Endoscope with optical fiber and fiber optics system
View Patent ↗An endoscope has an optical fiber and at least one photo-detector. The optical fiber has a core that transmits illuminating light and at least one cladding that surrounds the core and transmits reflected light. The cladding has a refraction slope surface that is tapered toward a direction opposite the tip portion of the optical fiber. The photo-detector detects the reflected light that exits from the refraction slope surface by refraction.
1. An endoscope, comprising:
an optical fiber having a core that transmits illuminating light and at least one cladding that surrounds the core, the cladding transmitting reflected light;
at least one photo-detector that detects the reflected light,
the cladding comprising a refraction slope surface that is tapered toward a direction of a proximal end of the optical fiber, the photo-detector detecting reflected light that exits from the refraction slope surface; and
an actuator that vibrates a tip portion of the optical fiber so as to scan the illuminating light over an observed portion, the tip portion being defined at a front end of the endoscope, and
the refraction slope surface being formed at a portion of the optical fiber so as to be positioned rearward of the actuator with respect to the front end of the endoscope.
2. The endoscope according to claim 1 , further comprising a resin surrounding the refraction slope surface, the resin having a refractive index higher than a refractive index of the cladding.
3. The endoscope according to claim 2 , wherein the resin comprises polymethyl methacrylate (PMMA).
4. The endoscope according to claim 2 , wherein the resin is transparent.
5. The endoscope according to claim 2 , wherein the refractive index of the resin is defined such that the reflected light exiting from the refraction slope surface progresses toward the photo-detector.
6. The endoscope according to claim 1 , wherein the optical fiber comprises a single-mode optical fiber.
7. The endoscope according to claim 1 , wherein the optical fiber comprises a single-cladding optical fiber.
8. The endoscope according to claim 1 , wherein the optical fiber comprises a double-cladding optical fiber.
9. The endoscope according to claim 1 , wherein the actuator comprises a tubular piezoelectric actuator.
10. The endoscope according to claim 1 , wherein the refraction slope surface is formed at a portion of the optical fiber adjacent to a proximal end of the endoscope.
11. The endoscope according to claim 1 , wherein the photo-detector comprises a photodiode.
12. The endoscope according to claim 1 , wherein the photo-detector is positioned such that a photo-receiving area of the photo-detector faces in a direction along a longitudinal axis of the optical fiber.
13. The endoscope according to claim 12 , further comprising a glass lens that is positioned in front of the photo-receiving area and refracts the reflected light toward the photo-receiving area.
14. The endoscope according to claim 1 , wherein the photo-detector is oriented at an angle relative to a longitudinal axis of the optical fiber so as to face the refraction slope surface.
15. The endoscope according to claim 1 , wherein a plurality of photo-detectors are positioned laterally with respect to the optical fiber.
16. The endoscope according to claim 1 , wherein an angle of the refraction slope surface relative to a longitudinal axis of optical fiber is defined such that the reflected light exiting from the refraction slope surface progresses toward the photo-detector.
17. The endoscope according to claim 1 , wherein the refraction slope surface is positioned symmetrical with respect to a center axis of the optical fiber.
18. The endoscope according to claim 1 , wherein the cladding further comprises an attenuation slope surface opposing the refraction slope surface.
19. The endoscope according to claim 18 , further comprising a shield member that covers the attenuation slope surface.
20. The endoscope according to claim 1 , wherein the refraction slope surface comprises a conical surface.
21. The endoscope according to claim 1 , wherein the refraction slope surface is formed by etching the cladding.
22. An endoscope tip portion, comprising:
an actuator that vibrates a tip portion of an optical fiber so as to scan illuminating light exiting from the tip portion over an observed portion, the tip portion being defined at a front end of the endoscope, the optical fiber having a core that transmits the illuminating light and at least one cladding that surrounds the core, and the cladding transmitting reflected light; and
at least one photo-detector that detects the reflected light,
the cladding comprises a refraction slope surface that is tapered toward a direction of a proximal end of the optical fiber, the photo-detector detecting reflected light that exits from the refraction slope surface, and the refraction slope surface being formed at a portion of the optical fiber so as to be positioned rearward of the actuator with respect to the front end of the endoscope.
23. An endoscope system, comprising:
a light source that emits illuminating light;
an optical fiber having a core that transmits the illuminating light and at least one cladding that surrounds the core, the cladding transmitting reflected light;
at least one photo-detector that detects the reflected light,
wherein the cladding comprises a refraction slope surface that is tapered toward a direction of a proximal end of the optical fiber, the photo-detector detecting reflected light that exits from the refraction slope surface; and
an actuator that vibrates a tip portion of the optical fiber so as to scan the illuminating light over an observed portion, the tip portion being defined at a front end of the endoscope, and
the refraction slope surface being formed at a portion of the optical fiber so as to be positioned rearward of the actuator with respect to the front end of the endoscope.