JP2018101092A - Light field microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light field microscope capable of forming illumination light having a uniform luminance distribution in an optical axis direction of the objective lens in an area on a specimen used for imaging with simple configuration at a low cost.SOLUTION: A light field microscope 10 includes: an object lens 11 for capturing light from specimen S; and an illumination unit for irradiating a sample S with a beam of illumination light from a direction perpendicular to the optical axis of the object lens 11. The illumination unit includes: a light source 25 that emits illumination light; a multimode fiber 1 that guides the beam of illumination light from the light source 25 and outputs the same from an exit end face; and an illumination optical system 18 that projects an image on an exit end face 1a on the optical axis of the object lens 11. The illumination unit applies the beam of the illumination light so that the illumination light has a constant thickness in an optical axial direction of the object lens 11 on a projection plane on which an image is projected by the illumination optical system 18.SELECTED DRAWING: Figure 1

Description

  It relates to a light field microscope.

  In a light field microscope, three-dimensional information in a certain range (determined by the focal depth of the objective lens) can be acquired by one imaging, so adjustment work for adjusting the focal position during imaging is omitted and the number of imaging is reduced. It is possible to perform more efficient observation. A technique relating to such a light field microscope is disclosed in Patent Document 1, for example.

US Patent No. 7723662

  On the other hand, in the light field microscope, since information within the depth of focus is acquired by one imaging as described above, a wider illumination range in the optical axis direction of the objective lens is used for imaging compared to other microscopes. . That is, in the wide illumination range used for imaging, the unevenness of the luminance distribution of the illumination light in the optical axis direction of the objective lens can affect the observation of the specimen. In particular, when the amount of fluorescence is quantified, the influence of the nonuniformity of the luminance distribution is great.

  When a general point light source is used, the formed illumination light has a luminance distribution in which the luminance is attenuated as it is defocused from the focal position, and is sufficiently uniform in the optical axis direction of the objective lens in observation using a light field microscope. It cannot be said that it has sex.

  In light of the above circumstances, in the present invention, a light field microscope capable of forming illumination light having a uniform luminance distribution in the optical axis direction of the objective lens in an area on a specimen used for imaging with an inexpensive and simple configuration. The purpose is to provide.

  The light field microscope according to an aspect of the present invention includes an objective lens that captures light from the specimen, and an illumination device that irradiates the specimen with illumination light from a direction orthogonal to the optical axis of the objective lens, and the illumination The apparatus projects a light source that emits the illumination light, a multi-mode fiber that guides the illumination light from the light source and emits the light from an exit end face, and an image of the exit end face on the optical axis of the objective lens. An illumination optical system, and the illumination device emits the illumination light so that the illumination light has a certain thickness in the optical axis direction of the objective lens on a projection surface projected by the illumination optical system. Irradiating.

  According to the present invention, it is possible to provide a light field microscope capable of forming illumination light having a uniform luminance distribution in the optical axis direction of an objective lens in an area on a specimen used for imaging with an inexpensive and simple configuration. it can.

The figure which shows the structure of the light field microscope of 1st Embodiment. The figure which shows a mode that the output end surface of the multimode fiber of 1st Embodiment was seen from the Z direction. The figure which shows a mode that the field stop of 1st Embodiment was seen from the Z direction. The figure which shows the function structure of the control apparatus of 1st Embodiment. The figure which shows the structure of the light field microscope of 2nd Embodiment. The figure which shows the structure of the light field microscope of 3rd Embodiment. The figure which shows a mode that the output end surface of the multimode fiber of 3rd Embodiment was seen from the Z direction. The figure which shows a mode that the field stop of 3rd Embodiment was seen from the Z direction. The figure which shows a mode that the brightness stop of 3rd Embodiment was seen from the Z direction. The figure which shows the function structure of the control apparatus of 3rd Embodiment. The figure which shows the structure of the light field microscope of 4th Embodiment. The figure which shows a mode that the output end surface of the multimode fiber of 4th Embodiment was seen from the Z direction. The figure which shows a mode that the field stop in one structural example of 4th Embodiment was seen from the Z direction.

