Everything You Need to Know About Full-Array Local Dimming

The Basics: What Is Full-Array Local Dimming?

To understand FALD, one must first understand how LCD (Liquid Crystal Display) technology works. LCDs do not emit light on their own. Instead, they modulate light from a backlight system, allowing or blocking it at each pixel through voltage-controlled liquid crystals. That light source is almost always a grid of LEDs (Light Emitting Diodes) located behind the panel.

Full-Array Local Dimming refers to a backlight system in which multiple LEDs are spread across the entire rear surface of the panel, and divided into zones. Each zone can be dimmed or brightened independently based on the brightness of the image content in that region. This is unlike edge-lit TVs, where LEDs are placed only along the edges and light is dispersed across the screen using a light guide plate. FALD delivers far more precise control, allowing the TV to selectively reduce brightness in dark areas while boosting it in bright ones—dramatically enhancing perceived contrast and detail.

The Physics of Light Control: Emission and Modulation

FALD’s effectiveness is grounded in electromagnetic theory and wave optics. Light emitted by each LED is comprised of electromagnetic waves, which propagate in straight lines unless manipulated. In a traditional uniform backlight, this light illuminates the entire LCD panel equally, regardless of the image content. As a result, dark scenes often appear washed out, and highlights lack punch.

With FALD, the system is designed to dynamically adjust the intensity of light emission across discrete sections. This is achieved by controlling the current supplied to each LED array. According to Joule’s Law, the brightness of an LED is directly proportional to the current it receives. Reducing current dims the light output; increasing it makes it brighter.

Light from these LEDs passes through diffuser films, optical enhancement layers, and the LCD module, which modulates the light with the help of liquid crystals and polarizing filters. The net result is that the intensity of transmitted light varies by region, allowing brighter areas to shine while darker ones remain convincingly dim.

LED Materials: Chemistry and Stability

The LEDs used in FALD systems are typically based on inorganic semiconductor materials such as gallium nitride (GaN) for blue LEDs or indium gallium nitride (InGaN) for RGB arrays. These compounds are selected for their bandgap energy, which determines the wavelength (color) of emitted light when an electric field induces electron-hole recombination.

Each recombination event in the p-n junction of the LED releases energy as a photon, producing visible light. However, high-current operation over time can cause degradation due to electromigration, thermal stress, and quantum efficiency losses. To combat this, FALD systems use flip-chip LED packages with thermal vias and copper-core substrates to dissipate heat efficiently.

In advanced FALD TVs—especially those using Mini-LEDs—the chemical stability of the LED material becomes critical. Mini-LEDs operate at higher densities and require more robust dielectric encapsulation, passivation layers, and phosphor coatings to maintain long-term optical consistency.

Dimming Zones: Resolution Versus Precision

A key metric for FALD performance is the number of local dimming zones. Each zone typically controls a group of several LEDs that illuminate a specific section of the screen. More zones generally allow for finer granularity, which leads to better image precision. For example, a high-end 65-inch FALD TV might feature 1,000 or more zones, compared to fewer than 100 in older models.

However, the number of zones is not the only determinant of quality. The shape, size, and layout of zones matter too. Ideally, the LED grid aligns well with the pixel structure of the LCD panel, but due to the diffusive nature of light, there’s always some optical bleed between adjacent zones. This phenomenon can cause blooming, where bright areas spill light into nearby dark areas.

To mitigate this, engineers use light shields, black matrix films, and anti-reflective coatings to limit unwanted photon diffusion. The effectiveness of local dimming also depends on real-time processing algorithms that interpret incoming video signals and instruct the backlight accordingly, adjusting power and brightness values with millisecond-level responsiveness.

Temporal Response and Latency

One challenge in implementing FALD is managing the response time between the content signal and the backlight’s adaptation. If the backlight adjusts too slowly, you may see haloing artifacts or flicker. If it adjusts too aggressively, you risk contrast pumping, where the image appears unnaturally dynamic.

The LED dimming response itself is fast—on the order of microseconds. However, the limiting factor is often the LCD’s response time, which is typically in the millisecond range. To synchronize the two, display processors implement temporal smoothing algorithms, gamma mapping, and black frame insertion techniques to ensure the visual transition is smooth and seamless.

Some modern FALD systems also include motion estimation and compensation (MEMC) engines, which predict frame changes and proactively adjust backlight intensity to minimize artifacts. This tight integration of hardware and software is essential for delivering the fluid, high-contrast imagery expected from premium TVs.

HDR Synergy: FALD’s Role in Dynamic Range

FALD is especially critical in delivering high-quality HDR (High Dynamic Range) experiences. HDR content includes a much wider luminance range, from the darkest shadows to the brightest highlights. To display this properly, the TV must be able to reproduce both deep black levels and high peak brightness simultaneously.

