Phase Shift Pattern for Light Leakage in Display Devices

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Solution Overview

Problem

In the manufacturing of TFT-LCD devices, position deviations during cell-assembling lead to inconsistent light transmission rates, particularly in high PPI products, resulting in reduced customer experience due to fluctuations up to 30% in light transmission uniformity.

Innovation Solution

The introduction of a phase shift pattern on the array substrate, made of materials like MoSiON, which allows light to undergo phase shift, creating opaque areas and preventing light leakage and color cross-talk, thereby maintaining uniform light transmission even with assembly deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a black matrix pattern is used to block light from signal lines, then light leakage is prevented, but light transmission rate decreases and uniformity deteriorates due to position deviations in cell-assembling

Engineering Contradiction:
Improvelight leakageVSAvoidlight transmission uniformity
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent changes the optical parameter of the signal lines by forming a phase shift pattern on them. This pattern modifies the phase of transmitted light to create an interference effect that produces opaque portions, transforming the signal lines from light-transmissive to light-blocking without using traditional black matrix materials. This resolves the contradiction by preventing light leakage while maintaining light transmission uniformity despite assembly position deviations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The phase shift pattern acts as an intermediary structure on the signal lines. It doesn't directly block light like a black matrix but instead modifies light phase to create interference patterns that result in opaque portions. This intermediary approach prevents light leakage between sub-pixels while avoiding the uniformity issues caused by traditional black matrix methods sensitive to assembly positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If the aperture ratio of sub-pixels is increased to improve display brightness, then light transmission increases, but position deviations cause greater fluctuations in light transmission rate

Engineering Contradiction:
Improvedisplay brightnessVSAvoidlight transmission uniformity
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies phase shift patterns to signal lines to create opaque portions that define precise boundaries for light transmission. This allows sub-pixels to have larger aperture ratios for improved brightness while the phase shift-induced opaque portions maintain consistent light transmission rates by creating stable interference patterns that are less sensitive to assembly position variations.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If traditional black matrix patterns are used to separate sub-pixels, then color cross-talk is prevented, but manufacturing complexity increases due to additional alignment requirements

Engineering Contradiction:
Improvecolor cross-talkVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the function of signal lines with the function of light-blocking structures by forming phase shift patterns directly on the signal lines. This eliminates the need for separate black matrix patterns and their associated alignment requirements, preventing color cross-talk while reducing manufacturing complexity. The signal lines simultaneously serve as both electrical conductors and optical boundary definers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The signal lines acquire multi-functionality by incorporating phase shift patterns. They continue to serve their primary function of electrical signal transmission while simultaneously performing the function of creating opaque portions to prevent color cross-talk and define sub-pixel boundaries. This universal approach eliminates the need for separate dedicated structures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution ensures consistent light transmission rates across products, maintaining high uniformity and reducing luminance differences, especially in high PPI devices, by using a phase shift pattern to counteract light energy and prevent light leakage, thus enhancing customer experience.

Implementation Method 1

a phase shift pattern 103 disposed on the base substrate 101 to separate the sub-pixels 102; the phase shift pattern 103 is disposed to allow light passing through the phase shift pattern 103 to undergo phase shift

Methodology Applied
Scientific EffectPhase shift: Phase Change

Implementation Method 2

light passing through the phase shift pattern 103 and light not passing through the phase shift pattern 103 interfere with each other, and therefore substantially opaque areas are formed

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP3290999B1A display device and a manufacturing method thereof
Publication Date: 2022.09.07 BOE TECHNOLOGY GROUP CO LTD
  • EP3290999B1 patent drawingFigure 1~2
  • EP3290999B1 patent drawingFigure 3~5a
  • EP3290999B1 patent drawingFigure 5b~5d

AI summary

An array substrate and a manufacturing method thereof and a display are disclosed. The array substrate (10) includes a base substrate (101), a plurality of sub-pixels (102) disposed on the base substrate (101), and a phase shift pattern (103) disposed on the base substrate (101) to separate the sub-pixels (102); the phase shift pattern (103) is disposed to allow light passing through the phase shift pattern (103) to undergo phase shift, and positions corresponding to the phase shift pattern are substantially opaque to light. Lateral light leakage is reduced by the phase shift pattern, and transmission rate of products become uniform, and therefore stability of products are increased.