AU5330394A - Confocal microscope and endoscope - Google Patents
Confocal microscope and endoscopeInfo
- Publication number
- AU5330394A AU5330394A AU53303/94A AU5330394A AU5330394A AU 5330394 A AU5330394 A AU 5330394A AU 53303/94 A AU53303/94 A AU 53303/94A AU 5330394 A AU5330394 A AU 5330394A AU 5330394 A AU5330394 A AU 5330394A
- Authority
- AU
- Australia
- Prior art keywords
- light
- optical fibre
- fibre bundle
- optical
- scanning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000013307 optical fiber Substances 0.000 claims description 54
- 239000000835 fiber Substances 0.000 claims description 23
- 230000003287 optical effect Effects 0.000 claims description 22
- 230000037361 pathway Effects 0.000 description 5
- 238000004624 confocal microscopy Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 241001465754 Metazoa Species 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B21/00—Microscopes
- G02B21/0004—Microscopes specially adapted for specific applications
- G02B21/002—Scanning microscopes
- G02B21/0024—Confocal scanning microscopes (CSOMs) or confocal "macroscopes"; Accessories which are not restricted to use with CSOMs, e.g. sample holders
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B21/00—Microscopes
- G02B21/0004—Microscopes specially adapted for specific applications
- G02B21/002—Scanning microscopes
- G02B21/0024—Confocal scanning microscopes (CSOMs) or confocal "macroscopes"; Accessories which are not restricted to use with CSOMs, e.g. sample holders
- G02B21/0028—Confocal scanning microscopes (CSOMs) or confocal "macroscopes"; Accessories which are not restricted to use with CSOMs, e.g. sample holders specially adapted for specific applications, e.g. for endoscopes, ophthalmoscopes, attachments to conventional microscopes
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B21/00—Microscopes
- G02B21/0004—Microscopes specially adapted for specific applications
- G02B21/002—Scanning microscopes
- G02B21/0024—Confocal scanning microscopes (CSOMs) or confocal "macroscopes"; Accessories which are not restricted to use with CSOMs, e.g. sample holders
- G02B21/0036—Scanning details, e.g. scanning stages
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
- G02B23/24—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
- G02B23/26—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes using light guides
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/04—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres
- G02B6/06—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres the relative position of the fibres being the same at both ends, e.g. for transporting images
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
Description
CONFOCAL MICROSCOPE AND ENDOSCOPE
This invention relates to a microscope and more particularly to a microscope using the principal of confocal microscopy.
The principal of confocal microscopy was disclosed in U.S. patent 3,013,467 to Minsky in 1957. With confocal microscopy, a point or spot (which may be diffraction- limited) within an object is illuminated and only light from that point is imaged, e.g. via a pin hole detector. By scanning the spot across a plane (e.g. with a translucent object) a clear image ("optical section") may be obtained.
International patent applications PCT/AU89/00298 and PCT/AU91/00129 describe the design of confocal microscopes which instead of a pin hole (or equivalent) of a conventional confocal microscope use an optical fibre or fibre bundle, thus allowing the distal end to be more freely mobile, transportable and miniaturisable.
The present invention relates to an improvement to confocal microscopes of the type described in the above mentioned International applications and which are particularly suited to produce images inside of the living body of animals or humans.
The invention may be said to reside in a confocal microscope comprising: a light source; an optical fibre bundle for receiving light from the light source and for transmitting the light to an object;
and for allowing light to return from the object through the optical fibre bundle; switching means for selectively switching selected fibres in the optical fibre bundle so as to allow light to selectively be transmitted and returned through respective fibres in the optical fibre bundle; and a detector for receiving returned light from the optical fibre bundle to enable an image of the object to be produced.
The use of switching means which enables the individual fibres in the bundle to be selectively switched to allow light to be transmitted through them enables selected fibres to be switched in sequence so that light is scanned across the focal plane on or within the object and light returning confocally from the object can be detected virtually instantaneously on its return from the object. Another alternative which could be particularly useful for real time imaging of fluorescent objects, is to generate an identical pattern of switching of the switch means which lags the original pattern so that light may be detected confocally a short time after it has illuminated the object. This is because peak fluorescence occurs at a time after illumination of an object.
Preferably the switching means comprises a plurality of switchable optical fibre or waveguide tree couplers, the plurality of tree couplers having a first end which receives light from a first light path and a plurality of second ends which are coupled to or integral with respective fibres of the fibre bundle.
In a further embodiment the switching means comprises a plurality of switches in the respective fibres of the
optical fibre bundle.
In this embodiment of the invention an optical element is provided at an image end of the optical fibre bundle for simultaneously launching light to the individual fibres of the optical fibre bundle and for collecting return light from the optical fibre bundle.
