Medical endoscope optical system and camera module applied by same

Abstract

The utility model provides a medical endoscope optical system and an applied camera module thereof, the medical endoscope optical system is composed of five lenses, the first lens has negative focal power, the image side surface of the first lens is a concave surface, the second lens has positive focal power, the object side surface of the second lens is a convex surface, the image side surface of the second lens is a convex surface, the third lens has positive focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface. The fourth lens has positive focal power, the object side surface of the fourth lens is a convex surface, the image side surface of the fifth lens is a concave surface, the fifth lens has negative focal power, and the object side surface of the fifth lens is a concave surface, so that the optical lens can have the characteristic of small aperture while having a large field angle range by selecting a proper number of lenses and reasonably configuring the refractive power and the surface shape of each lens; and meanwhile, the medical endoscopic optical lens has good imaging resolution so as to meet the high-definition imaging requirement of the medical endoscopic optical lens.

Description

Technical Field

[0001] This application relates to the field of optical imaging, and particularly to a medical endoscope optical system and a camera module applied thereto. Background Art

[0002] As an important device for minimally invasive surgery, the endoscope enters the human body cavity through the body's natural orifice or surgical incision, and can perform real-time dynamic imaging on local micro tissues to achieve precise positioning of the lesion location. With the trend of increasingly miniaturized medical incisions, it is required that the diameter of the endoscope be as small as possible to reduce the discomfort to the human body, while maintaining high-definition imaging. Therefore, a medical endoscope optical system with a small diameter and a large depth of field is needed. Utility Model Content

[0003] This application aims to provide a medical endoscope optical system that has the characteristics of a small diameter and a large depth of field, and can ensure good imaging quality at the same time.

[0004] A medical endoscope optical system sequentially includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens along the optical axis from the object plane to the image plane;

[0005] The first lens has a negative optical power, and its image side is concave;

[0006] The second lens has a positive optical power, its object side is convex, and its image side is convex;

[0007] The third lens has a positive optical power, its object side is convex, and its image side is convex;

[0008] The fourth lens has a positive optical power, its object side is convex, and its image side is convex;

[0009] The fifth lens has a negative optical power, and its object side is concave.

[0010] For the medical endoscope optical system as described above, the optical system satisfies the following relationship: 23.3 < HFOV / (Fno * DT11) < 27.0;

[0011] Wherein, HFOV is half of the maximum field of view angle of the optical system, Fno is the F-number of the optical system, and DT11 is the maximum effective radius of the object side of the first lens of the optical system.

[0012] For the medical endoscope optical system as described above, the optical system satisfies the following relationship: 3.4 < TTL / (2 * ImgH) < 5.3;

[0013] Among them, TTL is the maximum axial distance from the inner surface of the effective light-passing aperture on the object side of the first lens to the imaging surface, and ImagH is half of the diagonal length of the effective pixel area on the imaging surface.

[0014] For the medical endoscope optical system as described above, the optical system satisfies the following relationship: 1.1 < f23 / f < 2.1;

[0015] Among them, f23 is the combined focal length of the second lens and the third lens, and f is the effective focal length of the optical system.

[0016] For the medical endoscope optical system as described above, the optical system satisfies the following relationship: 3.1 ≤ |(f2 - f1) / f1| ≤ 4.6;

[0017] Among them, f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.

[0018] For the medical endoscope optical system as described above, the optical system satisfies the following relationship: 2.6 < (f3 + f4) / (f3 - f4) < 4.3;

[0019] Among them, f3 is the effective focal length of the third lens, and f4 is the effective focal length of the fourth lens.

[0020] For the medical endoscope optical system as described above, the optical system satisfies the following relationship: 0.2 < |R4 / R5| < 2.3; 1.6 < |(R6 + R7) / R7| < 3.2;

[0021] Among them, R4 is the radius of curvature of the image side of the second lens, R5 is the radius of curvature of the object side of the third lens, R6 is the radius of curvature of the image side of the third lens, and R7 is the radius of curvature of the object side of the fourth lens.

[0022] For the medical endoscope optical system as described above, the optical system satisfies the following relationship: 4.3 ≤ CT2 / DT22 ≤ 8.6;

[0023] Among them, CT2 is the central thickness of the second lens on the optical axis, and DT22 is the maximum effective radius of the image side of the second lens.

