Diffusion Characteristics of Mercury Vapor in a Cold Cathode Fluorescent Lamp with a Small Diameter

The diffusion characteristics of mercury vapor in small-diameter cold cathode fluorescent lamps used for backlighting liquid-crystal displays have been investigated. A cold cathode fluorescent lamp in which the mercury was concentrated at one side of the lamp was operated at 50kHz AC, and the increase in light output at three different axial positions was measured. The inner diameter of the lamp was varied from φ1.2mm to φ3.8mm. The lamp current of each lamp was varied from 3mA to 10mA. Calculation of the mercury diffusion coefficient at each position showed that the mercury diffused more slowly the smaller the diameter and the higher the discharge current.