Angle measuring system

• US 6,995,836 B1
• Filed: 10/25/2000
• Issued: 02/07/2006
• Est. Priority Date: 11/26/1999
• Status: Expired due to Term

• Current Assignee: Dr. Johannes Heidenhain GmbH
• Original Assignee: Dr. Johannes Heidenhain GmbH
• Inventors: Holzapfel, Wolfgang, Seyfried, Volker, Braasch, Jan, Tondorf, Sebastian, Thiel, Jürgen
• Primary Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US10/148,111
• Time in Patent Office: 1,931 Days
• Field of Search: 356/3, 356138-147, 250/231.13, 250/231.14, 250/231.15, 250/231.16, 250/231.17, 250/231.18
• US Class Current: 356/138
• CPC Class Codes: G01D 5/26 characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
• CPC Class Codes: G01S 13/75 using transponders powered from received waves, e.g. using passive transponders , or using passive reflectors
• CPC Class Codes: G01S 3/782 Systems for determining direction or deviation from predetermined direction

Abstract

An angle measuring system for the contactless determination of an angle between a first object and a second object which can be moved with respect to each other, the angle measuring system including a first component having a light source and connected to a first object and a second component having a photodetector and connected to a second object. A grating is connected either to the first component or the second component, the grating having a combined amplitude-phase grating.

Claims

1. An angle measuring system for the contactless determination of an angle between a first object and a second object which can be moved with respect to each other, comprising:

a first component comprising a light source and connected to a first object;

a second component comprising a photodetector and connected to a second object;

a grating connected either to said first component or said second component, said grating comprises a combined amplitude-phase grating, wherein said grating has a sin²-shaped pattern of transmission intensity, and phase shifts of 180°

are present in zero points of said pattern of transmission intensity.

2. The angle measuring system in accordance with claim 1, wherein said grating comprises a transparent carrier material on which opaque layers of an amplitude graduation, as well as transparent layers of a phase graduation, are arranged.

3. The angle measuring system in accordance with claim 2, wherein said opaque layers define a series of spaces lying therebetween, and wherein each of said transparent layers are arranged in separate ones of said spaces and no two of said transparent layers are arranged in consecutive ones of said series of spaces so as to cause a phase shift of 180°

of light passing through.

4. The angle measuring system in accordance with claim 2, wherein phase strips of said phase graduation are arranged on a side of said grating between opaque strips of said amplitude graduation, which cause a phase shift of 180°

of light passing through.

5. The angle measuring system in accordance with claim 1, wherein said grating comprises a two-dimensional amplitude graduation, only defined places of which are transparent, wherein a phase graduation is alternatingly arranged respectively horizontally and vertically at said transparent places, which causes a phase deviation of 0°

or 180°

.

6. The angle measuring system in accordance with claim 1, wherein said photodetector is a structured photodetector, which includes a plurality of individual photo elements, which are arranged parallel with respect to an intensity strip pattern generated by said light source and said grating.

7. An angle measuring system for the contactless determination of an angle between a first object and a second object which can be moved with respect to each other, comprising:

a first component comprising a light source and connected to a first object;

a second component comprising a photodetector and connected to a second object;

a grating connected either to said first component or said second component, said grating comprises a combined amplitude-phase grating;

wherein said photodetector is a structured photodetector, which includes a plurality of individual photo elements, which are arranged parallel with respect to an intensity strip pattern generated by said light source and said grating.

8. The angle measuring system in accordance with claim 7, wherein said grating is assigned to said second component, and said grating is arranged at a fixed spatial relationship with said photodetector, and a distance between said light source and said grating is considerably greater than a distance between said grating and said photodetector.

9. The angle measuring system in accordance with claim 7, further comprising a controllable amplifier, which regulates power conducted to said light source as a function of an output detected in said photodetector.

10. The angle measuring system in accordance with claim 7, wherein said light source is structured so that for every possible location of said light source in relation to said photodetector an emission center of light beams emitted by said light source lies at the same location.

11. The angle measuring system in accordance with claim 10, wherein said light source is spherical.

12. The angle measuring system in accordance with claim 10, wherein said light source is flat, at least in sections.

13. The angle measuring system in accordance with claim 7, wherein said grating comprises a transparent carrier material on which opaque layers of an amplitude graduation, as well as transparent layers of a phase graduation, are arranged.

14. The angle measuring system in accordance with claim 13, wherein said opaque layers define a series of spaces lying therebetween, and wherein each of said transparent layers are arranged in separate ones of said spaces and no two of said transparent layers are arranged in consecutive ones of said series of spaces so as to cause a phase shift of 180°

of light passing through.

15. The angle measuring system in accordance with claim 13, wherein phase strips of said phase graduation are arranged on a side of said grating between opaque strips of said amplitude graduation, which cause a phase shift of 180°

of light passing through.

