Zoom endoscope lens

Abstract

The zoom range of the zoom endoscope lens ranges from 4.8 mm to 14.1 mm, the zoom ratio is 2.9, the F number ranges from 4.3 to 5.9, the semi-field angle ranges from 12 degrees to 32 degrees, the total length of a lens system does not exceed 41 mm, the maximum aperture of all lenses is 7.6 mm, the image height is 6 mm, the zoom endoscope lens is composed of six spherical lens bodies and one aspherical lens body, and the zoom endoscope lens sequentially comprises a front fixing set, a diaphragm and a zoom set in the direction from the object side to the image side along the optical axis. The front fixed group comprises a first lens and a second lens, the zoom group comprises a third lens and a fourth lens, the compensation group comprises a fifth lens and a sixth lens, the rear fixed group comprises a seventh lens, the first lens is an aspheric lens, and the second lens to the seventh lens are spherical lenses; the zoom endoscope lens provided by the invention has the characteristics of high zoom ratio and small caliber, and can ensure good imaging quality during zooming.

Description

Technical Field

[0001] The present invention relates to the field of optical instruments, and in particular to a zoom endoscope lens, which is mainly used in the fields of medical treatment, industrial detection, etc. Background Art

[0002] In modern medical diagnosis and industrial inspection scenarios, the demand for high-quality zoom endoscope lenses is growing. Traditional endoscope lenses often have some limitations, such as limited focal range, unsatisfactory field of view, decreased image quality during zooming, and lens size and structure that are not suitable for complex usage environments. In the medical field, for delicate operations such as intracranial examinations, lenses that can clearly observe tiny lesions and can flexibly zoom are required; in the industrial field, for the inspection of narrow spaces inside complex machinery, zoom endoscope lenses with high resolution are also required. Existing technologies are difficult to simultaneously meet these diverse and demanding application scenarios. Therefore, the present invention aims to provide a zoom endoscope lens with better performance. Summary of the invention

[0003] In order to overcome the above technical problems, the present invention proposes a zoom endoscope lens, the zoom range of the lens is 4.8mm~14.1mm, the zoom ratio is 2.9, the F number is 4.3~5.9, and the half field angle is 12°~32°. The observation range can be increased and clear imaging can be maintained when observing the human body or the inside of a device. The total length of the lens system is less than 41mm, the maximum aperture of all lenses of the lens system is 7.6mm, and the image height is 6mm. It can reduce harm to patients in medical scenarios and reduce damage to the inside of devices in the industrial field. The zoom range is 4.8mm~14.1mm, and good imaging quality can be guaranteed when zooming. The application scenarios are suitable for medical, industrial inspection and other fields that require in-depth internal observation.

[0004] The technical solution of the present application is: a zoom endoscope lens, wherein the zoom range of the zoom endoscope lens is 4.8mm-14.1mm, the zoom ratio is 2.9, the F number is 4.3-5.9, the half field angle is 12°-32°, the total length of the optical system of the zoom endoscope lens does not exceed 41mm, the maximum aperture of all lenses is 7.6mm, and the image height is 6mm. The zoom endoscope lens is composed of six spherical lenses and one aspherical lens, and along the direction from the object side to the image side of the optical axis, it includes a front fixed group, an aperture, a zoom group, a compensation group, and a rear fixed group in sequence; wherein the front fixed group includes two lenses, namely the first lens and the second lens; the zoom group includes two lenses, namely the third lens and the fourth lens; the compensation group includes two lenses, namely the fifth lens and the sixth lens; the rear fixed group includes one lens, namely the seventh lens; During the zooming process of the zoom endoscope lens from the near focus position to the far focus position, the distance between the front fixed group and the zoom group decreases, and the distance between the compensation group and the rear fixed group increases. At the same time, the zoom endoscope lens satisfies the following relationship: 1.09<|(f*B) / (F*G)|<2.33; 0.33<|f*tan(w) / G|<2.92; 0.32<|F*tan(w) / B|<1.26; Among them, f is the effective focal length of the zoom endoscope lens, F is the aperture number of the zoom endoscope lens, w is the half field angle of the zoom endoscope lens, G is the half image height of the zoom endoscope lens, and B is the zoom ratio of the zoom endoscope lens.

