JPH0235408A - Microscope - Google Patents

Abstract

PURPOSE:To obtain images with proper contrast with respect to various objects by arranging an opening slit having plural openings in positions apart from an optical axis and arranging a modulator having optical control areas corresponding to the openings. CONSTITUTION:The opening slit 13 has the openings 13a and 13b in the positions apart from the optical axis O, and the modulator 17 has the optical control areas 17a and 17b corresponding to the openings 13a and 13b respectively and both areas consist of three areas which are different from each other in transmissivity. Therefore in the constitution where the openings 13a and 13b are positioned apart from the optical axis, an opening area becomes larger than the opening area in constitution where the opening areas are positioned on the optical axis O, if both types of constitution are NA. Consequently an obtained image in the former constitution is brighter even if the focus depth in the former constitution is the same as that in the latter constitution. Besides, if both openings 13a and 13b are used, an image is obserbed in twice brightness, however the focus depth becomes shallow compared with the case in which only one opening is used. In this case, the directivity of modulation contrast effect is eased, and as a result, images with proper contrast with respect to many objects are obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an S! II microscopy, such as modulation contrast microscopy and phase contrast microscopy.

[Conventional technology]

Conventional modulation contrast microscopes of this type include, for example, Japanese Patent Laid-Open Nos. 51-128548 and 57-178.
No. 212 and US Pat. No. 4,407,569.

All of these optical systems have the basic configuration shown in FIG.

That is, in FIG. 6, l is a light source, 2 is a relay lens,
3 is an aperture slit having an aperture, 4 is a condenser lens, 5 is a transparent object (specimen), 6 is an objective lens, and 7 is an optical phase gradient (refractive power) having a plurality of different density regions. A modulator 8 is an imaging plane, on which the image of the light source 1 formed by the relay lens 2 is formed at or near the front focal point of the condenser lens 4, and an aperture slit is formed at the position of the light source image. 3, and the modulator 7 is configured to be located on the exit pupil plane of the objective lens 6, that is, on the Fourier transform plane. Then, the light St is emitted and the light flux condensed by the aperture of the aperture slit 3 is irradiated onto the object 5 by the condenser lens 4, and the light flux transmitted through the object 5 is transferred to the exit pupil position, that is, the aperture image on the modulator 7 by the objective lens 6. is formed, and a modulation contrast effect is applied thereto so that the image of the transparent object 5 is formed as a visible image on the eye 8.

Specifically, the one described in JP-A-51-128548 has an opening slit 3 having a rectangular opening 3a in the center as shown in FIG. 7(A), and a rectangular opening 3a in the center as shown in FIG. As shown, the i3 error rate is high and medium, respectively.

Small (eg 100%, is%, 5%) area 7a.

7b and 7c. Also, the one described in Japanese Patent Application Laid-Open No. 178212/1983 is shown in Fig. 8 (
The opening slit 3 with the rectangular opening 3a formed on the left side as shown in FIG. 8(B) and the opening slit 3 in FIG.
) in the same area? a, 7b and 7C have a modulator 7 located on the right side.

Moreover, the one described in US Pat. No. 4,407,569 has an opening slit 3 with an arc-shaped opening 3a formed on the left side as shown in FIG. 9(A), and an opening slit 3 as shown in FIG. 9(B). The modulator 7 has regions 7a, 7b, and 7c formed into multiple annular shapes.

For example, a trapezoidal transparent object 5 as shown in FIG. 1O is observed using the microscope shown in FIG. 6, which is equipped with the aperture slit 3 and modulator 7 as shown in FIGS. To explain the case where the refractive index of the object 5 is n+
(>1), the refractive index of the medium is nt ("1), and the light ray in the direction of arrow a enters the bottom surface of the object 5 perpendicularly and then enters the inclined side surface at an incident angle of (π/2-〇,) If the angle between the ring and the incident optical axis 0 is θ, that is, it exits as a ray in the direction of the arrow, then n1sin θ, = n, 5in (θa + θb) pa.
θb = sin −' (sin θa)
−〇.

z becomes.

