WO2012140926A1 - Optical coherence tomography apparatus and optical coherence tomography method - Google Patents

Abstract

The optical coherence tomography apparatus (1) comprises: a light source (11) that irradiates laser light; an optical splitter (12) that divides the laser light into measuring light that is irradiated on a subject (S) and reference light that is irradiated on a reference mirror (21); a probe (30) that receives scattered light returning after being scattered inside the subject (S); and an optical multiplexer (16) that combines reflected light returning after being reflected by the reference mirror (21) with the scattered light to generate interference light. The apparatus analyzes the interference light and generates an optical coherence tomographic image. The laser light is highly coherent light with a coherence length of 10 mm or more. The probe (30) is equipped with a focus lens (34) that focuses the measuring light on the subject (S), and a focal point adjustment mechanism (35) for adjusting the focal point by adjusting the distance between the focus lens (34) and the subject (S).

Description

Optical coherence tomographic image generating apparatus and optical coherent tomographic image generating method

The present invention relates to an optical coherent tomographic image generation apparatus and an optical coherent tomographic image generation method for capturing a tomographic image inside an object using coherent light, and more particularly to an optical coherent tomographic image using high coherent light. The present invention relates to an image generation apparatus and an optical coherence tomographic image generation method.

Conventionally, an optical coherence tomographic image generation apparatus (Optical Coherence Tomography: hereinafter referred to as an OCT apparatus) is applied in ophthalmic medicine such as tomographic measurement of an eyeball cornea or a retina in the field of living bodies. OCT methods are broadly divided into TD (Time Domain) -OCT and FD (Frequency Domain) -OCT. The latter FD-OCT is classified into SD (Spectrum Domain) -OCT and SS (Swept Source) -OCT. It is known to be classified.

For example, SS-OCT is a method in which a laser light source capable of continuously sweeping wavelengths (wave numbers) is used, spectral information acquired by a detector is processed by FFT (Fast Fourier Transform), and an optical path length is specified. SS-OCT has features such as higher resolution and real-time measurement than X-ray imaging devices and CT (Computed Tomography) devices.
In addition, TD-OCT has been tried for dental use, but since SS-OCT can acquire data with higher sensitivity and higher speed than TD-OCT, motion artifact (ghost due to body movement) It is characterized by being strong.

In an OCT apparatus in the field of dentistry, a handpiece (probe) for a dental photodiagnostic device is provided with OCT means, and means for positioning a photodiagnostic portion of a tooth part is an imaging method using a camera, and for acquiring a surface image inside. (Refer to Patent Document 1).

The probe of Patent Document 1 includes a collimating lens installed at the tip of an optical fiber for signal light transmission of low-coherent light generated outside, two reflecting mirrors for reflecting signal light from the collimating lens, and a reflection thereof. An oblique mirror that reflects light reflected from the mirror in a right angle direction, a condenser lens that collects the signal light from the oblique mirror, an irradiation window that irradiates the signal light toward the subject, and an oblique mirror (from the irradiation window) The motor for rotating the signal light) is installed in an elongated cylindrical handpiece. And the reflected light from the predetermined area | region of a tooth | gear part is transmitted along the above-mentioned transmission path reversely.

Utility Model Registration No. 3118718 (Claim 2, FIG. 2)

However, since the probe of Patent Document 1 employs low-coherent light and has a short coherent distance (coherent length), it can only generate a light coherence tomographic image in a narrow range with respect to the laser irradiation direction on the subject. There was a problem.

For this reason, the probe of Patent Document 1 has a problem that it is difficult to find the target affected area because it cannot search the affected area in a wide range while viewing the subject as a whole.

Therefore, the present invention has been invented to solve such a problem, and an optical coherence tomographic image generation apparatus and an optical coherence tomography capable of generating an optical coherence tomographic image over a wide range in a subject to be photographed. It is an object to provide an image generation method.

In order to solve the above problems, an optical coherence tomographic image generation apparatus according to the present invention includes a light source that periodically irradiates a laser beam having a high-band wavelength, a measurement light that irradiates the subject with the laser beam, and a reference mirror. An optical splitter that distributes the reference light to be irradiated, a probe that irradiates the subject with the measurement light and receives scattered light that is scattered and returned inside the subject, and the reference light is reflected from the reference mirror And an optical multiplexer that generates interference light by combining the reflected light that has returned and the scattered light, and generates an optical coherence tomographic image by analyzing the interference light and generating an optical coherence tomographic image The apparatus is an apparatus, wherein the laser beam is highly coherent light having a coherence distance of 10 mm or more, and the probe is a condensing lens that condenses the measurement light on the subject, and the condensing lens and the subject Adjust the distance to Characterized by comprising a converging point adjusting mechanism for adjusting the point, the.

According to such a configuration, since the laser light serving as the light source is highly coherent light, an optical coherence tomographic image (hereinafter simply referred to as “tomographic image”) over a wide range in the depth direction with respect to the laser irradiation direction on the subject. ) Can be generated.
In addition, the optical coherence tomographic image generation apparatus according to the present invention can adjust the condensing point of the laser beam with respect to the depth direction with respect to the laser irradiation direction in the subject by providing the condensing point adjusting mechanism. Therefore, a sharper tomographic image at the depth of the target portion can be generated by aligning the focal point with a desired position in the depth direction.
For this reason, the optical coherence tomographic image generation apparatus according to the present invention can search the affected area over a wide range while looking at the subject as a whole, and thus can quickly and surely find the affected area. Then, the focused point adjusting mechanism can generate a clear tomographic image of the target region by matching the focused point of the laser beam to the depth of the affected part that has been found.
Here, the coherent distance (coherent length) corresponds to a distance when the attenuation of the power spectrum is 6 dB.

Further, in the optical coherence tomographic image generation device according to the present invention, the condensing point adjustment mechanism moves the condensing lens in the optical axis direction of the measurement light to determine the distance between the condensing lens and the subject. It is preferable to provide a condenser lens moving mechanism for adjustment.

According to this configuration, the optical path length from the subject to the optical multiplexer is changed by providing the condenser lens moving mechanism that adjusts the distance between the condenser lens and the subject by moving the condenser lens in the optical axis direction. It is possible to adjust the condensing point without doing so. For this reason, since the scattered light and the reflected light can be combined under the same conditions, the analysis of the interference light can be easily performed.

Further, in the optical coherence tomographic image generation device according to the present invention, the probe has a nozzle that is attached to the tip of the probe and makes contact with the subject, and the focusing point adjustment mechanism advances or retracts the nozzle, or It is preferable to provide a nozzle expansion / contraction mechanism that adjusts the distance between the condenser lens and the subject by changing the nozzle length.

According to such a configuration, the probe can suppress the tomographic image from shaking by photographing the subject with the tip of the nozzle in contact with the subject. Furthermore, the condensing point adjusting mechanism is provided with a nozzle expansion / contraction mechanism so that the distance between the condensing lens and the subject can be adjusted by moving the nozzle back and forth or by changing the nozzle length, thereby focusing the laser beam. By adjusting this, it is possible to generate a clearer tomographic image at a position in the predetermined depth direction of the subject.

