Wide-angle endoscope optical system

文档序号：748284 发布日期：2021-04-23 浏览：20次中文

阅读说明：本技术 一种广角内窥镜光学系统 (Wide-angle endoscope optical system ) 是由李璇朱佳巍李宇键叶晓健符致秋于 2021-02-01 设计创作，主要内容包括：本发明提供一种广角内窥镜光学系统。该广角内窥镜光学系统从物侧到像侧依次包括：具有保护作用的蓝宝石平板(SP),具有负光焦度的物侧透镜组(G01),光阑(ST),具有正光焦度的像侧透镜组(G02),芯片保护玻璃(GS)；物侧透镜组(G01)包括具有负光焦度的第一透镜(L1)和具有正光焦度的第二透镜(L2)；像侧透镜组(G02)包括具有正光焦度的第三透镜(L3)和具有负光焦度的第四透镜(L4)；第一透镜(L1)物侧面为平面且透镜组均为正负透镜组合,可以在保证视场角的情况下校正像散和控制畸变。(The invention provides a wide-angle endoscope optical system. The wide-angle endoscope optical system includes, in order from an object side to an image side: a sapphire flat plate (SP) with protection function, an object side lens group (G01) with negative focal power, a diaphragm (ST), an image side lens group (G02) with positive focal power, and chip protection Glass (GS); the object side lens group (G01) includes a first lens (L1) having negative power and a second lens (L2) having positive power; the image side lens group (G02) includes a third lens (L3) having positive power and a fourth lens (L4) having negative power; the first lens (L1) has a plane object side surface and a positive and negative lens combination, and can correct astigmatism and control distortion under the condition of ensuring the field angle.)

1. A wide-angle endoscope optical system comprising, in order from an object side to an image side:

the lens comprises a sapphire flat plate (SP) with a protection function, an object side lens group (G01) with negative focal power, a diaphragm (ST), an image side lens group (G02) with positive focal power, chip protection glass (CG) and an image plane (IMG);

the object side lens group (G01) includes a first lens (L1) having negative power and a second lens (L2) having positive power; the image side lens group (G02) includes a third lens (L3) having positive power and a fourth lens (L4) having negative power;

the wide-angle endoscope optical system satisfies the following conditional expression:

-2.9<(f(a)-f(b))/f<-2.2；

wherein f (a) is the focal length of the object side lens group (G01), f (b) is the focal length of the image side lens group (G02), and f is the focal length of the entire wide-angle endoscope optical system;

the object side surface of the first lens (L1) is a plane, and the image side surface is a concave surface;

the object side surface of the second lens (L2) is convex, and the image side surface is concave;

the object side surface and the image side surface of the third lens (L3) are convex surfaces;

the object side surface and the image side surface of the fourth lens (L4) are both concave surfaces;

the first lens (L1), the second lens (L2), the third lens (L3) and the fourth lens (L4) are all plastic aspheric lenses;

the wide-angle endoscope optical system satisfies the following conditional expressions:

0.2<(D3+D11)/(2*T311)<0.4；

2. The wide-angle endoscope optical system according to claim 1 satisfies the following conditional expressions:

-1.1<f1/f<-0.9；

13.5<f2/f<14；

1<f3/f<1.2；

-1.7<f4/f<-1.6；

3. The wide-angle endoscope optical system according to claim 1 satisfies the following conditional expressions:

1.2<ImgH/f<1.3；

wherein ImgH is the maximum image height of the wide-angle endoscope optical system.

4. The wide-angle endoscope optical system according to claim 1 satisfies the following conditional expressions:

2.4<tan(ω/2)<4.4；

where ω is the angle of view of the wide-angle endoscope optical system.

5. The wide-angle endoscope optical system according to claim 1, satisfying the following relation:

1.7<Obd/TTL<1.8；

6. The wide-angle endoscope optical system according to claim 1, satisfying the following relation:

0<T45-SA4<0.04；

wherein T45 is the distance between the image side surface of the first lens (L1) and the object side surface of the second lens (L2) on the optical axis; SA4 is the distance in the direction parallel to the optical axis from the intersection of the image-side surface of the first lens (L1) and the optical axis to the position of the maximum effective diameter.

7. The wide-angle endoscope optical system according to claim 1, satisfying the following relation:

0.03<T6st/TTL<0.06；

0.01<Tst8/TTL<0.04；

wherein T6ST is the axial distance between the image side surface of the second lens (L2) of the wide-angle endoscope optical system and a fixed diaphragm (ST); tst8 is the on-axis distance from the fixed Stop (ST) of the wide-angle endoscope optical system to the object-side surface of the third lens (L3).

