Digital determination of focus position

Patent metadata

Field	Value
Publication number	US-11460683-B2
Application number	US-201816624729-A
Country	US
Kind code	B2
Filing date	Jun 21, 2018
Priority date	Jul 5, 2017
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

A detection optical unit (112) of an optical apparatus is configured to produce an imaged representation (151, 152) of a sample object (150) on a detector (114). An adjustable filter element (119) is arranged in a beam path of the detection optical unit (112) that defines the imaged representation (151, 152). A controller is configured to drive the adjustable filter element (119) to filter the spectrum of the beam path with a first filter pattern (301-308) and with a second filter pattern (301-308) and to drive the detector (114) to capture a first image, associated with the first filter pattern (301-308), and to capture a second image, which is associated with the second filter pattern (301-308). The controller is furthermore configured to determine a focus position (181) of the sample object (150) based on the first image and the second image. The first filter element (301-308) here defines a first line and the second filter element (301-308) defines a second line.

First claim

The invention claimed is:

1. An optical apparatus, comprising:
a detector;
a detection optical unit configured to produce an imaged representation of a sample object on the detector, wherein the detection optical unit comprises an adjustable filter element in a beam path of the detection optical unit, the beam path defining the imaged representation; and
a controller configured to drive the adjustable filter element to filter a spectrum of the beam path with a first filter pattern and with a second filter pattern, and to drive the detector to capture a first image associated with the first filter pattern, and to capture a second image associated with the second filter pattern,
wherein the controller is further configured to determine a focus position of the sample object based on the first image and the second image,
wherein the first filter pattern comprises a first line-shaped transmissive region that is off-axis, and
wherein the second filter pattern comprises a second line-shaped transmissive region that is off-axis.

2. The optical apparatus as claimed in claim 1 ,
wherein the controller is further configured to drive a user interface of the optical apparatus to output a user instruction based on the focus position.

3. The optical apparatus as claimed in claim 1 ,
wherein the controller is configured to determine a distance of a position of the imaged representation of the sample object in the first image from a position of the imaged representation of the sample object in the second image, and
wherein the controller is further configured to determine the focus position based on the distance.

4. The optical apparatus as claimed in claim 3 ,
wherein the controller is configured to determine the distance based on one or more of one-dimensional or two-dimensional correlation of the first image with the second image, object detection of the sample object in the first image and in the second image, and landmark detection in the first image and in the second image.

5. The optical apparatus as claimed in claim 1 ,
wherein the first filter pattern is transformed into the second filter pattern by translation along a vector.

6. The optical apparatus as claimed in claim 5 ,
wherein the controller is configured to determine a distance of a position of the imaged representation of the sample object in the first image from a position of the imaged representation of the sample object in the second image,
wherein the controller is further configured to determine the focus position based on the distance, and
wherein the controller is configured to determine the distance based on an orientation of the vector.

7. The optical apparatus as claimed in claim 1 ,
wherein the first line-shaped transmissive region extends parallel to the second line-shaped transmissive region along at least 50% of its length.

8. The optical apparatus as claimed in claim 1 ,
wherein the adjustable filter element comprises at least one of a filter wheel, a digital micromirror device, a liquid crystal filter, a movable filter plates, or an amplitude filter element.

9. The optical apparatus as claimed in claim 1 ,
wherein the first filter pattern allows transmission of light in a first wavelength range or with a first polarization,
wherein the second filter pattern allows transmission of light in a second wavelength range or with a second polarization,
wherein the first wavelength range or the first polarization differs from the second wavelength range or the second polarization,
wherein the first image represents the first wavelength range, and
wherein the second image represents the second wavelength range.

10. The optical apparatus as claimed in claim 1 ,
wherein the first line-shaped transmissive region of the first filter pattern or the second line-shaped transmissive region of the second filter pattern is formed by a plurality of holes, and
wherein ones of the plurality of holes are spaced apart from one another.

11. The optical apparatus as claimed in claim 1 ,
wherein the first line-shaped transmissive region of the first filter pattern is straight or curved.

12. The optical apparatus as claimed in claim 1 ,
wherein the second line-shaped transmissive region of the second filter pattern is straight or curved.

13. A method, comprising:
driving a filter element, which is in a beam path that defines an imaged representation of a sample object, for filtering a spectrum of the beam path with a first filter pattern and with a second filter pattern;
driving a detector to capture a first image associated with the first filter pattern, and to capture a second image associated with the second filter pattern; and
determining a focus position of the sample object based on the first image and the second image,
wherein the first filter pattern comprises a first line-shaped transmissive region that is off-axis, and
wherein the second filter pattern comprises a second line-shaped transmissive region that is off-axis.

14. An optical apparatus, comprising:
a detector;
a detection optical unit configured to produce an imaged representation of a sample object on the detector, wherein the detection optical unit comprises an adjustable filter element in a beam path of the detection optical unit, the beam path defining the imaged representation; and
a controller configured to drive the adjustable filter element to filter rays of the beam path with a first filter pattern and with a second filter pattern that respectively have a first angle in relation to a sensor surface of the detector and that have a second angle in relation to the sensor surface,
wherein the controller is further configured to drive the detector to capture a first image associated with the rays having the first angle, and to capture a second image associated with the rays having the second angle,
wherein the controller is further configured to determine a focus position of the sample object based on the first image and the second image,
wherein the first filter pattern comprises a first line-shaped transmissive region that is off-axis, and
wherein the second filter pattern comprises a second line-shaped transmissive region that is off-axis.

15. A method, comprising:
driving a filter element in a beam path that defines an imaged representation of a sample object, to filter rays of the beam path with a first filter pattern and with a second filter pattern that respectively have a first angle in relation to a sensor surface of a detector and that have a second angle in relation to the sensor surface;
driving the detector to capture a first image associated with the rays having the first angle, and to capture a second image associated with the rays having the second angle; and
determining a focus position of the sample object based on the first image and the second image,
wherein the first filter pattern comprises a first line-shaped transmissive region that is off-axis, and
wherein the second filter pattern comprises a second line-shaped transmissive region that is off-axis.

16. The optical apparatus as claimed in claim 1 ,
wherein the adjustable filter element is in a pupil plane of the beam path to form an aperture stop that is offset from the first line-shaped transmissive region and the second line-shaped transmissive region.

17. The optical apparatus as claimed in claim 1 ,
wherein the first line-shaped transmissive region is off-axis relative to an axis defined by the beam path, and
wherein the second line-shaped transmissive region is off-axis relative to the axis defined by the beam path.

Assignees

• Zeiss Carl Microscopy Gmbh

Inventors

• Stoppe Lars
• Milde Thomas
• Berner Andrea

Classifications

• G01B11/026 Primary

  by measuring distance between sensor and object (G01B11/0608 takes precedence) · CPC title

• G03B11/00

  Filters or other obturators specially adapted for photographic purposes · CPC title

• G02B26/007

  the movable or deformable optical element controlling the colour, i.e. a spectral characteristic, of the light · CPC title

• G01B11/0608

  Height gauges · CPC title

• G02B21/244 Primary

  using image analysis techniques · CPC title