| 摘要 |
PURPOSE:To realize a small-sized, inexpensive part to be replaced by providing a detection window attachably and detachably to the detection surface of a device body and replacing only the detection window when the detection window wears to be damaged. CONSTITUTION:A plate body 13 where an excitation window 15 and the detection window 16 which are formed of quartz glass are arranged is fitted attachably and detachably to the detection surface 12 with screws 14.... When the excitation window 15 and detection window 15 wear to be damaged owing to the contacting of postal letters 19, the screws 14... are removed from the detection surface 12 and the plate body 13 is detached to replace only the excitation window 15 and detection window 16. It is not necessary to replace the detection surface 12 entirely as before, providing economy. Further, the excitation window 15 and detection window 16 are formed of quartz glass having high hardness and superior optical characteristics, so the replacement period is prolonged and the reliability is improved. |
