Thin Polarizing Lens for Rimless Sunglasses
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Solution Overview
Problem
Current methods for producing lightweight rimless sunglasses with polarizing lenses face challenges in achieving sufficient clamping force and mechanical strength while maintaining a reduced weight, as thinner lenses compromise strength and thicker lenses increase weight, leading to issues with lens durability and frame stability.
Innovation Solution
A polarizing lens with an injection-molded polyamide-based resin layer, adjusted for specific flexural modulus and center thickness, is integrated into rimless sunglasses to enhance clamping force and mechanical strength, allowing for a lightweight design without compromising durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of the polarizing lens is reduced to decrease weight, then the weight of the sunglasses is reduced, but the mechanical strength and clamping force are insufficient
Solution Approach 1:
The patent uses a composite structure consisting of a polarizing film layer and a resin layer (polycarbonate or polyester) to create a laminated polarizing lens. This composite material approach allows the lens to achieve sufficient mechanical strength and clamping force while maintaining reduced thickness and weight, resolving the contradiction between lightweight design and structural strength.
2Strength
If the thickness of the polarizing lens is increased to increase mechanical strength, then the clamping force is sufficient, but the weight of the sunglasses increases
Solution Approach 1:
The patent optimizes the thickness parameters of the polarizing film layer (5-50 μm) and resin layer (0.5-1.5 mm) to achieve the desired clamping force while minimizing weight. By precisely controlling these dimensional parameters, the lens provides sufficient mechanical strength without excessive thickness, thus resolving the weight-strength trade-off.
3Weight of moving object
If the thickness of the polarizing lens is reduced to decrease weight, then the weight is reduced, but the lens is prone to breakage from external forces
Solution Approach 1:
The laminated structure combining polarizing film and resin layer provides both weight reduction and enhanced durability. The resin layer acts as a protective barrier that absorbs external forces and prevents breakage, while the overall thin design maintains lightweight characteristics, thus resolving the contradiction between weight reduction and durability.
Solution Approach 2:
The resin layer in the composite structure serves as a pre-established protective cushion that absorbs and dissipates external forces before they can cause breakage to the polarizing film. This beforehand cushioning mechanism ensures the lens maintains reliability and resistance to breakage even at reduced thickness.
4Ease of manufacture
If polarizing film is punched and bent to form lens shape, then the lens is formed, but variation in optical properties occurs making stable production difficult
Solution Approach 1:
The patent performs punching and bending operations on the polarizing film before lamination with the resin layer. By conducting these forming operations beforehand on the flat film, the subsequent lamination process preserves the formed shape and optical properties, reducing variation and enabling stable production of polarizing lenses with consistent optical characteristics.
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
The solution provides rimless sunglasses with a total weight of 10g or less, maintaining sufficient clamping force and mechanical strength, preventing lens and frame damage from external forces, and ensuring optical quality and chemical resistance.
Implementation Method 1
A polarizing lens is a lens in which a lens and a polarizing film are integrated, and has an effect of reducing bright reflected light and glare
Implementation Method 2
a resin injection-molded layer formed by resin injection molding on a polarizing sheet
Data Source
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AI summary
An object of the present invention is to provide a thin and lightweight polarizing lens for use in lightweight sunglasses (in particular, rimless sunglasses) while maintaining the clamping force and mechanical strength of a temple part, and a manufacturing method therefor. The values of: the center thickness v of a polarizing lens A including an injection-molded layer 3 laminated on at least one surface of a polarizing sheet B, the injection-molded layer having a polyamide-based resin; and the flexural modulus of the injection-molded layer 3 are adjusted, thus the predetermined clamping force and mechanical strength of a temple part are obtained even in the case of sunglasses with the thin and lightweight polarizing lens.