To keep the external surface clean by forming a surface layer, which has a structure wherein both hydrophilic and water repellent parts are dispersed in a micro level, in the external surface of an electroluminescent tube or covers.
A surface layer having a structure in which hydrophilic parts so exposed as to bring photocatalytic oxide particles into contact with the outside air and water-repelling parts so exposed as to bring water-repellent fluororesin into contact with outside air are dispersed in a micro level is formed on the outer surface of a fluorescent lamp 1. With such as structure, since the hydrophilic surface areas and water-repellent surface areas are adjacent each other, hydrophilic adhering substances having affinity to the hydrophilic surface areas have no affinity to the water-repellent surface areas. To the contrary, hydrophobic adhering substances having affinity to the water repellent surface areas have no affinity to the hydrophilic surface areas. Consequently, both of hydrophilic adhering substances and water-repellent adhering substances do not adhere to the surface of the member and the surface can be kept in clean state.
HAYAKAWA MAKOTO
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