Wavefront sensor

• US 8,619,405 B2
• Filed: 10/29/2008
• Issued: 12/31/2013
• Est. Priority Date: 10/31/2007
• Status: Active Grant

• Current Assignee: Alcon Incorporated
• Original Assignee: WaveTec Vision Systems, Inc. (Alcon Incorporated)
• Inventors: Van Heugten, Anthony Y.
• Primary Examiner(s): DANG, HUNG XUAN
• Application Number:
  US12/740,753
• Publication Number:
  US 20110001960A1
• Time in Patent Office: 1,889 Days
• Field of Search: 351/221, 351/205, 351/206, 351209-213, 351/216, 351/246
• US Class Current: 361/221
• CPC Class Codes: A61B 3/1015 for wavefront analysis
• CPC Class Codes: G01J 2009/002 Wavefront phase distribution
• CPC Class Codes: G01J 9/00 Measuring optical phase difference devices or arrangements for controlling the phase of light beams G02F1/01; Determining degree of coherence; Measuring optical wavelength spectrometry G01J3/00
• CPC Class Codes: G01M 11/0264 by using targets or reference patterns

Abstract

The present invention relates to a wavefront sensor using a pair of screens, each having a two-dimensional array of circular apertures, to achieve Moiré effects, and its use to measure the slope of a wavefront.

Claims

1. An apparatus comprising:

a) a first screen comprising a first two-dimensional array of circular apertures, wherein the first screen is placed downstream of a light source;

b) a second screen comprising a second two-dimensional array of circular apertures, wherein the second screen is placed downstream of the first screen, the second screen is in a plane parallel to the first screen, and the second screen is rotated relative to the first screen; and

c) a light detector downstream of the second screen.

2. The apparatus of claim 1, wherein the first two-dimensional array and the second two-dimensional array are identical.

3. The apparatus of claim 1, wherein at least one screen is a Hartmann screen.

4. The apparatus of claim 3, wherein the first screen and the second screen are Hartmann screens.

5. The apparatus of claim 1, wherein at least one screen is a Shack-Hartmann lenslet array.

6. The apparatus of claim 5, wherein the first screen and the second screen are Shack-Hartmann lenslet arrays.

7. The apparatus of claim 1, wherein the second screen is rotated about 1to about 30 degrees relative to the first screen.

8. The apparatus of claim 1, further comprising a lens.

9. The apparatus of claim 8, wherein the lens is placed between the second screen and the light detector.

10. The apparatus of claim 8, wherein the lens is placed upstream of the first screen.

11. The apparatus of claim 1, further comprising a beam splitter positioned upstream of the first screen.

12. A method of measuring characteristics of a lens comprising:

a) directing light into the lens;

b) directing the light from the lens through a first screen comprising a first two-dimensional array of circular apertures;

c) directing the light from the first screen through a second screen comprising a second two-dimensional array of circular apertures, wherein the second screen is placed downstream of the first screen, the second screen is in a plane parallel to the first screen, and the second screen is rotated relative to the first screen;

d) detecting the light from the second screen at a light detector.

13. The method of claim 12, wherein the first two-dimensional array and the second two-dimensional array are identical.

14. The method of claim 12, wherein at least one screen is a Hartmann screen.

15. The method of claim 14, wherein the first screen and the second screen are Hartmann screens.

16. The method of claim 12, wherein at least one screen is a Shack-Hartmann lenslet array.

17. The method of claim 16, wherein the first screen and the second screen are Shack-Hartmann lenslet arrays.

18. The method of claim 12, wherein the second screen is rotated about 1to about 30 degrees relative to the first screen.

19. The method of claim 12, further comprising directing the light through a relay lens.

20. The method of claim 19, wherein the relay lens is placed between the second screen and the light detector.

21. The method of claim 19, wherein the relay lens is placed upstream of the first screen.

22. The method of claim 12, further comprising directing the light to a beam splitter positioned upstream of the first screen.

23. A method of measuring characteristics of an eye comprising:

a) directing light into the eye;

b) directing the light from the eye through a first screen comprising a first two-dimensional array of circular apertures;

c) directing the light from the first screen through a second screen comprising a second two-dimensional array of circular apertures, wherein the second screen is placed downstream of the first screen, the second screen is in a plane parallel to the first screen, and the second screen is rotated relative to the first screen;

d) detecting the light from the second screen at a light detector.

24. The method of claim 23, wherein the first two-dimensional array and the second two-dimensional array are identical.

25. The method of claim 23, wherein at least one screen is a Hartmann screen.

26. The method of claim 25, wherein the first screen and the second screen are Hartmann screens.

27. The method of claim 23, wherein at least one screen is a Shack-Hartmann lenslet array.

28. The method of claim 27, wherein the first screen and the second screen are Shack-Hartmann lenslet arrays.

29. The method of claim 23, wherein the second screen is rotated about 1to about 30 degrees relative to the first screen.

30. The method of claim 23, further comprising directing the light through a relay lens.

31. The method of claim 30, wherein the relay lens is placed between the second screen and the light detector.

32. The method of claim 30, wherein the relay lens is placed upstream of the first screen.

33. The method of claim 23, further comprising directing the light to a beam splitter positioned upstream of the first screen.