  The light field microscope 10 according to the first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a light field microscope 10.

  The light field microscope 10 includes a light source 25, a multimode fiber 1, an illumination optical system 18, a stage 9 on which a light transmissive container 8 containing a specimen S is installed, an observation optical system 19, and a light field microscope. And a control device 20 that controls various components in the system 10. In the following, the optical axis direction of the illumination optical system 18 is referred to as the Z direction, the optical axis direction of the observation optical system 19 is referred to as the X direction, and the direction orthogonal to the X direction and the Z direction is referred to as the Y direction. In FIG. 1, the X direction and the Z direction are shown.

  The container 8 is a cuvette, for example. The specimen S is an ecological sample such as zebrafish and is enclosed in the container 8 together with agarose.

  In the light field microscope 10, the light source 25, the multimode fiber 1, and the illumination optical system 18 function as an illumination device that irradiates the specimen S with illumination light from a direction orthogonal to the optical axis of the objective lens 11 of the observation optical system 19. To do.

  The light source 25 is a light source that emits laser light for generating fluorescence from the specimen S as illumination light. Illumination light emitted from the light source 25 is guided through the multimode fiber 1.

  The multimode fiber 1 is an optical fiber that transmits light while reflecting light in a plurality of different modes. The multimode fiber 1 guides the illumination light from the light source 25 and emits it from the emission end face 1a.

  FIG. 2 is a diagram illustrating a state in which the emission end face 1a of the multimode fiber 1 is viewed from the Z direction. The multimode fiber 1 includes a core 1b that is a rectangular core having a rectangular shape. The core 1b is a rectangular core having a core size of 200 × 800 μm, and the injection NA of the core 1b is 0.1. Here, the core 1b of the multimode fiber 1 has a direction in which any two of the four sides forming the outer periphery are orthogonal to the optical axis of the objective lens 11 included in the observation optical system 19 (that is, the Y direction). It is arranged to face. In addition, the length of each of the two sides orthogonal to the optical axis of the objective lens 11 is formed to be larger than the length of each of the two sides parallel to the optical axis of the objective lens 11 of the core 1b. Here, two sides parallel to the Y direction are two sides in the longitudinal direction.

  The illumination light emitted by the multimode fiber 1 is a light beam having a rectangular cross section of 200 μm in the X direction and 800 μm in the Y direction on the emission end face 1a, and has a uniform luminance distribution on the emission end face 1a. The luminous flux has. Therefore, by projecting the image of the emission end face 1a onto the sample S as described later, a light beam having a uniform luminance distribution on the projection surface on the sample S can be formed. For example, when light from a point light source is emitted through an illumination optical system without using an optical fiber, or when a single mode fiber whose emission end face can be regarded as a point light source is used, the luminance distribution on the sample is not uniform on the XY plane. It has a luminance distribution. By using a multi-mode fiber as in this configuration, a light beam of illumination light (also referred to as illumination light beam) on the projection plane that is a cross-section on the XY plane (also referred to as XY cross-section) has a uniform luminance distribution. Can be formed.

  The illumination optical system 18 includes lenses 2, 3, 5, 7, a field stop 4, and a brightness stop 6. The illumination optical system 18 projects an image of the emission end face 1 a of the multimode fiber 1 onto the optical axis of the objective lens 11 of the observation optical system 19. Hereinafter, each configuration of the illumination optical system 18 will be described.

  The lenses 2 and 3 relay the illumination light emitted from the multimode fiber 1 and form an intermediate image in the illumination optical system 18. Specifically, the lenses 2 and 3 enlarge the image of the illumination light on the exit end face 1a twice and project it to the intermediate image position. That is, an image of a rectangular light beam on the exit end face 1a having a size of 400 × 1600 μm is projected at this intermediate image position. The lenses 2 and 3 are configured telecentric.

