CN111630429A - Zoom optical system for endoscope and endoscope - Google Patents

Zoom optical system for endoscope and endoscope Download PDF

Info

Publication number
CN111630429A
CN111630429A CN201980009522.9A CN201980009522A CN111630429A CN 111630429 A CN111630429 A CN 111630429A CN 201980009522 A CN201980009522 A CN 201980009522A CN 111630429 A CN111630429 A CN 111630429A
Authority
CN
China
Prior art keywords
lens group
lens
endoscope
optical system
end position
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN201980009522.9A
Other languages
Chinese (zh)
Other versions
CN111630429B (en
Inventor
那须幸子
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hoya Corp
Original Assignee
Hoya Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hoya Corp filed Critical Hoya Corp
Publication of CN111630429A publication Critical patent/CN111630429A/en
Application granted granted Critical
Publication of CN111630429B publication Critical patent/CN111630429B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/04—Reversed telephoto objectives
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
    • G02B15/163—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
    • G02B23/24—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
    • G02B23/26—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes using light guides

Abstract

The zoom optical system for an endoscope includes, in order from the object side, a first lens group having negative power and a second lens group having positive power and being movable on the optical axis. The first lens group includes, in order from the object side, a negative lens having a concave surface facing the image side and a positive lens having a convex surface facing the object side, and the second lens group includes a positive lens having a convex surface facing the object sideA cemented lens in which positive lenses are cemented. A combined focal length f of the first and second lens groups1[mm]、f2[mm]Synthetic focal length f of the entire system for long-distance observationw[mm]Synthetic focal length f of the whole system under magnification observationt[mm]And a focal length f of a positive lens closest to an image side in the first lens groups1Satisfies 0.6 < | fs1/f1|＜1.6、1.2＜ft/fw＜1.4、0.5＜|f2/f1|＜0.8。