[0005] Furthermore, the zoom endoscope lens satisfies the following relationship during the zoom process: 0.075<(Dmax*F) / (TTL*B)<0.223; 0.207<(f*F) / (TTL*B)<0.853; Wherein, Dmax is the maximum value of the effective full aperture of the zoom endoscope lens, TTL is the total length of the optical system of the zoom endoscope lens, f is the effective focal length of the zoom endoscope, F is the aperture number of the zoom endoscope lens, and B is the zoom ratio of the zoom endoscope lens.

[0006] Furthermore, the first lens included in the zoom endoscope lens is an aspherical lens, and the first to seventh lenses are arranged in sequence along the optical axis from the object side to the image side, and the optical focal lengths of the first to seventh lenses are negative, negative, positive, positive, negative, positive, and positive in sequence.

[0007] Furthermore, in the zoom endoscope lens along the optical axis from the object end to the image end, the first lens is a double concave lens, the second lens is a concave-convex lens with the convex surface facing the image end, the third lens is a plano-convex lens with the convex surface facing the image end, the fourth lens is a double convex lens, the fifth lens is a double concave lens, the sixth lens is a double convex lens, and the seventh lens is a double convex lens.

[0008] Furthermore, the zoom endoscope lens satisfies the following relationship: 3.216<|(f1+f2)*B / f|<8.79; 2.932<|(f2+f3)*B / f|<7.966; 5.652<|(f3+f4)*B / f|<16.385; Wherein f is the effective focal length of the zoom endoscope, f1 is the effective focal length of the front fixed group, f2 is the effective focal length of the zoom group, f3 is the effective focal length of the compensation group, f4 is the effective focal length of the rear fixed group, and B is the zoom ratio of the zoom endoscope head.

[0009] Furthermore, the first lens is an aspherical lens made of glass, and the second lens to the seventh lens are all spherical lenses made of glass.

[0010] Furthermore, the first lens is an aspheric biconcave lens made of glass, and the optical constants of the material used for the lens satisfy the following relationship: 1.59<nd1<1.6; 67<vd1<70; Wherein nd1 is the refractive index of the optical material used for the first lens of the zoom endoscope lens, and vd1 is the Abbe number of the optical material used for the first lens of the zoom endoscope lens.

[0011] The advantages of the present invention are: 1. By adjusting the relative movement mechanism of each lens group and the number of lenses in the lens group, the optical power of each lens is adjusted to meet the imaging requirements at different focal lengths, and the lens shape is optimized to reduce aberrations and improve imaging clarity, so that the zoom endoscope lens can achieve a zoom ratio of 2.9 times; 2. The F number of the zoom endoscope lens is 4.3-5.9, and the half field angle range is 12°-32°, which can increase the observation range and keep the image clear when observing the inside of the human body or device; 3. The total length of the zoom endoscope lens system is less than 41 mm, the maximum aperture of all lenses is 7.6 mm, and the image height is 6 mm, which ensures that harm to patients in the medical field is reduced, and damage to the inside of the device is reduced in the industrial field.

[0012] 4. The first lens of the zoom endoscope lens is an aspherical lens, which not only helps to correct the imaging quality of the lens, but also helps to shorten the diameter of the first lens, thereby shortening the volume and weight of the zoom endoscope lens.

