The LED glossary is a complete reference for LED video walls, displays and illuminated signage: every technical term at two levels — first in everyday language with an example, then in technical depth with the numbers. If you are reading a quotation or choosing a display, this is where you can settle in minutes what pixel pitch, nits, IP65 or a receiving card actually mean.
LED glossary
The LED glossary is a complete reference for LED video walls, displays and illuminated signage: every technical term at two levels — first in everyday language with an example, then in technical depth with the numbers. If you are reading a quotation or choosing a display, this is where you can settle in minutes what pixel pitch, nits, IP65 or a receiving card actually mean.
55 terms · every definition at two levels: in plain English and in technical depth.
A
Asynchronous control
A simple, standalone way of driving a display: the LED wall stores the content itself (uploaded from a USB stick, say) and repeats it continuously without a computer attached. Perfect for a small shop-front message sign that only needs to show prices or offers.
Technical detail:In asynchronous control the controller card plays back content (images, text, simple animations) held in its own onboard memory, with no PC in the loop, uploaded over USB or via a Wi-Fi/GSM module, with scheduling. It is typically used on lower-resolution message signs and smaller advertising boards with a simple pixel layout, where real-time video playback and a high refresh rate are not required. Its limits are storage capacity (usually a few GB) and the fact that it cannot play complex, synchronised multi-screen content.
Automatic brightness control
A built-in sensor constantly measures the ambient light and adjusts the wall's brightness to match — brighter by day, gentler at night — so it never dazzles unnecessarily and never wastes electricity. Much like the screen on your phone adapting to the light around you.
Technical detail:Automatic brightness control (ambient light sensor, ALS) uses a light-sensing module that measures ambient conditions in real time and dynamically adjusts the wall's output brightness (in nits), usually along a predefined curve. It serves three purposes at once: visibility (enough brightness in daytime sun), reduced light pollution (no dazzle at night, compliance with local light-nuisance rules) and energy saving, because power draw is close to proportional to output brightness. It also slows brightness degradation significantly, since the chips spend far less time at maximum load.
B
Bin-matched LEDs
This means every LED in a wall comes from the same production batch, so their colour is guaranteed to match. Build a wall from mixed batches and you can get subtle but visible bands of differing colour and brightness across it.
Technical detail:Batch matching means the LED chips for a given project come from one production run (bin), selected within the same wavelength, brightness and forward-voltage range. Small chip-to-chip variation is an unavoidable by-product of manufacturing, even on a single line, which is why makers sort chips into categories by binning and pick a single bin and batch for one project where possible. A wall assembled from mixed batches can show banding or a blotchy mura effect, correctable afterwards only through partial software calibration — so guaranteed batch matching is a key quality criterion on larger projects delivered in several shipments.
Brightness degradation
LEDs dim over time — this is brightness degradation, a natural process for every light source, incandescent or LED alike. A good-quality LED wall keeps acceptable brightness for years, provided it is operated sensibly and not pushed needlessly to maximum output.
Technical detail:Brightness degradation (luminance decay) is the gradual fall in the light output of LED chips over operating hours, caused by material fatigue from continuous thermal and electrical load. For quality chips the typical commitment is L70 (70% brightness retention) at around 100,000 operating hours, which corresponds to more than ten years of continuous use under average conditions. The rate can be cut significantly by limiting duty cycle and peak brightness (through automatic brightness control, for instance) and by designing heat dissipation properly — so long-term brightness retention depends on operating practice as much as on chip quality.
C
CMS (content management system)
The CMS is the software or app you use to run the wall's content — upload a video, set a schedule, and the system plays it automatically. Think of it as a remote-control app that lets you change what the wall shows even from home.
Technical detail:The CMS (content management system) is the software used to upload, edit, schedule and remotely manage the LED wall's content, typically through a web interface or a mobile app, either cloud-based or over the local network. Modern systems support multi-zone layouts (video plus weather plus a news ticker at once), automatic proof-of-play logging, alerts on faults (pixel failures, power supply dropout) and central content management for several sites from a single account. An easy-to-use CMS is the main reason the fear of not being able to operate it is unfounded: most systems are intuitive even for a non-technical user.
COB (Chip on Board)
A newer way of building modules where the tiny LED chips are mounted straight onto the board instead of being individually packaged — rather like dabbing dots of paint onto a canvas in a single layer. The result is a tougher, higher-contrast picture than with conventional SMD modules.
Technical detail:In COB technology bare LED dies are placed directly on the surface of the printed circuit board and covered with a protective resin layer, with no individual packaging. This substantially reduces the number of vulnerable points (a common source of pixel faults), improves heat dissipation and produces deeper blacks and a higher contrast ratio, because there is no hard plastic package edge between pixels. COB panels are harder to repair at pixel level, but the surface is far more impact-resistant, which makes them excellent for rental cabinets and for outdoor units that are moved often. GOB is a related protective-coating approach; the difference lies in the die-mounting depth and in the manufacturing process.
