Microscope apparatus and microscope system

Abstract

To visualize a phase slope within a phase object.SOLUTION: A microscope device 1 comprises: an illumination optical system that illuminates a sample S; an observation optical system that guides light from the sample S; a polarizer 6; a polarization separation prism 7; and a diaphragm 2 that is located in a pupil position of a first optical system serving as one of the illumination optical system and observation optical system. A shape of the diaphragm 2 is a circle or regular polygon. A second optical system serving as other of the illumination optical system and the observation optical system is a unique polarization separation prism put on an optical path between the polarizer 6 and the polarization separation prism 7, and is configured to separate the light into two polarization advancing in a different direction where an oscillation direction is orthogonal to each other, and form an interference fringe in the pupil position of the second optical system by the separated two polarization.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The disclosure of this specification relates to a microscope apparatus and a microscope system.

Background Art

[0002] There is a known technique for obtaining contrast (hereinafter referred to as gradient contrast) by converting a local phase gradient in a phase object into an intensity distribution. Such a technique is described in Patent Document 1. In the technique described in Patent Document 1, gradient contrast can be obtained by providing a structure for intensity modulation at the pupil position of the objective lens or at a position optically conjugate to the pupil position.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the pupil position of the objective lens is usually inside the objective lens. Therefore, a microscope apparatus to which the technique described in Patent Document 1 is applicable is substantially limited to those having a pupil relay system.

[0005] Based on the above circumstances, an object according to one aspect of the present invention is to provide a new technique for visualizing a phase gradient in a phase object.

Means for Solving the Problems

[0006] A microscope apparatus according to one aspect of the present invention comprises an illumination optical system for illuminating a specimen, an observation optical system for guiding light from the specimen, a polarizer, an analyzer, and a diaphragm placed at the pupil position of a first optical system, which is one of the illumination optical system and the observation optical system, the diaphragm having a circular or regular polygonal aperture shape, wherein the second optical system, which is the other of the illumination optical system and the observation optical system, is a single polarization-separating prism placed in the optical path between the polarizer and the analyzer, which separates light into two polarizations whose vibration directions are orthogonal to each other and propagates in different directions, and the two separated polarizations at the pupil position of the second optical system One eye A polarization-separating prism that forms interference fringes is included, wherein the numerical aperture of the second optical system is greater than the numerical aperture of the first optical system which depends on the diameter of the aperture, and the interference fringes are formed at a position offset from the center of the image of the aperture projected onto the pupil position of the second optical system, and at a position overlapping with at least a portion of the image of the aperture. Another aspect of the present invention relates to a microscope apparatus comprising: an illumination optical system for illuminating a specimen; an observation optical system for guiding light from the specimen; a polarizer; an analyzer; and a diaphragm placed at the pupil position of a first optical system, which is one of the illumination optical system and the observation optical system, wherein the shape of the aperture is circular or a regular polygon. The second optical system, which is the other of the illumination optical system and the observation optical system, comprises: a single polarization-separating prism placed in the optical path between the polarizer and the analyzer, which separates light into two polarizations whose directions of vibration are orthogonal to each other and propagates in different directions, and which forms interference fringes at the pupil position of the second optical system with the two separated polarizations; and a structure for moving the polarization-separating prism in a direction orthogonal to the optical axis of the second optical system, wherein the numerical aperture of the second optical system is greater than the numerical aperture of the first optical system, which depends on the diameter of the diaphragm, and by moving the polarization-separating prism with the structure, the interference fringes are formed at a position offset from the center of the image of the diaphragm projected at the pupil position of the second optical system, and at a position overlapping with at least a part of the image of the diaphragm. A microscope apparatus according to yet another aspect of the present invention comprises: an illumination optical system for illuminating a specimen; an observation optical system for guiding light from the specimen; a polarizer; an analyzer; and a diaphragm placed at the pupil position of a first optical system, which is one of the illumination optical system and the observation optical system, wherein the diaphragm has an aperture shape of a circle or a regular polygon, and the second optical system, which is the other of the illumination optical system and the observation optical system, comprises: a polarization-separating prism placed in the optical path between the polarizer and the analyzer, which separates light into two polarizations whose vibration directions are orthogonal to each other and propagates in different directions, and which forms interference fringes at the pupil position of the second optical system with the two separated polarizations; and a structure that eccentricates the diaphragm with respect to the optical axis of the first optical system, wherein the numerical aperture of the second optical system is greater than the numerical aperture of the first optical system, which depends on the diameter of the diaphragm, and by eccentricating the diaphragm with respect to the optical axis of the first optical system with respect to the optical axis of the first optical system, the interference fringes are formed at a position offset from the center of the image of the diaphragm projected at the pupil position of the second optical system, and at a position overlapping with at least a part of the image of the diaphragm. [Effects of the Invention]

[0007] According to the above embodiment, a new technique for visualizing the phase gradient within a phase object can be provided. [Brief explanation of the drawing]

[0008] [Figure 1] This figure illustrates the configuration of a microscope apparatus 1 according to one embodiment. [Figure 2] This is a diagram illustrating the arrangement of the polarization separation prism 7. [Figure 3] This is a diagram illustrating the arrangement of interference fringes 10. [Figure 4] This is a diagram illustrating the shape of a topological object. [Figure 5] This figure illustrates the aperture image 2a projected onto the pupil position via a phase object with the shape shown in Figure 4. [Figure 6] This figure shows an example of a prism adjustment unit 12. [Figure 7] It is a diagram illustrating the configuration of the microscope apparatus 100 according to the first embodiment. [Figure 8] It is a diagram illustrating the configuration of the microscope apparatus 200 according to the second embodiment. [Figure 9] It is a diagram illustrating the relationship between the interference fringes 10 and the pupil of the objective lens. [Figure 10] It is a diagram for explaining the state of the aperture 103. [Figure 11] It is a diagram illustrating the configuration of the microscope apparatus 300 according to the third embodiment. [Figure 12] It is a diagram for explaining the size and arrangement of the aperture provided in the turret 301. [Figure 13] It is a diagram for explaining the action of the eccentric aperture 305 with respect to the optical axis. [Figure 14] It is a diagram illustrating the configuration of the microscope apparatus 400 according to the fourth embodiment. [Figure 15] It is a diagram for explaining the size and arrangement of the aperture provided in the turret 401. [Figure 16] It is a diagram for explaining the action due to the slide of the polarization beam splitter prism 122. [Figure 17] It is a diagram illustrating the configuration of the microscope apparatus 500 according to the fifth embodiment. [Figure 18] It is a diagram illustrating the configuration of the microscope system 700 according to the sixth embodiment. [Figure 19] It is a diagram illustrating the configuration of the microscope system 900 according to the seventh embodiment. [Figure 20] It is an example of an inclination contrast image acquired by the microscope system 900. [Figure 21] It is an example of a phase difference image acquired by the microscope system 900. [Figure 22] It is an example of an image generated from the inclination contrast image shown in FIG. 20 and the phase difference image shown in FIG. 21. [Figure 23] It is another example of an image generated from the inclination contrast image shown in FIG. 20 and the phase difference image shown in FIG. 21.

