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The most typical question that is asked when acquiring a new projector for the home, office, or classroom is: should I buy an LCD projector or a DLP projector? LCD, standing for ‘liquid crystal device’ and DLP, an acronym for ‘digital light processing’ are the two top projector imaging technologies. With so many brands and different types available, it can be overwhelming for clients to make a decision between those technologies. Ultimately LCD projectors offer far superior image quality and colour accuracy. The article below will explain why DLP projectors struggle with bringing up the same standard of image quality.

Visualise a set of blinds in your room on your bedroom window. By a twist of a rod you can have the shutters open or closed, depending on if you want to let light in or not. And that is exactly how an LCD projector works. Each pixel operates like an individual shutter on a set of blinds to either shine light through or to block it. DLP on the other hand is constructed of millions of microscopic mirrors or ‘pixel elements’ as the professionals like to call them. Each pixel element works to either reflect light or block it.

How the light source is processed from when the projector is turned on to when the picture reaches your screen is vitally important in regard to image quality, brightness and colour accuracy. LCD projectors project white light from the lamp by dividing it into red, blue and green components, by three mirrors which project the coloured light to 3 separate LCD panels. The 3 LCD panels cast the elements of the image by turning each pixel on and off. The pixels are then combined in a glass prism to create the projector image. A significant point to realise about LCD projectors is that all three colours are projected onto your screen all at once. The way a DLP projector runs is vastly different and even the produced image shows up 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 approach to creating 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 sent in sequence on the screen, one colour at a time. The viewer’s eye will then draw each coloured element of the image into the single complete image. From LCD projectors, all colours are available all the time to form high brightness and spectacular colour accuracy. In DLP, just one colour is available at a time, resulting in lower colour brightness and accuracy. Some DLP developers have included a white segment for the colour wheel to improve brightness overall, but this also damages colour accuracy.

I find in forums all the time that DLP offers a higher contrast ratio and thus must be better quality. 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 projector is capable of. DLP projectors do possess high contrast specifications as compared to a majority of LCD projectors. At a glance, this must be a plus, however, in reality, the true black level is determined by the ambient light in the room while the projector is utilised. 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 can also create image imperfections, or ‘artifacts’. The most common 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 problem because all the colours are delivered with the others. DLP manufacturers have formed 3DLP solutions using 3 chips to solve the colour break up problem, but the price 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. Jump back to high school science, and remember when they taught you how the various colours of light refract varied amounts when directed through the same lens. The problem 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 different and refract light in a different way. Most of the time with a DLP projector, a superfluous yellow colour will show above and a spill of blue will come up below something as simple as a straight black line. In manufacturing LCD projectors can be adjusted to minimize these effects on the projected image, as each colour is directed on isolated LCD panels.

The one true advantage (excluding price) with choosing a DLP projector is its smaller total size and weight. However, this is only relevant to transporting the device and has to be traded off against the image advantages of LCD projectors. If overall picture quality is crucial to you, then the solution is no-brainer. Go for an LCD projector! LCD projectors will definitely show bright, colourful images with fewer image mistakes. If you wish to know more about LCD technology in more detail, have a gander at this spectacular resource website: Explore 3LCD. If you have any additional questions, visit Projector Central and send me an email.

Jonathan King is the sales and marketing manager of Projector Central, Australia’s leading online store for projectors. Brisbane-based, Projector Central has been servicing Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.