| 摘要 |
PURPOSE:To measure the size of a mercury film, by using a group of light reception elements to detect light transmitted through a tube or bulb, and by counting electric outputs from the elements. CONSTITUTION:A mercury film 7 is projected to a group 15 of light reception elements in such a manner that the group vertically extends across the projected image 22 of the mercury film in the axial direction of a tube or bulb 1. The projected image 22 is clearly made independently of the color of light emitted by a fluorescent substance on the inside of the tube or bulb. Generally, the light transmitted through the tube or bulb 1 is white light with a constant optical output level. For that reason, there is a definite difference between the output level of the light reception element located inside the projected image 22 and that of the element located outside it. The outputs of the light reception elements located inside the projected image are counted to determine the length L of the image in the axial direction of the tube or bulb 1 to determine the size of the mercury film 7. The number of the light reception elements a1-an of the group 15 is made large to make their location interval small to accurately determine the size of the mercury film. According to this constitution, the accurate measurement of the size of the mercury film, the automation of detection of the mercury in a fluorescent lamp and the enhancement of reliability are enabled. |
