JP2003329577A - Method for generating multiple connection optical retardation with rotation reflection body in optical coherence tomography and device of optical coherence tomography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for generating multiple connection optical retardation with a rotation reflection body in optical coherence tomography and the device of optical coherence tomography with high scanning speed in a depth direction (a Z direction), capable of simultaneously and continuously imaging a tomography image. <P>SOLUTION: When dividing light form a low coherence light source 1 into two parts, object light to an object to be inspected 109 and reference light with a half mirror 3 for two-dividing to reflect the reference light via an optical retardation mechanism by the reflection body 71, the reflection body 71 is arranged so as to generate reflection in two directions with a rotation angle; the light to the two directions are combined with the light of the object recurred from the object 109 with the half mirror 3 by individually reflecting to recur the light in the two directions with a plurality of another fixation mirrors; interference light including a heterodyne interference beat signal is continuously detected and then a plurality of deep cross sections of the object 109 are simultaneously multiple connection imaged by combining to interfere the reference light with reflection light from the different required deep layer of the object 109 by arbitrarily setting the regression optical path length of the reference light from a plurality of fixation mirrors 91, 92 responding to the position of the fixation mirror. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coherence tomography apparatus and a method for generating multiple continuous light delays by a rotating reflector in optical coherence tomography, and an optical coherence tomography apparatus capable of forming multiple continuous images.

[0002]

2. Description of the Related Art As a conventional high-speed optical delay generation method in optical coherence tomography, a path of a reference optical path is a half mirror → a first mirror rotating at a high speed → a second mirror → a fixed mirror → a second mirror → a first mirror. A method is known in which the mirror is changed to a half mirror and the optical path is regressively delayed and reflected.

FIG. 7 is a schematic configuration diagram of a conventional optical coherence tomography apparatus.

In this figure, 101 is a low coherence light source [for example, SLD (super luminescence diode) light source], 102 is a half mirror (half mirror for splitting), 103 is a rotating body, and 104 is the first mirror 10.
An optical delay reflector composed of 4A and the second mirror 104B, 105 is a fixed mirror, 106 and 107 are mirrors, 109 is an object to be inspected, and 110 is a photodetector.

[0005]

However, in the above-described conventional high-speed delay method in optical coherence tomography, the number of mirrors arranged on the circumference of the rotating body is increased, instead of allowing a longer scanning distance in the depth direction (Z direction). However, there is a drawback in that many tomographic images per one rotation cannot be efficiently obtained.

In the conventional method, as shown in FIG. 7, the diagonal line of the mirror is aligned with the center line AB perpendicular to the tangent line of the rotating body, and the incident light is transmitted from the first mirror 104A to the second mirror 104B → This is considered only in the case of a return delay with respect to the fixed mirror 105, and the reflection delay in the case where the mirror reversely enters the second mirror → the first mirror by rotation is not used.

Further, for a moving object to be inspected such as a living body, it is necessary to make the scanning in the Z direction as fast as possible, but since the number of mechanical rotations is limited, a plurality of mirrors are arranged and the number of mirrors per second is increased. Increasing the number of acquired tomographic images cannot be dealt with by the above-mentioned conventional method.

Further, a method of constructing tomography by successively forming different parts or continuous parts in a single rotation in multiple layers has not been disclosed at all in other means than the above-mentioned conventional method.

In view of the above situation, the present invention provides a multiple continuous light delay by a rotating reflector in optical coherence tomography, which has a high scanning speed in the depth direction (Z direction) and can simultaneously and multiple multiple tomographic images. An object is to provide a generating method and an optical coherence tomography apparatus.

[0010]

In order to achieve the above object, the present invention provides [1] a method for generating light from a low-coherence light source in two in a multiplex continuous light delay generation method using a rotating reflector in optical coherence tomography. When the half mirror splits the object light into the object to be inspected and the reference light into two and reflects the reference light through the optical delay mechanism of the rotary reflector, the reflection in two directions occurs continuously depending on the rotation angle. Are arranged as described above, light in the two directions is reflected and returned by a plurality of different fixed mirrors, respectively, and combined with the object light returning from the object to be inspected by the half mirror for splitting, By arbitrarily setting the return optical path length of the reference light from the plurality of fixed mirrors depending on the position of the fixed mirror, the heterodyne causes multiple interference with reflected light from different desired deep layers of the inspection object. It is characterized in that interference light including an interference beat signal is continuously detected, and a plurality of deep-layer cross-sections of the object to be inspected are simultaneously and continuously imaged.

