Five-gluing endoscope objective lens optical system

Abstract

The utility model discloses a five-gluing endoscope objective lens optical system which is composed of a first optical assembly with negative focal power and a second optical assembly with positive focal power, wherein the first optical assembly and the second optical assembly are sequentially arranged from the object side. The first optical assembly is composed of protective glass, a first lens, a viewing direction prism interval and a second lens which are sequentially arranged from the object space to the image space along the main optical axis. The second optical assembly is a rod-shaped lens of a biconvex structure, the rod-shaped lens is formed by sequentially gluing a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged from the object space to the image space along the main optical axis, the third lens, the fourth lens and the sixth lens are lenses with negative focal power, and the seventh lens is a lens with negative focal power. And the fifth lens and the seventh lens are lenses with positive focal power. According to the utility model, the effect of enough spacing for configuring the field-of-view steering prism is ensured, and the device has the advantages of small size, easy installation, high image quality and the like.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of medical endoscope, specifically, the utility model relates to a five glue endoscope objective optical system. BACKGROUND

[0002] The endoscope objective optical system is the core of the endoscope imaging system, is used for obtaining high definition image, helps the doctor to observe the condition inside the human body. With the deepening of the research on medical instruments, the design of endoscope has become more and more mature, and endoscope has become the necessary surgical equipment in hospital. And a clear endoscope objective is the primary guarantee of the imaging quality of the whole endoscope optical system. The design of endoscope objective optical system needs to ensure clear imaging, and also needs to adapt to narrow space and small size. But the traditional endoscope objective has the problems of small field of view, less light, low resolution, low edge brightness and high cost. And because the traditional endoscope objective optical structure usually contains three components, the structure is dispersed, the light deflection angle is larger, and the problems of inclination and eccentricity are more likely to occur, which can affect the imaging quality. SUMMARY

[0003] In order to solve the above problems existing in the prior art, the utility model provides a five glue endoscope objective optical system, which ensures the effect of sufficient interval for configuring field of view turning prism, has the advantages of small size, easy installation, high image quality and the like, and can be applied to the medical field.

[0004] The utility model discloses a kind of five glue endoscope objective optical systems, by the optical power of negative first optical component G1 and the optical power of positive second optical component G2 configured sequentially from object side,;The first optical component G1 is sequentially arranged by protective glass F1, first lens L1, view direction prism interval P, second lens L2 from object to image along the main optical axis in order;The second optical component G2 is a double convex structure rod lens, which is sequentially glued by third lens L3, fourth lens L4, fifth lens L5, sixth lens L6 and seventh lens L7 sequentially arranged from object to image along the main optical axis, wherein third lens L3, fourth lens L4 and sixth lens L6 are negative power lenses, and fifth lens L5 and seventh lens L7 are positive power lenses.

[0005] A kind of five glue endoscope objective optical system, by the optical power of negative first optical component G1 and the optical power of positive second optical component G2 configured sequentially from object side,;The first optical component G1 is sequentially arranged by protective glass F1, first lens L1, view direction prism interval P, second lens L2 from object to image along the main optical axis in order;The second optical component G2 is a double convex structure rod lens, which is sequentially glued by third lens L3, fourth lens L4, fifth lens L5, sixth lens L6 and seventh lens L7 sequentially arranged from object to image along the main optical axis, wherein third lens L3, fourth lens L4 and sixth lens L6 are negative power lenses, and fifth lens L5 and seventh lens L7 are positive power lenses.

[0006] Further, the first lens L1 is a plano-concave lens, and the second lens L2 is a plano-convex lens.

[0007] Further, the lenses used in the five glue endoscope objective optical system are all spherical mirrors, and each lens has a matching optical parameter.

[0008] Furthermore, the optical parameters of the five-ply cemented endoscope objective lens optical system satisfy the following conditional equation:

[0009] 2.4 ≤ d1 / f ≤ 4.2

[0010] 0.21≤f² / f≤0.35

[0011] 4.2≤r 31 / r 72 ≤5.4

[0012] -0.1≤f 01 / f≤-0.01

[0013] 0.04≤f1 / f≤0.096

[0014] 0.4≤d1 / d2≤0.8

[0015] 0.03≤I h / f≤0.05

[0016] 2≤L≤3

[0017]

[0018] In the formula, d1 is the air equivalent length from the image-side surface of the first lens L1 to the aperture surface; f is the focal length of the entire endoscopic objective optical system; f2 is the focal length of the second optical component G2; r 31 r is the radius of curvature of the object-side surface of the second optical component G2; 72 f is the radius of curvature of the image-side surface of the second optical component G2; 01 f1 is the focal length of the first lens L1; f2 is the focal length of the first optical component G1; d1 is the air equivalent length from the image side of the first lens L1 to the aperture plane, and d2 is the air equivalent length from the aperture plane to the image plane; I h L is the image height of the endoscope objective optical system; L is the working distance of the endoscope objective optical system. The optical power of the second optical component G2.