In the optical coherence tomographic image generation apparatus provided with the nozzle expansion / contraction mechanism according to the present invention, a collimator for converging the reference light divided by the optical splitter into parallel light, and the parallel light converged by the collimator A reference light condensing lens that condenses the reference mirror, and an optical path length changing unit that changes the optical path length from the optical splitter to the reference mirror by moving the collimator in the optical axis direction. It is preferable.

According to such a configuration, the optical coherence tomographic image generation apparatus includes the optical path length changing unit that changes the optical path length from the optical splitter to the reference mirror, so that the optical path from the subject to the optical multiplexer by the nozzle expansion / contraction mechanism. Even when the length is changed, the optical path lengths of the scattered light and the reflected light can be matched, so that the analysis of the interference light can be easily performed.

In the optical coherent tomographic image generation device according to the present invention, it is more preferable that the coherent distance of the highly coherent light is less than 48 mm.

According to such a configuration, an OCT apparatus equipped with a light source having a coherent distance of 48 mm or more as a coherent distance (coherent length) of highly coherent light is theoretically possible, but this light source has a stepped wave number (wavelength). Since the SS-OCT method is used to sweep the light, it is difficult to manufacture the light source itself when the overall performance including the sweep speed and resolution is required for this light source. Is.

Further, the optical coherence tomographic image generation method according to the present invention distributes the laser light emitted from the light source to the measurement light that irradiates the subject and the reference light that irradiates the reference mirror, and the scattered light reflected from the subject. An optical coherence tomographic image generation method for analyzing and diagnosing interference light obtained by combining reflected light from the reference mirror, wherein the laser light uses highly coherent light having a coherence distance of less than 48 mm, Adjusting a distance between a condensing lens for condensing measurement light on the subject and the subject, and adjusting a condensing point within a coherent range with respect to the coherent distance to obtain an optical coherence tomographic image. To do.

According to such a configuration, since the optical coherence tomographic image generation method uses highly coherent light whose coherence distance of laser light is less than 48 mm, a wider range in the depth direction with respect to the laser irradiation direction on the subject than before. A tomographic image can be generated over a wide range. Further, according to this optical coherence tomographic image generation method, the distance between the condensing lens and the subject is adjusted, and the focal point is adjusted within the coherent range with respect to the coherent distance. It is possible to generate a clearer tomographic image at the position at.

The optical coherence tomographic image generation apparatus and optical coherence tomographic image generation method according to the present invention can generate an optical coherence tomographic image over a wide range of a subject to be photographed. In addition, a clear optical coherence tomographic image at a desired position with respect to the depth direction of the subject can be generated.
For this reason, the optical coherence tomographic image generation apparatus according to the present invention can search the affected area over a wide range while looking at the subject as a whole, and thus can quickly and surely find the affected area. In addition, a clear tomographic image of the target region can be generated by matching the focal point of the laser beam to the depth of the affected part.

1A and 1B are external views of an optical coherence tomographic image generation apparatus according to an embodiment of the present invention, in which FIG. 1A shows a single joint arm type and FIG. It is a block diagram which shows typically the unit structure of the optical coherence tomographic image generation apparatus which concerns on embodiment of this invention. It is a principal part perspective view which shows the structure around the reference mirror of the optical coherence tomographic image generation device which concerns on embodiment of this invention. It is a perspective view of the diagnostic probe part of the optical coherence tomographic image generation device concerning the embodiment of the present invention. It is a central part longitudinal cross-sectional view of the diagnostic probe part of the optical coherence tomographic image generation device concerning the embodiment of the present invention. It is a principal part disassembled perspective view of the diagnostic probe part of the optical coherence tomographic image generation device concerning the embodiment of the present invention. It is a principal part disassembled perspective view which shows the attachment or detachment state of the nozzle of the optical coherence tomographic image generation apparatus which concerns on embodiment of this invention. It is a principal part expanded vertical sectional view which shows the installation state of the nozzle of the optical coherence tomographic image generation apparatus which concerns on embodiment of this invention. It is a figure which shows the 1st modification of the optical coherence tomographic image generation apparatus which concerns on embodiment of this invention, and is a principal part disassembled perspective view of a diagnostic probe part. It is a figure which shows the 2nd modification of the optical coherence tomographic image generation apparatus which concerns on embodiment of this invention, and is a perspective view of a diagnostic probe part. It is a figure which shows the 2nd modification of the optical coherence tomographic image generation apparatus which concerns on embodiment of this invention, and is a principal part disassembled perspective view of a diagnostic probe part. It is a figure which shows the 2nd modification of the optical coherence tomographic image generating apparatus which concerns on embodiment of this invention, and is a center part longitudinal cross-sectional view of a diagnostic probe part. It is a figure which shows the 2nd modification of the optical coherence tomographic image generation apparatus which concerns on embodiment of this invention, and is a principal part expanded vertical sectional view which shows the installation state of a nozzle. It is a figure which shows the 3rd modification of the optical coherence tomographic image generation apparatus which concerns on embodiment of this invention, and is a principal part disassembled perspective view of the diagnostic probe part provided with the nozzle expansion-contraction mechanism. It is a figure which shows the 3rd modification of the optical coherence tomographic image production | generation apparatus which concerns on embodiment of this invention, and is a principal part expanded longitudinal cross-sectional view of the diagnostic probe part provided with the nozzle expansion-contraction mechanism. It is a figure which shows the 3rd modification of the optical coherence tomographic image generation apparatus which concerns on embodiment of this invention, and is a principal part perspective view of an optical path length change means.

Hereinafter, an OCT apparatus 1 that is an optical coherence tomographic image generation apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Overview of OCT system configuration]
An outline of the configuration of the OCT apparatus 1 will be described by taking as an example a case where the subject (sample S) to be imaged by the OCT apparatus 1 is a tooth (anterior tooth) to be diagnosed by a dental patient. As shown in FIGS. 1 and 2, the OCT apparatus 1 mainly includes an optical unit unit 10 (optical unit), a diagnostic probe unit 30 (probe), and a control unit unit 50 (control unit).
The OCT apparatus 1 distributes the laser light emitted from the light source 11 to the measurement light that irradiates the sample S (subject) and the reference light that irradiates the reference mirror 21 by the coupler 12 (light splitter), and the diagnostic probe unit. 30. Interference obtained by combining the reflected light from the reference mirror 21 with the reflected light from the reference mirror 21 and the scattered light that is returned from the sample S after being irradiated with the measurement light on the sample S by the coupler 16 An optical coherence tomographic image generation apparatus that analyzes light and generates an optical coherent tomographic image.

≪Optical unit part≫
The optical unit (optical unit) 10 includes a light source, an optical system, and a detection unit to which each method of general optical coherence tomography can be applied. As shown in FIG. 2, the optical unit 10 includes a light source 11 that continuously (periodically) irradiates a sample (subject) S with laser light having a high band wavelength, and measurement light that irradiates the sample S with laser light. And a coupler 12 (light splitter) that distributes the reference light to be irradiated to the reference mirror 21 and a diagnostic probe unit that irradiates the sample S with the measurement light and scatters the sample S and returns the scattered light. 30 (probe), a coupler 16 (optical combiner) that generates interference light by synthesizing the reflected light and the reflected light that are reflected from the reference mirror 21 and returned from the reference mirror 21, and a sample S from the interference light. Detector 23 for detecting the internal information of the optical fiber 19d, optical fiber 19d (60) provided in the optical path between the light source 11 and the detector 23, and other optical components.

