CN107748435A - Optical system of fisheye endoscope with super wide angle - Google Patents

Abstract

The present application relates to endoscopes, and more particularly, to fisheye endoscope optical systems having ultra-wide angles. Include from the object plane to the image plane along the optical axis in proper order: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens; through carrying out reasonable collocation with first lens to ninth lens, utilize the characteristics of each lens self structure for the angle of view of camera lens reaches 230, and formation of image on the CCD of image plane or CMOS can observe the picture of wider scope, and the camera lens that need not frequently move comes the conversion visual angle to observe the shooting in narrow and small viscus space, has improved work efficiency.

Description

Optical system of fisheye endoscope with super wide angle

【Technical field】

The present application relates to endoscopes, in particular to a fisheye endoscope optical system with an ultra-wide angle.

【Background technique】

Endoscope is a kind of medical device commonly used in the medical field at present, which is composed of a bendable part, a light source and a lens. When in use, the endoscope is introduced into the lesion to be inspected, and the rear end is connected to a photoelectric sensor CCD or CMOS, and the image information of the lesion is imaged by the lens and imaged on the photoelectric sensor for the doctor to intuitively distinguish the change of the lesion And perform precise surgery directly in the visible state. Therefore, the image quality of the lens affects the use effect of the endoscope. For the lens, it is mainly the field of view, resolution and illumination factors. With the development of fisheye lens and the emergence of high-pixel chips, it is beneficial to apply the super wide-angle fisheye lens to the endoscope. Improved work efficiency.

【Content of invention】

In order to solve the problem that the angle of the endoscope can be made small in the prior art, the present application provides a fisheye endoscope optical system with an ultra-wide angle.

The application is achieved through the following technical solutions:

The optical system of the fisheye endoscope with ultra-wide angle includes: the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens a lens, an eighth lens, and a ninth lens;

The object side of the first lens is convex, and the image side is convex;

The object plane side of the second lens is a plane, and the image plane side is a convex surface;

The object side of the third lens is concave, and the image side is convex;

The object plane side of the fourth lens is a convex surface, and the image plane side is a concave surface;

The object side of the fifth lens is convex, and the image side is concave;

The object side of the sixth lens is a convex surface, and the image side is a concave surface;

The object side of the seventh lens is concave, and the image side is convex;

The object side of the eighth lens is convex, and the image side is concave;

The object side of the ninth lens is convex, and the image side is flat.

As mentioned above, the fisheye endoscope optical system with super wide angle also meets the following conditions:

(1) 1.70<Nd1<1.90; 20<Vd1<40;

(2) 1.70<Nd2<1.90; 35<Vd2<50;

(3) 1.70<Nd3<1.90; 35<Vd3≤50;

(4) 1.80<Nd4<1.95; 20<Vd4<35;

(5) 1.50<Nd5<1.75; 20<Vd5<40;

(6) 1.65<Nd6<1.75; 30<Vd6<65;

(7) 1.80<Nd7<1.95; 20<Vd7<35;

(8) 1.70<Nd8<1.85; 35<Vd8<55;

(9) 1.70<Nd9<1.85; 30<Vd9<55;

Wherein, Nd1 is the refractive index of the first lens, Vd1 is the dispersion coefficient of the first lens; Nd2 is the refractive index of the second lens, Vd2 is the dispersion coefficient of the second lens; Nd3 is the refractive index of the third lens, and Vd3 is the first lens The dispersion coefficient of the three lenses; Nd4 is the refractive index of the fourth lens, Vd4 is the dispersion coefficient of the fourth lens; Nd5 is the refractive index of the fifth lens, Vd5 is the dispersion coefficient of the fifth lens; Nd6 is the refractive index of the sixth lens , Vd6 is the dispersion coefficient of the sixth lens; Nd7 is the refractive index of the seventh lens, Vd7 is the dispersion coefficient of the seventh lens; Nd8 is the refractive index of the eighth lens, Vd8 is the dispersion coefficient of the eighth lens; Nd9 is the ninth The refractive index of the lens, Vd9 is the dispersion coefficient of the ninth lens.

In the above-mentioned fisheye endoscope optical system with super wide angle, the refractive power of the first lens is negative, and its focal length f1 is -5.8mm.

According to the above-mentioned fisheye endoscope optical system with super wide angle, the refractive power of the second lens is negative, and its focal length f2 is -3.6mm.

In the above-mentioned fisheye endoscope optical system with super wide angle, the refractive power of the third lens is negative, and its focal length f3 is -3.3mm.

According to the above-mentioned fisheye endoscope optical system with super wide angle, the refractive power of the fourth lens is positive, and its focal length f4 is 6 mm.

According to the above-mentioned fisheye endoscope optical system with super wide angle, the refractive power of the fifth lens is positive, and its focal length f5 is 5.6mm.

