Railroad searchlight signal with solid state illuminant and aspect indication
US5697584A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 13, 1996 |
| Grant date | Dec 16, 1997 |
| Priority date | — |
| Expiry date | May 13, 2016 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF21Y2115/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A railroad searchlight signal for producing light signals of selected colors. The searchlight uses a reflector that has an inner surface of reflective material and a focal point. One or more light emitting diodes are provided at the reflector focal point. When a current is supplied to the light emitting diode from a variable current power source, a light having a color that varies dependent upon the current is produced. The colored light produced at the light emitting diode is then directed outward of the reflector as a beam. At least one color filter that allows light of a respective color to pass therethrough is preferably provided proximate the reflector. Light that passes through the color filter is detected by a light detector such as a photovoltaic cell, a phototransistor or a photodiode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.