  The field stop 4 is a stop (first stop) disposed at or near the intermediate image position formed by the lenses 2 and 3. FIG. 3 is a diagram illustrating a state in which the field stop 4 is viewed from the Z direction. The field stop 4 is composed of four stop plates (stop plates 4a, 4b, 4c, 4d), and forms a rectangular shape on the outer periphery of the region through which the illumination light of the field stop 4 passes. Of the four sides forming the rectangular shape, any two opposite sides are arranged so as to be orthogonal to the optical axis of the objective lens 11. Here, two sides formed by the diaphragm plates 4 a and 4 c are orthogonal to the optical axis of the objective lens 11. The field stop 4 can adjust the aperture width by moving the four stop plates in the direction of the arrow in FIG. 3, and the rectangular width of the light beam projected by the lenses 2 and 3 (each The length of the side) can be adjusted arbitrarily.

  The adjustment of the aperture width in the field stop 4 is controlled by the control device 20. Adjustment of the aperture width by the field stop 4 is performed while maintaining symmetry about the optical axis of the illumination optical system 18. The opening width adjusted at this time may be determined in advance corresponding to the type of the objective lens 11 to be used. If the magnification of the objective lens 11 is different, the depth of focus changes. Therefore, it is desirable to change the field stop 4 so that the aperture width matches the depth of focus at the time of observation. For example, the control device 20 records the type of the objective lens 11 to be used and the aperture width suitable for each objective lens, and controls the aperture width of the field stop 4 according to switching of the objective lens 11.

  Further, the field stop 4 is not a variable stop composed of a plurality of stop plates as shown in FIG. 3, but a structure in which a plurality of stops having different sizes are switchably installed in the optical path. Also good.

  The lenses 5 and 7 relay the intermediate image formed by the lenses 2 and 3 and project the intermediate image on the sample S on the optical axis of the objective lens 11 at approximately the same magnification. The lenses 5 and 7 are configured to be telecentric. That is, the lenses 2 and 3 and the lenses 5 and 7 are configured to be telecentric, and the illumination optical system 18 is configured to be telecentric.

  In addition, the illumination optical system 18 includes a brightness stop 6 (second stop) at the pupil position of the lens 7, that is, the exit pupil position of the illumination optical system 18. The brightness stop 6 has a rectangular opening similar to the field stop 4, and the opening width thereof can be adjusted in the X direction and the Y direction. By adjusting the aperture stop 6, the size of the XY cross section of the illumination light beam can be adjusted. For example, when the aperture stop 6 is reduced, the amount of light applied to the sample S is reduced, but the change in the size of the XY section of the illumination light beam in the illumination optical axis direction (Z direction) can be suppressed. Conversely, by expanding the aperture stop 6, the effect of suppressing the change in the size of the XY cross section of the illumination light beam is weakened, but the amount of light irradiated on the sample S increases. Thus, in the adjustment of the aperture stop 6, the irradiation light quantity and the effect of suppressing the change in the size of the XY cross section of the illumination light beam have a trade-off relationship, and the brightness depends on the characteristics of the sample S. It is desirable that the diaphragm 6 be adjusted. The adjustment of the brightness diaphragm 6 is controlled by the control device 20.

  Further, the aperture stop 6 may be a variable stop configured by a plurality of stop plates like the field stop 4, and a configuration in which a plurality of apertures having different sizes are switchably installed in the optical path. It may be. That is, each of the first diaphragm and the second diaphragm is configured so that the degree of diaphragm can be varied, or can be switched to another diaphragm having a different size.

  The characteristics of the configuration of the illumination device (light source 25, multimode fiber 1, illumination optical system 18) are summarized below.

  The illumination light from the light source 25 is applied to the specimen S through the multimode fiber 1 and the illumination optical system 18. Since an image having a uniform luminance distribution on the exit end face 1a of the multimode fiber 1 is projected, illumination light having a uniform luminance distribution in the cross section on the XY plane on the optical axis of the objective lens 11 is sample S. Can be irradiated.

  Further, the light beam formed on the output end face 1a of the multimode fiber 1 has a rectangular cross section in which two opposite sides on the XY plane face a direction orthogonal to the optical axis of the objective lens 11 (that is, the Y direction). Accordingly, the illumination light beam on the projection surface of the exit end face 1a on the sample S has a constant thickness in the optical axis direction (X direction) of the objective lens 11 and a constant width in the Y direction. In other words, the illumination device (light source 25, multimode fiber 1, illumination optical system 18) is configured so that the illumination light has a certain thickness in the optical axis direction of the objective lens 11 on the projection surface projected by the illumination optical system 18. Further, the illumination light can be irradiated.

