Multiple-cell LED arrangement, related cell and manufacturing process

1. A multiple-cell LED arrangement comprising:

a plurality of cells ( 0 , 1 , 2 , 3 ) each including at least one respective LED having a binning class as a function of its emission wavelength (Li, L 2 ) and brightness (Bi, B 2 ) characteristics;

a plurality of impedance elements (R 0 , R 1 , R 2 , R 3 ) respectively coupled with said cells ( 0 , 1 , 2 , 3 ), each said impedance element (R 0 , R 1 , R 2 , R 3 ) having an impedance value indicative of the binning class of said at least one LED included in the respective cell ( 0 , 1 , 2 , 3 ); and

a controller ( 5 ) configured for sensing ( 6 , 80 , 81 , 82 , 83 ) the impedance values of said impedance elements (R 0 , R 1 , R 2 , R 3 ) and adaptively drive each said cell ( 0 , 1 , 2 , 3 ) as a function of its binning class as indicated by the impedance element (R 0 , R 1 , R 2 , R 3 ) coupled to the cell.

2. The arrangement of claim 1 , wherein said impedance elements are resistors (R 0 , R 1 , R 2 , R 3 ) and said impedance value is a resistance value.

3. The arrangement of claim 1 , wherein at least one of said impedance elements (R 0 , R 1 , R 2 , R 3 ) has a zero impedance value.

4. The arrangement of claim 1 , further comprising, coupled with each of said cells ( 0 , 1 , 2 , 3 ), a switch (S 0 , S 1 , S 2 , S 3 ) to selectively activate the impedance element (R 0 , R 1 , R 2 , R 3 ) coupled to the respective cell ( 0 , 1 , 2 , 3 ) to sense the impedance value thereof.

5. The arrangement of claim 1 , further comprising:

a power source ( 4 ) to produce a current flow for energizing said cells ( 0 , 1 , 2 , 3 ); and

a switch (S 0 , S 1 , S 2 , S 3 ) coupled with each said cell ( 0 , 1 , 2 , 3 ) to selectively deviate said current flow towards and away from said at least one LED in the respective cell ( 0 , 1 , 2 , 3 ).

6. The arrangement of claim 4 , wherein said impedance element (R 0 , R 1 , R 2 , R 3 ) is series connected with said switch (S 0 , S 1 , S 2 , S 3 ).

7. The arrangement of claim 5 , further comprising a controller ( 5 ) for selectively opening and closing said switch (S 0 , S 1 , S 2 , S 3 ) coupled with each of said cells ( 0 , 1 , 2 , 3 ) to selectively energize and de-energize each of said cells ( 0 , 1 , 2 , 3 ).

8. The arrangement of claim 7 , wherein said controller ( 5 ) is coupled with a sensor ( 6 ) for sensing the voltage across at least one of:

said respective impedance element (R 0 , R 1 , R 2 , R 3 ) coupled with each said cells ( 0 , 1 , 2 , 3 ), and

said at least one LED included in said cells ( 0 , 1 , 2 , 3 ).

9. A LED cell ( 0 , 1 , 2 , 3 ) for a multiple-cell LED arrangement, comprising:

at least one LED having a binning class as a function of its emission wavelength (Li, L 2 ) and brightness (Bi, B 2 ) characteristics,

an impedance element (R 0 , R 1 , R 2 , R 3 ) coupled with said cell ( 0 , 1 , 2 , 3 ), said impedance element (R 0 , R 1 , R 2 , R 3 ) having an impedance value indicative of the binning class of said at least one LED.

10. The cell of claim 9 , wherein said impedance element is a resistor (R 0 , R 1 , R 2 , R 3 ), and said impedance value is a resistance value.

11. The cell of claim 9 , further comprising a switch (S 0 , S 1 , S 2 , S 3 ) to selectively activate said impedance element (R 0 , R 1 , R 2 , R 3 ) coupled to the cell ( 0 , 1 , 2 , 3 ) to sense the impedance value thereof.

12. The cell of claim 9 , further comprising a switch (S 0 , S 1 , S 2 , S 3 ) coupled with said cell ( 0 , 1 , 2 , 3 ) to selectively deviate a current flow towards and away from said at least one LED in the cell ( 0 , 1 , 2 , 3 ).

13. The cell of claim 11 , wherein said impedance element (R 0 , R 1 , R 2 , R 3 ) is series connected with said switch (S 0 , S 1 , S 2 , S 3 ).

14. A process for manufacturing LED cells ( 0 , 1 , 2 , 3 ) for multiple-cell LED arrangements, wherein said cells include at least one respective LED having a binning class as a function of its emission wavelength (Li, L 2 ) and brightness (Bi, B 2 ) characteristics, the process including the step of respectively coupling with said cells ( 0 , 1 , 2 , 3 ) impedance elements (R 0 , R 1 , R 2 , R 3 ), each said impedance element (R 0 , R 1 , R 2 , R 3 ) having an impedance value indicative of the binning class of said at least one LED included in the respective, cell ( 0 , 1 , 2 , 3 ).

15. The process of claim 14 , wherein said impedance element is a resistor (R 0 , R 1 , R 2 , R 3 ), and said impedance value is a resistance value.

16. The process of claim 14 , further comprising the step of coupling with said cells ( 0 , 1 , 2 , 3 ) a switch (S 0 , S 1 , S 2 , S 3 ) to selectively activate said impedance element (R 0 , R 1 , R 2 , R 3 ) to sense the impedance value thereof.

17. The process of claim 14 , further comprising the step of coupling with said cells ( 0 , 1 , 2 , 3 ) a switch (S 0 , S 1 , S 2 , S 3 ) to selectively deviate a current flow towards and away from said at least one LED in the respective cell ( 0 , 1 , 2 , 3 ).

18. The process of claim 16 , further comprising the step of series connecting said impedance element (R 0 , R 1 , R 2 , R 3 ) with said switch (S 0 , S 1 , S 2 , S 3 ).

19. The process of claim 14 , further comprises the steps of:

coupling with said cell ( 0 , 1 , 2 , 3 ) an impedance-generating element, and

trimming said impedance-generating element to have an impedance value indicative of the binning class of said at least one LED.

20. The process of claim 19 , wherein said impedance-generating element is a strip-like impedance element, and said step of trimming includes cutting to length said strip-like impedance element.