robincnn
Well-Known Member
Just some random info. Please feel free to correct me or post anything
To summarize
1) Handle COBS with care while installing cob and while removing glass lens. Good to read read these if you doing first DIY
AN 31 Bridgelux handing Vero
Cree CX Soldering and handling
2) If you bought a new COB light or made your own and see a cob that is less bright. It is pretty easy to take pics of Light Emitting Surface (LES). I use my phone camera and put my sunglasses in front of the phone camera.
A typical single diode LED, which has a hard epoxy case. They are pretty tough and don't go bad if you drop them.
However it is pretty easy to damage COB LES (Light Emitting Surface). The yellow phosphor resin area or the LES can easily get damaged if you drop anything on it. The LES has tiny connections that connect the multiple diodes within the COB. These connections can break due to stress or impact. The impact of a small M3 screw falling from an inch height may not be enough. However its best to avoid any stress on LES for maximum reliability and longer life of COB.
In this example we see how a string connection was broken after I accidentally
dropped a glass lens from a height of about 1 inch on the LES. The side of the lens hit the LES breaking the string connection. Such damage can happen if you are not careful during your DIY build or if the manufacturer of your light was not careful. When you turn on the light you cannot see these broken strings until you dimm your light to a very low current or take photo.
The COB still continues to perform however the efficiency goes down. I dropped the lens again on the other side to keep it symmetrical... just kidding. Will toss this COB out soon.
An interesting observation was that i did not see any noticeable change in current/ power. Indicating that the other strings were probably running at higher than average current, which would cause a decrease in efficiency. I measured this Vero 29 4000K COB(with 2 strings broken) against another Vero 29 4000K cob with PAR meter and saw about 10% less light with the damaged one. Veros are not binned and each Vero may differ from other in their output flux. Still 10% gives an idea.
Here is a pic from SDS post with welding mask glass. Perfect COBS
To summarize
1) Handle COBS with care while installing cob and while removing glass lens. Good to read read these if you doing first DIY
AN 31 Bridgelux handing Vero
Cree CX Soldering and handling
2) If you bought a new COB light or made your own and see a cob that is less bright. It is pretty easy to take pics of Light Emitting Surface (LES). I use my phone camera and put my sunglasses in front of the phone camera.
A typical single diode LED, which has a hard epoxy case. They are pretty tough and don't go bad if you drop them.
However it is pretty easy to damage COB LES (Light Emitting Surface). The yellow phosphor resin area or the LES can easily get damaged if you drop anything on it. The LES has tiny connections that connect the multiple diodes within the COB. These connections can break due to stress or impact. The impact of a small M3 screw falling from an inch height may not be enough. However its best to avoid any stress on LES for maximum reliability and longer life of COB.
In this example we see how a string connection was broken after I accidentally
dropped a glass lens from a height of about 1 inch on the LES. The side of the lens hit the LES breaking the string connection. Such damage can happen if you are not careful during your DIY build or if the manufacturer of your light was not careful. When you turn on the light you cannot see these broken strings until you dimm your light to a very low current or take photo.The COB still continues to perform however the efficiency goes down. I dropped the lens again on the other side to keep it symmetrical... just kidding. Will toss this COB out soon.
An interesting observation was that i did not see any noticeable change in current/ power. Indicating that the other strings were probably running at higher than average current, which would cause a decrease in efficiency. I measured this Vero 29 4000K COB(with 2 strings broken) against another Vero 29 4000K cob with PAR meter and saw about 10% less light with the damaged one. Veros are not binned and each Vero may differ from other in their output flux. Still 10% gives an idea.
Here is a pic from SDS post with welding mask glass. Perfect COBS
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