Description

Zoom optical system for endoscope and endoscope
Technical Field
The present invention relates to a variable power optical system for an endoscope used for an endoscope objective lens unit, and an endoscope.
Background
Nowadays, endoscopes are used for examining living tissues inside the human body. An endoscope includes an imaging element for imaging a living tissue illuminated with illumination light at a distal end portion inserted into a human body, and an objective lens unit attached to the imaging element. In order to miniaturize the front end portion of the objective lens unit, the objective lens unit is required to be extremely small in size and to have high optical performance.
In order to observe a lesion in a detailed manner, an endoscope is equipped with a variable magnification optical system having a variable magnification function. Since it is necessary to enlarge a diseased portion while keeping a constant distance from the lens tip on the object side to the image plane, a configuration having at least one movable lens group is generally used as such a variable power optical system.
In such a variable power optical system, when the first lens group closest to the object side is configured by a lens group having positive power, it is easy to correct aberrations in each positive lens group, so that it is possible to suppress performance degradation due to variable power.
In the case where the first lens group closest to the object side is configured by a lens group having negative power, the total length of the optical system can be shortened, but since the lens group having positive power moves and changes in aberration become large, it is necessary to move other lenses in order to suppress the influence thereof.
For example, a high-performance objective optical system corresponding to a high-pixel image pickup element is known as follows: focusing is possible according to a change in the object point distance and a change in the angle of field hardly occurs at that time (patent document 1).
In this objective optical system, the negative first lens group, the positive second lens group, the aperture stop, and the positive third lens group are arranged in this order from the object side, and focusing is performed for a change in the object point distance by moving only the second lens group, and predetermined conditions are satisfied with respect to the maximum half field angle at the time of long-distance observation, the maximum half field angle at the time of short-distance observation, the focal length of the first lens group, and the focal length of the entire system at the time of long-distance observation.
Documents of the prior art
Patent document
Patent document 1: japanese patent application laid-open No. 4819969
Disclosure of Invention
Problems to be solved by the invention
In the objective optical system described above, although the field angle hardly changes when the magnification is changed, the half field angle at the time of long distance observation is 80.8 degrees at the maximum (see section 0118).
In the current endoscope, a wide angle of visibility is required while maintaining the variable magnification, and for example, the angle of visibility is more than 160 degrees (half field angle 80 degrees) and preferably 165 degrees or more in the long-distance observation.
Accordingly, an object of the present invention is to provide a variable power optical system for an endoscope and an endoscope that have a wide angle of visibility in normal observation (in long-distance observation) in spite of their small size, and that maintain lens performance suitable for observation without reducing magnification in magnification observation.
Means for solving the problems
An aspect of the present invention is a variable power optical system for an endoscope used for an endoscope objective lens unit. The zoom optical system for endoscope
The image pickup device includes, in order from an object side:
a first lens group having negative power; and
a second lens group having a positive power,
the second lens group is moved between a wide-angle end position and a telephoto end position in an optical axis direction with respect to the first lens group as a fixed lens group while keeping a distance from a most object-side lens surface of the first lens group to an image surface constant, thereby magnifying an optical image.
The first lens group
A negative lens having a concave surface facing the image side and a positive lens having a convex surface facing the object side in this order from the object side,
the second lens group
The lens includes, in order from the object side, at least a positive lens having a convex surface facing the object side and a cemented lens formed by cementing a negative lens and a positive lens.
Setting a composite focal length of the first lens group to f1[mm]Setting a composite focal length of the second lens group to f2[mm]Setting a composite focal length of the entire system when the second lens group is at the wide-angle end position as fw[mm]Setting a composite focal length of the entire system when the second lens group is at the telephoto end position as ft[mm]Setting a focal length of the positive lens in the first lens group to fs1And then, satisfy:
(1)0.6＜|fs1/f1|＜1.6、
(2)1.2＜ft/fw＜1.4、
(3)0.5＜|f2/f1|＜0.8。
preferably, the variable power optical system for an endoscope satisfies:
(4)2.0＜|fs1/fw|＜4.0。
further, it is preferable that the variable magnification optical system for an endoscope satisfies:
(5)2.0＜|f1/fw|＜4.0。
preferably, a radius of curvature of an object-side surface of the positive lens in the first lens group is rp1[ mm ]]The curvature radius of the image-side surface of the positive lens in the first lens group is rp2(rp2 ≠ rp1) [ mm]Definition of SF1When (rp1+ rp2)/(rp1-rp2),
the variable power optical system for an endoscope satisfies:
(6)-8.0＜SF1＜-2.0。
preferably, the variable power optical system for an endoscope includes a third lens group which is a fixed lens group on the image side with respect to the second lens group, and the third lens group includes at least a positive lens having a convex surface facing the object side.
Preferably, a stop is disposed on the object side of the second lens group between the first lens group and the second lens group,
the stop moves integrally with the second lens group.
Another aspect of the present invention is an endoscope including:
a variable power optical system for the endoscope; and
and an imaging element that receives light of an image of the object imaged by the variable magnification optical system for an endoscope.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the variable power optical system for an endoscope and the endoscope described above, although small in size, there is a wide angle of visibility at the time of normal observation (at the time of long-distance observation), and lens performance suitable for observation can be maintained without reducing the magnification at the time of magnification observation.
Drawings
Fig. 1 is a view schematically showing an example of the configuration of an endoscope in which the variable magnification optical system for an endoscope according to the present embodiment is mounted.
Fig. 2 (a) and (b) are views showing an example of the configuration of the variable magnification optical system for an endoscope according to the embodiment.
Fig. 3 (a) and (b) are views showing an example of the configuration of the variable magnification optical system for an endoscope according to another embodiment.
Fig. 4 (a) and (b) are views showing an example of the configuration of a variable magnification optical system for an endoscope according to still another embodiment.
Fig. 5 (a) and (b) are views showing an example of the configuration of a variable magnification optical system for an endoscope according to still another embodiment.
Fig. 6 (a) and (b) are views showing an example of the configuration of a variable magnification optical system for an endoscope according to still another embodiment.
Fig. 7 (a) and (b) are views showing an example of the configuration of a variable magnification optical system for an endoscope according to still another embodiment.
Fig. 8 (a) to (d) are various aberration diagrams at the wide-angle end position of the second lens group G2 in example 1, and (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 1.
Fig. 9 (a) to (d) are various aberration diagrams at the wide-angle end position of the second lens group G2 in example 2, and (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 2.
Fig. 10 (a) to (d) are various aberration diagrams at the wide-angle end position of the second lens group G2 in example 3, and (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 3.
Fig. 11 (a) to (d) are various aberration diagrams at the wide-angle end position of the second lens group G2 in example 4, and (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 4.
Fig. 12 (a) to (d) are various aberration diagrams at the wide-angle end position of the second lens group G2 in example 5, and (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 5.
Fig. 13 (a) to (d) are various aberration diagrams at the wide-angle end position of the second lens group G2 in example 6, and (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 6.
Detailed Description
The following describes the variable magnification optical system for an endoscope and the endoscope according to the present embodiment with reference to the drawings. Fig. 1 is an external view showing an external appearance of an endoscope 1 according to an embodiment of the present invention.
