JPWO2014157645A1 - Laser scanning observation apparatus and laser scanning method - Google Patents

Abstract

  A window portion that is provided in a partial region of the housing and that is in contact with or close to the observation target; an objective lens that focuses laser light on the observation target through the window portion; and the laser that has been guided in the housing An optical path changing element that changes the traveling direction of light toward the window portion, and a non-astigmatism that is provided upstream of the window portion and corrects astigmatism that occurs when the laser light is focused on the observation target. A point aberration correction element, and a rotation mechanism that rotates at least the optical path changing element with a rotation axis perpendicular to the direction of incidence of the laser light on the window portion so that the laser light scans the observation target. The astigmatism correction element includes a correction amount corresponding to a change in astigmatism accompanying a change in observation depth, which is a depth of the condensing position of the laser beam in the observation target. Correcting the difference, to provide a laser-scanning examination apparatus.

Description

  The present disclosure relates to a laser scanning observation apparatus and a laser scanning method.

  As a technique for observing an object with high resolution, there is a laser scanning microscope apparatus. In a laser scanning microscope apparatus, an object is irradiated with laser light, and the laser light is scanned on the object, while transmitting light, backscattered light, fluorescence, Raman scattered light, and various types of light generated by nonlinear optical effects. By detecting the intensity such as, it is possible to acquire various information related to the object as two-dimensional or three-dimensional image data. In recent years, the technique of the laser scanning microscope apparatus has been applied to a probe that is brought into contact with the body surface of a subject (patient), an endoscope that is inserted into the body cavity of the subject, and the like. Attempts have been made to observe biological tissue of (patient) with higher resolution.

  Here, in a microscope apparatus, an endoscope apparatus, a probe, etc. (hereinafter collectively referred to as a laser scanning observation apparatus) that observes an object by scanning the laser beam as described above, an observation object (for example, a living body). There is a demand to view a wide range of tissue) and to enlarge and observe any part as necessary. That is, a laser scanning observation apparatus is required to have both a wide field of view (actual field of view (FOV)) and a high numerical aperture (NA). However, in general, in order to achieve both a wide FOV and a high NA, it is necessary to configure a complicated optical system, and there is a concern about an increase in size and cost of the apparatus. In particular, in a device such as a probe or an endoscope device that is required to be relatively small for its application, it is difficult to mount a complicated optical system, and a configuration that achieves both a wide FOV and a high NA. It was difficult to realize.

  On the other hand, in the field of so-called optical coherence tomography (OCT: Optical Coherence Tomography), which obtains a tomographic image of biological tissue using light interference, by providing a rotation mechanism in the optical element in the head portion of the endoscope, An endoscope apparatus that realizes a reduction in the size of the head portion has been proposed. For example, in Non-Patent Document 1, by irradiating a living tissue with low coherence light while rotating a green lens and a prism provided in a head portion of an endoscope with the longitudinal direction of the lens barrel as a rotation axis direction, An OCT system capable of acquiring a tomographic image of the living tissue is disclosed. Further, for example, Non-Patent Document 2 uses OCT, in which, as in Non-Patent Document 1, an observation image is obtained by rotating a grind lens and a mirror provided in the head unit with the longitudinal direction of the lens barrel as the rotation axis direction. In the conventional endoscope apparatus, by forming the reflecting surface of the mirror in a shape that corrects astigmatism that may occur in the data acquisition (image capturing) window provided on the side wall of the lens barrel, A technique for obtaining a higher-quality observation image is disclosed. There is a possibility that a wide FOV can be realized by applying the rotation mechanism of the optical element as described in Non-Patent Documents 1 and 2 to the laser scanning observation apparatus.

  Based on such knowledge, a technique for realizing a wide FOV by rotating an optical element in a head portion of an endoscope and scanning a laser beam in a circumferential direction of the barrel has been proposed. For example, Non-Patent Document 3 discloses an endoscope in which laser light guided in a lens barrel by an optical fiber is condensed on a mirror by a green lens, and light is irradiated to a living tissue existing in the side surface direction of the lens barrel. In the apparatus, there is disclosed a laser scanning endoscope apparatus that acquires image data by scanning a laser beam in a circumferential direction of the lens barrel by rotating the mirror with the longitudinal direction of the lens barrel as a rotation axis direction. Yes. Further, for example, Non-Patent Document 4 discloses an endoscope in which laser light guided in a lens barrel by an optical fiber is diffracted by a grating in the side surface direction of the lens barrel, and light is irradiated to a living tissue via an objective lens. In the mirror apparatus, a laser scanning endoscope apparatus that acquires image data by scanning the laser beam in the circumferential direction of the lens barrel by rotating the grating and the objective lens with the longitudinal direction of the lens barrel as the rotation axis direction. Is disclosed.

Guillermo J.M. Teaney et al. "In Vivo Endoscopic Optical Biopsy with Optical Coherence Tomography", Science 1997 Vol. 276 p. 2037-2039 Jiefeng Xi et al. , “High-resolution OCT balloon imaging catalyst with astigmatism correction”, OPTICS LETTERS 2009 Vol. No. 34 13 p. 1943-1945 Gangjun Liu et al. "Rotational multiphoton endoscopy with a 1 μm fiber laser system", OPTICS LETTERS 2009 Vol. No. 34 15 p. 2249-2251 D. Yelin et al. , “Large area confocal microscopy”, OPTICS LETTERS 2007 Vol. 32 No. 9 p. 1102-1104

  On the other hand, in the laser scanning observation apparatus, in order to acquire image data of a desired part more stably, an image data acquisition (image capturing) window part provided in a part of the casing is used as an observation target. A method of use in which observation is performed by condensing a laser beam on an observation target through the window portion by an objective lens while being brought into contact with each other is conceivable. When using such a usage method, from the viewpoint of safety, the window portion in contact with the observation target is required to have a predetermined thickness in order to ensure a predetermined strength.

  Here, considering the aberration that occurs when the observation target is irradiated with the laser beam condensed by the objective lens, the higher the NA of the objective lens, the thicker the window portion, The degree of aberration tends to increase. In addition, when the window portion is provided on the side wall of a cylindrical housing such as a lens barrel of an endoscope and has a cylindrical shape (cylindrical shape) in accordance with the shape of the housing, the curvature of the window portion It is considered that the degree of aberration is further increased as the lens becomes smaller (that is, as the diameter of the lens barrel as the housing becomes smaller). In particular, when laser light passes through a window portion having a cylindrical surface, aberration (particularly astigmatism) occurs even on the optical axis, and the quality of acquired image data may deteriorate.

  Further, in the laser scanning observation apparatus, there is a demand for acquiring images of a plurality of layers (layers) by performing laser scanning while changing the observation depth (that is, the irradiation depth of the laser light on the observation target). . If the observation depth is changed, the convergence state and divergence state of the laser light when passing through the objective lens and the window portion also change, so the degree of aberration also changes. In order to acquire a high-quality observation image, it is necessary to design the optical system in consideration of such a change in aberration caused by changing the optical system during observation.

  However, the techniques described in Non-Patent Documents 1 and 2 relate to OCT, and an objective lens having a relatively low NA (for example, NA≈0.1) is used. Aberrations are not a big problem. Nevertheless, in the technique described in Non-Patent Document 2, the image quality is improved by correcting the aberration according to the shape of the mirror. However, in this method, as described above, for example, the observation depth is changed, and the aberration is reduced. It cannot cope with the case where the degree changes. Further, in the technologies described in Non-Patent Document 2 and Non-Patent Document 3, the detailed configuration of the window part is not mentioned, and therefore, the conditions required for the window part from the above safety viewpoint, The aberration caused by the configuration of the window portion has not been taken into consideration. Thus, in a conventional endoscope apparatus, while using an objective lens having a relatively high NA, safety is ensured by providing a predetermined thickness in the window portion, and the influence of aberration is suppressed. Therefore, it is difficult to achieve both high-accuracy observation.

  Therefore, the present disclosure proposes a new and improved laser scanning observation apparatus and laser scanning method capable of performing observation with higher accuracy.

  According to the present disclosure, a window portion that is provided in a partial region of the housing and that is in contact with or close to the observation target, an objective lens that focuses the laser light on the observation target through the window portion, and the inside of the housing are guided. An optical path changing element that changes a traveling direction of the laser light that has been emitted toward the window portion, and a non-path that is provided before the window portion and that is generated when the laser light is focused on the observation target. An astigmatism correction element that corrects astigmatism, and at least the optical path changing element at a rotation axis perpendicular to the incident direction of the laser light to the window portion so that the laser light scans the observation object. The astigmatism correction element corresponding to a variation in astigmatism accompanying a change in observation depth, which is a depth of the laser beam condensing position in the observation target. Positive amount to correct the astigmatism, the laser-scanning examination apparatus is provided.

  Further, according to the present disclosure, laser light is incident on an optical path changing element provided inside the casing, and a traveling direction of the laser light guided in the casing by the optical path changing element is changed. The laser beam focused on by an objective lens and corrected for astigmatism by an astigmatism correction element via a window portion provided in a partial region of the housing and in contact with or close to the observation target is observed. Irradiating the target, and at least the optical path changing element at a rotation axis perpendicular to an observation direction that is an incident direction of the laser light to the observation target so that the laser light scans the living tissue. The astigmatism correction element includes a correction amount corresponding to a change in astigmatism accompanying a change in observation depth, which is a depth of the condensing position of the laser beam in the observation target. Concerned To correct astigmatism, the laser scanning method is provided.

  According to the present disclosure, the laser light is scanned with respect to the observation target by rotating at least the optical path changing element in the housing. Therefore, the range in which the laser beam is scanned on the observation target while the optical path changing element rotates once is secured as the FOV, so that a wide field of view is realized even when the NA of the objective lens is relatively high. In addition, since an astigmatism correction element that corrects the astigmatism with a correction amount corresponding to the change in astigmatism accompanying the change in the observation depth is provided, the observation depth is changed. However, it is possible to perform highly accurate observation with less astigmatism.

  As described above, according to the present disclosure, more accurate observation can be performed. Note that the above effects are not necessarily limited, and any of the effects shown in the present specification, or other effects that can be grasped from the present specification, together with or in place of the above effects. May be played.

It is a graph which shows the relationship between NA and FOV about the existing laser scanning type endoscope apparatus. It is a graph which shows the relationship between the size of a head part, NA, and FOV about the existing laser scanning endoscope. 1 is a schematic diagram illustrating a configuration example of a laser scanning endoscope apparatus according to a first embodiment of the present disclosure. It is the schematic which shows typically the structure of the scanning part shown in FIG. It is a schematic diagram showing an example of 1 composition of a laser scanning endoscope apparatus concerning a 2nd embodiment of this indication. It is the schematic which shows the mode of the cross section of a multi-core optical fiber. It is the schematic which shows one structural example of the laser scanning type endoscope apparatus in case a scanning part has two or more objective lenses. It is the schematic which shows one structural example of the scanning part in case an optical path change element is a polarization beam splitter. It is the schematic which shows a mode when the scanning part shown to FIG. 6A rotates 180 degree | times by making the y-axis into a rotating shaft. It is the schematic which shows one structural example of the scanning part in case an optical path change element is a MEMS mirror. It is the schematic which shows one structural example of the scanning part in case an optical path change element is a MEMS mirror. It is the schematic which shows one structural example of the scanning part in case a scanning part has an optical path branching element. It is the schematic which shows one structural example of the scanning part in case a scanning part has an optical path branching element. It is the schematic which shows one structural example of the scanning part in case the incident position of the laser beam with respect to a lens barrel is fixed. It is the schematic which shows one structural example of the scanning part in case the incident position of the laser beam with respect to a lens barrel is fixed. It is the schematic which shows one structural example of the endoscope in which a scanning part has a different rotating shaft direction. It is the schematic which shows typically the structure of the scanning part shown to FIG. 10A. It is the schematic which shows the example of 1 structure of the endoscope which concerns on the modification by which a some objective lens is arranged in the longitudinal direction of a lens-barrel. It is the schematic which shows the other structural example of the endoscope which concerns on the modification by which a some objective lens is arranged in the longitudinal direction of a lens-barrel. It is a schematic diagram which shows the structure of the cylindrical uneven | corrugated lens pair which is one structural example of the aberration correction element which concerns on this embodiment. It is a schematic diagram which shows the structure of the cylindrical uneven | corrugated lens pair which is one structural example of the aberration correction element which concerns on this embodiment. It is a schematic diagram which shows the structure of the cylindrical meniscus lens which is one structural example of the aberration correction element which concerns on this embodiment. It is a schematic diagram which shows the structure of the cylindrical plano-convex lens which is one structural example of the aberration correction element which concerns on this embodiment. It is explanatory drawing for demonstrating the observation depth adjustment mechanism in the laser scanning endoscope apparatus which concerns on this embodiment. It is a figure which shows an example of the laser scanning method using the observation depth adjustment mechanism in the laser scanning endoscope apparatus which concerns on this embodiment. It is a side view which shows the example of 1 structure of the laser scanning probe which concerns on this embodiment. It is a figure which shows arrangement | positioning of the optical member in the laser scanning probe shown in FIG. It is a figure which shows arrangement | positioning of the optical member in the laser scanning probe shown in FIG. It is a figure which shows arrangement | positioning of the optical member in the laser scanning probe shown in FIG. It is explanatory drawing for demonstrating the parameter which affects astigmatism in the optical system of a laser scanning probe. It is a graph which shows an example of the optical characteristic of the cylindrical meniscus lens used as an astigmatism correction element in this embodiment. It is a graph which shows the observation depth dependence of the astigmatism of the optical member which has a curved surface of 2 surfaces, and the optical member which has a curved surface of 1 surface. It is explanatory drawing for demonstrating the chromatic aberration correction element applied to a laser scanning probe. It is a graph which shows the condensing efficiency of the fluorescence to the optical fiber in the case where a chromatic aberration correction element is applied and the case where it is not applied. It is a perspective view which shows the structure of the handheld laser scanning probe which is another structural example of the laser scanning probe which concerns on this embodiment. It is the schematic which shows the example of 1 structure of the laser scanning microscope apparatus which concerns on this embodiment. It is a block diagram for demonstrating the hardware constitutions of the laser scanning observation apparatus which concerns on this embodiment.

  Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

The description will be made in the following order.
1. 1. Examination of laser scanning endoscope apparatus with other configurations 1. First embodiment Second Embodiment 4. Modified example 4-1. Configuration in which scanning unit includes a plurality of objective lenses 4-1-1. Configuration in which the optical path changing element is a polarization beam splitter 4-1-2. Configuration in which optical path changing element is MEMS mirror 4-1-3. Configuration in which scanning unit includes optical path branching element 4-1-4. Configuration in which the incident position of laser light on the lens barrel is fixed 4-2. Other configuration 4-2-1. Configuration in which scanning unit has rotating shafts in different directions 4-2-2. 4. Modification in which a plurality of objective lenses are arranged in the longitudinal direction of the lens barrel 5. Configuration of aberration correction element 5-1. Correction of astigmatism 5-1-1. Cylindrical uneven lens pair 5-1-2. Cylindrical meniscus lens 5-1-3. Cylindrical plano-concave lens Configuration including observation depth adjustment mechanism 6-1. Laser scanning using observation depth adjustment mechanism 6-2. Laser scanning probe 6-2-1. Overall configuration 6-2-2. Astigmatism correction element 6-2-3. Chromatic aberration correction element 6-2-4. Other configuration examples of laser scanning probe 6-3. 6. Laser scanning microscope apparatus Hardware configuration Summary

  In the following description, an example of a laser scanning observation apparatus according to an embodiment of the present disclosure from (1. Examination of laser scanning endoscope apparatus having other configurations) to (5. Configuration of aberration correction element) will be described. As an example, a laser scanning endoscope apparatus will be described as an example, and its configuration and possible modifications will be described. However, the present disclosure is not limited to such an example, and the laser scanning observation apparatus according to the present embodiment may have other configurations such as a laser scanning probe and a laser scanning microscope apparatus. The matters described in (1. Examination of laser scanning endoscope apparatus with other configurations) to (5. Configuration of aberration correction element) are other configurations such as a laser scanning probe and a laser scanning microscope apparatus. The same applies to the above. An example of a specific configuration of the laser scanning probe or the laser scanning microscope apparatus will be described in detail in (6-2. Laser scanning probe) and (6-3. Laser scanning microscope apparatus).

  Further, as a preferred embodiment of the present disclosure, the laser scanning observation apparatus may include an observation depth adjustment mechanism for adjusting an observation depth, which is a depth at which laser light is condensed on an observation target. Good. Since the laser scanning observation apparatus has an observation depth adjustment mechanism, it is possible to acquire information in the depth direction of the observation target, so that useful observation that meets the demands of the operator (user) can be performed. It becomes possible. Therefore, in this specification, the configuration of the laser scanning observation apparatus having the observation depth adjustment mechanism will be described in detail in (6. Configuration including the observation depth adjustment mechanism). Finally, an example of a hardware configuration capable of realizing the laser scanning observation apparatus according to the present embodiment will be described in (7. Hardware configuration).

  Specifically, (6. Configuration including observation depth adjustment mechanism) is realized by using an observation depth adjustment mechanism in (6-1. Laser scanning using observation depth adjustment mechanism). A laser scanning method will be described. Next, in (6-2. Laser scanning probe), the configuration of a laser scanning probe including an observation depth adjusting mechanism will be described as an example of a configuration different from the endoscope described so far, and the observation depth will be described. The configuration of the adjustment mechanism and the aberration correction element corresponding to the observation depth being changed will be described in detail. Finally, in (6-3. Laser scanning microscope apparatus), as an example of still another configuration of the laser scanning observation apparatus according to the present embodiment, a configuration of a laser scanning microscope apparatus including an observation depth adjustment mechanism is described. explain. The configurations of the laser scanning probe and the laser scanning microscope apparatus described in (6-2. Laser scanning probe) and (6-3. Laser scanning microscope apparatus) are the same as those in the case where an observation depth adjustment mechanism is provided. Although it corresponds to an example, the configuration of the laser scanning probe and the laser scanning microscope apparatus is not limited to this example, and the observation depth adjustment mechanism is not necessarily provided. The laser scanning probe and the laser scanning microscope apparatus according to the present embodiment can take various configurations described by taking a laser scanning endoscope apparatus as an example in this specification.

(1. Examination of laser scanning endoscope device with other configuration)
First, in order to make the present disclosure clearer, the contents examined by the present inventors for a laser scanning endoscope apparatus having another existing configuration will be described.

  The performance required for the laser scanning endoscope device includes the following performances. That is, “1. Depth of penetration”, “2. Miniaturization of head”, “3. High NA”, “4. Wide field of view”, and “5. High-speed scanning”.

  “1. Depth of penetration” is an index that represents an observable distance in the depth direction of a biological tissue that is an observation target. If the depth of penetration is large, it is possible to observe not only the surface of the living tissue but also a deeper position, so that more information about the living tissue can be acquired. Specifically, the depth of penetration can be increased by increasing the working distance (distance to the focal point of the objective lens in the living tissue) by the objective lens arranged to face the living tissue. In addition, it is preferable to provide a mechanism (hereinafter also referred to as an observation depth adjustment mechanism) that has a depth of a predetermined size and can change the observation depth within the range of the depth of penetration. . If the observation depth is variable, for example, by acquiring the observation image while changing the observation depth, it is possible to obtain an image of a plurality of layers in the depth direction and to acquire more information. Become.

  “2. Miniaturization of the head portion” is required from the viewpoint of minimally invasive medical treatment. Considering the physical burden on the patient, it is desirable that the diameter of the head part at the tip of the lens barrel of the endoscope be several mm or less. However, this performance is particularly required in an endoscope. In the case of the laser scanning probe or laser scanning microscope apparatus according to the present embodiment, a lens barrel (housing) having a diameter exceeding 10 mm or larger may be used.

  “3. High NA” is required to acquire an image with high resolution (resolution). By using an objective lens having a high NA, an image with particularly high resolution in the depth direction can be acquired. In the field of OCT, the NA of the objective lens may be about 0.1. However, in order to obtain a high-resolution image as a laser scanning endoscope, the NA of the objective lens is, for example, 0.5. It is desirable that the degree is more than about.

  “4. Wide field of view” is required in order to oversee a wide range of biological tissue as an observation target. The field of view here may be a so-called real field of view (FOV), and may be a range of lines in which laser light is scanned. If the above-mentioned “3. High NA” and “4. Wide field of view” can be compatible, an image with high resolution can be acquired while scanning a wide range. As a visual field, it is desirable that FOV is about 1.0 mm or more, for example.

  “5. High-speed scanning” is required for observing a moving biological tissue. This is because if the scanning speed (scanning speed) is low, it takes a long time to acquire the image data, so that it is difficult to accurately capture the movement of the living tissue. The scan speed is preferably at least 1 fps (frame per sec), for example, and ideally about 30 fps, which is the same as a general video rate.

  The present inventors have examined an existing laser scanning endoscope apparatus from the viewpoint of the above five performances.

  For example, Montana State Univ. Have developed a MEMS mirror type laser scanning endoscope apparatus (see, for example, Christopher L. Arrasmith et al., “MEMS-based handheld confocal microscope in-vivo in-vivo). "OPTICS EXPRESS 2010 Vol.18 NO.4 p.3805-3819). In this case, by using a small mirror formed by MEMS as a device for scanning a laser beam, it is possible to realize both “2. Downsizing of head portion” and “5. High-speed scanning”.

  In addition, for example, Washington Univ. Have developed a fiber end scanning type laser scanning endoscope apparatus (for example, Cameron M. Lee et al., “Scanning fiber endoscopic with high flexures, 1 mm capes). wide-color imaging "Journal of BIOPHOTICS 2010 Vol. 3 NO. 5-6 p. 385-407). This is because the tip of the optical fiber that guides the laser beam is moved two-dimensionally and the living tissue is scanned with the laser beam, so that “2. Miniaturization of the head” and “5. High-speed scanning”. To achieve both.

  Further, for example, a fiber bundle contact type laser scanning endoscope apparatus has been developed by Mauna Kea Technologies. In this method, an optical fiber that guides laser light in a lens barrel of an endoscope is configured in a bundle shape, and the laser light is scanned by light emitted from the fiber bundle. In this method, since a field of view corresponding to the size of the bundle diameter can be secured, it is possible to simultaneously realize “2. Head size reduction”, “4. Wide field of view”, and “5. High-speed scanning”. It becomes possible. In addition, the company has also proposed a laser scanning endoscope apparatus having a configuration in which an objective lens is provided at the tip of the bundle contact type fiber bundle.

  In addition, for example, a research group such as Fraunhofer Institute for Biomedical Technology (IBMT) has developed an actuator-type laser scanning endoscope apparatus (for example, R. Le Harzic et al., “Nonlinear optical endoscopy”). a compact two axes piezo scanner and a miniature objective lens "OPTICS EXPRESS 2008 Vol.25 NO.16 p.20588-20596). This achieves both “3. high NA” and “4. wide field of view” by moving the whole optical system including the objective lens two-dimensionally and scanning the living tissue with laser light. Is.

  Here, in general, in a laser scanning endoscope apparatus having an existing configuration, it is possible to simultaneously realize “2. head size reduction”, “3. high NA”, and “4. wide field of view”. It is considered difficult. This is because a lens having a high NA generally has a high magnification, so that its FOV is low. Here, in the case of a laser scanning microscope apparatus, since the lens barrel diameter is relatively large and a large-scale configuration can be provided therein, the degree of freedom in designing the optical system is high. It is possible to achieve both “NA” and “4. Wide field of view”. For example, if FOV × NA is defined as a performance index representing the performance of the microscope apparatus and the endoscope apparatus, there is a laser scanning microscope apparatus having approximately FOV × NA = 1.0. However, if a large off-axis characteristic is to be ensured, the number of lenses inevitably increases, so that the configuration of the optical system becomes large and complicated, and it is difficult to achieve downsizing and cost reduction. For example, in a laser scanning endoscope apparatus that requires a size of several millimeters for the lens barrel diameter, it is difficult to configure a complicated optical system in the lens barrel, and “2. It is considered difficult to simultaneously realize “3. High NA” and “4. Wide field of view”.

  Accordingly, the present inventors have found that each of the “2. head size reduction”, “3. high NA”, and “4. We focused on performance and benchmarked.

  Benchmark results are shown in FIGS. 1A and 1B. FIG. 1A is a graph showing the relationship between NA and FOV for an existing laser scanning endoscope apparatus. FIG. 1B is a graph showing the relationship between the head size, NA, and FOV for an existing laser scanning endoscope. In addition, the point indicated by the legend “Rotation” in the graph is that the scanning of the laser beam to the living tissue is performed by rotating the optical element in the head portion of the endoscope as shown in Non-Patent Documents 3 and 4 above. It is the performance of the laser scanning microscope which performs.

  First, FIG. 1A plots the performance of an existing laser scanning endoscope apparatus having the above-described configurations, with NA on the horizontal axis and FOV on the vertical axis. Referring to FIG. 1A, it is shown that NA and FOV are in an opposite relationship (inversely proportional relationship) as an overall trend, and as discussed above, “3. High NA” and “4. It can be seen that it is difficult to achieve both “field of view”.

  Next, in FIG. 1B, the horizontal axis represents the diameter of the head portion, and the vertical axis represents FOV × NA, which is the figure of merit of the endoscope apparatus. Is a plot of its performance. Referring to FIG. 1B, it can be seen that if the diameter of the head portion is set to several mm or less, the maximum value of FOV × NA is about 0.3 (mm) even if it is the highest.

  Referring to FIG. 1B, among the existing laser scanning endoscope apparatuses that have been benchmarked this time, the laser scanning endoscope apparatus having the highest FOV × NA value is an actuator-type laser scanning endoscope apparatus. It turns out that it is an endoscope apparatus. However, since the actuator-type laser scanning endoscope apparatus is configured to move the entire optical system, if an attempt is made to obtain a wider field of view, that is, an attempt to move the optical system so as to scan a wider area. The scanning speed is considered to be limited. Thus, in the actuator-type laser scanning endoscope apparatus, although not shown in FIG. 1B, it is difficult to achieve both “4. wide field of view” and “5. high-speed scanning”.

  In the above, the content which the present inventors examined about the laser scanning type endoscope apparatus by other existing structures was demonstrated. From the above examination results, the present inventors, in the configuration of the existing laser scanning endoscope apparatus, “1. Depth of penetration”, “2. Miniaturization of the head”, “3. High NA”, It was found that it was difficult to simultaneously satisfy “4. Wide field of view” and “5. High-speed scanning”. Among them, in particular, it is difficult to satisfy “2. Miniaturization of the head”, “3. High NA” and “4. Wide field of view” at the same time with the configuration of the existing laser scanning endoscope apparatus. it was thought. As a result of examining configurations satisfying “2. Miniaturization of head portion”, “3. High NA”, and “4. Wide field of view” among the above performances, the present inventors disclosed the following disclosure. Such a laser scanning endoscope apparatus has been conceived. Hereinafter, a preferred embodiment of the laser scanning endoscope apparatus according to the present disclosure will be described.

(2. First Embodiment)
First, a configuration example of the laser scanning endoscope apparatus according to the first embodiment of the present disclosure will be described with reference to FIGS. 2 and 3. FIG. 2 is a schematic diagram illustrating a configuration example of the laser scanning endoscope apparatus according to the first embodiment of the present disclosure. FIG. 3 is a schematic diagram schematically showing the configuration of the scanning unit shown in FIG. In addition, in the following drawings including FIG. 2 and FIG. 3, illustration of the supporting members that support the respective constituent members constituting the laser scanning endoscope apparatus according to the present disclosure is omitted, and detailed description is also omitted. However, each component member is appropriately supported by various support members so as not to hinder the propagation of laser light and the drive of each component member described below.

  Referring to FIG. 2, the laser scanning endoscope apparatus 1 according to the first embodiment includes a laser light source 110, a beam splitter 120, an optical fiber 140, optical fiber light guiding lenses 130 and 150, an endoscope 160, A photodetector 170, a control unit 180, an output unit 190, and an input unit 195 are provided. In FIG. 2, for the sake of simplicity, only the configuration related to the acquisition of image data by laser scanning is illustrated among the functions of the laser scanning endoscope apparatus 1. However, the laser scanning endoscope apparatus 1 may further include various configurations included in other known endoscope apparatuses in addition to the configuration illustrated in FIG.

  In the laser scanning endoscope apparatus 1 according to the first embodiment, laser light emitted from the laser light source 110 is converted into a beam splitter 120, an optical fiber light guide lens 130, an optical fiber 140, and an optical fiber light guide lens. The light passes through 150 in order and is guided into the endoscope 160. A partial region of the endoscope 160 is inserted into a body cavity of a human or an animal to be observed (hereinafter referred to as a patient as an example), and laser light guided into the endoscope 160 is Irradiation is performed on the living tissue 500 in the body cavity of the patient to be observed. When the biological tissue 500 to be observed is irradiated with laser light, the biological tissue 500 receives various physical information or chemical information such as reflected light, scattered light, fluorescence, and various kinds of light generated by the nonlinear optical effect. Inclusion light is emitted. The return light from the living tissue 500 including various physical information or chemical information follows the above optical path in reverse, that is, the optical fiber light guide lens 150, the optical fiber 140, and the optical fiber. The light passes through the light guide lens 130 and is guided to the beam splitter 120. The beam splitter 120 guides the return light from the living tissue 500 to the photodetector 170. Various information regarding the living tissue 500 is acquired as image data by appropriately performing image signal processing on the image signal corresponding to the return light detected by the light detector 170 by the control unit 180. Hereinafter, each component of the laser scanning endoscope apparatus 1 will be described in detail. In the following description, laser light is emitted from the laser light source 110, guided through the endoscope 160, and irradiated to the living tissue 500. The tissue 500 side is also referred to as a downstream side. Further, in order to describe the positional relationship between the constituent members arranged on the optical path of the laser beam, the upstream side in the optical path is also referred to as the front stage and the downstream side is also referred to as the rear stage.