Here, an outline of the optical unit unit 10 will be described.
Light emitted from the light source 11 is divided into measurement light and reference light by a coupler 12 which is a light splitter. The measurement light enters the diagnostic probe unit 30 from the circulator 14 of the sample arm 13. This measurement light is condensed on the sample S by the condenser lens 34 via the light receiving lens 32 (collimator lens) and the scanning means 33 (galvano mirror) when the shutter 312 of the shutter mechanism 31 of the diagnostic probe unit 30 is open. Then, after being reflected and scattered, it returns to the circulator 14 of the sample arm 13 through the condenser lens 34, the scanning means 33, and the light receiving lens 32 again. The polarization component of the returned measurement light is returned to a state with less polarization by the polarization controller 15 and input to the detector 23 via the coupler 16 as an optical multiplexer.

On the other hand, the reference light separated by the coupler 12 for the light splitter is collected on the reference mirror 21 (reference mirror) by the reference light condensing lens 20 from the circulator 18 of the reference arm 17 through the collimator lens 19 and the optical path length changing means 24. After being reflected and reflected there, the light returns to the circulator 18 through the reference light condensing lens 20 and the collimator lens 19 again. The polarization component of the returned reference light is returned to a state with less polarization by the polarization controller 22 and input to the detector 23 via the coupler 16 for the optical multiplexer. That is, since the coupler 16 combines the measurement light scattered and reflected by the sample S and the reflected light reflected by the reference mirror 21, the detector 23 detects the light (interference light) interfered by the multiplexing. It can be detected as internal information of the sample S.

<Light source>
As the light source 11, for example, a laser light source for SS-OCT method can be used.
In this case, it is preferable that the light source 11 has a performance with a center wavelength of 1310 nm, a sweep wavelength width of 100 nm, a sweep speed of 50 kHz, and a coherence distance (coherent length) of 14 mm.
Here, the coherent distance corresponds to a distance when the attenuation of the power spectrum is 6 dB. In addition, although the coherence distance of a laser beam is 10 mm or more and highly coherent light of less than 48 mm is preferable, it is not limited to this.

<Reference collimator lens>
The reference light collimator lens 19 (see FIG. 2) is a lens that converges the reference light divided by the coupler 12 (light splitter) into parallel light. As shown in FIG. 3, the collimator lens 19 ′ includes a collimator lens 19 ′. 19d is accommodated in a substantially cylindrical lens holder 19a.
The collimator lens unit 19 ′ supports a collimator 19d, a collimator holder 19e that holds the collimator 19d, a block 19f that supports the collimator holder 19e, and a block 19f that can be finely adjusted in a direction perpendicular to the optical axis. A bracket 19h, a support base 191 for holding the bracket 19h, a backlash preventing member 192 for engaging the support base 191 with the support frame member 194, and a fixture 193 for fixing the support base 191 to the support frame member 194 The support frame member 194 is mainly provided.

The collimator 19d includes the collimator lens 19, a substantially cylindrical lens holder 19a in which the collimator lens 19 is fitted, a connector 19c attached to the lens holder 19a, one end connected to the connector 19c, and the other end to the lens holder. 19a and an optical fiber 19b connected to the circulator 18 (see FIG. 2).

In the lens holder 19a, an optical fiber 19b is attached to one end on the optical axis and the connector 19c is fixed, and an opening is formed on the other end toward the reference mirror 21 and through which reference light and reflected light enter and exit. Yes.
The collimator holder 19e is fixed on the block 19f by screwing the lens holder 19a forward and backward in the optical axis direction so as to be finely adjustable.
The block 19f is supported so as to be finely adjustable in a direction perpendicular to the optical axis via a compression coil spring SP in a substantially U-shaped bracket 19h when viewed from the front.
The bracket 19h is fixed to and integrated with the support base 191.

The support table 191 is a member that mounts a collimator lens unit 19 ′ fixed to the support table 191 and supports the collimator lens unit 19 ′ so that the position of the collimator lens unit 19 ′ can be adjusted with respect to the support frame member 194 in the optical axis direction. The support base 191 is a substantially U-shaped thick plate member that is slidably engaged with the support frame member 194 in the optical axis direction, and is continuously provided so as to straddle the support frame member 194. . The support base 191 is provided with a sliding surface 191a disposed in a state in which the bracket 19h is in contact with the support frame member 194 from both ends of a flat plate-like portion where the sliding surface 191a is formed. A pair of left and right engaging projections 191b and a convex portion 191c formed between the left and right engaging projections 191b and abutting against the rail-shaped portion of the support frame member 194 are formed.

The fixing tool 193 includes a fastening member for fixing the backlash preventing member 192 engaged with one engaging protrusion 191b of the support base 191 to the engaging protrusion 191b, and is fixed to a predetermined position of the support frame member 194. Is for.
With this configuration, the collimator 19d can be disposed at a position on the optical axis set in advance so that the optical path length on the sample S (subject) light side is equal to the optical path length on the reference light side.

The reference light condensing lens 20 is a lens that condenses the parallel light converged by the collimator lens 19 on the reference mirror 21. For example, the reference light condensing lens 20 is preset between the collimator lens 19 on the support frame member 194 and the reference mirror 21. Is arranged at a position on the optical axis. The reference light condensing lens 20 is supported by the support base 20a so that the inclination of the reference light condensing lens 20 can be adjusted, and the support base 20a is fastened to the support frame member 194 so as to be movable and fixed in the optical axis direction. The fixing tool 20b is fixed to a predetermined position of the support frame member 194.

The support frame member 194 is a plate-like member extending in the optical axis direction. The collimator lens unit 19 ′, the reference light condensing lens 20, and the like are disposed at predetermined intervals on the support frame member 194 at appropriate intervals. And the reference mirror 21 is mounted. For example, a reference mirror 21 is fixed to one end of the support frame member 194, and a reference light condensing lens 20 and a collimator 19d are sequentially arranged from the reference mirror 21 through an appropriate distance to move the collimator 19d. By doing so, the optical path length can be changed.

<Optical path length changing means for reference light>
As shown in FIG. 2, the optical path length changing unit 24 for the reference light moves the collimator 19d in the optical axis direction to change the optical path length from the coupler 12 (light splitter) to the reference mirror 21 or to perform initial setting. It is a device used when doing. The optical path length changing means 24 of the reference light includes, for example, a collimator lens unit 19 ′ that holds the collimator 19d and is arranged so as to be able to advance or retract manually or electrically along the optical axis together with the collimator 19d. The optical lens 20, the reference mirror 21, a collimator lens unit 19 ′, a reference light collecting lens 20, and a support frame member 194 that supports the reference mirror 21 are configured.

