The most common question customers ask when acquiring a new projector for the home, office, or classroom is: do I purchase an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, standing for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many different brands and types available, it can be difficult for the buyer to make a decision between those technologies. It comes down to the fact that LCD projectors give better image quality and colour accuracy. The article below will explain why DLP projectors struggle with bringing up an equal grade of image quality.

Imagine a set of blinds in your house over your bedroom window. By pulling a rod you can make the shutters open or closed, according to whether you want to let light in or not. Such is exactly how an LCD projector functions. Each pixel works like its own 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 experts 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 switched on to when the image reaches your screen is vitally important for 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 transfer the coloured light to 3 individual LCD panels. The 3 LCD panels form the elements of the image by shining each pixel on and off. The pixels are then projected in a glass prism to send the projector image. Something to remember about LCD projectors is that all three colours are directed onto your screen at the same time. The way a DLP projector functions is very different and even the produced image looks 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 method of creating an image casts a sequence of red, blue and green light. The millions of micro mirrors described above reflect the coloured light on the pixels to create the image elements. The elements of the image are projected 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 offer the highest brightness and superb colour accuracy. In DLP, just one colour is available at once, and so causing lower colour brightness and accuracy. Some DLP manufacturers have placed a white segment in the colour wheel to improve general brightness, but this also degrades colour accuracy.

I read in forums all the time that DLP offers a higher contrast ratio and as such must be superior. For those who do not 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 projector is capable of. DLP projectors do have high contrast specifications in comparison to many LCD projectors. At one glance, this appears to be a benefit, 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 are trying to see includes moving images, DLP projection technology also has image imperfections, 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 keep changing between the time red, blue and green colours are shone. LCD projectors do not have this problem because all the colours are projected at the same time. DLP builders have formed 3DLP solutions using 3 chips to resolve the colour break up issue, but the price tag of these projectors make them impractical 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. Think back to high school science, and remember how the different colours of light refract varied amounts when passing through the same lens. The downside with DLP projectors is that they have the one same panel and the same lens to project Red, Blue and Green. All 3 colours are different and refract light in a different way. Most of the time with a DLP projector, some yellow colour will come up above and a superfluous blue will show below an image as simple as a lone black line. In manufacturing LCD projectors can be fixed to minimize these effects on the projected image, because each colour is processed on a separate LCD panels.

The sole veritable advantage (excluding price) with going with a DLP projector is its smaller total size and weight. However, this is only relevant for mobility and must be traded off against the image advantages of LCD projectors. If the result of the picture quality is vital to you, then the solution is a no-brainer. Choose an LCD projector! LCD projectors will always create bright, colourful images with fewer image imperfections. If you need to find out more about LCD technology in more detail, check out this fabulous resource website: Explore 3LCD. If you have any other questions, jump onto Projector Central and send me an email.

Jonathan King is the sales and marketing manager with Projector Central, Australia’s premier online provider 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.