The most common question heard when acquiring a new projector for the home, office, or classroom is: would I purchase an LCD projector or a DLP projector? LCD, standing for ‘liquid crystal device’ and DLP, standing for ‘digital light processing’ are the two most common projector imaging technologies. With so many brands and different models available, it can be challenging for the buyer to decide between both technologies. It comes down to the fact that LCD projectors offer far superior image quality and colour accuracy. The article below explains why DLP projectors struggle with creating a comparable rate of image quality.
Think of a set of blinds in your home on your bedroom window. By a twist of a rod you can turn the shutters open or closed, according to whether you want to let light in or not. And that is exactly how an LCD projector functions. Each pixel works like a single shutter on a set of blinds to either allow light through or to block it. DLP on the other hand is created of millions of microscopic mirrors or ‘pixel elements’ as experts 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 turns on to when the content reaches your screen is ultimately significant in regard to 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 direct the coloured light to 3 separate 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 create the projector image. Something to know about LCD projectors is that all three colours are sent onto your wall simultaneously. The way a DLP projector works is vastly different and even how an 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 way of forming an image requires a sequence of red, blue and green light. The millions of micro mirrors as mentioned 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 combine each coloured element of the image into a single complete image. From LCD projectors, all colours are available all the time to create high brightness and spectacular colour accuracy. In DLP, just one colour is available at any given time, and so resulting in lower colour brightness and accuracy. Some DLP developers have placed a white segment for the colour wheel to improve brightness overall, but this goes and degrades colour accuracy.
I hear in forums all the time that DLP gives a higher contrast ratio and as such must be superior. For those who are uncertain, 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 system is capable of. DLP projectors do have high contrast specifications as compared to most LCD projectors. Initially, this appears to be a plus, however, in real life, the true black level is determined by the ambient light in the room where the projector is used. Do not be tricked by contrast specifications on websites and in brochures.
When the content you wish to bring to life has moving images, DLP projection technology can also create image marks, or ‘artifacts’. The most typical 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 position between the time red, blue and green colours are shone. LCD projectors do not have this disadvantage because every colour is sent with the others. DLP designers have formed 3DLP solutions using 3 chips to fix the colour break up issue, but the price tag of these projectors make them hardly practical for the large part of businesses and consumers.
Another point of difference between LCD and DLP is how they balance for the refractive qualities of light. Take yourself back to high school science, and remember when they taught you how various colours of light refract various amounts when projected through the same lens. The disadvantage with DLP projectors is that they take the one same panel for the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light in different ways. Usually with a DLP projector, some yellow colour will appear above and some blue will come through below an image of something as simple as a lone black line. In building LCD projectors can be adapted to minimize these effects on the projected image, because each colour is processed on separate LCD panels.
The isolated veritable plus (excluding price) with picking a DLP projector is its overall smaller size and weight. However, this is only relevant to mobility and must be traded off against the image superiority of LCD projectors. If the result of the picture quality is vital to you, then the decision is a no-brainer. Go with an LCD projector! LCD projectors will always create bright, colourful images with fewer image mistakes. If you desire to learn more about LCD technology in more detail, have a gander at this tremendous resource website: Explore 3LCD. If you have any further questions, go to Projector Central and send me an email.
Jonathan King is the sales and marketing manager for Projector Central, Australia’s top online store for projectors. Based in Brisbane, Projector Central has served Australia for 15 years. For data projectors in the Gold Coast and Interactive Whiteboards, contact Projector Central today.
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