Curved LED display
A curved LED wall is not flat: it forms a bent surface, which can be gently convex, concave, or even close into a full circle. In creative spaces, at events or on unusual façades it produces a striking, distinctive look.
Technical detail:A curved build requires a cabinet or module system with mechanically adjustable hinged joints (typically in ±5–10° steps), allowing concave or convex arcs and, in some cases, a full 360° circular wall. This capability is usually found on rental cabinets and on certain creative LED product families, where the joint between modules stays seamless even in a curved position. Curved walls may also need image-warping correction on the video processor side so that content does not appear distorted across the concave or convex surface.
Cabinet
The cabinet is one of the building blocks of an LED wall: a self-contained, mountable panel unit, many of which fit together to form the complete wall — rather like assembling a large picture out of Lego bricks. A standard cabinet is usually around 50×50 cm or 100×100 cm.
Technical detail:The cabinet is the basic mounting unit of an LED wall: a group of LED modules built into a metal frame (aluminium or magnesium alloy), fitted with a power supply, a receiving card and quick-lock fixings. Outdoor cabinets are usually made with die-cast aluminium housings and IP65 front protection, most commonly in 500×500 mm, 500×1000 mm or 960×960 mm sizes, weighing 8–15 kg each. Seamless splicing between cabinets and LED chips from a single production batch are both critical to an even, band-free overall image.
Calibration
Calibration is the process of fine-tuning the colour and brightness of every single pixel with precision instruments so that they match perfectly — as if each LED were individually adjusted to a common standard. Without it the wall can look patchy and uneven, even when every LED is working.
Technical detail:Calibration is a procedure carried out with an optical camera measurement system (Novastar CBox or a Colorlight calibration camera, for example) that measures and corrects brightness and colour deviations pixel by pixel across modules, cabinets and even individual LED chips. Factory pre-calibration is done during manufacture; on-site calibration follows installation or forms part of periodic maintenance, because LED ageing reduces the output of individual pixels at differing rates. Regular calibration considerably extends the visually uniform life of the wall and reduces visible blotching (the mura effect).
Contrast ratio
Contrast describes how deep the blacks are and how vivid the whites — the bigger the difference, the sharper and deeper the picture looks, especially in dark scenes. A wall with good contrast shows detail cleanly at night rather than reducing to a blur of light.
Technical detail:Contrast ratio is the quotient of the brightest white and the darkest black luminance, determined primarily by black-mask technology and by the low reflectance achieved through COB or GOB surface treatment. On outdoor walls exposed to direct sunlight the matte, low-reflection surface matters especially, because it is what preserves contrast in daylight rather than only under laboratory conditions in the dark. Contrast is also closely tied to viewing angle, since the angle of reflection affects the perceived black level when seen from the side.
Colour temperature
Colour temperature describes whether white appears warmer (more yellow) or cooler (more blue), measured in kelvin. It matters when you place several walls or displays side by side, because differing colour temperatures make one look yellowish and the other bluish even though both are showing the same white image.
Technical detail:Colour temperature expresses the tint of white in kelvin (K): lower values (3000–4000K) give a warmer, yellowish white, higher values (6500–9000K) a cooler, bluish one. On LED walls, factory calibration harmonises colour temperature across modules and cabinets so that no difference is visible over a large surface, usually setting it to a 6500K (D65 standard daylight) reference. Where a wall is assembled from different production batches or from LEDs of differing age, colour temperature deviation is one of the most conspicuous quality faults, and can only be partly corrected by later software calibration.
D
DIP LED
The older, larger, round-headed type of LED still seen on many message signs and older stadium boards. The image is not as sharp as on today's walls, but it is extremely rugged and copes well with rain and sun.
Technical detail:A DIP (dual in-line package) LED consists of three separately packaged red, green and blue chips soldered individually into the board, often with an epoxy protective coating. Its advantages are outstanding brightness and inherently IP65-grade sealing against moisture, which is why it is still typical on large-pitch (16–20 mm) extreme-outdoor advertising boards and message signs viewed from a distance. Its drawbacks are lower resolution because of the wide pixel pitch and a narrower viewing angle than SMD, so it is rarely chosen today for close viewing or video content.
DOOH (Digital Out-of-Home)
DOOH is the industry name for digital outdoor advertising space — think of the modern video-capable billboards around town or along the motorway, as opposed to a traditional static paper poster. An LED wall you let out as advertising space falls into this category.
Technical detail:DOOH (Digital Out-of-Home) is the market segment of outdoor digital advertising surfaces, replacing traditional static billboards with dynamic content that can be bought programmatically and driven by live data (weather, traffic, stock levels). The business model is usually slot-based (8–10 second advertising blocks rotating between several advertisers) and can be managed through automated ad-sales platforms (programmatic DOOH). For a wall owner this can be a secondary revenue stream: alongside their own content, part of the surface is sold to local advertisers.
