# US 5,350,972 A · UV absorbing lamp glass

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- Number: US 5,350,972 A
- Document ID: US5350972A
- Status: Granted
- Kind: A
- Application number: 08/066,642
- Filed: 1993-05-25
- Granted: 1994-09-27
- Earliest claimed: 1993-05-25
- Assignees: General Electric Company
- Inventors: Gerald L. Bucher; Christopher H. Welker; Edward E. Hammer; Curtis E. Scott; Thomas F. Soules
- Web page: https://patentgrep.com/patent/US5350972A

## CPC

- C03C 3/095: containing rare earths
- A61N 5/0614: {Tanning}
- C03C 4/085: {for ultraviolet absorbing glass}
- H01J 61/302: {characterised by the material of the vessel}
- H01J 61/40: by light filters; by coloured coatings in or on the envelope
- A61N 2005/0654: {Lamps}
- A61N 2005/0667: {Filters}
- H01J 61/72: having a main light-emitting filling of easily vaporisable metal vapour, e.g. mercury
- Y10S 501/905: Ultraviolet transmitting or absorbing
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A UV absorbing soda-lime glass containing specific amounts of cerium oxide and iron oxide permits the use of significantly less CeO.sub.2 than is used in prior art glass. The amount of cerium oxide and iron oxide present is 0.02-0.07 wt. % and 0.02-0.06 wt. %, respectively, with a combined total typically no more than 0.13 wt. %. This glass is useful for fluorescent lamp envelopes in absorbing UVB radiation having a wavelength between 280-320 nm, while being transparent to visible light radiation without effecting the color of the light emitted by the lamp.

## Claims

### Claim 1

An electric arc discharge lamp having an arc discharge light source which emits both visible light radiation and UV radiation enclosed within a soda-lime glass envelope having a transmission of not more than about 25% of said UV radiation, wherein at least a portion of said UV radiation emitted has a wavelength between 280-320 nm, said soda-lime glass comprising cerium oxide, predominantly in the form of CeO.sub.2, present in an amount of from 0.02 to 0.1 wt. % of said glass composition and iron oxide, predominantly in the form of Fe.sub.2 O.sub.3, present in an amount of from 0.02 to 0.06 wt. % of said glass composition.

### Claim 2 (depends on 1)

A lamp according to claim 1 wherein the combined amount of said cerium oxide and iron oxide present in said glass ranges between 0.07-0.13 wt. % of said glass composition.

### Claim 3

A fluorescant lamp having a mercury arc discharge light source which emits UV radiation between 280-320 nm enclosed within a soda-lime glass envelope, wherein said glass comprises the following oxide composition in weight percent:
______________________________________ SiO.sub.2 65-75% Na.sub.2 O 12-20% CaO 4-6% MgO 3-4% Al.sub.2 O.sub.3 0.3-2.0% K.sub.2 O 0.3-2.0% CeO.sub.2 .02-.1% Fe.sub.2 O.sub.3 .02-.06% ______________________________________

### Claim 4 (depends on 2)

A lamp according to claim 2 wherein said cerium oxide is present in an amount of 0.02-0.07 wt. % of the glass.

### Claim 5 (depends on 3)

A glass according to claim 3 wherein the combined amount of said cerium oxide and said iron oxide in said glass is 0.07-0.13 wt. %.

### Claim 6 (depends on 4)

A glass according to claim 4 wherein said combined amount of said cerium oxide and said iron oxide present in said glass is 0.08-0.12 wt. %.