DE19718102A1 - Stereo microscope for surgical operation - Google Patents

Abstract

The stereo microscope has an objective lens (31), a variable enlargement system (33) coaxial to the objective lens and a pair of viewing systems with 2-sided symmetry relative to the enlargement system. The viewing systems employ aperture stops (34L,34R) imaging lenses (35L,35R) and eyepieces (36L,36R), offset on either side of the optical axis of the enlargement system. A further light stop (32) is arranged between the objective lens and the enlargement system. The light stop (32) covers at least at highest and lowest adjusted enlargement the inner side of the pupil of an image in the centre of the field. The image is defined via the pair of light stops (34L,34R) on the object side of the frame.

Description

The invention relates to a stereo microscope according to the Oberbe handle of claim 1.

Stereomicroscopes in which an object image is enlarged to Getting stereoscopic information is used when small parts assembled or performed various surgical operations will. Stereomicroscopes are used to make difficult work easier desired, in which the picture by a large number of people at the same time and can be observed from any direction. Around To meet requirement, there are stereomicroscopes where the light shine, the image forms observed through individual eyes through a single variable magnification system. Here are aperture diaphragms for both optical paths behind the  variable magnification system are provided around the optical axis of the variable magnification system rotatable to thereby the observation to vary direction accordingly.

In this respect, however, such an optical system has Problems than when the magnification of the optical system changes, the stereoscopic sensitivity is also changed. A Technique for solving this problem is, for example, in JP-OS Hei 4-76514. This is an optical part to compensate the stereoscopic sensitivity according to the actuation of the ver magnification moves to thereby make the stereoscopic sensitive to maintain. However, a mechanism that changes the magnification coupling with stereoscopic sensitivity, difficult to connect structure and manufacture. There is also an additional problem in that a mechanism for adjusting the stereoscopic sensitivity volume is voluminous and difficult to downsize Distance between a viewer and the object is increased where is made more difficult by the work of the viewer.

In general, a microscope is used for surgical operations used to observe the affected part of a relatively narrow area ten, and in particular requires that a deep section of the affected part and a cavity that is in an uneven surface of the object trained, can be observed favorably. For this purpose is a Optical lighting system required, with which the deep part of the affected section and the cavity are advantageously illuminated can, without creating a shadow on the affected part, and where the position of the illuminating light is not that of an ob point is shifted. To meet these two requirements, it is only necessary to make an angle between the optical axis the observation with that for illumination in the microscope to mini lubricate. Microscopes that are equipped for this purpose are in the JP-OS Sho 63-97913 and Hei 8-5923.

The use of such microscopes allows the person concerned to observe a part cheaply to a certain extent, but to to observe the affected part more cheaply, it is desirable that  in the case of microscopes, the optical axes of observation and illumination collapse on the object surface. Surgical microscopes Operations constructed accordingly are in JP-OS Hei 7-148179 and Hei 7-155336.

Now sometimes there are cases where an observation is not to be carried out with regard to an affected section, but regarding a variety of affected sections. Then it becomes necessary maneuverable that a user the position of the observation light and the Magnification for the observation of an observation system in the Mi microscope according to the affected sections to be observed poses. To do this, an optical lighting system requires settings the position of the illuminating light and an illuminating area. In addition, an efficient observation must be carried out can, such a microscope for surgical operations with respect the optical observation system can be set that the optical Lighting system follows.

At a high magnification there will be meticulous observation made, and therefore bright lighting is required, but one narrow lighting area sufficient. At a low magnification on the other hand, a relatively wide range is observed and it is therefore a wide range of lighting is required, but it does Illumination light less specific illuminance or illuminance than in the case of high magnification.

For example, in the stereo microscope according to JP-OS Hei 8-5923 the position of an illuminating light beam by means of Moving the position of the illuminating light according to one Change in the position of the object point, caused by a pre-post Back movement of a movable lens in the observation system ver pushed. This arrangement makes it easier to move the positions of the Observation and the illuminating light, but does not allow Changes in magnification for observation and lighting area to be considered.

In the microscope for surgery known from JP-OS Sho 63-97913 For operations, an objective lens is used that the  Observation and the lighting system is common, so that then when the objective lens is replicated, the positions of observation and lighting can be moved, but the lighting can not be changed.

In the microscope for surgery known from JP-OS Hei 7-155336 Operations become an optical part in the optical lighting system in association with shifting the position of the focal point tes of the optical observation system, caused by the change in Object surface (affected section), moving, which means the appropriate The latest lighting is provided for moving the object area can be.

However, in this microscope the illumination area is only set by controlling an aperture in accordance with the change in the magnification of the optical observation system. Although the size of the illumination area can be adjusted most appropriately in terms of magnification for observation, the illuminance cannot be optimized. As shown in Fig. 1, the illuminance is always constant regardless of the illumination field diameter and cannot be changed.

Therefore, this microscope is suitable for a very suitable one To provide illuminance for magnification for observation it is not, however, to adjust the illuminance to different magnifications fit.

On the other hand, in a microscope according to JP-OS Sho 53-17352 the lighting system in addition to the lens system with the variab len magnification system and the variable magnification system of the Lens system operated accordingly with that of the lighting system, which enables the lighting area and illuminance adjust.

