Aspherical Polarized Lens Thickness Reduction

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Solution Overview

Problem

Conventional polarized lenses with rotationally symmetric aspherical surfaces face challenges in reducing thickness due to the embedding of polarized films, which complicates the alignment and positioning of the polarized film relative to the aspherical object-side surface, leading to difficulties in achieving the same level of thinness as normal lenses.

Innovation Solution

The polarized lens design incorporates a first and second lens substrate with a rotationally symmetric aspherical object-side surface and an eyeball-side surface, respectively, with a polarized film positioned between them, ensuring concentricity in the in-plane distribution of the distance between the object-side surface and the polarized film, allowing for controlled thickness reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polarized film is embedded in an aspherical lens to achieve polarization function, then the lens can block light of predetermined polarization direction, but the thickness of the lens increases compared to normal lenses

Engineering Contradiction:
Improvepolarization functionVSAvoidlens thickness
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The polarized film is pre-formed with a convex shape matching the aspherical object-side surface before being positioned between the lens substrates. This preliminary shaping allows the film to conform to the aspherical geometry, enabling thin lens construction while maintaining the polarization function without requiring additional thickness accommodation

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If a rotationally symmetric aspherical surface is formed on the object-side surface to reduce aberration and thickness, then optical performance improves, but it becomes difficult to control the positioning of the polarized film

Engineering Contradiction:
Improveaspherical surface precisionVSAvoidpolarized film positioning
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent introduces asymmetry in the positioning of the polarized film relative to the aspherical surface by defining a specific distance W from the object-side surface. The film is positioned at a controlled distance rather than being embedded at the surface, which simplifies positioning while maintaining the aspherical geometry's optical benefits

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

A convex-shaped polarized film acts as an intermediary element between the aspherical object-side surface and the second lens substrate. The film's convex shape mediates the relationship between the aspherical surface and the polarization function, allowing precise control of the distance W while maintaining both geometric and optical requirements

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach enables the production of thinner polarized lenses with rotationally symmetric aspherical surfaces without compromising the advantages of aspherical lenses, achieving a thickness comparable to normal lenses while maintaining the polarization function.

Implementation Method 1

a polarized lens for spectacles which blocks light of a predetermined polarization direction that has been reflected by a water surface or the like

Methodology Applied
Scientific EffectPolarization: Polarisation

Data Source

PatentEP4056356A1Polarized lens for spectacles, method for manufacturing polarized lens for spectacles, method for manufacturing framed spectacle, and method for inspecting polarized lens for spectacles
Publication Date: 2022.09.14 HOYA LENS THAILAND LTD
  • EP4056356A1 patent drawingFigure 1A~1D
  • EP4056356A1 patent drawingFigure 2
  • EP4056356A1 patent drawingFigure 3~4

AI summary

Provided is a technique by which it is possible to reduce the thickness of a polarized lens for spectacles that has a rotationally symmetric aspherical surface formed on an object-side surface thereof, in the same manner as for a normal lens. Provided is a polarized lens for spectacles, including: a first lens substrate (110) having an object-side surface (111) on which a convex surface that is a rotationally symmetric aspherical surface is formed; a second lens substrate (120) having an eyeball-side surface; and a polarized film (130) disposed between the first lens substrate and the second lens substrate and having a convex shape toward the object-side surface, wherein an in-plane distribution of a distance W between the object-side surface of the first lens substrate and the polarized film is concentric with the optical center of the lens and where the distance W is rotational symmetric as well.