Four names, four products
Pitch used to be the only axis anyone argued about. It is not any more. Two walls at 1.25 mm can differ in contrast, durability, viewing angle, repairability and price by more than two walls at different pitches — and the difference is packaging: how the light-emitting die gets from the wafer onto the panel.
There are four answers on the market as of 2026, and they are genuinely different products rather than four names for the same thing.
SMD
Surface Mount Device. Each pixel is one small package containing a red, a green and a blue die, soldered onto the module PCB by a pick-and-place machine. This has been the mainstream construction since the late 2000s and it still is, everywhere except the finest pitches.
Its limit is mechanical. As the pitch falls, packages get smaller and closer together, the machine places more of them per square metre, yield falls and the finished surface becomes fragile — a fingernail can knock a package off a very fine SMD panel. Below roughly 1.2 mm it stops being the economical answer, which is exactly where the other three live.
Above that, SMD is the right answer for almost everything: it is the cheapest per square metre, the easiest to repair pixel by pixel, and the only realistic construction outdoors.
IMD, or four-in-one
Integrated Matrix Device. Instead of one package per pixel, several pixels — usually four, sometimes two or nine — share a single moulded package. The pick-and-place machine now places a quarter as many components, and each one is larger and more robust than the SMD it replaces.
Practically, that buys:
- A cheaper panel than COB at the same pitch, because it is a cost reduction of a familiar process.
- A tougher surface than fine-pitch SMD, and better yield.
- Better contrast, because the package body is black and the gaps between pixels are darker.
And it costs one thing: repair granularity. A dead pixel means replacing a package that contains four of them, and matching the replacement to the surrounding bin is fiddlier than with SMD.
COB
Chip on Board. There are no packages at all. The bare dies are bonded directly to the module PCB and the whole surface is flooded with a protective resin, producing a continuous flat face with the LEDs sealed under it.
That construction changes several things at once:
- Durability. The face can be touched, leaned on, cleaned and in many cases washed. This is why COB dominates walls people can reach — reception desks, museum floors, retail.
- Contrast. A continuous matte surface reflects far less ambient light than a field of glossy packages, so blacks stay black in a bright room.
- Viewing angle. Wide and even, without the package-shadowing that narrows an SMD panel off-axis.
- Thermal behaviour. Heat leaves the die into the board directly, which helps lifetime at fine pitch.
The trade-off is repair. There is no package to lift off; a fault is fixed at module level, and colour-matching a replacement module to a wall that has been running for two years is a real problem rather than a theoretical one. Buy spares from the same production batch, and say so on the offer.
MIP
Micro LED in Package. The newest of the four and the one changing fastest. Individual micro-scale dies are transferred and packaged into very small packages, which are then surface-mounted much like SMD.
The appeal is that it keeps the two things COB gives up. Because the dies are binned and packaged before they reach the panel, colour consistency is controlled at the package stage; and because the result is still a surface-mounted component, pixel-level repair is possible again. It is positioned squarely at the pitches where COB has been the only option.
It is also the technology where claims and reality are furthest apart, because “micro LED” sells. Ask what the actual die size is and how the transfer is done before treating a MIP quotation as equivalent to a COB one.
Side by side
| SMD | IMD | COB | MIP | |
|---|---|---|---|---|
| Typical pitch range | 1.2 – 10 mm | 0.9 – 1.9 mm | 0.4 – 1.9 mm | 0.6 – 1.9 mm |
| Relative cost at 1.2 mm | Lowest, where available | Low | High | High |
| Surface durability | Fragile at fine pitch | Better | Excellent | Good |
| Contrast in a bright room | Moderate | Good | Excellent | Good |
| Repair granularity | Single pixel | Four pixels | Module | Single pixel |
| Outdoor use | Yes, the standard | Rare | Rare | Emerging |
| Best for | Everything above 1.5 mm | Cost-sensitive fine pitch | Walls people touch | Fine pitch that must be repairable |
Ranges and cost positions move every year and vary by supplier. Treat this table as the shape of the market rather than a specification, and check the current data sheet before quoting.
Choosing between them
Four questions settle it faster than any comparison chart:
- Can people touch it? If the wall reaches the floor in a public space, COB, and the conversation is mostly over.
- How bright is the room? A sunlit atrium punishes a glossy surface. Contrast — which means packaging — matters more there than another 0.3 mm of pitch.
- Who maintains it, and how? A wall behind a stage with no access needs pixel-level repairability and on-site spares. A wall in a lobby with a service corridor behind it does not.
- Is the pitch above 1.5 mm? Then SMD, almost certainly. The other three exist to solve problems that only appear below it.
And one commercial note: because these are different products at the same pitch, a competitor quoting “1.5 mm” against your “1.5 mm” may be quoting something substantially cheaper to make. Name the packaging on your offer. It is the fastest way to stop a like-for-like comparison that is not one — and it is a field the technical sheet should carry as a matter of course.
And DIP is gone
Dual In-line Package — the through-hole lamps that made outdoor screens look like grids of little bulbs — is finished as a commercial product. It was already residual by the late 2010s and it is not something you will be asked to quote.
If you are looking at a configurator, a price list or a piece of software that still offers a “DIP or SMD” choice, you are looking at something that has not been maintained in about a decade. The axis that replaced it is the one this guide is about.