  Therefore, according to the configuration of the illumination device (the light source 25, the multimode fiber 1, and the illumination optical system 18), the luminance in the optical axis direction of the objective lens in the region on the specimen used for imaging can be obtained with an inexpensive and simple configuration. Illumination light having a uniform distribution can be formed.

  Further, since the illumination optical system 18 is configured to be telecentric, the illumination light beam is symmetric with respect to the optical axis of the objective lens 11 in the illumination optical axis direction (Z direction). Therefore, as the illumination optical system that is not telecentric is irradiated with an asymmetric illumination light beam in the Z direction with the image position as a boundary, the illumination on the specimen S is biased, and the discoloration is greatly advanced partially. Can be suppressed.

  In addition, an area surrounded by the X direction, the Y direction, and the Z direction irradiated with the illumination light, and an area within the visual field range of the objective lens 11 is defined as an illumination area. That is, the illumination area is an area used for one-time imaging. At this time, according to the illuminating device of the present embodiment, the illumination light flux has a uniform luminance distribution in the XY section on the optical axis of the objective lens 11 which is the projection surface of the emission end face 1a. Since the illumination optical system 18 is telecentric, an illumination light beam is formed that maintains a certain degree of uniformity in the projection plane in the Z direction as compared with a light beam irradiated by a non-telecentric illumination optical system. It can be said. In particular, the uniformity on the projection plane is maintained as long as the visual field range of the objective lens 11 is reached. Therefore, the illumination distribution in the illumination area within the field of view of the objective lens 11 also has uniformity.

  The observation optical system 19 includes an objective lens 11, a first switching device 12, an emission filter 13, an imaging lens 14, a microlens array 15, a second switching device 16, and a camera 17. ing.

  The objective lens 11 takes in light (including fluorescence) from the specimen S. That is, the objective lens 11 captures light from the illumination area. The first switching device 12 is a switching device that switches and arranges the objective lens 11 arranged on the optical path of the observation optical system 19 from among a plurality of objective lenses. The first switching device 12 is, for example, a revolver.

  The emission filter 13 is a filter that separates unnecessary light (scattered light of illumination light, etc.) other than fluorescence from the specimen S. As the emission filter 13, a filter that transmits light having a certain wavelength or more including fluorescence is selected.

  The imaging lens 14 forms an image of the fluorescence that has entered through the objective lens 11 and the emission filter 13 onto a microlens array 15 that is disposed at a substantially focal position of the imaging lens 14.

  The microlens array 15 is disposed at a substantially focal position of the imaging lens 14. The microlens array 15 is a lens array in which a plurality of microlenses are arranged on the same plane (YZ plane). Therefore, in the illumination area, light from the positions of the different specimens S on the YZ plane is incident on different microlenses on the microlens array 15 and guided to the camera 17. The camera 17 captures light field data.

  The second switching device 16 is a switching device that switches and arranges the microlens array 15 disposed on the optical path of the observation optical system 19 from among a plurality of microlens arrays. The second switching device 16 is, for example, a turret.

  Thus, according to the observation optical system 19 in the light field microscope 10, information in the illumination area can be acquired by one imaging, and three-dimensional image data in the illumination area can be generated by image processing after imaging. .

  The control device 20 is a control computer for controlling each component of the light field microscope 10. A functional configuration of the control device 20 will be described with reference to the drawings. FIG. 4 is a diagram illustrating a functional configuration of the control device 20. The control device 20 includes an aperture control unit 21, a stage control unit 22, an objective lens switching unit 23, and a lens array switching unit 24.

