Spectrally encoded forward view and spectrally encoded multi-view endoscope using back-reflected light between reflective surfaces

Patent metadata

Field	Value
Publication number	US-10682044-B2
Application number	US-201816476826-A
Country	US
Kind code	B2
Filing date	Jan 10, 2018
Priority date	Jan 12, 2017
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

A Spectrally Encoded Forward View or Multi-View Endoscope, Probe, and Imaging Apparatus and system, and methods and storage mediums for use therewith, are provided herein. At least one apparatus or system may comprise a first waveguide; an optical system; and a diffraction grating. The first waveguide may be for guiding light from a light source to an output port of the first waveguide. The optical system may comprise at least a first reflecting surface and a second reflecting surface. The first reflecting surface may be arranged to reflect light from the output port of the first waveguide to the second reflecting surface. The second reflecting surface may be arranged to reflect light from the first reflecting surface back through the first reflecting surface to the diffraction grating. The diffraction grating may diffract light from the second reflecting surface in several lights/colors of non-zero diffraction orders in a first direction.

First claim

What is claimed is:

1. An endoscope comprising:
a first waveguide for guiding light from a light source to an output port of the first waveguide;
an optical system comprising at least a first reflecting surface and a second reflecting surface; and
a diffraction grating;
wherein the first reflecting surface is arranged to reflect light from the output port of the first waveguide to the second reflecting surface;
wherein the second reflecting surface is arranged to reflect light from the first reflecting surface back through the first reflecting surface to the diffraction grating; and
wherein the diffraction grating diffracts light from the second reflecting surface in a non-zero diffraction order in a first direction.

2. The endoscope according to claim 1 , wherein the first reflecting surface is a total internal reflecting surface for at least a portion of light that the first reflecting surface receives from the output port of the first waveguide.

3. The endoscope according to claim 1 , wherein the first reflecting surface and a portion of the diffraction grating component are on the same plane and are both on a single support structure.

4. The endoscope according to claim 1 , wherein the second reflecting surface is a curved surface.

5. The endoscope according to claim 1 , wherein the optical system further comprises a spacer located between the output port of the first waveguide and the first reflecting surface.

6. The endoscope according to claim 5 , wherein the spacer includes a GRIN lens.

7. The endoscope according to claim 6 , wherein an optical axis of the first waveguide is co-linear with an optical axis of the GRIN lens.

8. The endoscope according to claim 1 , wherein:
an end portion of the endoscope is between the output port of the first waveguide and an illumination surface;
the illumination surface is a final surface of the endoscope out of which illumination light exits the endoscope; and
a diameter of an end portion of the endoscope is less than 350 pm.

9. The endoscope according to claim 1 , wherein the endoscope has a plurality of propagation modes, wherein:
in a first propagation mode among the plurality of propagation modes, light from the output port of the first waveguide is reflected by the first reflecting surface, then reflected by the second reflecting surface, and is then diffracted by the diffraction grating; and
in a second propagation mode among the plurality of propagation modes, light from the output port of the first waveguide is diffracted by the diffraction grating and is not reflected by the first reflecting surface or the second reflecting surface.

10. The endoscope according to claim 9 , further comprising a detector and a switch.

11. The endoscope according to claim 1 , wherein:
the first reflecting surface is configured to receive light from the output port at a first angle with respect to a normal of the first reflecting surface; and
the first angle is greater than a critical angle for total internal reflection.

12. The endoscope according to claim 1 , wherein the first reflecting surface and the diffraction grating component are on substantially parallel planes.

13. The endoscope according to claim 12 , wherein the first reflecting surface is an interface between a single support structure and a thin film or layer and the diffraction grating is on the thin film or layer.

14. The endoscope according to claim 1 , wherein the second reflecting surface is a surface of a ball lens.

15. The endoscope according to claim 1 , wherein:
the endoscope is a color endoscope; and
the diffraction grating diffracts light from the second reflecting surface in blue, green and red wavelength lights of non-zero diffraction orders, which are mutually different in the diffraction order, in the first direction.

16. The endoscope according to claim 15 , wherein the optical system further comprises a spacer including a GRIN lens, the spacer being located between the output port of the first waveguide and the first reflecting surface, and a light exiting end of the GRIN lens is inclined in a predetermined direction so that the first reflecting surface is a total internal reflecting surface.

17. The endoscope according to claim 15 , wherein a gap between a rotation center of an end portion of the endoscope and a center of the light beam exiting from the diffraction grating is less than 1/10 of the diameter of the circle circumscribing the end portion of the endoscope.

18. The endoscope according to claim 15 , wherein the first reflecting surface is an interface between a single support structure and a thin layer and the diffraction grating is on the thin layer, and the refractive index N 1 of the support structure and the refractive index N 2 of the thin layer satisfy N 2 /N 1 <0.8.

19. The endoscope according to claim 18 , wherein the thin layer is an air gap and the refractive index N 2 of the thin layer satisfies N 2 =1.

20. The endoscope according to claim 19 , wherein the diffraction grating is supported by a cover glass.

21. The endoscope according to claim 18 , wherein a forming member of the diffraction grating also serves as the thin layer.

22. An imaging apparatus comprising:
a light source;
a detector;
a first waveguide for guiding light from the light source to an output port of the first waveguide;
an optical system comprising at least a first reflecting surface and a second reflecting surface;
a diffraction grating;
wherein the first reflecting surface is arranged to reflect light from the output port of the first waveguide to the second reflecting surface;
wherein the second reflecting surface is arranged to reflect light from the first reflecting surface back through the first reflecting surface to the diffraction grating;
wherein the diffraction grating diffracts light from the second reflecting surface in a non-zero diffraction order in a first direction; and

a second waveguide for gathering light and sending the gathered light to the detector.

23. A probe comprising:
a first waveguide; and
an optical system comprising at least:
a first reflecting surface;
a second reflecting surface; and
a diffraction grating;

wherein the diffraction grating receives light and is arranged to diffract the received light through the first reflecting surface;
wherein the second reflecting surface is arranged to receive diffracted light which passed through the first reflecting surface that was diffracted by the diffraction grating and reflect the diffracted light back towards the first reflecting surface;
wherein the first reflected surface is arranged to reflect the diffracted light from the second reflecting surface towards the first waveguide; and
wherein the first waveguide is arranged to receive the diffracted light that the first reflecting surface reflects from the second reflecting surface.

24. The probe according to claim 23 , wherein:
the first reflecting surface is configured to receive light from the second reflecting surface at a first angle with respect to a normal of the first reflecting surface; and
the first angle is greater than a critical angle for total internal reflection.

25. The probe according to claim 23 , wherein the first reflecting surface and the diffraction grating component are on substantially parallel planes.

26. The endoscope according to claim 1 , wherein the diffraction grating defines a fir

Assignees

• Canon Usa Inc

Inventors

• Wu Tzu-Yu
• Ikuta Mitsuhiro
• Takeuchi Seiji
• Kohara Naoki
• Koyama Osamu

Classifications

• A61B1/0625

  for multiple fixed illumination angles · CPC title

• A61B1/0627

  for variable illumination angles · CPC title

• A61B1/00181 Primary

  for multiple fixed viewing angles (A61B1/00193 takes precedence) · CPC title

• G02B3/0087

  with index gradient · CPC title

• G01J3/0218

  using optical fibers · CPC title