[0013] System parameters achieved by the present invention: The F number of the zoom endoscope lens is 4.3~5.9, the half field of view angle is 12°~32°, the zoom range is 4.8mm~14.1mm, the multi-field diffraction transfer function is higher than 0.6 at 40lp / mm, the full field distortion is lower than 5%, and the diffuse spot radius is lower than 5.6um. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the optical system of the zoom endoscope of the first embodiment of the present application in the near focus; Figure 2 It is a schematic diagram of the structure of the optical system of the zoom endoscope of the first embodiment of the present application; Figure 3 is a multi-field diffraction transfer function diagram of the optical system of the zoom endoscope of the first embodiment of the present application at close focus; Figure 4 is a multi-field diffraction transfer function diagram of the optical system of the zoom endoscope of the first embodiment of the present application at a far focus; Figure 5 is a schematic diagram of distortion of the optical system of the zoom endoscope of the first embodiment of the present application at close focus; Figure 6 is a schematic diagram of the distortion of the optical system of the zoom endoscope of the first embodiment of the present application at a far focus; Figure 7 is a near-focus diffusion pattern of the optical system of the zoom endoscope of the first embodiment of the present application; Figure 8 This is the dispersion pattern of the optical system of the zoom endoscope according to the first embodiment of the present application at a far focus. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] In the present invention, the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0017] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0018] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0019] An embodiment of the present invention provides a zoom endoscope lens, which includes, in order from the object side to the image side of the optical axis: a front fixed group, a diaphragm fixed on the front surface of the third lens in the zoom group, a zoom group, a compensation group, and a rear fixed group, wherein the zoom group and the compensation group can move along the optical axis. The front fixed group and the compensation group are both lens groups with negative optical power, the zoom group and the rear fixed group are both lens groups with positive optical power, and the diaphragm is fixed on the front surface of the third lens in the zoom group.

[0020] In this way, by reasonably allocating the movement mode and optical focal length of the four lens groups, the zoom endoscope lens can achieve a zoom ratio of 2.9 times. The F number range of the zoom endoscope lens of the present invention is 4.3-5.9, and the half field angle is 12°-32°. It can increase the observation range and maintain clear imaging when observing the human body or the inside of the device. The total length of the lens system is less than 41mm, the maximum aperture of all lenses is 7.6mm, and the image height is 6mm. It can reduce harm to patients in medical scenarios and reduce damage to the inside of devices in the industrial field. The zoom range is 4.8mm-14.1mm, and the image quality can be guaranteed when zooming. The application scenario is suitable for medical, industrial detection and other fields that require in-depth internal observation. The multi-field diffraction transfer function is higher than 0.6 at 40lp / mm, the full field distortion is less than 5%, and the diffuse spot radius is less than 5.6um.

[0021] In the embodiment of the present invention, along the direction from the object side to the image side of the optical axis, the front fixed group includes: a first lens and a second lens in sequence. The first lens is a lens with negative optical power, and the second lens is a lens with negative optical power. With respect to the lens shape, along the direction from the object side to the image side of the optical axis, the first lens is a concave-concave lens, and the second lens is a concave-convex lens with the convex surface facing the image plane.

[0022] In the embodiment of the present invention, along the direction from the object side to the image side of the optical axis, the zoom group includes: a third lens and a fourth lens in sequence. The third lens is a lens with positive optical power, and the fourth lens is a lens with positive optical power. With respect to the lens shape, along the direction from the object side to the image side of the optical axis, the third lens is a plano-convex lens with the convex surface facing the image plane, and the fourth lens is a convex-convex lens.

[0023] In the embodiment of the present invention, along the direction from the object side to the image side of the optical axis, the compensation group includes: a fifth lens and a sixth lens in sequence. The fifth lens is a lens with negative optical power, and the sixth lens is a lens with positive optical power. With respect to the lens shape, along the direction from the object side to the image side of the optical axis, the fifth lens is a concave-concave lens, and the sixth lens is a convex-convex lens.

[0024] In the embodiment of the present invention, along the direction from the object side to the image side of the optical axis, the rear fixed group includes: a seventh lens. The seventh lens is a lens with positive optical power. With respect to the lens shape, along the direction from the object side to the image side of the optical axis, the seventh lens is a convex-convex lens.

[0025] The zoom endoscope lens disclosed in the present invention has six spherical lenses and one aspherical lens, wherein the first lens is an aspherical lens made of glass, and the second lens to the seventh lens are all spherical lenses made of glass.