Preferably a beam splitter or directional coupler is disposed proximal to the optical fibre bundle, for receiving light from the light source and transmitting the light to the optical fibre bundle, and for receiving return light from the optical fibre bundle and for transmitting the light to the light detector.
Preferably the first light path comprises one or more optical fibres. However, in other embodiments the first light path could comprise a beam path with or without beam steering optics rather than, or as well as at least one optical fibre.
Preferably a lens element or lens array is provided between the object and the distal end of the optical fibre bundle.
A further aspect of the invention concerns a scanning head which may be used in a confocal microscope.
This aspect of the invention may be said to reside in a scanning head for receiving light from a light source and for transmitting return light to a detector, the scanning head comprising: a scanning means for causing a beam of light to scan an object; a beam steering lens for focussing the light, the
beam steering lens being displaced from an image plane at which the light focuses; and an objective lens for focussing the light on or in an object.
Since this aspect of the invention utilises a beam steering lens which is displaced from the image plane scanning is performed asymmetrically (i.e. so that the lens is proximal to the image plane) thus eliminating detection of lens reflections. Furthermore, the scanning head may be dimensioned to fall within the range for minimum errors in scanning and flatness of field, without introducing added optics to correct for mirror separation.
Preferably a fibre output lens is arranged between the light source and the scanning means for focussing (in combination with the beam steering lens) the light beam at the image plane. The fibre output lens may be a standard microscope objective element, configured for its specific tube length, hence retaining resolution performance.
Preferably the image plane is on the object side of the beam steering lens such that the scanning head is the optical analogue of an eye piece, compatible with standard microscopes.
Preferably the scanning means comprises one or more scanning mirrors. However, in other embodiments other scanning devices such as acousto-optical devices could be utilised.
Preferably at least one optical fibre is provided between the light source and the fibre output lens for transmitting light from the light source to the fibre output lens.
Preferably a beam splitter or directional coupler is provided for directing the light from the light source to the scanning means and for directing return light from the scanning means to the light detector.
Preferred embodiments of the invention will be described, by way of example, with reference to the accompanying drawings in which:
Figure 1 is a view of a first embodiment of the invention;
Figure 2 is a view of the second embodiment of the invention;
Figure 2A is a diagram illustrating control of the embodiments of figures 1 and 2; and Figure 3 is a view of a scanning head according to a further aspect of the invention.
With reference to figure 1 the confocal microscope comprises a light source 10 and a detector 12. The detector 12 may be coupled to a computerised image generator 14 for enabling an image of an object 16 to be formed on a television screen or the like.
The light source 10 is coupled to a beam splitter or directional coupler 18 by a first optical fibre 20 and the light detector 12 is connected to the beam splitter or directional coupler 18 by a second optical fibre 22.
The beam splitter or directional coupler 18 is connected to an array of switched optical fibre or waveguide tree couplers 24. The array of switched tree couplers 24 comprises a first tree coupler 24 ' which has a first end 24a and a plurality of branches 24b which have second ends 24c. Thus, the first tree coupler 24' has one fibre or
connection in and "n" fibres or connections out. The first tree coupler may then be linked to a plurality of further tree couplers 24 ' ' and if necessary the second ends of the further tree couplers 24 ' ' may be yet connected to further tree couplers until the number of outputs from the array of tree couplers can be linked to (or form an integral part of) respective fibres in an optical fibre bundle 30 which includes a plurality of individual optical fibres (not shown) . Thus, each individual optical fibre is connected to the output end of the array of tree couplers 24.
The tree couplers are switchable to enable light to pass through selected branches of the optical fibre or waveguide tree couplers so that light can be launched into selected individual optical fibres in the optical fibre bundle 30.
A lens or lens array 32 is arranged at the distal or object end of the optical fibre bundle 30 for focussing the light transmitted through the optical fibre bundle on or in the object 16. The return light from the object 16 which returns confocally from the object 16 may traverse the same pathway, as far as the beam splitter or directional coupler 18. The beam splitter or directional coupler 18 then directs the beam through the second optical fibre 22 to the light detector 12 for formation of an image of the object.
The image is generated by the light detector 12 and image generator 14 by switching the tree couplers 24' , 24' ' in such a way that light is scanned across the focal plane on or within the object 16. Light returning confocally from the object can be detected virtually instantaneously after it has traversed the same pathway, as far as the beam splitter 18, on its return from the object or alternatively, an identical pattern of switching in the
tree couplers 24', 24'' can be generated which lags the original pattern so that light may be detected confocally a short time after it has illuminated the object. This technique is useful in real-time imaging of fluorescence objects because peak fluorescence occurs at a finite time after illumination of an object.
