Pre-rotated overmoulded bidirectional spreading lens for stretched leadframe architecture
View Patent ↗A method for manufacturing a solid state light-emitting device (LED) lighting apparatus includes forming a leadframe assembly with a group of leadframes connected in series by folded interconnects, mounting LEDs on the leadframes, disposing optical elements about the LEDs, and stretching the leadframe assembly so the interconnects unfold to space apart the LEDs. Disposing the optical elements includes orienting the optical elements so the optical elements provide a predetermined light pattern after stretching the leadframe assembly.
1. A method for manufacturing a solid state light-emitting device (LED) lighting apparatus, comprising:
forming a leadframe assembly comprising:
leadframes spaced apart at a first pitch, each leadframe comprising one or more pads; and
interconnects in an initial folded state, each interconnect linking two adjacent leadframes;
mounting LEDs on the leadframes;
disposing bidirectional spreading lenses about the LEDs, each bidirectional spreading lens having a spreading axis and a null axis perpendicular to the spreading axis, each bidirectional spreading lens directing more light in opposite directions along the spreading axis than the null axis; and
stretching the leadframe assembly so the interconnects unfold to space apart the LEDs at a second pitch greater than the first pitch;
the spreading axis being aligned with a stretch axis along the length of the stretched leadframe assembly after the leadframe assembly is stretched.
2. The method of claim 1 , wherein:
disposing the bidirectional spreading lenses further comprises angling the spreading axis relative to a pull axis before the leadframe assembly is stretched; and
the method further comprises determining an angle between the spreading axis and the pull axis based on a geometry of the leadframe assembly and a final length of the stretched leadframe assembly.
3. The method of claim 1 , wherein:
disposing the bidirectional spreading lenses further comprises angling the spreading axis relative to a row axis passing through the LEDs on the leadframes before the leadframe assembly is stretched; and
the method further comprises determining an angle between the spreading axis and the row axis based on a geometry of the leadframe assembly and a final length of the stretched leadframe assembly.
4. The method of claim 1 , wherein disposing the bidirectional spreading lenses comprises mounting the bidirectional spreading lenses on the LEDs or molding the bidirectional spreading lenses directly on the LEDs.
5. The method of claim 1 , wherein forming the leadframe assembly further comprises forming sacrificial ties that connect the interconnects and the leadframes, and the method further comprises trimming the sacrificial ties after mounting the LEDs and disposing the bidirectional spreading lenses.
6. The method of claim 1 , further comprising fixing the stretched leadframe assembly relative to reflectors.
7. The method of claim 6 , further comprising, for each gap between two adjacent reflectors from the reflectors, fixing an insulating strip over the gap.
8. The method of claim 1 , wherein the LEDs are prepackaged light-emitting diodes or naked light-emitting diode dice.
9. The method of claim 6 , further comprising:
inserting the stretched leadframe assembly and the reflectors into a transparent tube; and
mounting bi-pin connectors to ends of the transparent tube.