Miniature large-wide-angle medical endoscopic optical system and camera module applied by same

Abstract

The utility model provides a miniature wide-angle medical endoscopic optical system and a camera module using the same, the miniature wide-angle medical endoscopic optical system is composed of four lenses, the first lens has negative focal power, the object side surface of the first lens is a plane, and the image side surface of the first lens is a concave surface; the second lens has positive focal power, the object side surface of which is a convex surface and the image side surface of which is a concave surface, the third lens has positive focal power, the object side surface of which is a convex surface and the image side surface of which is also a convex surface, and the fourth lens has positive focal power, the object side surface of which is a convex surface or a concave surface and the image side surface of which is a concave surface or a convex surface, and has high pixel, large wide angle and small aperture; the optical system has the advantages of compact structure and large depth-of-field range, is convenient to process and install, and can increase the light incoming quantity and higher imaging quality of the optical system due to the configuration of the large aperture.

Description

Technical Field

[0001] The present application relates to the field of optical imaging, and in particular to a miniature wide-angle medical endoscopic optical system and a camera module used therein. Background Art

[0002] In recent years, with the rapid development of my country's economy, people's increasing pursuit of a better life has turned into the pursuit of daily health. The status of daily medical insurance in people's daily health has become increasingly important, and with the aging of the global population and the intensification of chronic diseases, people's demand and requirements for daily medical insurance have continued to increase. Among them, imaging medical diagnosis based on optical imaging system endoscopes has been widely concerned and applied by medical practitioners due to its non-invasive, painless detection, safe and reliable performance. The advance imaging medical acquisition of the patient's diseased organs through the lens is undoubtedly one of the prerequisites for alleviating patients' pain, reducing medical expenses, and saving time for seeing a doctor.

[0003] However, since medical endoscope lenses are mainly used in the human body with a very complex structural environment, the requirements for the endoscope camera are extremely high. Not only does it require a large field of view and a small aperture, but it also requires it to have good image capture performance and a large depth of field. At present, most medical lenses on the market generally use an imaging system composed of multiple glass and plastic materials in order to pursue a wide angle and good image capture performance. However, this will result in a large lens aperture and high cost, which is not conducive to the comfort of the human body during imaging diagnosis. In addition, with the increasing miniaturization of optoelectronic components and the diversification of human lesions, the market is in urgent need of manufacturing a medical endoscope optical lens with a small size, a large field of view, a low cost, and a wide depth of field. Utility Model Content

[0004] The present application aims to provide a large wide-angle and small-aperture medical endoscopy optical lens, which has the advantages of high pixels, large wide-angle and small aperture, and a large depth of field. It has a compact structure and is easy to process and install. At the same time, the configuration of a large aperture can increase the amount of light entering the optical system and achieve higher imaging quality.

[0005] A miniature wide-angle medical endoscope optical system includes a protective glass, a first lens, a second lens, an aperture, a third lens, and a fourth lens in sequence from the object plane to the image plane along the optical axis;

[0006] The first lens has negative optical power, its object side surface is a flat surface, and its image side surface is a concave surface;

[0007] The second lens has positive refractive power, its object side surface is convex, and its image side surface is concave;

[0008] The third lens has positive refractive power, its object side surface is convex, and its image side surface is also convex;

[0009] The fourth lens has a positive optical power, its object side is convex or concave, and its image side is concave or convex.

[0010] Preferably, the optical system satisfies the following relationship: 13.95° / mm 3 ≤ DFOV / (DT11*IamgD*TTL) ≤35.00° / mm 3 ;

[0011] Wherein, DFOV is the maximum field of view angle of the optical system, DT11 is the maximum effective clear aperture radius of the object side of the first lens, TTL is the on-axis distance from the object side of the protective glass to the imaging surface, and IamgD is half of the diagonal length of the effective pixel area on the imaging surface.

[0012] Preferably, the optical system satisfies the following relationship: 1.70° ≤ f*tan(DFOV) / DT11 ≤ 4.40°;

[0013] Wherein, f is the effective focal length of the optical system, DFOV is the maximum field of view angle of the optical system, and DT11 is the maximum effective clear aperture radius of the object side of the first lens.

