Endoscope imaging system and endoscope

Abstract

The utility model discloses an endoscope imaging system and an endoscope. The endoscope imaging system sequentially comprises first window glass, a diaphragm, a lens subsystem, second window glass and a detection imaging element from an object side to an image side along an optical axis, the first window glass and the second window glass are used for protecting lenses in the lens subsystem; the detection imaging element is used for displaying an image formed by the lens subsystem; from the object side to the image side along the optical axis, the lens subsystem sequentially comprises a first lens group with positive focal power, a second lens group with positive focal power and a third lens group with negative focal power, the first lens group is used for focusing light; the second lens group and the third lens group have negative focal power, each of the second lens group and the third lens group comprises two lenses, and the two lenses are glued together; the second lens group and the third lens group are used for diverging light; the focal power of the fourth lens group is positive, and the fourth lens group comprises at least one lens; and the fourth lens group is used for focusing the light.

Description

Technical Field

[0001] The present application relates to the technical field of medical ultrasonic equipment, and in particular to an endoscopic imaging system and an endoscope. Background Art

[0002] Endoscopic imaging system is a commonly used medical device. Doctors can use the endoscopic imaging system to observe ulcers or tumors in the patient's body and develop the best treatment plan accordingly.

[0003] Among them, the camera optical system is an important component, which includes the optical adapter and the structure of the detector imaging surface. This is also the part that the doctor holds in his hand to perform surgical operations. It is also commonly called the handle. It is usually used with an external endoscope. There are already high-resolution 4K endoscopic imaging systems.

[0004] However, many endoscopic imaging systems in the industry currently have large handle structures, which is not conducive to doctors' operation. At the same time, the combination and shape of each lens in the existing imaging system are relatively simple, and the performance of the optical glass material is relatively backward, resulting in poor optical performance of the imaging system, inability to obtain clear images, and unable to meet the current high-definition picture display requirements. Utility Model Content

[0005] The purpose of the present application is to provide an endoscopic imaging system and an endoscope, so as to solve the problem that the existing imaging system has poor optical performance, cannot obtain clear images, and cannot meet the current high-definition picture display requirements.

[0006] In a first aspect, the present application provides an endoscopic imaging system, which includes, from the object side to the image side along the optical axis, a first window glass, an aperture, a lens subsystem, a second window glass, and a detection imaging element;

[0007] Wherein, the first window glass and the second window glass are used to protect the lens in the lens subsystem;

[0008] The detection imaging element is used to display the image formed by the lens subsystem;

[0009] The lens subsystem includes, in order from the object side to the image side along the optical axis:

[0010] A first lens group with positive optical power, wherein the first lens group includes at least one lens; the first lens group is used to focus light;

[0011] a second lens group with negative optical power, wherein the second lens group includes two lenses, and the two lenses are cemented together; the second lens group is used to diverge light; the object side surface of the first lens in the second lens group along the optical axis from the object side to the image side is a convex surface, and the image side surface of the second lens in the second lens group along the optical axis from the object side to the image side is a concave surface;

[0012] A third lens group with negative optical power, the third lens group comprising two lenses, the two lenses being cemented together; the third lens group is used to diverge light; the object side surface of the first lens in the third lens group along the optical axis from the object side to the image side is a concave surface, and the image side surface of the second lens in the third lens group along the optical axis from the object side to the image side is a convex surface;

[0013] A fourth lens group with positive optical power, wherein the fourth lens group comprises at least one lens; the fourth lens group is used for focusing light.

[0014] In a possible implementation, the first lens group includes two lenses, and the object-side surfaces of the two lenses are both convex surfaces, and the image-side surfaces of the two lenses are both concave surfaces.

[0015] In a possible implementation, the fourth lens group includes two lenses, and the object-side surfaces of the two lenses are both concave surfaces, and the image-side surfaces of the two lenses are both convex surfaces.

[0016] In a possible implementation manner, the distance between the object side surface of the first window glass and the image side surface of the detection imaging element is in the range of 27-33 mm.

