Micro-LED Brightness Control via Segmented Electrodes
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Solution Overview
Problem
Conventional LEDs face challenges in controlling brightness due to nonlinear current density versus voltage characteristics, leading to issues with brightness uniformity and efficiency, especially under varying ambient light conditions.
Innovation Solution
A micro-light-emitting diode (micro-LED) design featuring a first and second type semiconductor layer, a dielectric layer with openings, and electrodes that allow independent control of current paths and electric potentials, enabling continuous and linear control of brightness across a wide dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional LEDs are used with wide operating current density range, then brightness dynamic range is extended, but brightness uniformity deteriorates due to nonlinear J-V characteristics
Solution Approach 1:
The patent divides the single LED structure into multiple independently controllable micro-LEDs arranged in an array. Each micro-LED has its own control electrode, allowing independent current control. This segmentation enables the system to achieve wide brightness dynamic range by activating different numbers of micro-LEDs while maintaining brightness uniformity by controlling each micro-LED within its optimal current density range.
Solution Approach 2:
The patent implements dynamic control of current distribution across the micro-LED array by applying different voltages to different control electrodes. This dynamic control allows the system to adapt brightness levels and uniformity in real-time, optimizing performance across the full brightness range by adjusting which micro-LEDs are active and at what current levels.
2Illumination intensity
If current density is increased to improve brightness output, then brightness intensity is improved, but conversion efficiency deteriorates due to thermal issues
Solution Approach 1:
By segmenting the LED into multiple micro-LEDs, the patent distributes the total current load across multiple devices. This allows the system to achieve high brightness intensity by activating more micro-LEDs rather than increasing current density in individual micro-LEDs, thereby maintaining conversion efficiency while improving overall brightness output.
Solution Approach 2:
The patent combines multiple micro-LEDs into a single display element where their light outputs are merged. This merging allows the system to achieve high brightness intensity through additive light output from multiple efficient micro-LEDs operating at optimal current densities, rather than relying on a single micro-LED operating at high current density where efficiency would deteriorate.
3Ease of operation
If voltage is increased to overcome threshold and enable current flow, then LED turns on, but brightness control becomes difficult due to exponential current increase
Solution Approach 1:
The patent segments the current control into multiple independent control electrodes, each managing a subset of micro-LEDs. This segmentation transforms the difficult problem of controlling a single exponential current-voltage relationship into multiple simpler control relationships, enabling precise brightness control by adjusting the voltage on each control electrode independently.
Solution Approach 2:
The patent applies partial action by activating only the necessary number of micro-LEDs to achieve the desired brightness level, rather than controlling all micro-LEDs at full current. This approach simplifies brightness control by using a subset of the available micro-LEDs, reducing the complexity of voltage control while maintaining ease of turn-on for the active elements.
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 design enhances brightness control and efficiency by allowing independent current generation and control, reducing non-radiative recombination, and minimizing side surface leakage, resulting in improved brightness uniformity and extended dynamic range.
Implementation Method 1
an active layer 150. The active layer 150 is disposed between the first type semiconductor layer 110 and the second type semiconductor layer 120
Data Source
AI summary
A micro-light-emitting diode (micro-LED) includes a first type semiconductor layer, a second type semiconductor layer, a dielectric layer, and electrodes. The second type semiconductor layer is disposed on or above the first type semiconductor layer. The dielectric layer is disposed on the second type semiconductor layer. The dielectric layer includes openings therein to expose parts of the second type semiconductor layer. The electrodes partially are disposed on the dielectric layer and respectively electrically coupled with the exposed parts of the second type semiconductor layer through the openings of the dielectric layer, in which the electrodes are separated from each other.