[0026] like Figure 1 , Figure 2 As shown, Figure 1 To show the arrangement of the lenses when the zoom endoscope lens of the present application is in close focus, Figure 2 The arrangement of the lenses when the zoom endoscope lens is at a far focus; according to the optical axis, from the object end to the image end, it includes: a front fixed group G1, a zoom group G2, a compensation group G3, and a rear fixed group; the front fixed group G1 includes a first lens L1 and a second lens L2, wherein the first lens L1 is an aspherical lens; the zoom group G2 includes a third lens L3 and a fourth lens L4; the compensation group G3 includes a fifth lens L5 and a sixth lens L6, and the rear zoom group includes a seventh lens L7. Among them, S1 is the object end of the first lens, S2 is the image end of the first lens, S3 is the object end of the second lens, S4 is the image end of the second lens, S5 is the object end of the third lens, S6 is the image end of the third lens, S7 is the object end of the fourth lens, S8 is the image end of the fourth lens, S9 is the object end of the fifth lens, S10 is the image end of the fifth lens, S11 is the object end of the sixth lens, S12 is the image end of the sixth lens, S13 is the object end of the seventh lens, S14 is the image end of the seventh lens, wherein the aperture is fixed on the surface S5, and the dotted line on the right side of S14 is the image end. The distance between S4 and S5 is D1, the distance between S8 and S9 is D2, and the distance between S12 and S13 is D3; wherein, the values ​​of D1-D3 are variable.

[0027] In the zoom endoscope lens system, the distance between the front fixed group and the zoom group, the distance between the zoom group and the compensation group, and the distance between the compensation group and the rear fixed group are variable, that is, the distance between the front fixed group and the zoom group, the distance between the zoom group and the compensation group, and the distance between the compensation group and the rear fixed group change with the change of the focal length of the zoom endoscope lens. Specifically, the distance between the second lens and the third lens is variable, the distance between the fourth lens and the fifth lens is variable, and the distance between the sixth lens and the seventh lens is variable. The above distance refers to the straight-line distance between the centers of two adjacent lenses on the optical axis.

[0028] During the zooming process of the zoom endoscope lens from the near focus position to the far focus position, the distance between the front fixed group and the zoom group decreases, and the distance between the compensation group and the rear fixed group increases; the zoom endoscope lens satisfies the following relationship: 1.09<|(f*B) / (F*G)|<2.33; 0.33<|f*tan(w) / G|<2.92; 0.32<|F*tan(w) / B|<1.26; Among them, f is the effective focal length of the zoom endoscope lens, F is the aperture number of the zoom endoscope lens, w is the half field of view angle of the zoom endoscope lens, G is the half image height of the zoom endoscope lens, and B is the zoom ratio of the zoom endoscope lens, which ensures that the lens has a suitable field of view at different focal lengths to avoid the observation effect being affected by too narrow or too wide field of view; ensures a good balance between the amount of light input and the imaging quality; under different observation environments and target object conditions, a uniformly bright and clear image can be obtained, reducing the phenomenon of images being too dark, too bright or with reduced resolution due to light problems; at the same time, the optical performance of the lens at different focal lengths and field of view angles is further optimized to ensure the stability and high quality of imaging.

[0029] In addition, the zoom endoscope lens satisfies the following relationship during the zoom process: 0.075<(Dmax*F) / (TTL*B)<0.223; 0.207<(f*F) / (TTL*B)<0.853; Among them, Dmax is the maximum value of the effective full aperture of the zoom endoscope lens, TTL is the total length of the optical system of the zoom endoscope lens, f is the effective focal length of the zoom endoscope, F is the aperture number of the zoom endoscope lens, and B is the zoom ratio of the zoom endoscope lens. By adjusting the F number, total length, zoom ratio, aperture and focal length of the lens, the lens can be more compact in size, can penetrate deeper into the patient or device, and reduce damage to the patient or the device.

[0030] The first lens is a biconcave aspheric lens, the second lens is a convex-concave lens with the convex surface facing the image end, the third lens is a plano-convex lens with the convex surface facing the image end, the fourth lens is a biconvex lens, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a biconvex lens, and the aperture is fixed at the object end of the third lens.

