Textured coating for optical products

Patent metadata

Field	Value
Publication number	US-12111485-B2
Application number	US-202117332477-A
Country	US
Kind code	B2
Filing date	May 27, 2021
Priority date	Apr 25, 2014
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

A coating composition includes a first polymer and a second polymer that are incompatible and non-reactive with one another. The absolute value of the difference between the refractive index of the first polymer and the refractive index of the second polymer is about 0 to about 0.01. The first polymer and the second polymer are soluble in a carrier liquid that is a good solvent for the first polymer and a poor solvent for the second polymer. The carrier liquid is removed from the coating layer to spinodally decompose the mixture of the first polymer and the second polymer in an amount sufficient to form a substantially continuous first phase with a predominant amount of the first polymer and a substantially discontinuous second phase with a predominant amount the second polymer. At least 70% of the second phase includes droplets with an aspect ratio, when viewed in the plane of the surface of the substrate, of less than about 3.

First claim

The invention claimed is:

1. An optical element comprising:
a light transmissive substrate; and
a continuous coating on the substrate, wherein the coating comprises:
a first region comprising a first polymer selected from cellulose resins and (meth)acrylic resins; and
a second region comprising a second polymer different from the first polymer, wherein the second polymer is selected from cellulose resins and (meth)acrylic resins;

wherein the first polymer and the second polymer are incompatible and non-reactive with one another, wherein the absolute value of the difference between the refractive index of the first polymer and the refractive index of the second polymer is from about 0 to about 0.01, wherein the first regions have a thickness different from the second regions, wherein the ratio by weight of the first polymer to the second polymer is from 1:2 to 10:1, and wherein the second regions project away from a surface of the substrate to a height of about 0.1 μm to about 15 μm above the height of the first regions.

2. The optical element of claim 1 , wherein the first polymer and the second polymer comprise cellulose resins.

3. The optical element of claim 2 , wherein the first polymer and the second polymer comprise one or more of cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate.

4. The optical element of claim 3 , wherein the first polymer and the second polymer comprise one or more of cellulose acetate and cellulose acetate butyrate.

5. The optical element of claim 4 , wherein at least 35% of the regions in the coating comprise cellulose acetate butyrate.

6. The optical element of claim 1 , wherein the ratio of the first regions to the second regions in the coating is about 1:1.

7. The optical element of claim 1 , wherein the coating has an RMS roughness of about 0.01 μm to about 2.0 μm.

8. The optical element of claim 1 , wherein the bulk haze of the coating as measured after planarizing the substrate is less than about 1.0.

9. The optical element of claim 1 , wherein the wherein the absolute value of the difference between the refractive index of the first polymer and the refractive index of the second polymer is about 0 to about 0.005.

10. The optical element of claim 1 , wherein the coating has a haze of about 1% to about 99%.

11. The optical element of claim 1 , wherein the coating has a clarity of about 5% to about 98%.

12. The optical element of claim 1 , wherein the coating has a haze and a clarity both less than about 50%.

13. An optical element comprising:
a light transmissive substrate; and
a continuous coating on the substrate, wherein the coating comprises:
a first region comprising a first polymer selected from cellulose resins and (meth)acrylic resins; and
a second region comprising a second polymer different from the first polymer, wherein the second polymer is selected from cellulose resins and (meth)acrylic resins; and

a third polymer compatible with at least one of the first and the second polymers, wherein the first polymer and the second polymer are incompatible and non-reactive with one another, wherein the absolute value of the difference between the refractive index of the first polymer and the refractive index of the second polymer is from about 0 to about 0.01, and wherein the first regions have a thickness different from the second regions.

14. An optical element comprising:
a light transmissive substrate; and
a continuous coating on the substrate, wherein the coating comprises:
a first region comprising a first polymer selected from cellulose resins and (meth)acrylic resins; and
a second region comprising a second polymer different from the first polymer, wherein the second polymer is selected from cellulose resins and (meth)acrylic resins;

wherein the first polymer and the second polymer are incompatible and non-reactive with one another, wherein the absolute value of the difference between the refractive index of the first polymer and the refractive index of the second polymer is from about 0 to about 0.01, wherein the first regions have a thickness different from the second regions, wherein the ratio by weight of the first polymer to the second polymer is from 1:2 to 10:1, and wherein the effective transmission of the coating is at least 1.1.

Assignees

• 3M Innovative Properties Company

Inventors

• Ludemann Thomas J
• Hagen Jeffrey W
• Ask David T
• Gillette Kristy A
• Shockey Eric D

Classifications

• G02B27/0025

  for optical correction, e.g. distorsion, aberration · CPC title

• G02B5/021

  the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures · CPC title

• G02B1/10

  Optical coatings produced by application to, or surface treatment of, optical elements (G02B1/08 takes precedence) · CPC title

• B05D1/305

  Curtain coating · CPC title

• B05D1/28

  performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers · CPC title