Switchable Refractive-Diffractive Lens for Presbyopia
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Solution Overview
Problem
Current lenses for presbyopia correction, such as multifocal refractive or diffractive lenses, often fail to provide seamless switching between far and near foci, leading to vision deficiencies due to their fixed power and complex, expensive operational mechanisms, particularly in ophthalmic applications where electrical control is challenging.
Innovation Solution
A switchable cell comprising an optical substrate with a diffraction surface, an elastic film, and a transparent or active chamber filled with matching or non-matching optical fluid, which changes the optical surface shape between refractive and diffractive states to adjust focal lengths, allowing for mechanical switching between far and near foci without external actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multifocal refractive or diffractive lenses are used for presbyopia correction, then multiple foci are provided, but seamless switching between far and near foci is not achieved
Solution Approach 1:
The patent applies the dynamics principle by creating a lens that can dynamically change its optical state between refractive and diffractive modes. The switchable cell mechanism allows the lens to transition between different focal states (far and near) by changing the refractive index of the optical fluid through temperature control, enabling seamless switching between multiple foci while maintaining adaptability.
Solution Approach 2:
The patent utilizes parameter changes by modifying the refractive index of the optical fluid in the switchable cell through temperature variation. This parameter change enables the lens to switch between refractive and diffractive states, providing seamless transition between far and near foci while maintaining the multiple focus capability.
2Extent of automation
If electrical control mechanisms are used for switching between foci, then automated focus switching is achieved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex electrical control mechanisms with a simpler thermal control system. By using temperature-dependent refractive index changes in the optical fluid, the system achieves automated focus switching through thermal actuation rather than electrical fields, reducing device complexity and cost while maintaining automation.
Solution Approach 2:
The patent changes the control parameter from electrical field to temperature. This parameter substitution simplifies the control mechanism by using thermal effects instead of electrical fields, reducing the complexity of the automated switching system while maintaining its functionality.
3Ease of manufacture
If fixed power lenses are used, then manufacturing simplicity is maintained, but vision deficiency occurs due to limited viewing range
Solution Approach 1:
The patent transforms a static fixed-power lens into a dynamic multifocal lens by incorporating a switchable cell that can change between refractive and diffractive states. This dynamic capability allows the lens to provide multiple viewing ranges (far and near) while maintaining relative manufacturing simplicity through the modular switchable cell design.
Solution Approach 2:
The patent makes a single lens structure universal by enabling it to perform multiple functions - providing both far vision and near vision capabilities. The switchable cell allows the same lens to serve multiple viewing distance requirements, increasing adaptability without requiring multiple separate lenses.
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 enables a stable, cost-effective, and efficient switching mechanism between refractive and diffractive states, providing improved vision by adjusting focal lengths based on the optical surface shape, addressing the limitations of existing technologies in ophthalmic applications.
Implementation Method 1
changes the refractive surface of the lens into diffraction surface
Implementation Method 2
creating an image at a position produced by the lens in diffractive state that is different from the image position produced by the lens in refractive state
Implementation Method 3
an elastic film, and a transparent or active chamber filled with matching or non-matching optical fluid
Data Source
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AI summary
The invention refers to a pair of spectacles having a frame, the pair of spectacles comprising at least one switchable lens attached to the pair of spectacles, the at least one switchable lens configured to switch its foci from a far focal length to a near focal length, where the near focal length is smaller than the far focal length; an infrared emitter disposed at one side periphery of the at least one switchable lens and/or frame, the infrared emitter configured to emit an infrared radiation; an infrared sensor disposed at an opposite side periphery of the at least one switchable lens and/or frame, the infrared sensor configured to detect the infrared radiation from the infrared emitter; wherein the at least one switchable lens is configured to switch to its far focal length when the infrared sensor detects an intensity of infrared radiation that has been emitted and reflected off a front surface of a wearer's eye ball when the wearer is looking forward; and wherein the at least one switchable lens is configured to switch to its near focal length when the infrared sensor detects a different intensity of infrared radiation when the infrared radiation is changed in reflecting off the front surface of the wearer's eye ball by an upper eyelid of the wearer when the wearer is looking downward .