Measuring interferometric endoscope having a laser radiation source

• US 5,434,669 A
• Filed: 12/02/1993
• Issued: 07/18/1995
• Est. Priority Date: 10/23/1990
• Status: Expired due to Term

• Current Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Kurita, Hiroyuki, Tabata, Seiichiro, Takahashi, Susumu, Takayama, Toshikazu, Sakiyama, Katsunori
• Primary Examiner(s): Turner, Samuel A.
• Application Number:
  US08/160,258
• Time in Patent Office: 593 Days
• Field of Search: 356/345, 356/351, 356/359, 356/360, 356/241, 128/4, 128/6
• US Class Current: 356/477
• CPC Class Codes: A61B 1/042 characterised by a proximal camera, e.g. a CCD camera
• CPC Class Codes: G01B 11/2441 using interferometry

Abstract

The measuring endoscope includes a device for producing interference fringes, a device for projecting the interference fringes onto a surface of an object to be measured, a device for scanning the interference fringes, an imaging device for reading vibrations of brightness on the surface of the object to be measured which are caused by the scanning of the interference fringes and a processing device capable of determining depths of concavities and heights of convexities on the surface the measured object by calculating data output from the imaging device. This measuring endoscope makes it possible to determine accurately the location of internal diseases within organs of human bodies, defects in gas pipes and so on.

Claims

1. A measuring endoscope including an endoscope, said endoscope comprising:

an illumination optical path having;

an illumination light source provided as a light source for illuminating an object,

illumination light transmitting means composed of a plurality of optical fibers whose longitudinal directions coincide with one another, for transmitting light from said illumination light source, and

a plane of emergence for irradiating said object with the light from said illumination light transmitting means;

an observation optical path having;

an objective lens for forming an image of said object with the light reflected from said object,

image transmitting means provided substantially parallel to said illumination light transmitting means, for transmitting said object image, and

observing means for observing said object image transmitted by said image transmitting means;

a tip distal end including;

the plane of emergence of said illumination optical path, and

the objective lens of said observation optical path;

an insertable part whose one end is connected with said tip distal end, extending lengthwise in a longitudinal direction along said illumination light transmitting means and said image transmitting means to be inserted in a narrow space, said insertable part including;

said illumination light transmitting means of said illumination optical path, and

said image transmitting means of said observation optical path; and

a control part connected with the other end of said insertable part, for controlling said tip distal end and said insertable part,

wherein said measuring endoscope comprises;

a laser radiation source;

phase difference changing means connected one of inside said control part and with said control part so that an optical path length of one polarized component in at least one direction, of light emitted from said laser radiation source, is changed with respect to the optical path length of the other polarized component in the other direction perpendicular to the direction of said one polarized component, and thereby a phase difference between two polarized components perpendicular to each other is changed with respect to time;

a single optical fiber provided substantially parallel to said illumination light transmitting means and said image transmitting means in said insertable part of said endoscope, for transmitting beams of light with the phase difference caused by said phase difference changing means to said tip distal end of said endoscope;

interference fringe producing means provided in said tip distal end of said endoscope, for producing interference fringes on a surface of said object from the light with the phase difference between said two polarized components perpendicular to each other which are transmitted by said single optical fiber; and

processing means for calculating a profile of the surface of said object from an image of the interference fringes produced on the surface of said object which are transmitted, together with said object image, by said image transmitting means of said observation optical path;

wherein the phase difference is changed with respect to time by said phase difference changing means and thereby the interference fringes are scanned.

6. A measuring endoscope according to claim 1, wherein said interference fringe producing means has a polarizer for splitting light into polarized components in difference directions of vibrations and an analyzer for causing the directions of vibrations of the polarized components to coincide with each other.

