METHOD FOR DETECTING MERCURY SEALED IN STRAIGHT FLUORESCENT LAMP

摘要

PURPOSE:To detect the presence of a mercury mass sealed in a straight bulb during evacuation with high accuracy by comparing the optical amounts measured by two optical sensors while rotating or moving the sealed straight bulb. CONSTITUTION:Light from a light source 5 is irradiated upon the peripheral surface of a sealed bulb 1 and the amount of light transmitted by the bulb 1 is measured by optical sensors 3 and 4 which are located opposite to the light source 5. When a mercury mass 2 is located near the optical sensor 4, the optical amount measured by the sensor 4 is smaller than that measured by the sensor 3. The presence or absence of a mercury mass is determined by using a computer to compare these optical amounts. As the size and the position of the mercury mass is not fixed, the bulb 1 is moved by using a gauge 6 so that at least one of the sensors 3 and 4 always passes over the mercury mass 2. By the means mentioned above, the mercury mass 2 can be detected with high accuracy regardless of its density, size and position.