Blackhat SEO Blog

The most common question that is asked when acquiring a new projector for the home, office, or classroom is: will I buy an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, standing for ‘digital light processing’ are the two most popular projector imaging technologies. With so many different brands and different models available, it can be overwhelming for clients to pick between these technologies. Ultimately LCD projectors provide far better image quality and colour accuracy. The next paragraph will explain why DLP projectors struggle with projecting the same rate of image quality.

Visualise a set of blinds in your home over your bedroom window. By twisting a rod you can have 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 operates like its own shutter on a set of blinds to either allow 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 functions to either reflect light or block it.

How the light source is processed from the time the projector switches on to when the picture reaches your screen is vitally significant in regard to image quality, brightness and colour accuracy. LCD projectors process white light from the lamp by separating it into red, blue and green components, by three mirrors which project the coloured light to 3 different LCD panels. The 3 LCD panels form the elements of the image by processing each pixel on and off. The pixels are then meshed in a glass prism to deliver the projector image. Something to realise about LCD projectors is that all three colours are projected onto your screen at the same time. The way a DLP projector runs is totally different and even the produced image comes out is not the same. With DLP, white light from the lamp is directed through a rotating colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This way of forming an image requires a sequence of red, blue and green light. The millions of micro mirrors as mentioned above reflect the coloured light on the pixels to create 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 a single complete image. From LCD projectors, all colours are available all the time to form high brightness and great colour accuracy. In DLP, only one colour is available at any given time, causing lower colour brightness and accuracy. Some DLP developers have added a white segment for the colour wheel to improve all over brightness, but this further detracts from colour accuracy.

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

When the content you wish to bring to life requires moving images, DLP projection technology also has image imperfections, or ‘artifacts’. The most commonplace artifact that a DLP projector displays with moving images is colour break up. Colour break up is unavoidable in DLP systems because moving images change up between the time red, blue and green colours are pulled up. LCD projectors do not have this problem because all colours are delivered at the same time. DLP manufacturers have come up with 3DLP solutions using 3 chips to resolve the colour break up artifacts, but the price of these projectors make them almost impossible for the majority of businesses and consumers.

Another differentiation between LCD and DLP is how they match the balance for the refractive qualities of light. Take yourself back to high school science, and recall how the various colours of light refract varied amounts when directed through the same lens. The downfall 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 at different levels. Generally with a DLP projector, some yellow colour will appear above and a spill of blue will show below an image as simple as a straight black line. In building LCD projectors can be adjusted to take away these effects on the projected image, as each colour is directed on its own LCD panels.

The sole actual buy point (excluding price) with going with a DLP projector is its overall smaller size and weight. However, this is only relevant with regard to transporting the device and cannot be traded off against the image superiority of LCD projectors. If overall picture quality is important to you, then the answer is simple. Go for an LCD projector! LCD projectors will constantly show bright, colourful images with fewer image mistakes. If you need to learn more about LCD technology in more detail, have a gander at this spectacular resource website: Explore 3LCD. If you have any further questions, go to Projector Central and send me an email.

Jonathan King is the sales and marketing manager at 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.

This entry was posted on Monday, July 19th, 2010 at 1:35 pm and is filed under Uncategorized.