Apparatus and method for detecting lens thickness

1. A device for presenting an ophthalmic lens for inspection comprising:

an illumination source in optical connection with;

an imaging system adapted to measure the distance of the lens;

a measurement chamber in optical connection with said illumination source and said imaging system;

a rotating fixture connected to said measurement chamber via an adapter; and

a seat in said measurement chamber adapted to support a sample lens, wherein said seat is rotated by the rotating fixture, and

wherein said device is adapted to measure the thickness of said ophthalmic lens.

2. The device of claim 1 , wherein said imaging system further comprises a camera.

3. The device of claim 1 , wherein said imaging system further comprises a digital image sensor.

4. The device of claim 3 wherein said digital image sensor is selected from the group consisting of a CCD and a CMOS based imaging technology.

5. The device of claim 1 , wherein said imaging system further comprises a telecentric lens.

6. The device of claim 1 , wherein said imaging system further comprises a non-telecentric lens.

7. The imaging system of claim 6 where the images have been calibrated to reduce optical errors selected from the group consisting of parallax, distortion, and magnification errors.

8. The device of claim 1 , wherein said illumination source is selected from the group consisting of a collimated LED backlight, visible laser with a beam expander, laser diode, and a LED array.

9. The device of claim 1 , wherein said seat is dome-shaped.

10. The device of claim 1 , wherein said seat has a surface selected from the group consisting of multiple radii, aspheric surfaces, and an arbitrary spline-based surface.

11. The device of claim 1 , wherein said measurement chamber is adapted to contain a medium.

12. The device of claim 11 , wherein said medium is saline.

13. The device of claim 1 , wherein said rotating fixture further comprises a seal and a bearing that are connected to said measurement chamber via said adapter.

14. The device of claim 1 , further comprising a magnetic coupling that connects said rotating fixture to said measurement chamber.

15. The device of claim 1 , further comprising a vacuum line in fluid connection with said seat.

16. The device of claim 1 , wherein said measurement chamber has at least one window.

17. The device of claim 1 , wherein said seat is made of porous metal.

18. The device of claim 1 , wherein said seat is made of a plastic or metal material with a series of drilled holes for creating a vacuum.

19. A system for ophthalmic lens inspection comprising:

an illumination source in optical connection with an imaging system;

said imaging system adapted to measure the distance to said lens;

a measurement chamber in optical connection with said illumination source and said imaging system;

a rotating fixture connected to said measurement chamber via an adapter; and

a seat in said measurement chamber adapted to support a sample lens, wherein illumination source illuminates said sample lens to allow said imaging system to locate said lens and measure the thickness of said lens.

20. A method for measuring the thickness of an ophthalmic lens comprising:

providing an illumination source, imaging system comprising a digital image sensor and a measurement seat;

taking one set of images comprising the steps of:

taking a first image of said measurement seat;

placing a sample lens on said measurement seat; and

taking a second image of said lens on said measurement seat;

transforming said first and second images into first and second numerical data sets via said digital image sensor; and then

subtracting said second numerical data set from said first numerical data set to obtain a thickness measurement.

21. The method of claim 20 , further comprising providing a measurement chamber.

22. The method of claim 20 , further comprising providing a rotating fixture.

23. The method of claim 20 , further comprising taking more than one set of images.

24. The method of claim 20 , further comprising transforming said images into numerical data.

25. The method of claim 24 , further comprising analyzing said data.

26. The method of claim 24 , further comprising archiving said data.

27. A method for measuring the thickness of an ophthalmic lens comprising:

providing an illumination source, imaging system comprising a digital image sensor, a measurement chamber and a measurement seat;

calibrating the illumination source, imaging system, measurement chamber, and measurement seat;

filling the measurement chamber with a medium;

taking one set of images comprising the steps of:

finding the edge contour of the measurement seat;

taking a first image of said measurement seat;

activating a vacuum pump;

placing a sample lens on said measurement seat;

finding the edge contour of said sample lens; and

taking a second image of said lens on said measurement seat;

transforming said first and second images into first and second numerical data sets via said digital image sensor;

subtracting said second numerical data set from said first numerical data set to obtain a thickness measurement; and then

converting said thickness measurement to a three-dimensional thickness profile.

28. The method of claim 27 further comprising:

obtaining the front curve geometry of a sample lens, and

offsetting said front curve measurement by said thickness measurement to obtain the base curve surface.