Imaging system and method for multi-scale three-dimensional deformation or profile output

Patent metadata

Field	Value
Publication number	US-9823458-B2
Application number	US-201313955792-A
Country	US
Kind code	B2
Filing date	Jul 31, 2013
Priority date	Jul 31, 2012
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

An optical microscope system for 3D surface deformation and morphology measurement that can serve as a powerful tool in quality engineering and control, as well as in biological and materials research is described. The system was developed in part by combining the DAIC technique with optical microscopy. Decoding algorithms were derived for calculating the 3D displacement or profile of a micro-sized test sample from the in-plane displacement components of it first-order diffracted views.

First claim

What is claimed is:

1. A three-dimensional imaging system for a sample comprising:
an imaging system;
a first optical element positioned between the imaging system and a sample to provide an intermediate real image of at least a portion of a surface of the sample;
a second optical element positioned between the imaging system and the intermediate real image provided by the first optical element to provide a plurality of virtual images of the intermediate real image;
a narrow-band filter positioned between the imaging system and the second optical element to improve the quality of the plurality of virtual images by filtering out background light and suppressing chromatic dispersion of the second optical element;
a third optical element positioned between the second optical element and the imaging system and configured to project the plurality of virtual images onto the imaging system; and
a computer processor in communication with the imaging system for processing data related to the projected plurality of virtual images of the intermediate real image and for producing three-dimensional data of at least the portion of the surface of the sample.

2. The system of claim 1 , wherein the system is configured to provide sub-micron spatial resolution for three-dimensional surface displacement and profile measurements of the sample.

3. The system of claim 1 , wherein the first optical element comprises an objective.

4. The system of claim 1 , wherein the second optical element comprises a dispersive element that provides the plurality of virtual images that contain three-dimensional surface displacement and profile measurements of the sample.

5. The system of claim 1 , wherein the second optical element comprises a diffraction grating.

6. The system of claim 1 , wherein the third optical element comprises one or more relay lenses.

7. The system of claim 1 further comprising an energy source to energize at least a surface of the sample.

8. The system of claim 7 , wherein the energy source comprises an ultraviolet light source.

9. The system of claim 7 further comprising an energy source control to control the energization of at least a surface of the sample.

10. The system of claim 9 , wherein the energy source control comprises a diaphragm to control the one or both of the size and location of the area of the surface energized.

11. A three-dimensional imaging system providing sub-micron spatial resolution for three-dimensional surface displacement and profile measurements of a sample comprising:
an illumination path used to illuminate at least a portion of a surface of a sample;
an imaging path used to generate a full-field image of the portion of the surface of the sample;
an imaging system located in the imaging path;
an objective located in the imaging path, and positioned between the imaging system and the sample to produce an intermediate real image of the portion of the surface of the sample;
a diffraction grating located in the imaging path, and positioned between the imaging system and the intermediate real image produced by the objective to produce a plurality of virtual images of the intermediate real image, the plurality of virtual images containing three-dimensional surface displacement and profile measurements of the sample;
a narrow-band filter located in the imaging path, and positioned between the imaging system and the diffraction grating to improve the quality of the plurality of virtual images by filtering out background light and suppressing chromatic dispersion of the diffraction grating;
one or more relay lenses located in the imaging path, and for projecting the plurality of virtual images of the portion of the surface of the sample to the imaging system; and
a computer processor in communication with the imaging system for processing data related to the projected plurality of virtual images of the intermediate real image, and for producing sub-micron spatial resolution three-dimensional data of the portion of the surface of the sample.

12. The system of claim 11 further comprising a beamsplitter to couple the illumination path into the imaging path.

13. The system of claim 11 further comprising an ultraviolet light source for the illumination path and an iris diaphragm in the illumination path to control one or both of the size and location of the area of the surface illuminated.

14. The system of claim 12 further comprising a condenser lens and reflecting mirror in the illumination path.

15. A method of three-dimensional imaging comprising:
directing an imaging system at a first optical element positioned between the imaging system and a sample;
forming an intermediate real image of at least a surface of the sample;
forming a plurality of virtual images of the intermediate real image;
performing narrow-band filtering on the plurality of virtual images to improve the quality of the plurality of virtual images by filtering out background light and suppressing chromatic dispersion;
projecting the plurality of virtual images onto the imaging system; and
processing data related to the projected plurality of virtual images of the intermediate real image to produce sub-micron spatial resolution three-dimensional data of at least a surface of the sample.

16. The method of claim 15 , wherein forming a plurality of virtual images of the intermediate real image comprises forming a plurality of virtual images of the intermediate real image via a second optical element positioned between the imaging system and the first optical element.

17. The method of claim 15 further comprising projecting a real image of at least a surface of the sample to the imaging system;
wherein processing data comprises processing data related to the real image and the plurality of virtual images of the intermediate real image to produce sub-micron spatial resolution three-dimensional data of at least a surface of the sample.

18. The system of claim 1 , wherein
the producing the three-dimensional data comprises:
calculating a full-field displacement of the portion of the surface of the sample based on a two first order virtual images of the plurality of virtual images; and
determining a three-dimension surface profile of the portion of the surface of the sample based on the calculated displacement, and

the determining a three-dimension surface profile comprises calculating a depth at a point (x p , y p ) on the portion of the surface based on the function:
h ( x p , y p )=β( x p + ″ −x p − ″ ),

where β is a free parameter that can be calibrated against a known 3D displacement field, and x + ″ and x − is the relative displacement between two first order virtual images of the plurality of virtual images.

19. The system of claim 18 , wherein
the second optical element comprises a diffraction grating having a first-order diffraction angle θ and an objective lens having a magnification factor N, and
β may be calculated based on the function:

β
=

-

1

N
*
M
*
tan
⁢

⁢
θ

Assignees

• Georgia Tech Res Inst

Inventors

• Xia Shuman
• Zhang Jingwen

Classifications

• H04N13/207

  using a single two-dimensional [2D] image sensor · CPC title

• G02B27/48

  Laser speckle optics · CPC title

• G02B21/0016

  Technical microscopes, e.g. for inspection or measuring in industrial production processes · CPC title

• G02B27/1093

  for use with monochromatic radiation only, e.g. devices for splitting a single laser source · CPC title

• G01B9/04

  Measuring microscopes · CPC title