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The typical question that is asked when looking for a new projector for the home, office, or classroom is: should I buy 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 most common projector imaging technologies. With so many different brands and types available, it can be challenging for customers to make a decision between these technologies. Ultimately LCD projectors offer far superior image quality and colour accuracy. The following article will explain why DLP projectors struggle with reproducing a comparable rate of image quality.

Visualise a set of blinds in your room covering your bedroom window. By twisting a rod you can make the shutters open or closed, depending on whether you want to let light in or not. And that is exactly how an LCD projector works. Each pixel functions like an individual shutter on a set of blinds to either pass light through or to block it. DLP on the other hand is formed 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 point when the projector is turned on to when the picture reaches your screen is absolutely important 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 transfer the coloured light to 3 different LCD panels. The 3 LCD panels cast the elements of the image by switching each pixel on and off. The pixels are then simultaneously processed in a glass prism to form the projector image. A significant point to understad about LCD projectors is that all three colours are directed onto your wall all at once. The way a DLP projector operates is widely different and even the way an image looks 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 method of creating an image requires a sequence of red, blue and green light. The millions of micro mirrors described above reflect the coloured light on the pixels to create the image elements. The elements of the image are cast in sequence on the screen, one colour at a time. The viewer’s eye will then draw each coloured element of the image into a whole image. In LCD projectors, all colours are available all the time to create the top level of brightness and spectacular colour accuracy. In DLP, just one colour is available at a time, causing lower colour brightness and accuracy. Some designers have placed a white segment for the colour wheel to improve brightness generally, but this then lessens colour accuracy.

I hear in forums all the time that DLP has a higher contrast ratio and ergo must be superior. For those 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 offer high contrast specifications in comparison to many LCD projectors. At a glance, this can seem to 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 plan to view has moving images, DLP projection technology also creates image imperfections, or ‘artifacts’. The most commonplace artifact that a DLP projector displays with moving images is colour break up. Colour break up is to be expected in DLP systems because moving images change up between the time red, blue and green colours are shone. LCD projectors do not have this disadvantage because every colour is delivered simultaneously. DLP builders have developed 3DLP solutions using 3 chips to solve the colour break up problem, but the price tag of these projectors make them almost impossible for many businesses and consumers.

Another difference between LCD and DLP is how they compensate for the refractive qualities of light. Remember back to high school science, and remember when they taught you how various colours of light refract different amounts when projected through the same lens. The downfall 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 obviously different and refract light differently. Usually with a DLP projector, a spill of yellow colour will appear above and a superfluous blue will appear below an image containing something as simple as a straight black line. In building LCD projectors can be adapted to reduce these effects on the projected image, as each colour is directed on its own LCD panels.

The one true buy point (excluding price) with going with a DLP projector is its smaller overall size and weight. However, this is only relevant for mobility and must be traded off against the image plusses of LCD projectors. If resulting picture quality is important to you, then the decision is easy. Go for an LCD projector! LCD projectors will definitely show bright, colourful images with fewer image errors. If you want to learn more about LCD technology in more detail, see this fabulous resource website: Explore 3LCD. If you have any more questions, get onto Projector Central and send me an email.

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

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