Laser-pulse Matrix Detector With Rapid Pulse Summation
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Solution Overview
Problem
Current matrix detectors face challenges in achieving high signal-to-noise ratio and high detection rates due to limitations in separating illumination and acquisition, leading to noise and loss of information between pulses, especially when detecting weak and recurrent light pulses.
Innovation Solution
A counter-reactive direct injection light pulse detector with a matrix of photodetectors, each comprising a MOSFET injection transistor, a cascoded inverting differential amplifier, and a demultiplexing circuit with phase-opposition controlled transistors for rapid shuttering, allowing for integration and summation of multiple pulses before reading, thereby reducing noise and increasing detection rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a long integration time is used to detect high-recurrence pulses, then the detection rate is improved, but the image contrast deteriorates due to integration of parasitic flux
Solution Approach 1:
The patent implements periodic shuttering of the detector synchronized with the laser pulse emission. The shutter is closed during laser emission and background illumination periods, and opened only during the brief window when backscattered target photons are expected. This periodic on/off action allows long integration times for high detection rates while maintaining image contrast by excluding parasitic flux during specific phases of the cycle.
2Measurement precision
If the detector is optically shuttered at each pulse emission to eliminate parasitic flux, then the image contrast is improved, but the detection rate is limited by sequential integration and reading
Solution Approach 1:
The patent maintains continuous integration of backscattered photons from the target across multiple laser pulses by keeping the shutter open during the entire integration period except during laser emission. This continuous accumulation of signal photons, combined with periodic shuttering to block parasitic flux, enables high detection rates while preserving image contrast.
3Object-affected harmful factors
If the integrator is kept under reset to carry out shuttering, then the parasitic flux is eliminated, but information loss occurs between pulses
Solution Approach 1:
The patent dynamically controls the integrator reset state based on the operational phase. During laser emission and background illumination periods, the integrator is reset to block parasitic flux. During the integration window when backscattered target photons are expected, the integrator is activated to accumulate signal. This dynamic switching between reset and integration states eliminates parasitic flux while preserving signal information.
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 high-rate pulse detection with improved signal-to-noise ratio by minimizing noise during post-integration and allowing operation at rates exceeding 20 kHz, reducing information loss between pulses and noise degradation.
Implementation Method 1
each photodetector of a matrix detector comprises a transducer such as a photodiode which converts the photons received into electrons in proportion to the illumination received
Data Source
Figure 1a~1b
Figure 2
Figure 3~4
AI summary
The invention relates to a light-pulse detector (100) with direct feedback injection which comprises a matrix of photodetectors, each photodetector comprising a transducer (1) and an integrator (2) having a MOSFET injection transistor (21) connected in common grid mode, a feedback amplifier and an integrating capacitor (22). The feedback amplifier is a cascoded inverting differential amplifier (20') placed between the input of the injection transistor (21) and the gate of this transistor, and, for each photodetector, a demultiplexing circuit (4) is inserted between the transducer (1) and the integrator (2). This circuit (4) is capable of connecting, in succession, the transducer (1) to the input of the inverting amplifier (20') and then to the input of the injection transistor (21).