  The laser light source 110 emits a laser beam that irradiates the biological tissue 500 that is an observation target. In the present embodiment, the configuration of the laser light source 110 is not limited to a unique one, and may be set as appropriate according to the observation target and the application of the laser scanning endoscope apparatus 1. For example, the laser light source 110 may be a solid laser or a semiconductor laser. Moreover, the medium (material) of the solid-state laser and the semiconductor laser may be appropriately selected so as to emit laser light in a desired wavelength band according to the application of the laser scanning endoscope apparatus 1. For example, the material of the laser light source 110 is appropriately selected so as to emit light in a near-infrared wavelength band that is known to have relatively high permeability to the living body tissue 500 of the human body.

  Further, for example, the laser light source 110 may emit a continuous wave laser (CW laser) or a pulsed laser (pulse laser). When the laser light source 110 emits a CW laser, for example, in the laser scanning endoscope apparatus 1, various observations using one-photon confocal reflection or confocal fluorescence may be performed. When the laser light source 110 emits a pulse laser, for example, the laser scanning endoscope apparatus 1 may perform various observations using multiphoton excitation, nonlinear optical phenomena, or the like.

  The beam splitter 120 guides light incident from one direction and light incident from the other direction in different directions. Specifically, the beam splitter 120 guides the laser light emitted from the laser light source 110 to the optical fiber 140 via the optical fiber light guide lens 130. Further, the beam splitter 120 guides the return light by the laser light irradiated to the living tissue 500 to be observed to the photodetector 170. That is, the beam splitter 120 guides the laser light incident from the upstream side to the optical fiber 140 via the optical fiber light guiding lens 130 and the biological body incident from the downstream side, as indicated by a dotted arrow in FIG. Return light from the tissue 500 is guided to the photodetector 170.

  The optical fiber light guiding lenses 130 and 150 are respectively provided at the front and rear end portions of the optical fiber 140, and make the light incident on the optical fiber 140 and guide the light emitted from the optical fiber 140 to the subsequent member. Shine. Specifically, the optical fiber light guide lens 130 causes the light emitted from the laser light source 110 and guided by the beam splitter 120 to enter the optical fiber 140. The optical fiber light guide lens 130 guides the return light from the living tissue 500 that has passed through the optical fiber 140 to the beam splitter 120.

  The optical fiber 140 is a light guide member that guides the laser light emitted from the laser light source 110 to the inside of the endoscope 160. The optical fiber 140 is extended inside the endoscope 160 and guides the laser light to a head portion corresponding to the distal end portion of the endoscope 160. The laser light guided to the head portion of the endoscope 160 by the optical fiber 140 is guided to the scanning portion 163 provided in the head portion of the endoscope 160 described later via the optical fiber light guide lens 150. The The living tissue 500 is irradiated with laser light by the scanning unit 163, and the generated return light is incident on the optical fiber 140 by the optical fiber light guide lens 150. The return light is guided to the outside of the endoscope 160 by the optical fiber 140.

  As described above, the optical fiber light guiding lens 150 is provided in the head portion of the endoscope 160 and guides the laser light guided through the optical fiber 140 to the scanning unit 163. Further, the optical fiber light guide lens 150 makes the return light of the laser light irradiated to the living tissue 500 by the scanning unit 163 enter the optical fiber 140 and guide it to the outside of the endoscope 160. The optical fiber light guide lens 150 can function as a collimator lens that guides the laser light guided through the optical fiber 140 to the scanning unit 163 as substantially parallel light. By adjusting the position of the optical fiber light guide lens 150 in the optical axis direction (longitudinal direction of the lens barrel 161), the convergence of the laser light in an objective lens 165 that focuses laser light on the living tissue 500, which will be described later, is performed. Since the state and the divergence state change, the observation depth can be changed. Thus, the optical fiber light guide lens 150 can serve as an observation depth adjustment mechanism for adjusting the observation depth.

  Here, in the present embodiment, the configuration of the optical fiber 140 is not limited to a unique one, and may be set as appropriate according to the object to be observed and the application of the laser scanning endoscope apparatus 1. For example, when the laser scanning endoscope apparatus 1 performs observation using confocal reflection, a single mode optical fiber may be used as the optical fiber 140. Further, when the optical fiber 140 is a single mode optical fiber, for example, a plurality of single mode optical fibers may be bundled and used as a bundle.

  Further, for example, when the laser scanning endoscope apparatus 1 performs observation using multiphoton excitation, the return light mode is not limited, so that the optical fiber 140 may be a multi-core optical fiber or a double-clad optical fiber. May be used. Further, when the optical fiber 140 is a double clad optical fiber, for example, the core guides laser light (that is, excitation light) to the head portion of the endoscope 160 and returns light from the living tissue 500 (that is, , Fluorescent light) may be guided to the outside of the endoscope 160 by the inner cladding. Thus, by using a double clad optical fiber as the optical fiber 140, more efficient light guide of the laser light and the return light is possible. A specific configuration of the laser scanning observation apparatus according to the present embodiment in the case of performing observation using two-photon excitation will be described in detail in the following (6-2. Laser scanning probe).

  Further, for example, a plurality of optical fibers 140 may be provided, and an optical fiber that guides laser light to the head portion of the endoscope 160 and return light from the living tissue 500 are guided to the outside of the endoscope 160. The optical fiber that emits light may be constituted by different optical fibers.

  When the laser light source 110 emits a pulse laser, in order to suppress the nonlinear optical effect generated in the optical fiber 140, the optical fiber 140 has a core portion with a large mode area or a hollow core type. It is desirable to be a photonic crystal optical fiber. Similarly, when the laser light source 110 emits a pulse laser, in consideration of the dispersion generated in the optical fiber 140 and the broadening of the pulse width (pulse time width) associated with the dispersion, various kinds of elements are provided in the front stage of the optical fiber 140. A dispersion compensation element may be provided.

  Here, in the present embodiment, the optical fiber 140 may not necessarily be used depending on the configuration of the apparatus. For example, in the laser scanning probe or the laser scanning endoscope apparatus 1 according to this embodiment, it is necessary to guide the laser light from the light source to the probe or endoscope 160 that irradiates the observation target with the laser light. Therefore, the optical fiber 140 can be preferably used. However, in the laser scanning microscope apparatus, for example, a sample to be observed can be placed on a stage provided in the apparatus and the sample can be irradiated with laser light. Therefore, in the laser scanning microscope apparatus according to the present embodiment, an optical system that guides laser light from the light source to the sample can be appropriately arranged in the housing of the apparatus, and thus the optical fiber 140 is not necessarily used. May be.

  The endoscope 160 has a tubular shape, and a partial region including a head portion which is a distal end portion thereof is inserted into a body cavity of a patient. By scanning the biological tissue 500 in the body cavity with the laser beam by the head unit, various information regarding the biological tissue 500 is acquired. Details of the laser scanning function of the head portion of the endoscope 160 will be described later with reference to FIG.

  Here, in addition to the laser scanning function, the head portion of the endoscope 160 may be further provided with various configurations of other known endoscopes. For example, the head portion of the endoscope 160 includes an imaging unit that images the inside of the body cavity of the patient, a treatment tool for performing various treatments on the affected part, and water or air for cleaning the lens of the imaging unit. A cleaning nozzle or the like may be provided. The endoscope 160 can search for a site to be observed while monitoring the state in the body cavity of the patient by the imaging unit, and can perform laser scanning on the site to be observed. However, since the configurations of the imaging unit, the treatment tool, the washing nozzle, and the like are the same as the configurations of other known endoscopes, in the following description, the head unit is included in the functions of the endoscope 160. The laser scanning function will be mainly described, and detailed description of other functions and configurations will be omitted.

  The photodetector 170 detects return light from the living tissue 500 guided to the outside of the endoscope 160 by the optical fiber 140. Specifically, the photodetector 170 detects the return light from the living tissue 500 as an image signal having a signal intensity corresponding to the light intensity. For example, the photodetector 170 may include a light receiving element such as a photodiode or a photomultiplier tube (PMT). Further, for example, the photodetector 170 may include various imaging elements such as a charge coupled device (CCD) and a complementary metal oxide semiconductor (CMOS). In addition, a spectroscopic element may be provided in front of the light detector 170 for the purpose of acquiring spectral information of the return light. The light detector 170 converts the return light generated by the scanning of the living tissue 500 with the laser light continuously (when the laser light is a CW laser) or intermittently (the laser light is a pulse laser) in the scanning order of the laser light. Can be detected). The photodetector 170 transmits an image signal corresponding to the detected return light to the control unit 180.

  The control unit 180 controls the laser scanning endoscope apparatus 1 in an integrated manner, and performs laser scanning control on the living tissue 500 and various image signal processing on an image signal obtained as a result of the laser scanning.

  The function and configuration of the control unit 180 will be described in detail. Referring to FIG. 2, the control unit 180 includes an image signal acquisition unit 181, an image signal processing unit 182, a drive control unit 183, and a display control unit 184. Note that the functions of each component in the control unit 180 may be all performed by various signal processing circuits such as a CPU (Central Processing Unit) and a DSP (Digital Signal Processor).

  The image signal acquisition unit 181 acquires an image signal transmitted from the photodetector 170. Here, in the photodetector 170, the return light is detected continuously or intermittently in the scanning order of the laser light, so that the image signal corresponding to the return light is similarly received in the image signal acquisition unit 181. It is transmitted continuously or intermittently in the scanning order of the laser light. The image signal acquisition unit 181 can acquire the image signals received in such a laser beam scanning order continuously or intermittently in time series. When the image signal transmitted from the photodetector 170 is an analog signal, the image signal acquisition unit 181 may convert the received image signal into a digital signal. That is, the image signal acquisition unit 181 may have an analog / digital conversion function (A / D conversion function). The image signal acquisition unit 181 transmits the digitized image signal to the image signal processing unit 182.

  The image signal processing unit 182 generates image data by performing various types of signal processing on the received image signal. In the present embodiment, the image signal corresponding to the laser light scanned on the living tissue 500 is detected by the photodetector 170 continuously or intermittently in the scanned order, and the image signal is acquired via the image signal acquisition unit 181. It is transmitted to the signal processing unit 182. The image signal processing unit 182 generates image data corresponding to the scanning of the laser light to the living tissue 500 based on the image signal transmitted continuously or intermittently. Further, the image signal processing unit 182 generates image data by performing signal processing corresponding to the application depending on the application of the laser scanning endoscope apparatus 1, that is, depending on what image data is desired to be acquired. May be. The image signal processing unit 182 can generate image data by performing processing similar to various image data generation processing performed by a general laser scanning endoscope apparatus. Further, the image signal processing unit 182 generates various kinds of image signal processing such as noise removal processing, black level correction processing, brightness (brightness) and white balance adjustment processing, and the like. The signal processing may be performed. The image signal processing unit 182 transmits the generated image data to the drive control unit 183 and the display control unit 184.

  The drive control unit 183 performs laser scanning on the living tissue 500 by controlling the driving of the laser scanning function in the head unit of the endoscope 160. Specifically, the drive control unit 183 drives the scanning unit 163 by controlling the driving of the rotation mechanism 167 and / or the parallel movement mechanism 168 provided in the head unit of the endoscope 160 to be described later, so that the living tissue Laser scanning to 500 is performed. Here, the drive control unit 183 can adjust the laser scanning conditions such as the scanning speed in laser scanning and the interval of laser irradiation by controlling the driving of the rotation mechanism 167 and / or the parallel movement mechanism 168. The drive control unit 183 may adjust the laser scanning condition based on a command input from the input unit 195 or based on image data generated by the image signal processing unit 182. Good. The drive control of the rotation mechanism 167 and / or the translation mechanism 168 by the drive control unit 183 will be described in detail when the function and configuration of the endoscope 160 is described.

  The display control unit 184 controls the driving of the data display function in the output unit 190 and displays various data on the display screen of the output unit 190. In the present embodiment, the display control unit 184 controls the driving of the output unit 190 and displays the image data generated by the image signal processing unit 182 on the display screen of the output unit 190.

  The output unit 190 is an output interface for outputting various types of information processed in the laser scanning endoscope apparatus 1 to an operator (user). The output unit 190 is configured by a display device that displays text data, image data, or the like on a display screen, such as a display device or a monitor device. In the present embodiment, the output unit 190 displays the image data generated by the image signal processing unit 182 on the display screen. Note that the output unit 190 includes various output devices having a data output function, such as a sound output device such as a speaker or a headphone that outputs sound data as sound, and a printer device that prints and outputs various data on paper. Furthermore, you may have.

  The input unit 195 is an input interface for allowing a user to input various information, instructions regarding processing operations, and the like to the laser scanning endoscope apparatus 1. The input unit 195 is configured by an input device having operation means operated by a user, such as a mouse, a keyboard, a touch panel, a button, a switch, and a lever. In the present embodiment, the user can input various commands related to the operation of the endoscope 160 from the input unit 195. Specifically, the laser scanning conditions in the endoscope 160 may be controlled in accordance with a command input from the input unit 195. In addition, various configurations other than the laser scanning function of the endoscope 160, for example, driving of the imaging unit, the treatment tool, the cleaning nozzle, and the like may be controlled in accordance with a command input from the input unit 195.

  The schematic configuration of the laser scanning endoscope apparatus 1 according to the first embodiment of the present disclosure has been described above with reference to FIG. Next, the function and configuration of the endoscope 160 will be described in more detail with reference to FIG. 3 in conjunction with FIG. FIG. 3 is a schematic diagram schematically showing the configuration of the scanning unit 163 shown in FIG. In FIG. 3, for the sake of simplicity, the configuration related to the laser scanning function among the functions of the endoscope 160 is mainly illustrated.

  2 and 3, the endoscope 160 according to the first embodiment includes a lens barrel (housing) 161, a window unit 162, a scanning unit 163, a rotation mechanism 167, and a parallel movement mechanism 168.

  In the present embodiment, as shown in FIG. 2, a partial region of the endoscope 160 is brought into contact with a living tissue 500 that is an observation target, and laser light is irradiated from the scanning unit 163 to the contact region. Then, the scanning unit 163 is rotated with the insertion direction of the endoscope 160 (longitudinal direction of the lens barrel 161) as the rotation axis direction in a state where the living tissue 500 is irradiated with the laser light from the scanning unit 163, and / or scanning. The living tissue 500 is scanned with laser light by translating the part 163 in the insertion direction of the endoscope 160. In the following description, “contact” of the endoscope 160 or its constituent members to the living tissue 500 may represent “contact or proximity”.

  Here, in the following description, as shown in FIGS. 2 and 3, the direction in which laser scanning is performed by the rotation of the scanning unit 163 (the direction perpendicular to the paper surface) is the x axis, and the endoscope 160 (lens barrel 161) is inserted. In the description, the direction is defined as the y-axis, and the direction perpendicular to the x-axis and the y-axis is defined as the z-axis. Here, in FIG. 2, a cross-sectional view of the configuration of the scanning unit 163 of the endoscope 160 and the vicinity thereof is schematically shown when cut along a cross section passing through the central axis of the lens barrel 161 and parallel to the yz plane. Show. FIG. 3 is a diagram illustrating a cross section taken along the line AA in FIG. 2 as viewed from the positive direction of the y-axis. However, FIG. 3 illustrates a state in which the scanning unit 163 is rotated by a predetermined angle about the rotation axis.

  The lens barrel 161 is a tubular casing, and a head portion which is a tip portion thereof is provided with various configurations relating to a laser scanning function such as a window portion 162, a scanning portion 163, a rotating mechanism 167, and a parallel moving mechanism 168. It is done. Note that the diameter of the head portion of the lens barrel 161 is, for example, about several mm or less. In this embodiment, as shown in FIGS. 2 and 3, the lens barrel 161 has a cylindrical shape, but the cross-sectional shape of the lens barrel 161 is not limited to this example, and any tubular casing can be used. It may be a shape. For example, the cross-sectional shape of the lens barrel 161 may be an arbitrary polygon. However, considering the reduction of the physical burden on the patient, the cross-sectional shape of the lens barrel 161 is preferably a nearly circular shape. Therefore, when the cross-sectional shape of the lens barrel 161 is an arbitrary polygon, The polygon preferably has a shape that is as close to a circle as possible with as many vertices as possible. In the following description, the longitudinal direction of the endoscope 160 and the lens barrel 161 is also referred to as the long axis direction of the housing.

  In addition, the head unit may be provided with various mechanisms other than the laser scanning function such as an imaging unit, a treatment tool, and a cleaning nozzle. These various mechanisms are electrically and mechanically connected to the apparatus main body of the laser scanning endoscope apparatus 1 by a cable, a wire (both not shown) or the like extending inside the lens barrel 161. It is connected and driven by control from the apparatus main body. For example, these various mechanisms may be controlled according to a command input from the input unit 195 by the user.

  The window part 162 is provided in a partial region of the lens barrel 161 and contacts the living tissue 500 in the body cavity of the patient to be observed. In the present embodiment, the window portion 162 is provided in a partial region of the side wall substantially parallel to the longitudinal direction of the lens barrel 161 and has a cylindrical surface in accordance with the shape of the side wall of the lens barrel 161. As shown in FIG. 2, the laser light guided through the lens barrel 161 by the optical fiber 140 is irradiated to the living tissue 500 through the window portion 162. Further, the return light from the living tissue 500 enters the inside of the lens barrel 161 through the window portion 162 and is guided to the outside of the endoscope 160 by the optical fiber 140. Therefore, it is desirable that the material of the window portion 162 is transparent (having high transmittance) with respect to the wavelength band of the laser light emitted from the laser light source 110 and the wavelength band of the return light from the living tissue 500. Specifically, the window part 162 may be comprised with various well-known materials, such as quartz, glass, a plastics, for example.

  In addition, as described above, in the present embodiment, laser light is emitted to the living tissue 500 by rotating around the y axis of the scanning unit 163 and / or translating the scanning unit 163 in the y axis direction. Scan. Therefore, it is desirable that the optical system after the scanning unit 163 (until the laser beam is applied to the living tissue 500) is stored with respect to the rotation and / or translation of the scanning unit 163. The shape of the window unit 162 may be set from the viewpoint that the optical system after the scanning unit 163 is preserved with respect to the rotation and / or parallel movement of the scanning unit 163.

  Furthermore, since the window portion 162 contacts the living tissue 500 during laser scanning, the window portion 162 is required to have a predetermined strength from the viewpoint of safety. In this way, the thickness and material of the window part 162 are designed to have sufficient strength so as not to pose a risk to the patient in consideration of the window part 162 coming into contact with the living tissue 500. For example, the window portion 162 preferably has a thickness of about several hundred μm although it depends on the material.

  In the example shown in FIGS. 2 and 3, the window portion 162 has a cylindrical surface conforming to the shape of the side wall of the lens barrel 161, but the present embodiment is not limited to this example. The shape of the window part 162 may be other shapes, for example, other various curved surfaces or planes. In the example shown in FIGS. 2 and 3, the window portion 162 is provided only in a partial region in the circumferential direction (outer circumferential direction) of the lens barrel 161, but the present embodiment is not limited to such an example. The window portion 162 may be provided with a width in the longitudinal direction of the lens barrel 161 in the entire circumferential region of the lens barrel 161. The length in which the window portion 162 is provided in the circumferential direction of the lens barrel 161 may be appropriately set according to the areas of the regions that contact each other when the lens barrel 161 is pressed against the living tissue 500 during laser scanning.

  The scanning unit 163 rotates and / or translates relative to the window unit 162 within the lens barrel 161 in a state in which the living tissue 500 is irradiated with laser light through the window unit 162, thereby moving the scanning unit 163 relative to the living tissue 500. Then, the laser beam is scanned.

  The function and configuration of the scanning unit 163 will be described in detail. The scanning unit 163 includes an optical path changing element 164, an objective lens 165, an aberration correction element 166, and a housing 169.

  The optical path changing element 164 guides the laser light guided in the longitudinal direction of the lens barrel 161 through the lens barrel 161 to the lens surface of the objective lens 165. Specifically, the optical path changing element 164 receives the laser light guided in the lens barrel 161 by the optical fiber 140, changes the optical path, and guides it on the optical axis of the objective lens 165. In the example shown in FIG. 2, the laser light guided through the optical fiber 140 is collimated into substantially parallel light by the optical fiber light guide lens 150, guided in the y-axis direction, and enters the optical path changing element 164. The optical path changing element 164 is, for example, a bending mirror, and reflects the laser light guided from the optical fiber light guiding lens 150 in the z-axis direction at a substantially right angle, and is located in the z-axis direction when viewed from the objective lens 165. Guide the light toward In the present embodiment, the optical path changing element 164 is not limited to the bending mirror, and may be other various optical elements. A modification of the present embodiment in which the optical path changing element 164 is another optical element will be described in detail below (4. Modification).

  The objective lens 165 is provided inside the lens barrel 161 and condenses the laser light on the living tissue 500 through the window portion 162. Specifically, the objective lens 165 collects the laser light guided from the optical path changing element 164 and irradiates the living tissue 500 through the window unit 162. Further, the return light from the living tissue 500 is incident on the inside of the lens barrel 161 via the window portion 162 and the objective lens 165 and guided to the outside of the endoscope 160 by the optical fiber 140. Therefore, it is desirable that the material of the objective lens 165 is transparent (having high transmittance) with respect to the wavelength band of the laser light emitted from the laser light source 110 and the wavelength band of the return light from the living tissue 500. Specifically, the objective lens 165 may be made of various known materials such as quartz, glass, and plastic. For example, the objective lens 165 may be an aspheric lens. In the present embodiment, it is desirable that the objective lens 165 has a relatively high NA in order to acquire high-resolution image data. For example, the NA of the objective lens 165 may be 0.5 or more.

  In the example shown in FIGS. 2 and 3, the objective lens 165 is provided in the rear stage of the optical path changing element 164 in the scanning unit 163 and is configured to rotate together with the optical path changing element 164. The position where is provided is not limited to such a position. For example, the objective lens 165 may not be included in the scanning unit 163 (that is, may not rotate with other components of the scanning unit 163), and may be provided in front of the optical path changing element 164. In the case of this configuration, the traveling direction of the laser light collected by the objective lens 165 is changed by the optical path changing element 164, passes through the window portion 162, and is scanned with respect to the living tissue 500. However, when the objective lens 165 is provided upstream of the optical path changing element 164, the objective lens 165 operates relatively in consideration of the distance from the objective lens 165 to the optical path changing element 164 and the distance from the optical path changing element 164 to the living tissue 500. It is preferable to use an objective lens 165 having a long distance.

  The aberration correction element 166 is provided in front of the window portion 162 and corrects an aberration that occurs when the laser light is focused on the living tissue 500. Specifically, the aberration correction element 166 includes at least each aberration such as chromatic aberration, spherical aberration, and astigmatism caused by the objective lens 165 and / or the window unit 162 when the living tissue 500 is irradiated with laser light. Correct either one. For example, as the aberration correction element 166 for correcting the spherical aberration, for example, a parallel plate is provided between the objective lens 165 and the window portion 162 in order to compensate for the spherical aberration due to the thickness error of the window portion 162 and the objective lens 165. May be used. However, when the objective lens 165 is an aspheric lens, the objective lens 165 itself may be provided with a spherical aberration correction function. For example, as the aberration correction element 166 for correcting astigmatism, various cylindrical lenses and cylindrical meniscus lenses can be used. The specific configuration of the aberration correction element 166 will be described in detail below (5. Configuration of the aberration correction element).

  Here, the degree of the aberration is influenced by the NA value of the objective lens 165 and the shape of the window portion 162. Specifically, the higher the NA of the objective lens 165, the greater the thickness of the component of the window portion 162, and the smaller the curvature of the window portion 162 (that is, the smaller the diameter of the lens barrel 161), the more the aberration becomes. The degree tends to increase. Therefore, what optical element is used as the aberration correction element 166 and its specific configuration may be appropriately selected according to the shapes and characteristics of the window portion 162 and the objective lens 165.

  As described above, when the observation depth is changed by, for example, the optical fiber light guide lens 150 functioning as a collimator lens, the non-designed lens is designed in consideration of the variation in aberration accompanying the change in the observation depth. An aberration correction element that corrects point aberration can be suitably applied. In addition, when the laser scanning endoscope apparatus 1 performs observation using two-photon excitation, an aberration correction element that corrects chromatic aberration can be suitably applied. The specific configuration of the aberration correction element in the case of having such an observation depth adjusting mechanism or performing observation using two-photon excitation will be described in detail in the following (6-2. Laser scanning probe). explain.

  2 and 3, the aberration correction element 166 is provided between the optical path changing element 164 and the objective lens 165, but the position where the aberration correction element 166 is provided is not limited to this position. . The aberration correction element 166 may be provided at any position as long as the laser light emitted from the optical fiber 140 passes through the window portion 162, and rotates and translates as a constituent member of the scanning portion 163. It may be configured not to.

  In addition, for the purpose of suppressing the aberration that occurs when the laser light is focused on the living tissue 500, the refractive index of the objective lens 165 and the refractive index of the window portion 162 are set in the space between the objective lens 165 and the window portion 162. And immersion with a liquid having substantially the same refractive index. The liquid may be, for example, oil that satisfies the above conditions. Here, it is generally known that the refractive index of the living tissue 500 is closer to glass or the like that can be selected as the material of the window portion 162 than air. Accordingly, by immersing the space between the objective lens 165 and the window portion 162 with a liquid having a predetermined refractive index, the optical path from the objective lens 165 to the living tissue 500 through the window portion 162 is increased. The change in refractive index, particularly the refractive index difference on the inner surface of the window portion 162 can be reduced, and the occurrence of aberration can be suppressed. When the space between the objective lens 165 and the window portion 162 is immersed, the configuration of the aberration correction element 166 is appropriately selected in consideration of optical characteristics such as the refractive index of the immersed liquid. For the purpose of suppressing the aberration, the medium filled in the space between the objective lens 165 and the window portion 162 is not limited to a liquid, and may be made of various known materials that satisfy the above refractive index conditions. It may be another medium configured.

  Further, the optical path changing element 164 may have an aberration correction function by making the reflection surface of the laser beam of the bending mirror, which is the optical path changing element 164, into an aspherical shape. When the optical path changing element 164 has an aberration correcting function, the configuration of the aberration correcting element 166 is appropriately selected in consideration of the performance of the aberration correcting function of the optical path changing element 164.

  The housing 169 accommodates each component of the scanning unit 163 in an internal space. In the present embodiment, as shown in FIGS. 2 and 3, the housing 169 has a substantially rectangular parallelepiped shape having a space inside, and the optical path changing element 164 and the aberration correction element 166 are disposed in the internal space. . An objective lens 165 is disposed in a partial region of one surface of the housing 169 facing the inner wall of the lens barrel 161. As shown in FIG. 2, the laser light incident on the scanning unit 163 enters an optical path changing element 164 provided in the housing 169, the optical path is changed, passes through the aberration correction element 166, and the objective lens The light is guided to the outside of the housing 169 through 165. It is assumed that the optical path changing element 164 and the aberration correcting element 166 are fixed to the housing 169 by a support member (not shown) or the like in the internal space of the housing 169.

  The rotation mechanism 167 rotates at least the objective lens 165 in the lens barrel 161 with a rotation axis that is orthogonal to the optical axis of the objective lens 165 and does not pass through the objective lens 165 so that the laser light scans the living tissue 500. Specifically, the rotation mechanism 167 may be configured by, for example, various motors that are driven by electromagnetic force, ultrasonic waves, or the like, motors that include piezoelectric elements, and the like. The rotation mechanism 167 may be configured by a small air turbine. Furthermore, the rotation mechanism 167 may be configured by a mechanism that transmits torque from the outside of the endoscope 160 using a coupling mechanism.

  In the example shown in FIGS. 2 and 3, the rotation mechanism 167 rotates the scanning unit 163, that is, the optical path changing element 164, the objective lens 165, the aberration correction element 166, and the housing 169 integrally with the y axis as the rotation axis. . That is, the rotation mechanism 167 rotates the scanning unit 163 about the y axis as the rotation axis so that the optical axis of the objective lens 165 scans the surface of the window unit 162 in the x axis direction. Thus, in the present embodiment, the laser beam is scanned for one line in the x-axis direction in the living tissue 500 while the rotation mechanism 167 rotates the scanning unit 163 once. Therefore, by detecting the return light of the laser light, it is possible to acquire, as image data, the characteristics of the part of the living tissue 500 corresponding to the line scanned with the laser light by the rotation of the rotation mechanism 167.

  The translation mechanism 168 translates at least the objective lens 165 in the direction of the rotation axis of the rotation mechanism 167 within the lens barrel 161. Specifically, the parallel movement mechanism 168 may be configured by, for example, a linear actuator, a piezoelectric element, or the like. 2 and 3, the translation mechanism 168 translates the scanning unit 163, that is, the optical path changing element 164, the objective lens 165, the aberration correction element 166, and the housing 169 integrally in the y-axis direction. . In other words, the translation mechanism 168 translates the scanning unit 163 in the y-axis direction so that the optical axis of the objective lens 165 scans the surface of the window unit 162 in the y-axis direction. Here, in the present embodiment, the laser light incident on the scanning unit 163 is collimated into substantially parallel light by the optical fiber light guide lens 150. Therefore, even if the scanning unit 163 is translated in the y-axis direction by the translation mechanism 168, the focal point (focus) of the laser light applied to the living tissue 500 does not change.

  As described above, in this embodiment, the rotation mechanism 167 rotates the scanning unit 163 to scan the laser beam in the x-axis direction, and the parallel movement mechanism 168 translates the scanning unit 163 in the y-axis direction. The laser beam is scanned. Accordingly, the laser beam is scanned two-dimensionally on the xy plane (a plane defined by the x axis and the y axis) in the living tissue 500. Therefore, by detecting the return light of the laser light, the characteristics of the portion of the living tissue 500 scanned with the laser light can be acquired as two-dimensional image data.

