USRE46418EActiveUtility
Optical sky-sun diffuser
Est. expiryJun 24, 2028(~2 yrs left)· nominal 20-yr term from priority
F21S 8/033H01L 2933/0091F21W 2131/103F21Y 2101/02G02B 6/0041F21Y 2101/025F21V 9/16F21V 9/02G02B 6/001H01L 33/50F21W 2121/00F21K 9/00H10H 20/882H10H 20/851F21V 9/30G02B 19/0071G02B 5/0242G02B 19/0047F21V 9/40F21Y 2115/30F21K 9/61F21Y 2115/10G02B 6/0096F21V 3/00F21V 9/08G02B 27/30
86
PatentIndex Score
3
Cited by
33
References
33
Claims
Abstract
An embodiment of a solid optical sky-sun diffuser, which comprises a transparent solid matrix embedding a dispersion of transparent nanoparticles having an average size d in the range 10 nm≦d≦240 nm; wherein: the ratio between the blue and red scattering optical densities γ≡Log [T(450 nm)]/Log [T(630 nm)] of said diffuser falls in the range 5≧γ≧2.5, where T(λ) is the Monochromatic Normalized Collinear Transmittance; in at least one propagation direction, said Monochromatic Normalized Collinear Transmittance is T(450 nm)≧0.4; in at least one propagation direction said Monochromatic Normalized Collinear Transmittance is T(450 nm)≦0.9, said propagation direction being the same or different from that at which said Monochromatic Normalized Collinear Transmittance is T(450 nm)≧0.4.
Claims
exact text as granted — not AI-modifiedThe invention claimed is:
1. A solid optical diffuser which comprises a transparent solid matrix embedding a dispersion of transparent nanoparticles, wherein:
said nanoparticles have an average size d in the range 10 nm≦d≦240 nm;
the ratio between the blue and red scattering optical densities γ≡Log[T(450 nm)]/Log[T(630 nm)] of said solid optical diffuser falls in the range 5≧γ≧2.5, where T(λ) is the monochromatic normalized collinear transmittance of the solid optical diffuser, which is the ratio between the transmittance of the solid optical diffuser, without the contribution of scattered light, and the transmittance of a reference sample identical to the solid optical diffuser except for the fact that it does not contain nanoparticles;
along at least a first propagation direction, the monochromatic normalized collinear transmittance of the solid optical diffuser is T(450 nm)≧0.4; and
along at least a second propagation direction, the monochromatic normalized collinear transmittance of the solid optical diffuser is T(450 nm)≦0.9.
2. The solid optical diffuser according to claim 1 , wherein the relative refraction index
m
≡
n
p
n
h
,
where n p is the refractive index of said nanoparticles and n h is the refractive index of said transparent solid matrix, falls in the range 0.7≦m≦2.1, and the effective particle diameter, D≡dn h , fulfills D[nm]≦132 m+115 if 0.7≦m<1; D[nm]≦240 if 1<m<1.35 and D[nm]≦−135 m+507 if 1.35≦m≦2.1.
3. The solid optical diffuser according to claim 2 , wherein, along at least the first propagation direction, the number of nanoparticles per unit area is
N
≤
N
m
ax
=
3.7
×
10
-
28
D
6
m
2
+
2
m
2
-
1
2
[
meters
-
2
]
,
D being given in meters.
4. The solid optical diffuser according to claim 3 , wherein, along at least the second propagation direction, the number of nanoparticles per unit area is
N
≥
N
m
i
n
=
4.24
×
10
-
29
D
6
m
2
+
2
m
2
-
1
2
[
meters
-
2
]
,
D being given in meters.
5. The solid optical diffuser according to claim 1 , wherein the maximum filling fraction is f≦10 −2 .
6. The solid optical diffuser according to claim 1 , moreover being shaped as a parallelepiped panel where the ratio between the largest dimension, L, and the smallest dimension, W, is L/W≧20.
