Annular Diffractive Optical Element with Variable Pitch Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As the pitch of fine uneven structures in optical elements decreases to enhance diffraction efficiency, the aspect ratio increases, making it difficult to maintain the structure's shape and stability under external loads or changes in temperature and pressure.
Innovation Solution
The optical element features a plurality of annulus sections with first and second structures having different heights and widths in the radial direction, specifically designed to maintain a stable aspect ratio and phase modulation, while allowing for efficient light condensing or diverging effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the pitch of fine uneven structures is reduced to increase diffraction efficiency, then the light condensing effect is improved, but the aspect ratio of the structures increases making them difficult to form and maintain
Solution Approach 1:
The optical element is divided into multiple annular sections, each containing fine uneven structures. This segmentation allows the pitch to be reduced in specific regions while maintaining overall structural integrity through the distributed annular configuration
Solution Approach 2:
The pitch of the fine uneven structures is varied across different annular sections, with smaller pitch values in regions requiring higher diffraction efficiency and larger pitch values in regions where structural stability is prioritized. This local optimization resolves the contradiction between diffraction efficiency and manufacturability
2Use of energy by moving object
If the pitch of fine uneven structures is reduced to increase diffraction efficiency, then the light condensing effect is improved, but the structures become deformed by external factors such as load, temperature, and pressure
Solution Approach 1:
The pitch parameter of the fine uneven structures is optimized to balance diffraction efficiency and structural stability. By carefully selecting pitch values that are small enough to provide high diffraction efficiency but large enough to maintain aspect ratio within manufacturable and stable ranges, the contradiction between efficiency and reliability is resolved
3Use of energy by moving object
If the aspect ratio of fine uneven structures is increased to achieve smaller pitch, then the diffraction efficiency is improved, but the difficulty of forming and maintaining the structure increases
Solution Approach 1:
Different aspect ratios are employed in different annular sections of the optical element. Regions where high diffraction efficiency is critical use smaller pitch values with correspondingly higher aspect ratios, while other regions use larger pitch values with lower, more manufacturable aspect ratios
Solution Approach 2:
The pitch and aspect ratio parameters are systematically varied across the annular sections to optimize the balance between diffraction efficiency and ease of manufacture, allowing each region to operate at its optimal parameter set
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 design effectively suppresses the aspect ratio of the uneven structures, enhancing the stability and performance of the optical element, and achieving a light condensing effect equivalent to that of a diffractive optical element.
Implementation Method 1
an optical element (metalens) has conventionally been known that has a fine uneven (undulate, relief, or textured) structure formed on the surface of a substrate and provides a light condensing or diverging effect using diffraction
Data Source
AI summary
An optical element comprising a plurality of annulus sections concentrically arranged. The plurality of annulus sections include a first annulus section that includes a plurality of first structures each having a first height, and a plurality of second structures each having a second height different from the first height. The plurality of first structures have mutually different widths in a radial direction. The plurality of second structures have mutually different widths in the radial direction.