  In the present embodiment, the scan speed in the x-axis direction is controlled by the rotation speed of the scanning unit 163 by the rotation mechanism 167, and the scan speed in the y-axis direction is controlled by the parallel movement speed of the scanning unit 163 by the translation mechanism 168. Therefore, the rotation speed and the parallel movement speed may be set as appropriate based on the sampling frequency of the image data. Further, the range of image data to be acquired is controlled by the movable range (movable distance) of the scanning unit 163 by the parallel movement mechanism 168. Therefore, the movable distance may be appropriately set in consideration of the length of the window portion 162 in the y-axis direction.

  In the example shown in FIGS. 2 and 3, the rotation mechanism 167 and the parallel movement mechanism 168 rotate and rotate the scanning unit 163, that is, the optical path changing element 164, the objective lens 165, the aberration correction element 166, and the housing 169 integrally. Although translated, the present embodiment is not limited to this example. For example, the rotation mechanism 167 and the translation mechanism 168 may rotate and translate only the objective lens 165 and its holder so that the laser light scans the living tissue 500. When the rotation mechanism 167 and the translation mechanism 168 rotate and translate only the objective lens 165 and its holder, the optical path changing element 164 does not rotate and translate, and the objective lens 165 by the rotation mechanism 167 and the translation mechanism 168. The laser light may be guided to the lens surface of the objective lens 165 that rotates and translates by dynamically changing the optical path of the laser light in synchronization with the rotation and translation of the objective lens 165. In that case, for example, the aberration correction element 166 is provided between the optical path changing element 164 and the objective lens 165 without being rotated and translated, and is synchronized with the dynamic change of the optical path by the optical path changing element 164. The aberration correction function may be dynamically changed. Further, for example, the objective lens 165 and the aberration correction element 166 may be provided in front of the optical path changing element 164, and the rotating mechanism 167 and the parallel moving mechanism 168 may rotate and translate only the optical path changing element 164. As described above, in this embodiment, the laser light may be scanned with respect to the living tissue 500 by the rotation and / or translation of the scanning unit 163. Whether to perform light scanning may be appropriately set.

  Although not shown in FIGS. 2 and 3, the endoscope 160 is further provided with an optical axis direction moving mechanism that moves the scanning unit 163 in the z-axis direction, that is, in the optical axis direction of the objective lens 165. Also good. Specifically, the optical axis direction moving mechanism is configured by a small actuator, for example. By moving the scanning unit 163 in the z-axis direction by the optical axis direction moving mechanism, the depth of focus (that is, the observation depth) of the objective lens 165 with respect to the living tissue 500 can be changed. Note that the optical axis direction moving mechanism may also move only the objective lens 165 and its holder in the z-axis direction, like the rotating mechanism 167 and the parallel moving mechanism 168. Further, instead of moving the objective lens 165 in the optical axis direction, the focal length of the objective lens 165 may be changed by configuring the objective lens 165 with a variable focus lens. The endoscope 160 includes a focus servo mechanism that automatically adjusts the focal length by the optical axis direction moving mechanism and the variable focus lens by detecting the relative distance between the window portion 162 and the living tissue 500. You may have. The focal length adjustment mechanism using the optical axis direction moving mechanism and the variable focus lens is an example of the observation depth adjustment mechanism according to the present embodiment, similar to the optical fiber light guide lens 150 functioning as the collimator lens described above. is there.

  In the present embodiment, by using these observation depth adjustment mechanisms, it is possible to scan the living tissue 500 with laser light in the z-axis direction. Therefore, by combining the driving of the scanning unit 163 by the rotation mechanism 167 and the parallel movement mechanism 168 and the driving of the observation depth adjustment mechanism, the living tissue 500 can be scanned three-dimensionally with the laser beam, By detecting the return light, the characteristics of the living tissue 500 can be acquired as three-dimensional image data. Therefore, for example, a more convenient observation for the user is realized, such as searching for a site (for example, an affected part) to be observed while taking a plurality of layers of images in the depth direction.

  The schematic configuration of the laser scanning endoscope apparatus 1 according to the first embodiment of the present disclosure has been described above with reference to FIGS. 2 and 3. As described above, according to the laser scanning endoscope apparatus 1 according to the first embodiment, the objective lens 165 rotates around the y axis as the rotation axis in the lens barrel 161, thereby allowing the objective lens 165 to rotate via the window portion 162. Thus, the laser beam is scanned with respect to the living tissue 500 in the x-axis direction. Thus, the field of view (FOV) in the laser scanning endoscope apparatus 1 is not limited by the off-axis characteristics of the objective lens 165 by scanning the laser beam by the rotation of the objective lens 165. Accordingly, in the laser scanning endoscope apparatus 1, the range facing the window portion 162 while the objective lens 165 is rotating (that is, the range in which the laser beam is scanned in the x-axis direction) is secured as the FOV. A wide field of view is realized even when the NA of the lens 165 is relatively high. Moreover, since the window part 162 provided in the endoscope 160 of the laser scanning endoscope apparatus 1 according to the first embodiment is formed with a predetermined thickness, the window part 162 is formed on a living tissue. Safety when contacting is ensured. Furthermore, according to the laser scanning endoscope apparatus 1 according to the first embodiment, the aberration correction element 166 that corrects the aberration generated when the laser light is focused on the living tissue before the window unit 162. Is provided. Here, the aberration correction performance of the aberration correction element 166 is appropriately set according to the characteristics and shape of the objective lens 165 and the window portion 162 so as to correct aberrations caused by the objective lens 165 and / or the window portion 162. May be. Therefore, in the laser scanning endoscope apparatus 1, while using an objective lens having a relatively high NA, safety is ensured by providing a predetermined thickness in the window portion, and the influence of aberration is suppressed. It becomes possible to simultaneously obtain a high-quality image.

  Further, in the laser scanning endoscope apparatus 1 according to the first embodiment, the objective lens 165 is brought close to the living tissue 500 in order to scan the laser light by bringing the window portion 162 into contact with the living tissue 500. Therefore, even when the objective lens 165 having a relatively high NA is used, image data that can be observed up to a deeper part of the living tissue 500 can be acquired more stably at a higher resolution. .

  Here, an approximate value of FOV × NA in the laser scanning endoscope apparatus 1 according to the first embodiment will be calculated. As described above, the FOV of the laser scanning endoscope apparatus 1 is a range in which the laser light is scanned in the x-axis direction in the living tissue 500 by the rotation of the scanning unit 163. It can be considered that the length is in contact with the living tissue 500. Therefore, FOV is calculated by the following formula (1).

FOV = π × (outer diameter of window portion 162) × (contact angle with living tissue 500/360 °)
... (1)

  In addition, the “contact angle” in the mathematical formula (1) is cut along the xz plane of the lens barrel 161 corresponding to the length in the circumferential direction of the window portion 162 that is in contact with the living tissue 500. It is the central angle in the circle of the cross section (that is, the cross section of the lens barrel 161 shown in FIG. 3).

  Here, for example, it is assumed that the outer diameter of the window portion 162 is equal to the diameter of the lens barrel 161 and is 5 (mm). For example, it is assumed that the contact angle with the living tissue 500 is 60 °. By substituting these values into Equation (1), the FOV of the laser scanning endoscope apparatus 1 is calculated as FOV≈2.6 (mm). Therefore, for example, if the objective lens 165 with NA of 0.5 is used, the index FOV × NA indicating the performance of the laser scanning endoscope apparatus 1 is FOV × NA = 2.6 × 0.5 = 1. 3 As described in the above (1. Examination of laser scanning endoscope apparatus with other configuration), the FOV × NA value of the existing laser scanning endoscope is 0.3 (mm) even if it is the highest. The value of FOV × NA in a laser scanning microscope is also about 1.0 (mm). Therefore, the laser scanning endoscope apparatus 1 according to the first embodiment relates to the performances of “3. high NA” and “4. wide field of view”, the existing laser scanning endoscope and the existing laser scanning type. It can be said that it has higher performance than a microscope. As described above, in the laser scanning endoscope apparatus 1, by rotating the objective lens 165, “2. Head size reduction”, “3. High NA” and “4. Wide field of view” are realized simultaneously. Is done. That is, in the laser scanning endoscope apparatus 1, a high resolution and a wide field of view can be ensured. Therefore, by controlling the line interval and the sampling rate of laser scanning, it is possible to look over the living tissue over a wide range, or to enlarge the desired part as necessary and observe it with higher resolution. Observation of living tissue is realized.

  Further, by providing the laser scanning endoscope apparatus 1 with a mechanism for controlling the focal depth of the objective lens 165 to the living tissue 500, such as the optical axis direction moving mechanism described above, “1. Depth of penetration”. The predetermined performance can also be achieved.

  Further, consider “5. High-speed scanning performance” in the laser scanning endoscope apparatus 1. The scanning speed of the laser light in the laser scanning endoscope apparatus 1 is determined by the rotational speed of the scanning unit 163 by the rotation mechanism 167. Here, the rotation speed required for the scanning unit 163 will be roughly estimated. For example, assuming that one frame of image data is (x × y) = (500 (pixel) × 500 (pixel)), in order to realize a scanning speed of 1 fps, 500 lines are scanned with laser light per second. There is a need to. Therefore, the rotation speed required for the scanning unit 163 to realize the scan speed of 1 fps is 500 × 60 × 1 = 30000 (rpm). This is a rotation speed sufficiently realizable if the rotation mechanism 167 is constituted by various motors. In the laser scanning endoscope apparatus 1, it can be said that a scan speed of at least about 1 fps can be realized. .

  Although the case where the objective lens 165 is an aspherical lens has been described above, the present embodiment is not limited to such an example. For example, the objective lens 165 may be another optical element having an optical function equivalent to that of the aspherical lens, such as a green lens, a diffractive optical element, a hologram, and a phase modulator.

  Further, from the viewpoint of improving the scanning speed, it is preferable to use a material having a lighter specific gravity as the material of the objective lens 165 in order to realize high-speed rotation by the rotation mechanism 167.

  Further, instead of the objective lens 165, various optical elements such as a reflective objective lens, a free-form surface mirror, and a prism capable of condensing laser light and changing the optical path may be used. When an optical element capable of condensing laser light and changing the optical path is used instead of the objective lens 165, the optical path changing element 164 is not necessarily provided.

  In addition, a laser scanning mechanism that can be generally used may be provided between the laser light source 110 and the objective lens 165, which is configured by an optical polarization device such as a galvano mirror and a relay lens optical system.

  In the above description, the case where the parallel movement mechanism 168 is provided as a means for scanning the living tissue 500 in the y-axis direction has been described. However, the present embodiment is not limited to such an example. For example, the parallel movement mechanism 168 may not be provided, and image data for one line in the x-axis direction may be acquired by the rotation of the scanning unit 163 by the rotation mechanism 167. When the living tissue 500 is irradiated with the laser light, the laser light is irradiated to the living tissue 500 with a predetermined spread, so even if only one line of scanning in the x-axis direction is scanned, the y-axis direction. Image data having a predetermined width is acquired. Alternatively, when the translation mechanism 168 is not provided, the scanning of the laser light in the y-axis direction may be realized by the insertion operation of the endoscope 160 itself into the body cavity or the extraction operation from the body cavity. . In the case of a hand-held laser scanning probe such as the laser scanning probe 5 described below (6-2. Laser scanning probe), the laser scanning probe itself is used for the human or animal to be observed. Laser scanning in the y-axis direction may be performed by moving the body surface in the y-axis direction. Further, in the case where a stage 880 on which an observation target is placed is provided as in a laser scanning microscope apparatus 6 described below (6-3. Laser scanning microscope), the stage 880 is moved in the y-axis direction. The laser scanning in the y-axis direction may be performed by moving to the position. As described above, even when the translation mechanism 168 is not provided, observation is performed while moving the casing (more specifically, the window unit that irradiates the observation target with laser light) or the observation target in the y-axis direction. By irradiating the target with laser light, laser scanning in the y-axis direction can be performed.

(3. Second embodiment)
Next, with reference to FIG. 4A, a configuration example of the laser scanning endoscope apparatus according to the second embodiment of the present disclosure will be described. FIG. 4A is a schematic diagram illustrating a configuration example of a laser scanning endoscope apparatus according to the second embodiment of the present disclosure.

  Referring to FIG. 4A, a laser scanning endoscope apparatus 2 according to the second embodiment includes a laser light source 110, a beam splitter 120, an optical modulator 230, an optical fiber bundle 240, and optical fiber light guide lenses 130 and 150. , Endoscope 160, photodetector 170, control unit 280, output unit 190, and input unit 195. In FIG. 4A, for the sake of simplicity, only the configuration relating to the acquisition of image data by laser scanning is illustrated among the functions of the laser scanning endoscope apparatus 2. However, the laser scanning endoscope apparatus 2 may further include various configurations included in other known endoscope apparatuses in addition to the configuration illustrated in FIG. 4A.

  Here, in the laser scanning endoscope apparatus 2 according to the second embodiment of the present disclosure, an optical modulator 230 is newly provided with respect to the laser scanning endoscope apparatus 1 according to the first embodiment. The optical fiber bundle 240 and the control unit 280 are provided instead of the optical fiber 140 and the control unit 180, and the laser scanning endoscope apparatus 1 according to the first embodiment is provided for other configurations. It has the same configuration as. Therefore, in the description of the configuration of the laser scanning endoscope apparatus 2 according to the second embodiment below, the configuration that is different from the laser scanning endoscope apparatus 1 according to the first embodiment will be mainly described. Detailed description of the overlapping configuration will be omitted.

  Referring to FIG. 4A, the laser scanning endoscope apparatus 2 according to the second embodiment of the present disclosure has a beam compared to the laser scanning endoscope apparatus 1 according to the first embodiment illustrated in FIG. 2. An optical modulator 230 is provided between the splitter 120 and the optical fiber light guide lens 130. The laser scanning endoscope apparatus 2 includes an optical fiber bundle 240 instead of the optical fiber 140 of the laser scanning endoscope apparatus 1.

  The optical modulator 230 excites the laser light input via the laser light source 110 and the beam splitter 120 in a state where the intensity is modulated and multiplexed at different frequencies of several MHz to several GHz, for example. Then, laser beams subjected to different modulations are incident on the optical fiber bundle 240 through the optical fiber light guide lens 130.

  The optical fiber bundle 240 is a bundle of a plurality of optical fibers. In the example illustrated in FIG. 4A, the optical fiber bundle 240 includes optical fibers 241, 242, and 243. By having the plurality of optical fibers 241, 242, and 243, as shown in FIG. 2, laser light is sequentially irradiated onto a plurality of spots corresponding to the plurality of optical fibers 241, 242, and 243 on the living tissue 500. . Thus, by irradiating a plurality of different spots with laser light, a plurality of laser scans are performed in a narrow region. The return light of the laser light applied to the plurality of spots is guided in the reverse direction by the plurality of optical fibers 241, 242, and 243 and detected by the photodetector 170. Note that in this specification, the “spot” where the living tissue 500 is irradiated with laser light means a region having a predetermined spread where the laser light is irradiated.

  As described above, in this embodiment, the light beam of the laser light is incident on the optical path changing element 164, and the objective lens 165 focuses the light beam of the laser light on a plurality of spots different from each other in the living tissue 500. Here, it is desirable that the laser light passing through the objective lens 165 is basically focused on the optical axis, but the region outside the optical axis cannot be used at all. Therefore, using a region outside the optical axis (for example, a region of about several tens of μm) in the objective lens 165, a laser beam is incident on the objective lens 165, and a plurality of different spots on the living tissue 500 are irradiated. A method becomes possible.

  Here, the laser scanning endoscope apparatus 2 includes a control unit 280 instead of the control unit 180 of the laser scanning endoscope apparatus 1 according to the first embodiment. The control unit 280 has an image signal acquisition unit (light demodulation unit) 281 instead of the image signal acquisition unit 181 with respect to the configuration of the control unit 180. In addition to the function of the image signal acquisition unit 181, the image signal acquisition unit (light demodulation unit) 281 has a function of demodulating the image signal transmitted from the photodetector 170. Here, the image signal acquisition unit (light demodulation unit) 281 can demodulate the image signal by a method corresponding to the laser light modulation method in the optical modulator 230. In the present embodiment, as described above, since the optical modulator 230 frequency-modulates the laser light and multiplexes signals corresponding to a plurality of spots, the image signal acquisition unit (optical demodulation unit) 281 includes the laser The return light by light is demodulated by a method corresponding to the frequency modulation. Therefore, the image signal acquisition unit (light demodulation unit) 281 selectively separates the image signal corresponding to the return light from each spot with respect to the return light of the laser light irradiated to the plurality of spots of the living tissue 500. Can be acquired.

  Here, the plurality of spots irradiated with the laser light on the living tissue 500 are arranged, for example, along the y-axis direction. By arranging the spots on the living tissue 500 in this way and rotating the scanning unit 163 by the rotation mechanism 167 while sequentially irradiating each spot with laser light, the rotation of the scanning unit 163 causes the x-axis direction to rotate. It is possible to simultaneously scan a plurality of lines. As described above, the image signal acquisition unit (light demodulation unit) 281 can selectively separate and acquire the image signal corresponding to the return light from each spot, and thus the laser scanning endoscope apparatus 2. Then, the image information regarding a plurality of scanning lines can be acquired by one rotation of the scanning unit 163. Here, in the laser scanning endoscope apparatus 1 according to the first embodiment, since only one line can be scanned by rotating the scanning unit 163 once, in order to scan a plurality of lines. The rotation of the scanning unit 163 and the parallel movement of the scanning unit 163 (or the endoscope 160 itself) in the y-axis direction have to be repeated. However, in the laser scanning endoscope apparatus 2 according to the second embodiment, the scanning unit 163 necessary for acquiring image data equivalent to that of the laser scanning endoscope apparatus 1 according to the first embodiment. The number of rotations can be further reduced, and the drive mechanism such as a motor included in the rotation mechanism 167 can be reduced in size and power consumption can be reduced.

  The schematic configuration of the laser scanning endoscope apparatus 2 according to the second embodiment of the present disclosure has been described above with reference to FIG. 4A. As described above, according to the laser scanning endoscope apparatus 2 according to the second embodiment, in addition to the effects obtained by the laser scanning endoscope apparatus according to the first embodiment described above, The effect of. That is, in the laser scanning endoscope apparatus 2, a laser beam is incident on the optical path changing element 164, and the objective lens 165 focuses the laser beam on a plurality of different spots of the living tissue 500. To do. Here, the laser light that constitutes the light beam may be laser light that has been modulated differently, and the laser scanning endoscope apparatus 2 has a demodulation function for these laser light, so The image signal corresponding to the return light can be selectively separated and acquired. Therefore, in the laser scanning endoscope apparatus 2, it is possible to scan a plurality of lines by the laser light irradiated to a plurality of spots while the scanning unit 163 rotates once. Therefore, a high scanning speed can be obtained even if the rotational speed of the scanning unit 163 is relatively small.

  For example, as discussed in (2. First Embodiment), it is assumed that one frame of image data is (x × y) = (500 (pixel) × 500 (pixel)). In the laser scanning endoscope apparatus 1 according to the first embodiment, the number of rotations of the scanning unit 163 of about 30000 (rpm) is necessary to realize a scanning speed of 1 fps. However, for example, if the number of spots in the laser scanning endoscope apparatus 2 according to the second embodiment is 5, the number of rotations of the scanning unit 163 necessary to realize the scan speed of 1 fps is 1/5. Therefore, about 6000 (rpm) is sufficient. Therefore, according to the laser scanning endoscope apparatus 2 according to the second embodiment, as described above, an image equivalent to the laser scanning endoscope apparatus 1 according to the first embodiment with a smaller number of rotations. Since information equivalent to data can be obtained, it is possible to reduce the size of a drive mechanism such as a motor included in the rotation mechanism 167 and reduce power consumption.

  In the above description, the optical modulator 230 performs frequency multiplexing by amplitude modulation on the laser light, but the present embodiment is not limited to such an example. For example, the laser beam modulation processing by the optical modulator 230 may be time-division intensity modulation or frequency modulation. The modulation process by the optical modulator 230 may be any process as long as the image signal corresponding to the return light from each spot can be selectively separated and acquired by the demodulation process.

  In the second embodiment, since the region outside the optical axis of the objective lens 165 is used for scanning the laser beam, the objective lens 165 is designed to have a field of view as wide as possible, which is close to the diffraction limit. It is preferable.

  Further, in the above example, by using the optical fiber bundle 240, it is realized that a plurality of spots of the living tissue 500 are irradiated with laser light. However, the second embodiment is not limited to such an example. In the second embodiment, a plurality of laser light irradiation spots may be formed by other methods. For example, by using a multi-core optical fiber having a plurality of cores, the laser light is guided by each core of the multi-core optical fiber, so that a plurality of spots of the living tissue 500 are irradiated with the single optical fiber. It is also possible.

  An example of a multi-core optical fiber is shown in FIG. 4B. FIG. 4B is a schematic diagram illustrating a cross-sectional state of the multi-core optical fiber. Referring to FIG. 4B, the multi-core optical fiber 340 includes a plurality of cores 341 covered with an inner cladding 342 and an outer cladding 343. By guiding laser light through the cores 341 of the multi-core optical fiber 340, the same effect as that obtained when the optical fiber bundle 240 described above is used can be obtained.

  For example, the plurality of cores 341 are preferably arranged in a line at equal intervals in the cross section of the multi-core optical fiber 340. The multi-core optical fiber 340 is arranged so that the arrangement direction of the cores 341 is perpendicular to the rotational scanning direction of the laser light (that is, the arrangement direction of the cores 341 is parallel to the y-axis direction). It is preferable. As a result, the living tissue 500 is irradiated with laser light at a plurality of spots arranged at equal intervals in the y-axis direction. Therefore, the scanning unit 163 rotates to simultaneously scan a plurality of lines in the x-axis direction. Is possible.

  In the example shown in FIG. 4B, the multi-core optical fiber 340 is a double-clad multi-core optical fiber, but the second embodiment is not limited to this example, and the multi-core optical fiber 340 is a single-clad multi-core optical fiber. May be used. However, by using a double-clad multi-core optical fiber, as described above, for example, when performing observation using two-photon excitation, the light collection efficiency of fluorescent light that is return light from the observation target is improved. It becomes possible to make it.

(4. Modifications)
Next, several modified examples of the laser scanning endoscope apparatuses 1 and 2 according to the first and second embodiments of the present disclosure will be described. In the following description of modifications of the first and second embodiments, the laser scanning endoscope apparatus 1 according to the first embodiment will be mainly described as an example, but the following description will be given. The same configuration as that of the modified example can also be applied to the laser scanning endoscope apparatus 2 according to the second embodiment. In addition, the same configuration as that of the following modification example is described in the following (6-2. Laser scanning probe) and the following (6-3. Laser scanning microscope apparatus). The present invention can be applied to a laser scanning microscope apparatus as far as possible.

(4-1. Configuration in which the scanning unit has a plurality of objective lenses)
In the laser scanning endoscope apparatuses 1 and 2 described in (2. First embodiment) and (3. Second embodiment), the scanning unit 163 has one objective lens 165. However, the present embodiment is not limited to such an example, and the scanning unit 163 may include a plurality of objective lenses 165.

  With reference to FIG. 5, a configuration example of a laser scanning endoscope apparatus in the case where such a scanning unit includes a plurality of objective lenses will be described. FIG. 5 is a schematic diagram illustrating a configuration example of a laser scanning endoscope apparatus when the scanning unit includes a plurality of objective lenses. In FIG. 5, in the laser scanning endoscope apparatus, only the endoscope portion is mainly illustrated, and the other portions are not illustrated.

  Referring to FIG. 5, an endoscope 360 according to this modification includes a lens barrel 161, a window unit 162, a scanning unit 363, a rotation mechanism 167, and a parallel movement mechanism 168. Of these configurations, the lens barrel 161, the window portion 162, the rotation mechanism 167, and the parallel movement mechanism 168 are the same as the components described with reference to FIGS. The configuration of the unit 363 will be mainly described, and detailed description thereof will be omitted. In addition, FIG. 5 schematically shows a cross-sectional view of the configuration of the scanning unit 363 of the endoscope 360 and the vicinity thereof when the cross section passes through the central axis of the lens barrel 161 and is parallel to the yz plane. ing.

  The scanning unit 363 includes an optical path changing element 364, a pair of objective lenses 365 and 366, a pair of aberration correction elements 367 and 368, and a housing 369.

  The pair of objective lenses 365 and 366 are provided at positions facing the inner wall of the lens barrel 161 of the scanning unit 363. Further, the pair of objective lenses 365 and 366 are provided at positions facing each other in the scanning unit 363, for example, as shown in FIG. In other words, the pair of objective lenses 365 and 366 may be disposed at a symmetrical position in the scanning unit 363 when viewed from the positive direction of the y-axis, that is, a position rotated by 180 degrees. By arranging the pair of objective lenses 365 and 366 in this manner, as shown in FIG. 5, when one objective lens 365 is positioned in the negative direction of the z-axis and faces the window portion 162, the other The objective lens 366 is located in the positive z-axis direction and faces the inner wall of the lens barrel 161.

  Laser light emitted from the optical fiber 140 and collimated into substantially parallel light by the optical fiber light guide lens 150 is incident on the optical path changing element 364. The optical path changing element 364 changes the optical path of the laser light so that the incident laser light enters at least the objective lenses 365 and 366 facing the window portion 162. For example, the optical path changing element 364 may have a beam splitter function, separate the incident laser light into two, and guide the separated laser light toward the objective lenses 365 and 366, respectively. The optical path changing element 364 is an optical element that can dynamically change the direction of the optical path in synchronization with the rotation of the scanning unit 363. Laser light may be guided toward the head. Note that a specific configuration example of a scanning unit having a plurality of objective lenses like the scanning unit 363 will be described in detail later with reference to FIGS. 6A, 6B, 7A, 7B, 8A, and 8B. explain.

  The pair of aberration correction elements 367 and 368 are disposed in front of the pair of objective lenses 365 and 366, respectively. The functions of the aberration correction elements 367 and 368 are the same as those of the aberration correction element 166 described with reference to FIG. In the example shown in FIG. 5, the pair of aberration correction elements 367 and 368 are disposed between the optical path changing element 364 and the pair of objective lenses 365 and 366, respectively. The positions where the elements 367 and 368 are disposed are not limited to this example, and may be provided anywhere as long as the laser light emitted from the optical fiber 140 passes through the window portion 162.

  The housing 369 accommodates each component of the scanning unit 363 in an internal space. In the present modification, as shown in FIG. 5, the housing 369 has a substantially rectangular parallelepiped shape having a space inside, and an optical path changing element 364 and a pair of aberration correction elements 367 and 368 are disposed in the internal space. Is done. In addition, a pair of objective lenses 365 and 366 are disposed in a part of the surface of the housing 369 facing the inner wall of the lens barrel 161 and facing each other in the housing 369. As described above, the pair of objective lenses 365 and 366 are provided in the housing 369 so that the lens surfaces thereof face each other as shown in FIG. It is assumed that the optical path changing element 364 and the pair of aberration correction elements 367 and 368 are fixed to the housing 369 by a support member (not shown) or the like in the internal space of the housing 369.

  Also in the present modification, the scanning unit 363 can rotate together with the housing 369 about the y axis as a rotation axis by a rotation mechanism (not shown) as in the first embodiment. Further, similarly to the first embodiment, the scanning unit 363 can translate in the y-axis direction together with the housing 369 by a translation mechanism (not shown). As described above, in this modification, the laser light is scanned in the x-axis direction with respect to the living tissue 500 by the rotation of the scanning unit 363 by the rotation mechanism about the y axis, and the scanning unit 363 of the parallel movement mechanism The laser beam is scanned in the y-axis direction with respect to the living tissue 500 by the parallel movement in the y-axis direction.

  The configuration in which the scanning unit 363 includes the plurality of objective lenses 365 and 366 has been described above as a modification of the first and second embodiments of the present disclosure with reference to FIG. 5. According to this modification, scanning of the laser beam by the objective lens 365 and scanning of the laser beam by the objective lens 366 are performed while the scanning unit 363 rotates once. Therefore, compared to the laser scanning endoscope apparatuses 1 and 2 according to the first and second embodiments, the amount of information acquired during one rotation of the scanning unit 363 can be increased. Higher scanning speed is realized. Alternatively, image data having the same amount of information as the laser scanning endoscope apparatuses 1 and 2 according to the first and second embodiments can be acquired with a smaller number of rotations of the scanning unit 363.

  In the example shown in FIG. 5, the scanning unit 363 includes a pair of objective lenses 365 and 366, and the pair of objective lenses 365 and 366 is the scanning unit when viewed from the positive direction of the y axis. Although the case where it arrange | positions in the symmetrical position in 363, ie, the position rotated 180 degree | times was demonstrated, this modification is not limited to this example. The scanning unit 363 may have more than two objective lenses, and the arrangement positions of the plurality of objective lenses are opposed to the inner wall of the lens barrel 161 at substantially the same position in the longitudinal direction of the lens barrel 161. As long as they are arranged at predetermined intervals along the outer peripheral direction of the lens barrel 161, they may be arranged at any position. In the following, referring to FIGS. 6A, 6B, 7A, 7B, 8A, 8B, 9A, and 9B, in the scanning unit having a plurality of objective lenses, the number and arrangement positions of the objective lenses are as follows. A case different from the example shown in FIG. 5 will be described.

(4-1-1. Configuration in which the optical path changing element is a polarization beam splitter)
With reference to FIGS. 6A and 6B, a configuration in which the optical path changing element is a polarization beam splitter will be described as a specific configuration example of the configuration in which the scanning unit includes a plurality of objective lenses. FIG. 6A is a schematic diagram illustrating a configuration example of a scanning unit when the optical path changing element is a polarization beam splitter. FIG. 6B is a schematic diagram illustrating a state when the scanning unit illustrated in FIG. 6A is rotated 180 degrees about the y-axis. 6A and 6B, for the sake of simplicity, only the configuration of the scanning unit and the vicinity thereof is mainly illustrated in the configuration of the laser scanning endoscope apparatus according to the present modification. FIGS. 6A and 6B are cross-sectional views of the configuration of the scanning unit and the vicinity thereof, taken along a cross section passing through the central axis of the barrel and parallel to the yz plane.

