Light receiver and method for reading out avalanche photodiodes in Geiger mode

Patent metadata

Field	Value
Publication number	US-10612972-B2
Application number	US-201715846296-A
Country	US
Kind code	B2
Filing date	Dec 19, 2017
Priority date	Dec 22, 2016
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A light receiver ( 100 ), comprising:
a plurality of avalanche photodiode elements ( 10 ) each being biased with a bias voltage above a breakdown voltage and thus operated in a Geiger mode in order to trigger a Geiger current upon light reception
and a plurality of readout circuits ( 42, 44, 46 ) associated with individual avalanche photodiode elements ( 10 ) or a group of avalanche photodiode elements ( 10 ) for reading out a Geiger current generated upon light reception,
wherein the readout circuits ( 42, 44, 46 ) each comprise a measurement path ( 42 ) and a blanking path ( 46 ) as well as a switching element ( 44 ) for selectively supplying the Geiger current, or a measurement current corresponding to the Geiger current, to the measurement path ( 42 ) or the blanking path ( 46 ).

First claim

The invention claimed is:

1. A light receiver ( 100 ), comprising:
a plurality of avalanche photodiode elements ( 10 ) each being biased with a bias voltage above a breakdown voltage and thus operated in a Geiger mode in order to trigger a Geiger current upon light reception; and
a plurality of readout circuits ( 42 , 44 , 46 ) associated with individual avalanche photodiode elements ( 10 ) or a group of avalanche photodiode elements ( 10 ) for reading out a Geiger current generated upon light reception,
wherein the readout circuits ( 42 , 44 , 46 ) each comprise a measurement path ( 42 ) and a blanking path ( 46 ) as well as a switching element ( 44 ) for selectively supplying the Geiger current, or a measurement current corresponding to the Geiger current, to the measurement path ( 42 ) or the blanking path ( 46 ) to switch regions of the light receiver ( 100 ) to the blanking path ( 46 ), such that the regions are muted or at least evaluated in a different manner than the avalanche photodiode elements ( 10 ), the readout circuits ( 42 , 44 , 46 ) thereof being connected to the measurement path ( 42 ).

2. The light receiver ( 100 ) according to claim 1 ,
wherein the switching element ( 44 ) is a readout transistor ( 48 ).

3. The light receiver ( 100 ) according to claim 1 ,
wherein the blanking path ( 46 ) is configured to let the Geiger current or the measurement current be drained without reading out.

4. The light receiver ( 100 ) according to claim 1 ,
wherein a signal detection circuit ( 12 ) is provided for the readout circuit ( 42 , 44 , 46 ) and the associated individual avalanche photodiode element ( 10 ) or the associated group of avalanche photodiode elements ( 10 ), the signal detection circuit ( 12 ) comprising an active coupling element ( 32 ) having an input ( 34 ) connected to the avalanche photodiode elements ( 10 ) and an output ( 36 ) which maps the Geiger current at the input ( 34 ) to the measurement current corresponding to the Geiger current in its course and level, wherein the input ( 34 ) forms a virtual short-circuit for the Geiger current to a potential (ground; −U BE ; U const −U BE ) and the output ( 36 ) is decoupled from the input ( 34 ).

5. The light receiver ( 100 ) according to claim 4 ,
wherein the coupling element ( 32 ) comprises one signal detection transistor.

6. The light receiver ( 100 ) according to claim 5 ,
wherein the base voltage of the signal detection transistor is adaptable for switching between the measurement path ( 42 ) and the blanking path ( 46 ).

7. The light receiver ( 100 ) according to claim 4 ,
wherein the readout circuit ( 42 , 44 , 46 ) is connected to the input ( 34 ).

8. The light receiver ( 100 ) according to claim 7 ,
wherein the readout circuit ( 42 , 44 , 46 ) comprises only one readout transistor ( 48 ).

9. The light receiver ( 100 ) according to claim 8 ,
wherein the base voltage of the readout transistor ( 48 ) is adaptable for switching between the measurement path ( 42 ) and the blanking path ( 46 ).

10. The light receiver ( 100 ) according to claim 4 ,
wherein the readout circuit ( 42 , 44 , 46 ) is connected to the output ( 36 ).

