Wafer-Level Phase Detection Using Segmented Diffraction Element
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Solution Overview
Problem
Existing phase detection methods for wafer-level optical elements are inefficient due to the need to cut optical elements into individual components for separate detection, resulting in low detection efficiency and accuracy.
Innovation Solution
A phase detection device and method that includes a light source, beam collimator, diffraction element, and imaging detector, where the diffraction element has a mesh mask region and an array region to produce interference between diffracted lights, even with incoherent light sources, thereby improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single optical element is used for phase detection, then the detection accuracy is improved, but the detection efficiency deteriorates due to the need to cut wafer-level optical elements into individual components
Solution Approach 1:
The diffraction element is segmented into a mesh mask region and an array region, where the array region contains multiple cells that process different portions of the optical element simultaneously. This segmentation allows parallel processing of multiple regions without requiring physical cutting of the optical element, thus maintaining detection accuracy while improving efficiency.
Solution Approach 2:
Multiple detection functions are merged into a single wafer-level optical element detection process. The diffraction element integrates multiple diffraction orders that simultaneously capture phase information from different regions of the optical element, enabling comprehensive phase detection without sequential cutting and separate measurements.
2Measurement precision
If a light source with high coherence is used, then the interference pattern is enhanced, but noisy speckles are produced in the interference image
Solution Approach 1:
The coherence parameter of the light source is changed from high coherence to low coherence. This parameter change reduces the formation of noisy speckles in the interference image while the diffraction element's specific structure compensates to maintain sufficient interference contrast for accurate phase detection.
Solution Approach 2:
The diffraction element acts as an intermediary that enables interference patterns to form even with low coherence light sources. The mesh mask region and array region structure facilitates the creation of sufficient interference between diffracted lights without requiring high coherence, thereby eliminating speckle noise while preserving measurement capability.
3Measurement precision
If wafer-level optical elements are cut into individual components, then the phase detection can be performed on each element, but the detection process becomes time-consuming and inefficient
Solution Approach 1:
The diffraction element is segmented into multiple functional regions (mesh mask region and array region with multiple cells) that can simultaneously process different areas of the wafer-level optical element. This allows parallel phase detection across multiple regions without physical cutting, significantly reducing detection time while maintaining precision.
Solution Approach 2:
The detection process maintains continuity by allowing the entire wafer-level optical element to remain intact while undergoing comprehensive phase detection. The light beam continuously illuminates the entire element, and the diffraction element continuously captures phase information from all regions simultaneously, eliminating the time loss associated with cutting and sequential detection.
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 solution enhances the accuracy of phase detection for wafer-level optical elements by utilizing incoherent light sources, reducing noisy speckles, and allowing for comprehensive phase detection without the need to cut optical elements into individual components.
Implementation Method 1
a diffraction element and an imaging detector; the diffraction element includes a mesh mask region and an array region
Implementation Method 2
the diffracted lights from the diffraction element can produce enough interference between each other
Data Source
AI summary
A phase-detection device and method for an optical element are provided, along the direction of the optical path the phase-detection device includes: a light source, a beam collimator, a diffraction element and an imaging detector; the optical element is set between the filter and the diffraction element; the diffraction element includes a mesh mask region and an array region segmented by the mesh mask region; mesh mask region blocks lights of a target wavelength; the array region includes a first class of cell and a second class of cell, and the first class of cell and the second class of cell are alternatively arranged; the first class of cell provides a first phase for the lights of target wavelength, and the second class of cell provides a second phase for lights of target wavelength; a phase difference between the first phase and second phase is T rad.