CN221616922U - Ji Bianjiao optical adapter and medical endoscope - Google Patents

Abstract

The present application relates to a par-zoom optical adapter and a medical endoscope. The par-zoom optical adapter includes: a first lens with negative optical power, the image side surface of which is a concave surface; a zoom group with positive optical power, including a second lens, a third lens and a fourth lens with positive optical power, the second lens and the third lens are glued together to form a first glued lens group with positive optical power; a compensation group with negative optical power, including a fifth lens, a sixth lens with negative optical power, a seventh lens and an eighth lens, the seventh lens and the eighth lens are glued together to form a second glued lens group with positive optical power; a ninth lens with positive optical power; the zoom group and the compensation group can move along the optical axis. The above-mentioned par-zoom optical adapter can achieve the effects of large aperture, miniaturization, high resolution and good imaging quality.

Description

Full zoom optical adapter and medical endoscope

Technical Field

The present application relates to the technical field of endoscopes, and in particular to a zoom optical adapter and a medical endoscope.

Background Art

A medical endoscope is a medical device that can enter the human body for observation, diagnosis or treatment. A medical endoscope generally includes a camera and an endoscope mirror. The camera is connected to the endoscope mirror through an optical adapter. The optical adapter is used to adjust the light collected by the endoscope mirror and project it to the camera. Optical adapters are divided into fixed focal length adapters (i.e. zoom optical adapters) and variable focal length adapters (i.e. zoom optical adapters) according to their functions.

With the rapid development of medical endoscopes, the industry has higher and higher performance requirements for medical endoscopes. Among them, the quality of medical endoscope imaging directly affects the efficiency and accuracy of diagnosis or treatment. However, the current zoom optical adapter has poor imaging quality, which easily affects the efficiency and accuracy of diagnosis and treatment.

Summary of the invention

Based on this, it is necessary to provide a full zoom optical adapter and a medical endoscope to address the problem of poor imaging quality of the current zoom optical adapter.

A zoom optical adapter comprises, in order from the object side to the image side along the optical axis:

A first lens having negative optical power, wherein the image side surface of the first lens is a concave surface;

A zoom group with positive power, the zoom group including a second lens, a third lens and a fourth lens with positive power in sequence from the object side to the image side along the optical axis, the second lens and the third lens being cemented together to form a first cemented lens group with positive power;

A compensation group with negative optical power, the compensation group including, from the object side to the image side along the optical axis, a fifth lens, a sixth lens with negative optical power, a seventh lens and an eighth lens, the seventh lens and the eighth lens being cemented together to form a second cemented lens group with positive optical power;

a ninth lens having positive refractive power;

The variable power group and the compensation group can move along the optical axis between the first lens and the ninth lens to achieve an optical zoom function.

The above-mentioned par-zoom optical adapter is provided with a magnification group and a compensation group that move along the optical axis. While realizing the optical zoom function, the compensation group can also compensate for the position change of the imaging surface on the optical axis, thereby keeping the position of the imaging surface on the optical axis relatively stable, which is conducive to realizing the par-zoom function, so that the par-zoom optical adapter maintains good imaging quality during the zooming process. At the same time, the first lens and the ninth lens are provided, the first lens with negative optical power can collect light well and expand the aperture, and the ninth lens with positive optical power can effectively converge the light to the imaging surface, thereby improving the compatibility of the par-zoom optical adapter with the image side optical structure, which is conducive to realizing the effects of large aperture and high resolution.

Among them, the negative focal power of the first lens, the positive focal power of the zoom group, the negative focal power of the compensation group and the positive focal power of the ninth lens cooperate to make the light smoothly transition in the full zoom optical adapter, which is conducive to suppressing the generation of aberrations, reducing aberration sensitivity and improving image quality. The negative focal power of the first lens, combined with the design that the image side of the first lens is a concave surface, is conducive to collecting light and diverging it to the image side, increasing the amount of light entering and the aperture of the full zoom optical adapter, and improving the image brightness and image quality. The positive focal power of the first cemented lens group in the zoom group and the positive focal power of the fourth lens are matched with each other, which can smoothly converge and transition the light toward the image side, which is not only conducive to shortening the total length of the par-zoom optical adapter, but also conducive to making the light transition smoother, thereby effectively suppressing aberrations such as distortion of the edge field of view. The focal power and surface design of the first lens and the fifth lens are conducive to making the light fill the pupil and realize a large aperture design, so that the par-zoom optical adapter can meet the relative illumination requirements, improve the edge field of view illumination, and improve the imaging quality of the par-zoom optical adapter in a weak light environment. The negative focal power of the sixth lens and the positive focal power of the second cemented lens group, in combination with the focal power design of the fifth lens and the zoom group, can smoothly transition the light, correct aberrations, reduce the aberration sensitivity of the par-zoom optical adapter, and improve the imaging quality. At the same time, it can also reasonably diverge the light to the image side and expand the aperture of the par-zoom optical adapter. The ninth lens has a positive focal power, which can converge the light reasonably transitioned by each lens on the object side toward the imaging surface, and improve the adaptability of the light to the optical structure on the image side. Therefore, the above-mentioned full-zoom optical adapter can achieve the effects of large aperture, miniaturization, high resolution and good imaging quality, which is beneficial to improving the accuracy of diagnosis and treatment.

