Micro-LED Diode Array Layout for Sidewall Current Limiting
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Solution Overview
Problem
Micro-LED displays face challenges in epitaxial chip and process efficiency, mass transfer techniques for large-scale production, and inspection and repair methods for quality control.
Innovation Solution
A diode array is designed with a substrate and light emitting diodes arranged in an array, featuring a stack of functional layers including semiconductor layers and a light emitting layer, with current limiting regions and electrodes configured to enhance efficiency and facilitate mass transfer and inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the size of the LED chip is reduced to achieve micro-LED displays, then the display resolution and integration are improved, but the external quantum efficiency is reduced due to non-radiative recombination at sidewalls and surfaces
Solution Approach 1:
The patent applies ion implantation to create a high-conductivity region at the LED sidewalls, converting the harmful non-radiative recombination at sidewalls into a beneficial low-resistance current path. This resolves the contradiction by transforming the sidewall defect (harmful) into a functional feature (beneficial) that simultaneously improves current distribution and reduces non-radiative losses.
Solution Approach 2:
The patent introduces a localized high-conductivity region through ion implantation at the LED sidewalls, creating non-uniform electrical properties in specific areas. This local modification allows the sidewalls to serve a dual function: maintaining structural integrity while providing enhanced current confinement and reduced non-radiative recombination, thus improving overall efficiency without changing the chip size.
2Productivity
If mass transfer technology is used to transfer micro-LEDs onto display substrates, then large-scale production is enabled, but the transfer accuracy and positioning precision are reduced
Solution Approach 1:
The patent pre-forms connection structures (such as metal pads or bonding features) on both the micro-LED array substrate and the display substrate before the transfer process. This preliminary preparation enables automated pick-and-place or direct bonding transfer methods to achieve high precision positioning at scale, resolving the contradiction between mass transfer productivity and positioning accuracy.
3Reliability
If inspection and repair methods are implemented for micro-LED quality control, then product reliability is improved, but the production time and process complexity are increased
Solution Approach 1:
The patent incorporates test structures and redundancy design during the micro-LED fabrication process, allowing for preliminary electrical and optical characterization before final assembly. This advance inspection enables early identification and sorting of defective devices, reducing the need for time-consuming post-assembly repair operations and resolving the contradiction between quality control and production efficiency.
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 diode array improves light emitting efficiency by reducing non-radiative recombination, facilitates mass transfer with enhanced current limiting regions, and enables effective inspection and repair processes, addressing key challenges in micro-LED technology.
Implementation Method 1
a light emitting layer located between the first semiconductor layer and the second semiconductor layer
Data Source
AI summary
A diode array includes a substrate and a plurality of light emitting diodes disposed on the substrate and arranged in an array. Each of the light emitting diodes includes a stack of functional layers includes a first semiconductor layer, a second semiconductor layer, and a light emitting layer located between the first semiconductor layer and the second semiconductor layer. At least one of the light emitting diodes includes a first current limiting region covering at least a portion of the first semiconductor layer, the light emitting layer or the second semiconductor layer; a first electrode electrically connected to the first semiconductor layer; and a second electrode electrically connected to the second semiconductor layer, wherein the first electrode and the second electrode are disposed at the same side of the first semiconductor layer.