Digital signage
Digital signage is the umbrella term for any digital screen showing information or advertising in a public space — in shops, office buildings, restaurants. An LED wall is one form of it, and the one that also works outdoors and at large sizes.
Technical detail:Digital signage is the collective term for centrally managed digital display systems placed in public or semi-public spaces, covering LCD screens, kiosks and LED walls alike, all driven through a CMS. Research indicates that well-executed digital signage has a measurable commercial effect: published case studies report sales uplifts of up to 29.5% and advertising recall up to 52% higher with the right content and placement. Within the digital signage category, LED walls are strongest in large-format, outdoor or high-brightness applications where visibility is the priority.
Duty cycle
Duty cycle describes how many of the 24 hours in a day the wall actually runs, and at what brightness — a wall driven round the clock at maximum brightness ages far faster than one used only in the evenings at moderate output. It directly determines how long the wall lasts.
Technical detail:Duty cycle is the combination of actual daily operating time and average brightness level, and it fundamentally governs the rate of brightness degradation as well as the terms of any warranty. Manufacturers' lifespan specifications (100,000 hours to L70, for example) normally assume a standard duty cycle such as 12–16 hours a day at 70–80% average brightness, so a wall run 24/7 at maximum output can reach the L70 threshold much sooner than specified. Deliberately planning the operating regime (automatic brightness control, scheduled night switch-off or dimming) therefore has a direct effect on long-term total cost of ownership.
Dead pixel
A type of pixel fault where a dot simply does not light at all — as if a bulb had burnt out. A few scattered dead pixels on a large wall are all but invisible to the naked eye, but a cluster of them can be distracting.
Technical detail:A dead pixel is an LED pixel whose three RGB chips, or the driver IC serving them, have failed completely, so the point stays black regardless of the content displayed. In quality warranties it is worth writing concrete figures into the contract for the permitted proportion of dead pixels and the replacement deadline — for instance, that the pixel fault rate must not exceed 0.1%, failing which the module is replaced free of charge. Dead pixels are more common where soldering quality is poor, where thermal cycling (freeze and thaw) is severe, or where an undersized power supply causes voltage fluctuation.
F
Front service
This means a faulty module or cabinet can be removed and replaced from the front of the wall, without dismantling from behind or taking the whole wall down. In tight spots — where the wall is built straight against a building, for example — it is essential, because there simply is no room to work behind it.
Technical detail:Front service is a cabinet and module design in which the panel is held by magnets or quick-lock fixings and can be lifted out and replaced from the front, with no rear access, usually in one or two minutes without tools. It is critical for installations built directly against a wall, a glazed surface or another obstruction, where there is no service corridor behind. The absence of front service is one of the most commonly discovered-too-late design errors: if it is not considered at installation, even a simple module swap can mean dismantling the entire wall.
Frame rate
The number of new frames appearing each second in the video — the higher it is, the smoother the motion looks, exactly as in film or video games. Most video content is produced at 25–30 frames per second, which is comfortably enough for LED walls.
Technical detail:Frame rate states the frame count of the source video signal per second (fps), typically 25/30 fps for PAL-derived content or 50/60 fps for livelier motion and sports coverage. The wall's controller must support the incoming frame rate for undistorted display, and this is independent of the wall's own refresh rate in hertz, which is the speed of physical pixel redraw. For displays carrying high-motion content such as sport or concerts, a 60 fps source and a suitable video processor are recommended to avoid judder.
G
GOB (Glue on Board)
GOB is a protective coating poured over the surface of the LED module, like a transparent shield. It makes the module washable and scratch-resistant, and means neither a child nor a stray football can knock the pixels out of it.
Technical detail:GOB (Glue on Board) is a transparent epoxy or silicone protective layer applied over the SMD LEDs and the panel surface at the end of manufacturing. It makes the module waterproof (typically IP65 on the front face), impact-resistant and scratch-resistant, while also reducing reflection and improving contrast. GOB is especially widespread in rental cabinets and in child-friendly, easily reachable installations such as shops and schools, because the surface can be cleaned and mechanically loaded without damaging the pixels.
Greyscale (bit depth)
Greyscale describes how many fine brightness steps the wall can distinguish per channel, from darkest to lightest — the more steps, the softer the transitions and the more lifelike the image, with less visible banding across a sunset sky, for example.
Technical detail:Greyscale depth (bit depth) states how many discrete brightness levels the controller can display per channel (R, G and B separately), typically 12–16 bits per channel, or 4096 to 65,536 levels, on today's professional controllers. Greater bit depth produces smoother gradients and better dark-tone reproduction, which matters especially with HDR content and cinematic video, because low bit depth causes posterisation, or stepped banding, in dark shades. Greyscale performance is also closely tied to PWM control frequency and to the processing quality of the video processor.