[0031] The zoom endoscope satisfies the following relationship: 3.216<|(f1+f2)*B / f|<8.79; 2.932<|(f2+f3)*B / f|<7.966; 5.652<|(f3+f4)*B / f|<16.385; Wherein f is the effective focal length of the zoom endoscope, f1 is the effective focal length of the front fixed group of the zoom endoscope lens, f2 is the effective focal length of the zoom endoscope lens zoom group, f3 is the effective focal length of the zoom endoscope lens compensation group, f4 is the effective focal length of the rear fixed group of the zoom endoscope lens, and B is the zoom ratio of the zoom endoscope lens. Reasonable allocation of the focal length range of the lens group is conducive to improving the stability of the optical performance of the zoom endoscope during zooming and focusing, and at the same time improving the optical performance of the zoom endoscope.

[0032] In the zoom endoscope lens, the distance between any two adjacent lenses in the front fixed group, the zoom group, and the compensation group, and the distance between the rear fixed group and the image plane are fixed values, that is, the distance between any two adjacent lenses in the front fixed group, the zoom group, and the compensation group, and the distance between the rear fixed group and the image plane do not change with the change of the focal length of the zoom endoscope lens. Specifically, in the front fixed group, the distance between the first lens and the second lens is fixed. In the zoom group, the distance between the third lens and the fourth lens is fixed. In the compensation group, the distance between the fifth lens and the sixth lens is fixed. The distance between the rear fixed group and the image plane is fixed. The above distance refers to the straight-line distance between the centers of two adjacent lenses on the optical axis.

[0033] The zoom endoscope lens, the zoom group and the compensation group move along the optical axis between the object end and the image end, so that the zoom endoscope lens can be focused.

[0034] In this embodiment, when the near focus position of the zoom endoscope lens changes to the far focus position, the interval value D1 between the front fixed group and the zoom group, the interval value D2 between the zoom group and the compensation group, and the interval value D3 between the compensation group and the rear fixed group are shown in Table 1 below: Table 1

[0035] By adjusting the distance between lens groups, the focus response speed of the lens can be faster and the image quality can be more stable during the zooming process.

[0036] The data of the curvature radius R, thickness d, refractive index nd and Abbe number vd of the zoom endoscope lens in this embodiment are shown in Table 2 below: Table 2

[0037] As shown in Table 2, surface 1 is the front surface of the first lens, surface 2 is the back surface of the first lens, surface 3 is the front surface of the second lens, surface 4 is the back surface of the second lens, surface 5 is the front surface of the third lens, and the aperture is fixed on surface 5, surface 6 is the back surface of the third lens, surface 7 is the front surface of the fourth lens, surface 8 is the back surface of the fourth lens, surface 9 is the front surface of the fifth lens, surface 10 is the back surface of the fifth lens, surface 11 is the front surface of the sixth lens, surface 12 is the back surface of the sixth lens, surface 13 is the front surface of the seventh lens, and surface 14 is the back surface of the seventh lens.

[0038] In the zoom endoscope lens, the values ​​of the cone coefficient and the high-order aspheric coefficient of the first lens are shown in Table 3 below: Table 3

[0039] As shown in Table 3, assuming that the Z axis is the optical axis, the origin of the rectangular coordinate system (x, y, z) coincides with the origin of the aspheric surface, and the rotation axis coincides with the optical axis of the system, the surface shape of the aspheric surface can be expressed as:

[0040] in, is the incident height of the light on the aspheric surface, k is the cone coefficient, A2, A4, A6, ... are the high-order aspheric coefficients, and c is the curvature at the vertex of the aspheric surface. Z is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis O; c is the curvature at the optical axis O, c = 1 / R (that is, the paraxial curvature c is the reciprocal of the curvature radius R in Table 2); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 3 shows the high-order coefficients that can be used for each aspheric mirror surface in the embodiment.

