I have an old microscope illumination system with a ring-type fed by a fibre-optic cable. The illumination source is a power-hungry and hot projection lens.
I'd like to replace the light source with a 100W flat panel LED array (about 23mmx23mm). Ideally it would be good (I think) to focus the LED array light output to the fiber optic bundle end which is about 0.5" diameter.
I'm not certain what type of lens would do in this situation. Ideally I think one side of the lens would be flat, and sit against or near the LED array. I suppose it needs to be of glass or other material that can withstand heating ... I don't yet know how much.
Could use some practical suggestions as to lens types and a way to determine the distance between the LED array, the lens, and the LED light pipe for optimal performance.