  6A and 6B, the scanning unit 370 according to this modification includes a polarization beam splitter 372, a quarter-wave plate 373, a mirror 374, a pair of objective lenses 375 and 376, and a pair of aberration correction elements 377. 378 and a housing 379. In the configuration example shown in FIG. 6A, a polarization modulation element 371 is further provided before the scanning unit 370, that is, immediately before the laser light emitted from the optical fiber enters the scanning unit 370. 6A and 6B, solid and broken arrows indicate the optical path of laser light.

  As in the example shown in FIG. 5, the pair of objective lenses 375 and 376 are arranged at symmetrical positions in the scanning unit 370 when viewed from the y-axis direction, that is, positions rotated by 180 degrees. That is, as shown in FIG. 6A, when one objective lens 375 is positioned in the negative z-axis direction and faces the window portion 162, the other objective lens 376 is positioned in the positive z-axis direction and mirrored. It faces the inner wall of the cylinder 161. In addition, the pair of aberration correction elements 377 and 378 are arranged in front of the pair of objective lenses 375 and 376, respectively. The functions of the aberration correction elements 377 and 378 are the same as those of the aberration correction element 166 described with reference to FIG. 2 and have a function of correcting aberrations that occur when the laser light is focused on the living tissue 500.

  The polarization modulation element 371 has a function of changing the polarization direction of the incident laser light. Specifically, the polarization modulation element 371 may have a function of passing only laser light having a predetermined polarization direction among incident laser light. In the present modification, laser light emitted from a preceding optical fiber (not shown) is incident on the polarization modulation element 371, and the polarization modulation element 371 has a predetermined polarization direction out of the laser light. Only the laser beam having the light beam is allowed to enter and enter the scanning unit 370.

  The laser light that has passed through the polarization modulation element 371 enters the scanning unit 370 and then enters the polarization beam splitter 372. The polarization beam splitter 372 has a function of changing the optical path of laser light having a predetermined polarization direction. Specifically, the polarization beam splitter 372 changes the optical path according to the polarization direction of the incident laser light. In the example shown in FIG. 6A, the polarization beam splitter 372 changes the optical path of the laser light that has passed through the polarization modulation element 371 by approximately 90 degrees, and is applied to the aberration correction element 377 and the objective lens 375 disposed in the negative z-axis direction. It is adjusted to make it enter. The laser light whose optical path has been changed by the polarization beam splitter 372 passes through the aberration correction element 377 and the objective lens 375 and is irradiated onto the living tissue 500 through the window portion 162.

  The housing 379 accommodates each component of the scanning unit 370 in an internal space. In this modification, the housing 379 has a substantially rectangular parallelepiped shape having a space inside, as shown in FIG. 6A, and a polarization beam splitter 372, a quarter wavelength plate 373, a mirror 374 and a pair in the internal space. Aberration correction elements 377 and 378 are arranged. Further, a pair of objective lenses 375 and 376 are disposed in a part of the surface of the housing 379 facing the inner wall of the lens barrel 161 and facing each other in the housing 379. The polarization beam splitter 372, the quarter wavelength plate 373, the mirror 374, and the pair of aberration correction elements 377 and 378 are fixed to the housing 379 by a support member (not shown) or the like in the internal space of the housing 379. Shall.

  Also in this modified example, as in the first embodiment, the scanning unit 370 can rotate together with the housing 379 about the y axis as a rotation axis by a rotation mechanism (not shown). Similarly to the first embodiment, the scanning unit 370 can be translated in the y-axis direction together with the housing 379 by a translation mechanism (not shown). Thus, in this modification, the laser beam is scanned in the x-axis direction with respect to the living tissue 500 by the rotation of the scanning unit 370 by the rotation mechanism about the y axis, and the scanning unit 370 of the parallel movement mechanism The laser beam is scanned in the y-axis direction with respect to the living tissue 500 by the parallel movement in the y-axis direction.

  FIG. 6B shows a state when the scanning unit 370 rotates 180 degrees from the state of FIG. 6A with the y axis as the rotation axis. Since the scanning unit 370 is rotated 180 degrees about the y axis, the positional relationship between the aberration correction element 377 and the objective lens 375 and the aberration correction element 378 and the objective lens 376, and the polarization beam splitter 372 also rotate 180 degrees. ing. That is, in the state illustrated in FIG. 6B, the aberration correction element 378 and the objective lens 376 are opposed to the window portion 162.

  In the state shown in FIG. 6B, the polarization beam splitter 372 passes the laser beam incident through the polarization modulation element 371 from the negative y-axis direction through the optical path as it is, that is, in the positive y-axis direction. It has been adjusted. Alternatively, when the polarization beam splitter 372 is rotated 180 degrees from the state shown in FIG. 6A and is in the state shown in FIG. May be dynamically changed in synchronization with the rotation of the scanning unit 370.

  A quarter wavelength plate 373 and a mirror 374 are provided in this order in the positive direction of the y-axis of the polarization beam splitter 372, and light that has passed through the polarization beam splitter 372 passes through the quarter wavelength plate 373. The light is reflected by the mirror 374, passes through the quarter-wave plate 373 again, and enters the polarizing beam splitter 372 from the positive direction of the y-axis. In this series of optical paths, the laser beam passes through the quarter-wave plate 373 twice, so that its polarization direction is changed. The polarization beam splitter 372 changes the optical path of the laser beam, which is incident from the positive direction of the y axis and whose polarization direction is changed, by approximately 90 degrees, and is incident on the aberration correction element 378 and the objective lens 376 that are positioned in the negative direction of the z axis. It has been adjusted to let The laser light whose optical path has been changed by the polarization beam splitter 372 passes through the aberration correction element 377 and the objective lens 375 and is irradiated onto the living tissue 500 through the window portion 162.

  As described above with reference to FIGS. 6A and 6B, in this modification, the polarization modulation element 371 that controls the polarization direction of the laser light, and the polarization that controls the optical path according to the polarization direction of the laser light. By combining with the beam splitter 372, the laser beam can be guided in the direction of the objective lens 375 or the objective lens 376 facing the window unit 162 in synchronization with the rotation of the scanning unit 370. Therefore, while the scanning unit 370 rotates once, both the scanning of the laser light to the living tissue 500 via the objective lens 375 and the scanning of the laser light to the living tissue 500 via the objective lens 376 can be performed. Therefore, more efficient laser beam scanning is possible.

(4-1-2. Configuration in which optical path changing element is MEMS mirror)
Next, a configuration in which the optical path changing element is a MEMS mirror will be described as a specific configuration example of a configuration in which the scanning unit includes a plurality of objective lenses with reference to FIGS. 7A and 7B. 7A and 7B are schematic diagrams illustrating a configuration example of a scanning unit when the optical path changing element is a MEMS mirror. 7A and 7B, for the sake of simplicity, only the configuration of the scanning unit and the vicinity thereof is mainly illustrated in the configuration of the laser scanning endoscope apparatus according to the present disclosure. FIG. 7A is a cross-sectional view of the configuration of the scanning unit and the vicinity thereof, taken along a cross section that passes through the central axis of the barrel and is parallel to the xz plane. FIG. 7B is a cross-sectional view of the configuration of the scanning unit and its vicinity when the scanning unit is cut by a cross section that passes through the center of the objective lens of the scanning unit and is parallel to the yz plane. 7A corresponds to the cross-sectional view taken along the line BB in FIG. 7A.

  7A and 7B, the scanning unit 380 includes a MEMS mirror 381, a pair of objective lenses 382 and 383, a pair of aberration correction elements 384 and 385, and a housing 386. 7A and 7B indicate the optical path of the laser beam.

  In the example shown in FIG. 7A, the arrangement positions of the pair of objective lenses 382 and 383 are different from the examples shown in FIGS. 5, 6A, and 6B. That is, in the example shown in FIG. 7A, the pair of objective lenses 382 and 383 is not arranged at a position rotated by 180 degrees in the scanning unit 380 when viewed from the y-axis direction, and is a predetermined value smaller than 180 degrees. It is arranged with an angle. In addition, the pair of aberration correction elements 384 and 385 are disposed in front of the pair of objective lenses 382 and 383, respectively. The functions of the aberration correction elements 384 and 385 are the same as those of the aberration correction element 166 described with reference to FIG. 2, and have at least a function of correcting aberrations that occur when laser light is focused on the living tissue. However, also in this modification, the arrangement positions of the objective lenses 382 and 383 and the aberration correction elements 384 and 385 are 180 degrees in the scanning unit 380 when viewed from the y-axis direction, as in FIGS. It may be a rotated position.

  The MEMS mirror 381 is a mirror formed by MEMS, and can dynamically control the reflection direction of incident laser light. Specifically, the MEMS mirror 381 can dynamically change the optical path of the laser light by dynamically changing at least one of the angle and shape of the reflection surface that reflects the incident laser light. . For example, the MEMS mirror 381 is disposed substantially at the center of the inner diameter of the lens barrel 161. The angle and surface shape of the MEMS mirror 381 are such that the laser light emitted from the preceding optical fiber (not shown) is guided in the radial direction of the lens barrel 161, and the laser light is in the circumferential direction of the lens barrel 161. The observation light is dynamically controlled so as to be guided so as to scan along the observation line (that is, to scan the observation object in the x-axis direction).

  Here, in this modified example, as shown in FIGS. 7A and 7B, the housing 386 has a cup shape in which the inside of the cylinder is hollowed out into a cylindrical shape having a smaller diameter. The aberration correction elements 384 and 385 are disposed in the space inside the housing 386, and an objective lens 382, a partial region of a surface of the housing 386 that faces the inner wall of the lens barrel 161 (that is, the outer peripheral surface of the cylinder), 383 are arranged along the outer periphery of the housing 386 at a predetermined interval. Further, the MEMS mirror 381 is not disposed inside the housing 386 but is disposed in a cup-shaped recess so as to be separated from the housing 386. The aberration correction elements 384 and 385 are fixed to the housing 386 by a support member (not shown) or the like in the internal space of the housing 386.

  Also in the present modification, the scanning unit 380 can rotate together with the housing 386 about the y axis as a rotation axis by a rotation mechanism (not shown) as in the first embodiment. Here, in the present modification, as described above, the MEMS mirror 381 is disposed apart from the housing 386, so the MEMS mirror 381 does not rotate even when the scanning unit 380 rotates. In this modification, the MEMS mirror 381 that is an optical path changing element does not rotate with the scanning unit 380, and changes the angle of the reflecting surface and the shape of the surface in synchronization with the rotation of the scanning unit 380, and the window 162 The optical path of the laser beam is changed in the direction of the objective lenses 382 and 383 facing each other. In other words, the laser light is scanned in the living tissue 500 by changing the optical path of the laser light by the MEMS mirror 381. For example, when the scanning unit 380 is rotated by a predetermined angle from the state shown in FIG. Is changed so that the optical path of the laser light is incident on the aberration correction element 385 and the objective lens 383.

  Also in this modified example, the scanning unit 380 can be translated in the y-axis direction together with the housing 386 by a translation mechanism (not shown), as in the first embodiment. When the scanning unit 380 is translated in the y-axis direction, the MEMS mirror 381 may be translated together with the scanning unit 380. As described above, in this modification, the laser light is scanned in the x-axis direction with respect to the living tissue 500 by the polarization of the optical path of the laser light by the dynamic control of the angle and shape of the reflection surface of the MEMS mirror 381 and parallel. The laser beam is scanned in the y-axis direction with respect to the living tissue 500 by the parallel movement of the scanning unit 370 (and the MEMS mirror 381) in the y-axis direction by the moving mechanism.

  However, the MEMS mirror 381 may not move in parallel with the parallel movement of the scanning unit 380 in the y-axis direction. That is, the position of the MEMS mirror 381 may be unchanged with respect to the rotation of the scanning unit 380 with the y axis as the rotation axis and the parallel movement in the y axis direction. Even when the MEMS mirror 381 does not rotate with the scanning unit 380 and does not translate, the MEMS mirror 381 synchronizes with the rotation and translation of the scanning unit 380 to change the angle of the reflection surface and the shape of the surface. By changing and changing the optical path of the laser light in the direction of the objective lenses 382 and 383 facing the window portion 162, the living tissue 500 can be scanned with the laser light.

  It is assumed that the MEMS mirror 381 is supported in a cup-shaped recess of the housing 386 by a support member (not shown) so as not to prevent the above-described driving. For example, the MEMS mirror 381 may be connected to the approximate center (the portion corresponding to the rotation axis of the housing 386) of the bottom surface of the cup-shaped recess of the housing 386 by a support member. Then, by providing the support member with a mechanism for canceling the rotation of the housing 386, a configuration in which the MEMS mirror 381 does not rotate even when the housing 386 rotates can be realized.

  As described above with reference to FIGS. 7A and 7B, in this modification, the living tissue is changed by dynamically changing the conditions (such as the angle and shape of the reflecting surface) of the reflecting surface in the MEMS mirror 381. 500 is scanned with laser light. Since the scanning of the laser beam is controlled by controlling the MEMS mirror 381, laser scanning with a higher degree of freedom can be realized.

  The MEMS mirror 381 is an example of an optical deflection device (optical deflection element) that can dynamically change the reflection direction of light, and even when another optical deflection device is used instead of the MEMS mirror 381. A configuration similar to the configuration described above can be realized, and a similar effect can be obtained. In this modification, the rotation mechanism may not be provided. For example, an objective lens, an aberration correction element, and a MEMS mirror are provided in this order on the optical path of the laser beam in the lens barrel. A window portion is provided at a portion of the outer wall of the lens barrel corresponding to the position where the MEMS mirror is disposed in the longitudinal direction of the lens barrel, and the laser light that has passed through the objective lens and the aberration correction element and is incident on the MEMS mirror is The condition of the reflecting surface of the MEMS mirror is dynamically controlled so that the biological tissue to be observed is scanned in the x-axis direction via the. With such a configuration, it is possible to realize scanning of the observation target in the x-axis direction with respect to the observation target without rotating the constituent members in the lens barrel.

(4-1-3. Configuration in which scanning section has optical path branching element)
Next, with reference to FIGS. 8A and 8B, a configuration in which the scanning unit includes an optical path branching element will be described as a specific configuration example of a configuration in which the scanning unit includes a plurality of objective lenses. 8A and 8B are schematic diagrams illustrating a configuration example of the scanning unit when the scanning unit includes an optical path branching element. 8A and 8B, for the sake of simplicity, only the configuration of the scanning unit and the vicinity thereof is mainly illustrated in the configuration of the laser scanning endoscope apparatus according to the present disclosure. FIG. 8A is a cross-sectional view of the configuration of the scanning unit and the vicinity thereof, taken along a cross section that passes through the central axis of the lens barrel and is parallel to the yz plane. 8B is a cross-sectional view of the configuration of the scanning unit and the vicinity thereof, taken along the line CC shown in FIG. 8A.

  8A and 8B, the scanning unit 390 includes an optical path branching element 391, a lens 392, a lens array 393, optical path changing elements 394a, 394b, 394c, 394d, objective lenses 395a, 395b, 395c, 395d, an aberration correcting element. 396a, 396b, 396c, 396d and a housing 397. As described above, the scanning unit 390 according to this modification includes the four objective lenses 395a, 395b, 395c, and 395d. Further, as shown in FIG. 8B, the four objective lenses 395a, 395b, 395c, and 395d are arranged at positions rotated by 90 degrees in the scanning unit 390 when viewed from the y-axis direction.

  In addition, aberration correction elements 396a, 396b, 396c, and 396d and optical path changing elements 394a, 394b, 394c, and 394d are disposed in front of these objective lenses 395a, 395b, 395c, and 395d, respectively. The functions of the aberration correction elements 396a, 396b, 396c, and 396d are the same as those of the aberration correction element 166 described with reference to FIG. 2, and at least correct the aberration that occurs when the laser light is focused on the living tissue. It has a function. In the example shown in FIGS. 8A and 8B, the optical path changing elements 394a, 394b, 394c, and 394d are, for example, bending mirrors, and have the same function as the optical path changing element 164 described with reference to FIG. That is, the optical path changing elements 394a, 394b, 394c, and 394d guide the laser light incident on the scanning unit 390 to the lens surfaces of the objective lenses 395a, 395b, 395c, and 395d.

  The housing 397 accommodates each component of the scanning unit 390 in an internal space. In this modification, the housing 397 has a substantially rectangular parallelepiped shape having a space inside as shown in FIGS. 8A and 8B. Elements 394a, 394b, 394c, 394d and aberration correction elements 396a, 396b, 396c, 396d are provided. In addition, objective lenses 395a, 395b, 395c, and 395d are disposed in partial areas of four surfaces facing the inner wall of the lens barrel 161 of the housing 397, respectively. The optical path branching element 391, the lens 392, the lens array 393, the optical path changing elements 394a, 394b, 394c, 394d and the aberration correcting elements 396a, 396b, 396c, 396d, and the housing 397 are housed by a support member (not shown). 397 is fixed.

  In this modification, as shown in FIG. 8A, the laser light guided through the lens barrel 161 by an optical fiber (not shown) is collimated into substantially parallel light by the optical fiber light guide lens 150. The light enters the optical path branching element 391 provided on one side of the housing 397. The optical path branch element 391 is a kind of beam splitter, and can split incident laser light into a plurality of optical paths. For example, the optical path branching element 391 may branch the laser light incident by the diffraction grating into a plurality of optical paths. In this modification, the optical path branching element 391 branches the incident laser light into four optical paths.

  The laser light branched into the four optical paths is condensed on the lens array 393 via the lens 392. In the lens array 393, the same number of lenses as the branched laser light are arranged in an array, and each branched laser light is collimated into substantially parallel light by each lens constituting the lens array 393, and the optical path The light enters the change elements 394a, 394b, 394c, and 394d, respectively. The optical path changing elements 394a, 394b, 394c, 394d guide the incident light to the corresponding aberration correction elements 396a, 396b, 396c, 396d and the objective lenses 395a, 395b, 395c, 395d, respectively.

  Also in the present modification, the scanning unit 390 can rotate together with the housing 397 about the y axis as a rotation axis by a rotation mechanism (not shown) as in the first embodiment. Similarly to the first embodiment, the scanning unit 390 can be translated in the y-axis direction together with the housing 397 by a translation mechanism (not shown). As described above, in this modification, the laser light is scanned in the x-axis direction with respect to the living tissue 500 by the rotation of the scanning unit 390 by the rotation mechanism about the y axis, and the scanning unit 390 of the parallel movement mechanism Laser light is scanned in the y-axis direction with respect to the living tissue 500 by parallel movement in the y-axis direction.

  As described above with reference to FIGS. 8A and 8B, in this modification, the laser light incident on the scanning unit 390 is branched into a plurality of, for example, four laser lights by the optical path branching element 391. Then, each of the branched laser beams is guided toward the objective lenses 395a, 395b, 395c, and 395d by the optical path changing elements 394a, 394b, 394c, and 394d. In this modification, the scanning unit 390 rotates about the y-axis as the rotation axis in this state, and thus the living tissue 500 is irradiated with laser light four times via the window unit 162 while the scanning unit 390 rotates once. It will be scanned. Accordingly, the number of lines to be scanned can be increased by one rotation of the scanning unit 390, so that more efficient laser scanning can be performed.

(4-1-4. Configuration in which the incident position of laser light on the lens barrel is fixed)
Next, with reference to FIG. 9A and FIG. 9B, a configuration in which the incident position of the laser beam with respect to the lens barrel is fixed will be described as a specific configuration example of the configuration in which the scanning unit includes a plurality of objective lenses. 9A and 9B are schematic diagrams illustrating a configuration example of the scanning unit when the incident position of the laser beam with respect to the lens barrel is fixed. 9A and 9B, for the sake of simplicity, only the configuration of the scanning unit and the vicinity thereof is mainly illustrated in the configuration of the laser scanning endoscope apparatus according to the present disclosure. FIG. 9A is a cross-sectional view of the configuration of the scanning unit and the vicinity thereof, taken along a cross section that passes through the central axis of the barrel and is parallel to the yz plane. FIG. 9B shows a state in which the configuration of the scanning unit and the vicinity thereof is viewed from the negative y-axis direction (from the direction in which the laser light is incident). However, FIG. 9B illustrates a state in which the scanning unit is rotated by a predetermined angle about the y axis as a rotation axis, and the objective lens is illustrated through the housing of the scanning unit.

  Referring to FIGS. 9A and 9B, the scanning unit 350 includes an incident window unit 351a, 351b, 351c, 351d, an optical path changing element 352a, 352b, 352c, 352d, an objective lens 353a, 353b, 353c, 353d, and an aberration correction element 354a. 354b, 354c, 354d and a housing 355. As described above, the scanning unit 350 according to this modification includes the four objective lenses 353a, 353b, 353c, and 353d. Further, as shown in FIG. 9B, the four objective lenses 353a, 353b, 353c, and 353d are arranged at positions rotated 90 degrees in the scanning unit 350 when viewed from the y-axis direction.

  In addition, aberration correction elements 354a, 354b, 354c, and 354d and optical path changing elements 352a, 352b, 352c, and 352d are disposed in front of these objective lenses 353a, 353b, 353c, and 353d, respectively. The functions of the aberration correction elements 354a, 354b, 354c, and 354d are the same as those of the aberration correction element 166 described with reference to FIG. 2, and at least correct the aberration that occurs when the laser light is focused on the living tissue. It has a function. In the example shown in FIGS. 9A and 9B, the optical path changing elements 352a, 352b, 352c, and 352d are, for example, bending mirrors, and have the same function as the optical path changing element 164 described with reference to FIG. That is, the optical path changing elements 352a, 352b, 352c, 352d guide the laser light incident on the scanning unit 350 to the lens surfaces of the objective lenses 353a, 353b, 353c, 353d.

  The housing 355 accommodates each component of the scanning unit 350 in an internal space. In this modification, the housing 355 has a substantially rectangular parallelepiped shape having a space inside as shown in FIGS. 9A and 9B, and the optical path changing elements 352a, 352b, 352c, 352d, and aberration correction are provided in the internal space. Elements 354a, 354b, 354c, and 354d are disposed. In addition, objective lenses 353 a, 353 b, 353 c, and 353 d are disposed in partial areas of the four surfaces of the housing 397 facing the inner wall of the lens barrel 161. The optical path changing elements 352a, 352b, 352c, and 352d and the aberration correction elements 354a, 354b, 354c, and 354d are fixed to the housing 355 in the internal space of the housing 355 by a support member (not shown). .

  Incident window portions 351a, 351b, 351c, and 351d are formed on the surface of the housing 355 in the negative direction of the y-axis at positions facing the optical path changing elements 352a, 352b, 352c, and 352d, respectively. Here, the housing 355 is formed of a material that does not transmit the laser light in the wavelength band of the incident laser light, and the incident window portions 351a, 351b, 351c, and 351d are formed of a material that transmits the laser light. The Therefore, in this modification, as shown in FIG. 9A, the laser light incident from the negative direction of the y-axis and applied to the scanning unit 350 passes through the incident window portions 351a, 351b, 351c, and 351d of the housing 355. Then, it enters the optical path changing elements 352a, 352b, 352c, 352d inside the housing 355. Here, in FIG. 9A, the laser light guided through the lens barrel 161 by the optical fiber (not shown) is collimated into substantially parallel light by the optical fiber light guide lens (not shown). This is illustrated.

  Also in this modified example, as in the first embodiment, the scanning unit 350 can rotate together with the housing 355 about the y axis as a rotation axis by a rotation mechanism (not shown). Further, similarly to the first embodiment, the scanning unit 350 can be translated in the y-axis direction together with the housing 355 by a translation mechanism (not shown). As described above, in this modification, the laser beam is scanned in the x-axis direction with respect to the living tissue 500 by the rotation of the scanning unit 350 by the rotation mechanism about the y axis, and the scanning unit 350 of the parallel movement mechanism Laser light is scanned in the y-axis direction with respect to the living tissue 500 by parallel movement in the y-axis direction.

  In this modification, the position where the laser beam is incident is fixed with respect to the lens barrel 161. That is, the scanning unit 350 rotates around the y axis as a rotation axis or translates in the y axis direction with the optical axis of the laser beam maintained at a predetermined position with respect to the lens barrel 161. Here, as described above, the incident window portions 351a, 351b, 351c, and 351d are formed in the housing 355 of the scanning unit 350 at positions facing the optical path changing elements 352a, 352b, 352c, and 352d, respectively. Therefore, as shown in FIG. 9B, the scanning unit 350 rotates and the corresponding incident window is positioned at the timing when the incident window portions 351a, 351b, 351c, and 351d are positioned in the region of the laser light irradiation spot S in the housing 355. Laser light enters the housing 355 from the portions 351a, 351b, 351c, and 351d, and scanning is performed.

  Here, in this modification, as shown in FIG. 9B, a case where a plurality of incident window portions 351a and 351d are simultaneously irradiated with laser light can be considered. In this case, when the living tissue 500 is simultaneously irradiated with the laser light incident from the incident window portion 351a and the laser light incident from the incident window portion 351d, the laser light is simultaneously irradiated to two different portions of the biological tissue 500. As a result, the return light from the two locations is detected at the same time, which is not preferable for laser scanning. Accordingly, the beam diameter of the laser light irradiated on the housing 355 (corresponding to the diameter of a circle representing the irradiation spot S shown in FIG. 9B), the sizes of the incident window portions 351a, 351b, 351c, 351d, and the incident window portions 351a, 351b. , 351c, 351d may be designed such that the living tissue 500 is not simultaneously irradiated with laser light incident from different incident window portions 351a, 351b, 351c, 351d. For example, the beam diameter of the laser light may be about 1.5 times the size of the incident window portions 351a, 351b, 351c, and 351d.

  As described above with reference to FIGS. 9A and 9B, in the present modification, the laser light is incident on the scanning unit 350 while the incident position of the laser light is fixed with respect to the lens barrel 161. . In addition, incident window portions 351a, 351b, 352b, 352c, 352d are provided at different positions on the surface of the housing 355 where the laser beam is incident, corresponding to the optical path changing elements 352a, 352b, 352c, 352d provided inside the housing 355. 351c and 351d are formed. In this state, the scanning unit 350 rotates about the y axis as a rotation axis, whereby laser scanning of the living tissue 500 is performed by laser light incident from any of the incident window units 351a, 351b, 351c, and 351d. Therefore, in this modification, the living tissue 500 is scanned with the laser beam four times through the window 162 while the scanning unit 350 makes one rotation. Accordingly, the number of lines to be scanned can be increased by one rotation of the scanning unit 390, so that more efficient laser scanning can be performed. Further, the above-described efficiency in laser scanning (the laser scanning is performed four times while the scanning unit 350 rotates once) is similar to the efficiency of the laser scanning in the scanning unit 390 shown in FIGS. 8A and 8B. As illustrated in FIGS. 9A and 9B, the scanning unit 350 according to the present modification can be configured with fewer components than the scanning unit 390. Therefore, in this modification, in laser scanning, the efficiency comparable to that of the scanning unit 390 shown in FIGS. 8A and 8B can be realized with a simpler configuration.

  The laser scanning endoscope apparatuses 1 and 2 according to the first and second embodiments have been described above with reference to FIGS. 6A, 6B, 7A, 7B, 8A, 8B, 9A, and 9B. As a modification of the above, a specific configuration example of the modification in which the scanning unit has a plurality of objective lenses has been described. As described above, in the present modification, the scanning unit includes a plurality of objective lenses, so that it is possible to perform laser scanning of a plurality of lines with a plurality of objective lenses while the scanning unit rotates once. Become. Therefore, since the number of lines that can be scanned can be increased by one rotation of the scanning unit, more efficient laser scanning is possible.

(4-2. Other configurations)
Next, other modifications of the laser scanning endoscope apparatuses 1 and 2 according to the first and second embodiments of the present disclosure will be described.

(4-2-1. Configuration in which the scanning unit has rotation axes in different directions)
With reference to FIGS. 10A and 10B, a configuration example of a modified example in which the scanning unit has different rotation axis directions will be described. FIG. 10A is a schematic diagram illustrating a configuration example of an endoscope in which a scanning unit has different rotation axis directions. FIG. 10B is a schematic diagram schematically illustrating the configuration of the scanning unit illustrated in FIG. 10A. FIG. 10B is a diagram showing a cross section taken along the line DD in FIG. 10A as viewed from the z-axis direction. However, FIG. 10B illustrates a state in which the scanning unit is rotated by a predetermined angle about the y axis as a rotation axis. Here, the present modification is different from the laser scanning endoscope apparatuses 1 and 2 according to the first and second embodiments shown in FIGS. 2 and 4A in the configuration of the endoscope. The configuration may be the same as that of the laser scanning endoscope apparatuses 1 and 2. Therefore, in the following description of this modification, the configuration of the endoscope which is a difference will be mainly described, and also in FIG. 10A, the configuration of the endoscope among the configurations of the laser scanning endoscope. Mainly illustrated.

  Referring to FIG. 10A, an endoscope 400 according to this modification includes a lens barrel 161, a window portion 162, an optical fiber 140, an optical fiber light guide lens 150, a rotation mechanism 167, a parallel movement mechanism 168, and an optical path changing element 410. And a scanning unit 420 and a rotating member 430. The functions of the lens barrel 161, the window 162, the optical fiber 140, the optical fiber light guide lens 150, the rotation mechanism 167, and the parallel movement mechanism 168 are substantially the same as those of the constituent members described with reference to FIG. Therefore, detailed description is omitted. However, in the present modification, the window portion 162 is provided not at the side wall of the lens barrel 161 but at a front end portion in the longitudinal direction of the lens barrel 161 with a surface substantially perpendicular to the longitudinal direction of the lens barrel 161. That is, the endoscope 400 according to this modification performs laser scanning in a state where one end (tip portion) in the longitudinal direction of the lens barrel 161 is in contact with the living tissue 500. In the present modification, the shape of the window portion 162 may be a curved surface such as a spherical surface or a cylindrical surface, or may be a flat surface. In the example shown in FIGS. 10A and 10B, the window portion 162 has a curved surface having a predetermined curvature.

