Liquid Crystal Display Voltage Control Circuit for Charge Discharge
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Solution Overview
Problem
Liquid crystal display devices face issues with burn-in and flicker phenomena due to residual electric charges when the power source is abruptly cut off, particularly in portable devices using the Fringe Field Switching (FFS) mode, as the existing solutions are complex and inefficient in discharging these charges.
Innovation Solution
A liquid crystal display device configuration that includes a voltage control circuit with a diode, switching element, and short-circuit element to rapidly change the non-selection potential to a rise area of the thin film transistor during power source cut-off, ensuring effective discharge of electric charges between pixel and common electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liquid crystal display device uses a normal configuration without special voltage control circuitry, then the device structure remains simple, but electric charges remain between pixel electrodes and common electrode after power cut-off causing burn-in and flicker phenomena
Solution Approach 1:
The voltage control circuit is activated in advance when power cut-off is detected, rapidly changing the non-selection potential to the rise area before the harmful effect (burn-in/flicker) can occur. This preliminary action ensures electric charges are discharged effectively without requiring complex continuous monitoring systems.
Solution Approach 2:
The voltage control circuit acts as an intermediary between the power supply system and the liquid crystal display panels. It includes a diode connected between the non-selection potential supply terminal and ground, and a switching element that mediates the potential change to achieve rapid discharge while maintaining simple overall device structure.
2Reliability
If existing solutions are used to discharge electric charges, then burn-in and flicker can be prevented, but the solutions are complex and inefficient
Solution Approach 1:
The invention extracts only the essential function needed for charge discharge by using a minimal voltage control circuit with a diode and switching element. This extracted solution achieves effective discharge without incorporating unnecessary complex circuitry that would exist in prior art solutions.
Solution Approach 2:
The voltage control circuit changes the non-selection potential parameter rapidly to the rise area when power cut-off is detected. This parameter change enables effective discharge of electric charges through the pixel electrode, achieving reliable operation with a simple circuit configuration rather than complex systems.
3Reliability
If the non-selection potential is not rapidly changed during power cut-off, then the circuit configuration can be simple, but electric charges cannot be discharged effectively causing potential difference between common electrode and pixel electrode
Solution Approach 1:
The voltage control circuit performs preliminary action by rapidly changing the non-selection potential to the rise area immediately when power cut-off is detected. This ensures electric charges are discharged effectively before potential differences can cause burn-in or flicker, achieving reliable charge discharge with minimal circuit complexity.
Data Source
AI summary
Disclosed herein is a liquid crystal display device having first and second substrates disposed to face each other so as to hold a liquid crystal layer therebetween, and a gate potential creating circuit for outputting a selection potential and a non-selection potential, scanning lines, signal lines, thin film transistors formed so as to correspond to intersection portions between the scanning lines and the signal lines, respectively, pixel electrodes electrically connected to the thin film transistors, respectively, and a gate control circuit for switching the selection potential and the non-selection potential supplied from the gate potential creating circuit over to each other, thereby supplying one of the selection potential and the non-selection potential to corresponding ones of the thin film transistors through corresponding one of the scanning lines being formed on the first substrate, and a common electrode being formed either on the first substrate or the second substrate.