[2] In an optical coherence tomography apparatus, a low coherence light source, a half mirror for splitting the light from the low coherence light source into an object light and a reference light for an object to be inspected, and the reference light. An optical delay mechanism that delays by a rotating reflector in which a reflector is arranged so that reflection occurs continuously in two directions depending on the rotation angle, and reflection in multiple directions from this optical delay mechanism is reflected and returned at arbitrary optical distances. A plurality of fixed mirrors, the half-mirror for splitting the object light returning from the inspection object and the reference light returning from the optical delay mechanism, and the heterodyne interference synthesized by the half-mirror for splitting the two. And a photodetector for detecting interference light including a beat signal.

[3] In an optical coherence tomography apparatus, a low coherence light source, a half mirror for splitting the light from the low coherence light source into an object light and a reference light for an object to be inspected, and the reference light. An optical delay mechanism that delays by a rotating reflector in which a reflector is arranged so that reflection occurs continuously in two directions depending on the rotation angle, and reflection in multiple directions from this optical delay mechanism is reflected and returned at arbitrary optical distances. A plurality of fixed mirrors including a half mirror, a surface scanning mechanism for scanning the surface of the inspection object with the object light, an objective lens, an object light returning from the inspection object, and returning from the optical delay mechanism. The above 2 for combining with the reference light
It is characterized by comprising a splitting half mirror and a photodetector for detecting interference light containing a heterodyne interference beat signal synthesized by the splitting half mirror.

[4] In the optical coherence tomography apparatus according to the above [2] or [3], the optical delay mechanism has reflectors arranged radially on a rotating body rotating at a high speed,
In addition, the reflector enters the first mirror and reflects on the second mirror in a predetermined rotation angle range so as to recursively reflect light incident at an appropriate incident angle with respect to the normal line of the circumference of the rotor. Then, the light is reflected back by the first fixed mirror set to a predetermined optical path length, and in the next rotation angle range, the light is incident on the second mirror, reflected by the first mirror, and set separately to the predetermined optical path length. A plurality of pairs of each of the first mirror and the second mirror are arranged on the surface of the rotating body so that the second fixed mirror recursively reflects, and a plurality of fixed mirrors including half mirrors are arranged at predetermined positions. It is characterized by doing.

[5] In the optical coherence tomography apparatus according to the above [4], the reference light that has passed through the two-split mirror is split into two separate half mirrors, and the split light is used as the reference light. The optical delay mechanism arranges reflectors radially on a rotating body that rotates at a high speed, and the reflector independently supplies each of the reference lights incident at an appropriate incident angle with respect to the normal line of the circumference of the rotating body. As in the case of recursive reflection, it enters the first mirror in a predetermined angle range, is reflected by the second mirror, and is retroreflected by the first fixed mirror set to a predetermined optical path length, and reverse in the next rotation angle range. Each pair of the first mirror and the second mirror so that the light enters the second mirror, is reflected by the first mirror, and is regressively reflected by the second fixed mirror separately set to a predetermined optical path length. Place multiple pairs on the surface of the rotating body and fix multiple Characterized by placing the error in position.

[6] In the optical coherence tomography apparatus according to any one of [2] to [5] above, each of the plurality of fixed mirrors including the half mirrors is a scan start position adjusting mirror, and in the object light. It is characterized in that the optical path lengths can be independently set and adjusted so as to coincide with the Z direction which is the depth direction of the optical axis and start scanning from desired points in different depth directions.

[7] In the optical coherence tomography apparatus according to the above [4], in the optical delay mechanism, a pair of reflectors including a first mirror and a second mirror serves as an incident optical axis of the reference light. It has at least one pair of reflectors which are arranged at one point on the circumference where normal lines intersect at right angles and which enable scanning in the deep Z direction, and have a role of specifying the scanning position of the other plurality of reflectors. Is characterized by.

[8] In the optical coherence tomography apparatus according to any one of [2] to [7], a lens system in which fiber coupling is performed via a half mirror for splitting the reference light and the object light into two. And an optical fiber for object light and an optical fiber for reference light for transmitting the light from this lens system, and a lens system for making the respective outgoing lights from these optical fibers approximately parallel light fluxes. .

