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The most typical question customers ask when looking for a new projector for the home, office, or classroom is: do I get an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many brands and types available, it can be challenging for consumers to choose between both technologies. The fact is that LCD projectors provide better image quality and colour accuracy. The following article tells you why DLP projectors struggle with reproducing a comparable grade of image quality.

It’s like a set of blinds in your home for your bedroom window. By pulling a rod you can make the shutters open or closed, according to if you want to let light in or not. This is exactly how an LCD projector behaves. 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 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 when the projector is switched on to when the picture reaches your screen is vitally significant 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 direct 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 projected in a glass prism to send the projector image. An important point to realise about LCD projectors is that all three colours are projected onto your screen at the same time. The way a DLP projector functions is vastly 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 method of creating an image creates a sequence of red, blue and green light. The millions of micro mirrors 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 vision will then put together each coloured element of the image into a complete image. In LCD projectors, all colours are available all the time to deliver top brightness and great colour accuracy. In DLP, only one colour is available at any given time, and so causing lower colour brightness and accuracy. Some DLP designers have placed a white segment for the colour wheel to improve overall brightness, but this goes and detracts from colour accuracy.

I find in forums all the time that DLP gives a higher contrast ratio and ergo must be better. For those who don’t know, 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 offer high contrast specifications as compared to most LCD projectors. At one glance, this seems to 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 used. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you are trying to project has moving images, DLP projection technology can also create image imperfections, or ‘artifacts’. The most common artifact that a DLP projector displays with moving images is colour break up. Colour break up is to be expected in DLP systems because moving images change between the time red, blue and green colours are displayed. LCD projectors do not have this characteristic because the colours are processed with the others. DLP builders have come up with 3DLP solutions using 3 chips to resolve the colour break up error, but the cost of these projectors make them impractical for most 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 they taught you how various colours of light refract varied amounts when projected through the same lens. The disadvantage with DLP projectors is that they have the one same panel with the same lens to project Red, Blue and Green. All 3 colours are not the same and refract light differently. Generally with a DLP projector, an extra yellow colour will come through above and a spill of blue will show below an image as simple as a lone black line. During manufacturing LCD projectors can be set to minimize these effects on the projected image, as each colour is processed on a separate LCD panels.

The only actual advantage (excluding price) with buying a DLP projector is its overall smaller size and weight. However, this is only relevant for portability and needs to be traded off against the image plusses of LCD projectors. If overall picture quality is vital to you, then the solution is a no-brainer. Go for an LCD projector! LCD projectors will constantly create bright, colourful images with fewer image imperfections. If you desire to ask more about LCD technology in more detail, see this spectacular resource website: Explore 3LCD. If you have any more questions, go to Projector Central and send me an email.

Jonathan King is the sales and marketing manager with Projector Central, Australia’s number one online store for projectors. Brisbane based, Projector Central has served Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.