Embodiment for Carrying Out the Invention

[0009] FIG. 1 is a diagram illustrating the configuration of a microscope apparatus 1 according to an embodiment. FIG. 2 is a diagram for explaining the arrangement of the polarization beam splitter 7. FIG. 3 is a diagram for explaining the arrangement of the interference fringes 10. Hereinafter, the configuration and operation of the microscope apparatus 1 will be described with reference to FIGS. 1 to 3.

[0010] The microscope apparatus 1 is a microscope apparatus for observing a phase object, and is an apparatus for obtaining an inclination contrast image in which a local phase gradient in the phase object is visualized. As shown in FIG. 1, the microscope apparatus 1 includes an aperture 2, a condenser lens 3, a stage 4, an objective lens 5, a polarizer 6, a polarization beam splitter 7, and an analyzer 8.

[0011] In FIG. 1, the microscope apparatus 1 includes a transmitted illumination device, and an illumination optical system for illuminating the specimen S and an observation optical system for guiding the light from the specimen S are arranged facing each other with the stage 4 on which the specimen S is placed interposed therebetween. However, the illumination optical system including the condenser lens 3 and the observation optical system including the objective lens 5 and the polarization beam splitter 7 do not necessarily have to be arranged with the stage 4 interposed therebetween, and epi-illumination may be adopted in the microscope apparatus 1 instead of transmitted illumination.

[0012] Also, in FIG. 1, the microscope apparatus 1 is configured as an upright microscope for observing the specimen S placed on the stage 4 from above, but the microscope apparatus 1 is not limited to an upright microscope. The microscope apparatus 1 may be configured as an inverted microscope for observing the specimen S from below.

[0013] Also, although not particularly shown in FIG. 1, the microscope apparatus 1 may include an imaging device, and the inclination contrast image imaged by the imaging device may be displayed on a display device. Further, the microscope apparatus 1 may include an eyepiece lens, and a user of the microscope apparatus 1 may observe the specimen S by observing the image (virtual image) of the specimen S formed by the microscope apparatus 1 through the eyepiece lens.

[0014] Aperture 2 is an aperture diaphragm positioned at the pupil position of the illumination optical system and is located at the front focal position of the condenser lens 3. It is desirable that aperture 2 has multiple aperture blades and a variable aperture mechanism that allows adjustment of the aperture diameter. The shape of aperture 2, that is, the shape of its opening, is circular or a regular polygon. A shape closer to a circle is preferable because it results in a more natural appearance with a circularly blurred, defocused image.

[0015] The polarization separation prism 7, as shown in Figure 2, is a prism that separates incident light (linearly polarized L1) into two polarizations (linearly polarized L2 and linearly polarized L3) whose polarization directions are orthogonal to each other and propagate in different directions. It is the only polarization separation prism placed in the optical path between the polarizer 6 and the analyzer 8. The black circles and arrows in Figure 2 indicate the optical axis direction of the prism. The polarization separation prism 7 is, for example, a Nomarski prism or a Wollaston prism, but it may be other types of prisms such as a Lotion prism.

[0016] More specifically, the polarization-delimited prism 7 is positioned so that light emitted from a light source (not shown) enters it only once as it passes through the illumination optical system and the observation optical system before reaching the imaging device or eyepiece. In this respect, the microscope apparatus 1 differs from a transmission differential interference microscope having a pair of polarization-delimited prisms and a reflection differential interference microscope in which the illumination light and observation light each act once on a single polarization-delimited prism.

[0017] The polarization separation prism 7 is positioned to form interference fringes at the pupil position of the observation optical system using two polarized rays. More specifically, when backray tracing is performed from the image side towards the object side, the polarization separation prism 7 is positioned so that linearly polarized rays L2 and L3 intersect at the pupil position 9 of the observation optical system (i.e., the rear focal position of the objective lens 5), as shown in Figure 2. As a result, interference fringes are formed at the pupil position due to the interference of linearly polarized rays L2 and L3.

[0018] As shown in Figure 3, the interference fringes 10 formed by the polarization separation prism 7 have a linear shape within the pupil 11, with a width narrower than the pupil diameter of the objective lens 5, and have a gradient in the width direction of this line. These interference fringes 10 act as an intensity modulation means that modulates the intensity of incident light, similar to a neutral density (ND) filter or other light-reducing filter placed at the pupil position. Therefore, by forming the interference fringes 10 with the polarization separation prism 7, it becomes possible to achieve intensity modulation at the pupil position without directly placing a filter at the pupil position, while employing a compact configuration without a relay optical system.

[0019] If there is no phase gradient in the phase object, the principal ray passing through the phase object does not refract at the phase object and therefore passes through the center of the pupil. In contrast, if a local phase gradient is present in the phase object, the principal ray passing through the position where the phase gradient occurs is refracted by that phase gradient, and therefore passes at a position shifted from the center of the pupil by an amount corresponding to the direction and magnitude of the gradient, in a direction corresponding to the gradient. This means that by forming interference fringes 10 at a position shifted from the center of the pupil, it is possible to selectively attenuate only the light that has passed through the part of the phase object that has a phase gradient (a phase gradient with a specific direction and magnitude) corresponding to the position where the interference fringes 10 are formed.

[0020] Local phase gradients typically represent the surface shape of a phase object, more specifically, the inclination of its surface. Therefore, by adding contrast to the areas where phase gradients occur (i.e., the inclined areas), it is possible to visualize the phase object three-dimensionally. Accordingly, it is desirable that the interference fringes formed at the pupil position be formed at a position offset from the center of the aperture image projected at the pupil position in order to visualize the phase object three-dimensionally.

