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The common question that is asked when purchasing a new projector for the home, office, or classroom is: would I buy an LCD projector or a DLP projector? LCD, an acronym for ‘liquid crystal device’ and DLP, an acronym for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many business brands and models available, it can be confusing for the buyer to decide between both technologies. It comes down to the fact that LCD projectors provide better image quality and colour accuracy. The following article tells you why DLP projectors struggle with projecting a similar rate of image quality.

It’s like a set of blinds in your room on your bedroom window. By pulling a rod you can have the shutters open or closed, according to whether you want to let light in or not. And such is exactly how an LCD projector operates. Each pixel functions like a unique shutter on a set of blinds to either send light through or to block it. DLP on the other hand is created 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 the point when the projector switches on to when the image reaches your screen is extremely important with regard to image quality, brightness and colour accuracy. LCD projectors shine 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 cast the elements of the image by shining each pixel on and off. The pixels are then meshed in a glass prism to deliver the projector image. Something important to understad about LCD projectors is that all three colours are directed onto your screen all at the same time. The way a DLP projector functions is totally different and even the way an image appears is not the same. With DLP, white light from the lamp is processed through a turning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of making an image forms a sequence of red, blue and green light. The millions of micro mirrors described 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 pull together each coloured element of the image into a full image. With 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 any given time, and so resulting in lower colour brightness and accuracy. Some designers have placed a white segment for the colour wheel to improve all over brightness, but this goes and lessens colour accuracy.

I read in forums all the time that DLP provides a higher contrast ratio and as such must be superior. For those who are 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 technology is capable of. DLP projectors do have high contrast specifications compared to most LCD projectors. At first glance, this must be a benefit, however, in reality, the true black level is determined by the ambient light in the room where the projector is being utilised. Do not be fooled by contrast specifications on websites and in brochures.

When the content you want to view includes moving images, DLP projection technology also creates 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 keep changing between the time red, blue and green colours are shone. LCD projectors do not have this disadvantage because all the colours are projected at once. DLP designers have formed 3DLP solutions using 3 chips to answer the colour break up error, but the price of these projectors make them impractical for many businesses and consumers.

Another 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 the various colours of light refract varied amounts when shone through the same lens. The disadvantage with DLP projectors is that they use the one same panel with the same lens to project Red, Blue and Green. All 3 colours are not the same and refract light at different levels. Most of the time with a DLP projector, some yellow colour will be projected above and an extra blue will come up below something as simple as a single black line. While being built LCD projectors can be adjusted to minimize these effects on the projected image, because each colour is projected on a separate LCD panels.

The one actual advantage (excluding price) with going with a DLP projector is its overall smaller size and weight. However, this is only relevant to transporting the device and cannot be traded off against the image plusses of LCD projectors. If the outcome of the picture quality is important to you, then the answer is easy. Go for an LCD projector! LCD projectors will constantly produce bright, colourful images with fewer image errors. If you desire to know more about LCD technology in more detail, have a gander at this tremendous resource website: Explore 3LCD. If you have any further questions, get onto Projector Central and send me an email.

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