| 摘要 |
PURPOSE:To make it possible to observe a measured substance formed in a substrate clearly and distinctly by installing a light transmission body which reflects and transmits illumination light emitted from a light source. CONSTITUTION:A part 1a of illumination light emitted from a sheet-shaped light source 9 is directly emitted vertically or virtually vertically at a mark 12. A part b of the light radiated on a vertical reflected plane 5 is emitted at the mark 12 at a high angle near to 90 deg.. A part c1 reflected on a reflected plane 6 enters a light transmission body 8 where the incident light penetrates partially through the light transmission body 8 as it is and it is emitted on the mark 12 at a considerably high angle. A part c2 of the light reflected on the reflected plane 6 is reflected on the surface of the light transmission body 8. After it is secondarily reflected on a reflected plane 7, the light penetrates through the light transmission body 8 and it is emitted at the mark 12 at a low angle. As described above, the light a, b, c1, and c2 having various angles is emitted at the mark 12, which makes it possible to observe the whole mark 12 clearly and distinctly. |