[0021] Figure 4 illustrates the shape of a phase object. Figure 5 illustrates the aperture image 2a projected onto the pupil position via a phase object of the shape shown in Figure 4. Referring to Figures 4 and 5, we will explain how the phase gradient of the phase object affects the contrast of its image. First, when the sample S is a flat phase object, as shown in Figure 4(a), the light from the condenser lens 3 passes through the pupil center of the objective lens 5 and forms an image that is attenuated to some extent by the interference fringes 10. Furthermore, when the sample S is a phase object with a phase gradient, for example, as shown in Figure 4(b), the light from the condenser lens 3 is refracted by the phase object. In this case, as shown in Figure 5(b), the light from the condenser lens 3 passes through a position away from the pupil center of the objective lens 5 and forms an image that is attenuated even more by the interference fringes 10 than in the case shown in Figure 5(a). Furthermore, even when the sample S is a phase object with a phase gradient in the opposite direction to that shown in Figure 4(b), the light from the condenser lens 3 is refracted by the phase object, as shown in Figure 4(c). In this case, as shown in Figure 5(c), the light rays from the condenser lens 3 pass through a position offset from the pupil center of the objective lens 5 in the opposite direction to that shown in Figure 5(b), and are not attenuated by the interference fringes 10, thus forming an image. In this way, by forming the interference fringes 10 at a position offset from the pupil center, the image becomes brighter or darker depending on the direction of the gradient of the phase object. In other words, the amount of attenuation of the light from the condenser lens 3 by the interference fringes 10 increases or decreases depending on the direction of the gradient of the phase object. As a result, the image of the phase object is visualized with relief-like contrast.

[0022] Figure 6 shows an example of a prism adjustment unit 12. In order to adjust the position in which interference fringes 10 are formed, the microscope apparatus 1 may be provided with a prism adjustment unit 12, as shown in Figure 6, for fine-tuning the position of the polarization separation prism 7. The polarization separation prism 7 is housed in the housing 13 of the prism adjustment unit 12, and the position of the polarization separation prism 7 within the housing 13 can be fine-tuned by operating handles 14 and 15.

[0023] Specifically, the prism adjustment unit 12 has a structure that slides the polarization separation prism 7 in a direction perpendicular to the optical axis of the observation optical system, and by operating the handle 14, the polarization separation prism 7 can be moved in a direction perpendicular to the optical axis of the observation optical system. Therefore, before starting observation, the user of the microscope device 1 may operate the handle 14 to adjust the position of the interference fringes 10 so that they are at the edge of the aperture image 2a as shown in Figure 3. This makes it possible to modulate the intensity according to the phase gradient of the specimen S, and to visualize the phase object in three dimensions.

[0024] Furthermore, the user of the microscope device 1 may change the direction of the phase gradient of the intensity-modulated object by operating the handle 14 to change the direction in which the interference fringes 10 are formed relative to the optical axis. In Figure 3, the interference fringes 10 are formed in the upper left direction relative to the optical axis, but by moving the polarization separation prism 7, the interference fringes 10 may be formed in the lower right direction relative to the optical axis. This makes it possible to obtain an image as if light were shone from the opposite direction to that shown in Figure 3.

[0025] Furthermore, the prism adjustment unit 12 has a structure that slides the polarization separation prism 7 in a direction parallel to the optical axis of the observation optical system, and by operating the handle 15, the polarization separation prism 7 can be moved in a direction parallel to the optical axis of the observation optical system. Therefore, before starting observation, the user of the microscope device 1 may operate the handle 15 to adjust so that interference fringes 10 are formed at the pupil position, or further, so that interference fringes 10 are formed with good contrast at the pupil position. By performing such operations, good observation becomes possible even when switching between multiple objective lenses with different pupil positions.

[0026] In the microscope apparatus 1 configured as described above, a light transmittance distribution (interference fringes) for intensity modulation can be formed at the pupil position without using a relay optical system. Therefore, with the microscope apparatus 1, it is possible to perform intensity modulation at the pupil position while employing a compact apparatus configuration, and the phase gradient within a phase object can be visualized, allowing for good observation of the phase object.

[0027] In order to achieve sufficient contrast in the image through the effect of interference fringes, it is desirable to narrow the diameter of the light beam passing through the pupil position to a size smaller than the pupil diameter. That is, it is desirable that the numerical aperture of the optical system in which interference fringes are formed at the pupil position is greater than the numerical aperture of the optical system in which aperture 2 is provided at the pupil position, as this aperture depends on the diameter of aperture 2. Therefore, in the microscope apparatus 1, it is desirable to adjust the aperture diameter of aperture 2 so that an image of aperture 2 narrowed to a size smaller than the diameter of pupil 11 (aperture image 2a) is projected at the pupil position, as shown in Figure 3.

[0028] Furthermore, the inventors of this application have found, through diligent study, that particularly good gradient contrast can be obtained when the numerical aperture of the optical system in which interference fringes are formed (the observation optical system in Figure 1) and the numerical aperture of the optical system with an aperture at the pupil position (the illumination optical system in Figure 1) satisfy the following relationship. More specifically, it is desirable that the diameter of aperture 2 be adjusted to satisfy the following relationship. Here, NA1 is the numerical aperture that depends on the diameter of the aperture of the optical system with an aperture at the pupil position, and NA2 is the numerical aperture of the optical system in which interference fringes are formed. 0.3 ≤ NA1 / NA2 ≤ 0.8

[0029] The structural difference between microscope device 1, which requires only one polarization separation prism 7, and a differential interference microscope stems from the difference in visualization principles between a differential interference microscope, which utilizes phase changes in the specimen, and microscope device 1, which utilizes refraction at the specimen surface.

[0030] A differential interference microscope (Differential Interference Microscope) visualizes the phase difference between two light rays passing through slightly different positions on a specimen (positions shifted by a so-called shear amount), making it possible to observe the surface irregularities of the specimen. Therefore, a Differential Interference Microscope requires irradiating the specimen with two separated light rays and then combining these two rays after irradiation. This necessitates either providing a pair of polarization-determinating prisms or irradiating a single polarization-determinating prism with light twice.

