Micro LED Pixel Circuit Comparator Brightness Control
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Solution Overview
Problem
Micro LED display technology faces significant color coordinate drift issues due to variations in current, leading to uneven brightness of primary colors, affecting the display effect, especially when switching between large and small currents during gray scale changes.
Innovation Solution
A pixel circuit with a comparator that outputs different control voltages based on the comparison between pixel voltage and reference voltage, controlling the drive transistor to adjust the light emitting period of Micro LEDs, ensuring consistent brightness across colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional drive circuits are used for Micro LED, then the circuit structure is simple, but color coordinate drift occurs due to current variations affecting brightness uniformity
Solution Approach 1:
The patent applies dynamic control by using a comparator to continuously monitor pixel voltage and dynamically adjust the drive transistor gate voltage accordingly. This dynamic feedback mechanism ensures that brightness remains uniform across different gray levels while maintaining a relatively simple circuit structure consisting of the comparator, drive transistor, and storage capacitor.
Solution Approach 2:
The patent implements feedback control through the comparator that compares the pixel voltage with a reference voltage and feeds back the comparison result to control the drive transistor. This feedback mechanism corrects for current variations and prevents color coordinate drift, achieving bright uniformity without significantly increasing circuit complexity.
2Duration of action of moving object
If the drive transistor remains continuously on, then the light emitting duration is extended, but color coordinate drift increases due to current variations
Solution Approach 1:
The patent employs periodic action by controlling the drive transistor to operate in discrete on/off cycles rather than continuously. The transistor is turned on only when the pixel voltage exceeds the reference voltage, creating periodic light emission that maintains color coordinate stability while achieving the required display duration through frame-rate operation.
Solution Approach 2:
The drive transistor's on/off state is dynamically controlled based on real-time voltage comparison. This dynamic control ensures that light emission occurs only during appropriate voltage conditions, preventing color coordinate drift while maintaining sufficient light emitting duration for display refresh rates.
3Manufacturing precision
If gray scale switching between large and small currents is implemented, then display resolution is improved, but brightness uniformity deteriorates due to color coordinate drift
Solution Approach 1:
The comparator provides continuous feedback control that monitors pixel voltage during gray scale transitions and adjusts the drive transistor accordingly. This feedback mechanism ensures that both large and small current states maintain accurate color coordinates, achieving display resolution through gray scale switching while preserving brightness uniformity.
Solution Approach 2:
The circuit dynamically adapts to different gray scale levels by adjusting the drive transistor control based on real-time voltage comparison. This dynamic response ensures that transitions between large and small currents maintain consistent color coordinates across all gray levels, achieving high display resolution with uniform brightness.
Data Source
AI summary
Disclosed includes an apparatus, a drive method, a display panel, and a display device. The apparatus may comprise a drive transistor, a light emitting device driven by the drive transistor and a comparator. The comparator may have a first input coupled to a pixel voltage, a second input coupled to a reference voltage, a first control terminal coupled to a first control voltage, a second control terminal coupled to a second control voltage, and an output coupled to a gate of the drive transistor. The comparator may be configured to output the first control voltage to the output during a first time period in which the pixel voltage is not smaller than the reference voltage and output the second control voltage to the output during a second time period in which the pixel voltage is smaller than the reference voltage.