Micro-LED Array Pixel Temperature Sensing via Forward-Voltage Feedback
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Solution Overview
Problem
Micro-LED arrays experience unacceptable color or intensity changes due to varying temperature across the die or substrate, leading to issues like color or light intensity banding, bright spots, or dark spots, which existing driving techniques fail to address effectively, especially in larger arrays with operational power and data management challenges.
Innovation Solution
A temperature monitor and control system measures bus voltage to determine LED forward voltage and corresponding temperature for each pixel, adjusting pixel array parameters such as current amplitude and pulse width modulation to compensate for temperature variations, using a control block to manage thousands or millions of individually addressable micro-LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If micro-LED arrays are used to achieve high brightness and energy efficiency, then display performance is improved, but temperature variations cause unacceptable color or intensity changes
Solution Approach 1:
The patent implements temperature sensing for each micro-LED pixel and uses feedback control to adjust drive current. The control circuit measures the actual temperature of each pixel and dynamically adjusts the drive current to compensate for temperature-induced color and intensity shifts, ensuring uniform display performance across varying operating conditions
Solution Approach 2:
The patent applies local quality control by individually monitoring and controlling the temperature and drive parameters of each micro-LED pixel rather than treating the entire array uniformly. Each pixel has its own temperature sensor and control circuitry, allowing localized compensation for temperature variations that would otherwise cause banding and non-uniformity
2Stability of the object's composition
If individual micro-LED control is implemented to achieve uniform display, then color consistency is improved, but device complexity increases
Solution Approach 1:
The patent segments the control system into modular pixel-level units, where each micro-LED pixel or small group of pixels has its own dedicated temperature sensor and control circuit. This segmentation allows independent control of each pixel's temperature compensation while maintaining overall system manageability through standardized modular units
Solution Approach 2:
The patent designs universal control circuits that can be replicated across the entire array, where each control unit performs multiple functions: temperature sensing, drive current generation, and temperature compensation. This multi-functionality reduces overall system complexity by eliminating the need for separate dedicated components for each function
3Stability of the object's composition
If temperature monitoring for each pixel is implemented, then color consistency is improved, but measurement and control difficulty increases
Solution Approach 1:
The patent implements self-service temperature monitoring where each micro-LED pixel's own electrical characteristics (forward voltage, current) are used as temperature indicators. The pixel essentially measures its own temperature through its operational parameters, eliminating the need for external complex temperature sensing systems and reducing measurement difficulty
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
The system ensures consistent light emission by compensating for temperature fluctuations, preventing color or intensity variations, and optimizing energy efficiency and operational performance in large micro-LED arrays.
Implementation Method 1
The control block can measure bus voltage to determine LED forward voltage and corresponding temperature for the first pixel
Implementation Method 2
adjustments to the pixel array based on the temperature are based on changes to at least one of pixel array supplied current amplitude and pulse width modulation
Data Source
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AI summary
A temperature monitor and control system for a pixel array includes a first driver connected to a first pixel connected to a bus by a first switch, a second driver connected to a second pixel connected to a bus by a second switch, and a control block including connection to the first and second switches. The control block turns on the first switch and turns off the second switch, measures bus voltage, determines an LED forward voltage shift of the first pixel and corresponding temperature shift for the first pixel based on the determined forward voltage shift, and adjusts a driving current for first pixel based on the determined temperature shift.