| 摘要 |
PURPOSE:To reduce the production cost and improve the quality without lowering the reflection efficiency, by coating a reflecting part with a double-layer deposit film in such a manner that the whole of the reflecting part is coated with a first deposit layer which is relatively thin, and a second deposit layer having a thickness required to increase the reflection efficiency is formed on the first layer. CONSTITUTION:A lead frame 21 is formed by depositing copper 24 on the surface of an iron core material 23. A first silver deposit layer 25 is formed so as to cover the whole surface of a reflecting part 22. A second silver deposit layer 26 is formed on the silver deposit layer 25 at the upper end portion of the reflecting part 22. In other words, the reflecting part 22 has a double-deposit layer structure. Thus, the deposit layer at the upper end portion of the reflecting part 22 can have a thickness required to increase the reflection efficiency, and the thickness of the deposite layer on the other portion can be minimized. Accordingly, it is possible to reduce the amount of silver required for deposition without lowering the reflection efficiency, and the production cost can thereby be reduced. Since the whole surface of the reflecting part 22 is covered with the silver deposit layer 24, there is no fear of the reflecting part 22 getting rusty. |