16. An angle measuring system for the contactless determination of an angle between a first object and a second object which can be moved with respect to each other, comprising;

a first component comprising a light source and connected to a first object;

a second component comprising a photodetector and connected to a second object;

a grating connected either to said first component or said second component, said grating comprises a combined amplitude-phase grating;

wherein said photodetector is a structured photodetector, which includes a plurality of individual photo elements, which are arranged parallel with respect to an intensity strip pattern generated by said light source and said grating; and

wherein, for a defined distance between said light source and said photodetector, at least an averaged period of said intensity strip pattern is a whole-number multiple of a period of structuring of said structured photodetector.

17. An angle measuring system for the contactless determination of an angle between a first object and a second object which can be moved with respect to each other, comprising:

a first component comprising a light source and a photodetector and connected to a first object;

a second component comprising a retro-reflecting element and connected to a second object;

a grating connected either to said first component or said second component, said grating comprises a combined amplitude-phase grating, wherein said grating has a sin²-shaped pattern of transmission intensity, and phase shifts of 180°

are present in zero points of said pattern of transmission intensity.

18. The angle measuring system in accordance with claim 17, wherein said grating comprises a transparent carrier material on which opaque layers of an amplitude graduation, as well as transparent layers of a phase graduation, are arranged.

19. The angle measuring system in accordance with claim 18, wherein said opaque layers define a series of spaces lying therebetween, and wherein each of said transparent layers are arranged in separate ones of said spaces and no two of said transparent layers are arranged in consecutive ones of said series of spaces so as to cause a phase shift of 180°

of light passing through.

20. The angle measuring system in accordance with claim 18, wherein phase strips of said phase graduation are arranged on a side of said grating between opaque strips of said amplitude graduation, which cause a phase shift of 180°

of light passing through.

21. The angle measuring system in accordance with claim 17, wherein said grating comprises a two-dimensional amplitude graduation, only defined places of which are transparent, wherein a phase graduation is alternatingly arranged respectively horizontally and vertically at said transparent places, which causes a phase deviation of 0°

or 180°

.

22. The angle measuring system in accordance with claim 17, wherein said photodetector is a structured photodetector, which includes a plurality of individual photo elements, which are arranged parallel with respect to an intensity strip pattern generated by said light source and said grating.

23. An angle measuring system for the contactless determination of an angle between a first object and a second object which can be moved with respect to each other, comprising:

a first component comprising a light source and a photodetector and connected to a first object;

a second component comprising a retro-reflecting element and connected to a second object;

a grating connected either to said first component or said second component, said grating comprises a combined amplitude-phase grating;

wherein said photodetector is a structured photodetector, which includes a plurality of individual photo elements, which are arranged parallel with respect to an intensity strip pattern generated by said light source and said grating.

24. The angle measuring system in accordance with claim 23, further comprising a controllable amplifier, which regulates power conducted to said light source as a function of an output detected in said photodetector.

25. The angle measuring system in accordance with claim 23, wherein said light source is structured so that for every possible location of said light source in relation to said photodetector an emission center of light beams emitted by said light source lies at the same location.

26. The angle measuring system in accordance with claim 25, wherein said light source is spherical.

27. The angle measuring system in accordance with claim 25, wherein said light source is flat, at least in sections.

28. The angle measuring system in accordance with claim 23, wherein said grating is assigned to said second component, and said grating is arranged at a fixed spatial relationship with said photodetector, and a distance between said light source and said grating is considerably greater than a distance between said grating and said photodetector.

29. The angle measuring system in accordance with claim 23, wherein said grating comprises a transparent carrier material on which opaque layers of an amplitude graduation, as well as transparent layers of a phase graduation, are arranged.

30. The angle measuring system in accordance with claim 29, wherein said opaque layers define a series of spaces lying therebetween, and wherein each of said transparent layers are arranged in separate ones of said spaces and no two of said transparent layers are arranged in consecutive ones of said series of spaces so as to cause a phase shift of 180°

of light passing through.

31. The angle measuring system in accordance with claim 29, wherein phase strips of said phase graduation are arranged on a side of said grating between opaque strips of said amplitude graduation, which cause a phase shift of 180°

of light passing through.

32. An angle measuring system for the contactless determination of an angle between a first object and a second object which can be moved with respect to each other, comprising:

a first component comprising a light source and a photodetector and connected to a first object;

a second component comprising a retro-reflecting element and connected to a second object;

a grating connected either to said first component or said second component, said grating comprises a combined amplitude-phase grating;

wherein said photodetector is a structured photodetector, which includes a plurality of individual photo elements, which are arranged parallel with respect to an intensity strip pattern generated by said light source and said grating; and

wherein, for a defined distance between said light source and said photodetector, at least an averaged period of said intensity strip pattern is a whole-number multiple of a period of structuring of said structured photodetector.