Optical lens, camera module, endoscope and endoscope system

Abstract

The application provides an optical lens, a camera module, an endoscope and an endoscope system. The optical lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged from an object side to an image side; the first lens has a negative focal power, the second lens has a negative focal power, the third lens has a positive focal power, and the fourth lens has a positive focal power; the third lens can move along the optical axis of the optical lens to focus the optical lens between a far focus and a near focus; the focal length f4 of the fourth lens of the optical lens and the focal length f2 of the second lens satisfy the relationship: -0.5 < f4 / f2 < -0.1. The optical lens achieves the purposes of large field of view, high image quality and miniaturization in the range of 2mm-100mm depth of field.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical imaging technology, and in particular to an optical lens, a camera module, an endoscope and an endoscope system. BACKGROUND

[0002] An electronic endoscope is a kind of tissue type that can be inserted into the human body, so that the doctor can directly observe the changes of the tissue type and lesions of the body cavity and internal organs of the human body, and make accurate diagnosis of diseases by using the electronic endoscope. At present, electronic endoscopes are widely used in various fields of clinical medicine, especially in the diagnosis of uterine cavity diseases, which have irreplaceable role.

[0003] For a camera module, such as an endoscope objective lens, it is usually used in cooperation with an endoscope to transmit the image detected by the endoscope to a detector, so as to facilitate better observation, and is commonly used in modern medical minimally invasive surgery and digestive tract examination and treatment.

[0004] In order to make precise diagnosis of lesions, it is expected that the endoscope has high resolution, which is beneficial to the doctor to better judge the lesions and improve the diagnosis efficiency; at the same time, it is also expected that the endoscope has a small size, that is, the aperture of the endoscope objective lens is small, which has obvious advantages in the field of non-narcotic minimally invasive diagnosis. How to develop an optical lens with large field of view, high image quality and miniaturization has become an important topic in the industry. SUMMARY

[0005] Embodiments of the present application provide an optical lens with large field of view, high image quality and miniaturization, a camera module, an endoscope and an endoscope system.

[0006] In a first aspect, embodiments of the present application provide an optical lens. The optical lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged from an object side to an image side; the first lens has a negative focal power, the second lens has a negative focal power, the third lens has a positive focal power, and the fourth lens has a positive focal power; the third lens can move along the optical axis of the optical lens to focus the optical lens between a far focus and a near focus; the focal length f4 of the fourth lens of the optical lens and the focal length f2 of the second lens satisfy the relationship: -0.5 < f4 / f2 < -0.1.

[0007] The optical lens provided by the embodiments of the present application has the beneficial effects that: by reasonably distributing the optical power of the optical lens, the optical power of the first lens and the second lens are both negative, when the light passes through each lens group of the optical lens, the light first passes through twice divergence and then passes through twice convergence, so that the transition of the light is relatively smooth, not only the aberration is reduced, the field of view and the resolution are improved, so that the imaging quality is improved, and the aperture of the optical lens is reduced. In addition, when the optical lens satisfies the above relationship, not only the aberration of the optical lens is well corrected, but also the total optical length of the optical lens is reduced, so that the optical lens achieves the purpose of considering large field of view, high image quality and miniaturization in the depth of field range.

[0008] In some embodiments, the fifth lens and the sixth lens form a cemented lens.

[0009] Through the above setting, not only the light passing through the optical lens is smoother, the tolerance sensitivity is reduced, and the imaging quality is further improved, but also the assembly of the optical lens is facilitated.

[0010] In some embodiments, the cemented lens has positive optical power.

[0011] Through the above setting, the cemented lens can well balance the first lens and the second lens, so that the transition of the light is smoother, not only the aberration is further reduced, but also the tolerance sensitivity is reduced, so that the imaging quality is further improved.

[0012] In some embodiments, the combined focal length fm of the cemented lens and the focal length f4 of the fourth lens satisfy the relationship: 0 < f4 / fm < 0.5.

[0013] By reasonable selection, when the optical lens satisfies the above relationship, not only the aberration of the optical lens is corrected, the imaging quality is improved, but also the total length of the optical lens is shortened.

[0014] In some embodiments, the combined focal length fm of the cemented lens and the effective focal length f of the optical lens at the telephoto position satisfy the relationship: 2 < fm / f < 50.

[0015] By reasonable selection, when the optical lens satisfies the above relationship, not only the imaging quality is further improved, but also the length of the optical lens is reduced.

[0016] In some embodiments, the focal length f1 of the first lens of the optical lens and the focal length f2 of the second lens satisfy the relationship: 0.1 < f2 / f1 < 0.4.

