Display Sub-Pixel Bias Voltage Control for Leakage Current Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices operating in variable refresh rate (VRR) mode experience quality degradation due to temperature-dependent color abnormalities caused by leakage currents between sub-pixels, leading to image distortion and flickers.
Innovation Solution
The implementation of a display device with sub-pixels having different bias voltage levels applied to their transistors, which includes a driving transistor and a second transistor, to manage and minimize leakage currents, thereby stabilizing color output across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If variable refresh rate mode is implemented to reduce power consumption, then energy efficiency is improved, but temperature-dependent color abnormalities and image quality degradation occur
Solution Approach 1:
The patent applies local quality by assigning different bias voltage levels to different sub-pixels (red, green, blue) based on their specific leakage current characteristics. Each sub-pixel receives a customized bias voltage (e.g., higher voltage for red sub-pixels with higher leakage, lower voltage for blue sub-pixels with lower leakage) to compensate for temperature-dependent variations in their respective leakage currents, thereby maintaining uniform color output across the display panel under variable refresh rate operation.
2Device complexity
If same bias voltage is applied to all sub-pixels to simplify control, then device complexity is reduced, but leakage current differences cause color abnormalities
Solution Approach 1:
The patent implements local quality by differentiating bias voltage levels across different sub-pixel types. The control circuit is configured to provide a first bias voltage to red sub-pixels, a second bias voltage to green sub-pixels, and a third bias voltage to blue sub-pixels, where each voltage level is optimized for the specific leakage current characteristics of that sub-pixel type. This localized differentiation compensates for manufacturing variations and temperature effects while maintaining manageable control complexity through systematic voltage assignment.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the bias voltage parameter for each sub-pixel based on its type and operational conditions. The bias voltage is not fixed but is selectively changed according to the sub-pixel's leakage current characteristics, enabling precise control over current distribution and color output. This parameter optimization ensures that each sub-pixel operates within its optimal voltage range to minimize leakage current variations.
Data Source
AI summary
A display device in one example includes a first sub-pixel, a second sub-pixel, and a third sub-pixel, where each of the first sub-pixel, the second sub-pixel, and the third sub-pixel includes a driving transistor, a first transistor, and a second transistor. The driving transistor includes a gate electrode connected to a first node, a first electrode connected to a second node, and a second electrode connected to a third node, and provides a driving current to a light emitting diode. The first transistor includes a first electrode receiving a bias voltage, a second electrode connected to the second node, and a gate electrode to which a third scan signal is applied. The second transistor includes a first electrode connected to the third node, a second electrode connected to an anode of the light emitting diode, and a gate electrode to which an emission control signal is applied.