Display lighting with matched narrow band filter and light source
AssigneeMatsushita Electric Works R&D Lab.
InventorsMichael Joseph Shea, Jakob Maya, John Francis Waymouth
Life of this patent
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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.
Claims13
Light display system comprising:
- (a) means defining a narrow band light source with FWHM of under 55 nm;
- (b) means defining an enclosure for said source and at least one viewing aperture of the enclosure;
- (c) means defining a filter in operative relation to the aperture to pass high intensity light (relative to light source (a)) from a source outside the enclosure to within the enclosure and to intercept light re-emerging from the enclosure and in each pass of entering and re-emergent light filtering the entering and re-emergent light to substantially block spectral portions thereof that are not within the narrow band of said light source (a) but to pass spectral portions that are within said narrow band.
Light display system comprising (1) light source means, and (2) color filter means for selective display of a color corresponding to the filter, for use in an environment exposed to strong glare generating wide band ambient light, the improvement wherein the light source and filter are selected for a common narrow band range, substantially narrower than the said ambient source and with essentially common peaks.
Dependencies are inferred from the claim text.