[0018]

[9] In the optical coherence tomography apparatus according to [3], the surface scanning mechanism includes an X-axis scanning mirror and a Y-axis scanning mirror, and the object to be inspected at a predetermined position corresponding to the plurality of delayed reference lights. It is characterized in that the surface (X-Y) of the inspected object is scanned at high speed by the object light with respect to.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

FIG. 1 is a block diagram of an optical coherence tomography apparatus for multiplex continuous imaging showing an embodiment of the present invention.

In this figure, 1 is a low coherence light source [eg, SLD (super luminescence diode) light source], 2 is a lens for fiber coupling, 3 is a half mirror (half mirror for splitting), 4 is an optical fiber for reference light, 5 and 11 are lenses for parallel rays of emitted light, 6p
Is the incident light and the return reflected light to the optical delay mechanism, 71 is the optical delay mechanism reflector consisting of the first mirror 7a and the second mirror 7b, and 7a 'is the first mirror position after the rotation of a predetermined rotation angle θp. , 7b 'are also the second mirror position after rotation, 8 is a rotating body, 91 and 92 are first and second fixed mirrors, and 91b.
Reference numerals a and 92a denote scan start position adjusting mechanisms of the first and second fixed mirrors 91 and 92 in the optical axis direction, and 6A and 6B.
Respectively, the reflection reflection delayed light, 10 are optical fibers for object light, 12 is a surface scanning mirror in the X-axis direction, 13 is a surface scanning mirror in the Y-axis direction, and 14 is an objective lens. Further, 15 is a lens, 16 is a photodetector, 17 is a PC (personal computer) system, 18 is a display device, 10
9 is an inspected object.

As described above, the optical delay mechanism is composed of the reflector 71 and the rotating body 8, and the reflecting body 71 is radially on the rotating body 8 rotating at a high speed and is appropriate to the normal line of the circumference of the rotating body 8. To reflect the reference light incident at an angle of
Reflector 7 which is a pair of the second mirror 7a and the second mirror 7a
Plural 1 are arranged.

Low coherence light source 1 such as SLD
The light wave from is split into a reference light and an object light by a half mirror 3 via a fiber coupling lens 2. The reference light propagates through the optical fiber 4 and the parallel light flux lens 5 and reaches the reflector 71 of the optical delay mechanism. When the reflector 71 is at the position of the angle indicated by the solid line, the reference light is emitted from the first mirror 7a and the second mirror 7a.
The light is reflected by the mirror 7b toward the first direction, reflected and returned along the same optical path from the first fixed mirror 91, and a predetermined optical delay length is obtained with the rotation of the reflector 71 to return to the half mirror 3. By this rotation, when the incident position of the reference light crosses the alignment boundary between the first mirror 7a and the second mirror 7b, the reference light shows the second mirror 7b 'and the first mirror 7 indicated by the dotted line.
a ', and the second fixed mirror (mirror with scan start position adjusting mechanism) 92 is reflected in the second direction. That is, the incident reference light 6p is reflected in two directions depending on the rotation angle.

With such an optical delay mechanism, the reflected light can be formed in two directions, and the first rotary reflected light 6 can be formed.
When A performs Z scanning over a predetermined optical delay extension, the second regressive reflected light 6B corresponds to the position of the second fixed mirror 92 and the object to be inspected in the same area as the first fixed mirror 91. It is also possible to perform Z scanning in the deep layer or in different domains. If the reference light continues to be reflected in the range where the rotation angle is, for example, θp, the alignment boundary points of the two mirrors are in Z scanning in different domains in the first half and the second half, that is, in the Z axis in the deep direction of the inspected object. On the other hand, it is possible to measure the reflected light distribution map that reflects the structure of the deep layer in different ranges, which is a unique feature.

Since the rotator 8 is rotating at a high speed, the reflector 71 continues to reflect the reference light in the range of the angle θp, and as a result of the shift causing the optical delay, the violet or red direction is generated depending on the rotating direction. An optical Doppler frequency shift occurs at.
The Doppler frequency shift has different shift frequencies even in the return reflection in the two directions, but the heterodyne interference beat signal is obtained according to the rotation. Utilizing the fact that the shift frequency is different between the first half and the latter half of the rotation, it is possible to identify the Z scanning position by discriminating the beat frequency and to image the distribution of reflected light from the deep layer of the inspection object.

