# US 8,542,362 B2 · Light absorbance measurement method and apparatus

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- Number: US 8,542,362 B2
- Document ID: US8542362B2
- Status: Granted
- Kind: B2
- Application number: 13/011,168
- Filed: 2011-01-21
- Published: 2011-08-11
- Granted: 2013-09-24
- Earliest claimed: 2010-02-05
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Yeong Bae Yeo
- Inventors: Yeong Bae Yeo
- Web page: https://patentgrep.com/patent/US8542362B2

## CPC

- G01N 21/59: Transmissivity (G01N21/25 takes precedence)
- B01L 3/5027: {by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip}
- G01N 21/07: Centrifugal type cuvettes (G01N21/09 takes precedence)
- B01L 3/502738: {characterised by integrated valves (throttle valves in microfluidic sample containers B01L3/502746)}
- B01L 2200/143: Quality control, feedback systems
- B01L 2300/0803: Disc shape
- B01L 2400/0409: centrifugal forces
- B01L 2400/0677: phase change valves; Meltable, freezing, dissolvable plugs; Destructible barriers
- B01L 2400/0688: surface tension valves, capillary stop, capillary break
- 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)
- B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE

## Abstract

Methods and apparatuses for measuring a light absorbance are provided. The method measures light absorbance of at least one detection chamber of a microfluidic device, including the detection chamber and at least one reference chamber. The detection chamber may accommodate a test subject. The method includes detecting a plurality of reference transmitted light intensities for the at least one reference chamber and estimating a value between the plurality of reference transmitted light intensities through nonlinear approximation. The estimated value is then applied to light absorbance measurement of the detection chamber to reduce a light absorbance error of the detection chamber.

## Claims

### Claim 1

A light absorbance measurement apparatus comprising:
a microfluidic device which comprises at least one detection chamber and at least one reference chamber, the at least one detection chamber accommodating a test subject;
at least one light source which emits light to the at least one reference chamber and the detection chamber;
at least one optical detector corresponding to the at least one light source, the optical detector detecting an intensity of light transmitted through the at least one reference chamber and the detection chamber; and
a controller which calculates a plurality of reference transmitted light intensities for the at least one reference chamber, estimates a value between the plurality of reference transmitted light intensities through nonlinear approximation, and applies the estimated value to light absorbance measurement of the detection chamber.

### Claim 2 (depends on 1)

The light absorbance measurement apparatus according to claim 1, wherein the controller calculates the light absorbance as a ratio between a reference transmitted light intensity of the reference chamber and a detection transmitted light intensity of the at least one detection chamber.

### Claim 3 (depends on 1)

The light absorbance measurement apparatus according to claim 1, wherein the at least one light source includes a plurality of light sources and the at least one optical detector includes a plurality of optical detectors, the plurality of light sources and the plurality of optical detectors being provided at positions corresponding to positions of the at least one reference chamber and the at least one detection chamber, and
wherein the controller performs a control operation to turn on one of the plurality of light sources and to turn off the other light sources when transmitted light intensity detection is performed.

### Claim 4 (depends on 3)

The light absorbance measurement apparatus according to claim 3, wherein the at least one reference chamber includes a first reference chamber and a second reference chamber, and
wherein the controller detects the plurality of reference transmitted light intensities in an order such that a reference transmitted light intensity of the first reference chamber is detected, a reference transmitted light intensity of the second reference chamber is detected, a reference transmitted light intensity of the first reference chamber is again detected; and
wherein the controller estimates a value between the detected reference transmitted light intensities through nonlinear approximation.

### Claim 5 (depends on 4)

The light absorbance measurement apparatus according to claim 4, wherein the first reference chamber, the second reference chamber, and the detection chamber are provided in a concentric arrangement on the microfluidic device.

### Claim 6 (depends on 3)

The light absorbance measurement apparatus according to claim 3, wherein the at least one reference chamber includes a first reference chamber, a second reference chamber, and a third reference chamber, and
wherein the controller detects the plurality of reference transmitted light intensities in an order such that a reference transmitted light intensity of the first reference chamber is detected, a reference transmitted light intensity of the second reference chamber is detected, a reference transmitted light intensity of the third reference chamber is detected, a reference transmitted light intensity of the first reference chamber is again detected, and
wherein the controller estimates a value between the detected reference transmitted light intensities through nonlinear approximation.

### Claim 7 (depends on 6)

The light absorbance measurement apparatus according to claim 6, wherein the first reference chamber, the second reference chamber, and the third reference chamber are provided in a concentric arrangement on the microfluidic device.

### Claim 8 (depends on 7)

The light absorbance measurement apparatus according to claim 7, wherein the first reference chamber, the second reference chamber, and the third reference chamber are provided at about equal intervals along a circumferential direction of the microfluidic device.

### Claim 9 (depends on 7)

The light absorbance measurement apparatus according to claim 7, wherein the third reference chamber, the first reference chamber, and the detection chamber are provided in a concentric arrangement on the microfluidic device.

### Claim 10 (depends on 3)

The light absorbance measurement apparatus according to claim 3, wherein the at least one reference chamber includes only a single reference chamber.

### Claim 11 (depends on 10)

The light absorbance measurement apparatus according to claim 10, wherein the controller detects the plurality of reference transmitted light intensities during a plurality of rotation periods of the microfluidic device.