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The typical question asked when acquiring a new projector for the home, office, or classroom is: do I get an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two most common projector imaging technologies. With so many business brands and different models available, it can be challenging for the buyer to make a decision between these technologies. The simple fact of the matter is that LCD projectors give far better image quality and colour accuracy. The next paragraph explains why DLP projectors struggle with reproducing an equal level of image quality.

Imagine a set of blinds in your room on your bedroom window. With the twist of a rod you can turn the shutters open or closed, according to if you want to let light in or not. And this is exactly how an LCD projector functions. Each pixel operates like a unique shutter on a set of blinds to either send light through or to block it. DLP on the other hand is constructed of millions of microscopic mirrors or ‘pixel elements’ as 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 at which the projector turns on to when the image reaches your screen is extremely important for image quality, brightness and colour accuracy. LCD projectors direct white light from the lamp by separating 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 form the elements of the image by shining 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 directed onto your projected surface simultaneously. The way a DLP projector runs is totally different and even the produced image appears is not the same. With DLP, white light from the lamp is processed through a rotating colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of forming an image requires a sequence of red, blue and green light. The millions of micro mirrors as mentioned above reflect the coloured light on the pixels to construct the image elements. The elements of the image are displayed 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 single full image. With LCD projectors, all colours are available all the time to form the highest brightness and spectacular colour accuracy. In DLP, just one colour is available at a time, causing lower colour brightness and accuracy. Some manufacturers have included a white segment in the colour wheel to improve overall brightness, but this then lessens colour accuracy.

I hear in forums all the time that DLP has a higher contrast ratio and ergo must be better quality. For those who do not know, 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 producing. DLP projectors do provide high contrast specifications when compared to a majority of LCD projectors. At one glance, this seems to be a benefit, however, in real life, the true black level is determined by the ambient light in the room where the projector is utilised. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you plan to view has moving images, DLP projection technology can also have image marks, or ‘artifacts’. The most often seen artifact that a DLP projector shows with moving images is colour break up. Colour break up is inherent in DLP systems because moving images change up between the time red, blue and green colours are projected. LCD projectors do not have this disadvantage because all colours are projected with the others. DLP manufacturers have developed 3DLP solutions using 3 chips to solve the colour break up issue, but the price of these projectors make them impractical for the large part of businesses and consumers.

Another differentiation between LCD and DLP is how they compensate for the refractive qualities of light. Jump back to high school science, and they taught you how the different colours of light refract various amounts when passing through the same lens. The downside with DLP projectors is that they have the one same panel for the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light in different ways. Often with a DLP projector, an extra yellow colour will appear above and a superfluous blue will come through below an image containing something as simple as a lone black line. During manufacturing LCD projectors can be fixed to minimize these effects on the projected image, as each colour is projected on isolated LCD panels.

The sole true plus (excluding price) with taking a DLP projector is its smaller total size and weight. However, this is only relevant with regard to portability and needs to be traded off against the image superiority of LCD projectors. If resulting picture quality is crucial to you, then the solution is simple. Take an LCD projector! LCD projectors will constantly make bright, colourful images with fewer image imperfections. If you want to learn more about LCD technology in more detail, have a gander at this fabulous resource website: Explore 3LCD. If you have any other questions, go to Projector Central and send me an email.

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