The most common question customers ask when buying a new projector for the home, office, or classroom is: should I buy an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, short for ‘digital light processing’ are the two most common projector imaging technologies. With so many business brands and different types available, it can be challenging for customers to make a decision between those technologies. Ultimately LCD projectors offer far better image quality and colour accuracy. The next paragraph will tell you why DLP projectors struggle with bringing up the same rate of image quality.
It’s like a set of blinds in your house over your bedroom window. By pulling on a rod you can have the shutters open or closed, according to whether you want to let light in or not. And such is exactly how an LCD projector operates. Each pixel operates like its own shutter on a set of blinds to either shine light through or to block it. DLP on the other hand is formed of millions of microscopic mirrors or ‘pixel elements’ as pros like to call them. Each pixel element operates to either reflect light or block it.
How the light source is processed from when the projector is turned on to when the image reaches your screen is absolutely important to image quality, brightness and colour accuracy. LCD projectors process white light from the lamp by splitting it into red, blue and green components, by three mirrors which send the coloured light to 3 individual LCD panels. The 3 LCD panels create the elements of the image by shining each pixel on and off. The pixels are then simultaneously processed in a glass prism to deliver the projector image. Something important to realise about LCD projectors is that all three colours are sent onto your projected surface all at once. The way a DLP projector operates is very different and even how an image appears 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 method of forming an image forms 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 projected in sequence on the screen, one colour at a time. The viewer’s eye will then combine each coloured element of the image into a single total image. In LCD projectors, all colours are available all the time to form the top level of brightness and superb colour accuracy. In DLP, just one colour is available at a time, and so resulting in lower colour brightness and accuracy. Some manufacturers have included a white segment for the colour wheel to improve overall brightness, but this further degrades colour accuracy.
I find in forums all the time that DLP provides a higher contrast ratio and thus must be better. 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 projector is able to produce. DLP projectors do have high contrast specifications as compared to most LCD projectors. Initially, this seems to be a benefit, however, in reality, the true black level is determined by the ambient light in the room when the projector is in use. Do not be duped by contrast specifications on websites and in brochures.
When the content you wish to view has moving images, DLP projection technology also has image marks, or ‘artifacts’. The most common artifact that a DLP projector shows 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 pulled up. LCD projectors do not have this downside because all the colours are processed simultaneously. DLP manufacturers have come up with 3DLP solutions using 3 chips to solve the colour break up artifacts, but the price tag of these projectors make them impractical for many businesses and consumers.
Another variance between LCD and DLP is how they compensate for the refractive qualities of light. Think back to high school science, and recall when they taught you how different colours of light refract different amounts when passing through the same lens. The problem with DLP projectors is that they use 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, a spill of yellow colour will show above and some blue will come through below something as simple as a lone black line. In manufacturing LCD projectors can be adjusted to remove these effects on the projected image, because each colour is projected on isolated LCD panels.
The one true benefit (excluding price) with picking a DLP projector is its smaller total size and weight. However, this is only relevant for transporting the device and cannot be traded off against the image benefits of LCD projectors. If resulting picture quality is important to you, then the choice is simple. Choose an LCD projector! LCD projectors will consistently create bright, colourful images with fewer image errors. If you want to learn more about LCD technology in more detail, have a gander at this spectacular resource website: Explore 3LCD. If you have any additional questions, visit Projector Central and send me an email.
Jonathan King is the sales and marketing manager with Projector Central, Australia’s number one online provider for projectors. Brisbane-based, Projector Central has served Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.
Sphere: Related Content