According to the above-mentioned fisheye endoscope optical system with super wide angle, the refractive power of the sixth lens is positive, and its focal length f6 is 4.2mm.

In the above-mentioned fisheye endoscope optical system with super wide angle, the refractive power of the seventh lens is negative, and its focal length f7 is -2.6mm.

According to the above-mentioned fisheye endoscope optical system with super wide angle, the refractive power of the eighth lens is positive, and its focal length f7 is 3.7mm.

Compared with the prior art, the present application has the following advantages:

1. This application provides an ultra-wide-angle fisheye endoscope optical system. By reasonably matching the first lens to the ninth lens and utilizing the characteristics of each lens' own structure, the field of view of the lens reaches 230°. Imaging on the CCD or CMOS of the image plane can observe a larger range of pictures, and observe and shoot in a small visceral space without frequently moving the lens to change the viewing angle, which improves work efficiency.

【Description of drawings】

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

FIG. 1 is a schematic structural view of the optical system of the fisheye endoscope with an ultra-wide angle in the present application.

Fig. 2 is the imaging schematic diagram of the present application;

Figure 3 is a partially enlarged view of Figure 2;

Fig. 4 is the MTF transfer function curve figure of the present application;

Fig. 5 is the color difference control chart of the present application;

FIG. 6 is a diagram of the spot diameter of the present application.

【Detailed ways】

In order to make the technical problems, technical solutions and beneficial effects solved by the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not intended to limit the present application.

The application is achieved through the following technical solutions:

As shown in Figures 1 to 6, the optical system of a fisheye endoscope with an ultra-wide angle includes in sequence from the object plane to the image plane along the optical axis: a first lens 1, a second lens 2, a third lens 3, a fourth lens Lens 4, fifth lens 5, sixth lens 6, seventh lens 7, eighth lens 8, and ninth lens 9; characterized in that,

The object side of the first lens 1 is convex, and the image side is convex;

The object plane side of the second lens 2 is a plane, and the image plane side is a convex surface;

The object side of the third lens 3 is concave, and the image side is convex;

The object plane side of the fourth lens 4 is a convex surface, and the image plane side is a concave surface;

The object plane side of the fifth lens 5 is a convex surface, and the image plane side is a concave surface;

The object plane side of the sixth lens 6 is a convex surface, and the image plane side is a concave surface;

The object plane side of the seventh lens 7 is a concave surface, and the image plane side is a convex surface;

The object plane side of the eighth lens 8 is a convex surface, and the image plane side is a concave surface;

The object plane side of the ninth lens 9 is convex, and the image plane side is plane.

By rationally matching the first lens 1 to the ninth lens 9 and using the characteristics of each lens' own structure, the field of view of the lens can reach 230°, and the imaging on the CCD or CMOS of the image plane can observe a larger The range of pictures, in the small visceral space, does not need to frequently move the lens to change the angle of view for observation and shooting, which improves work efficiency.

Further, the described fisheye endoscope optical system with super wide angle also satisfies the following conditions:

(1) 1.70<Nd1<1.90; 20<Vd1<40;

(2) 1.70<Nd2<1.90; 35<Vd2<50;

(3) 1.70<Nd3<1.90; 35<Vd3≤50;

(4) 1.80<Nd4<1.95; 20<Vd4<35;

(5) 1.50<Nd5<1.75; 20<Vd5<40;

(6) 1.65<Nd6<1.75; 30<Vd6<65;

(7) 1.80<Nd7<1.95; 20<Vd7<35;

(8) 1.70<Nd8<1.85; 35<Vd8<55;

(9) 1.70<Nd9<1.85; 30<Vd9<55;

Wherein, Nd1 is the refractive index of the first lens 1, Vd1 is the dispersion coefficient of the first lens 1; Nd2 is the refractive index of the second lens 2, Vd2 is the dispersion coefficient of the second lens 2; Nd3 is the refraction coefficient of the third lens 3 Vd3 is the dispersion coefficient of the third lens 3; Nd4 is the refractive index of the fourth lens 4, and Vd4 is the dispersion coefficient of the fourth lens 4; Nd5 is the refractive index of the fifth lens 5, and Vd5 is the dispersion of the fifth lens 5 Coefficient; Nd6 is the refractive index of the sixth lens 6, and Vd6 is the dispersion coefficient of the sixth lens 6; Nd7 is the refractive index of the seventh lens 7, and Vd7 is the dispersion coefficient of the seventh lens 7; Nd8 is the refraction coefficient of the eighth lens 8 Vd8 is the dispersion coefficient of the eighth lens 8; Nd9 is the refractive index of the ninth lens 9, and Vd9 is the dispersion coefficient of the ninth lens 9. The lens dispersion coefficient of different refractive index materials is also different. The higher the refractive index, the lower the dispersion coefficient. After reasonable matching of the different properties of each lens, the dispersion range of the light to the image plane is small, making the imaging of the endoscope lens more clearly.

