Engineered antiglare surface to reduce display sparkle

Patent metadata

Field	Value
Publication number	US-10613340-B2
Application number	US-201615358880-A
Country	US
Kind code	B2
Filing date	Nov 22, 2016
Priority date	May 27, 2011
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A transparent substrate having an antiglare surface with reduced display sparkle. The transparent substrate has a roughened antiglare surface and a diffraction element below the antiglare surface. The diffraction element reduces sparkle by filling gaps between sub-pixels in a pixelated display with orders of diffraction. A display system comprising the transparent substrate and a pixelated display is also provided.

First claim

The invention claimed is:

1. A transparent substrate comprising an antiglare surface and a diffraction element having a grating period disposed below the antiglare surface, wherein:
the transparent substrate, when disposed in front of a pixelated display, reduces an inter-pixel gap in the pixelated display to less than about one third the length or width of a pixel present in the pixelated display,
the transparent substrate is separated from the pixelated display by a predetermined distance, and
the grating period is determined at least based on the predetermined distance and the size of the inter-pixel gap.

2. The transparent substrate of claim 1 , wherein the diffraction element is disposed on a second surface of the substrate, the second surface being opposite the antiglare surface.

3. The transparent substrate of claim 2 , wherein the diffraction element is integral to the second surface.

4. The transparent substrate of claim 2 , wherein the diffraction element has a first refractive index and the second surface is in contact with an epoxy layer having a second refractive index that is different from the first refractive index.

5. The transparent substrate of claim 1 , wherein the periodic grating has a grating period T and diffraction order k, wherein the periodic grating is separated from a pixel by optical distance D, the pixel emitting light having a wavelength λ, and wherein k·D·λ/Pitch<T<2k·D·λ/Pitch.

6. The transparent substrate of claim 5 , wherein the grating period T is obtained by solving for the equation dx=D·tan(θ), where θ=λ/T and θ is the diffraction angle, when dx is equal to one third of the size of a pixel present in the pixelated display.

7. The transparent substrate of claim 1 , wherein the diffraction element is disposed on a polymeric film which is disposed on the second surface.

8. The transparent substrate of claim 1 , wherein the transparent substrate has a second surface opposite the antiglare surface and a bulk portion between the antiglare surface and the second surface, and wherein the diffraction element is disposed in the bulk portion.

9. The transparent substrate of claim 1 , wherein the antiglare surface is a roughened surface, having a total RMS roughness Rtotal, measured without surface wavelength filtering, in a range from about 60 nm to about 600 nm.

10. The transparent substrate of claim 9 , wherein the roughened surface has a first RMS surface roughness Rlong, measured in a range of lateral spatial periods from about 40 μm to about 640 μm, of up to about 300 nm; 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.

11. The transparent substrate of claim 1 , wherein the transparent substrate has a transmission haze of less than about 20%.

12. The transparent substrate of claim 1 , wherein the transparent substrate has a 20° distinctness of image of less than about 85.

13. The transparent substrate of claim 1 , wherein the transparent substrate comprises a sheet of polymeric material.

14. The transparent substrate of claim 1 , wherein the transparent substrate comprises a glass sheet.

15. The transparent substrate of claim 14 , wherein the glass sheet is strengthened.

16. The transparent substrate of claim 14 , wherein the glass sheet is strengthened by ion exchange, and wherein the 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 substrate.

17. The transparent substrate of claim 14 , wherein the compressive stress is at least about 350 MPa and the depth of layer is at least 15 μm.

18. The transparent substrate of claim 14 , wherein the glass sheet comprises one of a soda lime glass, an alkali aluminosilicate glass, and an alkali aluminoborosilicate glass.

19. The transparent substrate of claim 18 , wherein the glass comprises at least 2 mol % of Al 2 O 3 or ZrO 2 .

20. The transparent substrate of claim 1 , wherein the antiglare surface comprises a roughened surface portion having an RMS amplitude of at least about 80 nm, and an unroughened surface portion, wherein the unroughened surface portion forms a fraction of the antiglare surface of up to about 0.1, and wherein the roughened surface portion forms a remaining fraction of the antiglare surface.

21. The transparent substrate of claim 1 , wherein a plurality of pixels, each of the plurality of pixels having a pixel size, when viewed through the transparent substrate, has a gap between adjacent pixels of less than two thirds of the pixel size.

22. The transparent substrate if claim 1 , wherein the transparent substrate has a pixel power deviation of less than about 7.5% when disposed in front of the pixelated display, the pixelated display having a plurality of pixels and an imaging plane, such that the antiglare surface is distal from the pixelated display and separated from the imaging plane by a predetermined distance.

23. The transparent substrate of claim 22 , wherein the transparent substrate has a 20° distinctness of image of less than about 80.

24. The transparent substrate of claim 22 , wherein the pixelated display alone has a second pixel power deviation, and wherein pixel power deviation of the transparent substrate combined with the pixelated display is less than about 4% greater than the second pixel power deviation.

25. The transparent substrate of claim 22 , wherein the pixelated display alone has a second pixel power deviation, and wherein pixel power deviation of the transparent substrate combined with the pixelated display is less than about two times greater than the second pixel power deviation.

Assignees

• Corning Inc

Inventors

• Borrelli Nicholas Francis
• Gollier Jacques
• Kosik Williams Ellen Marie
• West James Andrew

Classifications

• G02B27/4205 Primary

  having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant · CPC title

• G02B5/0221

  the surface having an irregular structure (G02B5/0226 takes precedence) · CPC title

• G02F1/133502

  Antiglare, refractive index matching layers · CPC title

• G02B5/0278

  used in transmission · CPC title

• G02F2203/03

  scattering · CPC title