[0014] Preferably, the optical system satisfies the following relationship:

[0015] 1.10 ≤ |(f1-f2)| / |(f1+f2)| ≤ 1.80;

[0016] 1.60 ≤ |(f3-f4)| / |(f3+f4)| ≤ 2.30;

[0017] 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.

[0018] Preferably, the optical system satisfies the following relationship:

[0019] -2.60 ≤ f3 / f+f4 / f ≤ -1.00;

[0020] -1.50 ≤ f / (f1+f2+f3+f4) ≤ 0.50;

[0021] 1.05 ≤ f / (f12+f23+f34) ≤ 1.70;

[0022] Among them, f is the effective focal length of the optical system, 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, f4 is the effective focal length of the fourth lens, f12 is the combined focal length of the first lens and the second lens, f23 is the combined focal length of the second lens and the third lens, and f34 is the combined focal length of the third lens and the fourth lens.

[0023] Preferably, the optical system satisfies the following relationship:

[0024] 3.80 ≤ TTL / f ≤ 6.20;

[0025] Among them, TTL is the total length of the optical system, and f is the effective focal length of the optical system.

[0026] Preferably, the optical system satisfies the following relationship:

[0027] 0.35 ≤ |(R1 + R2 + R3 + R4) / (R5 + R6 + R7 + R8)| ≤ 5.85;

[0028] 0.60 ≤ (CT1 + CT2) / f ≤ 2.00;

[0029] 3.00 ≤ TTL / (CT1 + CT2) ≤ 6.50;

[0030] Among them, R1 is the radius of curvature of the object side surface of the first lens, R2 is the radius of curvature of the image side surface of the first lens, R3 is the radius of curvature of the object side surface of the second lens, R4 is the radius of curvature of the image side surface of the second lens, R5 is the radius of curvature of the object side surface of the third lens, R6 is the radius of curvature of the image side surface of the third lens, R7 is the radius of curvature of the object side surface of the fourth lens, R8 is the radius of curvature of the image side surface of the fourth lens, CT1 is the central thickness of the first lens, CT2 is the central thickness of the second lens, TTL is the total length of the optical system, and f is the effective focal length of the optical system.

[0031] Preferably, the maximum effective clear aperture radius of the object side surface of the first lens ≤ 1.20 mm.

[0032] Preferably, the first lens, the second lens, the third lens, and the fourth lens are all aspherical plastic lenses.

[0033] Preferably, the total length of the optical system ≤ 4.10 mm, the full field of view angle of the optical system ≥ 140°, and the designed depth of field range is 3 - 60 mm.

[0034] On the other hand, the embodiment of the present application further provides an imaging module, which at least includes an optical lens, and the above-mentioned micro large-angle medical endoscope optical system is installed in the optical lens.

[0035] Compared with the prior art, the beneficial effects of the present application are as follows:

[0036] The present utility model provides a micro large-angle medical endoscope optical system and a camera module for its application, which is composed of 4 lenses. The first lens has a negative optical power, its object side is a plane, and its image side is a concave surface; the second lens has a positive optical power, its object side is a convex surface, and its image side is a concave surface. The third lens has a positive optical power, its object side is a convex surface, and its image side is also a convex surface. The fourth lens has a positive optical power, its object side is a convex surface or a concave surface, and its image side is a concave surface or a convex surface. It has the advantages of high pixel, large angle of view, small aperture, and large depth of field range. The structure is compact, which is convenient for processing and installation. At the same time, the configuration of a large aperture can increase the light input of the optical system and higher imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] Figure 1 It is a schematic structural diagram of the optical system or the camera module of Embodiment 1 of the present application;

[0039] Figure 2 It is a MTF curve and a MTF defocus curve diagram of the optical system or the camera module of Embodiment 1 of the present application;

[0040] Figure 3 It is a schematic structural diagram of the optical system or the camera module of Embodiment 2 of the present application;

[0041] Figure 4 It is a MTF curve and a MTF defocus curve diagram of the optical system or the camera module of Embodiment 2 of the present application;

[0042] Figure 5 It is a schematic structural diagram of the optical system or the camera module of Embodiment 3 of the present application;

