# US 11,994,661 B2 · Simultaneous focusing of an optical system to multiple focal planes using liquid crystal polarization lenses

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- Number: US 11,994,661 B2
- Document ID: US11994661B2
- Status: Granted
- Kind: B2
- Application number: 18/258,315
- Filed: 2022-02-04
- Published: 2023-12-14
- Granted: 2024-05-28
- Earliest claimed: 2021-02-05
- Assignees: Meadowlark Optics, Inc.
- Applicants: Meadowlark Optics, Inc.
- Inventors: Christopher Hoy; Janelle Shane; Douglas J. McKnight
- Web page: https://patentgrep.com/patent/US11994661B2

## CPC

- G02B 21/0092: {Polarisation microscopes}
- G02B 21/367: {providing an output produced by processing a plurality of individual source images, e.g. image tiling, montage, composite images, depth sectioning, image comparison}
- G02B 21/0056: {based on optical coherence, e.g. phase-contrast arrangements, interference arrangements}
- G02B 21/006: {focusing arrangements; selection of the plane to be imaged}
- G02F 1/1313: {specially adapted for a particular application}
- G02F 1/294: {Variable focal length devices}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

This disclosure describes systems, methods, and apparatus for an optical system including pairs of LCPGs and polarization controllers (e.g., waveplates) that can be controlled to effect multiple simultaneous focal planes, or to simultaneously image multiple focal planes.

## Claims

### Claim 1

An optical system with a controllable liquid crystal polarization grating (LCPG) stack configured to produce or image two or more simultaneous focal planes, the optical system comprising:
a first LCPG lens;
a second LCPG lens;
a first polarization controller configured to selectively adjust a polarization entering the first LCPG lens, and a second polarization controller configured to selectively adjust a polarization entering the second LCPG lens, thereby controlling a number and location of each of the two or more simultaneous focal planes.

### Claim 2 (depends on 1)

The optical system of claim 1, wherein the two or more simultaneous focal planes have polarization contrast.

### Claim 3 (depends on 1)

The optical system of claim 1, wherein the first and second LCPG lenses are individually-controllable.

### Claim 4 (depends on 1)

The optical system of claim 1, wherein the first and second LCPG lenses are arranged between two or more lenses of a microscope.

### Claim 5 (depends on 4)

The optical system of claim 4, wherein the first LCPG lens is arranged at or near a back aperture of a microscope objective or at or near a conjugate to a plane of the microscope objective.

### Claim 6 (depends on 5)

The optical system of claim 5, wherein the second LCPG lens is arranged at or near a back aperture of the microscope objective or at or near the conjugate to the plane of the microscope objective.

### Claim 7 (depends on 6)

The optical system of claim 6, wherein the second polarization controller is arranged at or near the back aperture of the microscope objective or at or near the conjugate to the plane of the microscope objective.

### Claim 8 (depends on 1)

The optical system of claim 1, wherein the first polarization controller is arranged at or near a back aperture of a microscope objective or at or near a conjugate to a plane of the microscope objective.

### Claim 9 (depends on 8)

The optical system of claim 8, wherein mechanical adjustment of the controllable LCPG stack, an objective of the microscope, or a sample of the microscope is used for finer adjustment of the two or more simultaneous focal planes while waveplate control is used for one or more of faster adjustments and larger adjustments.

### Claim 10 (depends on 1)

The optical system of claim 1, wherein at least one of the first or the second polarization controllers is non-uniform.

### Claim 11 (depends on 10)

The optical system of claim 10, wherein at least one of the first or the second polarization controllers is a segmented waveplate or a gradient waveplate.

### Claim 12 (depends on 11)

The optical system of claim 11, wherein an illumination of each of the two or more simultaneous focal planes is dependent upon a size and number of controlled regions in the segmented waveplate.

### Claim 13 (depends on 11)

The optical system of claim 11, wherein the optical system is part of a phase-contrast or darkfield imaging system.

