Multi-Cell LED Structure With Floating Reflective Metal Layers
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Solution Overview
Problem
The existing light emitting diodes with multiple cells connected in series face challenges in heat dissipation and electrical reliability due to high electrical potential differences and insulation breakdown, leading to device failure, especially when measuring electrical characteristics.
Innovation Solution
A light emitting diode structure with a matrix arrangement of cells, ohmic reflection layers, and pad metal layers, where third pad metal layers are used to improve light efficiency and electrical reliability by reflecting light and electrically floating to prevent shorts, and bump pads are strategically placed for heat dissipation and insulation protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If bump pads are formed across multiple light emitting cells to improve heat dissipation, then heat dissipation characteristics are improved, but high electrical potential difference occurs between bump pads and electrodes causing insulation breakdown and electrical short
Solution Approach 1:
The patent divides the bump pad structure into multiple separate bump pads, each positioned over specific light emitting cells. This segmentation allows each bump pad to be electrically isolated from cells at different potentials, preventing electrical short while maintaining heat dissipation capability through distributed thermal pathways.
Solution Approach 2:
The patent applies different electrical connection configurations to different regions of the light emitting device. Specifically, bump pads are selectively connected to certain light emitting cells while remaining isolated from others, creating local electrical properties that prevent potential difference issues while maintaining overall heat dissipation performance.
2Measurement precision
If probes are pressed against bump pads to measure electrical characteristics, then reliable contact is achieved, but damage occurs to bump pads and insulation layer causing electrical short
Solution Approach 1:
The patent introduces an intermediary structure between the probe and the bump pad, specifically a protective insulation layer with openings that guides probe contact. This intermediary protects the bump pad from direct mechanical damage while ensuring reliable electrical contact for measurement through the controlled opening pathways.
Solution Approach 2:
The patent provides protective insulation layers that cover vulnerable areas before measurement or operation. These pre-applied protective layers cushion against potential probe damage to the bump pads and underlying insulation, preventing electrical short before they can occur during measurement procedures.
3Loss of energy
If a plurality of light emitting cells is connected in series to operate at high voltage and low current, then droop phenomenon is reduced, but device complexity increases requiring additional reflection structures between cells
Solution Approach 1:
The patent designs the bump pads and metal layers to serve multiple functions simultaneously. These structures provide both electrical connection between cells and light reflection in the regions between cells, eliminating the need for separate dedicated reflection structures and reducing overall device complexity while maintaining series connection benefits.
Solution Approach 2:
The patent merges the electrical connection function and light reflection function into a single integrated structure. The metal layers and bump pads that connect cells electrically also serve as reflection surfaces for light, combining two previously separate requirements into one unified structural element.
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
The proposed structure enhances light efficiency and electrical reliability by preventing electrical shorts and improving heat dissipation, allowing safe operation under high driving voltages while maintaining device integrity.
Implementation Method 1
a third pad metal layer disposed between the connectors, wherein the third pad metal layer covers a cell isolation region between the light emitting cells
Implementation Method 2
the flip-chip type electrode structure can dissipate heat using bump pads, thereby having favorable heat dissipation characteristics
Implementation Method 3
an insulation layer disposed under the bump pad. The insulation layer may be damaged, and thus, electrical short may be induced between the bump pad and a conductive metal layer disposed thereunder
Data Source
AI summary
A light emitting diode having a plurality of light emitting cells is provided. A light emitting diode according to an embodiment includes a reflection metal layer covering a region between light emitting cells, in which the reflection metal layer is disposed between connectors electrically connecting adjacent light emitting cells, and electrically insulated from a bump pad.