[0043] Figure 6 It is a MTF curve and a MTF defocus curve diagram of the optical system or the camera module of Embodiment 3 of the present application;

[0044] Figure 7 It is a schematic structural diagram of the optical system or the camera module of Embodiment 4 of the present application;

[0045] Figure 8 It is a MTF curve and a MTF defocus curve diagram of the optical system or the camera module of Embodiment 4 of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] As Figure 1-8As shown in the figure, a miniature large wide-angle medical endoscope optical system includes, in sequence from the object side to the image side along the optical axis: an object image plane OBJ, a protective glass E0, a first lens E1, a second lens E2, a diaphragm plane STO, a third lens E3, a fourth lens E4, an infrared filter E5, a chip protective glass E6, and an imaging plane; the first lens, the second lens, the third lens, and the fourth lens are all aspherical plastic lenses. The first lens has a negative optical power, its object side is a plane, and its image side is a concave surface; the second lens has a positive optical power, its object side is a convex surface, and its image side is a concave surface; the third lens has a positive optical power, its object side is a convex surface, and its image side is also a convex surface; the fourth lens has a positive optical power, its object side is a convex surface or a concave surface, and its image side is a concave surface or a convex surface.

[0047] An embodiment of the present invention provides a miniature large wide-angle medical endoscope optical system, which is applied to the field of medical imaging. By using a combination of 4 plastic lenses, it realizes a large wide-angle range while also taking into account the resolution ability of the lens within a large depth of field, enabling it to better capture the detailed information of human lesion sites, so as to meet the needs of medical imaging practitioners for a medical endoscope with a large wide-angle, small aperture, and high-definition imaging within a large depth of field range. At the same time, it effectively reduces the pain of patients, reduces the medical expenses of patients, and saves the time for patients to see a doctor.

[0048] Furthermore, the optical system satisfies the following relationship: 13.95° / mm 3 ≤ DFOV / (DT11*IamgD*TTL) ≤ 35.00° / mm 3 ; where DFOV is the maximum field of view angle of the optical system, DT11 is the maximum effective clear aperture radius of the object side of the first lens, TTL is the axial distance from the object side of the protective glass to the imaging plane, and IamgD is half of the diagonal length of the effective pixel area on the imaging plane. This relational expression reflects the constraint situation of the optical lens in terms of the field of view angle and the thin and light characteristics, enabling the optical system to have good thin and light properties while meeting the wide-angle requirement, and ensuring that the optical system has the characteristics of ultra-wide angle, miniaturization, and thin and light. 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 ultra-wide, DT11*TTL*IamgD further increases, which will excessively compress the thin and light properties of the optical lens and is not conducive to the improvement of the performance 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.

[0049] Furthermore, the optical system satisfies the following relationship: 1.70° ≤ f * tan(DFOV) / DT11 ≤ 4.40°, where DFOV is the maximum field of view angle of the optical imaging system, f is the optical focal length of the medical endoscope optical imaging lens, and DT11 is the maximum effective clear aperture radius of the object side surface of the first lens. This relational expression reflects the constraint situation between the field of view angle of the optical lens and the lens spacing, which enables the optical system to have the characteristics of a small optical focal length while meeting the wide-angle requirement, ensuring that the lens has the characteristics of an ultra-wide angle and miniaturization. When above or below the upper and lower limits of the relational expression, on the basis of ensuring that the field of view angle of the optical lens is ultra-wide, DT11 will be further reduced, which will excessively compress the thickness of the optical lens and the air spacing between the lenses, being unfavorable for the processing of the lenses, and at the same time will also deteriorate the imaging resolution of the optical lens.

[0050] Furthermore, the optical system satisfies the following relationship: 1.10 ≤ |(f1 - f2)| / |(f1 + f2)| ≤ 1.80, where f1 is the effective focal length of the first lens and f2 is the effective focal length of the second lens. By adjusting the optical power of the first lens and the second lens, it is possible to avoid the excessive concentration of the optical power on the second lens, and at the same time it helps to constrain the surface shapes of the image side surface of the first lens and the second lens, avoiding excessive bending and affecting the processing manufacturability of the first lens and the second lens. In addition, satisfying the above relational expression can also reduce the tolerance sensitivity of the optical lens. When exceeding the lower limit of the relational expression, the optical power of the first lens is too concentrated, resulting in the excessive bending of the surface shape of the image side surface of the second lens, being unfavorable for the processing manufacturability of the first lens. When exceeding the upper limit of the relational expression, the optical power of the first lens is insufficient, being unfavorable for the correction of the aberrations of the optical lens and affecting the tolerance sensitivity of the optical lens.