As shown in fig. 1, the endoscope 1 includes an insertion portion flexible tube 11 externally wrapped with a flexible sheath 11a. The bending portion 14 provided at the tip end portion of the insertion portion flexible tube 11 is bent in accordance with the rotational operation of the bending operation knob 13a from the hand operation portion 13 coupled to the root end of the insertion portion flexible tube 11. The bending mechanism is a known mechanism embedded in a general endoscope, and bends the bending portion 14 by pulling an operation wire in conjunction with a rotational operation of the bending operation handle 13a. The distal end of the bent portion 14 is connected to the proximal end of the distal end portion 12 which is externally covered with a rigid resin case. The direction of the distal end portion 12 changes in accordance with the bending motion by the rotational operation of the bending operation knob 13a, whereby the imaging region of the endoscope 1 moves.
The variable power optical system 100 for an endoscope used as an objective lens unit is embedded in the interior of the resin case of the distal end portion 12, and the variable power optical system 100 for an endoscope has a wide visible angle at the time of normal observation (at the time of distant observation) and maintains lens performance suitable for observation without reducing magnification at the time of magnification observation. In order to acquire image data of an object in an imaging region, the variable power optical system for endoscope 100 forms an image of light from the object on a light receiving surface of an imaging element (not shown) and causes the imaging element to receive the light. Examples of the imaging element include a CCD (Charge Coupled Device) image sensor and a CMOS (Complementary Metal oxide semiconductor) image sensor.
Fig. 2 (a) and (b) are views showing an example of the configuration of the endoscopic magnification-varying optical system 100 according to the embodiment. Fig. 2 (a) shows a state where the second lens group G2 is in the wide-angle end position and normal observation (distant observation) is performed in the endoscope 1. Fig. 2 (b) shows a state in which the second lens group G2 is at the telephoto end position and enlarged in the endoscope 1.
As shown in fig. 2 (a) and (b), the endoscopic magnification-varying optical system 100 includes, in order from the object (subject) side, a first lens group G1 having negative power, an aperture stop S, a second lens group G2 having positive power, and a third lens group G3 having positive power. The zoom optical system 100 for an endoscope is configured to change the focal length of the entire system (the combined focal length from the first lens group G1 to the third lens group G3) while maintaining a focused state and to magnify an optical image by moving the second lens group G2 between a wide-angle end position and a telephoto end position in the optical axis direction AX relative to the first lens group G1, which is a fixed lens group, while maintaining a constant distance from the most object-side lens surface of the first lens group G1 to the image plane (i.e., the total length of the zoom optical system 100 for an endoscope). That is, when the object distance from the lens surface closest to the object side to the object becomes shorter, the second lens group G2 is moved to maintain the in-focus state so that the object forms an image on the light receiving surface of the imaging element according to the object distance. When the second lens group G2 is in the wide-angle end position, the viewing angle of the variable power optical system for endoscope 100 exceeds 160 ° (the half field angle exceeds 80 °). Each lens constituting each lens group G1, G2, G3 has a shape rotationally symmetric around the optical axis AX of the variable power optical system for endoscope 100. A correction color filter for the image pickup element is disposed at the rear stage of the third lens group G3. The correction color filter is adhered to a glass cover, not shown, which protects the imaging element. The "x" in the figure indicates an imaging position on the optical axis AX.
With the second lens group G2 at the wide-angle end position, normal observation (telephoto observation) is performed in the endoscope 1, and observation is performed in a state of lowest magnification. When the second lens group G2 is at the telephoto end position, the endoscope 1 performs enlarged observation of a lesion or the like, and observes with the highest magnification. The second lens group G2 is movable to an arbitrary position between the wide-angle end position and the telephoto end position in accordance with the distance of an object from the object to the object-side surface of the first lens group G, so as to form an image on the light receiving surface of the photographing element. The visible angle is expanded to the widest at the wide-angle end position.
The first lens group G1 includes, in order from the object side, at least a negative lens (lens L1 in the example of fig. 2) having a concave surface facing the image side and a positive lens L3 having a convex surface facing the object side, and is a lens group having negative power disposed on the object side with respect to the stop S. By "at least have" is meant that there may be other optical elements such as a lens, a flat plate, etc. between the lens L1 and the lens L3 in the first lens group G1, and there may be optical elements on the image side of the lens L3. The same meaning is also expressed as "having at least" in the second lens group G2 and the third lens group G3, which will be described later. As shown in fig. 2 (a), the first lens group G1 includes a positive lens L2 whose object-side surface is a flat surface and whose image-side surface is a convex surface.
The second lens group G2 is a lens group having positive power disposed immediately behind the stop S, and is configured to include, in order from the object side, a lens L4 which is a positive lens having a convex surface facing the object side, and a cemented lens CL1 formed by cementing two positive and negative lenses L5 and L6, in order to suppress occurrence of chromatic aberration. In the example shown in fig. 2 (a), the second lens group G2 includes a lens L7 that is a positive lens on the image side of the cemented lens CL 1.
In the cemented lens CL1, the lens L5 that is a negative lens is disposed on the object side, and the lens L6 that is a positive lens is disposed on the image side.
In order to magnify an optical image formed on the light receiving surface of the imaging element, the second lens group G2 moves in the optical axis AX direction integrally with the stop S. By moving the second lens group G2 integrally with the stop S, occurrence of astigmatism when the second lens group G2 is at the telephoto end position can be effectively suppressed.
The stop S is a plate-like member having a predetermined circular opening centered on the optical axis AX, or a light shielding film formed by coating a region other than a predetermined circular region centered on the optical axis AX on the object side surface of the lens L4, specifically, on the lens surface of the second lens group G2 closest to the stop S in the example shown in fig. 2 (a). The thickness of the aperture S is extremely thin compared to the thickness of each optical lens constituting the variable magnification optical system 100 for an endoscope, and is negligible in calculating the optical performance of the variable magnification optical system 100 for an endoscope.
On the image side of the second lens group G2, a third lens group G3 is disposed. The third lens group G3 is composed of a lens L8 which is a positive lens having positive power and a convex surface facing the object side. The third lens group G3 is a fixed lens group, like the first lens group G1. Although the third lens group G3 is provided in the example shown in fig. 2 (a), the third lens group G3 may not be provided. The third lens group G3 is preferably provided in view of suppressing the exit angle of light from the exit pupil at the time of magnification variation toward the imaging element by providing the third lens group G3 as a positive lens having a convex surface directed to the object side.
The lens group may be a lens group composed of a single lens, like the third lens group G3, in addition to a configuration in which a plurality of lenses are provided, like the first lens group G1 or the second lens group G2.
In the variable power optical system 100 for an endoscope, the lens L3 which is the most positive lens on the aperture side in the first lens group G1 is a positive meniscus lens having a convex surface facing the object side, whereby the incident light beam height can be suppressed. As described above, by moving the stop S integrally with the second lens group G2, astigmatism can be suppressed from occurring during magnification observation.
In addition, by disposing the cemented lens CL1 near the center of the second lens group G2, chromatic aberration variation at the time of magnification variation can be suppressed.
Here, when the combined focal length of the first lens group G1 is set to f1[mm]F is the combined focal length of the second lens group G22[mm]Setting the composite focal length of the entire system at the wide-angle end position of the second lens group G2 as fw[mm]The combined focal length of the entire system at the telephoto end position of the second lens group G2 is set to ft[mm]The focal length of the positive lens (lens L3 in the example shown in fig. 2 (a)) located on the most image side in the first lens group G1 is set to fs1The variable power optical system 100 for an endoscope satisfies:
