Laser Spot Detector Circuit for Real-Time Pulse Timing

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Solution Overview

Problem

Matrix optical sensors can precisely determine the position of a laser spot but fail to provide temporal parameters associated with the laser pulse, necessitating the use of an external additional single-element sensor for time parameter measurement, which is not optimal.

Innovation Solution

A laser spot detection device incorporating a matrix optical sensor with elementary optoelectronic detectors connected to elementary pulse detection circuits, including comparators and memory modules, and a global OR circuit for real-time digital time output, which reduces noise and increases response speed without additional components or optical paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If an external additional single-element sensor is used to measure temporal parameters, then temporal parameters can be obtained, but the device complexity increases and noise increases

Engineering Contradiction:
Improvetemporal parametersVSAvoiddevice complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent combines the temporal parameter measurement function with the existing matrix optical sensor by adding a global OR circuit that processes signals from all pixels simultaneously. This merges the spatial detection capability with temporal parameter extraction, eliminating the need for a separate external sensor and reducing overall device complexity while maintaining the ability to obtain temporal parameters such as laser pulse duration and repetition period

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The matrix optical sensor is designed to perform multiple functions: spatial position detection of laser spots and temporal parameter measurement of laser pulses. The global OR circuit enables the same sensor array to extract temporal information from the combined output of all pixels, making the device universal and eliminating the need for additional specialized components

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Loss of information

If an external additional single-element sensor is used to measure temporal parameters, then temporal parameters can be obtained, but the noise increases

Engineering Contradiction:
Improvetemporal parametersVSAvoidnoise
Core Design Contradiction:
Loss of informationVSObject-affected harmful factors

Solution Approach 1:

By merging the temporal measurement function into the existing multi-pixel sensor array, the patent distributes the measurement function across multiple detectors rather than concentrating it in a single external sensor. This distribution reduces the impact of noise and background current, as each pixel contributes to the temporal parameter extraction while the global OR circuit processes the combined signal

Inventive Principle:
Principle #5Merging (Combining)

3Loss of information

If an external additional single-element sensor is used to measure temporal parameters, then temporal parameters can be obtained, but the response speed decreases

Engineering Contradiction:
Improvetemporal parametersVSAvoidresponse speed
Core Design Contradiction:
Loss of informationVSSpeed

Solution Approach 1:

The global OR circuit combines signals from all pixels in parallel, enabling simultaneous temporal parameter extraction across the entire sensor array. This parallel processing approach maintains high response speed by avoiding the sequential or time-multiplexed operations that would be required if using a separate external sensor, thus preserving the fast response characteristics of the original matrix sensor

Inventive Principle:
Principle #5Merging (Combining)

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 analysis of laser pulses for temporal parameters in real-time, improving noise reduction and response speed while maintaining performance comparable to spatial outputs, eliminating the need for external sensors.

Implementation Method 1

a photodetector for converting a laser light into an electrical signal

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3423860B1Device for detecting a laser spot
Publication Date: 2022.01.05 SAFRAN ELECTRONICS & DEFENSE (FR)
  • EP3423860B1 patent drawingFigure 1
  • EP3423860B1 patent drawingFigure 2~3
  • EP3423860B1 patent drawingFigure 4~6

AI summary

Laser-spot-detecting device (0) comprising a plurality of elementary optoelectronic detectors (1) that are each connected to an elementary pulse-detecting circuit (3), each elementary pulse-detecting circuit comprising a comparator and a memory module (26) that is connected to one output of the comparator, the memory modules being connected to a multiplexing circuit (35) having an output forming a digital spatial output of the laser spot detecting device. The laser spot detecting device furthermore includes a global OR circuit (21) having inputs connected to the outputs of the comparators and having an output forming a real-time digital temporal output of the laser-spot-detecting device. Method for detecting a laser spot implemented by such a detecting device.