Method and system for automatic non-contact measurements of optical properties of optical objects

• US 6,496,253 B1
• Filed: 06/06/2000
• Issued: 12/17/2002
• Est. Priority Date: 06/14/1999
• Status: Expired due to Fees

• Current Assignee: Prolaser Limited
• Original Assignee: Prolaser Limited
• Inventors: Vokhmin, Peter A.
• Primary Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US09/588,067
• Time in Patent Office: 924 Days
• Field of Search: 356/124-127
• US Class Current: 356/124
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G01M 11/0264 by using targets or reference patterns

Abstract

Automatic non-contact measuring optical properties of an optical object is performed by a system comprising a light source, a reference pattern, and an imaging and detecting means and an image processing means for producing a measurement output. At least the reference pattern and the imaging and detecting means are disposed on an optical axis of the system. The system further comprises a support for the optical object located between the reference pattern and the imaging and detecting means for disposing thereon the optical object coaxially with the pattern and the imaging and detecting means. The light source is capable of directing to the pattern an illuminating light in such a manner as to produce a plurality of illuminating light beams outcoming from each point of the pattern at different angles. The imaging and detecting means is capable of obtaining an image of the pattern through the optical objects so that each imaging beam is conjugate with only one of the illuminating beams, and of recording the image for its processing by the image processing means.

Claims

1. A method for automatic non-contact measuring optical properties of an optical object by means of a system comprising a light source, a reference pattern, an imaging and detecting means, at least the reference pattern and the imaging and detecting means being disposed on an optical axis on the system, and an image processing means, said method comprising the steps of:

(a) disposing said optical object between said reference pattern and said imaging and detecting means coaxially therewith;

(b) directing to said pattern an illuminating light from said light source in such a manner as to produce a plurality of illuminating light beams outcoming from each point of the pattern at different angles;

(c) imaging said pattern through said optical object by means of imaging beams such that only one of said plurality of the illuminating beams has a conjugated imaging beam, and detecting the image, by said imaging and detecting means, and

(d) processing said image by said image processing means and producing a measurement output.

2. A method according to claim 1, wherein steps (b) and (c) are performed with the reference pattern being disposed by step (a) at two different positions and step (d) is performed based on two images obtained thereby.

3. A method according to claim 1, wherein step (b) is performed by said light source being a diffusive illuminator.

4. A method according to claim 1, wherein step (b) is performed by forming said reference pattern on a diffusive plate.

5. A method according to claim 1, wherein in step (c) said imaging and detecting means include a camera lens with an entrance pupil allowing only a minority of light beams that outcome from the optical object and correspond to different points of said reference pattern, to pass through said entrance pupil.

6. A method according to claim 5, wherein said imaging and detecting means direct to the entrance pupil only those light beams that outcome from the optical object substantially parallel to each other, said light beams being conjugate with the illuminating beams outcoming from different points of the reference pattern.

7. A method according to claim 1, wherein step (d) is performed by comparing the image with an image of said pattern obtained by said imaging and detecting means in the absence of said optical object.

8. A method according to claim 1, adapted for measuring a spherical optical power of said object at any predetermined point.

9. A method according to claim 1, adapted for measuring a cylindrical optical power and cylinder axis of said object at any predetermined point.

10. A method according to claim 1, adapted for measuring a prismatic optical power and a prism axis of said object at any predetermined point.

11. A method according to claim 1, adapted for measuring a location of an optical center of said optical object.

15. A system according to claim 7, wherein said imaging and detecting means include a camera with a camera lens having a pin-hole entrance pupil.

16. A system according to claim 15, wherein said imaging and detecting means include focusing optics for directing a part of light beams that outcome from the optical object to said entrance pupil, said light beams being conjugate with the illuminating beams outcoming from different points of said reference pattern.

17. A system according to claim 16, wherein said focusing optics directs to said entrance pupil those of the light beams conjugate with the illuminating beams outcoming from different point of said reference pattern, that outcome from the optical object substantially parallel to each other.

12. A system for automatic non-contact measuring optical properties of an optical object, comprising a light source, a reference pattern, an imaging and detecting means, at least the reference pattern and the imaging and detecting means being disposed on an optical axis of the system, a support for the optical object located between said reference pattern and said imaging and detecting means for disposing thereon the optical object coaxially with said pattern and said imaging and detecting means, said light source being capable of directing to said pattern an illuminating light in such a manner as to produce a plurality of illuminating light beams outcoming from each point of the pattern at different angles, said imaging and detecting means being capable of obtaining an image of said pattern through said optical object so that only one of said plurality of the illuminating beam has a conjugated imaging beam, and of recording said image, and an image processing means for processing said image and producing a measurement output.

13. A system according to claim 12, wherein said light source is a diffusive illuminator.

14. A system according to claim 12, wherein said reference pattern is formed on a diffusive plate.

18. A system according to claim 12, further comprising means for moving said reference pattern into at least two positions, and said image processing means being capable of providing said measurement output based on images of the reference pattern taken in the two positions thereof.

19. A system according to claim 12, wherein said measurement output is a spherical optical power of said object at any predetermined point.

20. A system according to claim 12, wherein said measurement output is a cylindrical optical power and cylinder axis of said object at any predetermined point.

21. A system according to claim 12, wherein said measurement output is a prismatic optical power and a prism axis of said object at any predetermined point.

22. A system according to claim 12, wherein said measurement output indicates to the location of said optical object'"'"'s optical center.

23. A system according to claim 12, wherein said measurement output is a spherical optical power map.

24. A system according to claim 12, wherein said measurement output is a cylindrical optical power map and a vector field of the cylinder axes.

25. A system according to claim 12, wherein said measurement output is a prismatic optical power map, a vector field of the prism axes and an optical center of the optical object.

26. A system according to claim 12, wherein said measurement output is a topographical map.