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The most common question customers ask when acquiring a new projector for the home, office, or classroom is: would I buy an LCD projector or a DLP projector? LCD, short for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two most common projector imaging technologies. With so many brands and models available, it can be overwhelming for the buyer to pick between these technologies. The simple fact of the matter is that LCD projectors provide far better image quality and colour accuracy. The article below tells you why DLP projectors struggle with projecting an equal level of image quality.

Imagine a set of blinds in your household for your bedroom window. By twisting a rod you can turn the shutters open or closed, depending on if you want to let light in or not. That is exactly how an LCD projector behaves. 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 created 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 switched on to when the image reaches your screen is extremely significant with regard to image quality, brightness and colour accuracy. LCD projectors direct white light from the lamp by dividing it into red, blue and green components, by three mirrors which direct the coloured light to 3 different LCD panels. The 3 LCD panels make the elements of the image by shining each pixel on and off. The pixels are then combined in a glass prism to deliver the projector image. A point to realise about LCD projectors is that all three colours are sent onto your wall at the same time. The way a DLP projector operates is very different and even the produced image appears is not the same. With DLP, white light from the lamp is processed through a rotating colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of projecting 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 create the image elements. The elements of the image are cast in sequence on the screen, one colour at a time. The viewer’s vision will then combine each coloured element of the image into the single full image. Using LCD projectors, all colours are available all the time to form the best brightness and fantastic colour accuracy. In DLP, just one colour is available at any given time, and so causing lower colour brightness and accuracy. Some DLP designers have included a white segment for the colour wheel to improve all over brightness, but this also detracts from colour accuracy.

I read in forums all the time that DLP offers a higher contrast ratio and thus must be better quality. For those who do not 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. DLP projectors do have high contrast specifications in comparison to a majority of LCD projectors. At one glance, this can seem to be an advantage, however, in reality, the true black level is determined by the ambient light in the room where the projector is in use. Do not be duped by contrast specifications on websites and in brochures.

When the content you want to view has moving images, DLP projection technology can also create image imperfections, 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 keep changing between the time red, blue and green colours are shone. LCD projectors do not have this disadvantage because all the colours are sent simultaneously. DLP developers have come up with 3DLP solutions using 3 chips to solve the colour break up issue, but the expense of these projectors make them hardly practical for the majority of businesses and consumers.

Another variance between LCD and DLP is how they balance for the refractive qualities of light. Jump back to high school science, and remember how the various colours of light refract various amounts when projected through the same lens. The downside with DLP projectors is that they use 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 at different levels. Generally with a DLP projector, some yellow colour will come up above and an extra blue will come up below an image as simple as a single black line. During manufacturing LCD projectors can be adapted to reduce these effects on the projected image, as each colour is refracted on separate LCD panels.

The only real advantage (excluding price) with picking a DLP projector is its smaller size and weight. However, this is only relevant in regard to transport and cannot be traded off against the image benefits of LCD projectors. If the result of the picture quality is important to you, then the decision is simple. Take an LCD projector! LCD projectors will always produce bright, colourful images with fewer image imperfections. If you want to learn more about LCD technology in more detail, check out this spectacular 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 for Projector Central, Australia’s top online retailer for projectors. Brisbane based, Projector Central has served Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.