The most typical question customers ask when buying a new projector for the home, office, or classroom is: will I buy an LCD projector or a DLP projector? LCD, standing for ‘liquid crystal device’ and DLP, which stands for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many brands and types available, it can be difficult for customers to decide between those technologies. It comes down to the fact that LCD projectors have better image quality and colour accuracy. The article below will tell you why DLP projectors struggle with projecting an equal rate of image quality.

It’s like a set of blinds in your house for your bedroom window. With the twist of a rod you can have the shutters open or closed, according to if you want to let light in or not. And that is exactly how an LCD projector functions. Each pixel works like its own shutter on a set of blinds to either send light through or to block it. DLP on the other hand is constructed of millions of microscopic mirrors or ‘pixel elements’ as the professionals 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 switches on to when the picture reaches your screen is extremely important for 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 individual LCD panels. The 3 LCD panels create the elements of the image by processing each pixel on and off. The pixels are then projected in a glass prism to create the projector image. Something to remember about LCD projectors is that all three colours are projected onto your projector screen all at once. The way a DLP projector works is widely different and even how an image looks is not the same. With DLP, white light from the lamp is projected through a spinning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of making an image requires a sequence of red, blue and green light. The millions of micro mirrors as described above reflect the coloured light on the pixels to form the image elements. The elements of the image are sent in sequence on the screen, one colour at a time. The viewer’s vision will then draw each coloured element of the image into the single full image. In LCD projectors, all colours are available all the time to form top brightness and great colour accuracy. In DLP, only one colour is available at a time, causing lower colour brightness and accuracy. Some designers have placed a white segment for the colour wheel to improve general brightness, but this goes and damages colour accuracy.

I find in forums all the time that DLP provides a higher contrast ratio and as such must be superior quality. For those who are 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 system is capable of producing. DLP projectors do have high contrast specifications when compared to most LCD projectors. At a glance, this must be an advantage, however, in real life, the true black level is determined by the ambient light in the room in which the projector is used. Do not be tricked by contrast specifications on websites and in brochures.

When the content you plan to see has moving images, DLP projection technology also creates image imperfections, or ‘artifacts’. The most commonplace artifact that a DLP projector displays 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 displayed. LCD projectors do not have this problem because the colours are processed with the others. DLP designers have formed 3DLP solutions using 3 chips to answer the colour break up problem, but the price tag of these projectors make them impractical for most businesses and consumers.

Another difference between LCD and DLP is how they compensate for the refractive qualities of light. Take yourself back to high school science, and they taught you how the different colours of light refract varied amounts when projected through the same lens. The downside with DLP projectors is that they take the one same panel and the same lens to project Red, Blue and Green. All 3 colours are different and refract light differently. Generally with a DLP projector, a spill of yellow colour will come through above and an extra blue will be projected below an image as simple as a single black line. While being built LCD projectors can be set to minimize these effects on the projected image, because each colour is refracted on isolated LCD panels.

The one true benefit (excluding price) with taking a DLP projector is its smaller total size and weight. However, this is only relevant to portability and must be traded off against the image advantages of LCD projectors. If the outcome of the picture quality is important to you, then the decision is no-brainer. Take an LCD projector! LCD projectors will always make bright, colourful images with fewer image mistakes. If you want to learn more about LCD technology in more detail, have a look at this fantastic resource website: Explore 3LCD. If you have any additional questions, jump onto Projector Central and send me an email.

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