Article of manufacture with micro-features of differing surface roughness

1. An article of manufacture, comprising:

a substrate having a major surface;

a plurality of distinct first micro-features of well-defined shape at the major surface of the substrate, each of the first micro-features embodied as a three-dimensional feature recessed into or protruding from the major surface and having a distinct surface on a scale larger than the surface roughness of the surface of the first micro-feature, the surface of the respective first micro-features having a low surface roughness; and

a plurality of distinct second micro-features of well-defined shape at the major surface of the substrate, each of the second micro-features embodied as a three-dimensional feature recessed into or protruding from the major surface and having a distinct surface on a scale larger than the surface roughness of the surface of the second micro-feature, the surface of the respective second micro-features comprising a high surface roughness substantially greater than the low surface roughness,

wherein the surface of each of the second micro-features is a first surface and each of the second micro-features additionally comprises a second surface that comes together with the first surface to form a ridge having ends that intersect the major surface, the first surface and the second surface each having the high surface roughness.

2. The article of manufacture of claim 1 , wherein the high surface roughness is an average surface roughness ranging from about 1 μm to about 5 μm and the low surface roughness is an average surface roughness less than about 0.10 μm.

3. An article of manufacture, comprising:

a substrate having a major surface;

a plurality of distinct first micro-features of well-defined shape at the major surface of the substrate, each of the first micro-features embodied as a three-dimensional feature recessed into or protruding from the major surface and having a distinct surface on a scale larger than the surface roughness of the surface of the first micro-feature, the surface of the respective first micro-features having a low surface roughness; and

a plurality of distinct second micro-features of well-defined shape at the major surface of the substrate, each of the second micro-features embodied as a three-dimensional feature recessed into or protruding from the major surface and having a distinct surface on a scale larger than the surface roughness of the surface of the second micro-feature, the surface of the respective second micro-features comprising a high surface roughness substantially greater than the low surface roughness,

wherein the surface of each of the second micro-features is a first surface and each of the second micro-features additionally comprises a second surface that comes together with the first surface to form a ridge having ends that intersect the major surface, the first surface having the high surface roughness and the second surface having a low surface roughness less than the high surface roughness.

4. The article of manufacture of claim 1 , wherein:

the first micro-features and the second micro-features are present together at a first region of the major surface near an edge of the substrate;

the first micro-features and the second micro-features are present together at a second region of the major surface further from the edge of the substrate than the first region; and

the second micro-features are greater in density than the first micro-features in the first region than in the second region.

5. The article of manufacture of claim 1 , wherein the second micro-features decrease in surface roughness with increasing distance from an edge of the substrate.

6. A lighting assembly, comprising:

the article of manufacture of claim 1 ; and

solid-state light emitters to edge light the article of manufacture along an edge of the article of manufacture, wherein

the article of manufacture is a light guide and the micro-features are micro-optical elements;

the first micro-features and the second micro-features are present together at a first region of the major surface near the edge;

the first micro-features and the second micro-features are present together at a second region of the major surface further from the edge than the first region; and

a percentage of the micro-features that are the second micro-features decreases with increasing distance from the edge such that a percentage of the second micro-features from among the first and second micro-features at the first region is greater than a percentage of the second micro-features from among the first and second micro-features at the second region.

7. A lighting assembly, comprising:

the article of manufacture of claim 1 ; and

solid-state light emitters to edge light the article of manufacture along an edge of the article of manufacture, wherein

the article of manufacture is a light guide and the micro-features are micro-optical elements; and

the second micro-features decrease in surface roughness with increasing distance from the edge.

8. A lighting assembly, comprising:

the article of manufacture of claim 1 , wherein the article of manufacture is a light guide and the micro-features are micro-optical elements; and

solid-state light emitters to edge light the light guide along an edge of the light guide, wherein:

the first micro-features and the second micro-features are present together at a first region of the major surface in front of one of the solid-state light emitters;

the first micro-features and the second micro-features are present together at a second region of the major surface at a location approximately mid-way between adjacent solid-state light emitters; and

a percentage of the micro-features that are the second micro-features varies with increasing distance from the edge such that a percentage of the second micro-optical elements from among the first and second micro-features at the first region is greater at the first region than a percentage of the second micro-features from among the first and second micro-features at the second region.

