US 6,788,861 B1Granted

Endoscope system, scanning optical system and polygon mirror

AssigneePENTAX Corporation

InventorsTetsuya Utsui, Tetsuya Nakamura, Ryo Ozawa, Shinsuke Okada, Masaru Eguchi, Koichi Furusawa

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Abstract

An endoscope system which can obtain a tomographic image in accordance with optical coherence tomography (OCT). An OCT section of the endoscope system comprises a first optical fiber, a second optical fiber, an optical coupler, a super-luminescent diode (SLD), a photodetector, and a reference mirror. The first optical fiber is opposed to the SLD at its proximal end. The second optical fiber is opposed to the photodetector at its proximal end. The optical coupler establishes optical connection between the optical fibers. The reference mirror is arranged movable in front of the distal end of the second optical fiber. The distal end of the first optical fiber is introduced to an OCT scanning unit at a tip of an endoscope. This OCT scanning unit includes a polygon mirror having a plurality of reflecting surfaces, which are tilted in different angles from each other. The OCT scanning unit forms a plurality of scanning lines aligned in parallel over a subject at regular intervals. Here, the OCT scanning unit irradiates the subject with light emitted from the distal end of the first optical fiber, and introduces the light reflected by the object to the first optical fiber.

An endoscope system comprising:

a first waveguide;
a second waveguide;
an optical coupler configured to optically couple said first waveguide to said second waveguide;
a low-coherent light source provided on a proximal end of one of said first and second waveguides, said low-coherent light source emitting low-coherent light to be incident on the waveguide provided with said low-coherent light source;
a polygon mirror having a plurality of reflecting surfaces around its center axis, said reflecting surfaces differing from one another in tilt angle with respect to said center axis;
a supporting mechanism which supports said polygon mirror and rotates it about said center axis, said supporting mechanism being provided in an insertion portion of said endoscope system;
an incident optical member which guides low-coherent light emitted from a distal end of said first waveguide to a reflecting surface of said polygon mirror, said incident optical member being provided in said insertion portion;
an emission optical member which converges the low-coherent light reflected by said polygon mirror, said emission optical member being provided in said insertion portion;
a reflecting member which reflects the low-coherent light emitted from a distal end of said second waveguide so that the low-coherent light returns to said second waveguide as reference light;
an optical path length adjusting mechanism configured to enable a relative change between a length of an optical path extending from said optical coupler to an object through said first waveguide and a length of another optical path extending from said optical coupler to said reflecting member through said second waveguide;
a photodetector provided on a proximal end of the other of said first waveguide and said second waveguide, said photodetector receiving light from said other of said first waveguide and said second waveguide;
and
a signal processor configured to generate a tomographic image of the object on the basis of a detection signal output from said photodetector while said optical path length adjusting mechanism makes the relative change and while said support mechanism rotates said polygon mirror.

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Abstract

Claims10