In the optical illumination system, which is provided in such a conventional microscope shown in FIG. 2, an optical illumination system 10 including a light source 11 , an optical condenser 12 , an aperture 13 , a zoom lens unit 14 and an opening 15 , which is arranged such that the positions of the light source 11 and the opening 15 are conjugated to one another and the positions of the diaphragm 13 and the object surface 16 are conjugated to one another. Images that are close to the opening 15 and designated by the symbols, and (which are actually formed within the opening 15 ) represent sizes of images of the light source 11 that are in the opening 15 according to the increasing magnification of the zoom lens unit 14 are formed. The bole through the Sym ~ on the object surface 16 designated lighting areas show the case in which the images ~ which are formed in the opening 15, are projected onto the object surface sixteenth The size relationship between the image formed in the opening 15 and the illumination area covered on the object surface 16 is such that, for example, when the image formed in the opening 15 is viewed through the zoom lens unit 14 the image is enlarged, the illumination area on the object surface 16 is reduced to the illumination area. When the minimum image is formed in the opening 15 , the lighting area is maximum (lighting area), while when the maximum image is formed, the lighting area is minimal (lighting area).

Since the amount of light that reaches the object surface 16 from the optical illumination system 10 is constant, the illuminance becomes larger and larger as the illumination area on the object surface 16 decreases.

Fig. 3 shows the relationship between the size of the lighting area (lighting field diameter) and the illuminance in the lighting system 10 of Fig. 2. It can be seen from this graph that when the lighting area has maximum diameter (lighting area, the illuminance is the lowest) (which corresponds to the low magnification of the observation optical system), while if the illumination area is of medium size (illumination area), the illuminance becomes moderate (this corresponds to the medium magnification of the observation optical system). It can also be seen that if the illumination area is minimal With the diameter (illumination area), the illuminance becomes the highest, but the brightness of the edge of the illumination area is reduced in this case compared to that around the center, for this reason the maximum image is larger in size than the opening 15 , whereby a n Part of the light does not pass through the opening 15 . Furthermore, there is an additional reason that when a change in the magnification of the illumination optical system 10 is made only by the zoom lens unit 14 , it is imperative that the optical power decrease as the magnification increases.

In order to correct such errors, it is necessary to increase the size of the opening 15 or the number of lenses in the optical lighting system 10 . As a consequence, the microscope body is enlarged and the arrangement of the optical illumination system 10 is complicated. This causes a considerable increase in manufacturing costs and has no practical purpose.

The microscope for surgical operations known from JP-OS Hei 7-148179 and Hei 7-155336 uses a half mirror to effect the coincidence between the optical axis for illumination and observation on the object surface. This half mirror is formed with a plane parallel plate and thus there is a problem that the use of such a mirror makes the optical system responsible for producing secondary light. As shown in Fig. 4, light from the object surface is usually reflected by a first surface 20 a of a mirror 20 and introduced into an optical observation system 21 to provide an observation image. However, part of the light from the object surface is not reflected by the first surface 20 a, but passes through it. This light that has passed through is reflected on a second surface 20 b and enters the optical observation system 21 as secondary light. This causes the observation image to be doubled.

JP-OS Sho 56-120509 describes a part capable of Eliminate secondary light, and is located near a beam splitter. However, the arrangement of such a part enables the light,  reflected from this part into the observation optical system to enter. This created fear, the light that shines on the holder of the optical observation system falls into a secondary light that falls into the optical observation system occurs. In this way, the Generation of secondary light can not be completely suppressed.

The object of the invention is a stereomicroscope according to the The preamble of claim 1, in which the stereoscopic Sensitivity not noticeably changed by the change in magnification and the optical arrangement is simple and convenient.

This task is performed according to the characteristic part of the Claim 1 solved.

So with a stereomicroscope for surgical operations the illuminating light is able to adapt to a shift in the Adjust the position of the object surface, the lighting area and the illuminance related to magnification for observation are and a beam splitter is provided, Lm the optical axes for Observation and lighting coincide on the object surface to ensure good observations free from ambient light and light reflections enable, is the surgical microscope with an optical ob system in which a special lens system is moved, by a shift in the position of the focal point on the side of the Object area and a change in magnification for observation too enable. The microscope also has an optical lighting system for applying illuminating light to the object surface without passing through the optical observation system to run, the optical loading lighting system is provided with lens systems that are able itself depending on the shift in the position of the focal point and changing the magnification for observation in the optical Moving observation system.

The microscope in particular has an optical observation system and an optical lighting system for illuminating the object area without the illuminating light through the optical observation system runs so that the optical axes of observation and lighting combined by a beam splitter and onto the object surface  leads, the beam splitter is designed in a wedge shape.

Also, a light absorption plate with a curved upper be placed close to the beam splitter in a position where Light arrives from the lighting system through the beam splitter is reflected.

A smooth transparent plate can be parallel to the bottom of the Microscope body between the beam splitter and the object surface be classified.

Further refinements of the invention are as follows Description and the dependent claims.

The invention is described below with reference to the accompanying figures Illustrated embodiments illustrated in more detail.

Fig. 1 shows a diagram regarding the relationship between the illumination region (light field diameter) and the illuminance in a conventional microscope for surgical operation,

Fig. 2 is a conceptual view for explaining the principle of the illumination optical system in a conventional microscope,

Fig. 3 is a diagram regarding the relationship between the illumination region (light field diameter) and the illuminance achieved with an illumination system according to Fig. 2,

Fig. 4 is a view for explaining the function of a half mirror, to coincide the optical axes of the observation and illumination on the object surface in the conventional microscope,

Fig. 5 shows a fundamental arrangement of an observation optical system of a stereomicroscope according to the invention,

Fig. 6 is approximately system for reducing the overall length of the optical system of a perspective view of a specific arrangement comprising an objective lens and a variable Vergröße. 5,

Fig. 7 shows an example of the optical system of a stereo microscope for several observers,

