Polarizer Matrix for Polarization-Independent Light Source Measurement
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Solution Overview
Problem
Existing measuring systems for light sources, particularly VCSEL elements, suffer from systematic errors due to polarization-dependent image sensors, leading to inaccurate absolute output measurements with error budgets exceeding 10%, and existing depolarizers fail to adequately address polarization issues, limiting spatial resolution.
Innovation Solution
A matrix of linear polarizers, rotated relative to each other, is integrated in front of image sensors to compensate for polarization sensitivity, combined with a spectral measuring device and micro lenses to enhance precision and reduce noise, allowing for polarization-independent absolute output measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If depolarizers are used to eliminate polarization of light from VCSEL elements, then polarization effects are reduced, but spatial resolution deteriorates due to birefringent properties and narrow spectrum
Solution Approach 1:
The image sensor array is divided into matrix blocks where adjacent sensors have different polarizer orientations (e.g., 0°, 45°, 90°, 135°). This segmentation allows each sensor element to measure light with a specific polarization angle, and combining measurements from all orientations eliminates polarization dependence while preserving spatial resolution through the segmented sensor architecture.
Solution Approach 2:
Different regions of the image sensor array are equipped with polarizers having different transmission directions. Each local region (sensor element) has a specific polarization sensitivity, and the overall measurement is obtained by combining data from all regions with different local polarization characteristics, thereby achieving polarization-independent measurement without compromising spatial resolution.
2Manufacturing precision
If a single polarizer orientation is used in front of image sensors, then spatial resolution is maintained, but measurement accuracy deteriorates due to polarization-dependent sensitivity
Solution Approach 1:
The solution adds a polarization dimension to the measurement by incorporating multiple polarizer orientations across the image sensor array. Instead of measuring only intensity at each pixel, the system measures intensity across multiple polarization states, adding a new dimension of information that enables compensation for polarization effects while maintaining spatial resolution through the multi-dimensional measurement approach.
Solution Approach 2:
The transmission direction parameter of the polarizers is varied across different sensor elements in the array. By changing this parameter (polarizer angle) across the spatial dimension of the sensor array, the system captures polarization information without sacrificing spatial resolution, as each parameter change is mapped to a different spatial location in the measurement matrix.
3Measurement precision
If polarization compensation methods are implemented, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The image sensor array itself performs the polarization compensation function by having different sensors equipped with polarizers at different orientations. The sensors serve dual purposes: capturing spatial information and measuring polarization states. This self-service approach eliminates the need for separate depolarizer components or complex external polarization compensation devices, thereby reducing overall system complexity while achieving polarization-independent measurements.
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 solution minimizes measurement errors by averaging polarization-dependent deviations, enabling precise, spatially-resolved absolute output determination of light sources with reduced polarization sensitivity, effectively overcoming previous limitations in error budgets and maintaining high spatial resolution.
Implementation Method 1
a linear polarizer is associated with each of the image sensors, wherein the linear polarizers are arranged in the form of a matrix in front of the image sensors and two or more, preferably four, polarizers form a matrix block, wherein the transmission directions of adjacent linear polarizers within a matrix block are rotated relative to one another, preferably by 45° or by 90°
Implementation Method 2
the light is captured by the image sensors, wherein each image sensor converts the light that is incident on the image sensor into a measurement signal
Implementation Method 3
the light source emits light which is focused on the image sensors of the camera by the microscope optics
Data Source
AI summary
The present disclosure relates to a measuring system for measuring a light source in a polarization-independent manner, having a camera comprising a plurality of image sensors arranged in the form of a matrix, and a microscope optics, and to a method for measuring the light sources in a polarization-independent manner. The aim is to make it possible to measure the light output of the light source in an improved, simple and largely polarization-independent manner while maintaining the spatial resolution in the microscopic range. To that end, the present disclosure proposes that a linear polarizer is associated with each of the image sensors, wherein the linear polarizers are arranged in the form of a matrix in front of the image sensors and two or more, preferably four, polarizers form a matrix block, wherein the transmission directions of adjacent linear polarizers within a matrix block are rotated relative to one another, preferably by 45° or by 90°. In the method according to the present disclosure, the measurement signals of the image sensors that are associated with the polarizers of the same matrix block are converted into light output measured values in order to obtain the desired polarization independence.