9. A lighting assembly, comprising:

the article of manufacture of claim 1 , wherein the article of manufacture is a light guide and the micro-features are micro-optical elements; and

solid-state light emitters to edge light the light guide along an edge of the light guide, wherein the second micro-features vary in surface roughness with increasing distance from the edge such that the surface roughness of the second micro-optical elements is greater in front of each solid-state light emitter than at locations approximately mid-way between adjacent solid-state light emitters.

10. The article of manufacture of claim 1 , wherein the article of manufacture is a patterning tool for use in making an optical substrate to form at a major surface of the optical substrate first micro-optical elements of well-defined shape defined by the first micro-features and second micro-optical elements of well-defined shape defined by the second micro-features.

11. The article of manufacture of claim 1 , wherein the substrate is a light guide, the first micro-features are first micro-optical elements having a low surface roughness and the second micro-features are second micro-optical elements comprising a surface having a high surface roughness.

12. The article of manufacture of claim 11 , wherein:

the first micro-optical element extracts light from the light guide with a first light ray angle distribution; and

the second micro-optical element extracts light from the light guide with a second light ray angle distribution broader than the first light ray angle distribution.

13. The article of manufacture of claim 1 , wherein the substrate is a light redirecting film, the first micro-features are first micro-optical elements having a low surface roughness and the second micro-features are second micro-optical elements comprising a surface having a high surface roughness.

14. The article of manufacture of claim 1 , wherein:

each of the first micro-features comprises a plurality of distinct surfaces on a scale larger than the surface roughness of the surface of the first micro-feature; and

each of the second micro-features comprises a plurality of distinct surfaces on a scale larger than the surface roughness of the surface of the second micro-feature.

15. The article of manufacture of claim 1 , wherein a percentage of the second micro-features from among the first and second micro-features is substantially uniform over the major surface.

16. The article of manufacture of claim 1 , wherein for each of the plurality of second micro-features, a larger of a length and width of the micro-feature is less than one-half of the smaller of a length and width of the substrate.

17. An article of manufacture, comprising:

a substrate having a major surface;

a plurality of distinct first micro-features of well-defined shape at the major surface of the substrate, each of the first micro-features embodied as a three-dimensional feature recessed into or protruding from the major surface and having a distinct surface on a scale larger than the surface roughness of the surface of the first micro-feature, the surface of the respective first micro-features having a low surface roughness; and

a plurality of distinct second micro-features of well-defined shape at the major surface of the substrate, each of the second micro-features embodied as a three-dimensional feature recessed into or protruding from the major surface and having a distinct surface on a scale larger than the surface roughness of the surface of the second micro-feature, the surface of the respective second micro-features comprising a high surface roughness substantially greater than the low surface roughness,

wherein:

a shape of each of the plurality of first micro-features is nominally the same as a shape of each of the plurality of second micro-features, with the surface of the respective first micro-features having the low surface roughness and the surface of the respective second micro-features having the high surface roughness;

the surface of each of the first micro-features is a first surface and each of the first micro-features additionally comprises a second surface that comes together with the first surface to form a ridge having ends that intersect the major surface; and

the surface of each of the second micro-features is a first surface and each of the second micro-features additionally comprises a second surface that comes together with the first surface to form a ridge having ends that intersect the major surface.

18. The article of manufacture of claim 3 , wherein the substrate is a light guide, the first micro-features are first micro-optical elements having a low surface roughness and the second micro-features are second micro-optical elements comprising a surface having a high surface roughness.

19. The article of manufacture of claim 3 , wherein the substrate is a light redirecting film, the first micro-features are first micro-optical elements having a low surface roughness and the second micro-features are second micro-optical elements comprising a surface having a high surface roughness.

20. The article of manufacture of claim 17 , wherein the substrate is a light guide, the first micro-features are first micro-optical elements having a low surface roughness and the second micro-features are second micro-optical elements comprising a surface having a high surface roughness.

21. The article of manufacture of claim 17 , wherein the substrate is a light redirecting film, the first micro-features are first micro-optical elements having a low surface roughness and the second micro-features are second micro-optical elements comprising a surface having a high surface roughness.