# US 2018/0322976 A1 · Optical tweezers device

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- Number: US 2018/0322976 A1
- Document ID: US20180322976A1
- Status: Published application
- Kind: A1
- Application number: 15/770,781
- Filed: 2016-10-21
- Published: 2018-11-08
- Earliest claimed: 2015-10-28
- Assignees: Jtekt Corporation
- Applicants: Jtekt Corporation
- Inventors: Kota NANRI; Toshiyuki SAITO; Kensuke SUZUKI
- Web page: https://patentgrep.com/patent/US20180322976A1

## CPC

- G21K 1/30: for confining neutral particles or handling confined neutral particles, e.g. atom traps
- B25J 7/00: Micromanipulators {(specimen supports for investigating or analysing materials G01N23/2204; associated with microscopes G02B21/32; means for supporting or positioning the objects or the material in discharge tubes H01J37/20)}
- G02B 21/06: Means for illuminating specimens
- G02B 21/32: Micromanipulators structurally combined with microscopes
- G02B 21/361: {Optical details, e.g. image relay to the camera or image sensor (G02B21/364 takes precedence; illumination details G02B21/06 and subgroups)}
- G02B 21/086: {for transillumination only}
- G21K: HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
- B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50})
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An optical tweezers device determines trapping force data indicating a trapping force for a particle on the basis of a distance between the particle trapped by focusing laser beam with a lens and a focal point of the lens. The optical tweezers device determines a difference between a trapping force theoretical value that is estimated according to a linear relationship between the distance between the trapped particle and the focal point of the lens and the trapping force for the particle and the trapping force indicated by the trapping force data. The optical tweezers device controls a laser power of the light source on the basis of the difference of the trapping force.

## Claims

### Claim 1

An optical tweezers device comprising:
a light source which emits a laser beam;
a lens which focuses the laser beam emitted from the light source;
a drive unit which moves, relative to each other, a particle trapped by focusing the laser beam with the lens and an object located in the vicinity of the particle;
a detector which outputs a detection signal for determination of a distance between the trapped particle and a focal point of the lens;
a trapping force calculation unit which determines trapping force data indicating a trapping force for the particle on the basis of the distance determined from the detection signal;
a difference calculation unit which determines a difference between a trapping force theoretical value that is estimated according to a linear relationship between the distance between the trapped particle and the focal point of the lens and the trapping force for the particle and the trapping force indicated by the trapping force data; and
an output control unit which controls a laser power of the light source on the basis of the difference of the trapping force.

### Claim 2 (depends on 1)

The optical tweezers device according to claim 1,
wherein the difference calculation unit converts the difference into a current value input to the light source that is correlated with a power of the laser beam emitted from the light source, and
wherein the output control unit performs a feedback control for increasing or decreasing the current value.