LCD Drive Control for Polarity Bias and Flicker Suppression

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Solution Overview

Problem

Existing liquid crystal display devices that perform refresh in complete synchronization with image signal input are prone to display quality deterioration due to irregular polarity inversions of data voltage, which existing methods cannot effectively address.

Innovation Solution

A liquid crystal display device with a drive control circuit that includes a counter to count polarity bias, controlling the operations of image and scanning signal line drive circuits to adjust polarity bias within predetermined limits, and dynamically switch between synchronous and asynchronous drive systems to maintain optimal polarity balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If refresh is performed in complete synchronization with image signal input, then productivity is improved, but display quality deteriorates due to irregular polarity inversions

Engineering Contradiction:

Improverefresh synchronizationVSAvoiddisplay quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces a feedback mechanism where the polarity bias value is continuously counted and monitored. Based on this feedback, the drive control circuit dynamically adjusts the polarity inversion timing to maintain balanced polarity application, thereby preventing display quality deterioration while preserving synchronous refresh operation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent makes the polarity inversion timing dynamic rather than fixed. The drive control circuit adjusts the timing of polarity inversions based on the counted polarity bias value, allowing the system to adaptively maintain polarity balance during synchronous refresh operations, thus resolving the contradiction between synchronization and display quality.

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If pause drive is implemented to reduce power consumption, then use of energy is improved, but display quality deteriorates due to irregular polarity inversions

Engineering Contradiction:

Improvepower consumptionVSAvoiddisplay quality

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The polarity bias counting mechanism provides continuous feedback on polarity balance status. This feedback enables the drive control circuit to make informed decisions about when to invert polarity during pause drive operations, ensuring display quality is maintained even when refresh operations are suspended to reduce power consumption.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary counting of polarity bias values during active periods before pause periods occur. This preliminary action allows the system to plan and execute polarity inversions at optimal timing during pause drive, preventing polarity imbalance from causing display quality issues while maintaining energy savings.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If polarity inversion is performed irregularly, then adaptability is improved, but display quality deteriorates due to polarity bias

Engineering Contradiction:

Improvepolarity inversion flexibilityVSAvoiddisplay quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces dynamic control of polarity inversion timing based on the counted polarity bias value. Rather than using fixed or completely irregular inversion patterns, the system adaptively adjusts inversion timing to maintain polarity balance, thus preserving display quality while retaining operational flexibility.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of polarity inversion timing based on the polarity bias value. By dynamically adjusting this parameter according to the counted bias, the system maintains polarity balance and prevents display quality deterioration while preserving the ability to adapt to different operating conditions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12536974B2Liquid crystal display device for suppressing deterioration of display quality caused by polarity bias of data voltage and method of driving the same

Publication Date: 2026.01.27 SHARP DISPLAY TECHNOLOGY CORP

AI summary

A drive control circuit that controls operations of liquid crystal drive circuits (a gate driver and a source driver) is provided with a counter that counts a polarity bias value that represents polarity bias of a data voltage applied to liquid crystal capacitance. During a scan frame period in which the polarity bias value is greater than a predetermined upper limit at a start of input of one frame of the image signal, the drive control circuit controls operations of the liquid crystal drive circuits so that the polarity bias value becomes smaller. During a scan frame period in which the polarity bias value is smaller than a predetermined lower limit at the start of input of one frame of the image signal, the drive control circuit controls the operations of the liquid crystal drive circuits so that the polarity bias value becomes larger.