Still further, the refractive power of the first lens 1 is negative, its focal length is -6mm<f1<-4mm, and its preferred focal length f1 is -5.8mm. The refractive index Nd1 of the first lens 1 is preferably 1.77, and the dispersion coefficient Vd1 is preferably 28, which is beneficial for the optical system or lens to form a clear image.

Still further, the refractive power of the second lens 2 is negative, and its focal length is -4mm<f2<-3mm, and its preferred focal length f2 is -3.6mm. The refractive index Nd2 of the second lens 2 is preferably 1.78, and the dispersion coefficient Vd2 is preferably 50, which is beneficial for the optical system or lens to form a clear image.

Still further, the refractive power of the third lens 3 is negative, and its focal length is -4mm<f3<-3mm, and its preferred focal length f3 is -3.3mm. The refractive index Nd3 of the third lens 3 is preferably 1.78, and the dispersion coefficient Vd3 is preferably 50, which is beneficial for the optical system or lens to form a clear image.

Specifically, the fourth lens 4 has a positive refractive power, and its focal length is 5mm<f4<7mm, and its preferred focal length f4 is 6mm. The refractive index Nd4 of the fourth lens 4 is preferably 1.90, and the dispersion coefficient Vd4 is preferably 23, which is beneficial for the optical system or lens to form a clear image.

Specifically, the fifth lens 5 has positive refractive power, and its focal length is 5mm<f5<7mm, and its preferred focal length f5 is 5.6mm. The refractive index Nd5 of the fifth lens 5 is preferably 1.70, and the dispersion coefficient Vd5 is preferably 35, which is beneficial for the optical system or lens to form a clear image.

Specifically, the sixth lens 6 has positive refractive power, and its focal length is 4mm<f6<6mm, and its preferred focal length f6 is 4.2mm. The refractive index Nd6 of the sixth lens 6 is preferably 1.72, and the dispersion coefficient Vd6 is preferably 55, which is beneficial for the optical system or lens to form a clear image.

Specifically, the seventh lens 7 has negative refractive power, its focal length is -3mm<f7<-2mm, and its preferred focal length f7 is -2.6mm. The refractive index Nd7 of the seventh lens 7 is preferably 1.90, and the dispersion coefficient Vd7 is preferably 23, which is beneficial for the optical system or lens to form a clear image.

More specifically, the image plane side of the sixth lens 6 and the object plane side of the seventh lens 7 are cemented to form a combined lens, and its focal length f67 is -6.3mm. It is beneficial to make the optical system or lens form a clear image.

Specifically, the eighth lens 8 has a positive refractive power, and its focal length is 3mm<f8<5mm, and its preferred focal length f8 is 3.7mm. The refractive index Nd8 of the eighth lens 8 is preferably 1.80, and the dispersion coefficient Vd8 is preferably 45, which is beneficial for the optical system or lens to form a clear image.

Specifically, the ninth lens 9 has positive refractive power, and its focal length is 4mm<f9<6mm, and its preferred focal length f9 is 4.7mm. The refractive index Nd9 of the ninth lens 9 is preferably 1.72, and the dispersion coefficient Vd9 is preferably 48, which is beneficial for the optical system or lens to form a clear image.

More specifically, an optical filter 11 and a protective glass 12 are provided behind the ninth lens 9, which is beneficial for the optical system or the lens to form a clear image.

Specifically, in this embodiment, the basic parameters of the optical lens are shown in the following table:

In the above table, from the object plane to the image plane 10 along the optical axis, S1 and S2 correspond to the two surfaces of the first lens 1; S3 and S4 correspond to the two surfaces of the second lens 2; S5 and S6 correspond to the third The two surfaces of the lens 3; S7 and S8 correspond to the two surfaces of the fourth lens 4; S9 and S10 correspond to the two surfaces of the fifth lens 5; STO is the position of the diaphragm; S11 and S12 correspond to the sixth lens 6; S13, S14 correspond to the two surfaces of the seventh lens 7; S15, S16 correspond to the two surfaces of the eighth lens 8; S17, S18 correspond to the two surfaces of the ninth lens 9.

It can be seen from Fig. 2, Fig. 3, Fig. 4, Fig. 5, and Fig. 6 that this optical system has good optical performance. The bands converge on a single pixel at the end and no rays converge on the rest of the pixels.

