Optical Element Manufacturing with Light-Absorbing Support

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Solution Overview

Problem

The existing methods for manufacturing optical elements with liquid crystal layers face issues of in-plane unevenness due to reflection of coherent light from the support surface, leading to irregular alignment patterns and compromised optical properties.

Innovation Solution

A method involving the use of a support with a light absorption band that overlaps the light absorption band of the alignment film, where the alignment film is exposed to polarized light with different polarization directions, and the support absorbs a significant portion of the incident light to minimize reflection and unevenness, resulting in an optically-anisotropic layer with reduced in-plane unevenness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If coherent light is used to expose the alignment film to form an alignment pattern, then the alignment pattern can be formed efficiently, but in-plane unevenness occurs in the liquid crystal layer due to light reflection from the support surface

Engineering Contradiction:

Improvealignment pattern formation efficiencyVSAvoidin-plane unevenness of liquid crystal layer

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent converts the harmful reflection of coherent light from the support surface into a beneficial effect by using the reflected light to form a polarization interference pattern that creates the desired alignment pattern in the liquid crystal layer. The support surface acts as a mirror to generate the interference pattern that aligns the liquid crystal molecules uniformly, eliminating the in-plane unevenness caused by direct coherent light exposure.

Inventive Principle:

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

2Ease of manufacture

If the alignment film is exposed to coherent light with orthogonal circular polarizations, then a polarization interference pattern is formed for liquid crystal alignment, but unevenness occurs in the pattern and liquid crystal layer

Engineering Contradiction:

Improveliquid crystal alignment capabilityVSAvoidpattern uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

Instead of directly exposing the alignment film to coherent light from above, the patent inverts the approach by using the support surface as a reflective mirror. The coherent light passes through the alignment film and liquid crystal layer, reflects off the support surface, and creates the polarization interference pattern on its way back. This inversion eliminates direct reflection interference and achieves uniform pattern formation.

Inventive Principle:

Principle #13The other way round (Inversion)

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 approach effectively reduces in-plane unevenness in the liquid crystal alignment, enabling the production of optical elements with improved optical properties and desired diffraction capabilities.

Implementation Method 1

the support has a light absorption band that overlaps a light absorption band where a photochemical reaction occurs in the alignment film by irradiating the alignment film with the polarized light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a photochemical reaction occurs in the alignment film by irradiating the alignment film with the polarized light

Methodology Applied

Scientific EffectPhotochemical reaction: Photo-oxidation

Implementation Method 3

an alignment film that aligns the liquid crystal compound, and a support

Methodology Applied

Scientific EffectPhoto-alignment: Photoplastic Effect

Data Source

PatentUS11333933B2Method of manufacturing optical element and optical element

Publication Date: 2022.05.17 FUJIFILM CORP

AI summary

Provided are a method of manufacturing an optical element in which an optically-anisotropic layer having a small amount of in-plane unevenness can be prepared, and an optical element. The method of manufacturing an optical element is a method of manufacturing an optical element, the optical element including an optically-anisotropic layer that is formed using a liquid crystal composition including a liquid crystal compound, an alignment film that aligns the liquid crystal compound, and a support, the method including: an alignment film forming step of forming the alignment film on one surface of the support; and an optically-anisotropic layer forming step of forming the optically-anisotropic layer on the alignment film, in which the alignment film includes a photo-alignable material, the alignment film forming step includes an exposure step of exposing different in-plane positions of the alignment film to light components having different polarization directions, and the support has a light absorption band that overlaps a light absorption band where a photochemical reaction occurs in the alignment film by irradiating the alignment film with the polarized light in the exposure step.