Electro-active lenses with thin glass substrates
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Solution Overview
Problem
Current electronic focusing eyeglasses are costly due to the need for expensive materials like 1.67 optical grade plastic for the lenses, which limits material options and increases production costs, and face challenges with durability and scratch resistance.
Innovation Solution
A self-contained electro-active optical cell with a layer of electro-active material between glass substrates, allowing for changeable optical power with an electrical potential, which can be affixed to various lens blanks made from different materials, including less expensive plastics, and is designed to provide scratch resistance and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If expensive 1.67 optical grade plastic is used for the lens blank to achieve proper index of refraction matching, then the optical performance is improved, but the production cost increases significantly
Solution Approach 1:
The patent divides the lens into two independent parts: a lens blank and an electro-active cell. The lens blank can be made from inexpensive materials while the electro-active cell contains the expensive liquid crystal material. This segmentation allows the expensive optical material to be confined to only where it's needed for the electro-active function, rather than requiring the entire lens blank to be made from expensive 1.67 optical grade plastic.
Solution Approach 2:
The patent extracts the electro-active functionality into a separate self-contained cell that can be attached to various lens blanks. This extraction allows the lens blank material selection to be independent from the electro-active material requirements, enabling use of cheaper lens blank materials while maintaining the necessary optical properties in the electro-active region.
2Weight of moving object
If plastic lens material is used to reduce weight, then the weight is reduced, but the scratch resistance deteriorates
Solution Approach 1:
The patent creates a composite structure combining a plastic lens blank with a glass-based electro-active cell. The plastic blank provides light weight while the glass substrates and sealant in the electro-active cell provide scratch resistance and durability. This composite approach allows each material to contribute its advantageous properties to the overall lens system.
Solution Approach 2:
The patent applies different material properties to different regions of the lens. The lens blank can be made from lightweight plastic, while the electro-active cell region uses scratch-resistant glass materials. This local differentiation of material properties allows the lens to be lightweight overall while having scratch-resistant surfaces where needed.
3Reliability
If glass substrates are used in the electro-active cell, then scratch resistance and thermal stability are improved, but the device complexity increases
Solution Approach 1:
The patent designs the electro-active cell with glass substrates and sealant that serve multiple functions: providing scratch resistance, thermal stability, mechanical strength, and hermetic sealing. The glass materials fulfill both structural and protective roles, reducing the need for additional separate components and simplifying the overall cell design despite the use of glass materials.
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 reduces production costs, allows for material independence, and enhances durability and scratch resistance, making electronic focusing eyeglasses more affordable and versatile.
Implementation Method 1
a layer of electro-active material between glass substrates, allowing for changeable optical power with an electrical potential
Data Source
AI summary
An electro-active optical cell is described including a layer of electro-active material, a front glass substrate member, and a back glass substrate member. The optical cell is capable of independently providing changeable optical power with the application of an electrical potential. The cell is also configured to be affixed to an external surface of a plastic substrate and to provide the changeable optical power, with at least one of the front substrate or the back substrate of the optical cell being an outermost optical layer. The layer of electro-active material may have a thickness less than 10 μm, and the glass substrate members may each have a thickness approximately between 20 μm and 500 μm.