The most common question customers ask when purchasing a new projector for the home, office, or classroom is: do I purchase 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 most popular projector imaging technologies. With so many business brands and models available, it can be difficult for clients to make a decision between the two technologies. It comes down to the fact that LCD projectors have superior image quality and colour accuracy. The next paragraph explains why DLP projectors struggle with bringing up an equal standard of image quality.

Imagine a set of blinds in your room for 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. That is exactly how an LCD projector works. Each pixel operates like a single shutter on a set of blinds to either shine 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 works to either reflect light or block it.

How the light source is processed from when the projector turns on to when the picture reaches your screen is extremely important with 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 transfer the coloured light to 3 separate LCD panels. The 3 LCD panels make the elements of the image by switching each pixel on and off. The pixels are then combined in a glass prism to create the projector image. Something important to know about LCD projectors is that all three colours are sent onto your screen all at the same time. The way a DLP projector operates is very different and even the way an image comes out is not the same. With DLP, white light from the lamp is projected through a rotating colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of making 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 form 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 draw each coloured element of the image into the single full image. Using LCD projectors, all colours are available all the time to create high 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 DLP developers have added a white segment into the colour wheel to improve brightness overall, but this also damages colour accuracy.

I hear in forums all the time that DLP has a higher contrast ratio and ergo must be superior. For those unaware, 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 offer high contrast specifications compared to the majority of LCD projectors. At one glance, this must be an advantage, however, in reality, the true black level is determined by the ambient light in the room where the projector is utilised. Do not be duped by contrast specifications on websites and in brochures.

When the content you want to view requires moving images, DLP projection technology also creates image marks, or ‘artifacts’. The most commonplace artifact that a DLP projector creates with moving images is colour break up. Colour break up is to be expected in DLP systems because moving images change between the time red, blue and green colours are displayed. LCD projectors do not have this characteristic because every colour is sent simultaneously. DLP designers have created 3DLP solutions using 3 chips to answer the colour break up issue, but the expense of these projectors make them impractical for most businesses and consumers.

Another variance between LCD and DLP is how they compensate for the refractive qualities of light. Remember back to high school science, and recall how different colours of light refract different amounts when passing through the same lens. The downside with DLP projectors is that they take the one same panel with the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light differently. Generally with a DLP projector, an extra yellow colour will come through above and a superfluous blue will come through below an image as simple as a single black line. During manufacturing LCD projectors can be adapted to take away these effects on the projected image, because each colour is processed on its own LCD panels.

The one true plus (excluding price) with buying a DLP projector is its smaller size and weight. However, this is only relevant to transporting the device and needs to be traded off against the image plusses of LCD projectors. If overall picture quality is crucial to you, then the answer is a no-brainer. Take an LCD projector! LCD projectors will constantly produce bright, colourful images with fewer image imperfections. If you want to learn more about LCD technology in more detail, have a gander at this spectacular resource website: Explore 3LCD. If you have any persisting questions, get onto Projector Central and send me an email.

Jonathan King is the sales and marketing manager for Projector Central, Australia’s top online provider for projectors. Brisbane-based, Projector Central has serviced Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.

Sphere: Related Content