Efficient light injector

A method of forming a light injector assembly comprising:

• providing an elongate tube comprising a first end, an opposing second end, and a tube length there between, the elongate tube having an inner surface and a specularly reflective layer or film disposed adjacent to the inner surface, and a lambertian light source disposed adjacent to the first end;
• providing a tapered solid light guide, the tapered solid light guide having a light input end, an opposing light output end, and a total internal reflection surface defining a longitudinal outer surface there between, the light output surface having a larger circumference than the light input end, and the light input end includes an aperture extending into the tapered solid light guide defined by an aperture surface;
• and
• inserting the tapered solid light guide into the elongate tube such that the lambertian light source is disposed within the aperture and spaced apart from the aperture surface by a first air gap and the total internal reflection surface is spaced apart from the elongate tube inner surface by a second air gap, to form a light guide assembly and 97% or greater of light emitted by a lambertian light source is emitted from the light output end.