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The typical question asked when buying a new projector for the home, office, or classroom is: would I buy an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two top projector imaging technologies. With so many company brands and types available, it can be challenging for clients to choose between those technologies. The fact is that LCD projectors offer far superior image quality and colour accuracy. The next part of this article will explain why DLP projectors struggle with bringing up the same grade of image quality.

It’s like a set of blinds in your house over your bedroom window. By pulling on a rod you can make the shutters open or closed, according to whether you want to let light in or not. This is exactly how an LCD projector operates. Each pixel operates like a single shutter on a set of blinds to either shine light through or to block it. DLP on the other hand is made up 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 image reaches your screen is vitally significant to image quality, brightness and colour accuracy. LCD projectors project 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 processing each pixel on and off. The pixels are then simultaneously processed in a glass prism to deliver the projector image. A significant point to remember about LCD projectors is that all three colours are directed onto your projected surface simultaneously. The way a DLP projector works is totally different and even the final product of how an image comes out 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 approach to projecting an image casts a sequence of red, blue and green light. The millions of micro mirrors 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 eyes will then put together each coloured element of the image into a whole image. From LCD projectors, all colours are available all the time to form the best brightness and superb colour accuracy. In DLP, only one colour is available at a time, and so resulting in lower colour brightness and accuracy. Some DLP manufacturers have put a white segment for the colour wheel to improve general brightness, but this then detracts from colour accuracy.

I read in forums all the time that DLP has a higher contrast ratio and as such 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 machine is able to produce. DLP projectors do provide high contrast specifications when compared to many 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 while the projector is in use. Do not be fooled by contrast specifications on websites and in brochures.

When the content you are trying to view needs moving images, DLP projection technology also creates image marks, or ‘artifacts’. The most common artifact that a DLP projector displays with moving images is colour break up. Colour break up is inherent in DLP systems because moving images change between the time red, blue and green colours are shone. LCD projectors do not have this disadvantage because the colours are delivered simultaneously. DLP developers have created 3DLP solutions using 3 chips to fix the colour break up issue, but the expense of these projectors make them hardly practical for the majority of businesses and consumers.

Another differentiation between LCD and DLP is how they make up for the refractive qualities of light. Jump back to high school science, and remember when they taught you how the various colours of light refract various amounts when projected through the same lens. The downfall 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 different and refract light at different levels. Usually with a DLP projector, a superfluous yellow colour will come up above and an extra blue will come through below something as simple as a single black line. While being built LCD projectors can be adjusted to reduce these effects on the projected image, as each colour is processed on isolated LCD panels.

The only actual buy point (excluding price) with deciding on a DLP projector is its smaller size and weight. However, this is only relevant in regard to mobility and cannot be traded off against the image superiority of LCD projectors. If the outcome of the picture quality is crucial to you, then the choice is a no-brainer. Choose an LCD projector! LCD projectors will always show bright, colourful images with fewer image mistakes. If you need to find out more about LCD technology in more detail, have a look at this tremendous resource website: Explore 3LCD. If you have any other questions, go to Projector Central and send me an email.

Jonathan King is the sales and marketing manager of Projector Central, Australia’s number one online store 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.

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