In one embodiment, the par-zoom optical adapter satisfies the following condition:

0.2≤(D1/TTL)≤0.4;

0.1≤(D2/TTL)≤0.2;

Wherein, D1 is the stroke of the zoom group on the optical axis, D2 is the stroke of the compensation group on the optical axis, and TTL is the total length of the par-zoom optical adapter.

In one embodiment, the par-zoom optical adapter satisfies the following condition:

22≤|F1/CT1|≤28;

Wherein, F1 is the effective focal length of the first lens, and CT1 is the thickness of the first lens on the optical axis.

In one embodiment, the par-zoom optical adapter satisfies the following condition:

5≤F23/CT23≤7;

Wherein, F23 is the effective focal length of the first cemented lens group, and CT23 is the thickness of the first cemented lens group on the optical axis.

In one embodiment, the par-zoom optical adapter satisfies the following condition:

0.8≤F4/F23≤1.2;

Among them, F4 is the effective focal length of the fourth lens, and F23 is the effective focal length of the first cemented lens group.

In one embodiment, the par-zoom optical adapter satisfies the following condition:

10≤|F5/CT5|≤11; and/or,

10.5≤F9/CT9≤11.5;

Among them, F5 is the effective focal length of the fifth lens, CT5 is the thickness of the fifth lens on the optical axis, F9 is the effective focal length of the ninth lens, and CT9 is the thickness of the ninth lens on the optical axis.

In one embodiment, the par-zoom optical adapter satisfies the following condition:

0.3≤F6/F5≤0.4; and/or,

0.5≤|F6/F78|≤0.6;

Among them, F6 is the effective focal length of the sixth lens, F5 is the effective focal length of the fifth lens, and F78 is the effective focal length of the second cemented lens group.

In one embodiment, the first lens is movable along the optical axis on the object side of the zoom group to achieve an optical focusing function;

And/or, the par-zoom optical adapter further comprises an aperture stop, wherein the aperture stop is disposed between the fifth lens and the sixth lens, and the aperture stop can be synchronously moved along the optical axis with the compensation group.

In one embodiment, the object side surface of the first lens is a concave surface; and/or,

The second lens has positive refractive power, the object side surface of the second lens is convex, and the image side surface is concave, the third lens has positive refractive power, and the object side surface and the image side surface of the third lens are both convex; and/or,

The object side surface of the fourth lens is a convex surface, and the image side surface is a flat surface; and/or,

The fifth lens has negative optical power, and both the object side surface and the image side surface of the fifth lens are concave surfaces; and/or,

The object side surface and the image side surface of the sixth lens are both concave surfaces; and/or,

The seventh lens has negative power, the object side surface of the seventh lens is a plane, and the image side surface is a concave surface, the eighth lens has positive power, and the object side surface and the image side surface of the eighth lens are both convex surfaces; and/or,

The object-side surface and the image-side surface of the ninth lens are both convex surfaces.

A medical endoscope comprises the par-zoom optical adapter as described in any of the above embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the structure of a par-zoom optical adapter in a wide-angle state in some embodiments.

FIG. 2 is a schematic diagram of the structure of a par-zoom optical adapter in a telephoto state in some embodiments.

FIG. 3 is a graph showing a transfer function of a par-zoom optical adapter in a wide-angle state in some embodiments.

FIG. 4 is a graph showing a defocus curve of a par-zoom optical adapter in a wide-angle state in some embodiments.

FIG. 5 is a diagram showing field curvature curves and distortion curves of a par-zoom optical adapter in a wide-angle state in some embodiments.

FIG. 6 is a graph showing a transfer function of a par-zoom optical adapter in a mid-focus state in some embodiments.

FIG. 7 is a graph showing a defocus curve of a par-zoom optical adapter in a mid-focus state in some embodiments.

FIG. 8 is a graph showing field curvature and distortion of a par-zoom optical adapter in a mid-focus state in some embodiments.

FIG. 9 is a graph showing a transfer function of a par-zoom optical adapter in a telephoto state in some embodiments.

