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The most typical question asked when looking for a new projector for the home, office, or classroom is: should I purchase 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 brands and different types available, it can be difficult for consumers to make a choice between these technologies. Ultimately LCD projectors offer better image quality and colour accuracy. The article below will tell you why DLP projectors struggle with bringing up a similar level of image quality.

It’s like a set of blinds in your home covering 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 behaves. Each pixel operates like its own shutter on a set of blinds to either shine 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 operates to either reflect light or block it.

How the light source is processed from the time the projector is turned on to when the picture reaches your screen is ultimately important to image quality, brightness and colour accuracy. LCD projectors process white light from the lamp by splitting it into red, blue and green components, by three mirrors which transfer the coloured light to 3 separate LCD panels. The 3 LCD panels cast the elements of the image by processing each pixel on and off. The pixels are then combined in a glass prism to send the projector image. Something important to realise about LCD projectors is that all three colours are delivered onto your projected surface all at once. The way a DLP projector runs is very different and even how an image comes out 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 mentioned above reflect the coloured light on the pixels to create the image elements. The elements of the image are sent 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 a complete image. From LCD projectors, all colours are available all the time to form top brightness and superb colour accuracy. In DLP, just one colour is available at once, causing lower colour brightness and accuracy. Some DLP developers have put a white segment in the colour wheel to improve general brightness, but this also lessens colour accuracy.

I read in forums all the time that DLP has a higher contrast ratio and ergo must be better. 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 offer high contrast specifications as compared to the majority of LCD projectors. At first glance, this must be a benefit, however, in the real world, the true black level is determined by the ambient light in the room while the projector is being utilised. Do not be fooled by contrast specifications on websites and in brochures.

When the content you are trying to see requires moving images, DLP projection technology can also have image imperfections, or ‘artifacts’. The most typical artifact that a DLP projector shows 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 problem because the colours are projected simultaneously. DLP developers have developed 3DLP solutions using 3 chips to resolve the colour break up artifacts, but the price of these projectors make them hardly practical for most businesses and consumers.

Another point of difference between LCD and DLP is how they balance for the refractive qualities of light. Jump back to high school science, and they taught you how various colours of light refract various amounts when directed through the same lens. The downside with DLP projectors is that they use the one same panel for the same lens to project Red, Blue and Green. All 3 colours are different and refract light differently. Often with a DLP projector, a superfluous yellow colour will come up above and some blue will be projected below an image containing something as simple as a lone black line. While being built LCD projectors can be adapted to minimize these effects on the projected image, as each colour is directed on separate LCD panels.

The only true benefit (excluding price) with deciding on a DLP projector is its smaller overall size and weight. However, this is only relevant with regard to transport and has to be traded off against the image benefits of LCD projectors. If the result of the picture quality is important to you, then the solution is easy. Choose an LCD projector! LCD projectors will definitely show bright, colourful images with fewer image mistakes. If you want to find out more about LCD technology in more detail, see this tremendous resource website: Explore 3LCD. If you have any persisting questions, jump onto Projector Central and send me an email.

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