Scanning optical system, microscope optical system, and microscope device

Abstract

This scanning optical system is provided between a scanning mechanism which scans light and emits scanning light, and an objective optical system which receives and emits the scanning light toward a sample and simultaneously receives light from the sample and forms a primary image plane at a position conjugate with the sample, and is configured to receive the scanning light and emit the scanning light toward the objective optical system. The scanning optical system has a plurality of lens components and has positive refractive power as a whole. At least one of the plurality of lens components is a movable lens component that is movable along the optical axis.

Description

Scanning optical system, microscope optical system, and microscope apparatus

[0001] The present disclosure relates to a scanning optical system, a microscope optical system, and a microscope apparatus.

[0002] An example of a scanning confocal microscope is described in US Pat. No. 6,244,999.

[0003] US Patent Application Publication No. 2007 / 0153367

[0004] The scanning optical system of the present disclosure is provided between a scanning mechanism that scans light and emits the scanning light, and an objective optical system that transmits the scanning light and emits it toward a sample, and receives light from the sample and forms a primary image plane at a position conjugate with the sample, and receives the scanning light and emits it toward the objective optical system. The scanning optical system has multiple lens components and has positive refractive power as a whole. At least one of the multiple lens components is a movable lens component that can move along an optical axis.

[0005] FIG. 1 is a schematic diagram of a microscope apparatus equipped with a scanning optical system. FIG. 2 is a cross-sectional view of the scanning optical system of the first embodiment. FIG. 3A is a diagram showing various aberrations of the scanning optical system of the first embodiment in a first state. FIG. 3B is a diagram showing various aberrations of the scanning optical system of the first embodiment in a second state. FIG. 3C is a diagram showing various aberrations of the scanning optical system of the first embodiment in a third state. FIG. 3D is a diagram showing various aberrations of the scanning optical system of the first embodiment in a fourth state. FIG. 3E is a diagram showing various aberrations of the scanning optical system of the first embodiment in a fifth state. FIG. 4 is a cross-sectional view of the scanning optical system of the second embodiment. FIG. 5A is a diagram showing various aberrations of the scanning optical system of the second embodiment in a first state. FIG. 5B is a diagram showing various aberrations of the scanning optical system of the second embodiment in a second state. FIG. 5C is a diagram showing various aberrations of the scanning optical system of the second embodiment in a third state. FIG. 5D is a diagram showing various aberrations of the scanning optical system of the second embodiment in a fourth state. FIG. 5E is a diagram showing various aberrations of the scanning optical system of the second embodiment in a fifth state. FIG. 6 is a cross-sectional view of the scanning optical system of the third embodiment. FIG. 7A is a diagram showing various aberrations of the scanning optical system of the third embodiment in a first state. FIG. 7B is a diagram showing various aberrations of the scanning optical system of the third embodiment in a second state. FIG. 7C is a diagram showing various aberrations of the scanning optical system of the third embodiment in a third state. FIG. 7D is a diagram showing various aberrations of the scanning optical system of the third embodiment in a fourth state. FIG. 7E is a diagram showing various aberrations of the scanning optical system of the third embodiment in a fifth state. FIG. 8 is a cross-sectional view of the scanning optical system of the fourth embodiment. FIG. 9A is a diagram showing various aberrations of the scanning optical system of the fourth embodiment in a first state. FIG. 9B is a diagram showing various aberrations of the scanning optical system of the fourth embodiment in a second state. FIG. 9C is a diagram showing various aberrations of the scanning optical system of the fourth embodiment in a third state. FIG. 9D is a diagram showing various aberrations of the scanning optical system of the fourth embodiment in a fourth state. FIG. 9E is a diagram showing various aberrations of the scanning optical system of the fourth embodiment in a fifth state. FIG. 10 is a cross-sectional view of an imaging optical system that can be used with the scanning optical system of the fourth embodiment. FIG. 11 is a cross-sectional view of an objective optical system that can be used with the scanning optical system of the fourth embodiment.

[0006] A scanning optical system, a microscope optical system, and a microscope apparatus according to embodiments of the present disclosure will be described below. The microscope apparatus according to the present embodiments is a scanning confocal microscope that focuses light onto a sample in a spot and scans the spot.

[0007] 1 is a schematic diagram of a microscope MS including a scanning optical system SOS, which includes a control unit CU, a light source LS, an illumination optical system LOS, a detector DM, a detection optical system DOS, a light branching member BS, a scanning mechanism SM, the scanning optical system SOS, an imaging optical system TOS, and an objective optical system OOS.

[0008] The scanning optical system SOS, the scanning mechanism SM, and the objective optical system OOS can be collectively referred to as a microscope optical system. The microscope optical system may further include at least one of an illumination optical system LOS, a detection optical system DOS, a light branching member BS, and an imaging optical system TOS.

[0009] Illumination light IL generated by the light source LS is irradiated onto the sample SA via the illumination optical system LOS, the light branching member BS, the scanning mechanism SM, the scanning optical system SOS, the imaging optical system TOS, and the objective optical system OOS. Return light RL generated based on the illumination of the illumination light IL onto the sample SA is emitted to the detector DM via the objective optical system OOS, the imaging optical system TOS, the scanning optical system SOS, the scanning mechanism SM, the light branching member BS, and the detection optical system DOS. The return light RL may be fluorescence excited by the illumination of the illumination light IL. In this case, the illumination light IL can also be referred to as excitation light. The detector DM outputs detection information based on the illumination of the return light RL.

[0010] The light source LS generates light as the irradiating light IL under the control of the control unit CU. The light source LS may generate visible light (for example, at least one of C-line (wavelength 656.3 nm), d-line (wavelength 587.6 nm), F-line (wavelength 486.1 nm), g-line (wavelength 435.8 nm), and h-line (wavelength 404.7 nm)), or may generate invisible light (for example, infrared light of 1300 nm). The light source LS may be capable of changing the wavelength of the generated light under the control of the control unit CU. The light generated by the light source LS may be laser light. In this case, the light source LS may be a laser light source (not shown, for example, a semiconductor laser such as a laser diode (LD), a fiber laser, a CO ２The light source LS may include at least one of a laser, a YAG laser, and an excimer laser. The light source LS may generate ultrashort pulsed light. The illumination light IL generated by the light source LS is incident on the illumination optical system LOS.

[0011] The illumination optical system LOS converts the incident illumination light IL into parallel light and emits it toward the light branching member BS. The illumination optical system LOS may include an aperture stop (not shown). The illumination optical system LOS may also convert the incident illumination light IL into linearly polarized light. To achieve this, the illumination optical system LOS may include, for example, a polarizing plate.

[0012] The light branching member BS has a branching surface that reflects at least a portion of the incident light and transmits at least a portion of the remaining light. The light branching member BS may be a dichroic mirror whose reflectance below a predetermined wavelength is lower than its reflectance at wavelengths equal to or greater than the predetermined wavelength. The light branching member BS may also be a polarizing beam splitter that separates the incident light into S-polarized light and P-polarized light. The light branching member BS emits at least a portion of the incident illumination light IL toward the scanning mechanism SM. The light branching member BS also emits at least a portion of the return light RL incident from the scanning mechanism SM toward the detection optical system DOS. The light branching member BS may be disposed between the scanning optical system SOS and the imaging optical system TOS. In this case, the scanning mechanism SM is disposed at one end of the light branching member BS, and the detection optical system DOS is disposed at the other end.

