Chromatic confocal system

Patent metadata

Field	Value
Publication number	US-9752867-B2
Application number	US-201514980337-A
Country	US
Kind code	B2
Filing date	Dec 28, 2015
Priority date	Jul 3, 2014
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A system for determining surface topography of a three-dimensional structure is provided. The system can include an illumination unit configured to output a two-dimensional array of light beams each comprising a plurality of wavelengths. An optical assembly can focus the plurality of wavelengths of each light beam to a plurality of focal lengths so as to simultaneously illuminate the structure over a two-dimensional field of view. A detector and a processor are used to generate data representative of the surface topography of the three-dimensional structure based on the measured characteristics of the light reflected from the structure.

First claim

What is claimed is:

1. A system for measuring surface topography of a three-dimensional structure, the system comprising:
an illumination unit configured to output a two-dimensional array of light beams each comprising a plurality of wavelengths;
an optical assembly operatively coupled to the illumination unit and configured to focus the plurality of wavelengths of each light beam to a plurality of focal lengths relative to the optical assembly so as to simultaneously illuminate the three-dimensional structure over a two-dimensional field of view, wherein the plurality of focal lengths is fixed relative to the optical assembly during the measuring of the surface topography; and
a detector configured to measure a characteristic of light reflected from the three-dimensional structure for each of a plurality of locations distributed in two dimensions over the two-dimensional field of view.

2. The system of claim 1 , wherein the characteristic comprises an intensity.

3. The system of claim 1 , wherein the plurality of wavelengths comprises wavelengths from 400 nm to 800 nm.

4. The system of claim 1 , wherein the plurality of wavelengths comprises at least three spectral bands, and wherein the at least three spectral bands comprise overlapping wavelengths of light.

5. The system of claim 1 , wherein the plurality of wavelengths comprises a continuous spectrum of wavelengths.

6. The system of claim 1 , wherein the two-dimensional array of light beams forms a two-dimensional array of spots on the three-dimensional structure over the two-dimensional field of view, and wherein a ratio of pitch to spot size for the two-dimensional array of spots is configured to inhibit cross-talk between the two-dimensional array of spots.

7. The system of claim 1 , wherein the optical assembly is configured to focus the light beams of the two-dimensional array to the plurality of focal lengths using at least one optical component with longitudinal chromatic aberration.

8. The system of claim 1 , wherein the plurality of focal lengths covers a depth of at least 20 mm.

9. The system of claim 2 , wherein the detector comprises a plurality of sensor elements distributed over a surface area configured to receive the light reflected from the three-dimensional structure over the two-dimensional field of view.

10. The system of claim 9 , wherein each sensor element of the plurality of sensor elements is configured to measure the intensity of at least one wavelength of the light reflected from the three-dimensional structure.

11. The system of claim 10 , wherein the plurality of sensor elements comprises a plurality of red sensor elements, a plurality of green sensor elements, and a plurality of blue sensor elements; each of the plurality of red sensor elements being configured to measure the intensity of a red light wavelength, each of the plurality of green sensor elements being configured to measure the intensity of a green light wavelength, and each of the plurality of blue sensor elements being configured to measure the intensity of a blue light wavelength.

12. The system of claim 11 , wherein the plurality of sensor elements are arranged in a Bayer pattern or in a plurality of layers.

13. The system of claim 1 , wherein the optical assembly is configured to focus the plurality of wavelengths to the plurality of focal lengths to a depth within a range from 10 mm to 30 mm relative to the optical assembly without relative movement of components of the optical assembly and components of the illumination unit.

14. A method for measuring surface topography of a three-dimensional structure, the method comprising:
generating a two-dimensional array of light beams each comprising a plurality of wavelengths;
focusing the plurality of wavelengths of each light beam to a plurality of focal lengths relative to the three-dimensional structure so as to simultaneously illuminate the three-dimensional structure over a two-dimensional field of view, wherein the plurality of focal lengths is fixed relative to the optical assembly during the measuring of the surface topography; and
measuring a characteristic of light reflected from the three-dimensional structure for each of a plurality of locations distributed in two dimensions over the two-dimensional field of view.

15. The method of claim 14 , wherein the characteristic comprises an intensity.

16. The method of claim 14 , wherein the plurality of wavelengths comprises wavelengths from 400 nm to 800 nm.

17. The method of claim 14 , wherein the plurality of wavelengths comprises at least three spectral bands, and wherein the at least three spectral bands comprise overlapping wavelengths of light.

18. The method of claim 14 , wherein the plurality of wavelengths comprises a continuous spectrum of wavelengths.

19. The method of claim 14 , wherein the two-dimensional array of light beams forms a two-dimensional array of spots on the structure over the two-dimensional field of view, and wherein a ratio of pitch to spot size for the two-dimensional array of spots is selected to inhibit cross-talk between the two-dimensional array of spots.

20. The method of claim 14 , wherein the light beams of the two-dimensional array are focused to the plurality of focal lengths using at least one optical component with longitudinal chromatic aberration.

21. The method of claim 14 , wherein the plurality of focal lengths covers a depth of at least 20 mm.

22. The method of claim 15 , wherein the intensity of the light reflected from the three-dimensional structure is measured using a detector comprising a plurality of sensor elements distributed over a surface area configured to receive the light reflected from the three-dimensional structure over the two-dimensional field of view.

23. The method of claim 22 , wherein each sensor element of the plurality of sensor elements is configured to measure the intensity of at least one wavelength of the light reflected from the three-dimensional structure.

24. The method of claim 23 , wherein the plurality of sensor elements comprises a plurality of red sensor elements, a plurality of green sensor elements, and a plurality of blue sensor elements; each of the plurality of red sensor elements being configured to measure the intensity of a red light wavelength, each of the plurality of green sensor elements being configured to measure the intensity of a green light wavelenath, and each of the plurality of blue sensor elements being configured to measure the intensity of a blue light wavelength.

25. The method of claim 24 , wherein the plurality of sensor elements are arranged in a Bayer pattern or in a plurality of layers.

26. The method of claim 14 , wherein the focusing of the plurality of wavelengths to the plurality of focal lengths to a depth within a range from 10 mm to 30 mm is performed without relative movement of components of an optical assembly and components of an illumination unit.

Assignees

• Align Technology Inc

Inventors

• Atiya Yossef
• Verker Tal

Classifications

• A61B1/06

  with illuminating arrangements · CPC title

• A61B1/04

  combined with photographic or television appliances · CPC title

• A61B1/00009

  of image signals during a use of endoscope · CPC title

• A61B1/0605

  for spatially modulated illumination · CPC title

• A61B1/00194

  adapted for three-dimensional imaging · CPC title