[0019] Furthermore, the first optical component G1 includes an aperture stop, which is a seventh surface.

[0020] This utility model has the following advantages:

[0021] This invention replaces two optical components in a traditional endoscope objective lens optical system with a second optical component, improving the fit between lenses and reducing the difficulty of manufacturing and adjustment. Compared with the traditional endoscope objective lens optical system, it has a simpler structure, reduces manufacturing and adjustment errors, and improves the imaging quality of the endoscope. Attached Figure Description

[0022] Figure 1 A structure schematic view of a five-gluing endoscope objective optical system according to the utility model embodiment 1;

[0023] Figure 2 A point array diagram of each field of view of an image surface of a five-gluing endoscope objective optical system according to the utility model embodiment 1;

[0024] Figure 3 An MTF curve of each field of view of an image surface of a five-gluing endoscope objective optical system according to the utility model embodiment 1;

[0025] Figure 4 An axial aberration curve of each wavelength of an image surface of a five-gluing endoscope objective optical system according to the utility model embodiment 1;

[0026] Figure 5 A structure schematic view of a five-gluing endoscope objective optical system according to the utility model embodiment 2;

[0027] Figure 6 A point array diagram of each field of view of an image surface of a five-gluing endoscope objective optical system according to the utility model embodiment 2;

[0028] Figure 7 An MTF curve of each field of view of an image surface of a five-gluing endoscope objective optical system according to the utility model embodiment 2;

[0029] Figure 8 An axial aberration curve of each wavelength of an image surface of a five-gluing endoscope objective optical system according to the utility model embodiment 2.

[0030] In the figure:

[0031] G1-first optical assembly; G2-second optical assembly;

[0032] F1-protective glass; L1-first lens; P-viewing direction prism interval; L2-second lens; L3-third lens; L4-fourth lens; L5-fifth lens; L6-sixth lens; L7-seventh lens. DETAILED DESCRIPTION

[0033] In order to clearly describe the purpose, technical scheme and advantages of the utility model embodiments, the technical scheme in the utility model embodiments will be clearly and completely described below by combining with the drawings and examples.

[0034] The utility model discloses a five gluing endoscope objective optical system, by the first optical assembly G1 (including diaphragm, diaphragm is the seventh face) and the second optical assembly G2 of negative optical power from object side are configured in proper order and the optical power is positive, which is composed of. One optical assembly G1 is by the protective glass F1 of the order of sequence arrangement along the main optical axis from the object to the image, first lens L1, view direction prism interval P, second lens L2 are composed, wherein first lens L1 is flat concave lens, and second lens L2 is flat convex lens. The second optical assembly G2 is a double convex structure's stick lens, and the stick lens is sequentially glued by the third lens L3, fourth lens L4, fifth lens L5, sixth lens L6 and seventh lens L7 of the order of sequence arrangement along the main optical axis from the object to the image, wherein, third lens L3, fourth lens L4 and sixth lens L6 are three different materials' negative optical power lens, and fifth lens L5 and seventh lens L7 are positive optical power lens, and axial chromatic aberration is corrected through the stick lens. The lens used in the five gluing endoscope objective optical system is all spherical mirror, and each lens has the optical parameter of adaptation.

[0035] Further, in the view direction prism interval P for configuring the field of view direction, it is necessary to ensure the case of the corresponding long interval. That is, it is necessary to ensure the relatively long interval for configuring the field of view direction view direction prism relative to the focal length of the optical system. Therefore, it is desirable to satisfy the following conditional expression

[0036] 2.4≤d1 / f≤4.2 (1)

[0037] In the formula, d1 is the air equivalent length from the face of the image side of the first lens L to the diaphragm face; f is the focal length of the entire system of the endoscope objective optical system.

[0038] The conditional expression (1) specifies the ratio of the interval (air equivalent length) for configuring the field of view direction view direction prism P and the focal length of the entire system. When the upper limit value of the conditional expression (1) is exceeded, the interval for configuring the field of view direction view direction prism interval P becomes large, and the refractive power of the first lens L1 is required to be large, resulting in the imaging quality. When the lower limit value of the conditional expression (1) is exceeded, the interval for configuring the field of view direction view direction prism P becomes small, and it is difficult to meet the requirement for miniaturization of the medical endoscope.