### Claim 14 (depends on 1)

The optical system of claim 1, wherein the two or more simultaneous focal planes are frequency tagged.

### Claim 15 (depends on 1)

The optical system of claim 1, wherein at least one of the first or the second polarization controllers is selected from: a waveplate switch, a passive waveplate, a segmented and/or pixelated waveplate, a gradient waveplate, a spatial light modulator, a polarizer, and a guest-host liquid crystal device.

### Claim 16

A dynamic focusing system comprising:
a light source;
an imaging sensor;
a first liquid crystal polarization grating (LCPG) lens;
a first polarization controller configured to control a polarization of polarized light entering the first LCPG lens;
a second LCPG lens;
a second polarization controller configured to control a polarization of polarized light entering the second LCPG lens;
a waveplate controller electrically coupled to the first and second polarization controllers and configured to control a state of the first polarization controller and a state of the second polarization controller to control two or more simultaneous focal planes of the dynamic focusing system.

### Claim 17 (depends on 16)

The dynamic focusing system of claim 16, wherein the light source and the imaging sensor are on opposing sides of the two or more simultaneous focal planes.

### Claim 18 (depends on 17)

The dynamic focusing system of claim 17, wherein the light source and the imaging sensor are separated from the two or more simultaneous focal planes by at least a third LCPG lens and a third polarization controller.

### Claim 19 (depends on 16)

The dynamic focusing system of claim 16, wherein the light source and the imaging sensor are on the same side of the two or more simultaneous focal planes.

### Claim 20 (depends on 16)

The dynamic focusing system of claim 16, wherein the waveplate controller is configured to select a number and location of each of the two or more simultaneous focal planes.

### Claim 21 (depends on 16)

The dynamic focusing system of claim 16, wherein at least one of the first and second polarization controllers is non-uniform.

### Claim 22 (depends on 16)

The dynamic focusing system of claim 16, wherein the two or more simultaneous focal planes have polarization contrast.

### Claim 23 (depends on 16)

The dynamic focusing system of claim 16, wherein the two or more simultaneous focal planes exist simultaneously.

### Claim 24 (depends on 16)

The dynamic focusing system of claim 16, wherein the first and second LCPG lenses are individually-controllable.

### Claim 25 (depends on 16)

The dynamic focusing system of claim 16, wherein the first and second LCPG lenses are arranged between two or more lenses of a microscope.

### Claim 26 (depends on 25)

The dynamic focusing system of claim 25, wherein the first LCPG lens is arranged at or near a back aperture of a microscope objective or at or near a conjugate to a plane of the microscope objective.

### Claim 27 (depends on 26)

The dynamic focusing system of claim 26, wherein the second LCPG lens is arranged at or near a back aperture of the microscope objective or at or near the conjugate to the plane of the microscope objective.

### Claim 28 (depends on 27)

The dynamic focusing system of claim 27, wherein the first polarization controller is arranged at or near the back aperture of the microscope objective or at or near the conjugate to the plane of the microscope objective.

### Claim 29 (depends on 16)

The dynamic focusing system of claim 16, wherein the first polarization controller is arranged at or near a back aperture of a microscope objective or at or near a conjugate to a plane of the microscope objective.

### Claim 30 (depends on 29)

The dynamic focusing system of claim 29, wherein mechanical adjustment of a LCPG stack, an objective of the microscope, or a sample of the microscope, is used for finer adjustment of one or more simultaneous focal planes while waveplate control is used for one or more of faster adjustments and larger adjustments, and wherein the LCPG stack comprises at least the first LCPG lens, the second LCPG lens, the first polarization controller, and the second polarization controller.

### Claim 31 (depends on 16)

The dynamic focusing system of claim 16, wherein at least one of the first and the second polarization controllers is non-uniform.

### Claim 32 (depends on 31)

The dynamic focusing system of claim 31, wherein at least one of the first and the second polarization controllers is a segmented waveplate or a gradient waveplate.

