NUMERICAL APERTURE (NA) CONTROLLING UNIT, VARIABLE OPTICAL PROBE INCLUDING THE NA CONTROLLING UNIT, AND DEPTH SCANNING METHOD USING THE NA CONTROLLING UNIT

• US 20130070249A1
• Filed: 09/13/2012
• Published: 03/21/2013
• Est. Priority Date: 09/16/2011
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: LEE, Eun-sung, CHOI, Min-seog, LEE, Seung-wan, KIM, Woon-bae, JUNG, Kyu-dong, CHANG, Jong-hyeon
• Granted Patent: US 9,629,552 B2
• Time in Patent Office: Days
• US Class Current: 356/445
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/444 Evaluating skin marks, e.g. mole, nevi, tumour, scar
• CPC Class Codes: G01B 11/22 for measuring depth
• CPC Class Codes: G01B 9/02063 by particular alignment of focus position, e.g. dynamic focussing in optical coherence tomography
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence
• CPC Class Codes: G02B 21/006 focusing arrangements; selection of the plane to be imaged
• CPC Class Codes: G02B 26/005 based on electrowetting
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 3/14 of variable focal length
• CPC Class Codes: G02B 5/005 Diaphragms for cameras G03B9/02

Abstract

A numerical aperture (NA) controlling unit and a variable optical probe including the same are provided. The NA controlling unit includes: an aperture adjustment unit which controls an aperture through which light is transmitted; and a focus control unit that is disposed in a predetermined position with respect to the aperture adjustment unit, that focuses light transmitted through the aperture, and that has an adjustable focal length. The variable optical probe includes: a light transmission unit; a collimator that collimates light transmitted through the light transmission unit into parallel light; an NA controlling unit that focuses light on a sample to be inspected; and a scanner that varies a path of light transmitted through the light transmission unit such that a predetermined region of the sample is scanned by light that passes through the NA controlling unit.

Claims

1. A numerical aperture (NA) controlling unit, comprising:

an aperture adjustment unit that adjusts an aperture through which light propagates; and

a focus control unit that has an adjustable focal length and that is disposed in a predetermined position with respect to the aperture adjustment unit, wherein the focus control unit focuses light which propagates through the aperture.

2. The NA controlling unit of claim 1, wherein the aperture adjustment unit comprises a mechanical diaphragm having an aperture size which is mechanically adjustable.

3. The NA controlling unit of claim 1, wherein the aperture adjustment unit comprises a liquid diaphragm having an aperture size which is adjustable by using hydraulics.

4. The NA controlling unit of claim 1, wherein the aperture adjustment unit comprises a liquid diaphragm having an aperture size which is adjustable by using a microelectrofluid ic method.

5. The NA controlling unit of claim 4, wherein the aperture adjustment unit comprises:

a chamber that forms a space in which a fluid flows;

a first fluid and a second fluid that are accommodated in the chamber, wherein the first fluid is immiscible with the second fluid, and wherein one of the first fluid and the second fluid is formed of a material having a light-transmitting property and an other one of the first fluid and the second fluid is formed of a material having at least one of a light-blocking property and a light-absorbing property; and

an electrode portion that is disposed inside the chamber and in which at least one electrode to which at least one voltage is applied so as to form an electric field in the chamber is arranged,

wherein the aperture through which light propagates is adjustable based on a change of a position of an interface between the first fluid and the second fluid, which change of position is caused by the electric field.

6. The NA controlling unit of claim 5, wherein one of the first fluid and the second fluid comprises one of a liquid metal and a polar liquid, and an other one of the first fluid and the second fluid comprises one of a gas and a non-polar liquid.

7. The NA controlling unit of claim 5, wherein a region of the chamber comprises:

a first channel; and

a second channel that is disposed above the first channel and that is connected to the first channel,

wherein a range of the aperture is defined by a change of a position of a first interface between the first fluid and the second fluid in the first channel and a change of a position of a second interface between the first fluid and the second fluid in the second channel.

8. The NA controlling unit of claim 7, wherein the first channel is formed by a first substrate on which the electrode portion is disposed, a second substrate that is spaced apart from the first substrate and that has a first through hole formed in a central portion of the second substrate and a second through hole formed in a peripheral portion of the second substrate, and a first spacer that is disposed to form an internal space between the first substrate and the second substrate.

9. The NA controlling unit of claim 8, wherein the second channel is formed by the second substrate, a third substrate that is spaced apart from the second substrate, and a second spacer that is disposed to form an internal space between the second substrate and the third substrate.

10. The NA controlling unit of claim 1, wherein the focus control unit comprises a liquid crystal lens having a focal length which is adjustable by applying an electric field gradient to liquid crystals included in the liquid crystal lens to induce a refractive index gradient.

11. The NA controlling unit of claim 1, wherein the focus control unit comprises a liquid lens having a focal length which is adjustable by flowing a fluid on a fluid surface which acts as a lens surface such that a shape of the lens surface is correspondingly adjustable.

12. The NA controlling unit of claim 11, wherein the flowing of the fluid is caused by electrowetting.

13. The NA controlling unit of claim 12, wherein the focus control unit comprises:

a first fluid that has a light-transmitting property and a polar property;

a second fluid that has a light-transmitting property and that is immiscible with the first fluid;

a chamber having an internal space in which the first fluid and the second fluid are accommodated;

a first surface which acts as a first boundary between the first fluid and the second fluid and which forms a lens surface;

a second surface which acts as a second boundary between the first fluid and the second fluid and which induces a change in a curvature of the lens surface;

a first intermediate plate that is disposed in the chamber and that has a first through hole which defines a diameter of a lens corresponding to the lens surface and a second through hole which forms a path traversed by the second fluid; and

an electrode portion that forms an electric field which causes a variation of a position of the second surface.

