JPH10115788A - Hard mirror optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hard mirror optical system having image quality coping with an HDTV camera by providing a relay optical system constituted of an objective optical system and single or plural partial relay optical systems and satisfying a specified condition. SOLUTION: This hard mirror optical system is a system where a part arranged in an insertion part out of an observation optical system includes an objective optical system and a relay optical system in order from an object side and a part positioned in the insertion part out of the relay optical system has at least one partial relay optical system. Then, the objective optical system and the partial relay optical system in the insertion part satisfy the conditions (1) 0.4mm<=Dr <2> /Lr <=0.8mm (2) Do <2> /Lo >=Dr <2> /Lr . Provided that Do is the maximum lens outside diameter of the objective optical system, Lo is the entire length of the objective optical system, Dr is the maximum lens outside diameter of the partial relay optical system, and Lr is the entire length of the partial relay optical system. The number of the partial relay optical systems positioned in the insertion part is set to <=2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an observation optical system for a rigid endoscope.

[0002]

2. Description of the Related Art A rigid endoscope generally has a configuration as shown in FIG. 12, and has an elongated rigid insertion portion 1 for insertion into a cavity such as a living body, and is located outside the cavity when used. And a gripper 2 supported by a hand of a person or a rigid mirror holder. Further, an observation optical system for observing and photographing an image of an object in the cavity is disposed from the inside of the insertion portion to the inside of the grip portion. In the observation optical system, a portion disposed in the insertion portion is provided with an objective optical system 3 which is disposed on the distal end side and forms a real image of the object, and an image formed by the objective optical system 3 is provided in the grip portion. And a relay optical system 4 for transmitting the signal. These objective optical system 3 and relay optical system 4
Are coaxially arranged in an optical system holding tube 5 in the insertion section 1. The portion of the observation optical system disposed in the holding unit 2 is formed of an eyepiece optical system 6 that allows the object image transmitted by the relay optical system 4 to be viewed.

[0003] When a rigid scope is used in an endoscopic surgical operation, video observation is required. Therefore, a television camera for the rigid scope is attached to the eyepiece mount of the grip portion 2 and observation is performed on a television monitor. In the laparoscopic field, in particular, television observation has become indispensable. For this purpose, as shown in FIG. 12, a television camera 9 for a rigid mirror having an imaging optical system 7 and a solid-state imaging device 8 is attached. 1 in the figure
0 is a camera control unit, and 11 is a television monitor.

[0004]

In recent years, the image quality of television cameras used for endoscopic surgery has been remarkably improved.
Three CCDs of about 400,000 pixels for each color of R, G, B
A three-panel television camera that captures one color image using a (charge-coupled device) and a single-panel television camera with 400,000 pixels or more are becoming widespread. These television systems have 40
It has a horizontal resolution of 0 to 700 TV lines. HD
Television cameras based on the technology of TV (high-definition television) and having a resolution of more than 1000 TVs have come to be used in medical sites. This is because, for example, in an endoscopic surgical operation, HDTV technology is useful for extending the operation procedure and improving the safety of a spread procedure. Obviously, observation systems including endoscopes and rigid endoscopes need to improve image quality, and in view of this performance, HDTV cameras for rigid endoscopes will surely spread in the future. This HDTV has C
When a solid-state imaging device such as a CD is used, about 2 million pixels are required.

[0005] The rigid endoscope tends to have a higher image quality as the outer diameter of the insertion portion is larger, and the mainstream of rigid laparoscopes has the outer diameter of the insertion portion as large as 10 mm. However, the current resolution of a rigid laparoscope is limited to being compatible with a three-panel television camera of about 400,000 pixels, even if a thick one with an outer diameter of 10 mm is used. Therefore, HDTV with higher resolution
In the case of a combination of a camera and a rigid scope, the resolution of the rigid scope does not reach the capability of the HDTV camera, so that the capability of the HDTV camera cannot be exhibited.

Japanese Patent Laid-Open No. 7-537 discloses a conventional example which describes the correlation between the optical system of a rigid endoscope and the resolution of a television camera.
No. 7 is known. In this gazette, the resolution of the critical resolution is determined by the Rayleigh resolution in a rigid mirror optical system having a variable power optical system. However, this conventional example of the rigid mirror optical system has insufficient resolution for HDTV, and cannot utilize the image quality of HDTV.

[0007] Including the above-mentioned embodiment, no study has been made on the combination of an HDTV camera having a number of pixels of about 2 million pixels of a solid-state imaging device and a rigid mirror. It is not clear whether a rigid mirror optical system capable of fully utilizing the information amount of the HDTV camera can be obtained.

An object of the present invention is to provide a rigid mirror optical system having an image quality compatible with an HDTV camera.

[0009]

According to the present invention, there is provided a rigid endoscope optical system in which a portion of an observation optical system arranged in an insertion portion includes an objective optical system and a relay optical system in order from the object side. The one located in the insertion section in the relay optical system has at least one partial relay optical system, and the objective optical system and the partial relay optical system in the insertion section satisfy the following conditions (1) and (2).
Is satisfied.

[0010] ^{_{(1) 0.4mm ≦ D r 2}} / L r ≦ 0.8mm (2) D o 2 / L o ≧ D r 2 / L r However, D _o is the maximum lens diameter of the objective optical system, L _o is the overall length of the objective optical system, the D _r maximum lens diameter portion relay optical system, the L _r is the total length of the portion relay optical system.

In the following, the above-mentioned basic structure is provided, and a condition (1),
The rigid mirror optical system of the present invention that satisfies (2) will be described.

First, the amount of information of an ideal state of a rigid mirror optical system which does not include aberration will be described.

The well-known Rayleigh resolution ε is
It is represented by the following equation (a).

Ε = 0.61λ / NA ′ (a) where λ is the wavelength and NA ′ is the image-side numerical aperture.

In the equation (a), ε corresponds to the radius of the Airy disk, and the intensity distribution of the image at two points separated by ε is such that when the maximum value is 1, the minimum value at the center is 0.7.
When it becomes 4, two points can be separated and distinguished, and usually the reciprocal of ε is defined as the limit resolution. However, as the upper limit of the resolving power of an image observation optical system such as a rigid endoscope,
If the reciprocal of is used, the contrast is too low, which is problematic.
In other words, in the case of an image observation optical system such as a rigid endoscope, it is not sufficient to be able to separate two points, and it is required that a sufficient contrast can be obtained even at the resolution limit by sampling of a television camera combined with this optical system. .

For this reason, the resolution ε _r used for calculating the practical limit resolution of the rigid endoscope must be defined by the following equation (b).

Ε _r = 2ε = 1.22λ / NA ′ (b) This ε _r corresponds to the diameter of an Airy disk, and the intensity distribution of an image at two points separated by ε _r has a maximum value of 1. The minimum value at the time center becomes 0, and not only can two points be separated, but also there is almost no deterioration in contrast.

Therefore, in the present invention, the reciprocal of ε _r is used as the practical limit resolution of the rigid mirror optical system.

