| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of forming fine piercing holes on a housing capable of accurately finishing the metal housing as an optically semi-transmissive/reflective panel. Ž<P>SOLUTION: A plurality of piercing holes 1 are formed on the housing 2, wherein a metal plate not optically transmissive is used for the housing 2, and the holes are used to transmit respective lights from a plurality of light-emitting elements 3 arranged at predetermined positions beforehand in the housing 2 to the outside of the housing 2. As a piercing hole 1, a fine front-surface hole 11 having a fine aperture diameter invisible to human eyes is formed on the front-side surface of the housing 2, and a rear-surface hole 12 having an aperture diameter different from that of the fine front-surface hole 11 and communicatively connected to the fine front-surface hole 11 is formed on the rear-side surface of the housing 2, through an etching work from respective surfaces. When the plate thickness of the housing 2 is denoted by T, and the aperture diameter of the fine front-surface hole 11 is denoted by A (where, T>A), the center axis of the fine front-surface hole 11 and that of the rear-surface hole 12 are made to coincide with each other, while the depth of the fine front-surface hole 11 is made to be A, the depth of the rear-surface hole 12 is made to be (T-A), and the aperture diameter of the rear-side hole 12 is made to be (T-A) or less. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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