What Is Local Dimming? Edge-Lit vs Full-Array vs Mini-LED
Local dimming is when an LED-LCD TV dims parts of its backlight on their own, so the dark areas of the picture get less light while the bright areas stay bright. Instead of one backlight running at a single brightness behind the whole screen, the panel is split into zones that brighten and dim independently. The result is deeper blacks and stronger contrast, which is the single biggest thing separating a great LCD picture from a flat, washed-out one.
It matters because an LCD panel cannot fully block its own backlight. Even with the pixels "off", some light leaks through, so a uniform backlight leaves black scenes looking grey. Dimming the backlight behind the dark parts of the image is how an LCD gets closer to a true black. This is why two TVs both badged "4K HDR" can look nothing alike: the one with good local dimming shows a night sky as black with bright stars, while the one without shows the same scene as a grey haze.
There are three ways TVs do it, and the difference comes down to how many dimming zones there are and how small each one is.
The three approaches, compared
| Backlight type | Where the LEDs sit | Dimming control | Blooming | Typical price tier |
|---|---|---|---|---|
| Edge-lit | Around the rim of the panel | Coarse (few, large zones, sometimes none) | Most | Budget to mid |
| Full-array (FALD) | In a grid behind the whole panel | Good (more, smaller zones) | Less | Mid to premium |
| Mini-LED | Behind the panel, using much smaller LEDs | Best (far more, much smaller zones) | Least | Premium (now reaching mid) |
Edge-lit local dimming puts the LEDs along the edges of the screen and spreads their light across the panel with a light guide. Because the light is coming from the sides, the dimming zones tend to be large bars or columns rather than a fine grid. That makes control crude, so a bright object can drag a whole strip of the screen brighter with it. It is the cheapest approach and lets makers build very thin panels, but it gives the weakest black-level control. Some edge-lit sets have only a handful of zones, and plenty of budget sets have no real local dimming at all.
Full-array local dimming (FALD) spreads the LEDs in a grid directly behind the whole panel and groups them into zones. Because the light is coming from behind rather than the sides, each zone can control a smaller patch of the screen, so blacks hold up better and the halo around bright objects shrinks. This is the step up that most people notice.
Mini-LED is still full-array backlighting, but it uses much smaller LEDs. Shrinking the LED lets makers pack far more of them behind the panel and split the picture into many more, much smaller zones. More zones, controlled more precisely, means the tightest contrast and the least blooming of the three. It is why Mini-LED has become the go-to for a bright, high-contrast LCD picture. Among the sets we track, Mini-LED starts around $995 for a 55-inch as of July 2026, so it is no longer a premium-only feature.
Why more, smaller zones win
Each dimming zone can only be one brightness at a time. If a small bright object sits inside a large zone that is otherwise meant to be dark, the whole zone has to brighten to light that object, and the surrounding black turns grey with it.
Shrinking the zones fixes this. A smaller zone confines the light closer to the bright object, so the black around it stays black. The more zones a TV has, the finer that control gets, and the closer the backlight can approximate the ideal, which is controlling every pixel on its own. That is the whole reason zone count is the number worth chasing: more zones, each smaller, is better contrast and a cleaner image, especially in dark scenes and HDR highlights.
Exact zone counts vary a lot by model and are not always published, so treat any single figure with caution. As a rough guide, edge-lit sets often run from a handful up to a few dozen zones, full-array sets from tens into the low hundreds, and Mini-LED sets from several hundred into the thousands. The pattern is what counts: more and smaller is better.
Blooming, and why OLED does not have it
Blooming (also called halo) is the glow you see around a bright object on a dark background. It happens because a dimming zone is far bigger than a single pixel, so lighting one bright object lights up its whole zone and bleeds a halo into the black around it. You will notice it most on things like white subtitles on a dark scene, a bright moon in a night sky, or end credits.
More zones means smaller halos, because each lit zone is closer in size to the object it is lighting. That is the core advantage Mini-LED has over edge-lit and basic full-array sets.
OLED avoids blooming entirely because it has no backlight at all. Every pixel makes its own light and can switch fully off, so it is effectively per-pixel dimming. There are no zones to bloom. If you want the trade-offs between the two, see our guide on what OLED is and the head-to-head on Mini-LED vs OLED.
What to check before you buy
Backlight and dimming are often buried in the spec sheet or dressed up in marketing names, so it pays to check what a TV actually has:
- Is there real local dimming at all? Many budget LED TVs have none. Watch for "simulated", "pixel dimming" or software-only dimming that dims the whole backlight rather than real zones. That is not the same thing.
- Is it full-array or Mini-LED, not edge-lit? Edge-lit dimming is a long way behind. Full-array or Mini-LED is what you want for genuine contrast.
- Roughly how many zones? Where the number is published, more zones for the size is better. Where it is not, Mini-LED on a current model is a safe signal that the zone count is high.
For a full picture of how backlit LCD stacks up against plain LED sets and against Mini-LED, our explainer on Mini-LED vs standard LED-LCD covers it, and you can see the current Mini-LED TVs and prices we track.
The short version: local dimming is the biggest contrast lever on any LCD TV, and the number of dimming zones is what decides how good it is. Edge-lit is the weakest, full-array is a real step up, and Mini-LED gives the most zones and the cleanest result. If a set has no local dimming or only edge-lit dimming, that is usually the first sign its black levels will disappoint.
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