LED Array Contact Layout to Reduce Optical Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LED arrays face challenges such as contact with the fabrication substrate, optical absorption, and the appearance of a dark grid due to metal n-contacts, which affect efficiency and aesthetics.
Innovation Solution
The proposed LED array configuration features a continuous n-doped layer spanning multiple LEDs, with n-contacts localized to peripheral regions and p-contacts to central regions, reducing optical absorption and electrical crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal n-contacts are used to contact the n-doped layer, then electrical conductivity is improved, but optical absorption increases causing a dark grid effect
Solution Approach 1:
The patent extracts the n-contact function from the central region where it would cause optical absorption, and relocates it to peripheral regions where it does not interfere with light emission. This separates the electrical contact function from the optical path, eliminating the dark grid effect while maintaining conductivity.
Solution Approach 2:
The patent transitions from a planar contact arrangement to a three-dimensional configuration where n-contacts are positioned at peripheral regions and extend through p-doped layers via vertical pathways. This spatial reorganization allows electrical contact without blocking optical paths in the central emission regions.
2Reliability
If n-contacts extend through p-doped layers and active regions, then contact with continuous n-doped layer is achieved, but electrical crosstalk between adjacent LEDs increases
Solution Approach 1:
The patent segments the p-doped layers into discrete regions for each LED, with n-contacts extending only through their respective p-doped layers. This segmentation creates electrical isolation between adjacent LEDs while maintaining contact to the continuous n-doped layer, preventing crosstalk.
Solution Approach 2:
The patent applies different contact configurations to different regions: n-contacts are localized to peripheral regions of each LED and extend vertically through local p-doped layers, while the continuous n-doped layer provides horizontal connectivity. This local differentiation achieves both electrical contact and isolation.
3Ease of manufacture
If a continuous n-doped layer spans multiple LEDs, then manufacturing complexity is reduced, but optical isolation between adjacent LEDs is compromised
Solution Approach 1:
The patent segments the semiconductor structure into discrete p-doped layers and active regions for each LED, while maintaining a continuous n-doped layer at the base. This segmentation provides optical isolation between LEDs while the continuous n-layer simplifies manufacturing through single-step formation.
Solution Approach 2:
The patent uses a three-dimensional configuration where the continuous n-doped layer exists in the vertical dimension as a base layer, while optical isolation is achieved through horizontal segmentation of p-doped layers and active regions. This dimensional separation reconciles manufacturing simplicity with optical isolation.
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 external quantum efficiency by minimizing optical absorption and improves the appearance by reducing the dark grid effect, while maintaining acceptable optical crosstalk levels.
Implementation Method 1
the active region being arranged for emitting light at a corresponding LED wavelength as a result of radiative recombination of charge carriers at the active region
Implementation Method 2
Each of the LEDs includes a corresponding n-doped semiconductor layer, a corresponding p-doped semiconductor layer, a corresponding active region therebetween
Data Source
AI summary
An n-doped semiconductor layer spans multiple LEDs of an array, in some cases the entire array. Corresponding p-contacts are localized on the p-doped semiconductor layer of each LED to only a central region of that LED and are electrically isolated from the p-contacts of adjacent LEDs. Corresponding n-contacts (i) are localized to only peripheral regions of the corresponding LEDs, (ii) extend through the p-doped layers and the active regions of adjacent LEDs to make contact with the continuous n-doped layer, and (iii) are electrically isolated from those p-doped layers and active regions. In some cases the nonzero combined thickness of the n-doped layer, p-doped layer, and the active region can be less than 5 μm.