| 摘要 |
PROBLEM TO BE SOLVED: To provide a shield structure for an optical filter whose earth electrode is not worn nor damaged due to external factors such as vibrations. SOLUTION: A 1st contact plate spring 4 with a stronger energizing force is fitted to the entire circumference of the optical filter and in contact with the entire ground electrode formed on the entire circumference of the optical filter, a 2nd contact plate spring 5 with an energizing force smaller than that of the 1st contact plate spring 4 is fitted to a frame 2, and the 2nd contact plate spring 5 is in contact with the 1st contact plate spring 4. Thus, when the frame 2 is vibrated through the vibration of the filter and the 2nd contact plate spring 5 fitted to the frame 2 is vibrated, the 2nd contact plate spring 5 and the 1st contact plate spring 4 are rubbed with each other, but the 1st contact plate spring 4 with the stronger energizing force is not vibrated through this rubbing thereby preventing the 1st contact plate spring 4 from rubbing a ground electrode and abrasing or damaging the ground electrode. |