[0024] For the medical endoscope optical system as described above, the optical system satisfies the following relationship:

[0025] 8.1 < DT41 / SAG7 < 13.8;

[0026] Among them, DT41 is the maximum effective radius of the object side of the fourth lens, and SAG7 is the distance parallel to the optical axis from the maximum effective light-passing aperture on the object side of the fourth lens to the intersection of the object side of the fourth lens and the optical axis.

[0027] The medical endoscope optical system described above satisfies the following relationships: the F-number of the optical system < 4.7, the full field of view angle FOV ≥ 90°, and the total lens length TTL < 3.8 mm.

[0028] On the other hand, an embodiment of the present application further provides an imaging module, which at least includes an optical lens, and the above-mentioned medical endoscope optical system is installed in the optical lens.

[0029] Compared with the prior art, the beneficial effects of the present application are as follows:

[0030] The present utility model provides a medical endoscope optical system and an imaging module to which it is applied, which is composed of five lenses. The first lens has a negative optical power, and its image side is concave. The second lens has a positive optical power, its object side is convex, and its image side is convex. The third lens has a positive optical power, its object side is convex, and its image side is convex. The fourth lens has a positive optical power, its object side is convex, and its image side is convex. The fifth lens has a negative optical power, and its object side is concave. By selecting an appropriate number of lenses and reasonably configuring the refractive power and surface shape of each lens, the optical lens can have a large field of view angle range while having a small aperture, and at the same time has good imaging resolution to meet the high-definition imaging requirements of medical endoscope optical lenses. Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments.

[0032] Figure 1 It is a schematic structural diagram of the optical system or imaging module in Embodiment 1 of the present application;

[0033] Figure 2 It is the axial chromatic aberration, astigmatism and distortion curves of the optical system or imaging module in Embodiment 1 of the present application;

[0034] Figure 3 It is a schematic structural diagram of the optical system or imaging module in Embodiment 2 of the present application;

[0035] Figure 4 It is the axial chromatic aberration, astigmatism and distortion curves of the optical system or imaging module in Embodiment 2 of the present application;

[0036] Figure 5 It is a schematic structural diagram of the optical system or imaging module in Embodiment 3 of the present application;

[0037] Figure 6 It is the axial chromatic aberration, astigmatism and distortion curves of the optical system or imaging module in Embodiment 3 of the present application;

[0038] Figure 7It is a schematic structural diagram of the optical system or camera module in Embodiment 4 of the present application;

[0039] Figure 8 It is the axial chromatic aberration, astigmatism and distortion curves of the optical system or camera module in Embodiment 4 of the present application. Detailed implementation manners

[0040] As Figure 1-8 shown, a medical endoscope optical system of the present application includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, an infrared filter and an image-side protective glass sequentially arranged from the object side. The aperture stop is disposed between the second lens and the third lens. The first lens, the second lens, the third lens, the fourth lens and the fifth lens are spherical lenses, and are all separated with air intervals. The first lens has a negative focal power, and its image side is concave; the second lens has a positive focal power, its object side is convex, and its image side is convex; the third lens has a positive focal power, its object side is convex, and its image side is convex; the fourth lens has a positive focal power, its object side is convex, and its image side is convex; the fifth lens has a negative focal power, and its object side is concave; the F number of the medical endoscope optical system < 4.7; the full field of view angle FOV of the medical endoscope optical system ≥ 90°; the total lens length TTL < 3.8 mm.

[0041] The optical system of the embodiment of the present application is composed of 5 lenses. By selecting an appropriate number of lenses and reasonably configuring the refractive powers and surface shapes of each lens, the optical lens can have the characteristics of a large field of view angle range and a small aperture, and at the same time has good imaging resolution to meet the high-definition imaging requirements of the medical endoscope optical lens.

[0042] Furthermore, the optical system satisfies the following relationship: 23.3 < HFOV / (Fno * DT11) < 27.0, where HFOV is half of the maximum field of view angle of the optical imaging system, Fno is the F number of the optical imaging system, and DT11 is the maximum effective radius of the object side of the first lens of the optical imaging system. This relational expression reflects the constraint situation of the optical lens in terms of the field of view angle and miniaturization characteristics, so that the optical system has the characteristics of a large field of view angle and miniaturization while meeting the large field of view angle requirement. When it is lower than the lower limit of the relational expression, on the basis of ensuring that the field of view angle of the optical lens is a large field of view angle, Fno * DT11 further increases, which will increase the aperture of the optical lens and is not conducive to the miniaturization of the optical lens; when it exceeds the upper limit of the relational expression, it is difficult for the optical lens to obtain good imaging resolution.

