He fits the diode into the lens, then glues the assembly into a hole drilled through the processor heat sink. A driver is built using the LM317 variable regulator, resistor, power supply ...

[tangentsoft] built a jig to test six LM317 regulators in constant current ... a regular Aavid TO220 heat sink, a set of 4 pennies bolted, a single penny epoxy glued and finally a single penny ...