The other object light divided into two is propagated through the object light optical fiber 10 and the parallel light beam lens 11,
Surface scanning mechanism (X-axis scanning mirror 12, Y-axis scanning mirror 1
3), enters the inspection object 109 through the objective lens 14,
The reflected light is regressively reflected on the same optical path, is combined with the reference light which is regressively reflected through the half mirror 3, and the lens 15
Is condensed by the photodetector 16 and a heterodyne interference signal is generated by the photodetector 16 to become an electric signal.

This surface scanning mechanism is synchronously driven by, for example, a galvanometer, and the object light is scanned on the XY plane by the reflection of the mirror.

Since the low coherence light source is used, the reference optical path length up to the fixed mirrors 91 and 92 and the object to be inspected 109.
An interference beat signal is generated when the optical path lengths up to are coincident with each other, and the interference beat signal is sent from the photodetector 16 to the PC (personal computer) system 17. In the PC system 17,
Frequency discrimination of the heterodyne interference signal, signal amplification, three-dimensional imaging processing, etc. are performed, and the inspection object 109 is displayed on the display device 18.
Display a tomographic image of.

The reflector 71 may be a first mirror 7a and a second mirror 7b in which surface reflection mirrors are arranged at a right angle, a right-angle prism, a three-sided reflection corner cube reflector, a retro-reflector, or a cat's eye. I do not care. However, since mechanical surface wobbling always occurs in the rotation of the rotator 8, in order to obtain a stable interference signal with the object return light, the corners of the three-sided reflection that are not affected by the surface wobbling and are stably reflected back. Cub reflectors and retro reflectors are practical.

Further, a half mirror is installed in the optical path of the object light, and the surface condition from the inspection object 109 is visualized by an image pickup device such as a CCD element to align the inspection optical axis with the inspection object. It is clear that can be done easily.

Further, conventionally, there is one fixed mirror,
The adjustment of the scanning start position was limited to only one observation area, but in the present invention, by installing a plurality of fixed mirrors and their adjustment mechanisms 91a and 92a, two or more observation areas can be simultaneously adjusted. It becomes possible to make it the target area of scanning observation.

The principle of the present invention will be described with reference to FIGS.

FIG. 2 is a geometrical explanatory view of the multiplex continuous light delay generating mechanism of the present invention, and FIG. 3 is a graph of rotation angle vs. optical delay distance of the above mechanism of the present invention.

In FIG. 2, 6p is the incident light and the return reflected light of the reference light, O is the center of rotation, PV is the normal line at the incident point P of the reference light on the circumference, OH is a line segment parallel to the incident light, and d is Is the radius of gyration of the apex of the reflecting mirror of the reflector 71, and r is the locus of rotation thereof.

First, it is assumed that the reflected light 6A starts to be generated when the apex of the reflector 71 is at the position of the rotation start angle θ1. When the rotating body 8 rotates, delayed reflected light is gradually generated, and when the incident light 6p exceeds the position of the apex and is reflected by the second mirror 7b ', the reflected light generates delayed reflected light 6B shown by a dotted line in the figure. , The delayed reflected light is gradually generated with the rotation and ends at the rotation end angle θ2. During this period, the delay distance is calculated as Z (θ) = 2d (cos θ1-cos θ2) (1). Factor 2 is due to retroreflecting with a fixed mirror and experiencing a two degree delay. For example, the delay distance when d = 30 mm is shown in FIG. In FIG. 3, the central angle θ _O indicates when the apex comes to point P in FIG. For example, the rotation angle θ1 (= 37.5 degrees) -θ _O (= 45 degrees) is about 5 mm,
Next angle theta _O (= 45 degrees) -.theta.2 (= 51.5 °) for a further delay of approximately 5mm is can be seen that to obtain.

By placing the return reflection mirrors 91 and 92 shown in FIG. 1 ahead of the reflected lights 6A and 6B so as to match the scanning start position of the domain to be observed in the deep layer of the object to be inspected 109, Multiple deep faults of about 5 mm can be independently observed in multiple rows. If the same observation area is observed by X-axis scanning instead of observing different observation areas in the deep direction Z-axis of the inspection object 109, a tomographic image can be acquired by scanning at twice the conventional observation speed. .