[0013] The scanning mechanism SM changes the irradiation direction of the incident illumination light IL based on the control of the control unit CU and emits at least a portion of it toward the scanning optical system. It can also be said that the scanning mechanism SM scans the illumination light IL and emits scanning light. The scanning mechanism SM is disposed near a pupil conjugate plane CP conjugate to the exit pupil of the objective optical system OOS. The scanning mechanism SM is configured with, for example, a galvanometer mirror or a resonant mirror. It can also be said that the scanning mechanism SM changes the focusing position of the illumination light IL on the sample SA by deflecting the illumination light IL and scans the sample SA with the illumination light IL. The scanning mechanism SM also emits at least a portion of the return light RL incident from the scanning optical system SOS toward the light branching member BS.

[0014] The scanning optical system SOS is provided between the scanning mechanism SM and the objective optical system OOS. In the example of FIG. 1 , an imaging optical system TOS is further provided between the scanning optical system SOS and the objective optical system OOS, and the scanning optical system SOS emits at least a portion of the scanning light incident from the scanning mechanism SM toward the imaging optical system TOS. The focal position of the scanning optical system SOS is located at a primary image plane IP conjugate with the sample SA. The primary image plane IP conjugate with the sample SA can also be referred to as a primary image plane formed by the objective optical system OOS, which receives the return light RL from the sample SA. The scanning optical system SOS has multiple lens components (single lenses or cemented lenses). The scanning optical system SOS has a positive refractive power as a whole. At least one of the multiple lens components of the scanning optical system SOS is a movable lens component movable along the optical axis. A scanning optical system SOS having such a configuration can appropriately correct chromatic aberration of magnification occurring in at least one of the imaging optical system TOS and the objective optical system OOS over a wide wavelength range. The scanning optical system SOS may move the movable lens component under the control of the control unit CU.

[0015] The imaging optical system TOS is provided between the scanning optical system SOS and the objective optical system. The imaging optical system TOS converts the illumination light IL incident from the scanning optical system SOS into a parallel light beam and emits at least a portion of the parallel light beam toward the objective optical system OOS. The imaging optical system TOS also forms an image of the return light RL of the parallel light beam incident from the objective optical system OOS on a primary image plane IP.

[0016] The objective optical system OOS is disposed between the imaging optical system TOS and the sample SA. The objective optical system OOS irradiates at least a portion of the parallel beam of illumination light IL incident from the imaging optical system TOS onto the sample SA. The objective optical system OOS also receives return light RL based on the irradiation of the illumination light IL, converts it into a parallel beam of light, and emits at least a portion of it toward the imaging optical system TOS. The objective optical system OOS may be an optical system that is telecentric on the image side. In this case, the exit pupil plane of the objective optical system OOS is the back focal plane of the objective optical system OOS.

[0017] The space between the objective optical system OOS and the sample SA may be filled with a liquid (not shown), such as water, oil, or glycerin. Also, a cover glass (not shown) may be provided between the objective optical system OOS and the sample SA. In this case, the objective optical system OOS may be configured to include the cover glass.

[0018] The detection optical system DOS emits the return light RL incident from the light branching member BS toward the detector DM. The detection optical system DOS may also emit light that has passed through a pinhole positioned conjugate with the sample SA toward the detector DM. A microscope having such a detection optical system DOS can also be called a confocal microscope. Furthermore, the detection optical system DOS may also emit the return light RL generated by multiphoton excitation of the sample SA by the illumination light IL based on the ultrashort pulse light generated by the light source LS toward the detector DM. A microscope having such a detection optical system DOS can also be called a multiphoton excitation microscope or a two-photon excitation microscope. Furthermore, the detection optical system DOS may have an aperture stop (not shown).

[0019] The detector DM generates a detection signal according to the incident return light RL. For example, the detector DM has a light-receiving surface on which a light-receiving element is arranged. The detection optical system DOS forms an image of the return light RL on the light-receiving surface. The detection signal is output to the control unit CU.

[0020] The control unit CU is communicatively connected to the light source LS, the scanning mechanism SM, the scanning optical system SOS, and the detector DM. The control unit CU may be, for example, a computer device capable of executing a predetermined computer program. The control unit CU transmits control signals to the light source LS, the scanning mechanism SM, and the scanning optical system SOS to control the operation of these devices. For example, the control unit CU may transmit a control signal to the light source LS to generate light of a predetermined wavelength, and a control signal to the scanning optical system SOS to move a movable lens component so as to achieve particularly good correction of the chromatic aberration of magnification of the light of that wavelength. The control unit CU also performs image processing based on the detection signal received from the detector DM to generate an image corresponding to the sample SA. The generated image may be displayed, for example, on a display (not shown).

[0021] The scanning optical system SOS of this embodiment preferably satisfies the following condition: (1) 0.30<fO / fI<1.20, where fO: focal length of the scanning optical system SOS when the movable lens component arranged closest to the sample SA among the at least one movable lens component moves most toward the sample SA, and fI: focal length of the scanning optical system SOS when the movable lens component arranged closest to the sample SA among the at least one movable lens component moves most toward the scanning mechanism SM.

[0022] Conditional expression (1) defines the ratio of the focal lengths of the scanning optical system SOS when the movable lens component arranged closest to the sample SA among at least one movable lens component is moved closest to the sample SA to when it is moved closest to the scanning mechanism SM. By satisfying conditional expression (1), the scanning optical system SOS of this embodiment can suppress fluctuations in image size accompanying movement of the movable lens component. If the image size varies significantly with movement of the movable lens component, when multiple light beams of different wavelengths are used and the movable lens component is moved to positions corresponding to each wavelength to superimpose the images obtained, the images will not be properly superimposed because the image sizes for each wavelength will be different.

[0023] In the scanning optical system SOS of this embodiment, if the value of conditional expression (1) exceeds the upper limit, the focal length of the scanning optical system SOS becomes too long when the movable lens component positioned closest to the sample SA among the movable lens components moves furthest toward the sample SA, and the image obtained becomes too large compared to when the movable lens component positioned closest to the sample SA moves furthest toward the scanning mechanism SM.

[0024] In the scanning optical system SOS of this embodiment, the upper limit value of conditional expression (1) is set to 1.20, thereby making it possible to further ensure the effects of this embodiment. In order to further ensure the effects of this embodiment, it is preferable to set the upper limit value of conditional expression (1) to 1.15, 1.10, or even 1.05.

[0025] Furthermore, in the scanning optical system SOS of this embodiment, if the value of conditional expression (1) falls below the lower limit, the focal length of the scanning optical system SOS becomes too long when the movable lens component positioned closest to the sample SA among the movable lens components moves furthest toward the scanning mechanism SM, and the image obtained becomes too large compared to when the movable lens component positioned closest to the sample SA moves furthest toward the sample SA.

[0026] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (1) to 0.30. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (1) to 0.40, 0.50, 0.60, 0.70, 0.80, 0.85, 0.90, or even 0.95.

[0027] In the scanning optical system SOS of this embodiment, it is preferable that at least two of the plurality of lens components are movable lens components.

[0028] With this configuration, the scanning optical system SOS of this embodiment can effectively correct various aberrations such as axial chromatic aberration and coma aberration over the entire movable range of the movable lens components.

[0029] In the scanning optical system SOS of this embodiment, the multiple lens components consist of four lens components including two movable lens components and two lens components other than the movable lens components, and it is preferable that the four lens components have positive, negative, negative, and positive refractive powers, in that order from the scanning mechanism SM side.

[0030] With this configuration, the scanning optical system SOS of this embodiment can effectively correct various aberrations such as astigmatism and coma.

[0031] In the scanning optical system SOS of this embodiment, the multiple lens components consist of four lens components including two movable lens components and two lens components other than the movable lens components, and it is preferable that the two movable lens components are arranged second and third, respectively, from the scanning mechanism SM side.