H
HDR (High Dynamic Range)
HDR means the picture can render very dark and very bright detail convincingly at the same time — a sunlit sky and the shadows both stay full of detail, instead of blowing out or sinking into black. On modern video content it gives a far more lifelike, deeper image.
Technical detail:HDR support is the ability of the LED wall and the video processor to display a wider brightness range and deeper greyscale resolution (typically 12–16 bits per channel) than standard dynamic range, from content encoded to the HDR10 or HLG standard. It requires high native brightness (usually 1500+ nits peak indoors), an adequate contrast ratio and HDR compatibility along the whole signal chain — source, video processor, sending card, module. On premium indoor products and virtual-production studio walls, HDR support is increasingly a baseline requirement rather than an extra.
HUB75
A standard connector and signal format through which the control electronics talk to the LED modules — a shared language that modules from almost every manufacturer understand. It is why so many LED modules are interchangeable.
Technical detail:HUB75 is a 16-pin (sometimes 8 or 40-pin) interface standard over which the sending and receiving cards pass serial RGB pixel data and control signals (clock, latch, output enable) to the LED module. Although not a formal industry standard, the overwhelming majority of manufacturers use it or its extended variant HUB75E, which gives a high degree of compatibility between modules and controller cards. The signal speed and the scan rate (1/8 or 1/16 scan, for example) directly affect refresh rate and therefore how flicker-free the image looks on camera.
I
IP rating (IP65)
The IP number tells you how well the unit copes with dust and water — vital on an outdoor LED wall, which has to keep working through rain, snow and dust for years. IP65 means fully dust-tight and able to withstand a jet of water from a hose.
Technical detail:The IP (ingress protection) code has two digits: the first covers protection against solid particles such as dust on a 0–6 scale, the second protection against water on a 0–9 scale. Outdoor LED walls should be at least IP65 on the front face (fully dust-tight plus resistant to water jets), with IP54 or IP43 typical at the rear, since the cabinet and support structure shield the back from direct precipitation. Indoors, IP30 to IP40 is sufficient. In a continental climate with freeze-thaw cycling, summer heat above 35°C and winter frosts below −15°C, an inadequate IP rating is one of the most common causes of failure, so it should never be overlooked in a tender or a quotation.
L
LED message sign
The classic single-colour, often red, scrolling-text display seen in shop windows and at petrol stations, showing prices, offers and opening hours. It is one of the simplest and cheapest LED solutions there is.
Technical detail:An LED message sign is a simple, usually single-colour (red) or few-colour, large-pitch (10–20 mm) LED display designed primarily for scrolling text, prices and promotional information, driven asynchronously with modest memory requirements. Its lower resolution and limited colour gamut rule out video or photorealistic content, but its low price and easy remote content updates over GSM or Wi-Fi keep it popular with retail, hospitality and service businesses.
LED module
The module is the smaller panel inside the cabinet on which the LED dots actually sit — the cabinet is the box, the module is the picture inside it. When a small area fails, it is often enough to change one module rather than the whole cabinet.
Technical detail:An LED module is a printed circuit board carrying the SMD or COB LED chips; typically 6–16 modules make up a cabinet, in sizes such as 250×250 mm or 320×160 mm. Fast module replacement — modular repairability — is one of the most important considerations for buyers, because a faulty module can be swapped on site in minutes given a suitable spares stock, without dismantling the whole cabinet. Batch matching between modules is essential, as LEDs from different production runs can show slight colour differences that appear as visible banding on the wall.
LED poster
An LED poster is a slim, portrait-oriented display that looks like a digital poster — ideal for shop entrances and foyers, wherever you want continuously updatable digital content in a space that used to hold a printed poster. Its narrow bezel makes the frame almost invisible; only the image shows.
Technical detail:An LED poster is a thin (typically 3–8 cm deep), self-contained portrait display unit, often supplied with castors or a stand, usually at 0.9–1.9 mm pixel pitch, with a built-in power supply and controller and often an optional touchscreen, aimed at retail and digital signage. Its low power draw, compact build and plug-and-play character make it particularly popular in retail environments where quick, mobile installation and frequent content changes for offers and campaigns are the norm.
LED chip
The LED chip is the smallest unit that actually emits light — one pixel consists of three of these tiny chips, in red, green and blue. The chip's maker and grade fundamentally determine the wall's brightness, lifespan and colour fidelity, which is why serious manufacturers always name whose chips they use.
Technical detail:The LED chip is the semiconductor light-emitting element whose manufacturer (Nationstar, Kinglight, MTC, Sanan, Cree and others) and quality grade fundamentally determine the wall's brightness, colour gamut, rate of brightness degradation and operating lifespan. Reliable suppliers publish the brand and the quality bin of the chips they use, because this is the strongest objective evidence against the fear of receiving cheap, unbranded goods. Alongside chip quality, batch matching matters too: chips from different production runs can show slight colour and brightness differences side by side.
