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The most typical question customers ask when buying a new projector for the home, office, or classroom is: will I get an LCD projector or a DLP projector? LCD, an acronym for ‘liquid crystal device’ and DLP, an acronym for ‘digital light processing’ are the two top projector imaging technologies. With so many business brands and different models available, it can be overwhelming for clients to make a decision between both technologies. It comes down to the fact that LCD projectors have far better image quality and colour accuracy. The next part of this article explains why DLP projectors struggle with reproducing a comparable level of image quality.

It’s like a set of blinds in your room over your bedroom window. By pulling on a rod you can have the shutters open or closed, according to if you want to let light in or not. This is exactly how an LCD projector operates. Each pixel functions like its own shutter on a set of blinds to either shine light through or to block it. DLP on the other hand is made up 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 when the projector turns on to when the image reaches your screen is ultimately important for 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 project the coloured light to 3 different 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 create the projector image. Something to know about LCD projectors is that all three colours are sent onto your projected surface simultaneously. The way a DLP projector functions is vastly different and even the produced image looks is not the same. With DLP, white light from the lamp is processed through a turning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This approach to projecting 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 produce 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 combine each coloured element of the image into the whole image. With LCD projectors, all colours are available all the time to offer top brightness and great colour accuracy. In DLP, only one colour is available at any given time, causing lower colour brightness and accuracy. Some DLP designers have added a white segment into the colour wheel to improve brightness overall, but this further lessens colour accuracy.

I see in forums all the time that DLP has a higher contrast ratio and ergo must be better quality. For those who don’t 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 projector is capable of producing. DLP projectors do have high contrast specifications in comparison to a majority of LCD projectors. At a glance, this must be an advantage, however, in real life, the true black level is determined by the ambient light in the room when the projector is utilised. Do not be fooled by contrast specifications on websites and in brochures.

When the content you wish to see includes moving images, DLP projection technology also creates image errors, or ‘artifacts’. The most commonplace artifact that a DLP projector forms with moving images is colour break up. Colour break up is unavoidable in DLP systems because moving images change position between the time red, blue and green colours are pulled up. LCD projectors do not have this characteristic because all colours are delivered at once. DLP developers 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 differentiation between LCD and DLP is how they compensate for the refractive qualities of light. Think back to high school science, and remember when they taught you how various colours of light refract differing amounts when shone through the same lens. The downside with DLP projectors is that they take the one same panel for the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light differently. Most of the time with a DLP projector, some yellow colour will appear above and a superfluous blue will appear below an image containing something as simple as a straight black line. While being built LCD projectors can be adapted to remove these effects on the projected image, because each colour is processed on separate LCD panels.

The one real advantage (excluding price) with taking a DLP projector is its smaller size and weight. However, this is only relevant in regard to transport and must be traded off against the image advantages of LCD projectors. If overall picture quality is important to you, then the answer is a no-brainer. Go with an LCD projector! LCD projectors will definitely make bright, colourful images with fewer image blips. If you need to learn more about LCD technology in more detail, have a gander at this fantastic resource website: Explore 3LCD. If you have any further questions, get onto Projector Central and send me an email.

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