Linear lenses for LEDs
Various embodiments described herein comprise array of light emitting diodes and a cylindrical lens having front and rear curved surfaces. The cylindrical lens is disposed to receive light from the light emitting diodes and to redistribute the light. The cylindrical lens is located no more than about 8 inches distance from the front an illumination target, which may for example, comprise products on shelves in a refrigerator. The front and rear surfaces of the cylindrical lens are shaped to provide substantially uniform illumination across the target.
1. A lighting system comprising:
an array of light emitting diodes; and
a cylindrical lens having a central portion and a pair of surrounding outer portions, said cylindrical lens disposed to receive light from said light emitting diodes to redistribute said light,
wherein (i) said central portion is shaped to uniformly illuminate a first planar region disposed a first distance from said array and (ii) said outer portions of said cylindrical lens are shaped to uniformly illuminate outer portions of a second planar region at a second distance from the array.
2. The lighting system of claim 1 , wherein said second distance is less than said first distance.
3. A refrigerator door assembly comprising a door frame, said lighting system of claim 1 secured to said refrigerator door assembly.
4. The refrigerator door assembly of claim 3 , further comprising at least one refrigerator door.
5. A refrigerator comprising:
a refrigerator door frame;
at least one refrigerator door;
a refrigerator compartment; and
at least one shelf positioned in said refrigerator compartment;
said lighting system of claim 1 disposed such that a front edge of said at least one shelf intersects said first or second planar regions.
6. A refrigerator comprising:
a refrigerator door frame;
at least one refrigerator door;
a refrigerator compartment;
a plurality of shelves positioned in said refrigerator compartment such that front edges of said plurality of shelves form a product display plane transverse to said plurality of shelves;
an array of light emitting diodes; and
a cylindrical lens having front and rear curved surfaces, said cylindrical lens disposed to receive light from said light emitting diodes and to redistribute said light, said cylindrical lens being located no more than about 8 inches distance from the front edges of said plurality of shelves,
wherein said front and rear surfaces of said cylindrical lens are shaped to provide substantially uniform illumination across a portion of said product display plane having a width substantially equal to the width of said front edge of one of said shelves.
7. The refrigerator of claim 6 , wherein said substantially uniform illumination varies by no more than about 30% per inch.
8. The refrigerator of claim 6 , wherein said front and rear curved surfaces are shaped to provide substantially uniform illumination across outer regions of a second plane disposed no more than 2 inches from said cylindrical lens.
9. A refrigerator comprising:
a refrigerator door frame;
at least one refrigerator door;
a refrigerator compartment;
a plurality of shelves positioned in said refrigerator compartment such that front edges of said plurality of shelves form a product display plane transverse to said plurality of shelves;
an array of light emitting diodes; and
a cylindrical lens having front and rear curved surfaces, said cylindrical lens disposed to receive light from said light emitting diodes and to redistribute said light, said cylindrical lens located no more than 2 inches distance from the front edges of said plurality of shelves,
wherein said front and rear surfaces are shaped to provide substantially uniform illumination across a pair of spaced apart regions in said product display plane.
10. The refrigerator of claim 9 , wherein said substantially uniform illumination varies by no more than about 30% per inch across the spaced apart regions of said product display plane.
11. The refrigerator of claim 9 , wherein said front and rear curved surfaces are shaped to provide illumination that varies no more than about 30% per inch across a central region between said pair of spaced apart regions, said central region being between about 6 inches and 12 inches wide.
12. A lighting system comprising:
an array of light emitting diodes; and
a cylindrical lens having a central portion and a pair of surrounding outer portions, said central portion shaped to refract light from the light emitting diodes into an inner distribution of angles and said pair of surrounding outer portions shaped to refract light from the light emitting diodes into an outer distribution of angles disposed about said inner distribution of angles,
such that (i) light in said inner distribution of angles illuminates a central region of a first plane more uniformly than said light in said outer distribution illuminates outer regions of said first plane and (ii) light in said outer distribution illuminates outer regions of a second plane more uniformly than said light in said inner distribution illuminates an inner region of said second plane.
13. The lighting system of claim 12 , wherein the illuminated area of the outer regions of the second plane is at least one-half the illuminated area of the central region of the first plane.
14. A refrigerator door assembly comprising a door frame, said lighting system of claim 12 secured to said refrigerator door assembly.
15. The refrigerator door assembly of claim 14 , further comprising at least one door.
16. A refrigerator comprising:
a refrigerator door frame;
at least one refrigerator door;
a refrigerator compartment; and
at least one shelf positioned in said refrigerator compartment;
said lighting system of claim 12 disposed such that a front edge of said at least one shelf intersects said first or second planes.