Fig. 8 (a), (b) and (c) are sectional views of configurations in which the magnification of the optical system is changed in accordance with a first embodiment of the stereomicroscope,

Fig. 9 (a), (b) and (c) are diagrams illustrating the spherical aberration in the first embodiment,

Fig. 10 (a), (b) and (c) are diagrams showing the astigmatism in the first embodiment,

Fig. 11 (a), (b) and (c) diagrams the distortion characteristics are represented in the first embodiment,

Fig. 12 (a), (b) and (c) are cross sections, in which the magnification of the optical system is changed in accordance with a second embodiment showing an arrangement,

Fig. 13 (a), (b) and (c) are diagrams illustrating the spherical aberration in the second embodiment,

Fig. 14 (a), (b) and (c) are diagrams showing the astigmatism in the second embodiment,

Fig. 15 (a), (b) and (c) are diagrams that represent the distortion in the second embodiment,

Fig. 16 (a) to 16 (i) are sectional views, in which the magnification of the optical system is changed in accordance with a third embodiment, the voltages Anord show,

Fig. 17 (a) -17 (i) are diagrams illustrating the spherical aberration in the third embodiment,

Fig. 18 (a) to 18 (i) are diagrams showing the astigmatism in the third embodiment,

Fig. 19 (a) to 19 (i) are diagrams properties inherent distortion are represented in the third embodiment,

Fig. 20 (a) to 20 (i) are sectional views, in which the magnification of the optical system is changed in accordance with a fourth embodiment of the voltages Anord show,

Fig. 21 is a schematic side view showing an optical arrangement of the microscope for surgical operation,

Fig. 22 is a conceptual view for explaining the arrangement of the optical illumination system of the microscope for surgical operations.

Fig. 23 is a diagram regarding the relationship between the illumination region (light field diameter) and the illuminance in the illumination optical system of Fig. 22,

Fig. 24 is a sectional view with respect to an arrangement, developed along the optical axis, an optical illumination system according to a fifth embodiment,

Fig. 25 (a) and (b) are views showing the arrangements according to which illumination light is guided by the illumination optical system of Fig. 24 on an object surface,

Fig. 26 is a sectional view of an assembly along developed the optical axis of an illumination optical system accordingly a modification of the fifth embodiment,

Fig. 27 (a) and (b) are views showing the arrangements in which illumination light is guided by the illumination optical system of Fig. 26 on an object surface,

Fig. 28 is a view for explaining the function of a beam splitter,

Fig. 29 is a view for explaining the function of a light absorption plate,

Fig. 30 (a), (b) and (c) are views for specifically Erläu tern of angles of incidence on the light absorbing plate,

Fig. 31 is a view for explaining the function of a transparent plate.

Stereoscopic sensitivity in the stereomicroscope depends from an angle with right and left optical axes with the object area, determined by the positions on the left and right side entry pupils (hereinafter referred to as the internal angle designated). The internal angle can be expressed as the angle defined by lines that extend from the centers of the entry pu extend pills to the center of the object. If the entrance pupil len are circular, the internal angle can be represented by an angle be tated that spans a distance between their centers. When the pupils are covered, it is the intersection of a segment between the entrance pupils with the pupil the center of the pu  pill. In the following description, a direction in which the optical axes in a plane perpendicular to the optical axes bound, referred to as the lateral direction, while one direction perpendicular to the lateral direction referred to as the vertical direction becomes. If the entrance pupils from the outside in a lateral direction are covered, the stereoscopic sensitivity is reduced where however, if they are covered from the inside, the stereoscopic sensitivity is increased. If a the passage of light blocking area at an intermediate point as the center between the optical axes is enlarged and the pupils covered from the outside there will be an increase in stereoscopic sensitivity presses, whereas if the Be is richly reduced and the pupils are covered from the inside, a reduction in stereoscopic sensitivity is suppressed.

According to FIG. 1, an objective lens 31 , a light diaphragm 32 , a variable magnification system 33 with at least one image point I within it and coaxial to the objective lens 31 , left and right-hand aperture diaphragms 34 L and 34 R for observation, the exit side to the magnification system 33 are arranged, left and right side optical imaging systems 35 L and 35 R coaxial to the aperture stops 34 L and 34 R for forming the images and adjusting their orientations in such a way that stereoscopic viewing can be carried out with the eyes, and left and right side eyepieces 36 L and 36 R for enlarging the images formed by the imaging systems 35 L and 35 R. The aperture diaphragms 34 L and 34 R can be arranged within the imaging systems 35 L and 35 R or replaced by the frames of lenses that form the imaging systems 34 L and 34 R. In order to also prevent the change in stereoscopic sensitivity by the eyes, each optical imaging system comprises a reflection device which comprises a prism or a mirror which can be inserted into any light beam.

When the optical system of the microscope is constructed as listed above, the stereoscopic sensitivity increases in proportion to the magnification of the variable magnification system 33 . The images of the aperture diaphragms 34 L and 34 R of the magnification system 33 are formed where the stereoscopic sensitivity is greatest, on the object side of the magnification system 33 , and the light diaphragm 32 is arranged coaxially with the magnification system 33 in the vicinity of the images. The aperture 32 , which is seen for adjusting the stereoscopic sensitivity, corresponds to an aperture 32 a from FIG. 6, which covers the edge of the entrance pupil in the position in which the magnification system 33 has its maximum magnification, or an aperture 32 b, which covers the inside of the entrance pupil in the position in which the magnification system 33 has its minimum magnification. After the aperture 32 a begins to cover the entrance pupil, the increase in stereoscopic sensitivity is suppressed, while when the aperture 32 b begins to cover the entrance pupil, the reduction in stereoscopic sensitivity is suppressed. In particular, if at least 30% of the area of the entrance pupil is covered, a considerable effect is brought about. If the magnification system 33 has a focal length adjustment function, the objective lens 31 need not be used, while the diaphragm 32 is then only to be arranged in front of the magnification system 33 . An objective lens capable of changing a working distance (WD) can be considered a variable magnification system.

