Line light source including fluorescent colorant

DETAILED DESCRIPTION The present invention provides a line light source which exhibits improved conspicuity in environments of high ambient lighting conditions.
According to one embodiment of the present invention, a line light source includes a light conduit which comprises a thin film of a totally internally reflecting material, a light source optically coupled to said light conduit for introducing light into a first end of the light conduit, and a fluorescent colorant in the light directing film.
In another embodiment of the present invention, the light conduit is preferably disposed substantially entirely within a tubular housing.
In this embodiment, either the thin film or the housing may include a fluorescent colorant.
In an alternative embodiment of the present invention, a separate thin film comprising a fluorescent colorant may be employed.
Advantageously, the fluorescent colorants increase the conspicuity of the line light source in environments of high ambient light without substantially reducing the light output of the tubes in environments of low ambient light.
In yet another embodiment of the present invention at least one of the tubular housing or the light conduit comprises a polymeric matrix, a colorant, and hindered amine light stabilizer, wherein the colorant contains at least one of the dyes selected from the group of thioxanthone, perylene imide and thioindigiod compounds and the polymeric matrix comprises polycarbonate.