Choosing the right display
Professional grade vs. consumer gradeWhen selecting a video display, you may find that “professional grade” or “commercial grade” models cost significantly more than televisions you can buy at the local high street electronic retail outlet. The primary difference is that professional grade displays are built to stay on 24/7 for weeks and months at a time without breaking down. They may also offer features such as video-wall processors, scheduling options, and lockable control panels not normally found in consumer-grade televisions. Professional grade also offer a 3 year onsite warranty and support as part of the package.
The most popular video display options
Liquid-crystal displays (LCDs) are a legacy choice for flat-panel video displays. These flat-panel displays consist of a liquid containing crystals sandwiched between filtering layers of glass or plastic. When electric current is passed through the material, the molecules of the liquid crystal twist so that they either reflect or transmit light from an external source, usually a cold cathode fluorescent lamp (CCFL). LCD displays have now largely migrated to newer LED technology. They can offer high brightness and are lighter making them easier to install and maintain. They are also the best choice for 24/7 applications because of their lower power consumption.
LED displays are actually LCD TVs that use LEDs as their light source, instead of traditional CCFLs and have become the most popular display option. In fact, these displays are often referred to as LED LCDs. LED displays tend to be brighter and perform better than LCDs. They lose less energy, run cooler and weigh less. Choose from slim edge-lit displays with a thicker bezel, or backlit displays which are thicker with a thinner bezel, but can offer enhanced picture quality through local dimming – where the LEDs behind the screen can vary in power individually to give blacker blacks and whiter whites.
Plasma flat-panel displays use small cells that contain electrically charged ionised gases, which fluoresce when electrically charged. Although plasma displays are waning in popularity and are available only in larger sizes— generally 42 inches and up—their deep blacks and high contrast ratios make them a good choice when implementing large displays that are intended to be eye-catching.
Other video display options
Older cathode ray tube (CRT) displays are still around; usually they‘re older Analogue TVs or VGA monitors. They‘re bulky, generally offer lower resolutions, and look very dated but can be a low-cost option in areas where appearance is secondary.
A front or rear LCD/DLP projector is a compact device that projects an image on a screen. These devices are handy for trade shows, meetings, or anywhere it would be impractical to bring along a full-sized monitor.
Organic light-emitting diode (OLED) displays are the displays of the future. They‘re lightweight, thin, and energy-saving but not yet available at a price that makes them practical for general use.
Video-wall specific displays
These can be LED video cubes or rear projection cubes that are designed to be stacked on one another for a virtually seamless video wall display.
Factors to consider when choosing a display
Plasma displays reproduce colour more accurately with deeper blacks and display moving images with remarkable clarity. They provide excellent performance with their high-contrast levels and colour saturation, and have the edge when it comes to viewing angles. In fact, plasma screens have as much as a 160° viewing angle, whereas LCDs display at 130–140° angles. However, they also carry the risk of image burn-in (the permanent disfiguring of a screen image caused by the continuous display of a high-contrast object). LCD displays, on the other hand, don‘t have quite the colour accuracy of plasmas, but they‘re brighter and have a sharpness advantage with a higher number of pixels per square inch. These additional pixels make LCD technology better at displaying static images from computers or VGA sources in full-colour detail. Applications with large amounts of data and written material display particularly well on LCDs. What‘s more, there‘s no risk of image burn-in.
With LCD screens, there are essentially no parts to wear out. They last as long as their backlights do, with displays lasting, on average, 50,000–75,000 hours. That‘s why LCD screens are especially good for applications such as digital signage or displays that require around-the-clock use. Plasma screens, however, use a combination of electric currents and noble gases (argon, neon, and xenon) to produce a glow, which in turn yields brilliant colour. The half-life of these gases, however, is only around 25,000 hours. The glow they produce grows dimmer over time. They‘re also prone to burn-in or ghosting of images, although this is less of a problem with newer models.
Early plasmas had a very high power consumption; some as high as 5W per square inch. These values are now down in the 0.3–1.0-watt range, depending on screen size. LCDs typically run in the 0.1–0.3-watt per square inch range, and LEDs are even lower. Manufacturers are now required to provide power consumption information, but keep in mind that there are two values for consumption, default and calibrated, so be sure you‘re comparing like values.
Making the choice
In general, plasma produces a clearer picture with a wider viewing angle and a better response time for fast motion playback, making it a good choice whenever you need a large screen to show a very visually active display, for instance, in applications displaying sports footage or active advertisements. LCDs are better at displaying detailed, static information. Because LCDs are brighter, they‘re ideal for venues with lots of ambient light. They‘re also the best choice for 24/7 applications because of their lower power consumption. For these reasons, LCDs are preferred for professional AV display installations.