Measurement of fill gas pressure in light bulbs
US4452071A · kind A · utility
6Cited by
3References
3Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 22, 1982 |
| Grant date | Jun 5, 1984 |
| Priority date | — |
| Expiry date | Nov 22, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/02872
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Tungsten halogen lamps require a fill pressure of several atmospheres. To verify the fill pressure at the time of manufacture the pressure is indirectly measured by first measuring the speed of sound within the lamp. A shock wave is produced within the lamp by rapidly heating a lamp filament or producing an arc between two adjacent filaments and measuring the time required for the shock wave to sequentially disturb two spaced light beams passing through the lamp. The speed of sound is determined from the measured time and the pressure is calculated from the speed of sound.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.