0.6 < | f of formula (1)s1/f1|＜1.6、
Formula (2)1.2 < ft/fw＜1.4、
0.5 < | f of formula (3)2/f1|＜0.8。
The above expression (1) indicates the focal length f of the lens L3 which is a meniscus lens in the first lens group G1s1Combined focal length f with the first lens group G11The ratio of (a) to (b). Satisfying the expression (1) makes it possible to reduce the diameter of the variable power optical system 100 for an endoscope while widening the viewing angle in normal observation (long-distance observation). If focal lengthfs1Combined focal length f with the first lens group G11Absolute value of the ratio of (i) | fs1/f1If | becomes 1.6 or more, the positive power of the lens L3 becomes weak and the outer diameter of the first lens group G1 becomes small, but the lens performance tends to be greatly reduced due to the deviation of the center of the lens from the optical axis AX1 (due to decentering). In addition, large coma aberration and distortion aberration occur, and it becomes difficult to correct them. On the other hand, the absolute value of the ratio | fs1/f1If |, is 0.6 or less, the positive power of the lens L3 becomes strong, and the outer diameter of the first lens group G1 becomes large and the entire length of the variable power optical system 100 for an endoscope also becomes long in order to secure a viewing angle.
The above equation (2) represents the focal length f of the entire system at the time of normal observation (distant observation)wAnd the focal length f of the whole system under magnification observationwRatio f oft/fwThe range of (1). The expression (2) is a conditional expression for bringing the magnification of the image into an appropriate range with respect to the observation distance. If ratio ft/fwWhen the magnification is 1.4 or more, the variation in F number due to the magnification change becomes large, and the resolution in the enlarged view is reduced. If ratio ft/fwWhen the magnification becomes 1.2 or less, the image magnification during the enlarged observation becomes small, and the image cannot be observed sufficiently.
The above formula (3) shows the combined focal length f of the second lens group G22Combined focal length f with the first lens group G11Range of ratios of (a) to (b). By satisfying the formula (3), the zoom optical system 100 for an endoscope can secure a movement amount of the second lens group G2 necessary for zooming, although it is small in size. Absolute value of ratio | f2/f1If |, is 0.8 or more, the power of the second lens group G2 becomes weak, and the entire length of the variable power optical system 100 for an endoscope becomes long because the amount of movement accompanying variable power becomes long. Absolute value of ratio | f2/f1If |, is 0.5 or less, the power of the second lens group G2 becomes stronger, and the amount of movement associated with the magnification change becomes smaller, but the petz valve sum becomes negative and its absolute value becomes larger, and it becomes difficult to correct field curvature.
Therefore, by configuring the variable power optical system 100 for an endoscope so as to satisfy the above equations (1) to (3), it is possible to provide a variable power optical system for an endoscope which has a wide viewing angle in normal observation (in long-distance observation) in spite of its small size and which has a lens performance suitable for observation without reducing the magnification in magnification observation.
Fig. 3 (a) and (b) are views showing an example of the configuration of the variable magnification optical system for endoscope 100 according to another embodiment. Fig. 3 (a) shows a state where the second lens group G2 is in the wide-angle end position and normal observation (distant observation) is performed in the endoscope 1. Fig. 3 (b) shows a state in which the second lens group G2 is at the telephoto end position and an enlarged view is taken through the endoscope 1.
As shown in fig. 3 (a) and (b), the endoscopic magnification-varying optical system 100 includes, in order from the object (subject) side, a first lens group G1 having negative power, an aperture stop S, a second lens group G2 having positive power, and a third lens group G3 having positive power.
In contrast to the configuration of the variable power optical system 100 for an endoscope shown in fig. 2 (a) and (b), in the configuration of the variable power optical system 100 for an endoscope shown in fig. 3 (a) and (b), the lens L2 is not provided, and instead, a lens L9 which is a positive lens having a convex surface on the object side and a convex surface on the image side is provided as the third lens group G3. Further, unlike the configurations shown in fig. 2 (a) and (b), in the configuration of the variable power optical system for endoscope 100 shown in fig. 3 (a) and (b), the lens L8 is a part of the second lens group G2 and is moved.
In the case of such a configuration, by satisfying the above-described equations (1) to (3), it is possible to reduce the diameter of the zoom optical system 100 for an endoscope while maintaining a wide viewing angle in normal observation (long-distance observation), and it is possible to secure a moving amount of the second lens group G2 necessary for zooming while bringing the zoom ratio of the image into an appropriate range with respect to the observation distance. That is, the zoom optical system for an endoscope can be made compact, has a wide viewing angle in normal observation (in long-distance observation), and can maintain lens performance suitable for observation without reducing magnification in magnification observation.
Fig. 4 (a) and (b) are views showing an example of the configuration of the endoscopic magnification-varying optical system 100 according to still another embodiment. Fig. 4 (a) shows a state where the second lens group G2 is in the wide-angle end position and normal observation (distant observation) is performed in the endoscope 1. Fig. 4 (b) shows a state where the second lens group G2 is at the telephoto end position and enlarged in the endoscope 1.
As shown in fig. 4 (a) and (b), the endoscopic magnification-varying optical system 100 includes, in order from the object (subject) side, a first lens group G1 having negative power, an aperture stop S, a second lens group G2 having positive power, and a third lens group G3 having positive power.
Although the configuration is the same as that of the variable power optical system for an endoscope 100 shown in fig. 2 (a) and (b), a flat plate is used in place of the lens L2 shown in fig. 2 (a) and (b) in the configuration of the variable power optical system for an endoscope 100 shown in fig. 4 (a) and (b). In fig. 4 (a) and (b), the same symbol L2 is shown, but it is a flat plate L2.
Even in the case of such a configuration, by satisfying the above-described equations (1) to (3), it is possible to reduce the diameter of the zoom optical system 100 for an endoscope while maintaining a wide viewing angle in normal observation (long-distance observation), and it is possible to secure a moving amount of the second lens group G2 necessary for zooming while bringing the zoom ratio of the image into an appropriate range with respect to the observation distance. That is, the zoom optical system for an endoscope can be made compact, has a wide viewing angle in normal observation (in long-distance observation), and can maintain lens performance suitable for observation without reducing magnification in magnification observation.
Fig. 5 (a) and (b) are views showing an example of the configuration of the endoscopic magnification-varying optical system 100 according to still another embodiment. Fig. 5 (a) shows a state where the second lens group G2 is in the wide-angle end position and normal observation (distant observation) is performed in the endoscope 1. Fig. 5 (b) shows a state where the second lens group G2 is at the telephoto end position and enlarged in the endoscope 1.
As shown in fig. 5 (a) and (b), the endoscopic magnification-varying optical system 100 includes, in order from the object (subject) side, a first lens group G1 having negative power, an aperture stop S, and a second lens group G2 having positive power.
In comparison with the configurations of the variable magnification optical system for an endoscope 100 shown in fig. 2 (a) and (b), the configuration of the variable magnification optical system for an endoscope 100 shown in fig. 5 (a) and (b) does not include the lens L2. The lens L9 is also absent compared with the configuration of the variable power optical system for endoscope 100 shown in fig. 3 (a) and (b). That is, the variable magnification optical system 100 for an endoscope shown in fig. 5 (a) and (b) has a configuration in which the third lens group G3 is not provided and the lenses L4 to L8 move integrally with the stop S.
Even in the case of such a configuration, by satisfying the above-described equations (1) to (3), it is possible to reduce the diameter of the zoom optical system 100 for an endoscope while maintaining a wide viewing angle in normal observation (long-distance observation), and it is possible to secure a moving amount of the second lens group G2 necessary for zooming while bringing the zoom ratio of the image into an appropriate range with respect to the observation distance. That is, the zoom optical system for an endoscope can be made compact, has a wide viewing angle in normal observation (in long-distance observation), and can maintain lens performance suitable for observation without reducing magnification in magnification observation.
