Australian Content Blog

The common question asked when purchasing a new projector for the home, office, or classroom is: will I get an LCD projector or a DLP projector? LCD, an acronym 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 models available, it can be challenging for customers to choose between the two technologies. The fact is that LCD projectors provide better image quality and colour accuracy. The article below will tell you why DLP projectors struggle with bringing up the same rate of image quality.

Imagine a set of blinds in your room for your bedroom window. With the twist of a rod you can have the shutters open or closed, according to whether you want to let light in or not. This is exactly how an LCD projector behaves. Each pixel works like an individual shutter on a set of blinds to either shine light through or to block it. DLP on the other hand is made up of millions of microscopic mirrors or ‘pixel elements’ as the pros like to call them. Each pixel element functions to either reflect light or block it.

How the light source is processed from when the projector switches on to when the content reaches your screen is extremely significant in regard to 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 project the coloured light to 3 stand alone LCD panels. The 3 LCD panels cast the elements of the image by turning each pixel on and off. The pixels are then projected in a glass prism to deliver the projector image. A point to realise about LCD projectors is that all three colours are sent onto your projector screen all at the same time. The way a DLP projector runs is vastly different and even the final product of how an image shows up is not the same. With DLP, white light from the lamp is processed through a spinning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This way of projecting 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 cast in sequence on the screen, one colour at a time. The viewer’s eye will then combine each coloured element of the image into the full image. Using LCD projectors, all colours are available all the time to offer the highest brightness and superb colour accuracy. In DLP, just one colour is available at a time, and so causing lower colour brightness and accuracy. Some DLP designers have added a white segment in the colour wheel to improve overall brightness, but this then lessens colour accuracy.

I hear in forums all the time that DLP offers a higher contrast ratio and therefore must be better. 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 projector is capable of producing. DLP projectors do offer high contrast specifications as compared to a majority of LCD projectors. Initially, this seems to be an advantage, 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 tricked by contrast specifications on websites and in brochures.

When the content you are trying to project has 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 incontrovertible in DLP systems because moving images keep changing between the time red, blue and green colours are pulled up. LCD projectors do not have this characteristic because every colour is sent at the same time. DLP developers have formed 3DLP solutions using 3 chips to answer the colour break up issue, but the price of these projectors make them almost impossible for many businesses and consumers.

Another point of difference between LCD and DLP is how they compensate for the refractive qualities of light. Take yourself back to high school science, and they taught you how different colours of light refract various amounts when projected through the same lens. The downfall with DLP projectors is that they have the one same panel for the same lens to project Red, Blue and Green. All 3 colours are not the same and refract light in different ways. Most of the time with a DLP projector, a superfluous yellow colour will appear above and some blue will come through below something as simple as a single black line. During manufacturing LCD projectors can be set to reduce these effects on the projected image, as each colour is directed on separate LCD panels.

The sole veritable plus (excluding price) with buying a DLP projector is its smaller total size and weight. However, this is only relevant in regard to transport and needs to be traded off against the image plusses of LCD projectors. If resulting picture quality is vital to you, then the decision is a no-brainer. Go for an LCD projector! LCD projectors will consistently make bright, colourful images with fewer image mistakes. If you desire to learn more about LCD technology in more detail, check out this tremendous resource website: Explore 3LCD. If you have any persisting questions, visit Projector Central and send me an email.

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