[0017] By reasonable selection, when the optical lens satisfies the above relationship, not only the imaging quality of the optical lens is further improved, but also the slimming of the optical lens is facilitated.

[0018] In some embodiments, a curvature radius R1 of the object side surface close to the object side of the second lens and a curvature radius R2 of the image side surface close to the image side satisfy a relationship: -1 < (R1-R2) / (R1+R2) < 3.

[0019] By reasonable selection, when the optical lens satisfies the above relationship, not only the size of the second lens in the direction perpendicular to the optical axis is effectively controlled, thereby shortening the size of the optical lens in the direction perpendicular to the optical axis, but also the thickness of the second lens is not too thin, which is easy to process.

[0020] In some embodiments, a focal length f3 of the third lens and an effective focal length f of the optical lens at the telephoto position satisfy a relationship: 2 < f3 / f < 8.

[0021] By reasonable selection, when the optical lens satisfies the above relationship, the aberrations of the third lens and the remaining lenses are mutually offset, the imaging quality is improved, and meanwhile, the length of the optical lens is shortened, thereby realizing the miniaturization design of the optical lens.

[0022] In some embodiments, the optical lens further comprises a diaphragm, which is located between the third lens and the fourth lens.

[0023] By the above arrangement, the optical lens structure is further symmetrical, and the imaging quality and the aperture size are taken into account.

[0024] In a second aspect, the embodiments of the present application further provide a camera module, which comprises the optical lens of the first aspect and a photosensitive element, and the photosensitive element is arranged on the image side of the optical lens.

[0025] The camera module in the embodiments of the present application has the same technical effects as the optical lens in the first aspect, and details are not repeated here.

[0026] In some embodiments, the optical lens further comprises a filter.

[0027] In some embodiments, the filter is an infrared cut-off filter.

[0028] By the above arrangement, the interference of infrared rays in the imaging process of the optical lens can be reduced, thereby further improving the imaging quality of the optical lens.

[0029] In some embodiments, the filter is provided with a laser cut-off film.

[0030] Through the above arrangement, the optical lens can be suitable for laser treatment.

[0031] In some embodiments, the photosensitive element is provided with a protective sheet.

[0032] Through the above arrangement, the photosensitive element can be well protected.

[0033] In a third aspect, the embodiments of the present application further provide an endoscope comprising the camera module of the second aspect.

[0034] The endoscope in the embodiments of the present application has the same technical effects as the camera module in the second aspect, and thus will not be described here.

[0035] In a fourth aspect, the embodiments of the present application further provide an endoscope system comprising a light source host, an image processing device, and the endoscope of the third aspect.

[0036] The camera module in the embodiments of the present application has the same technical effects as the endoscope in the third aspect, and thus will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0038] Figure 1 Structure optical path diagram of the optical lens in the first embodiment of the present application at a far focus;

[0039] Figure 2 Magnification chromatic aberration diagram of the optical lens in the first embodiment of the present application at a far focus;

[0040] Figure 3 Spherical aberration diagram of the optical lens in the first embodiment of the present application at a far focus;

[0041] Figure 4 Astigmatism diagram of the optical lens in the first embodiment of the present application at a far focus;

[0042] Figure 5 Distortion diagram of the optical lens in the first embodiment of the present application at a far focus;

[0043] Figure 6 Structure optical path diagram of the optical lens in the first embodiment of the present application at a near focus;

[0044] Figure 7Figure 9 is a lateral chromatic aberration graph of the optical lens in Example One of the present application at close focus;

[0045] Figure 8 Figure 10 is a spherical aberration graph of the optical lens in Example One of the present application at close focus;

[0046] Figure 9 Figure 11 is an astigmatism graph of the optical lens in Example One of the present application at close focus;

[0047] Figure 10 Figure 12 is a distortion graph of the optical lens in Example One of the present application at close focus;

[0048] Figure 11 Figure 13 is a structural schematic view of the optical lens in Example Two of the present application at far focus;

[0049] Figure 12 Figure 14 is a lateral chromatic aberration graph of the optical lens in Example Two of the present application at far focus;

[0050] Figure 13 Figure 15 is a spherical aberration graph of the optical lens in Example Two of the present application at far focus;

[0051] Figure 14 Figure 16 is an astigmatism graph of the optical lens in Example Two of the present application at far focus;

[0052] Figure 15 Figure 17 is a distortion graph of the optical lens in Example Two of the present application at far focus;

[0053] Figure 16 Figure 18 is a structural schematic view of the optical lens in Example Two of the present application at close focus;

[0054] Figure 17 Figure 19 is a lateral chromatic aberration graph of the optical lens in Example Two of the present application at close focus;

[0055] Figure 18 Figure 20 is a spherical aberration graph of the optical lens in Example Two of the present application at close focus;

