lense required to converge the viewing angle

[BushraSultana]

i need to converge the viewing angle of an Led from 120 degree to 60 degree, for this purpose i need to have a lense that converge the angle of 120 degree to 60 degree. so if someone can help me in finding that lense so please model no. of that lense is required.

 

[BradtheRad]

A compromise in one or another parameter will be necessary.

You could try ray tracing. Not in the sense of a rendering engine, but by drawing geometric diagrams on paper, and doing a few calculations, you would find which size lens to select, and what focal length, to do what you wish.

You would like to capture the entire 120 degree beam. The further away you place the lens, the larger it needs to be.

So you would like to place your magnifying lens close to the led. But the closer it is, the shorter its focal length needs to be.

The lens can be a couple inches diameter. Its focal length can be an inch or two. You will move it closer and further from the led, to get the results you want.

 

[BushraSultana]

thankyou, i will try to do so