For example, the radius of gyration of the apex angle is d = 30 m
In the above example with m, if a size of the corner cube retro-reflector prism is 10 mm in diameter of the entrance surface and 8.6 mm in height to the apex is used, it is 18 Individuals can be placed. If the rotation speed of the rotating body is about 3300 rpm, Z scanning is 2000 lines per second,
That is, a scanning speed of 2 KHz can be realized. For example, if the number of pixels of the tomographic image is (X axis 100) × (Z axis 100), 20 tomographic images can be acquired per second, and the three-dimensional tomographic image can be easily observed at high speed in real time. . In the conventional method, the number of prisms is 4 at the above radius.
The scanning speed is limited to about 120 pieces and the scanning speed is limited to about 220 pieces per second, but in the present embodiment, 9 times speed is realized.

In the present embodiment, the optical delay distance of about 5 mm occurs almost linearly with respect to the rotation angle, and the linearity ratio is 95% or more. Furthermore, the effective rate of reflected light per rotation is about 70%, which is highly efficient.

From a simple calculation, the Doppler shift frequency generated in such an optical delay operation is f _D (θ) = 2 (d / λ ₀ ) (1-cos θ) (360 / θ) fv (2) Given. Here, λ ₀ is the center wavelength of the low coherence light source, and fv is the rotation frequency of the rotating body. In the above embodiment, since f _D (θ) = 16.4 to 21.8 MHz, the center frequency is 19 MHz and the bandwidth is about 5 MHz.
The beat signal amplifier may be used.

According to the principle of the present invention, the reflector 71 is arranged by focusing attention on the delayed light generation of only the tangential line component of the circumference parallel to the incident direction, whereas the light for the normal to the circumference is more generally arranged. The incident angle of is set to an arbitrary value and the reflector 7
Because the projection component of the arc (range of θp) drawn by 1 on the reference optical axis causes optical delay, a desired optical delay distance can be used at a higher speed, and the reflected light per rotation can be used with high efficiency. In this way, a plurality of delayed lights can be generated as shown in the next embodiment.

FIG. 4 is a view showing an embodiment of a multiplex continuous imaging optical coherence tomography apparatus incorporating the triplex continuous light delay mechanism of the present invention. In this figure, reference numeral 95 is a half mirror for retroreflection, 95a is its position adjusting mechanism, and the other constituent elements are the same as those in FIG.

The recursive reflection half mirror 95 is arranged at an appropriate position between the reflector 71 and the fixed mirror 91, so that the recursive reflection light by the reflection mirror 91 is preceded, that is, a new optical path length is obtained. The delayed light 6E can be generated, and in addition to the generation of the reference delayed light by the fixed mirrors 91 and 92, the tripled delayed light can be generated to realize triple-coupling optical coherence tomography.

FIG. 5 is a diagram showing an embodiment of a multiplex continuous imaging optical coherence tomography apparatus incorporating the quadruple continuous light delay mechanism of the present invention.

In this figure, 72 is a reflector for generating delayed light in an angle range different from that of the reflector 71, 93 and 94 are recursive reflection mirrors with an adjusting mechanism, 19 is a reference light splitting half mirror, and 20 is a mirror. Reference numerals 6C and 6D denote regressive reflected light, and the other constituent elements are the same as those in FIG.

In this embodiment, the reference light is split into two by the split half mirror 19, and one of them produces delayed light in the same angle range θp as shown in FIG. 3, for example. The other reference light can generate delayed light in different angular ranges θs or the same angular range θp. That is, the four domains in the Z direction can be independently and simultaneously Z-scanned. Furthermore, when the positions of the retroreflective mirrors 93 and 94 are adjusted so that the retroreflective light 6A, 6B, 6C, and 6D are all scanned in the same Z direction domain, the Z at about 18 times the conventional speed is used.
Scanning can be realized. In the numerical value of the above embodiment, it is 4K.
It is intended to realize a multi-sequential imaging optical coherence tomography capable of Z scanning at Hz. If the reference light is further branched, it is possible to realize visualization at 54 × speed and 12 KHz.

FIG. 6 is a diagram showing an embodiment of a multiplex continuous imaging optical coherence tomography apparatus incorporating a rotary reflector for large depth.

In this figure, 7X is a reflector for large depth,
The angle POQ is the rotation angle D of the deep depth reflector, 21 is the recursive reflection mirror, 21a is the recursive reflector position adjusting mechanism, 71 ', 7
Reference numerals 2 ', 73' ... Are rows of small depth reflectors, and the other constituent elements are the same as those in FIG.

