Blue Phase Liquid Crystal Pixel Driving Circuit Power Reduction
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Solution Overview
Problem
Blue phase liquid crystal panels face high power consumption due to high driving voltage requirements and suffer from data signal loss caused by poor threshold voltage compensation in conventional 3T1C circuit structures, leading to flickering and reduced product quality.
Innovation Solution
A pixel driving circuit with a 4T2C structure, including transistors T1 to T4, a bootstrap capacitor Cbt, a storage capacitor Cst, and a light-emitting element D, where the fourth transistor T4 and storage capacitor Cst provide a constant driving current, reducing data signal voltage and compensating for threshold voltage issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage greater than 30V is applied to drive blue phase liquid crystal molecules, then the liquid crystal molecules can be effectively driven, but the power consumption increases exponentially
Solution Approach 1:
The patent divides the driving voltage function into two parts: a high voltage component (30V+) stored in the storage capacitor to drive blue phase liquid crystal molecules, and a low voltage data signal component used for control. This segmentation allows the high voltage to be applied only when needed for molecular switching, while normal operation uses lower voltages, thereby reducing overall power consumption while maintaining driving effectiveness.
2Device complexity
If a conventional 3T1C circuit structure is used, then the device complexity is lower, but the threshold voltage compensation effect is poor causing data signal loss and screen flicker
Solution Approach 1:
The patent segments the circuit into distinct functional modules: transistors T1-T4 for switching and control, capacitor C11 for threshold voltage compensation, and capacitor C12 for data signal storage. This modular segmentation allows each component to perform its specific function optimally, with C11 dedicated to compensation and C12 to signal storage, thereby improving overall circuit reliability without excessive complexity.
Solution Approach 2:
The patent introduces an intermediate capacitor C11 that acts as a mediator between the data signal input and the liquid crystal driving output. This capacitor specifically compensates for threshold voltage variations, serving as an intermediary element that stabilizes the driving voltage and prevents data signal loss, thereby improving reliability without significantly increasing complexity.
3Use of energy by moving object
If the data signal voltage is reduced to 10V, then the power consumption is reduced, but the ability to drive blue phase liquid crystal molecules effectively is compromised
Solution Approach 1:
The patent applies preliminary action by pre-charging the storage capacitor C12 with the full high voltage (30V+) before the actual display operation. This allows the capacitor to store the necessary high voltage energy in advance, so that during normal operation, the liquid crystal molecules can be driven effectively using the stored voltage, while the data lines only need to supply low voltage control signals, thereby reducing power consumption without compromising driving capability.
Data Source
AI summary
A pixel driving circuit, a method of driving the pixel driving circuit, and a display panel. The pixel driving circuit includes a first transistor T1, a second transistor T2, a third transistor T3, a fourth transistor T4, a bootstrap capacitor Cbt, a storage capacitor Cst, and a light-emitting element D.