Mack and Mark

The most typical question customers ask when purchasing a new projector for the home, office, or classroom is: do 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 most popular projector imaging technologies. With so many business brands and models available, it can be challenging for clients to make a decision between both technologies. The simple fact of the matter is that LCD projectors have far better image quality and colour accuracy. The next paragraph tells you why DLP projectors struggle with creating a comparable grade of image quality.

Visualise a set of blinds in your home on your bedroom window. By pulling a rod you can turn the shutters open or closed, according to whether you want to let light in or not. Such is exactly how an LCD projector functions. Each pixel functions like its own shutter on a set of blinds to either send 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 at which 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 shine white light from the lamp by dividing 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 switching each pixel on and off. The pixels are then meshed in a glass prism to send the projector image. Something important to realise about LCD projectors is that all three colours are sent onto your projected surface at once. The way a DLP projector works is widely different and even the final product of how an image appears 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 creates a sequence of red, blue and green light. The millions of micro mirrors as mentioned 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 eye will then draw each coloured element of the image into the whole image. With LCD projectors, all colours are available all the time to offer the best brightness and great colour accuracy. In DLP, just one colour is available at any given time, and so causing lower colour brightness and accuracy. Some DLP manufacturers have placed a white segment into the colour wheel to improve general brightness, but this then degrades colour accuracy.

I see in forums all the time that DLP offers a higher contrast ratio and ergo must be superior. For those 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 technology is capable of producing. DLP projectors do have high contrast specifications when compared to a majority of LCD projectors. At one 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 being used. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you want to bring to life needs moving images, DLP projection technology can also create image imperfections, or ‘artifacts’. The most often seen artifact that a DLP projector displays with moving images is colour break up. Colour break up is inherent in DLP systems because moving images keep changing between the time red, blue and green colours are pulled up. LCD projectors do not have this downside because the colours are sent at the same time. DLP manufacturers have come up with 3DLP solutions using 3 chips to fix the colour break up issue, but the price tag of these projectors make them hardly practical for the large part of businesses and consumers.

Another point of difference between LCD and DLP is how they make up for the refractive qualities of light. Take yourself back to high school science, and they taught you how different colours of light refract differing amounts when directed through the same lens. The downfall with DLP projectors is that they have the one same panel for the same lens to project Red, Blue and Green. All 3 colours are not the same and refract light in a different way. Generally with a DLP projector, some yellow colour will come up above and some blue will show below an image of something as simple as a straight black line. In building LCD projectors can be set to take away these effects on the projected image, because each colour is refracted on its own LCD panels.

The isolated true benefit (excluding price) with choosing a DLP projector is its overall smaller size and weight. However, this is only relevant with regard to transport and cannot be traded off against the image benefits of LCD projectors. If the result of the picture quality is crucial to you, then the solution is easy. Choose an LCD projector! LCD projectors will constantly create bright, colourful images with fewer image mistakes. If you desire to know more about LCD technology in more detail, check out this tremendous resource website: Explore 3LCD. If you have any other questions, get onto Projector Central and send me an email.

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