  The diaphragm control unit 21 adjusts the opening widths of the field diaphragm 4 and the brightness diaphragm 6. The stage control unit 22 controls the movement of the position of the stage 9 at least in the X direction. A motor or the like (not shown) is used for moving the stage 9. In particular, when the specimen S is larger than the illumination area, it is desirable that the stage 9 is controlled to move in the Y and Z directions in order to capture the entire area of the specimen S. Images obtained at different positions by moving the stage 9 can be combined into one image after being imaged. The objective lens switching unit 23 controls the first switching device 12 (revolver or the like) and selects the objective lens 11 disposed on the optical path. The lens array switching unit 24 controls the second switching device 16 (turret or the like) and selects the microlens array 15 disposed on the optical path.

  As an example of the control of the control device 20, the field stop 4 is adjusted by the stop control unit 21 so that the aperture width is suitable for the objective lens to be used according to the switching of the objective lens 11 by the objective lens switching unit 23. . At this time, the aperture stop 6 may be adjusted as appropriate. Further, the switching of the microlens array 15 by the lens array switching unit 24 is assumed to be a situation in which different microlens arrays 15 are switched and installed on the optical path for one objective lens 11.

  According to the light field microscope 10 having the above configuration, as described above, the illumination device (the light source 25, the multimode fiber 1, and the illumination optical system 18) can be used in an area on the specimen (illumination area) used for imaging. The illumination light with uniform luminance distribution in the optical axis direction of the objective lens can be formed.

  In addition, by enabling illumination having a uniform luminance distribution in the illumination area as in the present invention, it is possible to perform good observation with a light field microscope. In the technical field of light field microscopes, the illumination area (including the X direction, Y direction, and Z direction) used for one-time imaging is in the direction of the optical axis of the objective lens compared to other microscope devices (such as a light sheet microscope). Large in (X-axis direction). For this reason, the nonuniformity of the luminance distribution in the illumination area has a great influence on the imaging, and the technique for making the luminance distribution of the section of the illumination light beam uniform is particularly effective in observation with a light field microscope.

  Hereinafter, the light field microscope 30 according to the second embodiment will be described. FIG. 5 is a diagram illustrating a configuration of the light field microscope 30. The light field microscope 30 is different from the light field microscope 10 in that it has a plurality of switchable illumination optical systems 31, a third switching device 32 for performing the switching, and a control device 33. Is the same.

  The plurality of illumination optical systems 31 are optical systems having different projection magnifications. The third switching device 32 is a switching device that switches the illumination optical system to be arranged from among the plurality of illumination optical systems 31. The third switching device 32 is, for example, a turret. In addition, the control device 33 has a new functional configuration for controlling the switching operation of the third switching device 32 and is different from the functional configuration of the control device 20 in that the diaphragm control unit 21 is not provided.

  In addition, any of the plurality of illumination optical systems 31 in the light field microscope 30 does not form an intermediate image in the illumination optical system, does not have a stop (a stop corresponding to the field stop 4 and the brightness stop 6), and has a core. This is an optical system in which an image of illumination light on the exit end face 1b of 1a is projected on the optical axis of the objective lens 11 as it is. Even with such a configuration, illumination light having a uniform luminance distribution can be formed on the specimen S.

  Further, since the light field microscope 30 has a configuration that does not form an intermediate image, the overall length of the illumination optical system can be suppressed as compared with the light field microscope 10, and thus the apparatus can be miniaturized.

  Hereinafter, the light field microscope 40 according to the third embodiment will be described with reference to the drawings. FIG. 6 is a diagram illustrating a configuration of the light field microscope 40. The light field microscope 40 includes a light source 25 (similar to the first embodiment), a multimode fiber 41, and an illumination optical system 51 as an illumination device, and a control device 60 instead of the control device 20. Although it differs from the light field microscope 10 in the point provided, it is the same about other points.

  FIG. 7 is a diagram illustrating a state in which the emission end face 41a of the multimode fiber 41 is viewed from the Z direction. The multimode fiber 41 includes a core 41b that is a rectangular core having a rectangular shape. The core 41b is a rectangular (square) core having a core size of 800 × 800 μm, and the injection NA of the core 41b is 0.1. Here, the core 41b of the multimode fiber 41 has a direction in which any two of the four sides forming the outer periphery are orthogonal to the optical axis of the objective lens 11 included in the observation optical system 19 (that is, the Y direction). It is arranged to face.