Fig. 6 (a) and (b) are views showing an example of the configuration of the endoscopic magnification-varying optical system 100 according to still another embodiment. Fig. 6 (a) shows a state where the second lens group G2 is in the wide-angle end position and normal observation (distant observation) is performed in the endoscope 1. Fig. 6 (b) shows a state where the second lens group G2 is at the telephoto end position and enlarged in the endoscope 1.
As shown in fig. 6 (a) and (b), the endoscopic magnification-varying optical system 100 includes, in order from the object (subject) side, a first lens group G1 having negative power, an aperture stop S, a second lens group G2 having positive power, and a third lens group G3 having positive power.
In comparison with the configurations of the variable magnification optical system for an endoscope 100 shown in fig. 2 (a) and (b), the configuration of the variable magnification optical system for an endoscope 100 shown in fig. 6 (a) and (b) does not include the lens L2. Unlike the configuration of the variable power optical system 100 for an endoscope shown in fig. 5 (a) and (b), in the configuration of the variable power optical system 100 for an endoscope shown in fig. 6 (a) and (b), the lens L8 does not move as the third lens group G3 as shown in fig. 6 (b).
Even in the case of such a configuration, by satisfying the above-described equations (1) to (3), it is possible to reduce the diameter of the zoom optical system 100 for an endoscope while maintaining a wide viewing angle in normal observation (long-distance observation), and it is possible to secure a moving amount of the second lens group G2 necessary for zooming while bringing the zoom ratio of the image into an appropriate range with respect to the observation distance. That is, the zoom optical system for an endoscope can be made compact, has a wide viewing angle in normal observation (in long-distance observation), and can maintain lens performance suitable for observation without reducing magnification in magnification observation.
Fig. 7 (a) and (b) are views showing an example of the configuration of the endoscopic magnification-varying optical system 100 according to still another embodiment. Fig. 7 (a) shows a state where the second lens group G2 is normally observed (telephoto observed) in the endoscope 1 at the wide-angle end position. Fig. 7 (b) shows a state where the second lens group G2 is at the telephoto end position and enlarged in the endoscope 1.
As shown in fig. 7 (a) and (b), the endoscopic magnification-varying optical system 100 includes, in order from the object (subject) side, a first lens group G1 having negative power, an aperture stop S, a second lens group G2 having positive power, and a third lens group G3 having positive power.
Although the configuration is the same as that of the variable power optical system 100 for an endoscope shown in fig. 2 (a) and (b), in the configuration of the variable power optical system 100 for an endoscope shown in fig. 7 (a) and (b), the lens L2 shown in fig. 7 (a) and (b) is not a positive lens whose image-side surface is a convex surface, but is a negative lens whose image-side surface is a concave surface.
Even in the case of such a configuration, by satisfying the above-described equations (1) to (3), it is possible to reduce the diameter of the zoom optical system 100 for an endoscope while maintaining a wide viewing angle in normal observation (long-distance observation), and it is possible to secure a moving amount of the second lens group G2 necessary for zooming while bringing the zoom ratio of the image into an appropriate range with respect to the observation distance. That is, the zoom optical system for an endoscope can be made compact, has a wide viewing angle in normal observation (in long-distance observation), and can maintain lens performance suitable for observation without reducing magnification in magnification observation.
The configuration of the variable magnification optical system 100 for an endoscope shown in fig. 2 to 7 is preferably provided with the following aspects.
That is, according to an embodiment of the variable magnification optical system for endoscope 100, the variable magnification optical system for endoscope 100 preferably satisfies:
2.0 < | f of formula (4)s1/fw|＜4.0。
Expression (4) indicates the focal length f of the lens L3 which is a positive lens on the side closest to the stop S in the first lens group G1s1Focal length f of the whole system in comparison with the conventional observation (long-distance observation)wRange of ratios of (a) to (b). By satisfying the formula (4), it is possible to suppress aberration occurring in the first lens group G1 and to suppress a change in lens performance at the time of magnification change. Absolute value of ratio | fs1/fwIf | becomes 4.0 or more, the positive power of the lens L3 becomes weak, and it becomes difficult to cancel out the aberration occurring in the negative lens. In addition, if the lens aberration is to be suppressed within an appropriate range, the angle of visibility is narrowed. Absolute value of ratio | fs1/fwIf | becomes 2.0 or less, since the positive power of the lens L3 becomes too strong, the occurrence of distortion aberration becomes serious and peripheral resolution decreases in normal observation. In addition, it becomes difficult to correct aberrations occurring in the positive lens during magnification observation, and therefore it becomes difficult to maintain optical performance.
In addition, according to an embodiment of the variable magnification optical system for endoscope 100, it is preferable that the variable magnification optical system for endoscope 100 satisfies:
2.0 < | f of formula (5)1/fw|＜4.0。
Expression (5) is a composite focal length f of the first lens group G11Focal length f of the whole system in comparison with the conventional observation (long-distance observation)wRatio of (a) | f1/fwThe range of |And (5) enclosing. By satisfying the conditional expression (5), the effective diameter of the first lens group G1 can be suppressed. Absolute value of ratio | f1/fwIf | is 2.0 or less, the negative power of the first lens group G1 becomes stronger, and the negative power of the object side lens L1 becomes stronger, so that coma aberration becomes larger. Absolute value of ratio | f1/fwIf | becomes 4.0 or more, in order to secure negative power of the first lens group G1, it is necessary to increase the effective diameter of the negative lens located on the most object side.
In addition, according to an embodiment of the variable magnification optical system for endoscope 100, it is preferable that the variable magnification optical system for endoscope 100 satisfies:
formula (6) -8.0 < SF1＜-2.0。
Here, the radius of curvature of the object-side surface of the positive lens closest to the image side in the first lens group G1, lens L3 in the example shown in fig. 2 (a), is rp1[ mm []The curvature radius of the image-side surface of the most image-side positive lens in the first lens group G1 is rp2(rp2 ≠ rp1) [ mm []When, define SF1＝(rp1+rp2)/(rp1-rp2)。
SF1The shape of the most image-side positive lens in the first lens group G1, lens L3 in the example shown in fig. 2 (a), is defined. By satisfying the formula (6), it is possible to suppress image distortion caused by the lens at the time of normal observation (long-distance observation) while maintaining a state where the visible angle is wide, and it is possible to suppress a change in lens aberration (caused by decentering) caused by the center of the lens being deviated from the optical axis AX 1. If SF1When the value is-8.0 or less, the curvature radius rp1 of the object-side surface becomes large, and it becomes difficult to correct the aberration of the lens at the time of magnification change because the occurrence of each aberration is suppressed. If SF1When the surface on the object side becomes-2.0 or more, the radius of curvature rp1 becomes small and the strain becomes large. In addition, variation in lens aberration (caused by decentering) caused by the center of the lens being deviated from the optical axis AX1 increases and lens performance degradation becomes large.
Next, the lens performance of the configuration of the variable power optical system 100 for an endoscope shown in fig. 2 to 7 will be described with reference to examples 1 to 6.
(example 1)
The configuration of the variable magnification optical system 100 for an endoscope shown in (a) and (b) of fig. 2 was used as example 1. Specific numerical values (design values) of example 1 are shown in table 1. The surface number NO shown in the upper column (surface data) of table 1 corresponds to the surface symbol rn (n is a natural number) in fig. 2 (a) except for the surface number 7 corresponding to the stop S. In the upper column of Table 1, R [ mm ] represents the radius of curvature of each surface of an optical member including a lens, D [ mm ] represents the thickness of the optical member or the optical member interval on the optical axis AX, N (D) represents the refractive index of a D-line (wavelength 588nm), and VD represents the Abbe number of the D-line.
The lower column (various data) of table 1 shows the specifications (effective F-number, combined focal length [ mm ] of the entire system, optical magnification, half field angle [ degree ], image height [ mm ], group interval D6[ mm ], group interval D14[ mm ]) of example 1.