The optical system shown in FIG. 5 has a large overall length, which is why, according to FIG. 6, four or more reflecting surfaces are used in order to reduce the distance between the object surface and the eyes of the observer so as to make it easier to work with the microscope . It is also common to provide reflection surfaces for photographic and video systems, auto focus detection systems and a path divider for a large number of observers. In this case, it is desirable that an afocal light beam be used in an optical beam splitter system. In this way, the variable magnification system in a variable magnification system 31 a and optical image transmission systems 33 b and a system comprising the lens lens 31 , the optical variable magnification system 33 a, the image transmission systems 33 b and the optical imaging systems 35 L and 35 R are designed to form an afocal system.

The imaging system has a divider prism 47 on the image side of the variable magnification system 33 a in order to even out the observation area of the imaging area. Since a displacement between the pupil's rule for a large number of observers is preferably to be kept to a minimum, it is desirable that the optical path between the image transmission system 33 b and the imaging systems 35 L and 35 R is split. If active autofocusing is carried out with the radiation of infrared light, it is desirable that infrared light which deviates in wavelength from visible light and changes the focal length of a lens does not pass through a lens system. Then it is desirable that the optical system is split in front of the objective lens 31 or between the objective lens 31 and the Ver magnification system 33 a. If the optical path between the objective lens 31 and the magnification system 33 a is split, it is desirable to provide a light splitting element 46 for transmitting visible light and reflecting infrared light, since it is difficult to produce a splitting element with properties that allow infrared light to pass through and are suitable for reflecting visible light.

Furthermore, the arrangement is designed in such a way that a large number of people who can change the directions of observation as desired with the same stereoscopic sensitivity and can therefore perform complicated work in comfortable positions. Fig. 7 shows an embodiment of a stereo microscope, in which a large number of people can make observations. Here, a prism system is constructed such that a main observer is arranged on the passage side of a Tei lerprismas 37 , while a subordinate observer is ter on the reflection side thereof. The optical system for the main observer comprises a prism 38 , aperture diaphragms 39 L and 39 R and an imaging system 40 L and 40 R. To make the position of the main observer comfortable, the imaging systems 40 L and 40 R can be rotated about an axis, which contains the intermediate point of both optical axes. In this case, a rotation angle of about 60 ° is sufficient since the main observer actuates the microscope body.

On the other hand, the optical system for the subordinate observer comprises the reflection side of the splitting prism 37 , prisms 40 and 41 , rotating prisms 42 , aperture diaphragms 43 L and 43 R and imaging systems 44 L and 44 R, while eyepieces are not shown. The entire optical system from the splitting prism 37 to the child observer about the axis of the optical system for the main observer, which are rotated passes through the prism 37th In this case, the embodiment is such that when the optical system for the main observer is rotated, the optical system for the subordinate observer is not moved. Furthermore, the arrangement is such that the entire optical system can be rotated following the prisms 41 , the optical axis on the exit side of the prism 41 forming the axis of rotation. In addition, an optical system can be rotated downstream of the aperture diaphragms 43 L and 43 R with the optical axis on the exit side of the prisms 42 as an axis of rotation. The optical system for the sub-observer can be rotated with respect to axes of rotation, the sub-observer is not forced to take an uncomfortable position even if the main observer inclines the microscope body in any direction.

Wherever a multitude of observers are allowed to observe not all optical path lengths from the variable magnification system is identical to the aperture diaphragm will. When the pupil position is shifted, this ver appears shift as a difference in brightness in the lateral direction the image area. Except when the picture is through the aperture to adjust the stereoscopic sensitivity is covered, it can be used. However, to reduce observer fatigue, and good To ensure stereoscopic sensitivity, it is necessary that the ratio between the darkest part and the lightest part in lateral direction of the image is within 1: 3. Therefore the aperture diaphragms arranged for the observers so that the difference the brightness of the image surface, covered by the aperture to on position of the stereoscopic sensitivity, is within 1/3.  

It is desirable that the main viewer and the subordinate viewer change the observation areas according to their roles while viewing the same object. This is accomplished by employing a lens system to change the magnification in the imaging system to turn the magnification off. Since the optical system for the main observer in the positions of the aperture diaphragms is different from that of the subordinate observer, an afocal light beam is required to use an imaging system that is common to both in order to keep the position of the observation image constant. This is achieved by an arrangement such that afocal variable magnifying lenses 45 L and 45 R are arranged in front of the imaging system. This makes it possible to change the magnification with a constant focus position regardless of the presence of the afocal variable magnifying lenses. Since many prisms are used in the optical system of the microscope, the image is decentered due to their manufacturing defects, but this eccentricity can be corrected by moving part of the afocal variable magnifying lenses 45 L and 45 R in a direction perpendicular to the optical axes.

First embodiment

Fig. 8 (a), (b) and (c) show arrangements in which the Ver magnification of the optical system of this embodiment to 0.42 × 0.84 × 1.68 × or is changed. Figure 9 (a). (B) and (c) show the spherical aberration when the magnification of × 0.42, × is changed 0.84 or 1.68 ×. Fig. 10 (a), (b) and (c) show the Astigmatismuseigenschaften and Fig. 11 (a), magnifications (b) and (c) the distortion characteristics at these Ver.