14. The NA controlling unit of claim 13, wherein the first fluid comprises a polar liquid, and the second fluid comprises one of a gas and a non-polar liquid.

15. The NA controlling unit of claim 11, wherein the flowing of the fluid is caused by pressurization.

16. A depth scanning method for irradiating light by scanning a sample in a depth direction, the method comprising using the numerical aperture controlling unit of claim 1 to vary a focal length and an aperture size simultaneously such that a predetermined numerical aperture is maintained.

17. A variable optical probe comprising:

a light transmission unit;

a collimator that collimates light which propagates via the light transmission unit into parallel light;

the numerical aperture controlling unit of claim 1 that focuses light on a sample to be inspected; and

a scanner that varies a path of light which propagates via the light transmission unit such that a predetermined region of the sample is scanned by light that passes through the numerical aperture controlling unit.

18. The variable optical probe of claim 17, wherein the light transmission unit comprises an optical fiber.

19. The variable optical probe of claim 18, wherein the scanner comprises an actuator that is disposed on one end of the optical fiber and that induces a deformation of the optical fiber to vary the path of the light which propagates via the optical fiber.

20. The variable optical probe of claim 18, wherein the scanner comprises a micro-electromechanical systems (MEMS) scanner that varies the path of the light which propagates via the optical fiber by driving a mirror surface.

21. The variable optical probe of claim 20, wherein the MEMS scanner is disposed between the aperture adjustment unit and the focus control unit.

22. The variable optical probe of claim 21, further comprising a light path conversion member that is disposed between the aperture adjustment unit and the MEMS scanner such that light which passes through the aperture adjustment unit is caused to be incident on the MEMS scanner.

23. The variable optical probe of claim 17, further comprising a lens unit that performs aberration correction on light that passes through the numerical aperture controlling unit.

24. An image diagnosis system comprising:

a light source unit;

the variable optical probe of claim 17 which scans light emitted from the light source unit on tissue to be inspected; and

a detector that detects an image of the tissue by using light reflected from the tissue.

25. A method for detecting an image by using the image diagnosis system of claim 24, comprising:

controlling the numerical aperture controlling unit by using a predetermined numerical aperture value such that light is focused on a tissue surface at a first depth;

scanning a predetermined region of the tissue surface at the first depth and detecting a first image;

controlling the focus control unit such that the focal length of the focus control unit is increased and light is focused on the tissue surface at a second depth, and using the aperture adjustment unit to control a size of the aperture such that the predetermined numerical aperture value is maintained; and

scanning a predetermined region of the tissue surface at the second depth and detecting a second image.

26. An image diagnosis system comprising:

a light source unit that emits light;

an aperture adjustment unit which adjusts an aperture through which light emitted from the light source unit propagates;

a focus control unit that has an adjustable focal length and that is disposed in a predetermined position with respect to the aperture adjustment unit, which focus control unit focuses light which propagates through the aperture on a sample; and

a detector that detects an image of the sample by using light reflected from the sample,

wherein a numerical aperture is controlled by controlling the aperture adjustment unit and the focus control unit, and the image of the sample is detected while a constant distance between the sample and the focus control unit is maintained.

27. The image diagnosis system of claim 26, wherein the aperture adjustment unit comprises at least one of a mechanical diaphragm having an aperture size which is mechanically adjustable, a liquid diaphragm having an aperture size which is adjustable by using hydraulics, and a liquid diaphragm having an aperture size which is adjustable by using a microelectrofluidic method.

28. The image diagnosis system of claim 26, wherein the focus control unit comprises a liquid lens having a focal length which is adjustable by flowing a fluid on a fluid surface which acts as a lens surface such that a shape of the lens surface is correspondingly adjustable.

29. The image diagnosis system of claim 28, wherein the flowing of the fluid is caused by one of electrowetting and pressurization.

30. The image diagnosis system of claim 26, wherein the focus control unit comprises a liquid crystal lens having a focal length which is adjustable by applying an electric field gradient to liquid crystals included in the liquid crystal lens to induce a refractive index gradient.

31. The image diagnosis system of claim 26, further comprising a scanner that scans light emitted from the light source unit in a predetermined horizontal region of the sample.

32. An image diagnosis method comprising:

emitting light from a light source unit;

using a device which focuses light on a predetermined position of a sample by controlling a numerical aperture relating to the device; and

detecting light reflected from the sample.

33. The image diagnosis method of claim 32, further comprising redirecting a path of the light emitted from the light source unit toward the sample and redirecting a path of the light reflected from the sample.

34. The image diagnosis method of claim 32, further comprising modulating the light emitted from the light source unit into a predetermined interference light.

35. The image diagnosis method of claim 34, wherein the modulating of the light emitted from the light source unit into the predetermined interference light comprises redirecting some of the light emitted from the light source unit toward a reference mirror and forming the interference light by using light reflected from the reference mirror.

36. The image diagnosis method of claim 32, further comprising generating an image signal by performing signal processing on a signal detected by the detector.