Optical Laminate Wavefront Control via Phase Adjustment Layer

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Solution Overview

Problem

Existing wavelength selective reflective elements, such as those using cholesteric liquid crystals, face challenges in arbitrarily designing the wavefront of reflected light, requiring precise control of liquid crystal alignment directions, which is difficult to achieve in practical applications.

Innovation Solution

An optical laminate comprising a wavelength selective reflective element with an absolute phase adjustment layer that has optical isotropy and an in-plane distribution of refractive index or film thickness, allowing for control of the wavefront of reflected light by altering the optical path length, thereby simplifying the design and practical application of wavefront control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a cholesteric liquid crystal layer is used as a wavelength selective reflective element, then selective reflection of specific circularly polarized light is achieved, but precise control of liquid crystal alignment direction is required which is difficult to achieve in practical applications

Engineering Contradiction:

Improveliquid crystal alignment direction controlVSAvoidpractical application difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent introduces an absolute phase adjustment layer as an intermediary component between the incident light and the wavelength selective reflective element. This layer has an in-plane distribution of optical path length that controls the wavefront of reflected light, thereby mediating the alignment control requirement and enabling wavefront design without precise liquid crystal alignment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If pattern alignment in steps of forming a cholesteric liquid crystal layer is used to control the phase of helical structure, then wavefront control is achieved, but the method is difficult to apply in practical use due to fine control requirements

Engineering Contradiction:

Improvewavefront design capabilityVSAvoidpractical applicability

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent separates the wavefront control function from the wavelength selective reflection function by introducing a distinct absolute phase adjustment layer. This segmentation allows the wavelength selective reflective element to focus on its primary function while the separate layer handles wavefront control, making the system more practical for manufacturing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The absolute phase adjustment layer has an in-plane distribution of optical path length, meaning different regions of the layer have different optical properties. This local variation in optical path length enables arbitrary wavefront design while maintaining ease of manufacture, as each region can be optimized independently.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If the wavefront of reflected light is controlled by spatially controlling the phase of the helical structure, then arbitrary wavefront design is achieved, but fine control of liquid crystal alignment direction is required

Engineering Contradiction:

Improvearbitrary wavefront designVSAvoidalignment direction control

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The absolute phase adjustment layer serves as a mediator that translates the desired arbitrary wavefront design into optical path length variations without requiring precise control of the liquid crystal alignment. This intermediary layer handles the complex wavefront control while the liquid crystal layer maintains its simpler function.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 optical laminate enables the wavefront of reflected light to be arbitrarily designed, enhancing reflection characteristics and simplifying the formation process by eliminating the need for precise alignment of the reflection layer, making it more suitable for practical use.

Implementation Method 1

A cholesteric liquid crystal which is a type of wavelength selective reflective element has a property of selectively reflecting specific circularly polarized light of a specific wavelength

Methodology Applied

Scientific EffectCholesteric liquid crystal selective reflection: Cholesteric Liquid Crystal

Implementation Method 2

a reflection layer selectively reflecting light in a specific reflection wavelength region

Methodology Applied

Scientific EffectSelective reflection: Reflection

Implementation Method 3

the absolute phase adjustment layer has an in-plane distribution of at least one of a refractive index or a film thickness, and thus has an in-plane distribution of an optical path length in a film thickness direction

Methodology Applied

Scientific EffectOptical path length distribution: Refraction

Data Source

PatentUS10613262B2Optical laminate

Publication Date: 2020.04.07 FUJIFILM CORP

AI summary

An optical laminate includes a wavelength selective reflective element which is provided with a reflection layer selectively reflecting light in a specific reflection wavelength region, and an absolute phase adjustment layer which is provided on at least one surface side of the wavelength selective reflective element and has optical isotropy, and the absolute phase adjustment layer has an in-plane distribution of at least one of a refractive index or a film thickness, and thus has an in-plane distribution of an optical path length in a film thickness direction.