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The most typical question asked when buying a new projector for the home, office, or classroom is: will I buy an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, an acronym for ‘digital light processing’ are the two most popular projector imaging technologies. With so many company brands and different types available, it can be difficult for consumers to decide between these technologies. It comes down to the fact that LCD projectors provide superior image quality and colour accuracy. The next paragraph will explain why DLP projectors struggle with reproducing an equal grade of image quality.

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

How the light source is processed from the point when the projector is turned on to when the content reaches your screen is absolutely significant for image quality, brightness and colour accuracy. LCD projectors direct white light from the lamp by cutting it into red, blue and green components, by three mirrors which transfer the coloured light to 3 stand alone LCD panels. The 3 LCD panels make the elements of the image by switching each pixel on and off. The pixels are then projected in a glass prism to form the projector image. Something to know about LCD projectors is that all three colours are directed onto your projector screen all at once. The way a DLP projector operates is totally different and even the produced image appears is not the same. With DLP, white light from the lamp is directed through a rotating 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 as described above reflect the coloured light on the pixels to produce the image elements. The elements of the image are cast in sequence on the screen, one colour at a time. The viewer’s eyes will then put together each coloured element of the image into the single complete image. Using LCD projectors, all colours are available all the time to offer the best brightness and superb colour accuracy. In DLP, just one colour is available at a time, and so resulting in lower colour brightness and accuracy. Some designers have put a white segment in the colour wheel to improve brightness overall, but this also degrades colour accuracy.

I see 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 projector is capable of producing. DLP projectors do possess high contrast specifications in comparison to a majority of LCD projectors. At one glance, this appears to be a benefit, however, in truth, the true black level is determined by the ambient light in the room where the projector is being used. Do not be duped by contrast specifications on websites and in brochures.

When the content you are trying to project requires moving images, DLP projection technology can also have image errors, or ‘artifacts’. The most typical 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 position between the time red, blue and green colours are projected. LCD projectors do not have this disadvantage because the colours are sent at once. DLP builders have created 3DLP solutions using 3 chips to resolve the colour break up artifacts, but the expense of these projectors make them impractical for many businesses and consumers.

Another 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 how the different colours of light refract differing amounts when directed through the same lens. The problem with DLP projectors is that they utilise the one same panel with 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, some extra yellow colour will come up above and a spill of blue will appear below something as simple as a single black line. While being built LCD projectors can be set to reduce these effects on the projected image, as each colour is projected on its own LCD panels.

The sole true advantage (excluding price) with going with a DLP projector is its smaller total size and weight. However, this is only relevant in regard to portability and has to be traded off against the image superiority of LCD projectors. If the outcome of the picture quality is important to you, then the solution is no-brainer. Choose an LCD projector! LCD projectors will constantly create bright, colourful images with fewer image errors. If you want to know more about LCD technology in more detail, have a look at this tremendous resource website: Explore 3LCD. If you have any more questions, jump onto Projector Central and send me an email.

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