JP4742373B2 - Imaging optics and lens barrel - Google Patents

Description

The present invention provides different magnifications by, for example, converting a photographing optical system used to re-image an object image formed by a microscope objective lens on an image sensor, or a plurality of optical systems having different imaging magnifications. The present invention relates to a photographing optical system used for re-imaging, and a lens barrel including these optical systems.

In recent years, an image sensor such as a CCD is often used as a means for observing and photographing a specimen, and applications using a microscope equipped with the image sensor are diversified.

For example, in observing cells in a brain section, infrared light having a wavelength range of 700 nm to 1200 nm with little internal scattering and good transparency is used to observe the internal state of the cells. However, since infrared light cannot be observed by the human eye, the above-described image sensor is used, and an image of a specimen is displayed on a television monitor for observation.

In addition, since the specimen is almost transparent, observation by differential interference is performed. Also in this case, the output signal from the image sensor is electrically processed to enhance the contrast and observe the cell structure as a good contrast image.

In addition, for observation of the brain as described above, a manipulator is operated to have a diameter of several μm.
A patch clamp method is widely used in which a small glass electrode of a certain degree is brought into close contact with the cell membrane surface to examine the electrical characteristics of the Ca ion channel of the cell membrane.

When observation is performed using an imaging device as described above, a sample image is formed on the imaging device using an imaging optical system. As an example of this imaging optical system, Japanese Patent Laid-Open No. 5-1192
There are optical systems described in JP 65, JP 6-281865 A, JP 10-62692 A, and the like. These conventional optical systems have magnifications of about 2 to 5 times, which are relatively high. In addition, a low-magnification photographic optical system or a magnifying lens for television photography is known which constitutes a photographic optical system of about 0.25 to 4 times in combination with an imaging lens.

Further, as an optical apparatus provided with both an optical system that can be observed at a low magnification and an optical system that can be observed at a high magnification, JP-A-8-190056 and JP-A-11-183124.
An apparatus described in the Japanese Patent Publication is known.

Observation with a microscope is performed by performing observation in a wide field of view with a low-magnification objective lens to find the position of the specimen, and enlarging cells using the high-magnification objective lens to perform specimen manipulation and fluorescence observation. The change of magnification at the time of observation is performed by exchanging the objective lens. The replacement of the objective lens is performed by rotating the revolver or sliding the slide mechanism. At that time, an impact occurs. Therefore, the specimen may move out of the field of view. Further, in the above-described patch clamp method, the fine glass electrode may be separated from the cell membrane surface.

In the patch clamp method, when the minute glass electrode is separated, the minute glass electrode must be brought into close contact with the cell membrane surface again, resulting in poor workability.

As a method for converting the magnification without replacing the objective lens, there is a method for replacing the imaging optical system. However, usually only one photographing optical system having a preset magnification is provided in the lens barrel. Therefore, in order to change to various magnifications,
It is necessary to remove the lens barrel from the microscope main body and attach another lens barrel provided with an optical system with a desired other magnification. However, there is a risk of vibration and impact when the lens barrel is replaced.

Further, the apparatus described in the above Japanese Patent Laid-Open Nos. 8-190056 and 11-183124 has a configuration that does not generate vibration or impact when the lens barrel is replaced as described above. However, there is a drawback that the apparatus becomes large.

Also, when differential contrast observation using infrared light electrically enhances contrast, the difference in brightness increases when a low-magnification shooting optical system and a high-magnification shooting optical system are exchanged. There are drawbacks.

Furthermore, when contrast is enhanced by amplifying the image signal in differential interference observation using infrared light or the like, if there is flare light, the flare light is also enhanced even if the brightness is slight, so the image contrast deteriorates. .

The present invention provides a photographing optical system capable of obtaining good optical performance within a predetermined magnification range.

The present invention also provides an optical system capable of converting a magnification with less vibration and impact, and a lens barrel including the optical system.

The present invention also provides a photographing optical system that suppresses the generation of flare light as much as possible.

A first configuration of the photographing optical system of the present invention is an optical system used in a microscope including an objective lens and an imaging lens, and includes a first lens group including a positive cemented lens including a positive lens and a negative lens; A second lens group including a negative cemented meniscus lens having a concave surface facing the first lens group; and a third lens group including a cemented lens; and between the first lens group and the second lens group To form an intermediate image, and the following condition (1
) And (2) are satisfied.

(1) 0.25 ≦ F / FO ≦ 1.5
(2) 0.15 ≦ D1 / D ≦ 0.4
Where F is the focal length of the optical system from the imaging lens to the third lens group, FO is the focal length of the imaging lens, and D1 is the intermediate lens surface from the rearmost lens surface of the first lens group. The distance to the image position, D, is the distance from the frontmost lens surface of the imaging lens to the rearmost lens surface of the third lens group.

In a microscope provided with an infinite correction type objective lens, the light beam emitted from the objective lens is an infinite light beam. Therefore, this is converted into a convergent light beam by the imaging lens. The first configuration of the photographing optical system of the present invention is the one converted into the convergent light beam,
Incident on the first lens group including a positive cemented lens composed of a positive lens and a negative lens,
The first lens group is configured to form an intermediate image. A final image is formed by the second lens group having a negative cemented meniscus lens having a concave surface facing the first lens group, that is, the concave surface facing the intermediate image, and the third lens group including the cemented lens. It is configured as follows. The total refractive power of each of the first to third lens groups is positive refractive power, negative refractive power, and positive refractive power.

In addition, this first configuration makes it possible to form an image having good imaging performance at a magnification in the range of 0.25 to 1.5 times by satisfying the condition (1). .

In this first configuration, the axial ray height is highest in the third lens group, and the off-axis principal ray height is highest in the first lens group.

In the first configuration, the second lens group close to the intermediate image position has a negative refractive power so as to reduce the Petzval sum and improve the flatness of the image surface. In addition, the forefront lens surface of the second lens group is shaped to have a concave surface facing the intermediate image, thereby suppressing the occurrence of various aberrations. Then, spherical aberration and coma aberration in opposite directions are generated in the second lens group and the third lens group, and both aberrations are corrected well by canceling out these aberrations.

Further, the axial chromatic aberration and the chromatic aberration of magnification are corrected so that each lens group of the first, second, and third lens groups includes a cemented lens.

When the lower limit of the condition (1) is exceeded, the photographing magnification becomes low. In this case, the off-axis chief ray height becomes high, and it is difficult to correct off-axis coma well and to maintain the flatness of the image plane. In addition, it becomes difficult to secure the peripheral light amount. This is because the range that can be observed with the objective lens is widened when the photographing magnification is low, but vignetting or the like occurs in the off-axis light beam at this time.

If the upper limit of the condition (1) is exceeded, the magnification from the intermediate image position to the final image position becomes high, so the second lens group becomes too close to the intermediate image position. As a result, it becomes difficult to construct a photographing optical system having a desired magnification while keeping the distance from the photographing optical system to the final image at a predetermined value. Conversely, if a desired magnification is obtained, the distance from the photographing optical system to the final image becomes too long.

Further, in the first configuration, if the condition (2) is satisfied, the interval from the intermediate image to the final image in the photographing optical system can be set to an appropriate distance. Therefore, the second lens group and the third lens group can be arranged without difficulty between the intermediate image and the final image, and an imaging optical system having a magnification within the range defined in the condition (1), that is, An imaging optical system having a magnification in the range of 0.25 to 1.5 times can be configured. In addition, the photographing optical system can be a zoom optical system by changing the distance between the second lens group and the third lens group.

When the lower limit of condition (2) is exceeded, the distance from the first lens group to the intermediate image is shorter than the distance from the imaging lens to the rear end of the third lens group, and the first lens group has a strong refractive power. Will have to. This makes it difficult to correct aberrations in the intermediate image. Further, the incident angle of off-axis rays to the second lens group is increased, and the incident angle of off-axis rays to the third lens group is further increased by the diverging action of the second lens group. Therefore, it is necessary to give the third lens group a strong positive refractive power, and it becomes difficult to correct the optical performance well. By making the refractive power of the second lens group weak, it is possible to reduce the incident angle to the third lens group. However, the Petzval sum is increased, image surface flatness is deteriorated, and the magnification range of the photographing optical system is narrowed.

When the upper limit of the condition (2) is exceeded, the distance from the first lens group to the intermediate image becomes larger than the distance from the imaging lens to the rear end of the third lens group, and the intermediate image position to the final image position. The interval until is small. As a result, aberration correction becomes difficult, and the condition (1
) Magnification range is narrowed. In addition, it becomes difficult to reduce the incident angle of the chief ray at the final image position. Therefore, if an image sensor such as a CCD is disposed at the final image position, shading or the like peculiar to the image sensor occurs, which is not preferable.

Next, a second configuration of the photographing optical system according to the present invention is an optical system used in a microscope having an objective lens and an imaging lens, and includes a first lens group including a positive cemented lens composed of a positive lens and a negative lens. And a second lens including a positive lens having a convex surface facing the first lens group.
A third lens group including a lens group and a cemented lens, and configured to form an intermediate image between the first lens group and the second lens group, and the following conditions (3), (4)
Is satisfied.

(3) 1.8 ≦ F ′ / FO ≦ 2.5
(4) 0.15 ≦ D2 / D ′ ≦ 0.4
Where F ′ is the focal length of the imaging optical system from the imaging lens to the third lens group, FO is the focal length of the imaging lens, and D2 is from the lens surface at the rearmost side of the first lens. The distance to the intermediate image position, D ′, is the distance from the frontmost lens surface of the imaging lens to the rearmost lens surface of the third lens group.

As described above, the light beam emitted from the objective lens becomes an infinite light beam, enters the imaging lens, and is converted into a convergent light beam. According to the second configuration of the photographing optical system of the present invention, the convergent light beam converted in this way is incident on a first lens group having a positive cemented lens composed of a positive lens and a negative lens. An intermediate image is formed by the group. This intermediate image is formed as a final image by the second lens group including a positive lens having a convex surface directed to the intermediate image and the third lens group including a cemented lens. The total refractive power of each of the first to third lens groups is positive refractive power, positive refractive power, and positive refractive power.

This second configuration has the above lens configuration and satisfies the condition (3), so that good imaging performance is obtained in the range of 1.8 times to 2.5 times which is a higher magnification than the first configuration. It is comprised so that it may be obtained.

In this second configuration, the on-axis ray height is highest in the imaging lens, and the off-axis chief ray is highest in the third lens group.

In the second configuration, the second lens group close to the intermediate image position has a positive refractive power, and the second lens group functions as a third lens group and a field lens that adjusts the incident angle at the final image position. Is given. Further, by using a cemented lens for each lens group, the Petzval sum can be kept small, and axial chromatic aberration and lateral chromatic aberration can be corrected well.

In the second configuration, the forefront lens surface of the second lens group is directed toward the intermediate image so that flare light generated in the second lens group is suppressed. In general, the lens surface of the meniscus lens is susceptible to flare because of its weak power to refract light. Therefore, when the second lens group has a meniscus shape with the concave surface facing the intermediate image side, the light reflected by the third lens group side surface of the second lens group is reflected by the surface of the intermediate image side and flare light. And the final image position is reached. Therefore, if an image sensor is arranged at the final image position, an image with flare is captured. Moreover, the intensity of the flare light becomes so large that it cannot be ignored when the electrical contrast is enhanced. For example, differential interference observation using infrared light is not preferable because it leads to deterioration of contrast and generation of spot flare light.

Further, flare light may be generated not only between the two lens surfaces in the second lens group but also between the lens surfaces of other lens groups. From the above, it is important to make the foremost lens surface of the second lens group convex to the intermediate image. Further, it is desirable that the second lens group be a biconvex cemented lens.

When the lower limit of the condition (3) is exceeded, the photographing magnification becomes low. In this case, the off-axis chief ray height is increased, and off-axis coma and astigmatism are deteriorated.

If the upper limit of the condition (3) is exceeded, the magnification from the intermediate image position to the final image position increases, and the second lens group becomes too close to the intermediate image position. As a result, it becomes difficult to construct a photographing optical system having a desired magnification while keeping the distance from the photographing optical system to the final image at a predetermined value. Conversely, when trying to obtain a desired magnification, the distance to the final image becomes too long.

Condition (4) is a condition for making an appropriate distance from the intermediate image position of the photographing optical system to the final image. Therefore, by satisfying this condition (4),
The second lens group and the third lens group can be reasonably arranged between the intermediate image and the final image, and a photographing optical system having a magnification within the range defined in the condition (3), that is, 1.8. It is possible to construct a photographic optical system in the range of double to 2.5 times. It is also possible to make a zoom lens by changing the distance between the second and third lens groups and the third lens group.

When the lower limit of condition (4) is exceeded, the distance from the first lens group to the intermediate image becomes shorter than the distance from the imaging lens to the rear end of the third lens group, and the first lens has a strong refractive power. I will have to let it. Therefore, the spherical aberration in the intermediate image deteriorates,
The subsequent lens group cannot be corrected satisfactorily. In addition, the incident angle of the axial ray on the second lens group becomes large, and it becomes difficult to correct spherical aberration and off-axis chromatic aberration in the second lens group and the third lens group.

When the upper limit of condition (4) is exceeded, the distance from the first lens group to the intermediate image becomes longer than the distance from the imaging lens to the rear end of the third lens group, and the distance from the intermediate image position to the final image is increased. Becomes shorter. As a result, aberration correction becomes difficult. In addition, it becomes difficult to reduce the incident angle of the incident principal ray at the final image position. Therefore, it is not preferable to place an image sensor such as a CCD at the final image position because shading or the like peculiar to the image sensor occurs.

A third configuration of the photographing optical system of the present invention is an optical system used for a microscope including an objective lens and an imaging lens, and includes a first lens group including a positive cemented lens including a positive lens and a negative lens, A second lens group including a negative cemented lens composed of a positive lens and a negative lens, and a third lens group including a positive cemented lens composed of a positive lens and a negative lens;
A fourth lens group including a positive lens having a convex surface facing the third lens group, and an intermediate image is formed between the third lens group and the fourth lens group;
The following condition (5) is satisfied.

(5) 3 ≦ F ″ / FO ≦ 6
Where F ″ is the focal length of the optical system from the imaging lens to the fourth lens group, and FO is the focal length of the imaging lens.

In the third configuration of the photographing optical system of the present invention, an intermediate image is formed by the optical system from the imaging lens to the third lens group, and this image is formed by the fourth lens group. Further, by satisfying the condition (5), it is possible to construct a photographic optical system having a magnification of 3 times or more, which is a higher magnification.

The third configuration is an optical system having a high magnification. Therefore, for example, the observation image becomes darker than the low magnification optical system as in the first configuration, and it is necessary to sufficiently reduce the intensity of flare light generated in the photographing optical system.

In the third configuration, a field stop is disposed in the intermediate image, and the light is generated in an optical system from the imaging lens to the intermediate image (an optical system including the imaging lens, the first, second, and third lens groups). I try to suppress flare. In addition, flare light is suppressed by reducing the number of air contact surfaces with high reflectivity. For this reason, only the fourth lens group is used from the intermediate image to the final image.

Further, in the third configuration, the convergent light beam that has passed through the first lens unit having the positive refractive power is diverged by the second lens unit having the negative refractive power, and the third lens group having the positive refractive power is more appropriate. An intermediate image was formed at the position. A final image is formed by the fourth lens unit having a positive refractive power. Further, due to the negative refractive power of the second lens group, the Petzval sum was reduced to improve the image surface flatness. Further, the spherical aberration and coma aberration generated in the second lens group are generated in the opposite direction to the spherical aberration and coma aberration generated in the third lens group and the fourth lens group, and these aberrations cancel each other. Is corrected well.

The third lens group is disposed near the intermediate image and acts as a field lens. When the surface of the third lens group on the intermediate image side is a convex surface with respect to the intermediate image, and the image pickup device is arranged at the final image position, the lens surface in the third lens group and the surface of the image pickup device are generated. The intensity of flare light and the intensity of flare generated on the lens surface in the third lens group and the lens surfaces in the other lens groups are suppressed to a low level.

When the third lens group is formed in a meniscus shape with a concave surface facing the intermediate image side, the reflected light from the two air contact surfaces of the third lens group and the reflected light from the surface of the imaging element are reflected on the meniscus of the third lens group. It is reflected by the lens surfaces before and after the shape and reaches the final image position. As a result, strong flare light and spot flare are generated. Therefore, as in the third configuration, the intensity of flare generated in the photographing optical system is reduced, and good optical performance is obtained.

Next, the condition (5) will be described. When the lower limit of the condition (5) is exceeded, the ratio of the focal length of the photographing optical system to the imaging lens becomes small, and the photographing range becomes wide.
As a result, off-axis coma and astigmatism deteriorate. In addition, the numerical aperture of incident light at the final image position becomes large, and it becomes difficult to correct spherical aberration.

When the upper limit of the condition (5) is exceeded, the ratio of the focal length of the photographing optical system to the imaging lens increases, and the magnification for relaying the intermediate image to the final image by the fourth lens group increases. As a result, the distance from the intermediate image to the fourth lens group becomes short, and it becomes impossible to construct a photographing optical system having a desired magnification while keeping the distance from the photographing optical system to the image pickup device at a predetermined value. Although it is conceivable to divide the fourth lens group into two parts and to increase the magnification by configuring the two lens groups, the number of lens surfaces in contact with the air in the fourth lens group increases, and flare light increases. Is likely to occur. Thus, considering the increase in the possibility of occurrence of flare light, a method of realizing a photographing optical system having a desired high magnification by forming the fourth lens group as a plurality of groups is not preferable.

The fourth configuration of the photographing optical system of the present invention is an optical system used in a microscope having an objective lens and an imaging lens, and is inserted into the optical path and a fixed group that is always fixed in the optical path of the optical system. The fixed group includes a first lens group including a positive cemented lens including a positive lens and a negative lens, and the moving group includes the first moving group and the second moving group. The first moving group includes a second lens group including a negative cemented meniscus lens having a concave surface facing the fixed group side, and a third lens group including a cemented lens. An intermediate image is formed between the lens group and the second lens group, and the second moving group includes a second lens including a positive lens having a convex surface facing the first lens group.
A lens group and a third lens group including a cemented lens, wherein an intermediate image is formed between the first lens group and the second lens group, and the first moving group and the An optical system that converts the magnification by converting the second moving group,
The optical system having the fixed group and the first moving group satisfies the following conditions (1) and (2), and the optical system having the fixed group and the second moving group has the following conditions (3) and (4). Is satisfied.

(1) 0.25 ≦ F / FO ≦ 1.5
(2) 0.15 ≦ D1 / D ≦ 0.4
(3) 1.8 ≦ F ′ / FO ≦ 2.5
(4) 0.15 ≦ D2 / D ′ ≦ 0.4
Where F is the focal length of the optical system from the imaging lens to the third lens group of the photographic optical system having the first moving group, and F ′ has the second moving group from the imaging lens. The focal length of the optical system to the third lens group of the photographing optical system, FO is the focal length of the imaging lens, D1 is the rearmost side of the first lens group in the photographing optical system having the first moving group. The distance from the lens surface to the intermediate image position, D2
Is the distance from the rearmost lens surface of the first lens group to the intermediate image position in the photographing optical system having the second moving group, and D is the first lens surface from the frontmost lens surface of the imaging lens. The distance from the lens surface which is the rearmost side of the third lens group of the imaging optical system having one moving group to the rearmost lens surface, D ′ has the second moving group from the lens surface which is the frontmost side of the imaging lens. This is the distance to the rearmost lens surface of the third lens group of the photographing optical system.

According to a fourth configuration of the photographing optical system of the present invention, a final image is formed by arranging a plurality of moving groups different from the common fixed group from the imaging lens side behind the microscope including the objective lens and the imaging lens. Is. By changing this moving group to one with a different magnification, conversion of magnification from low magnification (0.25 to 1.5 times) to medium magnification (1.8 to 2.5 times) was made possible. It is characterized by that.

In other words, the fourth configuration includes the imaging lens and the first lens closer to the objective lens than the intermediate image.
These lens groups become a common fixed group. A plurality of lens groups behind the first lens group are prepared as moving groups. In the fourth configuration, the first moving group and the second moving group, which are moving groups having different focal lengths, can be inserted into and removed from the optical path, and the optical formed by the fixed group and the moving group by exchanging the moving group. The focal length of the system (hereinafter referred to as the photographing unit) is converted. In this way, the magnification is converted by changing the ratio between the focal length of the imaging lens and the focal length of the photographing unit.

The fourth configuration is the first and second configurations of the photographing optical system of the present invention described above.
The lens group is a common fixed group, and the other lens groups after the second lens group are each a moving group. That is, when the first and second lens groups in the first configuration and the second configuration are the first, second, and third moving groups, respectively, a low-magnification photographing unit is formed by the fixed group and the first moving group. An imaging unit with an intermediate magnification is configured by the fixed group and the second moving group. That is, a plurality of photographing optical systems with different magnifications can be realized by exchanging only the first and second moving groups as described above.

In this fourth configuration, by exchanging the first movement group and the second movement group,
An imaging optical system capable of converting the magnification between a low magnification (0.25 to 1.5 times) and an intermediate magnification (1.8 to 2.5 times). For example, the objective lens has a magnification of 20 and a numerical aperture of 0
. 9 and the ratio of the focal lengths of the two photographing units to the imaging lens is 0.2.
With 5 and 2.5, the magnification from the objective lens to the final image position is 5 times on the low magnification side and 50 times on the intermediate magnification side. Without changing the objective lens in this way,
It is possible to change the photographing magnification greatly.