The light emerging from the distal end of the fibre bundle 30 may be diffraction limited.
In an alternative arrangement to that shown in figure 1, the optical fibres 20 or 22 could be replaced by a path with or without beam steering optics to form the first light path instead of using optical fibres.
Figure 2 shows a second embodiment of the invention in which like elements are represented by the same reference numerals to those in figure 1. In this embodiment of the invention the optical fibre bundle 30 is provided with fibre on-off switches 34 in the individual fibres of the optical fibre bundle so that the switches are effectively integral with the individual fibres in the bundle thereby doing away with the need for an array of switched tree couplers. Optical elements 36 such as lenses or the like may be provided at the proximal end of the optical fibre bundle 30 to simultaneously launch light into the individual optical fibres of the optical fibre bundle 30 which is received from the beam splitter or directional coupler 18.
The in-fibre on-off switches 34 may be optical, optoacoustic or electro-optic or other type of switches which either prevent, preferably with minimal reflection, or allow light to pass down a particular fibre. An example
of in-fibre switching is given by Lytel-R. (1990) "Applications of Electro-optic Polymers to Integrated Optics", S.P.I.E., 1216, 30.
By means of in-fibre switching, at any one moment in time, light is allowed to pass down one or even several fibres of the bundle. As in figure 1, after light emerges from the distal end of a fibre in the optical fibre bundle 30 it is focussed on a point or spot on or within the object 16 and light returning confocally from the object may traverse the same pathway, as far as the beam splitter or directional coupler 18. By an appropriate pattern of switching within the bundle 30, scanning of light across the focal plane of the object may be achieved. The light may return from the object by the same path almost instantaneously or, as described above, the in-fibre switching may lag the original switching pattern.
Because the resolution of the image will be limited by the gaps between the individual fibres in the optical fibre bundles 30, in figures 1 and 2 improved resolution may be obtained by movements (which could, for example, be quite small - e.g. of a similar magnitude as the distance between the adjacent fibres in the bundle) of the distal end of the optical fibre bundles 30 in relation to the object 16.
This would allow scanning in the focal plane of the object to be less discrete and more continuous in nature. The movement could be either of the fibre bundle tip or of the object or of both.
As is shown in figure 2A, three optical fibres 30a, 30b and 30c of the optical fibre bundle 30 which including a optical, optoacoustic, electro-optic or other type of switch 31 which are electrically, optically or otherwise
connected to a controller 33 (such as a computer or the like) for example by leads or connectors 35. Alternatively the controller could control optical switches by sending light to those switches (eg through the fibre optic bundle or array of tree couplers) . The controller 33 applies output signals to the switches 31 to control the switches so that the switches either allow or prevent light to pass through the optical fibre 30a, 30b and 30c. A similar arrangement to that shown above may be used to control the switchable optical fibre or waveguide tree couplers described with reference to figure 1. Alternatively switchable waveguide tree couplers could form part of an integrated chip with optical and electronic components.
Figure 3 discloses a scanning head which is particularly useful in non-endoscopic applications of the microscope.
In figure 3 the scanning head comprises a head 42 which contains one or more scanning mirrors 44 and a fibre output lens 46 which receives light from an optical fibre or point source 48. The optical fibre or point source 48 is coupled to a beam splitter or directional coupler 50 which in turn is coupled to a light source 52 and light detector 54 by individual optical pathways or waveguides (such as optical fibres) 56 and 58.
The head 42 includes a beam steering lens 60. The beam steering lens 60 is displaced axially from an image plane of the lens 62 so that scanning is performed asymmetrically (i.e. so that the lens 60 is proximal to the image plane) thus eliminating detection of lens reflections. A microscope objective lens 62 is provided for focussing the light from the light source 52 on or in an object.
Return light from the object is returned along the same path as the incident light as far as beam splitter 50 and is directed by beam splitter 50 to light detector 54 via pathway 58 for formation of an image.
Since the scanning head performs scanning asymmetrically in relation to the beam steering lens 60 problems inherent in symmetrical designs in which there may be problems of confocal return from the lens and aberrations due to the lens elements being at suboptimal separations are eliminated.
The fibre output lens 46 is a standard microscope objective element, configured for its specified tube length, hence retaining resolution performance. The image is projected below the beam steering lens such that the scanning head is the optical analogue of an eyepiece, compatible with standard microscopes. The dimensions achieved fall within the range of minimum errors in scanning and flatness of field, without introducing added optics to correct for minor separation.
Since modifications within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiment described by way of example hereinabove.