≪Diagnostic probe part≫
As shown in FIG. 2, the diagnostic probe unit 30 (probe) includes scanning means 33 (galvanometer mirror) for two-dimensionally scanning laser light, guides the laser light from the optical unit unit 10 to the sample S, and samples S The scattered light reflected and scattered inside is received and guided to the optical unit 10. The diagnostic probe unit 30 includes a cable 60, a housing 3, a frame body 300, a shutter mechanism 31, a light receiving lens 32, a scanning unit (galvano mirror), a condensing lens 34, and a condensing point, which will be described later. An adjustment mechanism 35 and a nozzle 37 are provided.

<Cable>
The cable 60 (see FIG. 1) is for optically and electrically connecting the diagnostic probe unit 30, the optical unit unit 10, and the control unit unit 50. The cable 60 includes an optical fiber connected to the optical unit unit 10 and a communication line connected to the control unit unit 50.

When the imaging is not in progress, the housing 3 of the diagnostic probe section 30 is, as shown in FIG. 1A, a single joint arm 70 extending in the horizontal direction from the lower side of the display device 54 arranged on the upper portion of the OCT apparatus 1. It is held by the holder 71 at the tip of the head. As a result, even when the cable 60 is stored, the cable 60 can be stored without being twisted, and the storage space can be reduced.

On the other hand, at the time of imaging, the user removes and grasps the diagnostic probe unit 30 from the holder 71 of the single joint arm 70 and brings the diagnostic probe unit 30 into contact with the patient's teeth (sample S) to prevent camera shake. . At this time, even if both hands of the user are blocked, in order to operate the operation button SW (see FIG. 4) for starting photographing, the foot controller 80 (FIG. 1) connected to the control unit 50 so as to be communicable by wire or wirelessly. Reference) can also be used.

When the OCT apparatus 1A shown in FIG. 1B is not in the middle of imaging, the diagnostic probe unit 30 includes an articulated arm 70A that extends horizontally from the upper side of the display device 54 disposed on the OCT apparatus 1A. The OCT apparatus 1 is the same as the OCT apparatus 1 shown in FIG. 1A except that it can be held by the holder 71 at the tip. The articulated arm 70A has a longer length from the proximal end to the distal end holder 71 than the single-joint arm 70, and is disposed at a higher position from the floor. Therefore, the drooping of the cable 60 can be reduced. Thereby, operability can be improved and it can prevent having stepped on the cable 60 which hung down accidentally.

<Housing>
As shown in FIGS. 4 and 5, the housing 3 is a case body that covers or supports the components of the frame body 300 and the diagnostic probe unit 30, and has a substantially cross shape (substantially pistol shape) when viewed from the side. Is formed. For this reason, it is easy to hold, has good operability, and has a shape that can be easily attached to the holder 71. The housing 3 is formed with a scanning means storage portion 3a, a grip portion 3b, a condenser lens storage portion 3c, an X-direction galvanometer mirror storage portion 3d, and a Y-direction galvanometer mirror storage portion 3e, which will be described later. Yes. In the housing 3, a frame main body 300, a light receiving lens 32, a scanning unit 33, a condenser lens 34, and a shutter mechanism 31 are mainly provided. The housing 3 is formed by, for example, matching two case bodies that are divided into right and left by longitudinally sectioning the central portion.

The scanning means storage portion 3 a is a portion for storing the scanning means 33 disposed at a substantially central portion of the substantially cross-shaped housing 3.
The grip portion 3b is a portion that is gripped when the user holds the diagnostic probe portion 30 by hand and is a portion that is held by the holder 71 (see FIG. 2). The grip portion 3b extends downward (in the direction of arrow B) from the position where the scanning means storage portion 3a is disposed, and is formed in a substantially cylindrical shape. The grip portion 3b is arranged such that the operation button SW is disposed on the outer peripheral surface on the nozzle 37 side, the light receiving lens 32 and the like are accommodated therein, and the cable 60 is drawn out on the lower surface.

The condensing lens storage unit 3 c is a part that stores the condensing lens 34 and the condensing point adjustment mechanism 35 and supports the nozzle 37 and the operation knob 351. The condensing lens storage portion 3c is formed so as to extend in a direction orthogonal to the grip portion 3b, and is formed in a substantially cylindrical shape from the scanning means storage portion 3a toward the front (arrow A direction).
The X-direction galvanometer mirror storage portion 3d is a portion in which the drive motor, the connector portion, and the like of the X-direction galvanometer mirror 33X are stored, and protrudes in a state in which the X-direction galvano mirror storage portion bulges backward from the arrangement position of the scanning means storage portion 3a. .
The Y-direction galvanometer mirror housing portion 3e is a portion in which the drive motor, connector portion, and the like of the Y-direction galvanometer mirror 33Y are housed, and protrudes in a state in which the Y-direction galvanometer mirror housing portion 3e bulges upward from the arrangement position of the scanning means housing portion 3a.

<Frame body>
As shown in FIG. 6, the frame main body 300 is a thick plate-like member that holds the shutter mechanism 31, the optical axis adjustment mechanism 321, the scanning means 33, and the condensing point adjustment mechanism 35, and is screwed into the housing 3. ing. The frame main body 300 is formed in a substantially cross shape (substantially pistol shape) in a side view according to the shape of the housing 3. The frame body 300 is formed with an L-shaped portion 300a in which the scanning means 33 is fixed at the central portion, and a vertical portion that is formed to extend downward from the central portion and to which the shutter mechanism 31 and the optical axis adjusting mechanism 321 are fixed. 300b, a horizontal portion 300c formed to extend from the central L-shaped portion 300a to the front side, to which the condensing point adjusting mechanism 35 is fixed, and a position adjusting hole 301 extending vertically in the vertical portion 300b. And the position adjustment hole 302 extended in the horizontal direction in the horizontal part 300c is formed.

The position adjustment hole 301 is a long hole formed in the vertical portion 300b so as to extend in the optical axis direction of the measurement light, and supports the light receiving lens bracket 324 so as to be movable and tiltable in the optical axis direction. A bracket fastener 327 for fastening 324 in a predetermined direction and position is inserted so as to be movable up and down.
The position adjusting hole 302 is a long hole for movably installing a condensing point adjusting mechanism 35 that advances and retracts the condensing lens 34 along the optical axis, and an adjustment screw 353 is movably inserted therein.

<Shutter mechanism>
As shown in FIG. 6, in the shutter mechanism 31, the measurement light sent from the circulator 14 (see FIG. 2) and the scattered light reflected by the measurement light hitting the sample S pass through the diagnostic probe unit 30. For example, it is interposed between the light receiving lens 32 in the grip portion 3b and the scanning means 33 in the scanning means storage portion 3a. The shutter mechanism 31 includes, for example, a shutter base 311, a shutter 312, shutter driving means 313, and a shutter base fastener 314. The shutter mechanism 31 is for performing zero point correction by blocking the reflected light from the sample S by the shutter 312 and removing noise (image) appearing on the display screen in a software manner.