In the fourth configuration, a part of the lens groups of the photographing unit is a common fixed group, and only the other lens groups are exchanged, so that the exchange mechanism can be downsized. Moreover, the exchange mechanism can be simplified. From these facts, the cost can be reduced.

In addition, a half mirror can be disposed on the exit side of the imaging lens, and an imaging unit can be disposed on the optical path on the side reflected by the half mirror. At this time, the reflecting surface of the half mirror is directed in the depth direction of the microscope body. In this way, the imaging unit can be arranged at a position away from the specimen. That is, the moving group that is a source of vibration and impact during zooming can be moved away from the specimen. And
As described above, some lens groups of the photographing unit are inserted into and removed from the optical path when the magnification is converted. Therefore, by making the main body of the microscope a structure that suppresses vibrations and shocks that occur when the lens group is inserted and removed, or by preventing the vibrations and shocks from being transmitted, these vibrations and shocks are applied to the specimen. It is possible not to be transmitted.

Thus, according to the 4th structure of this invention, it is possible to reduce a vibration and an impact at the time of magnification conversion. Therefore, even if the magnification is changed during observation by the patch clamp method, it is possible to prevent the specimen from moving out of the field of view due to vibration, impact, or the like, or the minute glass electrode from moving away from the specimen.

Further, since the objective lens is not exchanged, the manipulator is not accidentally touched when the objective lens is exchanged, and workability and operability are improved.

5 shows a fifth configuration of the photographing optical system of the present invention.
An optical system used in a microscope comprising an objective lens and an imaging lens, comprising a fixed group that is always fixed in the optical path of the optical system, and a moving group that can be inserted into and removed from the optical path, and the fixed group Has a first lens group including a positive cemented lens composed of a positive lens and a negative lens, and the moving group has a first moving group and a third moving group, and the first moving group is A second lens group including a negative cemented meniscus lens having a concave surface facing the fixed group side; and a third lens group including a cemented lens; and an intermediate image between the first lens group and the second lens group. The moving group of the third group includes a second cemented lens including a negative cemented lens including a positive lens and a negative lens, and a positive cemented lens including a positive lens and a negative lens. A third lens group and a positive lens including a positive lens having a convex surface facing the third lens group. And converting the first moving group and the third moving group configured to form an intermediate image between the third lens group and the fourth lens group. The optical system having the magnification converted by the optical system having the fixed group and the first moving group has the following conditions (1) and (2), and has the fixed group and the third moving group: The optical system satisfies the following condition (5).

(1) 0.25 ≦ F / FO ≦ 1.5
(2) 0.15 ≦ D1 / D ≦ 0.4
(5) 3 ≦ F ″ / FO ≦ 6
Where F is the focal length of the optical system from the imaging lens to the third lens group of the photographing optical system having the first moving group, and F ″ has the third moving group from the imaging lens. The focal length of the optical system to the fourth lens group of the photographing optical system, FO is the focal length of the imaging lens, D1 is the rearmost side of the first lens group in the photographing optical system having the first moving group. The distance from the lens surface to the intermediate image position, D is the lens on the rearmost side of the third lens group of the photographing optical system having the first moving group from the lens surface on the frontmost side of the imaging lens The distance to the surface.

In the fifth configuration, the optical system behind the imaging lens includes a fixed group and a moving group, and the fixed group includes a first lens group including a positive cemented lens including a positive lens and a negative lens. The first configuration is similar to the above-described fourth configuration in that the first moving group includes a second lens group having a negative cemented meniscus lens having a concave surface facing the fixed group and a third lens group having a cemented lens. . In the fifth configuration, the first moving group is replaced with a second lens group including a negative cemented lens in which a positive lens and a negative lens are cemented, and a positive cemented lens in which a positive lens and a negative lens are cemented. The third moving group includes a third lens group including a lens and a fourth lens group including a lens having a convex surface directed toward the third lens group. Then, the low magnification (0.25 to 1) is obtained by exchanging the first moving group and the third moving group.
. 5 times) and high magnification (3 to 6 times). In other words, the fifth configuration realizes a configuration corresponding to the imaging optical system of the first configuration and a configuration corresponding to the imaging optical system of the third configuration by exchanging the first and third moving groups. ing.

    Next, the lens barrel of the present invention will be described.

The lens barrel of the present invention is a lens barrel used in a microscope having an objective lens and an imaging lens, and includes a first lens group including a positive cemented lens composed of a positive lens and a negative lens, and the first lens group. A second lens group including a negative cemented meniscus lens having a concave surface facing the side, and a third lens group including a cemented lens, and forming an intermediate image between the first lens group and the second lens group And a photographic optical system that satisfies the following conditions (1) and (2).

(1) 0.25 ≦ F / FO ≦ 1.5
(2) 0.15 ≦ D1 / D ≦ 0.4
Where F is the focal length of the optical system from the imaging lens to the third lens group, FO is the focal length of the imaging lens, and D1 is the intermediate image from the lens surface at the rearmost side of the first lens. The distance to the position, D, is the distance from the frontmost lens surface of the imaging lens to the rearmost lens surface of the third lens group.

The lens barrel of the present invention is used for a microscope having an objective lens and an imaging lens. The lens barrel of the present invention is arranged on the exit side of the imaging lens and has the first configuration of the photographing optical system of the present invention. Therefore, it is possible to realize a lens barrel capable of obtaining good imaging performance at a magnification in the range of 0.25 to 1.5 times. Further, a half mirror which is an optical path dividing element is arranged, and an optical system having the first configuration of the photographing optical system of the present invention is provided in an optical path where light is reflected by the optical path dividing element (hereinafter referred to as a reflection side optical path). May be arranged.
Then, an observation barrel having an eyepiece optical system can be arranged in an optical path through which light has passed through the optical path dividing element (hereinafter referred to as a transmission side optical path), and visual observation can be performed. Further, another second optical path splitting element such as a half mirror or a half prism can be arranged between the optical path splitting element and the observation barrel. With such a configuration, it becomes possible to arrange the second imaging optical systems having different magnifications in one of the optical paths divided by the second optical path splitting element. As a result, photographing at two different magnifications by the second photographing optical system and the photographing optical system having the first configuration and observation by the eyepiece lens are possible. At this time, if the lens barrel is integrated with two imaging optical systems and an observation optical system having an eyepiece, the lens barrel can be made compact and the operability is improved.

Note that the second imaging optical system can be arranged in the optical path of the light beam that has passed through the optical path splitting element without providing an observation barrel. If a photographic optical system that reduces or enlarges an image with an imaging lens is disposed as the second photographic optical system, an object can be taken with a reduced image or an enlarged image. Further, the second photographic optical system can be replaced with a photographic optical system having a different magnification, and photographing with a converted magnification can be performed.

In the lens barrel of the present invention, a photographic optical system having the second configuration may be arranged instead of the photographic optical system having the first configuration. As a result, it is possible to realize a lens barrel having a good imaging performance within a magnification range of 1.8 to 2.5. In this case, a plurality of photographing and observation as described above can be performed by further disposing the optical path dividing element in the lens barrel.

In the lens barrel of the present invention, the third configuration of the photographic optical system of the present invention is arranged in place of the photographic optical system of the first configuration, so that the magnification is good within a range of 3 to 6 times. A lens barrel having imaging performance can be realized. In this case, an optical path splitting element may be further arranged in the lens barrel.

The optical system arranged in the second photographing optical system may have the first to third configurations, but may be another optical system that is completely different from these configurations.

In the lens barrel of the present invention, the fourth configuration of the photographic optical system of the present invention may be arranged instead of the photographic optical system of the first configuration. That is, it is possible to realize a lens barrel capable of converting the magnification by configuring the photographing optical system with a plurality of moving groups different from the fixed group and converting the moving group. Further, by arranging the optical path splitting element, it is possible to realize a lens barrel that enables photographing and observation with different magnifications.

Since this lens barrel is arranged with the fourth configuration of the photographing optical system of the present invention,
By exchanging the moving group, magnification conversion can be performed at a low magnification (for example, 0.25 to 1.5 times) and an intermediate magnification (for example, 1.8 to 2.5 times). In addition, the fifth configuration of the photographing optical system of the present invention can be arranged. In this case, a low magnification (for example, 0.25)
It is possible to shoot at two magnifications, i.e., 1.5 times) and a high magnification (for example, 3-6 times). As a matter of course, if the photographing optical systems having the first, second, and third configurations are arranged together, photographing at three magnifications is possible.

Moreover, as described above, it is possible to suppress the generation and transmission of vibrations and shocks that occur when the magnification is converted by setting the reflecting surface of the optical path splitting element in an appropriate direction.

In the above-described first configuration of the photographing optical system of the present invention and the lens barrel having the first configuration, it is desirable to provide an aperture stop for limiting the numerical aperture of the objective lens in the photographing optical system. In addition, the fourth and fifth configurations of the imaging optical system of the present invention and the lens barrel having these configurations include an imaging unit corresponding to the first configuration. Therefore, it is desirable to provide an aperture stop in this photographing unit even in these configurations.

The first configuration of the photographic optical system of the present invention is a photographic optical system with good imaging performance within a magnification range of 0.25 to 1.8 times. Such a low magnification optical system is
This is used to find the position of an observation object in observation with a microscope. Therefore, since a particularly high resolving power is not required, it is preferable to limit the numerical aperture of the objective lens by arranging an aperture stop at the pupil position of the objective lens or its conjugate position. As a result, the light beam is narrowed to some extent, so that it is possible to use a region in which the aberration is corrected particularly well in the photographing optical system. Therefore, the optical performance is improved. Further, it is possible to improve the unbalance of the light amount at the center of the visual field and the periphery.

In the low-magnification optical system as in the first configuration, the numerical aperture of the light beam incident on the image sensor is very large, so it is necessary to increase the number of lenses and the number of lens groups in the optical system. Therefore, generation of flare light becomes a problem.

However, low-magnification shooting or the like with a microscope is often used mainly to search for the position of an object, the shooting position, and the like. Therefore, there is almost no problem even if the numerical aperture of the objective lens is limited. For this reason, in the first optical imaging system having a low magnification as described above, it is preferable to provide an aperture stop to limit the size of the light beam, thereby generating flare light and removing flare light. . Further, the aperture stop may be configured to change in diameter. Further, the aperture stop may be movable. In this way, the aperture stop can be moved to a position conjugate with the pupil position of the objective lens when the objective lens is replaced with another objective lens.

When the magnification is changed by exchanging the moving group as in the fourth configuration or the fifth configuration of the imaging optical system of the present invention, an aperture stop is arranged in a low-magnification imaging unit, for example, the first moving group. The numerical aperture of the objective lens should be limited.
When the magnification is switched to another magnification, the aperture stop leaves the optical path together with the first moving group, so that it is possible to take an image with the numerical aperture of the objective lens.

Further, as described above, an aperture stop may be disposed in the first configuration of the present invention, and an optical element that attenuates the amount of light, such as an ND filter, may be disposed. An optical element that attenuates the amount of light may be provided in the first moving group having the fourth configuration or the fifth configuration.

Thus, by arranging an optical element that attenuates the amount of light in the low-magnification photographing optical system, when using the photographing optical system of this magnification and when using a photographing optical system of a higher magnification, the final The amount of light at the image position can be made substantially equal. This will be described below.

When the image sensor is arranged at the final image position, the amount of light incident on the image sensor is proportional to the square of the numerical aperture of the light beam incident on the image sensor. For this reason, the amount of light becomes larger when a photographing optical system with a low magnification is used. Therefore, by arranging the optical element for attenuating the amount of light as described above, the amount of light incident on the image sensor can be made substantially equal even when switching between imaging at a low magnification and imaging at a high magnification. Therefore, it is not necessary to adjust the contrast of the image greatly, and the operability is improved.

Further, by combining with an aperture stop that is arranged in the observation optical system on the low magnification side and restricts the numerical aperture, it becomes possible to make the amount of light substantially the same as on the high magnification side while appropriately reducing the resolving power. In addition, by making the optical element that attenuates the amount of light detachable, it is possible to deal with various applications.

When this optical element that attenuates the amount of light is detachably placed in a finite luminous flux,
The imaging position and the magnification change due to the attachment / detachment. In such a case, the imaging position and the magnification can be changed by changing the distance between the second lens group and the third lens group and the distance between the third lens group and the imaging element (final image). At this time, since the aberration hardly changes, the performance of the optical system is not deteriorated.

In the above-described lens barrel of the present invention, it is preferable that the wavelength characteristic of the optical path splitting element is a characteristic that transmits light in the visible region and reflects light in the infrared region.

By providing such wavelength characteristics to the optical path splitting optical element so as to transmit visible light and reflect light in the infrared region, it becomes possible to observe an object simultaneously with different observation methods. For example, consider the case of fluorescence observation. Since the cells or tissues are colorless and transparent, differential interference observation is effective in understanding the whole state. Therefore, when infrared light is used, differential interference observation with infrared light can be performed on the optical path reflected by the optical path splitting element. On the other hand, since visible light passes through the optical path splitting element, fluorescence observation can be performed in this optical path. As described above, for fluorescence observation, observation by the eyepiece optical system and imaging by the second imaging optical system can be performed, and differential interference observation can be performed by the first imaging optical system. Furthermore, by changing the wavelength characteristics of the optical path dividing optical element, it is possible to realize a lens barrel optical system corresponding to a wide range of applications.

In a lens barrel having an optical path dividing element, it is desirable to dispose a polarizing element in the reflection side optical path.

Thus, by arranging the polarizing element in the reflection side optical path, the reflection side optical path can be made a dedicated optical path for polarization observation and differential interference observation. On the other hand, the transmission side optical path can be a dedicated optical path for fluorescence observation and bright field observation. In this way, it is possible to easily cope with various applications in microscopic observation.
Note that it is desirable that the polarizing element is disposed between the optical path splitting element and the intermediate image in order to suppress deterioration of polarization characteristics. However, the position is not necessarily limited to this position, and it is preferable to arrange at the most suitable position according to the application. Further, it is preferable that the polarizing element be insertable / removable. In this case, it is preferable to move at least one of the lens groups on the reflection side optical path along the optical axis because the imaging position and magnification can be corrected. The lens group to be moved is preferably a lens group arranged at a position closest to the final image.

In the lens barrel of the present invention, when the lens barrel is connected to the microscope main body, any one of the first to fifth configurations described above is provided on the reflection side optical path by arranging an optical path dividing element on the optical axis of the objective lens. This photographic optical system is arranged. Further, a light deflecting element for deflecting light emitted from the lens group closest to the final image among the lens groups in the photographing optical system is provided and disposed. When the intersection of the optical axis of the objective lens and the optical path splitting element is P1, and the intersection of the optical axis deflected by the optical deflection element and toward the final image position is P2, the following condition (6) is satisfied. It is desirable to make it so.

(6) 150mm ≦ L ≦ 300mm
However, L is the interval between P1 and P2.

For example, when the desk surface on which the microscope is disposed is used as a reference, the optical axis of the objective lens is perpendicular to the desk surface. The optical path splitting element is located on the optical axis of the objective lens and is arranged so as to reflect a part of the light from the objective lens. Therefore, if the reflecting surface is arranged at 45 ° with respect to the optical axis of the objective lens, the optical axis of the reflection side optical path becomes horizontal with respect to the desk surface. If the first to third imaging optical systems are arranged in the reflection side optical path, it is not necessary to arrange the imaging optical system in a direction perpendicular to the desk surface. It can be kept low. The optical path splitting element is preferably disposed between the imaging lens and the photographing optical system.

Further, in all of the first to third imaging optical systems, the distance from the first lens group to the final image is the same (about 315 mm). The distance from the first lens group to the final lens group (that is, the lens group closest to the final image position side) is about 176 mm to 265 mm. Therefore, if the light deflection element is disposed so as to satisfy the condition (6), the light deflection element is disposed between the final lens group and the final image. If comprised in this way, all the lens groups which comprise the imaging optical system of a 1st structure thru | or a 3rd structure can be arrange | positioned horizontally with respect to a desk surface. Therefore, when the photographing optical system is assembled, the position adjustment of each lens group can be easily performed.
Also, when moving a specific lens group in the optical axis direction, the movement mechanism need not be complicated. Further, when exchanging a part of the lens groups as in the fourth configuration and the fifth configuration, the exchange mechanism need not be complicated.

Further, when the arrangement direction of the photographing optical system is the depth direction of the microscope, the final image is also formed in the depth direction unless the light deflection element is arranged. On the other hand, if the light deflection element is arranged as in the lens barrel of the present invention, the final image is not formed in the depth direction. Therefore, even when the epi-illumination device is attached to the microscope, the light source of the epi-illumination device and the lens barrel do not cause mechanical interference.

Also, the reflection surface of the light deflection element is set so that the optical axis in the optical path after being reflected by the light deflection element (that is, the optical path from the light deflection element to the final image position) is parallel to the desk surface. Then, the final image position becomes the same height as the photographing optical system. on the other hand,
If the reflecting surface of the light deflecting element is set so that the optical axis in the optical path after being reflected by the light deflecting element is in a direction perpendicular to the desk surface, the final image position becomes higher than that of the photographing optical system. However, the height is not so high because it is a position several tens of millimeters higher than the optical axis of the photographing optical system. As described above, even when the final image position is included, the height of the lens barrel can be kept low in the lens barrel of the present invention. Although the description has been given of the lens barrel including the imaging optical system having the first to third configurations, the same applies to the lens barrel including the imaging optical system having the fourth configuration and the fifth configuration.

As described above, in the lens barrel of the present invention, the height of the lens barrel can be kept low by satisfying the condition (6). That is, the photographing optical system is not arranged in a direction perpendicular to the desk surface. Therefore, even if the lens barrel of the present invention is attached to the microscope, the position of the center of gravity can be lowered, so that the entire microscope does not become unstable. As a result, it is possible to configure a microscope that is strong against external vibration and shock. Normally, the light source is arranged in the depth direction of the microscope. However, in the case of the lens barrel of the present invention, the photographing optical system is provided in front of the light source even if the direction of the reflection surface of the optical path dividing element is in the depth direction. Can be placed. Therefore, there is no mechanical interference between the lens barrel and the light source (light source device).

Next, the influence of flare light in the photographing optical system will be described. Usually, the lens surface is coated with an antireflection coating. However, even with such a coating, a slight reflection occurs on the lens surface, that is, the air contact surface. Naturally, the more lenses that make up the optical system, the more such reflections occur. Then, the reflected light generated on the air contact surface is reflected again on another air contact surface and reaches the final image position. Of the light reaching the final image position, light having relatively high light intensity or light condensed to some extent becomes flare light. In particular, an optical system that captures an image with an image sensor is convenient because the captured image can be subjected to image processing such as image enhancement. However, if there is flare light, the flare light is also enhanced. Therefore, it is necessary to suppress the generation of flare light in an optical system that captures an image with an image sensor.

From such a point, it is preferable that the first to third configurations of the photographing optical system of the present invention are configured as follows. In the first configuration, the first lens group includes only one positive cemented lens including a positive lens and a negative lens, and the second lens group includes only one negative cemented meniscus lens having a concave surface facing the first lens group. The third lens group is composed of only one positive cemented lens and one positive single lens. In the second configuration, the first lens group is only one positive cemented lens composed of a positive lens and a negative lens, and the second lens group is one positive cemented lens with a convex surface facing the first lens group. Only the third lens group is composed of one positive cemented lens and one positive single lens. In the third configuration, the first lens group includes only one positive cemented lens including a positive lens and a negative lens, and the second lens group includes only one negative cemented lens including a positive lens and a negative lens. The third lens group includes only one positive cemented lens, and the fourth lens group includes only one positive single lens having a convex surface facing the third lens group.

Thus, by configuring each lens group with only one lens component or only two lens components, the number of flare lights generated on the air contact surface can be suppressed. The lens component is a single lens or a cemented lens. In addition,
The same applies to the fourth configuration, the fifth configuration, or the lens barrel of the present invention.

On the other hand, even if flare light is generated, there is no problem if the light intensity of the flare light is smaller than the light intensity of the original image (sample image). Therefore, in the above-described first to fifth configurations of the photographing optical system of the present invention and the lens barrel of the present invention, it is preferable that the following condition (7) is satisfied.

(7) {(F / (FO) · sin θ} ² ≦ 0.005
Where F is the focal length of the photographic optical system, FO is the focal length of the imaging lens, and θ is reflected to the objective lens side by an arbitrary air contact surface between the objective lens and the final image. The incident angle at the final image position of the axial light beam reflected to the final image side by an air contact surface different from the surface.

The condition (7) is derived from the viewpoint that it is only necessary to suppress the light intensity that does not cause a problem even if flare light is generated. That is, the condition (7) is a condition for suppressing the light intensity of flare light to such an extent that the contrast of the original image is not deteriorated in the first to fifth configurations of the photographing optical system of the present invention. If the condition (7) is satisfied, the light intensity of the flare light generated on the air contact surface before the light from the objective lens reaches the final image position of the photographing optical system can be suppressed. Therefore, even if the image captured using the image sensor is an image in which flare light is superimposed on the entire image or an image in which flare light is locally superimposed (image in which spot flare light is superimposed), It is possible to perform electrical contrast enhancement for such an image, and to make the deterioration of contrast inconspicuous.

Here, whether or not the light intensity of the flare light deteriorates the contrast of the original image depends on the relative magnitude of the light intensity of the original image and the light intensity of the flare light. The higher the photographing magnification β of the photographing optical system (ratio of the focal length of the photographing optical system to the focal length of the imaging lens), the smaller the light intensity of the original image. This is because the numerical aperture of the axial light beam incident on the final image position decreases as the imaging magnification β of the imaging optical system increases. As described above, since the light intensity of the original image relatively decreases as the photographic optical system has a higher magnification, flare light becomes more conspicuous. Therefore, it is desirable to satisfy the condition (7) in a high magnification photographing optical system.

