Optical fiber scanning probe
Optical probes are provided for miniature applications, e.g. medical inspections and procedures or in industrial inspections. The probe comprises an optical guide, a first lens system mounted on a distal end portion of the optical guide for focusing light from the optical guide, an actuator for displacing the distal end portion and the first lens system to enable optical scanning, and a second lens system fixed inside the probe to receive radiation from the first lens system. The second lens system is selected to enable a deflection of radiation from the first lens system in a direction corresponding to a direction of displacement of the first lens system by the actuator. The second lens system can be a cheap negative lens, and the invention is thereby particularly useful for increasing the field of view (FOV) of cheap, disposable optical probes.
1. A scanning optical probe ( 1 ) comprising:
a housing ( 3 ),
an optical guide ( 2 ) with a distal end portion ( 2 a ) inside the housing,
a first lens system ( 4 ) rigidly coupled to said distal end portion,
actuation means ( 6 , 7 ) capable of displacing said distal end portion and the first lens system to enable optical scanning of a region of interest (ROI) at a distal end of the housing, and
a second lens system ( 9 ) fixed inside the distal end of the housing to receive radiation from the first lens system,
wherein the first lens system is selected to enable focusing of light from the optical guide at the region of interest, and wherein the second lens system is selected to enable a deflection of the focused light from the first lens system in a direction corresponding to a direction of displacement of the first lens system by the actuation means.
2. The scanning optical probe according to claim 1 , wherein the optical guide defines a center axis of the scanning of the first lens system displaced by the actuation means, and wherein the second lens system is selected to deflect the focused light from the first lens system further away from the center axis, when the first lens system is displaced away from the center axis.
3. The scanning optical probe according to claim 1 , wherein the second lens system is a negative lens system with optical power D 2 <0.
4. The scanning optical probe according to claim 3 , wherein the first lens system has an optical power D 1 , and wherein a ratio D 2 /D 1 fulfill D 2 /D 1 <0.1.
5. The scanning optical probe according to claim 4 , wherein D 2 /D 1 <−0.25.
6. The scanning optical probe according to claim 1 , wherein the combined first and the second lens system has an optical power D tot and the second lens system is positioned a distance Q from an object plane of the probe, and wherein |QD tot |>0.5.
7. The scanning optical probe according to claim 1 , wherein the second lens system ( 9 ) comprises an aspherical lens.
8. The scanning optical probe according to claim 1 , wherein the second lens system ( 9 ) is formed in polycarbonate.
9. The scanning optical probe according to claim 1 , wherein the second lens system ( 9 ) is a biconcave lens.
10. The scanning optical probe according to claim 1 , wherein the second lens system also forms a transparent window ( 8 ) at the distal end of the housing.
11. The scanning optical probe according to claim 1 , wherein the housing ( 3 ) comprises at its distal end a transparent window ( 8 ), the transparent window having an insignificant optical power as compared to the optical power of the first ( 4 ) and second lens systems ( 9 ).
12. The scanning optical probe according to claim 1 , wherein the probe forms part of an endoscope, a catheter, a needle, or a biopsy needle.
13. An optical imaging system ( 100 ), the system comprising
the scanning optical probe ( 1 ) according to claim 1 , and
an imaging detector (ID) optically coupled to said optical probe ( 1 ) for receiving radiation from a region of interest through the optical probe and forming an image.