Liquid Crystal Display Trench Common Electrode Ion Collection
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Solution Overview
Problem
Liquid crystal displays face issues with reduced voltage holding ratio (VHR) and residual DC due to impurity ions floating in the liquid crystal layer, leading to luminance deterioration and afterimage effects.
Innovation Solution
A liquid crystal display design featuring a trench in the passivation film of the light-shielding region with a common electrode having a shorter vertical spacing to the pixel electrode, and a cell gap maintaining member with a conductive material covering the common electrode, effectively collecting impurity ions and improving the VHR and residual DC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trench is formed in the passivation film to create shorter vertical spacing between common electrode and pixel electrode, then impurity ion collection is improved and VHR increases, but device structure becomes more complex
Solution Approach 1:
The passivation film is segmented by forming a trench that divides it into different height regions. This segmentation creates a localized area with shorter vertical spacing between the common electrode and pixel electrode, enabling effective ion collection without requiring complete structural redesign of the entire display device.
Solution Approach 2:
The solution transitions from a two-dimensional planar structure to a three-dimensional structured design by forming a trench with depth. This vertical dimensionality change creates the shorter spacing region while maintaining overall device functionality, allowing ion collection enhancement without excessive horizontal expansion.
2Object-generated harmful factors
If a trench with common electrode is formed to collect impurity ions, then residual DC is reduced, but manufacturing process becomes more complex
Solution Approach 1:
The trench is formed in the passivation film during the manufacturing process before final assembly, and the common electrode is subsequently formed within this pre-prepared trench structure. This preliminary action of creating the trench enables effective ion collection and residual DC reduction while integrating the complex feature into the existing manufacturing flow.
3Reliability
If vertical spacing between common electrode and pixel electrode is reduced in light-shielding region, then ion collection efficiency is improved, but risk of electrical breakdown increases
Solution Approach 1:
The shorter vertical spacing is applied locally only in the light-shielding region where ion collection is most needed, rather than uniformly across the entire display. This localized approach maximizes ion collection efficiency in the critical area while maintaining adequate spacing in other regions to prevent electrical breakdown.
Solution Approach 2:
The passivation film acts as an intermediary structure that is selectively removed to form the trench. This intermediary approach allows precise control over where the shorter spacing occurs, enabling ion collection enhancement while maintaining electrical safety through controlled geometry and insulation.
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
The design enhances the voltage holding ratio and reduces residual DC, resulting in improved display quality with better luminance and no afterimage effects.
Implementation Method 1
A liquid crystal display design featuring a trench in the passivation film of the light-shielding region with a common electrode having a shorter vertical spacing to the pixel electrode, and a cell gap maintaining member with a conductive material covering the common electrode, effectively collecting impurity ions
Data Source
AI summary
A liquid crystal display includes a first display panel having a light-transmitting region and a light-shielding portion, a second display panel that faces the first display panel with liquid crystals interposed between the first and second display panels and that includes a TFT substrate, a pixel electrode on the TFT substrate, a passivation film on the TFT substrate and the pixel electrode, and a common electrode patterned on the passivation film, and a trench in the passivation film within the light-shielding region between the first and second display panels. The trench encloses the light-transmitting region, and the common electrode is on the trench.