8. The wide-angle endoscope optical system according to claim 1 satisfies the following conditional expressions:

-0.01<T56-T89<0；

-0.2<(T34+T56)-(T89+T1011)<0；

wherein T34 is the central thickness of the first lens (L1) on the optical axis; t56 is the central thickness of the second lens (L2) on the optical axis; t89 is the central thickness of the third lens (L3) on the optical axis; t1011 is the central thickness of the fourth lens (L4) on the optical axis.

9. The wide-angle endoscope optical system according to claim 1 satisfies the following conditional expressions:

1<T45/T68<1.1；

wherein T45 is the distance between the image side surface of the first lens (L1) and the object side surface of the second lens (L2) on the optical axis; the distance between the image side surface of the second lens (L2) and the object side surface of the third lens (L3) on the optical axis.

10. The wide-angle endoscope optical system according to claim 1 satisfies the following conditional expressions:

30<Vd1-Vd2<40；

wherein Vd1 is the abbe number of the first lens (L1); vd2 is the abbe number of the second lens (L2).

11. The wide-angle endoscope optical system according to claim 1, satisfying the following relation:

0<SA5<0.02；

0<SA6<0.02；

SA5 is the distance between the intersection point of the object side surface of the second lens (L2) and the optical axis and the position of the maximum effective diameter of the second lens in the direction parallel to the optical axis; SA6 is the distance between the intersection point of the image side surface of the second lens (L2) and the optical axis and the position of the maximum effective diameter in the direction parallel to the optical axis.

12. The wide-angle endoscope optical system according to claim 1, satisfying the following relation:

2.2<f*tan(ω/2)/ImgH<2.3。

[ technical field ] A method for producing a semiconductor device

The present invention relates to a wide-angle endoscope optical system.

[ background of the invention ]

The endoscope is used as a novel medical detection means, and can help doctors to effectively confirm the lesion area and the lesion degree of patients; with the development and progress of science and technology, the requirements of people on the use of endoscopes are higher and higher, including smaller size, higher imaging quality, wider angle of view and wider working distance, so that not only the experience of a patient using the endoscope can be improved, but also the lesion can be detected more quickly and accurately.

The present invention has been developed to meet such a demand for use.

[ summary of the invention ]

The invention provides an endoscope optical system with a large field angle and a large depth of field in order to meet the existing market demand.

The invention is realized by the following technical scheme:

a wide-angle endoscope optical system comprising, in order from an object side to an image side:

the wide-angle endoscope optical system satisfies the following conditional expressions:

-2.9<(f(a)-f(b))/f<-2.2； (1)

the object side surface of the first lens (L1) is a plane, and the image side surface is a concave surface;

the second lens element (L2) has a convex object-side surface and a concave image-side surface;

the object side surface and the image side surface of the third lens (L3) are convex surfaces;

the object side surface and the image side surface of the fourth lens (L4) are both concave surfaces;

the first lens (L1), the second lens (L2), the third lens (L3) and the fourth lens (L4) are all plastic aspheric lenses;

the wide-angle endoscope optical system satisfies the following conditional expressions:

0.2<(D3+D11)/(2*T311)<0.4； (2)

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

-1.1<f1/f<-0.9； (3)

13.5<f2/f<14； (4)

1<f3/f<1.2； (5)

-1.7<f4/f<-1.6； (6)

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

1.2<ImgH/f<1.3； (7)

wherein ImgH is the maximum image height of the wide-angle endoscope optical system.

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

2.4<tan(ω/2)<4.4； (8)

where ω is the angle of view of the wide-angle endoscope optical system.

The wide-angle endoscope optical system as described above satisfies the following relation:

1.7<Obd/TTL<1.8； (9)

The wide-angle endoscope optical system as described above satisfies the following relation:

0<T45-SA4<0.04； (10)

The wide-angle endoscope optical system as described above satisfies the following relation:

0.03<T6st/TTL<0.06； (11)

0.01<Tst8/TTL<0.04； (12)

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

-0.01<T56-T89<0； (13)

-0.2<(T34+T56)-(T89+T1011)<0； (14)

where T34 is the center thickness of the first lens (L1) on the optical axis. T56 is the central thickness of the second lens (L2) on the optical axis; t89 is the central thickness of the third lens (L3) on the optical axis; t1011 is the central thickness of the fourth lens (L4) on the optical axis.

