LCD and Plasma displays have become more and more affordable over the last 10 years. Not only have the prices dropped, the displays have become lighter, thinner, more attractive and of course have come on massively in terms of picture quality.

Flat panel televisions are available with full HD resolution, superb contrast and technologies such as sub-field processing, frame insertion, dynamic contrast enhancment, localised backlight dimming and more - all of which promise to improve the detail and vibrancy of the picture. At Gear 7 we take something of a purist approach, though, preferring to select the best display and (generally) turning off all the processing!

Commercial display panels are also available in full HD resolution and can be weatherproof or even viewable in direct sunlight. Commercial plasma and LCD displays are designed to run 24/7 without over-heating or burning out. They are of a sturdier construction than consumer televisions and offer features such as video-wall setup, RS232 control, integrated digital signage playback and more.

LCD Panels & Televisions

LCDs fall in two main categories at present: CCFL backlit, and LED backlit. LED backlit LCDs are frequently referred to as LED televisions. It is important to note that 'LED TVs' are still LCD panels.

An LCD comprises two layers of glass between which are sandwiched small cells of coloured liquid crystal. A white backlight is positioned behind the LCD panel. Blacks and colours are achieved by energising the cells of crystal, turning them proportionally opaque.

The brightness of an LCD is therefore determined by the strength of the backlight. Standard LCDs use one or more flourescent lamps, combined with a diffuser, to produce and even backlight. LED backlit televisions use compact, high output, surface mount (SMD) LEDs to produce the same effect. Some LED backlit sets position the LEDs around the perimiter of the panel, whilst others position them directly behind. It is generally accepted that rear-lit LED-based sets perform better than perimiter-lit sets due to the more even luminance. A further advantage is that the brightness of LEDs may be controlled in groups to enhance the effective contrast ratio.

The contrast ratio of an LCD is dependent on the panels ability to mask/block the backlight. The native contrast ratio is defined as the difference in intensity of output from full white to full black, with the backlight at full intensity. Many modern LCDs use an intelligent backlight dimming algorithm to improve the perceived contrast ratio (a dark scene cause the backlight to dim, and vice-versa). The maximum contrast ratio achieved when this technology is employed is often referred to as the 'dynamic' contrast ratio. Always consider the native contrast ratio first and foremost when choosing a panel - 4000:1 native and 20,000:1 dynamic will almost always look better than 2500:1 native and 50,000:1 dynamic!

Liquid Crystal cells have an intrinsic response time. This is a measurement of the time it takes for a cell to become fully opaque after having full current applied to it. Poor response times manifest themselves as 'smearing' of motion and simply do not make for a good picture.

Plasma Display Panels & Televisions

Plasma displays work by essentially the opposite principal to LCDs. That is, there is no backlight. Each pixel comprises 3 cells filled with special gasses. When an electric current is passed through these gasses they change state to gas plasma and (by an interesting physical process) emit ultra-violet photons, which are then converted to visible light by collision with the phosphor lining of the cell.

This means that the native contrast ratio of a plasma display is nearly always better than that of an LCD panel. Furthermore, the emission of light is near instantaenous, meaning that plasmas generally do not exhibit motion smearing.

For home use, where a panel of 37" or more is required, we would generally recommend a plasma for this reason.

The downside of plasma displays is that their brightness is limited to the light output of each individual cell. For installations subject to direct sunlight or reflections, a plasma may simply not be bright enough.

Brands we supply

In the interest of upholding the highest standards of quality, at present we use and supply LCDs & plasmas from:

• NEC Display Solutions - Professional only
• Panasonic - Professional, Consumer
• Samsung - Professional, Consumer