A method of generating delayed light parallel to the incident direction of the reference light and utilizing the tangential component of the circumference is disclosed as a prior art, but it is necessary to prevent the optical axis from contacting other reflectors. Need a wide angle. In the present embodiment, such a large depth reflector 7X is arranged at a point H on the circumference where a normal line perpendicular to the incident optical axis of the reference light stands, and the light delayable angle is set to the wide angle D. On the other hand, a plurality of reflectors 71 as described in the embodiment of FIG. 3 are arranged on the other circumferential portion of the rotating body 8 every 20 degrees, for example, as described above. The tomographic image acquired by the large depth reflector 7X becomes a rough image because the number of pixels per rotation is inevitably limited if the number per rotation is one or two.

On the other hand, however, a large area can be observed in the optical delay reflector 7X having a large depth. With reference to this tomographic image of the large screen in advance, the reflectors 71 ', 72', 7 for small depth are
It is possible to observe a high-resolution tomographic image by specifying the region that can be observed by 3 '... and adjusting the fixed mirror to accurately position the desired region.

As described above, according to the multiple continuous imaging optical coherence tomography method and apparatus according to the present invention, the reference light from the half mirror 3 continuously produces delayed reflection in two directions in regions having different rotation angles. It is possible to realize simultaneous observation of different observation areas and octuple speed scanning of the same area. Further, the reference light is branched into a plurality of pieces, and a plurality of fixed mirrors 91, 92, ... By doing so, multiple continuous video can be made. None of these can be realized by the conventional high-speed optical delay generation method in optical coherence tomography, and scanning in the Z direction can be speeded up to several tens of times, and different regions are simultaneously specified and multiplexed. This is a device that can continuously observe tomographic images.

Further, according to the present invention, the effective efficiency of the reference light can be increased four times or more as compared with the conventional one, and the heterodyne beat signal can be acquired with a high SN ratio, and the highly accurate tomographic information can be obtained. Since it is possible to select and display at high speed a wide range of arbitrary multiple regions at high speed, for example, if applied to an ophthalmologic disease diagnostic device, conventionally, it relied on the intuition and experience of an ophthalmologist. Diagnosis and vitreous diagnosis can be performed easily at high speed, in a wide range of independent domains, and simultaneously, treatment by early treatment can be expected, and the burden on the patient can be greatly reduced.

Furthermore, when the multiple continuous high-speed delay method of the present invention is applied to tomographic observation with a gastric camera, it is possible to instantaneously observe a dynamic object to be inspected such as a living body without the influence of rocking. It has characteristics.

The multiple continuous imaging optical coherence tomography method and apparatus of the present invention provides highly accurate tomographic information at high speed, in a wide range of independent domains, and eliminates the influence of rocking of the object to be inspected. It is possible to take in and display in multiples and continuously, and it is particularly suitable for various medical diagnostic devices such as an ophthalmic disease diagnostic device.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention, and these modifications are not excluded from the scope of the present invention.

[0055]

As described in detail above, according to the present invention, the following effects can be achieved.

(A) The scanning speed in the depth direction (Z direction) is high, and at the same time, multiple tomographic images can be visualized continuously.

More specifically, (B), the reference light from the half mirror can continuously generate delayed reflections in two directions in regions having different rotation angles, which allows simultaneous observation of different observation regions and 8 times speed of the same region. Scanning or the like is realized, and reference beams are branched into a plurality of beams, and a plurality of fixed mirrors including half mirrors are arranged corresponding to the reference beams to enable multiple continuous image formation. None of these can be realized by the conventional high-speed optical delay generation method in optical coherence tomography, and scanning in the Z direction can be speeded up to several tens of times, and different regions are simultaneously specified and multiplexed. An apparatus capable of continuously observing tomographic images can be realized.

(C) Further, the effective efficiency of the reference light can be increased four times or more as compared with the conventional one, and the heterodyne beat signal can be acquired with a high SN ratio, and highly accurate tomographic information can be obtained at an extremely high speed and arbitrarily. Since it is possible to select and display a plurality of regions in a wide range, for example, if applied to an ophthalmic disease diagnostic device, conventionally, which relied on the intuition and experience of an ophthalmologist, the diagnosis of the fundus and the vitreous body. Diagnosis can be performed easily at high speed, in a wide range of independent domains, and simultaneously, treatment by early treatment can be expected, and the burden on the patient can be greatly reduced.