The practical limit resolution of the rigid endoscope observation optical system largely depends on the relay optical system. The practical limit resolution of this relay optical system is the numerical aperture (NA _r ) of the relay optical system.
Is determined by Further, when the one obtained by multiplying the practical limit resolution by the size of the image is defined as the one-dimensional information amount Q, the one-dimensional information amount Q of the relay optical system is expressed by the following equation (c).

[0020] _{Q = 0.82NA r · I r /} λ (c) where I _r is a diameter of the image of the relay optical system, the unit of Q is present.

In the above equation, NA _r = 0.0
5, when I _r = 2 mm and λ = 0.65 μm, Q = 126
(Book).

In this case, by projecting 126 or less black-and-white gratings over the entire field of view of the relay optical system, resolution can be achieved with sufficient contrast. However, sufficient contrast cannot be obtained with more black and white gratings. Wavelength λ
Uses the long wavelength side with poor resolution.

When an HDTV camera uses a solid-state imaging device having about 2 million pixels, it usually has about 200 pixels in the horizontal direction.
It has 0 pixels.

A single-chip color CCD having a color filter for each pixel can usually resolve a black-and-white one-pair lattice with three pixels. Therefore, the one-dimensional information amount of the HDTV camera is about 667 in the horizontal direction.

Even if the field of view of the relay optical system in the above calculation example is projected to fill the field of view of the HDTV camera, H
At a frequency lower than the resolution limit of the DTV camera, the contrast of the rigid endoscope is reduced, and the image quality of the HDTV camera cannot be sufficiently utilized.

Therefore, the relay optical system of the rigid endoscope combined with the HDTV camera needs to satisfy the following conditions.

Q = 0.82NA _r · I _r / λ ≧ 667 (d) Here, if λ = 0.65 nm, the above equation (d) becomes as follows.

NA _r · I _r ≧ 0.529 mm (e) In the case of the rigid mirror optical system described in JP-A-7-5377, the F-number is 6.483, and the image size is Is 6.08 mm (image height 3.04 mm). These values are not the relay optics, but the product of the numerical aperture of the optics and the image size is preserved in the optics. Therefore,
Based on the above values, the values of NA _r · I _r of the embodiment of the conventional example are as follows.

NA _r · I _r = 6.08 mm / (2 × 6.483) = 0.469 mm As described above, the embodiment does not satisfy the condition (e).
The contrast deteriorates near the resolution limit of the DTV camera.

The relay optical system of the rigid scope according to the present invention comprises one or a plurality of partial relay optical systems. Here, the partial relay optical system refers to an optical system that performs image transmission only once in the relay optical system in the insertion unit.

The image size I of this partial relay optical system
_r is approximated by the following equation (f), and the numerical aperture NA _r is approximated by the following equation (g).

[0032] _{I r = 0.75D r / L r} (f) NA r = 1.75D r / L r (g) However, D _r is the maximum outer diameter of the lens portion relay optical system (m
m) and L _r are the total length (distance from image to image) of the partial relay optical system (mm).

The size I _r of the image from the formula (f), obtained by the partial relay optical system is found to be proportional to the outside diameter D _r of the lens. Here, the proportionality constant of 0.75 was set so that an image as large as possible could be formed while avoiding vignetting around the field of view of the partial relay optical system.

Further, D _r / L _r in equation (g) is easily derived from the definition of the numerical aperture. The proportional constant of 1.75 is set based on the average refractive index of the partial relay optical system.

In the partial relay optical system, most of the space is usually occupied by glass, and the numerical aperture is increased by a proportion of the refractive index as compared with the case where the partial relay optical system is filled with air. Therefore, the above-mentioned proportionality constant was multiplied.

By substituting equations (f) and (g) into equation (e), the following equation (h) is obtained.

[0037] ^{_{D r 2 / L r ≧ 0.4mm}} (h) D r 2 / L r of the equation (h) is a parameter reflecting the one-dimensional amount of information that can be transmitted in the portion relay optical system. Within the range shown in the formula (h) at a value all parts the relay optical system of this parameter D _r ² / L _r, it is possible to obtain a sufficient one-dimensional information amount capable of handling HDTV as a relay optical system . However this parameter D _r ² / L value of _r is larger than necessary when the aberration correction when too large numerical aperture or the image of the relay optical system lens design becomes difficult. Therefore D _r ² / L _r is preferably within the following range.

[0038] From the above reasons ^{_{D r 2 / L r ≦ 0.8mm}} , the rigid endoscope optical system of the present invention, was the partial relay optical system constituting the relay optical system so as to satisfy the following condition (1).

(1) 0.4 mm ≦ D _r ² / L _r ≦ 0.8 mm If the lower limit of 0.4 mm of the condition (1) is exceeded, the HDTV
The resolution and contrast are not sufficient to cope with the above. The 0.8mm of the upper limit is equal to two times the value of the lower limit value, the numerical aperture of the thus partially relay optical system becomes a value more than twice the lower limit value of D _r ² / L _r If the product of と and the image size is doubled, aberrations will worsen, which is not preferable. That is,
Considering the tertiary aberration, when the numerical aperture is doubled, the lateral aberration of spherical aberration becomes eight times, and when the image size is doubled, the longitudinal aberration of astigmatism becomes four times. These aberrations in the partial relay optical system cannot be corrected well even if the number of lenses is increased or an aspherical surface is employed.

The relay optical system constituting the rigid mirror optical system according to the present invention has been described above. However, if the objective optical system constituting the optical system according to the present invention does not have a sufficient one-dimensional information amount, the relay optical system is required. Cannot utilize the amount of one-dimensional information. Therefore, the objective optical system also needs to have a primary information amount equal to or greater than that of the relay optical system.

Assuming that the maximum outer diameter of the objective optical system is D _o (mm) and the total length of the objective optical system is L _o (mm), _Do ² / L _o is a parameter representing one-dimensional information amount of the objective optical system. is there.

In the objective optical system according to the present invention, the parameter representing the one-dimensional information amount is the following condition for all the partial relay optical systems (for the parameter representing the one-dimensional information amount for all the partial relay optical systems): It is desirable to satisfy the relationship shown in (2).

[0043] (2) D When ^{_{o 2 / L o ≧ D r}} 2 / L r the condition (2) is not satisfied, than the one-dimensional amount of information one-dimensional information amount has a relay optical system having the objective optical system And the one-dimensional information amount of the relay optical system is wasted,
An optical system having resolution and contrast that can support HDTV and the like cannot be obtained.

As described above, the rigid endoscope optical system of the present invention has the observation optical system having the above-described configuration, and the objective optical system and all the partial relay optical systems of the observation optical system are the same as those described above. It is characterized by satisfying the conditions (1) and (2).

In such a rigid mirror optical system of the present invention, it is preferable that the number of partial relay optical systems disposed in the insertion portion is two or less in order to reduce the amount of aberration generated in the entire relay optical system.

Most of the aberration of the rigid mirror optical system depends on the objective optical system and the relay optical system arranged in a narrow space in the insertion section. In an optical system configured to form a large number of intermediate images under the narrow spatial constraints in the insertion section, aberration correction is not easy. On the other hand, in an optical system arranged in a holding unit with less spatial restriction, aberration correction is relatively easy.