[0017] In a possible implementation manner, the distance between the object side of the first window glass and the image side of the second window glass is in the range of 20-26 mm;

[0018] The distance between the aperture and the image side surface of the fourth lens group is in the range of 11-17 mm;

[0019] The sum of the distance between the image side surface of the first window glass and the aperture, and the distance between the image side surface of the fourth lens group and the object side surface of the second window glass is 7 mm;

[0020] The distance between the image side surface of the second window glass and the image side surface of the detection imaging element is 7 mm.

[0021] In a possible implementation, the first maximum effective aperture of at least one lens in the first lens group, the two lenses in the second lens group, and the two lenses in the third lens group are the same;

[0022] The second maximum effective aperture of at least one lens in the fourth lens group is consistent;

[0023] The first maximum effective aperture is smaller than the second maximum effective aperture.

[0024] In a possible implementation, the lenses in the first lens group, the second lens group, the third lens group, and the fourth lens group are all spherical lenses, and the centering coefficient of the spherical lenses is not less than 0.1.

[0025] In a possible implementation manner, the first lens group and the second lens group are symmetrical to the fourth lens group and the third lens group.

[0026] In a possible implementation manner, between the second window glass and the detection imaging element, further includes:

[0027] Infrared cut-off filter, used to filter the light beam;

[0028] The detector protection glass is used to protect the lens in the lens subsystem.

[0029] In a second aspect, the present application provides an endoscope, comprising an endoscopic imaging system as described in any one of the first aspects.

[0030] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0031] In the embodiment of the present application, the endoscope imaging system includes a first window glass, an aperture, a lens subsystem, a second window glass, and a detection imaging element in sequence from the object side to the image side along the optical axis; the first window glass and the second window glass are used to protect the lenses in the lens subsystem; the detection imaging element is used to display the image formed by the lens subsystem; the lens subsystem includes a first lens group with positive focal length, the first lens group includes at least one lens; the first lens group is used to focus the light; the second lens group and the third lens group are negative focal lengths, the second lens group and the third lens group each include two lenses, and the two lenses are glued together; the second lens group and the third lens group are used to diverge the light; the fourth lens group is positive focal length, the fourth lens group includes at least one lens; the fourth lens group is used to focus the light. Thus, the problem that the existing imaging system has poor optical performance, cannot obtain clear images, and cannot meet the current high-definition picture display requirements is solved.

[0032] Other features and advantages of the present application will be described in the subsequent description, and partly become apparent from the description, or be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings introduced below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 A schematic diagram of the structure of an endoscopic imaging system provided in an embodiment of the present application;

[0035] Figure 2 A schematic diagram of the structure of an endoscopic imaging system provided in an embodiment of the present application;

[0036] Figure 3 A schematic diagram of the structure of an endoscopic imaging system provided in an embodiment of the present application;

[0037] Figure 4 A schematic diagram of the structure of an endoscopic imaging system provided in an embodiment of the present application;

[0038] Figure 5 A schematic diagram of various distances in an endoscope imaging system provided in an embodiment of the present application;

[0039] Figure 6 A modulation transfer function diagram of an endoscopic imaging system provided in an embodiment of the present application;

[0040] Figure 7 A spot diagram of an endoscope imaging system provided by the present invention;

[0041] Figure 8 A field curvature diagram of an endoscope imaging system provided by the present invention;

[0042] Fig. 9 A distortion diagram of an endoscope imaging system provided by the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Among them, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0044] Furthermore, in the description of the embodiments of the present application, unless otherwise specified, “ / ” means or. For example, A / B can mean A or B. The “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0045] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more.

[0046] Endoscopic imaging system is a commonly used medical device. Doctors can use the endoscopic imaging system to observe ulcers or tumors in the patient's body and develop the best treatment plan accordingly.

[0047] Among them, the camera optical system is an important component, which includes the optical adapter and the structure of the detector imaging surface. This is also the part that the doctor holds in his hand to perform surgical operations. It is also commonly called the handle. It is usually used with an external endoscope. There are already high-resolution 4K endoscopic imaging systems.

[0048] However, many endoscopic imaging systems in the industry currently have large handle structures, which is not conducive to doctors' operation. At the same time, the combination and shape of each lens in the existing imaging system are relatively simple, and the performance of the optical glass material is relatively backward, resulting in poor optical performance of the imaging system, inability to obtain clear images, and unable to meet the current high-definition picture display requirements.

