Sheet and light emitting device
A sheet and a light emitting device are provided which also emit light having an incident angle larger than or equal to a critical angle to significantly increase light extraction efficiency, prevent ambient light reflection, and suppress the occurrence of a distribution of light intensity varying depending on the direction and an imbalance in color. The light emitting device has a surface structure ( 13 ) in a surface adjacent to a light emitting element of a transparent substrate ( 5 ). The surface of the transparent substrate ( 5 ) is virtually divided into minute regions without a gap, the diameter of a largest circle inscribed in the minute region being 0.2 μm or more and 1.5 μm or less. Each minute region has a convex or concave shape in the surface of the transparent substrate 5 . The proportions of the convex shapes and the concave shapes are P and 1−P, respectively, where P is within the range of 0.4 to 0.98.
1. A transparent sheet having a first surface and a second surface, wherein
the first surface is adjacent to a light emitting element in use,
the second surface includes a plurality of minute regions δ comprising a plurality of minute regions δ 1 and a plurality of minute regions δ 2 ,
the plurality of minute regions δ 1 being randomly arranged and accounting for 40% or more and 98% or less of the plurality of minute regions δ, and the plurality of minute regions δ 2 being the other minute regions δ,
among the plurality of minute regions δ, a diameter of a largest circle inscribed in the minute region δ being 0.2 μm or more and 8.0 μm or less, and one minute region δ being adjacent to and surrounded by a plurality of other minute regions δ,
each minute region δ 1 projects to a position above the minute region δ 2 ,
each minute region δ 2 dents to a position below the minute region δ 1 , each minute region δ 1 having a height d above a bottom of each minute region δ 2 ,
and
d is 0.2 μm or more and 1.4 μm or less.
2. A transparent sheet having a first surface and a second surface, wherein
the first surface is adjacent to and in contact with a light emitting element in use,
the second surface includes a plurality of minute regions δ, a diameter of a largest circle inscribed in the minute region δ being 0.2 μm or more and 8.0 μm or less, and one minute region δ being adjacent to and surrounded by a plurality of other minute regions δ,
each of the plurality of minute regions δ is located at a random height in a direction perpendicular to the second surface, the plurality of minute regions δ including a minute region δ located at a highest position and a minute region δ located at a lowest position in the direction perpendicular to the second surface, the minute region δ located at the highest position having a height d above a bottom of the minute region δ located at the lowest position, the bottom of which is at the second surface, and
d is 0.2 μm or more and 1.4 μm or less.
3. A transparent sheet having a first surface and a second surface, wherein
the first surface is adjacent to and in contact with a light emitting element in use,
the second surface includes a plurality of minute regions δ, a diameter of a largest circle inscribed in the minute region δ being 0.4 μm or more and 4.0 μm or less, and one minute region δ being adjacent to and surrounded by a plurality of other minute regions δ,
the plurality of minute regions δ include a plurality of minute regions δ 1 and a plurality of minute regions δ 2 , and
the minute region δ 1 and the minute region δ 2 cause light transmitted through the minute region δ 1 and light transmitted through the minute region δ 2 after entering the first surface in a direction perpendicular to the one surface, to generate a phase difference of 180 degrees.
4. The sheet of any one of claims 1 to 3 , wherein
the minute regions δ have congruent polygonal shapes.
5. A light emitting device comprising a light emitting element, and a transparent protective layer provided on a light emission surface of the light emitting element, wherein
a second surface opposite to a first surface adjacent to the light emission surface of the protective layer includes a plurality of minute regions δ comprising a plurality of minute regions δ 1 and a plurality of minute regions δ 2 ,
the plurality of minute regions δ 1 being randomly arranged and accounting for 40% or more and 98% or less of the plurality of minute regions δ, and the plurality of minute regions δ 2 being the other minute regions δ,
among the plurality of minute regions δ, a diameter of a largest circle inscribed in the minute region δ being 0.2 μm or more and 8.0 μm or less, and one minute region δ being adjacent to and surrounded by a plurality of other minute regions δ,
each minute region δ 1 projects to a position above the minute region δ 2 ,
each minute region δ 2 dents to a position below the minute region δ 1 , each minute region δ 1 having a height d above a bottom of each minute region δ 2 ,
the light emitting element emits light having a center wavelength λ of an emission spectrum, and
λ/6(n 1 −n 0 )<d<λ/(n 1 −n 0 ), where n 1 represents a refractive index of the protective layer, n 0 represents a refractive index of a medium contacting the second surface of the protective layer, and n 0 <n 1 .
6. A light emitting device comprising a light emitting element, and a transparent protective layer provided on a light emission surface of the light emitting element, wherein
a second surface opposite to a first surface adjacent to the light emission surface of the protective layer includes a plurality of minute regions δ, a diameter of a largest circle inscribed in the minute region δ being 0.2 μm or more and 8.0 μm or less, and one minute region δ being adjacent to and surrounded by a plurality of other minute regions δ,
each of the plurality of minute regions δ is located at a random height in a direction perpendicular to the second surface, the plurality of minute regions δ including a minute region δ located at a highest position and a minute region δ located at a lowest position in the direction perpendicular to the second surface, the minute region δ located at the highest position having a height d above a bottom of the minute region δ located at the lowest position, the bottom of which is at the second surface,
the light emitting element emits light having a center wavelength λ of an emission spectrum, and
λ/6(n 1 −n 0 )<d<λ/(n 1 −n 0 ), where n 1 represents a refractive index of the protective layer, n 0 represents a refractive index of a medium contacting the second surface of the protective layer, and n 0 <n 1 .
