Calculating IR Illuminator Power Output and Beam Area | Help on IR Light

[mchi5cf2]

Help on IR light please!

I want to know the Power that comes out of an IR Illuminator. The manufacturer only gives that power is 12mW at 85m. It also gives a beam angle of 35 degrees.


A. I took the surface area of the sphere generated by the illumination. That is 4*pi*(r^2)
B. The fractional beam area is calculated using the beam angle given and is (35/180)*(35/180)

C.So the area of the beam is the multiplication of A by B=C

In order to calculate Power you then calculate the result in C by 12mW(given) and you get a power of approxmitale 41 W.

Do you think my methodology is right ?Do you seggest anything??

I really need to work this out as it is essential for my project

 

[LowlyPion]

Welcome to PF.

When you say that the intensity is 12 mw what is the area of the detection that is determining 12 mw of power? Would that be 12mw/m²?

Since an IR illuminator projects light in a directed way, it would seem that the 12 mw summed over the area of a circle of radius 85m*sin17° would determine the intensity of the light projected at the source.