[0049] In view of this, the present application proposes an endoscopic imaging system and an endoscope to solve the problem that the existing imaging system has poor optical performance, cannot obtain clear images, and cannot meet the current high-definition picture display requirements.

[0050] The main concept of the present application can be summarized as follows: the endoscope imaging system in the embodiment of the present application includes a first window glass, an aperture, a lens subsystem, a second window glass, and a detection imaging element in sequence from the object side to the image side along the optical axis; the first window glass and the second window glass are used to protect the lenses in the lens subsystem; the detection imaging element is used to display the image formed by the lens subsystem; the lens subsystem includes a first lens group with positive focal length, the first lens group includes at least one lens; the first lens group is used to focus the light; the second lens group and the third lens group with negative focal length, the second lens group and the third lens group each include two lenses, and the two lenses are glued together; the second lens group and the third lens group are used to diverge the light; the fourth lens group with positive focal length, the fourth lens group includes at least one lens; the fourth lens group is used to focus the light. Thus, the problem that the existing imaging system has poor optical performance, cannot obtain clear images, and cannot meet the current high-definition picture display requirements is solved.

[0051] After introducing the main idea of ​​the embodiment of the present application, the endoscopic imaging system provided by the embodiment of the present application is introduced below with reference to the accompanying drawings.

[0052] An endoscope imaging system provided in an embodiment of the present application includes, from the object side to the image side along the optical axis, a first window glass, an aperture, a lens subsystem, a second window glass, and a detection imaging element;

[0053] Wherein, the first window glass and the second window glass are used to protect the lens in the lens subsystem;

[0054] A detection imaging element for displaying an image formed by the lens subsystem;

[0055] The lens subsystem includes the following components from the object side to the image side along the optical axis:

[0056] A first lens group with positive optical power, the first lens group includes at least one lens; the first lens group is used to focus light;

[0057] a second lens group with negative optical power, the second lens group including two lenses, the two lenses being cemented together; the second lens group is used to diverge light; the object side surface of the first lens in the second lens group along the optical axis from the object side to the image side is a convex surface, and the image side surface of the second lens in the second lens group along the optical axis from the object side to the image side is a concave surface;

[0058] a third lens group with negative optical power, the third lens group including two lenses, the two lenses being cemented together; the third lens group is used to diverge light; the object side surface of the first lens in the third lens group along the optical axis from the object side to the image side is a concave surface, and the image side surface of the second lens in the third lens group along the optical axis from the object side to the image side is a convex surface;

[0059] The fourth lens group has positive optical power and includes at least one lens; the fourth lens group is used for focusing light.

[0060] Embodiment 1: If the first lens group includes one lens, the object side surface of the lens is convex and the image side surface is concave; the second lens group and the third lens group each include two lenses; the fourth lens group includes one lens, the object side surface of the lens is concave and the image side surface is convex; then the structural schematic diagram of an endoscope imaging system provided in the embodiment of the present application is as follows Figure 1 shown.

[0061] like Figure 1 As shown, the endoscope imaging system provided in the embodiment of the present application includes a first window glass, an aperture, a lens subsystem, a second window glass, and a detection imaging element in sequence from the object side to the image side along the optical axis;

[0062] Wherein, the first window glass and the second window glass are used to protect the lens in the lens subsystem;

[0063] A detection imaging element for displaying an image formed by the lens subsystem;

[0064] The lens subsystem includes the following components from the object side to the image side along the optical axis:

[0065] a first lens group with positive optical power, the first lens group including a lens with a convex object side surface and a concave image side surface, for focusing light;

[0066] a second lens group with negative optical power, the second lens group including two lenses, the two lenses being cemented together; the second lens group is used to diverge light; the object side surface of the first lens in the second lens group along the optical axis from the object side to the image side is a convex surface, and the image side surface of the second lens in the second lens group along the optical axis from the object side to the image side is a concave surface;

[0067] a third lens group with negative optical power, the third lens group including two lenses, the two lenses being cemented together; the third lens group is used to diverge light; the object side surface of the first lens in the third lens group along the optical axis from the object side to the image side is a concave surface, and the image side surface of the second lens in the third lens group along the optical axis from the object side to the image side is a convex surface;

[0068] The fourth lens group has positive optical power and includes a lens with a concave object side surface and a convex image side surface, which is used to focus light.