FIG. 10 is a graph showing a defocus curve of a par-zoom optical adapter in a telephoto state in some embodiments.

FIG. 11 is a diagram showing a field curvature curve and a distortion curve of a par-zoom optical adapter in a telephoto state in some embodiments.

10. Parfocal optical adapter; L1. first lens; G1. zoom group; L23. first cemented lens group; L2. second lens; L3. third lens; L4. fourth lens; G2. compensation group; L5. fifth lens; L6. sixth lens; L78. second cemented lens group; L7. seventh lens; L8. eighth lens; L9. ninth lens; 11. optical axis; 12. imaging surface; 13. first protective element; 14. second protective element; 15. aperture.

DETAILED DESCRIPTION

In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "on" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

Please refer to FIG. 1 . The present application provides a zoom optical adapter 10, which can be applied to medical devices, such as hard-tube medical endoscopes. The medical endoscope may include a camera and an endoscope mirror. The zoom optical adapter 10 may be arranged between the endoscope mirror and the camera to adjust the light collected by the endoscope mirror and project it onto the camera, so as to achieve optical path connection between the camera and the endoscope mirror. In some embodiments, the zoom optical adapter 10 includes a front fixed group, a zoom group G1, a compensation group G2, and a rear fixed group in sequence from the object side to the image side along the optical axis 11. The front fixed group includes a first lens L1, and the zoom group G1 includes a second lens L2, a third lens L3, and a fourth lens L4 in sequence from the object side to the image side along the optical axis 11. The second lens L2 and the third lens L3 are cemented to form a first cemented lens group L23 with positive optical power, and the fourth lens L4 has positive optical power. The compensation group G2 includes a fifth lens L5, a sixth lens L6, a seventh lens L7 and an eighth lens L8 in order from the object side to the image side along the optical axis 11. The seventh lens L7 and the eighth lens L8 are cemented together to form a second cemented lens group L78. The rear fixed group includes a ninth lens L9.

In some embodiments, the zoom group G1 and the compensation group G2 can move along the optical axis 11 between the first lens L1 and the rear fixed group to achieve the optical zoom function of the par-zoom optical adapter 10. In some embodiments, the par-zoom optical adapter 10 further includes an imaging surface 12 disposed on the image side of the ninth lens L9, and the incident light can be projected onto the imaging surface 12 after adjustment of each lens in the par-zoom optical adapter 10.

In some embodiments, the par-zoom optical adapter 10 may further include a first protective element 13 disposed on the object side of the first lens L1 and a second protective element 14 disposed on the image side of the ninth lens L9. The first protective element 13 and the second protective element 14 may both be glass plates, and the first protective element 13 and the second protective element 14 are used to protect the lenses in the par-zoom optical adapter 10 and the camera or other optical structures disposed on the image side.

Further, in some embodiments, the first lens L1 has negative power, and the image side surface of the first lens L1 is concave. The fourth lens L4 has positive power, and the first cemented lens group L23 has positive power. The fifth lens L5 has power, the sixth lens L6 has negative power, and the second cemented lens group L78 has positive power. The ninth lens L9 has positive power.

The above-mentioned par-zoom optical adapter 10 is provided with a variable magnification group G1 and a compensation group G2 that move along the optical axis 11. While realizing the optical zoom function, the compensation group G2 can also compensate for the position change of the imaging surface 12 on the optical axis 11, thereby maintaining the position of the imaging surface 12 on the optical axis 11 relatively stable, which is conducive to realizing the par-zoom function, so that the par-zoom optical adapter 10 maintains good imaging quality during the zooming process. At the same time, the first lens L1 and the ninth lens L9 are provided. The first lens L1 with negative optical power can collect light well and expand the aperture, and the ninth lens L9 with positive optical power can effectively converge the light to the imaging surface 12, thereby improving the compatibility of the par-zoom optical adapter 10 with the image side optical structure, which is conducive to realizing the effects of large aperture and high resolution, and is conducive to improving the accuracy of diagnosis and treatment. In the present application, the description of the par-zoom optical adapter 10 being able to achieve the par-zoom function can be understood as that during the optical zoom process, the position of the imaging surface 12 of the par-zoom optical adapter 10 on the optical axis 11 is relatively stable, for example, the position of the imaging surface 12 on the optical axis 11 remains stationary or the offset amplitude is sufficiently small.