The group interval D6 is the interval between the first lens group G1 and the second lens group G2. The group interval D14 is the interval between the second lens group G2 and the third lens group G3. The group interval D6 and the group interval D14 vary depending on the magnification-varying position (wide-angle end position and telephoto end position). In table 1, the wide-angle end position at which the variable magnification optical system 100 for an endoscope is located is indicated as "wide angle", and the telephoto end position is indicated as "telephoto".
[ TABLE 1 ]
Figure BDA0002595897440000161
Fig. 8 (a) to (d) are various aberration diagrams when the second lens group G2 is at the wide-angle end position in example 1. Fig. 8 (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 1. FIG. 8 (a) and (e) show spherical aberration and axial chromatic aberration on the d-line, g-line (wavelength 436nm) and C-line (wavelength 656 nm). In fig. 8, (b) and (f) show chromatic aberration of magnification for d-line, g-line, and C-line. In fig. 8 (a), (b), (e), and (f), the solid line indicates the aberration in the d-line, the broken line indicates the aberration in the g-line, and the alternate long and short dash line indicates the aberration in the C-line. Fig. 8 (c) and (g) show astigmatism. In fig. 8 (c) and (g), the solid line represents the sagittal component "S" and the broken line represents the radial component "M". Fig. 8 (d) and (h) show distortion aberrations. In fig. 8, (a) to (c) and (e) to (g) have vertical axes representing image heights and horizontal axes representing aberration amounts. In fig. 8, (d) and (h) have vertical axes representing image height and horizontal axes representing distortion factor (%). The descriptions of table 1 of example 1 and (a) to (h) of fig. 8 are also applied to the tables and drawings of the following examples.
In example 1, the half angle of view of the second lens group G2 at the wide-angle end position was set to 85.6 degrees (visible angle was 171.2 degrees), and the effective diameter of the lens L1 was suppressed, so that the entire size of the variable power optical system 100 for an endoscope in the radial direction was suppressed. Further, aberrations are suppressed well at any of the wide-angle end position and the telephoto end position without reducing the magnification in the magnified observation (see (a) to (h) of fig. 8).
(example 2)
The configurations of the variable magnification optical system 100 for an endoscope shown in (a) and (b) of fig. 3 were used as example 2.
Specific numerical values (design values) of example 2 are shown in table 2.
In the lower column (various data) of table 2, instead of the group interval D6[ mm ] of table 1, a group interval D4[ mm ] was changed, and a group interval D4 was an interval between the first lens group G1 and the second lens group G2.
[ TABLE 2 ]
Figure BDA0002595897440000181
Fig. 9 (a) to (d) are various aberration diagrams when the second lens group G2 is at the wide-angle end position in example 2. Fig. 9 (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 2.
In example 2 as well, the effective diameter of the lens L1 can be suppressed while the half angle of view of the second lens group G2 at the wide-angle end position is 88.0 degrees (viewing angle 176.0 degrees), and the radial dimension of the entire endoscopic variable magnification optical system 100 can be suppressed. Further, aberrations are suppressed well at any of the wide-angle end position and the telephoto end position without reducing the magnification in the magnified observation (see (a) to (h) of fig. 9).
(example 3)
The configuration of the variable magnification optical system 100 for an endoscope shown in (a) and (b) of fig. 4 was used as example 3.
Specific numerical values (design values) of example 3 are shown in table 3.
[ TABLE 3 ]
Figure BDA0002595897440000191
Fig. 10 (a) to (d) are various aberration diagrams when the second lens group G2 is at the wide-angle end position in example 3. Fig. 10 (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 3.
In example 3, the effective diameter of the lens L1 can be reduced while the half angle of view of the second lens group G2 at the wide-angle end position is set to 86.7 degrees (visible angle 173.4 degrees), and the radial dimension of the entire variable power optical system for endoscope 100 can be reduced. Further, aberrations are suppressed well at any of the wide-angle end position and the telephoto end position without reducing the magnification in the magnified observation (see (a) to (h) of fig. 10).
(example 4)
The configuration of the variable magnification optical system 100 for an endoscope shown in (a) and (b) of fig. 5 was used as example 4.
Specific numerical values (design values) of example 4 are shown in table 4. In the lower column (various data) of table 4, instead of the group interval D6[ mm ] of table 1, a group interval D4[ mm ] was changed, and a group interval D4 was an interval between the first lens group G1 and the second lens group G2.
[ TABLE 4 ]
Figure BDA0002595897440000201
Fig. 11 (a) to (d) are various aberration diagrams at the wide-angle end position of the second lens group G2 in example 4. Fig. 11 (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 4.
In example 4, the effective diameter of the lens L1 can be reduced while the half angle of view of the second lens group G2 at the wide-angle end position is 86.6 degrees (visible angle 173.2 degrees), and the radial dimension of the entire variable power optical system for endoscope 100 can be reduced. Further, aberrations are suppressed well at any of the wide-angle end position and the telephoto end position without reducing the magnification in the magnified observation (see (a) to (h) of fig. 11).
(example 5)
The configuration of the variable magnification optical system 100 for an endoscope shown in (a) and (b) of fig. 6 was used as example 5.
Specific numerical values (design values) of example 5 are shown in table 5. In the lower column (various data) of table 5, instead of the group interval D6[ mm ] of table 1, it became the group interval D4[ mm ], instead of the group interval D14 becoming the group interval D12, the group interval D4 is the interval between the first lens group G1 and the second lens group G2. The group interval D12 is the interval between the second lens group G2 and the third lens group G3.
[ TABLE 5 ]
Figure BDA0002595897440000221
Fig. 12 (a) to (d) are various aberration diagrams when the second lens group G2 is at the wide-angle end position in example 5. Fig. 12 (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 5.
In example 5 as well, the effective diameter of the lens L1 can be suppressed while setting the half angle of view of the second lens group G2 at the wide-angle end position to 86.3 degrees (visible angle 172.6 degrees), and the radial dimension of the entire variable power optical system for endoscope 100 can be suppressed. Further, aberrations are suppressed well at any of the wide-angle end position and the telephoto end position without reducing the magnification in the magnified observation (see (a) to (h) of fig. 12).
(example 6)
The configurations of the variable magnification optical system 100 for an endoscope shown in (a) and (b) of fig. 7 were used as example 6.
Specific numerical values (design values) of example 6 are shown in table 6.
[ TABLE 6 ]
Figure BDA0002595897440000231
Fig. 13 (a) to (d) are various aberration diagrams when the second lens group G2 is at the wide-angle end position in example 6. Fig. 13 (e) to (h) are various aberration diagrams at the telephoto end position of the second lens group G2 in example 6.
In example 6 as well, the effective diameter of the lens L1 can be suppressed while the half angle of view of the second lens group G2 at the wide-angle end position is 86.2 degrees (visible angle is 172.4 degrees), and the radial dimension of the entire variable power optical system for endoscope 100 can be suppressed. Further, aberrations are suppressed well at any of the wide-angle end position and the telephoto end position without reducing the magnification in the magnified observation (see (a) to (h) of fig. 13).
Table 7 shows the ratios of expressions (1) to (6) calculated from the respective dimensions shown in tables 1 to 6, or the absolute values of the ratios.
[ TABLE 7 ]
Example 1 Examples2 Example 3 Example 4 Example 5 Example 6
(1)|fs1/f1| 1.25 1.17 1.08 1.45 1.10 0.89
(2)ft/fw 1.30 1.35 1.31 1.27 1.32 1.31
(3)|f2/f1| 0.66 0.57 0.68 0.65 0.71 0.63
(4)|fB1/fw| 3.64 3.69 3.14 3.56 3.08 2.79
(5)|f1/fw| 2.92 3.15 2.91 2.45 2.80 3.14
(6)SF1 -7.16 -5.11 -4.55 -6.44 -4.75 -3.08
As shown in table 7, the above-described formulas (1) to (3) were satisfied in each of examples 1 to 6. Thus, in each of the embodiments 1 to 6, the lens has a wide viewing angle at the time of normal observation (at the time of long-distance observation) in spite of its small size, and can maintain the lens performance suitable for observation without reducing the magnification at the time of magnification observation. In each of the examples satisfying the expressions (4) to (6), the above-described effects are further exhibited.
The variable magnification optical system for an endoscope and the endoscope of the present invention have been described above in detail, but the variable magnification optical system for an endoscope and the endoscope of the present invention are not limited to the above-described embodiments or examples, and it goes without saying that various improvements and modifications can be made within a scope not departing from the gist of the present invention.
Description of the reference numerals
An endoscope; an insertion portion flexible tube; a sheath; a front end portion; a hand operating portion; bending an operating handle; a bend; a variable power optical system for an endoscope.

