Orthogonal Liquid Crystal Cell Layers for Birefringence Compensation
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Solution Overview
Problem
Tunable Liquid Crystal (TLCL) lenses used in intraocular implants suffer from birefringence-induced image offset, leading to double vision and reduced image quality due to the spatial variation of refractive index, which is challenging to compensate for in existing designs.
Innovation Solution
The proposed solution involves a pair of liquid crystal (LC) cell layers with orthogonal director orientations to modulate light polarizations differently, causing transversally non-uniform and uniform phase delays to compensate for birefringence-dependent offsets, ensuring both polarizations are focused in partial registration on an image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single layer of liquid crystal is used to control refractive index gradient, then the lens can focus a single polarization, but it cannot focus unpolarized or natural light
Solution Approach 1:
The patent combines two liquid crystal layers with orthogonal director orientations to create a single optical device that can focus unpolarized light. The first layer focuses one polarization component while the second layer focuses the orthogonal polarization component, merging their functions to achieve universal light focusing capability.
Solution Approach 2:
The patent segments the optical function by dividing the liquid crystal system into two separate layers, each handling a specific polarization component. This segmentation allows each layer to be optimized for its specific function while collectively solving the broader problem of unpolarized light focusing.
2Adaptability or versatility
If two layers of liquid crystal are used to provide natural light focusing, then unpolarized light can be focused, but birefringence-induced image offset occurs causing double vision
Solution Approach 1:
The patent introduces asymmetric positioning of the two liquid crystal layers relative to the optical axis. By offsetting the layers by a specific distance, the design compensates for the birefringence-induced image offset, causing the focal points of both polarization components to coincide and eliminate double vision.
Solution Approach 2:
The patent changes the spatial parameter (positioning distance) between the two liquid crystal layers to compensate for optical aberrations. By adjusting the offset distance, the system achieves proper alignment of focal points for both polarization components, improving image quality.
3Reliability
If liquid crystal layers are positioned to compensate for birefringence offset, then image quality improves, but the device complexity increases
Solution Approach 1:
The patent applies local quality by positioning only the liquid crystal layers asymmetrically while keeping other components symmetric. This localized asymmetry approach compensates for birefringence effects without requiring complete redesign of the entire optical system, thus limiting the increase in device complexity.
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 configuration effectively compensates for birefringence-induced offsets, improving image quality and reducing double vision by aligning the images from both LC layers, enhancing the focusing capabilities of TLCLs in intraocular implants.
Implementation Method 1
Tunable Liquid Crystal (TLCL) lenses used in intraocular implants suffer from birefringence-induced image offset
Implementation Method 2
each LC cell layer configured to cause transversally non-uniform and uniform phase delays to compensate for birefringence-dependent offsets
Implementation Method 3
An electrically variable gradient index (so called GRIN) lens can be formed by controlling the relative orientation of liquid crystal molecules to create a spatial variation of the index of refraction
Implementation Method 4
create a spatial variation of the index of refraction of the liquid crystal material within an aperture of the device
Data Source
AI summary
A liquid crystal optical device is provided including at least two LC cells. A first LC cell layer has a predominant director orientation imparting a transversally non-uniform phase delay to a first polarization of an unpolarized incident light field passing therethrough while incident light of a second polarization orthogonal to the first light polarization passes therethrough undergoing transversally uniform phase delay. The first LC cell is configured to project a center extraordinary ray onto an optical axis of the device at the image surface. A second LC cell layer has a predominant director oriented orthogonally to the other predominant director in a plane perpendicular to the optical axis. The second LC layer imparts a transversally non-uniform phase delay to the second polarization of the incident light passing therethrough, the second LC cell being configured to project a center ordinary ray onto the optical axis at the image surface.