[0043] Furthermore, the optical system satisfies the following relationship: 3.4 < TTL / (2*ImgH) < 5.3, where TTL is the maximum axial distance from the inner surface of the effective light-passing aperture of the object side of the first lens to the imaging surface, and ImagH is half of the diagonal length of the effective pixel region on the imaging surface. This relational expression reflects the constraint situation of the thinness and lightness of the optical lens, enabling the optical system to limit the overall length while satisfying the size of the imaging frame, so as to ensure the miniaturization of the optical system. When below the lower limit of the relational expression, on the basis of ensuring the size of the effective imaging region on the imaging surface of the optical lens, if TTL is further reduced, the thinness and lightness of the optical lens will be overly compressed, which is not conducive to the improvement of the performance of the optical lens; if it exceeds the upper limit of the relational expression, it is not conducive to the reduction of the volume of the optical lens.

[0044] Furthermore, the optical system satisfies the following relationship: 1.1 < f23 / f < 2.1, where f23 is the combined focal length of the second lens and the third lens, and f is the effective focal length of the optical imaging system. The second lens provides positive refractive power for the optical system, and the third lens provides positive refractive power for the optical system. Controlling the relationship between the combined focal length of the two lenses and the effective focal length of the system within a reasonable range is conducive to the mutual correction of aberrations. If it exceeds the upper limit of the relational expression, the refractive power of the lens combination is too small, which is likely to generate large marginal aberrations and chromatic aberrations, and is not conducive to improving the resolution performance; if it exceeds the lower limit of the relational expression, the refractive power of the lens combination is too strong, making the lens group prone to serious astigmatism phenomena, and is not conducive to the improvement of the imaging quality.

[0045] Furthermore, the optical system satisfies the following relationship: 3.1 ≤ |(f2 - f1) / f1| ≤ 4.6, where f1 is the effective focal length of the first lens and f2 is the effective focal length of the second lens. By limiting the effective focal lengths of the first lens and the second lens of the optical imaging system within a reasonable range, the contributions of spherical aberration and coma of the first lens and the second lens can be effectively constrained, and after balancing, their sensitivity can be kept at a reasonable level.

[0046] Further, the optical system satisfies the following relationship: 2.6 < (f3 + f4) / (f3 - f4) < 4.3, where f3 is the effective focal length of the third lens and f4 is the effective focal length of the fourth lens. By adjusting the optical powers of the third lens and the fourth lens, it is possible to avoid excessive concentration of the optical power on the fourth lens, and at the same time, it helps to constrain the surface shape of the image side of the fourth lens, avoiding excessive bending and affecting the processability of the fourth lens. In addition, by satisfying the above relationship, it is also possible to further enhance the correction of higher-order aberrations on the basis of reducing third-order aberrations such as spherical aberration, coma, and field curvature, and reduce the tolerance sensitivity of the optical lens. When exceeding the lower limit of the above relationship, the optical power of the fourth lens is too concentrated, resulting in excessive bending of the object side surface shape of the fourth lens, which is not conducive to the processability of the fourth lens. When exceeding the upper limit of the above relationship, the optical power of the fourth lens is insufficient, which is not conducive to the correction of the aberrations of the optical lens and affects the tolerance sensitivity of the optical lens.

[0047] Further, the optical system satisfies the following relationship: 0.2 < |R4 / R5| < 2.3, where R4 is the radius of curvature of the image side of the second lens and R5 is the radius of curvature of the object side of the third lens. When the above conditional expression is satisfied, by reasonably controlling the ratio range of the radius of curvature of the image side of the second lens to the radius of curvature of the object side of the third lens, it is beneficial to control the bending degrees of the second lens and the third lens, beneficial to correcting the marginal aberrations of the imaging optical system, reducing the generation of astigmatism, and improving the imaging effect of the imaging optical system. When exceeding the upper limit of the above relationship, it is not conducive to the correction of the aberrations of the imaging optical system; when lower than the lower limit of the above relationship, the risk of ghost images appears, limiting the imaging performance of the imaging optical system.