The light intensity of the flare light is the light generated from an arbitrary air contact surface between the objective lens and the final image position, and the light from the objective lens is the first air contact surface R.
1 is reflected to the objective lens side and further reflected to the final image side by the second air contact surface R2, and reaches the final image position. In addition to the lens surface, the air contact surface includes the surface of the image sensor.

In order to suppress the light intensity of the flare light, it is preferable to arrange a stop on the lens surface or the intermediate image formation position in the photographing optical system so that excess flare light does not reach the final image position. It is also important that the lens holding frame has a minimum effective diameter.

As described above, flare light depends on the number of lenses. Therefore, even if the light intensity of one flare light is small, if a plurality of flare lights are generated, the integrated value becomes large. In this case, as a matter of course, the contrast of the original image is deteriorated. For this reason, as the photographing optical system that satisfies the condition (7), it is preferable that each of the lens groups described above is an optical system including only one lens component or two lens components.

In the third configuration of the photographing optical system of the present invention, the radius of curvature of the air contact surface on the intermediate image side in the second lens group is R2G, and the distance from the air contact surface on the intermediate image side to the intermediate image is D2G. When doing so, it is desirable to satisfy the following conditions.

(8-1) 0.25 ≦ | R2G | /D2G≦0.9
(8-2) 1.5 ≦ | R2G | / D2G ≦ 15
By satisfying the condition (8-1) or the condition (8-2), the intensity of flare light reflected by the air contact surface on the intermediate image side and the other air contact surfaces in the second lens group is suppressed, and It is possible to prevent the flare light from becoming spot flare light. Therefore, it is possible to observe an image with good contrast. Even when the image sensor is arranged at the final image position, the intensity of flare light generated by reflection on the surface of the image sensor can be suppressed.

The range from the upper limit value 0.9 of the condition (8-1) to the lower limit value 1.5 of the condition (8-2) is the reflection on the air contact surface on the intermediate image side and the imaging element surface in the second lens group. The flare light caused by is a spot flare, which is not preferable. That is, if the upper limit of the condition (8-1) is exceeded and the lower limit of the condition (8-2) is exceeded, spot flare occurs, which is not preferable.

When the lower limit of the condition (8-1) is exceeded, the value of the curvature radius R2 becomes small. In order to maintain a predetermined magnification, the radius of curvature of the surface of the second lens group on the first lens group side must be increased. In this case, flare light is strongly generated by reflection between the surface of the second lens group on the first lens group side and the lens surface of the third lens group. As a result, the contrast deteriorates.

When the upper limit of the condition (8-2) is exceeded, the value of the radius of curvature R2G becomes large and the second
The radius of curvature of the object side surface of the lens group becomes small. As a result, spherical aberration and coma are deteriorated, which is not preferable.

In the third configuration of the photographing optical system of the present invention, the radius of curvature of the air contact surface with the convex surface facing the second lens group side of the third lens group is R3G, and the distance from the air contact surface to the intermediate image is D3G. It is desirable that the following condition (9) is satisfied.

(9) 0.7 ≦ R3G / D3G ≦ 1.2
If this condition (9) is satisfied, the intensity of flare light reflected from the air contact surface with the convex surface facing the second lens group side of the third lens group and other air contact surfaces is suppressed, and spot flare is prevented. Can do. Therefore, observation with good contrast becomes possible. Even when the image sensor is arranged at the final image position, the intensity of flare light generated by reflection on the surface of the image sensor can be suppressed.

Exceeding the upper limit of the condition (9) is not preferable because spot flare is strongly generated due to reflection between the convex surface of the third lens group and the imaging element surface.

When the lower limit of condition (9) is exceeded, the radius of curvature R3G of the convex surface becomes small. Therefore, spot flare light is generated by reflection between an air contact surface having a concave surface facing the intermediate image side in the second lens group and an air contact surface having a convex surface facing the intermediate image side in the third lens group.

Further, in the second configuration of the photographing optical system of the present invention, the radius of curvature of the air contact surface with the convex surface facing the third lens group side in the second lens group is R22, and from the intermediate image the second radius in the second lens group. When the distance to the air contact surface with the convex surface facing the three lens groups is D22,
It is desirable to satisfy the following condition (10).

(10) 0.8 ≦ | R22 | /D22≦1.6
This condition (10) is a condition for suppressing spot flare light caused by reflection between the air contact surface of the second lens group and the air contact surface of the third lens group. Also,
The condition (10) is also a condition for suppressing flare light generated between the surface of the image sensor and the air contact surface in the second lens group when the image sensor is arranged at the final image position.

If the upper limit of this condition (10) is exceeded, reflection between the air contact surface with the convex surface facing the third lens group in the second lens group and the imaging element surface, or the third in the second lens group.
Spot flare light due to reflection between the air contact surface with the convex surface facing the lens group side and the air contact surface in the third lens group becomes undesirably strong.

If the lower limit of the condition (10) is exceeded, the radius of curvature R22 of the air contact surface becomes small. In order to maintain the predetermined magnification, the radius of curvature of the air contact surface with the convex surface facing the intermediate image side in the second lens group becomes large. In this case, flare light due to reflection between the air contact surface with the convex surface facing the intermediate image side in the second lens group and the air contact surface in the third lens group becomes large, and the contrast deteriorates.

Next, a sixth configuration of the photographing optical system of the present invention is used for a microscope including an objective lens and an imaging lens, and includes a first lens group including a positive meniscus lens, a biconvex lens, and a biconcave lens. A second lens group including a negative cemented meniscus lens, and a third lens group including a cemented lens of a biconcave lens and a biconvex lens, and a positive lens, and is interposed between the second lens group and the third lens group. A stop is provided at the pupil conjugate position of the formed objective lens, and the following conditions (11), (12), (13), and (19) are satisfied.

(11) 0.7 ≦ D (I1) / D (3I) ≦ 1.3
(12) 0.35 ≦ D (13) / D (I) ≦ 0.65
(13) 0.2 ≦ | β | ≦ 0.5
(19) P _in = −P _out
Where D (I1) is the distance from the intermediate image to the tip of the first lens group, and D (3I)
Is the distance from the rear end of the third lens group to the final image, D (13) is the distance from the front end of the first lens group to the rear end of the third lens group, and D (I) is the distance from the intermediate image to the final image. Distance, β
The distance from the intermediate image to the magnification of the optical system to the final image, P _in the entrance pupil position of the intermediate image position (pupil position of the objective lens projected by the objective lens and the imaging lens), P
_out is a distance from the final image position to the exit pupil position (the pupil position of the objective lens projected by the objective lens, the imaging lens, and the photographing optical system).

The photographing optical system having the sixth configuration is used for a microscope, and is an optical system arranged after an intermediate image formed by an imaging lens of the microscope. The first lens group as a whole has a positive refractive power, the second lens group as a whole has a negative refractive power, and the third lens group as a whole has a positive refractive power. The light beam from the intermediate image is converged by the first lens group. The first lens group has a positive meniscus lens. Here, it is preferable that the positive meniscus lens has a shape with a convex surface facing the intermediate image side. The light beam converged by the first lens group is diverged by the second lens group. The second lens group has a negative cemented lens composed of a biconvex lens and a biconcave lens. The light beam diverged by the second lens group is converged by the third lens group to form a final image at a predetermined position. The third lens group includes a positive cemented lens including a biconcave lens and a biconvex lens, and a positive lens.

In the photographic optical system having the sixth configuration, when the lens groups are arranged in order of the first lens group, the second lens group, and the third lens group from the intermediate image side, the intermediate image is reduced at the final image position. Image is formed. Therefore, in the arrangement of the lens groups described above, the photographing optical system having the sixth configuration is an optical system with a reduction magnification.

The off-axis chief ray is highest in the first lens group. Further, the axial marginal ray becomes higher in the imaging lens and the third lens group. Since a conjugate image of the pupil of the objective lens is formed between the second lens group and the third lens group, a stop is disposed at the position of this conjugate image. This diaphragm has a function of limiting the numerical aperture of the objective lens.

In the sixth configuration, the aperture side surface of the second lens group and the aperture side surface of the third lens group are configured such that the concave surface is directed toward the aperture, respectively, so that off-axis aberrations are corrected well. ing. In addition, the negative refractive power of the second lens group suppresses the Petzval sum and improves the flatness of the image surface. The third lens group is configured to favorably correct spherical aberration by combining with the imaging lens. Further, the coma aberration generated in the second lens group is corrected by the first lens group and the third lens group. Further, a chromatic aberration is corrected by arranging a cemented lens in the second lens group and the third lens group.

In the sixth configuration, the conditions (11) to (13) and the condition (1)
9) is satisfied. Condition (19) defines the direction in which the entrance pupil and exit pupil are formed and the distance from the reference position. Both the entrance pupil and the exit pupil are conjugate images of the pupil of the objective lens, and the entrance pupil is a conjugate image formed by the objective lens and the imaging lens. The exit pupil is a conjugate image formed by an objective lens, an imaging lens, and a photographing optical system. The distance P _in to the entrance pupil position is a distance measured with reference to the intermediate image position, and the distance P _out to the exit pupil position is a distance measured with reference to the final image position.

If the condition (19) is satisfied, even if the entire photographing optical system is reversed, the positional relationship between the intermediate image and the final image and the positional relationship between the entrance pupil position and the exit pupil position are the same as before. Therefore, in the sixth configuration, if the first to third lens groups are arranged in the order of the first lens group, the second lens group, and the third lens group from the intermediate image position side, 0 is obtained.
. An imaging optical system can be configured in a magnification range of 2 to 0.5 times. If this optical system is inverted, the photographing optical system can be configured with a magnification range of 2 to 5 times. Here, inversion means that an appropriate point is set on the optical axis of the photographic optical system, and the photographic optical system is rotated 180 ° around this point. Therefore, in the imaging optical system after reversal, the lens groups are arranged in the order of the third lens group, the second lens group, and the first lens group from the intermediate image position side. Further, the positive cemented lens and the positive lens in the third lens group are arranged in the order of the positive lens and the cemented lens from the intermediate image side, and the biconcave lens is positioned on the intermediate image side in the negative cemented lens of the second lens group. The positive meniscus lens in the first lens group is in a state where the convex surface is directed to the final image position.

When the magnification is low from 0.2 to 0.5, the aperture diameter of the aperture stop is reduced to limit the numerical aperture of the objective lens. When the magnification is high, the aperture diameter is increased to increase the aperture of the objective lens. Do not limit.

When the projection optical system is a telecentric optical system, the entrance pupil position becomes infinity. In this case, the principal ray of the light beam reaching the final image position is parallel to the optical axis. Therefore, when imaging is performed with the image sensor disposed at the final image position, the chief ray enters the image sensor vertically. Therefore, it is preferable because shading does not occur. Thus, from the viewpoint of preventing the occurrence of shading, it is preferable that the photographing optical system is a telecentric optical system, but it is not always necessary to use a telecentric optical system. However, when it is not a telecentric optical system, it is desirable that the distance to the entrance pupil position is 200 mm or more in absolute value.

In the condition (19), the absolute value of the P _in value and the P _out value is equal, but it does not have to be exactly equal. There is no problem even if the value of P _in is slightly different from the value of P _out .

Further, this photographing optical system can secure the distance from the image pickup element to the photographing optical system when the photographing optical system is inverted by satisfying the condition (11).

Moreover, by satisfying the condition (12), the distance from the intermediate image to the image sensor can be shortened, and aberrations can be corrected well.

Furthermore, by satisfying the condition (13), it is possible to increase the magnification ratio when the photographing optical system is reversed with a lens group having a simple configuration. Therefore, observation at different magnifications is possible without converting the magnification of the objective lens, and the system performance and usefulness are increased.

If the upper limit of the condition (11) is exceeded, D (I1) becomes large. As a result, the total length of the photographing optical system becomes too long, which is not preferable. In addition, it becomes difficult to correct off-axis aberrations. If the lower limit of the condition (11) is exceeded, D (I1) becomes small. In this case, when the photographing optical system is reversed, the distance between the final image position and the first lens group is shortened. For this reason, when an image sensor is arranged at the final image position, the first lens group interferes with the image sensor. Alternatively, an imaging optical system that satisfies a predetermined specification cannot be configured.

When the lower limit of the condition (12) is exceeded, the distance from the intermediate image to the image sensor increases. For this reason, the photographing optical system cannot be made compact. In addition, off-axis coma, astigmatism, and lateral chromatic aberration on the low magnification side deteriorate.

When the upper limit of the condition (12) is exceeded, D (I1) and D (3I) become small. For this reason, if an image sensor is to be arranged at the final image position, interference between the lens group closest to the image sensor and the image sensor occurs, which is not preferable.

If the upper limit or lower limit of the condition (13) is exceeded, the ratio of the magnification on the low magnification side to the high magnification side becomes small when the photographic optical system is reversed, which is not preferable.

In the sixth configuration, the first lens group is a positive meniscus lens only, the second lens group is a negative cemented lens consisting of a biconvex lens and a biconcave lens, and the third lens group is a positive lens consisting of a biconcave lens and a biconvex lens. If the lens is composed only of a cemented lens and a positive lens, the photographing optical system can be made compact. Therefore, it is preferable in that the space for inversion can be reduced. Moreover, since the air contact surface can be reduced, generation of flare light can be suppressed.

In addition, if the optical system having the sixth configuration is used as the imaging optical system disposed after the imaging lens in the lens barrel of the present invention, it is desirable for the reasons described above.

The seventh configuration of the photographing optical system of the present invention is used for a microscope having an objective lens and an imaging lens, and includes a positive lens, a first lens group including a cemented lens of a biconvex lens and a biconcave lens, A first lens group having a second lens group including a negative cemented meniscus lens in which a concave lens and a biconvex lens are cemented, and a third lens group including a positive meniscus lens having a concave surface facing the second lens group; And the second lens group are provided with a stop at the pupil conjugate position of the objective lens, and the following conditions (14), (15), (1
6) and (19 ′) are satisfied.

(14) 0.7 ≦ D ′ (I1) / D ′ (3I) ≦ 1.3
(15) 0.35 ≦ D ′ (13) / D ′ (I) ≦ 0.65
(16) 0.2 ≦ | β ′ | ≦ 0.5
(19 ') P _in ' = -P _out '
Where D ′ (I1) is the distance from the intermediate image to the tip of the first lens group, and D ′ (3
I) is the distance from the rear end of the third lens group to the final image, D ′ (13) is the distance from the front end of the first lens group to the rear end of the third lens group, and D ′ (I) is from the intermediate image. The distance to the final image, β is the magnification of the optical system from the intermediate image to the final image, and P _in ′ is from the intermediate image position to the entrance pupil position (the pupil position of the objective lens projected by the objective lens and the imaging lens) The distance, P _out ′, is the distance from the final image position to the exit pupil position (the pupil position of the objective lens projected by the objective lens, the imaging lens, and the photographing optical system).

The photographing optical system having the seventh configuration is also used for a microscope, and is an optical system arranged after the intermediate image formed by the imaging lens of the microscope, as in the sixth configuration. The first lens group as a whole has a positive refractive power, the second lens group as a whole has a negative refractive power, and the third lens group as a whole has a positive refractive power. The light beam from the intermediate image is converged by the first lens group. The first lens group has a positive lens and a cemented lens. Here, the cemented lens includes a biconvex lens and a biconcave lens. The light beam converged by the first lens group is diverged by the second lens group. The second lens group has a negative cemented meniscus lens composed of a biconcave lens and a biconvex lens. The cemented meniscus lens is disposed with the concave surface facing the first lens group. The light beam diverged by the second lens group is converged by the third lens group to form a final image at a predetermined position. The third lens group has a positive meniscus lens having a concave surface facing the second lens group.

In the photographic optical system having the seventh configuration, when the lens groups are arranged in the order of the first lens group, the second lens group, and the third lens group from the intermediate image side, the intermediate image is enlarged at the final image position. Image is formed. Therefore, in the arrangement of the lens groups described above, the photographing optical system having the seventh configuration is an optical system having a magnification.

The off-axis chief ray is highest in the third lens group. In addition, the axial marginal ray becomes higher in the imaging lens and the first lens group. A conjugate image of the pupil of the objective lens is formed between the first lens group and the second lens group.

In the seventh configuration, off-axis aberrations are favorably corrected by configuring the final surface of the first lens unit and the foremost surface of the second lens unit to be concave surfaces. In addition, the negative refractive power of the second lens group suppresses the Petzval sum and improves the flatness of the image surface. The first lens group corrects spherical aberration satisfactorily by combination with an imaging lens. Further, the coma aberration generated in the second lens group is corrected by the first lens group and the third lens group. Chromatic aberration is corrected by arranging a cemented lens in the first lens group and the second lens group.

In the seventh configuration, the conditions (14) to (16) and the condition (1)
9 ′) is satisfied. Condition (19 ′) defines the direction in which the entrance pupil and exit pupil are formed, and the distance from the reference position. Both the entrance pupil and the exit pupil are conjugate images of the pupil of the objective lens, and the entrance pupil is a conjugate image formed by the objective lens and the imaging lens. The exit pupil is a conjugate image formed by an objective lens, an imaging lens, and a photographing optical system. Further, the distance P _in ′ to the entrance pupil position is a distance measured with reference to the intermediate image position, and the distance P _out ′ to the exit pupil position is a distance measured with reference to the final image position. .

If the condition (19 ′) is satisfied, even if the entire photographing optical system is reversed, the positional relationship between the intermediate image and the final image and the positional relationship between the entrance pupil position and the exit pupil position are not changed. Therefore, in the seventh configuration, if the first to third lens groups are arranged in the order of the first lens group, the second lens group, and the third lens group from the intermediate image position side,
A photographing optical system can be configured in a magnification range of 2 to 5 times. If this optical system is inverted, the photographing optical system can be configured with a magnification range of 0.2 to 0.5. Here, inversion means that an appropriate point is set on the optical axis of the photographic optical system, and the photographic optical system is rotated 180 ° around this point. Therefore, in the imaging optical system after reversal, the lens groups are arranged in the order of the third lens group, the second lens group, and the first lens group from the intermediate image position side. The positive meniscus lens of the third lens group is in a state where the convex surface is directed to the intermediate image position, and the biconvex lens of the negative cemented lens of the second lens group is positioned on the intermediate image side. The positive lens and the cemented lens in the first lens group are arranged in the order of the positive lens and the cemented lens from the final image side.

Also, when the magnification is high from 2 times to 5 times, the aperture diameter is increased so as not to limit the numerical aperture of the objective lens, and when the magnification is low from 0.2 times to 0.5 times, the aperture diameter of the aperture stop is set to be small. It is only necessary to reduce the numerical aperture of the objective lens to be small.

Similarly to the sixth configuration, when the photographing optical system of the seventh configuration is not a telecentric optical system, the distance to the entrance pupil position is increased, for example, 200 mm in absolute value.
It is desirable to make it above.

In the condition (19 ′), the absolute value of the value of P′in is equal to the value of P′out, but it does not have to be exactly the same. There is no problem even if the value of P′in is slightly different from the value of P′out.

In the seventh configuration, if the condition (14) is satisfied, it is desirable that the distance from the image sensor to the photographing optical system can be secured when the optical system is inverted.

Further, when the condition (15) is satisfied, the distance from the intermediate image to the image sensor can be shortened, and the aberration can be corrected favorably.

Furthermore, by satisfying the condition (16), the magnification ratio when the photographing optical system is reversed can be increased even with a simple configuration. Therefore, it is possible to observe a low magnification with a wide field of view and a high magnification with a high numerical aperture without converting the objective lens.

If the upper limit of the condition (14) is exceeded, D ′ (I1) becomes large. As a result, the entire length of the photographic optical system becomes too long, which is not preferable. In addition, it becomes difficult to correct off-axis aberrations. If the lower limit of the condition (14) is exceeded, D ′ (I1) becomes small. In this case, when the photographing optical system is reversed, the distance between the final image position and the first lens group is shortened. For this reason, when an image sensor is arranged at the final image position, the image sensor and the first lens group interfere with each other. Alternatively, it is difficult to configure a photographing optical system that satisfies a predetermined specification.

When the lower limit of the condition (15) is exceeded, the distance from the intermediate image to the image sensor increases.
For this reason, the photographing optical system cannot be made compact. In addition, off-axis coma, astigmatism, and lateral chromatic aberration on the low magnification side deteriorate.

When the upper limit of the condition (15) is exceeded, D ′ (I1) and D ′ (3I) become small.
Therefore, it is not preferable to place the image sensor at the final image position because the lens group closest to the image sensor interferes with the image sensor.

Exceeding the upper limit or lower limit of the condition (16) is not preferable because the ratio of the magnification on the low magnification side to the high magnification side becomes small when the photographing optical system is reversed.

In the seventh configuration, the first lens group is only a cemented lens made up of a positive lens, a biconvex lens and a biconcave lens, the second lens group is made only of a negative cemented lens made up of a biconcave lens and a biconvex lens, and the third lens group is made up. If it consists only of positive meniscus lenses,
The photographing optical system can be made compact. Therefore, it is preferable in that the space for inversion can be reduced. Moreover, since the air contact surface can be reduced, generation of flare light can be suppressed.

In the seventh configuration of the photographing optical system of the present invention, it is preferable that the following condition (17) is satisfied.

(17) 0.5 ≦ | R3 | /D3≦2.0
Where R3 is the radius of curvature of the surface of the third lens group facing the second lens group, and D3 is the third radius.
This is the distance from the surface on the second lens group side of the lens group to the final image position.

