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The most typical question asked when purchasing a new projector for the home, office, or classroom is: would I buy an LCD projector or a DLP projector? LCD, which stands for ‘liquid crystal device’ and DLP, standing for ‘digital light processing’ are the two most common projector imaging technologies. With so many company brands and models available, it can be overwhelming for clients to make a choice between the two technologies. The fact is that LCD projectors provide far better image quality and colour accuracy. The article below will tell you why DLP projectors struggle with creating a similar rate of image quality.

Visualise a set of blinds in your room on your bedroom window. With the twist of a rod you can have the shutters open or closed, according to if you want to let light in or not. That is exactly how an LCD projector functions. Each pixel works like a unique shutter on a set of blinds to either allow light through or to block it. DLP on the other hand is made up of millions of microscopic mirrors or ‘pixel elements’ as the professionals 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 switched on to when the picture reaches your screen is ultimately important for image quality, brightness and colour accuracy. LCD projectors shine white light from the lamp by cutting it into red, blue and green components, by three mirrors which direct the coloured light to 3 separate LCD panels. The 3 LCD panels make the elements of the image by switching each pixel on and off. The pixels are then simultaneously processed in a glass prism to deliver the projector image. Something to know about LCD projectors is that all three colours are projected onto your projector screen at once. The way a DLP projector works is widely different and even the produced 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 method of creating an image creates a sequence of red, blue and green light. The millions of micro mirrors mentioned above reflect the coloured light on the pixels to form 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 put together each coloured element of the image into a single total image. From LCD projectors, all colours are available all the time to form high brightness and great colour accuracy. In DLP, just one colour is available at a time, and so causing lower colour brightness and accuracy. Some DLP manufacturers have added a white segment into the colour wheel to improve brightness generally, but this also damages colour accuracy.

I read in forums all the time that DLP provides a higher contrast ratio and as such must be superior. 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 projector is capable of producing. DLP projectors do have high contrast specifications as compared to most LCD projectors. At one glance, this can seem to be a benefit, however, in reality, the true black level is determined by the ambient light in the room while the projector is in use. Do not be duped by contrast specifications on websites and in brochures.

When the content you wish to project needs moving images, DLP projection technology can also have image imperfections, or ‘artifacts’. The most common artifact that a DLP projector forms with moving images is colour break up. Colour break up is to be expected in DLP systems because moving images change position between the time red, blue and green colours are shone. LCD projectors do not have this downside because all colours are projected at once. DLP builders have come up with 3DLP solutions using 3 chips to resolve the colour break up problem, but the cost 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. Jump back to high school science, and remember how the different colours of light refract various amounts when shone through the same lens. The downside with DLP projectors is that they utilise the one same panel with the same lens to project Red, Blue and Green. All 3 colours are obviously different and refract light in different ways. Most of the time with a DLP projector, some yellow colour will come through above and some blue will come through below an image containing something as simple as a lone black line. In manufacturing LCD projectors can be adapted to reduce these effects on the projected image, as each colour is directed on isolated LCD panels.

The isolated actual buy point (excluding price) with choosing a DLP projector is its smaller size and weight. However, this is only relevant to transporting the device and has to be traded off against the image benefits of LCD projectors. If overall picture quality is vital to you, then the answer is easy. Take an LCD projector! LCD projectors will always produce bright, colourful images with fewer image blips. If you desire to learn more about LCD technology in more detail, have a look at this fantastic resource website: Explore 3LCD. If you have any additional questions, jump onto Projector Central and send me an email.

Jonathan King is the sales and marketing manager with Projector Central, Australia’s leading online provider for projectors. Brisbane based, Projector Central has serviced Australia for 15 years. For data projectors in Brisbane and Interactive Whiteboards, contact Projector Central today.