Diffractive Optical Element with Non-Circular Annular Sections
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Solution Overview
Problem
Existing diffractive optical elements (DOEs) face challenges in achieving high diffraction efficiency over the visible range while maintaining cost-effectiveness and moldability, with previous solutions either being expensive due to complex molding processes or prone to molding failures due to miniaturization techniques like the D-cut shape.
Innovation Solution
A DOE design featuring concentric annular sections with non-circular shapes, where the first and second diffraction gratings made of different materials are layered, with specific inequalities governing the relationship between the array pitch, grating height, and radius to optimize diffraction efficiency and moldability, allowing for low-cost manufacturing and improved chromatic aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diffraction gratings are formed on a substrate using a mold with multiple molding processes, then diffraction efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple diffraction gratings made of different materials into a single integrated mold structure, allowing simultaneous formation of all gratings in one molding process rather than requiring separate molding steps for each grating layer
Solution Approach 2:
The invention uses composite materials by forming diffraction gratings from multiple different materials within a single molded diffractive optical element, achieving high diffraction efficiency across the visible spectrum while maintaining cost-effective single-step manufacturing
2Volume of moving object
If the lens is partially cut for miniaturization (D-cut shape), then device size is reduced, but molding process reliability deteriorates
Solution Approach 1:
The patent performs preliminary design of the diffractive area shape and array pitch distribution to ensure moldability is maintained from the outset, rather than attempting to correct molding issues after the D-cut miniaturization is implemented
Solution Approach 2:
The invention optimizes the array pitch parameters and diffractive area geometry to satisfy specific inequalities that balance miniaturization requirements with molding process reliability, allowing the D-cut shape to be maintained without causing molding failures
3Reliability
If the array pitch is reduced to increase diffraction efficiency, then diffraction efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the array pitch parameters and their distribution across the diffractive area to satisfy specific inequalities that balance miniaturization requirements with molding process reliability
Solution Approach 2:
By using multiple different materials with varying refractive indices and dispersion properties, the patent achieves high diffraction efficiency with more relaxed array pitch tolerances, as the composite structure compensates for manufacturing variations
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 proposed DOE achieves high diffraction efficiency across the visible range, enhances moldability, and reduces the size of optical systems by optimizing the array pitch and grating configuration, thereby addressing the limitations of previous designs.
Implementation Method 1
a diffractive area including a plurality of concentrically arranged annular sections... achieves high diffraction efficiency across the visible range
Implementation Method 2
the first and second diffraction gratings made of different materials are layered... improves chromatic aberration correction
Data Source
AI summary
A diffractive optical element includes a diffractive area including annular sections concentrically arranged. At least one of the annular sections has a non-circular shape. A predetermined inequality is satisfied.