[0069] In a possible implementation, the first lens group includes two lenses, and the object-side surfaces of the two lenses are both convex surfaces, and the image-side surfaces of the two lenses are both concave surfaces.

[0070] In a possible implementation, the fourth lens group includes two lenses, and both object-side surfaces of the two lenses are concave surfaces, and both image-side surfaces of the two lenses are convex surfaces.

[0071] Therefore, in embodiment 2: if the first lens group includes two lenses, the object side surfaces of the two lenses are both convex and the image side surfaces are both concave; the second lens group and the third lens group each include two lenses; the fourth lens group includes two lenses, the object side surfaces of the two lenses are both concave and the image side surfaces are both convex; then the structural schematic diagram of an endoscope imaging system provided in an embodiment of the present application is as follows Figure 2 shown.

[0072] like Figure 2 As shown, the endoscope imaging system provided in the embodiment of the present application includes a first window glass, an aperture, a lens subsystem, a second window glass, and a detection imaging element in sequence from the object side to the image side along the optical axis;

[0073] Wherein, the first window glass and the second window glass are used to protect the lens in the lens subsystem;

[0074] A detection imaging element for displaying an image formed by the lens subsystem;

[0075] The lens subsystem includes the following components from the object side to the image side along the optical axis:

[0076] A first lens group with positive optical power, the first lens group includes two lenses, both object side surfaces of the two lenses are convex and both image side surfaces are concave, for focusing light;

[0077] a second lens group with negative optical power, the second lens group including two lenses, the two lenses being cemented together; the second lens group is used to diverge light; the object side surface of the first lens in the second lens group along the optical axis from the object side to the image side is a convex surface, and the image side surface of the second lens in the second lens group along the optical axis from the object side to the image side is a concave surface;

[0078] a third lens group with negative optical power, the third lens group including two lenses, the two lenses being cemented together; the third lens group is used to diverge light; the object side surface of the first lens in the third lens group along the optical axis from the object side to the image side is a concave surface, and the image side surface of the second lens in the third lens group along the optical axis from the object side to the image side is a convex surface;

[0079] The fourth lens group has positive optical power and includes two lenses. The object side surfaces of the two lenses are both concave surfaces and the image side surfaces are both convex surfaces, and are used for focusing light.

[0080] In one possible implementation, Figure 1 and Figure 2 The first lens group and the second lens group are symmetrical to the fourth lens group and the third lens group.

[0081] For example, Figure 2 The eight lenses of the endoscope imaging system shown, including the first lens and the second lens of the first lens group, the first lens and the second lens of the second lens group, the first lens and the second lens of the fourth lens group, and the first lens and the second lens of the third lens group, form a symmetrical double-Gaussian structure. By adopting the double-Gaussian structure, various aberrations in the process of light propagation can be effectively balanced, so that the imaging system has the ability of high-resolution imaging and high imaging quality.

[0082] By utilizing four convex-concave single lenses with positive focal power at the front and rear and two convex-concave double-cemented lenses in the middle with negative focal power at the front and rear, the fixed-focus adapter in the endoscopic imaging system can be adapted to the needs of endoscopic imaging. While improving the optical imaging quality, the overall structure has the advantages of simple structure, short total optical length, small size, and easy installation and adjustment, making it more suitable for endoscopic imaging systems.

[0083] In a possible implementation, Figure 3 As shown, Figure 1 and Figure 2 Between the second window glass and the detection imaging element, there is also an infrared cut-off filter and a detector protection glass:

[0084] Infrared cut-off filter, used to filter the light beam;

[0085] Detector protection glass, used to protect the lens in the lens subsystem.