Among them, the negative focal power of the first lens L1, the positive focal power of the zoom group G1, the negative focal power of the compensation group G2, and the positive focal power of the ninth lens L9 cooperate to make the light smoothly transition in the par-zoom optical adapter 10, which is conducive to suppressing the generation of aberrations, reducing aberration sensitivity, and improving imaging quality. The negative focal power of the first lens L1, combined with the design that the image side surface of the first lens L1 is a concave surface, is conducive to collecting light and diverging the light to the image side, increasing the amount of light entering and the aperture of the par-zoom optical adapter 10, and improving the imaging brightness and imaging quality. The positive focal power of the first cemented lens group L23 and the positive focal power of the fourth lens L4 in the zoom group G1 can smoothly converge and transition the light toward the image side, which is beneficial to shorten the total length of the par-zoom optical adapter 10 and also beneficial to make the light transition smoother, thereby effectively suppressing the distortion and other aberrations of the edge field of view. In combination with the focal power and surface design of the first lens L1 and the fifth lens L5, it is beneficial to make the light fill the pupil and realize the large aperture design, so that the par-zoom optical adapter 10 can meet the relative illumination requirements, improve the edge field of view illumination, and improve the imaging quality of the par-zoom optical adapter 10 in a weak light environment. The negative focal power of the sixth lens L6 and the positive focal power of the second cemented lens group L78, in combination with the focal power design of the fifth lens L5 and the zoom group G1, can smoothly transition the light, correct the aberration, reduce the aberration sensitivity of the par-zoom optical adapter 10, and improve the imaging quality. At the same time, it can also reasonably diverge the light to the image side and expand the aperture of the par-zoom optical adapter 10. The ninth lens L9 has positive refractive power, and can converge the light rays reasonably transitioned from each lens on the object side toward the imaging surface 12, thereby improving the compatibility of the light rays with the optical structure on the image side.

Therefore, the above-mentioned full-zoom optical adapter 10 can achieve the effects of large aperture, miniaturization, high resolution and good imaging quality.

In some embodiments, the second lens L2 has positive power, the object side surface of the second lens L2 is convex, and the image side surface is concave, the third lens L3 has positive power, and both the object side surface and the image side surface of the third lens L3 are convex. The seventh lens L7 has negative power, the object side surface of the seventh lens L7 is a plane, and the image side surface is concave, the eighth lens L8 has positive power, and both the object side surface and the image side surface of the eighth lens L8 are convex. The design of bonding the second lens L2 and the third lens L3, and bonding the seventh lens L7 and the eighth lens L8 is conducive to reasonable deflection of light, while correcting aberrations such as chromatic aberration and distortion of the zoom optical adapter 10, and improving the imaging quality.

It should be noted that, in the present application, the description of the bonding of two lenses can be understood as describing the limitation of the relative positions of the two lenses. For example, the image side surface of one lens matches and abuts against the object side surface of the other lens. At this time, it can be considered that the relative surfaces of the two lenses overlap, and the two lenses are relatively fixed, but it cannot be understood as a limitation of the bonding process of the two lenses. The two lenses are bonded by optical glue, or abutted and relatively fixed by other means such as structural parts, which are all within the scope of the bonding of the two lenses described in the present application. In some embodiments, the lenses in the par-zoom optical adapter 10 are coaxial, and the common axis of the lenses is the optical axis 11 of the system. In the present application, the description of the object side surface of a lens can be understood as the surface of the lens facing away from the imaging surface 12, and the description of the image side surface of a lens can be understood as the surface of the lens facing the imaging surface 12.

In some embodiments, the par-zoom optical adapter 10 further includes an aperture 15, which is disposed between the fifth lens L5 and the sixth lens L6, and can move synchronously with the compensation group G2 on the optical axis 11. Disposing the aperture 15 between the fifth lens L5 and the sixth lens L6, in conjunction with the focal length design of each lens of the zoom group G1 and the compensation group G2, is conducive to achieving a large aperture design.

In some embodiments, the object side surface of the first lens L1 is a concave surface, which is helpful to improve the ability of the first lens L1 to collect light in combination with the focal power and image side surface design of the first lens L1, thereby facilitating the increase of the aperture. The object side surface of the fourth lens L4 is a convex surface, and the image side surface is a plane surface, which is not only conducive to the smooth transition of light, but also conducive to the structural design of the compensation group G2. The fifth lens L5 has a negative focal power, and the object side surface and image side surface of the fifth lens L5 are both concave surfaces, and the object side surface and image side surface of the sixth lens L6 are both concave surfaces, which are helpful for light to pass through the aperture 15, improve the utilization efficiency of light, and realize a large aperture design in combination with the negative focal power of the sixth lens L6. The object side surface and image side surface of the ninth lens L9 are both convex surfaces, which can effectively converge light to the imaging surface 12, which is helpful to adjust the incident angle of light on the imaging surface 12, improve the adaptability of light to the optical structure of the image side, thereby improving the resolution and imaging quality of the par-zoom optical adapter 10.