[0048] Further, the optical system satisfies the following relationship: 1.6 < |(R6 + R7) / R7| < 3.2, where R6 is the radius of curvature of the image side of the third lens and R7 is the radius of curvature of the object side of the fourth lens. By controlling the radius of curvature of the image side of the third lens and the radius of curvature of the object side of the fourth lens within a reasonable range, it is possible to make the optical system have the characteristics of small light deflection angle and easy processing.

[0049] Further, the optical system satisfies the following relationship: 4.3 ≤ CT2 / DT22 ≤ 8.6, where CT2 is the central thickness of the second lens on the optical axis and DT22 is the maximum effective radius of the image side of the second lens. When the above conditional expression is satisfied, since the maximum effective semi-aperture of the lens and the thickness of the lens itself affect each other, by reasonably controlling the size of the maximum effective semi-aperture of the image side of the second lens, it is possible to reasonably shorten the central thickness of the second lens on the optical axis, which is beneficial to reducing the overall optical length of the optical system.

[0050] Furthermore, the optical system satisfies the following relationship: 8.1 < DT41 / SAG7 < 13.8, where DT41 is the maximum effective radius of the object side surface of the fourth lens, and SAG7 is the distance parallel to the optical axis from the maximum effective clear aperture of the object side surface of the fourth lens to the intersection of the object side surface of the fourth lens and the optical axis. By making the optical system satisfy the above relationship, it is beneficial to prevent the surface shape of the object side surface of the fourth lens from being overly curved, thereby reducing the processing difficulty of the fourth lens.

[0051] Embodiment 1

[0052] The following refers to Figures 1 to 2 Describe the optical imaging lens according to Embodiment 1 of the present application. Figure 1 Fig. shows a schematic structural diagram of the optical imaging lens according to Embodiment 1 of the present application.

[0053] As Figure 1 shown, the optical imaging lens according to an exemplary embodiment of the present application sequentially includes, along the optical axis from the object side to the image side: a first lens E1, a second lens E2, a STO, a third lens E3, a fourth lens E4, a fifth lens E5, an infrared filter IR, an image-side protective glass CG, and an imaging surface S15.

[0054] The first lens E1 has a negative optical power, its object side surface S1 is a plane, and its image side surface S2 is a concave surface. The second lens E2 has a positive optical power, its object side surface S3 is a convex surface, and its image side surface S4 is a convex surface. The third lens E3 has a positive optical power, its object side surface S5 is a convex surface, and its image side surface S6 is a convex surface. The fourth lens E4 has a positive optical power, its object side surface S7 is a convex surface, and its image side surface S8 is a convex surface. The fifth lens E5 has a negative optical power, its object side surface S9 is a concave surface, and its image side surface S10 is a plane. The filter IR has an object side surface S11 and an image side surface S12. The image-side protective glass CG has an object side surface S13 and an image side surface S14. Light from the object sequentially passes through the surfaces S1 to S14 and finally forms an image on the imaging surface S15.

[0055] Table 1 shows the surface types, curvature radii, thicknesses, and materials of the lenses of the optical imaging lens of Embodiment 1, where the units of the curvature radii and thicknesses are both millimeters (mm).

[0056] Table 1

[0057]

[0058] Figure 2 Fig. shows the axial chromatic aberration, astigmatism, and distortion curves of the optical imaging lens of Embodiment 1. The axial chromatic aberration represents the deviation of the convergence points of light rays of different wavelengths after passing through the lens; the astigmatism represents the curvature of the meridional image plane and the curvature of the sagittal image plane; the distortion represents the distortion magnitude values corresponding to different image heights. The optical imaging lens given in Embodiment 1 can achieve good imaging quality.

[0059] Example 2

[0060] The following refers to Figures 3 to 4 Describe the optical imaging lens according to Embodiment 2 of the present application. Figure 3 Fig. shows a schematic structural diagram of the optical imaging lens according to Embodiment 2 of the present application.

[0061] As Figure 3 shown, the optical imaging lens according to the exemplary embodiment of the present application sequentially includes, along the optical axis from the object side to the image side: a first lens E1, a second lens E2, a STO, a third lens E3, a fourth lens E4, a fifth lens E5, an infrared filter IR, an image-side protective glass CG, and an imaging surface S15.