11. The light receiver ( 100 ) according to claim 10 ,
wherein the coupling element ( 32 ) comprises a signal detection transistor, and wherein the readout circuit ( 42 , 44 , 46 ) comprises at least two parallel readout transistors ( 48 a - b ) each in a cascode circuit with the signal detection transistor.

12. The light receiver ( 100 ) according to claim 1 ,
wherein the blanking path ( 46 ) comprises a measurement tap.

13. The light receiver ( 100 ) according to claim 1 ,
wherein the readout circuit ( 42 , 44 , 46 ) comprises at least one further measurement path ( 52 ).

14. The light receiver ( 100 ) according to claim 13 ,
wherein measurement path ( 42 ) and further measurement path ( 52 ) each have a measurement tap, the measurement taps having different attenuations of the Geiger current or the measurement current.

15. The light receiver ( 100 ) according to claim 14 ,
wherein measurement path ( 42 ) and further measurement path ( 52 ) comprise a voltage attenuation circuit or different working impedances.

16. The light receiver ( 100 ) according to claim 1 ,
wherein the avalanche photodiode elements ( 10 ) comprise an electrode ( 28 ) for providing the Geiger current with capacitive coupling, and wherein the readout circuit ( 42 , 44 , 46 ) is connected to the electrode ( 28 ).

17. An optoelectronic sensor having at least one light receiver ( 100 ), the light receiver ( 100 ) comprising:
a plurality of avalanche photodiode elements ( 10 ) each being biased with a bias voltage above a breakdown voltage and thus operated in a Geiger mode in order to trigger a Geiger current upon light reception; and
a plurality of readout circuits ( 42 , 44 , 46 ) associated with individual avalanche photodiode elements ( 10 ) or a group of avalanche photodiode elements ( 10 ) for reading out a Geiger current generated upon light reception,
wherein the readout circuits ( 42 , 44 , 46 ) each comprise a measurement path ( 42 ) and a blanking path ( 46 ) as well as a switching element ( 44 ) for selectively supplying the Geiger current, or a measurement current corresponding to the Geiger current, to the measurement path ( 42 ) or the blanking path ( 46 ) to switch regions of the light receiver ( 100 ) to the blanking path ( 46 ), such that the regions are muted or at least evaluated in a different manner than the avalanche photodiode elements ( 10 ), the readout circuits ( 42 , 44 , 46 ) thereof being connected to the measurement path ( 42 ).

18. The optoelectronic sensor according to claim 17 ,
the sensor being configured as a sensor for measuring distances according to a time of flight method.

19. The optoelectronic sensor according to claim 17 ,
the sensor being configured as a code reader.

20. The optoelectronic sensor according to claim 17 ,
the sensor being configured for data transmission.

21. A method for reading out avalanche photodiode elements ( 10 ), each being biased with a bias voltage above a breakdown voltage and thus operated in a Geiger mode, wherein the avalanche photodiode elements ( 10 ) trigger a Geiger current upon light reception and wherein the Geiger current from individual avalanche photodiode elements ( 10 ) or groups of avalanche photodiode elements ( 10 ) is read out, and wherein the Geiger current, or a measurement current corresponding to the Geiger current, is selectively supplied to a measurement path ( 42 ) or to a blanking path ( 46 ) by switching a switching element ( 44 ) to switch regions of a light receiver ( 100 ) to the blanking path ( 46 ), such that the regions are muted or at least evaluated in a different manner than the avalanche photodiode elements ( 10 ), readout circuits ( 42 , 44 , 46 ) thereof being connected to the measurement path ( 42 ).

Assignees

• Sick Ag

Inventors

• Clemens Klaus
• Hug Gottfried
• Seitz Stefan

Classifications

• G01S17/89

  for mapping or imaging · CPC title

• G01J2001/4238

  Pulsed light · CPC title

• G01J1/44 Primary

  Electric circuits {(for command of an exposure part G03B7/02)} · CPC title

• G01J2001/442

  Single-photon detection or photon counting · CPC title

• G01S7/4868

  Controlling received signal intensity or exposure of sensor · CPC title