The typical question customers ask when acquiring a new projector for the home, office, or classroom is: should I buy an LCD projector or a DLP projector? LCD, short 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 customers to decide between these technologies. The simple fact of the matter is that LCD projectors give far better image quality and colour accuracy. The following article will tell you why DLP projectors struggle with reproducing a comparable grade of image quality.

Imagine a set of blinds in your house covering your bedroom window. With the twist of a rod you can turn the shutters open or closed, depending on if you want to let light in or not. Such is exactly how an LCD projector functions. Each pixel operates like an individual shutter on a set of blinds to either send light through or to block it. DLP on the other hand is constructed 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 the point when the projector turns on to when the picture reaches your screen is extremely important to image quality, brightness and colour accuracy. LCD projectors direct white light from the lamp by separating it into red, blue and green components, by three mirrors which direct the coloured light to 3 individual LCD panels. The 3 LCD panels create the elements of the image by processing each pixel on and off. The pixels are then meshed in a glass prism to create the projector image. Something important to remember about LCD projectors is that all three colours are sent onto your projector screen at the same time. The way a DLP projector operates is widely different and even the final product of how an image looks is not the same. With DLP, white light from the lamp is processed through a turning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This approach to projecting an image casts a sequence of red, blue and green light. The millions of micro mirrors as mentioned above reflect the coloured light on the pixels to produce the image elements. The elements of the image are projected in sequence on the screen, one colour at a time. The viewer’s vision will then put together each coloured element of the image into the whole image. From LCD projectors, all colours are available all the time to form high brightness and spectacular colour accuracy. In DLP, only one colour is available at a time, resulting in lower colour brightness and accuracy. Some designers have included a white segment in the colour wheel to improve overall brightness, but this also damages colour accuracy.

I see in forums all the time that DLP gives a higher contrast ratio and therefore must be superior quality. 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 machine is able to produce. DLP projectors do possess high contrast specifications in comparison to a majority of LCD projectors. Initially, this must be a benefit, however, in the real world, the true black level is determined by the ambient light in the room where the projector is utilised. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you want to see needs moving images, DLP projection technology can also create image marks, or ‘artifacts’. The most often seen artifact that a DLP projector creates with moving images is colour break up. Colour break up is unavoidable in DLP systems because moving images keep changing between the time red, blue and green colours are shone. LCD projectors do not have this disadvantage because the colours are sent with the others. DLP manufacturers have developed 3DLP solutions using 3 chips to answer the colour break up error, but the price of these projectors make them impractical for most businesses and consumers.

Another differentiation between LCD and DLP is how they match the balance for the refractive qualities of light. Jump back to high school science, and remember when they taught you how various colours of light refract differing amounts when shone through the same lens. The problem with DLP projectors is that they utilise the one same panel for the same lens to project Red, Blue and Green. All 3 colours are not the same and refract light at different levels. Often with a DLP projector, a superfluous yellow colour will come through above and some extra blue will appear below an image as simple as a straight black line. While being built LCD projectors can be fixed to minimize these effects on the projected image, because each colour is projected on isolated LCD panels.

The sole actual plus (excluding price) with picking a DLP projector is its smaller overall size and weight. However, this is only relevant with regard to mobility and cannot be traded off against the image superiority of LCD projectors. If resulting picture quality is important to you, then the choice is a no-brainer. Choose an LCD projector! LCD projectors will always create bright, colourful images with fewer image imperfections. If you wish to learn more about LCD technology in more detail, have a look at this tremendous resource website: Explore 3LCD. If you have any other questions, go to Projector Central and send me an email.

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

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