LED video wall
LED video wall is the most general name for a large LED surface that displays true, lifelike video and moving images — unlike a message sign, which can only manage simple text. At concerts, in shopping centres and in sports halls this is the typical solution.
Technical detail:The term LED video wall refers to high-resolution LED display systems supporting the full RGB colour gamut and a high refresh rate, which display real-time moving images under synchronous control through a video processor. They are built from cabinets or modules and range in size from a few square metres to stadium installations of several hundred. The term distinguishes them from simpler static or scrolling-text displays such as message signs and basic LED posters, because it is optimised specifically for dynamic video content.
M
Moiré effect
The odd wavy, striped distortion that appears when you photograph or film an LED wall and the two grid patterns — the wall's pixel grid and the camera's sensor grid — interfere with one another. It is not visible to the naked eye, only on the recording.
Technical detail:Moiré is an optical interference phenomenon arising where two grids of similar frequency meet — the LED pixel grid and the camera sensor grid — producing wavy or striped distortion in the captured image. On walls designed for camera work and live broadcast it is minimised through a higher refresh rate (3840 Hz or more), an appropriate ratio of pixel pitch to camera distance, and matching the camera's shutter speed to the LED. For television studio backdrops in virtual production and broadcast this is a critical design consideration.
N
Nit (brightness)
The nit tells you how bright the display is — the higher the number, the better it cuts through sunlight. Your smart TV might manage 300–500 nits; an outdoor street-side LED wall can reach 5,000–6,000 so that it stays legible in midday sun.
Technical detail:The nit (cd/m², candela per square metre) is the unit of surface luminance. Indoor LED walls typically fall in the 600–1200 nit range, because the eye views them from close up and under artificial light. For outdoor installations in direct sun, a minimum of 4500–5000 nits is advisable, with top-tier products reaching 6000–8000 nits. Actual operating brightness should be matched to the time of day using automatic brightness control, because full brightness at night is intrusive and needlessly accelerates chip ageing.
O
Operating hours and lifespan
This tells you roughly how many hours the LED wall runs well before dimming appreciably — the basis for thinking in terms of years or decades. A wall rated for 100,000 operating hours can serve for 27 years or more at acceptable brightness even at 10 hours of use a day.
Technical detail:Operating lifespan is the running time until the LED chip reaches the manufacturer's stated L70 value, typically 80,000–100,000 hours for quality chips, which corresponds to 10–20 years or more of real service at normal use of 10–16 hours a day. It is important to distinguish the theoretical life of the chip from that of the complete system (power supply, control electronics, mechanical parts), because the weakest link — often the power supply or the cooling — can limit the practical lifespan. The stated life applies only under a suitable duty cycle with adequate cooling and maintenance (calibration and cleaning), which is why warranty terms always include operating requirements.
P
Power feed
The power feed is the main electrical connection point that supplies the whole LED wall — it has to be designed and installed before the wall arrives. On a larger video wall this is usually a separate job for a qualified electrician, with its own circuit protection.
Technical detail:The power feed is the connection and distribution point for the wall's entire electrical system. Sizing it means accounting for total peak draw (W/m² × total area), even loading across phases (three-phase distribution on larger walls) and the required fuse or MCB capacity. Typical figures for outdoor walls are 250–450 W/m² at peak and 80–150 W/m² on average (with automatic brightness control) — the same figures that underpin any monthly electricity estimate. Skipping or undersizing the power feed design is one of the most common installation mistakes, and can force expensive electrical rework after the fact.
Public space use permit
If your LED wall faces or overhangs public space — a street, a square, a façade onto the pavement — you will usually need permission from the local authority before installing it. It is not difficult, but it is worth starting early, because the process can take weeks. The rules below describe Hungarian practice; comparable requirements exist in most countries.
Technical detail:A public space use permit governs the extent to which an advertising carrier or display projects into, or looks onto, public space (street, square, pavement). In Hungary it is issued by the competent local authority, normally against a fee set by local by-law. The procedure examines size, brightness (light pollution), road-safety considerations such as not dazzling drivers, and often townscape fit as well. To avoid delays it is worth consulting the authority early in the design phase, before manufacturing is ordered, because retrospective authorisation can carry a fine or an order to dismantle. Comparable permitting regimes apply in Germany, Austria and Slovakia; the local rules should always be checked.
Price per square metre
The square-metre price is what you pay for one square metre of LED wall — the figure people most often ask for, though on its own it never tells the whole story: the support structure, the control system and the installation usually appear as separate items. Always ask for a quotation that itemises everything.
Technical detail:The price per square metre is the base price of the LED wall itself (cabinet plus module plus LED chip) and varies widely with pixel pitch, IP rating, brightness and build quality, with finer pitches costing more. A transparent quotation must list the support structure, the control system (sending and receiving cards, video processor), installation and any permitting fees on separate lines, because comparison on square-metre price alone is often misleading when those items stay hidden. For a realistic estimate of total project cost, the square-metre price should always be read in the context of the full turnkey system price.
