Taustavalolähteet

Taustavalolähteet, known in English as backlights, are essential components in many display technologies, particularly LCD screens. Their primary function is to provide illumination behind the pixels of a display, allowing them to be seen. Without a backlight, the pixels themselves would be transparent and invisible to the viewer.

Historically, the most common type of backlight was the Cold Cathode Fluorescent Lamp (CCFL). CCFLs are gas-discharge lamps that produce light when an electric current passes through them. They were widely used for their relatively low cost and good brightness. However, CCFLs have drawbacks, including a lifespan that can degrade over time, a tendency to flicker, and a less uniform light distribution compared to newer technologies. They also require a high voltage inverter to operate.

In recent years, Light Emitting Diodes (LEDs) have largely replaced CCFLs as the dominant backlight technology. LEDs offer several advantages, including significantly longer lifespans, lower power consumption, and improved energy efficiency. They also allow for thinner display designs and can be controlled with greater precision, enabling features like local dimming for enhanced contrast ratios and deeper black levels.

LED backlights can be implemented in different configurations. Edge-lit LEDs are placed along the edges of the display and use a light guide plate to distribute the light across the screen. Direct-lit LEDs, on the other hand, are placed directly behind the entire panel, offering more uniform illumination and better control for local dimming. The choice of backlight source impacts a display's brightness, contrast, color reproduction, power usage, and overall physical design.