Below are the numerical data of the optical system reproduced the first embodiment.

Object area

In the above data, the objective lens extends from r 1 to r₂, the variable magnification system from r₉ to r₁₉ and the picture transmission system from r₂₄ to r₄₀. Table 1 shows the values of D1-D3, are the distances between lens units that are moved when the Magnification is changed.

Table 1

A = 42, a = 10, 100 <L <200, f = 168, D = 10.5, FN = 19.

When the internal angle is in the range of 1 ° to 10 ° the stereoscopic sensitivity is generally good. In absence the aperture for setting the stereoscopic sensitivity is the internal angle 12 ° at the highest magnification, and a microscope can with which it is easy to observe.

Second embodiment

Fig. 12 (a), (b) and (c) show arrangements in which the Ver magnification of the optical system of this embodiment to 0.42 × 0.84 × 1.68 × or is changed. Fig. 13 (a), (b) and (c) show the spherical aberration when the magnification of × 0.42, × 0.84 or 1.68 × is changed. Fig. 14 (a), (b) and (c) show the Astigmatismuseigenschaften these changes magnification, while FIG. 15 (a), (b) and (c) show the distortion characteristics at these magnification changes.

Below are the numerical data of the optical system reproduced the second embodiment.

Object surface

In the above data, the objective lens ranges from r₁ to r₂, the variable magnification system from r₁₁ to r₂₁ and the image transfer system from r₂₆ to r₄₀. Table 2 shows the values of D1-D3 that represent the distances between lens units that are moved, when the magnification is changed.

Table 2

A = 42, a = 10, 100 <L <200, f = 168, D = 10.5, FN = 19.

In the second embodiment, there is a distance between the Objective lens and the variable magnification system of the first version tion form provided so that a light splitting prism in between can be set, and the curvature of the field is corrected.

Third embodiment

Fig. 16 (a) to 16 (i) show arrangements in the optical system of this embodiment at a working distance (WD) of 200 and a magnification of 0.45 × (Fig. 16 (a)), a WD of 200 and a Magnification of 0.9 × ( Fig. 16 (b)), a WD of 200 and a magnification of 1.8 × ( Fig. 16 (c)), a WD of 300 and a magnification of 0.3 × ( Fig. 16 (d)), a WD of 300 and a magnification of 0.6 x (Fig. 16 (e)), a WD of 300 and a magnification of 1.2 x (Fig. 16 (f)), a WD of 400 and a magnification of 0.23 × ( FIG. 16 (g)), a WD of 400 and a magnification of 0.45 × ( FIG. 16 (h)) and a WD of 400 and a magnification of 0.9 × ( Fig. 16 (i)).

Fig. 17 (a) -17 (i) show the spherical aberration at a WD of 200 and magnifications of × 0.45, × 0.9 and 1.8 × (Fig. 17 (a) to 17 (c)) , a WD of 300 and magnifications of 0.3 ×, 0.6 × and 1.2 × ( FIGS. 17 (d) to 17 (f)), and a WD of 400 and magnifications of 0.23 ×, 0 , 45 × and 0.9 × ( Fig. 17 (g) to 17 (i)).

Fig. 18 (a) to 18 (i) show Astigmatismuseigenschaften at a WD of 200 and magnifications of × 0.45, × 0.9 and 1.8 × (Fig. 18 (a) to 18 (c)), a WD of 300 and magnifications of 0.3 ×, 0.6 × and 1.2 × ( Fig. 18 (d) to 18 (f)) and a WD of 400 and magnifications of 0.23 ×, 0.45 × and 0.9 × ( Figs. 18 (g) to 18 (i)).

Fig. 19 (a) to 19 (i) show distortion characteristics at a WD of 200 and magnifications of × 0.45, × 0.9 and 1.8 × (Fig. 19 (a) to 19 (c)), a WD of 300 and magnifications of 0.3 ×, 0.6 × and 1.2 × ( Fig. 19 (d) to 19 (f)) and a WD of 400 and magnifications of 0.23 ×, 0.45 × and 0.9 × ( Figs. 19 (g) to 19 (i)).

Below are the numerical data of the optical system of the third embodiment.

Object area

In the above data, the objective lens ranges from r₁ to r₈, the variable magnification system from r₁₆ to r₂₆ and the image transfer system from r₃₁ to r₄₅. Table 3 shows the values of D1-D6 that Are distances between lens units that are moved when the Magnification is changed.

Table 3

A = 42, a = 10, 100 <L <200, f = 210, D = 10.5, FN = 22.

The following lens system is also used as an imaging lens turns.

In the third embodiment, even if WD of 200 is changed to 400, the stereoscopic sensitivity favorable hold and ensure a good picture.

The numerical data at 1 × and 1.5 × magnifications of the afocal variable magnification system 45 L and 45 R are as follows:

Fourth embodiment

Fig. 20 (a) to 20 (i) show arrangements in the optical system of this embodiment at a WD of 230 and a magnification of 0.36 × (Fig. 20 (a)), a WD of 230 and a magnification of 0, 71 × ( FIG. 20 (b)), a WD of 230 and a magnification of 1.43 × ( FIG. 20 (c)), a WD of 300 and a magnification of 0.3 × ( FIG. 20 (i.e. )), a WD of 300 and a magnification of 0.6 × ( FIG. 20 (e)), a WD of 300 and a magnification of 1.19 × ( FIG. 20 (f)), a WD of 380 and a magnification of 0.23 × ( FIG. 20 (g)), a WD of 380 and a magnification of 0.47 × ( FIG. 20 (h)) and a WD of 380 and a magnification of 0.94 × ( Fig. 20 (i)).