Perimeter LED
Perimeter LED is the narrow, long strip of LED you see along the edge of sports pitches — football and handball especially — between the stands and the field of play, where the advertising rotates during the match. It reads well both live and on television.
Technical detail:Perimeter LED is a low, elongated (typically 90–100 cm high and many metres long), high-brightness LED strip system used at sporting events for static or rotating advertising. Key considerations are a high, broadcast-compatible refresh rate (at least 3840 Hz) and standardised height, since international federations such as UEFA and FIFA set requirements for dimensions and brightness. It is usually built from modular cabinets that assemble and dismantle quickly, so that it can be moved easily between fixtures.
Pixels per m² (pixel density)
This tells you how many LED dots there are in total on one square metre — the smaller the pixel pitch, the more pixels are packed into a square metre and the sharper, more detailed the image. It is a useful figure for comparing two walls of different pitch objectively.
Technical detail:Pixel density (pixels per m²) is derived from pixel pitch: the smaller the pitch in millimetres, the higher the pixel count per square metre and the greater the native resolution over a given area. As an illustration, a 2.5 mm pitch wall gives roughly 160,000 pixels per m², whereas a 10 mm pitch wall gives only about 10,000 — a fortyfold difference, which shows clearly why price rises so steeply as pitch falls. Considering pixel density together with the intended viewing distance protects the buyer from paying a great deal more for a pitch finer than the application needs, when the audience will be viewing from a distance anyway.
Pixel fault
This is when one or more tiny dots on the wall do not light as they should: they may stay permanently lit, not light at all, or flicker in the wrong colour. On a good-quality wall it is rare, and it can be repaired without replacing the whole panel.
Technical detail:A pixel fault is the failure of one or more of the three RGB channels of an LED pixel, which may show as a permanently lit (stuck-on) pixel, a completely dark one (a dead pixel), or a pixel with incorrect colour mixing. With quality manufacturers the acceptable pixel fault rate at handover is typically below 1 in 10,000, and the warranty commitment includes continuous pixel-fault monitoring, for example through Novastar NovaLCT software diagnostics. Module-level repairability and a stocked spare-module inventory determine how quickly a pixel fault can be put right on site.
Pixel pitch
This tells you how close you can comfortably stand to the LED wall: the smaller the number, the nearer you can be, because the dots are finer and more densely packed. A 10 mm pitch wall looks comfortable from 10 metres; a 2.5 mm one is fine from about 3.
Technical detail:Pixel pitch is the distance in millimetres between the centres of two neighbouring LED pixels, and it determines resolution and the minimum comfortable viewing distance. A rule of thumb puts the minimum viewing distance in metres at roughly two to three times the pitch in millimetres: 1 mm pitch is about 2.5–3 m, 10 mm pitch about 8–10 m. Outdoor signs read from a busy road are typically 6–10 mm; indoor close-viewing applications 0.9–2.5 mm. Pitch is inversely proportional to pixel density and directly drives cabinet cost: halving the pitch means roughly four times as many LED chips and driver ICs over the same area.
Power supply
The power supply converts mains electricity into a voltage the LEDs can tolerate and run on — every cabinet contains one or more. If it is undersized the whole wall becomes unreliable, so quality and adequate rating matter.
Technical detail:The power supply (typically a 5V DC switching unit) converts 230V mains alternating current into the direct voltage the LED chips require; its rating is given in amps or watts, with a cabinet's peak draw often 150–250 W. An undersized or low-grade power supply is the most common cause of early LED failure, voltage fluctuation and fire risk, which is why quality manufacturers build in 20–30% reserve capacity (derating) and use redundant supplies on critical, zero-downtime installations. Power feed design for the whole system must be based on peak draw — a full-brightness white image — not on average consumption.
Q
Quick lock
The quick lock is the fixing that lets cabinets be joined and separated in seconds, without tools — like a strong snap catch. It is what makes it possible to build and strike an event LED wall within hours.
Technical detail:A quick lock (cam-lock or toggle-clamp system) is a tool-free mechanical fixing that secures cabinets to one another and to the support structure, opening and closing with a single lever or screw movement. On permanent installations the quick lock is also a precondition for front service, since it allows a cabinet or module to be lifted out quickly for maintenance without rear access. In rental use the quality and wear resistance of the quick lock is critical, because a cabinet may go through a hundred rig-and-derig cycles in its life.
R
Receiving card
A small circuit board on the back of each LED module that receives the picture signal and decides which pixel lights up in which colour. When a module misbehaves it is often enough to swap this card rather than the whole panel.
