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The most typical question asked when buying a new projector for the home, office, or classroom is: should I take an LCD projector or a DLP projector? LCD, short for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many company brands and different types available, it can be difficult for the buyer to choose between both technologies. The fact is that LCD projectors provide better image quality and colour accuracy. The article below will tell you why DLP projectors struggle with creating an equal grade of image quality.

Imagine a set of blinds in your home covering your bedroom window. By pulling on a rod you can have the shutters open or closed, depending on whether you want to let light in or not. This is exactly how an LCD projector works. Each pixel works like its own shutter on a set of blinds to either pass light through or to block it. DLP on the other hand is constructed of millions of microscopic mirrors or ‘pixel elements’ as the pros like to call them. Each pixel element operates to either reflect light or block it.

How the light source is processed from when the projector switches on to when the content reaches your screen is absolutely significant for image quality, brightness and colour accuracy. LCD projectors shine white light from the lamp by separating it into red, blue and green components, by three mirrors which project the coloured light to 3 different LCD panels. The 3 LCD panels create the elements of the image by shining each pixel on and off. The pixels are then meshed in a glass prism to deliver the projector image. A point to realise about LCD projectors is that all three colours are directed onto your wall simultaneously. The way a DLP projector operates is very different and even how an image looks is not the same. With DLP, white light from the lamp is processed through a turning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This approach to creating an image requires 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 displayed in sequence on the screen, one colour at a time. The viewer’s vision will then draw each coloured element of the image into a single whole image. From LCD projectors, all colours are available all the time to create the best brightness and superb colour accuracy. In DLP, only one colour is available at a time, causing lower colour brightness and accuracy. Some designers have included a white segment in the colour wheel to improve all over brightness, but this then detracts from colour accuracy.

I read in forums all the time that DLP offers a higher contrast ratio and as such must be superior. 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 machine is able to produce. DLP projectors do have high contrast specifications compared to many LCD projectors. At a glance, this seems to be a plus, however, in the real world, the true black level is determined by the ambient light in the room while the projector is being used. Do not be fooled by contrast specifications on websites and in brochures.

When the content you want to see has moving images, DLP projection technology also creates 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 to be expected in DLP systems because moving images change up between the time red, blue and green colours are pulled up. LCD projectors do not have this disadvantage because the colours are sent at once. DLP developers have developed 3DLP solutions using 3 chips to resolve the colour break up error, but the cost of these projectors make them hardly practical for the majority of businesses and consumers.

Another point of difference between LCD and DLP is how they match the balance for the refractive qualities of light. Think back to high school science, and recall when they taught you how the different colours of light refract different amounts when passing through the same lens. The downside 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 different and refract light in a different way. Generally with a DLP projector, a superfluous yellow colour will show above and some blue will be projected below an image of something as simple as a single black line. During manufacturing LCD projectors can be fixed to minimize these effects on the projected image, because each colour is projected on isolated LCD panels.

The one actual buy point (excluding price) with deciding on a DLP projector is its smaller total 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 important to you, then the decision is simple. Take an LCD projector! LCD projectors will always 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 tremendous resource website: Explore 3LCD. If you have any additional 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. Based in Brisbane, Projector Central has been serving Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.