Capacitive sensor for detecting surface condensation

• US 6,614,241 B2
• Filed: 03/28/2001
• Issued: 09/02/2003
• Est. Priority Date: 03/28/2000
• Status: Expired due to Fees

• Current Assignee: Preh-Werke GmbH & Company KG
• Original Assignee: Preh-Werke GmbH & Company KG
• Inventors: Bach, Juergen, Berthold, Gottfried, Schmitt, Hans-Michael
• Primary Examiner(s): Oda, Christine K.
• Application Number:
  US09/818,779
• Publication Number:
  US 20010030545A1
• Time in Patent Office: 888 Days
• Field of Search: 324/664, 340/604, 430/309
• US Class Current: 324/664
• CPC Class Codes: G01N 27/223 for determining moisture content, e.g. humidity rain detectors on vehicle windows B60S1/0825
• CPC Class Codes: G01N 27/226 Construction of measuring vessels; Electrodes therefor

Abstract

A capacitive sensor for detecting surface condensation which includes a carrier (2), a metal layer (3) applied to the carrier (2) to form an interdigital structure, a passivation layer (6) formed over the metal layer (3), and a hydrophilic layer (7) applied over the passivation layer (6), where the hydrophilic layer (7) increases a surface tension of the passivation layer (7).

Claims

1. A capacitive sensor for detecting surface condensation, comprising:

a carrier;

a metal layer applied to the carrier to form an interdigital structure;

a passivation layer formed over the metal layer; and

a hydrophilic layer being applied over the passivation layer through dipping or spraying, wherein the hydrophilic layer increases a surface tension of the passivation layer such that a uniform water film formation is achieved.

2. The sensor according to claim 1, wherein the passivation layer is an overglaze layer.

3. The sensor according to claim 1, wherein the hydrophilic layer has a thickness of 0.01 μ

m.

4. The sensor according to claim 1, wherein the hydrophilic layer promotes wetting.

5. The sensor according to claim 1, wherein the hydrophilic layer is a plied by way of spraying.

6. The sensor according to claim 1, wherein the hydrophilic layer is a plied by way of dipping.

7. A capacitive sensor, comprising:

a carrier member;

a first layer formed over the carrier member; and

a hydrophilic layer applied being over the first layer through dipping or spraying, the hydrophilic layer increasing a surface tension of the first layer such that a uniform water film formation is achieved.

8. The sensor according to claim 7, further comprising a metal layer formed over the carrier member.

9. The sensor according to claim 8, wherein the metal layer is applied directly to the carrier member.

10. The sensor according to claim 7, wherein the first layer is a passivation layer.

11. The sensor according to claim 10, wherein the passivation layer is an overglaze layer.

12. The sensor according to claim 7, further comprising an intermediate layer formed between the carrier member and the first layer, the intermediate layer being applied directly to the carrier and the first layer being directly applied directly to the intermediate layer.

13. The sensor according to claim 7, wherein the hydrophilic layer is applied directly to the first layer.

14. A method for providing a manufacturing a capacitive sensor, comprising the steps of:

(a) providing a carrier member;

(b) forming a metal layer over the carrier member;

(c) forming a passivation layer over the carrier member; and

(d) forming a hydrophilic layer over the passivation layer through dipping or spraying, wherein the hydrophilic layer increases a surface tension of the passivation layer such that a uniform water film formation is achieved.

15. The method according to claim 14, wherein step (b) forms the metal layer over and directly on the carrier member.

16. The method according to claim 14, wherein step (c) forms the passivation layer over and directly on the metal layer.

17. The method according to claim 14, wherein step (d) forms the hydrophilic layer directly on the passivation layer.

18. A capacitive sensor for detecting surface condensation, comprising:

a carrier having a metal layer applied to the carrier to form an interdigital structure, which forms the capacitor for the sensor; and

a passivation layer formed over the metal layer,

wherein a hydrophilic layer is applied over the passivation layer through dipping or spraying, through which a surface tension of the passivation layer is increased.