Optical Laminate Patterning for Stable Liquid Crystal Cell Gaps

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Solution Overview

Problem

Conventional transmittance variable optical laminates face issues with non-uniform cell gap maintenance due to ball spacer movement, leading to short circuits and inconsistent in-plane optical color, and require separate substrates for transparent conductive layers, complicating the manufacturing process.

Innovation Solution

Incorporation of ball spacers into pattern portions on polarizing plates with specific geometric constraints, eliminating the need for separate substrates and ensuring uniform cell gap and consistent optical color.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If ball spacers are used to maintain the cell gap of the liquid crystal layer, then the cell gap can be maintained, but the ball spacers move due to gravity causing non-uniform cell gap and short circuits

Engineering Contradiction:
Improvecell gap uniformityVSAvoidshort circuit prevention
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent divides the single ball spacer into multiple smaller ball spacers arranged in a specific pattern. This segmentation prevents any single spacer from moving significantly under gravity, as the multiple smaller spacers distribute the load and constrain each other's movement, thereby maintaining uniform cell gap while preventing short circuits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent pre-arranges multiple ball spacers in a specific pattern before assembling the liquid crystal cell. This preliminary positioning ensures that the spacers are evenly distributed and constrained from the start, preventing gravity-induced movement that would otherwise occur with single or randomly placed spacers.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If a separate substrate is used for forming the transparent conductive layer, then the conductive layer can be formed, but the manufacturing process becomes complicated

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidnumber of substrates
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the transparent conductive layer formation with the polarizing plate structure. Instead of using a separate substrate for the conductive layer, the conductive layer is formed directly on the polarizing plate, reducing the number of components and simplifying the manufacturing process while maintaining electrical functionality.

Inventive Principle:
Principle #5Merging (Combining)

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

Minimizes spacer movement, maintains uniform cell gap, prevents short circuits, and simplifies manufacturing by integrating conductive layers directly on polarizing plates, enhancing flexibility and optical performance.

Implementation Method 1

The transmittance variable optical laminate is driven to change transmittance by driving liquid crystals in response to application of a voltage

Methodology Applied
Scientific EffectLiquid crystal response to voltage: Electro-Optic Effects

Implementation Method 2

the ball spacers are incorporated into the pattern portions

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Data Source

PatentEP4586002A1Optical laminate, method for manufacturing the same, smart window including the same, and automobile and window for building using the same
Publication Date: 2025.07.16 DONGWOO FINE CHEM CO LTD
  • EP4586002A1 patent drawingFigure 1~2c
  • EP4586002A1 patent drawingFigure 2d~3
  • EP4586002A1 patent drawingFigure 4~5

AI summary

Disclosed is a transmittance variable optical laminate including: a first polarizing plate; a first transparent conductive layer formed on one surface of the first polarizing plate; a second polarizing plate opposite to the first polarizing plate; a second transparent conductive layer formed on one surface of the second polarizing plate and opposite to the first transparent conductive layer; and a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer and including ball spacers, wherein at least one of the first polarizing plate and the second polarizing plate includes a functional layer having a plurality of pattern portions satisfying Equation 1, and the ball spacers are incorporated into the pattern portions. Also disclosed are a method for manufacturing the optical laminate, a smart window including the optical laminate, and an automobile or a window for a building using the same.