Infrared detection device and method

Patent metadata

Field	Value
Publication number	US-9562936-B2
Application number	US-201414584239-A
Country	US
Kind code	B2
Filing date	Dec 29, 2014
Priority date	Jan 8, 2014
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

Infrared detection device comprising at least one first bolometer able to detect at least a part of infrared radiation intended to be received by the infrared detection device, and a reading and compensation circuit of a first electrical signal intended to be outputted by the first bolometer, with the reading and compensation circuit comprising at least:
one second bolometer coupled electrically to the first bolometer and insensitive to the infrared radiation intended to be received by the infrared detection device; one first reading circuit of said first electrical signal from which is subtracted a second electrical signal intended to be outputted by the second bolometer; one second reading circuit of an electrical voltage at the terminals of the first bolometer and/or of an electrical voltage at the terminals of the second bolometer, comprising a plurality of switches.

First claim

The invention claimed is:

1. An infrared detection device comprising:
at least one first bolometer configured to detect at least a part of infrared radiation received by the infrared detection device; and
a reading and compensation circuit configured to operate on a first electrical signal outputted by the first bolometer, the reading and compensation circuit including:
one second bolometer coupled electrically to the first bolometer and insensitive to the infrared radiation received by the infrared detection device,
one first reading circuit configured to read said first electrical signal from which is subtracted a second electrical signal outputted by the second bolometer, and
one second reading circuit configured to read at least one of an electrical voltage at terminals of the at least one first bolometer or an electrical voltage at terminals of the second bolometer,

wherein the first reading circuit includes at least one first operational amplifier configured to carry out an integration of a first current that passes through the first bolometer, corresponding to the first electrical signal, and from which is subtracted a second current, corresponding to the second electrical signal, that passes through the second bolometer, and
wherein the second reading circuit includes a plurality of switches configured to electrically connect, in a first configuration, a first input of the first operational amplifier to an electrical connection that connects the first bolometer to the second bolometer, and to electrically connect, in a second configuration, a second input of the first operational amplifier to one of the terminals of the first bolometer via one of the switches located in a pixel of the infrared detection device, the pixel including the first bolometer, and/or to one of the terminals of the second bolometer, and such that the first operational amplifier is mounted as an integrator in the first configuration and as a voltage follower in the second configuration.

2. The infrared detection device according to claim 1 , wherein the switches are configured to electrically connect, in the first configuration, the second input of the first operational amplifier to an electrical bias potential, and to electrically connect, in the second configuration, said electrical connection to the electrical bias potential.

3. The infrared detection device according to claim 1 , comprising:
a pixel array such that each pixel includes at least one first bolometer configured to detect a part of the infrared radiation received by the infrared detection device,
wherein each line or each column of pixels of the pixel array is coupled electrically to a reading and compensation circuit including:
one second bolometer electrically coupled to the first bolometers of said line or column of pixels and insensitive to the infrared radiation received by the infrared detection device,
one first reading circuit configured to read first electrical signals outputted by the first bolometers of said line or column of pixels from which is subtracted a second electrical signal outputted by the second bolometer, and
one second reading circuit configured to read an electrical voltage at terminals of the first bolometer via a switch located in a corresponding pixel and/or an electrical voltage at terminals of the second bolometer.

4. The infrared detection device according to claim 3 , wherein the second reading circuit is configured to read the electrical voltage at the terminals of the first bolometer via the switch located in the corresponding pixel and able to read the electrical voltage at the terminals of the second bolometer via a second switch located in the reading and compensation circuit.

5. The infrared detection device according to claim 1 , wherein:
the first bolometer includes a first terminal connected electrically to a first electrical supply potential, and a second terminal connected electrically to a source of a first MOS transistor;
the second bolometer includes a first terminal connected electrically to a first electrode of a second MOS transistor corresponding to a source of the second MOS transistor, and a second terminal connected electrically to a second electrical supply potential;
an input of the first reading circuit is connected electrically to a second electrode of the second MOS transistor corresponding to a drain of the second MOS transistor; and
an input of the second reading circuit is connected electrically to the second terminal of the first bolometer via a switch located in the pixel and/or to the first terminal of the second bolometer.

6. An infrared detection method implemented using an infrared detection device according to claim 5 , comprising:
polarizing the first MOS transistor and the second MOS transistor such that the first MOS transistor is in a resistance regime and that the second MOS transistor is in a blocked state, then
integrating, during a duration T, current passing through the first bolometer in a capacitor of value C coupled to the first operational amplifier, then
measuring an output voltage V out of the first operational amplifier, then
measuring, by the second reading circuit, a first electric potential V S1 at the second terminal of the first bolometer, then
calculating an electrical resistance R sens of the first bolometer such that:

R
sens

=



V
⁢

⁢
D
⁢

⁢
E
⁢

⁢
T

-

V

S
⁢

⁢
1

(

V
out

-

V
bus

)

×

C
T



,

with VDET: first electrical supply potential applied to the first terminal of the first bolometer;
V bus : electrical bias potential applied on an input of the first operational amplifier; and/or comprising:
polarizing the first MOS transistor and the second MOS transistor such that the first MOS transistor is in a blocked state and that the second MOS transistor is in a resistance regime, then
integrating, during a duration T, current passing through the second bolometer in the capacitor of value C c

Assignees

• Commissariat A L'Energie Atomique Et Aux Ene Alt
• Commissariat L Energie Atomique Et Aux Energies Alternatives

Inventors

• Becker Sebastien
• Hamelin Antoine

Classifications

• G01J5/20

  using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices · CPC title

• G01R27/02 Primary

  Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant (by measuring phase angle only G01R25/00) · CPC title

• G01J5/22 Primary

  Electrical features thereof · CPC title