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1. WO2006100127 - ILLUMINATING DEVICE COMBINING A WHITE LED AND A DIFFUSING SHEET

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

Claims

1. Luminous device comprising at least one white LED having a luminous flux of greater than 3 Lm, advantageously greater than 5 Lm, preferably greater than 10 Lm and even more preferably greater than 50 Lm, and a cover made of a transparent plastic in which scattering particles with a content of 0.3 to 5%, preferably 0.3 to 4%, are dispersed and having, when the LED is off, a luminosity L of less than 40, preferably less than 35, and when the LED is lit, a luminosity L of greater than 55, an a* value of between -7.5 and +7.5 and a b* value of between -7.5 and +7.5.

2. Luminous device according to Claim 1, characterized in that the transparent plastic is of the thermoplastic or thermosetting type and has a light transmission in the visible range of at least 50%, preferably at least 70% and even more preferably at least 80% according to the DIN 67-507 standard.

3. Luminous device according to either of Claims 1 and 2, characterized in that the transparent plastic is chosen from crystal polystyrene, polyethylene terephthalate, a transparent, especially clarified, polyolefin, clarified polypropylene, PMMA, a transparent polyamide or polycarbonate.

4. Luminous device according to either of Claims 1 and 2, characterized in that the transparent plastic is a methyl methacrylate homopolymer or a copolymer comprising from 80 to 99.5% by weight of methyl methacrylate and from 0.5 to 20% by weight of at least one monomer having at least one ethylenic unsaturation that can copolymerize with methyl methacrylate.

5. Luminous device according to Claim 4, characterized in that the transparent plastic is a copolymer comprising, by weight, 90 to 99.7%, preferably 90 to 99.5%, of methyl methacrylate and 0.3 to 10%, preferably 0.5 to 10%, of at least one monomer having at least one ethylenic unsaturation that can be copolymerized with methyl methacrylate.

6. Luminous device according to either of Claims 1 and 2, characterized in that the transparent plastic is a polyester obtained by the reaction of at least one carboxylic acid derivative with at least one aromatic or aliphatic diol.

7. Luminous device according to Claim 6, characterized in that the polyester is a homopoly-carbonate or a copolycarbonate based on a bisphenol of formula HO-Z-OH for which Z denotes a divalent organic radical possessing from 6 to 30 carbon atoms and containing one or more aromatic group (s).

8. Luminous device according to Claim 7, characterized in that the diphenol is chosen from dihydroxydiphenyls, bis (hydroxyphenyl ) alkanes, bis- (hydroxyphenyl) cycloalkanes, indane bisphenols, bis (hydroxyphenyl) ethers, bis (hydroxyphenyl) ketones, bis (hydroxyphenyl) sulphones, bis (hydroxyphenyl) sulphoxides and α, α' -bis (hydroxyphenyl) diisopropyl-benzenes .

9. Luminous device according to one of the preceding claims, characterized in that the scattering particles have a mean diameter of between 0.5 and 100 μm, advantageously between 1 and 80 μm and preferably between 1 and 70 μm.

10. Luminous device according to one of the preceding claims, characterized in that the difference between the refractive indices (measured according to ASTM D 542) of the scattering particles and the transparent plastic is greater than 0.02 and preferably between 0.02 and 1.

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11. Luminous device according to one of Claims 1 to 10, characterized in that the scattering particles are polyamide particles, PTFE particles, crosslinked styrene-based particles, methyl-methacrylate-based crosslinked particles or silicone particles.

12. Luminous device according to one of Claims 1 to 10, characterized in that the scattering particles are BaSO4, TiO2, ZnO, CaCO3, MgO or Al2O3 particles or hollow glass microspheres.

13. Luminous device according to Claim 12, characterized in that the mean diameter of the mineral scattering particles is between 0.5 and 15 μm, preferably between 0.5 and 10 μm.

14. Luminous device according to either of Claims 12 and 13, characterized in that the content of scattering particles is between 0.3 and 4%, preferably between 0.3 and 2%.

15. Luminous device according to one of Claims 1 to 14, characterized in that at least one of the faces of the cover has a roughness Ra of between 0.5 and 4 μm, preferably between 1 and 3 μm.

16. Use of the luminous device according to any one of Claims 1 to 15 for :
• interior lighting;
• advertising displays;
• direction lighting or escape route marking;
• illuminated signs ;
• traffic signalling; and
• automobile lighting.

17. Use according to Claim 16, characterized in that the cover has the form of a letter or a number.

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18. Use according to Claim 16, characterized in that the automobile lighting is a headlamp, a daytime light, a direction indicator, a stop light, a fog lamp or a reversing light.