[0032] With this configuration, the scanning optical system SOS of this embodiment can effectively correct various aberrations such as astigmatism and coma.

[0033] The scanning optical system SOS of this embodiment preferably satisfies the following condition (2): 5.00 < |fM1| / fO < 100.00, where fM1 is the focal length of the movable lens component arranged closest to the sample SA among the at least one movable lens component, and fO is the focal length of the scanning optical system SOS when the movable lens component arranged closest to the sample SA among the at least one movable lens component has moved most towards the sample SA.

[0034] Conditional expression (2) defines the ratio between the focal length of the movable lens component that is arranged closest to the sample SA among the at least one movable lens component and the focal length of the scanning optical system SOS when the movable lens component that is arranged closest to the sample SA among the at least one movable lens component moves closest to the sample SA. By satisfying conditional expression (2), the scanning optical system SOS of this embodiment can suppress focal length fluctuations while appropriately correcting various aberrations such as chromatic aberration of magnification by moving the movable lens component.

[0035] In the scanning optical system SOS of this embodiment, if the value of conditional expression (2) exceeds the upper limit, it becomes difficult to obtain a sufficient amount of correction for chromatic aberration of magnification due to the movement of the movable lens component.

[0036] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit value of conditional expression (2) to 100.00. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of conditional expression (2) to 90.00, 80.00, 70.00, or even 60.00.

[0037] Furthermore, in the scanning optical system SOS of this embodiment, if the value of conditional expression (2) is below the lower limit, the changes in various aberrations, such as axial chromatic aberration and astigmatism, due to the movement of the movable lens components will be too large, and the changes in focal length due to the movement of the movable lens components will be too large, making it impossible to properly superimpose images obtained using multiple light beams with different wavelengths.

[0038] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (2) to 5.00. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (2) to 5.50, 6.00, 6.50, 7.00, or even 7.50.

[0039] The scanning optical system SOS of this embodiment preferably satisfies the following conditional expression (3): 0.90 < βM1O / βM1I < 1.10, where βM1O: the lateral magnification of the movable lens component arranged closest to the sample SA when the movable lens component arranged closest to the sample SA among the at least one movable lens component moves closest to the sample SA, and βM1I: the lateral magnification of the movable lens component arranged closest to the sample SA when the movable lens component arranged closest to the sample SA among the at least one movable lens component moves closest to the scanning mechanism SM.

[0040] Conditional expression (3) defines the ratio of the lateral magnification of the movable lens component arranged closest to the sample SA among at least one movable lens component when the movable lens component moves closest to the sample SA to when the movable lens component moves closest to the scanning mechanism SM. By satisfying conditional expression (3), the scanning optical system SOS of this embodiment can suppress fluctuations in the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS that occur due to movement of the movable lens component.

[0041] In the scanning optical system SOS of this embodiment, if the value of conditional expression (3) exceeds the upper limit, the focusing position of the scanning optical system SOS is likely to shift toward the sample SA when the movable lens component arranged closest to the sample SA moves closest to the sample SA. As a result, the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is likely to be disrupted when the movable lens component arranged closest to the sample SA moves closest to the sample SA. When the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is disrupted, the focusing plane on the sample SA shifts on the optical axis, resulting in defocusing.

[0042] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit value of conditional expression (3) to 1.10. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of conditional expression (3) to 1.09, 1.08, 1.07, 1.06, or even 1.05.

[0043] Furthermore, in the scanning optical system SOS of this embodiment, if the value of conditional expression (3) falls below the lower limit, the focusing position of the scanning optical system SOS is likely to shift toward the scanning mechanism SM when the movable lens component arranged closest to the sample SA moves closest to the sample SA. As a result, the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is likely to be disrupted when the movable lens component arranged closest to the sample SA moves closest to the sample SA. When the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is disrupted, the focusing plane on the sample SA shifts on the optical axis, resulting in defocusing.

[0044] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (3) to 0.90. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (3) to 0.91, 0.92, 0.93, 0.94, or even 0.95.

[0045] It is preferable that the scanning optical system SOS of this embodiment satisfies the following condition (4): −4.00<βM1O<1.35 where βM1O is the lateral magnification of the movable lens component arranged closest to the sample SA when the movable lens component arranged closest to the sample SA among at least one movable lens component moves closest to the sample SA.

[0046] Conditional expression (4) defines the lateral magnification of the movable lens component that is closest to the sample SA when the movable lens component that is closest to the sample SA among the at least one movable lens component moves closest to the sample SA. By satisfying conditional expression (4), the scanning optical system SOS of this embodiment can suppress fluctuations in the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS when the movable lens component that is closest to the sample SA moves closest to the sample SA.

[0047] In the scanning optical system SOS of this embodiment, if the value of conditional expression (4) exceeds the upper limit, the focusing position of the scanning optical system SOS is likely to shift toward the sample SA when the movable lens component arranged closest to the sample SA moves closest to the sample SA. As a result, the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is likely to be disrupted when the movable lens component arranged closest to the sample SA moves closest to the sample SA. When the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is disrupted, the focusing plane on the sample SA shifts on the optical axis, resulting in defocusing.

[0048] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (4) to 1.35. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (4) to 1.30, 1.25, or even 1.20.

[0049] Furthermore, in the scanning optical system SOS of this embodiment, if the value of conditional expression (4) falls below the lower limit, the focusing position of the scanning optical system SOS is likely to shift toward the scanning mechanism SM when the movable lens component arranged closest to the sample SA moves closest to the sample SA. As a result, the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is likely to be disrupted when the movable lens component arranged closest to the sample SA moves closest to the sample SA. When the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is disrupted, the focusing plane on the sample SA shifts on the optical axis, resulting in defocusing.

[0050] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (4) to -4.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (4) to -3.75, -3.50, -3.25, -3.00, or even -2.80.

[0051] It is preferable that the scanning optical system SOS of this embodiment satisfies the following conditional expression (5): −5.00<βM1I<1.35, where βM1I is the lateral magnification of the movable lens component that is arranged closest to the sample SA when the movable lens component that is arranged closest to the sample SA among at least one movable lens component moves closest to the scanning mechanism SM.

[0052] Conditional expression (5) defines the lateral magnification of the movable lens component that is closest to the sample SA when the movable lens component that is closest to the sample SA among the at least one movable lens component moves closest to the scanning mechanism SM. By satisfying conditional expression (5), the scanning optical system SOS of this embodiment can suppress fluctuations in the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS when the movable lens component that is closest to the sample SA moves closest to the scanning mechanism SM.

[0053] In the scanning optical system SOS of this embodiment, if the value of conditional expression (5) exceeds the upper limit, the focusing position of the scanning optical system SOS is likely to shift toward the sample SA when the movable lens component arranged closest to the sample SA moves closest to the scanning mechanism SM. As a result, the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is likely to be disrupted when the movable lens component arranged closest to the sample SA moves closest to the scanning mechanism SM. When the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is disrupted, the focusing plane on the sample SA shifts on the optical axis, resulting in defocusing.

[0054] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (5) to 1.35. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (5) to 1.30, 1.25, or even 1.20.

[0055] Furthermore, in the scanning optical system SOS of this embodiment, if the value of conditional expression (5) falls below the lower limit, the focusing position of the scanning optical system SOS is likely to shift toward the scanning mechanism SM when the movable lens component arranged closest to the sample SA moves closest to the scanning mechanism SM. As a result, the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is likely to be disrupted when the movable lens component arranged closest to the sample SA moves closest to the scanning mechanism SM. When the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is disrupted, the focusing plane on the sample SA shifts on the optical axis, resulting in defocusing.

