What type of Office Projector?

There are three types of projector technologies available on the market. DLP (Digital Light Processing) and LCD (Liquid Crystal Display) are the most widely available technologies, whilst LCoS (Liquid Crystal on Silicon) is a more recent technology that is becoming more popular.

DLP and LCD have few differences. DLP projectors are subject to the ‘rainbow effect’. This is due to the colour wheel they use to generate an image. This effect means that a very small amount of people will see flashes of solid colour. Faster colour wheels have reduced this substantially. DLP projectors can be a little awkward about where they are placed relative to the screen. LCD projectors are easier to place but also come with their own difficulties. LCD can suffer from ‘screen door effect’, the images sometimes look as though you are looking through a mesh panel. Experts tend to prefer DLP projectors as the black levels and contrast give a better cinematic picture but LCD projectors have a small price advantage.

The other type of Office Projector is LCoS. This is a newer technology than either DLP or LCD and is becoming increasingly popular. The LCoS technology has neither ‘rainbow effect’ nor ‘screen door effect’ and gives outstanding picture quality. However, it does tend to be more expensive than either DLP or LCD.

Another thing to look at is the resolution of the digital projector. SVGA (800p x 600p) and XGA (1024p x 768p) are the most popular. The XGA gives better, sharper text and graphics. SVGA is still available and cheaper than XGA and would give perfectly adequate pictures for the usual PowerPoint presentation. With the increase in wide screen laptops, the resolutions that fit them have changed. WVGA resolution (854p x 480p) matches that of DVD movies. There are other resolutions of similar size that come under the umbrella of WVGA. Many widescreen business projectors have WXGA resolution that matches many 14-15inch laptops. SXGA+ matches the larger computer screens and laptops over 17 inches.

Brightness is measured in lumens and basically, the larger the room the more lumens are required. Contrast ratio for most graphics and text is fine at 400:1 but for movies needs to be more than 1000:1.

Lamps can be quite expensive and they do need to be replaced periodically. Not surprisingly the lamps are rarely covered under the warranty for more than 90 days.