Mining Wise International

The most typical question heard when looking for a new projector for the home, office, or classroom is: would I take an LCD projector or a DLP projector? LCD, an acronym for ‘liquid crystal device’ and DLP, which stands for ‘digital light processing’ are the two most popular projector imaging technologies. With so many brands and models available, it can be challenging for the buyer to choose between those technologies. The simple fact of the matter is that LCD projectors give superior image quality and colour accuracy. The following article tells you why DLP projectors struggle with bringing up the same grade of image quality.

Imagine a set of blinds in your room covering your bedroom window. By pulling on a rod you can have the shutters open or closed, according to whether you want to let light in or not. That is exactly how an LCD projector behaves. 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 created of millions of microscopic mirrors or ‘pixel elements’ as the experts 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 picture reaches your screen is vitally significant for image quality, brightness and colour accuracy. LCD projectors project white light from the lamp by separating it into red, blue and green components, by three mirrors which direct the coloured light to 3 individual LCD panels. The 3 LCD panels cast the elements of the image by turning each pixel on and off. The pixels are then meshed in a glass prism to deliver the projector image. A significant point to understad about LCD projectors is that all three colours are delivered onto your screen simultaneously. The way a DLP projector works is vastly different and even the produced image shows up is not the same. With DLP, white light from the lamp is directed 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 forms a sequence of red, blue and green light. The millions of micro mirrors as mentioned above reflect the coloured light on the pixels to form 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 combine each coloured element of the image into the single complete image. From LCD projectors, all colours are available all the time to form top brightness and fantastic colour accuracy. In DLP, just one colour is available at a time, causing lower colour brightness and accuracy. Some DLP developers have added a white segment into the colour wheel to improve brightness overall, but this also damages colour accuracy.

I see in forums all the time that DLP provides a higher contrast ratio and therefore must be superior. For those who do not 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 technology is capable of producing. DLP projectors do have high contrast specifications when compared to most LCD projectors. Initially, this seems to be a benefit, however, in real life, the true black level is determined by the ambient light in the room when 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 has moving images, DLP projection technology can also create image imperfections, or ‘artifacts’. The most often seen artifact that a DLP projector shows with moving images is colour break up. Colour break up is to be expected in DLP systems because moving images change between the time red, blue and green colours are shone. LCD projectors do not have this downside because all colours are sent at once. DLP designers have created 3DLP solutions using 3 chips to fix the colour break up artifacts, but the cost of these projectors make them hardly practical for the majority of businesses and consumers.

Another variance between LCD and DLP is how they compensate for the refractive qualities of light. Think back to high school science, and they taught you how different colours of light refract different amounts when passing through the same lens. The disadvantage 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 obviously not the same and refract light differently. Usually with a DLP projector, a spill of yellow colour will show above and some blue will show below an image of something as simple as a single black line. In building LCD projectors can be fixed to reduce these effects on the projected image, because each colour is directed on a separate LCD panels.

The sole veritable advantage (excluding price) with buying a DLP projector is its smaller total size and weight. However, this is only relevant in regard to portability and must be traded off against the image advantages of LCD projectors. If overall picture quality is crucial to you, then the solution is easy. Choose an LCD projector! LCD projectors will constantly make bright, colourful images with fewer image mistakes. If you want to ask more about LCD technology in more detail, check out this fabulous resource website: Explore 3LCD. If you have any more questions, go to Projector Central and send me an email.

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