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The most common question customers ask when buying a new projector for the home, office, or classroom is: would I purchase an LCD projector or a DLP projector? LCD, standing for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many different brands and different types available, it can be challenging for the buyer to pick between both technologies. The simple fact of the matter is that LCD projectors give far superior image quality and colour accuracy. The following article will explain why DLP projectors struggle with bringing up a comparable standard of image quality.

It’s like a set of blinds in your room covering your bedroom window. By a twist of a rod you can turn the shutters open or closed, depending on if you want to let light in or not. This is exactly how an LCD projector behaves. Each pixel works like its own shutter on a set of blinds to either allow light through or to block it. DLP on the other hand is formed of millions of microscopic mirrors or ‘pixel elements’ as the pros like to call them. Each pixel element works to either reflect light or block it.

How the light source is processed from the time the projector is turned on to when the picture reaches your screen is ultimately 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 project the coloured light to 3 stand alone LCD panels. The 3 LCD panels cast the elements of the image by switching each pixel on and off. The pixels are then combined in a glass prism to send the projector image. A significant point to know about LCD projectors is that all three colours are directed onto your wall at once. The way a DLP projector operates is widely different and even the way an image shows up 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 method 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 construct the image elements. The elements of the image are displayed 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 single full image. From LCD projectors, all colours are available all the time to deliver high brightness and great colour accuracy. In DLP, just one colour is available at a time, causing 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 read in forums all the time that DLP has a higher contrast ratio and thus 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 system is able to produce. DLP projectors do possess high contrast specifications in comparison to the majority of LCD projectors. At a glance, this must be an advantage, however, in real life, the true black level is determined by the ambient light in the room when the projector is in use. Do not be duped by contrast specifications on websites and in brochures.

When the content you plan to project includes moving images, DLP projection technology can also create image errors, or ‘artifacts’. The most often seen artifact that a DLP projector creates with moving images is colour break up. Colour break up is inherent in DLP systems because moving images change position between the time red, blue and green colours are displayed. LCD projectors do not have this downside because every colour is delivered at the same time. DLP designers have formed 3DLP solutions using 3 chips to resolve the colour break up problem, but the cost of these projectors make them hardly practical for most businesses and consumers.

Another differentiation between LCD and DLP is how they compensate for the refractive qualities of light. Remember back to high school science, and remember when they taught you how the various colours of light refract differing amounts when shone through the same lens. The problem with DLP projectors is that they take the one same panel and the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light in different ways. Most of the time with a DLP projector, a superfluous yellow colour will come through above and an extra blue will be projected below something as simple as a single black line. During manufacturing LCD projectors can be adapted to minimize these effects on the projected image, as each colour is processed on isolated LCD panels.

The one real benefit (excluding price) with buying a DLP projector is its smaller size and weight. However, this is only relevant with regard to transporting the device and cannot be traded off against the image benefits of LCD projectors. If overall picture quality is vital to you, then the choice is simple. Go for an LCD projector! LCD projectors will always create bright, colourful images with fewer image mistakes. If you need to know more about LCD technology in more detail, see this spectacular resource website: Explore 3LCD. If you have any additional questions, jump onto 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 been serving Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.