[0056] Figure 19 Figure 21 is an astigmatism graph of the optical lens in Example Two of the present application at close focus;

[0057] Figure 20 Figure 22 is a distortion graph of the optical lens in Example Two of the present application at close focus;

[0058] Figure 21 Figure 23 is a structural schematic view of the optical lens in Example Three of the present application at far focus;

[0059] Figure 22 Figure 24 is a lateral chromatic aberration graph of the optical lens in Example Three of the present application at far focus;

[0060] Figure 23 A spherical aberration graph of the optical lens in Embodiment Three of the present application at a far focus;

[0061] Figure 24 A coma graph of the optical lens in Embodiment Three of the present application at a far focus;

[0062] Figure 25 A distortion graph of the optical lens in Embodiment Three of the present application at a far focus;

[0063] Figure 26 A structural schematic diagram of the optical lens in Embodiment Three of the present application at a near focus;

[0064] Figure 27 A lateral chromatic aberration graph of the optical lens in Embodiment Three of the present application at a near focus;

[0065] Figure 28 A spherical aberration graph of the optical lens in Embodiment Three of the present application at a near focus;

[0066] Figure 29 A coma graph of the optical lens in Embodiment Three of the present application at a near focus;

[0067] Figure 30 A distortion graph of the optical lens in Embodiment Three of the present application at a near focus;

[0068] Figure 31 A structural schematic diagram of the optical lens in Embodiment Four of the present application at a far focus;

[0069] Figure 32 A lateral chromatic aberration graph of the optical lens in Embodiment Four of the present application at a far focus;

[0070] Figure 33 A spherical aberration graph of the optical lens in Embodiment Four of the present application at a far focus;

[0071] Figure 34 A coma graph of the optical lens in Embodiment Four of the present application at a far focus;

[0072] Figure 35 A distortion graph of the optical lens in Embodiment Four of the present application at a far focus;

[0073] Figure 36 A structural schematic diagram of the optical lens in Embodiment Four of the present application at a near focus;

[0074] Figure 37 A lateral chromatic aberration graph of the optical lens in Embodiment Four of the present application at a near focus;

[0075] Figure 38 A spherical aberration graph of the optical lens in Embodiment Four of the present application at a near focus;

[0076] Figure 39 Distortion map of the optical lens in Example Four of the present application at close focus;

[0077] Figure 40 Distortion map of the optical lens in Example Four of the present application at close focus;

[0078] Figure 41 Structural schematic view of the optical lens in Example Five of the present application at far focus;

[0079] Figure 42 Ratios of chromatic spherical aberration map of the optical lens in Example Five of the present application at far focus;

[0080] Figure 43 Spherical aberration map of the optical lens in Example Five of the present application at far focus;

[0081] Figure 44 Astigmatism map of the optical lens in Example Five of the present application at far focus;

[0082] Figure 45 Distortion map of the optical lens in Example Five of the present application at far focus;

[0083] Figure 46 Structural schematic view of the optical lens in Example Five of the present application at close focus;

[0084] Figure 47 Ratios of chromatic spherical aberration map of the optical lens in Example Five of the present application at close focus;

[0085] Figure 48 Spherical aberration map of the optical lens in Example Five of the present application at close focus;

[0086] Figure 49 Astigmatism map of the optical lens in Example Five of the present application at close focus;

[0087] Figure 50 Distortion map of the optical lens in Example Five of the present application at close focus;

[0088] Figure 51 Structural schematic view of the optical lens in Example Six of the present application at far focus;

[0089] Figure 52 Ratios of chromatic spherical aberration map of the optical lens in Example Six of the present application at far focus;

[0090] Figure 53 Spherical aberration map of the optical lens in Example Six of the present application at far focus;

[0091] Figure 54 Astigmatism map of the optical lens in Example Six of the present application at far focus;

[0092] Figure 55 Distortion curve of the optical lens in embodiment six of the present application at far focus;

[0093] Figure 56 Structure diagram of the optical lens in embodiment six of the present application at near focus;

[0094] Figure 57 Ratios of chromatic spherical aberration curve of the optical lens in embodiment six of the present application at near focus;

[0095] Figure 58 Spherical aberration curve of the optical lens in embodiment six of the present application at near focus;

[0096] Figure 59 Astigmatism curve of the optical lens in embodiment six of the present application at near focus;

[0097] Figure 60 Distortion curve of the optical lens in embodiment six of the present application at near focus;

[0098] Figure 61 Structure diagram of the optical lens in embodiment seven of the present application at far focus;

[0099] Figure 62 Ratios of chromatic spherical aberration curve of the optical lens in embodiment seven of the present application at far focus;

