Switchable Ophthalmic Lens Using Birefringent Light Rotators
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Solution Overview
Problem
Current ophthalmic lenses for correcting presbyopia and other vision defects often suffer from limitations such as size constraints, limited optical power variation, chromatic aberration, and high-order diffraction modes, leading to artifacts like distortion and spatial restrictions, and require multiple lens changes for optimal correction.
Innovation Solution
An ophthalmic lens arrangement featuring a polarizer, switchable light rotators, and birefringent lens members with ordinary and extraordinary refractive indices, allowing for rotation of incident light by 0° or 90°, and a complex intermediary surface for adjustable optical power, enabling a full field of view with switchable dioptric values for near and far vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bifocal or multifocal contact lenses are used to correct presbyopia, then near and far vision are corrected with the same lenses, but artifacts such as distortion and spatial restrictions occur
Solution Approach 1:
The patent employs switchable liquid crystal rotators that can dynamically change the optical path between ordinary and extraordinary rays, allowing the lens to switch between different optical power states (far vision and near vision) without the fixed zones of traditional multifocal lenses, thereby eliminating distortion and spatial restrictions while maintaining versatility
Solution Approach 2:
The patent utilizes birefringent lens members with different refractive indices (no and ne) and switchable light rotators that can rotate incident light by 0° or 90°, changing the effective refractive index experienced by light. This parameter change allows a single lens to provide multiple optical powers for different viewing distances without the artifacts associated with traditional multifocal designs
2Adaptability or versatility
If progressive ophthalmic lenses are used, then gradual power progression from far to near vision is provided, but the design and manufacture become complicated
Solution Approach 1:
The patent replaces the static progressive corridor design with dynamic switchable lens cells containing liquid crystal rotators. This allows power progression to be achieved through active switching between discrete optical states rather than complex progressive surface shaping, significantly simplifying design and manufacture while maintaining the ability to provide gradual power transitions
Solution Approach 2:
The patent divides the lens into multiple independent lens cells, each capable of being switched independently. This segmentation allows the complex power progression function to be achieved through simple switching of individual cells rather than requiring complex progressive surface geometry, reducing manufacturing complexity
3Measurement precision
If traditional fitting techniques with multiple lens trials are used, then the best optical performance is selected, but the process requires putting off and taking off multiple spectacles
Solution Approach 1:
The patent incorporates multiple lens cells with different optical characteristics into a single ophthalmic lens arrangement. The switchable rotators allow all lens options to be present simultaneously, enabling the wearer to experience different optical functions without removing the spectacles, thus saving time while maintaining the ability to select the best optical performance
Solution Approach 2:
The patent pre-configures multiple lens cells with different optical powers and characteristics within a single lens assembly. This preliminary preparation allows the wearer to try different optical functions by simply switching rotators rather than physically changing lenses, dramatically reducing the time required for the fitting process while ensuring optimal optical performance selection
4Reliability
If prior art ophthalmic lens arrangements are used, then optical correction is provided, but limitations in size, optical power variation amplitude, and chromatic aberration occur
Solution Approach 1:
The patent uses composite lens structures combining birefringent materials with different refractive indices (no and ne) and switchable liquid crystal rotators. This composite approach enables a wider range of optical power variation and reduced chromatic aberration compared to single-material lenses, while maintaining reliable optical correction across different viewing conditions
Solution Approach 2:
The patent introduces sub-lens members as intermediary elements between the birefringent lens members and the eye. These sub-lens members help correct chromatic aberration and extend the effective optical power range, allowing the system to overcome the limitations of prior art while maintaining reliable correction
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 solution provides a flexible and efficient correction for presbyopia and other vision defects by allowing adjustable optical power and reducing artifacts like distortion, enabling a full field of view for both near and far vision without the need for multiple lens changes.
Implementation Method 1
a polariser for polarising light in a polarisation axis
Implementation Method 2
a lens member having birefringence properties such that incident light encounters a first refractive index no on an ordinary axis or a second refractive index ne on an extraordinary axis according to the rotation of the incident light
Implementation Method 3
incident light encounters a first refractive index no on an ordinary axis or a second refractive index ne on an extraordinary axis
Implementation Method 4
at least one lens cell including a switchable light rotator; the or each rotator is operable to rotate incident light by 0° or by 90°
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
The invention relates to an ophthalmic lens arrangement (10) comprising a polariser (11) for polarising light in a polarisation axis; at least one lens cell (13) including a switchable light rotator; a lens member (15) having birefringence properties such that incident light encounters a first refractive index n on an ordinary axis or a second refractive index ne on an extraordinary axis according to the rotation of the incident light; and a sub lens member (17) having a refractive index n; characterized in that: the or each rotator is operable to rotate incident light by 0° or by 90°, and the polariser is arranged such that the polarisation axis coincides with either the ordinary axis or the extraordinary axis of the or each lens member. The invention further relates to an apparatus for and a method for demonstrating a plurality of optical functions.