2. A measuring endoscope including an endoscope, said endoscope comprising:

an illumination optical path having;

an illumination light source provided as a light source for illuminating an object,

illumination light transmitting means composed of a plurality of optical fibers whose longitudinal directions coincide with one an other, for transmitting light from said illumination light source, and

a plane of emergence for irradiating said object with the light from said illumination light transmitting means;

an observation optical path having;

an objective lens for forming an image of said object with the light reflected from said object,

image transmitting means provided substantially parallel to said illumination light transmitting means, for transmitting said object image, and

observing means for observing said object image transmitted by said image transmitting means;

a tip distal end including;

the plane of emergence of said illumination optical path, and

the objective lens of said observation optical path;

an insertable part whose one end is connected with said tip distal end, extending lengthwise in a longitudinal direction along said illumination light transmitting means and said image transmitting means to be inserted in a narrow space, said insertable part including;

said illumination light transmitting means of said illumination optical path, and

said image transmitting means of said observation optical path; and

a control part connected with the other end of said insertable part, for controlling said tip distal end and said insertable part,

wherein said measuring endoscope comprises;

a laser radiation source;

polarization state changing means connected one of inside said control part and with said control part, for changing a polarization state of beam of light emitted from said laser radiation source;

a single optical fiber provided substantially parallel to said illumination light transmitting means and said image transmitting means in said insertable part of said endoscope, for transmitting the light beam changed with respect to time of the polarization state by said polarization state changing means to said tip distal end of said endoscope;

interference fringe producing means provided in said tip distal end of said endoscope, for producing interference fringes on a surface of said endoscope, for producing interference fringes on a surface of said object from the light changed with respect to time of the polarization state which is transmitted by said single optical fiber; and

processing means for calculating a profile of the surface of said object from an image of the interference fringes produced on the surface of said object and which are transmitted, together with said object image, by said image transmitting means of said observation optical path,

wherein the polarization state is changed with respect to time by said polarization state changing means and thereby the interference fringes are scanned.

4. A measuring endoscope according to claim 2, wherein said interference fringe producing means includes at least a beam splitter for splitting a beam of light into two components, said beam splitter providing coherent light with an optical path difference and having two mirrors making an arbitrary angle for producing the interference fringes.

7. A measuring endoscope according to claim 2, wherein said interference fringe producing means has a polarizer for splitting light into polarized components in difference directions of vibrations and an analyzer for causing the directions of vibrations of the polarized components to coincide with each other.

3. A measuring endoscope including an endoscope, said endoscope comprising:

an illumination optical path having;

an illumination light source provided as a light source for illuminating an object,

illumination light transmitting means composed of a plurality of optical fibers whose longitudinal directions coincide with one another, for transmitting light from said illumination light source, and

a plane of emergence for irradiating said object with the light from said illumination light transmitting means;

an observation optical path having;

an objective lens for forming an image of said object with the light reflected from said object,

image transmitting means provided substantially parallel to said illumination light transmitting means, for transmitting said object image, and

observing means for observing said object image transmitted by said image transmitting means;

a tip distal end including;

the plane of emergence of said illumination optical path, and

the objective lens of said observation optical path;

an insertable part whose one end is connected with said tip distal end, extending lengthwise in a longitudinal direction along said illumination light transmitting means and said image transmitting means to be inserted in a narrow space, said insertable part including;

said illumination light transmitting means of said illumination optical path, and

said image transmitting means of said observation optical path; and

a control part connected with the other end of said insertable part, for controlling said tip distal end and said insertable part,

wherein said measuring endoscope comprises;

a laser radiation source;

wavelength selective means connected inside said control part or with said control part, for changing a wavelength of a beam of light, with respect to time, emitted from said laser radiation source;

a single optical fiber provided substantially parallel to said illumination light transmitting means and said image transmitting means in said insertable part of said endoscope, for transmitting the light beam changed in wavelength by said wavelength selective means to said tip distal end of said endoscope;

interference fringe producing means provided in said tip distal end of said endoscope, for producing interference fringes on a surface of said object from the light whose wavelength is changed with respect to time which is transmitted by said single optical fiber; and

processing means for calculating a profile of the surface of said object from an image of the interference fringes produced on the surface of said object which are transmitted, together with said object image, by said image transmitting means of said observation optical path,

wherein the wavelength is changed with respect to time by said wavelength selective means and thereby the interference fringes are scanned.

5. A measuring endoscope according to claim 3, wherein said interference fringe producing means includes at least a beam splitter for splitting a beam of light into two components, said beam splitter providing coherent light with an optical path difference and having two mirrors making an arbitrary angle for producing the interference fringes.

8. A measuring endoscope according to claim 3, wherein said interference fringe producing means has a polarizer for splitting light into polarized Components in difference directions of vibrations and an analyzer for causing the directions of vibrations of the polarized components to coincide with each other.