Pixel Driving Circuit Charge Redistribution for LCD Color Washout

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Solution Overview

Problem

Current liquid crystal display technologies with wide viewing angles suffer from color washout issues due to insufficient electrical field intensity for larger electrode pitches, limiting transmittance and effective correction of color washout at side views.

Innovation Solution

A pixel driving circuit with a specific configuration of switches, capacitors, and a driving method that redistributes charges between data lines and scan lines to increase the voltage difference across liquid crystal capacitors, enabling a stronger electrical field for larger electrode pitches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a wide electrode pitch is used to correct color washout, then the viewing angle is improved, but the transmittance deteriorates due to insufficient electrical field intensity

Engineering Contradiction:

Improveviewing angleVSAvoidtransmittance

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The pixel is divided into two subpixels with different electrode pitches (first subpixel with first electrode pitch, second subpixel with second electrode pitch). This segmentation allows each subpixel to be optimized for different viewing angles, with the first subpixel providing narrow viewing angle correction and the second subpixel providing wide viewing angle correction, thereby resolving the contradiction between viewing angle and transmittance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the pixel (first subpixel and second subpixel) are assigned different electrode pitches tailored to their specific viewing angle requirements. The first subpixel uses a first electrode pitch optimized for its viewing angle range, while the second subpixel uses a second electrode pitch optimized for wide viewing angles, allowing each local region to achieve optimal transmittance for its intended function.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If a wide electrode pitch is used, then color washout is corrected, but the driving voltage requirement increases beyond integrated circuit output capability

Engineering Contradiction:

Improvecolor washout correctionVSAvoiddriving voltage

Core Design Contradiction:

Adaptability or versatilityVSPower

Solution Approach 1:

The pixel is segmented into two subpixels with different electrode pitches, allowing the use of lower driving voltages for the wide electrode pitch subpixel while maintaining sufficient electrical field intensity. This segmentation enables color washout correction without requiring excessively high driving voltages that would exceed integrated circuit output capabilities.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrode pitch parameter is changed between the two subpixels, with the second subpixel using a wider electrode pitch for color washout correction. This parameter change is accompanied by adjusted driving voltages that remain within integrated circuit output capabilities, achieving the desired color correction without excessive power requirements.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If multiple groups of electrode pitches are designed, then wide viewing angle is achieved, but the device complexity increases

Engineering Contradiction:

Improvewide viewing angleVSAvoidelectrode pitch configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pixel is divided into two subpixels with different electrode pitches, providing a simplified approach to achieving wide viewing angles compared to multiple groups of electrode pitches. This binary segmentation reduces the complexity of electrode pitch configuration while still enabling effective color washout correction across different viewing angles.

Inventive Principle:

Principle #1Segmentation

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

This configuration enhances transmittance and corrects color washout at side views by maintaining a higher voltage difference across liquid crystal capacitors, improving the performance of wider electrode pitches.

Implementation Method 1

liquid crystal display devices... liquid crystal capacitors... tilt degrees of liquid crystals depends on the electrical field intensity

Methodology Applied

Scientific EffectLiquid crystal effect: Liquid Crystals

Implementation Method 2

a liquid crystal capacitor, a first capacitor, a second capacitor, a first storage capacitor, a second storage capacitor

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS8842062B2Pixel driving circuit, driving method thereof, and pixel matrix

Publication Date: 2014.09.23 AU OPTRONICS CORP

AI summary

A pixel driving circuit is electrically coupled between a first data line and a second data line and between a first scan line and a second scan line, and includes a first switch, a second switch, a third switch, a fourth switch, a liquid crystal capacitor electrically connected between the first switch and the second switch, a first capacitor electrically connected to the first switch, a second capacitor electrically connected to the second switch, a first storage capacitor, a second storage capacitor and at least one switching unit. The first storage capacitor is electrically connected to the third switch and supplied by a reference voltage. The second storage capacitor is electrically connected to the fourth switch and supplied by the reference voltage. The at least one switching unit is used for redistributing charges in the pixel driving circuit.