  The illumination optical system 51 includes lenses 42 and 43, cylindrical lenses 45, 47, 48 and 50, a field stop 44, and brightness stops 46 and 49. The cylindrical lenses 45, 47, 48, and 50 are referred to as first, second, third, and fourth cylindrical lenses, respectively. Each cylindrical lens is arranged in the order of the first, second, third, and fourth cylindrical lenses from the light source side.

  The lenses 42 and 43 relay the illumination light emitted from the multimode fiber 41 and form an intermediate image in the illumination optical system 51. Specifically, the lenses 42 and 43 enlarge the image of the illumination light on the emission end face 41a by a factor of 2 and project it on the intermediate image position. That is, a rectangular (square) image on the exit end face 1a having a size of 1600 × 1600 μm is projected at the intermediate image position. The lenses 42 and 43 are configured telecentric.

  The field stop 44 is a stop (first stop) disposed at or near the intermediate image position formed by the lenses 42 and 43. FIG. 8 is a diagram illustrating a state in which the field stop 4 is viewed from the Z direction. The field stop 44 is composed of four stop plates (stop plates 44a, 44b, 44c, 44d), and forms a rectangular shape on the outer periphery of the region through which the illumination light of the field stop 44 passes. The field stop 44 has the same configuration as that of the field stop 4, the aperture width can be arbitrarily adjusted, and the same applies to control by the control device (here, the control device 60).

  Here, the light flux that has passed through the field stop 44 receives different contributions in the illumination optical system 51 on the XZ plane and on the YZ plane as shown in FIG.

  A configuration in the illumination optical system 51 that contributes on the XZ plane will be described with reference to the upper portion of the illumination optical system 51 in FIG. The cylindrical lenses 47 and 50 (second and fourth cylindrical lenses) are cylindrical lenses having power in the optical axis direction (X direction) of the objective lens, and an intermediate image formed by the lenses 42 and 43 is reduced on the sample S. Reduced projection at a magnification of 0.5. Further, the cylindrical lenses 47 and 50 are configured telecentric in the optical axis direction (X direction) of the objective lens.

  The aperture stop 49 is a stop that contributes only in the X direction, and is arranged at the pupil position of the cylindrical lens 50. FIG. 9 is a diagram illustrating a state in which the aperture stop 49 is viewed from the Z direction. The brightness stop 49 is composed of two stop plates (stop plates 49a and 49b), and the thickness of the light beam in the X direction is changed by changing the width of the stop plates 49a and 49b. Note that the brightness stop 49 is configured so that the brightness stop 6 in the first embodiment acts only in the X direction, that is, the function corresponds to the second stop. The brightness stop 49 is controlled by the control device 60.

  The components in the illumination optical system 51 that contribute on the YZ plane are the remaining cylindrical lenses 45 and 48 (first and third cylindrical lenses) and the aperture stop 46. Cylindrical lenses 45 and 48 (first and third cylindrical lenses) are cylindrical lenses having power in a direction (Y direction) orthogonal to the optical axis of the objective lens, and an intermediate image formed by the lenses 42 and 43 is obtained as a sample S. The image is enlarged and projected at an enlargement magnification of 4 times. That is, the illumination optical system 51 has a larger projection magnification in the direction (Y direction) orthogonal to the optical axis of the objective lens 11 than in the optical axis direction (X direction) of the objective lens 11. Further, the cylindrical lenses 45 and 48 are configured telecentric in a direction (Y direction) orthogonal to the optical axis of the objective lens.

  The brightness stop 46 is a stop that contributes only in the Y direction, and is arranged by changing the direction of the stop having the same configuration as the brightness stop 49. That is, the aperture stop 46 changes the width of the light beam in the Y direction. The brightness stop 46 is disposed at the pupil position of the cylindrical lens 48. The brightness stop 46 is also controlled by the control device 60.

  In the configuration described above, the illumination optical system 51 forms and irradiates a light beam having a rectangular cross section of 800 × 6400 μm on the XY plane on the sample S on the optical axis of the objective lens 11. As described above, the rectangular cross section of the light beam can be adjusted to an arbitrary rectangular cross section by the field stop 40.