In some embodiments, the object side surface and the image side surface of each lens in the par-zoom optical adapter 10 are both spherical surfaces, and the material of each lens is glass, which is conducive to the miniaturization design of the par-zoom optical adapter 10.

As shown in combination with FIG1 and FIG2, FIG1 is a schematic structural diagram of the par-zoom optical adapter 10 in a wide-angle state in some embodiments, and FIG2 is a schematic structural diagram of the par-zoom optical adapter 10 in a telephoto state in some embodiments. It can be seen that the par-zoom optical adapter 10 changes the effective focal length of the zoom optical adapter by moving the variable power group G1 and the compensation group G2 along the optical axis 11 between the first lens L1 and the ninth lens L9, thereby realizing the optical zoom function.

Further, in some embodiments, when the zoom group G1 moves along the optical axis 11 toward the direction close to the first lens L1 and away from the ninth lens L9, and the compensation group G2 moves along the optical axis 11 toward the direction close to the first lens L1 and away from the ninth lens L9, the effective focal length of the par-zoom optical adapter 10 gradually increases. Of course, according to different designs of each lens, there can be other corresponding relationships between the change rule of the effective focal length of the par-zoom optical adapter 10 and the movement rule of the zoom group G1 and the compensation group G2 along the optical axis 11. In other embodiments, when changing between some of the focal length states, only one of the zoom group G1 and the compensation group G2 can move along the optical axis 11. When the zoom group G1 moves along the optical axis 11, the first cemented lens group L23 and the fourth lens L4 move synchronously along the optical axis 11. When the compensation group G2 moves along the optical axis 11, the fifth lens L5, the aperture 15, the sixth lens L6 and the second cemented lens group L78 move synchronously along the optical axis 11.

In some embodiments, the first lens L1 can move along the optical axis 11 on the object side of the zoom group G1 to achieve an optical focusing function. In this way, the zoom and focus functions of the par-zoom optical adapter 10 do not interfere with each other, and both the focus function and the par-zoom function can be achieved, thereby improving the applicable scope of the par-zoom optical adapter 10, so that the par-zoom optical adapter 10 can adapt to endoscopes of different focal lengths and obtain good imaging quality.

In some embodiments, when the par-zoom optical adapter 10 is in the wide-angle state, the effective focal length of the par-zoom optical adapter 10 is 17 mm, and when the par-zoom optical adapter 10 is in the telephoto state, the effective focal length of the par-zoom optical adapter 10 is 31 mm. The par-zoom optical adapter 10 may further include a medium-focus state between the wide-angle state and the telephoto state, and when the par-zoom optical adapter 10 is in the medium-focus state, the effective focal length of the par-zoom optical adapter 10 may be 26 mm. Of course, the wide-angle state, the medium-focus state, and the telephoto state are only examples of three focal length states of the par-zoom optical adapter 10. Depending on the positions of the variable magnification group G1 and the compensation group G2 on the optical axis 11, the effective focal length of the par-zoom optical adapter 10 may be any value between the wide-angle state and the telephoto state, for example, the effective focal length of the par-zoom optical adapter 10 may be any value between 17 mm and 31 mm.

In some embodiments, the par-zoom optical adapter 10 satisfies the conditional formula: 0.2≤(D1/TTL)≤0.4; 0.1≤(D2/TTL)≤0.2; wherein D1 is the stroke of the zoom group G1 on the optical axis 11, that is, the maximum moving distance of the zoom group G1 on the optical axis 11, D2 is the stroke of the compensation group G2 on the optical axis 11, and TTL is the total length of the par-zoom optical adapter 10. When the par-zoom optical adapter 10 is provided with a first protection element 13 and a second protection element 14, the total length of the par-zoom optical adapter 10 may be the distance from the object side surface of the first protection element 13 to the image side surface of the second protection element 14 on the optical axis 11. For example, D1/TTL may be 0.2, 0.3 or 0.4, and D2/TTL may be 0.1 or 0.2. In some embodiments, D1 may be the distance from the object side of the second lens L2 in the wide-angle state to the object side of the second lens L2 in the telephoto state on the optical axis 11, and D2 may be the distance from the object side of the fifth lens L5 in the wide-angle state to the object side of the fifth lens L5 in the telephoto state on the optical axis 11. When the above conditional expressions are met, the movement stroke of the zoom group G1 and the compensation group G2 on the optical axis 11 can be reasonably configured, so that the zoom group G1 and the compensation group G2 can cooperate well, maintain good imaging quality while realizing the optical zoom function, and realize the full zoom function. In addition, in conjunction with the optical power design of each lens, it is also beneficial to realize a large range of zoom with a smaller stroke, which is beneficial to improve the zoom response speed and zoom range.

