Liquid Crystal Alignment on Diffractive Substrates

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Solution Overview

Problem

Existing techniques for aligning liquid crystalline materials with surface relief diffractive structures on non-planar substrates are inadequate, as they do not optimally align molecules with diffractive optical power regions, leading to suboptimal optical performance and vision compromises in electro-active lenses.

Innovation Solution

The use of a homogeneous alignment layer with specific alignments such as tangential, piecewise tangential, perpendicular, piecewise perpendicular, oblique, piecewise oblique, continuous intra-zone, or piecewise continuous intra-zone alignments on substrates with diffractive optical power regions, achieved through methods like rubbed or brushed materials and UV photosensitive alignment techniques, ensures optimal alignment of liquid crystalline materials with surface relief diffractive structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional alignment techniques are used on non-planar substrates with diffractive structures, then the alignment process is simpler, but the optical performance deteriorates due to suboptimal molecular alignment with diffractive optical power regions

Engineering Contradiction:

Improvealignment precisionVSAvoidalignment layer complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The alignment layer is configured with spatially varying alignment directions that match the local geometry of diffractive structures. Different regions of the alignment layer have different alignment patterns (e.g., radial, tangential, or azimuthal) to correspond to the local orientation of surface relief features, ensuring optimal liquid crystal alignment at each location on the non-planar substrate

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The alignment layer is prepared in advance on the non-planar substrate before liquid crystal deposition, pre-establishing the desired alignment pattern that corresponds to the diffractive optical power regions. This preliminary configuration ensures that when liquid crystal is applied, it naturally aligns with the pre-patterned alignment layer, achieving optimal orientation without complex post-processing

Inventive Principle:

Principle #10Preliminary action

2Reliability

If homogeneous alignment layer is used to achieve optimal alignment with diffractive structures, then diffraction efficiency improves, but the alignment process becomes more complex

Engineering Contradiction:

Improveoptical performanceVSAvoidalignment process ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces traditional mechanical rubbing alignment methods with photo-alignment techniques using UV irradiation. A photosensitive alignment layer is coated on the substrate and then irradiated with polarized UV light to create the desired alignment pattern, eliminating the need for mechanical contact and complex rubbing procedures while achieving homogeneous alignment

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The alignment characteristics are controlled by changing parameters of the alignment layer such as its chemical composition, thickness, and UV irradiation conditions. By adjusting these parameters, the alignment layer can be optimized to provide the required homogeneous alignment pattern that matches the diffractive structures, simplifying the overall manufacturing process

Inventive Principle:

Principle #35Parameter changes

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 enhances the optical performance of electro-active elements by achieving improved diffraction efficiency and reduced unwanted astigmatism, providing clearer vision with reduced vision compromises, especially in presbyopic individuals.

Implementation Method 1

an alignment layer disposed on a surface of the substrate having a homogeneous alignment that is one of a tangential alignment, a piecewise tangential alignment, a perpendicular alignment, a piecewise perpendicular alignment, an oblique alignment, a piecewise oblique alignment, a continuous intra-zone alignment, a piecewise continuous intra-zone alignment, or a combination thereof

Methodology Applied

Scientific EffectHomogeneous alignment:

Data Source

PatentUS8319937B2Alignment of liquid crystalline materials to surface relief diffractive structures

Publication Date: 2012.11.27 CARL ZEISS VISION INTERNATIONAL GMBH

AI summary

An alignment layer may align molecules of a liquid crystalline material to a surface of a substrate having a diffractive optical power region using a nonlinear alignment. The alignment layer may align the molecules of the liquid crystalline material in one of a tangential alignment, a piecewise tangential alignment, a perpendicular alignment, a piecewise perpendicular alignment, a continuous intra-zone alignment, or a piecewise continuous intra-zone alignment. The nonlinear alignment may result in optimal or near optimal alignment of the liquid crystalline material thereby resulting in improved optics and fewer vision compromises.