| 摘要 |
PURPOSE:To enable whether mercury exists in a sealed glass bulb or not to be easily checked securely without being influenced by the sealing method of the sealed glass bulb and the formed state of a phosphor by cooling a part of the sealed glass bulb compulsorily, and measuring optically the state of mercury condensed on the said cooling part. CONSTITUTION:Although mercury supplied into a sealed bulb 4 usually is rapidly evaporated, most part of the above mercury is condensed 10 on a cooling part, which is provided in the lower part of the bulb 4. Here, a light sensor 12 provided so that it faces to the condensed mercury 10 doesn't operate since light transmitted by the condensed mercury 10 doesn't reach to a given amount level. This means that a given amount of mercury is supplied to the sealed bulb 4. In contrast, when the area of the condensed mercury 10 is narrow or mercury is not condensed at all on the cooling part, the light sensor 12 operates since a sufficient amount of light becomes incident upon the sensor 12. According to the detection signal of the sensor 12, a second magnet coil 13 is excited a number of times, and mercury is supplied into the bulb 4. |
