Diffractive Optical Element Grating Line Continuity
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Solution Overview
Problem
Current diffractive elements with fixed-sized grating pixels suffer from reduced brightness and discontinuous grating lines, leading to reduced radiation intensity and angular scattering, especially as pixel size decreases, due to inefficient recording methods and limitations in controlling grating line phase and position.
Innovation Solution
A method of forming a diffractive element using rectangular grating pixels with varying sizes and tilts, ensuring that grating lines of adjacent pixels with the same period and tilt continue through their common boundary, achieved by selecting optimal dimensions for each pixel to maintain continuity and maximize brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size is decreased to increase resolution, then the resolution is improved, but the brightness of the diffractive image is reduced
Solution Approach 1:
The patent applies local quality by allowing grating pixels to have variable sizes rather than uniform sizes. Specifically, pixels are sized such that those with the same grating period and tilt have dimensions that make their grating lines continuous across boundaries. This local adaptation of pixel size to grating parameters maintains brightness by ensuring continuous grating structures while still achieving high resolution through the overall fine pixel grid.
2Ease of manufacture
If fixed-sized grating pixels are used, then the manufacturing is simplified, but discontinuities in grating lines occur at pixel boundaries
Solution Approach 1:
The patent changes the parameter of pixel size from a fixed constant to a variable parameter that depends on the grating period and tilt angle. By calculating optimal pixel dimensions based on these grating parameters, the invention ensures that grating lines continue continuously across pixel boundaries. This parameter adaptation maintains manufacturing precision for line continuity while the systematic calculation method keeps the manufacturing process manageable.
3Device complexity
If grating pixels with the same period and tilt are arranged adjacent to each other, then the diffractive image composition is simplified, but grating line continuity cannot be ensured
Solution Approach 1:
The patent applies local quality by making pixel size dependent on local grating parameters (period and tilt). When pixels with the same grating parameters are arranged adjacent to each other, they are given specific dimensions that ensure continuous grating lines. This local adaptation allows simplified image composition with repeated pixel patterns while maintaining precise grating line continuity through the calculated pixel dimensions.
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 enhances the brightness and radiation capabilities of diffractive images by eliminating discontinuities in grating lines, resulting in improved image quality and design flexibility, even at higher resolutions.
Implementation Method 1
exposing a set of diffractive pixels having inner grating structures directly on an area of a recording medium, such as a photoresist or electron resist
Implementation Method 2
A diffraction grating decomposes incoming white light into a spectrum of colours, and at the same time it changes the direction of its propagation
Data Source
AI summary
A diffractive element (2) that comprises a set of rectangular grating pixels (1) with a grating structure of grating period (D) and grating tilt (a), whilst at least some grating pixels (1) have different grating period (D) and/or different grating tilt (a) and at least some grating pixels (1) are in direct contact with each other. The set of grating pixels (1) comprises grating pixels (1) generally of various dimensions (Lx) and (Ly), whilst the dimensions (Lx) and (Ly) of the grating pixels (1) with the same grating period (D) and the same grating tilt (a) are such that the lines of the grating structures of these adjacent grating pixels (1) with the same grating period (D) and the same grating tilt (a) continue on through their common boundary. Additionally, a method of creation of the diffractive element (2) is described herein.