[0031] In contrast, microscope device 1 visualizes the specimen, which is a phase object, by utilizing the refraction caused by the unevenness (tilt) of the specimen, and does not visualize the phase difference between two light rays like a differential interference microscope. In microscope device 1, the polarization separation prism 7 forms interference fringes at the pupil position by the interference of the two light rays, thereby forming a light transmittance distribution for intensity modulation at the pupil position, and there is no need to combine the two light rays separated by the polarization separation prism 7 as in a differential interference microscope. For this reason, microscope device 1 only needs to have one polarization separation prism 7, as shown in Figure 1.

[0032] Figure 1 illustrates a configuration in which an aperture 2 is provided at the pupil position of the illumination optical system and the observation optical system is equipped with a polarization-separating prism 7. However, the aperture 2 only needs to be provided at the pupil position of one of the illumination optical system or the observation optical system, and the polarization-separating prism 7 only needs to be provided in the other of the illumination optical system or the observation optical system. Therefore, for example, the aperture 2 may be provided at the pupil position of the observation optical system and the illumination optical system may be equipped with a polarization-separating prism 7.

[0033] However, as described above, it is desirable that the interference fringes 10 formed by the polarization-separating prism 7 be provided in the optical system with the larger numerical aperture of the illumination optical system and the observation optical system. Generally, the numerical aperture of the observation optical system is higher than that of the illumination optical system, so it is usually desirable that the observation optical system be equipped with the polarization-separating prism 7. However, if the illumination optical system is equipped with the polarization-separating prism 7, the numerical aperture of the observation optical system may be adjusted by the aperture 2 so that the numerical aperture of the illumination optical system is greater than that of the observation optical system.

[0034] Figure 1 shows an example where the polarizer 6 and analyzer 8 are placed immediately next to the objective lens 5. However, the polarizer 6 and analyzer 8 can be positioned such that the polarization-separating prism 7 is located in the optical path between them. Therefore, the polarizer 6 may be placed, for example, on the light source side of the condenser lens 3. However, in this case, in order to form interference fringes with good contrast at the pupil position, any material that disrupts polarization, such as a plastic petri dish, should not be placed between the polarizer 6 and the objective lens 5. Therefore, when using a plastic petri dish, it is desirable to position the polarizer 6 on the image side of the objective lens 5, as shown in Figure 1.

[0035] The following describes specific examples of the microscope apparatus 1 mentioned above in more detail for each embodiment.

[0036] [First Embodiment] Figure 7 is a diagram illustrating the configuration of the microscope apparatus 100 according to this embodiment. The microscope apparatus 100 is a microscope apparatus that obtains a gradient contrast image. The microscope apparatus 100 will be described below with reference to Figure 7.

[0037] The microscope apparatus 100 is an upright microscope that includes an illumination optical system 110 below the stage 104 and an observation optical system 120 above the stage 104. The microscope apparatus 100 further includes a light source 101, a diaphragm 102 that functions as a field diaphragm, a diaphragm 103 that functions as an aperture diaphragm, a stage 104 on which the specimen S is placed, a polarizer 105, an analyzer 106, and an imaging device 107.

[0038] The illumination optical system 110 includes a collector lens 111 that collimates light emitted from the light source 101, a mirror 112 that reflects the light collimated by the collector lens 111 toward the specimen S, a field lens 113 that focuses the light collimated by the collector lens 111 onto the aperture 103, and a condenser lens 114 that illuminates the specimen S with light.

[0039] The aperture 103 is an aperture diaphragm positioned at the pupil position of the illumination optical system 110 and located at the front focal position of the condenser lens 114. It is desirable that the aperture 103 has multiple aperture blades and is equipped with a variable aperture mechanism that allows adjustment of the aperture diameter. The shape of the aperture of the aperture 103 is circular or a regular polygon. It is desirable for the user of the microscope apparatus 100 to adjust the aperture diameter of the aperture 103 so that the illumination optical system 110 illuminates the specimen S with light of an numerical aperture of about 30% to 80% of the numerical aperture of the observation optical system 120 (objective lens 121).

[0040] The observation optical system 120 includes an infinity-corrected objective lens 121, a polarization-separating prism 122 that separates incident light into two polarized beams whose vibration directions are orthogonal to each other and propagate in different directions, and an imaging lens 123 that focuses light from the specimen S onto the imaging device 107 to form an image of the specimen S.

[0041] The polarization separation prism 122 is positioned between the polarizer 105 and the analyzer 106. The polarization separation prism 122 is, for example, a Nomarski prism designed so that the two polarized beams separated from the incident light intersect outside the polarization separation prism 122. The polarization separation prism 122 is positioned so that the two polarized beams separated from the incident light incident from the imaging device 107 intersect at the pupil position of the observation optical system 120. Furthermore, the polarization separation prism 122 is positioned so that interference fringes are formed at the pupil position at a position offset from the optical axis.

[0042] In the microscope apparatus 100 configured as described above, the interference fringes formed by the polarization separation prism 122 at the pupil position of the observation optical system 120 act as an intensity modulation means, thereby enabling the acquisition of a gradient contrast image that visualizes the phase gradient of the specimen S. Therefore, the microscope apparatus 100 allows for the three-dimensional visualization of the specimen S in a compact configuration without a relay optical system.

[0043] [Second Embodiment] Figure 8 is a diagram illustrating the configuration of the microscope apparatus 200 according to this embodiment. Figure 9 is a diagram illustrating the relationship between the interference fringes 10 and the pupil of the objective lens. Figure 10 is a diagram illustrating the state of the aperture 103. The microscope apparatus 200 is a microscope apparatus that obtains a gradient contrast image, similar to the microscope apparatus 100. The microscope apparatus 200 will be described below with reference to Figures 8 to 10.

[0044] The microscope apparatus 200 differs from the microscope apparatus 100 in that it has an observation optical system 220 instead of the observation optical system 120. In other respects, it is the same as the microscope apparatus 100.

[0045] The observation optical system 220 differs from the observation optical system 120 in that it has multiple switchable objective lenses (objective lens 221, objective lens 222, objective lens 223). The multiple objective lenses are objective lenses with different magnifications and, for example, have different pupil diameters, as shown in Figure 9.

[0046] As shown in Figure 9, pupil 231 is the pupil of objective lens 221, which is the lowest magnification objective lens among the three objective lenses, and has the largest pupil diameter. Pupil 232 is the pupil of objective lens 222, which is the middle magnification objective lens among the three objective lenses, and has a medium pupil diameter. Pupil 233 is the pupil of objective lens 223, which is the highest magnification objective lens among the three objective lenses, and has the smallest pupil diameter.

