Australian Content Blog

The common question asked when purchasing a new projector for the home, office, or classroom is: do I purchase an LCD projector or a DLP projector? LCD, short for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two most popular projector imaging technologies. With so many brands and types available, it can be overwhelming for clients to pick between these technologies. Ultimately LCD projectors give better image quality and colour accuracy. The article below will tell you why DLP projectors struggle with reproducing the same rate of image quality.

Think of a set of blinds in your room for 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. And this is exactly how an LCD projector behaves. Each pixel works like a single shutter on a set of blinds to either pass light through or to block it. DLP on the other hand is constructed of millions of microscopic mirrors or ‘pixel elements’ as the experts 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 is switched on to when the image reaches your screen is absolutely important with regard to image quality, brightness and colour accuracy. LCD projectors direct white light from the lamp by splitting it into red, blue and green components, by three mirrors which transfer the coloured light to 3 different LCD panels. The 3 LCD panels make 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. Something to understad about LCD projectors is that all three colours are delivered onto your wall simultaneously. The way a DLP projector works is widely different and even the produced image comes out is not the same. With DLP, white light from the lamp is projected through a turning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of forming an image forms a sequence of red, blue and green light. The millions of micro mirrors as described above reflect the coloured light on the pixels to construct the image elements. The elements of the image are projected 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. From LCD projectors, all colours are available all the time to deliver high brightness and superb colour accuracy. In DLP, only one colour is available at a time, and so causing lower colour brightness and accuracy. Some DLP designers have added a white segment into the colour wheel to improve general brightness, but this then detracts from colour accuracy.

I hear in forums all the time that DLP offers a higher contrast ratio and as such must be superior quality. For those who don’t 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 possess high contrast specifications compared to a majority of LCD projectors. At one glance, this seems to be an advantage, however, in reality, the true black level is determined by the ambient light in the room when the projector is in use. Do not be tricked by contrast specifications on websites and in brochures.

When the content you are trying to bring to life has moving images, DLP projection technology also creates image errors, or ‘artifacts’. The most commonplace artifact that a DLP projector shows with moving images is colour break up. Colour break up is inherent in DLP systems because moving images change up between the time red, blue and green colours are shone. LCD projectors do not have this downside because every colour is projected at the same time. DLP developers have formed 3DLP solutions using 3 chips to solve the colour break up issue, but the cost of these projectors make them impractical for many businesses and consumers.

Another differentiation 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 the various colours of light refract varied amounts when projected through the same lens. The disadvantage with DLP projectors is that they utilise the one same panel with the same lens to project Red, Blue and Green. All 3 colours are different and refract light in different ways. Generally with a DLP projector, some yellow colour will come up above and some blue will come through below something as simple as a single black line. In manufacturing LCD projectors can be adapted to minimize these effects on the projected image, as each colour is refracted on a separate LCD panels.

The sole true buy point (excluding price) with picking a DLP projector is its smaller overall size and weight. However, this is only relevant with regard to portability and has to be traded off against the image superiority of LCD projectors. If overall picture quality is important to you, then the answer is no-brainer. Choose an LCD projector! LCD projectors will constantly create bright, colourful images with fewer image mistakes. If you wish to learn more about LCD technology in more detail, have a gander at this spectacular resource website: Explore 3LCD. If you have any persisting questions, go to Projector Central and send me an email.

Jonathan King is the sales and marketing manager for Projector Central, Australia’s number one 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.