  In this modification, the laser light guided in the lens barrel 161 by the optical fiber 140 is collimated into substantially parallel light by the optical fiber light guide lens 150 and guided in the y-axis direction through the lens barrel 161. The The head portion of the endoscope 400 is provided with an optical path changing element 410, and the laser light incident on the optical path changing element 410 is changed in the z-axis direction and is incident on the scanning unit 420. The optical path changing element 410 may be any optical element as long as it can change the optical path of the laser beam, and may be a bending mirror, for example.

  The scanning unit 420 includes an optical path changing element 421, an objective lens 422, an aberration correction element 423, and a housing 424. The functions and configurations of the optical path changing element 421, the objective lens 422, the aberration correcting element 423, and the housing 424 are the same as those of the optical path changing element 164, objective lens 165, and aberration correction included in the scanning unit 163 according to the first and second embodiments. Since the function and configuration of the element 166 and the housing 169 are the same, detailed description thereof is omitted. However, in the present embodiment, the scanning unit 420 is configured such that the window unit 162 provided at the distal end of the endoscope 400 and the objective lens 422 are opposed to each other, and the living tissue 500 is laser-transmitted by the objective lens 422 via the window unit 162. It arrange | positions so that light may be condensed. That is, as shown in FIG. 10A, the optical path is changed in the z-axis direction by the optical path changing element 410, and the laser light incident on the scanning unit 420 is changed in the y-axis direction by the optical path changing element 421 in the scanning unit 420. The biological tissue 500 is irradiated through the aberration correction element 423 and the objective lens 422 in this order.

  In the present modification, the scanning unit 420 is mechanically connected to the rotation mechanism 167 via the rotation member 430, and rotates about the z axis as the rotation axis by the rotation mechanism 167. The scanning unit 420 rotates around the z axis as a rotation axis in a state where the scanning unit 420 irradiates the living tissue 500 with laser light, so that the distal end portion of the endoscope 400 is in the x-axis direction with respect to the living tissue 500. The laser beam can be scanned. In this modification, the translation mechanism 168 translates the scanning unit 420 in the z-axis direction. Therefore, in this modification, laser scanning in the xz plane is performed on the living tissue 500.

  Here, the rotating member 430 includes a plurality of shafts 431 and 432. The shaft 431 extends along the longitudinal direction of the lens barrel 161 in the lens barrel 161, and one end thereof is connected to the rotation mechanism 167. The shaft 431 is rotated by the rotation mechanism 167 using the y axis as a rotation axis. A gear (gear) mechanism is provided at the other end of the shaft 431, and is connected to one end of a shaft 432, which is also provided with a gear mechanism, by meshing the gear mechanism. The shaft 432 extends in the z-axis direction, which is approximately 90 degrees from the longitudinal direction of the lens barrel 161, in the lens barrel 161, and one end of the shaft 432 is connected to the shaft 431 via the gear mechanism as described above. The end is connected to the scanning unit 420. By connecting the rotation mechanism 167 and the rotation member 430 in this way, the rotation motion about the y axis as the rotation axis by the rotation mechanism 167 is finally transmitted to the scanning unit 420 as the rotation motion about the z axis as the rotation axis. Is done. Therefore, the rotation mechanism 167 can rotate the scanning unit 420 about the z axis as a rotation axis.

  In this modification, the configurations of the rotation mechanism 167 and the rotation member 430 are not limited to this example, and any configuration may be used as long as the scanning unit 420 can be rotated about the z axis as a rotation axis.

  As described above, with reference to FIGS. 10A and 10B, as a modification of the laser scanning endoscope apparatuses 1 and 2 according to the first and second embodiments, a modification in which the scanning unit has different rotation axis directions. The configuration example has been described. According to this modification, the window portion 162 is provided at the distal end portion in the longitudinal direction of the lens barrel 161 with a surface substantially perpendicular to the longitudinal direction of the lens barrel 161. Then, laser scanning is performed on the part where the tip of the lens barrel 161 is brought into contact. Therefore, for example, even when the site to be observed exists in a recessed portion in the body cavity where it is difficult to contact the side wall of the lens barrel 161, observation by laser scanning can be performed. .

  An endoscope 160 in which a window portion 162 is provided on the side wall of the lens barrel 161 as in the laser scanning endoscope apparatuses 1 and 2 according to the first and second embodiments, and a mirror as in this modification. The endoscope 400 in which the window portion 162 is provided at the distal end portion of the cylinder 161 may be replaceable with respect to the same apparatus main body portion, for example. Whether to use a configuration in which the window portion 162 is provided on the side wall of the lens barrel 161 or a configuration in which the window portion 162 is provided at the distal end portion of the lens barrel 161 is used as an endoscope according to the shape of the observation target site, etc. , May be appropriately selected by the user.

(4-2-2. Modification in which a plurality of objective lenses are arranged in the longitudinal direction of the lens barrel)
In the modification described in (4-1. Configuration in which the scanning unit includes a plurality of objective lenses), the plurality of objective lenses are arranged in the circumferential direction of the lens barrel 161 at substantially the same position in the longitudinal direction of the lens barrel 161. The case where they are arranged side by side has been described. However, the present embodiment is not limited to such an example. For example, a plurality of objective lenses may be arranged side by side along the longitudinal direction of the lens barrel 161.

  With reference to FIG. 11, a modified example in which a plurality of objective lenses are arranged in the longitudinal direction of the lens barrel will be described. FIG. 11 is a schematic diagram illustrating a configuration example of an endoscope according to a modification example in which a plurality of objective lenses are arranged in the longitudinal direction of the lens barrel.

  Referring to FIG. 11, an endoscope 450 according to this modification includes a lens barrel 161, a window unit 162, a rotation mechanism 167, a parallel movement mechanism 168, and a scanning unit 460. The functions of the lens barrel 161, the window portion 162, the rotation mechanism 167, and the parallel movement mechanism 168 are the same as those of the constituent members described with reference to FIG. Although not shown in FIG. 11 for simplicity, the endoscope 450 has the same configuration as the optical fiber 140 and the optical fiber light guide lens 150 included in the endoscope 160 shown in FIG. ing. The laser light guided through the lens barrel 161 by the optical fiber is collimated into substantially parallel light by the optical fiber light guide lens, guided through the lens barrel 161 in the y-axis direction, and incident on the scanning unit 460. Will be.

  The scanning unit 460 according to this modification includes an aberration correction element 461, a first optical path changing element 463, a second optical path changing element 464, a first objective lens 465, a second objective lens 466, Is housed in the housing 469. As shown in FIG. 11, in this modification, the first objective lens 465 and the second objective lens 466 are directed in substantially the same direction along the longitudinal direction of the lens barrel 161 (that is, the lens barrel 161). Are arranged side by side in substantially the same position in the circumferential direction. A first optical path changing element 463 and a second optical path changing element 464 are provided so as to correspond to the first objective lens 465 and the second objective lens 466, respectively. The functions and configurations of the aberration correction element 461 and the housing 469 are the same as those of the aberration correction element 166 and the housing 169 shown in FIG. The functions and configurations of the first objective lens 465 and the second objective lens 466 are the same as the functions and configuration of the objective lens 165 shown in FIG.

  The first optical path changing element 463 is, for example, a beam splitter, and guides a part of the laser light guided in the lens barrel 161 to the second optical path changing element 464 in the subsequent stage and a part thereof. The light is guided toward the first objective lens 465 provided corresponding to the above. The second optical path changing element 464 is, for example, a bending mirror, and guides the laser light transmitted through the first optical path changing element 463 in the preceding stage toward the second objective lens 466 provided corresponding to the second optical path changing element 464. . The laser beams whose optical paths are changed by the first optical path changing element 463 and the second optical path changing element 464 pass through the first objective lens 465 and the second objective lens 466, respectively, and are observed through the window portion 162. The target living tissue (not shown) is irradiated. As described above, in the present modification, the living tissue is irradiated with the laser light at two different spots in the y-axis direction. Also in this modified example, similarly to the scanning unit 163 of the endoscope 160 illustrated in FIG. 2, the scanning unit 460 is rotated by the rotation mechanism 167 with the y-axis direction as the rotation axis direction, and the translation mechanism 168 is rotated in the y-axis direction. Translated to. Therefore, in the endoscope 450 according to the present modification, a plurality of laser beams are irradiated to a plurality of spots in the y-axis direction (two spots in the example illustrated in FIG. 11) while the scanning unit 460 rotates once. The line can be scanned.

  In order to distinguish an optical signal obtained by irradiating a plurality of spots with laser light, laser light whose wavelength, angle, polarization, or the like is temporally modulated is incident on the first optical path changing element 463, and The transmission and reflection of the laser light at the first optical path changing element 463 may be controlled in accordance with the modulation of the laser light. Examples of the first optical path changing element 463 that can be used for such control include a dichroic mirror (an example of an optical element that separates laser light according to wavelength), a volume holographic diffraction element (laser light according to angle), and the like. And an optical element such as a polarization beam splitter (an example of an optical element that separates laser light in accordance with polarization). Moreover, it is desirable that the laser light incident on the first optical path changing element 463 and the second optical path changing element 464 is as close to parallel light as possible so that the observation depth in the living tissue does not change.

  Here, in the endoscope 160 shown in FIG. 2, when the laser beam is scanned in the y-axis direction, the scanning unit 163 is moved in the y-axis direction by the parallel movement mechanism 168. Therefore, in order to increase the field of view in the y-axis direction, the stroke of the scanning unit 163 in the y-axis direction must be increased. In order to keep the position accuracy of the optical system of the scanning unit 163 with high accuracy while driving the scanning unit 163 at a high speed when the stroke is large, mechanical rigidity required for the axis guide, the feed mechanism, etc. Thus, the required accuracy for each member becomes higher. On the other hand, according to the present modification, the first objective lens 465 and the second objective lens 466 are provided side by side in the y-axis direction, so that a plurality of spots in the y-axis direction are irradiated with laser light. Is possible. Therefore, the field of view in the y-axis direction can be further widened without increasing the stroke of the scanning unit 460 by the translation mechanism 168. The configuration according to the present modification can be suitably applied particularly when the field in the y-axis direction is wider than the aperture size of the objective lens.

  FIG. 12 shows another configuration example of the endoscope according to the present modification example shown in FIG. FIG. 12 is a schematic diagram illustrating another configuration example of an endoscope according to a modification example in which a plurality of objective lenses are arranged in the longitudinal direction of the lens barrel. Referring to FIG. 12, an endoscope 470 according to the present modification includes a lens barrel 161, a window unit 162, a rotation mechanism 167, a parallel movement mechanism 168, and a scanning unit 480. The scanning unit 480 includes an aberration correction element 461, a first optical path changing element 463, a second optical path changing element 464, a first objective lens 465, and a second objective lens 466. It is stored in 469 and configured. Referring to FIG. 12, an endoscope 470 according to this modification includes a first objective lens 465 and a second objective lens 466 arranged along the longitudinal direction of the lens barrel 161 and substantially the same. They are arranged in directions different by 180 degrees (that is, at positions rotated approximately 180 degrees in the circumferential direction of the lens barrel 161). Other configurations are the same as those of the endoscope 450 described with reference to FIG. 11, and thus detailed description thereof is omitted.

  In the endoscope 470 shown in FIG. 12, based on the rotation phase of the scanning unit 480, it is distinguished whether the living tissue is irradiated with the laser light by the first objective lens 465 or the second objective lens 466. Therefore, by detecting the return light from the living tissue in synchronization with the rotation of the scanning unit 480, it is not necessary to perform the modulation of the laser light for distinguishing the signals as described above.

  The modification example in which a plurality of objective lenses are arranged in the longitudinal direction of the lens barrel has been described above with reference to FIGS. 11 and 12. As described above, in the present modification, the first objective lens 465 and the second objective lens 466 are provided side by side in the y-axis direction, so that a plurality of spots in the y-axis direction are irradiated with laser light. It becomes possible to do. Therefore, the field of view in the y-axis direction can be further widened without increasing the stroke of the scanning unit 460 by the translation mechanism 168. Further, as shown in FIGS. 11 and 12, in the present modification, the first objective lens 465 and the second objective lens 466 may be disposed in substantially the same direction, or may be in different directions. It may be arranged facing. The arrangement positions of the first objective lens 465 and the second objective lens 466 are not limited to the examples shown in FIGS. 11 and 12, and a plurality of objective lenses are spirally formed along the longitudinal direction of the lens barrel 161. It may be arranged.

  In this modification, astigmatism correction that can dynamically change the correction amount of astigmatism as described in the following (6-2-2. Astigmatism correction element) is used as the aberration correction element 461. An element (an active astigmatism correction element described later) may be used. By using the active astigmatism correction element and adjusting the correction amount by the active astigmatism correction element in synchronization with the rotation of the scanning units 460 and 480, aberrations caused by relative alignment errors of a plurality of objective lenses, etc. Can reduce the effects of

(5. Configuration of aberration correction element)
Next, a specific configuration of the aberration correction element 166 shown in FIGS. 2 and 3 will be described. As described above (2. First Embodiment), the aberration correction element 166 according to the present embodiment corrects aberrations that occur when laser light is focused on the living tissue 500. Examples of such aberration include chromatic aberration, spherical aberration, coma and astigmatism.

  Among these aberrations, for chromatic aberration, laser light having a specific wavelength band, such as near infrared light, is often used when observing living tissue as in this embodiment. The influence of the chromatic aberration is considered to be relatively small. For spherical aberration caused by the window 162, for example, the objective lens 165 is an aspheric lens, and the spherical surface is adjusted by adjusting optical characteristics such as curvature, thickness, aspheric coefficient, etc. of the aspheric lens. It is possible to substantially correct the aberration. Therefore, in the following, a specific configuration of the aberration correction element 166 for correcting astigmatism caused by the objective lens 165 and the window unit 162 among aberrations will be mainly described. However, in the present embodiment, an element for correcting chromatic aberration and an element for correcting spherical aberration may be further provided separately from the element for correcting astigmatism. For example, when the wavelength bands of excitation light (light irradiated to the biological tissue 500) and biological signal light (return light from the biological tissue 500) are different, such as in fluorescence observation, the return light is efficiently guided to the fiber. In addition, it is desirable to separately provide an element for correcting chromatic aberration. For example, in order to correct the spherical aberration due to the thickness of the window part or the living tissue, a spherical aberration correction element may be separately provided in addition to adjusting the optical characteristics of the objective lens 165 described above.

  As described in (2. First embodiment), the laser scanning observation apparatus according to this embodiment may be provided with an observation depth adjustment mechanism for changing the observation depth. . In a laser scanning observation apparatus provided with such an observation depth adjustment mechanism, an aberration correction element that corrects astigmatism, which is designed in consideration of aberration fluctuations accompanying changes in observation depth, is preferably applied. Can be done. Further, as described above, the chromatic aberration is corrected when the laser scanning endoscope apparatus 1 performs observation using fluorescence such as two-photon excitation or when observation is performed using a plurality of laser beams having different wavelengths. An aberration correction element can be suitably applied. The specific configuration of the aberration correction element in the case of having such an observation depth adjusting mechanism or performing observation using two-photon excitation will be described in detail in the following (6-2. Laser scanning probe). explain.

(5-1. Correction of astigmatism)
A specific configuration example of an aberration correction element for correcting astigmatism will be described. Prior to describing the specific configuration of the aberration correction element for correcting astigmatism, the contents of the study by the present inventors regarding astigmatism will be described.

  As described in (2. First Embodiment) above, the degree of aberration caused by the objective lens 165 and the window portion 162 is affected by the NA value of the objective lens 165 and the shape of the window portion 162. The Specifically, the higher the NA of the objective lens 165, the greater the thickness of the component of the window portion 162, and the smaller the curvature of the window portion 162 (that is, the smaller the diameter (outer diameter) of the lens barrel 161). ), The degree of the aberration tends to increase.

  The present inventors repeatedly perform a ray tracing simulation while changing the above three parameters (the NA of the objective lens 165, the thickness of the window portion 162, and the diameter of the lens barrel 161). The relationship with the degree of astigmatism was investigated in more detail, and a configuration for correcting astigmatism was studied. The astigmatism referred to here means the difference between the focal length in the x-axis direction and the focal length in the y-axis direction shown in FIGS.

  As a result of the above examination, the degree of astigmatism increases in proportion to the square of the optical distance of the distance in the depth direction (the product of the refractive index of the medium and the distance in the depth direction), and the objective lens 165 The knowledge that it increases in proportion to the square of NA is obtained. Further, it has been confirmed that the degree of astigmatism increases as the diameter of the lens barrel 161 (that is, the outer diameter of the window portion 162) decreases.

  In view of the above findings, the present inventors have studied a configuration for correcting astigmatism. Hereinafter, with reference to FIG. 13A, FIG. 13B, FIG. 14, and FIG. 15, a specific configuration example of the aberration correction element conceived by the present inventors as a result of the above examination will be described. Here, when the spherical aberration is corrected by adjusting the optical characteristics of the objective lens 165 that is an aspheric lens as described above, for example, the component of the spherical aberration in either the x-axis direction or the y-axis direction. The parameters of the optical characteristics of the objective lens 165 can be adjusted so as to minimize. Therefore, the inventors of the present invention are not limited to the spherical aberration in the y-axis direction (that is, the yz plane) shown in FIGS. 2 and 3, which is a direction in which the window portion 162 having a cylindrical shape can be regarded as a parallel plate. It was considered that correction was performed by adjusting the optical characteristics of the objective lens 165, and that spherical aberration in the xz plane was corrected together with a configuration for correcting astigmatism. Therefore, a specific configuration example of the aberration correction element described below is an example of a configuration having a function of correcting astigmatism and correcting spherical aberration in the xz plane.

  13A to 15 shown below correspond to the illustration of the scanning unit 163 of the endoscope 160 shown in FIGS. 2 and 3 and the state of the vicinity thereof. Specifically, FIGS. 13A to 15 mainly illustrate the window 162, the optical path changing element 164, the objective lens 165, the aberration correcting element 166, and the living tissue 500 in the configuration shown in FIGS. The configuration of the aberration correction element 166 is illustrated more specifically. The functions and configurations of the window portion 162, the optical path changing element 164, and the objective lens 165 shown in FIGS. 13A to 15 are the same as the functions and configurations of these components described with reference to FIGS. Therefore, in the following, detailed description of these components will be omitted, and the specific configuration of the aberration correction element 166 will be mainly described. In the following description of the specific configuration of the aberration correction element 166, the case where the optical path changing element 164 is a bending mirror and the objective lens 165 is an aspherical lens will be described. In addition, each concrete structure of the aberration correction element shown below is applicable also as each aberration correction element shown to FIGS. 5-10B.

(5-1-1. Cylindrical concave-convex lens pair)
With reference to FIGS. 13A and 13B, a cylindrical concavo-convex lens pair, which is one configuration example of an aberration correction element for correcting astigmatism and spherical aberration in the xz plane, will be described. FIG. 13A and FIG. 13B are schematic views illustrating the configuration of a cylindrical concave / convex lens pair which is an example of the configuration of the aberration correction element 166 according to the present embodiment. FIG. 13A illustrates a state in which the scanning unit 163 of the endoscope 160 illustrated in FIG. 2 and the vicinity thereof are viewed from the positive direction of the z-axis. FIG. 13B illustrates a state in which the scanning unit 163 of the endoscope 160 illustrated in FIG. 2 and the vicinity thereof are viewed from the positive direction of the y-axis. However, in FIG. 13A, the objective lens 165 is illustrated through the optical path changing element 164. In FIG. 13A and FIG. 13B, for the sake of simplicity, only the straight lines necessary for the explanation are mainly shown as the straight lines representing the laser beam.

  Referring to FIG. 13A, in this configuration example, a cylindrical concave / convex lens pair 620 is disposed in front of the optical path changing element 164. The cylindrical concave / convex lens pair 620 includes a concave cylindrical lens 621 having a concave lens surface and a convex cylindrical lens 622 having a convex lens surface. The cylindrical concave / convex lens pair 620 corresponds to the aberration correction element 166 shown in FIGS. 2 and 3, and is an aberration correction element for correcting astigmatism and spherical aberration in the xz plane. In the present embodiment, the cylindrical concave / convex lens pair 620 is disposed upstream of the optical path changing element 164, that is, upstream of the objective lens 165, as shown in FIG. 13A.

  The concave cylindrical lens 621 has a cylindrical surface in which one surface is flat and the other surface facing the one surface is concave. Then, as shown in FIG. 13A, the plane having a flat surface faces the negative direction of the y-axis, that is, the direction in which the laser light enters, and the surface having the concave cylindrical surface faces the negative direction of the y-axis. Established. The concave cylindrical lens 621 is disposed so that the z-axis direction is the cylindrical axial direction of the cylindrical surface.

  The convex cylindrical lens 622 has a cylindrical surface in which one surface is a flat surface and the other surface facing the one surface is a convex shape. Then, as shown in FIG. 13A, the surface having a convex cylindrical surface is oriented in the negative direction of the y axis, that is, the direction in which the laser light is incident, and the surface having a flat surface is oriented in the positive direction of the y axis. Established. That is, the concave cylindrical lens 621 and the convex cylindrical lens 622 are disposed so that the convex cylindrical surface of the convex cylindrical lens 622 and the concave cylindrical surface of the concave cylindrical lens 621 face each other. Further, the convex cylindrical lens 622 is arranged so that the z-axis direction is the cylindrical axial direction of the cylindrical surface.

  Referring to FIGS. 13A and 13B, the light beam of the laser beam is illustrated by a straight line. Further, the laser light collimated into substantially parallel light and guided in the y-axis direction passes through the cylindrical concave / convex lens pair 620, and its optical path is changed in the z-axis direction by the optical path changing element 164, and the objective lens 165, window A state in which the living tissue 500 is irradiated through the part 162 in order is illustrated. As described above, in this configuration example, the incident laser light sequentially passes through the plane of the concave cylindrical lens 621, the concave cylindrical surface, the convex cylindrical surface of the convex cylindrical lens 622, and the plane, thereby changing the optical path changing element. 164 is incident. By arranging the cylindrical uneven lens pair 620 as shown in FIG. 13A, astigmatism and spherical aberration in the xz plane can be corrected. The cylindrical concavo-convex lens pair 620 is rotated and / or translated together with the scanning unit by a rotation mechanism (not shown) and / or a translation mechanism (not shown).

  Here, the optical characteristics (for example, material, thickness, curvature of the cylindrical surface, etc.) and the specific configuration of the cylindrical concave / convex lens pair 620 include the wavelength band of the incident laser light, the optical characteristics of the objective lens 165, and the window portion 162. It may be set appropriately according to the optical characteristics of For example, in order to minimize astigmatism and spherical aberration in the xz plane, the curvature of the cylindrical surface of the concave cylindrical lens 621 and the curvature of the cylindrical surface of the convex cylindrical lens 622, the magnitude relationship between the curvatures of both, the concave cylindrical lens 621 The thickness of the convex cylindrical lens 622 in the optical axis direction (y-axis direction), the interval between the concave cylindrical lens 621 and the convex cylindrical lens 622, and the like may be adjusted.

(5-1-2. Cylindrical meniscus lens)
With reference to FIG. 14, a cylindrical meniscus lens which is one configuration example of an aberration correction element for correcting astigmatism and spherical aberration in the xz plane will be described. FIG. 14 is a schematic diagram illustrating a configuration of a cylindrical meniscus lens that is one configuration example of the aberration correction element 166 according to the present embodiment. FIG. 14 illustrates a state in which the scanning unit 163 of the endoscope 160 illustrated in FIG. 2 and the vicinity thereof are viewed from the positive direction of the y-axis. In FIG. 14, for the sake of simplicity, only the straight lines necessary for explanation are mainly shown as the straight lines representing the laser light flux.

  Referring to FIG. 14, in this configuration example, a cylindrical meniscus lens 630 is disposed between the objective lens 165 and the window portion 162. The cylindrical meniscus lens 630 corresponds to the aberration correction element 166 shown in FIGS. 2 and 3 and is an aberration correction element having a function of correcting astigmatism and spherical aberration in the xz plane.

  The cylindrical meniscus lens 630 is a meniscus lens having cylindrical surfaces on both sides. As shown in FIG. 14, the cylindrical surfaces on both sides of the cylindrical meniscus lens 630 are formed so that the same direction is the axial direction of the cylinder, and the curvatures of the cylindrical surfaces on both sides have the same sign. In the present configuration example, as shown in FIG. 14, in the cylindrical meniscus lens 630, the cylindrical axial direction of the cylindrical surface is in the y-axis direction, that is, in the same direction as the cylindrical axial direction of the cylindrical surface of the window portion 162. It arrange | positions so that it may become. However, the cylindrical meniscus lens 630 is disposed such that the curvature of the cylindrical surface has a sign opposite to the curvature of the cylindrical surface of the window portion 162. In the example shown in FIG. 14, the cylindrical surfaces on both sides of the cylindrical meniscus lens 630 are formed such that the curvature of the cylindrical surface facing the objective lens 165 is larger than the curvature of the cylindrical surface facing the window portion 162. ing.

  Referring to FIG. 14, the laser light beam is shown as a straight line. Further, the laser beam collimated by the substantially parallel light and guided in the y-axis direction is changed in the optical path by the optical path changing element 164 in the z-axis direction, and the objective lens 165, the cylindrical meniscus lens 630, and the window part 162 are sequentially changed. The state of passing through and irradiating the living tissue 500 is shown. As described above, in this configuration example, the cylindrical meniscus lens 630 is disposed between the objective lens 165 and the window portion 162, whereby astigmatism and spherical aberration in the xz plane can be corrected. The cylindrical meniscus lens 630 rotates and / or translates together with the scanning unit by a rotation mechanism (not shown) and / or a translation mechanism (not shown).

  Here, the optical characteristics (for example, material, thickness, curvature of the cylindrical surface, etc.) and specific configuration of the cylindrical meniscus lens 630 include the wavelength band of the incident laser light, the optical characteristics of the objective lens 165, and the window 162. It may be set appropriately according to the optical characteristics and the like. For example, in the example shown in FIG. 14, the cylindrical meniscus lens 630 is formed such that the curvature of the cylindrical surface facing the objective lens 165 is larger than the curvature of the cylindrical surface facing the window 162. The curvature relationship is not limited to this example. The values and magnitude relationships of the curvatures of the cylindrical surfaces on both sides of the cylindrical meniscus lens 630 may be adjusted so as to minimize high-order aberrations such as astigmatism and spherical aberration in the xz plane.

  As described above, the degree of astigmatism varies depending on the optical distance in the observation depth direction (the product of the refractive index of the medium and the distance in the depth direction). When using a lens system having cylindrical surfaces on at least two surfaces, such as the cylindrical concave / convex lens pair 620 and the cylindrical meniscus lens 630 described above, observation is performed by appropriately adjusting the curvature and shape of curved surfaces on both surfaces. It is possible to realize an astigmatism correction element that corrects the astigmatism with a correction amount corresponding to the fluctuation of astigmatism accompanying a change in depth. Therefore, when the laser scanning observation apparatus according to the present embodiment includes an observation depth adjustment mechanism, the cylindrical concave / convex lens pair 620 and the cylindrical meniscus described above are used as astigmatism correction elements for correcting astigmatism. A configuration as exemplified by the lens 630 can be suitably applied. Details of the astigmatism correction element in consideration of the dependency of astigmatism on the observation depth will be described in detail in (6-2-2. Astigmatism correction element) below.

(5-1-3. Cylindrical plano-concave lens)
With reference to FIG. 15, a cylindrical plano-convex lens which is one configuration example of an aberration correction element for correcting astigmatism and spherical aberration in the xz plane will be described. FIG. 15 is a schematic diagram showing a configuration of a cylindrical plano-convex lens which is a configuration example of the aberration correction element 166 according to the present embodiment. FIG. 15 illustrates a state in which the scanning unit 163 of the endoscope 160 illustrated in FIG. 2 and the vicinity thereof are viewed from the positive direction of the y axis. In FIG. 15, for the sake of simplicity, only the straight lines necessary for explanation are mainly shown as the straight lines representing the laser light flux.

  Referring to FIG. 15, in this configuration example, a cylindrical plano-convex lens 640 is disposed between the objective lens 165 and the window portion 162. The cylindrical plano-convex lens 640 corresponds to the aberration correction element 166 shown in FIGS. 2 and 3 and is an aberration correction element having a function of correcting astigmatism and spherical aberration in the xz plane.

  The cylindrical plano-convex lens 640 is a lens having a cylindrical surface on one surface and a flat surface on the other surface facing the one surface. As shown in FIG. 15, the cylindrical plano-convex lens 640 is disposed so that the plane faces the objective lens 165 and the cylindrical surface faces the window portion 162. The cylindrical plano-convex lens 640 is arranged so that the cylindrical axis direction of the cylindrical surface is the same as the y-axis direction, that is, the axial direction of the cylindrical surface cylinder of the window portion 162. Further, as shown in FIG. 15, the cylindrical plano-convex lens 640 is disposed close to the window portion 162.

  Referring to FIG. 15, the light beam of the laser beam is illustrated by a straight line. Further, the laser light collimated by the substantially parallel light and guided in the y-axis direction is changed in the z-axis direction by an optical path changing element (not shown), and an objective lens 165, a cylindrical plano-convex lens 640, A state in which the living tissue 500 is irradiated through the window part 162 in order is illustrated. As described above, in the present configuration example, the cylindrical plano-convex lens 640 is disposed at a position between the objective lens 165 and the window portion 162 and close to the window portion 162, so that astigmatism and x Spherical aberration in the −z plane can be corrected. The cylindrical plano-convex lens 640 rotates and / or translates together with the scanning unit by a rotation mechanism (not shown) and / or a translation mechanism (not shown).