[0051] Furthermore, the optical system satisfies the following relationship: 1.60 ≤ |(f3 - f4)| / |(f3 + f4)| ≤ 2.30, 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 power of the third lens and the fourth lens, it is possible to avoid the excessive concentration of the optical power on the fourth lens, and at the same time it helps to constrain the surface shapes of the third lens and the fourth lens. By controlling the ratio of the effective focal length of the third lens to the effective focal length of the fourth lens within a reasonable numerical range, it helps the light to transition smoothly, being favorable for correcting the chromatic aberration of the optical lens.

[0052] Further, the optical system satisfies the following relationship: -2.60 ≤ f3 / f + f4 / f ≤ -1.00, where f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, and f is the optical focal length of the single infrared industrial optical imaging lens. By controlling the ratios of the effective focal length of the third lens to the optical focal length of the optical lens and the effective focal length of the fourth lens to the optical focal length of the optical lens within a reasonable numerical range, it is beneficial for light to reach the imaging surface smoothly. At the same time, the distortion of the optical lens can be reduced, and the resolution quality of the optical lens can be improved.

[0053] Further, the optical system satisfies the following relationship: -1.50 ≤ f / (f1 + f2 + f3 + f4) ≤ 0.50, where f is the optical focal length of the medical endoscope optical imaging lens, 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. By restricting the ratio of the optical focal length of the medical endoscope optical imaging lens to the combined effective focal length of the first, second, third, and fourth lenses, the optical powers of the first, second, third, and fourth lenses can be properly distributed, enabling the fourth lens to have more diverse cooperation. Thus, on the basis of meeting the miniaturized design of the optical lens, the balance of the internal aberrations of the optical lens can be achieved, which further helps to adjust the field curvature of the imaging edge of the optical lens. At the same time, the distortion of the optical lens can be reduced, and the resolution quality of the optical lens can be improved.

[0054] Further, the optical system satisfies the following relationship: 1.05 ≤ f / (f12 + f23 + f34) ≤ 1.70, where f is the optical focal length of the medical endoscope optical imaging lens, f12 is the combined focal length of the first and second lenses, f23 is the combined focal length of the second and third lenses, and f34 is the combined focal length of the third and fourth lenses. By limiting the range of the above relationship, the front lens group (the first and second lenses) of the optical system provides positive refractive power, which is beneficial for large-angle light beams to pass through and enter, so as to achieve the wide-angle design of the optical system and is also beneficial for enhancing the brightness of the imaging surface of the optical system; while the rear lens group (the third and fourth lenses) of the optical system provides negative refractive power. On the one hand, it is beneficial to control the height of the light rays emerging from the optical system to reduce the high-order aberrations of the optical system and the outer diameters of the individual lenses in the rear lens group; on the other hand, it can correct the field curvature generated by the front lens group to reduce the impact on the resolution of the optical system and improve the imaging quality of the optical system.

[0055] Further, the optical system satisfies the following relationship: 3.80 ≤ TTL / f ≤ 6.20, where TTL is the total length of the imaging lens, and f is the effective optical focal length of the imaging lens. By constraining the ratio of the total length of the imaging lens to the effective optical focal length of the imaging lens, the distance between the first lens and the fourth lens can be reasonably set, effectively suppressing the phenomenon that the incident light beam is diverged and greatly expanded by the first lens and the second lens, without the need to excessively strengthen the converging effect of the lens groups of the third lens and the fourth lens on the image side. Therefore, it is possible to prevent the system from generating large aberrations, and effectively limit the length of the optical lens, which is beneficial to the miniaturization of the optical lens.