[0056] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (5) to -5.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (5) to -4.50, -4.00, -3.50, or even -3.00.

[0057] It is preferable that the scanning optical system SOS of this embodiment has a first positive lens having positive refractive power and satisfies both of the following conditional expressions: (6) 0.000 < θgFP1 - (0.6438 - 0.00172 × vdP1) < 0.050 (7) 15.00 < vdP1 < 60.00 where, θgFP1: partial dispersion ratio of the first positive lens, which is expressed by the following expression using the refractive index ngP1 for the g-line, the refractive index nFP1 for the F-line, and the refractive index nCP1 for the C-line of the first positive lens: θgFP1 = (ngP1 - nFP1) / (nFP1 - nCP1) vdP1: Abbe number of the first positive lens

[0058] Conditional expression (6) defines the partial dispersion ratio and Abbe number of the first positive lens, and conditional expression (7) defines the Abbe number of the first positive lens. By having a first positive lens that satisfies both conditional expressions (6) and (7), the scanning optical system SOS of this embodiment can appropriately correct axial chromatic aberration in a wide wavelength range, set the Petzval sum to an appropriate value, and irradiate the sample SA with a sufficient amount of illumination light IL.

[0059] Lenses for which the value of conditional expression (6) exceeds the upper limit generally have a low refractive index, making it difficult to obtain an appropriate Petzval sum. Furthermore, such lenses generally have large second-order dispersion, which results in overcorrection of axial chromatic aberration and lateral chromatic aberration in a wide wavelength range.

[0060] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit value of conditional expression (6) to 0.050. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of conditional expression (6) to 0.045, 0.040, 0.035, 0.030, or even 0.020.

[0061] Furthermore, lenses for which the value of conditional expression (6) is below the lower limit generally have low transmittance, resulting in a dark image of the return light RL at the detector DM. Increasing the amount of illumination light IL generated by the light source LS to brighten the image undesirably increases phototoxicity to the sample SA. Furthermore, such lenses generally have small second-order dispersion, resulting in insufficient correction of axial chromatic aberration and lateral chromatic aberration over a wide wavelength range.

[0062] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (6) to 0.000. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (6) to 0.001, 0.002, 0.003, or even 0.004.

[0063] In the scanning optical system SOS of this embodiment, if the value of conditional expression (7) in the first positive lens exceeds the upper limit, axial chromatic aberration in a wide wavelength range is overcorrected.

[0064] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit value of conditional expression (7) to 60.00. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of conditional expression (7) to 58.00, 55.00, 52.00, 48.00, 44.00, or even 40.00.

[0065] In the scanning optical system SOS of this embodiment, if the value of conditional expression (7) in the first positive lens exceeds the lower limit, axial chromatic aberration in a wide wavelength range will be overcorrected.

[0066] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (7) to 15.00. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (7) to 17.50, 20.00, 22.50, 25.00, 27.00, 29.00, 30.00, or even 35.00.

[0067] It is preferable that the scanning optical system SOS of this embodiment satisfies the following conditional expression (8): 0.20<Σ(nd×d / νd)<1.50, where Σ(nd×d / νd) is the sum of the refractive index×center thickness / Abbe number of the lenses constituting each of the plurality of lens components.

[0068] Conditional expression (8) defines the sum of the refractive index×center thickness / Abbe number for the lenses that make up each of the plurality of lens components.

[0069] In multiphoton excitation microscopes, it is preferable to use optical pulses with extremely narrow pulse widths and sharp waveforms as excitation light in order to efficiently generate multiphoton excitation. However, when an optical pulse propagates through a medium (e.g., a lens) with group velocity dispersion (GVD), the pulse width (time width) of the optical pulse widens and the waveform changes. As the group delay dispersion (GDD), which is the group velocity dispersion multiplied by the thickness of the medium (e.g., the central thickness of the lens), increases, the pulse width of the optical pulse widens, and the excitation efficiency of multiphoton excitation decreases.

[0070] By satisfying conditional expression (8), the scanning optical system SOS of this embodiment can suppress group delay dispersion, increase the efficiency of multiphoton excitation, and appropriately correct various aberrations including off-axis astigmatism.

[0071] In the scanning optical system SOS of this embodiment, if the value of conditional expression (8) exceeds the upper limit, the group delay dispersion increases, and the excitation light efficiency of multiphoton excitation decreases.

[0072] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit value of conditional expression (8) to 1.50. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of conditional expression (8) to 1.40, 1.30, 1.20, 1.10, 1.00, 0.90, or even 0.80.

[0073] Furthermore, in the scanning optical system SOS of this embodiment, if the value of conditional expression (8) falls below the lower limit, it becomes difficult to appropriately correct various aberrations, including off-axis astigmatism.

[0074] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (8) to 0.20. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (8) to 0.25, 0.30, 0.40, 0.45, or even 0.50.

[0075] The scanning optical system SOS of this embodiment preferably satisfies the following conditional expression (9): 0.10<fO / TLO<0.80, where fO is the focal length of the scanning optical system SOS when the movable lens component arranged closest to the sample SA among the at least one movable lens component moves most toward the sample SA, and TLO is the total optical length of the scanning optical system SOS when the movable lens component arranged closest to the sample SA among the at least one movable lens component moves most toward the sample SA.

[0076] Conditional expression (9) defines the ratio between the focal length and the total optical length of the scanning optical system SOS when the movable lens component arranged closest to the sample SA among the at least one movable lens component moves closest to the sample SA. By satisfying conditional expression (9), the scanning optical system SOS of this embodiment can reduce the sensitivity to decentering coma aberration while suppressing an increase in size of the scanning optical system SOS, and can suppress the occurrence of decentering coma aberration during assembly and adjustment.

[0077] In the scanning optical system SOS of this embodiment, if the value of conditional expression (9) exceeds the upper limit, the focal length becomes long and the overall length becomes short, so that decentering sensitivity becomes high and decentering coma aberration is likely to occur during assembly and adjustment.

[0078] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit value of conditional expression (9) to 0.80. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of conditional expression (9) to 0.75, 0.70, 0.65, 0.60, or even 0.55.

[0079] Furthermore, in the scanning optical system SOS of this embodiment, if the value of conditional expression (9) falls below the lower limit, the scanning optical system SOS becomes large.

[0080] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (9) to 0.10. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (9) to 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, or even 0.50.

[0081] The scanning optical system SOS of this embodiment preferably satisfies the following conditional expression (10): 0.90 < TLO / TLI < 1.10, where TLO is the total optical length of the scanning optical system SOS when the movable lens component arranged closest to the sample SA among the at least one movable lens component moves most toward the sample SA, and TLI is the total optical length of the scanning optical system SOS when the movable lens component arranged closest to the sample SA among the at least one movable lens component moves most toward the scanning mechanism SM.

[0082] Conditional expression (10) defines the ratio of the total optical length of the scanning optical system SOS when the movable lens component arranged closest to the sample SA among the at least one movable lens component moves closest to the sample SA to when it moves closest to the scanning mechanism SM. By satisfying conditional expression (10), the scanning optical system SOS of this embodiment can suppress fluctuations in the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS that occur due to movement of the movable lens component.

[0083] In the scanning optical system SOS of this embodiment, if the value of conditional expression (10) exceeds the upper limit, the focusing position of the scanning optical system SOS is likely to shift toward the sample SA when the movable lens component arranged closest to the sample SA moves closest to the sample SA. As a result, the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is likely to be disrupted when the movable lens component arranged closest to the sample SA moves closest to the sample SA. When the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is disrupted, the focusing plane on the sample SA shifts on the optical axis, resulting in defocusing.

