Gap engineering for flip-chip mounted horizontal LEDs
First Claim
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1. A light emitting device comprising:
- a light emitting diode die including spaced apart anode and cathode contacts that extend along a face thereof;
a mounting substrate including spaced apart anode and cathode pads on a surface of the mounting substrate, the light emitting diode die being flip chip mounted on the mounting substrate such that the anode contact is adjacent and conductively bonded to the anode pad and the cathode contact is adjacent and conductively bonded to the cathode pad to define a gap comprising a top gap that extends along the face between the spaced apart anode and cathode contacts and a bottom gap that extends along the surface of the mounting substrate between the spaced apart anode and cathode pads; and
an encapsulant on the light emitting diode die, wherein the encapsulant expands during heating thereof and enters the gap;
wherein the top gap has a first shape, width, and length that extends along the face of the light emitting diode die, the bottom gap comprises a portion that extends along the surface of the mounting substrate and under the face of the light emitting diode die, the portion of the bottom gap having a second shape, width, and length, and the first shape and length of the top gap are substantially the same as the second shape and length of the portion of the bottom gap;
wherein the spaced apart anode and cathode pads comprise curved facing surfaces so that the bottom gap comprises a curved portion, and the curved portion is at a location beyond the face of the light emitting diode die; and
wherein the gap has a geometric configuration that prevents a sufficient amount of the encapsulant from entering the gap such that expansion of the encapsulant that has entered the gap does not debond the light emitting device from the substrate, and the geometric configuration comprises the curved portion of the gap.
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Abstract
A horizontal LED die is flip-chip mounted on a mounting substrate to define a gap that extends between the closely spaced apart anode and cathode contacts of the LED die, and between the closely spaced apart anode and cathode pads of the substrate. An encapsulant is provided on the light emitting diode die and the mounting substrate. The gap is configured to prevent sufficient encapsulant from entering the gap that would degrade operation of the LED.
75 Citations
18 Claims
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1. A light emitting device comprising:
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a light emitting diode die including spaced apart anode and cathode contacts that extend along a face thereof; a mounting substrate including spaced apart anode and cathode pads on a surface of the mounting substrate, the light emitting diode die being flip chip mounted on the mounting substrate such that the anode contact is adjacent and conductively bonded to the anode pad and the cathode contact is adjacent and conductively bonded to the cathode pad to define a gap comprising a top gap that extends along the face between the spaced apart anode and cathode contacts and a bottom gap that extends along the surface of the mounting substrate between the spaced apart anode and cathode pads; and an encapsulant on the light emitting diode die, wherein the encapsulant expands during heating thereof and enters the gap; wherein the top gap has a first shape, width, and length that extends along the face of the light emitting diode die, the bottom gap comprises a portion that extends along the surface of the mounting substrate and under the face of the light emitting diode die, the portion of the bottom gap having a second shape, width, and length, and the first shape and length of the top gap are substantially the same as the second shape and length of the portion of the bottom gap; wherein the spaced apart anode and cathode pads comprise curved facing surfaces so that the bottom gap comprises a curved portion, and the curved portion is at a location beyond the face of the light emitting diode die; and wherein the gap has a geometric configuration that prevents a sufficient amount of the encapsulant from entering the gap such that expansion of the encapsulant that has entered the gap does not debond the light emitting device from the substrate, and the geometric configuration comprises the curved portion of the gap. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification