Micro-LED Optics and Stepped Mesa Layout for Low Cross-Talk
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Solution Overview
Problem
Fibre-optic communication systems face challenges in achieving high-density μLED arrays due to optical interference and cross-talk, which limits the number of communication channels per unit area.
Innovation Solution
The fabrication method involves epitaxial growth of semiconductor layers, selective etching to form a stepped mesa without sidewall bumps, and the application of nano-imprinted optics to focus and collimate light emission, reducing optical interference and allowing closer spacing of μLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If μLED density is increased to allow more communication channels per unit area, then channel capacity is improved, but optical interference and cross-talk increase
Solution Approach 1:
The patent applies local quality by creating asymmetric stepped mesa structures where different regions of the LED have different heights. This local structural variation directs light emission in specific directions, concentrating optical energy into targeted communication channels while minimizing spread to adjacent channels, thereby reducing cross-talk and optical interference even at high densities
Solution Approach 2:
The patent transitions from a conventional planar LED structure to a three-dimensional stepped mesa structure. By introducing vertical dimensionality with multiple height levels, the device achieves directional light control without increasing lateral footprint, enabling higher channel density while maintaining optical isolation between channels through spatial separation in the vertical dimension
2Ease of manufacture
If conventional LED fabrication processes are used, then manufacturing is simpler, but side-wall bumps form increasing device size and light emission from sides
Solution Approach 1:
The patent segments the LED structure into multiple discrete height levels forming stepped mesas. This segmentation is achieved through selective etching processes that create distinct terraces at different elevations. The segmented structure eliminates continuous side-wall bumps by replacing them with discrete stepped surfaces, reducing unwanted lateral light emission while maintaining manufacturing feasibility through standard semiconductor processing techniques
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 approach enhances μLED density and reduces cross-talk, enabling higher channel densities and efficient light extraction, facilitating scalable and efficient optical communication systems.
Implementation Method 1
The nano-imprinted optic may improve the efficiency with which light can be extracted from the light-emitting structure, by reducing losses caused by total internal reflection
Implementation Method 2
the nano-imprinted optic may reduce optical interference between nearby LEDs by focussing and/or collimating the emitted light
Implementation Method 3
the nano-imprinted optic may reduce optical interference between nearby LEDs by focussing and/or collimating the emitted light
Implementation Method 4
a lens obtainable by thermal reflow lithography arranged over the light-emitting structure. Thermal reflow lithography may allow a lens to be fabricated from materials with high refractive indices. This may reduce losses due to internal reflection
Implementation Method 5
Thermal reflow lithography may allow a lens to be fabricated from materials with high refractive indices
Data Source
AI summary
A method of manufacturing a light-emitting diode device comprises fabricating a light-emitting diode structure comprising an inorganic semiconductor; and fabricating an optic over the light-emitting diode structure using nano-imprint lithography. The method may further comprise, before fabricating the optic, forming a first lens on the light-emitting diode structure by thermal reflow lithography. The optic and first lens may improve the efficiency of the light-emitting diode device by reducing losses due to total internal reflection. Also provided are light emitting diode devices obtainable by the method.