COB LED Strips

COB strip carries hundreds of tiny emitters per meter under a single continuous phosphor layer. Instead of a row of separate diodes you get one unbroken line of light, which is why it has displaced SMD almost everywhere the strip itself can be seen — open coves, shadow gaps, handrails, reveals, and any shallow channel where a diffuser cannot sit far enough from the source to hide dots.

The trade-off is color. A COB strip mixes its phosphor across the whole emitting surface, which makes it excellent at uniformity and merely good at deep reds; where R9 has to be exceptional, or where the run has to change color, SMD still wins. For white architectural light in a visible position, COB is the safer specification.

Density is the number to read, not the marketing name. Chips per meter drives both the smoothness of the line and how much light you get per foot, and the two do not always move together — a high-density strip tuned for uniformity can be dimmer than a coarser one built for output.