Osram side-steps lack of LED second-sourcing
Osram has found a way around the lack of footprint standards amongst lighting LEDs, writes Steve Bush.
Solder pad patterns and shapes underneath lighting LEDs are not the same from different manufacturers, forcing users to re-lay their PCB if they change suppliers.
In a neat side-step, Osram is proposing a six-pad PCB pattern that will accommodate either the firm’s own Oslon LEDs, or one from another manufacturer (see picture), making it easier for customers to second-source LEDs while only stocking a single PCB.
“For ceramic LED components, to which the entire Oslon family belongs, Osram in Regensburg has developed a concept that makes the board solder pad design so adaptable that it can be used for LED components from at least two different manufacturers,” said the firm. “The concept can also be used for metal core, FR4 and ceramic boards.”
“Only a small adjustment to the process is needed, and the benefits are real and long-term,” added Osram development manager Dr Christian Gärtner.
The combined board design comes from the design of one of the two chosen LED components, with the individual solder surfaces divided into variously-connected segments.
By selecting appropriate spacings between the solder surfaces, the second LED product – rotated through 90° – can be attached to the same pads.
“By dividing the solder surfaces, the two LED types automatically align themselves to the edges of the solder surfaces during the reflow solder process,” said Osram. “For both LED components, the luminous area is in the same lateral position on the board: in the same alignment in the board plane.”
If the same secondary lenses and reflectors need to be used, the LEDs do have to have the same emission behaviour and effective source height.