[0047] As shown in Figure 9, the interference fringes 10 formed by the polarization separation prism 122 are formed at a position at the pupil that is offset from the optical axis (center of the pupil). The interference fringes 10 are formed at a constant position at the pupil unless the polarization separation prism 122 is moved, but in the microscope apparatus 200, the pupil diameter changes depending on the objective lens. Therefore, the positional relationship between the pupil and the interference fringes 10 changes when the objective lens is changed. Consequently, even if the position of the polarization separation prism 122 is adjusted in the microscope apparatus 200 so that the interference fringes 10 are formed at the edge of the pupil when a particular objective lens is used, the interference fringes 10 will shift away from the edge of the pupil when the objective lens is changed.

[0048] Therefore, in a microscope apparatus 200 that uses multiple objective lenses, it is desirable to adjust the aperture diameter of the aperture 103 according to the magnification of the objective lens, as shown in Figure 10. Specifically, since objective lenses with lower magnification have larger pupil diameters, it is desirable to stop down the aperture 103 as the magnification decreases. Generally, low-magnification objective lenses have small numerical apertures (NAs), so it is necessary to stop down the aperture 103 even more. In other words, by stopping down the aperture diameter of the aperture 103 when using a low-magnification objective lens, it is possible to achieve both the effect of aligning the interference fringes 10 with the edge of the pupil of the low-magnification objective lens and the effect of providing illumination that matches the NA of the low-magnification objective lens.

[0049] With the microscope apparatus 200 configured as described above, it is possible to obtain a gradient contrast image that visualizes the phase gradient of the specimen S, similar to the microscope apparatus 100, and to visualize the specimen S three-dimensionally in a compact configuration. Furthermore, with the microscope apparatus 200, the specimen S can be observed well using objective lenses with various magnifications.

[0050] [Third Embodiment] Figure 11 is a diagram illustrating the configuration of the microscope apparatus 300 according to this embodiment. Figure 12 is a diagram illustrating the size and arrangement of the aperture provided on the turret 301. Figure 13 is a diagram illustrating the operation of the aperture 305 which is eccentric with respect to the optical axis. The microscope apparatus 300 is a microscope apparatus that obtains a gradient contrast image, similar to the microscope apparatus 200. The microscope apparatus 300 will be described below with reference to Figures 11 to 13.

[0051] As shown in Figure 11, the microscope apparatus 300 differs from the microscope apparatus 200 in that, instead of an adjustable aperture diaphragm 103 located at the pupil position of the illumination optical system 110, it has multiple interchangeable apertures that are switched and used according to the objective lens housed in the turret 301. In other respects, it is the same as the microscope apparatus 200.

[0052] Instead of adjusting the aperture diameter of the diaphragm 103 according to the magnification of the objective lens, the microscope apparatus 300 inserts diaphragms of different aperture diameters into the pupil position of the illumination optical system 110 using the turret 301.

[0053] The turret 301 is provided with four apertures (apertures 302, 303, 304, and 305), as shown in Figure 12, for example. Aperture 302 is used with the medium-magnification objective lens 222. Aperture 303 is used with the high-magnification objective lens 223 and has a larger aperture than aperture 302. Aperture 304 has the largest aperture and is used when light rays are not blocked at the pupil position. Aperture 305 is used with the low-magnification objective lens 221 and has a smaller aperture than aperture 302. The shape of the apertures of apertures 303, 304, and 305 is circular or a regular polygon.

[0054] As shown in Figure 12, apertures 302 to 304 are positioned such that when inserted onto the optical axis AX of the illumination optical system 110, the optical axis AX passes through the center of the aperture. In contrast, aperture 305 is positioned such that when inserted onto the optical axis AX of the illumination optical system 110, the optical axis AX passes through a position offset from the center of aperture 305. That is, aperture 305 is eccentric with respect to the optical axis AX. The turret 301 is an example of a structure that eccentricates the center of the aperture with respect to the optical axis by switching the apertures positioned in the optical path between apertures 302 to 304 and aperture 305.

[0055] This configuration, in which the aperture 305 for low-magnification objective lenses is positioned eccentrically with respect to the optical axis AX, is particularly effective when the polarization separation prism 122 is adjusted to match a relatively high-magnification objective lens (for example, objective lens 223).

[0056] When the polarization separation prism 122 is adjusted to a relatively high-magnification objective lens (e.g., objective lens 223), the interference fringes 10 are formed relatively close to the optical axis AX to match the small pupil diameter of that objective lens. In such cases, when using a low-magnification objective lens with a large pupil diameter (e.g., objective lens 221), in order to position the interference fringes 10 at the edge of the diaphragm image, it is necessary to use a small aperture that is significantly stopped down relative to the pupil diameter. This can result in the illumination light being stopped down beyond a desirable ratio (e.g., 30% to 80%) relative to the numerical aperture of the low-magnification objective lens. Furthermore, if the illumination light is stopped down too much, the resolution may be significantly reduced or insufficient brightness may occur, making observation difficult.

[0057] However, as shown in Figure 13, by pre-offsetting the aperture 305 for the low-magnification objective lens with respect to the optical axis AX (center of the pupil 231), it becomes possible to position the interference fringes 10 at the edge of the aperture image 305a without using an aperture that is stopped down by a larger proportion than desired.

[0058] With the microscope apparatus 300 configured as described above, it is possible to obtain a gradient contrast image that visualizes the phase gradient of the specimen S, similar to the microscope apparatus 200, and to visualize the specimen S three-dimensionally in a compact configuration. Furthermore, similarly, the specimen S can be observed well using objective lenses with various magnifications. In addition, by offsetting the aperture for low magnification relative to the optical axis, it is not necessary to make the aperture diameter excessively small. Therefore, observation can be performed well over a wider magnification range than with the microscope apparatus 200.

[0059] [Fourth Embodiment] Figure 14 is a diagram illustrating the configuration of the microscope apparatus 400 according to this embodiment. Figure 15 is a diagram illustrating the size and arrangement of the aperture provided on the turret 401. Figure 16 is a diagram illustrating the operation of the polarization separation prism 122 by sliding. The microscope apparatus 400 is a microscope apparatus that obtains a tilt contrast image, similar to the microscope apparatus 300. The microscope apparatus 400 will be described below with reference to Figures 14 to 16.

