Sensor unit for detecting the wetting of a window

• US 20030080871A1
• Filed: 10/28/2002
• Published: 05/01/2003
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Preh-Werke GmbH & Company KG
• Original Assignee: Preh-Werke GmbH & Company KG
• Inventors: Hartmann, Rudolf, Schmitt, Hans-Michael, Polzer, Thomas, Bach, Juergen
• Granted Patent: US 6,888,465 B2
• Time in Patent Office: Days
• US Class Current: 340/604
• CPC Class Codes: B60H 1/00785 by the detection of humidity or frost
• CPC Class Codes: B60S 1/0822 characterized by the arrangement or type of detection means
• CPC Class Codes: B60S 1/0825 Capacitive rain sensor
• CPC Class Codes: G01N 27/226 Construction of measuring vessels; Electrodes therefor

Abstract

The invention relates to a sensor unit for detecting the wetting of a window. Signals from the condensation sensor are used to control an air conditioning, heating, and/or ventilation unit. The signals of the rain sensor, on the contrary, are used to control a windshield wiper or washing unit for vehicles. A sensor unit, which comprises two sensors, is placed on the interior of the window. In a preferred variant, both are coupled to a common switchable evaluation unit, so that through mutual evaluation of the two sensors or their signals, both incipient condensation on the interior of a vehicle window and the wetting of the exterior, e.g., by rain, is detected. In an improvement of the invention, both sensors are integrated into a sensor module.

Claims

1. A sensor unit for detecting the wetting of a window, comprising:

a first sensor for detecting internal wetting, the first sensor being located on the interior of the window; and

a second sensor for detecting external wetting, and is placed on the interior of the window.

2. The sensor unit according to claim 1, wherein said first and second sensors are electrically connected to a common switchable evaluation unit, and wherein the sensor signal is connected to the evaluation unit whose signal is to be evaluated by the evaluation unit.

3. The sensor unit according to claim 1, wherein the sensor unit is constructed as a sensor module.

4. The sensor unit according to claim 3, wherein said first and second sensors are placed together on a supporting component of the sensor module.

5. The sensor unit according to claim 3, wherein components of at least one evaluation unit are located on a supporting component of the sensor module.

6. The sensor unit according to claim 1, wherein the internal wetting of the first sensor is detected by the direct capacitative measuring principle, and the external wetting of the second sensor is detected by the direct capacitative measuring principle.

7. The sensor unit according to claim 6, wherein the first sensor has a polymeric gold film.

8. The sensor unit according to claim 6, wherein the first sensor has an interdigital structure.

9. The sensor unit according to claim 6, wherein the second sensor has a capacitative electrode structure in a nondifferential arrangement of the sensor surfaces.

10. The sensor unit according to claim 1, wherein the first sensor is a condensation sensor, and the second sensor is a rain sensor.

11. A method for detecting interior and exterior wetting of a window, said method comprising the following steps:

detecting interior wetting of the window by a first sensor positioned on an interior surface of the window; and

detecting, almost simultaneously, exterior wetting of the window by a second sensor positioned on the interior surface of the window,

whereby an evaluation unit receives signals from said first sensor and said second sensor, makes an evaluation and outputs an output, dependent on the evaluation.