Laminated Diffractive Optical Element for Endoscope Flare Reduction
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Solution Overview
Problem
Diffractive optical elements face issues such as wavelength-dependent diffraction efficiency leading to flare in endoscopes, difficulty in mass production due to glass materials, and manufacturing challenges like warping and separation with resin-based elements.
Innovation Solution
A diffractive optical element is formed by laminating two optical material layers of different energy-cured resins with a relief pattern at their interface, adhering to specific thickness and refractive index ratios to enhance diffraction efficiency and processability while reducing warping and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a diffractive optical element is made of resin for easy manufacturing and low cost, then ease of manufacture and productivity are improved, but warping and separation occur during manufacturing processes
Solution Approach 1:
The patent applies composite materials by combining two different resins (first resin and second resin) with distinct properties. The first resin provides structural stability during manufacturing, while the second resin enables proper curing and adhesion. This composite approach allows the element to be manufactured without warping or separation while maintaining ease of production and low cost associated with resin-based materials.
2Loss of energy
If optical elements with relief patterns are laminated to achieve high diffraction efficiency in wide wavelength range, then diffraction efficiency is improved, but processing becomes difficult and mass production becomes expensive due to glass material
Solution Approach 1:
The patent changes the material parameter from traditional glass to resin, which fundamentally alters the processing characteristics. Resins can be molded and cured more easily than glass, enabling mass production through injection molding or similar processes. The relief pattern is formed during the molding process itself rather than requiring subsequent complex processing steps, thus maintaining high diffraction efficiency while dramatically improving ease of manufacture and reducing costs.
3Device complexity
If a single-layer diffractive optical element is used for simple structure, then device complexity is reduced, but diffraction efficiency becomes strongly wavelength-dependent causing flare
Solution Approach 1:
The patent uses a composite structure with two different resins having different refractive indices and curing characteristics. The first resin layer provides a base structure, while the second resin layer with its different optical properties compensates for wavelength-dependent diffraction effects. This composite approach broadens the effective wavelength range and reduces flare while maintaining a relatively simple laminated structure that can still be manufactured efficiently.
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 increases diffraction efficiency across a wide wavelength range, reduces manufacturing costs, and minimizes warping and separation issues, ensuring high-quality performance in endoscopes.
Implementation Method 1
a diffractive optical element which is formed by laminating two optical material layers formed of different energy-cured resins; in which a relief pattern is formed at an interface between the two optical material layers
Implementation Method 2
two optical material layers formed of different energy-cured resins
Data Source
AI summary
Provided is a diffractive optical element that is formed by laminating two optical material layers formed of different energy-cured resins; in which a relief pattern is formed at the interface between the two optical material layers; and that satisfies the following conditional expressions: 0.01<d2/d1<0.2(1) 0.05<d1/phiE<1.0(2) 0.0005<d2/phiE<0.1(3) wherein d1 is the center plate thickness (mm) of one optical material layer 2 that is cured first, d2 is the center plate thickness (mm) of the other optical material layer 3 that is cured later, and phiE is the effective diameter (mm) of the relief pattern 4.