Australian Content Blog

The typical question that is asked when acquiring a new projector for the home, office, or classroom is: should I take an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, standing for ‘digital light processing’ are the two most common projector imaging technologies. With so many different brands and different types available, it can be overwhelming for customers to choose between those technologies. Ultimately LCD projectors have superior image quality and colour accuracy. The next paragraph tells you why DLP projectors struggle with reproducing a comparable rate of image quality.

Imagine a set of blinds in your household on your bedroom window. With the twist of a rod you can make 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 operates like a single shutter on a set of blinds to either allow light through or to block it. DLP on the other hand is made up 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 point at which the projector is switched on to when the content reaches your screen is extremely 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 projected in a glass prism to deliver the projector image. A significant point to remember about LCD projectors is that all three colours are delivered onto your wall at once. The way a DLP projector works is vastly different and even the produced image looks is not the same. With DLP, white light from the lamp is processed through a spinning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This way 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 put together each coloured element of the image into the complete image. Using LCD projectors, all colours are available all the time to form top brightness and spectacular colour accuracy. In DLP, just one colour is available at once, resulting in lower colour brightness and accuracy. Some developers have put a white segment into the colour wheel to improve brightness overall, but this then damages colour accuracy.

I find in forums all the time that DLP has a higher contrast ratio and therefore 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 projector is able to produce. DLP projectors do provide high contrast specifications as compared to the majority of LCD projectors. At a glance, this must be a benefit, 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 wish to see has moving images, DLP projection technology can also create 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 between the time red, blue and green colours are pulled up. LCD projectors do not have this problem because all colours are processed at the same time. DLP builders have created 3DLP solutions using 3 chips to answer the colour break up error, but the expense of these projectors make them not practical for many businesses and consumers.

Another point of difference between LCD and DLP is how they make up for the refractive qualities of light. Jump back to high school science, and recall when they taught you how the various colours of light refract different amounts when passing through the same lens. The downfall 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 at different levels. Most of the time with a DLP projector, some yellow colour will show above and some extra blue will come up below an image of something as simple as a straight black line. In building LCD projectors can be adjusted to remove these effects on the projected image, as each colour is processed on separate LCD panels.

The sole true benefit (excluding price) with picking a DLP projector is its smaller size and weight. However, this is only relevant for portability and must be traded off against the image benefits of LCD projectors. If the outcome of the picture quality is vital to you, then the choice is no-brainer. Go with an LCD projector! LCD projectors will definitely make bright, colourful images with fewer image imperfections. If you want to find out more about LCD technology in more detail, have a gander at this fantastic resource website: Explore 3LCD. If you have any more questions, visit Projector Central and send me an email.

Jonathan King is the sales and marketing manager of Projector Central, Australia’s leading online retailer 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.