Liquid Crystal Display Light-Shielding Layer Capacitance Balancing

Solution Overview

Problem

Wearable display devices face light leakage issues due to strong external light, which affects their operation and display quality, and the use of a metal light-shielding layer to mitigate this introduces variations in capacitance among pixel electrodes, leading to deteriorated drive performance.

Innovation Solution

A liquid crystal display device design featuring a light-shielding layer over the entire display area with strategically sized and positioned pixel electrodes and auxiliary capacitance electrodes, ensuring equal total capacitance among all electrodes to stabilize field-through voltages and prevent light leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a metal light-shielding layer is provided to eliminate light leakage, then light leakage is prevented, but capacitances formed between pixel electrodes and the light-shielding layer differ depending on pixel electrode area, causing drive performance variation

Engineering Contradiction:

Improvelight leakageVSAvoiddrive performance uniformity

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by providing auxiliary capacitance electrodes with different areas at different locations corresponding to pixel electrodes of different areas. Specifically, pixel electrodes with larger areas are paired with auxiliary capacitance electrodes with smaller areas, and vice versa, so that the total capacitance (main capacitance from pixel electrode + auxiliary capacitance) becomes substantially equal across all pixel electrodes, eliminating drive performance variation while maintaining light-shielding functionality

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the capacitance parameter by introducing auxiliary capacitance electrodes that compensate for the varying capacitances formed between pixel electrodes of different areas and the light-shielding layer. By adjusting the area of these auxiliary electrodes, the total capacitance is equalized across all pixels, stabilizing the drive performance while preserving the light-shielding layer's protective function

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If pixel electrodes have different areas to accommodate varying display requirements, then display flexibility is improved, but capacitances formed with the light-shielding layer vary, deteriorating drive performance

Engineering Contradiction:

Improvedisplay flexibilityVSAvoiddrive performance uniformity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by providing auxiliary capacitance electrodes with different areas at different locations corresponding to pixel electrodes of different areas. Specifically, pixel electrodes with larger areas are paired with auxiliary capacitance electrodes with smaller areas, and vice versa, so that the total capacitance (main capacitance from pixel electrode + auxiliary capacitance) becomes substantially equal across all pixel electrodes, eliminating drive performance variation while maintaining light-shielding functionality

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent achieves equipotentiality in terms of capacitance by equalizing the total capacitance values across all pixel electrodes through the auxiliary capacitance electrodes. This ensures that all pixel electrodes have substantially equal capacitance despite having different areas, thereby stabilizing the drive performance and voltage distribution across the display device

Inventive Principle:

Principle #12Equipotentiality

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 design effectively prevents light leakage and stabilizes the drive performance of semiconductor elements, maintaining good display quality even under strong external light conditions.

Implementation Method 1

The light leakage can be eliminated by providing a metal light-shielding layer facing the semiconductor elements

Methodology Applied

Scientific EffectLight shielding: Absorption (EM radiation)

Implementation Method 2

the capacitances formed between a plurality of pixel electrodes having different pixel areas and the metal light-shielding layer differ depending on the pixel electrode

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS9835900B2Display device

Publication Date: 2017.12.05 MAGNOLIA WHITE CORP

AI summary

According to one embodiment, a display device includes a first substrate, a second substrate and a liquid crystal layer. The first substrate includes a display area including a plurality of pixels, and a light-shielding layer. Each of the pixels includes first and second pixel electrodes having have different pixel areas, a first semiconductor element, a second semiconductor element, a first capacitance electrode connected to the first semiconductor element and forming a first auxiliary capacitance, and a second capacitance electrode connected to the second semiconductor element, forming a second auxiliary capacitance, and having an electrode area different from that of the first capacitance electrode.