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

1<T45/T68<1.1； (15)

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

30<Vd1-Vd2<40； (16)

wherein Vd1 is the abbe number of the first lens (L1); vd2 is the abbe number of the second lens (L2).

The wide-angle endoscope optical system as described above satisfies the following relation:

0<SA5<0.02； (17)

0<SA6<0.02； (18)

The wide-angle endoscope optical system as described above satisfies the following relation:

2.2<f*tan(ω/2)/ImgH<2.3； (19)

compared with the prior art, the invention has the following advantages:

the wide-angle endoscope optical system realizes 140-degree wide field angle, can be widely applied to medical endoscopes requiring large field range, and can observe the pathological changes of patients more conveniently and effectively. The wide-angle endoscope optical system is long in depth of field, can achieve detailed observation of pathological changes in a short distance and long-distance work, is suitable for various medical detection environments, reduces sensitivity and assembly difficulty through reasonable optimization control, can achieve high production yield, effectively reduces cost, and has strong market advantages.

[ description of the drawings ]

Fig. 1 is a schematic configuration diagram of a wide-angle endoscope optical system of the present invention.

Fig. 2 is an astigmatism diagram and a distortion diagram of the optical system of the wide-angle endoscope.

Fig. 3 is a vertical axis chromatic aberration diagram of the optical system of the wide-angle endoscope.

[ detailed description ] embodiments

The technical features of the present invention will be described in further detail with reference to the accompanying drawings.

A wide-angle endoscope optical system comprising, in order from an object side to an image side:

the sapphire flat plate has strong scratch resistance and corrosion resistance, and can well play a role in protecting a lens; the object side lens group (G01) includes a first lens (L1) having negative power and a second lens (L2) having positive power; the image side lens group (G02) includes a third lens (L3) having positive power and a second lens (L4) having negative power;

the wide-angle endoscope optical system as described above satisfies the following conditional expressions:

-2.9<(f(a)-f(b))/f<-2.2； (1)

the object side surface of the first lens (L1) is a plane, which is beneficial to ensuring the size of the angle of view, and the image side surface is a concave surface;

the second lens element (L2) has a convex object-side surface and a concave image-side surface;

the object side surface and the image side surface of the third lens (L3) are convex surfaces;

the object side surface and the image side surface of the fourth lens (L4) are both concave surfaces;

the first lens (L1), the second lens (L2), the third lens (L3) and the fourth lens (L4) are all plastic aspheric lenses, so that cost is saved during batch production;

the wide-angle endoscope optical system as described above satisfies the following conditional expressions:

0.2<(D3+D11)/(2*T311)<0.4； (2)

wherein D3 is the effective diameter size of the object side surface of the first lens (L1); d11 is the effective diameter size of the image side surface of the fourth lens (L4); t311 is the distance between the object-side surface of the first lens (L1) and the image-side surface of the fourth lens (L4) on the optical axis. By satisfying the formula (2), the proportion of the integral aperture of the lens to the total length of the lens can be effectively controlled; when the ratio exceeds the upper limit value, the aperture of the lens is larger, and when the ratio exceeds the lower limit value, the total length of the lens is larger, which is not beneficial to the actual installation and use of the lens.

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

-1.1<f1/f<-0.9； (3)

13.5<f2/f<14； (4)

1<f3/f<1.2； (5)

-1.7<f4/f<-1.6； (6)

wherein f1 is the equivalent focal length of the first lens (L1); f2 is the equivalent focal length of the second lens (L2); f3 is the equivalent focal length of the third lens (L3); f4 is the equivalent focal length of the fourth lens (L4); f is the focal length of the whole wide-angle endoscope optical system; the two lens groups are the combination of positive and negative lenses, so that a light path can smoothly pass through the edge of the lens, the turning with a larger angle is avoided, the sensitivity of the lens tolerance in the inch method can be reduced, and the astigmatism correction and the distortion control are facilitated.

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

1.2<ImgH/f<1.3； (7)

wherein ImgH is the maximum image height of the wide-angle endoscope optical system.

The size of the focal length in the formula (7) can be used for restricting the depth of field of the optical system of the wide-angle endoscope, when the ratio is lower than a lower limit value, the depth of field of the system is smaller, and a close view and a long view become worse; when the ratio exceeds the upper limit value, the aperture of the system is smaller, and the illumination of the system is smaller.