[0039] Further, if the refractive power of the second optical assembly G2 set is inappropriate, the spherical aberration and the image surface curvature become large, and the imaging quality is easily affected. Therefore, it is desirable to satisfy the following conditional expression:

[0040] 0.21≤f2 / f≤0.35 (2)

[0041] In the formula, f is the focal length of the entire system of the endoscope objective optical system; f2 is the focal length of the second optical assembly G2.

[0042] When the upper limit value of conditional expression (2) is exceeded, the correction for the curvature of the image surface is excessive and is not desirable. When the lower limit value of conditional expression (2) is fallen below, the correction for the curvature of the image surface is insufficient and is not desirable, either.

[0043] Further, the second optical assembly G2 prevents the ray height of the lens near the image surface from becoming high and the lens from becoming large in diameter because it ensures the height and the exit angle for imaging, and thus maintains an appropriate optical power and requires correction of spherical aberration and coma. Therefore, it is desirable to satisfy the following conditional expression:

[0044] 4.2 < r 31 / r 72 ≤ 5.4 (3)

[0045] In the expression, r 31 is the radius of curvature of the surface on the object side of the second optical assembly G2; and r 72 is the radius of curvature of the surface on the image side of the second optical assembly G2.

[0046] In order to obtain a small and high-image-quality oblique-viewing endoscope, it is necessary to appropriately set the focal length of the first lens L1 and the first optical assembly G1 to maintain a balance between the lens diameter and the optical performance. Therefore, it is desirable to satisfy the following conditional expression:

[0047] -0.1 < f 01 / f < -0.01 (4)

[0048] 0.04 < f1 / f < 0.096 (5)

[0049] In the expression, f 01 is the focal length of the first lens L1; f1 is the focal length of the first optical assembly G1; and f is the focal length of the entire system of the endoscope objective optical system.

[0050] Further, in order to both ensure that the turning prism P has a longer interval for configuring the view angle and control the total length of the endoscope, it is necessary to satisfy the following conditional expression:

[0051] 0.4 < d1 / d2 < 0.8 (6)

[0052] In the expression, d1 is the air equivalent length from the image-side surface of the first lens L1 to the stop surface, and d2 is the air equivalent length from the stop surface to the image surface.

[0053] Further, if the height and the imaging distance of the objective imaging are not appropriate, it can be difficult to find a suitable rod lens to fit therewith, and thus in order to fit a small-diameter image-forming system, it is necessary to satisfy the following conditional expression:

[0054] 0.03 < I hf≤0.05 (7)

[0055] 2≤L≤3 (8)

[0056] In the formula, f is the focal length of the endoscope objective optical system; I h is the image height of the endoscope objective optical system; and L is the working distance of the endoscope objective optical system.

[0057] Further, the second optical assembly G2 is a rod-shaped cemented lens with a double-convex structure, which is formed by cementing in sequence a negative-power lens of three different materials and a positive-power lens of two different materials. The overall power of the second optical system satisfies the following conditional formula:

[0058]

[0059] In the formula, is the power of the second optical assembly.

[0060] The second optical system G2 is a five-cemented double-convex lens, which replaces two optical assemblies of a conventional endoscope objective optical system with one optical assembly, thereby improving the matching degree between lenses and reducing the difficulty of processing and adjustment.

[0061] Further, the utility model discloses a small-size large-view-angle endoscope objective optical system which can be widely applied in endoscopes, and a plano-convex lens L1 is arranged at the position closest to the object side of the first optical assembly G1 to ensure negative refractive power. A field-of-view direction prism interval P is arranged at the image side of the plano-convex lens L1, and oblique observation can be performed. In addition, a field-of-view direction prism is arranged at the image side of the second optical assembly G2, and the field-of-view direction prism can be expanded to the image side of the second optical assembly G2. Figure 1 In the formula, the field-of-view direction prism is drawn as a field-of-view direction prism interval P (parallel plane plate) to represent the drawing after the field-of-view direction prism is expanded.

[0062] Further, the protective package F1 is made of sapphire.

[0063] Example 1

[0064] As Figure 1As shown in FIG. 2, the field turning prism interval P is shown as a field turning prism expanded. Thus, the field turning prism interval P is illustrated as a parallel flat plate having an optical path length equivalent to a prism. This embodiment is a five cemented endoscope objective optical system composed of a first optical assembly Gl of negative refractive power, a stop S, and a second optical assembly G2 of positive refractive power arranged in order from the object side. The first optical assembly Gl is composed of a protective glass Fl, a plano-concave lens LI, a field turning prism interval P, and a plano-convex lens L2 arranged in order from the object side to the image side along the main optical axis. The second optical assembly G2 is a double-convex rod lens composed of a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7 cemented in order from the object side to the image side along the main optical axis, wherein the third lens L3, the fourth lens L4, and the sixth lens L6 are negative power lenses of three different materials, and the fifth lens L5 and the seventh lens L7 are positive power lenses. All the lenses in this optical system are spherical.

