it can be difficult for consumers to pick between both technologies. It comes down to the fact that LCD projectors offer better image quality and colour accuracy. The next part of this article will tell you why DLP projectors struggle with projecting the same level of image quality.

Imagine a set of blinds in your home over your bedroom window. With the twist of a rod you can have the shutters open or closed, depending on if you want to let light in or not. Such is exactly how an LCD projector works. Each pixel works like an individual 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 pros 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 content reaches your screen is vitally significant with regard to image quality, brightness and colour accuracy. LCD projectors shine white light from the lamp by separating 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 make the elements of the image by processing each pixel on and off. The pixels are then combined in a glass prism to deliver the projector image. An important point to remember about LCD projectors is that all three colours are projected onto your screen at the same time. The way a DLP projector functions is vastly different and even how an image comes out is not the same. With DLP, white light from the lamp is directed through a turning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This way of creating an image requires 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 draw each coloured element of the image into a complete image. Using LCD projectors, all colours are available all the time to offer high brightness and spectacular colour accuracy. In DLP, only one colour is available at once, resulting in lower colour brightness and accuracy. Some DLP manufacturers have included a white segment for the colour wheel to improve brightness generally, but this further degrades colour accuracy.

I see in forums all the time that DLP has a higher contrast ratio and therefore must be better. For those who are uncertain, 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 able to produce. DLP projectors do possess high contrast specifications when compared to the majority of LCD projectors. At first glance, this seems to be an advantage, however, in the real world, the true black level is determined by the ambient light in the room while the projector is utilised. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you are trying to view needs moving images, DLP projection technology also has image marks, or ‘artifacts’. The most typical artifact that a DLP projector forms with moving images is colour break up. Colour break up is incontrovertible in DLP systems because moving images change up between the time red, blue and green colours are displayed. LCD projectors do not have this problem because the colours are processed simultaneously. DLP manufacturers have created 3DLP solutions using 3 chips to solve the colour break up error, but the price tag of these projectors make them hardly practical for many businesses and consumers.

Another point of difference between LCD and DLP is how they make up for the refractive qualities of light. Think back to high school science, and they taught you how various colours of light refract differing amounts when directed through the same lens. The problem with DLP projectors is that they take 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 in a different way. Generally with a DLP projector, a spill of yellow colour will show above and an extra blue will be projected below an image of something as simple as a lone black line. During manufacturing LCD projectors can be adapted to minimize these effects on the projected image, as each colour is projected on isolated LCD panels.

The only actual advantage (excluding price) with taking a DLP projector is its smaller size and weight. However, this is only relevant for portability and must be traded off against the image superiority of LCD projectors. If the result of the picture quality is vital to you, then the choice is easy. Take an LCD projector! LCD projectors will constantly show bright, colourful images with fewer image blips. If you want to find out more about LCD technology in more detail, see this fabulous resource website: Explore 3LCD. If you have any other questions, get onto Projector Central and send me an email.

Jonathan King is the sales and marketing manager with Projector Central, Australia’s leading online provider for projectors. Brisbane-based, Projector Central has been serving Australia for 15 years. For data projectors in the Gold Coast and Interactive Whiteboards, contact Projector Central today.