Determining a flow characteristic of an object being movable in an element

Patent metadata

Field	Value
Publication number	US-9091573-B2
Application number	US-201214117635-A
Country	US
Kind code	B2
Filing date	May 22, 2012
Priority date	Jun 1, 2011
Publication date	Jul 28, 2015
Grant date	Jul 28, 2015

Abstract

A sensor device ( 340 ) for determining a flow characteristic of an object ( 341 ) being movable in an element ( 342 ) comprises a light emitting unit ( 344 ) configured for emitting light towards the element ( 342 ) and a light detecting unit ( 344 ) configured for detecting light scattered back from the element ( 342 ). The sensor device ( 340 ) comprises an optical unit ( 346 ) configured for spatially separating a light incidence element portion ( 348 ) of the element ( 342 ) and a light detection element portion ( 350 ) of the element ( 342 ) from one another, wherein the light incidence element portion ( 348 ) is associated with the emitted light inciding on the element ( 342 ) and the light detection element portion ( 350 ) is associated with the back-scattered light scattered back from the element ( 342 ) for detection. The sensor device ( 340 ) comprises a determining unit ( 358 ) configured for determining the flow characteristic of the object ( 341 ) being movable in the element ( 342 ) based on light indicative of the emitted light and the detected back-scattered light. The sensor device ( 340 ) allows for an accurate and easy determination of the flow characteristic of the object ( 341 ).

First claim

The invention claimed is:

1. A sensor device for determining a flow characteristic of an object being movable in an element, the sensor device comprising:
a light emitting unit configured for emitting light towards the element,
a light detecting unit configured for detecting light scattered back from the element,
an optical structure including a light incidence lens portion and a light detection lens portion, the light incidence lens portion and the light detection lens portion being displaced from one another, wherein the light incidence lens portion is configured to emit light incident on the a first portion of the element and the light detection lens portion is configured to receive back-scattered light which is scattered back from a second portion of the element for detection, the first and second element portions being separated from each other, wherein the optical structure blocks any back-scattered light received by the light incident lens portion, and
a unit configured for receiving light indicative of the emitted light and the detected back-scattered light such that the flow charactistics of the moveable object are determinable by self-mixing interferometry.

2. The sensor device according to claim 1 , wherein the light emitting unit and the light detecting unit are integrally formed.

3. The sensor device according to claim 1 , wherein the optical unit comprises a light path separation element configured for separating a light path of the emitted light towards the light incidence element portion from a light path of the back-scattered light scattered back from the light detection element portion.

4. The sensor device according to claim 3 , wherein the light path separation element is configured as a polarizing beam splitter, wherein a polarization direction of the emitted light emitted by the light emitting unit is oriented under an angle of 45 degrees with respect to a polarization axis of the polarizing beam splitter.

5. The sensor device according to claim 3 , wherein the optical unit comprises a light redirecting element configured for redirecting the emitted light received from the light path separation element towards the light incidence element portion.

6. The sensor device according to claim 5 , wherein a distance between the light incidence element portion and the light detection element portion is adjustable by a relative arrangement of the light path separation element and the light redirecting element.

7. The sensor device according to claim 1 , the sensor device further comprising:
a polarization alternation element arranged between the optical unit and the element, wherein the polarization alternation element is configured for altering a polarization of the emitted light received from the optical unit and a polarization of the back-scattered light scattered back from the element.

8. The sensor device according to claim 7 , wherein the optical unit and the polarization alternation element are configured and are arranged relative to one another such that a polarization of the back-scattered light detected by the light detecting unit and a polarization of the light indicative of the emitted light are orthogonal to one another.

9. The sensor device according to claim 1 , the sensor device further comprising:
a first lens arranged between the optical unit and the light incidence element portion, wherein the first lens is configured for focusing the emitted light towards the light incidence element portion, and/or
a second lens arranged between the optical unit and the light detection element portion, wherein the second lens is configured for focusing the back-scattered light scattered back from the light detection element portion.

10. The sensor device according to claim 1 , the sensor device further comprising:
a first optical fiber arranged between the optical unit and the light incidence element portion, wherein the first optical fiber is configured for directing the emitted light from the optical unit towards the light incidence element portion, and/or
a second optical fiber arranged between the optical unit and the light detection element portion, wherein the second optical fiber is configured for directing the back-scattered light from the light detection element portion to the optical unit.

11. The sensor device according to claim 1 , the sensor device further comprising:
a third lens arranged between the light detecting unit and the optical unit, wherein the third lens is configured for focusing the back-scattered light towards the light detecting unit.

12. The sensor device according to claim 1 , wherein the flow characteristic of the object comprises at least one of a flow velocity of the object and a flow direction of the object, and/or wherein the object comprises a blood cell and the element comprises a skin.

13. A method of determining a flow characteristic of an object being movable in an element, the method comprising:
emitting light towards the element by a light source,
detecting light scattered back from the element by a light detector, and
receiving light indicative of the emitted light and the detected back-scattered light with a unit to enable the flow characteristics of the moveable object to be determined by self-mixing interferometry,
wherein a light incidence element portion of the element and a light detection element portion of the element are spatially separated from one another by an optical structure, wherein the optical structure channels emitted light from the light source to the light incidence element portion, channels backscattered light from the light detection element portion to the receiving unit, and prevents back-scattered light from the incident element portion from reaching the determining unit.

14. The method of claim 13 , further comprising:
separating a light path of the emitted light towards the light incidence element portion from a light path of the back-scattered light scattered back from the light detection element portion with a light path separation element.

15. The method of claim 14 , further comprising:
redirecting the emitted light received from the light path separation element towards the light incidence element portion with a light redirecting element; and
adjusting a distance between the light incidence element portion and the light detection element portion by a relative arrangement of the light path separation element and the light redirecting element.

16. The method of claim 13 , further comprising:
altering a polarization of the emitted light received from the optical device and a polarization of the back-scattered light scattered back from the element with a polarization alternation element.

17. A sensor device for determining a flow characteristic of blood flowing in skin, the sensor device comprising:
a light source;
an optical element including:
a light path separation element,
a first optical element portion extending from adjacent the light source to the light path separation element,
a second optical element portion extending from the light path separation element to a light output end adjacent an incident light region of the skin to receive incident light from the light source,
a third optical element portion extending from a light receiving end adjacent another region of the skin displaced from the incident light region of the skin to receive backscattered light from the another region of the skin to convey the reeived backscattered light to the light path separation element;

wherein the light separation element is configured to:
pass light from the first opt

Assignees

• Van Der Lee Alexander Marc
• Veen Jeroen
• Koninkl Philips Nv

Inventors

• Van Der Lee Alexander Marc
• Veen Jeroen

Classifications

• G01S7/4917

  superposing optical signals in a photodetector, e.g. optical heterodyne detection · CPC title

• G01F1/00 Primary

  Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow (measuring a proportion of the volume flow G01F5/00) · CPC title

• G01S17/88

  Lidar systems specially adapted for specific applications · CPC title

• G01N21/53

  within a flowing fluid, e.g. smoke · CPC title

• A61B5/6801

  specially adapted to be attached to or worn on the body surface · CPC title