[0084] In the scanning optical system SOS of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (10) to 1.10. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (10) to 1.09, 1.08, 1.07, 1.06, or even 1.05.

[0085] Furthermore, in the scanning optical system SOS of this embodiment, if the value of conditional expression (10) is below the lower limit, the focusing position of the scanning optical system SOS is likely to shift toward the scanning mechanism SM when the movable lens component arranged closest to the sample SA moves closest to the sample SA. As a result, the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is likely to be disrupted when the movable lens component arranged closest to the sample SA moves closest to the sample SA. When the imaging relationship between the scanning optical system SOS and the imaging optical system TOS and the objective optical system OOS is disrupted, the focusing plane on the sample SA shifts on the optical axis, resulting in defocusing.

[0086] In the scanning optical system SOS of this embodiment, it is preferable that the lens surface closest to the sample SA is convex toward the sample SA side, and the lens surface closest to the scanning mechanism SM is convex toward the scanning mechanism SM side.

[0087] With this configuration, the scanning optical system SOS of this embodiment can reduce the Petzval sum without worsening various aberrations such as astigmatism and coma, and can improve the flatness of the image surface.

[0088] With the above configuration, chromatic aberration of magnification can be appropriately corrected over a wide wavelength band, and a scanning optical system SOS with high optical performance can be realized.

[0089] The microscope optical system of this embodiment includes the scanning optical system SOS configured as described above, a scanning mechanism SM, and an objective optical system OOS, which allows the microscope optical system of this embodiment to appropriately correct chromatic aberration of magnification over a wide wavelength range and has high optical performance.

[0090] The microscope apparatus MS of this embodiment includes a scanning optical system SOS, a scanning mechanism SM, and an objective optical system OOS, which allows the microscope apparatus MS of this embodiment to appropriately correct chromatic aberration of magnification over a wide wavelength band and has high optical performance.

[0091] Numerical Examples Hereinafter, examples of the present invention will be described with reference to the drawings.

[0092] First Embodiment FIG. 2 is a cross-sectional view of the scanning optical system SOS of the first embodiment.

[0093] The scanning optical system SOS of this embodiment has, in order from the scanning mechanism SM side, a first lens component LC1 having positive refractive power, a second lens component LC2 having negative refractive power, a third lens component LC3 having negative refractive power, and a fourth lens component LC4 having positive refractive power.

[0094] The first lens component LC1 is made up of a biconvex positive lens L11.

[0095] The second lens component LC2 is made up of a cemented negative lens consisting of a biconvex positive lens L12 and a biconcave negative lens L13.

[0096] The third lens component LC3 is made up of a cemented negative lens consisting of a biconvex positive lens L14 and a biconcave negative lens L15.

[0097] The fourth lens component LC4 is made up of a cemented positive lens consisting of a biconvex positive lens L16 and a meniscus negative lens L17 with its concave surface facing the scanning mechanism SM.

[0098] In the scanning optical system SOS of this embodiment, the third lens component LC3 corresponds to the movable lens component and the movable lens component arranged closest to the sample SA, and the positive lens L16 corresponds to the first positive lens.

[0099] Table 1 below lists the specifications of the scanning optical system SOS of this embodiment.

[0100] In the [Overall Specifications], fO denotes the focal length of the scanning optical system SOS when the movable lens component located closest to the sample SA has moved furthest toward the sample SA, and fI denotes the focal length of the scanning optical system SOS when the movable lens component located closest to the sample SA has moved furthest toward the scanning mechanism SM. TLO denotes the total optical length of the scanning optical system SOS when the movable lens component located closest to the sample SA has moved furthest toward the sample SA, and TLI denotes the total optical length of the scanning optical system SOS when the movable lens component located closest to the sample SA has moved furthest toward the scanning mechanism SM. NA denotes the numerical aperture, and Φ denotes the pupil diameter.

[0101] In the [Lens specifications], m is the order of the optical surface counted from the pupil conjugate plane CP side, r is the radius of curvature, d is the surface spacing, n(d) is the refractive index for the d-line, νd is the Abbe number for the d-line, and θgF is the partial dispersion ratio from the g-line to the F-line.

[0102] In the [variable distance data], "POS.1" is also called the first state, "POS.2" the second state, "POS.3" the third state, "POS.4" the fourth state, and "POS.5" the fifth state. "(O)" indicates the state in which the movable lens component located closest to the sample SA has moved the most toward the sample SA, and "(I)" indicates the state in which the movable lens component located closest to the sample SA has moved the most toward the scanning mechanism SM.

[0103] The units for the focal length, total optical length, pupil diameter, and radius of curvature listed in Table 1 are "mm." However, this is not limited to this, as the optical system can achieve the same optical performance even when proportionally enlarged or reduced.

[0104] The symbols in Table 1 described above are similarly used in tables of other examples to be described later.

[0105] (Table 1) [Overall specifications] fO 60.1741 fI 60.2059 TLO 118.9195 TLI 118.9190 NA 0.0500 Φ 0.3323 [Lens specifications] m r d n(d) νd θgF 1) ∞ 34.400 (Pupillary conjugate plane CP) 2) 53.8849 3.500 1.60311 60.69 3) -258.0172 13.683 4) 70.8011 5.943 1.49782 82.57 5) -21.1372 1.500 1.55298 55.07 6) 24.5355 D7 7) 29.8306 7.862 1.49782 82.57 8) -26.0676 1.500 1.67300 38.26 9) 56.0187 D10 10) 60.3317 6.922 1.60342 38.03 0.5835 11) -32.8330 1.500 1.61266 44.46 12) -37.8272 34.518 [Focal length data for each lens element] LC1 74.2230 LC2 -57.7470 LC3 -3435.3230 LC4 39.8680 [Variable interval data] D7 D10 POS.1 4.9406 2.6496 POS.2 5.5905 2.0000 (O) POS.3 4.7576 2.8335 POS.4 3.8745 3.7181 POS.5 2.0000 5.5954 (I)

[0106] Figure 3A is a diagram showing various aberrations of the scanning optical system of the first embodiment in a first state, Figure 3B is a diagram showing various aberrations of the scanning optical system of the first embodiment in a second state, Figure 3C is a diagram showing various aberrations of the scanning optical system of the first embodiment in a third state, Figure 3D is a diagram showing various aberrations of the scanning optical system of the first embodiment in a fourth state, and Figure 3E is a diagram showing various aberrations of the scanning optical system of the first embodiment in a fifth state.

[0107] In each aberration diagram, the spherical aberration diagram (LONGITUDINAL SPHERICAL ABERRATION) shows the ratio to the maximum aperture, while the astigmatic field curves, distortion, and lateral color diagrams show values ​​for the half-angle of view, and the lateral aberration diagram shows the ratio to the maximum image height. The distortion diagram shows values ​​for the d-line, while the other aberration diagrams show values ​​for the h-line, F-line, d-line, C-line, and infrared light (wavelength 1300 nm), respectively. In the astigmatism diagrams, S indicates the sagittal image plane, T indicates the meridional image plane, and the numbers 1 through 5 correspond to POS.1 through POS.5 in the variable spacing data, respectively. In the lateral color aberration diagrams, the solid line indicates values ​​for infrared light, the dashed line indicates values ​​for the C-line, the dotted line indicates values ​​for the d-line, the dashed line indicates values ​​for the F-line, and the dashed line indicates values ​​for the h-line. The same symbols as those used in the various aberration diagrams of this embodiment will be used in the various aberration diagrams of other embodiments described later.

[0108] From the various aberration diagrams, it can be seen that the scanning optical system SOS of this embodiment appropriately corrects chromatic aberration of magnification over a wide wavelength band and has high optical performance.

