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An array structure for light emitting diodes (LEDs) uses a patterned metal layer buried beneath LED chips to electrically interconnect non-adjacent chips in series, such that each chip in the LED array can be adjacently surrounded by LED chips of different colors. Thus, when the emission from the LE

An array structure for light emitting diodes (LEDs) uses a patterned metal layer buried beneath LED chips to electrically interconnect non-adjacent chips in series, such that each chip in the LED array can be adjacently surrounded by LED chips of different colors. Thus, when the emission from the LED array is projected to a spot in the far field, its color uniformity over the spot is enhanced. Methods are also described for fabricating the multi-layer circuit board for such an array. Top and bottom patterned metal layers are formed, separated by a patterned insulating layer, so that electrical connections may be made between the metal layers. This provides “vias” between the metal layers for creating “cross-under” electrical connections under the second insulation layer, such that spatially-separated LED chips can be interconnected into strings, while maintaining electrical isolation between LED chips of different colors.

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1. A method, comprising: forming a circuit board, including forming a first conductive layer over an insulating surface of a substrate, the first conductive layer having a plurality of separated sections in a linear arrangement;forming an intermediate insulating layer over the first conductive layer

1. A method, comprising: forming a circuit board, including forming a first conductive layer over an insulating surface of a substrate, the first conductive layer having a plurality of separated sections in a linear arrangement;forming an intermediate insulating layer over the first conductive layer such that the sections of the first conductive layer have a portion at either end along the linear arrangement that is left uncovered by the intermediate insulating layer; andforming a second conductive layer over the first insulating layer, the second conductive layer having a plurality of separated sections each formed over a section of the first conductive layer and separated therefrom by the intermediate insulating layer,wherein, when a pair of sections of the second conductive layer adjacent in the linear arrangement are formed over different sections of the first conductive layer, the first of the pair is formed to connect to the uncovered portion of the first conductive layer under the second of the pair, where the first of the pair is the one furthest in a first direction along linear arrangement. 2. The method of claim 1, wherein the substrate is formed of an electrically insulating material. 3. The method of claim 1, wherein the substrate is conductive and forming the circuit board further comprises: prior to forming the first conductive layer, forming a lower insulating layer over the substrate, the first conductive layer being formed over the lower insulating layer. 4. The method of claim 1, wherein the sections of the first conductive layer are formed to have an arm extending over the substrate at either end along the linear arrangement, the arms being the portions left uncovered by the intermediate insulating layer. 5. The method of claim 1, wherein each of the sections of the second conductive layer are formed over a different section of the first conductive layer. 6. The method of claim 1, wherein the linear arrangement is one of a plurality of such linear arrangements forming a two-dimensional array. 7. The method of claim 1, further comprising: mounting one of each of a plurality of light emitting diodes (LEDs) over or adjacent to a corresponding section of the second conductive layer with a first terminal thereof connected to the corresponding section of the second conductive layer. 8. The method of 7, wherein the plurality of LEDs are mounted on the corresponding section of the second conductive layer and have a vertical type LED structure. 9. The method of 7, wherein the plurality of LEDs are mounted adjacent to the corresponding section of the second conductive layer and have a horizontal type LED structure. 10. The method of 7, further comprising: when a first LED and a second LED are each mounted over or adjacent to one of the corresponding pair of sections of the second conductive layer adjacent in the linear arrangement formed over different sections of the first conductive layer, a second terminal of the LED mounted over or adjacent to the second of the pair is connected to the uncovered portion of the first conductive layer under the first of the pair. 11. The method of claim 10, wherein the plurality of LEDs includes a first set of one or more LEDs of a first type and a second set of one or more LEDs of a second type, and wherein the first and second sets of LEDs are interspersed along the linear arrangement such that the LEDs of each set are connected in series through the first and second conductive layers. 