# US 5,705,887 A · Fluorescent lamp with end of life arc quenching structure

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- Number: US 5,705,887 A
- Document ID: US5705887A
- Status: Granted
- Kind: A
- Application number: 08/615,406
- Filed: 1996-03-14
- Granted: 1998-01-06
- Earliest claimed: 1995-02-17
- Assignees: Osram Sylvania Inc.
- Inventors: John W. Shaffer
- Web page: https://patentgrep.com/patent/US5705887A

## CPC

- H01J 61/02: Details
- H01J 61/24: Means for obtaining or maintaining the desired pressure within the vessel
- H01J 61/302: {characterised by the material of the vessel}
- H01J 61/70: Lamps with low-pressure unconstricted discharge {having a cold pressure < 400 Torr}
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

A fluorescent lamp is disclosed containing a deposit of a dried metal hydride-containing paste. The dried metal hydride-containing paste has a decomposition temperature higher than the temperature present during normal lamp operation. At the end of the lamp life, an increase in lamp temperature decomposes the metal hydride-containing paste and releases hydrogen within the lamp. The presence of hydrogen causes the lamp to extinguish passively without significant end heating or glass cracking.

## Claims

### Claim 1

A fluorescent lamp comprising:
a glass tube;
an electrode at each end of said tube; each of said electrodes comprising a pair of lead wires extending through a glass bead and joined to a coil; and
a deposit of dried metal hydride-containing paste disposed on said glass bead, said deposit having a decomposition temperature higher than temperatures within said tube during normal operation of said lamp.

### Claim 2 (depends on 1)

The fluorescent lamp in accordance with claim 1 wherein said deposit is disposed on said glass bead at the juncture of said glass bead and said lead wires extending therefrom.

### Claim 3 (depends on 1)

The fluorescent lamp in accordance with claim 1 wherein said deposit comprises a single deposit extending between and surrounding said pair of lead wires adjacent to a surface of said glass bead.

### Claim 4 (depends on 1)

The fluorescent lamp in accordance with claim 1 wherein said deposit comprises two discrete portions separated by a gap.

### Claim 5 (depends on 1)

The fluorescent lamp in accordance with claim 1 wherein said deposit is disposed on a surface of said glass bead nearest said electrode.

### Claim 6 (depends on 1)

The fluorescent lamp in accordance with claim 1 wherein said metal hydride contained in said paste is a selected one from a group consisting of titanium, zirconium, hafnium, a titanium-zirconium alloy, a titanium hafnium alloy, and a zirconium-hafnium alloy.

### Claim 7 (depends on 1)

The fluorescent lamp in accordance with claim 1 wherein said metal hydride comprises an alloy consisting of a selected one from a group consisting of titanium, zirconium, and hafnium, and a selected one from a group consisting of cobalt, iron, nickel, manganese, and lanthanum.

### Claim 8 (depends on 1)

The fluorescent lamp in accordance with claim 1 wherein said metal hydride comprises titanium hydride.

### Claim 9

A fluorescent lamp comprising:
a glass tube;
an electrode at each end of said tube; each of said electrodes comprising a pair of lead wires extending through a glass seal at an end of said tube and joined to a coil; and
a deposit of dried metal hydride-containing paste disposed on said glass seal, said deposit having a decomposition temperature higher than temperatures within said tube during normal operation of said lamp.

### Claim 10 (depends on 9)

The fluorescent lamp in accordance with claim 9 wherein said deposit is disposed on said glass seal at the juncture of said glass seal and said lead wires extending therefrom.

### Claim 11 (depends on 9)

The fluorescent lamp in accordance with claim 9 wherein said metal hydride contained in said paste is a selected one from a group consisting of titanium, zirconium, hafnium, a titanium-zirconium alloy, a titanium hafnium alloy, and a zirconium-hafnium alloy.

### Claim 12 (depends on 9)

The fluorescent lamp in accordance with claim 9 wherein said metal hydride comprises an alloy consisting of a selected one from a group consisting of titanium, zirconium, and hafnium, and a selected one from a group consisting of cobalt, iron, nickel, manganese, and lanthanum.

### Claim 13 (depends on 9)

The fluorescent lamp in accordance with claim 9 wherein said metal hydride comprises titanium hydride.