[0060] As shown in Figure 14, the microscope apparatus 400 differs from the microscope apparatus 300 in that the polarization separation prism 122 is housed in the prism adjustment unit 406 and that it has a turret 401 instead of the turret 301. In other respects, it is the same as the microscope apparatus 300.

[0061] The prism adjustment unit 406 comprises a housing 407 that houses the polarization separation prism 122, and a structure that slides the polarization separation prism 122 within the housing 407 in a direction perpendicular to the optical axis of the observation optical system 220. The structure that slides the polarization separation prism 122 is operable with a handle 408, and the user of the microscope device 400 can use the handle 408 to move the polarization separation prism 122 in a direction perpendicular to the optical axis.

[0062] The turret 401 is provided with four apertures (apertures 302, 303, 304, and 405), as shown in Figure 15. The turret 401 differs from the turret 301 in that it has aperture 405 instead of aperture 305, which is eccentric with respect to the optical axis. Aperture 405 has the same aperture diameter as aperture 305, but differs from aperture 305 in that when inserted on the optical axis AX, the optical axis AX passes through the center of aperture 405. The shape of the opening of aperture 405 is circular or a regular polygon.

[0063] In the microscope apparatus 400, when using a low-magnification objective lens 221, instead of adjusting the positional relationship between the interference fringes and the aperture image using an eccentric aperture with respect to the optical axis AX, the positional relationship between the interference fringes and the aperture image is adjusted using a prism adjustment unit 406, as shown in Figure 16. More specifically, by operating the handle 408 to move the polarization separation prism 122 in a direction perpendicular to the optical axis, the interference fringes 10 are adjusted to be located at the edge of the aperture image 405a, as shown in Figure 16.

[0064] As described above, the microscope device 400, like the microscope device 300, can obtain a gradient contrast image that visualizes the phase gradient of the specimen S, and can visualize the specimen S three-dimensionally in a compact configuration. Furthermore, it is possible to observe the specimen S well using objective lenses with various magnifications, similar to the microscope device 300. Additionally, it is not necessary to excessively reduce the aperture diameter of the diaphragm for low magnification, similar to the microscope device 300. Therefore, the microscope device 400, like the microscope device 300, allows for good observation over a wide magnification range.

[0065] [Fifth Embodiment] Figure 17 is a diagram illustrating the configuration of the microscope apparatus 500 according to this embodiment. The microscope apparatus 500 is a microscope apparatus that obtains a gradient contrast image, similar to the microscope apparatus 200. The microscope apparatus 500 will be described below with reference to Figure 17.

[0066] The microscope apparatus 500 differs from the microscope apparatus 200 in that, when using the low-magnification objective lens 221, the front element of the condenser lens 114 is removed from the optical path. Other aspects are the same as those of the microscope apparatus 200.

[0067] The condenser lens 114 is a type of condenser known as a "swing-out condenser." By removing the front lens element 114a, a wider field of illumination (for example, an illumination field corresponding to observation magnifications of 10x or less) can be secured. However, when the front lens element 114a is removed, the aperture 103 does not function as an aperture diaphragm, and the pupil position of the illumination optical system 110 becomes the position of the aperture 102. Therefore, the aperture 102 is used as an aperture diaphragm to adjust the contrast.

[0068] With the microscope apparatus 600 configured as described above, it is possible to obtain a gradient contrast image that visualizes the phase gradient of the specimen S, similar to the microscope apparatus 200, and to visualize the specimen S three-dimensionally in a compact configuration. Furthermore, similarly, it is possible to observe the specimen S well using objective lenses with various magnifications. In addition, because it can secure a wider illumination field than the microscope apparatus 200, it can handle lower magnifications than the microscope apparatus 200.

[0069] [Sixth Embodiment] Figure 18 is a diagram illustrating the configuration of the microscope system 700 according to this embodiment. The microscope system 700 includes a microscope device 600 which is an inverted microscope, a control device 701 which controls the microscope device 600, a display device 702, and input devices (keyboard 703, mouse 704). The microscope system 700 will be described below with reference to Figure 18.

[0070] The microscope apparatus 600 is an inverted microscope that includes an illumination optical system 610 above the stage 604 and an observation optical system 620 below the stage 604. The microscope apparatus 600 further includes a light source 601, an electric motor 602 housing a diaphragm 603 that functions as an aperture diaphragm, a stage 604 on which the specimen S is placed, an electric motorized revolving nose (electric motor 605) fitted with multiple objective lenses (objective lenses 621, 622, and 623), a polarizer 606, an electric motor 607 which is a prism adjustment unit housing a polarization separation prism 624, an analyzer 608, and an imaging device 609. The diaphragm 603 is an aperture diaphragm positioned at the pupil position of the illumination optical system 610 and is located at the front focal position of the condenser lens 612. The shape of the opening of the diaphragm 603 is circular or a regular polygon.

[0071] The illumination optical system 610 includes a collector lens 611 that collimates the light emitted from the light source 601, and a condenser lens 612 that illuminates the specimen S with the light collimated by the collector lens 611.

[0072] The observation optical system 620 includes a plurality of objective lenses (objective lenses 621, 622, and 623) that are used interchangeably, a polarization separation prism 624 that separates incident light into two polarizations whose vibration directions are orthogonal to each other and propagating in different directions, an imaging lens 625 that focuses light from the specimen S onto the imaging device 609 to form an image of the specimen S, and a mirror 626 that reflects the light from the imaging lens 625 toward the imaging device 609.

[0073] The multiple objective lenses (objective lens 621, objective lens 622, objective lens 623) are objective lenses with different magnifications, such as 10x, 20x, and 40x. The polarization separation prism 624, positioned between the polarizer 606 and the analyzer 608, is, for example, a Nomarski prism designed so that the two polarized beams separated from the incident light intersect outside the polarization separation prism 624.

[0074] In the microscope system 700 configured as described above, the control device 701 controls the microscope device 600, automatically performing various adjustment tasks associated with changing the magnification of the objective lens. Specifically, the user of the microscope device simply selects the magnification of the objective lens to be used using the keyboard 703 or mouse 704 on the GUI displayed on the display device 702. In response to the switching instruction, the motor units 602, 605, and 607 operate and adjust to the settings corresponding to the magnification of the objective lens.