17. A lighting system comprising:
an array of light emitting diodes; and
a cylindrical lens having a central portion and a pair of surrounding outer portions,
wherein (i) said central portion is shaped to match the cumulative lateral flux of the array of light emitting diodes with the cumulative lateral flux of a uniformly illuminated central region of a first plane and (ii) said outer portions of said cylindrical lens are shaped to match the cumulative lateral flux of the array of light emitting diodes with the cumulative lateral flux of a uniformly illuminated outer region of a second plane.
18. A refrigerator door assembly comprising a door frame, said lighting system of claim 17 secured to said refrigerator door assembly.
19. A refrigerator door assembly of claim 18 , further comprising at least one door.
20. A refrigerator comprising:
a refrigerator door frame;
at least one refrigerator door;
a refrigerator compartment; and
at least one shelf positioned in said refrigerator compartment;
said lighting system of claim 17 disposed such that a front edge of said at least one shelf intersects said first or second planes.
21. A lighting system comprising:
an array of light emitting diodes; and
a cylindrical lens disposed to receive light from said light emitting diodes to redistribute said light, said cylindrical lens having first and second curved surfaces, said first surface having negative optical power, said second surface having a central portion and a pair of surrounding outer portions, said central portion having negative optical power to increase uniformity in illuminating a first planar region and said outer portions having positive optical power so as to increase uniformity in illuminating a second planar region.
22. The lighting system of claim 21 , wherein said first planar region is located at a first distance from said cylindrical lens and said second planar region is located at a second distance from said cylindrical lens and wherein said second distance is less than said first distance.
23. The lighting system of claim 22 , wherein said second distance is about 2 inches.
24. A refrigerator door assembly comprising a door frame, said lighting system of claim 21 secured to said refrigerator door assembly.
25. The refrigerator door assembly of claim 24 , further comprising at least one door.
26. A refrigerator comprising:
a refrigerator door frame;
at least one refrigerator door;
a refrigerator compartment; and
at least one shelf positioned in said refrigerator compartment;
said lighting system of claim 21 disposed such that a front edge of said at least one shelf intersects said first or second planar regions.
27. A refrigerator comprising:
a refrigerator door frame;
at least one refrigerator door;
a refrigerator compartment;
a plurality of shelves positioned in said refrigerator compartment such that front edges of said plurality of shelves form a product display plane transverse to said plurality of shelves;
an array of light emitting diodes; and
a cylindrical lens having front and rear curved surfaces, said cylindrical lens disposed to receive light from said light emitting diodes and to redistribute said light,
wherein said front and rear surfaces of said cylindrical lens are shaped to match the cumulative lateral flux of the array of light emitting diodes with the cumulative lateral flux of a uniformly illuminated portion of said product display plane.
28. The refrigerator of claim 27 , wherein said cylindrical lens comprises a central portion and an outer portion, and the front surface of the central portion is convex.
29. A refrigerator comprising:
a refrigerator door frame;
at least one refrigerator door;
a refrigerator compartment;
a plurality of shelves positioned in said refrigerator compartment such that front edges of said plurality of shelves form a product display plane transverse to said plurality of shelves;
an array of light emitting diodes; and
a cylindrical lens disposed to receive light from said light emitting diodes to redistribute said light, said cylindrical lens having a central portion and an outer portion, said central portion providing more light divergence than said outer portion so as to increase uniformity in illuminating a planar region.
30. The refrigerator of claim 29 , wherein said central portion has negative power and said outer portion has negative power.
31. The refrigerator of claim 29 , wherein said central portion has positive power and said outer portion has positive power.
32. A lighting system comprising:
an array of light emitting diodes; and
a cylindrical lens having front and rear surfaces, said cylindrical lens disposed to receive light from said light emitting diodes and to redistribute said light, the rear surface comprising side portions; and
a diffuser positioned between said array of light emitting diodes and said cylindrical lens configured to scatter light incident on the side portions of the rear surface,
wherein said front and rear surfaces of said cylindrical lens are shaped to match the cumulative lateral flux of the array of light emitting diodes with the cumulative lateral flux of a uniformly illuminated portion of a planar region.
33. A lighting system comprising:
an array of light emitting diodes;
a cylindrical lens having front and rear surfaces, said cylindrical lens disposed to receive light from said light emitting diodes and to redistribute said light; and
a mask positioned between said array of light emitting diodes and said cylindrical lens, said mask configured to block transmission of light incident thereon,
wherein said front and rear surfaces of said cylindrical lens are shaped to match the cumulative lateral flux of the array of light emitting diodes with the cumulative lateral flux of a uniformly illuminated portion of a planar region.