[0109] Second Embodiment FIG. 4 is a cross-sectional view of a scanning optical system SOS according to a second embodiment.

[0110] The scanning optical system SOS of this embodiment has, in order from the scanning mechanism SM side, a first lens component LC1 having positive refractive power, a second lens component LC2 having negative refractive power, a third lens component LC3 having negative refractive power, and a fourth lens component LC4 having positive refractive power.

[0111] The first lens component LC1 is made up of a biconvex positive lens L11.

[0112] The second lens component LC2 is made up of a cemented negative lens consisting of a biconvex positive lens L12 and a biconcave negative lens L13.

[0113] The third lens component LC3 is made up of a cemented negative lens consisting of a biconvex positive lens L14 and a biconcave negative lens L15.

[0114] The fourth lens component LC4 is made up of a cemented positive lens consisting of a biconvex positive lens L16 and a meniscus negative lens L17 with its concave surface facing the scanning mechanism SM.

[0115] In the scanning optical system SOS of this embodiment, the second lens component LC2 and the third lens component LC3 correspond to movable lens components, the third lens component LC3 corresponds to the movable lens component arranged closest to the sample SA, and the positive lens L16 corresponds to the first positive lens.

[0116] Table 2 below lists the specifications of the scanning optical system SOS of this embodiment.

[0117] (Table 2) [Overall specifications] fO 64.9202 fI 64.9287 TLO 118.9195 TLI 118.9190 NA 0.0462 Φ 0.2846 [Lens specifications] m r d n(d) νd θgF 1) ∞ 34.400 (Pupillary conjugate plane CP) 2) 42.4613 3.500 1.60311 60.69 3) 911.6064 D4 4) 56.2888 5.608 1.49782 82.57 5) -28.2537 1.500 1.55298 55.07 6) 25.3755 D7 7) 28.8850 6.766 1.49782 82.57 8) -32.2483 1.500 1.67300 38.26 9) 44.5388 D10 10) 45.8157 6.920 1.60342 38.03 0.5835 11) -31.0695 1.544 1.61266 44.46 12) -70.4012 34.517 [Focal length data for each lens element] LC1 73.7317 LC2 -71.5948 LC3 -648.0249 LC4 47.6407 [Variable interval data] D4 D7 D10 POS.1 12.2657 2.6782 7.7182 POS.2 12.1460 7.5951 2.9210 (O) POS.3 12.1782 6.2466 4.2373 POS.4 12.2109 4.8721 5.5791 POS.5 12.2792 2.0000 8.3829 (I)

[0118] Figure 5A is a diagram of various aberrations in the scanning optical system of the second embodiment in a first state, Figure 5B is a diagram of various aberrations in the scanning optical system of the second embodiment in a second state, Figure 5C is a diagram of various aberrations in the scanning optical system of the second embodiment in a third state, Figure 5D is a diagram of various aberrations in the scanning optical system of the second embodiment in a fourth state, and Figure 5E is a diagram of various aberrations in the scanning optical system of the second embodiment in a fifth state.

[0119] From the various aberration diagrams, it can be seen that the scanning optical system SOS of this embodiment appropriately corrects chromatic aberration of magnification over a wide wavelength band and has high optical performance.

[0120] Third Embodiment FIG. 6 is a cross-sectional view of a scanning optical system SOS according to a third embodiment.

[0121] The scanning optical system SOS of this embodiment has, in order from the scanning mechanism SM side, a first lens component LC1 having positive refractive power, a second lens component LC2 having negative refractive power, a third lens component LC3 having negative refractive power, and a fourth lens component LC4 having positive refractive power.

[0122] The first lens component LC1 is made up of a biconvex positive lens L11.

[0123] The second lens component LC2 is made up of a cemented negative lens consisting of a biconvex positive lens L12 and a biconcave negative lens L13.

[0124] The third lens component LC3 is made up of a cemented negative lens consisting of a biconvex positive lens L14 and a biconcave negative lens L15.

[0125] The fourth lens component LC4 is made up of a biconvex positive lens L16.

[0126] In the scanning optical system SOS of this embodiment, the second lens component LC2 and the third lens component LC3 correspond to movable lens components, the third lens component LC3 corresponds to the movable lens component arranged closest to the sample SA, and the positive lens L16 corresponds to the first positive lens.

[0127] Table 3 below lists the specifications of the scanning optical system SOS of this embodiment.

[0128] (Table 3) [Overall specifications] fO 60.1818 fI 60.3140 TLO 119.3219 TLI 119.3217 NA 0.0498 Φ 0.3313 [Lens specifications] m r d n(d) νd θgF 1) ∞ 34.400 (Pupillary conjugate plane CP) 2) 201.0644 3.500 1.60311 60.69 3) -58.2634 D4 4) 83.6809 6.037 1.49782 82.57 5) -22.7493 1.500 1.55298 55.07 6) 30.0177 D7 7) 29.4207 8) -28.8906 1.500 1.67300 38.26 9) 50.7065 D10 10) 48.8150 5.941 1.59270 35.31 0.5933 11) -55.8314 35.922 [Focal length data for each lens element] LC1 75.2829 LC2 -69.7649 LC3 -1939.4110 LC4 44.8897 [Variable spacing data] D4 D7 D10 POS.1 11.6686 7.1395 1.5000 (O) POS.2 11.6684 6.6396 2.0000 POS.3 11.6679 5.5604 3.0798 POS.4 11.6674 4.4186 4.2220 POS.5 11.6666 2.0000 6.6414 (I)

[0129] Figure 7A is a diagram showing various aberrations in the first state of the scanning optical system of the third embodiment, Figure 7B is a diagram showing various aberrations in the second state of the scanning optical system of the third embodiment, Figure 7C is a diagram showing various aberrations in the third state of the scanning optical system of the third embodiment, Figure 7D is a diagram showing various aberrations in the fourth state of the scanning optical system of the third embodiment, and Figure 7E is a diagram showing various aberrations in the fifth state of the scanning optical system of the third embodiment.

[0130] From the various aberration diagrams, it can be seen that the scanning optical system SOS of this embodiment appropriately corrects chromatic aberration of magnification over a wide wavelength band and has high optical performance.

[0131] Fourth Embodiment FIG. 8 is a cross-sectional view of a scanning optical system SOS according to a fourth embodiment.

[0132] The scanning optical system SOS of this embodiment has, in order from the scanning mechanism SM side, a first lens component LC1 having positive refractive power, a second lens component LC2 having negative refractive power, a third lens component LC3 having negative refractive power, and a fourth lens component LC4 having positive refractive power.

[0133] The first lens component LC1 is made up of a positive meniscus lens L11 with its convex surface facing the scanning mechanism SM.

[0134] The second lens component LC2 is made up of a cemented negative lens consisting of a biconvex positive lens L12 and a biconcave negative lens L13.

[0135] The third lens component LC3 is made up of a cemented negative lens consisting of a biconvex positive lens L14 and a biconcave negative lens L15.

[0136] The fourth lens component LC4 is made up of a cemented positive lens consisting of a biconvex positive lens L16 and a meniscus negative lens L17 with its concave surface facing the scanning mechanism SM.

[0137] In the scanning optical system SOS of this embodiment, the second lens component LC2 and the third lens component LC3 correspond to movable lens components, the third lens component LC3 corresponds to the movable lens component arranged closest to the sample SA, and the positive lens L16 corresponds to the first positive lens.

[0138] Table 4 below lists the specifications of the scanning optical system SOS of this embodiment.