The shutter base 311 is a member to which the shutter 312 and the shutter driving unit 313 are attached, and is fixed to the frame main body 300 so as to be vertically movable by the shutter base fastener 314. In the shutter base 311, a through hole 311a through which measurement light and scattered light pass is formed on the optical axis in the vertical direction. The shutter base 311 can be rotated around the shutter base fastener 314 by loosening the fastening of the shutter base fastener 314.
The shutter 312 is a member that blocks measurement light and scattered light that pass through the through-hole 311a, and is arranged so as to open and close the through-hole 311a by rotating around a drive shaft (not shown) of the shutter drive unit 313. It consists of the plate member made.

The shutter driving unit 313 is an actuator that opens and closes the through hole 311a by moving the shutter 312 on the optical axis or retracting the shutter 312 from the optical axis. The shutter driving unit 313 includes, for example, a motor that rotates the shutter 312 to open and close the through hole 311a, or a solenoid that opens and closes the shutter 312 to open and close the through hole 311a.
The shutter base fastener 314 is a screw member for fixing the shutter base 311 to the frame body 300 so as to be movable in the vertical direction. The shutter base fastener 314 is inserted into the position adjustment hole 301 of the frame main body 300 and screwed to the shutter base 311.
The shutter mechanism 31 may be a mechanism that manually moves the shutter 312.

<Light receiving lens>
As shown in FIGS. 5 and 6, the light receiving lens 32 is a lens that receives measurement light sent from the coupler 12 (see FIG. 2) via the circulator 14 and adjusts the laser diameter. It consists of a collimator lens that converges to. The light receiving lens 32 is installed in a substantially cylindrical light receiving lens unit 322 and is rotatably attached to the lower portion of the frame body 300 with a light receiving lens holder 323 and a light receiving lens bracket 324 interposed therebetween.

<Optical axis adjustment mechanism>
As shown in FIG. 6, the optical axis adjustment mechanism 321 is a device that adjusts the direction and position of the light receiving lens 32 by tilting or moving the light receiving lens unit 322 provided with the light receiving lens 32 relative to the optical axis. is there. The optical axis adjusting mechanism 321 includes a light receiving lens unit 322, a light receiving lens holder 323, a light receiving lens bracket 324, a unit fastener 325, a holder fastener 326, and a bracket fastener 327, which will be described later. Has been.

The light receiving lens unit 322 is a substantially cylindrical member in which the light receiving lens 32 is provided, and is disposed in the vertical direction along the optical axis.
The light-receiving lens holder 323 is a member that holds the light-receiving lens unit 322 so as to be rotatable about the optical axis. The light-receiving lens unit 322 has a through-hole 323a into which the light-receiving lens unit 322 is inserted, and a notch 323b that is notched in the through-hole 323a. And a screw hole (not shown) into which the unit fastener 325 and the holder fastener 326 are screwed together.

The light receiving lens bracket 324 holds the light receiving lens holder 323 so as to be rotatable about a holder fastener 326 disposed in one horizontal direction (direction A in FIG. 6, a direction perpendicular to the optical axis). . The light-receiving lens bracket 324 is rotatably held around a holder fastener 326 disposed in another horizontal direction (direction B in FIG. 6, a direction orthogonal to one direction orthogonal to the optical axis). It is fixed to the frame body 300.
The light receiving lens bracket 324 is a member that is attached to the frame body 300 in the housing 3 so that the position of the light receiving lens bracket 324 can be adjusted in the direction B in FIG. 6, and is made of a thick plate material that is substantially L-shaped in plan view. The light receiving lens bracket 324 is formed with a hole (not shown) into which the holder fastener 326 is inserted and a screw hole (not shown) into which the bracket fastener 327 is screwed.
The unit fastener 325 is a fastening for loosening the light receiving lens unit 322 inserted into the light receiving lens holder 323 so that the light receiving lens unit 322 can be rotated, or fixing the light receiving lens unit 322 to the light receiving lens holder 323 by tightening. It is a tool. The unit fastener 325 is screwed into a screw hole (not shown) formed so as to be orthogonal to the notch 32b of the light receiving lens holder 323.

The holder fastener 326 is a fastening for loosening the light receiving lens holder 323 fitted in the light receiving lens bracket 324 so that the light receiving lens holder 323 can be rotated, or for fastening the light receiving lens 32 to fix the tilt in the front-rear direction. It is a tool. The holder fastener 326 is screwed into the light receiving lens holder 323 through the light receiving lens bracket 324 at the tip.
The bracket fastener 327 is a fastener for attaching the light-receiving lens bracket 324 to the position adjustment hole 301 so as to be movable up and down and rotatable, and is a screw hole (through the position adjustment hole 301 formed in the light-receiving lens bracket 324 ( (Not shown). The bracket fastener 327 can be rotated by loosening the tightening of the light receiving lens bracket 324, and the inclination of the optical axes of the light receiving lens bracket 324 and the light receiving lens 32 can be adjusted.

<Scanning means>
As shown in FIGS. 5 and 6, the scanning unit 33 is a mirror for changing the irradiation direction of the laser light that has passed through the light receiving lens 32, and converts the optical axis of the measurement light that has passed through the light receiving lens 32 by 90 degrees. X-direction galvanometer mirror 33X (first galvanometer mirror) and Y-direction galvanometer mirror 33Y (second galvanometer mirror) that converts the optical axis in a direction that is 90 degrees different from the direction of the optical axis converted by the X-direction galvanometer mirror 33X ).

The laser light emitted from the light source 11 is applied to the sample S (see FIG. 2) via the X-direction galvanometer mirror 33X and the Y-direction galvanometer mirror 33Y, and the nozzle S of the diagnostic probe unit 30 is directly opposed to the sample S. The detector 23 acquires the internal information in the depth direction (A direction) going from the surface to the inside. As will be described later, data in the A direction consisting of 1152 points (hereinafter referred to as A line data) is acquired in one scan, and image processing for subsequent frequency analysis is acquired.

Here, the X direction and the Y direction correspond to the horizontal direction and the vertical direction (Y-axis direction) on the surface of the sample S facing the nozzle tip of the diagnostic probe unit 30.

The X direction galvanometer mirror 33X is provided on the light receiving lens 32 side. The X-direction galvanometer mirror 33X rotates a mirror surface (AV plane) by motor drive with the A direction as an axis. At this time, the direction of the acquired data is data in the horizontal direction (X-axis direction) on the surface of the sample S, and is data in the B direction. If the operation rotation angle of the galvano mirror is, for example, -3 ° to + 3 ° and 128-point B-direction data is required, 128-point B-direction data (hereinafter referred to as B-line data) is acquired as described later. .

The Y-direction galvanometer mirror 33Y is provided on the condensing lens 34 side, and rotates the mirror surface (BV plane) by motor driving around the B direction. At this time, the direction of the acquired data is data in the vertical direction (Y-axis direction) on the surface of the sample S, and is data in the V direction (hereinafter referred to as V line data).

<Condensing lens>
As shown in FIGS. 5 and 6, the condensing lens 34 is a lens that condenses the scanning light from the scanning unit 33 and condenses the measurement light on the sample S and irradiates it. It is installed inside. The lens storage cylinder 352 is disposed in the condensing lens storage portion 3 c of the housing 3 so as to freely advance and retract along the position adjustment hole 302. A ring-shaped operation knob 351 on which a user's finger is loosely fitted is integrally formed on the lower surface portion of the lens housing cylinder 352.

