Light source with improved life
View Patent ↗A light source has an attachment element attached to a hollow outer element. First and second leads extend through the attachment element. A light-emitting diode (“LED”) die is attached to a substrate portion of a lead. Elastomeric encapsulant disposed within the hollow outer element surrounds the LED die. The light source includes a chamber between the elastomeric encapsulant and the attachment element.
1. A light source comprising:
a hollow outer element;
an attachment element attached to the hollow outer element;
a first lead extending through the attachment element and having a substrate portion;
a second lead extending through the attachment element;
a light-emitting diode (“LED”) die attached to the substrate portion;
elastomeric encapsulant disposed within the hollow outer element so as to surround the LED die; and
a chamber disposed between the elastomeric encapsulant and the attachment element to accomodate expansion and contraction of the elestomeric encapsulant.
2. The light source of claim 1 wherein the attachment element comprises at least one of a thermoplastic and a thermosetting polymer.
3. The light source of claim 1 wherein the attachment element comprises molding compound molded around the first lead and around the second lead.
4. The light source of claim 1 wherein the LED die emits light having a wavelength shorter than about 570 nm.
5. The light source of claim 1 wherein the LED die includes a wavelength-converting overlay having a wavelength-converting material dispersed in a silicone polymer matrix.
6. The light source of claim 5 wherein the elastomeric encapsulant comprises a silicone polymer.
7. The light source of claim 1 wherein the elastomeric encapsulant comprises a silicone polymer.
8. The light source of claim 1 wherein the hollow outer element includes a step, the attachment element adjoining the step.
9. The light source of claim 1 wherein the hollow outer element includes a tapered inner wall and the attachment element includes a tapered outer wall adjoining the tapered inner wall.
10. The light source of claim 1 wherein the attachment element includes a plug portion disposed within the hollow outer element and a flange portion adjoining a rim of the hollow outer element.
11. The light source of claim 10 wherein the flange portion extends beyond an outer wall of the hollow outer element.
12. The light source of claim 1 wherein the leads extend along the attachment element so as to provide a surface-mount light source.
13. The light source of claim 1 wherein the chamber is air-filled.
14. The light source of claim 1 wherein the chamber is evacuated.
15. The light source of claim 1 wherein the attachment element includes a mechanical alignment feature.
16. The light source of claim 1 wherein the attachment element includes a hole for dispensing the elastomeric encapsulant into the hollow outer element.
17. The light source of claim 1 wherein the elastomeric encapsulant comprises a drop of elastomeric encapsulant surrounding the LED die and at least partially covering the substrate portion.