When the objective optical system and the relay optical system are compared, the relay optical system that performs image transmission a plurality of times is usually
The influence on the aberration of the entire optical system is large. Further, as described above, a relay optical system having an information amount satisfying the HDTV specification is an optical system with strict specifications for aberration correction.

The aberration of the relay optical system depends on the aberration of the partial relay optical system and the number of the partial relay optical systems.
As described above, it is impossible to completely correct the aberration of the partial relay optical system in the insertion portion having a large space constraint, and it is particularly difficult to correct the field curvature. This field curvature is almost determined by the number of partial relay optical systems.

For the above reasons, it is desirable that the number of partial relay optical systems be small in order to reduce residual aberration of the relay optical system, particularly field curvature, as much as possible. Therefore, it is desirable that the number of partial relay optical systems in the insertion portion is two or less.

If the number of partial relay optical systems is three or more, the aberration of the relay optical system, particularly the curvature of field becomes so large that the image quality around the visual field deteriorates, and the image quality of the HDTV camera cannot be utilized. Not preferred.

Another configuration of the rigid endoscope optical system according to the present invention is to perform observation with an erect image by adding an eyepiece optical system to the above basic configuration. In order to reduce the number, the number of partial relay optical systems in the relay optical system is limited to one. That is, in the optical system of the rigid endoscope including the insertion portion and the grip portion, as shown in FIG. 9, the observation optical system includes the objective optical system 3, the relay optical system 4, and the eyepiece optical system 6, and the relay optical system includes The objective optical system 3 and one partial relay optical system are arranged in the insertion portion 1 and at least the eyepiece optical system is arranged in the grip portion. (2) is satisfied.

Further, in the rigid mirror optical system having the above configuration, it is more preferable that the partial relay optical system arranged in the insertion portion satisfies the following condition (1-1) instead of the condition (1).

(1-1) 0.4 mm ≦ D _r ² / L _r ≦ 0.6 mm In the condition (1-1), the upper limit in the condition (1) is set to 0.6 mm instead of 0.8 mm. Things. Since there is no freedom of D _r If the outer diameter of the insertion portion is determined,
When the partial relay optical system is one, to the D _r ² / L _r to large must the L _r to small. However, if _Lr is reduced to exceed the upper limit of 0.6 mm of the condition (1-1), the effective length of the insertion portion required for the endoscopic surgery cannot be secured.

Still another configuration of the rigid mirror optical system of the present invention is as follows.
As shown in FIG. 10, the observation optical system of the basic configuration is configured by adding an eyepiece optical system, and a partial relay optical system (4-1, 4-
The number of 2) is set to 2, and the image inversion relay optical system 12 is arranged between the relay optical system 4 and the eyepiece optical system 6 to enable bright upright image observation. Further, an objective optical system and a relay optical system (two partial relay optical systems) are arranged in the insertion section 1, and an eyepiece optical system and an image inverting relay optical system are arranged in the holding section.

The brightness of the HDTV camera varies, and depending on the TV camera used, the brightness may be a problem. Therefore, when the relay optical system is composed of only one partial optical system, even if a sufficiently good image quality is obtained, the brightness may be insufficient in some cases, and it is necessary to increase the number of relays. However, if three partial relay optical systems are arranged in the insertion section to form an erect image and to make the image brighter, it becomes difficult to satisfactorily correct aberrations.

For this purpose, two partial relay optical systems are arranged in the insertion portion, and an image inverting relay optical system is arranged in the grip portion to make the image upright by performing image transmission once in the grip portion. It was made to be able to observe with an erect image. By arranging the image reversing relay optical system in the holding section in this manner, aberration correction becomes relatively easy, and it is possible to design the optical system almost without aberration.

As means for inverting the image, an optical system using a prism such as a Porro prism may be arranged instead of the image inversion relay optical system. in this case,
It is necessary to arrange a prism between the relay optical system and the eyepiece optical system, and a prism such as a Porro prism needs a very long front focal length of the eyepiece optical system due to a long glass path. Design becomes practically difficult. Therefore, it is not practically preferable to use a prism optical system as the image inversion optical system.

The rigid mirror optical system of the present invention having the arrangement of the image inversion relay optical system also needs to satisfy the conditions (1) and (2). However, the following condition (1) is used instead of the condition (1). −
It is more preferable to satisfy 2).

(1-2) 0.5 mm ≦ D _r ² / L _r ≦ 0.7 mm In the condition (1-2), the upper limit and the lower limit of the condition (1) were changed to narrow the range. Things.

In the rigid endoscope optical system having the above configuration, the brightness of the optical system is increased. However, if the value falls below the lower limit of 0.5 mm of the condition (1-2), the brightness may be reduced depending on clinical conditions. Becomes insufficient. If the value exceeds the upper limit of 0.7 mm, it becomes difficult to correct aberrations. To satisfactorily correct aberrations other than distortion, special measures such as using an aspherical surface in the relay optical system or objective optical system are required. Become.

Next, in the rigid mirror optical system of the present invention, the partial relay optical system of the relay optical system is composed of first, second, and third lens components in order from the object side, and the first lens The component has a biconvex shape with a center thickness greater than the outer diameter,
The lens having the largest medium thickness of the lens component has a refractive index of 1.65 or more, the second lens component has a biconvex shape,
It is desirable that the third lens component has the same shape as the first lens component, and that the third lens component has a symmetrical arrangement in the entire partial relay optical system constituted by these lens components.

By configuring the partial relay optical system as described above, aberration can be reduced while increasing the numerical aperture.
Further, the number of surfaces in contact with air can be relatively reduced.

In order to perform the aberration correction necessary to satisfy the specifications of the optical system of the present invention, for example, the following first embodiment will be described.
As in FIG. 1, the partial relay optics must have positive power and have at least six surfaces in contact with air. Of these six surfaces, two surfaces are near image positions on both sides of the partial relay optical system and contribute to pupil transmission. The remaining four surfaces are intermediate surfaces of the partial relay optical system and contribute to image transmission. If there are no more than four surfaces in contact with air of positive power that contribute to image transmission in the intermediate portion, spherical aberration will be curved on the aberration diagram, and sufficient contrast cannot be obtained even at the center of the field of view. On the other hand, in order to reduce the occurrence of flare due to the surface reflection of the lens, the number of surfaces in contact with air is preferably as small as possible.

For the above reasons, it is desirable that the partial relay optical system of the optical system according to the present invention is constituted by three lens components including the first, second, and third lens components. With such a configuration, there is no surface in contact with air other than the six surfaces in contact with air, which are necessary for correcting spherical aberration. An increase in flare light can be prevented.

Further, in consideration of correction of coma and chromatic aberration of magnification, it is desirable that the partial relay optical system has an equal magnification and a symmetrical configuration. If the partial relay optical system is made symmetrical, the two lens units located on the image side
The directions are different with the same shape.

The first lens component and the third lens component located on the image side are preferably formed of a medium having a large medium thickness and a high refractive index in order to increase the numerical aperture. Therefore, the first and third lens components on the image side are formed in a rod shape having a medium thickness larger than the outer diameter, and the refractive index of the thickest lens among the lenses constituting the lens component is set to the above-mentioned value. If it is 1.65 or more, a required numerical aperture can be obtained. If the refractive index of this thickest lens is less than 1.65, the required numerical aperture cannot be obtained.