[0086] Therefore, combined with Figure 2 and Figure 3 The complete structure of the endoscopic imaging system provided in the embodiment of the present application is shown in FIG. Figure 4As shown. Wherein: 1 is the first window glass (including the object side surface S1 and the image side surface S2), 2 is the aperture, 3 is the first lens of the first lens group (including the object side surface S3 and the image side surface S4), 4 is the second lens of the first lens group (including the object side surface S5 and the image side surface S6), 5 is the first lens of the second lens group G1 (including the object side surface S7 and the image side surface S8), 6 is the second lens of the second lens group G1 (including the object side surface S8 and the image side surface S9), 7 is the first lens of the third lens group G2 (including the object side surface S10 and the image side surface S11). 8 is the second lens of the third lens group G2 (including the object-side surface S11 and the image-side surface S12), 9 is the first lens of the fourth lens group (including the object-side surface S13 and the image-side surface S14), 10 is the second lens of the fourth lens group (including the object-side surface S15 and the image-side surface S16), 11 is the second window glass (including the object-side surface S17 and the image-side surface S18), 12 is the infrared cutoff filter (including the object-side surface S19 and the image-side surface S20), 13 is the detector protection glass, and 14 is the detection imaging optical component.

[0087] The object light enters the endoscopic imaging system provided in the embodiment of the present application through the first window glass and the aperture, is coupled into the detector connection end of the second part through the spherical lens group optical system (fixed focus adapter optical structure) with optical focal length in the first part structure, and reaches the detection imaging optical component. Then the detection imaging optical component converts the optical signal into an electrical signal and sends it to the display for display.

[0088] In a possible implementation manner, the distance between the object side surface of the first window glass and the image side surface of the detection imaging element is in the range of 27-33 mm.

[0089] In a possible implementation, the distance between the object side of the first window glass and the image side of the second window glass is in the range of 20-26 mm;

[0090] The distance between the aperture and the image side of the fourth lens group ranges from 11 to 17 mm;

[0091] The sum of the distance between the image side surface of the first window glass and the aperture, and the distance between the image side surface of the fourth lens group and the object side surface of the second window glass is 7 mm;

[0092] The distance between the image side surface of the second window glass and the image side surface of the detection imaging element is 7 mm.

[0093] like Figure 5 FIG. 1 is a schematic diagram of various distances in the endoscope imaging system provided by the embodiment of the present application. The overall distance L1 between the object side of the first window glass and the image side of the detection imaging element of the endoscope imaging system is only 33 mm, making the overall structure relatively small.

[0094] Optional, such as Figure 5 As shown, the distance L2 between the object side surface of the first window glass and the image side surface of the second window glass in the direction of the optical axis is only 26 mm.

[0095] Optional, such as Figure 5 As shown, the total length of the spherical lens group optical system with optical focal length in the first part structure of the endoscopic imaging system, that is, the distance L4 between the aperture and the image side surface of the fourth lens group, is only 17 mm, and the endoscopic imaging system is basically completed by the spherical lens group optical system of the first part structure, and the spherical lens group optical system of the first part structure is an important component of the endoscopic imaging system.

[0096] Optional, such as Figure 5 As shown, in the first partial structure of the endoscope imaging system, the sum L3+L5 of the distance L3 between the image side surface of the first window glass and the aperture, and the distance L5 between the image side surface of the fourth lens group and the object side surface of the second window glass is 7 mm.

[0097] Each time the working distance of the endoscope imaging system is changed during use, it is necessary to adjust the focus to obtain a clear image, that is, the L4 part of the optical structure of the spherical lens group with optical power (the part between the aperture and the image side surface of the fourth lens group) can adjust the image clarity within the reserved 7mm range of L3+L5 that can be moved back and forth. Therefore, the sum of the distance L3 between the image side surface of the first window glass and the aperture in the first part structure, and the distance L5 between the image side surface of the fourth lens group and the object side surface of the second window glass is set to 7mm, which fully meets the use requirements and even has a margin. In addition, during the movement, the imaging quality will not be greatly affected and basically remains stable.

[0098] Optional, such as Figure 5 As shown, in the second part structure of the endoscope imaging system, the distance L6 between the image side of the second window glass and the image side of the detection imaging element is only 7 mm, so that the distance between the fixed focus adaptation to the detection imaging element part of the structure is relatively compact, and the mechanical connection structure of this part meets the IPX8 waterproof level requirement and can withstand disinfection.