<Condensing point adjustment mechanism>
As shown in FIG. 6, the condensing point adjustment mechanism 35 is a device that adjusts the condensing point by adjusting the distance between the condensing lens 34 and the sample S (subject) in contact with the nozzle 37. The operating knob 351 is exposed in the condensing lens storage portion 3c of the housing 3 in an exposed state. The condensing point adjusting mechanism 35 includes a position adjusting hole 302 extending in the horizontal direction in the horizontal portion 300c of the frame main body 300, and the lens accommodating cylinder 352 inserted along the optical axis by being inserted into the position adjusting hole 302. An adjustment screw 353 that fixes the position adjustment hole 302 formed at an appropriate position and a lens housing cylinder 352 integrally formed to move the condenser lens 34 to an appropriate position of the position adjustment hole 302. The operation knob 351 and a connecting cylinder 354 for fixing the front tooth nozzle 37 </ b> A (nozzle 37) to the frame main body 300 through the nozzle support 36 are provided.
The condensing point adjusting mechanism 35 is configured to adjust the condensing point by operating and moving the operation knob 351 so that the condensing lens 34 moves forward and backward in the optical axis direction together with the operation knob 351.

<Nozzle>
As shown in FIG. 8, the nozzle 37 (front tooth nozzle 37 </ b> A) is a cylindrical member that is disposed in front of the condenser lens 34 and has an opening 37 </ b> Ae that irradiates the sample S with measurement light and collects scattered light. is there. The front tooth nozzle 37 </ b> A is detachable (replaceable) through the condensing lens housing 3 c at the tip of the housing 3 through the connecting cylinder 354, the nozzle support 36, the spring SP, the spherical body SB, and the outer ring member 38. ) And is rotatably mounted.
When imaging the front teeth (sample S) with the diagnostic probe unit 30 (see FIG. 5), the front tooth nozzle 37A abuts the opening 37Ae of the cylindrical front tooth nozzle 37A on the sample S and sets the interval therebetween. This is a member for collecting the reflected scattered light by irradiating the sample S with measurement light while being held.

As shown in FIGS. 7 and 8, the front tooth nozzle 37 </ b> A has an engagement tube portion 37 </ b> Aa for fitting the front tooth nozzle 37 </ b> A to the nozzle support 36 on the base end side, and the engagement tube portion. An annular groove 37Ab that is formed on the outer spherical surface of 37Aa and engages with the sphere SB, a flange portion 37Ac that is locked to the distal end of the engaging cylinder portion 37Aa, and a cylindrical portion 37Ad that extends from the flange portion 37Ac to the distal end side. And are integrally formed.

As shown in FIG. 8, the nozzle support 36 is a substantially cylindrical member that is interposed between the connecting cylinder 354 and the front tooth nozzle 37 </ b> A and is fitted into the outer ring member 38. The nozzle support 36 has an engagement portion 36a fitted in the connecting cylinder 354 on the proximal end side, and an outer ring member 38, and a proximal end side of the spring SP made of a cylindrical coil spring. A spring receiving portion 36b to be supported, a spring exterior portion 36c into which the spring SP is fitted, and a sphere insertion hole 36d into which the sphere SB is movably fitted are formed.

The outer ring member 38 is a substantially cylindrical member that is disposed outside the nozzle support 36 and the spring SP so as to cover the nozzle support 36 and the spring SP, and a spring receiver that supports the tip of the compressed spring SP on the inner surface thereof. A convex portion 38a is formed.

≪Control unit section≫
As shown in FIG. 2, the control unit 50 (control unit) includes an AD conversion circuit 51, a DA conversion circuit 52, a galvano mirror control circuit 53, a display device 54, and an OCT control device 100.

The AD conversion circuit 51 converts the analog output signal of the detector 23 (detector) into a digital signal. In the present embodiment, the AD conversion circuit 51 starts acquisition of a signal in synchronization with a trigger output from the laser output device that is the light source 11, and the timing of the clock signal ck that is also output from the laser output device. At the same time, the analog output signal of the detector (detector) 23 is acquired and converted into a digital signal. This digital signal is input to the OCT controller 100.

The DA conversion circuit 52 converts the digital output signal of the OCT control device 100 into an analog signal. In the present embodiment, the DA conversion circuit 52 converts the digital signal of the OCT control device 100 into an analog signal in synchronization with a trigger output from the laser output device that is the light source 11. This analog signal is input to the galvanometer mirror control circuit 53.

The galvanometer mirror control circuit 53 is a driver that controls the scanning means 33 of the diagnostic probe unit 30. The galvano mirror control circuit 53 drives the motor of the X direction galvano mirror 33X or the Y direction galvano mirror 33Y in synchronization with the output period of the laser emitted from the light source 11 based on the analog output signal of the OCT control device 100. Alternatively, a motor drive signal to be stopped is output (see FIGS. 5 and 6).

The galvano mirror control circuit 53 performs processing for changing the angle of the mirror surface by rotating the axis of the X direction galvano mirror 33X, and processing for changing the angle of the mirror surface by rotating the axis of the Y direction galvano mirror 33Y. It is performed at different timing (see FIGS. 5 and 6). These processes of the galvanometer mirror control circuit 53 are simply referred to as galvanometer mirror X and Y axis changes. An example of timing for changing the galvanometer mirror X and Y axes will be described later.

The display device 54 displays an optical coherence tomographic image (hereinafter referred to as an OCT image) generated by the OCT control device 100. The display device 54 includes, for example, a liquid crystal display (LCD: Liquid Crystal Display), EL (Electronic Luminescence), CRT (Cathode Ray Tube), PDP (Plasma Display Panel), and the like.

The OCT control apparatus 100 is a control apparatus for the OCT apparatus 1 and performs imaging by controlling the scanning unit 33 in synchronization with the laser beam, and also generates an OCT image of the sample S from the data obtained by converting the detection signal of the detector 23. The control which produces | generates is performed. The OCT control apparatus 100 includes a computer including input / output means (not shown), storage means, and arithmetic means, and a program installed in the computer.

[Action]
Next, the case where the sample S (front tooth) is imaged using the OCT apparatus 1 (optical coherence tomographic image generation apparatus) will be described.
After the power switch (not shown) is turned on, the operation button SW (see FIG. 4) is operated to drive the shutter driving means 313 of the shutter mechanism 31 shown in FIG. 6 to open the shutter 312.
When the optical axis is inclined, the holder fastener 326 shown in FIG. 6 is loosened to adjust the inclination in the V direction, and the bracket fastener 327 is loosened to adjust the inclination in the A direction.

The diagnostic probe unit 30 includes a condensing point adjustment mechanism 35 that adjusts the condensing point by adjusting the distance between the condensing lens 34 and the sample S that is in contact with the tip of the nozzle 37 when photographing. By providing the tomographic image, the position of the tomographic image to be photographed can be adjusted in the depth direction from the reference plane of the sample S, and a tomographic image can be obtained over a wide range in the depth direction.