7. A light emitting device comprising a light emitting element, and a transparent protective layer provided on a light emission surface of the light emitting element, wherein
a second surface opposite to a first surface adjacent to and in contact with the light emission surface of the protective layer includes a plurality of minute regions δ, a diameter of a largest circle inscribed in the minute region δ being 0.4 μm or more and 4.0 μm or less, and one minute region δ being adjacent to and surrounded by a plurality of other minute regions δ,
the plurality of minute regions δ include a plurality of minute regions δ 1 and a plurality of minute regions δ 2 , and
the minute region δ 1 and the minute region δ 2 cause light transmitted through the minute region δ 1 and light transmitted through the minute region δ 2 after entering the first surface adjacent to the light emission surface of the protective layer in a direction perpendicular thereto, to generate a phase difference of 180 degrees.
8. The light emitting device of claim 5 or 6 , wherein
the medium is air.
9. The light emitting device of claim 5 or 6 , wherein
the medium is an aerogel.
10. The light emitting device of claim 5 wherein
n 2 −n 1 <0.1, where n 2 represents a refractive index of a portion of the light emitting element in which light is produced.
11. The light emitting device of claim 6 , wherein
n 2 −n 1 <0.1, where n 2 represents a refractive index of a portion of the light emitting element in which light is produced.
12. The light emitting device of claim 8 , wherein
n 2 −n 1 <0.1, where n 2 represents a refractive index of a portion of the light emitting element in which light is produced.
13. The light emitting device of claim 9 , wherein
n 2 −n 1 <0.1, where n 2 represents a refractive index of a portion of the light emitting element in which light is produced.
14. The light emitting device of claim 1 , wherein
the diameter of a largest circle inscribed in the minute region δ being 0.2 μm or more and 1.5 μm or less.
15. The light emitting device of claim 2 , wherein
the diameter of a largest circle inscribed in the minute region δ being 0.2 μm or more and 1.5 μm or less.
16. The light emitting device of claim 3 , wherein
the diameter of a largest circle inscribed in the minute region δ being 0.4 μm or more and 1.0 μm or less.
17. The light emitting device of claim 5 , wherein
the diameter of a largest circle inscribed in the minute region δ being 0.2 μm or more and 1.5 μm or less.
18. The light emitting device of claim 6 , wherein
the diameter of a largest circle inscribed in the minute region δ being 0.2 μm or more and 1.5 μm or less.
19. The light emitting device of claim 7 , wherein
the diameter of a largest circle inscribed in the minute region δ being 0.4 μm or more and 1.0 μm or less.
20. The transparent sheet of claim 1 , wherein at least one of the minute regions δ has a cross-sectional shape perpendicular to the second surface that is a trapezoid.
21. The transparent sheet of claim 2 , wherein at least one of the minute regions δ has a cross-sectional shape perpendicular to the second surface that is a trapezoid.
22. The transparent sheet of claim 3 , wherein at least one of the minute regions δ has a cross-sectional shape perpendicular to the second surface that is a trapezoid.
23. The transparent sheet of claim 1 , wherein at least one of the minute regions δ has a curved slanting surface.
24. The transparent sheet of claim 2 , wherein at least one of the minute regions δ has a curved slanting surface.
25. The transparent sheet of claim 3 , wherein at least one of the minute regions δ has a curved slanting surface.
26. The light emitting device of claim 5 , wherein at least one of the minute regions δ has a cross-sectional shape perpendicular to the second surface that is a trapezoid.
27. The light emitting device of claim 6 , wherein at least one of the minute regions δ has a cross-sectional shape perpendicular to the second surface that is a trapezoid.
28. The light emitting device of claim 7 , wherein at least one of the minute regions δ has a cross-sectional shape perpendicular to the second surface that is a trapezoid.
29. The transparent sheet of claim 5 , wherein at least one of the minute regions δ has a curved slanting surface.
30. The transparent sheet of claim 6 , wherein at least one of the minute regions δ has a curved slanting surface.
31. The transparent sheet of claim 7 , wherein at least one of the minute regions δ has a curved slanting surface.
32. The transparent sheet of claim 2 , wherein the light emitting element is an organic electroluminescence element (EL).
33. The transparent sheet of claim 3 , wherein the light emitting element is an organic electroluminescence element (EL).
34. The light emitting device of claim 6 , wherein the light emitting element is an organic EL element.
35. The light emitting device of claim 7 , wherein the light emitting element is an organic EL element.
36. The light emitting device of claim 5 - 7 , the medium contacting the second surface of the protective layer is a transparent material.
37. A light emitting device comprising a first electrode, a light emitting layer, a second electrode, an adhesion layer, and a transparent material, in this order, wherein
the adhesion layer and the transparent material are adjacent to each other,
a second surface of the adhesion layer opposite to a first surface of the adhesion layer adjacent to the transparent material includes a plurality of minute regions δ comprising a plurality of minute regions δ 1 and a plurality of minute regions δ 2 ,
the plurality of minute regions δ 1 being randomly arranged and accounting for 40% or more and 98% or less of the plurality of minute regions δ, and the plurality of minute regions δ 2 being the other minute regions δ,
among the plurality of minute regions δ, a diameter of a largest circle inscribed in the minute region δ being 0.2 μm or more and 8.0 μm or less, and one minute region δ being adjacent to and surrounded by a plurality of other minute regions δ,
each minute region δ 1 projects to a position above the minute region δ 2 ,
each minute region δ 2 dents to a position below the minute region δ 1 , each minute region δ 1 having a height d above a bottom of each minute region δ 2 ,
the light emitting element emits light having a center wavelength λ of an emission spectrum, and
λ/6(n 1 −n 0 )<d<λ/(n 1 −n 0 ), where n 1 represents a refractive index of the adhesion layer, n 0 represents a refractive index of the transparent material, and n 0 <n 1 .
38. The transparent sheet of claim 3 , wherein the plurality of minute regions δ have a same shape.