filament irradiation location the infrared light beam that passed through zone p becomes an infrared light beam 61 e upon reflection by a mirror 65 the infrared light beam 61 e moves through the zone p and irradiates the original filament 1 at a position one hundred twenty degrees removed from the initial original filament irradiation location for the infrared light beam 61 c in the manner described above an original filament 1 can be evenly heated from symmetrically located positions that are one hundred twenty degrees from each other by generating three infrared light beam 61 a 61 b and 61 c another example of using an infrared light beam of the present invention in which an original filament is irradiated from multiple locations is shown in fig7 an example in which multiple light sources are used is shown using a plain view the infrared light beam 67 a radiated from an infrared ray irradiation device is radiated toward an original filament 1 in addition an infrared light beam 67 b radiated from a separate infrared ray irradiation device is also radiated toward the original filament 1 in the manner described above multiple inexpensive laser transmission devices that are stabilized with relatively small scale light sources may be used as a high power light source to provide radiation from multiple light sources now three light sources are shown in the figure but.