Incandescent lamp

Abstract

By adding the afterglow function to the incandescent lamp, it is made easier, in the place where the incandescent lamp is used, to recognize objects nearby in the darkness after the lamp is turned off or when the electrical power is cut off. An incandescent lamp wherein an inner surface of a glass globe is coated with a phosphorescent phosphor is provided. For the phosphorescent phosphor, there can be used a phosphorescent phosphor comprising, as a host crystal, a compound of the general formula either MAl2O4 or MAl14O25 wherein M is one or more of metal elements selected from the group consisting of calcium, strontium and barium, and utilizing europium (Eu) as an activator, together with dysprosium (Dy) or neodymium (Nd) as a coactivator; as well as a phosphorescent phosphor comprising Y2O2S as a host crystal, and utilizing europium (Eu), magnesium (Mg) or titanium (Ti) as an activator.

Description

technical field [0001] The present invention relates to incandescent lamps widely used for general lighting, and more particularly to incandescent lamps with an afterglow function additionally provided by an inner coating of the surface of a glass sphere with a phosphorescent phosphor. Background technique [0002] Existing incandescent lamps widely used for general lighting have a structure in which a stem carrying a pair of wires is sealed at the end of a bulb made of soft glass, a coiled filament of tungsten is placed between these wires, and such as An inert gas such as argon is sealed inside the glass bulb. [0003] For existing incandescent lamps, either a clear glass bulb with nothing stuck inside it or a diffuse layer made of very fine particles of metal oxides such as silica formed on its inner surface to reduce glare glass ball. However, since no means are provided on the inner / outer surfaces of the incandescent lamp to emit light after the lamp is extinguished, ...

AI Technical Summary

Problems solved by technology

When the coating of the existing phosphorescent phosphor is applied on the inner surface of the incandescent lamp (the inner surface of the glass bulb), the phosphor layer is easily peeled off by a slight physical impact, etc.

Also, phosphorescent phosphors in incandescent lamps are more prone to degradation than phosphorescent phosphors in fluorescent lamps because the phosphor and the entire interior surface of the incandescent lamp are heated by the filament when the lamp is turned on.

This degradation of the phosphorescent phosphor reduces afterglow output and causes discoloration of the phosphorescent phosphor which tends to cause a drop in light output from the incandescent lamp itself.

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