The terms below are the ones that turn up on a quotation, a technical sheet or a supplier data sheet and are assumed to be understood. Where a term has a fuller treatment elsewhere on the site, the definition links to it rather than repeating half of it.
A
- Aspect ratio
- Width divided by height. Worth stating as the true reduced ratio of the wall as built — a wall of 4 800 × 2 571 mm is 28:15, not 16:9, and a customer with a tape measure can tell.
B
- Binning
- Sorting LED dies by wavelength and brightness so that a panel is built from consistent parts. Replacement modules ordered later come from a different bin, which is why spares should be bought with the wall.
- Brightness
- Measured in nits (candela per square metre). Roughly 600–1 200 nits indoors, 1 500–2 500 in a sunlit interior, 5 000–8 000 outdoors. Higher is not better: an over-bright indoor wall is uncomfortable and is usually run dimmed, which wastes both money and greyscale.
C
- Cabinet
- The enclosure built from modules — the unit of a price list and the unit a wall is tiled from. See cabinet sizes.
- Calibration
- A per-pixel correction of brightness and colour, stored in the receiving card, that makes a wall of varying parts look uniform. Factory calibration is normal; recalibration on site after a repair is not always offered and should be asked about.
- COB
- Chip on Board: dies bonded straight to the module and sealed under resin, giving a durable, high-contrast surface. See packaging technologies.
- Common cathode
- A drive arrangement that feeds each colour its own supply voltage instead of one voltage for all three. It cuts wasted heat and power meaningfully, and is now normal on fine-pitch indoor product.
- Contrast ratio
- The ratio between the brightest white and the darkest black the panel produces. Largely a function of how much ambient light the surface reflects, which is a packaging question more than a driver one.
- Curve lock
- A mechanism on rental cabinets that lets adjacent cabinets be locked at a fixed angle to form a concave or convex wall, usually in one- or five-degree steps.
D
- Daisy chain
- Cabinets connected in series for data, one to the next, so the receiving cards form a loop back to the processor. The order of the chain is the cabinet numbering, which is why it snakes.
- Diagonal
- The corner-to-corner measurement, quoted in inches out of habit inherited from television. Useful for comparison with an LCD wall and useless for anything else.
- DIP
- Dual In-line Package: the through-hole lamps that made older outdoor screens look like grids of bulbs. Commercially finished. Software that still offers a DIP option has not been maintained in a decade.
- Driver IC
- The chip that switches current through the LEDs. Its refresh capability, greyscale depth and low-brightness behaviour set most of what people describe as the panel’s "quality".
F
- Fill factor
- The proportion of the panel surface that actually emits light. A low fill factor at a coarse pitch is what makes a screen look like a grid of dots up close, independently of the pitch itself.
- Flip chip
- A die mounted face-down with its contacts underneath rather than wire-bonded from above. Better thermal path and no bond wires to fail, common in COB and MIP construction.
- Front service
- Modules and power supplies removable from the front of the wall, usually magnetically. Essential where the wall is against a structure with no rear access, and worth a price premium there.
G
- Greyscale
- The number of distinguishable brightness steps per colour, quoted in bits. It matters most at low brightness: a wall dimmed to 20% on a 14-bit driver has far fewer usable steps than the headline figure suggests.
I
- IMD
- Integrated Matrix Device, usually four pixels in one package. A cost and robustness answer to fine-pitch SMD. See packaging technologies.
- Ingress protection (IP)
- Two digits: solids, then liquids. Outdoor front faces are typically IP65 or IP66; a rear-of-cabinet rating is often lower and is quoted separately, as in "IP65 front, IP54 rear".
- Inrush current
- The brief surge switch-mode power supplies draw at power-on. Enough cabinets on one breaker will trip it every morning, which is why sequenced power-up exists. See power and weight.
M
- Magnet module
- A module held to the cabinet by magnets so it can be pulled off the front with a suction tool. The standard fixing for front-service indoor product.
- MIP
- Micro LED in Package: micro-scale dies packaged individually and then surface-mounted, aiming for COB-class pitch with pixel-level repair. See packaging technologies.
- Module
- The LED sub-panel that carries the lamps. Several modules make a cabinet. Modules are what get replaced when something fails.
N
- Nit
- One candela per square metre. The unit brightness is quoted in. Not interchangeable with lumens, which measure total light output rather than light per unit area.
P
- Pitch
- The distance between the centres of adjacent pixels, in millimetres. The figure everything else is derived from. See the pixel pitch guide.
- Power supply unit (PSU)
- Converts mains to the low DC voltage the modules run on, usually one or two per cabinet. A common failure item and the reason spare PSUs belong in every offer.
- Processor
- The box that takes an input signal and maps it onto the wall, sized by total pixel count rather than by cabinet count. Also called a sending card when it is a card in a PC rather than a standalone unit.
R
- Receiving card
- The control electronics inside a cabinet that turn incoming data into pixel drive. Typically one per cabinet, and the item that carries the calibration data.
- Redundancy
- A second data path so that a broken cable or a failed card does not black out everything downstream of it. Usually a loop back to the processor, roughly doubling cabling. Standard on broadcast and stadium work.
- Refresh rate
- How many times per second the whole image is redrawn, in hertz. Invisible to the eye above about 1 000 Hz, and very visible to a camera: 3 840 Hz is a normal minimum for anything that will be filmed, 7 680 Hz for broadcast.
S
- Scan rate
- How many rows share one set of drive circuitry — 1/8, 1/16, 1/32. Lower scan means higher brightness and better camera behaviour at the cost of more driver electronics per square metre.
- Serpentine numbering
- Numbering cabinets left to right along one row and right to left along the next, so the sequence follows the data cable rather than reading order. What the drawing on an easyLED offer shows.
- SMD
- Surface Mount Device: one package per pixel, soldered to the module. The mainstream construction above about 1.2 mm. See packaging technologies.
- Spare parts ratio
- The proportion of modules, power supplies and receiving cards supplied as spares, conventionally one to two per cent of the screen value. Frequently given away as a goodwill line, and shown at zero on the offer so the customer sees it.
- Sub-pixel
- One of the red, green or blue emitters that make a pixel. Sub-pixel arrangement affects how a panel renders fine text and diagonal lines, and is not something a pitch figure reveals.
V
- Viewing angle
- The angle off-axis at which brightness falls to half. Typically quoted as horizontal/vertical, such as 160°/160°. COB and IMD hold up better off-axis than fine-pitch SMD.
- Viewing distance
- Three different figures — minimum, recommended and retina — that data sheets rarely distinguish between. See viewing distance.
- Virtual production
- Filming actors in front of an LED volume showing a rendered background, in place of green screen. Demands very high refresh, precise colour and camera-synchronised scan, and is its own product category.
W
- Warranty tier
- The length of cover, priced as a percentage surcharge on the screen line. Two years is commonly included; three and five years are surcharges. Check whether it covers parts only or parts and labour.
- White balance
- The colour temperature the wall is calibrated to, in kelvin. 6 500 K is the usual reference; broadcast work often asks for 5 600 K to match daylight-balanced cameras.