COB
COB turns up in 3 fields: lighting, PCBs, shop slang. Here is what it means to the people in each one.
COB in lighting
Chip-on-Board: an LED array with many dies mounted closely under one phosphor layer, acting as a single compact source.
Chip-on-Board, an LED package in which dozens of small chips are bonded directly onto a substrate and covered by a common phosphor disk. It behaves like one bright, uniform source, ideal for spotlights and downlights with reflectors, giving one shadow and clean beam edges. The high lumen density demands good heat sinking, and the bare emitting surface has very high luminance.
"Switch the track heads to the COB version, the multi-chip ones throw six little shadows on the merchandise."
COB in PCBs
Chip-on-board, an assembly method where a bare semiconductor die is mounted directly to the PCB.
Chip-on-board is a packaging technique where a bare integrated circuit die is glued directly onto the circuit board and wire-bonded to copper pads. The entire assembly is then covered with a protective blob of black epoxy. This eliminates the need for individual IC packages, saving space and reducing manufacturing costs.
"The new LED matrix uses COB technology to pack the emitters tighter than standard SMD parts allow."
COB in shop slang
A deadline meaning close of business, usually the end of the standard workday.
Close of business. This abbreviation sets a deadline for the end of the current working day, typically 5:00 PM in an office environment. On shift-based shop floors, it usually translates to the end of the first shift or the moment the front office locks up.
"Get those inspection reports on my desk by COB or we can't ship the batch tomorrow."