Therefore, when observing the left side (slope) of the trapezoidal object 5 as shown in FIG.
(i33 pass rate %), it becomes a dark image, and as shown in Figure 11 (
When observing the central part of the trapezoidal object 5 as shown in B),
Since the light ray passes through the region 7b (transmittance 15%) of the modulator 7, it becomes a gray image, and when observing the right side (slope) of the trapezoidal object 5 as shown in FIG. 11(C), the light ray passes through the modulator 7. Since the light passes through the region 7a (transmittance 100%) of No. 7, it becomes a bright image.

Incidentally, when the aperture slit 3 and the modulator 7 shown in FIGS. 8(A) and (B) are provided as in the one described in Japanese Patent Application Laid-Open No. 57-178212, the light beam exiting the object 5 and the optical axis are The relationship between the angle (θ,) formed and the intensity of the light beam is as shown in the 12th leap.

That is, if the light emitted to the object through the aperture 3a is largely refracted and all passes through the modulator region 7c, the brightness of the imaging plane will be minimum (sin), but the refractive index will be small. Then, the light from the object crosses the boundary between regions 7b and 7C and spans both regions. Since the transmittance of region 7b is greater than that of region 7c, the brightness of the image plane gradually increases as θ decreases. Is the light that passed through object 5 a region? a, 7
When spanning both b, the difference in transmittance between regions 7a and 7b and the difference in transmittance between regions 7b and 70 will change the ratio of change in θb and change in brightness within the scratch, so the brightness will change. The image increase curve has a step and (.) The brightness of the image plane is maximum (Ilax) when all the light from the object 5 passes through the region 7a.

Thus, by the modulator 7 on the Fourier transform plane,
The intensity of the Fourier-transformed light transmitted through the object 5 is modulated, and a visible image is formed on the image plane 8.

This is the basic principle of the modulation contrast microscope described in Japanese Patent Application Laid-Open No. 51-29147.

[Problem to be solved by the invention]

However, since the conventional modulation contrast microscope described above is provided with a small aperture 3a at the front focal position of the condenser lens 4, the object-side NA of the condenser lens 4 becomes small, and although the depth of focus becomes deeper, the image becomes darker. There was a drawback.

In addition, since the modulation contrast microscope described above could not change the sensitivity of the modulation contrast effect, the object 5
In some cases, the disadvantage is that images with appropriate contrast cannot be obtained. Furthermore, when the position of the aperture 3a in the modulation contrast microscope is moved away from the optical axis 0, directionality occurs in the modulation contrast effect, and since the position of the aperture 3a is fixed, it changes depending on the direction of the refraction of the object 5. Object 5
had to be rotated to observe it, which was very cumbersome to operate.

The present invention addresses the above problems, provides bright images, and provides images with appropriate contrast for various objects.
The objective is to provide a microscope that is easy to operate.

[Means and effects for solving the problems] One of the microscopes according to the present invention includes an illumination system including a light source and a condenser lens on the optical axis, and an imaging system including an objective lens disposed coaxially with the illumination system. 'itR6'ft, kn, which is located at or near the entrance pupil position of the condenser lens, or at a position within the illumination system conjugate thereto, on a different line segment orthogonal to the optical axis, aperture slits each having a plurality of apertures formed at positions apart from the objective lens, and corresponding to the apertures at or near the exit pupil position of the objective lens, or at a position in the imaging system that is conjugate thereto; A modulator having a light control region is arranged. Therefore, since the aperture is located away from the optical axis, the aperture area is larger for the same NA than when the aperture is located on the optical axis, and as a result, a brighter image can be obtained even if the depth of focus is the same. Furthermore, since the plurality of apertures are located on different line segments perpendicular to the optical axis, the directionality of the modulation contrast effect is relaxed, and as a result, images with appropriate contrast can be obtained for many types of objects.

Another microscope according to the present invention includes means for switching and shielding at least some of the plurality of apertures and the other part of the apertures. Therefore, since the direction of the modulation contrast effect can be switched, there is no need to rotate the object each time depending on the direction of the refraction effect of the object, and the operation is easy. Furthermore, by making the width of each aperture different, it is possible to change the modulation sensitivity to the phase tilt (refracting power) of an object by switching the aperture, and it is possible to change the modulation sensitivity to the phase tilt (refracting power) of the object from a small part to a large part, and from a small object to a large one. You can even observe objects.

