Rapid depth scanning optical imaging device

• US 6,687,010 B1
• Filed: 09/07/2000
• Issued: 02/03/2004
• Est. Priority Date: 09/09/1999
• Status: Expired due to Term

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Hirata, Tadashi, Kaneko, Mamoru, Horii, Akihiro, Mizuno, Hitoshi
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): Kim, Richard H.
• Application Number:
  US09/656,799
• Time in Patent Office: 1,244 Days
• Field of Search: 356/479, 356/497
• US Class Current: 356/479
• CPC Class Codes: G01B 2290/20 Dispersive element for generating dispersion
• CPC Class Codes: G01B 2290/35 Mechanical variable delay line
• CPC Class Codes: G01B 2290/40 Non-mechanical variable delay line
• CPC Class Codes: G01B 2290/65 Spatial scanning object beam
• CPC Class Codes: G01B 2290/70 Using polarization in the interferometer
• CPC Class Codes: G01B 9/02003 using beat frequencies
• CPC Class Codes: G01B 9/02007 Two or more frequencies or sources used for interferometric measurement using only beat G01B9/02003
• CPC Class Codes: G01B 9/0201 using temporal phase variation
• CPC Class Codes: G01B 9/0205 of probe head
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence

Abstract

An optical imaging device includes a reference scanning unit offering a high signal-to-noise ratio and capable of scanning an object rapidly. An interference optical system can be realized inexpensively. In the optical imaging device, low coherent light passed through an optical coupler and another optical coupler, irradiated from an optical scanner probe, reflected from an observed point in a living tissue, returned to the optical coupler, propagated over a fourth SM optical fiber, and routed to another optical coupler shall be referred to as sample light. Light passed through an optical length variation optical system via the optical coupler and routed to the optical coupler shall be referred to as reference light. At this time, a difference between a delay time undergone by the sample light and a delay time undergone by the reference light is proportional to a difference between an optical length for the sample light and an optical length for the reference light. When the optical length difference falls within a coherence length, the sample light and reference light interfere with each other. An interfering signal is acquired into a computer through detectors, a differential amplifier, a demodulator, and an A/D converter.

Claims

1. An optical probe apparatus producing a signal whose components interfere with each other, comprising:

a soft elongated insertion unit capable of being inserted into a subject;

a low coherent light source;

a light introduction block including a single-mode optical fiber over which low coherent light is irradiated from the distal end of said insertion unit to an object in said subject and over which light reflected from said object is detected;

a covergence block, incorporated in the distal part of said insertion unit, for covering light emitted from said optical fiber at said object and detecting light reflected from said object;

a scanning/irradiating unit for irradiating said low coherent light emitted from said single-mode optical fiber for the purpose of scanning; and

an interference block for causing reflected light detected over said single-mode optical fiber and reference light supplied from said light source to interfere with each other,

wherein said insertion unit has a sheath that is a thin tubular member;

said scanning/irradiating unit has said light covergence block, which is fused to the distal end of said single-mode optical fiber, and a reflecting surface formed as part of said convergence block enclosed in said sheath; and

wherein at least said single-mode optical fiber and said convergence block are rotatable together within said sheath for the purpose of scanning.

2. An optical probe apparatus according to claim 1, wherein said convergence block is realized with a spherical lens.

3. An optical probe apparatus according to claim 1, wherein said convergence block is realized with a gradient index device.

4. An optical probe apparatus according to claim 1, wherein said reflecting surface is a curved surface.

5. An optical probe apparatus according to claim 1, wherein said single-mode optical fiber is covered with a fiber jacket, and said fiber jacket is processed in order to reduce abrasion.

6. An optical probe apparatus according to claim 1, wherein said single-mode optical fiber is covered with a fiber jacket, and said fiber jacket is processed in order to improve the rigidity thereof.

7. An optical probe apparatus producing a signal whose components interfere with each other, comprising:

a soft elongated insertion unit capable of being inserted into a subject;

a low coherent light source;

a light introduction block including a single-mode optical fiber over which low coherent light is irradiated from the distal end of said insertion unit to an object in said subject and over which light reflected from said object is detected;

a convergence block, incorporated in the distal part of said insertion unit, for converging light emitted from said optical fiber at said object and detecting light reflected from said object;

a scanning/irradiating unit for irradiating said low coherent light emitted from said singlemode optical fiber for the purpose of scanning; and

an interference block for causing reflected light detected over said single-mode optical fiber and reference light supplied from said light source to interfere with each other,

wherein said insertion unit has a sheath that is a thin tubular member;

said scanning/irradiating unit has said light convergence block, which is fused to the distal end of said single-mode optical fiber, and a reflecting surface formed as part of said convergence block enclosed in said sheath; and

wherein a core of said single-mode optical fiber has expanded section at an end thereof.