7. The solid optical diffuser according to claim 1 , wherein the ratio between the blue and red scattering optical densities γ is comprised in the range 3.5≦γ≦5, and wherein:
along said first propagation direction, the monochromatic normalized collinear transmittance of the solid optical diffuser is T(450 nm)≧0.6; and
along said second propagation direction, the monochromatic normalized collinear transmittance of the solid optical diffuser is T(450 nm)≦0.7.
8. The solid optical diffuser according to claim 1 , wherein said second propagation direction is the same as said first propagation direction.
9. The solid optical diffuser according to claim 1 , wherein said second propagation direction is orthogonal to said first propagation direction, and wherein along said second propagation direction the monochromatic normalized collinear transmittance of the solid optical diffuser is T(λ)≦0.5 for λ≦570 nm.
10. The solid optical diffuser according to claim 9 , wherein along said second propagation direction the monochromatic normalized collinear transmittance of the solid optical diffuser is T(λ)≦0.1 for λ≦570 nm.
11. The solid optical diffuser according to claim 9 , wherein the relative refraction index
m
≡
n
p
n
h
,
where n p is the refractive index of said nanoparticles and n h is the refractive index of said transparent solid matrix, falls in the range 0.7≦m≦2.1, and the effective particle diameter, D≡dn h , fulfills D[nm]≦132m+115 if 0.7≦m<1; D[nm]≦240 if 1<m<1.35 and D[nm]≦−135 m+507 if 1.35≦m≦2.1.
12. The solid optical diffuser according to claim 11 , wherein, along at least the first propagation direction, the number of nanoparticles per unit area is
N
≤
N
m
ax
=
3.7
×
10
-
28
D
6
m
2
+
2
m
2
-
1
2
[
meters
-
2
]
,
D being given in meters.
13. The solid optical diffuser according to claim 12 , wherein, along at least the second propagation direction, the number of nanoparticles per unit area is
N
≥
N
m
i
n
=
4.24
×
10
-
29
D
6
m
2
+
2
m
2
-
1
2
[
meters
-
2
]
,
D being given in meters.
14. The solid optical diffuser according to claim 9 , wherein the maximum filling fraction is f≦10 −3 .
15. The solid optical diffuser according to claim 9 , moreover being shaped as a parallelepiped panel where the ratio between the largest dimension, L, and the smallest dimension, W, is L/W≧10.
16. The solid optical diffuser according to claim 15 , configured to be side-lit by a light source so that the light generated by the light source is partially guided inside the parallelepiped panel by total internal reflection and partially scattered out of the parallelepiped panel because of the action of the nanoparticles dispersed in the panel.
17. An illumination system comprising a solid optical diffuser according to claim 9 and a light source, the solid optical diffuser and the light source being configured so that the light emitted by the light source is at least partially guided inside the solid optical diffuser.
18. The solid optical diffuser according to claim 1, further comprising:
a mirror surface having the transparent solid matrix applied thereon.
19. The solid optical diffuser according to claim 18, wherein the solid optical diffuser is shaped as a flat panel, whose length (L), height (H) width (W) fulfill L≧H>>W.
20. The solid optical diffuser according to claim 1, further comprising:
a high-reflectivity coating deposited on one face of the transparent solid matrix.
21. The solid optical diffuser according to claim 20, wherein the solid optical diffuser is shaped as a flat panel, whose length (L), height (H) width (W) fulfill L≧H>>W.
22. The solid optical diffuser according to claim 20, wherein the high-reflectivity coating is deposited on one of the two largest faces of the transparent solid matrix.
23. The solid optical diffuser according to claim 1, wherein the solid optical diffuser is shaped as a flat panel, whose length (L), height (H) width (W) fulfill L≧H>>W.