[0099] In the spherical lens group optical system with optical focal length in the first part of the endoscope imaging system, after tolerance analysis, it was found that the tolerance of the second and third lens groups in the middle had the greatest impact on the imaging quality.

[0100] Therefore, in a possible implementation manner, in the present application, at least one lens in the first lens group, two lenses in the second lens group, and two lenses in the third lens group have the same first maximum effective aperture;

[0101] The second maximum effective aperture of at least one lens in the fourth lens group is consistent;

[0102] The first maximum effective aperture is smaller than the second maximum effective aperture.

[0103] like Figure 4 As shown, in the spherical lens group optical system with optical focal length of the first partial structure of the endoscopic imaging system, the maximum effective apertures of the first lens of the first lens group, the second lens of the first lens group, the first lens of the second lens group, the second lens of the second lens group, the first lens of the third lens group, and the second lens of the third lens group are all 7.4 mm; the maximum effective apertures of the first lens of the fourth lens group and the second lens of the fourth lens group are all 9.2 mm; the maximum effective apertures of the first lens of the first lens group, the second lens of the first lens group, the first lens of the second lens group, the second lens of the second lens group, the first lens of the third lens group, and the second lens of the third lens group are all smaller than the maximum effective apertures of the first lens of the fourth lens group and the second lens of the fourth lens group.

[0104] Therefore, the maximum effective apertures of the second lens group and the third lens group are made consistent and placed in the same lens barrel, so that the entire optical system has only two aperture values, reducing the tolerance effect of the structure at this location and improving the product yield. At the same time, the mechanical structure of the assembled optical system will be more regular, which is convenient for mechanical structure design.

[0105] It should be noted that when the requirements for edge width and step surface width during lens processing are met, the maximum effective aperture value in the embodiment of the present application can be adjusted up or down on this basis.

[0106] In addition, in the endoscope imaging system, in addition to the spherical lens group optical system with optical focal length, the maximum apertures of the three filters, namely the first window glass, the second window glass and the infrared cut-off filter, can be set to 10 mm.

[0107] In a possible implementation, the processing centering coefficient of a spherical optical lens reflects the difficulty of its processing. The larger the value, the easier it is to process. Therefore, in the embodiment of the present application, the lenses in the first lens group, the second lens group, the third lens group, and the fourth lens group are all spherical lenses, and the centering coefficient of the spherical lenses is not less than 0.1.

[0108] For example, Figure 4 In the spherical lens group optical system with optical focal length in the first part structure of the endoscopic imaging system shown, the centering coefficients of the eight spherical lenses are all ≥ 0.1, and they are all easy to process. Therefore, the parameter requirements for each optical lens can be better guaranteed on the basis of being able to be processed, which also means that the cost can be reduced.

[0109] In a possible implementation manner, the first window glass, the second window glass, and the infrared cut-off filter in the embodiment of the present application are all lenses with flat surfaces on both sides.

[0110] In a possible embodiment, the eight spherical lenses in the spherical lens group optical system with optical focal length of the first partial structure of the endoscopic imaging system: the first lens and the second lens of the first lens group, the first lens and the second lens of the second lens group, the first lens and the second lens of the fourth lens group, and the first lens and the second lens of the third lens group, all have optical focal length.

[0111] Among them, the four lenses in the front and rear of the fixed-focus adapter optical system, the first lens and the second lens of the first lens group, and the first lens and the second lens of the fourth lens group all have positive optical power, and can effectively converge light at the light incident end and the light exit end, respectively, that is, while ensuring the field of view angle, the length dimension of the entire system can be better compressed.

[0112] The second lens group including the first lens and the second lens and the third lens group including the first lens and the second lens both have negative optical power, diverge the light beam, and effectively balance the aberrations of the calibration system.

[0113] Among them, the focal length of the first lens of the first lens group is 24.14mm, the focal length of the second lens of the first lens group is 14.08mm, the focal length of the second lens group is -8.62mm, the focal length of the third lens group is -8.35mm, the focal length of the first lens of the fourth lens group is 20.93mm, and the focal length of the second lens of the fourth lens group is 15.90mm.