[0056] Further, the optical system satisfies the following relationship: 3.00 ≤ TTL / (CT1 + CT2) ≤ 6.50, where TTL is the total length of the imaging lens, CT1 is the central thickness of the first lens, and CT2 is the central thickness of the second lens. By constraining the ratio of the total length of the imaging lens to the sum of the central thicknesses of the individual lenses of the imaging lens, the overall length of the optical lens can be effectively constrained to meet the miniaturization requirements.

[0057] Further, the optical system satisfies the following relationship: 0.35 ≤ |(R1 + R2 + R3 + R4) / (R5 + R6 + R7 + R8)| ≤ 5.85, where R1 is the curvature radius of the object side of the first lens, R2 is the curvature radius of the image side of the first lens, R3 is the curvature radius of the object side of the second lens, 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, R7 is the curvature radius of the object side of the fourth lens, and R8 is the curvature radius of the image side of the fourth lens. By controlling the sum of the curvature radii of the object side and the image side of the first lens and the second lens and the difference between the sum of the curvature radii of the object side and the image side of the third lens and the fourth lens, the total deflection angle of the object side and the image side of the second lens at the marginal field of view can be reasonably controlled within a reasonable range, effectively reducing the sensitivity of the system, improving the lens yield, and at the same time being beneficial to reasonably controlling the bending degree of the third lens and the fourth lens, enabling them to have better processing and forming characteristics, and at the same time avoiding excessive deflection of light when transmitting between the lenses, reducing the processing difficulty of the optical lens group.

[0058] Furthermore, the optical system satisfies the following relationship: 0.60 ≤ (CT1 + CT2) / f ≤ 2.00, where CT1 is the central thickness of the first lens on the optical axis, and CT2 is the central thickness of the second lens on the optical axis. When the above conditional formula is satisfied, since the effective clear aperture radius of the lens and the thickness of the lens itself affect each other, by reasonably controlling the size of the effective clear aperture radius of the image side of the first lens, the central thickness of the second lens on the optical axis can be reasonably shortened, greatly reducing the volume of the overall lens group, which is beneficial to reducing the overall optical length of the optical system and reducing the risk of ghost images; exceeding the upper limit of the relational formula is not conducive to reducing the effective clear aperture radius of the image side of the first lens, affecting the smooth incidence of light on the second lens and increasing the risk of ghost images. Below the lower limit of the relational formula, the outer diameter of the first lens barrel part is too small, which will also cause the wall thickness of the lens barrel to be too thin, seriously affecting the strength and quality of the lens. If the outer diameter of the first lens barrel part ≤ 2.40 mm, the end area cannot be well reduced, which has an adverse effect on reducing the screen-to-body ratio.

[0059] Furthermore, the maximum effective clear aperture radius of the object side of the first lens ≤ 1.20 mm, the overall optical length of the optical system ≤ 4.10 mm, the full field of view angle of the optical system ≥ 140°, and the designed depth of field range is 3 - 60 mm. The large wide-angle and small-aperture medical endoscope optical imaging lens configured in the present invention has the advantages of high pixels, large wide-angle, small aperture, and large depth of field range. It has a compact structure, is convenient for processing and installation. At the same time, the configuration of a large aperture can increase the light input of the optical system and provide higher imaging quality.

[0060] Embodiment 1

[0061] Specifically, as a preferred implementation manner of the present invention rather than a limitation, 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.

[0062] As Figure 1 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: an object image plane OBJ, a protective glass E0, a first lens E1, a second lens E2, a stop plane STO, a third lens E3, a fourth lens E4, an infrared filter E5, a chip protective glass E6, and an imaging plane.

[0063] The object distance surface is S1; the protective glass E0 has an object side S2 and an image side S3; the first lens E1 has a negative optical power, its object side S4 is a plane, and its image side S5 is a concave surface; the second lens E2 has a positive optical power, its object side S6 is a convex surface, and its image side S7 is a concave surface; the third lens E3 has a positive optical power, its object side S9 is a convex surface, and its image side S10 is a convex surface; the fourth lens E4 has a negative optical power, its object side S11 is a convex surface, and its image side S12 is a concave surface; the filter E5 has an object side S13 and an image side S14; the chip protective glass E6 has an object side S15 and an image side S16, and the light from the object sequentially passes through the surfaces S1 to S16 and finally forms an image on the imaging surface S17.