Below are the numerical data of the optical system of the fourth embodiment.

Object area

In the above data, the objective lens ranges from r₁ to r₁₁, the variable magnification system from r₁₈ to r₃₂ and the image transfer system from r₃₈ to r₅₀. Table 4 shows the values of D1-D6 that Are distances between lens units that are moved when the Magnification is changed.

Table 4

A = 42, a = 10, 100 <L <200, D = 10.5, FN = 22.

The following lens system is also used as an imaging lens turns.

Fifth embodiment

Before this embodiment is described, the microscope for surgical operations shown in Fig. 21 is described, which includes a microscope body 51 , a lens mount system 52 and an eyepiece system 53 . The microscope body 51 is provided with an optical observation system 60 comprising a variable magnification system 54 for changing the magnification for observing the object and an optical objective system 55 for shifting the position of the focal point, and with an optical illumination system 56 . In the microscope body 51 , in the position in which the optical axis of the observation system 60 crosses that of the illumination system 56 , a beam splitter 57 is arranged in order to let these optical axes coincide on the object surface. Furthermore, a light absorption plate 58 for preventing the generation of secondary light and reflections is arranged near the beam splitter 57 . A transparent plate 59 is arranged on the bottom of the microscope body 51 parallel to it.

According to FIGS. 22 and 23, the optical BL LEVEL includes processing system 56 includes a light source 61, a condensing unit 62, a variable aperture 63, a zoom lens unit 64, a focusing lens 65 and an aperture 66 so that illumination light from the illumination system 56 onto the examined object surface 67 falls. This arrangement is designed such that the position of the light source 61 is conjugated to that of the opening 66 and the position of the variable diaphragm 63 is conjugated to that of the object surface 67 by the optical components. The focusing lens 65 is provided for the purpose of moving along the optical axis in connection with the lens system 55 , which is arranged in the observation system 60 to determine the position of the focal point and to adjust the position of the illuminating light to the position of the focal point. The variable aperture 63 and the zoom lens unit 64 are set to an illumination area and its illuminance that is most suitable for the magnification for observation (observation area) of the observation system 60 in connection with the variable magnification system 54 , which determine the observation area.

In Fig. 22, images which are close to the aperture 66 and are designated by symbols, and (which are actually formed within the aperture 66 ) represent sizes of images of the light source 61 which are in the aperture 66 in accordance with increasing magnification of the zoom lens unit 64 are formed. The lighting areas indicated by the symbols ∼ on the object surface 67 show the case in which the images ∼ formed in the opening 66 are projected onto the object surface 67 . Also in Fig. 23 the symbols ~ BL LEVEL the corresponding processing areas.

When the object surface 67 is viewed at a low magnification in the microscope, the magnification for the observation of the observation system 60 is set to a minimum. Observation at low magnification requires a large area of illumination. Therefore, the magnification of the zoom lens unit 64 is set to a minimum in the illumination system 56 . In this case, the minimum image 1 is formed in the opening 66 and the maximum illumination area on the object surface 67 is illuminated. In this microscope, the amount of light that is thrown onto the object surface 67 by the illumination system 56 is constant. When the lighting area changes with the magnification caused only by the zoom lens unit 64 , the illuminance increases as the lighting area becomes small. In this way the illuminance of the illuminated area is minimized.

If the object surface 67 is viewed with medium magnification, the magnification of the viewing system 60 is set to an average value. Since the observation area on the object surface 67 in this case is small compared to that at a low magnification, an illumination area of medium size is sufficient. Therefore, the magnification of the zoom lens unit 64 is enlarged and the image of the same size as the diameter of the opening 66 is formed, thereby bringing the illumination area to an average. The illuminance of the lighting area is larger than that of the lighting area.

When viewed at the highest magnification, the magnification of the observation system 60 is set to a maximum. Therefore, in this case, the observation area is smaller than in the case of medium magnification and a minute observation is made with respect to a considerably smaller part compared to the case of low magnification, a smaller illumination area being necessary to improve the illuminance. However, if the lighting area is reduced only by the zoom lens unit 64 , as mentioned above, the illuminance is improved, but the peripheral edge of the lighting area becomes darker than the center thereof. This can affect the observation. This disadvantage could be caused by oversizing the microscope body, complicating the optical system and thus increasing the manufacturing costs.

Although the illuminance of the lighting area in the observ Attention is not particularly improved with high magnification meticulous observation sufficient with some degree of illuminance be carried out, the for the observation at medium Ver necessary illuminance is satisfactory.

Therefore, in this microscope, the magnification of the zoom lens unit 64 of the illumination system 56 is set as in the case of observation at medium magnification, so that the image has the same size as the diameter of the opening 66 , for which purpose the variable diaphragm 63 is closed accordingly, to get the minimum lighting area. Here, although the available illuminance is the same as in the case of the lighting area, light that does not pass through the opening 66 and causes reflections and sub-light can be prevented from occurring, thereby preventing deterioration in the optical behavior. As a result, it becomes possible that the peripheral area of the lighting area has the same brightness as the central area thereof.

Fig. 24 shows the arrangement of the illumination system 56 according to the fifth embodiment, constructed on the basis of the principles set forth above. The illumination system 56 comprises a light guide fiber 71 for transmitting light from an unillustrated light source, a condenser system 72, a variable diaphragm 73, a prism 74, a infrarotlichtausfilterndes filter 75, an optical filter 76, a zooming lens unit 77, a focusing lens 78, a rendering lens 79 and a prism (aperture) 80 for directing illuminating light onto the object surface.