  FIG. 10 is a diagram illustrating a functional configuration of a control device 60 that is a control computer for controlling each configuration of the light field microscope 40. The control device 60 includes an aperture control unit 61, a stage control unit 62, an objective lens switching unit 63, and a lens array switching unit 64. The aperture control unit 61 is different from the aperture control unit 21 in that it controls a plurality of brightness apertures (brightness apertures 46 and 49). The stage control unit 62, the objective lens switching unit 63, and the lens array switching unit 64 have the same functions as the stage control unit 22, the objective lens switching unit 23, and the lens array switching unit 24 of the control device 20. Have.

  As described above, the illumination optical system 51 can be configured to have different projection magnifications in the X direction and the Y direction. In particular, in this configuration, an aperture stop that contributes to each of the X direction and the Y direction is independently installed, and by appropriately adjusting these, it is possible to suppress the difference in the emission NA between the X direction and the Y direction. Is possible. According to this configuration, the width and thickness of the rectangular cross section of the light beam can be adjusted more widely.

  Further, the core size of the core 41b and the projection magnification of each lens may be designed by changing values according to the target observation.

  In this configuration, the illumination optical system 51 is configured to be telecentric in the optical axis direction (X direction) of the objective lens 11 or in the direction orthogonal to the optical axis of the objective lens 11 (Y direction). Yes. Therefore, this configuration can also provide an illumination optical system configured telecentrically in both the X direction and the Y direction as in the light field microscope 10. Further, either the optical axis direction (X direction) of the objective lens 11 or the direction (Y direction) orthogonal to the optical axis of the objective lens 11 can be configured to be telecentric.

  Hereinafter, a light field microscope 70 according to a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 11 is a diagram illustrating a configuration of the light field microscope 70.

  The light field microscope 70 is different from the light field microscope 10 in that it has a multimode fiber 71 instead of the multimode fiber 1, but is otherwise the same as the light field microscope 10.

  FIG. 12 is a diagram illustrating a state in which the emission end surface 71a of the multimode fiber 71 is viewed from the illumination optical axis direction (Z direction). The multimode fiber 71 has a core 71b which is a core having a circular cross section.

  Even in such a configuration, the illumination optical system 18 includes the field stop 4 as the first stop as a configuration, so that the illumination light beam becomes a rectangular light beam in the XY section at the intermediate image position, and the objective lens Illumination light having a certain thickness in the optical axis direction (X direction) of the lens 11 and a certain width in the Y direction can be irradiated. That is, in the fourth embodiment, the field stop 4 as the first stop has a role of giving a certain thickness in the X-axis direction to the illumination light beam on the projection plane of the XY cross section on the sample S. Yes.

  FIG. 13 is a diagram illustrating an example of another configuration of the field stop 4, and is a diagram illustrating a state viewed from the Z direction. The field stop 4 may have a configuration having only the stop plates 4a and 4b, that is, a configuration in which the thickness in the X direction is constant and the shape of the light beam is not changed in the Y direction. For example, if the illumination light beam is sufficiently larger than the visual field range of the objective lens 11, the light beam does not have to have a constant width in the Y direction. In that case, the light beam outside the field of view of the objective lens 11 does not contribute to imaging. In this case, the aperture stop 6 is a circular or circular approximate stop corresponding to the pupil shape.

  Further, in the present embodiment, the means for narrowing the illumination light beam such as the field stop 4 is not limited to the configuration arranged at the intermediate image position formed by the lenses 2 and 3. For example, even if the multimode fiber 71 has a core 71b that is a circular core by installing a rectangular aperture on the emission end face 71a, the multimode fiber 1 of the first embodiment is similar to the multimode fiber 1 of the first embodiment. A light beam having a rectangular cross section can be formed on the exit end face.

  As described above, the core shape of the multimode fiber used in the present invention is not limited. Accordingly, illumination light having a uniform luminance distribution can be formed on the specimen S also by the light field microscope 70.