12. The method of claim 11, wherein the first set of LEDs emits a different of color light that the second set of LEDs. 13. The method of claim 11, wherein the LEDs of the first and second sets alternate in the linear arrangement. 14. A method, comprising forming a circuit board, including: forming one or more first patterned conductive layers over an insulating surface of a substrate;forming an upper patterned conductive layer having a plurality of separated portions in a linear arrangement over the substrate, each formed at least partially over a part of one or more of the first patterned conductive layers; andforming one or more intermediate insulating layers between the first and upper patterned conductive layers, whereby the first conductive layers are isolated from one another and from the upper conductive layer,wherein the patterned layers are formed to provide a plurality of independent current paths whereby a corresponding plurality of distinct sets of one or more devices are connectable in series for each set, with the sets of devices interspersed along the linear arrangement, when a first terminal of each device is connected to a corresponding one of the separated portions of the upper patterned conductive layer and a second terminal of each device is connected to one of the patterned conductive layers,such that the devices of each set are connected in series through the one or more first patterned conductive layers when passing under or adjacent to devices of the other sets that are connected to the corresponding one of the separated portions of the upper patterned conductive layer in the linear arrangement. 15. The method of claim 14, wherein the substrate is formed of an electrically insulating material. 16. The method of claim 14, wherein the substrate is conductive and the method and forming the circuit board further comprises: prior to forming the first conductive layer, forming a lower insulating layer over the substrate, the first conductive layer being formed over the lower insulating layer. 17. The method of claim 14, wherein the number of distinct sets of devices is greater than two, and wherein at least one of the first patterned conductive layers is formed of a plurality of horizontally separated, non-connected sections. 18. The method of claim 14, wherein the number of first patterned conductive layers is one, the number of distinct sets of devices two, and the devices are connected to the first patterned conductive layer such that the devices of each set are connected in series through the first patterned conductive layer under the devices of the other set. 19. The method of claim 14, wherein the devices of the two sets alternate in the linear arrangement. 20. The method of claim 14, wherein the linear arrangement is one of a plurality of such linear arrangements forming a two-dimensional array. 21. The method of claim 14, wherein the devices are light emitting diodes (LEDs), the method further comprising: mounting the LEDs over or adjacent to the corresponding section of the second conductive layer with a first terminal thereof connected to the corresponding section of the second conductive layer. 22. The method of 21, wherein the plurality of LEDs are mounted on the corresponding section of the second conductive layer and have a vertical type LED structure. 23. The method of 21, wherein the plurality of LEDs are mounted adjacent to the corresponding section of the second conductive layer and have a horizontal type LED structure. 24. The method of 21, further comprising: when a first LED and a second LED are each mounted over or adjacent to one of the corresponding pair of sections of the second conductive layer adjacent in the linear arrangement formed over different sections of the first conductive layer, a second terminal of the LED mounted over or adjacent to the second of the pair is connected to the first conductive layer under the first of the pair. 25. The method of claim 24, wherein the plurality of LEDs includes a first set of one or more LEDs of a first type and a second set of one or more LEDs of a second type, and wherein the first and second sets of LEDs are interspersed along the linear arrangement such that the LEDs of each set are connected in series through the first and second conductive layers. 26. The method of claim 25, wherein the first set of LEDs emits a different of color light that the second set of LEDs. 27. The method of claim 25, wherein the LEDs of the first and second sets alternate in the linear arrangement. 28. An array of light emitting diodes (LEDs), comprising: a plurality of LEDs, each having first and second terminals and being mounted over a substrate having an insulating surface, wherein the plurality of LEDs includes a first set of one or more LEDs and a second set of one or more LEDs, and where the first and second sets of LEDs are distinct and are interspersed in a linear arrangement along the substrate;a first patterned conductive layer formed over the substrate;a second patterned conductive layer having a plurality of separated portions formed at least partially over the first patterned conductive layer, wherein each of the plurality of LEDs is mounted over or adjacent to a corresponding portion of the second patterned conductive layer and has a first terminal connected thereto; andan intermediate insulating layer formed between the first and second patterned conductive layers,wherein, when a pair of adjacent LEDs in the linear arrangement are from different ones of the first and second sets, a second terminal of a first of the pair is connected to the first patterned conductive layer under the second of the pair, and the first patterned conductive layer under the first of the pair is connected to the second conductive layer under the second of the pair, where the first of the pair is the one furthest in a first direction along the linear arrangement. 