Liquid Crystal Display Pixel Structure with Floating Light-Shielding Pattern

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Solution Overview

Problem

The existing pixel structures in liquid crystal display panels face challenges in reducing cross talk and parasitic capacitance due to the proximity of the transparent pixel electrode and data line, which affects the aperture ratio and display brightness, and existing solutions like organic insulator films suffer from water absorption and poor adhesion issues.

Innovation Solution

A pixel structure is designed with a light-shielding pattern made of a second patterned conductive layer that partially overlaps the first data line section, increasing the distance between the pixel electrode and data line, and using contact plugs to electrically connect the data lines, while also shielding light leakage and optimizing parasitic capacitance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the transparent pixel electrode and data line are positioned closer to increase aperture ratio, then the aperture ratio is improved, but the parasitic capacitance between pixel and data line increases causing cross talk

Engineering Contradiction:

Improveaperture ratioVSAvoidparasitic capacitance and cross talk

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a light-shielding pattern as a floating metal layer positioned between the data line and pixel electrode in the vertical dimension. This third-dimensional structure provides electromagnetic shielding while maintaining the close horizontal spacing needed for high aperture ratio, effectively reducing parasitic capacitance without sacrificing display area.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The light-shielding pattern serves as an intermediary element between the data line and pixel electrode. This floating metal structure acts as an electromagnetic shield that intercepts and redirects electric field lines, preventing direct capacitive coupling between the data line and pixel electrode while allowing both components to remain in close proximity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the common line and data line are positioned closer to improve device layout, then the device complexity is reduced, but the parasitic capacitance between common line and data line increases causing cross talk

Engineering Contradiction:

Improvelayout complexityVSAvoidparasitic capacitance and cross talk

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The light-shielding pattern acts as an intermediary shielding structure between the common line and data line. This floating metal layer intercepts electric field interactions between these closely-spaced conductors, preventing parasitic capacitance formation while allowing the simplified close-layout configuration to be maintained.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If organic insulator film is used to reduce capacitance between data line and pixel electrode, then the capacitance effect is reduced, but the film suffers from water absorption, yellowing, and poor interface adhesion affecting yield and throughput

Engineering Contradiction:

Improvecapacitance effectVSAvoidyield and throughput

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent replaces the problematic organic insulator film with a light-shielding pattern made from the existing second patterned conductive layer material. This approach eliminates the need for separate organic coating processes (photo-imaged and spin on glass), removing the associated reliability issues while maintaining the capacitance reduction function.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The light-shielding pattern performs multiple functions: it serves as the electromagnetic shielding structure to reduce parasitic capacitance, acts as a light-shielding element for display quality, and utilizes the existing second patterned conductive layer material already present in the pixel structure, eliminating the need for additional organic insulator film deposition.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7755735B2Pixel structure of liquid crystal display panel and method having first and second patterned conductive layers having respectively first and second data line sections and with second patterned conductive layer additionally including source, drain, and a floating light-shielding pattern disposed over the first data line section

Publication Date: 2010.07.13 AU OPTRONICS CORP

AI summary

A pixel structure of a liquid crystal display panel includes a scan line, a data line, a thin film transistor (TFT), a pixel electrode, a light-shielding pattern, and a common line. The data line includes a first data line section and a second data line section composed respectively of the first material layer and second material layer and electrically connected to each other through a plurality of contact plugs. In addition, the pixel electrode is electrically connected to a drain of the TFT, and the light-shielding pattern, which is a floating metal, is disposed over the first data line section. The common line, the light-shielding pattern, and the second data line section are composed of the same material layer.