Glass having antiglare surface with low display sparkle
A glass article having a low level of grainy appearance that can appear to have a shift in the pattern of the grains with changing viewing angle of a display, or “sparkle.” The glass article—which, in some embodiments, is a transparent glass sheet—has small-angle-scattering properties and/or distinctness-of-reflected-image (DOI), leading to improved viewability in display applications, especially under high ambient lighting conditions. In some embodiments, the antiglare surface of the glass sheet is an etched surface, with no foreign coating present on the antiglare surface.
1. A display system, the display system comprising:
a pixelated display having a plurality of pixels and an imaging plane; and
a transparent glass sheet having an etched glass antiglare surface, wherein the transparent glass sheet is disposed in front of the pixelated display such that the etched glass antiglare surface is distal from the pixelated display and separated from the imaging plane by an optical distance, wherein the transparent glass sheet has a pixel power deviation of less than about 7.5%, wherein the transparent glass sheet has a 20° distinctness of image of less than about 60.
2. The display system of claim 1 , wherein the transparent glass sheet has a 20° distinctness of image of less than about 40.
3. The display system of claim 1 , wherein the pixelated display alone has a second pixel power deviation, and wherein pixel power deviation of the transparent glass sheet combined with the pixelated display is less than about 4% greater than the second pixel power deviation.
4. The display system of claim 1 , wherein the pixelated display alone has a second pixel power deviation, and wherein pixel power deviation of the transparent glass sheet combined with the pixelated display is less than about two times greater than the second pixel power deviation.
5. The display system of claim 4 , wherein the pixelated display has a minimum sub-pixel window opening dimension of less than 200 μm.
6. The display system of claim 4 , wherein the optical distance between the imaging plane and the etched glass antiglare surface is in a range from about 1.0 mm to about 3.5 mm.
7. The display system of claim 1 , wherein the transparent glass sheet is strengthened.
8. The display system of claim 7 , wherein the transparent glass sheet is strengthened by ion exchange, and wherein the transparent glass sheet has at least one surface having a region under a compressive stress, the region extending from the surface to a depth of layer within the transparent glass sheet.
9. The display system of claim 8 , wherein the compressive stress is at least about 350 MPa and the depth of layer is at least 15 μm.
10. The display system of claim 1 , wherein the transparent glass sheet comprises one of a soda lime glass, an alkali aluminosilicate glass, and an alkali aluminoborosilicate glass.
11. The display system of claim 10 , wherein the glass comprises at least 2 mol % of Al 2 O 3 or ZrO 2 .
12. The display system of claim 1 , wherein the transparent glass sheet has:
a first RMS surface roughness Rlong of up to about 300 nm measured in a range of lateral spatial periods from about 40 μm to about 640 μm; and
a second RMS surface roughness Rshort measured at lateral spatial periods of less than about 20 μm, wherein the ratio (Rlong/Rshort) is less than about 3.9.
13. The display system of claim 12 , wherein the transparent glass sheet has an Rshort of at least about 30 nm.
14. The display system of claim 13 , wherein the transparent glass sheet has a transmission haze of less than about 20%.
15. The display system of claim 12 , wherein the transparent glass sheet has a third RMS roughness Rtotal, measured without surface wavelength filtering, in a range from about 60 nm to about 600 nm.
16. A glass article comprising:
a transparent glass sheet having at least one etched glass antiglare surface, wherein the etched glass antiglare surface has:
a first RMS surface roughness Rlong of up to about 300 nm measured in a range of lateral spatial periods from about 80 μm to about 640 μm; and a second RMS roughness Rtotal in a range from about 60 nm up to about 600 nm, measured without surface wavelength filtering, wherein there is a ratio Rtotal/Rlong of greater than or equal to about 2.20.
17. The glass article of claim 16 , wherein the etched glass antiglare surface has a third RMS surface roughness Rshort nm of greater than about 30 nm, wherein Rshort is measured at lateral spatial periods of less than about 20 μm.
18. The glass article of claim 16 , wherein the transparent glass sheet has a transmission haze of less than about 20%.
19. The glass article of claim 16 , wherein the transparent glass sheet has a 20° distinctness of image of less than about 60.
20. The glass article of claim 16 , wherein there is no foreign coating present on the etched glass antiglare surface.
21. The glass article of claim 16 , wherein the etched glass antiglare surface has a third RMS surface roughness Rshort, wherein Rshort is measured at lateral spatial periods of less than about 20 μm, and Rlong/Rshort is less than about 3.9.