In the optical system having the seventh configuration according to the present invention, it is desirable to dispose a lens surface having a concave surface with respect to the light incident on the third lens group in order to correct aberrations well and improve optical performance. Therefore, the third lens group is composed of a positive meniscus lens. However, if the refractive power of the light beam on the lens surface is weak, strong flare light is caused by reflection between the lens surfaces of other lens groups. And spot flare light is likely to occur. Even when the image sensor is arranged at the final image position, flare light or spot flare light is likely to be generated by reflection on the surface of the image sensor.

If the condition (17) is satisfied, it is possible to suppress the intensity of flare light caused by reflection between the lens surface on the second lens group side of the third lens group and the lens surface on the second lens group side of the first lens group. Become. In addition, it is possible to suppress an increase in spot flare light generated between the surface of the imaging element and the surface on the second lens group side in the third lens group.

When the upper limit of the condition (17) is exceeded, the radius of curvature R3 increases, and spot flare light due to reflection between the imaging element and the lens surface on the second lens group side in the third lens group becomes strong. Therefore, observation with good contrast cannot be performed.

If the lower limit of condition (17) is exceeded, the curvature radius of the surface of the third lens group on the second lens group side becomes too small, and off-axis aberrations deteriorate.

Further, in this seventh configuration, the radius of curvature of the lens surface of the first lens group with the concave surface facing the second lens group is RA, and the distance from this surface to the pupil conjugate position is L1,
When the radius of curvature of the lens surface of the second lens group and the third lens group with the concave surface facing the first lens group is RB, and the distance from this surface to the pupil conjugate position is L2, the following condition (18) is satisfied. It is desirable to be satisfied.

(18) 0.5 ≦ (| RA | + | RB |) / (| L1 | + | L2 |)
≦ 1.5
In the seventh configuration, the cemented lens, the second lens group, and the third lens group in the first lens group direct concave surfaces with respect to the pupil conjugate position, thereby suppressing the occurrence of aberration on each lens surface and improving the aberration. However, since the refractive power of the lens surface facing the concave surface is weak, flare light and spot flare light are likely to be generated. Condition (18
If the flare light or spot flare light is generated by the lens surface with the concave surface facing the pupil conjugate position, the light intensity can be kept small.
Therefore, observation with good contrast becomes possible. Furthermore, all combinations of a lens surface having a concave surface facing the second lens group side of the first lens group and a lens surface having a concave surface facing the first lens group of the second lens group and the third lens group are in this condition (18 ) Is preferable because generation of flare light can be suppressed.

If the upper limit of condition (18) is exceeded, the absolute value of the radius of curvature of the lens surface with the concave surface facing the pupil conjugate position becomes large. For this reason, spot flare light due to reflection between this surface and the image sensor surface and flare light due to reflection between lens surfaces with concave surfaces facing each other are generated, resulting in poor contrast. If the lower limit of condition (18) is exceeded, the absolute value of the radius of curvature of the lens surface with the concave surface facing the pupil conjugate position will be small, and off-axis coma and astigmatism will deteriorate.

Even if the surface having RB that satisfies the condition (18) is in the second lens group,
It may be in the third lens group. Further, the surface having RB satisfying the condition (18) is
All surfaces of the second lens group and the third lens group are preferable.

Since the photographing optical system or the lens barrel of the present invention converts a magnification by exchanging another moving group with a part of the photographing optical system as a common fixed group without replacing the microscope objective lens, Observation of a wide field of view at a magnification and observation with a high numerical aperture are possible. In addition, vibrations and shocks that occur when changing the magnification can be suppressed. Therefore, it is possible to provide a microscope having excellent operability when performing the patch crank method or the like.
The flare light can be suppressed, and an image with good contrast can be observed even when the contrast of the image is enhanced.

    Next, embodiments of the photographing optical system and the lens barrel of the present invention will be described.

Of these embodiments, the embodiment relating to the photographic optical system and the lens system data of the photographic optical system used for each lens barrel are as follows. The photographic optical system is also described in detail including this data. explain.

Example 1
Table 1
(A) F / FO = 0.25
Surface number Curvature radius Spacing Nd Vd

1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.21
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (virtual surface) INF 25 1
7 55.766 9 1.48749 70.23
8 -68.077 6.087 1.62588 35.7
9 -700 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 38.9603 1
12 (MI) INF 62.1789 1
13 (S) INF 4.8551 1
14 -33.548 2.508 1.7725 49.6
15 28.624 8.5 1.64769 33.79
16 -60.262 19.8775 1
17 35.115 5.5 1.72151 29.23
18 16.968 8 1.497 81.54
19 -59.47 9.1931 1
20 86.508 2.592 1.48749 70.23
21 -49.944 14.2452 1
22 (virtual surface) INF 48.503 1
23 (IMG) INF
(B) F / FO = 0.35
Surface number Curvature radius Spacing Nd Vd

1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.21
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (virtual surface) INF 25 1
7 55.766 9 1.48749 70.23
8 -68.077 6.087 1.62588 35.7
9 -700 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 38.9603 1
12 (MI) INF 62.181 1
13 (S) INF 1 1
14 -33.548 2.508 1.7725 49.6
15 28.624 8.5 1.64769 33.79
16 -60.262 10.7707 1
17 35.115 5.5 1.72151 29.23
18 16.968 8 1.497 81.54
19 -59.47 9.1931 1
20 86.508 2.592 1.48749 70.23
21 -49.944 27.2049 1
22 (virtual surface) INF 48.503 1
23 (IMG) INF

(C) F / FO = 0.5
Surface number Curvature radius Spacing Nd Vd

1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.21
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (virtual surface) INF 25 1
7 55.766 9 1.48749 70.23
8 -68.077 6.087 1.62588 35.7
9 -700 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 38.9603 1
12 (MI) INF 51.5175 1
13 -33.548 2.508 1.7725 49.6
14 28.624 8.5 1.64769 33.79
15 -60.262 7.6641 1
16 (S) INF 0.3 1
17 35.115 5.5 1.72151 29.23
18 16.968 8 1.497 81.54
19 -59.47 9.1931 1
20 86.508 2.592 1.48749 70.23
21 -49.944 41.6751 1
22 (virtual surface) INF 48.503 1
23 (IMG) INF

(D) F / FO = 1
Surface number Curvature radius Spacing Nd Vd

1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.21
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (virtual surface) INF 25 1
7 55.766 9 1.48749 70.23
8 -68.077 6.087 1.62588 35.7
9 -700 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 38.9603 1
12 (MI) INF 15.6749 1
13 -33.548 2.508 1.7725 49.6
14 28.624 8.5 1.64769 33.79
15 -60.262 20.0021 1
16 35.115 5.5 1.72151 29.23
17 16.968 8 1.497 81.54
18 -59.47 9.1931 1
19 86.508 2.592 1.48749 70.23
20 -49.944 65.4796 1
21 (virtual surface) INF 48.503 1
22 (IMG) INF

Example 2
Table 2
Surface number Curvature radius Spacing Nd Vd

1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.21
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (virtual surface) INF 25 1
7 55.766 9 1.48749 70.23
8 -68.077 6.087 1.62588 35.7
9 -700 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 38.9603 1
12 (MI) INF 6.0809 1
13 26.067 1.385 1.7495 35.28
14 9.738 2.687 1.53996 59.46
15 -14.214 26.851 1
16 35.115 5.5 1.72151 29.23
17 16.968 8 1.497 81.54
18 -59.47 9.1931 1
19 86.508 2.592 1.48749 70.23
20 -49.944 75.1607 1
21 (virtual surface) INF 48.503 1
22 (IMG) INF

Example 3
Table 3
Surface number Curvature radius Spacing Nd Vd
1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.21
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (virtual surface) INF 25 1
7 55.766 9 1.48749 70.23
8 -68.077 6.087 1.62588 35.7
9 -700 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 3.7266 1
12 -47.778 5.5 1.72151 29.23
13 -35.313 5.5 1.51742 52.43
14 86.277 39.7091 1
15 14.214 2.687 1.53996 59.46
16 -9.738 1.385 1.7495 35.28
17 -26.067 10.142 1
18 (MI) INF 16.3771 1
19 14.488 2.1037 1.48749 70.23
20 -14.488 89.2796 1
21 INF 48.503 1
22 (IMG) INF

Table 4
Surface number Curvature radius Spacing Nd Vd

1 (immersion) INF 2.0435 1.33304 55.79
2 INF 1.61 1.45853 67.94
3 -2.406 5.76 1.755 52.32
4 -6.506 0.2 1
5 -25.5 3.15 1.497 81.08
6 -10.932 0.12 1
7 56.11 6.48 1.497 81.08
8 -11.989 1.95 1.52944 51.72
9 -25.367 0.12 1
10 223.746 1.95 1.755 52.32
11 17.04 6.5 1.43875 94.99
12 -25.491 0.12 1
13 12.142 4.826 1.43875 94.99
14 30.134 0.2 1
15 10.823 4.77 1.43875 94.99
16 26.536 1.502 1.59551 39.21
17 6.271 6.1162 1
18 -6.989 1.5 1.6134 43.84
19 18.167 6.37 1.43875 94.99
20 -11.567 0.25 1
21 -26.305 3.365 1.497 81.08
22 -11.876 0.12 1
23 10.941 7.05 1.43875 94.99
24 -25.628 1.65 1.52944 51.72
25 8.873 5.65 1
26 -8.409 1.75 1.51633 64.14
27 95.82 5.15 1.61293 36.99
28 -12.398 -5.2789 1
29 (virtual surface) INF 134 1
30 146.749 4 1.48749 70.21
31 -64.426 4.6 1.7495 35.28
32 -118.803 22.9 1
33 (M1) INF 25 1
34 55.766 9 1.48749 70.23
35 -68.077 6.087 1.62588 35.7
36 -700 15 1
37 (AN) INF 2 1.51633 64.14
VG (1)
38 INF 38.9603 1
39 (MI) INF 62.181 1
40 (S) INF 1 1
41 -33.548 2.508 1.7725 49.6
42 28.624 8.5 1.64769 33.79
43 -60.262 10.7707 1
44 35.115 5.5 1.72151 29.23
45 16.968 8 1.497 81.54
46 -59.47 9.1931 1
47 86.508 2.592 1.48749 70.23
48 -49.944 27.2049 1
49 (M2) INF 48.503 1
50 (IMG) INF 0

VG (3)
Radius of curvature interval Nd Vd

38 INF 3.7266 1
39 -47.778 5.5 1.72151 29.23
40 -35.313 5.5 1.51742 52.43
41 86.277 39.7091 1
42 14.214 2.687 1.53996 59.46
43 -9.738 1.385 1.7495 35.28
44 -26.067 10.142 1
45 (MI) INF 16.3771 1
46 14.488 2.1037 1.48749 70.23
47 -14.488 89.2796 1
48 (M2) INF 48.503 1
49 (IMG) INF

VG (2)
Radius of curvature spacing

38 INF 38.9603 1
39 (MI) INF 6.0809 1
40 26.067 1.385 1.7495 35.28
41 9.738 2.687 1.53996 59.46
42 -14.214 26.851 1
43 35.115 5.5 1.72151 29.23
44 16.968 8 1.497 81.54
45 (M1) -59.47 9.1931 1
46 86.508 2.592 1.48749 70.23
47 -49.944 75.1607 1
48 (M2) INF 48.503 1
49 (IMG) INF

Table 5
Surface number Curvature radius Spacing Nd Vd
1 (Immersion) INF 2.0435 1.33304 55.79
2 INF 1.61 1.45853 67.94
3 -2.406 5.76 1.755 52.32
4 -6.506 0.2 1
5 -25.5 3.15 1.497 81.08
6 -10.932 0.12 1
7 56.11 6.48 1.497 81.08
8 -11.989 1.95 1.52944 51.72
9 -25.367 0.12 1
10 223.746 1.95 1.755 52.32
11 17.04 6.5 1.43875 94.99
12 -25.491 0.12 1
13 12.142 4.826 1.43875 94.99
14 30.134 0.2 1
15 10.823 4.77 1.43875 94.99
16 26.536 1.502 1.59551 39.21
17 6.271 6.1162 1
18 -6.989 1.5 1.6134 43.84
19 18.167 6.37 1.43875 94.99
20 -11.567 0.25 1
21 -26.305 3.365 1.497 81.08
22 -11.876 0.12 1
23 10.941 7.05 1.43875 94.99
24 -25.628 1.65 1.52944 51.72
25 8.873 5.65 1
26 -8.409 1.75 1.51633 64.14
27 95.82 5.15 1.61293 36.99
28 -12.398 -5.2789 1
29 (virtual surface) INF 134 1
30 146.749 4 1.48749 70.21
31 -64.426 4.6 1.7495 35.28
32 -118.803 22.9 1
33 (M1) INF 25 1
34 39.702 7.786 1.48749 70.23
35 -60.804 3.5 1.7552 27.51
36 -268.304 15 1
37 (AN) INF 2 1.51633 64.14
VG (1)
38 INF 30.6035 1
39 (MI) INF 37.0115 1
40 (S) INF 1.7137 1
41 -12.087 1.5 1.7725 49.6
42 20.968 1.825 1.58144 40.75
43 -18.813 3.2546 1
44 -48.39 1.5 1.72825 28.46
45 16.539 6.03 1.497 81.54
46 -17.874 4.735 1
47 63.445 4.568 1.72916 54.68
48 -27.771 23.4696 1
49 (M2) INF 48.503 1
50 (IMG) INF
VG (3)

Surface number Curvature radius Spacing Nd Vd

38 INF 3 1
39 -32.071 8.6353 1.7552 27.51
40 -14.26 1.8412 1.51742 52.43
41 42.426 35.3807 1
42 13 2.3466 1.53996 59.46
43 -8.369 1.35 1.7495 35.28
44 -33.972 8.0849 1
45 (MI) INF 9.2033 1
46 8.973 7.2845 1.48749 70.23
47 -8.973 39.0845 1
48 (M2) INF 48.503 1
49 (IMG) INF 0 1

VG (2)
Surface number Curvature radius Spacing Nd Vd
38 INF 30.6035 1
39 (MI) INF 6 1
40 33.972 1.35 1.7495 35.28
41 8.369 2.3466 1.53996 59.46
42 -13 5.9856 1
43 -48.39 1.5 1.72825 28.46
44 16.539 6.03 1.497 81.54
45 -17.874 4.735 1
46 63.445 4.568 1.72916 54.68
47 -27.771 53.0923 1
48 (M2) INF 48.503 1
49 (IMG) INF

Table 5-1
(A) F / FO = 0.25
Surface number Curvature radius Spacing Nd Vd

1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.23
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (M1) INF 25 1
7 39.702 7.786 1.48749 70.23
8 -60.804 3.5 1.7552 27.51
9 -268.304 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 30.6035 1
12 (MI) INF 37.0115 1
13 (S) INF 9.4538 1
14 -12.087 1.5 1.7725 49.6
15 20.968 1.825 1.58144 40.75
16 -18.813 4.8684 1
17 -48.39 1.5 1.72825 28.46
18 16.539 6.03 1.497 81.54
19 -17.874 4.735 1
20 63.445 4.568 1.72916 54.68
21 -27.771 14.1158 1
22 (M2) INF 48.503 1
23 (IMG) INF

(B) F / FO = 0.35
Surface number Curvature radius Spacing Nd Vd

1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.23
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (M1) INF 25 1
7 39.702 7.786 1.48749 70.23
8 -60.804 3.5 1.7552 27.51
9 -268.304 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 30.6035 1
12 (MI) INF 37.0115 1
13 (S) INF 1.7137 1
14 -12.087 1.5 1.7725 49.6
15 20.968 1.825 1.58144 40.75
16 -18.813 3.2546 1
17 -48.39 1.5 1.72825 28.46
18 16.539 6.03 1.497 81.54
19 -17.874 4.735 1
20 63.445 4.568 1.72916 54.68
21 -27.771 23.4696 1
22 (M2) INF 48.503 1
23 (IMG) INF

(C) F / FO = 0.5
Surface number Curvature radius Spacing Nd Vd
1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.23
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (M1) INF 25 1
7 39.702 7.786 1.48749 70.23
8 -60.804 3.5 1.7552 27.51
9 -268.304 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 30.6035 1
12 (MI) INF 28.9125 1
13 -12.087 1.5 1.7725 49.6
14 20.968 1.825 1.58144 40.75
15 -18.813 3.2913 1
16 -48.39 1.5 1.72825 28.46
17 16.539 6.03 1.497 81.54
18 -17.874 4.735 1
19 63.445 4.568 1.72916 54.68
20 -27.771 33.2456 1
21 (M2) INF 48.503 1
22 (IMG) INF

(D) F / FO = 1
Surface number Curvature radius Spacing Nd Vd

1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.23
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (M1) INF 25 1
7 39.702 7.786 1.48749 70.23
8 -60.804 3.5 1.7552 27.51
9 -268.304 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 30.6035 1
12 (MI) INF 8.8628 1
13 -12.087 1.5 1.7725 49.6
14 20.968 1.825 1.58144 40.75
15 -18.813 9.0174 1
16 -48.39 1.5 1.72825 28.46
17 16.539 6.03 1.497 81.54
18 -17.874 4.735 1
19 63.445 4.568 1.72916 54.68
20 -27.771 47.5693 1
21 (M2) INF 48.503 1
22 (IMG) INF

Table 6
Surface number Curvature radius Spacing Nd Vd
1 (immersion) INF 2.0435 1.33304 55.79
2 INF 1.61 1.45853 67.94
3 -2.406 5.76 1.755 52.32
4 -6.506 0.2 1
5 -25.5 3.15 1.497 81.08
6 -10.932 0.12 1
7 56.11 6.48 1.497 81.08
8 -11.989 1.95 1.52944 51.72
9 -25.367 0.12 1
10 223.746 1.95 1.755 52.32
11 17.04 6.5 1.43875 94.99
12 -25.491 0.12 1
13 12.142 4.826 1.43875 94.99
14 30.134 0.2 1
15 10.823 4.77 1.43875 94.99
16 26.536 1.502 1.59551 39.21
17 6.271 6.1162 1
18 -6.989 1.5 1.6134 43.84
19 18.167 6.37 1.43875 94.99
20 -11.567 0.25 1
21 -26.305 3.365 1.497 81.08
22 -11.876 0.12 1
23 10.941 7.05 1.43875 94.99
24 -25.628 1.65 1.52944 51.72
25 8.873 5.65 1
26 -8.409 1.75 1.51633 64.14
27 95.82 5.15 1.61293 36.99
28 -12.398 -5.2789 1
29 (virtual surface) INF 134 1
30 146.749 4 1.48749 70.21
31 -64.426 4.6 1.7495 35.28
32 -118.803 22.9 1
33 (M1) INF 25 1
34 55.766 9 1.48749 70.23
35 -68.077 6.087 1.62588 35.7
36 -700 15 1
37 (AN) INF 2 1.51633 64.14
VG (1)
38 INF 41.4283 1
39 (MI) INF 69.4722 1
40 (S) INF 1.1263 1
41 -31.55 6.35 1.7725 49.6
42 29.835 12.664 1.66998 39.27
43 -55.26 10.5458 1
44 43.005 8 1.68893 31.07
45 20.034 12 1.497 81.54
46 -52.573 23.6507 1
47 142.299 10 1.48749 70.23
48 -71.269 31.2128 1
49 (M2) INF 48.503 1
50 (IMG) INF
VG (3)

Surface number Curvature radius Spacing Nd Vd
38 INF 3.0638 1
39 -38.279 7.24 1.72151 29.23
40 -33.398 10.026 1.60562 43.7
41 -123.477 36.4215 1
42 13 5.202 1.53996 59.46
43 -19.681 1.41 1.7495 35.28
44 -93.99 26.2482 1
45 17.032 7.8889 1.48749 70.23
46 -17.032 128.9496 1
47 (N2) INF 48.503 1
48 (IMG) INF
VG (2)

Surface number Curvature radius Spacing Nd Vd

38 INF 41.4283 1
39 (MI) INF 6 1
40 93.99 1.41 1.7495 35.28
41 19.681 5.202 1.53996 59.46
42 -13 31.3928 1
43 43.005 8 1.68893 31.07
44 20.034 12 1.497 81.54
45 -52.573 23.6507 1
46 142.299 10 1.48749 70.23
47 -71.269 87.3663 1
48 (M2) INF 48.503 1
49 (IMG) INF

Table 6-1
(A) F / FO = 0.25
Surface number Curvature radius Spacing Nd Vd
1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.21
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (M1) INF 25 1
7 59.137 8.95 1.48749 70.23
8 -92.109 6.6 1.68893 31.07
9 -700 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 41.4283 1
12 (MI) INF 69.4722 1
13 (S) INF 1.2287 1
14 -31.55 6.35 1.7725 49.6
15 29.835 12.664 1.66998 39.27
16 -55.26 27.5649 1
17 43.005 8 1.68893 31.07
18 20.034 12 1.497 81.54
19 -52.573 23.6507 1
20 142.299 10 1.48749 70.23
21 -71.269 14.0913 1
22 (M2) INF 48.503 1
23 (IMG) INF

(B) F / FO = 0.35
Surface number Curvature radius Spacing Nd Vd
1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.21
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (M1) INF 25 1
7 59.137 8.95 1.48749 70.23
8 -92.109 6.6 1.68893 31.07
9 -700 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 41.4283 1
12 (MI) INF 69.4722 1
13 (S) INF 1.1263 1
14 -31.55 6.35 1.7725 49.6
15 29.835 12.664 1.66998 39.27
16 -55.26 10.5458 1
17 43.005 8 1.68893 31.07
18 20.034 12 1.497 81.54
19 -52.573 23.6507 1
20 142.299 10 1.48749 70.23
21 -71.269 31.2128 1
22 (M2) INF 48.503 1
23 (IMG) INF 0 1

