Stanley Electric Co., Ltd

Hisataka Kondo

Tsuneyoshi Shibasaki

Kouji Kikuchihara

Ryuichi Suzuki

Masatoshi Chiba

A fluorescent lamp includes a bulb, a fluorescent material coated on an internal surface of the bulb, a stem, a discharge chamber filled with gas and mercury, a thermal cathode filament coated with electron emitting material, an anode, a pair of lead wires passing air-tightly through the stem and supporting the thermal cathode filament, and a lead wire supporting the anode. The anode is a substantially rectangular plate, and is substantially parallel to the thermal cathode filament in a cross sectional view taken along a bulb axis Z. The thermal cathode filament and the rectangular anode plate can be configured of an angle range of 30-60 degrees in a cross sectional view perpendicular to the lamp axis Z. The rectangular anode plate and the lead wire supporting the anode can be attached to each other in a substantially flag-shaped configuration. The invention produces a smaller discharge spot to improve thermal electron emission efficiency such that efficiency of the fluorescent lamp is improved. Furthermore, over-all size reduction of a fluorescent lamp is possible.

Fluorescent lamp having the cathode and anode with particular angular

A fluorescent lamp comprising a bulb, a fluorescent material coated on an internal surface of the bulb, a stem, a discharge chamber filled with gas and mercury, a thermal cathode filament coated with electron emitting material, lead wires passing air-tight through the stem and supporting the thermal cathode filament and an anode, where the anode is substantially rectangular with a thickness 1/16.about.3/16 of the longitudinal length of the thermal cathode filament and is substantially parallel to cathode filament in a cross-sectional view along an axis Z. The thermal cathode filament and the rectangular anode are arranged such that either the thermal cathode filament or the rectangular anode is in a rotated position relative to the other on a parallel flat surface within an angle range of 30-60 degrees. In this composition, the smaller discharge spot is obtained to improve thermal electron emission efficiency and efficiency of the fluorescent lamp. Additionally, the luminance of the fluorescent lamp does not greatly decrease and is sufficient for use even after the discharge spot passes the center point of the thermal cathode filament.

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Iwaki, Japan

Hisataka Kondo