Still another microscope according to the present invention includes an illumination system including a light source and a condenser lens on the optical axis, and an imaging system including an objective lens disposed coaxially with the illumination system. [
In the k-mirror, at the entrance pupil position of the condenser lens, or at a position in the illumination system that is conjugate thereto, there is an aperture whose width is wider in a part farther from the optical axis than in a part nearer to the optical axis. A modulator having a light control region corresponding to the aperture is disposed at or near the exit pupil position of the objective lens, or at a position in the imaging system that is conjugate thereto. Therefore, since the modulation sensitivity characteristic with respect to the phase inclination of the object becomes a gentle characteristic, it is possible to observe objects with high refractive power.

〔Example〕

Hereinafter, the present invention will be described in detail based on the illustrated embodiments.

Since the basic configuration of the optical system of this embodiment is the same as that shown in FIG. 6, its explanation will be omitted.

1(A) and (B) respectively show the aperture slit 13 and the modulator 17 of this embodiment, and the aperture slit 13 has a radial width at a position on the left side of the drawing and at a position on the top of the drawing, which is away from the optical axis O. have the same openings 13a and 13b, respectively, and the charcoal lumper 17 has light control areas 17a and 17b each corresponding to the openings 13a and 13b and consisting of three areas each having a different transmittance.

Therefore, according to this embodiment, since the apertures 13a and 13b are located away from the optical axis O, the aperture area is larger for the same NA compared to the case where the apertures are located on the optical axis 0; As a result, a bright image can be obtained even if the depth of focus is the same.

Furthermore, if both the apertures 13a and 13b are used, the relationship between the angle formed by the light beam exiting the object 5 and the optical axis O and the intensity of the light beam will be as shown in FIG. 1(C), and the depth of focus will be shallower. Images can be observed with twice the brightness. In this case, since the apertures 13a and 13b are located on different line segments perpendicular to the optical axis 0, the directionality of the modulation contrast effect is relaxed, and as a result, images with appropriate contrast can be obtained for many types of objects. can get.

Furthermore, in this embodiment, if the apertures 13a and 13b are switched and shielded, the direction of the modulation contrast effect can be switched. Therefore, there is no need to rotate the object 5 each time depending on the direction of the refraction effect of the object 5, and the operation is easy.

E11 Empress ■ The basic configuration of the optical system of this embodiment is the same as that shown in FIG. 6, so its explanation will be omitted.

2(A) and (B) respectively show the aperture slit 23 and the modulator 27 of this embodiment, and the aperture slit 23 has a radial width at a position on the left side of the drawing and at a position on the top of the drawing, which is away from the optical axis O. The modulator 27 has light control regions 27a and 27b, which correspond to the apertures 23a and 23b, respectively, and are composed of three regions having different transmittances. The openings 23a and 23b can be switched to be shielded.

Therefore, according to this embodiment, when the aperture 23a is used for illumination, the width of the corresponding light control region 27a is wide, so that the modulation sensitivity to the phase inclination of the object 5 is reduced as shown in FIG.
), it does not become very high as shown by curve a. On the other hand, when illumination is performed using the aperture 23b, the width of the corresponding light control region 27b is narrow, so the modulation sensitivity to the phase tilt of the object 5 becomes high as already shown by the curve in FIG. 2(C).

Therefore, it is possible to observe everything from parts of the object 5 with large to small phase inclinations, and from fine objects to large objects.

It goes without saying that when both apertures 23a and 23b are illuminated at the same time, a bright image can be observed as in the first embodiment.

Since the basic configuration of the optical system of this embodiment is the same as that shown in FIG. 6, its explanation will be omitted.

3(A) and (B) respectively show the aperture slit 33 and the modulator 37 of this embodiment, and the aperture slit 33 has a width at a portion farther from the optical axis O than a width at a portion closer to the optical axis O. The modulator 37 has a stepped opening 33a with a wide
has a light control region 37a corresponding to the opening 33a. As a result, the modulation sensitivity characteristic with respect to the phase inclination of the object in this embodiment becomes gentle as shown by the curve in FIG. 3(C). Therefore, objects with high refractive power can be observed.

