The typical question customers ask when buying a new projector for the home, office, or classroom is: will I purchase an LCD projector or a DLP projector? LCD, short for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two most common projector imaging technologies. With so many company brands and different types available, it can be difficult for customers to decide between these technologies. Ultimately LCD projectors provide far superior image quality and colour accuracy. The next paragraph will explain why DLP projectors struggle with bringing up a comparable level of image quality.
It’s like a set of blinds in your house on your bedroom window. By pulling a rod you can turn the shutters open or closed, depending on whether you want to let light in or not. And such is exactly how an LCD projector operates. Each pixel works like an individual shutter on a set of blinds to either send light through or to block it. DLP on the other hand is created of millions of microscopic mirrors or ‘pixel elements’ as the experts like to call them. Each pixel element functions to either reflect light or block it.
How the light source is processed from when the projector switches on to when the image reaches your screen is extremely important for image quality, brightness and colour accuracy. LCD projectors process white light from the lamp by cutting 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 create the elements of the image by shining each pixel on and off. The pixels are then meshed in a glass prism to deliver the projector image. A point to know about LCD projectors is that all three colours are projected onto your projector screen at the same time. The way a DLP projector works is widely different and even the produced image comes out 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 forming an image creates a sequence of red, blue and green light. The millions of micro mirrors described above reflect the coloured light on the pixels to construct the image elements. The elements of the image are projected in sequence on the screen, one colour at a time. The viewer’s eyes will then pull together each coloured element of the image into the single whole image. With LCD projectors, all colours are available all the time to form the best brightness and great colour accuracy. In DLP, just one colour is available at a time, and so resulting in lower colour brightness and accuracy. Some designers have placed a white segment into the colour wheel to improve all over brightness, but this then lessens colour accuracy.
I read in forums all the time that DLP gives a higher contrast ratio and ergo must be better. For those who are uncertain, 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. DLP projectors do possess high contrast specifications as compared to many LCD projectors. Initially, this seems to be a plus, however, in truth, the true black level is determined by the ambient light in the room in which 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 needs moving images, DLP projection technology can also create image marks, or ‘artifacts’. The most typical artifact that a DLP projector shows with moving images is colour break up. Colour break up is incontrovertible in DLP systems because moving images change between the time red, blue and green colours are shone. LCD projectors do not have this problem because all the colours are delivered with the others. DLP manufacturers have created 3DLP solutions using 3 chips to resolve the colour break up issue, but the price of these projectors make them impractical for the majority of businesses and consumers.
Another difference between LCD and DLP is how they balance for the refractive qualities of light. Remember back to high school science, and they taught you how different colours of light refract different amounts when passing through the same lens. The downside 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 not the same and refract light differently. Generally with a DLP projector, some yellow colour will be projected above and an extra blue will appear below an image as simple as a single black line. While being built LCD projectors can be adapted to minimize these effects on the projected image, because each colour is refracted on a separate LCD panels.
The sole true buy point (excluding price) with buying a DLP projector is its smaller size and weight. However, this is only relevant to portability and has to be traded off against the image superiority of LCD projectors. If the result of the picture quality is crucial to you, then the solution is a no-brainer. Choose an LCD projector! LCD projectors will always create bright, colourful images with fewer image blips. If you need to ask more about LCD technology in more detail, check out this tremendous 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 with Projector Central, Australia’s premier online store for projectors. Based in Brisbane, Projector Central has serviced Australia for 15 years. For data projectors in the Gold Coast and Interactive Whiteboards, contact Projector Central today.
Tags: data projectors brisbane, data projectors gold coastJuly 19th, 2010UncategorizedRead More >No Comments