[0075] More specifically, when the magnification of the objective lens is selected, the objective lens of the selected magnification is positioned on the optical path by the motor unit 605 according to instructions from the control device 701. That is, the motor unit 605 is a first motor unit that switches between multiple objective lenses. The aperture diameter of the diaphragm 603 is electrically adjusted by the motor unit 602 according to instructions from the control device 701, so that the numerical aperture of the illumination optical system 610 is optimized for the numerical aperture of the selected objective lens. That is, the motor unit 602 is a second motor unit that adjusts the numerical aperture of the illumination optical system 610 by changing the aperture diameter of the diaphragm 603. The polarization separation prism 624 is electrically adjusted by the motor unit 607 according to instructions from the control device 701 so that its position parallel to the optical axis is adjusted, so that interference fringes are formed at the pupil position of the observation optical system 620 according to the selected objective lens. Furthermore, the polarization separation prism 624 is electrically adjusted by the motor unit 607 in a direction perpendicular to the optical axis according to instructions from the control device 701, so that interference fringes are formed at the pupil position at a position offset from the optical axis. That is, the motor unit 607 is a third motor unit that moves the polarization separation prism 624 in a direction perpendicular to the optical axis of the observation optical system 620, and is also a fourth motor unit that moves the polarization separation prism 624 in a direction parallel to the optical axis of the observation optical system 620.

[0076] The control device 701 may, for example, have a combination table of aperture diameters for the aperture 603 and positions for the polarization separation prism 624 according to the magnification of the objective lens, and may control the motorized unit described above using this combination table. Furthermore, if the motorized unit 602 has a structure that eccentricates the center of the aperture 603, it may also have a combination table that includes the center position of the aperture 603 in addition to the aperture diameter of the aperture 603 and the position for the polarization separation prism 624, and may control the motorized unit described above using this combination table.

[0077] In the second to fifth embodiments described above, users of the microscope device had to adjust the aperture diameter and the position of the polarization separation prism to obtain good gradient contrast images at various magnifications. In contrast, the microscope system 700 can automate most of these adjustment tasks. Therefore, the microscope system 700 can significantly simplify the adjustment work performed by users of the microscope device.

[0078] [Seventh Embodiment] Figure 19 is a diagram illustrating the configuration of the microscope system 900 according to this embodiment. Figure 20 is an example of a tilt contrast image acquired by the microscope system 900. Figure 21 is an example of a phase contrast image acquired by the microscope system 900. Figures 22 and 23 are examples of images generated from the tilt contrast image shown in Figure 20 and the phase contrast image shown in Figure 21, respectively. The microscope system 900 includes a microscope device 800 which is an upright microscope, a control device 701 which controls the microscope device 800, a display device 702, and input devices (keyboard 703, mouse 704). The microscope system 900 will be described below with reference to Figures 19 to 23.

[0079] Microscope device 800 is a microscope device that acquires tilt contrast images and phase contrast images, and differs from microscope device 100 in that it can switch between acquiring tilt contrast images and phase contrast images depending on the settings.

[0080] Microscope apparatus 800 is similar to microscope apparatus 100 in that it includes an illumination optical system 110. However, to accommodate phase contrast observation, it is equipped with an electric motor unit 801. The electric motor unit 801 is an electric turret housing a diaphragm 802 and a ring slit 803. The shape of the aperture of the diaphragm 802 is circular or a regular polygon. When acquiring a tilt contrast image, the electric motor unit 801 inserts the diaphragm 802 into the pupil position of the illumination optical system 110, and when acquiring a phase contrast image, it inserts the ring slit 803 into the pupil position of the illumination optical system 110.

[0081] The microscope apparatus 800 is equipped with an observation optical system 820. The observation optical system 820 differs from the observation optical system 120 in that it is equipped with an objective lens 121 and a switchable objective lens 822. The objective lens 822 is an objective lens that supports phase contrast observation, with a phase film 822a provided at the pupil position. Furthermore, in the microscope apparatus 800, the polarizer 105, analyzer 106, and polarization separation prism 122 are detachably positioned relative to the optical path.

[0082] In the microscope system 900 configured as described above, when acquiring a gradient contrast image, the control device 701 controls the microscope device 800 so that the objective lens 121 and aperture 802 are positioned on the optical path. On the other hand, when acquiring a phase contrast image, the control device 701 controls the microscope device 800 so that the objective lens 822 and ring slit 803 are positioned on the optical path, and the polarizer 105, analyzer 106, and polarization separation prism 122 are positioned outside the optical path. This makes it possible to selectively acquire a gradient contrast image (image 1001) as shown in Figure 20 and a phase contrast image (image 1002) as shown in Figure 21. In either image, phase objects that are difficult to contrast with normal bright-field observation can be visualized well. Both images 1001 and 1002 were acquired at an observation magnification of 10x.

[0083] Furthermore, the images acquired by the microscope device 800 are output to the control device 701. The control device 701 may generate new images by processing the images acquired by the microscope device 800. For example, the control device 701 may generate image 1003 shown in Figure 22 by dividing the gradient contrast image by the phase contrast image, or it may generate image 1004 shown in Figure 23 by subtracting the phase contrast image from the gradient contrast image. The control device 701 may selectively display the above four images (images 1001 to 1004) on the display device 702 according to the instructions of the user of the microscope system 900, or it may display some of these images side by side on the display device 702. It may also display some of these images superimposed on the display device 702. For example, image 1001 and image 1002 may be superimposed and displayed on the display device 702.

[0084] The embodiments described above are specific examples provided to facilitate understanding of the invention, and the present invention is not limited to these embodiments. Modified forms of the embodiments described above and alternative forms that replace the embodiments described above may be included. In other words, each embodiment can be modified in terms of its components without departing from its spirit and scope. Furthermore, new embodiments can be implemented by appropriately combining multiple components disclosed in one or more embodiments. In addition, some components may be deleted from the components shown in each embodiment, or some components may be added to the components shown in the embodiments. Moreover, the processing procedures shown in each embodiment may be performed in a different order, as long as they do not contradict each other. That is, the microscope apparatus and microscope system of the present invention can be modified in various ways without departing from the scope of the claims.

[0085] In the embodiments described above, an example was shown in which a tilt contrast image and a phase contrast image are acquired using the same microscope device. However, the tilt contrast image and the phase contrast image may be acquired using separate microscope devices, and the control device may selectively display images on the display device using the tilt contrast image and phase contrast image acquired using separate microscope devices. Furthermore, new images may be generated using these images.

