Patent ID: 8686401

Claim:
An ultraviolet irradiation apparatus comprising, in a vessel, a semiconductor multi-layered film element and an electron beam irradiation source for irradiating the semiconductor multi-layered film element with an electron beam, the vessel being hermetically sealed to have a negative internal pressure and having an ultraviolet transmitting window, wherein: the semiconductor multi-layered film element includes an active layer having a single quantum well structure or a multi quantum well structure of In x Al y Ga 1-x-y N (0â‰¦x<1, 0<yâ‰¦1, x+yâ‰¦1); the active layer of the semiconductor multi-layered film element is irradiated with an electron beam from the electron beam irradiation source, thereby allowing the semiconductor multi-layered film element to emit ultraviolet radiation out of the vessel through the ultraviolet transmitting window; and a following equation (1) is satisfied: 4.18 Ã—V 1.50 â‰¦tâ‰¦ 10.6Ã— V 1.54 Equation (1), where V (kV) is an acceleration voltage of the electron beam and t (nm) is a thickness of the active layer.