[0139] (Table 4) [Overall specifications] fO 62.1335 fI 61.6621 TLO 118.9224 TLI 118.9239 NA 0.0487 Φ 0.3156 [Lens specifications] m r d n(d) νd θgF 1) ∞ 34.400 (Pupillary conjugate plane CP) 2) 38.6168 3.500 1.60311 60.69 3) 368.7244 D4 4) 61.3224 6.163 1.49782 82.57 5) -18.3448 1.500 1.55298 55.07 6) 21.5485 D7 7) 25.4008 7.661 1.49782 82.57 8) -30.8461 1.500 1.67300 38.26 9) 35.6888 D10 10) 50.6632 6.703 1.60342 38.03 0.5835 11) -37.0398 1.806 1.61266 44.46 12) -35.2579 34.524 [Each lens element focal length data] LC1 71.2356 LC2 -51.3767 LC3 -447.7378 LC4 35.7685 [Variable interval data] D4 D7 D10 POS.1 13.4556 1.6889 6.0226 (I) POS.2 13.4418 5.7254 2.0000 (O) POS.3 13.4484 3.2317 4.4870 POS.4 13.4478 3.3772 4.3421 POS.5 13.4535 2.0000 5.7137

[0140] Figure 9A is a diagram showing various aberrations of the scanning optical system of the fourth embodiment in a first state, Figure 9B is a diagram showing various aberrations of the scanning optical system of the fourth embodiment in a second state, Figure 9C is a diagram showing various aberrations of the scanning optical system of the fourth embodiment in a third state, Figure 9D is a diagram showing various aberrations of the scanning optical system of the fourth embodiment in a fourth state, and Figure 9E is a diagram showing various aberrations of the scanning optical system of the fourth embodiment in a fifth state.

[0141] From the various aberration diagrams, it can be seen that the scanning optical system SOS of this embodiment appropriately corrects chromatic aberration of magnification over a wide wavelength band and has high optical performance.

[0142] According to each of the above-described embodiments, chromatic aberration of magnification can be appropriately corrected over a wide band, and a scanning optical system SOS having high optical performance can be realized.

[0143] The values ​​corresponding to the conditional expressions in each example are shown below.

[0144] fO is the focal length of the scanning optical system SOS when the movable lens component among the at least one movable lens component that is positioned closest to the sample SA has moved furthest toward the sample SA, and fI is the focal length of the scanning optical system SOS when the movable lens component among the at least one movable lens component that is positioned closest to the sample SA has moved furthest toward the scanning mechanism SM.

[0145] fM1 is the focal length of the movable lens component of the at least one movable lens component that is arranged closest to the sample SA, βM1O is the lateral magnification of the movable lens component of the at least one movable lens component that is arranged closest to the sample SA when the movable lens component of the at least one movable lens component that is arranged closest to the sample SA moves closest to the sample SA, and βM1I is the lateral magnification of the movable lens component of the at least one movable lens component that is arranged closest to the sample SA when the movable lens component of the at least one movable lens component that is arranged closest to the sample SA moves closest to the scanning mechanism SM.

[0146] θgFP1 is the partial dispersion ratio of the first positive lens, νdP1 is the Abbe number of the first positive lens, and Σ(nd×d / νd) is the sum of the refractive index×center thickness / Abbe number for the lenses that make up each of the multiple lens components.

[0147] TLO is the total optical length of the scanning optical system SOS when the movable lens component among at least one movable lens component that is located closest to the sample SA has moved the most toward the sample SA, and TLI is the total optical length of the scanning optical system SOS when the movable lens component among at least one movable lens component that is located closest to the sample SA has moved the most toward the scanning mechanism SM.

[0148] [Values ​​corresponding to the conditional expressions] Example number Conditional expression 1st 2nd 3rd 4th (1) fO / fI 0.999 1.000 0.998 1.008 (2) |fM1| / fO 57.104 10.867 42.219 7.683 (3) βM1O / βM1I 0.999 0.993 0.998 1.006 (4) βM1O 1.034 1.171 0.994 -2.765 (5) βM1I 1.035 1.179 0.996 -2.750 (6) θgFP1-(0.6438-0.00172*νdP1) 0.005 0.005 0.010 0.005 (7) νdP1 38.03 38.03 35.31 38.03 (8) Σ(nd*d / νd) 0.797 0.773 0.724 0.799 (9) fO / TLO 0.506 0.546 0.504 0.522 (10) TLO / TLI 1.000 1.000 1.000 1.000

[0149] The above examples are merely illustrative of the present invention, and the present invention is not limited to these. The following content can be appropriately adopted within the scope that does not impair the optical performance of the scanning optical system SOS of this embodiment.

[0150] The scanning optical system SOS of this embodiment may have an optical member such as a filter. For example, the filter may be disposed between the scanning mechanism SM and the lens surface disposed closest to the scanning mechanism SM.

[0151] In the scanning optical system SOS of this embodiment, the lens surface may be formed as a spherical or flat surface, or as an aspherical surface. A spherical or flat lens surface is preferable because it facilitates lens processing and assembly adjustment and prevents degradation of optical performance due to errors in processing and assembly adjustment. Furthermore, a spherical or flat lens surface is preferable because it minimizes degradation of imaging performance when the image plane is shifted.

[0152] In the case where the lens surface is aspherical, the aspherical surface may be formed by grinding glass or by glass molding using a mold having an aspherical shape, or may be formed on the surface of a resin bonded to the surface of the glass. Furthermore, in the scanning optical system SOS of this embodiment, the lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

[0153] The lens surfaces of the lenses constituting the scanning optical system SOS of this embodiment may be coated with an anti-reflection coating having high transmittance over a wide wavelength range, thereby reducing flare and ghosting and achieving high-contrast optical performance.

[0154] The scanning optical system SOS of this embodiment may have an aperture stop. The aperture stop may be configured by a lens frame or the like, rather than being an independent member.

[0155] FIG. 10 is a cross-sectional view of an imaging optical system TOS that can be used together with the scanning optical system SOS of the fourth embodiment.

[0156] The imaging optical system TOS has, in order from the scanning optical system SOS side, a meniscus-shaped positive lens L21 with its concave surface facing the scanning optical system SOS side, a meniscus-shaped negative lens L22 with its concave surface facing the scanning optical system SOS side, a cemented positive lens consisting of a biconcave negative lens L23, a biconvex positive lens L24, and a meniscus-shaped positive lens L25 with its concave surface facing the scanning optical system SOS side, and a biconvex positive lens L26.

[0157] Table 5 below lists the values ​​of the specifications of the imaging optical system TOS of this embodiment.

[0158] (Table 5) [Lens specifications] m r d n(d) νd 0) ∞ 88.646 (Primary image plane IP) 1) -317.6565 5.000 1.85025 30.05 2) -103.7989 42.710 3) -40.1842 19.374 1.75575 24.71 4) -217.5611 3.300 5) ∞ 6.000 6) -105.3809 8.098 1.73800 32.26 7) 200.0000 6.000 1.66382 27.35 8) -100.0000 4.673 1.49782 82.57 9) -56.1041 0.200 10) 526.0196 6.000 1.45600 91.37 11) -86.1091 0.000

[0159] FIG. 11 is a cross-sectional view of an objective optical system OOS that can be used together with the scanning optical system SOS of the fourth embodiment.

