The common question that is asked when looking for a new projector for the home, office, or classroom is: will I purchase an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two commonplace projector imaging technologies. With so many different brands and models available, it can be confusing for consumers to make a choice between both technologies. Ultimately LCD projectors provide far superior image quality and colour accuracy. The following article tells you why DLP projectors struggle with reproducing a comparable level of image quality.
Imagine a set of blinds in your home covering your bedroom window. By pulling on a rod you can turn the shutters open or closed, depending on whether you want to let light in or not. And this is exactly how an LCD projector behaves. Each pixel operates like its own 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 the professionals like to call them. Each pixel element works to either reflect light or block it.
How the light source is processed from the time the projector turns on to when the content reaches your screen is extremely significant with regard to image quality, brightness and colour accuracy. LCD projectors shine white light from the lamp by splitting it into red, blue and green components, by three mirrors which send the coloured light to 3 different LCD panels. The 3 LCD panels create the elements of the image by shining each pixel on and off. The pixels are then projected in a glass prism to deliver the projector image. A point to know about LCD projectors is that all three colours are delivered onto your projector screen simultaneously. The way a DLP projector operates is widely different and even the way an image looks 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 way of creating an image requires a sequence of red, blue and green light. The millions of micro mirrors as described above reflect the coloured light on the pixels to construct 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 combine each coloured element of the image into the single full image. Using LCD projectors, all colours are available all the time to create the highest brightness and spectacular colour accuracy. In DLP, only one colour is available at a time, and so resulting in lower colour brightness and accuracy. Some manufacturers have placed a white segment for the colour wheel to improve general brightness, but this goes and detracts from colour accuracy.
I find in forums all the time that DLP gives a higher contrast ratio and therefore must be superior. 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 able to produce. DLP projectors do possess high contrast specifications as compared to most LCD projectors. At one glance, this appears to be a plus, however, in reality, the true black level is determined by the ambient light in the room where the projector is being utilised. Do not be tricked by contrast specifications on websites and in brochures.
When the content you wish to project needs 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 to be expected in DLP systems because moving images change up between the time red, blue and green colours are displayed. LCD projectors do not have this problem because all colours are delivered with the others. DLP designers have created 3DLP solutions using 3 chips to answer the colour break up error, but the cost of these projectors make them almost impossible for the large part of businesses and consumers.
Another point of difference between LCD and DLP is how they match the balance for the refractive qualities of light. Remember back to high school science, and remember how different colours of light refract varied amounts when directed through the same lens. The downfall 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 different and refract light differently. Often with a DLP projector, an extra yellow colour will show above and a superfluous blue will come up below an image of something as simple as a straight black line. While being built LCD projectors can be adjusted to reduce these effects on the projected image, as each colour is processed on a separate LCD panels.
The sole veritable plus (excluding price) with going with a DLP projector is its smaller overall size and weight. However, this is only relevant in regard to transport and cannot be traded off against the image benefits of LCD projectors. If the outcome of the picture quality is crucial to you, then the choice is no-brainer. Go with an LCD projector! LCD projectors will constantly produce bright, colourful images with fewer image mistakes. If you need to ask more about LCD technology in more detail, have a gander at this spectacular resource website: Explore 3LCD. If you have any further questions, visit Projector Central and send me an email.
Jonathan King is the sales and marketing manager of Projector Central, Australia’s premier online shop for projectors. Brisbane based, Projector Central has been serving Australia for 15 years. For data projectors in the Gold Coast and Interactive Whiteboards, contact Projector Central today.