The typical question heard when purchasing a new projector for the home, office, or classroom is: would I buy an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, standing for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many different brands and models available, it can be difficult for clients to decide between both technologies. It comes down to the fact that LCD projectors offer better image quality and colour accuracy. The next paragraph will explain why DLP projectors struggle with reproducing a comparable rate of image quality.

It’s like a set of blinds in your room on your bedroom window. By pulling a rod you can make the shutters open or closed, according to if you want to let light in or not. Such is exactly how an LCD projector behaves. Each pixel functions like a single 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 time the projector is turned on to when the content reaches your screen is absolutely significant to image quality, brightness and colour accuracy. LCD projectors shine white light from the lamp by dividing it into red, blue and green components, by three mirrors which send the coloured light to 3 stand alone LCD panels. The 3 LCD panels make the elements of the image by switching each pixel on and off. The pixels are then projected in a glass prism to create the projector image. A point to understad about LCD projectors is that all three colours are directed onto your projected surface all at the same time. The way a DLP projector runs is very different and even the way an image shows up is not the same. With DLP, white light from the lamp is projected through a rotating colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This way of forming an image casts a sequence of red, blue and green light. The millions of micro mirrors described above reflect the coloured light on the pixels to produce 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 the total image. Using 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, 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 lessens colour accuracy.

I see in forums all the time that DLP gives a higher contrast ratio and as such must be better quality. For those who are 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 technology is able to produce. DLP projectors do possess high contrast specifications when compared to the majority of LCD projectors. At one glance, this can seem to be a benefit, however, in truth, the true black level is determined by the ambient light in the room while the projector is used. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you are trying to see has moving images, DLP projection technology also creates image errors, or ‘artifacts’. The most often seen artifact that a DLP projector displays with moving images is colour break up. Colour break up is incontrovertible in DLP systems because moving images keep changing between the time red, blue and green colours are projected. LCD projectors do not have this disadvantage because all the colours are projected with the others. DLP manufacturers have developed 3DLP solutions using 3 chips to resolve the colour break up artifacts, but the price tag of these projectors make them hardly practical for most businesses and consumers.

Another variance between LCD and DLP is how they compensate for the refractive qualities of light. Take yourself back to high school science, and recall how different colours of light refract varied amounts when shone through the same lens. The downside 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 not the same and refract light at different levels. Most of the time with a DLP projector, some yellow colour will be projected above and a superfluous blue will come up below an image as simple as a lone black line. In manufacturing LCD projectors can be set to minimize these effects on the projected image, as each colour is projected on a separate LCD panels.

The one veritable plus (excluding price) with deciding on a DLP projector is its overall smaller size and weight. However, this is only relevant for transporting the device and cannot be traded off against the image plusses of LCD projectors. If the outcome of the picture quality is crucial to you, then the decision is simple. Take an LCD projector! LCD projectors will always create bright, colourful images with fewer image mistakes. If you wish to learn more about LCD technology in more detail, have a gander at this spectacular 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 of Projector Central, Australia’s number one online provider for projectors. Brisbane based, Projector Central has served Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.