Battery-powered flashing superluminescent light emitting diode safety warning light
US5313187A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 6, 1990 |
| Grant date | May 17, 1994 |
| Priority date | — |
| Expiry date | Sep 6, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S362/80
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
One or more superluminescent light emitting diodes (SLDS) are driven with an oscillatory square wave pulse drive signal Vd varying between OVDC and 1.8-3.2VDC at a frequency between 1Hz to 12Hz, preferably between 6Hz to 8Hz, and having a pulse duty cycle between 5% to 10%, preferably between 6% to 8%, to periodically forward bias the SLDs into illumination and produce a brilliant rapidly flashing light having high on-off contrast for enhanced visibility and perceptibility at a distance, thus being usable for battery-powered visual indicator and warning flasher applications. A low frequency oscillator stage generates an oscillatory square wave voltage signal Vo which drives a power driver stage to produce the correspondingly oscillating drive voltage signal Vd which is supplied to the SLDS. The frequency and duty cycle of the drive pulse signal Vd are chosen to produce enhanced SLD illumination brightness for high on-off contrast and to operate the SLD within its most efficient operating characteristics for long battery life. An exemplary circuit utilizes an asatable monovibrator employing two transistors operated in the saturation mode with positive feedback as the low frequency o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.