(D) Furthermore, if the multiple continuous high-speed delay method is applied to tomographic observation with a gastric camera, it is possible to instantaneously observe a dynamic inspected object such as a living body by eliminating the influence of rocking or the like. Will have.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a multiplex serial imaging optical coherence tomography apparatus according to an embodiment of the present invention.

FIG. 2 is a geometrical explanatory view of a multiplex continuous light delay generation mechanism of the present invention.

FIG. 3 is a graph of rotation angle vs. optical delay distance of the multiplex continuous light delay generation mechanism of FIG.

FIG. 4 is a diagram showing an embodiment of a multiplex continuous imaging optical coherence tomography apparatus incorporating the triplex continuous optical delay mechanism of the present invention.

FIG. 5 is a diagram showing an embodiment of a multiplex continuous imaging optical coherence tomography apparatus incorporating the quadruple continuous light delay mechanism of the present invention.

FIG. 6 is a diagram showing an embodiment of a multi-sequential imaging optical coherence tomography device incorporating a large depth rotary reflector.

FIG. 7 is a configuration diagram of a conventional optical coherence tomography apparatus.

[Explanation of symbols]

1 Low coherence light source (for example, SLD) 2,15 Fiber coupling lens 3 Half mirror (divided half mirror) 4 Reference light optical fiber 5,11 Emitting light parallel light flux lens 6A, 6B, 6C, 6D, 6E Regressive reflection Delayed light 6p Incident light to the optical delay mechanism and return reflected light 71 Optical delay mechanism Reflector 7a First mirror 7a 'First mirror position 7b Second mirror 7b' Second rotation 7b 'Predetermined rotation Second mirror position after rotation of angle θp 7X Reflector for large depth 8 Rotating body 10 Optical fiber for object light 12 Surface-scanning mirror 13 in X-axis direction 13 Surface-scanning mirror 14 in Y-axis direction Objective lens 16 Optical detection Device 17 PC (personal computer) system 18 Display device 19 Reference light splitting half mirror 20 Mirror 21 Retroreflective mirror 21a Regressive reflector position adjusting machine Structure 71 Optical delay mechanism Reflectors 71 ', 72', 73 '... Small depth reflector array 72 Reflector 91 for generating delayed light in different angular ranges First fixed mirror 92 Second fixed mirror 91a, 92a First and second fixed mirror scan start position adjusting mechanisms 93 and 94 in the optical axis direction Regressive reflection mirror 95 with adjustment mechanism Half mirror 95a for retroreflection Reflectance half mirror position adjustment mechanism 109 Inspected object O rotation center PV normal line at the incident point P of the reference light on the circumference OH line segment parallel to the incident light d radius of rotation r of the apex of the reflecting mirror of the reflector r rotation locus θ1 rotation start angle θ2 rotation end angle θp predetermined Rotation angle θs Different angle range

Claims (9)