Technical detail:The receiving card is the control board mounted behind a module or group of modules; it decodes the serial video signal arriving from the sending card and distributes it across the scan lines using PWM control. Cards from the common makers (Novastar, Colorlight, Linsn) support different maximum pixel loads (256×256 or 512×512 pixels per port, for instance) and different refresh rates (1920 Hz to 3840 Hz and above). Replacing a receiving card is one of the most frequent quick on-site repairs, which makes a front-service design and a stocked spares inventory critical to a fast service response.
Refresh rate
This tells you how many times per second the LED wall flashes to make the picture look continuous. The higher the figure, the less the image flickers when filmed or photographed — important if the wall will appear on television or in social video.
Technical detail:Refresh rate states how many times per second the LED wall redraws the complete image, measured in hertz. Entry-level indoor and outdoor products typically run at 1920–2400 Hz, which is flicker-free to the naked eye but can cause banding on camera, particularly at slower shutter speeds. For camera work, live broadcast or high-resolution capture, a minimum of 3840 Hz is advisable, and top-tier control systems reach beyond 7680 Hz. Do not confuse it with frame rate: refresh rate is the speed of physical pixel redraw, frame rate is the frame count of the source video.
Rental cabinet
A rental cabinet is an LED panel designed specifically for hire and for frequent rigging and derigging: lighter, tougher and far quicker to assemble than a permanently installed wall. Concerts, events and exhibitions use these, because they may be built and struck several times a day.
Technical detail:A rental cabinet is made from light alloy (magnesium or carbon-reinforced aluminium) with quick-lock connectors, curving capability and increased impact resistance, often with a GOB coating, to survive the stresses of frequent transport and assembly. It typically weighs 20–40% less than a fixed-installation cabinet of the same size, and calibration and colour matching can be done quickly, even on site, because different cabinet combinations end up side by side at different events.
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Scrolling text
Scrolling text is the effect where a message moves steadily from right to left (or the other way) across the display — classically the signature look of a message sign. It is a good way of showing a longer message on a small surface.
Technical detail:Scrolling text is a display mode in which textual content moves continuously across the screen at an adjustable speed, usually horizontally and occasionally vertically, allowing longer messages to be shown on a surface with limited pixel height. It is now a standard CMS function on modern video walls and LED poster displays too, combinable with static and video content, though it originates with LED message-sign technology.
Sending card
The brain of the control system: it takes the video coming from a computer or media player and distributes it to all the receiving cards in the wall. On a large video wall several sending cards may work together to handle the enormous image.
Technical detail:The sending card takes the signal from the video processor, or directly from a computer's graphics card, and distributes it over Ethernet (Cat5e/Cat6) to the receiving cards, across cable runs that can extend to thousands of metres with repeaters or fibre converters. A single sending card typically handles 1.3–2.6 million pixels per port depending on resolution and refresh rate; larger walls such as stadiums or shopping centres chain several sending cards or synchronise them through a multi-screen controller.
SMD LED
The LED type used today, in which the red, green and blue emitters are combined in one tiny surface-mounted component. Almost every current LED wall — much like your phone screen — is built this way, because it gives a sharper, more even image than the older type.
Technical detail:An SMD (surface-mounted device) LED is a packaged surface-mount component containing three RGB chips, soldered to the panel by automated production line. SMD technology displaced DIP LEDs in the mid-2010s because it allows a wider viewing angle (typically 140°/140°), more even colour mixing and much finer pixel pitch, down to 0.9 mm. Its drawback relative to DIP is lower inherent IP protection in an open build, so outdoors it is usually protected by surface treatment, a black-face design, or a GOB coating.
Scan rate
Scan rate describes how many rows of pixels the controller drives at once before moving to the next group — a technical detail an everyday buyer need not know, but one that indirectly affects how flicker-free the image looks on camera.
Technical detail:Scan rate (1/4, 1/8, 1/16 or 1/32 scan, for instance) states what fraction of the module's pixel rows the control electronics illuminates at any one moment, and how quickly it moves to the next group of rows. A lower scan rate (1/4, or close to static scan) allows a higher refresh rate and better camera compatibility, but requires more driver ICs and is therefore more expensive. Choosing the scan rate is a direct trade-off between manufacturing cost and camera-friendly, flicker-free display, which makes it an important question for walls destined for live broadcast or a television studio.
Synchronous control
The mode in which the LED wall continuously mirrors, live, the picture from the computer or media player attached to it — exactly like an enormous monitor. This is what you need for video, live broadcast or anything requiring real-time display.
Technical detail:In synchronous control the video processor and sending card pass the content of the source (PC, media server, camera, HDMI or SDI input) to the wall continuously and in real time, frame by frame, with no storage. This is what makes full-resolution video, live broadcast and real-time mixing of several sources possible, for instance a sports event and advertising in split-screen. The refresh rates of the source and the LED wall must be matched, otherwise banding can appear in camera footage.
Support structure
The support structure is the metal frame or stand that holds the LED wall in place and carries both its weight and the pressure of the wind — no small matter, since an undersized support can be a serious safety hazard. It can be designed for a building, a pole or a free-standing frame.
