What makes a good illuminator?

Illuminators should perform three separate tasks along with a degree of efficiency.  Initially must house a lamp and its transformer, power source, ballast, wiring and igniter in a correct and safe way. Secondly, this must focus on the light of the lamp into the most efficient way to make sure an adequate performance. Thirdly, this should create an appropriate environment to guarantee the long life of the common end, it being the union with the fiber optics. Along with this last task in mind, an illuminator should be designed to minimize the thermal load upon the screen by all possible means, forced ventilation, filters, deflectors and air ducting.