Textured surfaces for display applications
A substrate with a textured surface is disclosed. The substrate may be, for example, a light emitter comprising a light guide, for example a backlight element for use in a display device, wherein a surface of the light guide, for example a glass substrate, is configured to have a textured surface with a predetermined RMS roughness and a predetermined correlation length of the texture. A plurality of light scatter suppressing features can be provided on the textured surface. Textured surfaces disclosed herein may be effective to reduce electrostatic charging of the substrate surface. Methods of producing the textured surface are also disclosed.
1. A substrate comprising at least one textured major surface comprising an RMS roughness R q where 5 nm≤Rq≤75 nm, the texture of the textured major surface including a correlation length T where 0 nm<T≤150 nm, the substrate further comprising a haze value equal to or less than 6.0% and a transmittance normal to the at least one major surface greater than 90% over a wavelength range from 400 nm to 700 nm.
2. The substrate according to claim 1 , wherein the substrate comprises a glass layer.
3. The substrate according to claim 2 , wherein the substrate comprises a polymer layer disposed on the glass layer.
4. The substrate according to claim 3 , wherein the textured major surface is a surface of the polymer layer.
5. The substrate according to claim 1 , wherein the substrate comprises a first substrate and further comprising a second substrate joined to the first substrate to form a substrate assembly such that the textured surface is positioned within an interior of the substrate assembly.
6. The substrate according to claim 1 , wherein the substrate is a chemically strengthened substrate.
7. The substrate according to claim 1 , wherein the substrate is a laminated substrate comprising a first glass layer including a first coefficient of thermal expansion and a second glass layer fused to the first glass layer and comprising a second coefficient of thermal expansion different from the first coefficient of thermal expansion.
8. The substrate according to claim 3 , wherein the polymer layer comprises a plurality of discrete light scatter suppressing features, the discrete light scatter suppressing features comprising an index of refraction substantially equal to an index of refraction of the glass layer.
9. The substrate according to claim 8 , wherein a spatial density of the plurality of light scatter suppressing features varies as a function of distance from an edge of the substrate.
10. The substrate according to claim 4 , wherein the polymer layer is a continuous polymer layer.
11. The substrate according to claim 10 , wherein the continuous polymer layer is a polymer film applied to the glass layer.
12. The substrate according to claim 5 , wherein the second substrate is a chemically strengthened substrate.
13. The substrate according to claim 5 , wherein the second substrate is a laminated substrate comprising a first layer including a first coefficient of thermal expansion and a second layer comprising a second coefficient of thermal expansion different from the first coefficient of thermal expansion.
14. The substrate according to claim 13 , wherein the first and second layers comprise glass.
15. The substrate according to claim 1 , wherein the substrate comprises a scatter ratio defined as a diffuse transmittance divided by a total transmittance equal to or greater than 0.5.
16. The substrate according to claim 1 , wherein the substrate comprises an optical attenuation equal to or less than 26 dB/meter in a wavelength range from 400 nm to 700 nm.
17. The substrate according to claim 1 , wherein the substrate comprises a light guide.
18. The substrate according to claim 1 , further comprising a light source positioned adjacent an edge surface of the substrate.
19. The substrate according to claim 18 , wherein the light source comprises a plurality of light sources.
20. The substrate according to claim 1 , wherein the substrate further comprises a frame disposed about a perimeter of the substrate.
21. A light guide comprising a substrate including at least one textured major surface comprising an RMS roughness R q where 5 nm≤Rq≤75 nm, the texture of the textured major surface including a correlation length T where 0 nm<T≤150 nm, the light guide further comprising a haze value equal to or less than 6.0% and a transmittance normal to the at least one major surface greater than 90% over a wavelength range from 400 nm to 700 nm.
22. The light guide according to claim 21 , wherein 5 nm≤R q ≤40 nm.
23. The light guide according to claim 22 , wherein 0 nm<T≤100 nm.
24. The light guide according to claim 21 , wherein a transmittance of the light guide normal to the at least one major surface is equal to or greater than 94%.
25. The light guide according to claim 21 , wherein the light guide has a haze value equal to or less than 6.0%.
26. The light guide according to claim 21 , further comprising a plurality of light scatter suppressing features deposited on the textured major surface.
27. The light guide according to claim 26 , wherein a spatial density of the plurality of light scatter suppressing features varies as a function of distance from an edge of the substrate.
28. The light guide according to claim 21 , wherein the substrate is a glass substrate.