In some embodiments, the par-zoom optical adapter 10 satisfies the conditional formula: 22≤|F1/CT1|≤28; wherein F1 is the effective focal length of the first lens L1, and CT1 is the thickness of the first lens L1 on the optical axis 11. For example, |F1/CT1| can be 22, 23, 24, 25, 26, 27 or 28. When the above conditional formula is satisfied, the ratio of the effective focal length and the center thickness of the first lens L1 can be reasonably configured, so that the first lens L1 has sufficient negative focal power to collect incident light, which is conducive to realizing a large aperture design. At the same time, the center thickness of the first lens L1 will not be too large, which is conducive to shortening the total length of the par-zoom optical adapter 10. In addition, the surface of the first lens L1 will not be too curved, which is conducive to the manufacturing and molding of the first lens L1.

In some embodiments, the par-zoom optical adapter 10 satisfies the conditional formula: 5≤F23/CT23≤7; wherein F23 is the effective focal length of the first cemented lens group L23, i.e., the combined focal length of the second lens L2 and the third lens L3, and CT23 is the thickness of the first cemented lens group L23 on the optical axis 11, i.e., the distance from the object side surface of the second lens L2 to the image side surface of the third lens L3 on the optical axis 11. For example, F23/CT23 can be 5, 5.2, 5.4, 5.5, 5.8, 6, 6.3, 6.7, 6.8 or 7. When the above conditional formula is satisfied, the ratio of the effective focal length and the center thickness of the first cemented lens group L23 can be reasonably configured, which is conducive to reasonably deflecting the light collected by the first lens L1 and suppressing the generation of aberrations. It is also conducive to shortening the size of the first cemented lens group L23 on the optical axis 11, which is conducive to the miniaturization design of the par-zoom optical adapter 10.

In some embodiments, the parfocal optical adapter 10 satisfies the conditional formula: 0.8≤F4/F23≤1.2; wherein F4 is the effective focal length of the fourth lens L4, and F23 is the effective focal length of the first cemented lens group L23. For example, F4/F23 can be 0.8, 0.9, 1.0, 1.1 or 1.2. When the above conditional formula is satisfied, the ratio of the effective focal lengths of the fourth lens L4 and the first cemented lens group L23 can be reasonably configured, which is conducive to smooth transition of light and reducing the degree of bending of light, thereby helping to reduce aberration sensitivity, improve imaging quality, and prevent the surface of the lens from being too curved, thereby reducing the difficulty of lens design and improving molding yield, and also helping to achieve large aperture design.

In some embodiments, the par-zoom optical adapter 10 satisfies the conditional formula: 10≤|F5/CT5|≤11; wherein F5 is the effective focal length of the fifth lens L5, and CT5 is the thickness of the fifth lens L5 on the optical axis 11. For example, |F5/CT5| can be 10, 10.3, 10.5, 10.6, 10.8 or 11. When the above conditional formula is satisfied, the ratio of the effective focal length and the center thickness of the fifth lens L5 can be reasonably configured, so that the negative power of the fifth lens L5 can effectively diverge the light emitted from the zoom group G1 to the aperture 15, which is conducive to realizing a large aperture design, and is also conducive to preventing the surface of the fifth lens L5 from being excessively curved, reducing the difficulty of lens design, and improving the molding yield.

In some embodiments, the parfocal optical adapter 10 satisfies the conditional formula: 0.3≤F6/F5≤0.4; wherein F6 is the effective focal length of the sixth lens L6, and F5 is the effective focal length of the fifth lens L5. For example, F6/F5 can be 0.3 or 0.4. When the above conditional formula is satisfied, the ratio of the effective focal lengths of the sixth lens L6 and the fifth lens L5 can be reasonably configured, thereby reasonably configuring the focal power distribution on both sides of the aperture 15, so that light can effectively pass through the aperture 15, realizing a large aperture design, and is conducive to suppressing the aberration of the edge field of view and improving the imaging quality.

In some embodiments, the par-zoom optical adapter 10 satisfies the conditional formula: 0.5≤|F6/F78|≤0.6; wherein F6 is the effective focal length of the sixth lens L6, and F78 is the effective focal length of the second cemented lens group L78. For example, |F6/F78| can be 0.5 or 0.6. When the above conditional formula is satisfied, the ratio of the effective focal lengths of the sixth lens L6 and the second cemented lens group L78 can be reasonably configured, which is conducive to reasonably deflecting the divergent light of the sixth lens L6, correcting various aberrations while realizing a large aperture design, and improving the imaging quality of the par-zoom optical adapter 10.