The zoom lens unit 77 , which comprises two convex and one concave lens, which is designed to be movable along the optical axis. The focusing lens 78 is composed of a convex lens and can be moved along the optical axis as in the zoom lens unit 70 . The variable aperture 73 and the zoom lens unit 77 are provided to adjust the lighting area and the illuminance, which allows a favorable illumination of the viewing area in connection with the change in magnification by the variable magnification system 54 to change the magnification for viewing the viewing system 60 . The focusing lens 78 is used to supply the most suitable illuminating light for the object surface in connection with the lens system 55 for adjusting the position of the focal point of the viewing system 60 to the object surface. This arrangement is such that the position of the exit end of the optical fiber 72 is conjugated to the image display position of the fiber end of the prism 80 by the optical components, while the position of the variable aperture 73 is conjugate to the object surface (not shown).

Fig. 25 (a) and (b) show corresponding positions of the zoom lens unit 77 at observations with low magnification and with medium and high magnification, wherein the illumination light is passed through the illumination system 56 of FIG. 24 on the object surface. The wedge-shaped beam splitter 57 is arranged below the lighting system 56 so that illuminating light from the illuminating system 56 falls on the object surface (not shown), while viewing light falls from the object surface into the viewing system (not shown). The arrangement of the beam splitter 57 enables the optical axis for illumination to coincide with the optical axis for viewing on the object surface.

The transparent plate 59 is arranged parallel to the bottom of the microscope body and is provided to prevent dust from entering the microscope body. In addition, in the vicinity of the beam splitter 57, the light absorption plate 58 is arranged, the secondary light, to which light from the lighting system 56 , which is reflected by the beam splitter 57 , is prevented from penetrating into the observation system.

Referring to FIG. 26, the lighting system 56 includes the light guide fiber 71 for transmitting light from an unillustrated light source, the Kondensarsystem 72, the variable orifice 73, the zoom lens unit 77, a fixed lens 77 ', the focusing lens 78, the reimaging lens 79 and the prism (aperture) 80 for directing illuminating light onto the object surface.

Fig. 27 (a) and (b) show corresponding positions of the zoom lens unit 77 at observation at low magnification and the weils medium and high magnification, wherein illumination light is guided by the illumination system 56 of FIG. 26 on the object surface. The function of this optical system is the same as in Fig. 25.

In the following, the numerical data of the optical parts 56 as shown in FIG. 24 and FIG. 25 (a) and (b) the bil, and of parts which are arranged in the vicinity thereof, indicated the illumination system.

In the above data, D1-D3 represent lens distances when the magnification is changed by the zoom lens unit 77 of Fig. 24 or Figs. 25 (a) and (b) and the focusing lens 78 is moved according to the working distance (WD) by to determine the lighting position of the lighting system 56 . Table 5 shows the values of the working distances and lens distances.

Table 5

In the following, the numerical data of optical parts, such as the lighting system 56 of FIGS. 26 and 27 (a) and (b) and of parts which are arranged adjacent thereto, are given.

The condenser system 72 can be formed by a lens unit which has the following data.

In the above data represent D1-D4 lens distances when the magnification changed by the zoom lens unit 77 of FIG. 26 or FIG. 27 (a) and (b) and the focusing lens 78 in accordance with the Ar beitsdistanz (WD) is moved. Table 6 shows the values of the working distances and lens distances.

Table 6

As stated above, the wedge-shaped beam splitter 57 is arranged below the lighting system 56 in such a way that its wedge surfaces are continuously directed toward the object surface. Illumination light from the illumination system is transmitted through the beam splitter 57 and reaches the object surface, cf. Fig. 28. The Ligh ting light is reflected by the object surface and But, performed by wide rer reflection by a first surface 57 a of the beam splitter 57 through the observation system 60, to form a Beabachtungsbild. However, part of the light passes through the first surface 57 a. Such light is reflected by a second surface 57 b of the beam splitter 57 and also enters the observation system 60 as secondary light.

However, the beam splitter 57 is wedge-shaped and arranged so that the upper end, tapered by both sides, is directed against the object surface (on the underside of FIG. 28). Therefore, in addition to light, as can be seen in FIG. 28, it can be directed at an angle against the lower part of the microscope body and prevented from entering the observation system 60 and the illumination area of the object surface. The light transmitted by the illumination system via the beam splitter 57 does not fall perpendicularly onto the object surface, but rather obliquely to an extent that observations are not obstructed. Since the beam splitter 57 is formed in a wedge shape, there is no problem that illuminating light, when transmitted through the beam splitter 57 , is refracted and causes a shift between its optical axis and the optical axis for the observation deflected by the beam splitter 57 . The construction is thus such that the prism 80 which forms the illumination system 56 is provided with a refractive power and the optical axis for illumination coincides with the optical axis for observation on the object surface.

In addition, the shape of the illuminating area of the illuminating light transmitted through the wedge-shaped beam splitter 57 does not become circular on the object surface. However, the shape of the observation area is circular, and therefore it is desirable that the shape of the lighting area is circular. By the refractive power of the prism 80 , which forms the lighting system 56 , a correction is carried out so that the shape of the lighting area becomes circular when the illuminating light, which is transmitted through the prism 80 , reaches the object surface through the beam splitter 57 . Therefore, the wedge-shaped beam splitter 57 can be used without any problems.

