ULH Pixel Circuit Resetting Liquid Crystal Molecules
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Solution Overview
Problem
The transmittance ratio in liquid crystal display panels using uniform lying helix (ULH) structure liquid crystals is reduced due to disordered liquid crystal molecule arrangements caused by rapid changes in electrical fields, affecting display clarity and user experience.
Innovation Solution
A pixel circuit and driving method that applies a horizontal electrical field to reset and re-arrange ULH structure liquid crystal molecules before driving, using a configuration with pixel electrodes, liquid crystal capacitors, and switches to manage voltages and signals during reset, charging, and emitting periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If different applied electrical fields are used to deviate optical axes of liquid crystal molecules during driving, then the response speed of liquid crystal cells is improved, but the arrangement of liquid crystal molecules becomes disordered and transmittance ratio is lowered
Solution Approach 1:
The patent applies a preliminary reset electrical field before the main driving electrical field to pre-align the liquid crystal molecules. This preliminary action (reset phase) prepares the liquid crystal molecules in a controlled state before the deviating electrical field is applied, preventing disordered arrangement and maintaining high transmittance ratio while still achieving quick response speed.
2Productivity
If quick changes in electrical field direction are applied to drive ULH structure liquid crystal, then the refreshing rate of display is improved, but liquid crystal molecules cannot timely respond and arrangement becomes disordered
Solution Approach 1:
The patent employs periodic electrical field application with distinct phases: a reset phase followed by a driving phase. This periodic action allows liquid crystal molecules to be realigned during the reset phase before each frame, ensuring they are properly oriented for the subsequent driving phase, thus maintaining stable arrangement even at high refreshing rates.
Solution Approach 2:
Before applying the main driving electrical field for each frame, the patent applies a preliminary reset electrical field to realign the liquid crystal molecules. This preliminary action ensures molecules are in a controlled state before rapid direction changes occur, enabling timely response to quick electrical field changes and maintaining arrangement stability during high-speed refreshing.
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 method effectively reduces the lowering of transmittance ratio by restoring liquid crystal molecules to their initial state, improving display clarity and maintaining high transmittance even during alternate electrical field changes.
Implementation Method 1
the uniform lying helix (ULH) structure liquid crystal exhibits properties such as a quick response time, a high transmittance ratio, and a low absorption rate
Implementation Method 2
the designer often apply different applied electrical fields to deviate optical axes of liquid crystal molecules
Data Source
AI summary
A pixel circuit and a driving method thereof are provided. The pixel circuit includes first to second pixel electrodes, first to third liquid crystal capacitors, a first storage capacitor and first to third switches. The first liquid crystal capacitor and the first storage capacitor locate between the first pixel electrode and a first common voltage. The second liquid crystal capacitor locates between the first and the second pixel electrodes. The third liquid crystal capacitor locates between the second pixel electrode and the first common voltage. The first switch has ends for receiving a data voltage and a scan signal and coupled to the first pixel electrode. The second switch has ends for receiving a second common voltage and a reset signal and coupled to the first pixel electrode. The third switch has ends for receiving a reset voltage and the reset signal and coupled to the second pixel electrode.