Optical coherence tomographic apparatus

Patent metadata

Field	Value
Publication number	US-10028656-B2
Application number	US-201615014136-A
Country	US
Kind code	B2
Filing date	Feb 3, 2016
Priority date	Jan 26, 2012
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

An optical coherence tomographic apparatus which obtains a tomographic image of an object based on light obtained by combining return light from the object irradiated with measurement light through a first lens and reference light corresponding to the measurement light, the apparatus comprises a scanning unit provided on an optical path of the measurement light and configured to scan the measurement light on the object; a second lens disposed between the scanning unit and the object; an optical path branching unit disposed between the first lens and the second lens and configured to make the optical path of the measurement light branch off to an observation optical path for observation of the object; a dividing unit that splits light emitted from a light source into the measurement light and the reference light; and a focus lens disposed between the dividing and scanning units.

First claim

What is claimed is:

1. An optical coherence tomographic apparatus which obtains a tomographic image of a fundus of an eye to be examined based on light obtained by combining return light from the fundus irradiated with measurement light through a first lens and reference light corresponding to the measurement light, the apparatus comprising:
first and second scanning units configured to be provided on an optical path of the measurement light and configured to scan the measurement light on the fundus in directions crossing each other;
a second lens configured to be disposed between said first and second scanning units and the first lens on the optical path of the measurement light;
a first dichroic mirror configured to be disposed between the first lens and said second lens and configured to make the optical path of the measurement light branch off to an optical path of a fundus observation optical system for observation of the fundus, by separating light having a wavelength different from a wavelength of the measurement light;
third and fourth scanning units configured to be disposed on the optical path of the fundus observation optical system and configured to scan light for observation of the fundus on the fundus in directions crossing each other; and
a third lens configured to be disposed on the optical path of the fundus observation optical system and configured to be disposed between said third and fourth scanning units and said first dichroic mirror,
wherein said second lens and said first and second scanning units are disposed such that a position between said first and second scanning units is conjugate to an anterior ocular segment of the eye,
wherein said third lens and said third and fourth scanning units are disposed such that a position between said third and fourth scanning units is conjugate to the anterior ocular segment,
wherein the optical path of the fundus observation optical system is disposed on a reflection optical path of said first dichroic mirror,
wherein the optical path of the measurement light is disposed on a transmission optical path of said first dichroic mirror,
wherein the apparatus further comprises a second dichroic mirror configured to be disposed between the first lens and said second lens and configured to make the optical path of the measurement light branch off to an optical path of an anterior eye observation optical system for observation of an anterior ocular segment of the eye, by separating light having a wavelength different from a wavelength of the measurement light,
wherein said second dichroic mirror is disposed at the first lens side with respect to said first dichroic mirror,
wherein the optical path of the anterior eye observation optical system is disposed on a transmission optical path of said second dichroic mirror, and
wherein the optical path of the fundus observation optical system and the optical path of the measurement light are disposed on a reflection optical path of said second dichroic mirror.

2. The apparatus according to claim 1 , wherein the shape and material of said second lens are the same as those of said third lens.

3. The apparatus according to claim 1 , wherein said second lens and said first and second scanning units are disposed such that a plurality of light beams obtained by said first and second scanning units scanning the measurement light are approximately parallel to each other, and
wherein said third lens and said third and fourth scanning units are disposed such that a plurality of light beams obtained by said third and fourth scanning units scanning light for observation of the fundus are approximately parallel to each other.

4. The apparatus according to claim 1 , further comprising:
a dividing unit configured to divide light generated from a light source into the measurement light and the reference light;
a focus lens configured to be disposed between said dividing unit and said first and second scanning units on the optical path of the measurement light; and
a driving unit configured to drive said focus lens along the optical path of the measurement light.

5. The apparatus according to claim 4 , further comprising:
a control unit configured to control said driving unit such that the light source is disposed at a position conjugate to the fundus.

6. The apparatus according to claim 4 , further comprising:
a fiber configured to be disposed on the optical path of the measurement light,
wherein an end of said fiber is disposed at a position conjugate to the light source,
wherein said dividing unit is an optical coupler connected to the fiber, and
wherein said focus lens is disposed between the end of the fiber and said first and second scanning units.

7. The apparatus according to claim 6 , further comprising:
a second fiber configured to be disposed on the optical path of the fundus observation optical system;
a second focus lens configured to be disposed between an end of said second fiber and said third and fourth scanning units on the optical path of the fundus observation optical system; and
a second driving unit configured to drive said second focus lens along the optical path of the fundus observation optical system.

8. The apparatus according to claim 7 , further comprising:
a control unit configured to control said second driving unit such that a light source for observation of the fundus is disposed at a position conjugate to the fundus.

9. The apparatus according to claim 1 , wherein said first, second, and third lenses and said first, second, third, and fourth scanning units are disposed such that an optical magnification at a central position of said first and second scanning units conjugate to the anterior ocular segment is equal to an optical magnification at a central position of said third and fourth scanning units with respect to the anterior ocular segment.

10. The apparatus according to claim 1 , further comprising:
a dividing unit configured to divide light generated from a light source into the measurement light and the reference light,
wherein the light source generates light in which the central wavelength is 855 nm and the wavelength band width is about 100 nm, and
wherein the light for observation of the fundus is light having a wavelength of 780 nm.

11. An optical coherence tomographic apparatus which obtains a tomographic image of a fundus of an eye to be examined based on light obtained by combining return light from the fundus irradiated with measurement light through a first lens and reference light corresponding to the measurement light, the apparatus comprising:
a first scanning unit configured to be provided on an optical path of the measurement light and configured to scan the measurement light on the fundus;
a second lens configured to be disposed between said first scanning unit and the first lens on the optical path of the measurement light;
a first dichroic mirror configured to be disposed between the first lens and said second lens and configured to make the optical path of the measurement light branch off to an optical path of a fundus observation optical system for observation of the fundus, by separating light having a wavelength different from a wavelength of the measurement light;
a second scanning unit configured to be disposed on the optical path of the fundus observation optical system and configured to scan light for observation of the fundus on the fundus; and
a third lens configured to be disposed on the optical path of the fundus observation optical system and configured to be disposed between said second scanning unit and said first dichroic mirror,
wherein the optical path of the fundus observation optical system is d

Assignees

• Canon Kk

Inventors

• Yoshida Hirofumi

Classifications

• A61B3/102 Primary

  for optical coherence tomography [OCT] · CPC title

• A61B3/10 Primary

  Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions · CPC title

• A61B5/0066

  Optical coherence imaging · CPC title

• G01B2290/65

  Spatial scanning object beam · CPC title

• G01B9/02

  Interferometers · CPC title