Automotive headlamps with improved beam chromaticity
View Patent ↗Lenses for lamps can improve the quality of the light emitted through lens by interacting with the light bulb. Photoluminescent dyes as well as non-photoluminescent dyes may be incorporated into a polycarbonate lens in order to shift the chromaticity of the light source. Further, design features such as grooves or protrusions may be incorporated into the lens to allow light produced by the photoluminescent material to escape the lens and be added to the emitted beam to further shift the chromaticity. The emitted beam is of a legal color and intensity as defined per the SAEJ578 and SAEJ1383 standards. The lighting performance may also be improved in such manner as reducing discomfort glare, increasing brightness or producing a beam that enhances road visibility at night to the human eye.
1. A lens having a molded body having a generally concave outer surface, a generally flat or convex inner surface and an edge surface where, the molded body is formed from a composition comprising polycarbonate and a photoluminescent material, wherein the lens has grooves or protrusions formed on the inner surface, such that light that interacts with the photoluminescent material within the lens can escape from the lens through the grooves or protrusions.
2. The lens of claim 1 , wherein the photoluminescent material comprises an organic fluorescent dye.
3. The lens of claim 2 , wherein the lens material further comprises a non-fluorescent dye.
4. The lens of claim 3 , wherein the fluorescent dye is included at a concentration of 0.0001 to 1 weight % of fluorescent dye and the non-fluorescent dye is included at a concentration of 0.00001 to 0.1 weight % of non-fluorescent dye.
5. The lens of claim 3 , wherein the fluorescent dye is included at a concentration of 0.005 to 0.5 weight % of fluorescent dye and the non-fluorescent dye is included at a concentration of 0.0001 to 0.01 weight % of non-fluorescent dye.
6. The lens of claim 3 , wherein the fluorescent dye is included at a concentration of 0.01 and 0.25 weight % of fluorescent dye and the non-fluorescent dye is included at a concentration of 0.001 and 0.01 weight % of non-fluorescent dye.
7. The lens of claim 2 , wherein the fluorescent dye produces a visual effect at an edge of the lens.
8. The lens of claim 2 , wherein the fluorescent dye is selected from the group consisting of perylene derivatives, anthracene derivatives, benzoxazole derivatives, stilbene derivatives, benzoxazole derivatives, stillbene derivatives, indigoid and thioindigoid derivatives, imidazole derivatives, naphtalimide derivatives, xanthenes, thioxanthenes, coumarins, rhodamines, (2,5-bis[5-tert-butyl-2-benzoxazolyl]thiophene) and derivatives thereof.
9. The lens of claim 1 , wherein the lens further comprises an edge reflector, wherein the edge reflector covers at least a portion of the edge, whereby light conducted within the lens that reaches the edge is reflected back into the lens.
10. The lens of claim 9 , wherein the photoluminescent material comprises an organic fluorescent dye.
11. The lens of claim 10 , wherein the lens material further comprises a non-fluorescent dye.
12. The lens of claim 11 , wherein the fluorescent dye is included at a concentration of 0.0001 to 1 weight % of fluorescent dye and the non-fluorescent dye is included at a concentration of 0.00001 to 0.1 weight % of non-fluorescent dye.
13. The lens of claim 11 , wherein the fluorescent dye is included at a concentration of 0.005 to 0.5 weight % of fluorescent dye and the non-fluorescent dye is included at a concentration of 0.0001 to 0.01 weight % of non-fluorescent dye.
14. The lens of claim 11 , wherein the fluorescent dye is included at a concentration of 0.01 and 0.25 weight % of fluorescent dye and the non-fluorescent dye is included at a concentration of 0.001 and 0.01 weight % of non-fluorescent dye.
15. The lens of claim 10 wherein the fluorescent dye produces a visual effect at an edge of the lens.
16. The lens of claim 10 wherein the fluorescent dye is selected from the group consisting of perylene derivatives, anthracene derivatives, benzoxazole derivatives, stilbene derivatives, benzoxazole derivatives, stillbene derivatives, indigoid and thioindigoid derivatives, imidazole derivatives, naphtalimide derivatives, xanthenes, thioxanthenes, coumarins, rhodamines, (2,5-bis[5-tert-butyl-2-benzoxazolyl]thiophene) and derivatives thereof.