JPS5519703A - Fluorescent lamp - Google Patents

Abstract

PURPOSE: To make the promotion of improvement of characteristic, with a conductive film prevented from blacking phenomenon or lighting yellowing, that is generated at the time of long time lighting, by coating to stick γ-alumina powder to the conductive film which is applied for glass tube surfaces.

CONSTITUTION: On a conductive film 2, coated on and stuck to the inner surfaces of a bulb 1, is coated a dispersed liquid of γ-alumina powder by the flow down method from top face opening part of the bulb 1, with a hot air at temperature of 80°C blown at air speed of 3 m/sec into the bulb 1, in a time of as long as three minutes is dried an alumina powder 3, on which a luminous layer 4 is layer-built. For this γ-alumina powder is used a particle of diameter, for instance, in a range of 5 to 30 millimicrons, with its coating amount made to 1.5 × 10^-2 to 6.5 × 10^-2 mg/cm² or its film thicness to 0.5 to 5 microns. In this way, the γ-alumina powder 3 becomes an insulation film to shut off the spark between EC film and mercury particle, to prevent the conductive film from blacking phenomenon or lighting yellowing caused when in the lighting for a long period, thus the characteristic can be improved.

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