Technical detail:The structural design of the support must always be based on the total mass of the wall (typically 15–35 kg/m² depending on cabinet type), the wind-load classification of the site and the applicable building standards (Eurocode with the relevant national annex), with a structural engineer's report for outdoor, elevated or large-area walls. Undersizing the support structure is one of the most common buyer errors with the gravest consequences: it is not enough for the LED wall itself to be of good quality if the frame behind it cannot take the real load in a storm. Ventilation clearance between the wall and the façade is also part of support design, because heat dissipation affects LED chip life.
Scheduled playback
This means setting in advance which content appears when — one thing in the morning, another in the evening, something different again at the weekend, all automatically and with no manual intervention. Rather like a programmable coffee machine, but for advertising.
Technical detail:Scheduled playback is a CMS function that starts and stops content blocks and playlists automatically by date and time (time of day, day of the week, public holidays), with weekly or monthly recurring patterns if needed. In digital signage and DOOH environments it is what makes daypart-targeted messaging possible — a breakfast menu versus an evening offer — and what rotates advertising slots automatically according to contracted share of loop. Scheduling is also used for energy saving, through night switch-off or dimming.
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Townscape notification
A further official step, by which you notify the local authority that you intend to install a visible fixture affecting the appearance of the townscape — a large LED wall on a building façade, for instance. Not every case requires consent, but failing to notify can result in a fine. The description below follows Hungarian practice; most countries have an equivalent.
Technical detail:The townscape notification procedure is required under local townscape by-laws for structures, advertising carriers and fixtures that materially change the appearance of a building or an area, which can include a large LED wall on a façade. It is separate from building control but similarly formal: documentation must be submitted (a visualisation and a technical description), and the municipal chief architect or the competent committee rules on it, usually within 8–15 working days. Failure to notify allows the authority to impose a fine and order restoration of the original state, that is, removal of the wall — a serious risk that is worth clarifying with the manufacturer or contractor in advance. Germany, Austria and Slovakia operate comparable local advertising-installation rules.
Transparent LED display
A special LED type you can very nearly see through, as through glass — the rows of LEDs are sparsely spaced on thin wires or strips, so the space behind them, a shop window or glass wall, stays visible. Excellent for shop windows where you want to advertise without blocking the view.
Technical detail:A transparent LED display is a specially sparse panel in which the LED chips sit on thin horizontal strips or wires, typically 4–10 mm wide, giving 65–90% light transmission to the background. It is mounted primarily on glazed surfaces such as shop windows or high-rise façades, because it does not obstruct the space or the view behind it while still showing content that is legible by day. Pixel pitch is usually coarser (3.9–10 mm) but brightness must be high (4000+ nits), because the light is emitted directionally from a reduced surface area.
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Viewing angle
This tells you from how far off to the side the picture still looks vivid and legible — if the wall fades or shifts colour when seen at an angle, its viewing angle is narrow. On a busy road or in the middle of a square this matters enormously, because most people will see the wall obliquely.
Technical detail:Viewing angle is the horizontal and vertical angular range within which brightness stays at least at half (50%) of its on-axis value. Modern SMD LED modules typically achieve 140°/140° (horizontal/vertical), which in practice means undistorted viewing up to ±70° off-axis. For high-traffic spaces, motorway-side boards or stadium perimeters this parameter can matter more than raw brightness, because with a narrow viewing angle a large share of the audience sees a distorted or washed-out image.
Video processor
A device sitting between the source — a laptop or camera, say — and the LED wall, which converts, stitches and sharpens the picture before it reaches the wall. It acts rather like a conductor, tailoring every input signal to the wall's size and format.
Technical detail:The video processor scales input signals (HDMI, SDI, DVI, DisplayPort, IP stream), matches resolutions, sharpens the image, handles HDR processing and mixes or splits several sources before passing the signal on to the sending cards. On professional event-technology and permanent installations (Novastar VX/MCTRL, Brompton, Colorlight) it is indispensable for seamless source switching and colour-calibrated, uniform output, especially where cabinets from several manufacturers or batches have to be harmonised on one wall.
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Wind load
Wind load measures the force the wind exerts on the LED wall, which the support structure has to withstand — the larger the wall and the higher it sits, the greater the forces in a storm. It is therefore far from irrelevant whether a design accounts only for weight or for wind as well.
Technical detail:Wind load is calculated from the installation height, the size and shape of the surface (a perforated surface such as transparent LED carries less load than a solid one) and the local wind-speed zone, in accordance with Eurocode EN 1991-1-4. In Central Europe the basic wind speed is typically 23–25 m/s. For large-area LED walls mounted high up, on a building façade or a roof, an engineer's structural calculation is mandatory, because the dynamic load from wind is the governing factor in sizing the support structure and the fixing points. Ignoring wind load is the design error with the gravest consequences, since it can create a safety hazard.
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