Australian Content Blog

The common question that is asked when looking for a new projector for the home, office, or classroom is: would I buy an LCD projector or a DLP projector? LCD, short for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two most common projector imaging technologies. With so many company brands and different types available, it can be difficult for customers to make a choice between these technologies. Ultimately LCD projectors provide far superior image quality and colour accuracy. The next paragraph explains why DLP projectors struggle with projecting an equal standard of image quality.

Imagine a set of blinds in your room for your bedroom window. With the twist of a rod you can make the shutters open or closed, depending on whether you want to let light in or not. That is exactly how an LCD projector operates. Each pixel functions like a single shutter on a set of blinds to either shine light through or to block it. DLP on the other hand is made up of millions of microscopic mirrors or ‘pixel elements’ as experts like to call them. Each pixel element functions to either reflect light or block it.

How the light source is processed from the point when the projector switches on to when the picture reaches your screen is absolutely significant with regard to image quality, brightness and colour accuracy. LCD projectors process white light from the lamp by separating it into red, blue and green components, by three mirrors which direct the coloured light to 3 individual LCD panels. The 3 LCD panels cast the elements of the image by turning each pixel on and off. The pixels are then meshed in a glass prism to send the projector image. An important point to understad about LCD projectors is that all three colours are sent onto your screen at the same time. The way a DLP projector works is totally different and even how an image shows up is not the same. With DLP, white light from the lamp is sent through a rotating colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of forming 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 projected in sequence on the screen, one colour at a time. The viewer’s eye will then combine each coloured element of the image into the single complete image. With LCD projectors, all colours are available all the time to offer the highest brightness and great colour accuracy. In DLP, only one colour is available at a time, and so causing lower colour brightness and accuracy. Some designers have included a white segment into the colour wheel to improve all over brightness, but this further degrades colour accuracy.

I hear in forums all the time that DLP offers a higher contrast ratio and as such must be better. For those unsure, 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 when compared to many LCD projectors. At first glance, this appears to 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 utilised. Do not be tricked by contrast specifications on websites and in brochures.

When the content you plan to view has moving images, DLP projection technology also creates image marks, or ‘artifacts’. The most often seen artifact that a DLP projector shows with moving images is colour break up. Colour break up is to be expected in DLP systems because moving images change up between the time red, blue and green colours are displayed. LCD projectors do not have this characteristic because every colour is sent at the same time. DLP builders have developed 3DLP solutions using 3 chips to fix the colour break up error, but the price tag of these projectors make them hardly practical 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 recall when they taught you how the various colours of light refract differing amounts when directed through the same lens. The downfall with DLP projectors is that they use the one same panel and the same lens to project Red, Blue and Green. All 3 colours are different and refract light differently. Most of the time with a DLP projector, some extra yellow colour will come up above and a superfluous blue will come through below an image as simple as a single black line. While being built LCD projectors can be fixed to remove these effects on the projected image, because each colour is directed on a separate LCD panels.

The only real plus (excluding price) with taking a DLP projector is its smaller size and weight. However, this is only relevant for transporting the device and cannot be traded off against the image advantages of LCD projectors. If the result of the picture quality is crucial to you, then the decision is easy. Choose an LCD projector! LCD projectors will consistently create bright, colourful images with fewer image mistakes. If you need to ask more about LCD technology in more detail, see this fabulous resource website: Explore 3LCD. If you have any additional questions, visit Projector Central and send me an email.

Jonathan King is the sales and marketing manager at Projector Central, Australia’s premier 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.