LCD Grayscale Voltage Adjustment for Deformation Area Light Leakage

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Solution Overview

Problem

Liquid crystal displays (LCDs) using chip on glass (COG) technology face light leakage issues due to substrate deformation during bonding, which worsens at low grayscale levels, and existing solutions either increase brightness at the cost of contrast or increase production costs.

Innovation Solution

The LCD incorporates a grayscale voltage adjusting mechanism that outputs a second grayscale voltage to subpixels in deformation areas, reducing brightness to match non-deformation areas, and uses a simulation method to determine deformation sub-areas for uniform voltage application, thereby minimizing light leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If grayscale voltage is increased to compensate for light leakage in deformation areas, then brightness of deformation areas improves, but contrast ratio deteriorates

Engineering Contradiction:

Improvebrightness of deformation areaVSAvoidcontrast ratio

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent applies different grayscale voltages to different regions of the display panel. Specifically, deformation areas receive adjusted grayscale voltages (second grayscale voltage) while non-deformation areas receive standard grayscale voltages (first grayscale voltage). This local differentiation compensates for light leakage in deformation areas without affecting the contrast ratio of the entire panel, as only the affected regions are adjusted.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the grayscale voltage parameter specifically for subpixels located in deformation areas. By adjusting the voltage level (from first grayscale voltage to second grayscale voltage) in affected regions, the brightness is compensated to match non-deformation areas, thereby resolving light leakage issues without globally altering the contrast ratio.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If uniform grayscale voltage is applied to all subpixels, then manufacturing process is simplified, but light leakage in deformation areas cannot be compensated

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidbrightness uniformity

Core Design Contradiction:

Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent implements a dual voltage system where subpixels are categorized into deformation areas and non-deformation areas. The grayscale voltage output circuit outputs different voltage levels (first grayscale voltage for non-deformation areas, second grayscale voltage for deformation areas) based on the specific location and deformation characteristics of each subpixel region.

Inventive Principle:

Principle #3Local quality

3Illumination intensity

If grayscale voltage adjustment is applied to all subpixels, then brightness uniformity improves, but device complexity increases

Engineering Contradiction:

Improvebrightness uniformityVSAvoidvoltage adjustment mechanism

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

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 approach effectively reduces light leakage across the display panel by adjusting voltages to match brightness levels between deformation and non-deformation areas, maintaining contrast while avoiding increased production costs.

Implementation Method 1

The pixel electrode and the common electrode may be configured to form an electric field to drive liquid crystal molecules to rotate, so the transmittance of incident light can be controlled

Methodology Applied

Scientific EffectElectric field: Electric Field

Implementation Method 2

drive liquid crystal molecules to rotate, so the transmittance of incident light can be controlled

Methodology Applied

Scientific EffectLiquid crystal molecular rotation: Liquid Crystals

Data Source

PatentUS11580921B2Liquid crystal display and driving method to compensate a deformation area thereof

Publication Date: 2023.02.14 BOE TECHNOLOGY GROUP CO LTD

AI summary

A liquid crystal display (LCD) and a driving method thereof are disclosed. The LCD includes: an LCD panel, a grayscale voltage output portion and a grayscale voltage adjusting portion. The LCD panel includes a deformation area formed by bonding of a driver integrated circuit, and the deformation area includes a first subpixel. The grayscale voltage output portion is configured to output a first grayscale voltage to the first subpixel. The grayscale voltage adjusting portion is configured to adjust the first grayscale voltage into a second grayscale voltage, so that a brightness of the first subpixel at the second grayscale voltage is less than a brightness of the first subpixel at the first grayscale voltage.