Lighting has undergone a shift in recent years towards energy-efficient LEDs (Light Emitting Diodes). Compared to older fluorescent lamps LEDs are far more efficient – they convert more energy into light and waste less as heat. Display technology has also benefitted from this ‘green’ technology. In 2009 we started seeing the first LED-backlit screens aimed at general consumers. Since then the technology has gathered pace and is now the go-to choice for LCD (Liquid Crystal Display) monitors.
Although certainly beneficial when it comes to energy efficiency, the way that some manufacturers and retailers have promoted the technology has simply confused consumers. This article will look at some common misconceptions (or ‘myths’) and set the record straight with a healthy dose of reality.
Myth – LED and LCD are distinct technologies
Reality – in this case ‘LED’ simply refers to a backlight type used in modern LCD monitors and isn’t an alternative to LCD. Older displays used CCFLs (Cold Cathode Fluorescent Lamps) for their backlight.
Myth – LED gives monitors better contrast with deeper blacks and brighter whites
Reality – LED backlights can improve dynamic contrast performance because they can change their brightness very rapidly. Dynamic contrast is a measure of contrast over time using a dynamic backlight brightness setting. In other words the overall brightness of the monitor itself will change to coincide with changes in scene brightness. The industry standard and important setting for most users is static contrast, which is a measure of the ratio between ‘black’ and ‘white’ at a fixed brightness. This typically yields a ratio of around 1000:1 (3000:1 for Vertical Alignment panels) and isn’t influenced by backlight type.
Myth – LEDs give screens better colours
Reality – it’s just a light source. It dictates the colour gamut (potential range of colours) of a display and in this respect LEDs and CCFLs are now on par. The underlying panel and LCD technology is crucial to a monitor’s colour reproduction characteristics and the backlight doesn’t alter this.
So if the image performance characteristics aren’t improved by the use of an LED backlight, why have things moved in this direction? The main reasons are the environmental benefits. First and foremost is the improved energy efficiency. LED backlights typically offer a power saving of 30-40% over an equivalent CCFL design at the same brightness. They also produce less heat as a result, which can make a big difference if you consider an office or another room with multiple monitors close together. Another environmental benefit is that unlike CCFL bulbs, LEDs are free from mercury and can be more easily recycled.