As mentioned, the light absorption plate 58 is arranged close to the beam splitter 57 . The light absorption plate 58 is provided for absorbing reflected light of the illuminating light from the lighting system 56 , which is not transmitted through the beam splitter 57 , but is reflected to avoid light that can enter the observation system 60 as a secondary light. The light absorption plate 58 according to FIG. 29 is inclined slightly downwards and is arranged close to the beam splitter 57 . It has the function that the light from the lighting system 56 , which is reflected by the beam splitter 57 , is absorbed or reflected and is directed at an angle against the lower part of the microscope body, so that the light does not affect the observation system 60 and the Object surface reached.

According to Fig. 30 (a) light 90 may be a of the illumination light 90 produced by the illumination system through the second surface 57 of the beam splitter 57 b transmit and after it area by the first shell 57 a reflected further by the second surface 57 b of the beam splitter 57 emerges. Of course, the light 90 a reaches the light absorption plate 58 . If the angle of incidence of the light 90 a on the light absorption plate 58 is 90 °, light 90 a 'is generated from the light 90 a by reflection on the light absorption plate 58 and transmitted through the beam splitter 57 and directly directed to the observation system. Since the optical axes of the lighting and observation are coaxial, the light 90 a 'runs parallel to the optical axis of the observation device in order to enter the observation system and form harmful reflex light there. To avoid this, it is necessary that the arrangement is made so that the light 90 a ', which is responsible for the reflected light, is not parallel to the optical axis of the observation.

According to Fig. 30 (b), the light absorbing plate 58 arranged so that the angle of incidence θ of the light 90a on the Lichtab sorptiansplatte 58 is smaller than 90 ° and therefore, the above error will rigiert kor. To completely avoid that light 90 a ', which is responsible for reflected light, enters the observation system, it is expedient that the light absorption plate 58 is arranged so that the angle of incidence of the light 90 a on the light absorption plate 58 is 68.5 ° , see. Fig. 30 (c). To arrange the light absorption plate 58 , it can be constructed as a smooth flat plate, but a curved plate is preferred instead of a flat plate because the curved plate is capable of enhancing a side light-off effect and improving the compactness of the microscope body.

Finally, since such a microscope is used in an operation under difficult sanitary conditions, it is necessary that the microscope is sterilized at a high temperature. For this reason, the transparent plate 59 with high temperature resistance is arranged parallel to the bottom of the microscope body in order to hermetically seal it. The use of the transparent plate 59 prevents dust and the like from entering the microscope body.

As mentioned, the illuminating light falls somewhat obliquely onto the object surface through the beam splitter 57 . If the transparent plate 59 is arranged parallel to the bottom of the microscope body, as shown in FIG. 31, the illuminating light will fall onto the transparent plate 59 somewhat obliquely. As a result, the illuminating light generates reflected light on the transparent plate 59 , however, as shown in FIG. 31, this light is still reflected by the beam splitter 57 and directed at an angle against the lower region of the microscope body. In this way, the observation system 60 and the lighting area are not adversely affected by reflected light.

In the above embodiments, r₁, r₂. . . Krüm Mung radii of individual lens surfaces, d₁, d₂. . . Thicknesses of indivi duel lenses or distances between them, n₁, n₂. . . Refractive indices individual lenses, ₁, ₂. . . Abbe's numbers from individual Lenses, while A is the diameter of the aperture for adjusting the stereoscopic sensitivity, a the diameter of the aperture diaphragm, L the distance from a surface, closest to the image, of the variable System to the center of the aperture diaphragm (the amount of shift) and FN represents the number of fields.

Claims (9)

1. stereomicroscope with an objective lens ( 31 ), a variable magnification system ( 33 ), which has at least one pixel (I) therein and is arranged coaxially to the objective lens ( 31 ), and a pair of observation systems with bilateral symmetry following the magnification system ( 33 ), the aperture diaphragms ( 34 L, 34 R), imaging lenses ( 35 L, 35 R) and eyepieces ( 36 L, 36 R) comprise, with the pair of aperture diaphragms ( 34 L, 34 R) certain optical axes the observation systems run through locations that differ from the optical axis of the magnification system ( 33 ), characterized in that a light shield ( 32 ) at least at the highest magnification set the outside and / or at least at the lowest magnification set the inside of the Pupil of an image covering the center of the field, determined by the pair of apertures ( 34 L, 34 R) on the object side of the pixel (I) mt will. 2. Stereo microscope according to claim 1, characterized in that an enlargement in which the area of the pupil by at least 30% is reduced, is provided. 3. Stereomicroscope according to claim 1 or 2, characterized in that a device for splitting a light beam which emerges from the magnification system ( 33 ) is provided for observations by several observers, the observation images for each observer through the pair of aperture diaphragms ( 34 L, 34 R) are not covered. 4. Stereomicroscope according to claim 3, characterized in that that the relationship between the darkest and lightest areas in lateral cher direction of each observation image is within 1: 3. 5. Stereomicroscope according to one of claims 1 to 4, characterized in that at least four reflecting surfaces are provided in order to have an optical axis close to an optical axis with respect to the exit from the magnification system ( 33 ). 6. Stereomicroscope according to claim 5, characterized in that the magnification system ( 33 ) is afocal. 7. Stereomicroscope according to claim 6, characterized in that that the magnification system is an afocal variable magnification system and an afocal system for forming an image once. 8. A stereomicroscope according to claim 7, characterized in that the magnification system ( 33 ) has a light splitting element ( 46 ; 47 ) for splitting a light beam corresponding to different wavelengths in an afocal system. 9. Stereomicroscope according to one of claims 1 to 9, characterized in that afocal variable magnification systems ( 45 L, 45 R) are arranged on the entrance side of the imaging lenses ( 35 L, 35 R).