Transparent optical article having a colorless appearance
View Patent ↗The present invention relates to a transparent optical article comprising at least one dye at least partially inhibiting light having a wavelength ranging from 400 to 460 nm and at least one selective optical brightener that emits light by fluorescence at a wavelength ranging from 400 to 460 nm. The optical brightener acts as a means for at least partially balancing the color imparted to the transparent optical article by the dye, thus allowing for perception of said optical article as less yellow, and even colorless to an user or an observer.
1. A transparent optical lens comprising:
at least one dye A at least partially inhibiting light transmission for at least one wavelength ranging from 400 to 460 nm; and
at least one optical brightener B for at least partially balancing the color imparted to the transparent optical lens by the dye A, wherein the at least one optical brightener B emits light by fluorescence at at least one wavelength ranging from 400 to 460 nm, and wherein the dye A and the optical brightener B are different from each other;
wherein the transparent optical lens has an absolute value of difference between a maximal absorption value λmax (A) of dye A and a maximal fluorescence emission value λmax (B) of the optical brightener B that is lower than 15 nm.
2. The transparent optical lens of claim 1 , further defined as comprising a substrate having a weight and at least one layer coated on the substrate, wherein the at least one dye A and the at least one optical brightener B are incorporated into the substrate and/or into the at least one layer coated on the substrate, together or separately.
3. The transparent optical lens of claim 1 , wherein the dye A at least partially inhibits light transmission for at least one wavelength ranging from 420 to 450 nm.
4. The transparent optical lens of claim 1 , wherein the optical brightener B emits light by fluorescence at at least one wavelength ranging from 420 to 450 nm.
5. The transparent optical lens of claim 1 , further defined as having a relative light transmission factor in the visible spectrum Tv higher than 80%.
6. The transparent optical lens of claim 1 , wherein the dye A is a member of one of the perylene, coumarin, porphyrin, acridine, indolenin, and/or indol-2-ylidene families.
7. The transparent optical lens of claim 1 , wherein the optical brightener B is one of a stilbene, carbostyril, coumarin, 1,3-diphenyl-2-pyrazoline, naphthalimide, or benzoxazole.
8. The transparent optical lens of claim 1 , wherein the optical brightener B is one of a bis-benzoxazole, phenylcoumarin, methylcoumarin, or bis-(styryl)biphenyl.
9. The transparent optical lens of claim 1 , wherein the at least one dye A inhibits from 1 to 50% of light transmission for at least one wavelength ranging from 420 to 450 nm.
10. The transparent optical lens of claim 2 , wherein the dye A is incorporated into the substrate in an amount lower than 50 ppm relative to the weight of the substrate.
11. The transparent optical lens of claim 10 , wherein the dye A is incorporated into the substrate in an amount lower than 5 ppm relative to the weight of the substrate.
12. The transparent optical lens of claim 2 , wherein the dye A is incorporated into at least one layer coated on the substrate in an amount lower than 5000 ppm relative to the weight of the layer.
13. The transparent optical lens of claim 12 , wherein the dye A is incorporated into at least one layer coated on the substrate in an amount lower than 500 ppm relative to the weight of the layer.
14. The transparent optical lens of claim 2 , wherein the optical brightener B is incorporated into the substrate in an amount lower than 200 ppm relative to the weight of the substrate.
15. The transparent optical lens of claim 2 , wherein the optical brightener B is incorporated into at least one layer coated on the substrate in an amount lower than 200 ppm relative to the weight of the layer.
16. The transparent optical lens of claim 1 , further defined as having a yellowness index Yi lower than 10.
17. The transparent optical lens of claim 16 , further defined as having a yellowness index Yi lower than 5.
18. The transparent optical lens of claim 1 , further defined as having a whiteness index Wi higher than 40.
19. The transparent optical lens of claim 1 , further defined as an ophthalmic lens.