The common question customers ask when purchasing a new projector for the home, office, or classroom is: will I purchase 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 different brands and models available, it can be difficult for clients to decide between both technologies. The fact is that LCD projectors provide superior image quality and colour accuracy. The next paragraph explains why DLP projectors struggle with bringing up an equal rate of image quality.

Think of a set of blinds in your house for your bedroom window. By a twist of a rod you can have the shutters open or closed, depending on if you want to let light in or not. That is exactly how an LCD projector operates. Each pixel works like a single shutter on a set of blinds to either send 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 operates to either reflect light or block it.

How the light source is processed from when the projector is switched on to when the picture reaches your screen is ultimately important for image quality, brightness and colour accuracy. LCD projectors direct white light from the lamp by cutting it into red, blue and green components, by three mirrors which send the coloured light to 3 individual LCD panels. The 3 LCD panels make the elements of the image by shining each pixel on and off. The pixels are then projected in a glass prism to create the projector image. An important point to know about LCD projectors is that all three colours are projected onto your screen all at the same time. The way a DLP projector runs is vastly different and even the produced image appears is not the same. With DLP, white light from the lamp is processed through a rotating colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This approach to forming 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 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 draw each coloured element of the image into a total image. With LCD projectors, all colours are available all the time to form the top level of brightness and fantastic colour accuracy. In DLP, only one colour is available at once, causing lower colour brightness and accuracy. Some developers have put a white segment in the colour wheel to improve general brightness, but this then damages colour accuracy.

I read in forums all the time that DLP provides a higher contrast ratio and ergo must be superior quality. 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 system is able to produce. DLP projectors do have high contrast specifications as compared to most LCD projectors. At first glance, this seems to be a benefit, however, in truth, the true black level is determined by the ambient light in the room when the projector is used. Do not be fooled by contrast specifications on websites and in brochures.

When the content you want to bring to life includes moving images, DLP projection technology can also create image marks, or ‘artifacts’. The most commonplace artifact that a DLP projector creates with moving images is colour break up. Colour break up is unavoidable in DLP systems because moving images change up between the time red, blue and green colours are displayed. LCD projectors do not have this disadvantage because all the colours are projected with the others. DLP developers have formed 3DLP solutions using 3 chips to resolve the colour break up problem, but the price of these projectors make them not practical for the majority of businesses and consumers.

Another differentiation between LCD and DLP is how they balance for the refractive qualities of light. Think back to high school science, and recall when they taught you how various colours of light refract differing amounts when shone through the same lens. The downfall 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 different and refract light in different ways. Often with a DLP projector, a spill of yellow colour will come through above and some blue will be projected below an image of something as simple as a lone black line. In manufacturing LCD projectors can be set to reduce these effects on the projected image, because each colour is refracted on its own LCD panels.

The only true benefit (excluding price) with going with a DLP projector is its smaller overall size and weight. However, this is only relevant in regard to transporting the device and has to be traded off against the image plusses of LCD projectors. If resulting picture quality is important to you, then the choice is a no-brainer. Take an LCD projector! LCD projectors will consistently make bright, colourful images with fewer image blips. If you need 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 with Projector Central, Australia’s leading online shop for projectors. Brisbane-based, Projector Central has served Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.