In some embodiments, the par-zoom optical adapter 10 satisfies the conditional formula: 10.5≤F9/CT9≤11.5; wherein F9 is the effective focal length of the ninth lens L9, and CT9 is the thickness of the ninth lens L9 on the optical axis 11. For example, F9/CT9 can be 10.5, 10.7, 10.8, 11, 11.2, or 11.5. When the above conditional formula is satisfied, the ratio of the effective focal length and the center thickness of the ninth lens L9 can be reasonably configured, so that the ninth lens L9 can reasonably transfer the light to the imaging surface 12, which is beneficial to suppress aberrations, and realize a large aperture characteristic while reducing ghost images, which is beneficial to improve the relative illumination of the par-zoom optical adapter 10, improve the illumination of the edge field of view, thereby improving the imaging quality of the par-zoom optical adapter 10 in a weak light environment, and also beneficial to improve the matching of the light and the optical structure on the image side, thereby improving the imaging quality.

In some embodiments, the focal length of the par-zoom optical adapter 10 ranges from 17 mm to 31 mm. In each focal length state, the aperture number of the par-zoom optical adapter 10 ranges from 4.0 to 4.2, and the field of view ranges from 11° to 20°. The par-zoom optical adapter 10 has a sufficiently large zoom range, which can improve the applicability of the par-zoom optical adapter 10, and can have a large aperture effect and good imaging quality in different focal length states.

Further, in some embodiments, the aperture number FNO, effective focal length f, total length TTL, maximum field angle FOV, half image height IMH, distance T1 from the image side surface of the first lens L1 to the object side surface of the second lens L2 on the optical axis 11, distance T2 from the image side surface of the fourth lens L4 to the object side surface of the fifth lens L5 on the optical axis 11, and distance T3 from the image side surface of the eighth lens L8 to the object side surface of the ninth lens L9 on the optical axis 11 of the par-zoom optical adapter 10 in the wide-angle state, the medium-focus state, and the telephoto state are given in the following Table 1. When the following data are met and the focal length and surface configuration of each lens are matched, the par-zoom optical adapter 10 can achieve a large aperture design, a miniaturized design, a high resolution, and good imaging quality.

Table 1

Please refer to 1, FIG. 3-FIG. 11, FIG. 3 is a transfer function (MTF) curve diagram of the par-zoom optical adapter 10 in a wide-angle state in some embodiments, FIG. 4 is a defocus curve diagram of the par-zoom optical adapter 10 in a wide-angle state in some embodiments, FIG. 5 is a field curvature curve diagram and a distortion curve diagram of the par-zoom optical adapter 10 in a wide-angle state in some embodiments, FIG. 6 is a transfer function curve diagram of the par-zoom optical adapter 10 in a medium-focus state in some embodiments, FIG. 7 is a defocus curve diagram of the par-zoom optical adapter 10 in a medium-focus state in some embodiments, FIG. 8 is a field curvature curve diagram and a distortion curve diagram of the par-zoom optical adapter 10 in a medium-focus state in some embodiments, FIG. 9 is a transfer function curve diagram of the par-zoom optical adapter 10 in a telephoto state in some embodiments, FIG. 10 is a defocus curve diagram of the par-zoom optical adapter 10 in a telephoto state in some embodiments, and FIG. 11 is a field curvature curve diagram and a distortion curve diagram of the par-zoom optical adapter 10 in a telephoto state in some embodiments. It can be seen from FIGS. 3 to 11 that, under different focal lengths, when the resolution of the par-zoom optical adapter 10 satisfies 200lp/mm, the MTF value of the central field of view is greater than 0.3, and the diffuse spots in the central field of view point diagram of the par-zoom optical adapter 10 are smaller than the Airy disk. The field curvature, distortion and other aberrations of the par-zoom optical adapter 10 are effectively corrected, and the par-zoom optical adapter 10 can have high resolution and good imaging quality under different focal lengths.

In some embodiments, the par-zoom optical adapter 10 satisfies the data in Table 2 below. The effects that can be obtained by satisfying the following data can be obtained from the above description.

Table 2

In some embodiments, the present application also provides a medical endoscope, including a fixing part and a zoom optical adapter 10 as described in any of the above embodiments, and the zoom optical adapter 10 is arranged on the fixing part. The zoom optical adapter 10 can be used as an optical adapter of the medical endoscope, and the fixing part can be a mechanical structure supporting the zoom optical adapter 10. The medical endoscope can also include a camera and an endoscope mirror. The zoom optical adapter 10 can be arranged between the camera and the endoscope mirror to adjust the image collected by the endoscope mirror and project it onto the camera, thereby improving the imaging quality of the medical endoscope. The above-mentioned zoom optical adapter 10 is used in the medical endoscope. The zoom optical adapter 10 has the effects of large aperture, miniaturization, good imaging quality, etc., and has a sufficient zoom range, which is conducive to the assembly of the zoom optical adapter 10 in the medical endoscope, and is conducive to reducing the volume of the medical endoscope, improving the imaging quality of the medical endoscope, thereby helping to improve the scope of application and optical performance of the medical endoscope, and helping to improve the accuracy of diagnosis and treatment.

