Ultraminiature broadband light source and method of manufacturing same

US7755292B1 · kind B1 · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Margaret L. Tuma · Strongsville, US
• Joseph S. Collura · Auburn, US
• Henry Helvajian · Pasadena, US
• Michael D. Pocha · Livermore, US
• Glenn A. Meyer · Danville, US
• Charles F. McConaghy · Livermore, US
• Barry L. Olsen · Oakdale, US
• William W. Hansen · Lakewood, US

Key dates

• Filing date: Jan 22, 2007
• Grant date: Jul 13, 2010
• Expiry date: Aug 14, 2028

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01K7/00
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

An ultraminiature light source using a double-spiral shaped tungsten filament includes end contact portions which are separated to allow for radial and length-wise unwinding of the spiral. The double-spiral filament is spaced relatively far apart at the end portions thereof so that contact between portions of the filament upon expansion is avoided. The light source is made by fabricating a double-spiral ultraminiature tungsten filament from tungsten foil and housing the filament in a ceramic package having a reflective bottom and a well wherein the filament is suspended. A vacuum furnace brazing process attaches the filament to contacts of the ceramic package. Finally, a cover with a transparent window is attached onto the top of the ceramic package by solder reflow in a second vacuum furnace process to form a complete hermetically sealed package.