29. The array of LEDs of claim 28, wherein the first set of LEDs emits a different of color light that the second set of LEDs. 30. The array of LEDs of claim 28, wherein the LEDs of the first and second sets alternate in the linear arrangement. 31. The array of LEDs of claim 28, wherein the array is a two-dimensional array formed of a plurality of linear arrangements of LEDs, one of which is the linear arrangement formed by the plurality of LEDs. 32. The array of LEDs of claim 28, wherein the substrate is formed of an electrically insulating material. 33. The array of LEDs of claim 28, wherein the substrate is conductive and the array further includes a lower insulating layer formed over the substrate, over which the first patterned conductive layer is formed. 34. The array of LEDs of claim 28, wherein the plurality of LEDs are mounted on the corresponding portion of the second patterned conductive layer and have a vertical type LED structure. 35. The array of LEDs of claim 28, wherein the plurality of LEDs are mounted adjacent to the corresponding portion of the second patterned conductive layer and have a horizontal type LED structure. 36. The array of LEDs of claim 28, wherein each of the plurality of LEDs is die-bonded to the corresponding portion of the second patterned conductive layer. 37. An array of light emitting diodes (LEDs), comprising: a circuit board, including: a substrate having an insulating surface;one or more first patterned conductive layers formed over the insulating surface of the substrate;an upper patterned conductive layer having a plurality of separated portions arranged in a linear arrangement over the substrate, each of the of separated portions being formed at least partially over a part of one or more of the first patterned conductive layers; andone or more intermediate insulating layers formed between the first and upper patterned conductive layers, whereby the first conductive layers are isolated from one another and from the upper conductive layer, anda plurality of LEDs, including a plurality of distinct sets of one or more LEDs, each of the LEDs having first and second terminals and each being mounted over or adjacent to a corresponding one of the separated portions of the upper patterned conductive layer with a first terminal connected thereto, such that the sets of LEDs are interspersed along the linear arrangement,wherein the second terminals of each of the LEDs are connected to one of the patterned conductive layers such that the LEDs of each set are connected in series through the one or more first patterned conductive layers when passing under or adjacent to LEDs of the other sets that are connected to the corresponding one of the separated portions of the upper patterned conductive layer in the linear arrangement. 38. The array of LEDs of claim 37, wherein the number of distinct sets of one or more LEDs is greater than two, and wherein at least one of the first patterned conductive layers includes a plurality of horizontally separated, non-connected sections. 39. The array of LEDs of claim 37, wherein each of the sets of LEDs emits a different of color light. 40. The array of LEDs of claim 37, wherein the array is a two-dimensional array formed of a plurality of linear arrangements of LEDs, one of which is the linear arrangement formed by the plurality of LEDs. 41. The array of LEDs of claim 37, wherein the substrate is formed of an electrically insulating material. 42. The array of LEDs of claim 37, wherein the substrate is conductive and the circuit board further includes a lower insulating layer formed over the substrate, over which the first patterned conductive layers are formed. 43. The array of LEDs of claim 37, wherein the plurality of LEDs are mounted on the corresponding portion of the upper patterned conductive layer and have a vertical type LED structure. 44. The array of LEDs of claim 37, wherein the plurality of LEDs are mounted adjacent to the corresponding portion of the upper patterned conductive layer and have a horizontal type LED structure. 45. The array of LEDs of claim 37, wherein each of the plurality of LEDs is die-bonded to the corresponding portion of the upper patterned conductive layer. 46. The array of LEDs of claim 37, wherein the number of first patterned conductive layers is one, the number of distinct sets of LEDs is two, and the LEDs are connected to the first patterned conductive layer such that the LEDs of each set are connected in series through the first patterned conductive layer under the LEDs of the other set. 47. The array of LEDs of claim 46, wherein the LEDs of the two sets alternate in the linear arrangement.