JPS5450166A - Low-pressure vapor discharge lamp - Google Patents

Abstract

PURPOSE: To provide a low-pressure vapor discharge lamp, in which solid filler material is filled tightly and roughly in the discharge space defined between an inner glass tube and an outer glass bulb, such that discharge current be passed through the portion of the discharge space where the solid filler material is filled roughly, whereby it is enabled to stabilize the condition of electric discharge.

CONSTITUTION: Inner glass tube (for instance, 17cm long and having an inner diameter of 3cm) 2 is disposed coaxially in outer glass bulb (for instance, 20cm long and having a maximum diameter of 8cm) 1, and they are connected and fixed at the portion of stem 4. Fluorescent material 3 is coated on the surface of these inner and outer bulbs 2, 1. Cathode 5 of filament is supported by the stem 4, whereas a plurality of (two) anodes 6, 6' are disposed on the outside of inner tube 2 and supported by the flare of stem 4. Glass wool 7 is filled in the discharge space dieined between the outer bulb 1 and inner tube 2, such that density of the glass wool is relatively low (for instance, 10-⁶W10-⁴ at the volume ratio) at the upper portion of anodes 6, 6', whereas the density is relatively high (for instance, 10-⁴W10-³ at the volume ratio) at portions spaced circumferentially 90 degrees from the positions of the anodes 6, 6', as shown in the drawing

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