  Here, the optical characteristics (for example, material, thickness, curvature of the cylindrical surface, etc.) and specific configuration of the cylindrical plano-convex lens 640 include the wavelength band of the incident laser beam, the optical characteristics of the objective lens 165, and the window 162. It may be set appropriately according to the optical characteristics and the like. For example, the thickness of the cylindrical plano-convex lens 640 in the z-axis direction, the curvature of the cylindrical surface, the proximity distance to the window portion 162, and the like are such that astigmatism and spherical aberration in the xz plane are minimized. May be adjusted.

  The specific configuration example of the aberration correction element 166 shown in FIGS. 2 and 3 has been described above with reference to FIGS. 13A to 15. Here, the specific configuration example of the aberration correction element 166 has been described above by taking the configuration according to the first embodiment shown in FIGS. 2 and 3 as an example. However, the above-described aberration correction element is applied. The configuration to be performed is not limited to such an example. The above-described aberration correction element, which is the cylindrical concave / convex lens pair 620, the cylindrical meniscus lens 630, and the cylindrical plano-convex lens 640, is the second embodiment described in the above (3. Second Embodiment) or the above (4. It can be applied as an aberration correction element in the configuration according to each modification described in (Modification). In addition, the aberration correction element according to the present embodiment is not limited to the above-described configuration, and may be an arbitrary configuration configured by known optical members such as various lenses and a refractive index matching medium. In the above description, the specific configuration of the aberration correction element that corrects spherical aberration and astigmatism among aberrations has been described. However, the aberration correction element according to the present embodiment is not limited to this example. The aberration correction element according to the present embodiment may have a configuration for correcting other types of aberration, and may be a combination of a plurality of configurations for correcting different types of aberration. May be. Further, when designing the configuration of the aberration correction element according to the present embodiment, in addition to the optical characteristics described above, a change in aberration due to the shift of the objective lens in the z-axis direction and higher-order aberrations (for example, 4 It is desirable to design in consideration of rotationally symmetric high-order astigmatism.

(6. Configuration with observation depth adjustment mechanism)
The laser scanning observation apparatus according to the present embodiment may be provided with an observation depth adjustment mechanism for changing the observation depth. Since the laser scanning observation device has an observation depth adjustment mechanism, it is possible to perform laser scanning in the depth direction with respect to the observation target, thereby realizing useful observation that better meets the needs of the user. The

  As the observation depth adjustment mechanism, for example, in the optical axis direction of a collimator lens (corresponding to the optical fiber light guide lens 150 shown in FIG. 2) that makes the light emitted from the optical fiber substantially parallel and guides it to the scanning unit. Movement mechanism, movement mechanism of the objective lens in the optical axis direction, focal length adjustment mechanism by configuring the objective lens with a variable focus lens, movement mechanism of the end position of the optical fiber in the housing in the optical axis direction, etc. Is mentioned. In addition, the observation depth may be changed by providing a plurality of regions each having a different thickness in the window portion that is in contact with the observation target and changing the region that is in contact with the observation target.

  On the other hand, when the observation depth is changed, the convergence state and divergence state of the laser light in the objective lens and the window portion change, so the degree of astigmatism when the laser light is focused on the observation target is also increased. Change. Therefore, in this embodiment, when the laser scanning observation apparatus has an observation depth adjustment mechanism, the astigmatism is corrected with a correction amount corresponding to the fluctuation of astigmatism accompanying the change in the observation depth. An astigmatism correction element is preferably provided.

  Hereinafter, the laser scanning method using the observation depth adjustment mechanism and the configuration of the laser scanning observation apparatus equipped with the astigmatism correction element corresponding to the change of the observation depth will be described in detail. In the following, as in the first embodiment described above, the configuration of the laser scanning observation apparatus when a single spot is irradiated with laser light on the observation target will be described. However, each configuration shown below is not limited to such an example, and similarly to the second embodiment, for example, by using an optical fiber bundle or a multicore optical fiber, a plurality of spots are irradiated with laser light on an observation target. It may be configured to be. In addition, the following configurations may be used in combination with the configurations described in each of the modified examples described in (4. Modified Examples) as much as possible.

(6-1. Laser scanning using observation depth adjustment mechanism)
A laser scanning method using an observation depth adjustment mechanism in the laser scanning endoscope apparatus according to the present embodiment will be described with reference to FIGS. FIG. 16 is an explanatory diagram for explaining an observation depth adjustment mechanism in the laser scanning endoscope apparatus according to the present embodiment. FIG. 17 is a diagram illustrating an example of a laser scanning method using an observation depth adjustment mechanism in the laser scanning endoscope apparatus according to the present embodiment.

  Here, the laser scanning endoscope apparatus shown in FIG. 16 corresponds to the laser scanning endoscope apparatus 1 shown in FIG. 2, and is substantially the same as the laser scanning endoscope apparatus 1 already described. It has a configuration. Therefore, in the following description with reference to FIG. 16 and FIG. 17, detailed description of the configuration overlapping with the laser scanning endoscope apparatus 1 described above will be omitted, and the observation depth adjustment mechanism will be mainly described. FIG. 16 mainly illustrates a portion corresponding to the endoscope in the configuration of the laser scanning endoscope apparatus according to the present embodiment.

  Referring to FIG. 16, an endoscope 660 of the laser scanning endoscope apparatus 3 according to the present embodiment includes a collimator lens 650, a chromatic aberration correction element 670, a scanning unit 663, a rotation mechanism 667, and a lens barrel 661. A parallel movement mechanism 668 is arranged. In the example illustrated in FIG. 16, the rotation mechanism 667 and the parallel movement mechanism 668 are illustrated as integral members, but they may be disposed in the lens barrel 661 as separate members.

  An optical fiber 641 is connected to one end of the lens barrel 661 via a fiber connector 645. Laser light emitted from a laser light source (not shown) is guided into the barrel 661 by an optical fiber 641. The light guided into the lens barrel 661 by the optical fiber 641 travels in the lens barrel 661 in the longitudinal direction (y-axis direction), passes through the collimator lens 650 and the chromatic aberration correction element 670, and enters the scanning unit 663. .

  The scanning unit 663 is configured by storing an astigmatism correction element 666, an optical path changing element 664, and an objective lens 665 in a housing 669, and a rotation mechanism 667 provided at the other end of the lens barrel 661 causes a y-axis direction. Are configured to be integrally rotatable with respect to the rotation axis direction. The light incident on the scanning unit 663 passes through the astigmatism correction element 666, and its traveling direction is changed to a substantially vertical direction (the radial direction of the lens barrel 661 (z-axis direction)) by the optical path changing element 664. The light passes through the lens 665 and is guided to the outside of the housing 669. A part of the side wall of the lens barrel 661 and a portion facing the objective lens 665 is provided with a window portion 662 formed of a material that transmits at least light in a wavelength band corresponding to laser light and its return light. The light condensed by the objective lens 665 passes through the window portion 662 and is irradiated to the outside of the lens barrel 661. By bringing the window portion 662 into contact with an observation target (for example, a living tissue), the laser light is irradiated onto the observation target.

  As the scanning unit 663 rotates about the y-axis direction as a rotation axis by the rotation mechanism 667, the laser light is scanned in the x-axis direction with respect to the observation target. Further, the scanning unit 163 is translated in the y-axis direction by the translation mechanism 668, whereby the laser light is scanned in the y-axis direction with respect to the observation target. Although not shown in FIG. 16, the laser scanning endoscope apparatus 3 includes the laser light source 110, the beam splitter 120, the optical fiber light guide lens 130, the photodetector 170, and the control unit 180 shown in FIG. The configuration corresponding to the output unit 190 and the input unit 195 is provided, and an image to be observed can be acquired based on the return light by the laser scanning. Note that the optical fiber 641, the lens barrel 661, the window 662, the housing 669, the optical path changing element 664, the objective lens 665, the rotation mechanism 667, and the translation mechanism 668 shown in FIG. 16 are the same as those shown in FIG. The detailed description is omitted.

  The astigmatism correction element 666 corrects astigmatism generated when the laser light is focused on the observation target. The astigmatism correction element 666 is designed to exhibit a correction amount corresponding to the fluctuation of astigmatism accompanying the change in observation depth. Further, the chromatic aberration correcting element 670 corrects chromatic aberration caused by the difference in wavelength between the laser light and the fluorescence when detecting fluorescence emitted from the observation object as return light, for example. By providing the chromatic aberration correction element 670, it is possible to improve the light collection efficiency of the fluorescence onto the end surface of the optical fiber 641. Specific configurations of the astigmatism correction element 666 and the chromatic aberration correction element 670 will be described in detail in the following (6-2. Laser scanning probe).

  The astigmatism correction element 666 and the chromatic aberration correction element 670 correspond to the aberration correction element 166 shown in FIG. In FIG. 2, one aberration correction element 166 is shown as a representative. However, in this embodiment, as shown in FIG. 16, a plurality of aberration correction elements for correcting different types of aberrations may be provided. Good. In the example shown in FIG. 2, the aberration correction element 166 is provided between the optical path changing element 164 and the objective lens 165, but astigmatism correction element 666 and chromatic aberration correction element 670 are shown in FIG. However, even when the optical path changing element 664 is provided before the optical path changing element 664, the same aberration correction effect can be optically obtained. The astigmatism correction element 666 is required to have a relative positional relationship with the optical path changing element 164 that does not change for the purpose of correcting astigmatism. It may be arranged to rotate and / or translate with the changing element 164. On the other hand, the chromatic aberration correction element 670 can be disposed between the collimator lens 650 and the objective lens 665 so that the fluorescent light whose chromatic aberration that may occur mainly in the objective lens 165 is corrected is guided to the optical fiber 641.

  The collimator lens 650 corresponds to the optical fiber light guide lens 150 shown in FIG. The collimator lens 650 converts the emitted light from the optical fiber 641 into substantially parallel light and guides it to a subsequent member. Further, by moving the collimator lens 650 in the optical axis direction (y-axis direction), the focusing state and the diverging state of the laser light in the objective lens 665 can be changed, and the observation depth can be changed.

  The laser scanning endoscope apparatus 3 may be further provided with a moving mechanism (not shown) for moving the collimator lens 650 in the y-axis direction. An observation depth adjusting mechanism is provided by the collimator lens 650 and the moving mechanism. Can be configured. By changing the observation depth by the observation depth adjustment mechanism, it is possible to scan the laser beam also in the depth direction (z-axis direction) of the observation target. Accordingly, the movement of the collimator lens 650 is controlled in synchronization with the rotation and parallel movement of the scanning unit 663, so that three-dimensional laser scanning can be performed on the observation target. The specific configuration of the moving mechanism that moves the collimator lens 650 may be the same as that of the parallel moving mechanism 668. For example, the moving mechanism can be configured by a linear actuator, a piezoelectric element, or the like.

  Here, when the observation depth adjustment mechanism is provided, the rotation of the scanning unit 663 (that is, laser scanning in the x-axis direction) and the change of the observation depth (that is, laser scanning in the z-axis direction) are coordinated. Thus, it becomes possible to perform more accurate observation. With reference to FIG. 17, a laser scanning method for controlling the rotation of the scanning unit 663 and the change of the observation depth in a coordinated manner will be described.

  FIG. 17 illustrates a state in which the window 662 is in contact with the living tissue 500 that is the observation target when the endoscope 660 is viewed from the y-axis direction. In FIG. 17, the illustration of the lens barrel 661, the scanning unit 663, and the like is omitted, and the scanning trajectories (scanning trajectories) R1 and R2 of the laser light accompanying the rotation of the scanning unit 663 are schematically represented by circles. As shown in FIG. 17, the scan trajectories R1 and R2 at different observation depths can be expressed as two circles having different radii.

  In the laser scanning endoscope apparatus 3, laser scanning in the x-axis direction is performed by the rotation of the scanning unit 663. Therefore, the scanning of the laser beam in the x-axis direction with respect to the living tissue 500 may actually be a laser scanning along an arc as shown in FIG. 17 instead of a linear scanning along the x-axis direction. In this state, when the scanning unit 663 is translated and laser scanning is performed in the y-axis direction, a cross-sectional image along the arc is obtained. However, depending on the object to be observed and the purpose of observation, it may be possible to observe a cross section substantially parallel to the x-axis direction.

  In response to such a demand, in the present embodiment, the observation depth is dynamically changed during one rotation of the scanning unit 663 using the observation depth adjustment mechanism, so that a straight line along the x-axis direction is obtained. Laser beam scanning can be realized. Specifically, as shown in FIG. 17, in synchronization with the rotation of the scanning unit 663, by continuously changing the scan trajectory from the scan trajectory R1 to the scan trajectory R2, and further from the scan trajectory R2 to the scan trajectory R1, The driving of the observation depth adjustment mechanism is controlled so that the observation depth in the living tissue 500 is substantially parallel to the x axis. By performing such control, it becomes possible to perform laser scanning in the x-axis direction at a substantially constant observation depth. Therefore, combining with laser scanning in the y-axis direction by parallel movement of the scanning unit 663 is combined. Thus, it is possible to observe a planar cross section in the living tissue 500.

  The laser scanning method using the observation depth adjustment mechanism in the laser scanning endoscope apparatus 3 according to this embodiment has been described above with reference to FIGS. 16 and 17. In the present embodiment, the observation depth adjustment mechanism is used to coordinately control the rotation of the scanning unit 663 and the change of the observation depth, so that the living tissue 500 is linear at a substantially constant observation depth. It is possible to perform laser scanning. Thereby, since it becomes possible to observe the planar cross section of observation object according to a user's request, a user's convenience can be improved more. Further, the laser scanning endoscope apparatus 3 includes an astigmatism correction element 666 that corrects the astigmatism with a correction amount corresponding to a change in astigmatism accompanying a change in observation depth. Therefore, even when the observation depth is changed, high-precision observation can be performed.

(6-2. Laser scanning probe)
The laser scanning endoscope apparatus 3 described above is provided with a scanning unit 663 that is rotatable inside the barrel 661 of the endoscope 660 with the longitudinal direction of the barrel 661 as the rotation axis direction. The observation target is irradiated with laser light through a window portion 662 provided on the side wall of 661. However, in this embodiment, more generally, the scanning unit 663 and other optical members are arranged inside a cylindrical housing, and a window portion is provided in at least a partial region of the side wall of the housing. A laser scanning probe may be configured. The portion corresponding to the endoscope 660 of the laser scanning endoscope apparatus 3 described above is an application example of the laser scanning probe, and the laser scanning probe is directly or directly connected to an existing endoscope. It can be considered that it was stored in the tip of the lens barrel and inserted into the body cavity of the measurement subject. Further, when the laser scanning probe is applied to the laser scanning endoscope apparatus as described above, for example, the diameter of the cylindrical housing is required to be approximately 10 (mm) or less. In the embodiment, the laser scanning probe is configured to be larger (for example, the housing has a diameter of more than about 10 (mm)), and is brought into contact with the body surface of a human or animal to be observed to have a predetermined depth from the body surface. It may be used for the purpose of observing a living tissue.

  Here, a configuration example of such a laser scanning probe according to the present embodiment will be described. Hereinafter, as an example of the laser scanning probe according to the present embodiment, a configuration of a laser scanning probe that suitably performs observation using two-photon excitation will be described. By using two-photon excitation, it is possible to acquire not only the surface of the observation target but also information in the depth direction. In addition, since information of an observation target can be obtained by detecting fluorescence emitted by irradiating excitation light (laser light), other scattering and absorption such as OCT, photoacoustic, and confocal reflection are visualized. It is possible to obtain more detailed molecular-level knowledge about the observation object that cannot be obtained by optical imaging technology. Further, by using near-infrared light as excitation light, it is possible to reduce damage to a human being, for example, an observation target.

(6-2-1. Configuration of Laser Scanning Probe)
The configuration of the laser scanning probe according to the present embodiment will be described with reference to FIGS. FIG. 18 is a side view showing a configuration example of the laser scanning probe according to the present embodiment. In FIG. 18, constituent members that pass through the casing that constitutes the laser scanning probe and are arranged inside the casing are illustrated. 19 to 21 are diagrams showing the arrangement of optical members in the laser scanning probe shown in FIG.

  Referring to FIG. 18, in the laser scanning probe 4 according to the present embodiment, a collimator lens 720, a chromatic aberration correction element 740, a scanning unit 733, a rotation mechanism 737, and a parallel movement mechanism 738 are arranged in a cylindrical housing 731. Configured. Note that the laser scanning probe 4 shown in FIG. 18 has substantially the same configuration as the endoscope 660 shown in FIG. 16 if the casing 731 is regarded as a barrel of the endoscope. Therefore, in the following description with reference to FIG. 18, detailed description of the same configuration as that of the above-described laser scanning endoscope apparatus 3 is omitted.

  An optical fiber 710 is connected to one end of the housing 731 via a fiber connector 765. Laser light emitted from a laser light source (not shown) is guided into the housing 731 by the optical fiber 710. The light guided into the housing 731 by the optical fiber 710 travels in the housing 731 in the longitudinal direction (y-axis direction), passes through the collimator lens 720 and the chromatic aberration correction element 740, and enters the scanning unit 733. .

  The scanning unit 733 is configured by storing an astigmatism correction element 736, an optical path changing element 734, and an objective lens 735 in a housing 739, and a y-axis direction by a rotation mechanism 737 provided at the other end of the housing 731. Are configured to be integrally rotatable with respect to the rotation axis direction. The light incident on the scanning unit 733 passes through the astigmatism correction element 736, and the traveling direction thereof is changed to a substantially vertical direction (the radial direction of the housing 731 (z-axis direction)) by the optical path changing element 734. The light passes through the lens 735 and the spherical aberration correction element 745 and is guided to the outside of the housing 739. A window portion 732 formed of a material that transmits at least laser light and light in a wavelength band corresponding to the return light is formed in a part of the side wall of the housing 731 and facing the objective lens 735. The light collected by the objective lens 735 passes through the window portion 732 and is irradiated to the outside of the housing 731. By bringing the window unit 732 into contact with the observation target (for example, the living tissue 500), the laser light is irradiated onto the observation target.

  When the scanning unit 733 is rotated about the y-axis direction as a rotation axis by the rotation mechanism 737, the laser light is scanned in the x-axis direction with respect to the observation target. Further, when the scanning unit 733 is translated in the y-axis direction by the parallel movement mechanism 738, the laser light is scanned in the y-axis direction with respect to the observation target. Although not shown in FIG. 18, the laser scanning probe 4 includes the laser light source 110, the beam splitter 120, the optical fiber light guiding lens 130, the photodetector 170, the control unit 180, and the output unit shown in FIG. A configuration corresponding to 190 and the input unit 195 is provided, and an image of the living tissue 500 can be acquired based on return light by laser scanning. In the example illustrated in FIG. 18, the rotation mechanism 737 and the parallel movement mechanism 738 are illustrated as integral members, but they may be disposed in the housing 731 as separate members. Further, the optical fiber 710, the window portion 732, the housing 739, the optical path changing element 734, the objective lens 735, the rotation mechanism 737, and the parallel movement mechanism 738 shown in FIG. 18 have the same functions as those components shown in FIG. Since it may be a thing, detailed description is abbreviate | omitted.

  Here, the collimator lens 720 corresponds to the collimator lens 650 shown in FIG. In the laser scanning probe 4 as well, the collimator lens 720 is moved in the y-axis direction in the same manner as the laser scanning endoscope apparatus 3 described in (6-1. Laser scanning using observation depth adjusting mechanism). A moving mechanism (not shown) may be further provided, and the observation depth may be changed by moving the collimator lens 720 in the y-axis direction by the moving mechanism.

  The astigmatism correction element 736 and the chromatic aberration correction element 740 correspond to the astigmatism correction element 666 and the chromatic aberration correction element 670 shown in FIG. The astigmatism correction element 736 is designed to cope with fluctuations in astigmatism accompanying changes in the observation depth. Further, the chromatic aberration correcting element 740 corrects the condensing efficiency of the fluorescence onto the optical fiber 710 by correcting the chromatic aberration caused by the difference in wavelength between the laser light and the fluorescence that is the return light, for example, in observation using two-photon excitation. To improve.

  The spherical aberration correction element 745 is provided to correct spherical aberration that may be caused by the objective lens 735. In the example shown in FIG. 18, the spherical aberration correction element 745 is a parallel plate, but the specific configuration of the spherical aberration correction element 745 is not limited to this example. Parameters that can determine the optical characteristics such as the shape and material of the spherical aberration correction element 745 may be appropriately designed according to the optical characteristics of the objective lens 735 so that the spherical aberration can be corrected. When the objective lens 735 is an aspheric lens, the objective lens 735 itself may be provided with a spherical aberration correction function, and the spherical aberration correction element 745 may not be provided.

  In response to performing observation using two-photon excitation, a double-clad optical fiber is preferably used as the optical fiber 710. When the optical fiber 710 is a double-clad optical fiber, for example, a laser beam (that is, excitation light) is guided to the inside of the housing 731 by the core, and fluorescence that is return light from the living tissue 500 is transmitted by the inner cladding. Since the light can be guided to the outside of the housing 731, the light collection efficiency of the fluorescence to the optical fiber 710 can be improved.

  The housing 731 may be formed with the window portion 732 only in a region having a predetermined length in the y-axis direction, or the entire housing 731 may be formed of the same material as the window portion 732. . For example, the housing 731 may be a glass tube formed of a material transparent to at least a wavelength band corresponding to laser light and fluorescence.

  Here, the arrangement of the optical members in the laser scanning probe 4 will be described with reference to FIGS. FIG. 19 shows a state in which the constituent members inside the housing 631 shown in FIG. 18 are observed from the positive direction (upward) of the z-axis. FIG. 20 shows a state in which the constituent members inside the casing 631 shown in FIG. 18 are observed from the x-axis direction (side). FIG. 21 is a cross-sectional view on the xz plane including the optical axis of the objective lens 735 in the configuration shown in FIG. In FIGS. 19 to 21, the housing 731, the housing 739 of the scanning unit 733, and the like are partially illustrated so as to show the arrangement of each optical member. Moreover, in FIGS. 19-21, in order to show an example of the path | route of the light which passes each optical member, the straight line showing light is also shown in figure.

  Referring to FIG. 19 to FIG. 21, the light emitted from the optical fiber 710 passes through the collimator lens 720, the chromatic aberration correction element 740, and the astigmatism correction element 736, and its traveling direction is changed by the optical path changing element 734. A state in which the light passes through the objective lens 735 and the window portion 732 and is irradiated to the outside is illustrated. The astigmatism correction element 736, the optical path changing element 734, and the objective lens 735 are housed in the housing 739, and are rotated integrally by the rotation mechanism 737 with the y-axis direction as the rotation axis direction.

  As the astigmatism correction element 736, for example, a cylindrical meniscus lens (for example, corresponding to the cylindrical meniscus lens 630 shown in FIG. 14 described above) in which a convex lens is formed on one surface and a concave lens is formed on the other surface is used. Further, as the astigmatism correction element 736, for example, a configuration in which two cylindrical lenses are combined, such as the cylindrical concave / convex lens pair 620 shown in FIGS. 13A and 13B described above, may be used. On the other hand, as the chromatic aberration correcting element 740, for example, a cemented lens in which two concave lenses are cemented with the lens surfaces facing each other is used. In FIG. 19 to FIG. 21, the chromatic aberration correction element 740 and the astigmatism correction element 736 are schematically shown by omitting their detailed shapes for simplicity. Here, in this embodiment, astigmatism is produced according to the optical characteristics of other optical members (for example, a collimator lens 720, an optical path changing element 734, an objective lens 735, a spherical aberration correction element 745, and / or a window portion 732). High-quality observation images can be obtained by optical design of the optical system so that the correction element 736 and the chromatic aberration correction element 740 have predetermined optical characteristics. In the following (6-2-2. Astigmatism correction element) and in the following (6-2-3. Chromatic aberration correction element), the astigmatism correction element 736 and the chromatic aberration correction element 740 will be described in detail.

(6-2-2. Astigmatism correction element)
First, with reference to FIG. 22, parameters affecting astigmatism in the optical system of the laser scanning probe 4 will be described. FIG. 22 is an explanatory diagram for explaining parameters affecting astigmatism in the optical system of the laser scanning probe 4. In FIG. 22, only the optical fiber 710, the collimator lens 720, the astigmatism correction element 736, the objective lens 735, and the window portion 732 are illustrated in the configuration of the laser scanning probe 4 illustrated in FIGS. Show. In actuality, as shown in FIGS. 18 to 21, the light whose traveling direction is changed by the optical path changing element 734 enters the objective lens 735, but the optical path changing element 734 is not shown in FIG. 22. The change of the traveling direction of the laser beam is represented by a broken line.

  As described above (5-1. Correction of Astigmatism), as a result of the study by the present inventors, the degree of astigmatism is determined by the optical distance in the observation depth direction (the refractive index of the medium and the observation depth). The knowledge that it changes according to the product of the distance in the vertical direction) was obtained. That is, the astigmatism generated when the convergent light from the objective lens 735 passes through the window portion 732 depends on the thickness of the window portion 732, the distance between the objective lens 735 and the window portion 732, and the observation depth. I can say that. Here, as shown in FIG. 22, in the laser scanning probe 4 according to the present embodiment, the observation depth can be changed by changing the position of the collimator lens 720 in the optical axis direction. Accordingly, the astigmatism correction element 736 is required to have an optical characteristic that realizes a correction amount corresponding to a change in the degree of astigmatism accompanying a change in observation depth.

  In order to realize such optical characteristics in the astigmatism correction element 736, the astigmatism dependency in the window portion 732 is obtained for each observation depth by obtaining the astigmatism dependency of the astigmatism in the window portion 732. The shape and material of the astigmatism correction element 736 may be designed so as to have a reverse astigmatism characteristic that just cancels out. In such an astigmatism correction element 736 capable of canceling astigmatism in the window portion 732 even if the observation depth changes, for example, the laser light passes through at least two cylindrical surfaces or toroidal surfaces. It can be realized by a lens configured as described above. For example, as the astigmatism correction element 736, a cylindrical meniscus lens having both surfaces concave with respect to the light incident from the optical fiber 710 (that is, the curved surface has the same direction of curvature) as shown in FIG. It can be suitably applied.

  FIG. 23 shows an example of optical characteristics of a cylindrical meniscus lens used as the astigmatism correction element 736 in this embodiment. FIG. 23 is a graph showing an example of the optical characteristics of a cylindrical meniscus lens used as the astigmatism correction element 736 in the present embodiment. In FIG. 23, the horizontal axis represents the observation depth, and the vertical axis represents the fringe Zernike polynomial coefficient that is an index indicating the degree of astigmatism, and the relationship between the two is plotted.

  A curve G shown in FIG. 23 shows the observation depth dependency of astigmatism in the window portion 732. A curve H indicates the observation depth dependency of astigmatism in a cylindrical meniscus lens used as the astigmatism correction element 736. A curve I represents astigmatism characteristics that can be realized in the present embodiment, in which the astigmatism of the window portion 732 and the astigmatism of the cylindrical meniscus lens are added. Comparing the curve G and the curve H, the astigmatism characteristic of the cylindrical meniscus lens has almost the opposite characteristic to the observation depth dependency of the astigmatism in the window portion 732, and is shown by the curve I. Thus, it can be seen that the astigmatism is almost canceled by adding the two together.

  Here, referring to FIG. 24, when astigmatism is corrected by an optical member having two curved surfaces (cylindrical surface or toroidal surface), and astigmatism is corrected by an optical member having one curved surface. Compare with the case. The optical member having two curved surfaces corresponds to, for example, the above-described cylindrical meniscus lens. An optical member having one curved surface is generally used to correct astigmatism, such as a plano-convex cylindrical lens or a mirror used as an optical path changing element having a concave cylindrical curved surface formed on the surface. It corresponds to the optical member used.

  FIG. 24 is a graph showing the dependence of astigmatism on the observation depth of an optical member having two curved surfaces and an optical member having one curved surface. In FIG. 24, the horizontal axis represents the observation depth, the vertical axis represents the RMS wavefront aberration, which is an index indicating the degree of wavefront aberration, and the relationship between the two is plotted.

  A curve J shown in FIG. 24 shows the observation depth dependence of the wavefront aberration of an optical member having one curved surface. A curve K shown in FIG. 24 shows the observation depth dependency of the wavefront aberration of an optical member having two curved surfaces. As shown in FIG. 24, the optical member having only one surface has a large variation in the degree of aberration with respect to the observation depth. Therefore, when an optical member having only one surface is used as the astigmatism correction element 736, it is possible to perform optical design so as to correct astigmatism at a specific observation depth. It is difficult to handle even when the observation depth changes. On the other hand, in the optical member having two curved surfaces, the variation in the degree of aberration with respect to the observation depth is relatively small. Therefore, by using an optical member having curved surfaces on two surfaces as the aberration correction element, it is possible to correct aberrations at a substantially constant rate even when the observation depth changes. Thus, for example, by using a lens having two curved surfaces as the astigmatism correction element 736 such as the above-described cylindrical meniscus lens, astigmatism correction corresponding to a change in observation depth can be performed. .

  Note that the specific shape (for example, the curvatures of both curved surfaces) of the cylindrical meniscus lens used as the astigmatism correction element 736 is astigmatism generated when the laser light as described above is condensed on the observation target. (For example, the thickness of the window portion 732, the distance between the objective lens 735 and the window portion 732, the material of the objective lens 735 and the window portion 732, and the shape of the objective lens 735 and the window portion 732 ( Depending on the curvature, etc.)), it may be designed as appropriate using, for example, an optical simulator.