Claims (7)

1. A variable power optical system for an endoscope, used for an endoscope objective lens unit,
the image pickup device includes, in order from an object side:
a first lens group having negative power; and
a second lens group having a positive power,
the optical image is magnified by moving the second lens group between a wide-angle end position and a telephoto end position in an optical axis direction with respect to the first lens group as a fixed lens group while keeping a distance from a lens surface closest to an object side of the first lens group to an image surface constant,
the first lens group
A negative lens having a concave surface facing the image side and a positive lens having a convex surface facing the object side in this order from the object side,
the second lens group
A positive lens having a convex surface facing the object side and a cemented lens formed by cementing a negative lens and a positive lens in this order from the object side,
setting a composite focal length of the first lens group to f1Setting a composite focal length of the second lens group to f2Setting a composite focal length of the entire system when the second lens group is at the wide-angle end position as fwSetting a composite focal length of the entire system when the second lens group is at the telephoto end position as ftSetting a focal length of the positive lens in the first lens group to fs1And then, satisfy:
(1)0.6＜|fs1/f1|＜1.6、
(2)1.2＜ft/fw＜1.4、
(3)0.5＜|f2/f1|＜0.8，
f1、f2、fw、ftin nm.
2. The variable power optical system for an endoscope according to claim 1,
satisfy (4)2.0 < | fs1/fw|＜4.0。
3. The variable power optical system for an endoscope according to claim 1 or 2,
satisfies (5)2.0 < | f1/fw|＜4.0。
4. The variable power optical system for an endoscope according to any one of claims 1 to 3,
when the curvature radius of the object side surface of the positive lens in the first lens group is rp1, the curvature radius of the image side surface of the positive lens in the first lens group is rp2, and SF is defined1When (rp1+ rp2)/(rp1-rp2),
satisfies (6) -8.0 < SF1＜-2.0，
The units of rp1 and rp2 are mm, and rp2 ≠ rp 1.
5. The variable power optical system for an endoscope according to any one of claims 1 to 4,
and a third lens group which is a fixed lens group including a positive lens having at least a convex surface facing the object side on the image side with respect to the second lens group.
6. The variable power optical system for an endoscope according to any one of claims 1 to 5,
a stop is disposed on the object side of the second lens group between the first lens group and the second lens group,
the stop moves integrally with the second lens group.
7. An endoscope, comprising:
the variable power optical system for an endoscope according to any one of claims 1 to 6; and
and an imaging element that receives light of an image of the object imaged by the variable magnification optical system for an endoscope.
CN201980009522.9A 2018-02-23 2019-02-19 Zoom optical system for endoscope and endoscope Active CN111630429B (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2018-031072 2018-02-23
JP2018031072 2018-02-23
PCT/JP2019/006027 WO2019163744A1 (en) 2018-02-23 2019-02-19 Variable power optical system for endoscope and endoscope