### Claim 33 (depends on 32)

The dynamic focusing system of claim 32, wherein an illumination of each of the two or more simultaneous focal planes is dependent upon a size and number of controlled regions in the segmented waveplate.

### Claim 34 (depends on 32)

The dynamic focusing system of claim 32, wherein the dynamic focusing system is part of a phase-contrast or darkfield imaging system.

### Claim 35 (depends on 16)

The dynamic focusing system of claim 16, wherein the two or more simultaneous focal planes are frequency tagged.

### Claim 36 (depends on 16)

The dynamic focusing system of claim 16, wherein at least one of the first and second polarization controllers is selected from: a waveplate switch, a passive waveplate, a segmented and/or pixelated waveplate, a gradient waveplate, a spatial light modulator, a polarizer, and a guest-host liquid crystal device.

### Claim 37

A method of dynamic focusing to produce or image two or more simultaneous focal planes, the method comprising:
providing a light source or imaging device;
providing a first liquid crystal polarization grating (LCPG)-polarization controller optical stack comprising at least one LCPG and at least a first polarization controller;
providing a second LCPG-polarization controller optical stack comprising at least a second polarization controller;
directing polarized light through the first and second LCPG-polarization controller optical stacks; and
selecting a state of the first and second polarization controllers to select a number and location of the two or more simultaneous focal planes.

### Claim 38 (depends on 37)

The method of claim 37, further comprising providing a first focusing optical assembly between the light source or the imaging device and the first LCPG-polarization controller optical stack.

### Claim 39 (depends on 38)

The method of claim 38, further comprising providing a second focusing optical assembly between the first LCPG-polarization controller optical stack and the two or more simultaneous focal planes.

### Claim 40 (depends on 39)

The method of claim 39, further comprising moving either or both of the first and second focusing optical assemblies to effect finer adjustments to the two or more simultaneous focal planes.

### Claim 41 (depends on 37)

The method of claim 37, further comprising providing a focusing optical assembly between the first LCPG-polarization controller optical stack and the two or more simultaneous focal planes.

### Claim 42 (depends on 37)

The method of claim 37, further comprising selectively imaging one or more of the two or more simultaneous focal planes using the second LCPG-polarization controller optical stack arranged between the two or more simultaneous focal planes and the imaging device.

### Claim 43

An optical system comprising:
a light source or imaging device;
a first liquid crystal polarization grating (LCPG)-polarization controller optical stack comprising at least one LCPG and at least a first polarization controller, and wherein polarized light is directed through the first LCPG-polarization controller optical stack;
a second LCPG-polarization controller optical stack comprising at least one LCPG and at least a second polarization controller, and wherein polarized light is directed through the second LCPG-polarization controller optical stack; and
a waveplate controller comprising a non-transitory, tangible computer readable storage medium, encoded with processor readable instructions, wherein the waveplate controller is configured for dynamic focusing to produce or image two or more simultaneous focal planes, wherein the dynamic focusing is based at least in part on,
instructing the first and second polarization controllers to switch between states thereby changing a number and/or location of the two or more simultaneous focal planes.

### Claim 44 (depends on 43)

The optical system of claim 43, further comprising a first focusing optical assembly between the light source or the imaging device and the first LCPG-polarization controller optical stack.

### Claim 45 (depends on 44)

The optical system of claim 44, further comprising a second focusing optical assembly between the first LCPG-polarization controller optical stack and the two or more simultaneous focal planes.

### Claim 46 (depends on 45)

The optical system of claim 45, wherein the dynamic focusing is further based on moving either or both of the first and second focusing optical assemblies to effect finer adjustments to the two or more simultaneous focal planes.

### Claim 47 (depends on 43)

The optical system of claim 43, further comprising a focusing optical assembly between the first LCPG-polarization controller optical stack and the two or more simultaneous focal planes.