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

2.4<tan(ω/2)<4.4； (8)

where ω is the angle of view of the wide-angle endoscope optical system. The formula (8) is used for limiting the size of the field of view of the optical system, and avoiding that the field angle is too small, the object height does not meet the requirement, or the distortion of the optical system is too serious due to too large field angle;

the wide-angle endoscope optical system as described above satisfies the following relation:

1.7<Obd/TTL<1.8； (9)

obd is the optimal imaging object distance of the wide-angle endoscope optical system; TTL is the on-axis distance from the object side surface of the first lens to the imaging surface of the wide-angle endoscope optical system. The above formula (9) is used to limit the depth of field range of the optical system, and the optimal ratio of the object distance to the total lens length exceeds the lower limit, the close range is better than expected, and the long range is worse; when the ratio exceeds the upper limit, the long-range view is better than the expectation, and the short-range view is worse;

the wide-angle endoscope optical system as described above satisfies the following relation:

0<T45-SA4<0.04； (10)

wherein T45 is the distance between the image side surface of the first lens (L1) and the object side surface of the second lens (L2) on the optical axis; SA4 is the distance between the intersection point of the image side surface of the first lens (L1) and the optical axis and the position of the maximum effective diameter in the direction parallel to the optical axis;

when the formula (10) is satisfied, the difference is small, so that curvature of field and astigmatism of the first lens are mainly generated on the image side surface, and the first lens and the second lens can be compensated with each other. And the relative illumination of the optical system is improved on the premise of ensuring a large field angle in the optimization process.

The wide-angle endoscope optical system as described above satisfies the following relation:

0.03<T6st/TTL<0.06； (11)

0.01<Tst8/TTL<0.04； (12)

satisfying the above equations (11) and (12) is advantageous in ensuring the incident angle of the light between the lenses, improving the relative illuminance of the optical system, and making the diaphragm at a more reasonable position is also advantageous in correcting the distortion and astigmatism of the entire optical system.

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

-0.01<T56-T89<0； (13)

-0.2<(T34+T56)-(T89+T1011)<0； (14)

when the formulas (13) and (14) are satisfied, the central thicknesses of the first lens, the second lens and the fourth lens are reasonably distributed, so that the aberration of an optical system is reduced in the optimization process, a good compensation effect is achieved between lenses, and the image quality is improved. And the thickness distribution is relatively uniform, which is beneficial to the processing and injection molding of the lens and the lens assembling process.

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

1<T45/T68<1.1； (15)

when the formula (15) is satisfied, mutual compensation of aberration between lenses is facilitated, the imaging quality of the whole optical system is improved, high-precision assemblability is facilitated to be guaranteed, and control of the incident angle of light and the total length of the whole lens is facilitated.

The wide-angle endoscope optical system as described above satisfies the following conditional expressions:

30<Vd1-Vd2<40； (16)

wherein Vd1 is the abbe number of the first lens (L1); vd2 is the abbe number of the second lens (L2);

when the formula (16) is satisfied, it is helpful to correct chromatic aberration and aberration, and if the difference is too large or too small, the magnification chromatic aberration is large, the picture color is distorted, and color smear occurs.

The wide-angle endoscope optical system as described above satisfies the following relation:

0<SA5<0.02； (17)

0<SA6<0.02； (18)

when the formula (17) and the formula (18) are satisfied, the thickness of the lens is increased very slowly from the optical axis to the maximum effective diameter position, so that the thickness of the whole lens is uniform, the injection molding filling process is smooth, the precision of the lens is improved, the tolerance sensitivity is reduced, and the imaging quality of the whole optical system is improved.

The wide-angle endoscope optical system as described above satisfies the following relation:

2.2<f*tan(ω/2)/ImgH<2.3； (19)

when the above equation (19) is satisfied, it is advantageous to secure the angle of view of the optical system and effectively control the amount of distortion of the optical system.

An example 1 of the wide-angle endoscope optical system is as follows: the S line and the T line marked in the astigmatism diagram of the optical system respectively represent a sagittal plane and a tangential plane.

The following table is a table of lens data for examples of the invention

TABLE 1 lens data table of example 1 of the wide-angle endoscope optical system

TABLE 1

Table 2 shows the ratio of the aspherical rise to the radius R of each of the first lens L1 and the second lens L2 in example 1 of the wide-angle endoscope optical system

TABLE 2

Table 3 shows the ratio of the aspherical height to the radius R of each of the third lens L3 and the fourth lens L4 in example 1 of the wide-angle endoscope optical system

TABLE 3

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