The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims (10)

1. A zoom optical adapter, characterized in that it comprises, in order from the object side to the image side along the optical axis: A first lens having negative optical power, wherein the image side surface of the first lens is a concave surface; A zoom group with positive power, the zoom group including a second lens, a third lens and a fourth lens with positive power in sequence from the object side to the image side along the optical axis, the second lens and the third lens being cemented together to form a first cemented lens group with positive power; A compensation group with negative optical power, the compensation group including, from the object side to the image side along the optical axis, a fifth lens, a sixth lens with negative optical power, a seventh lens and an eighth lens, the seventh lens and the eighth lens being cemented together to form a second cemented lens group with positive optical power; a ninth lens having positive refractive power; The variable power group and the compensation group can move along the optical axis between the first lens and the ninth lens to achieve an optical zoom function. 2. The par-zoom optical adapter according to claim 1, wherein the par-zoom optical adapter satisfies the following conditional formula: 0.2≤(D1/TTL)≤0.4; 0.1≤(D2/TTL)≤0.2; Wherein, D1 is the stroke of the zoom group on the optical axis, D2 is the stroke of the compensation group on the optical axis, and TTL is the total length of the par-zoom optical adapter. 3. The par-zoom optical adapter according to claim 1, wherein the par-zoom optical adapter satisfies the following conditional formula: 22≤|F1/CT1|≤28; Wherein, F1 is the effective focal length of the first lens, and CT1 is the thickness of the first lens on the optical axis. 4. The par-zoom optical adapter according to claim 1, wherein the par-zoom optical adapter satisfies the following conditional formula: 5≤F23/CT23≤7; Wherein, F23 is the effective focal length of the first cemented lens group, and CT23 is the thickness of the first cemented lens group on the optical axis. 5. The par-zoom optical adapter according to claim 1, wherein the par-zoom optical adapter satisfies the following conditional formula: 0.8≤F4/F23≤1.2; Among them, F4 is the effective focal length of the fourth lens, and F23 is the effective focal length of the first cemented lens group. 6. The par-zoom optical adapter according to claim 1, wherein the par-zoom optical adapter satisfies the following conditional formula: 10≤|F5/CT5|≤11; and/or, 10.5≤F9/CT9≤11.5; Among them, F5 is the effective focal length of the fifth lens, CT5 is the thickness of the fifth lens on the optical axis, F9 is the effective focal length of the ninth lens, and CT9 is the thickness of the ninth lens on the optical axis. 7. The par-zoom optical adapter according to claim 1, wherein the par-zoom optical adapter satisfies the following conditional formula: 0.3≤F6/F5≤0.4; and/or, 0.5≤|F6/F78|≤0.6; Among them, F6 is the effective focal length of the sixth lens, F5 is the effective focal length of the fifth lens, and F78 is the effective focal length of the second cemented lens group. 8. The par-zoom optical adapter according to claim 1, wherein the first lens can move along the optical axis on the object side of the zoom group to achieve an optical focusing function; And/or, the par-zoom optical adapter further comprises an aperture stop, wherein the aperture stop is disposed between the fifth lens and the sixth lens, and the aperture stop can be synchronously moved along the optical axis with the compensation group. 9. The parfocal optical adapter according to claim 1, wherein the object side surface of the first lens is a concave surface; and/or, The second lens has positive refractive power, the object side surface of the second lens is convex, and the image side surface is concave, the third lens has positive refractive power, and the object side surface and the image side surface of the third lens are both convex; and/or, The object side surface of the fourth lens is a convex surface, and the image side surface is a flat surface; and/or, The fifth lens has negative optical power, and both the object side surface and the image side surface of the fifth lens are concave surfaces; and/or, The object side surface and the image side surface of the sixth lens are both concave surfaces; and/or, The seventh lens has negative power, the object side surface of the seventh lens is a plane, and the image side surface is a concave surface, the eighth lens has positive power, and the object side surface and the image side surface of the eighth lens are both convex surfaces; and/or, The object-side surface and the image-side surface of the ninth lens are both convex surfaces. 10. A medical endoscope, characterized by comprising the par-zoom optical adapter according to any one of claims 1 to 9.