This application provides an ultra-wide-angle fisheye endoscope optical system. By reasonably matching the first lens 1 to the ninth lens 9, and utilizing the characteristics of each lens' own structure, the field of view of the lens reaches 230°. Imaging on the CCD or CMOS of the image plane can observe a larger range of pictures, and observe and shoot in a small visceral space without frequently moving the lens to change the viewing angle, which improves work efficiency. Moreover, the overall size is small and easy to use. It adopts a structure composed of nine glass lenses and has a high resolution. It can achieve an imaging effect of 5 million pixels, making the captured picture clearer and helping doctors to make more accurate judgments.

The foregoing is one or more implementation modes provided in conjunction with specific content, and it is not considered that the specific implementation of the application is limited to these descriptions. Anything that is similar or identical to the methods and structures of this application, or some technical deduction or replacement based on the concept of this application should be regarded as the scope of protection of this application.

Claims (10)

1. the flake endoscope optical system with ultra-wide angle, includes successively along optical axis from object plane to image planes：First lens (1), Second lens (2), the 3rd lens (3), the 4th lens (4), the 5th lens (5), the 6th lens (6), the 7th lens (7), the 8th Lens (8) and the 9th lens (9)；Characterized in that,

First lens (1) the object plane side is convex surface, and image planes side is convex surface；

Second lens (2) the object plane side is plane, and image planes side is convex surface；

3rd lens (3) the object plane side is concave surface, and image planes side is convex surface；

4th lens (4) the object plane side is convex surface, and image planes side is concave surface；

5th lens (5) the object plane side is convex surface, and image planes side is concave surface；

6th lens (6) the object plane side is convex surface, and image planes side is concave surface；

7th lens (7) the object plane side is concave surface, and image planes side is convex surface；

8th lens (8) the object plane side is convex surface, and image planes side is concave surface；

9th lens (9) the object plane side is convex surface, and image planes side is plane.

2. the flake endoscope optical system according to claim 1 with ultra-wide angle, it is characterised in that also meet as follows Condition：

(1)1.70<Nd1<1.90；20<Vd1<40；

(2)1.70<Nd2<1.90；35<Vd2<50；

(3)1.70<Nd3<1.90；35<Vd3≤50；

(4)1.80<Nd4<1.95；20<Vd4<35；

(5)1.50<Nd5<1.75；20<Vd5<40；

(6)1.65<Nd6<1.75；30<Vd6<65；

(7)1.80<Nd7<1.95；20<Vd7<35；

(8)1.70<Nd8<1.85；35<Vd8<55；

(9)1.70<Nd9<1.85；30<Vd9<55；

Wherein, Nd1 is the refractive index of the first lens (1), and Vd1 is the abbe number of the first lens (1)；Nd2 is the second lens (2) Refractive index, Vd2 be the second lens (2) abbe number；Nd3 is the refractive index of the 3rd lens (3), and Vd3 is the 3rd lens (3) Abbe number；Nd4 is the refractive index of the 4th lens (4), and Vd4 is the abbe number of the 4th lens (4)；Nd5 is the 5th lens (5) refractive index, Vd5 are the abbe number of the 5th lens (5)；Nd6 is the refractive index of the 6th lens (6), and Vd6 is the 6th lens (6) abbe number；Nd7 is the refractive index of the 7th lens (7), and Vd7 is the abbe number of the 7th lens (7)；Nd8 is the 8th saturating The refractive index of mirror (8), Vd8 are the abbe number of the 8th lens (8)；Nd9 is the refractive index of the 9th lens (9), and Vd9 is the 9th saturating The abbe number of mirror (9).

3. the flake endoscope optical system according to claim 1 or 2 with ultra-wide angle, it is characterised in that described The focal power of one lens (1) is negative, and its focal length f1 is -5.8mm.

4. the flake endoscope optical system according to claim 1 or 2 with ultra-wide angle, it is characterised in that described The focal power of two lens (2) is negative, and its focal length f2 is -3.6mm.

5. the flake endoscope optical system according to claim 1 or 2 with ultra-wide angle, it is characterised in that described The focal power of three lens (3) is negative, and its focal length f3 is -3.3mm.

6. the flake endoscope optical system according to claim 1 or 2 with ultra-wide angle, it is characterised in that described The focal power of four lens (4) is just, its focal length f4 is 6mm.

7. the flake endoscope optical system according to claim 1 or 2 with ultra-wide angle, it is characterised in that described The focal power of five lens (5) is just, its focal length f5 is 5.6mm.

8. the flake endoscope optical system according to claim 1 or 2 with ultra-wide angle, it is characterised in that described The focal power of six lens (6) is just, its focal length f6 is 4.2mm.

9. the flake endoscope optical system according to claim 1 or 2 with ultra-wide angle, it is characterised in that described The focal power of seven lens (7) is negative, and its focal length f7 is -2.6mm.

10. the flake endoscope optical system according to claim 1 or 2 with ultra-wide angle, it is characterised in that described The focal power of eight lens (8) is just, its focal length f7 is 3.7mm.