Flexible Liquid Crystal Contact Lens With Gap-Stabilizing Diffractive Optics
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Solution Overview
Problem
Existing flexible contact lenses with diffractive optical elements face challenges in maintaining cell gap thickness, leading to optical haze and reduced optical performance when deformed on the eye.
Innovation Solution
Utilizing a diffractive optical element as a spacer to maintain cell gap thickness, with a design where the maximum height of the optical element at the outer portion is greater than at the inner portion, and controlling refractive index differences between the liquid crystal and optical element states to minimize diffraction or maximize optical matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the contact lens is deformed on the eye, then the lens conforms to the eye shape, but the cell gap thickness varies leading to optical haze
Solution Approach 1:
The diffractive optical element is designed with non-uniform height characteristics, where the maximum height at the outer portion is greater than at the inner portion. This local variation in geometry compensates for the deformation that occurs when the lens is placed on the eye, maintaining relatively uniform cell gap thickness across the lens and preventing optical haze while allowing the lens to conform to the eye's curvature.
2Reliability
If the cell gap thickness is maintained uniformly, then optical performance is improved, but the lens cannot conform to the curved eye surface
Solution Approach 1:
The diffractive optical element employs asymmetric height distribution across its structure, with the outer portion having greater maximum height than the inner portion. This asymmetric design allows the element to maintain different cell gap thicknesses at different locations, enabling the lens to conform to the curved eye surface while preserving optical performance through controlled variation rather than uniformity.
3Object-generated harmful factors
If the refractive index difference between liquid crystal and optical element is large, then diffraction is maximized, but optical matching is reduced
Solution Approach 1:
The patent utilizes the electrically-switchable refractive index property of liquid crystal to dynamically control the refractive index difference between the liquid crystal and the diffractive optical element. By applying voltage, the refractive index of the liquid crystal changes, allowing the system to switch between states of high diffraction (when refractive index difference is large) and low diffraction/optical matching (when refractive index difference is small), thereby enabling controllable optical performance.
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
Maintains optical clarity and performance by limiting cell gap thickness variation, ensuring consistent optical path and reducing diffraction, even when the lens is deformed on the eye.
Implementation Method 1
The lenses may be provided with liquid crystal, which is electrically-switchable between two states. In a first state, the refractive index of the liquid crystal does not match the refractive index of the diffractive optical element and the diffractive optical element interacts with, and diffracts, the light. In a second state, the refractive index of the liquid crystal matches that of the diffractive optical element and there is no or very little diffraction of incident light.
Implementation Method 2
the diffractive optical element interacts with, and diffracts, the light
Data Source
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AI summary
An electrically-switchable flexible contact lens for conforming to an eye of a user is provided. The lens comprises a liquid crystal cell for changing a focal power of the contact lens, and the liquid crystal cell has a cell gap thickness between a first inner surface and a second inner surface, the liquid crystal cell comprising a diffractive optical element for correcting the vision of a user, wherein the diffractive optical element is arranged to maintain the cell gap thickness by providing support at one or more locations within the cell.