Device for detecting a laser spot

Patent metadata

Field	Value
Publication number	US-10670703-B2
Application number	US-201716079690-A
Country	US
Kind code	B2
Filing date	Feb 24, 2017
Priority date	Feb 29, 2016
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

Abstract

Laser spot detecting device including a plurality of elementary optoelectronic detectors that are each connected to an elementary pulse detecting circuit, each elementary pulse detecting circuit including a comparator and a memory module that is connected to one output of the comparator, the memory modules being connected to a multiplexing circuit having an output forming a digital spatial output of the laser spot detecting device. The laser spot detecting device further more includes a global OR circuit 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.

First claim

The invention claimed is:

1. A laser spot detecting device, comprising a matrix optical sensor having a plurality of elementary optoelectronic detectors each connected to a pulse detecting elementary circuit, with each pulse detecting elementary circuit comprising a comparator for comparing with a threshold an electrical quantity depending on an output current of the elementary optoelectronic detector applied to an input of the comparator and a memory module connected to an output of the comparator, with the memory modules being connected to a multiplexing circuit having an output forming a digital spatial output of the laser spot detecting device, characterized in that the laser spot detecting device further comprises a global OR circuit having inputs connected to the comparator outputs and having an output forming a real time digital temporal output of the laser spot detecting device.

2. The device according to claim 1 , wherein the global OR circuit comprises a plurality of open drain transistors, with each open drain transistor being connected to an output of a comparator of one of the pulse detecting elementary circuits and forming an open drain output of this pulse detecting elementary circuit.

3. The device according to claim 2 , wherein the open drain outputs of the pulse detecting elementary circuits connected to the elementary optoelectronic detectors located on a same line of the matrix sensor are connected together for summing said open drain outputs, and thus form a line signal (S 1 ).

4. The device according to claim 3 , wherein the global OR circuit further comprises components arranged for summing together the line signals and thus form the temporal output of the spot laser detecting device.

5. The device according to claim 1 , wherein an input of the comparator of each pulse detecting elementary circuit is connected to the memory module, and wherein the output of the multiplexing circuit also forms an analog spatial output of the detecting device.

6. The device according to claim 5 , wherein each memory module includes a first memory and a second memory.

7. The device according to claim 6 , wherein each pulse detecting elementary circuit further comprises a selector having as inputs the comparator input and the comparator output and having an output connected to the first memory and to the second memory.

8. The device according to claim 6 , wherein the first memory and/or the second memory comprise(s) a sample and hold circuit.

9. A method for detecting a laser spot implemented by a laser spot detecting device according to claim 1 , with said method for detecting a laser spot comprising a verification step in which the temporal output of the laser spot detecting device is used for determining a duration of a laser pulse and/or a period of time between two successive laser pulses.

10. The detection method according to claim 9 , wherein the duration of a laser pulse and/or the period of time between two successive laser pulses is/are used to verify that the laser pulse actually corresponds to a target laser spot.

11. The method according to claim 9 , wherein, as the device is provided with an analog spatial output, the analog spatial output is used when several digitized laser pulses have a consistent width and a consistent length between two successive digitized pulses for radiometry discriminating for distinguishing the valid digitized laser pulses and the parasitic digitized laser pulses.

12. The method according to claim 9 , with each memory module having a first memory and a second memory each comprising a sample and hold circuit, with each pulse detecting elementary circuit further comprising a selector having as inputs the comparator input and the comparator output and having an output connected to the first memory and to the second memory, with the sample and hold circuits being controlled for storing the either digital or analog laser pulses.

Assignees

• Safran Electronics & Defense

Inventors

• Martinez Alain

Classifications

• G01J11/00

  Measuring the characteristics of individual optical pulses or of optical pulse trains · CPC title

• H03K5/2472

  using field effect transistors (H03K5/2436 takes precedence) · CPC title

• G01S3/784 Primary

  using a mosaic of detectors · CPC title

• G01R19/16528

  using digital techniques or performing arithmetic operations (using digital techniques to measure a voltage or a current, see G01R19/25) · CPC title

• G01S7/4863 Primary

  Detector arrays, e.g. charge-transfer gates · CPC title