Pixelated Color and Polarization Masks for Dynamic Interferometry
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Solution Overview
Problem
Existing interferometric measurement systems using pixelated polarization masks are limited in the information they can provide about a surface under test due to the number of detected variables being constrained by the number of input signals received by the sensor, which restricts the gathering of additional characteristics of the test object.
Innovation Solution
Combining a pixelated polarization mask with a pixelated color-filter mask or detector capable of distinguishing between different colors, allowing for the detection of multiple wavelengths and additional information about the sample, such as motion, autofocus, and color imaging, to enhance the capability of dynamic interferometry systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pixelated polarization mask is used for dynamic interferometry, then vibration-immune measurements are achieved with single camera frame acquisition, but the number of detected variables is limited by the number of input signals received by the sensor
Solution Approach 1:
The invention segments the detection capability by dividing the sensor array into multiple pixel groups, where each group is associated with a different wavelength band. This segmentation allows simultaneous detection of multiple wavelengths across different pixel groups within a single camera frame, thereby increasing the number of detected variables without requiring multiple frames or additional sensors.
Solution Approach 2:
The invention adds a wavelength dimension to the traditional spatial detection approach. By incorporating wavelength-selective bandpass filters at different pixel locations, the system detects not only spatial interference patterns but also spectral information, effectively transforming a 2D spatial detection problem into a 3D detection problem that includes wavelength as the third dimension.
2Loss of information
If multiple wavelengths are detected simultaneously, then additional information about the sample is obtained, but the device complexity increases
Solution Approach 1:
The invention merges the wavelength selection function and the interference detection function into a single integrated optical path. By placing wavelength-selective bandpass filters directly in front of pixel groups within the same camera sensor, the system combines spectral filtering and spatial interferometry in one device, avoiding the need for separate wavelength selection optics or multiple cameras.
Solution Approach 2:
The invention creates a universal measurement system that can simultaneously perform multiple measurement functions using a single camera frame. Different pixel groups detect different wavelength bands, enabling the system to gather surface height information, material composition data, and other characteristics all at once, making the device multi-functional without requiring separate measurement systems for each function.
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
Enables the acquisition of additional information about the sample, including high-speed autofocus, tip/tilt feedback, and extended-range phase shifting interferometry, with a single camera frame, providing vibration-immune measurements and enabling the creation of realistic 3D representations without the need for scanning.
Implementation Method 1
pixelated polarization mask
Implementation Method 2
pixelated color-filter mask comprises a wavelength-selective bandpass filter placed in front of each camera pixel
Implementation Method 3
each pixel consists of stacked photodiodes, each capable of detecting and separately measuring a different color or wavelength band
Implementation Method 4
interferometry with pixelated color discriminating elements combined with pixelated polarization masks
Data Source
AI summary
A pixelated color mask is combined with a pixelated polarization mask in dynamic interferometry. The color mask includes a wavelength-selective bandpass filter placed in front of each camera pixel such that each set of contiguous four camera pixels is covered by two green bandpass filters, a red bandpass filter, and a blue bandpass filter. The pixelated phase mask is coupled to the color filters such that one polarization filter covers one set of color filters. At least three polarization filters are used to calculate phase. In addition, the color signals can be used, for example, to encode the motion of the interferometer, to provide very high speed autofocus or tip/tilt feedback, to create a color image of the object being measured, to automatically focus the system at different positions for different measurements conducted with different color sources, and to perform heterodyne interferometry with a single, vibration-immune measurement.