Next, in the hard mirror optical system of the present invention, a direction different from the optical axis direction of the optical system, such as for oblique viewing, can be observed by disposing a viewing direction conversion prism at the tip of the objective optical system. An optical system for imaging can be provided.

For example, as shown in FIG. 11, a first lens unit having negative power is arranged in order from the object side of the objective optical system.
This is a configuration including a viewing direction conversion prism and a second lens group having a positive power. It is desirable that the objective optical system having this configuration satisfies the following condition (3).

(3) 0.2 ≦ T _p / L _o ≦ 0.4 Rigid endoscopes used in endoscopic surgery have various viewing directions and are provided with the viewing direction changing prism as described above. An optical system capable of observing and photographing in various viewing directions is required. In particular, there is a strong demand for a rigid endoscope having a viewing direction of 25 ° to 45 °.

The optical system according to the present invention having the above-mentioned basic structure is
Since the product of the numerical aperture and the size of the image is very large, the pupil in the objective optical system becomes very large. For this reason, a viewing direction changing prism used in the rigid hard mirror for perspective needs to be able to pass a light beam having a large diameter. 25 ° to 45 °
A viewing direction conversion prism having a viewing direction conversion angle of ° and capable of passing a light beam having a large diameter requires an extremely long glass path. In order to secure such a space for disposing the viewing direction conversion prism, the objective optical system is configured as described above, that is, in order from the object side, the negative first lens group, the viewing direction conversion prism, and the positive It is desirable that the second lens group be constituted. Further, the viewing direction changing prism is provided with the glass path T
_The ratio of _{p to} the total length of the objective optical system must be increased. Therefore, it is desirable that the condition (3) is satisfied.

In the above condition (3), when T _p / L _o exceeds the lower limit of 0.2, the viscous path of the prism becomes insufficient, and a viewing direction changing prism capable of passing a light beam having a very large diameter is constructed. I cannot do it. In addition, T _p / _Lo is the upper limit of 0.
If it exceeds 4, the distance from the first lens group is too large, the diameter of the light beam in the second lens group becomes large, and the effective light beam is emitted by the second lens group.

As described above, the basic configuration of the optical system according to the present invention is configured by the objective optical system and the relay optical system including one or a plurality of partial relay optical systems in the insertion portion of the rigid endoscope. , Conditions (1) and (2) are satisfied.

In the present invention, when the relay optical system is composed of a plurality of partial relay optical systems, it is conceivable that a part of the partial relay optical system is arranged in the holding portion. In this case, the partial relay optical system in the gripping part also satisfies the condition (1),
It is desirable to satisfy (2).

[0074]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the rigid mirror optical system according to the present invention will be described based on the optical systems of the respective embodiments.

Each embodiment of the optical system of the present invention has the following data. Example 1 Object distance = 60.0000, Image height = 3.500, Focal length = 4.368, F-number = 3.766 Full length (first surface to last surface) = 353.800, Angle of view = 80 °, Exit pupil position = ∞ r ₁ = ∞ d ₁ = 0.7000 n ₁ = 1.76820 ν ₁ = 71.79 r ₂ = ｄ d ₂ = 0.3500 r ₃ = ∞ d ₃ = 0.5000 n ₂ = 1.84772 ν ₂ = 25.76 r ₄ = 3.2719 (aspherical surface) d ₄ = 1.6000 r ₅ = _{∞ d 5 = 19.2388 n 3 =} 1.88300 ν 3 = 40.78 r 6 = ∞ ( _{stop) d 6 = 2.3312 n 4 =} 1.88300 ν 4 = 40.78 r 7 = ∞ d 7 = 2.0000 n 5 = 1.48749 ν 5 = 70.21 r 8 _{= 10.4840 d 8 = 1.2900 r 9} = 21.0720 d 9 = 5.9300 n 6 = 1.80440 ν 6 = 39.58 r 10 = -23.7790 d 10 = 0.5000 r 11 = 28.9610 d 11 = 7.4500 n 7 = 1.72916 ν 7 = 54.68 r 12 = _{-22.5740 d 12 = 0.5000 r 13 =} 16.9530 d 13 = 4.2300 n 8 = 1.77250 ν 8 = 49.60 r 14 = 79.4570 d 14 = 1.5000 n 9 = 1.84666 ν 9 = 23.78 r 15 = 8.1920 d 15 = 4.3100 r 16 = 11.0310 _{16 = 2.9100 n 10 = 1.77250 ν} 10 = 49.60 r 17 = 79.4570 d 17 = 1.5000 n 11 = 1.84666 ν 11 = 23.78 r 18 = 6.4000 d 18 = 1.9900 r 19 = 12.3610 d 19 = 8.5200 n 12 = 1.81600 ν 12 = _{46.62 r 20 = -5.2300 d 20 =} 1.5000 n 13 = 1.84666 ν 13 = 23.78 r 21 = -24.0550 d 21 = 4.9900 r 22 = ∞ ( _{image) d 22 = 5.0300 r 23 =} 27.9810 d 23 = 3.9600 n 14 = 1.69680 ν ₁₄ = 55.53 r ₂₄ = ∞ d ₂₄ = 42.0400 n ₁₅ = 1.72916 ν ₁₅ = 54.68 r ₂₅ = ∞ d ₂₅ = 6.6600 n ₁₆ = 1.58313 ν ₁₆ = 59.38 r ₂₆ = -10.5000 d ₂₆ = 1.5000 n ₁₇ = 1.88300 ν ₁₇ = 40.78 r ₂₇ = -25.5920 d ₂₇ = 0.8000 r ₂₈ = 27.6560 d ₂₈ = 10.0000 n ₁₈ = 1.51742 ν ₁₈ = 52.42 r ₂₉ = ｄ d ₂₉ = 10.0000 n ₁₉ = 1.51742 ν ₁₉ = 52.42 r ₃₀ = -27.6560 d _{30 = 0.8000 r 31 = 25.5920 d} 31 = 1.5000 n 20 = 1.88300 ν 20 = 40.78 r 32 = 10.5000 d 32 = 6.6600 n 21 = 1.58313 ν 21 = 59.38 r 33 = ∞ d 33 = 42.040 0 n ₂₂ = 1.72916 v ₂₂ = 54.68 r ₃₄ = ∞ d ₃₄ = 3.9600 n ₂₃ = 1.69680 v ₂₃ = 55.53 r ₃₅ = -27.9810 d ₃₅ = 5.0300 r ₃₆ = ∞ (image) d ₃₆ = 5.0300 r ₃₇ = 27.9810 d ₃₇ = 3.9600 n ₂₄ = 1.69680 v ₂₄ = 55.53 r ₃₈ = ∞ d ₃₈ = 42.0400 n ₂₅ = 1.72916 v ₂₅ = 54.68 r ₃₉ = ∞ d ₃₉ = 6.6600 n ₂₆ = 1.58313 v ₂₆ = 59.38 r ₄₀ = -10.5000 d _{40 = 1.5000 n 27 = 1.88300 ν 27} = 40.78 r 41 = -25.5920 d 41 = 0.8000 r 42 = 27.6560 d 42 = 10.0000 n 28 = 1.51742 ν 28 = 52.42 r 43 = ∞ d 43 = 10.0000 n 29 = 1.51742 ν 29 = _{52.42 r 44 = -27.6560 d 44 =} 0.8000 r 45 = 25.5920 d 45 = 1.5000 n 30 = 1.88300 ν 30 = 40.78 r 46 = 10.5000 d 46 = 6.6600 n 31 = 1.58313 ν 31 = 59.38 r 47 = ∞ d 47 = 42.0400 n ₃₂ = 1.72916 v ₃₂ = 54.68 r ₄₈ = ∞ d ₄₈ = 3.9600 n ₃₃ = 1.69680 v ₃₃ = 55.53 r ₄₉ = -27.9810 d ₄₉ = 5.0300 r ₅₀ = ∞ (image) Aspheric coefficient K = -1.0677 ^{, E = 2.4683 × 10 -4,} F = -6.3235 × 10 -5, G = 3.2907 × 10 -6 ( objective optical _{system) L o = 73.84 mm, D} o = 9.5mm, D o 2 / L o = 1.22 mm, T _p = 21.57 mm T _p / L _o = 0.292 Focal length f ₁ of the first lens group = 4.170 mm Focal length f ₂ of the second lens group = 18.056 mm (relay optical system) First partial relay optics system _{L r = 139.98mm, D r =} 9.5mm, D r 2 / L r = 0.65mm second portion relay optical system _{L r = 139.98mm, D r =} 9.5mm, D r 2 / L r = 0.65mm