[0114] In a possible implementation, all plane lenses and front and back surfaces of spherical lenses with optical power in the first part of the structure of the endoscopic imaging system, which is a spherical lens group optical system with optical power (quasi-double Gaussian structure 4K fixed focus adapter), are coated with white light anti-reflection film. The spectral range of the coating of the infrared cutoff filter in the detector connection end of the second part is that white light passes, which effectively cuts off the infrared band light.

[0115] In a possible implementation, the field of view angle of the spherical lens group optical system with optical focal length (quasi-double Gaussian structure 4K fixed focus adapter) of the first part structure of the endoscopic imaging system is in the range of about 15°.

[0116] In a possible implementation, the entrance pupil diameter of the spherical lens group optical system with optical focal length (quasi-double Gaussian structure 4K fixed focus adapter) of the first partial structure of the endoscopic imaging system is in the range of 3.5 mm to 6.5 mm.

[0117] In the specific implementation process, the structural parameters of each lens of the endoscope imaging system in the embodiment of the present application are shown in Table 1. Wherein: Surf is the lens number, Radius is the curvature radius of the lens, Thickness is the distance from the nth lens to the n+1th lens, Semi-Diameter is the semi-aperture of the lens, Glass is the lens material, OBJ is the object plane, STO is the aperture, IMA is the image plane, and Infinity is infinity.

[0118] Table 1

[0119]

[0120]

[0121] It should be noted that the given parameter values ​​in Table 1 are only priority values, and the specific implementation includes but is not limited to the given parameter values ​​in Table 1.

[0122] The following further introduces the endoscope imaging system provided by the present embodiment by analyzing the optical system in detail. The modulation transfer function is a relatively accurate, intuitive and common method for evaluating the imaging quality of an optical system. The higher and smoother the curve is, the better the imaging quality of the system is, and various aberrations (such as spherical aberration, coma, astigmatism, field curvature, axial chromatic aberration, vertical axis chromatic aberration, etc.) are well corrected.

[0123] The endoscopic imaging system in the present application has high optical performance. In order to reduce the distortion of the endoscopic imaging system and improve the imaging quality of the system, the optical structure of the first part of the fixed-focus adapter is a quasi-double-Gaussian symmetrical structure that can self-correct aberrations.

[0124] like Figure 6 The figure shows a modulation transfer function diagram of an endoscope imaging system provided by an embodiment of the present application. Figure 6 It can be seen that the modulation transfer function (MTF) curve of the visible light part of the endoscope imaging system is relatively smooth and concentrated, and when the resolution of the endoscope imaging system meets 280lp / mm, the full-field modulation transfer function (MTF) value is greater than 0.2, and the entire field of view is close to the diffraction limit. It can be seen that the endoscope imaging system provided in this embodiment has a high resolution and good imaging quality, which meets the imaging requirements of 12 million pixels and 4K cameras.

[0125] like Figure 7 As shown, it is a point arrangement diagram of an endoscopic imaging system provided in an embodiment of the present application. Figure 7 The diffuse spots in the spot diagram of the endoscope imaging system are all smaller than the Airy disk, and the spot diameter is all included in the Airy disk.

[0126] like Figure 8 As shown in FIG. 1 , a field curvature diagram of an endoscope imaging system provided in an embodiment of the present application is shown. The field curvature diagram corresponding to the visible light part of the endoscope imaging system is composed of three solid curves and three dashed curves; Figure 8 As shown, the three solid curves represent the aberrations of the meridional beams (Tangential Rays) corresponding to the three wavelengths (0.5876μm, 0.6563μm and 0.4861μm) from left to right, and the three dotted curves represent the aberrations of the sagittal beams (Sagittial Rays) corresponding to the three wavelengths (0.5876μm, 0.6563μm and 0.4861μm) from left to right. The smaller the meridional field curvature value and the sagittal field curvature value are, the better the imaging quality is.

[0127] like Fig. 9 As shown in FIG. 1 , a distortion diagram of an endoscope imaging system provided in an embodiment of the present application is shown. The closer the curve is to the y-axis, the smaller the distortion rate is. Fig. 9 As shown, the distortion of the endoscopic imaging system provided in the embodiment of the present application is controlled within 0.8%.