[0160] The objective optical system OOS includes, in order from the imaging optical system TOS side, a cemented positive lens of a meniscus-shaped positive lens L31 with a convex surface facing the imaging optical system TOS side and a meniscus-shaped negative lens L32 with a convex surface facing the imaging optical system TOS side; a cemented negative lens of a meniscus-shaped negative lens L33 with a concave surface facing the imaging optical system TOS side and a meniscus-shaped positive lens L34 with a concave surface facing the imaging optical system TOS side; a biconvex positive lens L35 and a meniscus-shaped negative lens L36 with a concave surface facing the imaging optical system TOS side; a cemented positive lens of a biconvex positive lens L37, a biconcave negative lens L38, and a biconvex positive lens L39, a biconvex positive lens L40, a cemented positive lens of a meniscus negative lens L41 with its convex surface facing the imaging optical system TOS and a meniscus positive lens L42 with its convex surface facing the imaging optical system TOS, a meniscus positive lens L43 with its convex surface facing the imaging optical system TOS, and a meniscus negative lens L44 with its convex surface facing the imaging optical system TOS.

[0161] A cover glass (0.17 mm thick, refractive index 1.52439, Abbe number 54.30) is placed between the negative lens L44 and the sample SA. The space between the cover glass and the sample SA is filled with an immersion liquid (e.g., water, refractive index 1.33255, Abbe number 55.88). The immersion liquid may be, for example, glycerin (refractive index 1.4738, Abbe number 60.56).

[0162] Table 6 below lists the values ​​of the specifications of the objective optical system OOS of this example.

[0163] (Table 6) [Lens specifications] m r d n(d) νd 0) ∞ 136.000 (Imaging optical system TOS) 1) 14.1944 3.657 1.90366 31.34 2) 30.4967 3.088 1.63930 44.87 3) 9.1936 6.753 4) -10.6911 2.771 1.73211 46.18 5) -33.5526 3.621 1.56908 71.34 6) -12.4344 0.200 7) 53.5194 5.596 1.43425 94.77 8) -12.0282 0.700 1.83400 37.16 9) -51.9562 1.800 10) 32.9051 6.434 1.43385 95.25 11) -17.0068 0.700 1.73400 51.47 12) 49.8521 6.254 1.43425 94.77 13) -18.2729 0.200 14) 36.4195 4.109 1.45600 91.37 15) -53.8651 0.200 16) 27.8102 1.000 1.61266 44.46 17) 11.6829 5.369 1.62846 59.17 18) 109.9496 0.200 19) 10.9452 2.923 1.66933 49.05 20) 19.7474 0.200 21) 8.2740 6.211 2.05090 26.94 22) 1.9760 0.990 1.45850 67.84 23) ∞ 0.170 1.52439 54.30 (Cover glass) 24) ∞ 1.055 1.33255 55.88 (Immersion liquid)

[0164] In addition, the scanning optical system SOS of this embodiment may be used together with an imaging optical system TOS having specifications different from those listed in Table 5, or may be used together with an objective optical system OOS having specifications different from those listed in Table 6.

[0165] It should be understood that those skilled in the art can make various changes, substitutions, and alterations thereto without departing from the spirit and scope of the present disclosure.

[0166] MS Microscope device SM Scanning mechanism SOS Scanning optical system TOS Imaging optical system OOS Objective optical system

Claims

A scanning optical system is provided between a scanning mechanism that scans light and emits scanning light, and an objective optical system that receives the scanning light and emits it toward a sample, and also receives light from the sample and forms a primary image plane at a position conjugate to the sample, and the scanning optical system receives the scanning light and emits it toward the objective optical system, It has a plurality of lens components, It has a positive refractive power overall, At least one of the plurality of lens components is a movable lens component that is movable along an optical axis. Scanning optics.

2. The scanning optical system according to claim 1, wherein the following condition is satisfied: 0.30 < fO / fI < 1.20 however, fO: The focal length of the scanning optical system when the movable lens component, which is positioned closest to the sample among at least one of the movable lens components, moves furthest towards the sample. fI: The focal length of the scanning optical system when the movable lens component, which is positioned furthest towards the sample among at least one of the movable lens components, moves furthest towards the scanning mechanism.

3. The scanning optical system according to claim 1, wherein at least two of the plurality of lens components are movable lens components. 　 The scanning optical system according to claim 3, wherein the plurality of lens components consist of four lens components including two movable lens components and two lens components different from the movable lens components, and the four lens components have refractive powers of positive, negative, negative, and positive in order from the scanning mechanism side. 　 The scanning optical system according to claim 3 or 4, wherein the plurality of lens components consist of four lens components including two movable lens components and two lens components different from the movable lens components, and the two movable lens components are positioned second and third from the scanning mechanism, respectively.

6. The scanning optical system according to claim 1, wherein the following condition is satisfied: 5.00 < |fM1| / fO < 100.00 however, fM1: focal length of the movable lens component arranged closest to the sample among at least one of the movable lens components fO: The focal length of the scanning optical system when the movable lens component, which is positioned closest to the sample among at least one of the movable lens components, moves furthest towards the sample.

7. The scanning optical system according to claim 1, wherein the following condition is satisfied: 0.90 < βM1O / βM1I < 1.10 however, βM1O: The lateral magnification of the movable lens component located closest to the sample when the movable lens component located closest to the sample moves furthest towards the sample from at least one of the movable lens components. βM1I: The lateral magnification of the movable lens component located closest to the sample when at least one of the movable lens components is moved closest to the scanning mechanism.

8. The scanning optical system according to claim 1, wherein the following condition is satisfied: -4.00 < βM1O < 1.35 however, βM1O: The lateral magnification of the movable lens component located closest to the sample when the movable lens component located closest to the sample moves furthest towards the sample from at least one of the movable lens components.

9. The scanning optical system according to claim 1, wherein the following condition is satisfied: -5.00 < βM1I < 1.35 however, βM1I: The lateral magnification of the movable lens component located closest to the sample when at least one of the movable lens components is moved closest to the scanning mechanism.

10. The scanning optical system according to claim 1, further comprising a first positive lens having positive refractive power, which satisfies the following conditional expressions: 1<x<1 / ... 0.000 < θgFP1-(0.6438-0.00172×νdP1) < 0.050 15.00 < νdP1 < 60.00 however, θgFP1: This is the partial dispersion ratio of the first positive lens, and is expressed by the following formula using the refractive index ngP1 for the g line, nFP1 for the F line, and nCP1 for the C line of the first positive lens. θgFP1 = (ngP1-nFP1) / (nFP1-nCP1) νdP1: Abbe number of the first positive lens 11. The scanning optical system according to claim 1, wherein the following condition is satisfied: 0.20 < Σ(nd×d / νd) < 1.50 however, Σ(nd×d / νd): Sum of refractive index×center thickness / Abbe number for the lenses constituting each of the plurality of lens components 12. The scanning optical system according to claim 1, wherein the following condition is satisfied: 0.10 < fO / TLO < 0.80 however, fO: The focal length of the scanning optical system when the movable lens component, which is positioned closest to the sample among at least one of the movable lens components, moves furthest towards the sample. TLO: The total optical length of the scanning optical system when the movable lens component, which is positioned closest to the sample among at least one of the movable lens components, moves furthest towards the sample. A scanning optical system according to any one of claims 1 to 12, satisfying the following conditional expression. 0.90 < TLO / TLI < 1.10 however, TLO: The total optical length of the scanning optical system when the movable lens component, which is positioned closest to the sample among at least one of the movable lens components, moves furthest towards the sample. TLI: The total optical length of the scanning optical system when at least one of the movable lens components, the one positioned closest to the sample, moves furthest towards the scanning mechanism. The scanning optical system according to any one of claims 1-13, wherein the lens surface closest to the sample is convex toward the sample, and the lens surface closest to the scanning mechanism is convex toward the scanning mechanism. 　 A microscope optical system comprising the scanning optical system according to any one of claims 1 to 14, the scanning mechanism, and the objective optical system. 　 A microscope apparatus comprising a scanning optical system according to any one of claims 1 to 14, the scanning mechanism, and the objective optical system.

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