Embodiment 2 Object distance = 70.0000, Image height = 3.500, Focal length = 6.022, F number = 4.163 Full length (first surface to last surface) = 353.800, Field angle = 70 °, Exit pupil position = 位置 r ₁ = ∞ d ₁ = 0.7000 n ₁ = 1.76820 v ₁ = 71.70 r ₂ = ∞ d ₂ = 0.3500 r ₃ = ∞ d ₃ = 0.5000 n ₂ = 1.88300 v ₂ = 40.78 r ₄ = 5.1680 d ₄ = 1.6000 r ₅ = ∞ _{d 5 = 20.6621 n 3 = 1.88300} ν 3 = 40.78 r 6 = ∞ d 6 = 0.9079 n 4 = 1.88300 ν 4 = 40.78 r 7 = ∞ d 7 = 2.0000 n 5 = 1.84666 ν 5 = 23.78 r 8 = 13.4680 d 8 = 2.3000 r ₉ = -21.0720 d ₉ = 2.0000 n ₆ = 1.59270 v ₆ = 35.30 r ₁₀ = 26.2580 d ₁₀ = 3.0000 n ₇ = 1.77250 v ₇ = 49.60 r ₁₁ = -13.4990 d ₁₁ = 0.3000 r ₁₂ = 61.8010 d ₁₂ = 4.0000 n ₈ = 1.81600 v ₈ = 46.62 r ₁₃ = -21.4790 d ₁₃ = 0.3000 r ₁₄ = 11.8860 d ₁₄ = 4.9000 n ₉ = 1.81600 v ₉ = 46.62 r ₁₅ = -143.9420 d ₁₅ = 2.3300 r ₁₆ = -22.7570 d ₁₆ = 2.0000 n ₁₀ = 1.84666 v ₁₀ = 23.78 r ₁₇ = 5.4960 d ₁₇ = 3.1500 r ₁₈ = -58.6910 d ₁₈ = 3.5000 n ₁₁ = 1.88 300 v ₁₁ = 40.78 r ₁₉ = -5.4520 d ₁₉ = 2.0000 n ₁₂ = 1.54814 v _{12 = 45.78 r 20 = 13.1870 d 20} = 4.3800 r 21 = 31.7660 d 21 = 5.9700 n 13 = 1.88300 ν 13 = 40.78 r 22 = -5.6040 d 22 = 2.0000 n 14 = 1.84666 ν 14 = 23.78 r 23 = -49.9910 d 23 = 4.9900 r ₂₄ = ∞ (image) d ₂₄ = 5.0300 r ₂₅ = 27.9810 d ₂₅ = 3.9600 n ₁₅ = 1.69680 v ₁₅ = 55.53 r ₂₆ = ∞ d ₂₆ = 42.0400 n ₁₆ = 1.72916 v ₁₆ = 54.68 r ₂₇ = ₂₇ d ₂₇ = 6.6600 n ₁₇ = 1.58313 ν ₁₇ = 59.38 r ₂₈ = -10.5000 d ₂₈ = 1.5000 n ₁₈ = 1.88 300 ν ₁₈ = 40.78 r ₂₉ = -25.5920 d ₂₉ = 0.8000 r ₃₀ = 27.6560 d ₃₀ = 10.0000 n ₁₉ = 1.51742 ν _{19 = 52.42 r 31 = ∞ d} 31 = 10.0000 n 20 = 1.51742 ν 20 = 52.42 r 32 = -27.6560 d 32 = 0.8000 r 33 = 25.5920 d 33 = 1.5000 n 21 = 1.88300 ν 21 = 40.7 8 r ₃₄ = 10.5000 d ₃₄ = 6.6600 n ₂₂ = 1.58313 ν ₂₂ = 59.38 r ₃₅ = ｄ d ₃₅ = 42.0400 n ₂₃ = 1.72916 ν ₂₃ = 54.68 r ₃₆ = ｄ d ₃₆ = 3.9600 n ₂₄ = 1.96880 ν ₂₄ = 55.53 r ₃₇ = -27.9810 d ₃₇ = 5.0300 r ₃₈ = ∞ (image) d ₃₈ = 5.0300 r ₃₉ = 27.9810 d ₃₉ = 3.9600 n ₂₅ = 1.69680 ν ₂₅ = 55.53 r ₄₀ = ∞ d ₄₀ = 42.0400 n ₂₆ = 1.72916 ν ₂₆ = 54.68 r ₄₁ = ∞ d ₄₁ = 6.6600 n ₂₇ = 1.58313 v ₂₇ = 59.38 r ₄₂ = -10.5000 d ₄₂ = 1.5000 n ₂₈ = 1.88 300 v ₂₈ = 40.78 r ₄₃ = -25.5920 d ₄₃ = 0.8000 r ₄₄ = 27.6560 d ₄₄ = 10.0000 n ₂₉ = 1.51742 v ₂₉ = 52.42 r ₄₅ = ∞ d ₄₅ = 10.0000 n ₃₀ = 1.51742 v ₃₀ = 52.42 r ₄₆ = -27.6560 d ₄₆ = 0.8000 r ₄₇ = 25.5920 d ₄₇ = 1.5000 n ₃₁ = 1.88 300 v ₃₁ = 40.78 r ₄₈ = 10.5000 d ₄₈ = 6.6600 n ₃₂ = 1.58313 ν ₃₂ = 59.38 r ₄₉ = ∞ d ₄₉ = 42.0400 n ₃₃ = 1.72916 ν ₃₃ = 54.68 r ₅₀ = ｄ d ₅₀ = 3.9600 n ₃₄ = 1.96880 ν _{34 = 55.53 r 51 = -27.9810 d} 51 = 5.0300 r 52 = ∞ ( image) (objective optical _{system) L o = 73.84 mm, D} o = 9.5mm, D o 2 / L o = 1.22mm, T p = 21.57 mm T _p / L _o = 0.292 Focal length f ₁ of the first lens group f − = 5.853 mm Focal length f ₂ of the second lens group = 18.784 mm (relay optical system) First partial relay optical system L _r = 139.98 mm _{, D r = 9.5mm, D r} 2 / L r = 0.65mm second portion relay optical system _{L r = 139.98mm, D r =} 9.5mm, D r 2 / L r = 0.65mm