(C) F / FO = 0.5
Surface number Curvature radius Spacing Nd Vd
1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.21
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (M1) INF 25 1
7 59.137 8.95 1.48749 70.23
8 -92.109 6.6 1.68893 31.07
9 -700 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 41.4283 1
12 (MI) INF 57.9229 1
13 -31.55 6.35 1.7725 49.6
14 29.835 12.664 1.66998 39.27
15 -55.26 5.197 1
16 (S) INF 0 1
17 43.005 8 1.68893 31.07
18 20.034 12 1.497 81.54
19 -52.573 23.6507 1
20 142.299 10 1.48749 70.23
21 -71.269 49.2371 1
22 (M2) INF 48.503 1
23 (IMG) INF

(D) F / FO = 1
Surface number Curvature radius Spacing Nd Vd
1 (PU) INF 48.23 1
2 (virtual surface) INF 134 1
3 146.749 4 1.48749 70.21
4 -64.426 4.6 1.7495 35.28
5 -118.803 22.9 1
6 (M1) INF 25 1
7 59.137 8.95 1.48749 70.23
8 -92.109 6.6 1.68893 31.07
9 -700 15 1
10 (AN) INF 2 1.51633 64.14
11 INF 41.4283 1
12 (MI) INF 14.9695 1
13 -31.55 6.35 1.7725 49.6
14 29.835 12.664 1.66998 39.27
15 -55.26 22.3075 1
16 43.005 8 1.68893 31.07
17 20.034 12 1.497 81.54
18 -52.573 23.6507 1
19 142.299 10 1.48749 70.23
20 -71.269 75.0801 1
21 (M2) INF 48.503 1
22 (IMG) INF

Table 7

Surface number Curvature radius Spacing Nd Vd

1 (Immersion) INF 2.0435 1.33304 55.79
2 INF 1.61 1.45853 67.94
3 -2.406 5.76 1.755 52.32
4 -6.506 0.2 1
5 -25.5 3.15 1.497 81.08
6 -10.932 0.12 1
7 56.11 6.48 1.497 81.08
8 -11.989 1.95 1.52944 51.72
9 -25.367 0.12 1
10 223.746 1.95 1.755 52.32
11 17.04 6.5 1.43875 94.99
12 -25.491 0.12 1
13 12.142 4.826 1.43875 94.99
14 30.134 0.2 1
15 10.823 4.77 1.43875 94.99
16 26.536 1.502 1.59551 39.21
17 6.271 6.1162 1
18 -6.989 1.5 1.6134 43.84
19 18.167 6.37 1.43875 94.99
20 -11.567 0.25 1
21 -26.305 3.365 1.497 81.08
22 -11.876 0.12 1
23 10.941 7.05 1.43875 94.99
24 -25.628 1.65 1.52944 51.72
25 8.873 5.65 1
26 -8.409 1.75 1.51633 64.14
27 95.82 5.15 1.61293 36.99
28 -12.398 -5.2789 1
29 (virtual surface) INF 134 1
30 (virtual surface) INF 27 1
31 (M1) INF 27 1
32 INF 5 1
33 (AN) INF 3 1.51633 64.14
34 INF 5 1
35 186.092 7.05 1.48749 70.21
36 -62.009 4 1.7185 33.52
37 -107.745 148.626 1
38 (M2) INF 30 1
39 (MI) INF 45 1
(A)
40 30.618 6.6 1.8061 40.92
41 61.981 19.5 1
42 16.635 7.5 1.7 48.08
43 -19.996 3.5 1.8044 39.59
44 10.292 19.862 1
45 (S) INF 12.252 1
46 -27.262 4.6 1.8061 40.92
47 19.207 6 1.48749 70.23
48 -14.1779 0.663 1
49 22.83 4.7 1.48749 70.23
50 -35.276 44.4725 1
51 (IMG) INF
(B)
Surface number Curvature radius Spacing Nd Vd
39 (MI) INF 44.4725 1
40 35.276 4.7 1.48749 70.23

41 -22.83 0.663 1
42 14.1779 6 1.48749 70.23
43 -19.207 4.6 1.8061 40.92
44 27.262 12.252 1
45 (S) INF 19.862 1
46 -10.292 3.5 1.8044 39.59
47 19.996 7.5 1.7 48.08
48 -16.635 19.5 1
49 -61.981 6.6 1.8061 40.92
50 -30.618 45 1
51 (IMG) INF 0 1

Table 7-1
(A) (B)

Focal length of imaging lens 180 180
β 0.35 2.86
NAI 0.0475 0.0161
FIM 4.9 5.5
Aperture diameter Φ 2.444 3.4

D (I) 174.65 174.65
D (I1) 45 44.4725
D (3I) 44.4725 45
D (13) 85.177 85.177
β 0.35 2.86

D (I1) / D (3I) 1.011861263 0.988277778
D (13) / D (I) 0.487701117 0.487701117


R3 -61.981
D3 51.6
| R3 | / D3 1.201182171

RG1 surface number RG2 surface number ｜ RA ｜ ｜ RB ｜ ｜ L1 ｜ ｜ L2 ｜ Conditions (18)
40 46 35.276 10.292 28.215 19.862 0.947812883
40 48 35.276 16.635 28.215 30.862 0.878700679
40 49 35.276 61.981 28.215 50.362 1.237728597
40 50 35.276 30.618 28.215 56.962 0.773612595
42 46 14.1779 10.292 22.852 19.862 0.572877745
42 48 14.1779 16.635 22.852 30.862 0.573647466
42 49 14.1779 61.981 22.852 50.362 1.040223181
42 50 14.1779 30.618 22.852 56.962 0.561253665
44 46 27.262 10.292 12.252 19.862 1.169396525
44 48 27.262 16.635 12.252 30.862 1.018161154
44 49 27.262 61.981 12.252 50.362 1.425288274
44 50 27.262 30.618 12.252 56.962 0.836247002

The column of condition (18) shows the value of (| RA | + | RB |) / (| L1 | + | L2 |).

Table 8
F '/ F0 = 2
(A) Combinations where flare light is expected to be generated
First reflecting surface Second reflecting surface sin θ {(F / FO) · sin θ} ²
19 0 0.001 4.00E-06
2 0.0043 7.40E-05
3 0.0022 1.94E-05
4 0.0043 7.40E-05
6 0.0043 7.40E-05
7 0.0009 3.24E-06
9 0.0025 2.50E-05
13 0.0074 2.19E-04
15 0.0063 1.59E-04
17 0.0032 4.10E-05


17 0 0.0005 1.00E-06
2 0.0021 1.76E-05
3 0.0008 2.56E-06
4 0.0021 1.76E-05
6 0.0015 9.00E-06
7 0.0005 1.00E-06
9 0.0014 7.84E-06
13 0.0068 1.85E-04
15 0.0012 5.76E-06


15 0 0.0012 5.76E-06
2 0.0054 1.17E-04
3 0.0042 7.06E-05
4 0.005 1.00E-04
6 0.0054 1.17E-04
7 0.0011 4.84E-06
9 0.0027 2.92E-05
12 0.0054 1.17E-04
13 0.004 6.40E-05


13 0 0.001 4.00E-06
2 0.004 6.40E-05
3 0.0017 1.16E-05
4 0.004 6.40E-05
6 0.004 6.40E-05
7 0.0009 3.24E-06
9 0.0025 2.50E-05

9 0 0.019 1.44E-03
2 0.0052 1.08E-04
3 0.0037 5.48E-05
4 0.016 1.02E-03
6 0.0036 5.18E-05
7 0.0128 6.55E-04

7 0 0.0207 1.71E-03
2 0.0101 4.08E-04
3 0.0096 3.69E-04
4 0.0345 4.76E-03
6 0.0076 2.31E-04

6 0 0.0015 9.00E-06
2 0.0093 3.46E-04
3 0.0043 7.40E-05
4 0.0064 1.64E-04

4 0 0.0114 5.20E-04
2 0.0097 3.76E-04
3 0.0057 1.30E-04


3 0 0.0026 2.70E-05
2 0.0055 1.21E-04

2 0 0.0021 1.76E-05

(B) Large combination of flare light
Surface reflection combination sin θ {(F / FO) · sinθ} ²
9-0 0.019 0.001444
9-4 0.016 0.001024
9-7 0.0128 0.00065536
7-0 0.0207 0.00171396
7-2 0.0101 0.00040804
7-4 0.0345 0.004761
4-0 0.0114 0.00051984

(C) Flare light intensity distribution
Center area

0 0.2 0.4 0.6 0.8 1
9-0 1 0.938 0.723 0.502 0.193 0
9-4 1 1.011 1.008 1.011 0.984 0.746
9-7 1 1 1.008 0.855 0.364 0
7-0 1 0.986 0.888 0.491 0.093 0
7-2 1 1.026 0.453 0 0 0
7-4 1 0.822 0.547 0.14 0 0
4-0 1 1.005 1.005 1.036 1.057 0.75

Table 9
F "/ F0 = 4
(A) Combinations where flare light is expected to be generated
First reflecting surface Second reflecting surface sin θ {(F / FO) · sin θ} ²

19 0 0.0001 1.60E-07
2 0.001 1.60E-05
3 0.0014 3.14E-05
5 0.0003 1.44E-06
7 0.0002 6.40E-07
8 0.0016 4.10E-05
10 0.0074 8.76E-04
13 0.0037 2.19E-04
15 0.0031 1.54E-04
17 0.0016 4.10E-05

17 0 0.0001 1.60E-07
2 0.0007 7.84E-06
3 0.0007 7.84E-06
5 0.0001 1.60E-07
7 0.0001 1.60E-07
8 0.0007 7.84E-06
10 0.0007 7.84E-06
13 0.0034 1.85E-04
15 0.0006 5.76E-06

15 0 0.0001 1.60E-07
2 0.0009 1.30E-05
3 0.0018 5.18E-05
5 0.0004 2.56E-06
7 0.0003 1.44E-06
8 0.0022 7.74E-05
10 0.0033 1.74E-04
13 0.002 6.40E-05

13 0 0.0001 1.60E-07
2 0.0011 1.94E-05
3 0.0013 2.70E-05
5 0.0002 6.40E-07
7 0.0002 6.40E-07
8 0.0014 3.14E-05
10 0.0023 8.46E-05

10 0 0.0001 1.60E-07
2 0.0008 1.02E-05
3 0.0013 2.70E-05
5 0.0002 6.40E-07
7 0.0002 6.40E-07
8 0.0015 3.60E-05

8 0 0.002 6.40E-05
2 0.0054 4.67E-04
3 0.0026 1.08E-04
5 0.0018 5.18E-05
7 0.002 6.40E-05

7 0 0.001 1.60E-05
2 0.0014 3.14E-05
3 0.001 1.60E-05
5 0.0022 7.74E-05

5 0 0.0004 2.56E-06
2 0.0009 1.30E-05
3 0.0007 7.84E-06

3 0 0.0002 6.40E-07
2 0.0016 4.10E-05

2 0 0.0003 1.44E-06
0.00E + 00
(B) Large combination of flare light

Surface reflection combination sin θ {(F / FO) · sinθ} ²
8-2 0.0054 0.00046656

(C) Flare light intensity distribution
Center area
0 0.2 0.4 0.6 0.8 1
8-2 1 0.943 0.942 0.927 0.912 0.811

Table 10
F '/ FO = 2
(A) Combinations where flare light is expected to be generated
First reflecting surface Second reflecting surface sin θ {(F / FO) · sin θ} ²
19 0 0.0006 1.44E-06
2 0.0018 1.30E-05
3 0.0046 8.46E-05
4 0.0026 2.70E-05
6 0.0034 4.62E-05
7 0.0013 6.76E-06
9 0.0029 3.36E-05
13 0.0075 2.25E-04
15 0.0064 1.64E-04
17 0.0032 4.10E-05

17 0 0.0003 3.60E-07
2 0.0013 6.76E-06
3 0.0023 2.12E-05
4 0.0015 9.00E-06
6 0.002 1.60E-05
7 0.0007 1.96E-06
9 0.0017 1.16E-05
13 0.0031 3.84E-05
15 0.0009 3.24E-06


15 0 0.0004 6.40E-07
2 0.0012 5.76E-06
3 0.0034 4.62E-05
4 0.0018 1.30E-05
6 0.0023 2.12E-05
7 0.0009 3.24E-06
9 0.0019 1.44E-05
12 0.0042 7.06E-05
13 0.0026 2.70E-05


13 0 0.0004 6.40E-07
2 0.0014 7.84E-06
3 0.0032 4.10E-05
4 0.0019 1.44E-05
6 0.0025 2.50E-05
7 0.0009 3.24E-06
9 0.0021 1.76E-05

9 0 0.0042 7.06E-05
2 0.0115 5.29E-04
3 0.007 1.96E-04
4 0.0277 3.07E-03
6 0.0181 1.31E-03
7 0.0134 7.18E-04

7 0 0.0164 1.08E-03
2 0.0093 3.46E-04
3 0.011 4.84E-04
4 0.0196 1.54E-03
6 0.0297 3.53E-03

6 0 0.0041 6.72E-05
2 0.0107 4.58E-04
3 0.0297 3.53E-03
4 0.0166 1.10E-03

4 0 0.0044 7.74E-05
2 0.0092 3.39E-04
3 0.0062 1.54E-04

3 0 0.0013 6.76E-06
2 0.0052 1.08E-04

2 0 0.0013 6.76E-06


(B) Large flare light combination Surface reflection combination sin θ {(F / FO) · sinθ} ²

9-2 0.0115 0.000529
9-4 0.0277 0.00306916
9-6 0.0181 0.00131044
9-7 0.0134 0.00071824
7-0 0.0164 0.00107584
7-3 0.011 0.000484
7-4 0.0196 0.00153664
7-6 0.0297 0.00352836
6-2 0.0107 0.00045796
6-3 0.0297 0.00352836
6-4 0.0166 0.00110224
7-0 0.0162 0.00104976

(C) Flare light intensity distribution
Center area
0 0.2 0.4 0.6 0.8 1
9-2 1 0.985 0.994 0.972 0.976 0.953
9-4 1 1.001 0.985 0.956 0.919 0.866
9-6 1 1.01 1.008 1.003 1 1.005
9-7 1 1 0.989 0.988 0.838 0.578
7-0 1 0.977 0.373 0 0 0
7-3 1 1.011 0.878 0.256 0 0
7-4 1 1.018 0.881 0.623 0.358 0.124
7-6 1 0.939 0.669 0.405 0.167 0.006
6-2 1 1.036 1 1.035 1.004 1.039
6-3 1 0.808 0.564 0.34 0.143 0.008
6-4 1 1 0.997 0.939 0.877 0.802
7-0 1 0.206 0 0 0 0

F "/ FO = 4
(D) Combinations where flare light is expected to be generated
First reflecting surface Second reflecting surface sin θ {(F / FO) · sin θ} ²
19 0 0.0001 4.00E-08
2 0.0006 1.44E-06
3 0.0007 1.96E-06
5 0.0004 6.40E-07
7 0.0003 3.60E-07
8 0.0013 6.76E-06
10 0.0042 7.06E-05
13 0.0038 5.78E-05
15 0.0032 4.10E-05
17 0.0016 1.02E-05

17 0 0 0.00E + 00
2 0.0004 6.40E-07
3 0.0004 6.40E-07
5 0.0002 1.60E-07
7 0.0001 4.00E-08
8 0.0005 1.00E-06
10 0.0005 1.00E-06
13 0.0016 1.02E-05
15 0.0005 1.00E-06

15 0 0 0.00E + 00
2 0.0004 6.40E-07
3 0.0004 6.40E-07
5 0.0003 3.60E-07
7 0.0002 1.60E-07
8 0.0011 4.84E-06
10 0.0057 1.30E-04
13 0.0013 6.76E-06

13 0 0 0.00E + 00
2 0.0004 6.40E-07
3 0.0005 1.00E-06
5 0.0003 3.60E-07
7 0.0002 1.60E-07
8 0.0008 2.56E-06
10 0.0014 7.84E-06

10 0 0 0.00E + 00
2 0.0004 6.40E-07
3 0.0004 6.40E-07
5 0.0003 3.60E-07
7 0.0002 1.60E-07
8 0.0011 4.84E-06

8 0 0.0008 2.56E-06
2 0.0029 3.36E-05
3 0.0027 2.92E-05
5 0.0106 4.49E-04
7 0.0081 2.62E-04


7 0 0.0017 1.16E-05
2 0.0029 3.36E-05
3 0.0027 2.92E-05
5 0.0036 5.18E-05

5 0 0.0004 6.40E-07
2 0.0015 9.00E-06
3 0.0014 7.84E-06

3 0 0.0002 1.60E-07
2 0.0124 6.15E-04

2 0 0.0003 3.60E-07

(E) Large combination of flare light

Surface reflection combination sin θ {(F / FO) · sinθ} ²

15-10 0.0057 0.00051984
8-7 0.0081 0.00104976
8-5 0.0106 0.00179776
3-2 0.0124 0.00246016

(F) Intensity distribution of flare light
Center area
0 0.2 0.4 0.6 0.8 1
15-10 1 1.02 1.019 0.976 0.995 0.971
8-7 1 0.979 0.842 0.56 0.207 0
8-5 1 1 0.999 0.914 0.732 0.533
3-2 1 1 1.008 0.92 0.823 0.704

Table 11
F "/ F0 = 4
(A) Combination where flare light is expected to be generated
First reflecting surface Second reflecting surface sin θ {(F / FO) · sin θ} ²

19 0 0.0001 1.60E-07
2 0.0017 4.62E-05
3 0.0022 7.74E-05
5 0.0006 5.76E-06
7 0.0002 6.40E-07
8 0.0069 7.62E-04
10 0.0051 4.16E-04
13 0.0036 2.07E-04
15 0.0031 1.54E-04
17 0.0016 4.10E-05

17 0 0.0001 1.60E-07
2 0.0009 1.30E-05
3 0.0009 1.30E-05
5 0.0002 6.40E-07
7 0.0001 1.60E-07
8 0.0025 1.00E-04
10 0.0006 5.76E-06
13 0.0039 2.43E-04
15 0.0006 5.76E-06

15 0 0.0002 6.40E-07
2 0.0014 3.14E-05
3 0.0023 8.46E-05
5 0.001 1.60E-05
7 0.0004 2.56E-06
8 0.0037 2.19E-04
10 0.003 1.44E-04
13 0.0021 7.06E-05

13 0 0.0001 1.60E-07
2 0.0019 5.78E-05
3 0.0019 5.78E-05
5 0.0005 4.00E-06
7 0.0002 6.40E-07
8 0.0061 5.95E-04
10 0.0018 5.18E-05

10 0 0.0001 1.60E-07
2 0.001 1.60E-05
3 0.0018 5.18E-05
5 0.0005 4.00E-06
7 0.0002 6.40E-07
8 0.0033 1.74E-04

8 0 0.0003 1.44E-06
2 0.003 1.44E-04
3 0.0044 3.10E-04
5 0.0012 2.30E-05
7 0.0005 4.00E-06

7 0 0.0011 1.94E-05
2 0.0013 2.70E-05
3 0.0012 2.30E-05
5 0.0032 1.64E-04

5 0 0.0007 7.84E-06
2 0.0015 3.60E-05
3 0.0014 3.14E-05

3 0 0.0002 6.40E-07
2 0.0028 1.25E-04


2 0 0.0003 1.44E-06

(B) Large combination of flare light
Surface reflection combination sin θ {(F / FO) · sinθ} ²

19-10 0.0051 0.00041616
13-8 0.0061 0.00059536
8-0 0.0003 0.00000144

(C) Flare light intensity distribution
Center area
0 0.2 0.4 0.6 0.8 1
19-10 1 0.983 1 0.983 0.982 0.965
13-8 1 0.988 0.976 0.976 0.976 0.975

F '/ F0 = 2
(D) Combination where flare light is expected to be generated
First reflecting surface Second reflecting surface sin θ {(F / FO) · sin θ} ²
19 0 0.0015 9.00E-06
2 0.0043 7.40E-05
3 0.0015 9.00E-06
4 0.0043 7.40E-05
6 0.0043 7.40E-05
7 0.0008 2.56E-06
9 0.0032 4.10E-05
13 0.0073 2.13E-04
15 0.0063 1.59E-04
17 0.0032 4.10E-05

17 0 0.0008 2.56E-06
2 0.0015 9.00E-06
3 0.0006 1.44E-06
4 0.0021 1.76E-05
6 0.0015 9.00E-06
7 0.0004 6.40E-07
9 0.0018 1.30E-05
13 0.0077 2.37E-04
15 0.0013 6.76E-06

15 0 0.0019 1.44E-05
2 0.0055 1.21E-04
3 0.0027 2.92E-05
4 0.0051 1.04E-04
6 0.0055 1.21E-04
7 0.001 4.00E-06
9 0.004 6.40E-05
13 0.0042 7.06E-05

13 0 0.0015 9.00E-06
2 0.0038 5.78E-05
3 0.0013 6.76E-06
4 0.0041 6.72E-05
6 0.0041 6.72E-05
7 0.0008 2.56E-06
9 0.0032 4.10E-05

