| 摘要 |
PURPOSE:To prevent a detection pattern from being absent and to detect an accurate pattern by constituting the opaque part of the black line mask by a linear metallic member. CONSTITUTION:The black line mask 10 has light passage parts 13 and 14 formed across a linear center part 11 by punching one metallic plate of thickness (t) so that the linear part 11 of width (w) and a peripheral part 12 are left. The center part 11, therefore, operates as an opaque part and the use of the black line mask 10 forms a black line corresponding to the center part 11 on a printed board. Consequently, the center part 11 of the mask 10 as the opaque part maintains the sufficient thickness (t), so the light which is made incident on this part is cut off nearly completely. Therefore, the complete black lines is formed on the printed board and the detection pattern has no absence.
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