[0128] Therefore, combined with Figure 6-9 According to the analysis, the endoscopic imaging system provided in the embodiment of the present application has the effects of low distortion and high imaging quality, and meets the requirements of 4K high-resolution imaging.

[0129] Based on the same concept, the present application also provides an endoscope, which includes an endoscopic imaging system as described in any of the above embodiments.

[0130] Since the endoscope in the embodiment of the present application includes the endoscope imaging system in the above-mentioned embodiment, the optical performance of the endoscope is improved, the imaging clarity is high, the resolution is high, and the high-definition picture display requirements are met. At the same time, the lens structure size is more miniaturized, which is convenient for the operator to use.

[0131] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present disclosure.

[0132] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to include these modifications and variations.

Claims

1. An endoscopic imaging system, characterized in that: The endoscope imaging system includes, from the object side to the image side along the optical axis, a first window glass, an aperture, a lens subsystem, a second window glass, and a detection imaging element in sequence; Wherein, the first window glass and the second window glass are used to protect the lens in the lens subsystem; The detection imaging element is used to display the image formed by the lens subsystem; The lens subsystem includes, in order from the object side to the image side along the optical axis: A first lens group with positive optical power, wherein the first lens group includes at least one lens; the first lens group is used to focus light; a second lens group with negative optical power, wherein the second lens group includes two lenses, and the two lenses are cemented together; the second lens group is used to diverge light; the object side surface of the first lens in the second lens group along the optical axis from the object side to the image side is a convex surface, and the image side surface of the second lens in the second lens group along the optical axis from the object side to the image side is a concave surface; A third lens group with negative optical power, the third lens group comprising two lenses, the two lenses being cemented together; the third lens group is used to diverge light; the object side surface of the first lens in the third lens group along the optical axis from the object side to the image side is a concave surface, and the image side surface of the second lens in the third lens group along the optical axis from the object side to the image side is a convex surface; A fourth lens group with positive optical power, wherein the fourth lens group comprises at least one lens; the fourth lens group is used for focusing light.

2. The endoscopic imaging system according to claim 1, characterized in that: The first lens group includes two lenses, and the object side surfaces of the two lenses are both convex surfaces, and the image side surfaces are both concave surfaces.

3. The endoscopic imaging system according to claim 1, characterized in that: The fourth lens group includes two lenses, both of which have concave object-side surfaces and convex image-side surfaces.

4. The endoscopic imaging system according to claim 1, characterized in that: The distance between the object side surface of the first window glass and the image side surface of the detection imaging element is in the range of 27-33 mm.

5. The endoscopic imaging system according to claim 4, characterized in that: The distance between the object side of the first window glass and the image side of the second window glass is in the range of 20-26 mm; The distance between the aperture and the image side surface of the fourth lens group is in the range of 11-17 mm; The sum of the distance between the image side surface of the first window glass and the aperture, and the distance between the image side surface of the fourth lens group and the object side surface of the second window glass is 7 mm; The distance between the image side surface of the second window glass and the image side surface of the detection imaging element is 7 mm.

6. The endoscopic imaging system according to claim 1, characterized in that: At least one lens in the first lens group, two lenses in the second lens group, and two lenses in the third lens group have the same first maximum effective aperture; The second maximum effective aperture of at least one lens in the fourth lens group is consistent; The first maximum effective aperture is smaller than the second maximum effective aperture.

7. The endoscopic imaging system according to claim 1, characterized in that: The lenses in the first lens group, the second lens group, the third lens group, and the fourth lens group are all spherical lenses, and the centering coefficient of the spherical lenses is not less than 0.

1.

8. The endoscopic imaging system according to claim 1, characterized in that: The first lens group and the second lens group are symmetrical to the fourth lens group and the third lens group.

9. The endoscopic imaging system according to claim 1, characterized in that: Between the second window glass and the detection imaging element, it also includes: Infrared cut-off filter, used to filter the light beam; The detector protection glass is used to protect the lens in the lens subsystem.

10. An endoscope, characterized in that: The endoscope comprises an endoscopic imaging system as described in any one of claims 1-9.

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