Embodiment 3 Object distance = 60.0000, Image height = 3.500, Focal length = -4.357, F number = 5.657 Full length (first surface to final surface) = 282.774, Field angle = 80 °, Exit pupil position = ∞ r ₁ = ∞ d ₁ = 0.7000 n ₁ = 1.76820 v ₁ = 71.79 r ₂ = ∞ d ₂ = 0.3500 r ₃ = ∞ d ₃ = 0.5000 n ₂ = 1.78472 v ₂ = 25.76 r ₄ = 3.2000 (aspherical surface) d ₄ = _{1.6000 r 5 = ∞ d 5 =} 20.5700 n 3 = 1.88300 ν 3 = 40.78 r 6 = ∞ d 6 = 1.0000 n 4 = 1.88300 ν 4 = 40.78 r 7 = ∞ d 7 = 4.0000 n 5 = 1.69895 ν 5 = 30.12 r _{8 = -19.4047 d 8 = 0.5000 r} 9 = 7.9827 d 9 = 5.5000 n 6 = 1.58913 ν 6 = 61.18 r 10 = -6.5645 d 10 = 2.0000 n 7 = 1.80610 ν 7 = 40.95 r 11 = -33.2181 d 11 = 0.5000 _{r 12 = 11.8166 d 12 = 2.5000} n 8 = 1.72916 ν 8 = 54.68 r 13 = 5.5779 d 13 = 3.0538 r 14 = 22.5895 d 14 = 5.0000 n 9 = 1.51633 ν 9 = 64.15 r 15 = -5.2217 d 15 = 1.5000 n ₁₀ = 1.846 66 ν ₁₀ = 23.78 r ₁₆ = -15.8267 d ₁₆ = 1.0000 r ₁₇ = 17.0907 d ₁₇ = 6.0000 n ₁₁ = 1.77250 ν ₁₁ = 49.60 r ₁₈ = -5.3000 d ₁₈ = 1.5000 n ₁₂ = 1.78472 ν ₁₂ = 25.68 r ₁₉ = _{-50.0000 d 19 = 5.0000 r 20 =} ∞ ( _{image) d 20 = 5.0000 r 21 =} 33.6801 d 21 = 4.0000 n 13 = 1.51633 ν 13 = 64.15 r 22 = ∞ d 22 = 74.8419 n 14 = 1.77250 ν 14 = 49.60 r _{23 = ∞ d 23 = 5.0000 n} 15 = 1.51633 ν 15 = 64.15 r 24 = -16.7975 d 24 = 1.5000 n 16 = 1.88300 ν 16 = 40.78 r 25 = -32.6303 d 25 = 1.0000 r 26 = 44.2288 d 26 = 37.3163 n ₁₇ = 1.53172 ν ₁₇ = 48.91 r ₂₇ = -44.2288 d ₂₇ = 1.0000 r ₂₈ = 32.6303 d ₂₈ = 1.5000 n ₁₈ = 1.88300 ν ₁₈ = 40.78 r ₂₉ = 16.7975 d ₂₉ = 5.0000 n ₁₉ = 1.51633 ν ₁₉ = 64.15 r ₃₀ = ∞ d ₃₀ = 74.8419 n ₂₀ = 1.77250 ν ₂₀ = 49.60 r ₃₁ = ∞ d ₃₁ = 4.0000 n ₂₁ = 1.51633 ν ₂₁ = 64.15 r ₃₂ = -33.6801 d ₃₂ = 5.0000 r ₃₃ = ∞ (image) Surface coefficient K = -1.1736, E = 0, F = 0, G = 0 ( objective optical _{system) L o = 62.77 mm, D} o = 9.5mm, D o 2 / L o = 1.44mm, T p = 21.57mm T _p / L _o = 0.344 focal distance f ₂ = 17.301mm (relay optical system) of the focal length f ₁ = -4.078mm second lens group of the first lens group moiety relay optical system L _r = 220.00mm, D _r = ^{_{9.5mm, D r 2 / L r}} = 0.41mm

Example 4 Object Distance = 0, Object Height = 3,500, Focal Length = 28.478, Object-side NA = −0.1405 Overall Length (First Surface to Last Surface) = 44.790, Entrance Pupil Position = ∞ r ₁ = ∞ (Image D ₁ = 8.4000 r ₂ = ∞ d ₂ = 4.0000 n ₁ = 1.72916 v ₁ = 54.68 r ₃ = -21.2750 d ₃ = 0.3000 r ₄ = 20.5810 d ₄ = 4.7100 n ₂ = 1.72916 v ₂ = 54.68 r ₅ = ₅ d ₅ = 2.5000 n ₃ = 1.51633 ν ₃ = 64.15 r ₆ = 11.8670 d ₆ = 3.8800 r ₇ = −7.0240 d ₇ = 2.5000 n ₄ = 1.76182 v ₄ = 26.52 r ₈ = ∞ d ₈ = 5.7000 n ₅ = 1.72916 ν _{5 = 54.68 r 9 = -11.8860 d} 9 = 0.3000 r 10 = ∞ d 10 = 3.5000 n 6 = 1.77250 ν 6 = 49.60 r 11 = -28.7500 d 11 = 6.0000 r 12 = ∞ d 12 = 3.0000 n 7 = 1.76820 ν ₇ = 71.70 r ₁₃ = ∞

