Monolithic LED Display with Nanorod Arrays and Vertical Electrodes
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Solution Overview
Problem
Conventional full-color light-emitting diode (LED) displays face challenges in manufacturing complexity, high costs, and unsatisfactory performance due to the difficulty in transferring and integrating red, green, and blue light-emitting diodes on large substrates, as well as inefficiencies in emitting efficiency and brightness.
Innovation Solution
The use of self-assembled GaN nanorod arrays on Si substrates as templates for growing strain-free InGaN/GaN nanorod heterostructures, enabling the creation of monolithic, phosphor-free white LEDs with polarized full-color emissions by embedding InGaN nanodisks within GaN nanorods, which improves light mixing and reduces electron overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If red, green, and blue light-emitting diodes are grown on separate substrates and transferred to a display substrate, then full-color display capability is achieved, but manufacturing complexity and cost increase significantly due to the vast number of transfers required
Solution Approach 1:
The patent combines multiple light-emitting diodes (red, green, and blue) onto a single substrate, eliminating the need for separate substrates and complex transfer processes. This merging approach maintains full-color display capability while significantly simplifying the manufacturing process by reducing the number of transfer operations from millions to a manageable scale.
Solution Approach 2:
The invention creates a universal substrate that can accommodate and integrate multiple types of light-emitting diodes with different colors (red, green, blue) simultaneously. This multi-functional substrate serves as a common platform for all color channels, replacing the conventional approach of requiring separate specialized substrates for each color type.
2Productivity
If InGaN-based or AlGaInP-based light-emitting diodes are produced on large-diameter substrates, then production efficiency improves, but manufacturing precision deteriorates due to difficulty in producing on substrates larger than 2 or 3 inches
Solution Approach 1:
The patent segments the large substrate into multiple smaller active regions or modules where light-emitting diodes are grown. This segmentation allows precise control over each segment while maintaining the overall large substrate size for high productivity. The segmented approach enables better manufacturing precision by breaking down the challenging large-substrate process into manageable zones.
3Reliability
If wire-bonding steps are used to electrically connect light-emitting diodes with the printed-circuit board, then electrical connectivity is achieved, but device complexity and manufacturing time increase
Solution Approach 1:
The patent merges the electrical connection function into the substrate itself by integrating conductive structures directly onto the substrate during the light-emitting diode formation process. This eliminates the need for separate wire-bonding steps, maintaining reliable electrical connectivity while reducing manufacturing complexity and process time.
4Ease of operation
If conventional hybrid approaches are used for LED display configuration, then display functionality is achieved, but emitting efficiency and brightness remain unsatisfactory
Solution Approach 1:
The patent applies local quality optimization by carefully designing the substrate structure, electrode configuration, and light-emitting diode arrangement to enhance emitting efficiency and brightness in specific regions. This includes optimizing the local electrical and optical environment for each light-emitting diode to maximize light output and 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
This approach results in high-brightness, drive-current-insensitive white LEDs with improved color rendering and efficiency, overcoming the efficiency droop phenomenon at high current densities, and allows for scalable production on Si substrates with enhanced flexibility in emitter design.
Implementation Method 1
Each of the first, second, and third light-emitting diodes comprises: a first electrode; a first doped nanorod in ohmic contact with the first electrode
Implementation Method 2
forming a first active light-emitting region on each of a plurality of first top surfaces of the first doped nanorods
Implementation Method 3
The use of self-assembled GaN nanorod arrays on Si substrates as templates for growing strain-free InGaN/GaN nanorod heterostructures
Implementation Method 4
growing strain-free InGaN/GaN nanorod heterostructures
Data Source
AI summary
This invention relates light-emitting diode displays with simple structure and fabricating method as well as excellent efficiency. In an embodiment, the display features a nanorod LED array arranged on a substrate and divided into a first, second, and third sub-pixels. Two electrodes are preferably arranged in a vertical configuration for driving the sub-pixels. In another embodiment, a method features the sub-pixels for emitting multi-primary colors being formed on a conductive substrate and thus simplifies the steps.