Voltage Calibration Circuit for LCD Flickering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flickering in liquid crystal display (LCD) monitors due to asymmetry in negative and positive liquid crystal molecule rotations caused by variations in parasitic capacitance during the manufacturing process, leading to inconsistent gray levels.
Innovation Solution
A voltage calibration circuit that includes a coupling voltage detection circuit to detect the coupling voltage generated by parasitic capacitance and a common voltage circuit to adjust the common voltage accordingly, ensuring symmetry and preventing flickering without the need for additional writing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If parasitic capacitance is reduced during manufacturing, then gray level consistency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements a feedback mechanism where the coupling voltage detection circuit continuously monitors the coupling voltage generated by parasitic capacitance, and the common voltage circuit adjusts the common voltage based on this feedback to maintain symmetry between positive and negative gray levels, thereby resolving the gray level inconsistency caused by parasitic capacitance variations
Solution Approach 2:
The voltage calibration circuit performs self-adjustment by detecting its own coupling voltage and automatically compensating for parasitic capacitance effects through common voltage adjustment, eliminating the need for external manual calibration or additional writing processes
2Reliability
If NVM is used to adjust common voltage, then flickering is reduced, but manufacturing time increases
Solution Approach 1:
The patent performs voltage calibration during the initial phase of LCD operation before normal display begins. The coupling voltage detection circuit detects the coupling voltage early, and the common voltage circuit pre-adjusts the common voltage to compensate for parasitic capacitance, eliminating flickering before it affects display quality and avoiding post-manufacturing writing processes
Solution Approach 2:
The patent skips the traditional post-manufacturing NVM writing process by implementing rapid voltage calibration during the initial operation phase. The system quickly detects coupling voltage and adjusts common voltage without requiring time-consuming writing operations, thereby reducing manufacturing time while maintaining flickering reduction effectiveness
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 solution actively adjusts the common voltage to maintain symmetry, reducing flickering and manufacturing time, and increasing throughput by detecting and compensating for parasitic capacitance-induced voltage differences during the initial phase of LCD operation.
Implementation Method 1
a coupling voltage VFD is generated by the parasitic capacitance
Implementation Method 2
After capacitive coupling, the voltages of the data lines D1-Dm are symmetric to the common voltage Vcom
Data Source
AI summary
The present disclosure provides a voltage calibration circuit. The voltage calibration circuit includes a coupling voltage detection circuit and a common voltage circuit. The coupling voltage detection circuit is used for detecting a coupling voltage in an initial phase and generating a compensation voltage according to the coupling voltage. The common voltage circuit is used for adjusting a common voltage according to the compensation voltage and outputting the common voltage to a display module in a display phase.