Example 5 Object distance = 0.000, image height = 3.500, focal length = 92.152, F number = 3.539 Object side NA = 0.1413, image side NA = -0.1413 Total length (first surface to final surface) = 70.000, incidence Pupil position = ∞, exit pupil position = ∞ r ₁ = ∞ (image) d ₁ = 5.0000 r ₂ = 55.6570 d ₂ = 4.5000 n ₁ = 1.83481 ν ₁ = 42.72 r ₃ = -16.5080 d ₃ = 3.1800 r ₄ = 18.9300 d ₄ = 3.0000 n ₂ = 1.58144 ν ₂ = 40.77 r ₅ = 7.2040 d ₅ = 7.8300 r ₆ = -7.2040 d ₆ = 2.5000 n ₃ = 1.72825 v ₃ = 28.46 r ₇ = ∞ d ₇ = 4.7900 n ₄ = 1.72916 ν _{4 = 54.68 r 8 = -11.9640 d} 8 = 0.5000 r 9 = ∞ d 9 = 3.2000 n 5 = 1.72916 ν 5 = 54.68 r 10 = -22.7570 d 10 = 0.5000 r 11 = ∞ ( stop) d ₁₁ = 0.5000 r _{12 = 22.7570 d 12 = 3.2000 n 6} = 1.72916 ν 6 = 54.68 r 13 = ∞ d 13 = 0.5000 r 14 = 11.9640 d 14 = 4.7900 n 7 = 1.72916 ν 7 = 54.68 r 15 = ∞ d 15 = 2.5000 n 8 = 1.7282 5 ν ₈ = 28.46 r ₁₆ = 7.2040 d ₁₆ = 7.8300 r ₁₇ = −7.2040 d ₁₇ = 3.0000 n ₉ = 1.58144 ν ₉ = 40.77 r ₁₈ = -18.9300 d ₁₈ = 3.1800 r ₁₉ = 16.5080 d ₁₉ = 4.5000 n ₁₀ = 1.83481 ν ₁₀ = 42.72 r ₂₀ = -55.6570 d ₂₀ = 5.0000 r ₂₁ = ∞ (image) where r ₁ , r ₂ ,... Are the radii of curvature of the respective surfaces of the lens, d
_.. , D ₂ ,...
₁ , n ₂ ,... Are the refractive indices of each lens, ν ₁ , ν ₂ ,.
Is the Abbe number of each lens.

The first embodiment has a configuration as shown in FIG.
(A) is an objective optical system, and (B) is a partial relay optical system of a relay optical system.

In the data, r ₁ to r _{22 correspond} to r by the objective optical system.
_{1 to} r ₄ are the first lens groups r _{7 to} r ₂₂ are the second lens groups, r
₂₂ ~r ₅₀ is a relay optical system, r ₂₂ ~r ₃₆ of the relay optical system is first partial relay optical system, the r ₃₆ ~r ₅₀ is a second partial relay optical system, r _22, r ₃₆ and r ₅₀ are image positions, and the final image of the relay optical system is an inverted image.

Also, r ₆ indicates a virtual stop position, and therefore r _{5 to} r ₇ are block-shaped optical elements, and n ₃ and v ₃ and n ₄ and v ₄ indicate the material of this one optical element. It is divided into two for the description of the data.

Although FIG. 1B shows only the first partial optical system, the second partial optical system has the same configuration as the first partial optical system.

The optical system of the first embodiment satisfies the condition (1),
Satisfies (2). The objective optical system is provided with a flat凹非spherical lens (r ₃ ~r ₄₎ in order to correct distortion.
The distance from the fifth surface r ₅ to seventh surface r ₇ is a large,
The thick block-shaped portion here may be used as a viewing direction changing prism to constitute a rigid microscope for perspective use.

In the relay optical system, the partial relay optical system has a biconvex first lens component having a large center thickness, a biconvex second lens component, and a third lens component having the same configuration as the first lens component.
It consists of a lens component and is arranged symmetrically as a whole.

The state of aberration in this embodiment is as shown in FIG.

In the second embodiment, the objective optical system is as shown in FIG. 2, and the relay optical system uses the same optical system as in the first embodiment. That r ₁ ~r ₄ is the first lens group in r ₁ ~r ₂₄ is the objective optical system in data, r ₇ ~r ₂₄ is a second lens group, r ₂₄ ~r ₅₂ is r ₂₄ ~ in the relay optical system
r ₃₈ is the first portion relay optical system, r ₃₈ ~r ₅₂ is a second partial relay optical system is the same as the relay optical system of Example 1. Also, r ₂₄ , r ₃₈ and r ₅₂ are image positions, and the final image is an inverted image.

Further, r ₆ indicates a virtual stop position, and therefore r _{5 to} r ₇ are block-shaped optical elements, and n ₃ and v ₃ and n ₄ and v ₄ indicate the material of this one optical element. It is divided into two for the description of the data.

The optical system according to the second embodiment also has the conditions (1) and (2).
(2) I am satisfied. The objective optical system consists of only spherical lenses, the fifth surface r ₅ the spacing seventh surface r ₇ A large, can also be in the visual field direction changing prism can be a perspective for rigid endoscope.

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

Embodiment 3 is as shown in FIG. 3, in which (A) is an objective optical system, (B) is a partial relay optical system of a relay optical system, and is composed of one partial relay optical system.

The final image of the relay optical system of this embodiment is an erect image. Also, r ₆ indicates a virtual stop position, and therefore r _{5 to} r ₇ are block-like optical elements, n ₃ and ν ₃ and n ₄ and ν ₄ indicate the material of this one optical element, and the data is described. The upper two are shown separately.

The optical system according to this embodiment has the following conditions (1)
Satisfies (2). The objective optical system uses a plano-concave aspheric lens for correcting distortion. The relay optical system (partial relay optical system) includes a biconvex first lens component having a large center thickness, a biconvex second lens component, and a third lens component identical to the first lens component. Are arranged symmetrically. The interval between the fifth surface r ₅ ~ seventh surface r ₇ is large, it can be a field direction changing prism.

The aberration situation in the third embodiment is as shown in FIG.

The shapes of the aspherical surfaces in the first and third embodiments are represented by the following formulas when the optical axis direction is Z and the direction perpendicular to the optical axis is Y.

Where R is the radius of curvature of the reference sphere, K,
E, F, G,... Are aspherical coefficients.

The fourth embodiment is an eyepiece optical system which is assumed to be used in combination with the optical systems of the first to third embodiments, and has a configuration as shown in FIG. The eyepiece optical system is arranged after the relay optical system as shown in FIG. 9, and the rigid mirror optical system has an objective optical system, a relay optical system, and an eyepiece optical system arranged in this order from the object side as a whole.

When the eyepiece optical system shown in FIG. 4 is used in combination with the first or second embodiment, an inverted image is observed. You will observe a standing image.

The eyepiece optical system used in the rigid mirror optical system of the present invention has a high specification and requires strict aberration correction. However, since the eyepiece optical system is arranged in the grip, it is possible to design an optical system having high spatial flexibility and good optical performance.

The eyepiece optical system according to the fourth embodiment is a high-grade Gaussian type optical system as an eyepiece optical system for a rigid endoscope.

In the data, r ₁ is the final image plane of the relay optical system, and the plane-parallel plates r _{12 to} r ₁₃ are coverlass.

Embodiment 5 shown in FIG. 5 is an image inversion relay optical system used in the rigid mirror optical system of the present invention, and is designed on the assumption that it is used in combination with Embodiment 1 or Embodiment 2. Things. When the image inversion relay optical system of this embodiment is used in combination with the first or second embodiment, as shown in FIG. 10, the objective optical system 3, the relay optical system 4, the image inversion optical system 12, and the eyepiece optics from the object side. They are arranged in the order of the system 16. Thus, the inverted image formed by the relay optical system becomes an erect image by the image inverting optical system, and this erect image is observed by the eyepiece optical system.

