Irregular Spacer Arrangement in Light-Modulating Cell

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Solution Overview

Problem

In light-modulating cells with liquid crystal cells, regular spacer arrangements lead to interference of diffracted light, causing blurred observation light and reduced visibility, particularly in guest-host liquid crystal systems, where existing solutions fail to effectively mitigate this issue.

Innovation Solution

The spacers in the light-modulating cell are arranged irregularly with varying distances between them, and are designed with a tapered shape and photocurable resin materials, allowing for accurate alignment and reduced interference of diffracted light, while maintaining effective position fixing properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If spacers are regularly arranged with constant distance, then manufacturing precision is improved, but visibility of observation light deteriorates due to interference of diffracted light

Engineering Contradiction:
Improvespacer arrangement regularityVSAvoidvisibility of observation light
Core Design Contradiction:
Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The patent applies asymmetry by intentionally introducing irregularity into the spacer arrangement. Instead of maintaining constant distance between spacers, the invention varies the spacing between adjacent spacers, breaking the periodic symmetry that causes constructive interference of diffracted light. This asymmetric arrangement eliminates the regular interference pattern while preserving adequate manufacturing precision through controlled variation.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent changes the parameter of spacer distance from constant to variable. By making the distance between adjacent spacers non-uniform, the invention alters the diffraction conditions to prevent periodic interference. The parameter change is implemented while maintaining overall structural integrity and functional performance of the light-modulating cell.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If spacers are irregularly arranged, then visibility of observation light is improved, but manufacturing precision deteriorates

Engineering Contradiction:
Improvevisibility of observation lightVSAvoidspacer arrangement regularity
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent implements controlled parameter changes in spacer positioning. Rather than complete randomness, the invention introduces specific variations in spacer distance that are sufficient to break interference patterns but manageable within manufacturing tolerances. This approach balances optical performance improvement with manufacturing feasibility.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies partial irregularity to the spacer arrangement - not all spacers need perfectly uniform spacing, but sufficient variation is introduced to eliminate interference. The invention uses minimal necessary deviation from regularity to achieve the optical benefit, avoiding excessive complexity in manufacturing.

Inventive Principle:
Principle #16Partial or excessive action

3Stability of the object's composition

If spacers are provided to hold liquid crystal layer thickness, then liquid crystal orientation is maintained, but interference of diffracted light occurs causing blurred observation

Engineering Contradiction:
Improveliquid crystal layer thicknessVSAvoidinterference of diffracted light
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent uses asymmetric spacer arrangement to eliminate the harmful interference effect while preserving the spacers' primary function of maintaining liquid crystal layer thickness. The irregular spacing disrupts the diffraction interference pattern without compromising the structural support and thickness control provided by the spacers.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent converts the harmful diffraction interference caused by regular spacers into a beneficial situation by introducing irregular spacing. The same spacers that cause interference when regularly arranged become harmless or even beneficial when irregularly arranged, as they continue to fulfill their thickness-maintenance function while eliminating the optical defect.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 arrangement significantly reduces the periodic interference of diffracted light, enhancing the visibility of observation light by eliminating the blurring effect, even in curved structures and guest-host liquid crystal applications.

Implementation Method 1

interference of diffracted light generated by the plurality of spacers

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

interference of diffracted light generated by the plurality of spacers

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP3798721B1Light-modulating cell
Publication Date: 2024.11.20 DAI NIPPON PRINTING CO LTD
  • EP3798721B1 patent drawingFigure 1~2
  • EP3798721B1 patent drawingFigure 3
  • EP3798721B1 patent drawingFigure 4~5

AI summary

1. A light-modulating cell includes: a pair of film substrates; a pair of electrodes arranged between the pair of film substrates; a pair of alignment films arranged between the pair of electrodes; a plurality of spacers supporting at least any one of the pair of alignment films and being in contact with at least any one of the pair of alignment films; and a liquid crystal layer arranged between the plurality of spacers between the pair of alignment films. The liquid crystal layer contains at least a dichroic pigmen. At least some of the plurality of spacers are randomly arranged so as to reduce the interference effects of light diffracted from the plurality of spacers. In the light modulating cell no polarizing plate is provided, and the light modulating cell is configured such that the alignment of the dichroic pigment is twisted by 180 degrees or more with respect to a direction parallel to the film substrates in a state where no electric field is applied.