i have a uv a led with the following specification
optical watt 0.103W
beam angle 15 degrees
distance from surface 2.4cm
also the circle created by my calculation is 0.313 cmsq


is the irradiance 0.103/0.313?
i have attached spectral result test if that helps

 

 

i have a uv a led with the following specification
optical watt 0.103W
beam angle 15 degrees
distance from surface 2.4cm
also the circle created by my calculation is 0.313 cmsq


is the irradiance 0.103/0.313?
i have attached spectral result test if that helpsView attachment 302298

Hi,

That's the way i understand it but it's been a long time since i had to do any of this.

The power divided by the area such as in Watts/SquareMeter or Watts/SquareCentimeter, etc.
If you are dealing with an angle and a distance rather than given an actual area, then yes you would have to calculate the area first.