The aperture shape is wider in the part far from the optical axis O than in the part close to the optical axis 0, and can be of various shapes, such as a triangle or a clover, as long as it matches the refractive power of the object 5. Can be designed into any shape.

4 and 5 respectively show the optical system and its main parts in the fourth embodiment, and 43 is the aperture slit I in FIG. 1(A).
The aperture slit has the same structure as 3, and polarizing plates 43a and 43b whose polarization directions are orthogonal to each other are respectively attached to the two apertures of the aperture slit. 44 is the light source 1 and the aperture slit 43.
This is a polarizing plate rotatably arranged around the optical axis O between the two.

Therefore, according to this embodiment, by rotating the polarizing plate 44, the aperture through which light (polarized light) passes, that is, the aperture that illuminates, can be changed, and as a result, the direction of modulation contrast can be changed.

Note that if it is not desired to illuminate the object 5 with polarized light, a depolarization plate may be provided on the side surface of the object 5 of the polarizing plates 43a and 43b at each opening.

It goes without saying that in each of the above embodiments, if the density modulator is replaced with a phase difference modulator, a phase contrast microscope can be obtained. Furthermore, it goes without saying that if a differential interference prism is placed near each of the aperture slit and the modulator, a differential interference mirror can be obtained.

〔Effect of the invention〕

As mentioned above, the microscope according to the present invention has the following practical advantages: it can obtain bright images even when the depth of focus is the same, it can always obtain images with appropriate contrast for objects with various phase tilts, and it is easy to operate. It has advantages.

[Brief explanation of the drawing]

Figures 1 (A), (B) and (C) are diagrams showing the open loss lift, modulator and modulation sensitivity characteristics of the first embodiment of the microscope according to the present invention, and Figures 2 (A), (B) and ( C) is a diagram showing the open loss lift, modulator and modulation sensitivity characteristics of the second embodiment, respectively, and FIGS. 3(A), CB) and (C) are diagrams showing the aperture slit, modulator and modulation sensitivity of the third embodiment, respectively. A diagram showing the characteristics,
4 and 5 are diagrams showing the optical system of the fourth embodiment and its main parts, respectively, FIG. 6 is a diagram showing the basic configuration of the optical system of the conventional example, and FIGS. 7, 8, and 9 The figures show the aperture slit and iJl device of each conventional example, Fig. 10 shows how light is refracted by a certain transparent object, Fig. 11 is an explanatory diagram of the principle of producing the modulation contrast effect, and Fig. FIG. 12 is a diagram showing the modulation sensitivity characteristics of the conventional example shown in FIG. l...Light source, 2...Relay lens, 13.23
33.43...Aperture slit, 4...Condenser lens, 5...Object, 6...Objective lens,
1727.37...Modulator, 8...Observer's eye, 44...Polarizing plate. (C) Figure 1-4 Figure 2 Figure 5 Axis ev#T111Jt Figure 1-6 Figure 11 'jpio diagram

Claims (3)

[Claims] (1) In a microscope equipped with an illumination system including a light source and a condenser lens on the optical axis, and an imaging system including an objective lens arranged coaxially with the illumination system, the entrance pupil position of the condenser lens or Arranging aperture slits each having a plurality of apertures formed on different line segments orthogonal to the optical axis and away from the optical axis at positions in the illumination system near or conjugate thereto; A microscope characterized in that a modulator having a light control region corresponding to the aperture is disposed at or near the exit pupil position of the objective lens, or at a position in the imaging system that is conjugate thereto. (2) The microscope according to claim (1), further comprising means for switching and shielding at least some of the plurality of apertures and other part of the apertures. (3) In a microscope equipped with an illumination system including a light source and a condenser lens on the optical axis, and an imaging system including an objective lens disposed coaxially with the illumination system, the entrance pupil position of the condenser lens or An aperture slit having an aperture whose width is wider at a portion far from the optical axis than at a portion close to the optical axis is disposed in the vicinity or at a position in the illumination system that is conjugate thereto, and an aperture slit having an aperture whose width is wider at a portion far from the optical axis than at a portion close to the optical axis; A microscope characterized in that a modulator having a light control region corresponding to the aperture is disposed at a pupil position, near the pupil position, or at a position in the imaging system conjugate thereto.