# US 12,111,240 B2 · Method and system for measuring refractive index of particle sample by using polarization difference of scattered light distribution

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- Number: US 12,111,240 B2
- Document ID: US12111240B2
- Status: Granted
- Kind: B2
- Application number: 17/732,582
- Filed: 2022-04-29
- Published: 2022-08-11
- Granted: 2024-10-08
- Earliest claimed: 2019-11-05
- Assignees: Linkoptik Instruments Co., Ltd.
- Applicants: Linkoptik Instruments Co., Ltd.
- Inventors: Fugen Zhang; Chenyu Zhang
- Web page: https://patentgrep.com/patent/US12111240B2

## CPC

- G01N 15/0211: {Investigating a scatter or diffraction pattern}
- 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)

## Abstract

A method and system for measuring a refractive index of a particle sample by using a polarization difference of scattered light distribution. The method comprises: acquiring a vertically polarized scattered light energy distribution E⊥ and a horizontally polarized scattered light energy distribution E∥, and calculating a scattered light energy distribution polarization difference Ed; according to Mie theory, calculating a vertically polarized scattered light energy matrix (aa) and a scattered light polarization difference matrix (bb) with k×l dimensions under a supposed refractive index value of n(i); calculating a particle size distribution W(i) of a measured particle; acquiring a polarization difference of scattered light distribution (cc); calculating a RMS error σ(j) of Ed and (cc); changing the refractive index value; and repeating the process over and over until finding a refractive index value with the smallest RMS error, wherein the refractive index is the true refractive index of the particle sample.

## Claims

### Claim 1

A system for measuring refractive index of a particle sample by using a polarization difference of scattered light distribution, comprising a laser light source module, a plurality of photoelectric detectors arranged in an array, a processor for receiving and processing electrical signals outputted from the detector, and a memory for storing a processing program;
wherein the laser light source module comprises a linearly polarized laser light source and a light source rotating device, or a linearly polarized light source and a half-wave plate which is arranged at an emitting end of the linearly polarized light source and is capable of being rotated by 45 degrees.

### Claim 2 (depends on 1)

The system for measuring the refractive index of the particle sample by using the polarization difference of the scattered light distribution according to claim 1, wherein the laser light source module comprises an unpolarized laser light source and a polarizer which is arranged at an emitting end of the unpolarized laser light source and is capable of being rotated by 90 degrees.