You can’t choose a liquid-crystal display (LCD) without considering the backlighting. All LCDs require backlighting. The liquid pixels within them aren’t electroluminescent, so they can’t illuminate themselves. Instead, the liquid pixels require external illumination. The system responsible for producing this illumination is known as the backlighting.
The Basics of LCD Backlighting
Most LCDs feature bulbs behind the pixel layer. These bulbs serve as the backlighting. In some LCDs, the bulbs are arranged in rows and columns. In others, they are only attached to the perimeter edges.
The bulbs will illuminate the pixel layer in front of them. They’ll generate light that shines through the pixel layer, thereby creating visible images. While all backlighting systems consist of bulbs, though, different LCDs use different types of backlighting.
CCFL vs LED
There are two primary types of backlighting for LCDs: cold-cathode fluorescent (CCFL) and light-emitting diode (LED). In the past, CCFL was the primary type of LCD backlighting. CCFL bulbs are similar to regular fluorescent bulbs. They contain low-pressure mercury vapor. As electricity travels through the CCFL bulbs, the mercury vapor will release ultraviolet (UV) light.
LED backlighting is a newer type of LCD backlighting. LED bulbs don’t contain low-pressure mercury vapor. Instead, they consist of small diodes that illuminate in response to an electrical charge.
It’s important to note that there are several different types of LED backlighting used in LCD. Some of the most common include edge-lit, direct-lit, full array local dimming and local dimming. Regardless, they all leverage diodes that illuminate in response to an electrical charge.
Advantages of LED Backlighting Over CCFL Backlighting
More and more manufacturers are switching to LED backlighting for LCDs. It offers several advantages over CCFL backlighting.
The contrast ratio for LED-backlit LCDs is greater than that for CCFL-backlit LCDs. And with its strong contrast ratio, LED-backlit LCDs produce high-quality images.
LED backlighting types up less space than CCFL backlighting. You can find LED-backlit LCDs that measure less than a half-inch thick. CCFL-backlit LCDs are typically thicker.
LED backlighting is more energy efficient than CCFL backlighting. Both types of backlighting consume energy during use. But LED is far more energy efficient, resulting in cost-savings benefits for users. Some reports suggest that LED backlighting consumes up to 30% less energy than CCFL backlighting.
It’s also worth mentioning that LED backlighting lasts longer than CCFL backlighting. All LED bulbs are long-lasting — and the LED bulbs used in LCD backlighting systems are no exception. They can last for many years while providing the necessary illumination for an LCD’s pixel layer.