Publications (2)

Publication Number Publication Date
CN111630429A true CN111630429A (en) 2020-09-04
CN111630429B CN111630429B (en) 2022-06-14

Family

ID=67686844

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201980009522.9A Active CN111630429B (en) 2018-02-23 2019-02-19 Zoom optical system for endoscope and endoscope

Country Status (3)

Country Link
JP (1) JP6754916B2 (en)
CN (1) CN111630429B (en)
WO (1) WO2019163744A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113467070A (en) * 2021-07-06 2021-10-01 卓外（上海）医疗电子科技有限公司 Endoscope imaging objective lens with focusing function and focusing method

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000330024A (en) * 1999-05-20 2000-11-30 Asahi Optical Co Ltd Endoscope objective variable power optical system
JP2000330020A (en) * 1999-05-20 2000-11-30 Asahi Optical Co Ltd Endoscope objective variable power optical system
JP2002014282A (en) * 2000-06-29 2002-01-18 Asahi Optical Co Ltd Endoscopic objective variable power optical system
WO2011024657A1 (en) * 2009-08-28 2011-03-03 Hoya株式会社 Variable-power lens system
US20140152887A1 (en) * 2012-12-04 2014-06-05 Samsung Electronics Co., Ltd. Zoom lens and electronic device including the same
JP2015215406A (en) * 2014-05-08 2015-12-03 Hoya株式会社 Zoom lens system
CN205720850U (en) * 2015-04-01 2016-11-23 富士胶片株式会社 Projection zoom lens and projection type image display apparatus
WO2017043352A1 (en) * 2015-09-07 2017-03-16 Hoya株式会社 Variable power optical system for endoscope, and endoscope

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6287926A (en) * 1985-10-14 1987-04-22 Canon Inc Zoom lens
JP3226297B2 (en) * 1991-06-29 2001-11-05 オリンパス光学工業株式会社 Zoom lens and camera with zoom lens
JPH09152552A (en) * 1995-11-28 1997-06-10 Nikon Corp Zoom lens
JP3726271B2 (en) * 1996-06-14 2005-12-14 株式会社ニコン Zoom lens
JP5528211B2 (en) * 2010-05-24 2014-06-25 キヤノン株式会社 Zoom lens and imaging apparatus having the same
JP2016161628A (en) * 2015-02-27 2016-09-05 株式会社タムロン Optical system and image capturing device

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000330024A (en) * 1999-05-20 2000-11-30 Asahi Optical Co Ltd Endoscope objective variable power optical system
JP2000330020A (en) * 1999-05-20 2000-11-30 Asahi Optical Co Ltd Endoscope objective variable power optical system
JP2002014282A (en) * 2000-06-29 2002-01-18 Asahi Optical Co Ltd Endoscopic objective variable power optical system
WO2011024657A1 (en) * 2009-08-28 2011-03-03 Hoya株式会社 Variable-power lens system
US20140152887A1 (en) * 2012-12-04 2014-06-05 Samsung Electronics Co., Ltd. Zoom lens and electronic device including the same
JP2015215406A (en) * 2014-05-08 2015-12-03 Hoya株式会社 Zoom lens system
CN205720850U (en) * 2015-04-01 2016-11-23 富士胶片株式会社 Projection zoom lens and projection type image display apparatus
WO2017043352A1 (en) * 2015-09-07 2017-03-16 Hoya株式会社 Variable power optical system for endoscope, and endoscope
CN107076967A (en) * 2015-09-07 2017-08-18 Hoya株式会社 Endoscope-use variable-power optical system and endoscope

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113467070A (en) * 2021-07-06 2021-10-01 卓外（上海）医疗电子科技有限公司 Endoscope imaging objective lens with focusing function and focusing method

Also Published As

Publication number Publication date
JPWO2019163744A1 (en) 2020-10-22
CN111630429B (en) 2022-06-14
WO2019163744A1 (en) 2019-08-29
JP6754916B2 (en) 2020-09-16

Similar Documents

Publication Publication Date Title
CN107076967B (en) Zoom optical system for endoscope and endoscope
WO2017145265A1 (en) Variable magnification optical system for endoscope and endscope
JP2697822B2 (en) Endoscope objective lens
JP2876252B2 (en) Endoscope objective lens
JP5601924B2 (en) Endoscope variable magnification optical system and endoscope
JP6046322B1 (en) Endoscope variable magnification optical system and endoscope
US6943959B2 (en) Objective optical system
JP5567224B2 (en) Endoscope objective lens and endoscope
CN109932813B (en) Objective optical system for endoscope and endoscope
JP5653243B2 (en) Endoscope optical system and endoscope
WO2017043351A1 (en) Variable power optical system for endoscope, and endoscope
JP5567225B2 (en) Endoscope objective lens and endoscope
CN111630429B (en) Zoom optical system for endoscope and endoscope
CN109557657B (en) Object-targeting optical system for endoscope and endoscope
CN107703606B (en) Objective optical system for endoscope and endoscope
JP4373749B2 (en) Imaging optical system, imaging apparatus for endoscope, and endoscope system
CN109557656B (en) Object-targeting optical system for endoscope and endoscope
JP4394197B2 (en) Endoscope objective variable magnification optical system
JP6877309B2 (en) Objective optical system for endoscopes and endoscopes
WO2023012866A1 (en) Endoscope objective optical system, imaging unit, and endoscope
JP7430966B2 (en) Imaging optical system and imaging device equipped with the same
WO2023100350A1 (en) Endoscope objective optical system and endoscope provided with same
WO2019159778A1 (en) Endoscopic optical system and endoscope
JP6807264B2 (en) Zoom lens and imaging device
JP2023011031A (en) Rear attachment lens and image capturing optical system using the same

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant