Patent · US Expired

Display lighting with matched narrow band filter and light source

US5690421A · kind A · utility

18Cited by

3References

13Claims

0Family size

Assignee

Matsushita Electric Works R&D Laboratory, Inc. · US

Inventors

Michael J. Shea · Salem, US
Jakob Maya · Brookline, US
John F. Waymouth · Marblehead, US

Key dates

Filing date	Sep 25, 1995
Grant date	Nov 25, 1997
Priority date	—
Expiry date	Sep 25, 2015

Classification

Technology area (CPC F)Mechanical Engineering; Lighting; Heating
CPC primaryF21W2111/02
WIPO fieldElectrical machinery, apparatus, energy
WIPO sectorElectrical engineering

Abstract

A narrow band light source is combined with a narrow band filter on the face of a traffic light to reduce the problem of sun glare reflected from one traffic light, reducing intensity of the sunlight glare while light from the narrow band source passes through the filter essentially unattenuated, allowing system efficiency to remain high.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.