[Claims] 1. A light from a low-coherence light source is split into two by a half mirror for splitting into an object light to an object to be inspected and a reference light, and the reference light is reflected through an optical delay mechanism by a rotary reflector. At this time, a reflector is arranged so that reflection in two directions occurs continuously depending on the rotation angle, and light in the two directions is reflected and returned by a plurality of different fixed mirrors to return from the inspection object. The object light is combined with the two-division half mirrors, and the return optical path length of the reference light from the plurality of fixed mirrors is arbitrarily set by the position of the fixed mirrors so that the desired deep layers different from the object to be inspected can be obtained. The optical coherence is characterized in that the interference light including the heterodyne interference beat signal is continuously detected by performing the multiplexed interference with the reflected light of the above, and a plurality of deep-layer cross sections of the object to be inspected are simultaneously multiplexed and imaged. For tomography A method of generating multiple continuous light delays by a rotating reflector. 2. A low-coherence light source, (b) a half-split mirror for splitting the light from the low-coherence light source into an object light and a reference light for an object to be inspected, and (c) the reference. An optical delay mechanism in which light is delayed by a rotating reflector in which a reflector is arranged so that reflection is continuously generated in two directions depending on a rotation angle, and (d) reflection in multiple directions from the optical delay mechanism is arbitrary. A plurality of fixed mirrors that return and return at optical distances; (e) the two-division half mirror that combines the object light returning from the inspection object and the reference light returning from the optical delay mechanism; An optical coherence tomography apparatus, comprising: a photodetector for detecting interference light including a heterodyne interference beat signal synthesized by the half mirror for splitting. 3. A low-coherence light source, (b) a half-split mirror for splitting light from the low-coherence light source into object light and reference light for an object to be inspected, and (c) the reference. An optical delay mechanism in which light is delayed by a rotating reflector in which a reflector is arranged so that reflection is continuously generated in two directions depending on a rotation angle, and (d) reflection in multiple directions from the optical delay mechanism is arbitrary. A plurality of fixed mirrors including a half mirror that regresses and returns at an optical distance; (e) a surface scanning mechanism that scans the surface of the inspection object with the object light; and (f) an objective lens,
(G) the half-divided half mirror for multiplexing the object light returning from the inspection object and the reference light returning from the optical delay mechanism; and (h) heterodyne interference synthesized by the half-divided half mirror. An optical coherence tomography apparatus, comprising: a photodetector that detects interference light including a beat signal. 4. The optical coherence tomography apparatus according to claim 2 or 3, wherein the optical delay mechanism radially arranges reflectors on a rotating body that rotates at a high speed, and the reflecting bodies surround the circumference of the rotating body. In order to recursively reflect the light incident at an appropriate incident angle with respect to the normal line of the first line, the first mirror is made incident on the first mirror in the predetermined rotation angle range and is reflected by the second mirror to set the predetermined optical path length. In the following rotation angle range, the light is reflected back by the fixed mirror of ## EQU1 ## and is reflected by the first mirror and then reflected by the second fixed mirror separately set to the predetermined optical path length. An optical coherence tomography apparatus, wherein a plurality of pairs of the first mirror and the second mirror are arranged on the surface of the rotating body, and a plurality of fixed mirrors including half mirrors are arranged at predetermined positions. 5. The optical coherence tomography apparatus according to claim 4, wherein the reference light that has passed through the split mirror is split into two separate half mirrors, and the split light is used as the reference light. The mechanism arranges radial reflectors on a rotating body that rotates at a high speed, and the reflecting body uniquely regresses each of the reference lights that are incident at an appropriate incident angle with respect to the normal line of the circumference of the rotating body. As described above, the light enters the first mirror in a predetermined angle range, is reflected by the second mirror, and is regressively reflected by the first fixed mirror set to a predetermined optical path length. Each pair of the first mirror and the second mirror is arranged so that the first mirror and the second mirror are incident on the second mirror, reflected by the first mirror, and regressed by the second fixed mirror separately set to have a predetermined optical path length. Place multiple pairs on the surface of the An optical coherence tomography device characterized by being placed at a position. 6. The optical coherence tomography apparatus according to claim 2, wherein each of the plurality of fixed mirrors including the half mirrors is a scan start position adjustment mirror, and the depth of the optical axis in the object light. An optical coherence tomography apparatus characterized in that the optical path lengths can be independently set and adjusted so as to start scanning from desired points in different depth directions in conformity with the Z direction which is the direction. 7. The optical coherence tomography apparatus according to claim 4, wherein in the optical delay mechanism, a pair of reflectors including a first mirror and a second mirror are orthogonal to an incident optical axis of the reference light. Place it at one point on the circumference where the normal line stands,
An optical coherence tomography apparatus, comprising at least one pair of reflectors capable of scanning in a large depth Z direction, and having a role of specifying scanning positions of the other plurality of reflectors. 8. The optical coherence tomography apparatus according to claim 2, wherein the lens system is fiber-coupled via a splitting half mirror that splits the reference light and the object light into two, and the lens. An optical coherence tomography apparatus comprising an optical fiber for object light and an optical fiber for reference light for transmitting light from the system, and a lens system for making the respective outgoing lights from these optical fibers approximately parallel light fluxes. . 9. The optical coherence tomography apparatus according to claim 3, wherein the surface scanning mechanism includes an X-axis scanning mirror and a Y-axis scanning mirror, and the object to be inspected at a predetermined position corresponding to the plurality of delayed reference lights. An optical coherence tomography apparatus, characterized in that a surface (X-Y) of an object to be inspected is scanned at high speed with object light for an object.