[0041] The optical constants of the material used for the first lens satisfy the following conditional formula: 1.59<nd1<1.6; 67<vd1<70; Where nd1 is the refractive index of the optical material used for the first lens, and vd1 is the Abbe number of the optical material used for the first lens. Since the first lens is an aspherical lens made of glass, it not only helps to correct the imaging quality of the lens, but also helps to shorten the diameter of the first lens, thereby shortening the volume and weight of the zoom endoscope lens.

[0042] Figures 1 to 8 The following are the schematic diagrams of the zoom endoscope lens structure for near focus and far focus in this embodiment, the multi-field diffraction transfer function diagram, the distortion diagram, and the diffuse spot diagram. The multi-field diffraction transfer function is higher than 0.6 at 40lp / mm, the full field distortion is lower than 5%, and the diffuse spot radius is lower than 5.6um.

[0043] It can be seen that the zoom endoscope lens system according to the embodiment of the present invention can meet the requirement of low distortion of the system.

[0044] See also Figure 3 , Figure 4 , Figure 3 , Figure 4 : is a multi-field diffraction transfer function diagram of the zoom endoscope lens in the first embodiment at the near focus position and the far focus position, wherein the abscissa represents line pairs in mm, and the ordinate represents the value of the multi-field diffraction transfer function. Figure 3 In the figure, the meridional diffraction limit curve and the sagittal diffraction limit curve coincide with each other, the meridional curve and the sagittal curve of the 0.00 field of view coincide with each other, and the sagittal curve of the 0.5 field of view and the sagittal curve of the 0.75 field of view are relatively close. Figure 4 In the figure, the meridional diffraction limit curve and the sagittal diffraction limit curve coincide with each other. The meridional curve and sagittal curve of the 0.00 field of view are close to the sagittal curve of the 0.75 field of view. Figure 3 Figure 4 It can be seen that the multi-field diffraction transfer function value of this zoom endoscope lens is greater than 0.6 regardless of whether it is at the near focus position or the far focus position, indicating that the imaging quality of this zoom endoscope lens is good and the imaging quality remains stable at each zoom position; See also Figure 5 , Figure 6 , Figure 5 , Figure 6 : are distortion diagrams of the zoom endoscope lens in the first embodiment at the near focus position and the far focus position under defined visible light wavelengths, wherein the abscissa represents the distortion magnitude, and the ordinate represents the normalized field of view. Figure 5 , Figure 6 In the figure, the curves of the three color wavelengths overlap. Figure 5 , Figure 6 It can be seen that under the visible light wavelength, the distortion of this zoom endoscope lens is better than 5% whether it is at the near focus position or the far focus position, which means that the distortion of this zoom endoscope lens is well corrected.

[0045] See also Figure 7 , Figure 8 , Figure 7 , Figure 8 : is a diagram of the size of the diffused spot of the zoom endoscope lens in the first embodiment at the near focus position and the far focus position, wherein the abscissa represents the relative field of view, and the ordinate represents the spot size. Figure 7 , Figure 8 It can be seen that the diffuse spot radius of this zoom endoscope lens is less than 5.6um whether it is at the near focus position or the far focus position, which shows that the spot size of this zoom endoscope lens is well controlled.

[0046] The technical effect of the present application is a zoom endoscope lens, the total length of the optical system of the zoom endoscope lens is less than 41mm, the maximum aperture of the lens is 7.6mm, and the image height is 6mm. It can reduce harm to patients in medical scenarios and reduce damage to the inside of devices in industrial fields. The multi-field diffraction transfer function is greater than 0.6 at 40lp / mm, the diffusion spot radius is less than 5.6um, the distortion is less than 5%, the F number range is 4.3-5.9, and the half field angle is 12°-32°. It can increase the observation range and maintain clear imaging when observing the human body or the inside of a device. The zoom range is 4.8mm-14.1mm, the zoom ratio is 2.9, and good imaging quality performance can be guaranteed when zooming. The application scenarios are suitable for medical, industrial inspection and other fields that require in-depth internal observation.

