What is the black stuff on my LED bicycle light?

[ramonegumpert]

Dear experts, :)

I found a LED bicycle blinking light. The circuit is very small and it has a drop of, what i can only describe as, thick black dried 'ink' or glue or insulating material (as shown in the picture ) http://www.flickr.com/photos/46348930@N03/4257680841/ . I opened up another bigger LED light and it too has something like that. But i cannot see what is inside the black thing. The url again is : http://www.flickr.com/photos/46348930@N03/4257680841/

I a trying to find out what component so small is inside this drop of black glue/insulating matter.

So, could you kindly advise me what could be inside?

Thank you!

Sincerely
Ramone

 

[teslaguy]

Its a micro controller of some sort acting as a multivibrator. You could build your own with a 555 timer easily. you might be able to find a number on it if you heat the chip up and have an small knife. good luck.

http://en.wikipedia.org/wiki/Multivibrator"

 

[vk6kro]

We had a similar thread a month ago. There were some links in that one:

https://www.physicsforums.com/showthread.php?t=360893

But that picture wasn't as good as yours:

 

[Mike_In_Plano]

The black stuff is epoxy. Underneath is a chip that has jumper wires to the board. The process is called Chip On Board, or COB. In the past, it was the least expensive means of very high volume manufacture, but it's also one of the least reliable. Water vapor eventually gets in and poisons the chip, leaving you with something that can't be serviced.