Claims (13)
1. A confocal microscope comprising: a light source; an optical fibre bundle for receiving light from the light source and for transmitting the light to an object; and for allowing light to return from the object through the optical fibre bundle; switching means for selectively switching selected fibres in the optical fibre bundle so as to allow light to selectively be transmitted and returned through respective fibres in the optical fibre bundle; and a detector for receiving returned light from the optical fibre bundle to enable an image of the object to be produced.
2. The microscope of claim 1 wherein the switching means comprises a plurality of switchable optical fibre or waveguide tree couplers, the plurality of tree couplers having a first end which receives light from a first light path and a plurality of second ends which are coupled to or integral with respective fibres of the fibre bundle.
3. The microscope of claim 1 wherein the switching means comprises a plurality of switches in the respective fibres of the optical fibre bundle.
4. The microscope of claim 3 wherein an optical element is provided at an image end of the optical fibre bundle for simultaneously launching light to the individual fibres of the optical fibre bundle and for collecting return light from the optical fibre bundle.
5. The microscope of claim 1 wherein a beam splitter or directional coupler is disposed proximal to the optical fibre bundle, for receiving light from the light source and transmitting the light to the optical fibre bundle, and for receiving return light from the optical fibre bundle and for transmitting the light to the light detector.
6. The microscope of claim 1 wherein the first light path comprises one or more optical fibres.
7. The microscope of claim 1 wherein a lens element or lens array is provided between the object and the distal end of the optical fibre bundle.
8. A scanning head for receiving light from a light source and for transmitting return light to a detector, the scanning head comprising: a scanning means for causing a beam of light to scan an object; a beam steering lens for focussing the light, the beam steering lens being displaced from an image plane at which the light focuses; and an objective lens for focussing the light on or in an object.
9. The scanning head of claim 8 wherein a fibre output lens is arranged between the light source and the scanning means for focussing, in combination with the beam steering lens, the light beam at the image plane.
10. The scanning head of claim 8 wherein the image plane is on the object side of the beam steering lens such that the scanning head is the optical analogue of an eye piece, compatible with standard microscopes.
11. The scanning head of claim 8 wherein the scanning means comprises one or more scanning mirrors. However, in other embodiments other scanning devices such as acousto- optical devices could be utilised.
12. The scanning head of claim 8 wherein at least one optical fibre is provided between the light source and the fibre output lens for transmitting light from the light source to the fibre output lens.
13. The scanning head of claim 8 wherein a beam splitter or directional coupler is provided for directing the light from the light source to the scanning means and for directing return light from the scanning means to the light detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU53303/94A AU669760B2 (en) | 1992-10-23 | 1993-10-19 | Confocal microscope and endoscope |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPL5462 | 1992-10-23 | ||
| AUPL546292 | 1992-10-23 | ||
| AU53303/94A AU669760B2 (en) | 1992-10-23 | 1993-10-19 | Confocal microscope and endoscope |
| PCT/AU1993/000534 WO1994010595A1 (en) | 1992-10-23 | 1993-10-19 | Confocal microscope and endoscope |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU5330394A true AU5330394A (en) | 1994-05-24 |
| AU669760B2 AU669760B2 (en) | 1996-06-20 |
Family
ID=25630036
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU53303/94A Ceased AU669760B2 (en) | 1992-10-23 | 1993-10-19 | Confocal microscope and endoscope |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU669760B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999004301A1 (en) * | 1997-07-16 | 1999-01-28 | Optiscan Pty. Ltd. | Scanning microscope with miniature head |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0339061B1 (en) * | 1987-09-24 | 1995-03-29 | Washington University | Kit for converting a standard microscope into, and design for, a single aperture confocal scanning epi-illumination microscope |
| DE68929464T2 (en) * | 1988-07-13 | 2003-11-20 | Optiscan Pty Ltd | scanning microscope |
| ATE126903T1 (en) * | 1990-04-06 | 1995-09-15 | Martin Russell Harris | CONFOCAL MICROSCOPE. |
-
1993
- 1993-10-19 AU AU53303/94A patent/AU669760B2/en not_active Ceased
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999004301A1 (en) * | 1997-07-16 | 1999-01-28 | Optiscan Pty. Ltd. | Scanning microscope with miniature head |
| GB2340332A (en) * | 1997-07-16 | 2000-02-16 | Optiscan Pty Ltd | Scanning microscope with miniature head |
| GB2340332B (en) * | 1997-07-16 | 2001-05-30 | Optiscan Pty Ltd | Scanning microscope with miniature head |
Also Published As
| Publication number | Publication date |
|---|---|
| AU669760B2 (en) | 1996-06-20 |
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