LED-based light source utilizing asymmetric conductors

摘要

A light source includes LED dies that are flip-chip mounted on a flexible plastic substrate. The LED dies are attached to the substrate using an asymmetric conductor material with deformable conducting particles sandwiched between surface mount contacts on the LED dies and traces on the substrate. A diffusively reflective material containing light scattering particles is used instead of expensive reflective cups to reflect light upwards that is emitted sideways from the LED dies. The diffusively reflective material is dispensed over the top surface of the substrate and contacts the side surfaces of the dies. The light scattering particles are spheres of titanium dioxide suspended in silicone. The light source is manufactured in a reel-to-reel process in which the asymmetric conductor material and the diffusively reflective material are cured simultaneously. A silicone layer of molded lenses including phosphor particles is also added over the mounted LED dies in the reel-to-reel process.

主权项

1. A light source comprising:
a light emitting diode (LED) die having a first surface, a second surface and a lateral boundary, wherein the second surface is disposed opposite the first surface, wherein the LED die has surface mount contacts on the first surface and emits light from the second surface, and wherein the surface mount contacts include a p-contact and an n-contact; a mounting substrate having a top surface; a plurality of connection traces on the top surface of the mounting substrate, wherein the connection traces include an n-trace positioned to underlie the n-contact and a p-trace positioned to underlie the p-contact; an asymmetric conductor material sandwiched between the surface mount contacts and the connection traces; and a diffusively reflective material disposed on the top surface of the mounting substrate only outside the lateral boundary of the LED die.