[0062] The first lens E1 has a negative optical power, its object surface S1 is concave, and its image surface S2 is concave. The second lens E2 has a positive optical power, its object surface S3 is convex, and its image surface S4 is convex. The third lens E3 has a positive optical power, its object surface S5 is convex, and its image surface S6 is convex. The fourth lens E4 has a positive optical power, its object surface S7 is convex, and its image surface S8 is convex. The fifth lens E5 has a negative optical power, its object surface S9 is concave, and its image surface S10 is convex. The filter IR has an object surface S11 and an image surface S12. The image-side protective glass CG has an object surface S13 and an image surface S14. Light from the object sequentially passes through the surfaces S1 to S14 and finally forms an image on the imaging surface S15.

[0063] Table 2 shows the surface types, curvature radii, thicknesses, and materials of the lenses of the optical imaging lens of Embodiment 2, where the units of the curvature radii and thicknesses are both millimeters (mm).

[0064] Table 2

[0065]

[0066] Figure 4 Fig. shows the axial chromatic aberration, astigmatism, and distortion curves of the optical imaging lens of Embodiment 2. The axial chromatic aberration represents the deviation of the convergence points of light rays of different wavelengths after passing through the lens; the astigmatism represents the curvature of the meridional image plane and the curvature of the sagittal image plane; the distortion represents the distortion magnitude values corresponding to different image heights. The optical imaging lens given in Embodiment 2 can achieve good imaging quality.

[0067] Example 3

[0068] The following refers to Figures 5 to 6 Describe the optical imaging lens according to Embodiment 3 of the present application. Figure 5 Fig. shows a schematic structural diagram of the optical imaging lens according to Embodiment 3 of the present application.

[0069] AsFigure 5 As shown, the optical imaging lens according to an exemplary embodiment of the present application sequentially includes, from the object side to the image side along the optical axis: a first lens E1, a second lens E2, an STO, a third lens E3, a fourth lens E4, a fifth lens E5, an infrared filter IR, an image-side protective glass CG, and an imaging surface S15.

[0070] The first lens E1 has a negative optical power, its object surface S1 is concave, and its image surface S2 is concave. The second lens E2 has a positive optical power, its object surface S3 is convex, and its image surface S4 is convex. The third lens E3 has a positive optical power, its object surface S5 is convex, and its image surface S6 is convex. The fourth lens E4 has a positive optical power, its object surface S7 is convex, and its image surface S8 is convex. The fifth lens E5 has a negative optical power, its object surface S9 is concave, and its image surface S10 is concave. The filter IR has an object surface S11 and an image surface S12. The image-side protective glass CG has an object surface S13 and an image surface S14. Light from the object sequentially passes through the surfaces S1 to S14 and finally forms an image on the imaging surface S15.

[0071] Table 3 shows the surface types, curvature radii, thicknesses, and materials of the lenses of the optical imaging lens of Example 3, where the units of the curvature radii and thicknesses are both millimeters (mm).

[0072] Table 3

[0073]

[0074] Figure 6 shows the axial chromatic aberration, astigmatism, and distortion curves of the optical imaging lens of Example 3. The axial chromatic aberration represents the deviation of the convergence points of light rays of different wavelengths after passing through the lens; the astigmatism represents the curvature of the meridional image plane and the curvature of the sagittal image plane; the distortion represents the distortion magnitude values corresponding to different image heights. The optical imaging lens given in Example 3 can achieve good imaging quality.

[0075] Example Four

[0076] The following refers to Figures 7 to 8 to describe the optical imaging lens according to Embodiment 4 of the present application. Figure 7 shows a schematic structural diagram of the optical imaging lens according to Embodiment 4 of the present application.

[0077] As Figure 7 shown, the optical imaging lens according to an exemplary embodiment of the present application sequentially includes, from the object side to the image side along the optical axis: a first lens E1, a second lens E2, an STO, a third lens E3, a fourth lens E4, a fifth lens E5, an infrared filter IR, an image-side protective glass CG, and an imaging surface S15.

[0078] The first lens E1 has a negative optical power. Its object side S1 is a plane, and its image side S2 is a concave surface. The second lens E2 has a positive optical power. Its object side S3 is a convex surface, and its image side S4 is a convex surface. The third lens E3 has a positive optical power. Its object side S5 is a convex surface, and its image side S6 is a convex surface. The fourth lens E4 has a positive optical power. Its object side S7 is a convex surface, and its image side S8 is a convex surface. The fifth lens E5 has a negative optical power. Its object side S9 is a concave surface, and its image side S10 is a concave surface. The filter IR has an object side S11 and an image side S12. The image-side protective glass CG has an object side S13 and an image side S14. Light from the object sequentially passes through the surfaces S1 to S14 and finally forms an image on the imaging surface S15.