[0064] Table 1 shows the surface types, curvature radii, thicknesses, and materials of the lenses of the optical imaging lens of Example 1, where the units of the curvature radius and thickness are both millimeters (mm).

[0065] Table 1

[0066]

[0067] In Table 1, the image side S4 of the first lens E1, the second lens E2, the third lens E3, and any one of the object side and the image side of the fourth lens E4 are all Q-type aspherical surfaces, and the surface shapes of the aspherical lenses can be defined by, but not limited to, the following aspherical formula:

[0068]

[0069] Among them, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the radial coordinate of the aspherical surface, c is the curvature of the aspherical surface vertex, K is the conic coefficient, Am is the aspherical coefficient, rmax is the maximum value of the radial radius coordinate, and u = r / rmax. Table 2 gives the conic coefficients and the high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 of the aspherical surfaces that can be used in the first embodiment.

[0070] Table 2

[0071]

[0072] Example Two

[0073] Specifically, as a preferred implementation manner of the present invention rather than a limitation, the following refers to Figures 3 to 4 Describe the optical imaging lens according to Embodiment 2 of the present application. Figure 3 Shows a schematic structural diagram of the optical imaging lens according to Embodiment 2 of the present application.

[0074] As Figure 3As shown in the figure, 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: an object image plane OBJ, a protective glass E0, a first lens E1, a second lens E2, a stop plane STO, a third lens E3, a fourth lens E4, an infrared filter E5, a chip protective glass E6, and an imaging plane.

[0075] The object distance plane is S1; the protective glass E0 has an object side S2 and an image side S3; the first lens E1 has a negative optical power, its object side S4 is a plane, and its image side S5 is a concave surface; the second lens E2 has a positive optical power, its object side S6 is a convex surface, and its image side S7 is a concave surface; the third lens E3 has a positive optical power, its object side S9 is a convex surface, and its image side S10 is a convex surface; the fourth lens E4 has a negative optical power, its object side S11 is a concave surface, and its image side S12 is a convex surface; the filter E5 has an object side S13 and an image side S14; the chip protective glass E6 has an object side S15 and an image side S16, and the light from the object sequentially passes through the surfaces S1 to S16 and finally forms an image on the imaging plane S17.

[0076] Table 3 shows the surface types, curvature radii, thicknesses, and materials of the lenses of the optical imaging lens of Example 2, where the units of the curvature radius and thickness are both millimeters (mm).

[0077] Table 3

[0078]

[0079] In Table 3, the image side S4 of the first lens E1, the second lens E2, the third lens E3, and any one of the object side and the image side of the fourth lens E4 are all Q-type aspherical surfaces. The surface shapes of the aspherical lenses can be defined by, but are not limited to, the following aspherical formula:

[0080]

[0081] Where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the radial coordinate of the aspherical surface, c is the curvature of the aspherical surface vertex, K is the conic coefficient, Am is the aspherical coefficient, rmax is the maximum value of the radial radius coordinate, and u = r / rmax. Table 4 gives the conic coefficients and the high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 of the aspherical surfaces that can be used in the second embodiment.

[0082] Table 4

[0083]

[0084] Example Three

[0085] Specifically, as a preferred embodiment of the present invention rather than a limitation, 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.

[0086] Specifically, as a preferred embodiment of the present invention rather than a limitation, as Figure 5 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: an object image plane OBJ, a protective glass E0, a first lens E1, a second lens E2, a stop plane STO, a third lens E3, a fourth lens E4, an infrared filter E5, a chip protective glass E6, and an imaging plane.

[0087] Specifically, as a preferred embodiment of the present invention rather than a limitation, the object distance plane is S1; the protective glass E0 has an object side S2 and an image side S3; the first lens E1 has a negative optical power, its object side S4 is a plane, and its image side S5 is a concave surface; the second lens E2 has a positive optical power, its object side S6 is a convex surface, and its image side S7 is a concave surface; the third lens E3 has a positive optical power, its object side S9 is a convex surface, and its image side S10 is a convex surface; the fourth lens E4 has a negative optical power, its object side S11 is a concave surface, and its image side S12 is a convex surface; the filter E5 has an object side S13 and an image side S14; the chip protective glass E6 has an object side S15 and an image side S16, and light from the object sequentially passes through surfaces S1 to S16 and finally forms an image on the imaging plane S17.

