Ultraminiature broadband light source with spiral shaped filament

US8264134B2 · kind B2 · 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: Jun 7, 2010
• Grant date: Sep 11, 2012
• Expiry date: Jun 7, 2030

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.