LED Package Structure With Black Matrix Coverage and Flat Bonding
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Solution Overview
Problem
Conventional light-emitting diode (LED) package structures face challenges in achieving flatness and reliability in the bonding process, particularly due to incomplete coverage by the black matrix, which leads to reduced contrast in LED displays.
Innovation Solution
A package structure that includes a substrate with conductive pads, a light-emitting diode, a photo imageable dielectric material, and a black matrix, where the photo imageable dielectric material supports adhesion between the light-emitting diode and the substrate, and the black matrix is designed to completely cover the conductive pads and light-emitting diode without slits, eliminating the need for extra heating processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a black matrix is used to shield reflective light from the conductive pad, then light contrast is improved, but the conductive pad cannot be completely covered due to large tolerance of exposure and development techniques
Solution Approach 1:
The patent applies preliminary action by forming a preliminary reflective light shielding structure (including photo imageable dielectric material and black matrix) before bonding the light-emitting diode. This preliminary structure pre-shields the conductive pad from reflective light, ensuring complete coverage without relying on post-bonding adjustments. The photo imageable dielectric material is patterned to extend beyond the light-emitting diode footprint, creating an overlapping region that guarantees full conductive pad coverage while maintaining manufacturing tolerance.
Solution Approach 2:
The patent extends the reflective light shielding structure into the lateral dimension by designing the photo imageable dielectric material and black matrix to laterally overlap with the light-emitting diode. This dimensional extension ensures that the conductive pad is completely covered in the planar view, eliminating the need for perfect alignment in the vertical dimension alone. The overlapping design in the lateral dimension compensates for exposure and development tolerances.
2Ease of manufacture
If conventional bonding process is used for light-emitting diode, then manufacturing simplicity is maintained, but flatness and reliability in bonding process deteriorate
Solution Approach 1:
The patent introduces a photo imageable dielectric material as an intermediary substance between the substrate and the light-emitting diode. This intermediary material fills the bonding interface, providing uniform adhesion and eliminating voids or air gaps that would compromise bonding reliability. The dielectric material acts as a mediator that transfers and distributes bonding forces uniformly, improving both flatness and reliability while maintaining process simplicity through integration with the reflective light shielding structure formation.
3Reliability
If extra heating process is added after bonding light-emitting diode, then curing of dielectric material is achieved, but manufacturing complexity and process time increase
Solution Approach 1:
The patent merges the bonding process and the dielectric material curing process into a single integrated step. The reflective light shielding structure formation and the light-emitting diode bonding are combined such that the dielectric material cures simultaneously with the bonding process, eliminating the need for a separate post-bonding heating step. This consolidation reduces manufacturing complexity and process time while ensuring complete curing of the dielectric material for reliable bonding.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the reliability and flatness of the package structure, preventing contrast reduction by ensuring complete coverage and eliminating bubbles, resulting in high contrast color performance for LED displays.
Implementation Method 1
the photo imageable dielectric material supports adhesion between the light-emitting diode and the substrate
Implementation Method 2
a black matrix is commonly used to shield reflective light from the conductive pad underlying the light-emitting diode
Data Source
AI summary
A package structure includes a substrate, a plurality of conductive pads, a light-emitting diode, a photo imageable dielectric material, and a black matrix. The substrate includes a top surface. The conductive pads are located on the top surface of the substrate. The light-emitting diode is located on the conductive pads. The photo imageable dielectric material is located between the light-emitting diode and the top surface of the substrate and between the conductive pads. An orthogonal projection of the light-emitting diode on the substrate is overlapped with an orthogonal projection of the photo imageable dielectric material on the substrate. The black matrix is located on the top surface of the substrate and the conductive pads.