[0088] [4] Table 5 shows the surface type, curvature radius, thickness, and material of each lens of the optical imaging lens of Embodiment 3, where the units of the curvature radius and thickness are both millimeters (mm).

[0089] Table 5

[0090]

[0091] In Table 5, the image side S4 of the first lens E1, any one of the object side and the image side of the second lens E2, the third lens E3, and the fourth lens E4 are all Q-type aspherical surfaces, and the surface type of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0092]

[0093] Among them, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the radial coordinate of the aspherical surface, c is the curvature of the aspherical surface vertex, K is the conic coefficient, Am is the aspherical coefficient, rmax is the maximum value of the radial radius coordinate, and u = r / rmax. Table 6 gives the conic coefficients and the coefficients of higher-order terms A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 for each aspherical surface that can be used in the third embodiment.

[0094] Table 6

[0095]

[0096] Example 4

[0097] Specifically, as a preferred implementation manner of the present invention rather than a limitation, the following refers to Figures 7 to 8 Describe the optical imaging lens according to Embodiment 4 of the present application. Figure 7 The structural schematic diagram of the optical imaging lens according to Embodiment 4 of the present application is shown.

[0098] As Figure 7 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: an object image plane OBJ, a protective glass E0, a first lens E1, a second lens E2, a stop surface STO, a third lens E3, a fourth lens E4, an infrared filter E5, a chip protective glass E6, and an imaging surface.

[0099] The object distance surface is S1; the protective glass E0 has an object side surface S2 and an image side surface S3; the first lens E1 has a negative optical power, its object side surface S4 is a plane, and its image side surface S5 is a concave surface; the second lens E2 has a positive optical power, its object side surface S6 is a convex surface, and its image side surface S7 is a concave surface; the third lens E3 has a positive optical power, its object side surface S9 is a convex surface, and its image side surface S10 is a convex surface; the fourth lens E4 has a negative optical power, its object side surface S11 is a concave surface, and its image side surface S12 is a convex surface; the filter E5 has an object side surface S13 and an image side surface S14; the chip protective glass E6 has an object side surface S15 and an image side surface S16, and the light from the object sequentially passes through the surfaces S1 to S16 and finally forms an image on the imaging surface S17.

[0100] Table 7 shows the surface types, curvature radii, thicknesses, and materials of the lenses of the optical imaging lens in Embodiment 4, where the units of the curvature radius and the thickness are both millimeters (mm).

[0101] Table 7

[0102]

[0103] In Table 7, the image side S4 of the first lens E1, any one of the object side and the image side of the second lens E2, the third lens E3, and the fourth lens E4 are all Q-type aspherical surfaces. The surface shapes of the respective aspherical lenses can be defined by, but are not limited to, the following aspherical formula:

[0104]

[0105] Among them, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the radial coordinate of the aspherical surface, c is the curvature of the aspherical surface vertex, K is the conic coefficient, Am is the aspherical coefficient, rmax is the maximum value of the radial radius coordinate, and u = r / rmax. Table 8 gives the conic coefficients and the high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 of the respective aspherical surfaces that can be used in the fourth embodiment.

[0106] Table 8

[0107]

[0108] In Embodiments 1-4, the basic data is as follows:

[0109] Table 9

[0110]

[0111] In Embodiments 1-4, each conditional expression satisfies the conditions in the following table:

[0112] Table 10

[0113]

[0114] An imaging module includes at least an optical lens, and the above-mentioned miniature large-angle medical endoscope optical system is installed inside the optical lens. The miniature large-angle medical endoscope optical system configured in the present invention has the advantages of high pixels, large angle of view, small aperture, and large depth of field range. The structure is compact, which is convenient for processing and installation. At the same time, the configuration of a large aperture can increase the light input of the optical system and higher imaging quality.

