Micro-LED Pixel Current Sensing for Accurate Low-Gray Compensation
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Solution Overview
Problem
Micro-LED display devices face challenges in accurately compensating for differences in currents and mobilities of driving transistors, particularly at low gray levels where transistors operate in a subthreshold region, leading to inefficiencies and power consumption issues.
Innovation Solution
A micro-LED display device with a driver and timing controller that includes a sensor to detect current output through LEDs, convert it into voltage, and a converter to adjust the digital voltage, controlling the ON/OFF of driving transistors to compensate for current and mobility differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a diode connection scheme is used to control pixels, then the display device can operate with simple circuitry, but it is difficult to accurately compensate for the difference between currents of pixels, especially at low gray levels where transistors operate in subthreshold region
Solution Approach 1:
The pixel circuit is divided into multiple parallel transistors (first transistor and second transistor) with independent current control paths. This segmentation allows independent adjustment of current through each transistor to compensate for manufacturing variations and mobility differences, enabling accurate current compensation even at low gray levels where single-transistor schemes fail.
2Use of energy by stationary object
If the display device operates at low gray levels with transistors in subthreshold region, then power consumption is reduced, but current compensation accuracy deteriorates
Solution Approach 1:
The system dynamically adjusts the operating state of multiple transistors based on detected current variations. By controlling the ON/OFF states and current ratios of parallel transistors, the system maintains accurate current compensation across different gray levels, including the subthreshold region at low brightness, while optimizing power consumption according to the operating conditions.
3Power
If driving transistors are used to control pixel currents, then the display can achieve high luminance and efficiency, but differences in transistor mobilities cause current variations between pixels
Solution Approach 1:
A sensor is integrated into the pixel circuit to detect the actual current output of the light-emitting element. This feedback signal is used to adjust the current through the driving transistors, compensating for mobility variations and other non-ideal effects. The feedback mechanism enables precise current control while maintaining the high efficiency benefits of active driving transistors.
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 solution effectively reduces power consumption and improves accuracy in compensating for current and mobility variations among pixels, enhancing the performance and efficiency of the micro-LED display.
Implementation Method 1
a sensor for detecting current output through a LED in a first pixel of the plurality of pixels and converting the detected current into a voltage
Implementation Method 2
a converter for converting the converted voltage into a digital voltage
Implementation Method 3
controlling ON/OFF of at least one driving transistor among a plurality of driving transistors disposed in the first pixel, based on the converted digital voltage
Implementation Method 4
detecting current output through a LED in a first pixel
Data Source
AI summary
Disclosed are a micro-LED display device capable of compensating for a difference between currents of pixels. The micro-LED display device includes a display panel including a plurality of pixel areas and a driver disposed in each of the pixel areas to control an operation of a plurality of pixels disposed in each of the pixel areas; and a timing controller configured to control an operation of the driver disposed in each of the pixel areas, wherein the driver comprises: a sensor for detecting current output through a LED in a first pixel of the plurality of pixels and converting the detected current into a voltage; and a converter for converting the converted voltage into a digital voltage, wherein the driver is configured to control ON/OFF of at least one driving transistor among the plurality of driving transistors disposed in the first pixel, based on the converted digital voltage.