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The most typical question customers ask when purchasing a new projector for the home, office, or classroom is: should I take an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, an acronym for ‘digital light processing’ are the two most common projector imaging technologies. With so many brands and models available, it can be confusing for consumers to make a decision between the two technologies. Ultimately LCD projectors offer superior image quality and colour accuracy. The following article explains why DLP projectors struggle with projecting the same standard of image quality.

It’s like a set of blinds in your house for your bedroom window. By pulling on a rod you can make the shutters open or closed, depending on whether you want to let light in or not. And this is exactly how an LCD projector functions. Each pixel functions like a unique shutter on a set of blinds to either pass light through or to block it. DLP on the other hand is constructed of millions of microscopic mirrors or ‘pixel elements’ as professionals 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 turns on to when the picture reaches your screen is absolutely important in regard to 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 send the coloured light to 3 different 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 create the projector image. Something important to remember about LCD projectors is that all three colours are directed onto your projector screen at once. The way a DLP projector runs is very different and even the way an image looks is not the same. With DLP, white light from the lamp is directed 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 casts a sequence of red, blue and green light. The millions of micro mirrors as described above reflect the coloured light on the pixels to create the image elements. The elements of the image are sent 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 whole image. In LCD projectors, all colours are available all the time to create the top level of brightness and fantastic colour accuracy. In DLP, only one colour is available at once, and so resulting in lower colour brightness and accuracy. Some DLP designers have added a white segment in the colour wheel to improve overall brightness, but this further degrades colour accuracy.

I find in forums all the time that DLP gives a higher contrast ratio and therefore must be superior quality. For those 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 machine is capable of producing. DLP projectors do offer high contrast specifications as compared to a majority of LCD projectors. Initially, this must be an advantage, however, in real life, the true black level is determined by the ambient light in the room while the projector is being utilised. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you want to bring to life has moving images, DLP projection technology can also have image imperfections, or ‘artifacts’. The most common 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 up between the time red, blue and green colours are projected. LCD projectors do not have this downside because the colours are delivered at once. DLP manufacturers have formed 3DLP solutions using 3 chips to solve the colour break up error, but the expense of these projectors make them not practical for many businesses and consumers.

Another differentiation between LCD and DLP is how they match the balance for the refractive qualities of light. Think back to high school science, and recall when they taught you how various colours of light refract varied amounts when passing through the same lens. The problem with DLP projectors is that they have the one same panel with the same lens to project Red, Blue and Green. All 3 colours are different and refract light in a different way. Generally with a DLP projector, a spill of yellow colour will come up above and an extra blue will appear below an image containing something as simple as a single black line. While being built LCD projectors can be adapted to take away these effects on the projected image, as each colour is directed on a separate LCD panels.

The isolated true advantage (excluding price) with deciding on a DLP projector is its smaller size and weight. However, this is only relevant in regard to transporting the device and cannot be traded off against the image benefits of LCD projectors. If resulting picture quality is vital to you, then the decision is no-brainer. Take an LCD projector! LCD projectors will consistently show bright, colourful images with fewer image mistakes. If you wish to learn more about LCD technology in more detail, check out this fantastic 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 at Projector Central, Australia’s number one online store 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.