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The most common question that is asked when buying 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 most popular projector imaging technologies. With so many business brands and types available, it can be difficult for clients to make a decision between these technologies. The fact is that LCD projectors give far superior image quality and colour accuracy. The following article will tell you why DLP projectors struggle with creating the same grade of image quality.

Think of a set of blinds in your household covering your bedroom window. By pulling a rod you can have the shutters open or closed, according to if you want to let light in or not. Such is exactly how an LCD projector operates. Each pixel works like an individual shutter on a set of blinds to either pass light through or to block it. DLP on the other hand is formed 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 when the projector turns on to when the content 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 stand alone LCD panels. The 3 LCD panels make the elements of the image by switching each pixel on and off. The pixels are then simultaneously processed in a glass prism to form the projector image. A point to know about LCD projectors is that all three colours are projected onto your wall all at the same time. The way a DLP projector works is widely different and even how an image shows up is not the same. With DLP, white light from the lamp is sent 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 requires 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 projected in sequence on the screen, one colour at a time. The viewer’s vision will then put together each coloured element of the image into the full image. Using LCD projectors, all colours are available all the time to create the best brightness and spectacular colour accuracy. In DLP, only one colour is available at any given time, and so resulting in lower colour brightness and accuracy. Some developers have put a white segment for the colour wheel to improve general brightness, but this further lessens colour accuracy.

I hear in forums all the time that DLP gives a higher contrast ratio and therefore must be better. 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 projector is able to produce. DLP projectors do provide high contrast specifications in comparison to the majority of LCD projectors. At one glance, this must be a plus, however, in reality, the true black level is determined by the ambient light in the room while the projector is being utilised. Do not be duped by contrast specifications on websites and in brochures.

When the content you are trying to project requires moving images, DLP projection technology also has image errors, or ‘artifacts’. The most commonplace artifact that a DLP projector forms 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 downside because all the colours are sent with the others. DLP builders have come up with 3DLP solutions using 3 chips to solve the colour break up error, but the price tag of these projectors make them almost impossible for the majority of businesses and consumers.

Another difference between LCD and DLP is how they make up for the refractive qualities of light. Take yourself back to high school science, and recall when they taught you how various colours of light refract differing amounts when projected through the same lens. The problem with DLP projectors is that they take 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. Usually with a DLP projector, some extra yellow colour will show above and some blue will be projected below an image as simple as a straight black line. During manufacturing LCD projectors can be adjusted to reduce these effects on the projected image, as each colour is processed on a separate LCD panels.

The one true benefit (excluding price) with picking a DLP projector is its overall smaller size and weight. However, this is only relevant to mobility and needs to be traded off against the image plusses of LCD projectors. If the outcome of the picture quality is important to you, then the choice is easy. Go for an LCD projector! LCD projectors will constantly create bright, colourful images with fewer image mistakes. If you need to learn more about LCD technology in more detail, check out this tremendous resource website: Explore 3LCD. If you have any additional questions, visit Projector Central and send me an email.

Jonathan King is the sales and marketing manager for Projector Central, Australia’s leading online shop for projectors. Based in Brisbane, Projector Central has been serving Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.