The most common question heard when buying a new projector for the home, office, or classroom is: will I buy an LCD projector or a DLP projector? LCD, an acronym for ‘liquid crystal device’ and DLP, an acronym for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many different brands and models available, it can be difficult for the buyer to pick between the two technologies. It comes down to the fact that LCD projectors offer superior image quality and colour accuracy. The next paragraph explains why DLP projectors struggle with creating a comparable standard of image quality.

Imagine a set of blinds in your house on your bedroom window. With the twist of a rod you can have the shutters open or closed, according to whether you want to let light in or not. And such is exactly how an LCD projector functions. 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 professionals like to call them. Each pixel element functions 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 absolutely important to image quality, brightness and colour accuracy. LCD projectors process white light from the lamp by splitting it into red, blue and green components, by three mirrors which direct the coloured light to 3 individual LCD panels. The 3 LCD panels make the elements of the image by turning each pixel on and off. The pixels are then combined in a glass prism to form the projector image. A point to understad about LCD projectors is that all three colours are directed onto your projected surface at the same time. The way a DLP projector operates is widely different and even how an 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 way of projecting an image casts a sequence of red, blue and green light. The millions of micro mirrors as 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 vision will then draw each coloured element of the image into a single whole image. With LCD projectors, all colours are available all the time to create top brightness and fantastic colour accuracy. In DLP, only one colour is available at a time, and so causing lower colour brightness and accuracy. Some DLP designers have included a white segment in the colour wheel to improve brightness overall, but this also damages colour accuracy.

I find in forums all the time that DLP has a higher contrast ratio and thus 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 machine is capable of producing. DLP projectors do possess high contrast specifications as compared to many LCD projectors. At one glance, this must be an advantage, however, in reality, the true black level is determined by the ambient light in the room when the projector is utilised. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you are trying to see includes moving images, DLP projection technology can also have image imperfections, or ‘artifacts’. The most common artifact that a DLP projector forms 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 the colours are projected simultaneously. DLP builders have developed 3DLP solutions using 3 chips to resolve the colour break up issue, but the price tag of these projectors make them not practical for the majority of businesses and consumers.

Another differentiation between LCD and DLP is how they make up for the refractive qualities of light. Jump back to high school science, and 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 different and refract light in a different way. Most of the time with a DLP projector, some yellow colour will be projected above and some blue will come through below an image of something as simple as a single black line. During manufacturing LCD projectors can be adapted to reduce these effects on the projected image, because each colour is projected on separate LCD panels.

The one actual advantage (excluding price) with choosing a DLP projector is its smaller size and weight. However, this is only relevant for mobility and needs to be traded off against the image plusses of LCD projectors. If overall picture quality is important to you, then the choice is easy. Go for an LCD projector! LCD projectors will always show bright, colourful images with fewer image errors. If you desire to learn more about LCD technology in more detail, have a gander at this tremendous resource website: Explore 3LCD. If you have any other questions, visit Projector Central and send me an email.

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