Stacked LED Light Emitting Structure for Red Efficiency and Isolation
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Solution Overview
Problem
The existing light emitting diode (LED) structures face issues such as low red-light efficiency, equipment contamination, and operation efficiency degradation when forming red AlGaInP LEDs followed by green or blue GaN LEDs, along with challenges in aligning polarization and preventing short-circuits in ultra-fine electrode structures.
Innovation Solution
A display device with a stacked light emitting structure where red-light emitting elements are positioned on top as separate chips, using insulating layers to connect electrodes, and removing metal electrodes from the light emitting body to improve efficiency and prevent short-circuits, while using a wiring structure to facilitate electrode arrangement and control polarization alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If red AlGaInP LED is formed first and then green or blue GaN LED is formed, then red light emitting function is achieved, but equipment contamination and operation efficiency degradation occur
Solution Approach 1:
The patent divides the light emitting device into separate red LED chip and blue LED chip modules that are assembled together. This segmentation allows independent manufacturing of red and blue LEDs without cross-contamination, while still achieving combined light emitting functionality. The red LED chip is mounted on a first substrate and the blue LED chip on a second substrate, with electrical connections established through conductive adhesives or wires.
Solution Approach 2:
The patent transitions from a planar integration approach to a three-dimensional stacked configuration. The red LED chip is positioned on the first substrate, and the blue LED chip is mounted on top of it, creating a vertical arrangement. This dimensional change enables independent processing of each chip type while maintaining compact form factor, solving the equipment contamination issue.
2Ease of operation
If metal electrodes are disposed inside the LED for electrical connection, then electrical connection between upper and lower electrodes is achieved, but short circuit between p-n regions may occur
Solution Approach 1:
The patent introduces an insulating layer as an intermediary between the metal electrode and the semiconductor layers. This insulating layer is formed on the inner wall of the via hole, preventing direct contact between the metal electrode and the p-n regions, thereby eliminating the short circuit risk while maintaining electrical connection functionality through the insulated electrode structure.
3Reliability
If insulating layer is formed on inner wall of via hole in ultra-fine structure, then short circuit prevention is achieved, but electrical connection between upper and lower electrodes becomes difficult
Solution Approach 1:
The patent applies local quality by forming the insulating layer only on the inner wall surface of the via hole, while leaving the bottom and top openings clear for electrical connection. This localized application of insulation provides short circuit prevention at critical interfaces without compromising the electrical connectivity pathways, achieving both reliability and operability in ultra-fine structures.
4Ease of manufacture
If etching is performed for forming electrodes, then electrode structure is created, but damage on etched surface occurs causing dangling bond and light efficiency decrease
Solution Approach 1:
The patent performs preliminary surface treatment and passivation steps before and after the etching process to prevent damage and dangling bond formation. By preparing the surface in advance and applying protective layers subsequently, the etching process can be completed while minimizing light efficiency degradation from surface damage.
5Volume of moving object
If stacked structure is formed for red, green and blue light emitting elements, then space utilization is improved, but polarization alignment becomes difficult
Solution Approach 1:
The patent segments the multi-color light emitting device into separate red LED chip and blue LED chip modules, each with its own polarization characteristics. This segmentation allows independent optimization and alignment of polarization for each chip type, simplifying the overall polarization control compared to attempting to align multiple colors within a single integrated structure.
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 configuration enhances red-light efficiency, prevents equipment contamination, improves operation efficiency, and reduces the risk of short-circuits, while allowing for better polarization control and alignment in stacked LED structures.
Implementation Method 1
light emitting diodes (LEDs) are well known light emitting elements for converting an electrical current to light
Data Source
Figure 1
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Figure 3(a)~3(c)
AI summary
A display device having a light emitting structure may include first light emitting structures stacked on a first insulating layer on top of a driving panel, second light emitting structures stacked in alignment with the first light emitting structures on a second insulating layer on top of the first light emitting structures, and light emitting elements stacked on a third insulating layer on top of the second light emitting structures to be spaced apart from centers of the second light emitting structures. Each of the light emitting elements includes a p-electrode and an n-common electrode, and the p-electrode of the light emitting element may be connected to one of p-electrodes of the driving panel through an insulating structure, in which the first to third insulating layers are vertically connected.