Moisture ingress sensors

Patent metadata

Field	Value
Publication number	US-9752999-B2
Application number	US-201414290866-A
Country	US
Kind code	B2
Filing date	May 29, 2014
Priority date	May 29, 2014
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

This application relates to a moisture ingress sensor. In particular, this application relates to a moisture ingress sensor that can detect liquid ingress into an electronic device. The moisture ingress sensor can include a resistor, an N-channel MOSFET, an operation amplifier, comparators, and an AND logic gate. The moisture ingress sensor is configured to provide a lower power means for accurately detecting moisture in an electronic device. Multiple areas of the electronic device can include the moisture ingress sensor in order to optimize the detection of moisture for at a variety of regions of the electronic device. Additionally, the electronic device can record signals from the moisture ingress sensor and shut down components of the electronic device that could be affected by the detected moisture. Furthermore, the moisture ingress sensor can be tuned to detect one or more types of liquids.

First claim

What is claimed is:

1. A moisture sensor capable of detecting multiple moisture events, comprising:
a moisture interface element capable of providing an electrical parameter value associated with a moisture detection event, wherein a first moisture event comprises: the moisture interface element providing a first electrical parameter value having a first peak value that is less than a threshold value such that the moisture interface element is prevented from issuing an activation signal, and wherein, a second moisture event subsequent to the first moisture event comprises: the moisture interface element remaining operable to provide a second electrical parameter value having a second peak value that includes at least the first peak value such that when the second peak value is greater than the threshold value, the moisture interface element provides the activation signal;
a logic circuitry connected to the moisture interface element; and
a signal processing portion connected to the logic circuitry and the moisture interface element, wherein the signal processing portion is arranged to (i) receive the activation signal, and (ii) send a corresponding reference signal to the logic circuitry such that the logic circuitry uses the corresponding reference signal to provide a moisture indication signal that corresponds to the first or the second moisture event.

2. The moisture sensor of claim 1 , wherein the moisture interface element is a passive component comprising a first node and a second node coupled to a bias voltage.

3. The moisture sensor of claim 1 , further comprising:
a bias switch connected to the moisture interface element, wherein the bias switch is configured to allow the activation signal to pass through.

4. The moisture sensor of claim 3 , wherein the bias switch opens in response to receiving the activation signal.

5. The moisture sensor of claim 1 , wherein an electrical resistance of the moisture interface element is increased upon the detection of any of the first or second moisture events.

6. The moisture sensor of claim 1 , wherein the logic circuitry comprises:
at least two comparators connected to the moisture interface element, and an AND gate connected to the at least two comparators, wherein the at least two comparators define a tolerance that determines when the AND gate will cause the logic circuitry to output the moisture indication signal.

7. The moisture sensor of claim 1 , wherein the signal processing portion includes an insulated gate device.

8. The moisture sensor of claim 7 , wherein the signal processing portion includes an operational amplifier, and the insulated gate device is biased to a reference voltage of the operational amplifier.

9. The moisture sensor of claim 1 , wherein the threshold value is a peak resistance.

10. A moisture ingress sensor for minimizing damage to an electronic component of a device, comprising:
a moisture interface element having an electrical resistance that is adjusted upon exposure of the moisture interface element to a first moisture event such that: (i) when a result of a detection of the first moisture event exceeds a threshold, then issuing a first activation signal, otherwise (ii) when the result of the detection of the first moisture event is less than the threshold: adjusting the electrical resistance upon the exposure of the moisture interface element to a second moisture event, and issuing a second activation signal upon determining that the second moisture event exceeds the threshold;
a bias switch that is configured to open in response to receiving any of the first or second activation signals from the moisture interface element;
a logical component coupled to the moisture interface element; and
a signal processing portion connected to the moisture interface element, wherein the signal processing portion is capable of (i) receiving any of the first or second activation signals, and (ii) sending a corresponding reference signal to the logical component, thereby causing the logical component to utilize the corresponding reference signal to provide a moisture indication signal.

11. The moisture ingress sensor of claim 10 , wherein the moisture interface element is a passive element that decreases in electrical resistance when the first or second moisture events exceed the threshold.

12. The moisture ingress sensor of claim 10 , further comprising:
at least two comparators, wherein the at least two comparators define a high tolerance and a low tolerance.

13. The moisture ingress sensor of claim 12 , wherein the signal processing portion includes an insulated gate device.

14. The moisture ingress sensor of claim 13 , wherein the signal processing portion includes an operational amplifier, and the insulated gate device is biased to a reference voltage of the operational amplifier.

15. A method for detecting multiple moisture events by a moisture ingress sensor of a computing device, the moisture ingress sensor including a moisture interface element capable of providing an electrical parameter value associated with a detection of a moisture event, the method comprising:
when the moisture interface element detects a first moisture event:
providing a first electrical parameter value having a first peak value that is less than a threshold value such that the moisture interface element is prevented from issuing an activation signal to a logic component of the moisture ingress sensor;

when the moisture interface element detects a second moisture event subsequent to the first moisture event, the second moisture event causes the moisture interface element to provide a second electrical parameter value having a second peak value that includes at least the first peak value:
providing the activation signal to the logic component when the second peak value satisfies the threshold value,
causing the logic component to send a moisture indication signal, and
sending a switch signal to a bias switch that opens the bias switch of the moisture ingress sensor.

16. The method of claim 15 , further comprising:
preventing further operation of an electronic component of the computing device when the second peak value of the second moisture event satisfies the threshold value.

17. The method of claim 15 , wherein the activation signal is transmitted to a metal oxide semiconductor field effect transistor (MOSFET) and a reference voltage is transmitted to the logic component when the second peak value of the second moisture event satisfies the threshold value.

18. The method of claim 17 , further comprising:
causing comparators to allow a reference voltage to proceed to the logic component when the reference voltage is within a predetermined tolerance of the comparators.

19. The method of claim 15 , wherein the threshold value corresponds to a predetermined peak resistance value.

20. The method of claim 15 , wherein an electrical resistance of the moisture interface element is increased upon the detection of any of the first or second moisture events.

Assignees

• Apple Inc

Inventors

• Kalinichev Kirill
• Keeler Kevin M
• Menzel Brian C

Classifications

• G01N27/048 Primary

  for determining moisture content of the material · CPC title

• H02H5/083 Primary

  responsive to the entry or leakage of a liquid into an electrical appliance (moisture alarm G08B21/20) · CPC title

• G01N27/121

  for determining moisture content, e.g. humidity, of the fluid (moisture content of the tested material G01N27/048) · CPC title