[0065] As shown in FIG. 2, Figure 4 The image quality related parameters of this embodiment are shown in FIG. 2. The mtf is close to the diffraction limit and is achromatic, the full field of view is 80°, the image height is 0.6, and the Fno (aperture value) is 7. The stop is the seventh surface, the first and second surfaces are protective glasses, and the material is sapphire. The radii of curvature of all the lenses in the second optical assembly are different, so that the problem of decentration can be reduced when the system is assembled.

[0066] Embodiment 2

[0067] As shown in FIG. 2, Figure 5 The field turning prism interval P is a 30° field turning prism. This embodiment is a five cemented endoscope objective optical system composed of a first optical assembly Gl of negative refractive power, a stop S, and a second optical assembly G2 of positive refractive power arranged in order from the object side. The first optical assembly Gl is composed of a protective glass Fl, a plano-concave lens LI, a field turning prism interval P, and a plano-convex lens L2 arranged in order from the object side to the image side along the main optical axis. The second optical assembly G2 is a double-convex rod lens composed of a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7 cemented in order from the object side to the image side along the main optical axis, wherein the third lens L3, the fourth lens L4, and the sixth lens L6 are negative power lenses of three different materials, and the fifth lens L5 and the seventh lens L7 are positive power lenses. All the lenses used are spherical.

[0068] As shown in FIG. 2, Figure 6 to Figure 8The image quality related parameters of the embodiment are shown, the mtf is close to the diffraction limit and has no chromatic aberration, the full field of view is 70°, the image height is 0.6, the Fno (aperture value) is 7.01593, and the focal length is 0.94481. When the full field of view is 70°, the five-cemented lens structure can harvest better imaging quality while keeping the original advantages.

[0069] The above detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative labor fall within the scope of the claimed application.

[0070] It should be noted that: similar labels and letters represent similar items in the drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0071] The above only represents preferred embodiments of the present application and is not intended to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A five-glued endoscope objective optical system characterized by comprising: The optical system comprises a first optical component G1 with negative focal length and a second optical component G2 with positive focal length arranged in sequence from the object side; the first optical component G1 comprises a protective glass F1, a first lens L1, a view direction prism interval P and a second lens L2 arranged in sequence along the main optical axis from the object side to the image side; the second optical component G2 is a double-convex rod lens which is formed by a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7 arranged in sequence along the main optical axis from the object side to the image side, wherein the third lens L3, the fourth lens L4 and the sixth lens L6 are lenses with negative focal length, and the fifth lens L5 and the seventh lens L7 are lenses with positive focal length.

2. A five-glued endoscope objective optical system according to claim 1, characterized by, The first lens L1 is a plano-concave lens, and the second lens L2 is a plano-convex lens.

3. A five-glued endoscope objective optical system according to claim 1, characterized by, All the lenses used in the five-cemented endoscope objective optical system are spherical lenses, and each lens has matching optical parameters.

4. A five-glued endoscope objective optical system according to claim 1, characterized by, The optical parameters of the five-cemented endoscope objective optical system satisfy the following conditional expressions: 2.4≤d1 / f≤4.2 0.21≤f2 / f≤0.35 4.2≤r 31 / r 72 ≤5.4 -0.1 < f 01 f < -0.01 0.04≤f1 / f≤0.096 0.4≤d1 / d2≤0.8 0.03 < I h f < 0.05 2≤L≤3 wherein d1 is an air equivalent length from an image side surface of the first lens L to a stop surface; f is a focal length of the entire system of the endoscope objective optical system; f2 is a focal length of the second optical assembly G2; r 31 is a radius of curvature of an object side surface of the second optical assembly G2; r 72 is a radius of curvature of an image side surface of the second optical assembly G2; f 01 is a focal length of the first lens L1; f1 is a focal length of the first optical assembly G1; d1 is an air equivalent length from an image side surface of the first lens L1 to a stop surface, d2 is an air equivalent length from a stop surface to an image surface; I h is an image height of the endoscope objective optical system; L is a working distance of the endoscope objective optical system; is a power of the second optical assembly G2.

5. A five-glued endoscope objective optical system according to claim 1, characterized by, The first optical component G1 contains a diaphragm, and the diaphragm is the seventh surface.

Images