As shown in FIG. 2, the OCT apparatus 1 includes an optical path length changing unit 24 that changes the optical path length from the coupler 12 (optical divider) to the reference mirror 21 by moving the collimator 19d in the optical axis direction. A condensing point adjusting mechanism 35 that adjusts the condensing point by adjusting the distance between the condensing lens 34 and the sample S, and by operating both to make the optical path lengths coincide with each other. A clear tomographic image within a coherent distance can be obtained.

Next, the coherence distance of highly coherent light will be described.
The conventionally used OCT apparatus 1 shown in Table 1 has a coherence distance of 6 mm. When the coherence distance was 6 mm, the imageable range was shallow, and data could not be taken over a wide range in the depth direction. The coherence distance is better when the data in the depth direction in the optical axis direction is deeper in order to photograph a tooth-specific thing (such as caries).
When the coherence distance is 48 mm or more, the wavelength of light emitted from the light source is raised on the stairs, and the power supply becomes complicated. In addition, the light source becomes large and it is difficult to downsize. Furthermore, the shooting speed is slow and camera shake is likely to occur.
Therefore, in the present invention, although the resolution is inferior to that of the coherence distance of 6 mm, more data in the depth direction can be acquired, the photographing speed is fast, and the effect of using the coherence distance of 14 mm is actually used. confirmed.

The OCT apparatus 1 can theoretically be equipped with a light source having a coherence distance of 48 mm or more for highly coherent light, but this light source sweeps the wave number (wavelength) stepwise. Since the OCT method is used, if the overall performance including the sweep speed and resolution is obtained from this light source, it becomes difficult to manufacture the light source itself, so the coherence distance is set to less than 48 mm.
For this reason, the coherent distance is suitably 10 mm or more and less than 48 mm.

≪First modification≫
The present invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the technical idea. The present invention extends to these modifications and changes. Of course. In addition, the already demonstrated structure attaches | subjects the same code | symbol and abbreviate | omits the description.
FIG. 9 is a diagram showing a first modified example of the optical coherence tomographic image generation device according to the embodiment of the present invention, and is an exploded perspective view of a main part of a diagnostic probe unit.

In the above embodiment, the condensing point adjusting mechanism 35 for manually moving the operation knob 351 in the optical axis direction has been described (see FIG. 6), but the present invention is not limited to this. The condensing point adjustment mechanism 35A moves the condensing lens 34A in the direction of the optical axis of the measurement light by the electric motor 35Ab, like the diagnostic probe unit 30A shown in FIG. It may be an electric condensing lens moving mechanism 35Aa that adjusts the distance.

In this case, the condensing lens moving mechanism 35Aa of the condensing point adjusting mechanism 35A includes a lens case 35Ac that houses the condensing lens 34A so as to be movable in the optical axis direction, and an ultrasonic linear actuator that advances and retracts the lens case 35Ac in the axial direction. And a guide member 35Ad for guiding the movement of the electric motor 35Ab that moves integrally with the lens case 35Ac. The condensing lens moving mechanism 35Aa moves the condensing lens 34A to change the focal position, thereby enabling focusing on a position deeper than the tip of the diagnostic probe unit 30A.

The lens case 35Ac is made of, for example, a substantially cylindrical member that houses the condenser lens 34A, and is arranged with the center line aligned with the optical axis. The lens case 35Ac is screwed to the electric motor 35Ab. The lens case 35Ac may be moved in the optical axis direction with respect to the frame main body 300 by the electric motor 35Ab, and is not limited to the one that moves the electric motor 35Ab integrally.

The electric motor 35Ab is driven by operating the operation button SW (see FIG. 4), and is guided by the rail portion 35Ae of the guide member 35Ad so as to advance and retreat in the optical axis direction. The electric motor 35Ab is not limited to the ultrasonic linear actuator, and may move the lens case 35Ac via a gear reduction mechanism or the like.
The guide member 35Ad includes, for example, a pair of rail portions 35Ae that guide the movement of the electric motor 35Ab, and a holder base 34Af that holds the rail portions 35Ae and is fixed to the frame body 300.

≪Second modification≫
FIG. 10 is a diagram showing a second modification of the optical coherence tomographic image generation apparatus according to the embodiment of the present invention, and is a perspective view of a diagnostic probe unit. FIG. 11 is a diagram showing a second modification of the optical coherence tomographic image generation apparatus according to the embodiment of the present invention, and is an exploded perspective view of a main part of a diagnostic probe unit. FIG. 12 is a diagram showing a second modification of the optical coherence tomographic image generation apparatus according to the embodiment of the present invention, and is a middle longitudinal sectional view of the diagnostic probe section. FIG. 13 is a view showing a second modification of the optical coherence tomographic image generation apparatus according to the embodiment of the present invention, and is an enlarged vertical cross-sectional view of a main part showing a nozzle installation state.

In the above-described embodiment, as an example of the OCT apparatus 1, the front teeth (incisors) are the sample S, and the diagnostic probe unit 30 including the straight type front tooth nozzle 37A illustrated in FIGS. 4 and 5 is described as an example. However, the present invention is not limited to this.
As shown in FIGS. 10 to 13, the diagnostic probe unit 30B may be used by replacing the sample S with an angle-type molar nozzle 37B with the molar as a molar.

In this case, the molar nozzle 37 </ b> B has an oblique mirror 37 </ b> Ba for converting the optical axis of the condenser lens 34 in a direction orthogonal to the distal end inner wall 37 </ b> Bc of the cylindrical portion 37 </ b> Bb and orthogonal to the optical axis of the condenser lens 34. An opening 37Bd is formed in the direction in which the light is scattered, and the sample S in a direction orthogonal to the longitudinal direction of the molar nozzle 37B is irradiated to collect scattered light. The molar nozzle 37B is detachably (replaceable) and rotatably mounted on the housing 3 in the same manner as the front tooth nozzle 37A.

The molar nozzle 37B irradiates the sample S with measurement light while maintaining the interval by bringing the opening 37Bd of the molar nozzle 37B into contact with the sample S (molar) when imaging the molar with the diagnostic probe unit 30B. Then, the reflected scattered light is collected.
As shown in FIG. 13, the molar nozzle 37 </ b> B includes a hollow engaging cylinder portion 37 </ b> Be for fitting the molar nozzle 37 </ b> B into the nozzle support 36 on the proximal end side, and the engaging cylinder portion. An annular groove 37Bf that is formed on the outer surface of 37Be and engages with the sphere SB, a flange portion 37Bg formed on the distal end side of the engagement tubular portion 37Be, and a cylinder that extends from the flange portion 37Bg toward the distal end side The portion 37Bb, the tip end inner wall 37Bc where the oblique mirror 37Ba is disposed obliquely, and the opening 37Bd opened below the tip end inner wall 37Bc are integrally formed.

Thus, the molar nozzle 37B includes the oblique portion 37Ba for converting the optical axis by 90 degrees and the opening portion 37Bd opened in the direction orthogonal to the distal end of the tubular portion 37Bb by the tubular portion 37Bb. Is rotated, the direction of the opening 37Bd (the direction in which the image is taken) can be freely changed, so that the molars in the back of the oral cavity can be easily imaged.

