The typical question asked when acquiring a new projector for the home, office, or classroom is: should I purchase an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, which stands for ‘digital light processing’ are the two most popular projector imaging technologies. With so many different brands and types available, it can be confusing for the buyer to decide between the two technologies. The fact is that LCD projectors provide far superior image quality and colour accuracy. The article below will explain why DLP projectors struggle with bringing up an equal standard of image quality.
It’s like a set of blinds in your room on your bedroom window. By pulling on a rod you can make the shutters open or closed, depending on if you want to let light in or not. And such is exactly how an LCD projector behaves. Each pixel functions like an individual shutter on a set of blinds to either pass light through or to block it. DLP on the other hand is created of millions of microscopic mirrors or ‘pixel elements’ as pros like to call them. Each pixel element works to either reflect light or block it.
How the light source is processed from when the projector is switched on to when the content reaches your screen is ultimately important in regard to image quality, brightness and colour accuracy. LCD projectors project white light from the lamp by separating it into red, blue and green components, by three mirrors which transfer the coloured light to 3 different LCD panels. The 3 LCD panels form the elements of the image by switching each pixel on and off. The pixels are then simultaneously processed in a glass prism to form the projector image. A point to remember about LCD projectors is that all three colours are directed onto your projected surface at the same time. The way a DLP projector runs is widely different and even the produced image shows up is not the same. With DLP, white light from the lamp is projected through a rotating colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This way of projecting an image requires 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 displayed in sequence on the screen, one colour at a time. The viewer’s eyes will then combine each coloured element of the image into a single full image. In LCD projectors, all colours are available all the time to form high brightness and superb colour accuracy. In DLP, just one colour is available at any given time, causing lower colour brightness and accuracy. Some developers have included a white segment in the colour wheel to improve brightness generally, but this further damages colour accuracy.
I hear in forums all the time that DLP has a higher contrast ratio and ergo must be better quality. 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 machine is capable of. DLP projectors do possess high contrast specifications in comparison to the majority of LCD projectors. At a glance, this appears to be a plus, however, in truth, the true black level is determined by the ambient light in the room where the projector is being utilised. Do not be duped 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 have image imperfections, or ‘artifacts’. The most commonplace 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 between the time red, blue and green colours are projected. LCD projectors do not have this problem because all colours are delivered at once. DLP manufacturers have come up with 3DLP solutions using 3 chips to resolve the colour break up issue, but the expense of these projectors make them hardly practical for many businesses and consumers.
Another variance between LCD and DLP is how they make up for the refractive qualities of light. Take yourself back to high school science, and they taught you how the various colours of light refract various amounts when shone through the same lens. The disadvantage 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 at different levels. Most of the time with a DLP projector, an extra yellow colour will come up above and some blue will show below an image containing something as simple as a single black line. While being built LCD projectors can be adjusted to reduce these effects on the projected image, because each colour is directed on separate LCD panels.
The isolated veritable buy point (excluding price) with deciding on a DLP projector is its smaller size and weight. However, this is only relevant in regard to portability and must be traded off against the image advantages of LCD projectors. If the outcome of the picture quality is important to you, then the answer is no-brainer. Go with an LCD projector! LCD projectors will always show bright, colourful images with fewer image mistakes. If you want to ask more about LCD technology in more detail, have a look at this spectacular resource website: Explore 3LCD. If you have any persisting questions, get onto Projector Central and send me an email.
Jonathan King is the sales and marketing manager for Projector Central, Australia’s premier online store for projectors. Based in Brisbane, Projector Central has served Australia for 15 years. For data projectors in the Gold Coast and Interactive Whiteboards, contact Projector Central today.
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