LED Chip on Board Assemblies
LED COB is defined as mounting an LED die(s), visible or infrared, directly to a printed circuit board as opposed to packaging the die in one of the standard options such as Surface Mount or Through Hole LED type packages. Depending on the chip type and structure, there are a few ways to properly attach or bond an LED chip to a pad of the PC board. Some of the more powerful chips available require a flux eutectic type attaching which limited vendors like Marktech can offer. Additional processes include wire bonding an electrical connection from the board to the LED chip and encapsulating the chip entirely to protect it from mechanical damage or contaminants.
Medical instrumentation is one business sector that benefits greatly from LED COB packaging. In applications like a medical endoscope for example, an illumination ring is needed on the end of a very narrow instrument. A COB light ring is the only feasible solution to pack enough chips to illuminate the subject matter taking into consideration that the instrument is a very narrow diameter platform and usually will have additional functions such as imaging to compete with for the same real estate.
In addition to using COB technology for illumination purposes, emission and detection functions of a sensor application can be greatly enhanced. With the ability to pack more light emission or light detection chips into an area, performance of the circuit can greatly increase.