9 0 0.0295 3.48E-03
2 0.0059 1.39E-04
3 0.0046 8.46E-05
4 0.0142 8.07E-04
6 0.0048 9.22E-05
7 0.0174 1.21E-03


7 0 0.023 2.12E-03
2 0.0057 1.30E-04
3 0.0054 1.17E-04
4 0.0107 4.58E-04
6 0.0045 8.10E-05

6 0 0.0023 2.12E-05
3 0.0028 3.14E-05
4 0.0066 1.74E-04

4 0 0.0062 1.54E-04
2 0.0075 2.25E-04
3 0.0036 5.18E-05

3 0 0.0046 8.46E-05
2 0.0061 1.49E-04

2 0 0.003 3.60E-05

(E) Large flare light combination Reflective surface combination sin θ {(F / FO) · sinθ} ²
9-0 0.0295 0.003481
9-4 0.0142 0.00080656
9-7 0.0174 0.00121104
7-0 0.023 0.002116
7-4 0.0107 0.00045796
6-2 0.0178 0.00126736

(F) Intensity distribution of flare light
Center area
0 0.2 0.4 0.6 0.8 1
9-0 1 0.999 0.998 0.604 0.074 0
9-4 1 0.977 0.993 0.97 0.984 0.964
9-7 1 1 1.002 0.575 0.058 0
7-0 1 0.994 0.881 0.669 0.247 0
7-4 1 1.03 1.048 0.74 0 0
6-2 1 1 0.996 0.991 0.986 0.97

Table 12
(A) Combination in which flare light is expected to be generated β = 0.35 β = 2.86
First reflective surface Second reflective surface sin θ First reflective surface Second reflective surface sin θ
15 0 0.0124 15 0 0.0009
1 0.0048 1 0.0001
2 0.0031 2 0.0011
3 0.0043 3 0.0005
5 0.0128 5 0.0012
7 0.0098 7 0.0018
9 0.0075 9 0.0004
10 0.0475 10 0.0002
11 0.0041 11 0.0005
13 0.0139 13 0.0017

First reflective surface Second reflective surface sin θ First reflective surface Second reflective surface sin θ
13 0 0.0069 13 0 0.0004
1 0.003 1 0
2 0.0022 2 0.0004
3 0.0027 3 0.0002
5 0.0073 5 0.0004
7 0.0049 7 0.0007
9 0.0036 9 0.0002
10 0.0311 10 0.0001
11 0.0018 11 0.0002

First reflective surface Second reflective surface sin θ First reflective surface Second reflective surface sin θ
11 0 0.0139 11 0 0.0036
1 0.0038 1 0.0002
2 0.0021 2 0.0034
3 0.0036 3 0.0005
5 0.0139 5 0.0008
7 0.0186 7 0.0039
9 0.0207 9 0.0093
10 0.0349 10 0.002

First reflective surface Second reflective surface sin θ First reflective surface Second reflective surface sin θ
10 0 0.0475 10 0 0.0031
1 0.0155 1 0.0001
2 0.0081 2 0.0031
3 0.0144 3 0.0004
5 0.0475 5 0.0006
7 0.0475 7 0.0026
9 0.0475 9 0.0017

First reflective surface Second reflective surface sin θ First reflective surface Second reflective surface sin θ
9 0 0.019 9 0 0.0029
1 0.0047 1 0.0001
2 0.0024 2 0.0028
3 0.0043 3 0.0004
5 0.019 5 0.0007
7 0.0413 7 0.0035

First reflective surface Second reflective surface sin θ First reflective surface Second reflective surface sin θ
7 0 0.0233 7 0 0.0078
1 0.0051 1 0.001
2 0.0025 2 0.009
3 0.0048 3 0.0039
5 0.0233 5 0.0099

First reflective surface Second reflective surface sin θ First reflective surface Second reflective surface sin θ
5 0 0.1187 5 0 0.0037
1 0.0147 1 0.001
2 0.0063 2 0.0044
3 0.014 3 0.0096

First reflective surface Second reflective surface sin θ First reflective surface Second reflective surface sin θ
3 0 0.0114 3 0 0.0037
1 0.0666 1 0.0017
2 0.0045 2 0.0044

First reflective surface Second reflective surface sin θ First reflective surface Second reflective surface sin θ
2 0 0.0075 2 0 0.0125
1 0.0068 1 0.0073

First reflective surface Second reflective surface sin θ First reflective surface Second reflective surface sin θ
1 0 0.0125 1 0 0.0034

(B) Large combination of flare light (β = 0.35)

Reflective surface combination sin θ (β ・ sin θ) ²
5-0 0.1187 0.001725987
3-1 0.0666 0.000543356
10-0 0.0475 0.000276391
10-1 0.0475 0.000276391
10-5 0.0475 0.000276391
10-7 0.0475 0.000276391
10-9 0.0475 0.000276391

(C) Flare light intensity distribution On-axis image height
0 0.6 1.6 2.8 3.9 5
5-0 1 0.956 0.55 0.136 0 0
3-1 1 0.997 0.972 0.923 0.115 0.046
10-0 1 0.904 0.205 0 0 0
10-1 1 1.001 0.701 0 0 0
10-5 1 0.905 0.267 0 0 0
10-7 1 0.968 0 0 0 0
10-9 1 0.765 0 0 0 0

(D) Large combination of flare light (β = 2.86)

Reflective surface combination sin θ (β ・ sin θ) ²
2−0 0.0125 0.001278063
7-5 0.0099 0.000801683
5−3 0.0096 0.000753832
11−9 0.0093 0.000707454

(E) Flare light intensity distribution On-axis image height
0 1.1 2.2 3.3 4.4 5.5
2-0 1 1.004 1.009 1.023 1.041 1.051
7-5 1 0.985 0.997 0.814 0.455 0.068
5-3 1 1.009 1.012 1.014 1.018 0.972
11-9 1 0.993 0.99 0.976 0.956 0.882

In the above data, the surface numbers are obtained by sequentially describing each surface from the object side, such as ₁ , ₂ ,..., ₁ , ₂ ,... Are r ₁ , r ₂ ,. Correspondingly, the radius of curvature is the value of the radius of curvature r ₁ , r ₂ ,... Of the surface, and the spacing is d ₁ , d _{2 in the} figure.
,..., Nd and Vd indicate the refractive index and Abbe number for the d line. NA
I is the numerical aperture at the final image position, FIM is the image height at the final image position, FL is the focal length from the imaging lens to the final surface of the photographing optical system, AN is a polarizing plate, M1 and M2 are reflection mirrors, and S is a diaphragm The position, IMG, indicates the final image position. The INF in the data is infinite. MI is the intermediate image position, and PU is the pupil of the objective lens.

Furthermore, after Table 8, data on flare light (data related to condition (7))
The first reflection surface and the second reflection surface indicate surface numbers, respectively, and flare light is reflected by reflection at the surface number indicated by the first reflection surface and by reflection at the surface number indicated by the second reflection surface. The value of the incident angle θ to the image sensor, the value of sin θ, and the value of {(F / (FO) · sin θ} ² are shown.

The imaging optical system according to the first embodiment of the present invention is an imaging optical system having a first configuration. As shown in FIG. 1 and Table 1 (Example 1), the imaging lens IML (r _{3 to} r ₅ ). It is arranged following. The imaging optical system includes a first lens group by joining a positive lens and a negative lens positive cemented lens LG1 (r ₇ ~r _9), a negative lens and a positive lens having a concave surface facing the first lens group LG1 side The second lens group LG2 (r _{14 to} r ₁₆ ) of a negative cemented meniscus lens, and a positive cemented lens composed of a negative meniscus lens and a biconvex lens, and a biconvex lens. Three lens group LG3 (r ₁₇
~r ₂₁₎ and made more. Then, an intermediate image MI is formed by the first lens group G1.

In the photographing optical system of the first embodiment (Example 1), the light beam from the objective lens is converged by the imaging lens IML, and the intermediate image MI (
r ₁₂ ) is formed. This intermediate image MI is formed as a final image IMG (r ₂₄ ) by the second lens group LG2 and the third lens group LG3. This photographing optical system includes an aperture stop S (r ₁₃ ) at a position conjugate with the pupil position of the objective lens. Therefore, the numerical aperture of the objective lens can be limited by changing the diameter of the stop. A polarizing plate AN (r _{10 to} r ₁₁ ) is disposed between the first lens group LG1 and the intermediate image MI. If this polarizing plate can cope with wavelengths in the infrared region, infrared differential interference observation can be performed with the photographing optical system. Further, a diaphragm (flare diaphragm) is disposed on the lens surface or the intermediate image position so that excess flare light does not enter the image sensor. That is, the effective diameter required for the holding frame that holds the lens is set. Note that PU (r ₁ ) is the pupil position of the objective lens.

In FIG. 1, (A) shows the magnification of the photographing optical system is 0.25 times, and (B) shows 0.35.
Magnification, (C) is 0.5 times, and (D) is a state of arrangement of each lens group when it is 1 time. In addition, the lens data of (A) to (D) in Table 1 of the data are shown in (A
) To (D). Here, as can be seen from (A) to (D) in Table 1 of the data, the photographing optical system of each magnification is composed of the same lens. As described above, the photographing optical system according to the first embodiment can realize photographing optical systems having different magnifications only by changing the arrangement positions of the lens groups.

Note that if the distance (d ₁₆ ) between the second lens group LG2 and the third lens group LG3 and the distance (d ₂₁ ) between the third lens group LG3 and the image pickup device are changed, 0.25 times to 1 The magnification can be changed stepwise or continuously up to twice.

That is, in the state where the magnification shown in Table 1 (A) is 0.25, d ₁₆ = 19.87
75, d ₂₁ = 14.2452 as shown in Table 1 (B), d ₁₆ = 10.7701,
When the change is made to d ₂₁ = 27.2049, the magnification becomes 0.35. Further, as shown in Table 1 (C), when d ₁₆ = 7.66641 and d ₂₁ = 41.6751 are changed, the magnification is 0.5.
become. Further, as shown in Table 1 (D), d ₁₆ = 20.0021, d ₂₁ = 65.4796
When changed to, the magnification changes to 1. Note that the position of the diaphragm differs when the magnification is 0.25 (or .35) and 0.5. Further, when the magnification is 1, no aperture is required. For this reason, when the photographing optical system is a zoom optical system, the diaphragm can be moved in a direction perpendicular to the optical axis, and it can be inserted and removed according to each magnification. Alternatively, the diaphragm may be movable in the optical axis direction, and the maximum diameter of the diaphragm may be made larger than that of the lens so that the lens group can pass through the diaphragm.

As described above, in the optical system according to the first embodiment, the magnification is within the range of the condition (1). Further, as shown in Table 1-1, the value of D1 / D satisfies the condition (2).

Further, the magnification is 0.25, 0.35, 0.5, 1 (the focal length F of the photographing optical system is 4).
5, 63, 90, 180 (mm)), the aperture stop diameters are 2.492, 3.4, respectively.
88, 7.2 (mm), open.

FIG. 14 (magnification 0.25) and FIG. 15 (magnification 0.
35), FIG. 16 (magnification 0.5), and FIG. 17 (magnification 1).

A second embodiment shown in FIG. 2 and Table 2 (Example 2) is a second configuration of the photographing optical system according to the present invention, and is arranged subsequent to the imaging lens IML (r _{3 to} r ₅ ). Is. The imaging optical system, the second positive lens and a positive first lens group LG1 (r ₇ ~r ₉₎ and a negative meniscus lens and a positive lens and a positive cemented lens of the cemented lens consisting of a negative lens lens group LG2 and (r ₁₃ ~r _15), the third lens group becomes more negative meniscus lens and a positive lens and a positive cemented lens and a biconvex lens formed by joining LG3
(R _{16 to} r ₂₀ ). Then, an intermediate image MI (r ₁₂
) Is formed.

In the second embodiment, similarly to the first embodiment, the light beam from the objective lens is converged by the imaging lens IML, and the intermediate image MI is formed by the first lens group LG1. Then, the intermediate image MI is formed as a final image IMG (r ₂₂ ) by the second lens group LG2 and the third lens group LG3. However, the second embodiment is different from the first embodiment in that the second lens group LG2 is a lens group having a positive refractive power with a convex surface facing the intermediate image MI.

The magnification (F / FO) of the second embodiment is 2 as shown in Table 2-1, which is within the range of the condition (3), and D2 / D is the condition (see Table 2-1). 4) is satisfied. Further, the condition (10) is satisfied.

In the second embodiment, similarly to the first embodiment, a polarizing plate AN (r _{10 to} r ₁₁ ) is disposed between the first lens group LG1 and the intermediate image MI. Differential interference observation. In order to suppress flare light, a stop may be disposed near the lens surface of the photographing optical system or in the intermediate image position. Further, the lens holding frame can be configured to have a minimum necessary effective diameter.

    The aberration situation of the second embodiment is as shown in FIG.

A third embodiment shown in FIG. 3 and Table 3 (Example 3) is a third configuration of the photographing optical system of the present invention, and is arranged subsequent to the imaging lens IML (r _{3 to} r ₅ ). Is. The imaging optical system includes a first lens group consisting of a positive cemented lens in which a positive lens and a negative lens LG1 (r ₇ ~r _9), formed of a negative cemented lens in which a positive lens and a negative lens A second lens group LG2 (r _{12 to} r ₁₄ ), a third lens group LG3 (r _{15 to} r ₁₇ ) composed of a positive cemented lens in which a positive lens and a negative lens are cemented, and a convex surface of the intermediate image MI (r ₁₈₎ is a positive lens (optical system constituted by the fourth lens group LG4 made of a biconvex lens) (r ₁₉ ~r ₂₀₎ toward the side. The third lens unit L
An intermediate image MI is formed between G3 and the fourth lens group LG4.

In the third embodiment, the light beam from the objective lens is converged by the imaging lens, and the intermediate image MI is formed by the lens groups up to the third lens group LG3. This intermediate image MI is formed as a final image IMG (r ₂₂ ) by the fourth lens group. Further, similarly to the first embodiment, the polarizing plate A is disposed between the first lens group LG1 and the intermediate image MI (in this embodiment, between the first lens group LG1 and the second lens group LG2).
N is arranged. In addition, the aperture is close to the lens surface of the photographing optical system and to the intermediate image position (
A flare stop) may be provided so that excess flare light does not enter the image sensor. Further, a minimum necessary effective diameter may be set for the lens holding frame.

The magnification (F ″ / FO) of the third embodiment is 4 as shown in Table 3-1,
Further, the condition (5) is satisfied.

    Moreover, as shown in Table 3-1, the conditions (8-2) and (9) are satisfied.

    The aberration status of the third example is as shown in FIG.

FIG. 4 and Table 4 show a fourth embodiment of the present invention, and are a fourth configuration and a fifth configuration of the photographing optical system of the present invention. In this figure, the objective lens and the imaging lens are also shown, and the lens data of the objective lens and the imaging lens are also described in the data shown in Table 4.

In this figure, OB (r _{2 to} r ₂₈ ) is an objective lens, IML (r _{30 to} r ₃₂ ) is an imaging lens, M1 (r ₃₃ ) is a 90 ° deflection of the light beam that has passed through the objective lens OB and the imaging lens IML. A deflecting member (mirror) M2 (r ₄₈ ) is a second deflecting member (mirror) that is further deflected by 90 °. The tip of the objective lens OB (r _{1 to} r ₂ )
Assumes that there is water as immersion liquid. The virtual surface r ₂₉ is a position where the objective lens is mounted.

In FIG. 4, the photographing unit disposed between the two deflecting members M1 and M2 is the photographing optical system of the third embodiment described above. The photographic optical system of the first embodiment is shown below (a part of) the photographic optical system of the third embodiment, and below that is the photographic optical system of the second embodiment. (Part) is shown.
Here, the photographing optical systems of the first to third embodiments are referred to as first to third photographing units, respectively.

In the first photographing unit, the first lens group LG1 is a fixed group, and the second lens group L
G2 and the third lens group LG3 are a moving group (hereinafter referred to as a first moving group VG1). In the second photographing unit, the first lens group LG1 is a fixed group, and the second lens group LG2 and the third lens group LG3 are moving groups (hereinafter referred to as a second moving group VG (2)). is there. In the third photographing unit, the first lens group LG1 is a fixed group,
The second lens group LG2, the third lens group LG3, and the fourth lens group LG4 are moving groups (hereinafter referred to as third moving group VG (3)). Note that the position at which the intermediate image (MI) is formed is the same as in the first to third embodiments.

Then, the third moving group VG (3) and the first moving group VG (1) of the fixed group FG and the moving group VG are exchanged to form the fifth configuration of the present invention. As a result, the magnification of the photographing optical system can be converted from a high magnification of 4 times to a low magnification of 0.35 times.

If the second movement group VG (2) and the first movement group VG (1) (unit C in the data) are exchanged, the fourth configuration of the present invention is obtained. In this case, the magnification of the photographing optical system can be converted from 2 times to 0.35 times.

That is, in the fourth embodiment, the photographing optical system is a fixed group FG of the first lens group.
And a moving group VG after the second lens group, and this moving group VG is the first moving group VG (1) and the second moving group VG (2), or the first moving group VG (1 ) And third
This is an example of an imaging optical system capable of converting the magnification by exchanging the moving group VG (3). Note that the distance from the imaging lens to the final image when the moving group VG is exchanged is always constant.

Since the distance L between the two deflecting members M1 and M2 is 233.5 mm,
The photographing optical system of the present embodiment satisfies the condition (6).

Further, in the photographing optical system including the first configuration, that is, the fixed group FG and the first moving group VG (1), as described above, the distance between the lens groups of the first moving group is changed. In addition, the magnification of the photographing optical system can be changed from 0.25 times to 1 time. In this case, the zoom optical system may be configured by continuously changing the distance between the second lens group and the third lens group.

Thus, according to the fourth embodiment, observation or photographing from low magnification to high magnification is possible without switching the objective lens.

As described above, since the objective lens is not switched when the magnification is converted, there is no impact or vibration caused by the switching of the objective lens. Further, since there is no need to operate the revolver or switch the objective lens, the space around the objective lens is widened. Therefore, an apparatus for performing an application such as the patch clamp method can be arranged. In addition, since the objective lens used in this embodiment has a magnification of 20 and a numerical aperture of 0.92, the total magnification when the moving group VG (1) having a low magnification is 7 is 7.
The numerical aperture is 0.13 due to the aperture stop S. On the other hand, high magnification moving group V
When G (3) is used, the overall magnification is 80 times and the numerical aperture is 0.92. Therefore, it is possible to search for the position of a wide range of specimens and to photograph cell structures and the like with one objective lens.

Incidentally, the data in Table 4, surface numbers of the mirror M2 of the first moving group VG (1) has become a r _49, the second movable group VG (2) and the third movable group VG (3) This is different from the surface number r ₄₉ of the mirror M2. This is due to the difference in the lens configuration of the moving group and the presence or absence of a stop. Therefore, the position of the mirror M2 is always fixed at the same position regardless of which moving group is exchanged.

The imaging optical system of the fourth embodiment is basically intended to perform observation at a low magnification and observation at a high magnification. Therefore, the first moving group VG (1
) And the second movement group VG (2), or the first movement group VG (1) and the third movement group VG (3) are exchanged. However, if necessary, the second moving group V
You may exchange G (2) and 3rd movement group VG (3). Further, instead of exchanging the two moving groups, the three moving groups can be exchanged sequentially.

The aberration status of the photographic optical system having the fourth configuration is shown in FIG. 20 (magnification 0.35) and FIG.
1 (magnification 4).

FIG. 5 shows a lens barrel according to a fifth embodiment of the present invention. 4 is a lens barrel including the photographing optical system shown in FIG. 4 and capable of changing the magnification of the photographing optical system by converting two moving groups. Therefore, the condition (7) is satisfied.

In FIG. 5, reference numeral 1 denotes an objective lens, 2 denotes a dichroic mirror which is a first optical path splitting element, and 3 denotes a lens barrel in which a photographing optical system 4 is provided which is arranged on an optical path reflected by the first optical path splitting element 2. Reference numeral 5 denotes a first image pickup apparatus including an image pickup element, 6 denotes an intermediate zoom unit provided in an optical path transmitted through the first optical path splitting element 2, 7 denotes an eyepiece optical system, 9
Is a second imaging device connected to the intermediate magnification unit 7, and 10 is a sample.

Further, 11 is a transmission illumination system as a first illumination system, 20 is an epi-illumination system as a second illumination system, 30 is an image processing device, and 40 is a display device.

In the lens barrel 3 of the present invention, the optical path dividing element 2 is a dichroic mirror and has a characteristic of transmitting visible light and reflecting infrared light (700 nm to 1200 nm). Therefore, for example, when infrared illumination is performed by the transmission illumination system 11, the infrared light from the specimen 10 is reflected by the optical path dividing element 2 and guided to the photographing optical system 4 disposed in the reflection side optical path. Then, the final image is formed on the image sensor in the first imaging device 5 by the photographing optical system 4. An image captured by the image sensor is subjected to image processing by the image processing device 30 and then displayed on the display device 40, whereby an infrared image can be observed.

Here, the photographing optical system 4 has a photographing unit A and a photographing unit B. Assuming that the photographing unit A is a low magnification optical system, 0.2 shown in the first embodiment.
Any one of the 5 × to 1 × optical systems is used in the photographing unit A.
On the other hand, the photographing unit B becomes a high magnification optical system. Therefore, the 2 × optical system shown in the second embodiment or the 4 × optical system shown in the third embodiment is used for the photographing unit B. As shown in the fourth embodiment, the photographing unit A and the photographing unit B are configured by a common fixed lens group FG and a moving lens group VG.

Thus, for example, the photographing unit A is 0.25 times optical system and the photographing unit B is 2
In the case of a double optical system, for example, 0.25x and 2x infrared images can be obtained by exchanging the moving lens group VG (1) and the moving lens group VG (2). Further, for example, if the photographing unit A is a 0.5 × optical system and the photographing unit B is a four times optical system, the moving lens group VG (1) and the moving lens group VG (3) are exchanged by replacing the moving lens group VG (1) with the moving lens group VG (3). 5 and 4 times infrared images can be obtained.