[0047] The description of the embodiments of the specification should be combined with the corresponding drawings, which should be considered as part of the complete specification. In the above description of the embodiments, any reference to directions and orientations is only for the convenience of description and should not be construed as any limitation on the scope of protection of the present invention.

[0048] The description of the preferred embodiments may involve a combination of features, which may exist independently or in combination. The present invention is not particularly limited to the preferred embodiments. The description of the above embodiments is only used to help understand the optical lens of the present invention and its core design concept. At the same time, for those skilled in the art, according to the concept of the present invention, there may be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A zoom endoscope lens, characterized in that: The zoom range of the zoom endoscope lens is 4.8 mm to 14.1 mm, the zoom ratio is 2.9, the F number is 4.3 to 5.9, the half field angle is 12° to 32°, the total length of the optical system of the zoom endoscope lens does not exceed 41 mm, the maximum aperture of all lenses is 7.6 mm, and the image height is 6 mm. The zoom endoscope lens is composed of six spherical lenses and one aspherical lens, and includes: a front fixed group, an aperture, a zoom group, a compensation group, and a rear fixed group in sequence from the object side to the image side of the optical axis, wherein the front fixed group includes the first lens and the second lens, the zoom group includes the third lens and the fourth lens, the compensation group includes the fifth lens and the sixth lens, and the rear fixed group includes the seventh lens; In the zoom process from the near focus position to the far focus position, the distance between the front fixed group and the zoom group decreases, and the distance between the compensation group and the rear fixed group increases, and the relationship is satisfied: 1.09<|(f*B) / (F*G)|<2.33; 0.33<|f*tan(w) / G|<2.92; 0.32<|F*tan(w) / B|<1.26; Wherein, f is the effective focal length of the zoom endoscope lens, F is the aperture number of the zoom endoscope lens, w is the half field angle of the zoom endoscope lens, G is the half image height of the zoom endoscope lens, and B is the zoom ratio of the zoom endoscope lens; During the zoom process, the zoom endoscope lens also satisfies the following relationship: 0.075<(Dmax*F) / (TTL*B)<0.223; 0.207<(f*F) / (TTL*B)<0.853; Among them, Dmax is the maximum value of the effective full aperture of the zoom endoscope lens, and TTL is the total length of the optical system of the zoom endoscope lens.

2. The zoom endoscope lens according to claim 1, characterized in that: The first lens of the zoom endoscope lens is an aspherical lens, and the first to seventh lenses are arranged in sequence along the optical axis from the object side to the image side, and the optical power of the first to seventh lenses is negative, negative, positive, positive, negative, positive, and positive in sequence.

3. The zoom endoscope lens according to claim 1, characterized in that: The zoom endoscope lens is arranged along the optical axis from the object end to the image end, wherein the first lens is a biconcave lens, the second lens is a concave-convex lens with the convex surface facing the image end, the third lens is a plano-convex lens with the convex surface facing the image end, the fourth lens is a biconvex lens, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, and the seventh lens is a biconvex lens.

4. The zoom endoscope lens according to claim 1, characterized in that: The zoom endoscope satisfies the following relationship: 3.216<|(f1+f2)*B / f|<8.79; 2.932<|(f2+f3)*B / f|<7.966; 5.652<|(f3+f4)*B / f|<16.385; Among them, f1 is the effective focal length of the front fixed group, f2 is the effective focal length of the zoom group, f3 is the effective focal length of the compensation group, and f4 is the effective focal length of the rear fixed group.

5. The zoom endoscope lens according to claim 2, characterized in that: The first lens is an aspherical lens made of glass.

6. The zoom endoscope lens according to claim 2, characterized in that: The second lens to the seventh lens are all spherical lenses made of glass.

7. The zoom endoscope lens according to claim 2, characterized in that: The first lens is an aspheric biconcave lens made of glass, and the optical constants of the material used for the lens satisfy: 1.59<nd1<1.6; 67<vd1<70; Wherein, nd1 is the refractive index of the optical material used for the first lens for d-light, and vd1 is the Abbe number of the optical material used for the first lens for d-light.

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