Diffusing coating
The invention relates the field of light boxes, and more specifically to a diffusing layer intended to be deposited on a substrate for making a light source homogeneous. The diffusing layer according to the invention consists of agglomerated semitransparent mineral particles in a mineral binder and is characterized by the particles having a mean diameter of between 0.3 and 2 microns, the binder being in a proportion of between 10 and 40% by volume, the particles forming aggregates whose size is between 0.5 and 20 microns, preferably less than 5 microns, and the layer having a contrast attenuation of greater than 40%. The invention also relates to uses for the production of flat lamps.
1. A diffusing layer comprising, (i) semitransparent mineral particles which have a mean diameter of between 0.3 and 2 microns and (ii) a mineral binder in an amount of between 10 and 40 % by volume of said diffusing layer, wherein said semitransparent mineral particles form aggregates whose size is between 0.5 and 20 microns, and said diffusing layer has a contrast attenuation of greater than 40%.
2. The diffusing layer of claim 1 , wherein the size of said aggregates is less than 5 microns.
3. The diffusing layer of claim 1 , wherein said diffusing layer has a light transmission, T L of greater than 45%.
4. The diffusing layer of claim 3 , wherein said light transmission, T L , is greater than 60%.
5. The diffusing layer of claim 1 , wherein said semitransparent mineral particles are oxide, nitride or carbide particles.
6. The diffusing layer of claim 1 , wherein said semitransparent mineral particles comprise silicon oxide, aluminum oxide, zirconium oxide, titanium oxide, cerium oxide, or mixtures thereof.
7. The diffusing layer of claim 1 , further comprising a dispersing additive selected from the group consisting of an acid, a base, divalent ions and ionic polymers of molecular mass less than 50,000 g/mol.
8. The diffusing layer of claim 1 , wherein said diffusing layer has a thickness of between 1 and 20 microns.
9. The diffusing layer of claim 1 , wherein said mineral binder is selected from the group consisting of one or more potassium silicates, one or more sodium silicates, and one or more lithium silicates.
10. A flat lamp comprising said diffusing layer of claim 1 .
11. A flat lamp comprising a glass substrate coated with said diffusing layer of claim 1 .
12. A method of producing a component for improving the homogeneity of light in a light box comprising:
(i) providing a substrate; and
(ii) depositing said diffusing layer of claim 1 on said substrate.
13. The method of claim 12 , wherein said depositing is screen printing, coating with a paint, dip coating, spin coating, flow coating, or spraying.
14. The diffusing layer of claim 1 , wherein the semitransparent mineral particles are zirconia particles and the binder comprises a lithium polysilicate.
15. The diffusing layer of claim 1 , wherein the semitransparent mineral particles are alumina particles;
the mineral binder comprises a lithium silicate; and
the diffusing layer further comprises a polyacrylic acid dispersion-inducing additive.
16. The light diffusing layer of claim 1 , wherein the diffusing layer consists of the semitransparent mineral particles and the mineral binder and the semitransparent mineral particles are present in an amount of from 60 to 90% by volume of the diffusing layer.
17. The diffusing layer of claim 1 , having a light transmission under illuminate D 65 of from 45% to 76%.
18. The diffusing layer of claim 1 , wherein the light transmission with an illuminate D 65 is from 45% to 66%.