The AN provided in the lens barrel 3 is a polarizing element and is used when obtaining a differential interference image of infrared light. In order to obtain a differential interference image, it is necessary to dispose a polarizing element (polarizer) and a differential interference prism as in the conventional case. As a matter of course, these optical elements have optical characteristics corresponding to the infrared region.

On the other hand, if fluorescent epi-illumination is performed by the epi-illumination system 20, the fluorescence from the specimen 10 passes through the optical path dividing element 2 and is guided to the eyepiece optical system 7 disposed in the transmission side optical path. Therefore, fluorescence can be observed through the eyepiece optical system 7. In FIG.
Although a member for guiding the fluorescence that has passed through the optical path splitting element 2 to the eyepiece optical system 7 is not shown, a prism as used in a conventional observation barrel may be disposed.

In the present embodiment, the intermediate magnification unit 6 and the second imaging device 9 each having the second imaging optical system 8, 8 ′ are disposed in the transmission side optical path of the optical path dividing element 2. The second imaging optical system 8, 8 'is held so as to be movable, and either one is inserted into the optical path. Therefore, by exchanging the second photographing optical systems 8 and 8 ′, a fluorescent image enlarged or reduced at a predetermined magnification can be obtained. Then, if this fluorescent image is taken by the second imaging device 9, the fluorescent image can be observed.

In addition to the differential interference image in the fluorescence and infrared regions, simultaneous observation of fluorescence and differential interference in the visible region and a plurality of images with different magnifications may be performed. Further, instead of the dichroic mirror used as the optical path splitting element 2 or the like, a reflecting mirror or a beam splitter may be used.

Therefore, according to the lens barrel of the present embodiment, the differential interference image in the infrared region can be observed at different magnifications by the reflection side optical path. On the other hand, observation by the eyepiece optical system and observation by the second photographing optical system are possible by the transmission side optical path. Further, since it is not necessary to convert the objective lens 1 near the specimen 10 for magnification conversion, vibration and impact can be suppressed. Since the space near the specimen can be widened, it is excellent in operability when performing various applications such as the patch crank method.

FIG. 6 and Table 5 show a sixth embodiment of the present invention, which is another example of the fourth embodiment. As in the fourth embodiment, the fixed group FG and a plurality of sets of moving groups VG are used, and the magnification of the photographing optical system is converted by exchanging the moving groups.

Lens data of the photographing optical system according to the sixth embodiment is as shown in Table 5. The lens data in Table 5 includes the objective lens OB (r _{2 to} r ₂₈ ), the virtual surface (r ₂₉ ) indicating the position where the objective lens is mounted, and the imaging lens IML (r _{30 to} r ₃₂ ). ing. Further, it is assumed that there is water as immersion liquid at the tip of the objective lens OB.

Subsequent to the mirror M1 (r ₃₃ ), a first photographing unit having a magnification of 0.35 is disposed. The first photographing unit includes a first lens group LG1 (r _{34 to} r ₃₆ ), an aperture S (r ₄₀ ), a second lens group LG2 (r _{41 to} r ₄₃ ), and a third lens group LG3 (r _44).
~r ₄₈₎ consisting of. In this embodiment, in order to perform differential interference observation, polarizing plate A
N (r _{37 to} r ₃₈ ) is arranged in the optical path. The intermediate image MI (r ₃₉ ) is the first
It is formed between the lens group LG1 and the second lens group LG2. Then, a mirror M2 (r ₄₉ ) is arranged following the third lens group LG3, and a final image IMG (r ₅₀ ) is formed.

Here, among the lens groups of the first photographing unit, the first lens group LG1 is a fixed lens group FG, and the second lens group LG2 and the third lens group LG3 are moving lens groups VG.
(1). Table 5 also describes lens data of a third photographing unit with a magnification of 5 and a second photographing unit with a magnification of 2. However, the first to third
Since the first lens group LG1 of the imaging unit is a common fixed lens group FG, what is shown below the first imaging unit in FIG. 8 is the third imaging unit and the second imaging unit. These are the moving lens groups VG (3) and VG (2). Note that the position of the intermediate image (MI) is between the third lens group LG3 and the fourth lens group LG4 in the third imaging unit, and between the first lens group LG1 and the second lens group LG2 in the second imaging unit. Between.

In the sixth embodiment, the first moving group VG (1) and the third moving group VG (3) are exchanged to reduce the magnification of the photographing optical system (0.35).
Times) to high magnification (4 times). Further, the magnification can be changed from a low magnification to an intermediate magnification (2 times) by exchanging with the second moving group VG (2).

In the optical system of the sixth embodiment, the imaging magnification is changed from 0.25 to 1 by changing the distance between the second lens group LG2 and the third lens group LG3 in the first imaging unit. be able to. (A), (B) of FIG.
(C) and (D) show the arrangement of each lens group when the magnification is changed.
) Is 0.25 times, (B) is 0.35 times, (C) is 0.5 times, and (D) is 1 time. Data at each magnification is as shown in Table 5-1. Table 5-
Surfaces corresponding to surface numbers 1 and 2 in 1 are not shown in FIG.

Also, D1 / D at each magnification in a photographing unit of 0.25 to 1 times, 2
D2 / D in double shooting unit and R3G in 4x shooting unit
The value of / D3G is as shown in Table 5-2.

As shown in Table 5-2, the optical system of the sixth embodiment has the condition (2).
, Condition (4), Condition (8-2), Condition (9), and Condition (10) are satisfied. Also,
Since the distance L between the mirrors M1 and M2 is 169.497 mm, the condition (7) is satisfied.

In order to suppress the intensity of flare light, a stop may be disposed in the vicinity of the lens surface or in the intermediate image position in the photographing optical system. It is also effective to set a necessary minimum aperture for the frame that holds the lens so that excess flare light does not enter the image sensor.

The aberration status of this embodiment is as shown in FIG. 22 (magnification 0.35) and FIG. 23 (magnification 4).

FIG. 8 and Table 6 show the seventh embodiment of the present invention, which is still another example of the fourth embodiment. As in the fourth embodiment, the fixed group FG and a plurality of sets of moving groups VG are used, and the magnification of the photographing optical system is converted by exchanging the moving groups.

Lens data of the photographing optical system of the seventh embodiment is as shown in Table 6. The lens data in Table 6 includes the objective lens OB (r _{2 to} r ₂₈ ), the virtual surface (r ₂₉ ) indicating the position where the objective lens is mounted, and the imaging lens IML (r _{30 to} r ₃₂ ). ing. Further, it is assumed that there is water as immersion liquid at the tip of the objective lens OB.

Subsequent to the mirror M1 (r ₃₃ ), a first photographing unit having a magnification of 0.35 is disposed. The first photographing unit includes a first lens group LG1 (r _{34 to} r ₃₆ ), an aperture S (r ₄₀ ), a second lens group LG2 (r _{41 to} r ₄₃ ), and a third lens group LG3 (r _44).
~r ₄₈₎ consisting of. In this embodiment, in order to perform differential interference observation, polarizing plate A
N (r _{37 to} r ₃₈ ) is arranged in the optical path. The intermediate image MI (r ₃₉ ) is the first
It is formed between the lens group LG1 and the second lens group LG2. Then, a mirror M2 (r ₄₉ ) is arranged following the third lens group LG3, and a final image IMG (r ₅₀ ) is formed.

Here, among the lens groups of the first photographing unit, the first lens group LG1 is a fixed lens group FG, and the first lens group LG1 and the third lens group LG3 are moving lens groups VG.
(1). Table 6 also describes lens data of a third photographing unit with a magnification of 4 and a second photographing unit with a magnification of 2. However, the first to third
Since the first lens group LG1 of the photographing unit is a common fixed lens group FG, what is shown below the first photographing unit in FIG. 8 is the third photographing unit and the second photographing unit. These are the moving lens groups VG (3) and VG (2). Note that the position of the intermediate image (MI) is between the third lens group LG3 and the fourth lens group LG4 in the third imaging unit, and between the first lens group LG1 and the second lens group LG2 in the second imaging unit. Between. (The intermediate image position in the third photographing unit is shown in FIG. 8, but there is no data indicating the intermediate image in the lens data.)
Also in the present embodiment, the first movement group VG (1) and the third movement group VG (3)
By exchanging, the magnification of the photographing optical system can be changed from 0.35 times to 4 times. Further, by exchanging the first moving group VG (1) and the second moving group VG (2), the magnification of the photographing optical system can be changed from 0.35 times to 2 times.

Also, as shown in FIG. 9, when the second lens group and the third lens group of the first photographing unit are moved, the photographing magnification can be changed from 0.25 times to 1 time. That is, in FIG. 9, (A) is 0.25 times, (B) is 0.35 times, and (C) is 0.
. 5 times, (D) is the arrangement position of each lens group at 1 time. The lens data at this time is as shown in (A), (B), (C), and (D) of Table 6-1. Table 6
Surfaces corresponding to surface numbers 1 and 2 in -1 are not shown in FIG.

As described in Table 6-2, the imaging optical system according to the seventh embodiment also includes conditions (2), (4), conditions(
8-2), condition (9), and condition (10) are satisfied.

Further, the interval L between P1 and P2 in the first configuration is 284 mm and the condition (7
) Is satisfied.

In the seventh embodiment as well, it is preferable to dispose a stop on the lens surface and the intermediate image position in the photographing optical system in order to suppress the intensity of flare light. The minimum effective diameter is set in the lens holding frame so that extra flare light does not enter the image sensor.

The aberration diagrams in the seventh embodiment are shown in FIG. 24 (magnification 0.35),
This is as shown in FIG. 25 (magnification 4).

FIG. 10 shows an eighth embodiment of the present invention, which is an example of another lens barrel of the present invention. The same components as those in FIG. The second lens barrel of the present invention has a configuration in which the ND filter 12 is disposed in the low magnification photographing unit A as shown in FIG. FIG. 11 shows the configuration of the photographing optical system used in the lens barrel of the eighth embodiment. However, there is no lens data.

If an ND filter is arranged in the low magnification side photographing unit like this lens barrel, the image strength when using a high magnification photographing unit and the image strength when using a low magnification photographing unit are used. It is possible to reduce the difference.

The intensity of the image is proportional to the square of the numerical aperture of the light beam at the final image position (hereinafter referred to as the exit-side numerical aperture). In the present embodiment, the exit-side numerical aperture of the low-magnification photographing unit A is 0.04, and the exit-side numerical aperture of the high-magnification photographing unit B is 0.0113. Therefore, in order to make the intensity of the image photographed by the low-magnification photographing unit A and the image photographed by the high-magnification photographing unit B equal, the density (transmittance T) of the ND filter may be set to the following value.

T = (0.04 / 0.0113) = 12.5
As described above, when the ND filter having a transmittance of about 12.5% is arranged in the low-magnification photographing unit A, the image intensity when the photographing unit is replaced, that is, the brightness can be made substantially equal. Therefore, the brightness of the image obtained by the first imaging device 5 is substantially constant regardless of replacement of the photographing unit. Therefore, it is not necessary to perform brightness and contrast processing each time the photographing unit is replaced, and the operability is greatly improved.

Further, since the ND filter is disposed in the effective light beam, the magnification and the imaging position change when the ND filter is inserted / removed or an ND filter having a different thickness is inserted. In such a case, the magnification and the imaging position can be compensated by changing the positional relationship between the second lens group and the third lens group. At this time, the aberration of the photographing unit hardly changes.

FIG. 12 shows a ninth embodiment of the present invention, which is still another example of the lens barrel of the present invention. The same components as those in FIG. 5 are denoted by the same reference numerals, and description thereof is omitted. The lens barrel of the ninth embodiment includes a photographic optical system 13 in the optical path deflected by the deflecting mirror M2.
Is arranged. That is, in the lens barrel of the ninth embodiment, as shown in FIG. 12, the intermediate image MI formed by the imaging lens IML is located in the optical path deflected by the deflection mirror M2. Following this intermediate image MI, a photographing optical system 13 is arranged.

FIG. 13 and Table 7 show the photographing optical system used for the lens barrel of the present embodiment. The lens data in Table 7 includes the objective lens OB (r _{2 to} r ₂₈ ), the virtual surface (r ₂₉ ) indicating the position where the objective lens is mounted, the virtual surface (r ₃₀ ), and the mirror MI (r ₃₁ ).
, Polarizer AN (r ₃₃ ~r _34), an imaging lens IML (r ₃₅ ~r _37), a mirror M2 (
r ₃₈ ) is included. Further, it is assumed that there is water as immersion liquid at the tip of the objective lens OB. The intermediate image MI (r ₃₉ ) is formed between the mirror M2 and the photographing unit.

The lens barrel of the present embodiment includes an optical system from the mirror M1 to the final image IMG. The photographing optical system 12 includes a first photographing unit and a second photographing unit, and both are arranged on the optical path on the side reflected by the mirror M2. In FIG. 13, the first photographing unit is arranged in the optical path. A second photographing unit is shown on the left side of the first photographing unit.

The first photographing unit is a positive meniscus lens first lens group LG1 (r ₄₀ to
r ₄₁ ), a second lens group LG2 (r _{42 to} r ₄₄ ) of a negative cemented meniscus lens in which a biconvex lens and a biconcave lens are cemented, a cemented lens in which the biconcave lens and the biconvex lens are cemented, and a positive lens. It is composed of a third lens group LG3 (r ₄₆ ~r _50). The first photographing unit is configured such that the pupil conjugate position of the objective lens is between the second lens group LG2 and the third lens group LG3, and the stop S (r
₄₅ ) is arranged.

The second photographing unit includes a first lens group LG1 (r _{40 to} r ₄₄ ) including a positive lens, a positive cemented lens obtained by cementing a biconvex lens and a biconcave lens, a biconcave lens, and a biconvex lens. the second lens group LG2 of the joined positive cemented lens (r ₄₆ ~r
₄₈₎ it is composed of a third lens unit having a positive meniscus lens LG3 (r ₄₉ ~r _50). The second photographing unit includes a first lens group LG1 and a second lens group L.
An aperture stop S (r ₄₅ ) is provided between G2 and G2.

Further, as shown in Table 7-1, in the lens data of Table 7, (A) is the first photographing unit with a low magnification of 0.35, and (B) is the second photographing unit with a magnification of 2. .86 times. In Table 7, it can be seen that the numerical values of the lens surfaces 39 to 50 in (A) are the same as the numerical values of the lens surfaces 50 to 39 in (B). That is, the second photographing unit is obtained by inverting the first photographing unit.
Here, the inversion is to rotate 180 ° around one point on the optical axis.

As described above, the imaging optical system used in the lens barrel of the present embodiment reverses the same imaging unit, thereby reducing the low magnification (0.35 times) and the high magnification (2.86 times).
It is an optical system that can obtain the final image of Note that the position of the intermediate image MI is determined by the imaging lens IML, and an imaging element is disposed at the position of the final image IMG. Therefore, it is necessary to prevent the position of the final image IMG from changing even if the photographing unit is reversed.

Therefore, in the case of the first imaging unit, the distance (d ₃₉ = 44.4725) from the intermediate image MI (r ₃₉ ) to the front surface (r ₄₀ ) of the first lens group, and the rear end of the third lens group The distance from the surface (r ₄₉ ) to the final image IMG (r ₅₀ ) is substantially equal. (
Naturally, the same result is obtained in the case of the second photographing unit. )
One conjugate image of the pupil of the objective lens is formed by the optical system from the objective lens OB to the imaging lens IML, and another is formed by the optical system from the objective lens OB to the photographing unit. When the former is the entrance pupil and the latter is the exit pupil, in the present embodiment, the absolute value of the distance from the position of the intermediate image MI to the entrance pupil position and the distance from the final image to the exit pupil position are substantially equal. . Also, the measurement reference position for the distance to the entrance pupil position is the intermediate image position, the measurement reference position for the distance to the exit pupil position is the final image position, and the value when measured from the intermediate image position toward the final image position is positive. Then, the distance value to the entrance pupil position is opposite to the distance value to the exit pupil position.
(For example, if the distance to the entrance pupil position is positive, the distance to the exit pupil position is negative.)
As described above, in the photographing unit according to the present embodiment, the distance to the intermediate image and the distance to the final image are substantially equal, and the condition (19) or (19 ′) is satisfied. Therefore, even if the photographing unit is inverted, the imaging relationship regarding the image and the pupil does not change. Therefore, the optical performance does not change greatly except that the magnification changes before and after inversion.

In addition, since a large space is required to perform inversion, the lens barrel tends to be large. Therefore, as described in the embodiments so far, if the first photographing unit and the second photographing unit are prepared and replaced, the enlargement of the lens barrel can be prevented. Note that the exchange mechanism includes rotation by a drum mechanism or movement by a slide mechanism.

Further, as described above, the diaphragm may be changed in accordance with the magnification.
In addition, it is possible to arrange the ND filter in a low-magnification photographing unit and to give the optical path splitting element characteristics that enable infrared light observation and visible light observation.

The photographing optical system used for the lens barrel of the ninth embodiment satisfies the conditions (14), (15), (16), (17), and (18) as shown in Table 7-1. .

The aberration diagrams of the imaging optical system shown in FIG. 12 are shown in FIG. 26 (magnification 0.35) and FIG.
(Magnification 2.86)

Also, in the lens barrel of the ninth embodiment, it is preferable to dispose a stop near the lens surface and in the intermediate image position in the photographing optical system in order to suppress flare light. It is also effective to set the minimum effective diameter necessary for the lens holding frame so that excess flare light does not enter the image sensor.

Each of the embodiments of the photographic optical system of the present invention described above has a configuration that places importance on suppressing the generation of flare light and preventing the flare light from reaching the final image position.

On the other hand, even if flare light is generated, if the light intensity at the final image position is reduced, the image of the specimen can be further observed with good contrast. Therefore, it is preferable that the condition (7) is satisfied in each embodiment of the present invention.

Here, Tables 8 to 12 show data related to the condition (7). Table 8 is the second
It is the data regarding the imaging | photography optical system of embodiment. Among these, Table (A) extracts all the surfaces that may be involved in the generation of flare light. Table (A)
The first reflection surface is an air contact surface that reflects incident light toward the objective lens, and the second reflection surface is an air contact surface that reflects light reflected by the first reflection surface toward the final image side. It is. Further, θ is the incident angle of the axial light beam at the final image position of the light (that is, flare light) reflected toward the final image side by the second reflecting surface.

Here, the number of each reflecting surface corresponds to the surface number of the lens data in Table 2. In the table, for example, 4.00E-0.6 is 4.00 × 10 ⁻⁶ . Further, although the number 0 is written on the second reflecting surface of Table (A), the lens data of Table 2 does not have the surface number 0. This corresponds to the surface number 1 of the lens data in Table 2 corresponding to the number 0 of the second reflecting surface.

Table (B) is obtained by extracting combinations of reflecting surfaces having a relatively large value of {(F / FO) · sin θ} ² from Table (A). For example, 9-0 indicates that the first reflecting surface is nine and the second reflecting surface is zero. As can be seen from Table (B), the values of {(F / FO) · sin θ} ² are all smaller than 0.005. Therefore, the photographing optical system of the second embodiment satisfies the condition (17). In addition, {(
F / FO) · sin θ} ² corresponds to the absolute value of the light intensity.

Table (C) shows the intensity distribution of the flare light as numerical values, and the flare light is due to the combination of the reflecting surfaces shown in Table (B). Here, the numerical value in increments of 0.2 at the top represents the image height ratio. The final image actually formed has an image height of 5.5 mm.

In this table (C), for example, when the reflection surface combination is 9-4, the intensity from the image height ratio 0 to the image height ratio 1 is 1 to 0.7. This indicates that the intensity of the flare light is not spot-like but uniform from the center of the visual field to the periphery. On the other hand, when the reflection surface combination is 7-2, the intensity after the image height ratio of 0.4 is 0. This indicates that the intensity of flare light is generated in a spot shape. However, in this case, the value of {(F / FO) · sin θ} ² is 9-4.
One order of magnitude smaller than Therefore, since the light intensity itself is small, there is no problem even if the shape is a spot shape. As described above, the photographing optical system according to the second embodiment is an optical system that satisfies the condition (17). Therefore, spot-like flare does not occur or even if it occurs, the intensity is very small. . Therefore, the specimen can be observed with good contrast.

Next, Table 9 shows data related to the photographing optical system of the third embodiment. Table (A
), (B), and (C) have the same meanings as described in Table 8.

This table (C) also shows that the flare light is non-spotted or has a low intensity even in the case of a spot.

Table 10 shows data relating to the photographing optical system of the sixth embodiment. In the sixth embodiment, the photographing optical system includes two photographing units, and the magnification is changed by exchanging these two photographing units. Of the two photographing units, one photographing unit is a low magnification optical system, and the other photographing unit is a high magnification optical system.
For this high magnification optical system, a 2 × or 4 × optical system is used.

In Table 10, Tables (A), (B), and (C) are data relating to the 2 × photographing unit, and Tables (D), (E), and (F) are data relating to the 4 × photographing unit. The meaning of each data is as described in Table 8. Also in this table (C) or (F), it is indicated that the flare light is non-spotted or has a low intensity even in the case of spot-like.

Table 11 shows data relating to the photographing optical system according to the seventh embodiment. In the seventh embodiment, as in the sixth embodiment, the photographing optical system includes two photographing units. Therefore, similarly to Table 10, data at 2 times and 4 times are shown.

In Table 11, Tables (A), (B), and (C) are data relating to a 4 × photographing unit, and Tables (D), (E), and (F) are data relating to a 2 × photographing unit. The meaning of each data is as described in Table 8. Also in this table (C) or (F), it is indicated that the flare light is non-spotted or has a low intensity even in the case of spot-like.

