The most typical question asked when acquiring a new projector for the home, office, or classroom is: do I take an LCD projector or a DLP projector? LCD, an acronym for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two most popular projector imaging technologies. With so many different brands and types available, it can be overwhelming for customers to pick between those technologies. Ultimately LCD projectors have far better image quality and colour accuracy. The following article will tell you why DLP projectors struggle with projecting an equal level of image quality.

It’s like a set of blinds in your home for your bedroom window. By pulling a rod you can turn the shutters open or closed, depending on whether you want to let light in or not. And that is exactly how an LCD projector operates. Each pixel works 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 pros 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 extremely important for image quality, brightness and colour accuracy. LCD projectors process white light from the lamp by separating it into red, blue and green components, by three mirrors which transfer the coloured light to 3 stand alone LCD panels. The 3 LCD panels cast the elements of the image by processing each pixel on and off. The pixels are then projected in a glass prism to send the projector image. An important point to know about LCD projectors is that all three colours are directed onto your screen at the same time. The way a DLP projector operates is very different and even the way an image shows up 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 forming 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 construct 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 full image. Using LCD projectors, all colours are available all the time to deliver the top level of brightness and superb colour accuracy. In DLP, just one colour is available at a time, resulting in lower colour brightness and accuracy. Some manufacturers have included a white segment into the colour wheel to improve brightness overall, but this also damages colour accuracy.

I find in forums all the time that DLP offers a higher contrast ratio and thus must be superior quality. For those unaware, 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 machine is capable of. DLP projectors do provide high contrast specifications as compared to a majority of LCD projectors. At first glance, this must be a plus, however, in reality, the true black level is determined by the ambient light in the room in which the projector is being used. Do not be tricked by contrast specifications on websites and in brochures.

When the content you are trying to view requires moving images, DLP projection technology can also create image marks, or ‘artifacts’. The most common artifact that a DLP projector shows with moving images is colour break up. Colour break up is incontrovertible in DLP systems because moving images change between the time red, blue and green colours are shone. LCD projectors do not have this problem because all colours are delivered at the same time. DLP designers have developed 3DLP solutions using 3 chips to fix the colour break up problem, but the price tag of these projectors make them impractical for the large part of businesses and consumers.

Another variance between LCD and DLP is how they match the balance for the refractive qualities of light. Remember back to high school science, and remember when they taught you how the various colours of light refract different amounts when directed through the same lens. The problem 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 different ways. Generally with a DLP projector, an extra yellow colour will appear above and some extra blue will come up below something as simple as a single black line. During manufacturing LCD projectors can be adjusted to take away these effects on the projected image, as each colour is refracted on its own LCD panels.

The one real buy point (excluding price) with deciding on a DLP projector is its smaller size and weight. However, this is only relevant to transport and must be traded off against the image superiority of LCD projectors. If the outcome of the picture quality is vital to you, then the answer is simple. Choose an LCD projector! LCD projectors will definitely make bright, colourful images with fewer image errors. If you need to ask more about LCD technology in more detail, have a look at this spectacular resource website: Explore 3LCD. If you have any persisting questions, visit Projector Central and send me an email.

Jonathan King is the sales and marketing manager with Projector Central, Australia’s premier online provider for projectors. Based in Brisbane, Projector Central has serviced Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.