How Are the LEDs Arranged in LCDs?

It’s not uncommon for liquid-crystal displays (LCDs) to feature light-emitting diodes (LEDs). LCD isn’t an electroluminescent display technology. Only electroluminescent display technologies, of course, contain self-illuminating pixels. LCDs still have pixels, but they require a backlighting system to illuminate their pixels.

In the past, cold-cathode fluorescent lamps (CCFLs) were commonly used as backlighting systems in LCDs. While some LCDs continue to use this age-old type of backlighting, many of them have since switched to LEDs. They feature diodes that illuminate their pixels, thereby producing visible images. This post takes a closer look at LED backlighting systems and how the individual diodes are arranged in LCDs.

Edge Lit

When shopping for an LCD, you may come across the term “edge lit.” This term refers to the way in which the LEDs are arranged. Edge-lit LCDs leverage LEDs to illuminate their pixels. The LEDs, however, are specially placed along the edges of the LCD.

Most edge-lit LCDs leverage light guides. The light guides direct or “guide” the light to the pixel layer. When you turn on an edge-lit LCD, the LEDs on the sides will produce light. That light will travel through the light guides where it’s distributed to the pixel layer.

WLED Array

Some LCDs use white LED (WLED) backlighting. WLED is a type of full-array backlighting technology. Unlike edge lit, it doesn’t involve LEDs being placed along the edges or sides of the LCD. Instead, the LEDs are placed in a grid directly behind the pixel layer.

WLED receives its namesake from the use of white LEDs. LCDs with WLED backlighting feature a pixel layer. Directly behind this pixel layer is a grid of white-colored LEDs. When compared to other backlighting technologies. WLED is a popular choice because of its ability to selectively brighten or dim specific areas of the display.

RGB Array

In addition to WLED, there’s red, green and blue (RGB) LED backlighting. Also known as RGB array, it’s a type of full-array backlighting technology. Full-array backlighting technologies are characterized by the use of both rows and columns of LEDs. WLED and RGB are two of the most popular full-array backlighting technologies for LCDs.

The difference between WLED and RGB backlighting lies in their color. WLED consists of white-colored LEDs, whereas RGB consists of red, green and blue-colored LEDs. RGB involves a similar arrangement as WLED. Rather than featuring white-colored LEDs, though, it featured red, green and blue-colored LEDs. With these colors, RGB-backlit LCDs offer a wider color gamut than their WLED-backlit counterparts.