The most common question heard when looking for a new projector for the home, office, or classroom is: would I purchase an LCD projector or a DLP projector? LCD, short for ‘liquid crystal device’ and DLP, standing for ‘digital light processing’ are the two most popular projector imaging technologies. With so many brands and models available, it can be overwhelming for consumers to make a decision between these technologies. The simple fact of the matter is that LCD projectors offer better image quality and colour accuracy. The next paragraph will tell you why DLP projectors struggle with reproducing a comparable standard of image quality.

It’s like a set of blinds in your home 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 works. Each pixel functions like a unique shutter on a set of blinds to either allow 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 functions to either reflect light or block it.

How the light source is processed from the point when the projector turns on to when the content reaches your screen is ultimately significant to image quality, brightness and colour accuracy. LCD projectors project white light from the lamp by separating it into red, blue and green components, by three mirrors which send the coloured light to 3 different LCD panels. The 3 LCD panels cast the elements of the image by shining each pixel on and off. The pixels are then combined in a glass prism to form the projector image. A point to know about LCD projectors is that all three colours are sent onto your screen simultaneously. The way a DLP projector runs is totally different and even the final product of how an image shows up is not the same. With DLP, white light from the lamp is sent through a turning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of forming an image casts a sequence of red, blue and green light. The millions of micro mirrors described above reflect the coloured light on the pixels to produce the image elements. The elements of the image are projected in sequence on the screen, one colour at a time. The viewer’s eyes will then pull together each coloured element of the image into a complete image. From LCD projectors, all colours are available all the time to offer the highest brightness and fantastic colour accuracy. In DLP, only one colour is available at a time, and so resulting in lower colour brightness and accuracy. Some DLP manufacturers have placed a white segment for the colour wheel to improve all over brightness, but this also lessens colour accuracy.

I hear in forums all the time that DLP gives a higher contrast ratio and therefore must be better quality. For those who are 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 capable of producing. DLP projectors do provide high contrast specifications compared to many LCD projectors. At a glance, this can seem to be a benefit, however, in real life, the true black level is determined by the ambient light in the room where the projector is in use. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you wish to see includes moving images, DLP projection technology can also create image imperfections, or ‘artifacts’. The most often seen 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 position between the time red, blue and green colours are displayed. LCD projectors do not have this problem because all the colours are processed with the others. DLP designers have formed 3DLP solutions using 3 chips to resolve the colour break up issue, but the expense of these projectors make them not practical for many businesses and consumers.

Another differentiation between LCD and DLP is how they balance for the refractive qualities of light. Take yourself back to high school science, and recall when they taught you how the different colours of light refract varied amounts when shone through the same lens. The problem 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 obviously not the same and refract light differently. Usually with a DLP projector, an extra yellow colour will show above and a superfluous blue will come through below an image of something as simple as a lone black line. While being built LCD projectors can be set to minimize these effects on the projected image, as each colour is projected on isolated LCD panels.

The only actual plus (excluding price) with deciding on a DLP projector is its overall smaller size and weight. However, this is only relevant for portability and must be traded off against the image superiority of LCD projectors. If overall picture quality is important to you, then the choice is no-brainer. Take an LCD projector! LCD projectors will always show bright, colourful images with fewer image mistakes. If you desire to find out more about LCD technology in more detail, see this fabulous resource website: Explore 3LCD. If you have any further questions, visit Projector Central and send me an email.

Jonathan King is the sales and marketing manager for Projector Central, Australia’s premier online store for projectors. Based in Brisbane, Projector Central has been serving Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.