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The common question customers ask when looking for a new projector for the home, office, or classroom is: do I get an LCD projector or a DLP projector? LCD, short for ‘liquid crystal device’ and DLP, which stands for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many different brands and different models available, it can be overwhelming for the buyer to choose between these technologies. Ultimately LCD projectors offer far superior image quality and colour accuracy. The following article will tell you why DLP projectors struggle with projecting a comparable grade of image quality.

Think of a set of blinds in your home over your bedroom window. By pulling on a rod you can make the shutters open or closed, depending on if you want to let light in or not. And such is exactly how an LCD projector works. Each pixel works like a unique shutter on a set of blinds to either send light through or to block it. DLP on the other hand is formed 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 at which the projector is turned on to when the image reaches your screen is absolutely significant 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 individual LCD panels. The 3 LCD panels cast the elements of the image by switching each pixel on and off. The pixels are then projected in a glass prism to send the projector image. Something to know about LCD projectors is that all three colours are delivered onto your projector screen all at the same time. The way a DLP projector functions is vastly different and even 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 creating an image forms a sequence of red, blue and green light. The millions of micro mirrors as mentioned above reflect the coloured light on the pixels to construct the image elements. The elements of the image are sent in sequence on the screen, one colour at a time. The viewer’s eyes will then draw each coloured element of the image into the total image. From LCD projectors, all colours are available all the time to deliver the top level of brightness and great colour accuracy. In DLP, just one colour is available at any given time, and so resulting in lower colour brightness and accuracy. Some designers have placed a white segment into the colour wheel to improve all over brightness, but this also degrades colour accuracy.

I see in forums all the time that DLP has a higher contrast ratio and thus must be superior quality. 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 machine is capable of producing. DLP projectors do offer high contrast specifications as compared to most LCD projectors. At one glance, this can seem to be a benefit, however, in truth, the true black level is determined by the ambient light in the room when the projector is in use. Do not be tricked by contrast specifications on websites and in brochures.

When the content you plan to see requires moving images, DLP projection technology can also have image marks, or ‘artifacts’. The most often seen artifact that a DLP projector creates with moving images is colour break up. Colour break up is unavoidable in DLP systems because moving images change position between the time red, blue and green colours are displayed. LCD projectors do not have this problem because the colours are processed simultaneously. DLP manufacturers have developed 3DLP solutions using 3 chips to answer the colour break up artifacts, but the cost of these projectors make them not 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. Remember back to high school science, and remember how the various colours of light refract differing amounts when projected through the same lens. The downside with DLP projectors is that they utilise the one same panel and the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light in different ways. Most of the time with a DLP projector, a spill of yellow colour will come up above and some blue will show below something as simple as a lone black line. In building LCD projectors can be set to take away these effects on the projected image, as each colour is refracted on separate LCD panels.

The sole real plus (excluding price) with choosing a DLP projector is its smaller overall size and weight. However, this is only relevant with regard to mobility and cannot be traded off against the image benefits of LCD projectors. If the result of the picture quality is vital to you, then the solution is easy. Choose an LCD projector! LCD projectors will always make bright, colourful images with fewer image imperfections. If you desire to ask more about LCD technology in more detail, see this fabulous resource website: Explore 3LCD. If you have any other questions, visit Projector Central and send me an email.

Jonathan King is the sales and marketing manager with Projector Central, Australia’s number one online shop for projectors. Brisbane based, 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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