<< Third Modification >>
FIG. 14 is a diagram showing a third modification of the optical coherence tomographic image generation device according to the embodiment of the present invention, and is an exploded perspective view of a main part of a diagnostic probe unit provided with a nozzle expansion / contraction mechanism. FIG. 15 is a diagram showing a third modification of the optical coherence tomographic image generation device according to the embodiment of the present invention, and is an enlarged vertical sectional view of a main part of a diagnostic probe unit provided with a nozzle expansion / contraction mechanism. FIG. 16 is a diagram showing a third modification of the optical coherence tomographic image generation device according to the embodiment of the present invention, and is a perspective view of the main part of the optical path length changing means.

A third modified example of the optical coherence tomographic image generation device according to the embodiment of the present invention, as shown in FIGS. 14 and 15, instead of the above-described focusing point adjustment mechanism 35 (see FIGS. 5 and 6), The nozzle 37C is advanced or retreated, or the nozzle length L1 is changed to adjust the distance between the condenser lens 34 and the sample S, and the optical path length of the reference light shown in FIG. And optical path length changing means for changing.

<Nozzle extension mechanism>
The nozzle expansion / contraction mechanism 39 forms a condensing point adjustment mechanism that adjusts the distance between the condensing lens 34 and the sample S by moving the nozzle 37 </ b> C forward and backward with respect to the housing 3.

In this case, the nozzle 37C of the diagnostic probe section 30C (probe) includes a nozzle base 37C1 that is detachably fitted to the tip of the nozzle support 36, and a nozzle expansion / contraction that is attached to the nozzle base 37C1 in a stretched state. And a body 37C2.
The nozzle base 37C1 has a female thread portion 37Ca formed in the opening at the tip.
The nozzle expandable body 37C2 has a male screw portion 37Cb that is screwed into the female screw portion 37Ca on the outer peripheral surface on the base end side, and the nozzle length L1 is set to a desired length by rotating and reversing the nozzle expandable body 37C2. The distance between the condenser lens 34 and the sample S can also be adjusted.

<Optical path length changing means>
As shown in FIG. 16, the optical path length changing means 24 arranges a collimator lens unit 19 ′ (see FIG. 3) movably in the optical axis direction with respect to the support base 191, and moves the collimator lens unit 19 ′. Thus, the optical path length from the coupler 12 (light splitter) to the reference mirror 21 is changed. Therefore, the difference will be mainly described while comparing with the collimator lens unit 19 ′ in FIG.
The optical path length changing means 24 includes a bracket 19h on which a collimator holder 19e that holds the collimator 19d is mounted, and a lens moving device 195 that moves the bracket 19h in the optical axis direction.

The lens moving device 195 mainly includes an actuator 196, an actuator support 198 fixed to the support base 191, and a rail member 197 that guides when the actuator 196 moves.
The actuator 196 is composed of, for example, an electric device such as an ultrasonic linear actuator, and moves in the optical axis direction relative to the slidably supported actuator support 198 by operating a control switch (not shown). ing.
The actuator support 198 is a guide member that guides and supports the movement of the lens moving device 195, and places the bracket 19h slidably in the optical axis direction.

With such a configuration, the optical coherence tomographic image generation device according to the third modification of the present invention includes the optical path length changing unit that changes the optical path length from the optical splitter to the reference mirror, so that the subject can be controlled by the nozzle expansion / contraction mechanism. Even when the optical path length from the optical multiplexer to the optical multiplexer is changed, the optical path lengths of the scattered light and the reflected light can be matched, so that the analysis of the interference light can be easily performed.

The tomographic image photographed by the diagnostic probe unit 30C shown in FIGS. 14 and 15 is inverted when the nozzle 37C is expanded and contracted, the target point of the image to be photographed is moved and passed through the focal position. The reversal of the tomographic image can be avoided by moving the reference light side collimator 19d shown in FIG. The tomographic image appears so that a part of the tomographic image is folded by changing the focal position. In order to prevent this, the collimator 19d on the reference light side is moved. The same thing as the collimator 19d on the reference light side also occurs in the diagnostic probe unit 30C. However, since the space inside the probe is limited, it is desirable that the probe be performed on the reference light side.

1 OCT device (optical coherence tomographic image generator)
11 Light source 12 Coupler (light splitter)
16 coupler (optical multiplexer)
DESCRIPTION OF SYMBOLS 19 Collimator lens 19d Collimator 20 Reference light condensing lens 21 Reference mirror 24 Optical path length change means 30, 30A, 30B, 30C Diagnostic probe part (probe)
31 Shutter mechanism 32 Light receiving lens 33 Scanning means 34 Condensing lens 35, 35A Condensing point adjustment mechanism 35Aa Condensing lens moving mechanism 37 Nozzle 39 Nozzle expansion / contraction mechanism L1 Nozzle length S Sample (subject)

Claims (6)

1. A light source that periodically irradiates laser light of a high-band wavelength;
   An optical splitter for distributing the measurement light for irradiating the subject with the laser light and the reference light for irradiating the reference mirror;
   A probe that irradiates the subject with the measurement light and receives scattered light that is scattered and returned inside the subject;
   An optical multiplexer that generates interference light by combining the reflected light that is reflected from the reference mirror and returned from the reference mirror, and that generates interference light. An optical coherence tomographic image generation device for generating an image,
   The laser light is highly coherent light having a coherence distance of 10 mm or more,
   The probe includes a condensing lens that condenses the measurement light on the subject;
   A condensing point adjusting mechanism for adjusting a condensing point by adjusting a distance between the condensing lens and the subject;
   An optical coherence tomographic image generation apparatus comprising:
2. The condensing point adjusting mechanism includes a condensing lens moving mechanism that adjusts a distance between the condensing lens and the subject by moving the condensing lens in an optical axis direction of the measurement light. The optical coherence tomographic image generation apparatus according to claim 1.
3. The probe has a nozzle that is attached to the tip of the probe and makes contact with the subject,
   2. The condensing point adjusting mechanism includes a nozzle expansion / contraction mechanism that adjusts a distance between the condensing lens and the subject by moving the nozzle back and forth or changing a nozzle length. The optical coherence tomographic image generation apparatus according to claim 2.
4. A collimator that converges the reference light split by the light splitter into parallel light;
   A reference light condensing lens that condenses the parallel light converged by the collimator on the reference mirror;
   An optical path length changing means for changing the optical path length from the optical splitter to the reference mirror by moving the collimator in the optical axis direction;
   The optical coherence tomographic image generation apparatus according to claim 3, further comprising:
5. 3. The optical coherent tomographic image generation apparatus according to claim 1, wherein a coherent distance of the highly coherent light is less than 48 mm.
6. Laser light emitted from a light source is distributed to measurement light that irradiates a subject and reference light that is emitted to a reference mirror, and interference light obtained by combining scattered light reflected from the subject and reflected light from the reference mirror An optical coherence tomographic image generation method for analyzing and diagnosing,
   The laser light uses a highly coherent light whose coherence distance is 10 mm or more and less than 48 mm,
   Adjusting a distance between a condensing lens for condensing the measurement light on the subject and the subject and adjusting a condensing point within a coherent range with respect to the coherent distance to obtain an optical coherence tomographic image; An optical coherence tomographic image generation method.

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