24. A solid optical diffuser shaped as a flat panel, whose length (L), height (H) width (W) fulfill L≧H>>W, the solid optical diffuser comprising
a transparent solid matrix embedding a dispersion of transparent nanoparticles, and
a reflecting back surface,
wherein:
said nanoparticles have an average size d in the range 10 nm≦d≦240 nm;
the ratio between the blue and red scattering optical densities Log[T(450 nm)]/Log[T(630 nm)] of said solid optical diffuser falls in the range 5≧γ≧2.5, where T(λ) is the monochromatic normalized collinear transmittance of the solid optical diffuser, which is the ratio between the transmittance of the solid optical diffuser, without the contribution of scattered light, and the transmittance of a reference sample identical to the solid optical diffuser except for the fact that it does not contain nanoparticles;
along at least a first propagation direction, the monochromatic normalized collinear transmittance of the solid optical diffuser is T(450 nm)≧0.4; and
along at least a second propagation direction, the monochromatic normalized collinear transmittance of the solid optical diffuser is T(450 nm)≦0.9.
25. The solid optical diffuser according to claim 24, wherein the relative refraction index
m
≡
n
p
n
h
,
where n p is the refractive index of said nanoparticles and n h is the refractive index of said transparent solid matrix, falls in the range 0.7≦m≦2.1, and the effective particle diameter, D≡dn h , fulfills D[nm]≦132 m+115 if 0.7≦m<1; D[nm]≦240 if 1<m<1.35 and D[nm]≦−135 m+507 if 1.35≦m≦2.1.
26. The solid optical diffuser according to claim 25, wherein, along at least the first propagation direction, the number of nanoparticles per unit area is
N
≤
N
m
ax
=
3.7
×
10
-
28
D
6
m
2
+
2
m
2
-
1
2
[
meters
-
2
]
,
D being given in meters.
27. The solid optical diffuser according to claim 26, wherein, along at least the second propagation direction, the number of nanoparticles per unit area is
N
≥
N
m
i
n
=
4.24
×
10
-
29
D
6
m
2
+
2
m
2
-
1
2
[
meters
-
2
]
,
D being given in meters.
28. The solid optical diffuser according to claim 24, wherein the maximum filling fraction is f≦10 −2 .
29. The solid optical diffuser according to claim 24, wherein the solid optical diffuser is shaped as a parallelepiped panel where the ratio between the largest dimension, L, and the smallest dimension, W, is L/W≧20.
30. The solid optical diffuser according to claim 24, wherein the ratio between the blue and red scattering optical densities γ is in the range 3.5≦γ≦5, and wherein:
along said first propagation direction, the monochromatic normalized collinear transmittance of the solid optical diffuser is T(450 nm)≧0.6; and
along said second propagation direction, the monochromatic normalized collinear transmittance of the solid optical diffuser is T(450 nm)≦0.7.
31. The solid optical diffuser according to claim 24, wherein said second propagation direction is the same as said first propagation direction.
32. The solid optical diffuser according to claim 24, wherein said second propagation direction is orthogonal to said first propagation direction, and wherein along said second propagation direction the monochromatic normalized collinear transmittance of the solid optical diffuser is T(λ)≦0.5 for λ≦570 nm.
33. The solid optical diffuser according to claim 32, wherein along said second propagation direction the monochromatic normalized collinear transmittance of the solid optical diffuser is T(λ)≦0.1 for λ≦570 nm, and
wherein the relative refraction index
m
=
n
p
n
h
,
where n p is the refractive index of said nanoparticles and n h is the refractive index of said transparent solid matrix, falls in the range 0.7≦m≦2.1, and the effective particle diameter, D≡dn h , fulfills D[nm]≦132 m+115 if 0.7≦m<1; D[nm]≦240 if 1<m<1.35 and D[nm]≦−135 m+507 if 1.35≦m≦2.1, and
wherein, along at least the first propagation direction, the number of nanoparticles per unit area is
N
≤
N
ma
x
=
3.7
×
10
-
28
D
6
m
2
+
2
m
2
-
1
2
[
meters
-
2
]
,
D being given in meters, and
wherein, along at least the second propagation direction, the number of nanoparticles per unit area is
N
≥
N
m
i
n
=
4.24
×
10
-
29
D
6
m
2
+
2
m
2
-
1
2
[
meters
-
2
]
,
D being given in meters.Cited by (0)
No later patents cite this yet.
References (0)
No backward citations on record.