Optical sensor system

• US 5,572,315 A
• Filed: 11/14/1994
• Issued: 11/05/1996
• Est. Priority Date: 11/30/1993
• Status: Expired due to Term

• Current Assignee: Temic Telefunken Microelectronic GmbH (Continental AG)
• Original Assignee: Temic Telefunken Microelectronic GmbH (Continental AG)
• Inventors: Krell, Stephan
• Primary Examiner(s): Rosenberger, Richard A.
• Application Number:
  US08/339,720
• Time in Patent Office: 722 Days
• Field of Search: 356/136, 318/483, 318/444, 318/DIG. 2, 250/341.8
• US Class Current: 356/136
• CPC Class Codes: B60S 1/0818 including control systems responsive to external conditions, e.g. by detection of moisture, dirt or the like
• CPC Class Codes: B60S 1/0833 Optical rain sensor
• CPC Class Codes: G01N 21/43 by measuring critical angle
• CPC Class Codes: Y10S 318/02 Windshield wiper controls

Abstract

A sensor system for the measurement of the optical conditions at a boundary surface between a first medium that is a solid body and a second medium whose refracting indices are different. The sensor system has an optical unit comprising at least one sending unit with at least one sending element, at least one receiving unit with at least one receiving element, and an optical path connecting the send unit(s) to the receiving unit(s). A light-conducting body with a base surface and two optically active end surfaces is arranged in the optical path, where the base surface of the light-conducting body is attached to the surface side of the first medium between the sending unit(s) and the boundary surface. The first end surface of the light-conducting body is directed towards the sending unit(s) and the second end surface of the light-conducting body is directed towards the receiving unit(s). The two end surfaces of the light-conducting body, the light emission surface of the sending unit(s) and the light admission surface of the receiving unit(s) are made with a predetermined convex shape.

Claims

1. A sensor system for determining the optical conditions at a boundary surface which separates a first medium in the form of a solid body and a second medium whose refracting indices (n₁, n₂) are different from one another, with the sensor system having an optical unit which comprises:

at least one sending unit with at least one sending element and having a light emission surface;

at least one receiving unit with at least one receiving element, and having a light admission surface;

an optical path linking the sending unit with the at least receiving unit;

a light-conducting body arranged in the optical path and having a base surface and first and second optically active end surfaces, with the base surface of the light-conducting body being affixed to the surface side of the first medium disposed between the at least one sending unit and the at least one receiving unit and the boundary surface, and with the first end surface of the light-conducting body facing the light emission surface of the at least one sending unit and the second end surface of the light-conducting body facing the light admission surface of the receiving unit;

and wherein the first and second end surfaces of the light-conducting body, the light emission surface of the at least one sending unit, and the light admission surface of the at least one receiving unit are each provided with a predetermined convex shape, with the light emission surface of the sending unit and the light admission surface of the receiving unit each having such a weakly convex shape and with the two end surfaces of the light-conducting body each having such a strongly convex shape that the emitted radiation received on the base surface of the light-conducting body is distributed homogeneously and the distance (a₁) between the at least one sending unit and light-conducting body and the distance (a₂) between the at least one receiving unit and light-conducting body are minimal.

2. Sensor system in accordance with claim 1, wherein the light emission surface of the at least one sending unit and the light admission surface of the at least one receiving unit have the same weak convex shape.

3. Sensor system in accordance with claim 2, wherein the first and second end surfaces of the light-conducting body have the same strong convex shape.

4. Sensor system in accordance with claim 1, wherein the base surface of the light-conducting body is in a planar arrangement on surface side of the first medium such that there is no air gap between the base surface of the light conducting body and the one surface side of the first medium.

5. Sensor system in accordance with claim 1, wherein the light-conducting body is attached to the one surface side of the first medium by a transparent adhesive.