PROBLEM TO BE SOLVED: To effectively form a film of photocatalyst by forming a photocatalytic film on the surface of a lamp in a specified thickness. SOLUTION: Titanium oxide is used as photocatalyst, and a liquid concentrate containing titanium oxide fine particles and a binder is applied onto the outer surface of a circular fluorescent lamp by a spray. The spray quantity is controlled to set the film thickness within the range of 0.3-0.8 m, and after the application, baking is performed at about 150 deg.C for 20 minutes to form a photocatalytic film. The photocatalyst should not be formed in the range of 7-13 mm from the base end in the base vicinity part on the outer surface of the lamp. When the application of the photocatalyst liquid concentrate is extended to the inside from the distance of 7 mm from the base end, the liquid concentrate or the vapor thereof is penetrated into the base to affect or corrode a lead wire. When the application exceeds 13 mm from the base end, the total source area of the photocatalyst film is reduced so that the photocatalytic action cannot be effectively exhibited. According to this lamp, the reduction in total luminous flux is as small as about 2%, and an excellent air cleaning effect can be obtained by the deodorizing effect.
展开▼
