Social Media Army

The common question that is asked when buying a new projector for the home, office, or classroom is: will I get an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, which stands for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many business brands and types available, it can be confusing for clients to pick between the two technologies. The fact is that LCD projectors give far superior image quality and colour accuracy. The next part of this article tells you why DLP projectors struggle with projecting the same standard of image quality.

Visualise a set of blinds in your room over your bedroom window. By pulling a rod you can make the shutters open or closed, according to if you want to let light in or not. And such is exactly how an LCD projector operates. Each pixel operates like a unique 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 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 switches on to when the picture reaches your screen is vitally significant in regard to image quality, brightness and colour accuracy. LCD projectors project white light from the lamp by cutting it into red, blue and green components, by three mirrors which direct the coloured light to 3 stand alone 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 send the projector image. An important point to realise about LCD projectors is that all three colours are delivered onto your screen all at once. The way a DLP projector functions is widely different and even how an 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 way of making an image creates a sequence of red, blue and green light. The millions of micro mirrors described 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 eyes will then combine each coloured element of the image into the total image. From LCD projectors, all colours are available all the time to create high brightness and fantastic colour accuracy. In DLP, just one colour is available at a time, and so causing lower colour brightness and accuracy. Some designers have put a white segment into the colour wheel to improve brightness overall, but this then damages colour accuracy.

I find in forums all the time that DLP has a higher contrast ratio and therefore must be superior. For those who are 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 machine is capable of. DLP projectors do offer high contrast specifications when compared to most LCD projectors. At first glance, this must be an advantage, however, in real life, the true black level is determined by the ambient light in the room where the projector is being utilised. Do not be tricked by contrast specifications on websites and in brochures.

When the content you want to bring to life requires moving images, DLP projection technology can also create image marks, or ‘artifacts’. The most typical artifact that a DLP projector creates with moving images is colour break up. Colour break up is inherent in DLP systems because moving images change position between the time red, blue and green colours are displayed. LCD projectors do not have this problem because all the colours are projected at the same time. DLP manufacturers have created 3DLP solutions using 3 chips to resolve the colour break up issue, but the cost of these projectors make them impractical for many businesses and consumers.

Another variance between LCD and DLP is how they make up for the refractive qualities of light. Take yourself back to high school science, and recall how various colours of light refract varied amounts when passing through the same lens. The disadvantage with DLP projectors is that they have the one same panel and the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light in different ways. Usually with a DLP projector, a superfluous yellow colour will be projected above and some blue will come up below an image of something as simple as a lone black line. While being built LCD projectors can be set to remove these effects on the projected image, as each colour is directed on isolated LCD panels.

The one real buy point (excluding price) with taking a DLP projector is its smaller total size and weight. However, this is only relevant for transport and has to be traded off against the image plusses of LCD projectors. If resulting picture quality is crucial to you, then the answer is easy. Choose an LCD projector! LCD projectors will constantly make bright, colourful images with fewer image mistakes. If you need to know more about LCD technology in more detail, have a look at this fabulous resource website: Explore 3LCD. If you have any further questions, jump onto Projector Central and send me an email.

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