  The embodiments described above are specific examples for facilitating the understanding of the invention, and the present invention is not limited to these embodiments. The light field microscope described above can be variously modified and changed without departing from the scope of the present invention described in the claims.

10, 30, 40, 70 Light field microscope 1, 41, 71 Multimode fiber 1a, 41a, 71a Outgoing end face 1b, 41b, 71b Core 2, 3, 5, 7, 42, 43 Lens 4, 44 Field stop 6, 46, 49 Brightness stops 4a, 4b, 4c, 4d, 44a, 44b,
44c, 44d, 49a, 49b Aperture plate 8 Container 9 Stage 11 Objective lens 12 First switching device 13 Emission filter 14 Imaging lens 15 Micro lens array 16 Second switching device 17 Camera 18, 51 Illumination optical system 19 Observation optics System 20, 33, 60 Control device 25 Light source 31 Multiple illumination optical system 32 Third switching device 45, 47, 48, 50 Cylindrical lens S Sample

Claims (13)

An objective lens that captures light from the specimen;
An illumination device that irradiates the specimen with illumination light from a direction orthogonal to the optical axis of the objective lens,
The lighting device includes:
A light source for emitting the illumination light;
A multi-mode fiber that guides the illumination light from the light source and emits it from the exit end face;
An illumination optical system that projects an image of the exit end face onto the optical axis of the objective lens,
The illumination device irradiates the illumination light so that the illumination light has a certain thickness in the optical axis direction of the objective lens on a projection surface projected by the illumination optical system. microscope. The light field microscope according to claim 1,
The light field microscope according to claim 1, wherein the illumination optical system includes a first diaphragm that makes the illumination range constant in a direction of an optical axis of the objective lens. The light field microscope according to claim 2,
The illumination optical system forms an intermediate image;
The light field microscope, wherein the illumination optical system has the first stop at or near the intermediate image position. The light field microscope according to claim 2 or claim 3,
The first diaphragm is a diaphragm that forms a rectangular shape on an outer periphery of a region through which the illumination light of the first diaphragm passes, and two opposing sides of the four sides forming the rectangular shape are the A light field microscope characterized by being orthogonal to the optical axis of an objective lens. The light field microscope according to any one of claims 2 to 4,
The light field microscope, wherein the illumination optical system has a second stop at an exit pupil position in the illumination optical system. The light field microscope according to claim 5,
The light field microscope, wherein the first diaphragm and the second diaphragm are each configured to be variable in degree of diaphragm, or configured to be switchable with other diaphragms having different sizes. The light field microscope according to any one of claims 1 to 6,
The core of the multimode fiber is a rectangular core having a rectangular shape, and two opposing sides of the four sides forming the outer periphery of the rectangular core are orthogonal to the optical axis of the objective lens at the emission end face. Light field microscope characterized by. The light field microscope according to claim 7,
The length of each side of the rectangular core perpendicular to the optical axis of the objective lens is longer than the length of each side of the rectangular core parallel to the optical axis of the objective lens. Light field microscope. The light field microscope according to any one of claims 1 to 8,
The illumination optical system is configured to be telecentric with respect to either or both of the optical axis direction of the objective lens and the direction orthogonal to the optical axis of the objective lens. . The light field microscope according to any one of claims 1 to 9,
The light field microscope, wherein the illumination optical system has different projection magnifications in an optical axis direction of the objective lens and a direction orthogonal to the optical axis of the objective lens. The light field microscope according to claim 10,
The light field microscope, wherein the illumination optical system has a larger projection magnification in a direction orthogonal to the optical axis of the objective lens than in the optical axis direction of the objective lens. The light field microscope according to claim 10 or claim 11,
The illumination optical system includes first and third cylindrical lenses having power in a direction orthogonal to the optical axis of the objective lens, and second and fourth cylindrical lenses having power in the optical axis direction of the objective lens. Have
The first to fourth cylindrical lenses are arranged in the order of the first, second, third, and fourth cylindrical lenses from the emission end face side of the multimode fiber. Light field microscope. The light field microscope according to any one of claims 1 to 12,
The illumination optical system is configured to be switchable with another illumination optical system having a different projection magnification.