When this image reversing optical system is also used in the rigid mirror optical system of the present invention, its specifications are high and strict aberration correction is required. In a normal relay optical system, it is necessary to satisfactorily correct field curvature that tends to remain. However, since this image reversing relay optical system can be arranged in the grip portion, spatial restriction is small and flexibility is high, so that good aberration correction can be performed.

Since the image inversion relay optical system of the fifth embodiment has a configuration in which two modified Gaussian type optical systems are arranged symmetrically, all aberrations including field curvature are corrected well. I have. In this image reversing relay optical system, it is desirable to arrange a brightness stop including a role of flare reduction at a pupil position at the center thereof.

The eyepiece optical system according to the fourth embodiment can be used.

FIG. 11 shows a viewing direction changing prism used in the rigid mirror optical system of the present invention.
(B) is a perspective view. This corresponds to Example 1 of the present invention,
It can be used for a few optical systems. These Examples 1,
Instead of the block-shaped portions of the third to seventh surfaces in the few objective optical systems, a perspective objective optical system can be configured using a viewing direction conversion prism shown in FIG. By using the viewing direction conversion prism shown in this figure, the viewing direction can be inclined by 35 ° with respect to the optical axis of the relay optical system.

The viewing direction changing prism includes, in order from the object side, an incident surface R ₁ perpendicular to the object-side optical axis, a first reflecting surface R ₂ parallel to the optical axis of the relay optical system, and a first reflecting surface R 1. The half angle (17.5) of the viewing direction conversion angle (35 °) with respect to ₂
°) it has become more and the second reflecting surface R ₃ perpendicular exit surface R ₄ in the relay optical system is inclined by. The first reflection surface R ₂ and the second reflection surface R ₃ both use total reflection. Further, it is desirable to use a material having a high refractive index (1.883) for the prism in order to secure a margin of the critical angle. The glass path length T _p between the entrance surface R ₁ and the exit surface R ₄ of the viewing direction conversion prism is 21.57 mm, and when applied to the objective optical systems of Examples 1, 2, and 3, all conditions are satisfied. It is configured to satisfy (3).

In the present invention, in addition to the optical system described in the claims, an optical system having the following configuration can also achieve the object of the present invention.

(1) Claims 1, 2, and 3 of the claims
Or the rigid mirror optical system according to 4, wherein the partial relay optical system is composed of a first lens component, a second lens component, and a third lens component in order from the object side, and the first lens component has a center thickness greater than an outer diameter. Is large, the second lens component has a biconvex shape, the third lens component has the same shape as the first lens component, and the entire partial relay optical system has a symmetric configuration. And a rigid endoscope optical system.

(2) The rigid mirror optical system according to claim 1, wherein the objective optical system includes, in order from the object side, a first lens group having a negative power; A rigid mirror optical system comprising a conversion prism and a second lens group having a positive power, and satisfying the following condition (3). (3) 0.2 ≦ T _p / L _o ≦ 0.4

(3) The rigid mirror optical system according to claim 3 or (1) or (2), wherein the following condition (1-1) is satisfied instead of condition (1). A rigid mirror optical system characterized by satisfying. ^{_{(1-1) 0.4mm ≦ D r 2}} / L r ≦ 0.6mm

(4) The rigid mirror optical system according to claim 4 or (1) or (2), wherein the following condition (1-2) is used instead of condition (1). A rigid mirror optical system characterized by satisfying. ^{_{(1-2) 0.5mm ≦ D r 2}} / L r ≦ 0.7mm

[0113]

According to the present invention, it is possible to realize a rigid-mirror optical system having a resolution equal to or higher than that of an HDTV and having an information amount compatible with an HDTV camera.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of a rigid mirror optical system according to the present invention.

FIG. 2 is a diagram showing a configuration of an objective optical system according to a second embodiment of the rigid mirror optical system of the present invention;

FIG. 3 is a diagram showing a configuration of a hard mirror optical system according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of an eyepiece optical system of a rigid endoscope optical system according to the present invention.

FIG. 5 is a diagram showing a configuration of an image inversion relay optical system of the rigid mirror optical system of the present invention.

FIG. 6 is an aberration curve diagram according to the first embodiment of the present invention.

FIG. 7 is an aberration curve diagram according to the second embodiment of the present invention.

FIG. 8 is an aberration curve diagram according to the third embodiment of the present invention.

FIG. 9 is a schematic diagram showing an example of the entire configuration of a rigid mirror optical system according to the present invention.

FIG. 10 is a schematic diagram showing another example of the entire configuration of the rigid mirror optical system of the present invention.

FIG. 11 is a diagram showing a configuration of a viewing direction conversion prism used in the rigid mirror optical system of the present invention.

FIG. 12 is a diagram showing a configuration of an observation optical system of the rigid endoscope system.

Claims (4)

[Claims] 1. An observation optical system disposed in an insertion section includes an objective optical system and a relay optical system in order from a distal end, and a relay optical system located in the insertion section is a single or a plurality of partial relay optical systems. Wherein the objective optical system and all of the partial relay optical systems satisfy the following conditions (1) and (2). ^{_{(1) 0.4mm ≦ D r 2}} / L r ≦ 0.8mm (2) D o 2 / L o ≧ D r 2 / L r However, D _o is the maximum lens diameter of the objective optical system (mm), L _o
Is the total length (mm) of the objective optical system, _Dr is the maximum lens outer diameter (mm) of the partial relay optical system, and _Lr is (m) of the partial relay optical system.
m) Total length. 2. The rigid mirror optical system according to claim 1, wherein the number of partial relay optical systems located in said insertion portion is two or less. 3. A rigid endoscope having an insertion portion and a grip portion, wherein the observation optical system in the insertion portion comprises an objective optical system and a relay optical system in order from the tip, and the observation optical system in the grip portion is an eyepiece optical system. Wherein the relay optical system located in the insertion portion comprises one partial relay optical system, and wherein the objective optical system and the partial relay optical system satisfy the following conditions: Optical system. ^{_{(1) 0.4mm ≦ D r 2}} / L r ≦ 0.8mm (2) D o 2 / L o ≧ D r 2 / L r However, D _o is the maximum lens diameter of the objective optical system (mm), L _o
The overall length of the objective optical system (mm), D _r partial maximum lens diameter of the relay optical system (mm), L _r is the total length of the portion relay optical system. 4. A rigid endoscope having an insertion portion and a grip portion, wherein the observation optical system in the insertion portion is composed of an objective optical system and a relay optical system in order from the distal end side, and the observation optical system in the grip portion is image-inverted. In a rigid mirror optical system including a relay optical system and an eyepiece optical system, the relay optical system located in the insertion portion includes two partial relay optical systems, and all of the objective optical system and the partial relay optical system satisfy the following conditions. A rigid mirror optical system characterized by satisfying the following. ^{_{(1) 0.4mm ≦ D r 2}} / L r ≦ 0.8mm (2) D o 2 / L o ≧ D r 2 / L r However, D _o is the maximum lens diameter of the objective optical system (mm), L _o
Is the total length (mm) of the objective optical system, _Dr is the maximum lens outer diameter (mm) of the partial relay optical system, and _Lr is (m) of the partial relay optical system.
m) Total length.