| 摘要 |
PROBLEM TO BE SOLVED: To prevent brightness in a central portion of a double tube type mercury-sealed cold cathode fluorescent discharge tube from lowering, even if the tube is used for a long period. SOLUTION: This double tube type cold cathode fluorescent discharge tube is composed of a luminous tube 11, an outer tube 12, beads 13, 14, a pair of discharge electrode 15, 16, and a pair of terminals 17, 18. Thicknesses of the electrodes 15, 16 and fixing parts 17b, 18b of the terminals 17, 18 are made smaller than those of outside projected parts 17a, 18a of the terminals 17, 18. Volumes of the electrodes 15, 16 are made 0.35 mm3 or less. Heating values in both ends of the discharge tube are increased, thereby to prevent the temperature in both ends of the luminous tube 11 from lowering, so as to uniformize the temperature in the tube 11.
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