Without FALD, LCD-based TVs struggle with global brightness trade-offs—if the entire backlight is dimmed for dark scenes, highlights are muted; if it’s brightened for highlights, black areas appear gray. FALD overcomes this by allowing localized luminance control, boosting brightness where needed while suppressing light in dark areas.

Combined with 10-bit or higher color depth and wide color gamut panels (like those using quantum dots), FALD enables LCD TVs to rival or even surpass OLED in measurable brightness and peak luminance, though OLED still retains the edge in absolute black levels due to its pixel-level emissivity.

Chemistry of the LCD Layer: Why Modulation Matters

Behind the dimming zones lies the liquid crystal layer—a sandwich of nematic or vertical alignment (VA) liquid crystals suspended between two glass substrates. These crystals align or twist in response to applied voltage, thereby rotating polarized light to allow or block it.

The effectiveness of FALD depends partly on the optical transmittance and contrast characteristics of these crystals. VA panels offer higher contrast but slower response times, while IPS (In-Plane Switching) panels provide wider viewing angles at the cost of some contrast. To maximize the benefit of local dimming, high-performance TVs often use advanced VA crystals with multi-domain vertical alignment (MVA) or dual-domain technologies.

The liquid crystals are coated with alignment layers made of polyimide, and the precise thickness and voltage control affect how much light is allowed through. For FALD to function optimally, these layers must modulate light consistently across a wide range of dimming scenarios.

Mini-LED Integration: FALD at the Next Level

FALD has evolved further with the rise of Mini-LED technology, where the individual LEDs used in the backlight are reduced to sizes around 100–300 microns, allowing for thousands of tiny light sources and up to 10,000 local dimming zones.

Mini-LED backlights require micron-scale PCB routing, multi-layer thermal substrates, and dense driver ICs to manage the complexity. Each zone must be precisely synchronized with the display’s signal processing to avoid lag, and thermal management becomes a critical concern due to the concentration of power in smaller areas.

The result is vastly improved control over local luminance, reduced blooming, and enhanced support for high peak brightness HDR formats like Dolby Vision and HDR10+. The high dimming resolution also improves tone mapping, the process of adapting high dynamic range content to the screen’s capabilities.

AI-Powered Zone Control: Intelligent Light Allocation

In 2025, many premium FALD TVs use AI-based image analysis to manage local dimming behavior. These systems analyze content in real time, identifying object edges, scene brightness, and motion vectors to inform the backlight processor.

Unlike basic grid-based systems that simply dim by luminance averages, AI-driven systems prioritize contrast preservation and content-aware dimming. For instance, if a small bright object appears against a dark background, the AI algorithm prevents surrounding zones from over-brightening, reducing haloing.

These algorithms rely on deep learning models trained on diverse visual content, running on dedicated neural processing units (NPUs) embedded within the display’s main processor. The goal is to mimic the human visual system by making backlight decisions that align with perceptual expectations, not just raw pixel data.

Limitations and Engineering Trade-offs

Despite its benefits, FALD is not without limitations. Cost and complexity increase with more zones, and the physical size of LEDs, even in Mini-LED systems, sets a limit on how small zones can be. There’s also a risk of visible transitions between zones, particularly in scenes with subtle gradients.

Additionally, FALD does not achieve true black in the way OLED can, because even fully dimmed zones may still emit some residual light. Contrast performance in dark rooms, while vastly improved, is still not as absolute as that of emissive displays.

Engineers continually work on reducing blooming, improving zone granularity, and minimizing latency. Future improvements may come from even smaller emitters—such as MicroLED backlight matrices—or from hybrid systems that combine FALD with pixel-level modulation, effectively blending the best of both emissive and transmissive technologies.

Conclusion: Lighting Intelligence for the Modern Age

Full-Array Local Dimming represents one of the most important advancements in the ongoing evolution of television display technology. While it may be hidden behind the glass, its impact on contrast, color, brightness, and immersion is profound. Through an intricate blend of semiconductor physics, materials chemistry, and optical engineering, FALD allows LCD-based displays to approach the quality of self-emissive screens—without some of the drawbacks such as burn-in or brightness limitations.

In 2025, the synergy between Mini-LED hardware, advanced dimming algorithms, and AI-enhanced signal processing makes FALD not just a feature, but a cornerstone of display performance. Whether you’re watching a starlit night in a cinematic masterpiece or tracking a fast-moving game HUD, FALD ensures that every photon on your screen is intelligently placed, precisely modulated, and beautifully displayed.

The future of TV brightness and contrast isn’t just about how much light you can produce—it’s about where you choose to place it, and how effectively you control it. That’s the true brilliance of Full-Array Local Dimming.