[0086] In the embodiments described above, an example was shown in which the aperture has a circular opening, but the aperture opening is not limited to a circular shape. The aperture opening may also have a polygonal shape, but it is more desirable for it to be a shape that is close to axial symmetry. [Explanation of Symbols]

[0087] 1, 100, 200, 300, 400, 500, 600, 800 Microscope device 2, 102, 104, 302, 303, 304, 305, 405, 603, 802 aperture 2a, 305a Aperture image 3,114 Condenser Lens 4 stages 5, 121, 221, 222, 223, 621, 622, 623, 822 Objective lens 6, 105, 606 Polarizer 7, 122, 624 Polarization Separation Prism 8,106,608 Analyzer 9 Pupil position 10 Interference fringes 11, 231, 232, 233 Hitomi 12,406 Prism Adjustment Unit 13,407 cabinets 14, 15 Handle 101, 601 light source 104, 604 stages 107, 609 Imaging device 110, 510, 610 Illumination optical system 111, 611 Collector Lens 112,626 Miller 113,612 Field Lens 114a Front element lens 120, 220, 620, 820 observation optical systems 123, 625 imaging lens 301, 401 turrets 408 Handle L1, L2, L3 linear polarization 602, 605, 607, 801 Electric part 700, 900 Microscope Systems 701 Control Unit 702 Display device 703 Keyboard 704 Mouse 803 Ring Slit 822a phase film Images 1001, 1002, 1003, 1004 AX optical axis S specimen

Claims

1. An illumination optical system for illuminating the specimen, An observation optical system that guides light from the aforementioned specimen, Polarizer and, Analyzer and A diaphragm placed at the pupil position of the first optical system, which is one of the illumination optical system and the observation optical system, wherein the shape of the opening is circular or a regular polygon, The second optical system, which is the other of the illumination optical system and the observation optical system, includes a polarization-separating prism placed in the optical path between the polarizer and the analyzer, which separates light into two polarizations whose vibration directions are orthogonal to each other and propagating in different directions, and forms a single interference fringe in the pupil at the pupil position of the second optical system with the two separated polarizations, The numerical aperture of the second optical system is greater than the numerical aperture of the first optical system, which depends on the diameter of the aperture. The interference fringes are formed at a position offset from the center of the image of the aperture projected onto the pupil position of the second optical system, and at a position overlapping with at least a portion of the image of the aperture. A microscope apparatus characterized by the following features.

2. In the microscope apparatus according to claim 1, further, The aperture is provided with a structure that causes the center of the aperture to be eccentric with respect to the optical axis of the illumination optical system. A microscope apparatus characterized by the following features.

3. In the microscope apparatus according to claim 1 or claim 2, further, The structure includes a polarity separation prism that slides in a direction perpendicular to the optical axis of the observation optical system. A microscope apparatus characterized by the following features.

4. A microscope apparatus according to any one of claims 1 to 3, further, The structure includes a mechanism for sliding the polarization separation prism in a direction parallel to the optical axis of the observation optical system. A microscope apparatus characterized by the following features.

5. In the microscope apparatus according to any one of claims 1 to 4, The polarization-separating prism is either a Nomarski prism or a Wollaston prism. A microscope apparatus characterized by the following features.

6. An illumination optical system for illuminating the specimen, An observation optical system that guides light from the aforementioned specimen, Polarizer and, Analyzer and A diaphragm placed at the pupil position of the first optical system, which is one of the illumination optical system and the observation optical system, wherein the shape of the opening is circular or a regular polygon, The second optical system, which is the other of the illumination optical system and the observation optical system, A polarization-separating prism placed in the optical path between the polarizer and the analyzer, which separates light into two polarizations whose vibration directions are orthogonal to each other and propagates in different directions, and forms interference fringes at the pupil position of the second optical system with the two separated polarizations, A structure for moving the polarization separation prism in a direction perpendicular to the optical axis of the second optical system, including, The numerical aperture of the second optical system is greater than the numerical aperture of the first optical system, which depends on the diameter of the aperture. By moving the polarization-separating prism using the above structure, the interference fringes are formed at a position offset from the center of the image of the aperture projected onto the pupil position of the second optical system, and at a position overlapping with at least a portion of the image of the aperture. A microscope apparatus characterized by the following features.

7. An illumination optical system for illuminating the specimen, An observation optical system that guides light from the aforementioned specimen, Polarizer and, Analyzer and A diaphragm placed at the pupil position of the first optical system, which is one of the illumination optical system and the observation optical system, wherein the shape of the opening is circular or a regular polygon, The second optical system, which is the other of the illumination optical system and the observation optical system, A polarization-separating prism placed in the optical path between the polarizer and the analyzer, which separates light into two polarizations whose vibration directions are orthogonal to each other and propagates in different directions, and forms interference fringes at the pupil position of the second optical system with the two separated polarizations, The aperture is eccentric with respect to the optical axis of the first optical system, and includes, The numerical aperture of the second optical system is greater than the numerical aperture of the first optical system, which depends on the diameter of the aperture. In the above structure, by offsetting the aperture with respect to the optical axis of the first optical system, the interference fringes are formed at a position offset from the center of the image of the aperture projected onto the pupil position of the second optical system, and at a position overlapping with at least a portion of the image of the aperture. A microscope apparatus characterized by the following features.

8. In the microscope apparatus according to claim 1, claim 6, or claim 7, When the numerical aperture of the first optical system, which depends on the diameter of the aperture, is denoted as NA1, and the numerical aperture of the second optical system, NA2, then the following condition is satisfied. 0.3 ≤ NA1 / NA2 ≤ 0.8 A microscope apparatus characterized by the following features.

9. In the microscope apparatus according to claim 1, claim 6, claim 7, or claim 8, The first optical system is the illumination optical system, The second optical system is the observation optical system, The observation optical system comprises a plurality of switchable objective lenses, The aperture is an aperture with a changeable aperture diameter, or an interchangeable aperture. A microscope apparatus characterized by the following features.

10. The microscope apparatus according to claim 9, A control device is provided, The aforementioned microscope device further, A first motor unit for switching between the multiple objective lenses, A second motor unit for changing the aperture diameter of the aforementioned aperture, or for replacing the aforementioned aperture with an aperture of a different aperture diameter, The system includes a third motor that slides the polarization separation prism in a direction perpendicular to the optical axis of the observation optical system, The control device controls the first motor unit, the second motor unit, and the third motor unit in response to an instruction to switch the objective lens. A microscope system characterized by the following features.

Images