| 摘要 |
PURPOSE:To prevent the occurrence of exfoliation, cracking, etc. in a reflective film and raise the directly under-illumination of a lamp by forming a reflective film composed of a mixture of a double calcium phosphate, Ca4P2O9-Ca3(PO4)2, and a calcium halophosphate containing no activator on a part of the inner surface of a glass tube. CONSTITUTION:On a part of the inner surface of the ringlike glass tube 1, a suspension composed of a double calcium phosphate, Ca4P2O9-beta-type Ca3(PO4)2, a calcium halophosphate containing no activator, and a solution of cellulose nitrate in butyl acetate, etc., prepared by grinding them in a ball mill, is coated to form the reflective film 2, and then on the film 2, the fluorescent film 3 composed of white calcium halophosphate, etc. is formed. Thus, a straight glass tube can be formed into a ring shape without causing the exfoliation, cracking, etc., in the reflective film and therefore the directly under-illumination of the lamp can be raised. |
