Optical sensor

• US 6,668,104 B1
• Filed: 07/24/2000
• Issued: 12/23/2003
• Est. Priority Date: 09/15/1998
• Status: Expired due to Fees

• Current Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Original Assignee: Robert Bosch GmbH
• Inventors: Mueller, Lutz, Bernhard, Winfried, Mueller, Andre, Schink, Rainer, Mueller-Fiedler, Roland, Sautter, Helmut
• Primary Examiner(s): Bovernick, Rodney
• Assistant Examiner(s): PAK, SUNG H
• Application Number:
  US09/554,347
• Time in Patent Office: 1,247 Days
• Field of Search: 385/12, 385/31, 385/15
• US Class Current: 385/12
• CPC Class Codes: B60S 1/0822 characterized by the arrangement or type of detection means
• CPC Class Codes: B60S 1/0837 with a particular arrangement of the optical elements
• CPC Class Codes: B60S 1/0881 characterized by the attachment means on the windshield
• CPC Class Codes: B60S 1/0888 characterized by the attachment of the elements in a unit
• CPC Class Codes: G01D 5/268 using optical fibres G01D5/28 - G01D5/38 take precedence
• CPC Class Codes: G01N 21/552 Attenuated total reflection

Abstract

An optical sensor for detecting wetting of a surface (11), In particular of a vehicle window, has at least one transmitter (13) and at least one receiver (15) for electromagnetic waves, the surface being located in a sensor region (16) between the at least one transmitter (13) and the at least one receiver (15). The development of wetting on the sensor region (16) of the surface (11) causes a signal change. The optical sensor has a light-carrying element (18), in which the electromagnetic waves are guided bidirectionally into the sensor region (16) and out of the sensor region (16), and a retroreflector (10) is disposed in the sensor region (16) in such a way that it returns the electromagnetic waves, reflected before the surface (11), back to the surface (11) and from there to the light-carrying element (18).

Claims

1. An optical sensor for detecting wetting of a surface (11), in particular of a vehicle window, comprising at least one transmitter (13) and at least one receiver (15) for electromagnetic waves, the surface being located in a sensor region (16) between the at least one transmitter (13) and the at least one receiver (15), wherein the development of wetting on the sensor region (16) of the surface (11) causes a signal change, wherein the optical sensor has a light-carrying element (18), in which the electromagnetic waves are guided bidirectionally into the sensor region (16) and out of the sensor region (16) in such a way that it returns the electromagnetic waves, reflected from the surface (11), back to the surface (11) and from there to the light-carrying element (18), wherein the light-carrying element (18) is a monomode or multimode optical waveguide, wherein a retroreflector (10) is provided and formed of a hologram (38) in the form of a plate or film, and wherein the disposition of the reflective segments of the retroreflector (10) is circular or striplike.

2. The optical sensor of claim 1, wherein the light-carrying element (18) is an optical waveguide comprising glass or plastic.

3. The optical sensor of claim 1, wherein the light-carrying element (18) is an optical waveguide comprising glass or plastic.

4. The optical sensor of claim 1, wherein the light-carrying element (18) is a plate or other suitably shaped body that can carry the light.

5. The optical sensor of claim 1, wherein the light-carrying element (18) has separate optical waveguides for the delivery and return of the electromagnetic waves.

6. The optical sensor of claim 1, wherein the light-carrying element (18) has a coupling element (20), by means of which a deflection of the electromagnetic waves onto the sensor region (16) is effected.

7. The optical sensor of claim 6, wherein the coupling element (20) is formed of an elbow (26) or prism (28) or by structuring (30) of the surface of the light-carrying element.

8. The optical sensor of claim 1, wherein a sensor-active substance (24) that in the presence of a measurement substance changes its coefficient of refraction or color is applied in the sensor region (16).

9. The optical sensor of claim 1 wherein the coupling element (20) and the light-carrying element (18) form a structural unit.

10. The optical sensor of claim 8, the retroreflector (10) and a substrate (22) of the measurement substance (24) form a structural unit.

11. The use of an optical sensor of claim 1, as a rain sensor in motor vehicles.

12. The use of an optical sensor of claim 8 as a sensor for various substances that are in the form of liquid, aerosol, or in solution or in gaseous form.

13. The optical sensor of claim 1, wherein the retroreflector (10) is disposed inside a windshield (12).

14. The optical sensor of claim 1, wherein the hologram is disposed inside a windshield (12).

15. The optical sensor of claim 14, wherein an adhesive film (40) disposed in the windshield (12) is itself at least partly embodied as a hologram (38).