# US 11,079,618 B2 · Imaging system and imaging method

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- Number: US 11,079,618 B2
- Document ID: US11079618B2
- Status: Granted
- Kind: B2
- Application number: 16/089,400
- Filed: 2017-03-15
- Published: 2020-09-24
- Granted: 2021-08-03
- Earliest claimed: 2016-03-30
- Assignees: Hamamatsu Photonics K.K.
- Applicants: Hamamatsu Photonics K.K.
- Inventors: Koyo Watanabe; Koji Takahashi; Takashi Inoue; Haruyasu Ito
- Web page: https://patentgrep.com/patent/US11079618B2

## CPC

- G02F 1/0105: {Illuminating devices}
- G01N 21/00: Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light (G01N3/00 - G01N19/00 take precedence)
- G02B 5/3016: {involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528)}
- G02B 5/3025: {Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state (G02B5/3008, G02B5/3016 take precedence)}
- G02B 5/3083: {Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001)}
- G02F 1/0136: {for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation (G02F1/0353 takes precedence)}
- G03B 15/00: Special procedures for taking photographs; Apparatus therefor
- H04N 23/56: provided with illuminating means
- H04N 23/671: {in combination with active ranging signals, e.g. using light or sound signals emitted toward objects}
- H04N 23/75: by influencing optical camera components
- H04N 23/60: Control of cameras or camera modules
- 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
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An imaging system includes a light source for outputting initial pulsed light, a polarization control unit for rotating a polarization plane of the initial pulsed light, an optical pulse shaping unit for inputting the initial pulsed light with the rotated polarization plane, and outputting first pulsed light Lp1 having a first polarization direction and second pulsed light Lp2 having a second polarization direction different from the first polarization direction with a time, an irradiation optical system for irradiating an imaging object with the pulsed light Lp1 and the pulsed light Lp2, a light separation element for separating the pulsed light Lp1 and the pulsed light Lp2 reflected by or transmitted through the imaging object on the basis of the polarization directions, an imaging unit for imaging the pulsed light Lp1, and an imaging unit for imaging the pulsed light Lp2.

## Claims

### Claim 1

An imaging system comprising:
a light source configured to output at least one initial pulsed light;
a polarization controller configured to rotate a polarization plane of the initial pulsed light;
an optical pulse shaper configured to input the initial pulsed light with the rotated polarization plane, and output first pulsed light having a first polarization direction and second pulsed light having a second polarization direction different from the first polarization direction with a time difference from each other;
an irradiation optical system configured to irradiate an imaging object with the first pulsed light and the second pulsed light;
a light separator configured to separate the first pulsed light and the second pulsed light reflected by or transmitted through the imaging object on the basis of the polarization directions;
a first camera configured to capture an image of the separated first pulsed light; and
a second camera configured to capture an image of the separated second pulsed light,
wherein the optical pulse shaper includes:
a dispersive element configured to disperse the initial pulsed light with the rotated polarization plane for respective wavelengths, and
a polarization dependent type spatial light modulator having a modulation function in the first polarization direction and not having a modulation function in the second polarization direction, and
wherein the spatial light modulator modulates only the polarization component of the initial pulsed light along the first polarization direction so that the second pulsed light, and the first pulsed light having the time difference with respect to the second pulsed light are generated.

### Claim 2 (depends on 1)

The imaging system according to claim 1, wherein the spatial light modulator is configured to input the initial pulsed light with the polarization plane rotated with respect to the first polarization direction and dispersed for respective wavelengths, and modulate a phase spectrum of a polarization component in the first polarization direction included in the initial pulsed light.

### Claim 3 (depends on 1)

The imaging system according to claim 1, wherein a polarization plane rotation angle of the polarization controller is changeable.

### Claim 4 (depends on 1)

The imaging system according to claim 1, wherein the first camera includes a first imaging element, and the second camera includes a second imaging element different from the first imaging element.

### Claim 5 (depends on 1)

The imaging system according to claim 1, wherein the first camera and the second camera include a common imaging element.

### Claim 6

An imaging method comprising:
outputting at least one initial pulsed light;
rotating a polarization plane of the initial pulsed light;
performing an optical pulse shaping of inputting the initial pulsed light with the rotated polarization plane, and outputting first pulsed light having a first polarization direction and second pulsed light having a second polarization direction different from the first polarization direction with a time difference from each other;
irradiating an imaging object with the first pulsed light and the second pulsed light;
separating the first pulsed light and the second pulsed light reflected by or transmitted through the imaging object on the basis of the polarization directions; and
capturing images of the separated first pulsed light and the second pulsed light,
wherein the optical pulse shaping includes inputting the pulsed light with the rotated polarization plane and dispersed for respective wavelengths to a spatial light modulator, and modulating, by the spatial light modulator, a phase spectrum of a polarization component in the first polarization direction included in the initial pulsed light,
wherein the spatial light modulator is a polarization dependent type spatial light modulator having a modulation function in the first polarization direction and not having a modulation function in the second polarization direction, and
wherein the spatial light modulator modulates only the polarization component of the initial pulsed light along the first polarization direction so that the second pulsed light, and the first pulsed light having the time difference with respect to the second pulsed light are generated.