Technical differences between technologies?
Technology generations can be distinguished by their basic characteristics, and offer various degrees of lumen value.
The SMD (Surface Mounted Device) diode is currently the most widespread variant used industrially. Thanks to miniaturisation and output improvements SMD is able to offer satisfactory light output. Its major disadvantage is its susceptibility to temperature, which can reduce its lifetime dramatically.
COB/MCOB diodes are the response to the heat problem of SMD diodes with high outputs. The solution is a change in the technology for attaching the diode to the printed circuit board. While an SMD diode has its own casing which is stuck to the board, a COB/MCOB is stuck on directly using a special technique. This unique process reduces the heat demand of a diode by eliminating two layers and the contact resistance associated with them. The reduced temperature permits improved performance while retaining long lifetimes. MCOB is a derivative of COB.
Crystal is a unique technology where the LED is attached directly to a crystal base, allowing 360° illumination, while at the same time eliminating further layers and the contact resistance associated with them.