Automotive headlamps with improved beam chromaticity

• US 7,278,762 B2
• Filed: 11/16/2005
• Issued: 10/09/2007
• Est. Priority Date: 04/05/2002
• Status: Expired due to Term

• Current Assignee: SABIC Global Technologies BV (Government of Saudi Arabia)
• Original Assignee: General Electric Company
• Inventors: Terburg, Bart, Bryce, David S, Schottland, Phillipe
• Primary Examiner(s): O'Shea; Sandra
• Assistant Examiner(s): Cranson, Jr.; James W
• Application Number:
  US11/281,549
• Publication Number:
  US 20060077680A1
• Time in Patent Office: 692 Days
• Field of Search: 362/326, 362/629, 362/510, 362/509, 359/642
• US Class Current: 362/326
• CPC Class Codes: F21S 41/00 Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps reversing lights F21S43/00
• CPC Class Codes: F21S 41/162 Incandescent light sources, e.g. filament or halogen lamps
• CPC Class Codes: F21S 41/17 Discharge light sources
• CPC Class Codes: F21S 41/172 High-intensity discharge light sources
• CPC Class Codes: F21S 41/176 Light sources where the light is generated by photoluminescent material spaced from a primary light generating element
• CPC Class Codes: F21S 41/25 Projection lenses
• CPC Class Codes: F21S 41/26 Elongated lenses
• CPC Class Codes: F21S 41/28 Cover glass
• CPC Class Codes: F21S 41/285 Refractors, transparent cover plates, light guides or filters not provided in groups F21S41/24-F21S41/28
• CPC Class Codes: F21S 41/321 the reflector being a surface of revolution or a planar surface, e.g. truncated
• CPC Class Codes: F21S 45/10 Protection of lighting devices cooling of lighting devices F21S45/40; waterproofing of lighting devices F21S45/50
• CPC Class Codes: F21V 13/08 the elements being filters or photoluminescent elements and reflectors
• CPC Class Codes: F21V 3/04 characterised by materials, surface treatments or coatings
• CPC Class Codes: F21V 5/10 comprising photoluminescent material
• CPC Class Codes: F21V 9/06 for filtering out ultraviolet radiation
• CPC Class Codes: F21V 9/08 for producing coloured light, e.g. monochromatic; for reducing intensity of light with provision for controlling the colour F21V9/40
• CPC Class Codes: F21V 9/32 characterised by the arrangement of the photoluminescent material
• CPC Class Codes: F21W 2102/13 for high-beam region or low-beam region
• CPC Class Codes: F21W 2107/00 Use or application of lighting devices on or in particular types of vehicles

Abstract

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.

Claims

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.