Systems, devices and methods for automatic microscopic focus

Patent metadata

Field	Value
Publication number	US-10247910-B1
Application number	US-201815920850-A
Country	US
Kind code	B1
Filing date	Mar 14, 2018
Priority date	Mar 14, 2018
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

An automatic focus system for an optical microscope that facilitates faster focusing by using at least two cameras. The first camera can be positioned in a first image forming conjugate plane and receives light from a first illumination source that transmits light in a first wavelength range. The second camera can be positioned at an offset distance from the first image forming conjugate plane and receives light from a second illumination source that transmits light in a second wavelength range.

First claim

What is claimed is:

1. A system for automatically focusing a microscope, comprising:
an objective;
a stage for positioning a specimen on a first image forming conjugate plane;
a first camera, configured for focusing, positioned on a second image forming conjugate plane;
a second camera, configured for focusing, positioned at an offset distance from the second image forming conjugate plane;
a primary illumination source that emits light in a first wavelength range, wherein the emitted light is received by the first camera;
a secondary illumination source that emits light in a second wavelength range which is different from the first wavelength range and that projects light through a focusing pattern that is positioned on a third image forming conjugate plane, wherein the projected light is received by the second camera; and
a hardware processor coupled to the first camera and the second camera that is configured to:
determine, using the first camera, when the specimen is in focus based on a sharpness value;
determine, using the second camera, a sharpness setpoint for the specimen when the specimen is determined to be in focus for the first camera;
after movement of the specimen, determine, using the second camera, a first sharpness value of the specimen;
determine whether the first sharpness value of the specimen is higher or lower than the sharpness setpoint; and
adjust a distance between the objective and the stage so that a second sharpness value of the specimen determined using the second camera corresponds to the sharpness setpoint.

2. The system of claim 1 , wherein the hardware processor is further configured to:
determine a sharpness curve for the specimen using the second camera; and
adjust the distance between the objective and the stage based on the sharpness curve so that the second sharpness value of the specimen determined using the second camera corresponds to the sharpness setpoint.

3. The system of claim 1 , further comprising:
a first filter positioned in an optical path between the secondary illumination source and the first camera to prevent light from the secondary illumination source from reaching the first camera; and
a second filter positioned in an optical path between the first illumination source and the second camera to prevent light from the first illumination source from reaching the second camera.

4. The system of claim 1 , wherein the first camera is also configured for taking images of the specimen when the specimen is determined to be in focus.

5. The system of claim 1 , further comprising a field diaphragm positioned in an optical path between the primary illumination source and the objective.

6. The system of claim 1 , wherein the hardware processor is further configured to cause at least one of the stage and the objective to be moved to achieve a coarse focus and a fine focus.

7. The system of claim 1 , wherein adjusting the distance between the objective and the stage so that the second sharpness value of the specimen determined using the second camera corresponds to the sharpness setpoint comprises repeatedly:
adjusting the distance between the objective and the stage;
determining the second sharpness value using the second camera; and
comparing the second sharpness value to the sharpness setpoint.

8. The system of claim 1 , wherein the hardware processor is further configured to save a position of the stage relative to the objective.

9. The system of claim 8 , wherein the saved position is used to determine a position of the second camera relative to the second image forming conjugate plane.

10. A system for automatically focusing a microscope, comprising:
an objective;
a stage for positioning a specimen on a first image forming conjugate plane;
a first camera, configured for taking images of the specimen when the specimen is determined to be in focus, positioned on a second image forming conjugate plane;
a second camera, configured for focusing, positioned on a third image forming conjugate plane;
a third camera, configured for focusing, positioned at an offset distance from the third image forming conjugate plane;
a primary illumination source that emits light in a first wavelength range, wherein the emitted light is received by the first camera;
a secondary illumination source that emits light in a second wavelength range which is different from the first wavelength range and that projects light through a focusing pattern that is positioned on a fourth image forming conjugate plane, wherein the projected light is received by the second and third camera; and
a hardware processor coupled to the second camera and the third camera that is configured to:
determine, using the second camera, when the specimen is in focus based on a sharpness value;
determine, using the third camera, a sharpness setpoint for the specimen when the specimen is determined to be in focus for the second camera;
after movement of the specimen, determine, using the third camera, a first sharpness value of the specimen;
determine whether the first sharpness value of the specimen is higher or lower than the sharpness setpoint; and
adjust a distance between the objective and the stage so that a second sharpness value of the specimen determined using the third camera corresponds to the sharpness setpoint.

11. The system of claim 10 , wherein the hardware processor is further configured to:
determine a sharpness curve for the specimen using the third camera; and
adjust the distance between the objective and the stage based on the sharpness curve so that the second sharpness value of the specimen determined using the third camera corresponds to the sharpness setpoint.

12. The system of claim 10 , further comprising:
a first filter positioned in an optical path between the secondary illumination source and the first camera to prevent light from the secondary illumination source from reaching the first camera; and
a second filter positioned in an optical path between the first illumination source and the second and third cameras to prevent light from the first illumination source from reaching the second and third cameras.

13. The system of claim 10 , further comprising a field diaphragm positioned in an optical path between the primary illumination source and the objective.

14. The system of claim 10 , wherein the hardware processor is further configured to cause at least one of the stage and the objective to be moved to achieve a coarse focus and a fine focus.

15. The system of claim 10 , wherein adjusting the distance between the objective and the stage so that the second sharpness value of the specimen determined using the third camera corresponds to the sharpness setpoint comprises repeatedly:
adjusting the distance between the objective and the stage;
determining the second sharpness value using the third camera; and
comparing the second sharpness value to the sharpness setpoint.

16. The system of claim 10 , wherein the hardware processor is configured to save a position of the stage relative to the objective.

17. The system of claim 16 , wherein the saved position is used to determine a position of the third camera relative to the third image forming conjugate plane.

18. A method for automatically focusing a microscope, comprising:
positioning a specimen on a stage on a first image forming conjugate plane;
positioning a first camera, configured for focusing, on a second image forming conjugate plane;
positioning a second camera, configured for focusing, at an offset distance from the se

Assignees

• Nanotronics Imaging Inc

Inventors

• Putman John B
• Putman Matthew C
• Orlando Julie
• Fashbaugh Dylan

Classifications

• G02B21/244 Primary

  using image analysis techniques · CPC title

• G02B7/285 Primary

  including two or more different focus detection devices, e.g. both an active and a passive focus detecting device · CPC title

• G02B21/26

  Stages; Adjusting means therefor · CPC title

• G02B21/365

  Control or image processing arrangements for digital or video microscopes (G02B21/361, G02B21/362 take precedence) · CPC title

• G02B21/06 Primary

  Means for illuminating specimens · CPC title