Micro-LED Amplitude Control for Power Efficiency
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Solution Overview
Problem
Conventional PWM dimming in micro-LED arrays results in inefficient power utilization and adverse heating effects due to mismatched current density and peak external quantum efficiency, leading to suboptimal light intensity control across thousands of pixels.
Innovation Solution
The system defines separate groups of LED pixels with distinct average currents, modulating amplitude and duty cycle to optimize power efficiency by aligning current density with peak external quantum efficiency, using a DAC module to adjust signals and maintain unchanged average pixel current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional PWM dimming is used to control micro-LED pixel brightness, then individual pixel control is achieved, but power efficiency deteriorates due to mismatched current density and peak external quantum efficiency
Solution Approach 1:
The patent segments the micro-LED array into multiple groups, where each group shares a common current amplitude signal. This segmentation allows independent optimization of current amplitude for different groups while maintaining individual pixel control through duty cycle modulation, thereby improving power efficiency without sacrificing control capability.
Solution Approach 2:
The patent applies local quality by allowing different current amplitude values for different groups of pixels based on their specific requirements. Each group can be optimized to operate near its peak external quantum efficiency point, ensuring that local power efficiency is maximized while maintaining overall system control.
2Device complexity
If conventional PWM dimming with fixed current amplitude is used, then control simplicity is maintained, but heating effects increase due to inefficient power utilization
Solution Approach 1:
The patent introduces dynamic current amplitude control where the amplitude can be adjusted for different pixel groups based on their brightness requirements. This dynamic adjustment allows the system to operate more efficiently, reducing wasted energy and consequently minimizing heating effects while maintaining manageable control complexity through grouped management.
3Device complexity
If duty cycle alone is used for brightness control, then control mechanism is simple, but power efficiency deteriorates due to inability to optimize current density
Solution Approach 1:
The patent adds another dimension to the control mechanism by introducing current amplitude modulation in addition to duty cycle control. This dual-dimensional approach (amplitude + duty cycle) enables optimization of current density for each pixel group, significantly improving power efficiency while keeping the control mechanism manageable through grouped management rather than full individual control.
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 power efficiency by optimizing current density for each group of pixels, reducing waste power usage and minimizing heating effects while maintaining image quality.
Implementation Method 1
A micro-LED array contains one or more arrays of thousands to millions of microscopic LED pixels that actively emit light
Implementation Method 2
EQE is a measure of the ratio of the number of photons emitted from the LED to the number of electrons passing through the device
Data Source
AI summary
A control system for an LED array relies on defining a first and a second group of separately addressed LED pixels, with the first group including pixels with an average current no less than the current at a Q point and a second group including pixels with an average current less than the current at a Q point. An amplitude signal provided to the first group of separately addressed LED pixels is selectively modulated, while providing a DC mode 100% duty cycle. An amplitude signal provided to the second group of separately addressed LED pixels is fixed, and a modulated duty cycle is provided.