Integrated electronic device for monitoring humidity and/or corrosion

• US 10,393,692 B2
• Filed: 03/22/2018
• Issued: 08/27/2019
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Pagani, Alberto, Murari, Bruno
• Primary Examiner(s): Reisner, Noam
• Application Number:
  US15/928,681
• Publication Number:
  US 20180217078A1
• Time in Patent Office: Days
• CPC Class Codes: G01N 17/04 Corrosion probes
• CPC Class Codes: G01N 27/223 for determining moisture content, e.g. humidity rain detectors on vehicle windows B60S1/0825

Abstract

An integrated electronic device, for detecting for detecting changes in an environmental parameter indicative of an environment surrounding the device, includes: a first conductive element and a second conductive element; a measurement circuit including a first measurement terminal and a second measurement terminal respectively coupled to the first conductive element and the second conductive element. The measurement circuit is configured to provide an electrical potential difference between the first conductive element and the second conductive element is configured to determine a change in an impedance of an electromagnetic circuit including the first conductive element and the second conductive element and formed between the first measurement terminal and the second measurement terminal. The device determines that an increase in a presence of water within the environment has occurred in response to a decrease in a real part of the impedance of the electromagnetic circuit.

Claims

1. A device for detecting changes in an environmental parameter indicative of an environment surrounding the device, the device comprising:

a first conductive element and a second conductive element;

a measurement circuit comprising a first measurement terminal and a second measurement terminal respectively coupled to the first conductive element and the second conductive element, the measurement circuit being configured to provide an electrical potential difference between the first conductive element and the second conductive element;

an insulating layer at least partially enclosing the first conductive element, the second conductive element, and the measurement circuit;

a first pad extending through the insulating layer and conductively coupled to the first conductive element;

a second pad extending through the insulating layer and conductively coupled to the second conductive element; and

an electrode assembly disposed over the insulating layer and conductively coupled to the first pad and the second pad and exposed to the environment, wherein;

the measurement circuit is configured to determine a change in an impedance of an electromagnetic circuit comprising the first conductive element and the second conductive element and formed between the first measurement terminal and the second measurement terminal;

the change in the impedance of the electromagnetic circuit is indicative of a change in the environmental parameter;

the impedance of the electromagnetic circuit is a complex number;

the device determines that an increase in a level of humidity of the environment has occurred in response to a decrease in an imaginary part of the impedance of the electromagnetic circuit;

the device determines that an increase in a presence of water within the environment has occurred in response to a decrease in a real part of the impedance of the electromagnetic circuit; and

the device determines that corrosion of a metal structure present within the environment has occurred in response to an increase in the real part of the impedance of the electromagnetic circuit.

2. The device of claim 1, wherein the insulating layer comprises a passivation and galvanic insulation material.

3. The device of claim 1, wherein the environment surrounding the device is solid material that includes metal structures.

4. The device of claim 3, wherein the solid material comprises concrete and the metal structures comprise metal rods within the concrete.

5. The device of claim 1, wherein the impedance of the electromagnetic circuit comprises an impedance of the electrode assembly exposed to the environment.

6. The device of claim 1, wherein the electrode assembly comprises a serpentine conductive stripe disposed on the insulating layer and connecting the first pad to the second pad.

7. The device of claim 6, wherein a first end of the serpentine conductive stripe physically contacts the first pad, and wherein a second end of the serpentine conductive stripe physically contacts the second pad.

8. The device of claim 6, wherein the impedance of the electromagnetic circuit comprises a capacitance between adjacent segments of the serpentine conductive stripe.

9. The device of claim 1, further comprising:

an equivalent electrode formed by water, humidity, or a combination thereof in the environment surrounding the device and in proximity to the insulating layer.

10. The device of claim 9, wherein the impedance of the electromagnetic circuit comprises an impedance of the equivalent electrode, a first equivalent capacitance formed between the equivalent electrode and the first conductive element, and a second equivalent capacitance formed between the equivalent electrode and the second conductive element.

11. The device of claim 10, wherein the impedance of the electromagnetic circuit comprises a series connection of the impedance of the equivalent electrode, the first equivalent capacitance, and the second equivalent capacitance.

12. The device of claim 9, further comprising:

an integrated antenna separated from the environment by the insulating layer and operatively coupled with the measurement circuit to wirelessly receive measurements and detections from the measurement circuit;

a support on the insulating layer and exposed to the environment; and

a second electromagnetic circuit integrated into the support and operatively coupled with the integrated antenna to wirelessly receive the measurements and detections from the integrated antenna, the second electromagnetic circuit being further configured to retransmit the measurements and detections.

13. The device of claim 1, further comprising:

an electrode assembly disposed over the insulating layer, wherein the electrode assembly comprises a pair of spaced apart third conductive members with a gap there between exposing the insulating layer, the pair of spaced apart third conductive members providing an equivalent external impedance when the gap is filled by water or humidity to form a first capacitor having a first capacitance with the first conductive element, and to form a second capacitor having a second capacitance with the second conductive element so that the electromagnetic circuit comprises the first capacitor, the pair of spaced apart third conductive members, the gap filled by the water or humidity, and the second capacitor coupled in series, and with the impedance of the electromagnetic circuit being defined by the first capacitance, the equivalent external impedance, and the second capacitance.

14. A method for detecting changes in an environmental parameter indicative of an environment, the method comprising:

placing a device in the environment, the device comprising;

a first conductive element and a second conductive element;

a measurement circuit comprising a first measurement terminal and a second measurement terminal respectively coupled to the first conductive element and the second conductive element, the measurement circuit being configured to provide an electrical potential difference between the first conductive element and the second conductive element;

an insulating layer at least partially enclosing the first conductive element, the second conductive element, and the measurement circuit;

a first pad extending through the insulating layer and conductively coupled to the first conductive element;

a second pad extending through the insulating layer and conductively coupled to the second conductive element; and

an electrode assembly disposed over the insulating layer and conductively coupled to the first pad and the second pad and exposed to the environment;

correlating a change in an impedance of an electromagnetic circuit with changes in the environmental parameter, the electromagnetic circuit comprising the first conductive element and the second conductive element and formed between the first measurement terminal and the second measurement terminal, the impedance of the electromagnetic circuit being a complex number, wherein correlating the change in the impedance of the electromagnetic circuit with changes in the environmental parameter comprises;

determining that an increase in a level of humidity of the environment has occurred in response to a decrease in an imaginary part of the impedance of the electromagnetic circuit;

determining than an increase in a presence of water within the environment has occurred in response to a decrease in a real part of the impedance of the electromagnetic circuit; and

determining than corrosion of a metal structure present within the environment has occurred in response to an increase in the real part of the impedance of the electromagnetic circuit, wherein the impedance of the electromagnetic circuit comprises an impedance of the electrode assembly exposed to the environment.

15. The method of claim 14, wherein the insulating layer comprises a passivation and galvanic insulation material.

16. The method of claim 14, wherein the environment surrounding the device is a solid material that includes metal structures.

17. The method of claim 16, wherein the solid material comprises concrete and the metal structures comprise metal rods within the concrete.