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The common question heard when buying a new projector for the home, office, or classroom is: do I purchase an LCD projector or a DLP projector? LCD, an acronym for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many business brands and different types available, it can be difficult for clients to make a decision between the two technologies. The simple fact of the matter is that LCD projectors have better image quality and colour accuracy. The next part of this article tells you why DLP projectors struggle with reproducing the same rate of image quality.

Visualise a set of blinds in your room over your bedroom window. By pulling on a rod you can turn the shutters open or closed, depending on whether you want to let light in or not. And such is exactly how an LCD projector works. Each pixel works like a unique shutter on a set of blinds to either allow light through or to block it. DLP on the other hand is formed 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 switched on to when the image reaches your screen is vitally important to image quality, brightness and colour accuracy. LCD projectors direct white light from the lamp by cutting it into red, blue and green components, by three mirrors which direct the coloured light to 3 different LCD panels. The 3 LCD panels cast the elements of the image by shining each pixel on and off. The pixels are then combined in a glass prism to create the projector image. An important point to remember about LCD projectors is that all three colours are projected onto your screen all at the same time. The way a DLP projector works is totally different and even the final product of how an 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 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 produce the image elements. The elements of the image are displayed in sequence on the screen, one colour at a time. The viewer’s vision will then combine each coloured element of the image into a single total image. In LCD projectors, all colours are available all the time to create the highest brightness and great colour accuracy. In DLP, only one colour is available at once, and so resulting in lower colour brightness and accuracy. Some developers have included a white segment in the colour wheel to improve brightness generally, but this further degrades colour accuracy.

I read in forums all the time that DLP offers 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 technology is able to produce. DLP projectors do have high contrast specifications compared to the majority of LCD projectors. At first glance, this seems to be a plus, however, in the real world, the true black level is determined by the ambient light in the room while the projector is in use. Do not be duped by contrast specifications on websites and in brochures.

When the content you wish to see requires moving images, DLP projection technology also has image marks, or ‘artifacts’. The most common artifact that a DLP projector displays with moving images is colour break up. Colour break up is unavoidable in DLP systems because moving images change between the time red, blue and green colours are displayed. LCD projectors do not have this downside because all colours are projected at once. DLP builders have formed 3DLP solutions using 3 chips to solve the colour break up problem, but the price of these projectors make them almost impossible for many businesses and consumers.

Another variance 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 various colours of light refract varied amounts when directed through the same lens. The downfall with DLP projectors is that they utilise the one same panel for 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 appear above and a superfluous blue will be projected below an image as simple as a lone black line. While being built LCD projectors can be set to take away these effects on the projected image, because each colour is refracted on its own LCD panels.

The sole real benefit (excluding price) with picking a DLP projector is its smaller total size and weight. However, this is only relevant to mobility and cannot be traded off against the image plusses of LCD projectors. If the outcome of the picture quality is vital to you, then the decision is simple. Choose 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 persisting 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 shop 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.