Table 12 shows data related to the photographing optical system of the ninth embodiment. In the ninth embodiment, there is basically one photographing optical system, and this photographing optical system is inverted to obtain different magnifications. Therefore, data of two magnifications (β = 0.35 and β = 2.86) are described in Table (A) of Table 12. Table (A) shows {(F / FO)
• The value of sin θ} ² is not described.

Tables (B) and (C) are data when the magnification is 0.35, and Tables (D) and (E) are data when the magnification is 2.86. Any of the tables (B) and (C) described in Table 8
The data has the same meaning as In Table 10 {(F / FO) · sinθ} not ^2, but has a ^{{β · sinθ} 2 (F} / FO) = from a beta {(F
/ FO) · sin θ} ² .

Table (C) or (E) also shows that the flare light is non-spotted or has a low intensity even in the case of a spot.

As shown in Tables 8 to 12, the photographing optical system according to the embodiment of the present invention is
All satisfy the condition (7) and the intensity of the flare light is sufficiently reduced.

As described above, in addition to the invention described in the claims, the present invention can also achieve the object of the present invention described in the following items.

(1) A lens barrel used in a microscope including an objective lens and an imaging lens, and includes an optical path splitting element and a positive cemented lens including a positive lens and a negative lens in an optical path reflected by the optical path splitting element. A first lens group; a second lens group having a positive refractive power with a convex surface facing the first lens group; and a third lens group having a positive refractive power including a cemented lens. A lens barrel comprising an imaging optical system in which an intermediate image is formed between a lens group and the second lens group and satisfies the following conditions (3) and (4):

(3) 1.8 ≦ F ′ / FO ≦ 2.5
(4) 0.15 ≦ D2 / D ′ ≦ 0.4
(2) A lens barrel used in a microscope having an objective lens and an imaging lens, and includes an optical path splitting element and a positive cemented lens composed of a positive lens and a negative lens in the optical path reflected by the optical path splitting element. A first lens group; a second lens group including a negative cemented lens including a positive lens and a negative lens; a third lens group including a positive cemented lens including a positive lens and a negative lens; and the third lens group. A photographic optical system having a fourth lens group including a positive lens having a convex surface on the side, wherein an intermediate image is formed between the third lens group and the fourth lens group, and satisfies the following condition (5): A lens barrel comprising a system.

(5) 3 ≦ F ″ / FO ≦ 6
(3) A lens barrel used in a microscope having an objective lens and an imaging lens, having a photographing optical system in the lens barrel, and the photographing optical system is inserted into and removed from a fixed group that is always fixed in the optical path. The fixed group includes a positive cemented lens composed of a positive lens and a negative lens, the moving group includes a first moving group and a second moving group, the first group The moving group includes a second lens group including a negative cemented meniscus lens having a concave surface facing the fixed group side, and a third lens group including a cemented lens, and the intermediate group between the fixed group and the second lens group. The second moving group includes a second lens group including a positive lens having a convex surface directed toward the fixed lens group and a third lens group including a cemented lens, and is configured to form an image. An intermediate image is formed between two lens groups, and the first moving group and the second moving group are formed. The magnification is converted by exchanging the moving group, and an optical system composed of the fixed group and the first moving group satisfies the following conditions (1) and (2), and the fixed group and the first group The optical system composed of two moving groups has the following conditions (3) and (4)
A lens barrel characterized by satisfying the above.

(1) 0.25 ≦ F / FO ≦ 1.5
(2) 0.15 ≦ D1 / D ≦ 0.4
(3) 1.8 ≦ F ′ / FO ≦ 2.5
(4) 0.15 ≦ D2 / D ′ ≦ 0.4
(4) A lens barrel used in a microscope having an objective lens and an imaging lens, having a photographic optical system in the lens barrel, and the photographic optical system is inserted into and removed from a constantly fixed group in the optical path. The fixed group includes a positive cemented lens composed of a positive lens and a negative lens, the moving group includes a first moving group and a third moving group, The moving group includes a second lens group including a cemented meniscus negative lens having a concave surface facing the fixed lens group, and a third lens group including a cemented lens, and the fixed group and the second lens group An intermediate image is formed between the second lens group including a negative cemented lens including a positive lens and a negative lens, and a positive cemented lens including a positive lens and a negative lens. And a positive lens having a convex surface on the third lens group side And an intermediate image is formed between the third lens group and the fourth lens group, and the first moving group and the third moving group The magnification is changed by exchange, and an optical system composed of the fixed group and the first moving group satisfies the following conditions (1) and (2), and the fixed group and the third moving group: A lens barrel characterized in that the optical system configured by satisfies the following condition (5).

(1) 0.25 ≦ F / FO ≦ 1.5
(2) 0.15 ≦ D1 / D ≦ 0.4
(5) 3 ≦ F ″ / FO ≦ 6
(5) An imaging optical system according to claim 1, wherein an aperture stop for limiting the numerical aperture of the objective lens is provided in the imaging optical system.

(6) The lens barrel according to claim 6, wherein an aperture stop for limiting the numerical aperture of the objective lens is provided in the photographing optical system.

(7) The photographing optical system according to claim 4 or 5, wherein the first moving group is provided with an aperture stop for limiting the numerical aperture of the objective lens. Optical system.

(8) The lens barrel described in (3) or (4) above, wherein an aperture stop for limiting the numerical aperture of the objective lens is provided in the first moving group.

(9) The photographing optical system according to (5), wherein an optical element that attenuates the amount of light is disposed in the photographing optical system.

(10) The lens barrel described in (6) above, wherein an optical element that attenuates the amount of light is arranged in the photographing optical system.

(11) The photographic optical system according to (7), wherein an optical element that attenuates the amount of light is arranged in the optical system having the fixed group and the first moving group.

(12) The lens barrel according to (8), wherein an optical element that attenuates the amount of light is arranged in an optical system having the fixed group and the first moving group.

(13) In the photographing optical system described in (9), the optical element for attenuating the light amount is detachably arranged with respect to the optical path, and the third lens group is movable along the optical axis. An imaging optical system characterized by

(14) In the lens barrel described in (10), the optical element for attenuating the light amount is disposed so as to be insertable / removable with respect to the optical path, and the third lens group is movable along the optical axis. A characteristic lens barrel.

(15) In the photographing optical system described in (11), an optical element that attenuates the amount of light is disposed so as to be detachable with respect to the optical path, and the third lens group is movable along the optical axis. An imaging optical system characterized by

(16) In the lens barrel described in (12), the optical element for attenuating the light amount is disposed so as to be insertable / removable with respect to the optical path, and the third lens group is movable along the optical axis. A characteristic lens barrel.

(17) In the photographing optical system according to (5) or (11), an optical element for attenuating the light amount is disposed so as to be detachable with respect to an optical path, and a lens group disposed closest to the final image is provided. An imaging optical system characterized by being movable along an optical axis.

(18) In the lens barrel described in (6) or (12), an optical element that attenuates the amount of light is disposed so as to be detachable with respect to the optical path, and a lens group disposed at a position closest to the final image is provided. A lens barrel that is movable along the optical axis.

(19) A lens barrel according to claim 6, wherein the optical path splitting element is arranged in the lens barrel described in (1), (2), (3), (4).

(20) The lens barrel according to (19), wherein the optical path dividing element is positioned on an optical axis of the microscope in a state where the lens barrel is attached to the microscope.

(21) In the lens barrel described in (19), the optical path dividing element is disposed between the imaging lens and the first lens group in a state where the lens barrel is attached to a microscope. A lens barrel.

(22) The lens barrel according to (19), wherein the optical path dividing element has a spectral characteristic of reflecting light in an infrared region and transmitting light in a visible region.

(23) Claim 6 of the claims or the above (1), (2), (3)
Or the lens barrel described in the item (4), further including an imaging element and a deflection element, wherein the deflection element is disposed between the imaging element and a lens group disposed closest to the final image position; The optical axis determined by the photographing optical system is deflected in the orthogonal direction, and the following condition (6
) Satisfying the above).

(6) 150mm ≦ L ≦ 300mm
Here, L is the distance between the points P1 and P2, P1 is the point where the optical axis of the objective lens intersects with the optical path dividing element, and P2 is the point where the optical axis of the photographing optical system intersects with the deflection element.

(24) Claim 6 of the claims or the above (1), (2), (3)
Or the lens barrel described in the item (4), wherein the following condition (6) is satisfied.

(7) {(F / FO) · sin θ} ² ≦ 0.005
Where F is the focal length of the photographic optical system, FO is the focal length of the imaging lens, and θ is reflected to the objective lens side by an arbitrary air contact surface between the objective lens and the final image. The incident angle at the final image position of the axial light beam reflected to the final image side by an air contact surface different from the surface.

(25) The photographing optical system according to claim 3 of the claims or the above (
2. A photographic optical system or a lens barrel that satisfies at least one of the following conditions (8-1) and (8-2):

(8-1) 0.25 ≦ | R2G | /D2G≦0.9
(8-2) 1.5 ≦ | R2G | / D2G ≦ 15
Where R2G is the radius of curvature of the air contact surface on the intermediate image side in the second lens group, and D2
G is the distance from the air contact surface on the intermediate image side to the intermediate image.

(26) The photographing optical system according to claim 3 of the claims or the above (
2. A photographic optical system or barrel that satisfies the following condition (9) in the barrel described in the section 2).

(9) 0.7 ≦ R3G / D3G ≦ 1.2
Where R3G is the radius of curvature of the air contact surface with the convex surface facing the second lens group side of the third lens group, and D3G is the distance from the air contact surface to the intermediate image.

(27) In the photographing optical system according to claim 2 of the claims, the following condition (
10) A photographing optical system satisfying the above (10).

(10) 0.8 ≦ | R22 | /D22≦1.6
Where R22 is the radius of curvature of the air contact surface with the convex surface facing the third lens group in the second lens group, and D22 is the air contact with the convex surface facing the third lens group in the second lens group from the intermediate image. The distance to the surface.

(28) The lens barrel described in the above item (1), which satisfies the following condition (10).

(10) 0.8 ≦ R22 / D22 ≦ 1.6
(29) A photographing optical system used in a microscope including an objective lens and an imaging lens, and a second lens including a first lens group including a positive meniscus lens and a negative cemented meniscus lens in which a biconvex lens and a biconcave lens are cemented. A cemented lens obtained by cementing a group, a biconcave lens, and a biconvex lens, and a third lens including a positive lens, and further comprising a diaphragm provided between the second lens group and the third lens group. Arranged at a position conjugate with the pupil position of the objective lens, an intermediate image is formed between the imaging lens and the first lens group, and a final image is formed through the first to third lens groups. An imaging optical system satisfying the conditions (11), (12), (13), and (19).

(11) 0.7 ≦ D (I1) / D (3I) ≦ 1.3
(12) 0.35 ≦ D (13) / D (I) ≦ 0.65
(13) 0.2 ≦ | β | ≦ 0.5
(19) P _in = −P _out
Where D (I1) is the distance from the intermediate image to the tip of the first lens group, and D (3I)
Is the distance from the rear end of the third lens group to the final image, D (13) is the distance from the front end of the first lens group to the rear end of the third lens group, and D (I) is the distance from the intermediate image to the final image. Distance, β
The distance from the intermediate image to the magnification of the optical system to the final image, P _in the entrance pupil position of the intermediate image position (pupil position of the objective lens projected by the objective lens and the imaging lens), P
_out is a distance from the final image position to the exit pupil position (the pupil position of the objective lens projected by the objective lens, the imaging lens, and the photographing optical system).

(30) A lens barrel used in a microscope having an objective lens and an imaging lens, wherein the photographing optical system includes a first lens group including a positive meniscus lens, and a negative cemented meniscus lens in which a biconvex lens and a biconcave lens are cemented. A second lens group, a cemented lens obtained by cementing a biconcave lens and a biconvex lens, a third lens including a positive lens, and a diaphragm provided between the second lens group and the third lens group, A diaphragm is disposed at a position conjugate with the pupil position of the objective lens, an intermediate image is formed between the imaging lens and the first lens group, and a final image is formed via the first to third lens groups. And a lens barrel that satisfies the following conditions (14), (15), (16), and (19 ′).

(14) 0.7 ≦ D ′ (I1) / D ′ (3I) ≦ 1.3
(15) 0.35 ≦ D ′ (13) / D ′ (I) ≦ 0.65
(16) 0.2 ≦ | β ′ | ≦ 0.5
(19 ') P _in ' = -P _out '
(31) A photographing optical system used in a microscope having an objective lens and an imaging lens, a first lens group including a positive lens, a positive lens, and a biconcave lens including a positive lens and a cemented lens of a biconvex lens and a biconcave lens. And a second lens group including a negative cemented meniscus lens of a biconvex lens, and a third lens group including a positive meniscus lens having a concave surface facing the second lens group, and an intermediate image is formed between the imaging lens and the second lens group. A final image is formed between the first lens group and the first to third lens groups, and the following condition (14
), (15), (16) and (19 ′).

(14) 0.7 ≦ D ′ (I1) / D ′ (3I) ≦ 1.3
(15) 0.35 ≦ D ′ (13) / D ′ (I) ≦ 0.65
(16) 0.2 ≦ | β ′ | ≦ 0.5
(19 ') P _in ' = -P _out '
(32) A lens barrel used in a microscope having an objective lens and an imaging lens, in which the photographing optical system is a positive lens, a first lens group including a cemented lens of a biconvex lens and a biconcave lens, and a negative of the biconcave lens and the biconvex lens. A second lens group including a cemented meniscus lens and a third lens group including a positive meniscus lens having a concave surface on the second lens group side, and an intermediate image is formed between the imaging lens and the first lens group. A final image is formed through the first to third lens groups, and the following conditions (14), (15), (
16) A lens barrel characterized by satisfying (19 ′).

(14) 0.7 ≦ D ′ (I1) / D ′ (3I) ≦ 1.3
(15) 0.35 ≦ D ′ (13) / D ′ (I) ≦ 0.65
(16) 0.2 ≦ | β ′ | ≦ 0.5
(19 ') P _in ' = -P _out '
(33) In the photographing optical system described in (31) above, or (2)
7) A photographing optical system or a lens barrel satisfying the following condition (17):

(17) 0.5 ≦ | R3 | /D3≦2.0
Where R3 is the radius of curvature of the surface of the third lens group facing the second lens group, and D3 is the third radius.
This is the distance from the surface on the second lens group side of the lens group to the final image position.

(34) In the photographing optical system described in the above (31), the following condition (18)
An imaging optical system characterized by satisfying

(18) 0.5 ≦ (| RA | + | RB |) / (| L1 | + | L2 |)
≦ 1.5
Where RA is the radius of curvature of the lens surface with the concave surface facing the second lens group of the first lens group, L1 is the distance from this surface to the pupil conjugate position, and RB is the second lens group and the third lens group.
The radius of curvature of the lens surface with the concave surface facing the first lens unit of the lens unit, L2 is the distance from this surface to the pupil conjugate position.

(35) The lens barrel described in the above item (32), which satisfies the following condition (18):

(18) 0.5 ≦ (| RA | + | RB |) / (| L1 | + | L2 |)
≦ 1.5

It is a figure which shows the imaging optical system of the 1st Embodiment of this invention, (A) A structure when a magnification is 0.25 times, (B) A structure when a magnification is 0.35 times, (C) A configuration when the magnification is 0.5 times, and (D) a configuration when the magnification is 1 time. The figure which shows the structure of the imaging optical system of the 2nd Embodiment of this invention. The figure which shows the structure of the imaging optical system of the 3rd Embodiment of this invention. The figure which shows the structure of the imaging optical system of the 4th Embodiment of this invention. The figure which shows the optical apparatus provided with the lens-barrel of the 5th Embodiment of this invention The figure which shows the structure of the imaging optical system of the 6th Embodiment of this invention. It is a figure which shows the low magnification imaging | photography unit used for the imaging optical system of 6th Embodiment, (A) The structure when a magnification is 0.25 time, (B) When a magnification is 0.35 times Configuration, (C) Configuration when magnification is 0.5 times, and (D) Configuration when magnification is 1 times. The figure which shows the structure of the imaging optical system of the 7th Embodiment of this invention It is a figure which shows the low magnification imaging unit used for the imaging optical system of 7th Embodiment, (A) The structure when a magnification is 0.25 times, (B) When a magnification is 0.35 times Configuration, (C) Configuration when magnification is 0.5 times, and (D) Configuration when magnification is 1 times. The figure which shows the optical apparatus provided with the lens-barrel of the 8th Embodiment of this invention. The figure which shows the structure of the imaging optical system used with the lens-barrel of the said 8th Embodiment. The figure which shows the structure of the lens-barrel of the 9th Embodiment of this invention. The figure which shows the structure of the imaging optical system used with the lens-barrel of the said 9th Embodiment. Aberration curve diagram of the photographing optical system with a magnification of 0.25 according to the first embodiment Aberration curve diagram of the photographing optical system with a magnification of 0.35 according to the first embodiment Aberration curve diagram of the photographing optical system of magnification 2 of the first embodiment Aberration curve diagram of the photographing optical system of magnification 4 of the first embodiment Aberration curve diagram of the photographing optical system of magnification 2 of the second embodiment Aberration curve diagram of the photographing optical system of magnification 4 of the second embodiment Aberration curve diagram of photographing optical system with magnification of 0.25 according to the fourth embodiment Aberration curve diagram of the photographing optical system of magnification 4 of the fourth embodiment Aberration curve diagram of photographing optical system with magnification 0.2 of the sixth embodiment Aberration curve diagram of photographic optical system with magnification 4 of the sixth embodiment Aberration curve diagram of photographing optical system with magnification of 0.25 according to the seventh embodiment Aberration curve diagram of photographing optical system with magnification 4 of the seventh embodiment Aberration curve diagram of photographing optical system with magnification of 0.25 according to the ninth embodiment Aberration curve diagram of photographic optical system with magnification 4 of 9th embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Objective lens 2 Optical path dividing element 3 Lens barrel 4 ≠ P3 Imaging optical system 5 First imaging device 6 Intermediate magnification unit 7 Eyepiece optical system 8, 8 'Second imaging optical system 9 Second imaging device 10 Sample 11 Transmission illumination system 12 ND filter 20 Epi-illumination system 30 Image processing device 40 Display device A, B Imaging unit AN Polarizing plate FG Fixed lens group IML Imaging lens LG1 First lens group LG2 Second lens group LG3 Third lens group LG4 First 4 lens group M1 optical path dividing element M2 mirror MI intermediate image IMG final image OB objective lens PU objective lens pupil S aperture stop VG moving lens group

Claims (4)

A objective lens and the imaging lens microscope imaging optical system used for the co equipped with this imaging optical system, the disposed behind the microscope imaging lens, a positive comprising a positive lens and a negative lens A first lens group including a cemented lens, a second lens group including a negative cemented lens including a positive lens and a negative lens, and a third lens group including a positive cemented lens including a positive lens and a negative lens; A fourth lens group including a positive lens having a convex surface directed toward the third lens group; and in combination with the microscope, between the third lens group and the fourth lens group of the photographing optical system. An imaging optical system that is configured to form an intermediate image and satisfies the following condition (5).
(5) 3 ≦ F ″ / FO ≦ 6
Where F ″ is the combined focal length of the optical system from the imaging lens to the fourth lens group, and FO is the focal length of the imaging lens. A objective lens and the imaging lens microscope imaging optical system used for the co equipped with this imaging optical system, the disposed behind the microscope imaging lens, is always fixed in the optical path of the optical system A fixed group, and a movable group that can be inserted into and removed from the optical path.The fixed group includes a first lens group that includes a positive cemented lens including a positive lens and a negative lens, and the movable group includes: The first moving group includes a first moving group and a third moving group, and the first moving group includes a negative cemented meniscus lens having a concave surface facing the fixed group, and is joined to the second lens group of the first moving group . A third lens group of the first moving group including a lens, and in a combination with the microscope, between the first lens group of the photographing optical system and the second lens group of the first moving group . An intermediate image is formed, and the third moving group includes a positive lens and a negative lens. A third third third lens group moving group comprising a positive cemented lens consisting of a second lens unit of the mobile group and the positive lens and the negative lens including a negative cemented lens composed of, movement of the third A fourth lens group including a positive lens having a convex surface facing the third lens group side of the group, and in combination with the microscope, a third lens group of the third moving group of the photographing optical system ; An optical system configured to form an intermediate image between the fourth lens group and converting the magnification by converting the first moving group and the third moving group; An optical system having the fixed group and the first moving group satisfies the following conditions (1) and (2), and the optical system having the fixed group and the third moving group satisfies the following condition (5) system.
(1) 0.25 ≦ F / FO ≦ 1.5
(2) 0.15 ≦ D1 / D ≦ 0.4
(5) 3 ≦ F ″ / FO ≦ 6
Where F is the combined focal length of the optical system from the imaging lens to the third lens group of the first moving group of the photographic optical system having the first moving group , and F ″ is the imaging lens. The combined focal length of the optical system to the fourth lens group of the photographing optical system having the third moving group, FO is the focal length of the imaging lens, and D1 is the photographing optical system having the first moving group. The distance from the rearmost lens surface of the first lens group to the intermediate image position, D is the first optical system of the photographing optical system having the first moving group from the frontmost lens surface of the imaging lens . This is the distance to the lens surface on the rearmost side of the third lens group in the moving group . The photographing optical system according to claim 1, wherein an aperture stop for limiting a numerical aperture of the objective lens is provided in the photographing optical system. The photographic optical system according to claim 3, wherein an optical element that attenuates the amount of light is provided in the photographic optical system.

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