Double oscillator battery powered flashing superluminescent light emitting diode safety warning light
US5175528A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1991 |
| Grant date | Dec 29, 1992 |
| Priority date | — |
| Expiry date | Aug 5, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S362/80
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A flashing safety warning light in which a superluminescent light-emitting diode (SLD) light source is driven by an oscillatory drive signal at a visually imperceptible but highly efficient operating frequency, the oscillatory drive signal preferably being a pulse signal of 1 to 5 KHz to cause the SLD to be illuminated and extinguished at the oscillatory drive signal frequency, such that extinction of the SLD is not visually perceptible. The oscillatory drive signal is in turn gated on and off in accordance with a gating signal at a low, highly visually perceptible frequency in the range of 3 to 12 Hz with a pulse duty cycle of between 10 to 60% in order to cause the SLD to be visually perceived as flashing on and off at the gating signal frequency in an attention-getting manner. An implementation of the flashing safety warning light for use as a bicycle safety flasher is described, and offers enhanced warning visibility with extended battery life.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.