Spot Light for stereo microscope

I bought a used stereo microscope.
It is SZ type made by Olympus and it is a model of 30 years old.
Since the microscope had no lighting equipment, I made it by myself.

This micro scope is used for soldering the electronic circuit board.
Generally, ring light is used for illumination of a stereoscopic microscope.

However, when illuminating the Printed Circuit Board with a ring light,
surface of the PCB glows hard to see.
Therefore, the spotlight system was adopted.

The LED light bu