Device and method for the optical detection of objects

• US 20030227635A1
• Filed: 05/15/2003
• Published: 12/11/2003
• Est. Priority Date: 05/17/2002
• Status: Active Grant

• Current Assignee: Baumer Electric AG (Baumer Holding AG)
• Original Assignee: Hera Rotterdam B.V.
• Inventors: Muller, Klaus
• Granted Patent: US 7,046,378 B2
• Time in Patent Office: Days
• US Class Current: 356/614
• CPC Class Codes: G01B 11/026 by measuring distance between sensor and object G01B11/0608 takes precedence
• CPC Class Codes: G01C 3/085 with electronic parallax measurement

Abstract

A method and a device for the optical distance measurement or for the optical detection of objects with an at least partially specular reflective surface (12) are based on the fact, that light through the specular reflective surface (12) and a diffuse scattering at a reflector (4) is directed to light receiving means and detected there.

Claims

1. Method for the optical distance measurement or for the optical detection of objects with an at least partially reflective surface (12), wherein through the reflective surface (12) and a diffuse scattering on a reflector (4) light is directed to light receiving means and detected there.

2. Method in accordance with claim 1, characterised in that light scattered by the reflector (4) is reflected by the reflective surface (12) in such a manner that it is directed to the light receiving means.

3. Method according to claim 2, characterised in that a light beam (11) is reflected by the reflective surface in such a manner that it impinges on the reflector (4) and that light of the light beam scattered by the reflector (4) is reflected to the receiving lens system by the reflective surface (12).

4. Device for the optical distance measurement or for the optical detection of objects with an at least partially reflective surface (12), comprising a light source (2) for the generation of a light beam (11), light receiving means and evaluation means for the evaluation of light signals received through the light receiving means, characterised by an at least partially diffusely scattering reflector (4), wherein light is capable of being directed from the light source (2) through the reflector (4) and the surface (12) to the light receiving means.

5. Device in accordance with claim 4, characterised in that the light source (2) and the reflector (4) are arranged in such a manner, that during operation of the device a light beam (11) produced by the light source (2) impinges on the reflective surface (12) with an angle of incidence of less than 45 degrees to a direction normal to the reflective plane (12).

6. Device according to claim 4, characterised in that the light source (2) and the reflector (4) are arranged in such a manner, that during operation of the device a light beam (11) produced by the light source (2) impinges on the reflective surface (12) with an angle of incidence of more than 30 degrees to a direction normal to the reflective surface (12).

7. Device in accordance with one of the claims 4 to 6, characterised in that it comprises a holder or guide for the arrangement of an object with an at least partially reflective surface (12) in a position defined with respect to the light source (2) and the reflector (4).

8. Device according to one of the claims 4 to 7, characterised in that it comprises means for the evaluation of the angles of incidence of two light beams (10, 15) and for the determination of corresponding distance values.

9. Device in accordance with one of the claims 4 to 8, characterised in that the light source, the light receiving means and the reflector are integrated in a sensor.

10. Utilisation of the device according to one of the claims 4 to 9 for the detection of the position of a silicon wafer surface.