Hemispherical Spacer Design for Uniform Liquid Crystal Orientation

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Solution Overview

Problem

Existing optical device substrates face challenges in maintaining uniform orientation treatment and cell gap due to spacer geometry, leading to non-uniform optical performance.

Innovation Solution

A substrate with a hemispherical spacer design, where the spacer features a curved hemispherical portion on top and a tapered portion at the bottom, allowing for uniform orientation treatment and maintaining cell gap uniformity, is developed. The spacer is formed using an ultraviolet curable resin through an imprinting method, with controlled dimensions and curvature to ensure optimal alignment film formation and device performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional spacer geometry is used, then spacer function is provided, but uniform orientation treatment and cell gap uniformity deteriorate

Engineering Contradiction:
Improvecell gap uniformityVSAvoidorientation treatment uniformity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The spacer is designed with a hemispherical top surface instead of a flat or sharp geometry. This curved surface allows the alignment film to conform smoothly without creating step discontinuities, enabling uniform orientation treatment across the substrate while maintaining precise cell gap control.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The spacer incorporates different geometric features in different regions: a hemispherical top portion for uniform alignment film contact and orientation treatment, and a tapered bottom portion for stable base layer attachment. This localized differentiation resolves the contradiction between operational ease and manufacturing precision.

Inventive Principle:
Principle #3Local quality

2Reliability

If spacer step influence is present, then spacer structure is simple, but optical performance deteriorates

Engineering Contradiction:
Improveoptical performanceVSAvoidspacer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hemispherical top surface of the spacer eliminates sharp edges and step discontinuities that would otherwise disrupt alignment film formation and cause optical defects. This curved geometry ensures uniform liquid crystal orientation and prevents light leakage, significantly improving optical performance while maintaining a relatively simple single-piece spacer structure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 substrate enables uniform orientation treatment and maintains excellent optical performance by minimizing the influence of spacer steps, resulting in improved light modulation and reduced light leakage, with enhanced transmittance, contrast ratios, and image visibility.

Implementation Method 1

The spacer is formed using an ultraviolet curable resin through an imprinting method

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3647862B1Process for preparing a substrate for an optical device
Publication Date: 2024.04.03 LG CHEM LTD
  • EP3647862B1 patent drawingFigure 1~3
  • EP3647862B1 patent drawingFigure 4~5
  • EP3647862B1 patent drawingFigure 6~7

AI summary

The present application relates to a substrate on which a specific type spacer is formed, a substrate comprising an alignment film formed on the spacer, and an optical device using such a substrate. In the present application, by controlling the shape of the spacer formed on the substrate, even when the alignment film is formed on the top and the orientation treatment is performed, the uniform orientation treatment can be performed without any influence by the step or the like of the spacer, whereby a substrate or the like capable of providing a device having excellent optical performance can be provided.