[0115] As described above, one or more implementation manners are provided in combination with specific contents, and it is not determined that the specific implementation of the present utility model is only limited to these descriptions. Any approximation, similarity, or several technical deductions or replacements made under the premise of the concept of the present utility model should be regarded as the protection scope of the present utility model.

Claims

1. A miniature wide-angle medical endoscope optical system, characterized by: The optical axis includes a protective glass, a first lens, a second lens, an aperture, a third lens, and a fourth lens in sequence from the object plane to the image plane; The first lens has negative optical power, its object side surface is a flat surface, and its image side surface is a concave surface; The second lens has positive refractive power, its object side surface is convex, and its image side surface is concave; The third lens has positive refractive power, its object side surface is convex, and its image side surface is also convex; The fourth lens has positive refractive power, its object side surface is convex or concave, and its image side surface is concave or convex.

2. The miniature wide-angle medical endoscope optical system according to claim 1, characterized in that: The optical system satisfies the following relationship: 13.95° / mm 3 ≤ DFOV / (DT11*IamgD*TTL) ≤ 35.00° / mm 3 ; Wherein, DFOV is the maximum field of view of the optical system, DT11 is the maximum effective light transmission semi-aperture of the object side of the first lens, TTL is the axial distance from the object side of the protective glass to the imaging surface, and IamgD is half of the diagonal length of the effective pixel area on the imaging surface.

3. The miniature wide-angle medical endoscope optical system according to claim 1, characterized in that: The optical system satisfies the following relationship: 1.70° ≤ f*tan(DFOV) / DT11 ≤ 4.40°; Wherein, f is the effective focal length of the optical system, DFOV is the maximum field of view of the optical system, and DT11 is the maximum effective semi-aperture of the object side of the first lens.

4. The miniature wide-angle medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The optical system satisfies the following relationship: 1.10 ≤ |(f1-f2)| / |(f1+f2)| ≤ 1.80; and / or 1.60 ≤ |(f3-f4)| / |(f3+f4)| ≤ 2.30; Among them, 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.

5. The miniature wide-angle medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The optical system satisfies the following relationship: -2.60 ≤ f3 / f+f4 / f ≤ -1.00; and / or -1.50 ≤ f / (f1+f2+f3+f4) ≤ 0.50; and / or 1.05 ≤ f / (f12+f23+f34) ≤ 1.70; Among them, f is the effective focal length of the optical system, 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, f4 is the effective focal length of the fourth lens, f12 is the combined focal length of the first lens and the second lens, f23 is the combined focal length of the second lens and the third lens, and f34 is the combined focal length of the third lens and the fourth lens.

6. The miniature wide-angle medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The optical system satisfies the following relationship: 3.80 ≤ TTL / f ≤ 6.20; Wherein, TTL is the total length of the optical system, and f is the effective focal length of the optical system.

7. The miniature wide-angle medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The optical system satisfies the following relationship: 0.35 ≤ |(R1+R2+R3+R4) / (R5+R6+R7+R8)| ≤ 5.85; and / or 0.60 ≤ (CT1+CT2) / f ≤ 2.0; and / or 3.00 ≤ TTL / (CT1+CT2) ≤ 6.50; Among them, R1 is the curvature radius of the object side of the first lens, R2 is the curvature radius of the image side of the first lens, R3 is the curvature radius of the object side of the second lens, 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, R7 is the curvature radius of the object side of the fourth lens, R8 is the curvature radius of the image side of the fourth lens, CT1 is the center thickness of the first lens, CT2 is the center thickness of the second lens, TTL is the total length of the optical system, and f is the effective focal length of the optical system.

8. The miniature wide-angle medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The maximum effective semi-aperture of the first lens object side is ≤1.20mm; and / or The first lens, the second lens, the third lens and the fourth lens are all aspherical plastic lenses.

9. The miniature wide-angle medical endoscope optical system according to any one of claims 1 to 3, characterized in that: The total length of the optical system is ≤4.10mm, the full field of view of the optical system is ≥140°, and the designed depth of field range is 3-60mm.

10. A camera module, comprising at least an optical lens, characterized in that: The optical lens is equipped with a miniature wide-angle medical endoscopy optical system as described in any one of claims 1 to 9.

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