Sensor for detecting condensation and use in a sensor module

• US 6,809,530 B2
• Filed: 10/28/2002
• Issued: 10/26/2004
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Preh-Werke GmbH & Company KG
• Original Assignee: Preh-Werke GmbH & Company KG
• Inventors: Oennig, Guenther, Hartmann, Rudolf, Blaufuss, Martin, Schmitt, Hans-Michael, Polzer, Thomas, Bach, Juergen
• Primary Examiner(s): Nolan, Jr., Charles H.
• Application Number:
  US10/281,360
• Publication Number:
  US 20030086475A1
• Time in Patent Office: 729 Days
• Field of Search: 324/689, 374/208
• US Class Current: 324/689
• CPC Class Codes: B60H 1/00785 by the detection of humidity or frost
• CPC Class Codes: B60S 1/0825 Capacitive rain sensor
• CPC Class Codes: B60S 1/0866 including a temperature sensor heating devices for windshield B60H

Abstract

As is well known, the influencing variables most important for a sense of comfort are considered during regulation in controlled heating and air conditioning units. Incipient condensation on the windshield or other windows in particular is to be prevented thereby. Sensor modules, inter alia, are employed for this purpose, which have, for example, a capacitative thin-layer sensor. An additional thermopile is provided for determining the window temperature. The present idea eliminates the determination of the window temperature, for which purpose a sensor working capacitatively in the exemplary embodiment is brought directly to the window temperature and a direct thermal coupling of the sensor with the window occurs via a metal plate connected directly to the sensor and a thin adhesive film. The metal plate can thereby form one of the electrodes of the sensor itself or be connected to said electrode in a direct thermal manner. The use of the sensor in the sensor module is a further preferred embodiment.

Claims

1. A sensor for detecting condensation on a window, the sensor directly attaining a temperature of the window such that a direct thermal coupling of the sensor with the window occurs so that a temperature of the sensor is substantially equal to a temperature of the window,

wherein condensation on the window is detected on the basis of a chance in capacitance in the sensor.

2. The sensor according to claim 1, wherein the direct thermal coupling occurs via a metal plate, which forms a bottom of the sensor, and wherein a lower surface of the metal plate is flush with the window.

3. The sensor according to claim 1, wherein a metal plate, which is provided in the sensor for the direct thermal coupling, is fixed onto the window by an adhesive with a high thermal conductivity.

4. The sensor according to claim 1, further comprising two electrodes, and a conductive, moisture-sensitive material disposed between the two electrodes, wherein the direct coupling with the window occurs via one of the electrodes and an adhesive with high thermal conductivity.

5. The sensor according to claim 4, wherein the direct thermal coupling of the sensor with the window occurs via a metal plate, which is connected to one of the two electrodes in a direct thermal manner.

6. The sensor according to claim 4, wherein the metal plate or one of the two electrodes is held in a plastic frame.

7. The sensor according to claim 4, wherein the moisture-sensitive material is a polymer.

15. The sensor according to claim 1, wherein the window is a vehicle window.

16. The sensor according to claim 3, wherein the adhesive is a thin film or glue.

8. A sensor module for detecting condensation on a window, said sensor module including a sensor that directly attains a temperature of the window such that a direct thermal coupling occurs so that a temperature of the sensor is substantially equal to a temperature of the window,

wherein condensation on the window is detected on the basis of a change in capacitance in the sensor.

9. The sensor module according to claim 8, wherein evaluation electronics are integrated into the module.

10. The sensor module according to claim 8, wherein the module is surrounded by a housing, and wherein an electrode of the sensor or a metal plate is held by the housing of the module with ends of the metal plate being flush with the housing.

11. The sensor module according to claim 10, wherein the electrode or the metal plate is held by a plastic frame of the housing.

12. The sensor module according to claim 8, wherein a temperature sensor can be integrated into the module.

13. The sensor module according to claim 8, wherein the module is built on a small scale and has the dimensions of being approximately 30 mm wide by 2.0 mm high by 4 mm deep.

14. The sensor module according to claim 8, wherein the sensor module can be preferably integrated in or on a base of an interior mirror.

17. The sensor module according to claim 14, wherein the sensor module is positioned between the window and the base of the interior mirror.

18. A sensor comprising:

a first electrode;

a second electrode; and

a conductive moisture-sensitive material being provided between the first electrode and the second electrode,

wherein the sensor is in direct thermal coupling with a window,

wherein a temperature of the sensor is substantially equal to a temperature of the window during a sensing operation, and

wherein moisture is detected on the window on the basis of a change in capacitance between the first electrode and the second electrode.

19. The sensor according to claim 18, wherein the second electrode is fixed to the window in order to provide the sensor with the direct thermal coupling to the window.

20. The sensor according to claim 18, wherein the sensor further comprises a metal plate that is fixed to the window for promoting thermal transfer from the window to the sensor.

21. The sensor according to claim 20, wherein the metal plate is thermally connected with the second electrode.

22. The sensor according to claim 18, wherein the sensor is affixed to the window via an adhesive.

23. The sensor according to claim 22, wherein the adhesive promotes thermal conductivity.

24. A method for detecting condensation on a window, the method comprising the steps of:

providing a sensor directly to the window so that the sensor is in direct thermal coupling with the window so that a temperature of the sensor is substantially equal to a temperature of the window, the sensor having a conductive moisture-sensitive material provided between a first and second electrode;

determining a change in capacitance between the first electrode and the second electrode; and

detecting moisture on the window on the basis of the change in capacitance between the first electrode and the second electrode.