Projectors: LCD Verses DLP (The downfall of DLP technology)
The most typical question customers ask when purchasing a new projector for the home, office, or classroom is: should I purchase an LCD projector or a DLP projector? LCD, standing for ‘liquid crystal device’ and DLP, an acronym for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many different brands and models available, it can be difficult for consumers to make a choice between these technologies. Ultimately LCD projectors provide superior image quality and colour accuracy. The next paragraph will explain why DLP projectors struggle with projecting an equal grade of image quality.
Think of a set of blinds in your room over your bedroom window. With the twist of a rod you can make the shutters open or closed, depending on if you want to let light in or not. Such is exactly how an LCD projector behaves. Each pixel operates like a single shutter on a set of blinds to either send 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 works to either reflect light or block it.
How the light source is processed from the point at which the projector switches on to when the image reaches your screen is vitally significant for image quality, brightness and colour accuracy. LCD projectors direct white light from the lamp by splitting it into red, blue and green components, by three mirrors which direct the coloured light to 3 individual LCD panels. The 3 LCD panels make the elements of the image by turning each pixel on and off. The pixels are then simultaneously processed in a glass prism to form the projector image. Something important to understad about LCD projectors is that all three colours are delivered onto your projector screen at once. The way a DLP projector works is totally different and even the produced image appears is not the same. With DLP, white light from the lamp is sent through a spinning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This method of forming an image creates a sequence of red, blue and green light. The millions of micro mirrors as mentioned above reflect the coloured light on the pixels to construct the image elements. The elements of the image are displayed in sequence on the screen, one colour at a time. The viewer’s eyes will then draw each coloured element of the image into the single whole image. From LCD projectors, all colours are available all the time to offer the best brightness and fantastic colour accuracy. In DLP, just one colour is available at any given time, and so causing lower colour brightness and accuracy. Some DLP designers have put a white segment for the colour wheel to improve all over brightness, but this goes and lessens colour accuracy.
I find in forums all the time that DLP has a higher contrast ratio and thus must be better. 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 technology is capable of producing. DLP projectors do provide high contrast specifications in comparison to a majority of LCD projectors. At a glance, this must be an advantage, however, in truth, the true black level is determined by the ambient light in the room where the projector is utilised. Do not be tricked by contrast specifications on websites and in brochures.
When the content you want to project includes moving images, DLP projection technology also creates image marks, or ‘artifacts’. The most often seen artifact that a DLP projector displays with moving images is colour break up. Colour break up is incontrovertible in DLP systems because moving images change up between the time red, blue and green colours are projected. LCD projectors do not have this disadvantage because every colour is projected with the others. DLP manufacturers have developed 3DLP solutions using 3 chips to fix the colour break up problem, but the price tag of these projectors make them impractical for many businesses and consumers.
Another differentiation between LCD and DLP is how they match the balance for the refractive qualities of light. Jump back to high school science, and they taught you how the different colours of light refract various amounts when shone through the same lens. The downside with DLP projectors is that they have the one same panel for the same lens to project Red, Blue and Green. All 3 colours are obviously not the same and refract light differently. Generally with a DLP projector, an extra yellow colour will appear above and some extra blue will be projected below an image of something as simple as a lone black line. In manufacturing LCD projectors can be fixed to take away these effects on the projected image, because each colour is directed on a separate LCD panels.
The only true buy point (excluding price) with choosing a DLP projector is its smaller size and weight. However, this is only relevant to mobility and has to be traded off against the image plusses of LCD projectors. If the result of the picture quality is vital to you, then the decision is a no-brainer. Choose an LCD projector! LCD projectors will always create bright, colourful images with fewer image imperfections. If you want to find out more about LCD technology in more detail, have a look at this spectacular 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 at Projector Central, Australia’s top 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.
Sphere: Related ContentComments
Tell me what you're thinking...
and oh, if you want a pic to show with your comment, go get a gravatar!