[0079] Table 4 shows the surface types, curvature radii, thicknesses, and materials of the lenses of the optical imaging lens of Example 4. Among them, the units of the curvature radius and the thickness are both millimeters (mm).

[0080] Table 4

[0081]

[0082] Figure 8 Shows the axial chromatic aberration, astigmatism, and distortion curves of the optical imaging lens of Example 4. The axial chromatic aberration indicates that the focusing points of light rays of different wavelengths after passing through the lens deviate; the astigmatism indicates the curvature of the meridional image plane and the curvature of the sagittal image plane; the distortion indicates the distortion magnitude values corresponding to different image heights. The optical imaging lens given in Example 4 can achieve good imaging quality.

[0083] In Examples 1-4, the basic data are shown in Table 5 below:

[0084] Table 5

[0085]

[0086] In Examples 1-4, each conditional formula satisfies the conditions in Table 6 below:

[0087] Table 6

[0088]

[0089] A camera module includes at least an optical lens. The above-mentioned medical endoscope optical system is installed inside the optical lens, which has the characteristics of a small aperture and a large depth of field, and can ensure good imaging quality at the same time.

[0090] As described above, one or more implementation manners are provided in combination with specific content, and it is not determined that the specific implementation of the present invention is only limited to these descriptions. Any approximation, similarity, or several technical deductions or substitutions made under the premise of the concept of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A medical endoscope optical system, characterized in that: The optical axis includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens in sequence from the object plane to the image plane; The first lens has negative optical power, and its image side surface is concave; The second lens has positive refractive power, its object side surface is convex, and its image side surface is convex; The third lens has positive refractive power, its object side surface is convex, and its image side surface is convex; The fourth lens has positive refractive power, its object side surface is convex, and its image side surface is convex; The fifth lens element has negative optical power, and its object side surface is concave.

2. The medical endoscope optical system according to claim 1, characterized in that: The optical system satisfies the following relationship: 23.3<HFOV / (Fno*DT11)<27.0; Wherein, HFOV is half of the maximum field of view of the optical system, Fno is the F number of the optical system, and DT11 is the maximum effective radius of the object side of the first lens of the optical system.

3. The medical endoscope optical system according to claim 1, characterized in that: The optical system satisfies the following relationship: 3.4<TTL / (2*ImgH)<5.3; Wherein, TTL is the maximum axial distance from the inner surface of the effective light aperture on the object side of the first lens to the imaging surface, and ImagH is half of the diagonal length of the effective pixel area on the imaging surface.

4. The medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The optical system satisfies the following relationship: 1.1<f23 / f<2.1; Wherein, f23 is the combined focal length of the second lens and the third lens, and f is the effective focal length of the optical system.

5. The medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The optical system satisfies the following relationship: 3.1≤|(f2-f1) / f1|≤4.6; and / or 2.6<(f3+f4) / (f3-f4)<4.3; Wherein, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and f4 is the effective focal length of the fourth lens.

6. The medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The optical system satisfies the following relationship: 0.2<|R4 / R5|<2.3; and / or 1.6<|(R6+R7) / R7|<3.2; Among them, R4 is the curvature radius of the image side of the second lens, R5 is the curvature radius of the object side of the third lens, R6 is the curvature radius of the image side of the third lens, and R7 is the curvature radius of the object side of the fourth lens.

7. The medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The optical system satisfies the following relationship: 4.3≤CT2 / DT22≤8.6; Wherein, CT2 is the center thickness of the second lens on the optical axis, and DT22 is the maximum effective radius of the image side of the second lens.

8. The medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The optical system satisfies the following relationship: 8.1<DT41 / SAG7<13.8; Wherein, DT41 is the maximum effective radius of the fourth lens object side, and SAG7 is the distance from the maximum effective aperture of the fourth lens object side to the intersection of the fourth lens object side and the optical axis in the direction parallel to the optical axis.

9. The medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The F number of the optical system is less than 4.7, the full field of view angle FOV is greater than or equal to 90°, and the total length TTL of the lens is less than 3.8 mm.

10. A camera module, comprising at least an optical lens, characterized in that: The optical lens is equipped with the medical endoscope optical system according to any one of claims 1 to 9.

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