Classic SMD LEDs (Surface Mounted Device) are tri-colour LED packages in a tiny plastic housing that are soldered individually onto the module PCB. This design reaches mechanical limits below a pixel pitch of approximately 1.2 mm: the solder joints become unstable, and the pixel failure rate increases disproportionately.

COB solves this problem by bonding the individual LED chips (dies) directly onto the substrate (PCB) — without an intermediate housing. Subsequently, the entire module surface is coated with a clear epoxy resin that protects the chips mechanically and electrically. The result is a completely smooth, deep black surface that is significantly more robust against touch, ESD, and dust than SMD.

Visually, COB offers three advantages: a wider viewing angle (up to 170° without colour shift), a more homogeneous image (no visible LED dots from up close), and a deeper black level (due to the continuous black carrier surface).

Economically, COB currently carries a surcharge of approx. 30–60% compared to comparable SMD. This surcharge is decreasing annually as more manufacturers (Samsung, LG, Unilumin, Absen, Leyard) scale up COB production. For pitch classes ≤ 1.5 mm, COB is now the de facto standard.

Common questions
about COB LED.

01Is COB worth it compared to SMD?+

For pixel pitches ≤ 1.5 mm, almost always — the robustness and image quality quickly justify the extra cost. At P1.9 and coarser, it depends on the environment: in high-traffic areas with a risk of contact, yes; for static lobby walls, SMD is often the more economical choice.

COB LED

Common questionsabout COB LED.

COB LED in your project?

Common questions
about COB LED.