Matrix Photodiode Laser Spot Detector Using Indium Ball Hybridization
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Solution Overview
Problem
Existing laser spot detectors face challenges with sensitivity and precision, particularly as the observed field size increases, leading to noise and reduced sensitivity, and current matrix technologies require complex electronics and large pixel sizes, limiting measurement precision.
Innovation Solution
A laser spot detector with a matrix of photodiodes hybridized on a readout circuit using flexible conducting balls, allowing the photodiodes to function as a single large photodiode for fast detection and precise location of laser spots with sub-pixel precision, utilizing a weighing technique to calculate the barycenter and optimizing integration time for reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the observed field size increases, then the detection coverage improves, but the noise increases and sensitivity decreases
Solution Approach 1:
The device segments the observed field into multiple independent detection zones using a matrix of photodiodes, where each photodiode can independently detect laser spots. This segmentation allows the system to maintain high sensitivity in each small detection zone while covering a large overall field, resolving the contradiction between field size and sensitivity.
2Measurement precision
If matrix technologies are used to improve precision and sensitivity, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
The invention extracts and removes the complex electronics from each pixel, retaining only the simple photodiode detection elements in the matrix. The readout circuit processes signals from multiple photodiodes simultaneously, achieving high precision position measurement without requiring complex electronics at each pixel location, thus reducing overall device complexity and cost.
3Adaptability or versatility
If intelligent pixels with inherent electronics are used, then the detection capability improves, but the pixel size increases beyond 50 μm, limiting measurement precision
Solution Approach 1:
The invention moves the electronic processing functionality from the pixel dimension to the readout circuit dimension. The photodiodes in the matrix serve purely as detection elements with small sizes, while the readout circuit located elsewhere performs the complex signal processing and coordination functions, enabling small pixel sizes while maintaining high detection capability.
4Reliability
If continuous reading of pixels over long integration times is performed, then the laser pulse detection capability improves, but the noise increases and sensitivity decreases
Solution Approach 1:
The readout circuit performs periodic sampling of the photodiode signals at optimized time intervals rather than continuous reading. This periodic action allows the system to detect laser pulses effectively while minimizing the integration time for each sample, thereby reducing noise accumulation and maintaining high sensitivity.
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 enhances the signal-to-noise ratio, allows detection over larger fields with improved precision and reduced cost, and maintains high sensitivity without the need for complex electronics or large pixel sizes.
Implementation Method 1
a matrix of photodiodes produced on a single substrate, said photodiodes each comprising an individual electrode (12)
Data Source
AI summary
In the field of deviometers used for detecting and locating laser spots, and more precisely to a laser spot detector with matrix deviometer, a device comprises a readout circuit exhibiting a matrix of pixels, a matrix of photodiodes produced on a single substrate, said photodiodes each comprising an individual electrode, and a laser pulse detection device. The particular feature of the device resides in the fact that said matrix of photodiodes is hybridized on said readout circuit by way of balls made of flexible and conducting material, such as indium, placed in contact with the pixels of the readout circuit, so that said single substrate constitutes an electrode common to the set of photodiodes and that said individual electrodes are linked to said pixels by said balls.