  The configuration of the astigmatism correction element 736 according to this embodiment has been described above in detail. As described above, in the present embodiment, as the astigmatism correction element 736, an optical member having an optical characteristic that realizes a correction amount corresponding to a change in astigmatism accompanying a change in observation depth is used. . Such optical characteristics can be realized by a lens system configured to allow laser light to pass through at least two cylindrical surfaces or toroidal surfaces. Accordingly, the astigmatism correction element 736 may be realized by a single lens such as the above-described cylindrical meniscus lens, or at least 2 such as the cylindrical concave / convex lens pair 620 shown in FIGS. 13A and 13B. It may be realized by a lens system having a cylindrical surface or a toroidal surface. By using such an astigmatism correction element 736, when performing observation while changing the observation depth, that is, when performing laser scanning in the depth direction, the influence of astigmatism is less and more accurate. Observation can be performed.

  Here, the case where the astigmatism correction element 736 includes a lens configured to allow laser light to pass through at least two cylindrical surfaces or toroidal surfaces has been described above. However, the present embodiment is limited to this example. Not. For example, even an optical member having a curved surface on one surface is provided with a drive mechanism that changes the shape of the curved surface in accordance with the change in observation depth, thereby astigmatism in accordance with the change in observation depth. As a result, the astigmatism correction characteristic similar to that of the cylindrical meniscus lens described above can be realized. As described above, the astigmatism correction element 736 includes an optical member (hereinafter also referred to as an active astigmatism correction element) including a drive element that dynamically changes the correction amount of astigmatism according to a change in observation depth. .) As the active astigmatism correction element, for example, a liquid crystal element, a liquid lens, a deformable mirror, or the like can be used.

  Here, when an optical member whose optical characteristics do not change dynamically, such as the above-described cylindrical meniscus lens, is used as the astigmatism correction element 736, the astigmatism correction element 736 is used when performing laser scanning. And the optical path changing element 734 must be rotated together. This is because if the relative positional relationship between the astigmatism correction element 736 and the optical path changing element 734 changes, a desired astigmatism correction characteristic may not be realized. On the other hand, when an active astigmatism correction element is used as the astigmatism correction element 736, the astigmatism correction element 736 does not have to rotate with the optical path changing element 734. Since the astigmatism correction element 736 can dynamically change the correction amount of the astigmatism, the correction of astigmatism is performed according to both the change in observation depth and the rotation of the optical path changing element 734. This is because the amount can be changed. As described above, by using the active astigmatism correction element as the astigmatism correction element 736, it is possible to reduce the number of structural members that are rotated as the scanning unit 733, and thus the output and rigidity required for the rotation mechanism 737 can be reduced. The rotation mechanism 737 can be designed more easily.

(6-2-3. Chromatic aberration correction element)
With reference to FIG. 25, the chromatic aberration correction element 740 applied to the laser scanning probe 4 will be described. FIG. 25 is an explanatory diagram for explaining a chromatic aberration correction element 740 applied to the laser scanning probe 4. In FIG. 25, only the optical fiber 710, the collimator lens 720, the chromatic aberration correction element 740, and the objective lens 735 are simplified in the configuration of the laser scanning probe 4 shown in FIGS. .

  As described above, in the laser scanning probe 4 according to this embodiment, observation using two-photon excitation is preferably performed. In observation using two-photon excitation, laser light, which is excitation light, is emitted from the optical fiber 710, and sequentially passes through the collimator lens 720, the chromatic aberration correction element 740, and the objective lens 735, and is irradiated to the living tissue 500 (in the drawing). (A)). Further, the fluorescence emitted from the living tissue 500 by the irradiation of the laser light follows a path opposite to that of the laser light, and sequentially passes through the objective lens 735, the chromatic aberration correction element 740, and the collimator lens 720, and is guided to the optical fiber 710. For example, it is detected by a photodetector (not shown) provided outside ((b) in the figure). Therefore, in order to perform observation more efficiently, it is necessary to improve the light collection efficiency of the fluorescence to the optical fiber 710.

  Here, the wavelength of the laser light applied to the living tissue 500 and the fluorescence returning from the living tissue 500 as return light often have different wavelengths. For example, when laser light having a wavelength (785 (nm)) corresponding to near-infrared light is used, fluorescence that is the return light may be light in the visible light band. Therefore, when the fluorescence returned from the living tissue 500 passes through the objective lens 735, chromatic aberration is generated, and the light collection efficiency of the fluorescence onto the core of the optical fiber 710 may be lowered. Therefore, in this embodiment, as shown in FIG. 25, a double clad optical fiber is used as the optical fiber 710, and laser light propagates in the single mode through the core of the optical fiber 710, while fluorescence propagates through the inner clad to detect light. Guide light to the vessel. By adopting such a configuration, it is only necessary to condense the fluorescence onto the portion of the inner clad having a larger area at the end of the optical fiber 710, so that the light collection efficiency can be improved.

  However, when the degree of chromatic aberration is large, there is a possibility that sufficient fluorescence condensing efficiency cannot be obtained even if a double clad optical fiber is used. Therefore, in the present embodiment, as shown in FIG. 25, a chromatic aberration correction element 740 is provided between the collimator lens 720 and the objective lens 735. By providing the chromatic aberration correction element 740, chromatic aberration caused by the fluorescence passing through the objective lens 735 is corrected, and the light collection efficiency of the fluorescence onto the optical fiber 710 can be further improved. The chromatic aberration correcting element 740 functions as a substantially parallel plate for laser light having a wavelength (785 (nm)) corresponding to near-infrared light, for example, but has a wavelength band (for example, visible light band) corresponding to fluorescence. For this light, a cemented lens having an optical characteristic that functions as a concave lens is preferably used.

  FIG. 26 shows the condensing efficiency of fluorescence onto the optical fiber 710 when the chromatic aberration correction element 740 is applied and when it is not applied. FIG. 26 is a graph showing the light collection efficiency of the fluorescence onto the optical fiber 710 when the chromatic aberration correction element 740 is applied and when it is not applied. In FIG. 26, the horizontal axis represents the fluorescence wavelength, the vertical axis represents the light collection efficiency of the fluorescence onto the optical fiber 710, and the relationship between the two is plotted.

  A curve L shown in FIG. 26 indicates the fluorescence condensing efficiency when the chromatic aberration correction element 740 is not applied. A curve M indicates the fluorescence condensing efficiency when the chromatic aberration correcting element 740 is applied. Referring to FIG. 26, as indicated by the curve L, it can be seen that when the chromatic aberration correction element 740 is not applied, the light collection efficiency for fluorescence having a short wavelength is significantly reduced. This is presumably because the shorter the fluorescence wavelength, the greater the difference in wavelength with the laser light and the greater the degree of chromatic aberration, making it difficult for the fluorescence to be collected at the end of the optical fiber 710. On the other hand, as indicated by the curve M, when the chromatic aberration correction element 740 is applied, high light collection efficiency is ensured regardless of the wavelength of fluorescence. As described above, in the present embodiment, by arranging the chromatic aberration correction element 740, it is possible to improve the light collection efficiency of the fluorescence onto the optical fiber 710, and it is possible to perform observation more efficiently.

  The chromatic aberration correction element 740 according to this embodiment has been described above. Note that the specific configuration such as the shape and material of the chromatic aberration correction element 740 is determined by considering the optical characteristics of the objective lens 735, the wavelength of the laser beam used for observation, the wavelength of the fluorescence to be detected, and the like. It is possible to design appropriately so that the light collection efficiency to the optical fiber 710 can be obtained.

(6-2-4. Other Configuration Examples of Laser Scanning Probe)
Next, another configuration example of the laser scanning probe according to this embodiment will be described. As described above, in the present embodiment, the laser scanning probe is configured to be larger, for example, while the user grips the probe with a hand, the window portion is brought into contact with the body surface of a human or animal to be observed, and the body Laser scanning may be performed on a living tissue at a predetermined depth from the surface.

  With reference to FIG. 27, the configuration of such a hand-held laser scanning probe will be described as another configuration example of the laser scanning probe according to the present embodiment. FIG. 27 is a perspective view showing a configuration of a hand-held laser scanning probe as another configuration example of the laser scanning probe according to the present embodiment. In FIG. 27, in order to show the components arranged inside the housing, the housing is shown in a transparent manner.

  Referring to FIG. 27, the laser scanning probe 5 according to the present embodiment is configured by arranging a collimator lens 770, a chromatic aberration correction element 790, and a scanning unit 783 in a substantially rectangular parallelepiped casing 781. Thus, in this embodiment, the shape of the housing 781 of the laser scanning probe 5 may not be cylindrical. As the shape of the housing 781, for example, in consideration of operability by the user, a shape that is easier for the user to hold can be selected. The laser scanning probe 5 shown in FIG. 27 may have substantially the same optical configuration as that of the laser scanning probe 4 shown in FIG. 18 except that the shape of the housing 781 is different. Therefore, in the description with reference to FIG. 27 below, detailed description of the configuration overlapping with the laser scanning probe 4 described above is omitted.

  An optical fiber 760 is connected to one end of the housing 781 via a fiber connector 765. Laser light emitted from a laser light source (not shown) is guided into the housing 781 by the optical fiber 760, passes through the collimator lens 770 and the chromatic aberration correction element 790, and enters the scanning unit 783.

  The scanning unit 783 includes an astigmatism correction element 786, an optical path changing element 784, and an objective lens 785 housed in a housing 789, and is rotated in the y-axis direction by a rotation mechanism 787 provided at the other end of the housing 781. It is configured to be integrally rotatable as an axial direction. The light incident on the scanning unit 733 passes through the astigmatism correction element 786, and the traveling direction of the light is changed by the optical path changing element 784 in a substantially vertical direction (for example, a surface direction having a curvature of the housing 731 (z-axis direction in the drawing) ) And is guided to the outside of the housing 789 through the objective lens 785.

  A cylindrical glass tube 782 is disposed inside the housing 781 so as to surround the scanning unit 783. Further, at least one surface of the housing 781 is formed to have a curvature corresponding to the glass tube 782. An opening is provided in a partial region of the curved surface of the housing 781 so that a part of the glass tube 782 is exposed in the opening (that is, a part of the glass tube 782 is the housing). The casing 781 and the glass tube 782 are configured so as to constitute part of a surface having a curvature of 781). The laser light condensed by the objective lens 785 and emitted from the scanning unit 783 passes through an exposed portion of the glass tube 782 (hereinafter also referred to as a window portion 782) and is irradiated to the outside of the housing 781. . By bringing the exposed portion of the glass tube 782 into contact with the observation target, the laser light is irradiated onto the observation target. Thus, the exposed portion of the glass tube 782 corresponds to the window portion 732 of the laser scanning probe 4 shown in FIG.

  The scanning unit 783 is rotated about the y-axis direction as a rotation axis by the rotation mechanism 787, whereby the laser light is scanned in the x-axis direction with respect to the observation target. Further, the translation unit 788 causes the scanning unit 783 to translate in the y-axis direction, whereby the laser light is scanned in the y-axis direction with respect to the observation target. Although not shown in FIG. 27, the laser scanning probe 5 includes the laser light source 110, the beam splitter 120, the optical fiber light guide lens 130, the photodetector 170, the control unit 180, and the output unit shown in FIG. A configuration corresponding to 190 and the input unit 195 is provided, and an image to be observed can be acquired based on return light by laser scanning. In the example shown in FIG. 27, the rotation mechanism 787 and the parallel movement mechanism 788 are illustrated as integral members, but they may be disposed in the housing 781 as separate members. In addition, the optical characteristics of optical elements such as the collimator lens 770, the optical path changing element 784, the objective lens 785, the astigmatism correction element 786 and the chromatic aberration correction element 790 shown in FIG. 27, and the driving mechanism of the rotation mechanism 787 and the parallel movement mechanism 788 are shown. Since the detailed configuration may have the same functions as those of these components shown in FIG. 18, detailed description thereof will be omitted.

  Similarly to the laser scanning probe 4 shown in FIG. 18, the laser scanning probe 5 may be further provided with a moving mechanism (not shown) for moving the collimator lens 770 in the y-axis direction. The observation depth may be changed by moving the collimator lens 770 in the y-axis direction by a mechanism. As a result, laser scanning in the z-axis direction can be performed, and three-dimensional image data can be acquired together with the laser scanning in the x-axis and y-axis directions described above.

  The laser scanning probe 5 shown in FIG. 27 is suitably used for observing a place that can be contacted from the outside, such as human skin or oral cavity. For example, the laser scanning probe 5 is equipped with a camera device (not shown) that images the outside from a window portion 782 where laser scanning is performed. While the window portion 782 of the laser scanning probe 5 is in contact with the observation target, the user moves the laser scanning probe 5 while referring to an image photographed by the camera device, and searches for a part to be observed in detail. can do. When a desired observation site is found, laser scanning for the site is started. In this way, the laser scanning probe 5 can be moved relatively freely by the user's hand, so that observation with higher operability can be performed.

  As another method of using the laser scanning probe 5, the laser scanning probe 5 is attached to one part of the body of a test animal (for example, the head or torso) and the state of the brain or organ is observed over time. It is also possible to use it. In the case of such a usage method, the laser scanning probe 5 is preferably configured to be relatively small and light so as not to give an excessive burden to the animal.

  The other configuration examples of the laser scanning probe according to the present embodiment have been described above. As described above, the laser scanning observation apparatus according to the present embodiment may be the hand-held laser scanning probe 5 that is assumed to be used by the user. As described above, in this embodiment, the laser scanning observation apparatus observes not only a living tissue in a body cavity like an endoscope but also a living tissue located at a predetermined depth from the body surface. It can also be used for applications.

(6-3. Laser scanning microscope)
Next, a configuration example of the laser scanning microscope apparatus according to the present embodiment will be described with reference to FIG. FIG. 28 is a schematic diagram illustrating a configuration example of the laser scanning microscope apparatus according to the present embodiment. In FIG. 28, the casing is not shown in order to show the components disposed inside the casing.

  Referring to FIG. 28, the laser scanning microscope apparatus 6 according to the present embodiment includes a laser light source 810, a beam splitter 820, a photodetector 870, a collimator lens 850, a chromatic aberration correction element 840, a scanning unit 863, a rotation mechanism 867, and a parallel. A moving mechanism 868 is arranged in a housing (not shown). As described above, since the optical system from the laser light source to the scanning unit can be provided in one casing, the laser scanning microscope apparatus 6 does not need to use a light guide member such as an optical fiber. The laser scanning microscope apparatus 6 shown in FIG. 28 is provided with a laser light source 810, a beam splitter 820, and a photodetector 870 in a casing, and has a configuration other than that an optical fiber is not used, particularly its optical configuration. May be substantially the same as the laser scanning probe 4 shown in FIG. Therefore, in the following description with reference to FIG. 28, the detailed description of the same configuration as the laser scanning probe 4 described above is omitted.

  Laser light emitted from the laser light source 810 passes through the collimator lens 850 and the chromatic aberration correction element 840 and enters the scanning unit 863. The scanning unit 863 is configured by housing an astigmatism correction element 866, an optical path changing element 864, and an objective lens 865 in a housing 869. For example, a rotation mechanism 867 and a parallel movement mechanism 868 configured by a motor or a linear actuator are connected to the scanning unit 863, and the scanning unit 863 can rotate integrally with the y-axis direction as the rotation axis direction. , And can be moved in parallel in the y-axis direction. The light incident on the scanning unit 863 passes through the astigmatism correction element 866, the traveling direction thereof is changed to a substantially vertical direction (z-axis direction in the drawing) by the optical path changing element 864, and the light passes through the objective lens 865. The light is guided outside the housing 869.

  Here, the laser scanning microscope apparatus 6 is provided with a stage 880 on which the observation target 500 is placed, and the scanning unit 863 has a back surface of the placement surface of the observation target 500 of the stage 880. It is arrange | positioned in the position facing. A window portion 862 is formed of a material that transmits light in a wavelength band corresponding to at least a laser beam at least in a region facing the scanning portion 863 of the stage 880, and is condensed by the objective lens 865, and is scanned. The laser light emitted from the laser beam irradiates the observation object 500 placed on the stage 880 through the window portion 862. As shown in FIG. 28, a preparation in which the observation object 500 is placed on a sample placement member such as the slide glass 510 may be prepared in advance, and the preparation may be placed on the stage 880. . In this case, since the laser light passes through the slide glass 510 and is irradiated onto the observation object 500, the slide glass 510 is preferably formed of a material having optical characteristics that do not hinder laser scanning. Can be used.

  The scanning unit 863 is rotated by the rotation mechanism 867 with the y-axis direction as the rotation axis direction, whereby the laser light is scanned in the x-axis direction with respect to the observation target 500. Further, the scanning unit 863 is translated in the y-axis direction by the translation mechanism 868, so that the laser light is scanned in the y-axis direction with respect to the observation object 500. The return light from the observation object 500 traces the path through which the laser light has passed, that is, passes through the objective lens 865, the optical path changing element 864, the astigmatism correction element 866, the chromatic aberration correction element 840, and the collimator lens 850. Then, the light is guided toward the photodetector 870 by the beam splitter 820. In accordance with the return light detected by the photodetector 870, information about the observation target 500 is acquired as image data, for example.

  Further, the laser scanning microscope apparatus 6 may be further provided with a moving mechanism (not shown) for moving the collimator lens 850 in the y-axis direction, similarly to the laser scanning probe 4 shown in FIG. The observation depth may be changed by moving the collimator lens 850 in the y-axis direction by the moving mechanism. This makes it possible to perform laser scanning in the depth direction (z-axis direction) with respect to the observation target 500, and acquire three-dimensional image data in combination with the above-described laser scanning in the x-axis and y-axis directions. be able to.

  28, the laser light source 810, the beam splitter 820, the photodetector 870, the collimator lens 850, the optical path changing element 864, the objective lens 865, the astigmatism correction element 866, the chromatic aberration correction element 840, the rotation mechanism 867, and the parallel movement. Since the configuration of the mechanism 868 and the like may have the same function as those of the components shown in FIGS. 2 and 18, detailed description thereof will be omitted. Although not shown in FIG. 28, the laser scanning microscope apparatus 6 may further include a configuration corresponding to the control unit 180, the output unit 190, and the input unit 195 shown in FIG. With this configuration, an image of the observation object 500 can be acquired based on the return light from the laser scanning.

  The configuration example of the laser scanning microscope apparatus according to this embodiment has been described above. As described above, the laser scanning observation apparatus according to the present embodiment may be the laser scanning microscope apparatus 6. Here, in the laser scanning endoscope apparatus 3 shown in FIG. 16 and the laser scanning probe 5 shown in FIG. 27, the living tissue in the body cavity of the measurement subject is observed, or the user scans the laser scanning probe. 5 is assumed to be held and used by hand, the optical system such as the scanning unit and the drive system such as the rotation mechanism and the parallel movement mechanism need to be relatively small. On the other hand, in the laser scanning microscope apparatus 6, the observation target is placed on a stage provided in the apparatus, and laser scanning is performed on the observation target on the stage. The demand for downsizing is relatively relaxed. Therefore, the optical system and the drive system can be designed with a higher degree of freedom.

  Here, the above-described rotation mechanism 867 will be examined as an example of the drive system. As described in the above (2. First Embodiment), for example, if the image data of one frame is (x × y) = (500 (pixel) × 500 (pixel)), the scan speed is 1 fps. In order to realize this, it is necessary to scan the laser beam at 500 lines per second. Accordingly, the rotation speed required for the scanning unit 863 to realize the scan speed of 1 fps is 500 × 60 × 1 = 30000 (rpm). Although it can be applied at a lower speed depending on the application, the motor provided in the rotation mechanism 867 still requires a rotation speed of, for example, about 5000 (rpm) to 30000 (rpm).

  In addition, the motor of the rotation mechanism 867 is required to suppress the shaft runout and shaft tilt (shaft collapse) of the rotating shaft during rotation to a smaller range. This is because if the position of the rotation axis of the motor fluctuates during rotation, the accuracy of the scanning position of the laser beam in the z-axis direction (that is, the accuracy of observation depth) may be reduced.

Further, in order to satisfy the rotational speed and the positional accuracy of the rotating shaft as described above, the rotating mechanism 867 is required to have a predetermined rigidity. Specifically, the rotating shaft of the motor of the rotation mechanism 867 must be designed to withstand centrifugal force (mrw ² ) acting on the scanning unit 863 during rotation (m is the mass of the scanning unit 863, r Is the distance from the rotation axis to the center of gravity of the scanning unit 863 as a rotating body, and w is the rotation angular velocity). Further, in order to maintain the positional accuracy of the rotating shaft, it is necessary that the bearing provided in the motor has high rigidity. For example, when the size of the scanning unit 863 that is a rotating body is too large compared to the performance of the motor of the rotating mechanism 867, an excessive centrifugal force acts on the rotating shaft of the motor. The demand for rigidity becomes severe. Therefore, it is also required to design in consideration of the dynamic balance between the motor and the scanning unit 863 that is a rotating body, and to configure the scanning unit 863 to be smaller and lighter.

  Further, in this embodiment, laser scanning in the y-axis direction and / or z-axis direction can be performed in synchronization with laser scanning in the x-axis direction due to rotation of the scanning unit 863. Therefore, in order to improve the accuracy of laser scanning, it is desirable that a high-resolution angle sensor (for example, a rotary encoder) for detecting the rotation angle of the motor of the rotation mechanism 867 with high accuracy is mounted together with the motor.

  Here, it is considered that, for example, the laser scanning endoscope apparatus 3 as shown in FIG. 16 satisfies these performances. In the laser scanning endoscope apparatus 3, for example, a scanning unit 663 and a rotation mechanism 667 need to be mounted in a lens barrel 661 having a diameter of about 10 (mm). Therefore, considering that other configurations are also provided in the lens barrel 661, the motor of the rotating mechanism 667 is, for example, 60% or less of the diameter of the lens barrel 661 (in the above example, 6 ( mm) or less), and the length along the lens barrel 661 is preferably 20 (mm) or less. For example, assuming that the NA of the objective lens 665 is 0.45, the positional accuracy of the rotating shaft of the motor is 0.01 (mm) or less for shaft deflection and 0.1 (deg) or less for shaft tilt. It is desirable that

  Thus, in the laser scanning endoscope apparatus 3, it is necessary to ensure rigidity while maintaining the position of the rotating shaft with high accuracy in a relatively small motor. The angle sensor is also required to have a high resolution and a small size. Therefore, when each component must be mounted in a relatively small housing such as the laser scanning endoscope apparatus 3, the conditions for designing the components such as the rotation mechanism 667 and the scanning unit 663 are as follows. May be relatively severe. On the other hand, as described above, the laser scanning microscope apparatus 6 is not required to be as small as the laser scanning endoscope apparatus 3. Therefore, since a larger motor can be used as the motor of the rotation mechanism 867, it is easier to design components such as the rotation mechanism 867 and the scanning unit 863.

  Here, as described in the above (1. Examination of laser scanning endoscope apparatus having other configurations), as a general existing technique, the laser scanning microscope apparatus has a relatively large configuration. Since the degree of freedom of design of the optical system is high, there can exist a configuration that simultaneously realizes “3. high NA” and “4. wide field of view” by appropriately designing the optical system. However, in the existing technology, the configuration of the optical system becomes complicated, and it is difficult to reduce the size and cost of the apparatus. On the other hand, in this embodiment, by scanning the laser beam by rotating the scanning unit 863, a wide field of view is realized with a simpler configuration even when the objective lens 865 having a relatively high NA is used. The In addition, by providing the astigmatism correction element 866, even when the observation depth is changed, it is possible to perform more accurate observation with less influence of astigmatism.

(7. Hardware configuration)
Next, the hardware configuration of the laser scanning observation apparatus according to the present embodiment will be described in detail with reference to FIG. FIG. 29 is a block diagram for explaining a hardware configuration of the laser scanning observation apparatus according to the present embodiment. The laser scanning observation apparatus shown in FIG. 29 can constitute the laser scanning endoscope apparatuses 1, 2, 3, the laser scanning probes 4, 5 and the laser scanning microscope apparatus 6 described above.

  Referring to FIG. 29, the laser scanning observation apparatus 900 mainly includes a CPU 901, a ROM 903, and a RAM 905. The laser scanning observation apparatus 900 further includes a host bus 907, a bridge 909, an external bus 911, an interface 913, a sensor 914, an input device 915, an output device 917, a storage device 919, a drive 921, a connection port 923, and a communication device. 925.

  The CPU 901 functions as an arithmetic processing unit and a control unit, and controls all or a part of the operation in the laser scanning observation apparatus 900 according to various programs recorded in the ROM 903, the RAM 905, the storage device 919, or the removable recording medium 927. . The ROM 903 stores programs used by the CPU 901, calculation parameters, and the like. The RAM 905 primarily stores programs used by the CPU 901, parameters that change as appropriate during execution of the programs, and the like. These are connected to each other by a host bus 907 constituted by an internal bus such as a CPU bus. In the present embodiment, the CPU 901, the ROM 903, and the RAM 905 correspond to, for example, the control units 180 and 280 illustrated in FIGS. 2 and 4A.

  The host bus 907 is connected to an external bus 911 such as a PCI (Peripheral Component Interconnect / Interface) bus via a bridge 909.

  The sensor 914 is, for example, a detection unit that detects biological information unique to the user or various types of information used to acquire the biological information. In the present embodiment, the sensor 914 corresponds to, for example, the photodetector 170 illustrated in FIGS. 2 and 4A. In addition, the sensor 914 includes, for example, each of a series of systems that scan the living tissue 500 with laser light and detect the return light including the endoscope 160 and the photodetector 170 illustrated in FIGS. 2 and 4A. Corresponds to the component. The sensor 914 may include, for example, a photodetector such as a photodiode or a PMT, and various imaging elements such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The sensor 914 may further include an optical system such as a lens and a light source used for imaging a living body part. The sensor 914 may be a microphone or the like for acquiring sound or the like. The sensor 914 may include various measuring devices such as a thermometer, an illuminometer, a hygrometer, a speedometer, and an accelerometer in addition to the above-described ones.

  The input device 915 is an operation unit operated by the user, such as a mouse, a keyboard, a touch panel, a button, a switch, and a lever. The input device 915 may be, for example, remote control means (so-called remote control) using infrared rays or other radio waves, or may be an external device such as a mobile phone or a PDA corresponding to the operation of the laser scanning observation device 900. The connection device 929 may be used. Furthermore, the input device 915 includes an input control circuit that generates an input signal based on information input by the user using the above-described operation means and outputs the input signal to the CPU 901, for example. In the present embodiment, the input device 915 corresponds to, for example, the input unit 195 illustrated in FIGS. 2 and 4A. The user of the laser scanning observation apparatus 900 operates the input device 915 to perform various operations related to driving of the laser scanning observation apparatus 900 such as a rotation mechanism, a parallel movement mechanism, and / or an observation depth adjustment mechanism. Data can be input and a processing operation can be instructed.

  The output device 917 is a device that can notify the user of the acquired information visually or audibly. Examples of such devices include CRT display devices, liquid crystal display devices, plasma display devices, EL display devices, display devices such as lamps, audio output devices such as speakers and headphones, printer devices, and the like. The output device 917 outputs, for example, results obtained by various processes performed by the laser scanning observation device 900. Specifically, the display device visually displays the results obtained by various processes performed by the laser scanning observation device 900 in various formats such as text, images, tables, and graphs. On the other hand, the audio output device converts an audio signal composed of reproduced audio data, acoustic data, and the like into an analog signal and outputs it. In the present embodiment, the output device 917 corresponds to, for example, the output unit 190 illustrated in FIGS. 2 and 4A. For example, on the display screen of the output device 917, image data relating to a living tissue acquired as a result of laser scanning is displayed.

  Although not clearly shown in FIGS. 2 and 4A, the laser scanning observation apparatus 900 may further include the following constituent members.

  The storage device 919 is a data storage device configured as an example of a storage unit of the laser scanning observation device 900. The storage device 919 includes, for example, a magnetic storage device such as an HDD (Hard Disk Drive), a semiconductor storage device, an optical storage device, or a magneto-optical storage device. The storage device 919 includes various data processed by the laser scanning observation apparatus 900, such as programs and various data executed by the CPU 901, various data acquired from the outside, and laser scanning in the laser scanning observation apparatus 900. Stores various data obtained as a result. In the present embodiment, for example, the storage device 919 stores a program for controlling laser scanning in the laser scanning observation apparatus 900, various conditions, and the like. For example, the storage device 919 stores image data related to living tissue acquired as a result of laser scanning.

  The drive 921 is a recording medium reader / writer, and is built in or externally attached to the laser scanning observation apparatus 900. The drive 921 reads information recorded on a removable recording medium 927 such as a mounted magnetic disk, optical disk, magneto-optical disk, or semiconductor memory, and outputs the information to the RAM 905. The drive 921 can also write a record to a removable recording medium 927 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory that is mounted. The removable recording medium 927 is, for example, a DVD medium, an HD-DVD medium, a Blu-ray (registered trademark) medium, or the like. Further, the removable recording medium 927 may be a Compact Flash (registered trademark) (Compact Flash: CF), a flash memory, an SD memory card (Secure Digital memory card), or the like. Further, the removable recording medium 927 may be, for example, an IC card (Integrated Circuit card) on which a non-contact IC chip is mounted, an electronic device, or the like. The drive 921 writes and reads various data processed by the laser scanning observation apparatus 900 to and from various removable recording media 927.

  The connection port 923 is a port for directly connecting various external devices to the laser scanning observation apparatus 900. Examples of the connection port 923 include a USB (Universal Serial Bus) port, an IEEE 1394 port, a SCSI (Small Computer System Interface) port, and the like. As another example of the connection port 923, there are an RS-232C port, an optical audio terminal, an HDMI (registered trademark) (High-Definition Multimedia Interface) port, and the like. By connecting the external connection device 929 to this connection port 923, the laser scanning observation apparatus 900 acquires various data directly from the external connection device 929 or provides various data to the external connection device 929. In this manner, the connection port 923 connects the laser scanning observation apparatus 900 and various external devices so that various data can be communicated. The laser scanning observation apparatus 900 transmits various data processed in the laser scanning observation apparatus 900, for example, image data relating to a living tissue acquired as a result of laser scanning, to various external devices via the connection port 923. can do.

  The communication device 925 is a communication interface configured with, for example, a communication device for connecting to a communication network (network) 931. The communication device 925 is, for example, a communication card for wired or wireless LAN (Local Area Network), Bluetooth (registered trademark), or WUSB (Wireless USB). Further, the communication device 925 may be a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), a modem for various communication, or the like. The communication device 925 can transmit and receive signals and the like according to a predetermined protocol such as TCP / IP, for example, with the Internet or other communication devices. Further, the communication network 931 connected to the communication device 925 is configured by a wired or wireless network, and may be, for example, the Internet, a home LAN, infrared communication, radio wave communication, satellite communication, or the like. . With the communication device 925, various data processed in the laser scanning observation device 900 can be transmitted and received between the laser scanning observation device 900 and various external devices. For example, the communication device 925 can transmit various data processed by the laser scanning observation device 900 to various external devices via the communication network 931. For example, image data relating to a living tissue acquired as a result of laser scanning may be transmitted by the communication device 925 to various external devices such as a database server.

  Heretofore, an example of the hardware configuration capable of realizing the function of the laser scanning observation apparatus 900 according to the present embodiment has been shown. Each component described above may be configured using a general-purpose member, or may be configured by hardware specialized for the function of each component. Therefore, it is possible to change the hardware configuration to be used as appropriate according to the technical level at the time of carrying out this embodiment.

  Note that a computer program for realizing each function related to laser scanning and image data acquisition in the laser scanning observation apparatus 900 as described above can be produced and mounted on a personal computer or the like. In addition, a computer-readable recording medium storing such a computer program can be provided. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. Further, the above computer program may be distributed via a network, for example, without using a recording medium.

(8. Summary)
As described above, according to a preferred embodiment of the present disclosure, the following effects can be obtained.

  According to the laser scanning endoscope apparatus 1 according to the first embodiment, the objective lens 165 rotates about the y axis in the lens barrel 161 as a rotation axis. Then, the laser beam is scanned in the x-axis direction. Thus, the field of view (FOV) in the laser scanning endoscope apparatus 1 is not limited by the off-axis characteristics of the objective lens 165 by scanning the laser beam by the rotation of the objective lens 165. Accordingly, in the laser scanning endoscope apparatus 1, the range facing the window portion 162 while the objective lens 165 is rotating (that is, the range in which the laser beam is scanned in the x-axis direction) is secured as the FOV. A wide field of view is realized even when the NA of the lens 165 is relatively high. Moreover, since the window part 162 provided in the endoscope 160 of the laser scanning endoscope apparatus 1 according to the first embodiment is formed with a predetermined thickness, the window part 162 is formed on a living tissue. Safety when contacting is ensured. Furthermore, according to the laser scanning endoscope apparatus 1 according to the first embodiment, the aberration correction element 166 that corrects the aberration generated when the laser light is focused on the living tissue before the window unit 162. Is provided. Here, the aberration correction performance of the aberration correction element 166 is appropriately set according to the characteristics and shape of the objective lens 165 and the window portion 162 so as to correct aberrations caused by the objective lens 165 and / or the window portion 162. May be. Therefore, in the laser scanning endoscope apparatus 1, while using an objective lens having a relatively high NA, safety is ensured by providing a predetermined thickness in the window portion, and the influence of aberration is suppressed. It becomes possible to simultaneously obtain a high-quality image.

  In the laser scanning endoscope apparatus 1, high resolution and a wide field of view can be ensured by rotating the objective lens 165. Therefore, by controlling the sampling rate of the laser scanning, it is possible to look over the living tissue over a wide range, or to enlarge the desired part as needed and observe it at a higher resolution. Observation is realized.

  Further, according to the laser scanning endoscope apparatus 2 according to the second embodiment, in addition to the effects obtained by the laser scanning endoscope apparatus according to the first embodiment described above, the following effects are obtained. It is done. That is, in the laser scanning endoscope apparatus 2, a laser beam is incident on the optical path changing element 164, and the objective lens 165 focuses the laser beam on a plurality of different spots of the living tissue 500. To do. Here, the laser light that constitutes the light beam may be laser light that has been modulated differently, and the laser scanning endoscope apparatus 2 has a demodulation function for these laser light, so The image signal corresponding to the return light can be selectively separated and acquired. Therefore, in the laser scanning endoscope apparatus 2, it is possible to scan a plurality of lines by the laser light irradiated to a plurality of spots while the scanning unit 163 rotates once. Therefore, a high scanning speed can be obtained even if the rotational speed of the scanning unit 163 is relatively small.

  In the laser scanning endoscope apparatuses 1 and 2 according to the first and second embodiments, the scanning unit may have a plurality of objective lenses. Since the scanning unit includes a plurality of objective lenses, it is possible to perform laser scanning of a plurality of lines using the plurality of objective lenses while the scanning unit rotates once. Therefore, since the number of lines that can be scanned can be increased by one rotation of the scanning unit, more efficient laser scanning is possible.

  In the laser scanning endoscope apparatuses 1 and 2 according to the first and second embodiments, the scanning unit may have a different rotation axis direction. For example, the window 162 is provided at the distal end in the longitudinal direction of the lens barrel 161 so as to have a surface substantially perpendicular to the longitudinal direction of the lens barrel 161, and the portion where the distal end of the lens barrel 161 is in contact with the window 161. Laser scanning is performed. Therefore, for example, even when the observation target site is present in a recessed portion in the body cavity where it is difficult to contact the outer wall of the lens barrel 161, it is possible to perform observation by laser scanning. Become.

  Furthermore, in the above (6. Configuration including observation depth adjustment mechanism), the case where the laser scanning observation apparatus according to the present embodiment includes the observation depth adjustment mechanism has been described. Further, the configuration of the laser scanning probe and the laser scanning microscope apparatus has been described as a configuration example of the laser scanning observation apparatus according to the present embodiment other than the endoscope apparatus. According to these configurations, in addition to the effects obtained in the first embodiment and / or the second embodiment described above, the following effects can be obtained.

  In the laser scanning observation apparatus described above (6. Configuration including observation depth adjustment mechanism), the observation depth adjustment mechanism is provided, so that laser scanning can be performed in the depth direction with respect to the observation target. Therefore, it becomes possible to observe the observation target three-dimensionally, and it is possible to acquire more information about the observation target. In addition, the laser scanning observation apparatus may be provided with an astigmatism correction element that corrects the astigmatism with a correction amount corresponding to a change in astigmatism accompanying a change in observation depth. By providing an astigmatism correction element having such characteristics, even when the observation depth is changed, it is possible to perform more accurate observation with less influence of astigmatism.

  For example, when detecting fluorescence as return light as in observation using two-photon excitation, a double-clad optical fiber may be used as an optical fiber, and a chromatic aberration correction element may be provided. By using the double clad optical fiber, the fluorescence can be guided by the inner clad, so that the fluorescence can be collected in a wider area, so that the light collection efficiency can be improved. The chromatic aberration correcting element is designed to correct chromatic aberration caused by the difference in wavelength between laser light and fluorescence. Therefore, by providing an astigmatism correction element having such characteristics, it is possible to further improve the efficiency of condensing fluorescence onto the optical fiber.

  The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, but the technical scope of the present disclosure is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field of the present disclosure can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that it belongs to the technical scope of the present disclosure.

  For example, the application of the technology according to each of the above-described embodiments is not limited to microscopic observation, and may be used for other applications. For example, the present invention can be applied to various optogenetic manipulations including control of ion channels of nerve cells that can control activity and inactivity by photoexcitation.

  In addition, for example, the following configuration may be further provided for each configuration described above.

  For example, the laser light source 110 may further include a configuration that dynamically controls the timing of emitting the laser light. Then, the laser light source 110 may emit the laser light only at the timing when the living tissue 500 is irradiated with the laser light in synchronization with the rotation of the scanning unit by the rotation mechanism 167. Power consumption can be reduced by adopting a configuration in which laser light is emitted only when the laser light source 110 is necessary.

  For example, the laser light source 110 may further include a configuration that dynamically controls the intensity (power) of the emitted laser light. Generally, when acquiring enlarged image data, as the image data is enlarged (zoomed), the light reception integration time per pixel is shortened, and the brightness of the acquired image data decreases. Therefore, the laser light source 110 may control the intensity of the emitted laser light according to the size of the image data to be acquired. For example, when acquiring enlarged image data, the laser light source 110 may increase the intensity of the emitted laser light. Further, the laser light emission timing and intensity control of these laser light sources 110 may be controlled by the control unit 180, for example.

  The rotation mechanism 167 may further include a rotation system servo mechanism for stabilizing control of rotation driving of the scanning unit. The rotation system servo mechanism can stabilize the rotation of the scanning unit by, for example, detecting the amount of eccentricity while the scanning unit is rotating and controlling the rotation speed and the like. Note that aberrations such as astigmatism may vary depending on the amount of eccentricity of the scanning unit. Therefore, information on the amount of eccentricity of the scanning unit is fed back to the aberration correction element, and the correction amount by the aberration correction element is dynamically controlled according to the fluctuation of aberration such as astigmatism calculated from the amount of eccentricity. Also good.

  Further, as described above (2. First Embodiment), the endoscope 160 may include an imaging unit that captures an image of the inside of the body cavity of the patient. For example, the imaging unit may include a wide-angle bright-field shooting camera. When the imaging unit has a wide-angle bright-field imaging camera, the observation target site to be observed in detail is searched for while referring to the wide-angle video captured by the imaging unit, and the window unit 162 is located at the found observation target site. Laser scanning may be carried out by bringing them into contact with each other.

The following configurations also belong to the technical scope of the present disclosure.
(1) A window part provided in a partial region of a tubular casing and in contact with or in close proximity to a living tissue in a body cavity of a measurement subject to be observed; provided inside the casing; and through the window part An objective lens for condensing laser light on the living tissue, and an optical path change for guiding the laser light guided in the casing along the long axis direction of the casing to the lens surface of the objective lens An element, an aberration correction element that is provided upstream of the window portion and corrects an aberration that occurs when the laser light is condensed on the living tissue, and the laser light scans the living tissue. An endoscope comprising: a rotation mechanism that rotates at least the objective lens within the housing with a rotation axis that is orthogonal to the optical axis of the objective lens and does not pass through the objective lens.
(2) The endoscope according to (1), wherein the aberration correction element corrects at least astigmatism caused by the window portion.
(3) The endoscope according to (2), wherein the aberration correction element includes at least one cylindrical lens.
(4) The endoscope according to any one of (1) to (3), wherein the rotation mechanism integrally rotates the optical path changing element, the aberration correction element, and the objective lens.
(5) The endoscope according to any one of (1) to (4), further including a translation mechanism that translates at least the objective lens in the casing in the rotation axis direction.
(6) The light beam of the laser light is incident on the optical path changing element, and the objective lens focuses the light beam of the laser light on a plurality of different spots of the living tissue. The endoscope according to any one of (5).
(7) The endoscope according to (6), wherein the light beam of the laser light is configured by the laser light modulated into a plurality of different states.
(8) The endoscope according to any one of (1) to (7), wherein the window portion is provided in a partial region of a side wall substantially parallel to a long axis direction of the casing.
(9) A plurality of the objective lenses are provided, and the plurality of objective lenses are opposed to the inner wall of the casing at substantially the same position in the major axis direction of the casing, and along the outer peripheral direction of the casing. The endoscope according to (8), which is disposed at a predetermined interval.
(10) The apparatus further includes a polarization modulation element that is provided before the optical path changing element and changes a polarization direction of the laser light incident on the optical path changing element, and the optical path changing element has a predetermined polarization direction. A polarization beam splitter that changes an optical path of light, wherein the polarization beam splitter converts the laser light whose polarization direction has been changed by the polarization modulation element to a plurality of objective lenses according to the polarization direction of the laser light. The endoscope according to (9), wherein light is guided to the objective lens facing the window portion.
(11) The optical path changing element is a MEMS mirror that can dynamically control a reflection direction of the incident laser light, and the MEMS mirror transmits the incident laser light to the window of the plurality of objective lenses. The endoscope according to (9), wherein light is guided to the objective lens facing the part.
(12) An optical path branching element that is provided in a preceding stage of the optical path changing element and branches the laser light incident on the optical path changing element into a plurality of optical paths, wherein the aberration is provided in a stage preceding the plurality of objective lenses. A correction element and an optical path changing element are provided, and each of the laser beams branched by the optical path branching element sequentially passes through the optical path changing element and the aberration correction element, and each of the plurality of objective lenses The endoscope according to (9), which is guided to the center.
(13) The aberration correction element and the optical path changing element are provided in the front stage of the plurality of objective lenses, respectively, and are provided in the front stage of the plurality of optical path changing elements, respectively, and only in the corresponding optical path changing element. An incident window portion for allowing laser light to enter, wherein the laser light is guided in the housing in a state where an optical axis of the laser light is maintained at a predetermined position with respect to the housing; In (9), the laser beam incident from the incident window portion corresponding to the light irradiation position is sequentially guided to the aberration correction element, the optical path changing element, and the objective lens corresponding to the incident window portion. The endoscope described.
(14) Any one of (1) to (7), wherein the window portion is provided at a distal end portion in a major axis direction of the casing with a surface substantially perpendicular to the major axis direction of the casing. The endoscope according to item 1.
(15) The space between the objective lens and the window portion is immersed in a liquid having substantially the same refractive index as the refractive index of the objective lens and the refractive index of the window portion. The endoscope according to any one of (14).
(16) The endoscope according to any one of (1) to (15), further including an optical axis direction moving mechanism that translates at least the objective lens in the optical axis direction of the objective lens.
(17) A window portion provided in a partial region of the tubular casing and in contact with or close to a living tissue in a body cavity of a measurement subject to be observed; and provided inside the casing and passing through the window portion An objective lens for condensing laser light on the living tissue, and an optical path change for guiding the laser light guided in the casing along the long axis direction of the casing to the lens surface of the objective lens An element, an aberration correction element that is provided upstream of the window portion and corrects an aberration that occurs when the laser light is condensed on the living tissue, and the laser light scans the living tissue. An endoscope having a rotation mechanism that rotates at least the objective lens within the housing with a rotation axis that is orthogonal to the optical axis of the objective lens and does not pass through the objective lens, and the laser light is collected in the living tissue. Lighted A photodetector for detecting Jill return light, based on the detected the return light, and a control unit for generating image data for the body tissue, the laser scanning endoscope apparatus.
(18) A laser beam is guided into a tubular casing in the endoscope, and the laser beam is incident on an optical path changing element provided in the casing. Changing the optical path of the laser light guided along the long axis direction of the body, guiding the laser light to the lens surface of the objective lens provided inside the housing, and Condensing the laser light on the biological tissue by the objective lens through a window portion that is provided in a partial area and contacts or approaches the biological tissue in the body cavity of the measurement subject to be observed; Rotating at least the objective lens within the housing with a rotation axis that is orthogonal to the optical axis of the objective lens and does not pass through the objective lens so that light scans the biological tissue, and the window portion than The stage, the aberration correcting element is provided which corrects an aberration generated when the laser beam is focused on the biological tissue, the laser scanning method.

The following configurations also belong to the technical scope of the present disclosure.
(1) A window portion that is provided in a partial region of the housing and is in contact with or close to the observation target; an objective lens that focuses the laser light on the observation target through the window portion; An optical path changing element that changes the traveling direction of the laser light toward the window portion, and an astigmatism that is provided before the window portion and is generated when the laser light is condensed on the observation target. Astigmatism correction elements to be corrected, and at least the optical path changing element is rotated about a rotation axis perpendicular to the incident direction of the laser light to the window portion so that the laser light scans the observation target. A rotation mechanism, and the astigmatism correction element is applied with a correction amount corresponding to a change in astigmatism accompanying a change in observation depth, which is a depth of the condensing position of the laser beam in the observation target. Correcting astigmatism, the laser-scanning examination apparatus.
(2) The astigmatism correction element includes a lens configured to allow the laser light to pass through at least two cylindrical surfaces or toroidal surfaces, and is rotated together with the optical path changing element by the rotation mechanism. The laser scanning observation apparatus according to (1).
(3) The laser scanning observation apparatus according to (2), wherein the astigmatism correction element is a meniscus lens having cylindrical surfaces formed on both sides.
(4) The laser scanning according to (1), wherein the astigmatism correction element is an optical member including a drive element that dynamically changes an astigmatism correction amount in accordance with a change in the observation depth. Mold observation device.
(5) The apparatus further comprises a translation mechanism that scans the laser light in the direction of the rotation axis with respect to the observation target by translating at least the optical path changing element in the direction of the rotation axis. The laser scanning observation apparatus according to any one of to (4).
(6) Any one of (1) to (5), further including an observation depth adjustment mechanism that scans the laser light in the depth direction with respect to the observation target by changing the observation depth. 2. A laser scanning observation apparatus according to item 1.
(7) The observation depth adjustment mechanism includes a collimator lens that converts the laser light into substantially parallel light and guides the laser light to the optical path changing element and the astigmatism correction element, and a movement that moves the collimator lens in the optical axis direction. The laser scanning observation apparatus according to (6), including a mechanism.
(8) The laser scanning observation apparatus acquires information about the observation target by detecting fluorescence generated by irradiating the observation target with the laser light as return light, and the laser beam and the laser The laser scanning observation apparatus according to any one of (1) to (7), further including a chromatic aberration correction element that corrects chromatic aberration caused by a difference in wavelength from fluorescence.
(9) The chromatic aberration correcting element is a cemented lens that functions as a parallel plate for light in the wavelength band corresponding to the laser light and functions as a concave lens for light in the wavelength band corresponding to the fluorescence. The laser scanning observation apparatus according to (8), wherein:
(10) The laser beam is incident on the optical path changing element, and the objective lens focuses the laser beam on a plurality of different spots of the observation target. The laser scanning observation apparatus according to any one of (9).
(11) The laser scanning observation apparatus according to (10), wherein the light beam of the laser light is configured by the laser light modulated into a plurality of different states.
(12) The laser scanning observation apparatus according to (10) or (11), wherein the light beam of the laser light is guided into the housing by a plurality of optical fibers.
(13) The laser scanning observation apparatus according to (10) or (11), wherein the laser light beam is guided into the housing by a multi-core optical fiber having a plurality of cores.
(14) A polarization modulation element that is provided in a preceding stage of the optical path changing element and changes a polarization direction of the laser light incident on the optical path changing element, wherein the optical path changing element has a predetermined polarization direction. A polarization beam splitter that changes an optical path of the light, wherein the polarization beam splitter changes the traveling direction of the laser light whose polarization direction has been changed by the polarization modulator according to the polarization direction of the laser light. The laser scanning observation apparatus according to any one of (1) to (13), which is changed toward
(15) An optical path branching element that is provided in a preceding stage of the optical path changing element and splits the laser light incident on the optical path changing element into a plurality of optical paths, and for each of the plurality of optical paths, A point aberration correcting element, the optical path changing element, and the objective lens are provided, respectively, and a plurality of traveling directions of the laser light branched by the optical path branching element are perpendicular to the rotation axis direction by the optical path changing element. The laser scanning observation apparatus according to any one of (1) to (13), wherein the laser scanning observation apparatus is changed to the direction of (1).
(16) A housing for storing at least a plurality of the optical path changing elements and rotating together with the plurality of the optical path changing elements is provided, and the laser beam is incident on a wall surface on which the laser light is incident. An incident window portion that is incident on each of the elements is formed, and the astigmatism correction element and the objective lens are provided for each of the plurality of incident window portions, and the laser beam has an optical axis of the laser beam. The light is guided through the housing while being held at a predetermined position with respect to the housing, and sequentially irradiated to the plurality of incident window portions as the housing rotates, corresponding to the irradiation position of the laser light. The laser light incident from the incident window portion is guided toward the window portion by the optical path changing element (1) to (13). Re or laser-scanning examination apparatus according to (1).
(17) The casing has a cylindrical shape, and the window portion is provided on a side wall substantially parallel to the long axis direction of the casing, and has a cylindrical curved surface conforming to the shape of the side wall of the casing. The laser scanning observation apparatus according to any one of (1) to (16).
(18) The casing has a cylindrical shape, and the window portion is provided at a distal end portion in a major axis direction of the casing with a surface substantially perpendicular to the major axis direction of the casing. The laser scanning observation apparatus according to any one of (1) to (16).
(19) The objective lens is provided between the optical path changing element and the window portion,
The space between the objective lens and the window portion is any one of (1) to (18), wherein the space is immersed in a liquid having a refractive index substantially the same as the refractive index of the window portion. Laser scanning observation device.
(20) The casing is a lens barrel of an endoscope, and the window portion provided in a partial region of the lens barrel is in contact with or close to a living tissue in a body cavity of a human or animal to be observed, The laser scanning observation apparatus according to any one of (1) to (19), wherein the laser beam is scanned with respect to a living tissue.
(21) The window portion is in contact with or close to the surface of a human or animal body to be observed, and the laser light is scanned from the body surface to a living tissue at a predetermined depth. (19) The laser scanning observation apparatus according to any one of (19).
(22) The laser scanning observation apparatus further includes a stage on which the observation target is placed, and the laser light scans the observation target through the window provided in at least a partial region of the stage. The laser scanning observation apparatus according to any one of (1) to (19).
(23) Incident laser light into an optical path changing element provided inside the casing; and changing a traveling direction of the laser light guided through the casing by the optical path changing element; Irradiating the observation target with the laser light that is collected by the objective lens and corrected for astigmatism by the astigmatism correction element through a window portion that is provided in a partial region and that is in contact with or close to the observation target. And rotating at least the optical path changing element with a rotation axis perpendicular to an observation direction which is an incident direction of the laser light to the observation target, so that the laser light scans the living tissue, The astigmatism correction element includes the astigmatism with a correction amount corresponding to a change in astigmatism accompanying a change in observation depth, which is a depth of the condensing position of the laser beam in the observation target. correction That, laser scanning method.

1, 2, 3 Laser scanning endoscope apparatus 4, 5 Laser scanning probe 6 Laser scanning microscope apparatus 110, 810 Laser light source 110
120, 820 Beam splitter 130, 150 Light guide lens for optical fiber 140, 241, 242, 243, 340, 641, 710, 740, 760 Optical fiber 160, 360, 400, 450, 470 Endoscope 161 Lens barrel 162, 662, 732, 782, 862 Window part 163, 363, 370, 380, 390, 420, 460, 480, 663, 733, 783, 863 Scan part 164, 364, 421, 422, 664, 734, 784, 864 Optical path Change element 165, 365, 366, 422, 665, 735, 785, 865 Objective lens 166, 367, 368, 423, 461 Aberration correction element 167, 667, 737, 787, 867 Rotation mechanism 168, 668, 738, 788, 868 translation mechanism 169, 69, 424, 469, 669, 739, 789, 869 Housing 170, 870 Photodetector 180, 280 Control unit 181 Image signal acquisition unit 182 Image signal processing unit 183 Drive control unit 184 Display control unit 190 Output unit 195 Input unit 240 Optical fiber bundle 281 Image signal acquisition unit (optical demodulation unit)
372 Polarizing beam splitter 381 MEMS mirror 391 Optical path branching element 463 First optical path changing element 464 Second optical path changing element 465 First objective lens 466 Second objective lens 620 Cylindrical concave / convex lens pair 621 Concave cylindrical lens 622 Convex cylindrical lens 630 Cylindrical meniscus lens 640 Cylindrical plano-convex lens 650, 720, 770, 850 Collimator lens 661, 731, 781 Case 666, 736, 786, 866 Astigmatism correction element 670, 740, 790, 840 Chromatic aberration correction element

Claims (23)

A window portion provided in a partial region of the housing and in contact with or close to the observation target;
An objective lens that focuses laser light on the observation object through the window portion;
An optical path changing element that changes the traveling direction of the laser light guided in the housing toward the window portion;
An astigmatism correction element that is provided before the window portion and corrects astigmatism generated when the laser beam is focused on the observation target;
A rotation mechanism that rotates at least the optical path changing element at a rotation axis perpendicular to the direction of incidence of the laser light on the window portion so that the laser light scans the observation target;
With
The astigmatism correction element corrects the astigmatism with a correction amount corresponding to a change in astigmatism accompanying a change in observation depth, which is a depth of a condensing position of the laser light in the observation target; Laser scanning observation device. The astigmatism correction element includes a lens configured to allow the laser light to pass through at least two cylindrical surfaces or toroidal surfaces, and is rotated together with the optical path changing element by the rotation mechanism.
The laser scanning observation apparatus according to claim 1. The astigmatism correction element is a meniscus lens having cylindrical surfaces formed on both sides.
The laser scanning observation apparatus according to claim 2. The astigmatism correction element is an optical member including a drive element that dynamically changes the correction amount of astigmatism according to the change in the observation depth.
The laser scanning observation apparatus according to claim 1. A translation mechanism that scans the laser light in the direction of the rotation axis with respect to the observation target by translating at least the optical path changing element in the direction of the rotation axis;
The laser scanning observation apparatus according to claim 1. An observation depth adjustment mechanism that scans the laser beam in the depth direction with respect to the observation object by changing the observation depth;
The laser scanning observation apparatus according to claim 1. The observation depth adjustment mechanism includes a collimator lens that makes the laser light substantially parallel light and guides the laser light to the optical path changing element and the astigmatism correction element, a moving mechanism that moves the collimator lens in the optical axis direction, including,
The laser scanning observation apparatus according to claim 6. The laser scanning observation apparatus obtains information about the observation object by detecting fluorescence generated by the laser light being applied to the observation object as return light,
A chromatic aberration correction element that corrects chromatic aberration caused by a difference in wavelength between the laser beam and the fluorescence;
The laser scanning observation apparatus according to claim 1. The chromatic aberration correcting element is a cemented lens that functions as a parallel plate for light in the wavelength band corresponding to the laser light and functions as a concave lens for light in the wavelength band corresponding to the fluorescence.
The laser scanning observation apparatus according to claim 8. The light beam of the laser beam is incident on the optical path changing element,
The objective lens focuses the light flux of the laser light on a plurality of different spots of the observation target.
The laser scanning observation apparatus according to claim 1. The light beam of the laser beam is constituted by the laser beam modulated into a plurality of different states.
The laser scanning observation apparatus according to claim 10. The laser beam is guided into the housing by a plurality of optical fibers.
The laser scanning observation apparatus according to claim 10. The laser beam is guided into the housing by a multi-core optical fiber having a plurality of cores.
The laser scanning observation apparatus according to claim 10. A polarization modulation element that is provided in a preceding stage of the optical path changing element and changes a polarization direction of the laser light incident on the optical path changing element;
Further comprising
The optical path changing element is a polarization beam splitter that changes an optical path of the laser light having a predetermined polarization direction,
The polarization beam splitter changes the traveling direction of the laser light whose polarization direction has been changed by the polarization modulation element, toward the window portion according to the polarization direction of the laser light.
The laser scanning observation apparatus according to claim 1. An optical path branching element that is provided in a preceding stage of the optical path changing element and branches the laser light incident on the optical path changing element into a plurality of optical paths;
Further comprising
For each of the plurality of optical paths, the astigmatism correction element, the optical path changing element, and the objective lens are provided, respectively.
Respective traveling directions of the laser light branched by the optical path branching element are changed by the optical path changing element into a plurality of directions perpendicular to the rotation axis direction.
The laser scanning observation apparatus according to claim 1. A housing for storing at least a plurality of the optical path changing elements and rotating together with the optical path changing elements;
An incident window portion for allowing the laser light to enter each of the plurality of optical path changing elements is formed on the wall surface of the housing on which the laser light is incident.
The astigmatism correction element and the objective lens are provided for each of the plurality of incident window portions,
The laser light is guided through the housing in a state where the optical axis of the laser light is maintained at a predetermined position with respect to the housing, and sequentially enters the plurality of incident window portions as the housing rotates. Irradiated,
Laser light incident from the incident window portion corresponding to the irradiation position of the laser light is guided toward the window portion by the optical path changing element.
The laser scanning observation apparatus according to claim 1. The housing has a cylindrical shape;
The window portion is provided on a side wall substantially parallel to the long axis direction of the casing, and has a cylindrical curved surface conforming to the shape of the side wall of the casing.
The laser scanning observation apparatus according to claim 1. The housing has a cylindrical shape;
The window portion is provided at a distal end portion in the major axis direction of the casing with a surface substantially perpendicular to the major axis direction of the casing.
The laser scanning observation apparatus according to claim 1. The objective lens is provided between the optical path changing element and the window portion,
The space between the objective lens and the window part is immersed in a liquid having a refractive index substantially the same as the refractive index of the window part.
The laser scanning observation apparatus according to claim 1. The housing is an endoscope barrel;
The window portion provided in a partial region of the lens barrel is in contact with or close to a living tissue in a body cavity of a human or animal to be observed, and the laser light is scanned with respect to the living tissue;
The laser scanning observation apparatus according to claim 1. The window portion is in contact with or close to the surface of a human or animal body to be observed, and the laser light is scanned with respect to a living tissue at a predetermined depth from the body surface.
The laser scanning observation apparatus according to claim 1. The laser scanning observation apparatus further includes a stage on which the observation target is placed,
The laser beam is scanned with respect to the observation object through the window provided in at least a partial region of the stage.
The laser scanning observation apparatus according to claim 1. Making laser light incident on an optical path changing element provided inside the housing;
By changing the traveling direction of the laser light guided in the housing by the optical path changing element, and by an objective lens through a window portion provided in a partial area of the housing and in contact with or close to an observation target Irradiating the observation target with the laser light that has been condensed and the astigmatism corrected by the astigmatism correction element;
Rotating at least the optical path changing element with a rotation axis perpendicular to an observation direction which is an incident direction of the laser light to the observation target so that the laser light scans the observation target;
Including
The astigmatism correction element corrects the astigmatism with a correction amount corresponding to a change in astigmatism accompanying a change in observation depth, which is a depth of a condensing position of the laser light in the observation target; Laser scanning method.

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