[0100] Figure 63 Spherical aberration curve of the optical lens in embodiment seven of the present application at far focus;

[0101] Figure 64 Astigmatism curve of the optical lens in embodiment seven of the present application at far focus;

[0102] Figure 65 Distortion curve of the optical lens in embodiment seven of the present application at far focus;

[0103] Figure 66 Structure diagram of the optical lens in embodiment seven of the present application at near focus;

[0104] Figure 67 Ratios of chromatic spherical aberration curve of the optical lens in embodiment seven of the present application at near focus;

[0105] Figure 68 Spherical aberration curve of the optical lens in embodiment seven of the present application at near focus;

[0106] Figure 69 Astigmatism curve of the optical lens in embodiment seven of the present application at near focus;

[0107] Figure 70Distortion chart of the optical lens in Example Seven of the present application at close focus.

[0108] In the drawings, reference numerals:

[0109] First lens L1; second lens L2; third lens L3; fourth lens L4; fifth lens L5; sixth lens L6; filter L7; protective sheet L8; diaphragm STO. DETAILED DESCRIPTION

[0110] For the convenience of understanding, the English abbreviations and related technical terms involved in the embodiments of the present application are explained and described below.

[0111] Focal power, equal to the difference between the convergence degree of the image-side beam and the convergence degree of the object-side beam, which represents the ability of the optical lens to deflect light.

[0112] Lens or lens group with positive focal power, which has a positive focal length and has the effect of converging light.

[0113] Lens or lens group with negative focal power, which has a negative focal length and has the effect of diverging light.

[0114] Focal length F, also known as focal length, is a measure of the convergence or divergence of light in an optical lens, which refers to the vertical distance from the optical center of the lens or lens group to the focal plane when an infinite distant object forms a clear image through the lens or lens group. From a practical point of view, it can be understood as the distance from the lens center to the plane when the object is at infinity. For a fixed focus lens, the position of the optical center is fixed; for a long focus lens, the change of the optical center of the lens brings the change of the focal length of the lens.

[0115] Back focal length FBL, the length from the last end of the optical lens to the imaging plane.

[0116] Total track length TTL, which refers to the distance from the center of the lens to the focus of light convergence, that is, in the module, the distance from the center of the lens to the imaging plane of the Sensor surface.

[0117] Object side, with the lens as the boundary, the side where the object is located is the object side, and the surface of the lens close to the object side is called the object side.

[0118] Image side, with the lens as the boundary, the side where the image of the object is located is the image side, and the surface of the lens close to the image side is called the image side.

[0119] Apertured diaphragm, which is a device used to control the amount of light that enters the body through the lens and reaches the light-sensitive surface, which is usually inside the lens.

[0120] F number, also known as F number (FNO), is the relative value (the reciprocal of the relative aperture) of the focal length of the lens / the diameter of the lens entrance pupil. The smaller the F number, the more light enters in the same unit of time. The larger the F number, the smaller the depth of field, and the background content of the photograph will be blurred, similar to the effect of a long focal length lens.

[0121] Total track length (TTL) refers to the total length from the surface closest to the object side of the lens to the imaging surface. TTL is a major factor in determining the height of the camera.

[0122] Imaging surface, located on the image side of all lenses in the optical lens, and the carrier surface on which the light passes through each lens in the optical lens to form an image.

[0123] Optical axis is an axis that passes vertically through the center of the lens. The optical axis of the lens is the axis that passes through the center of each lens in the lens. When parallel light enters a convex lens, the ideal convex lens should converge all light rays to a point behind the lens. This point where all light rays converge is called the focal point.

[0124] Focal point, the converging point of parallel light after refraction through a lens or lens group.

[0125] Aberration: An optical lens has the properties of an ideal optical system at the optical axis. A point on the object emits light near the axis, which intersects at a point (i.e. the optical axis image point) on the image plane. However, the light passing through different apertures of the lens is difficult to perfectly intersect at a point, and there is a certain deviation from the position of the near-axis image point. These differences are collectively referred to as aberration.

[0126] Spherical aberration: Generally, the light rays of a spherical lens are more likely to produce severe refraction and curvature at the edge than at the center when entering the lens to the focal plane. This phenomenon leads to a decrease in sharpness and contrast and the generation of light spots, resulting in a decrease in image quality. The larger the aperture, the more severe the problem. Therefore, the use of a light collection aperture can improve this situation, but it cannot completely eliminate it. This type of aberration caused by spherical lenses is called spherical aberration.

[0127] Distortion, also known as distortion, is the degree of distortion of the image formed by an optical lens relative to the object itself. Distortion is caused by the effect of the diaphragm spherical aberration. The intersection height of the chief ray of different fields of view after passing through the optical lens is not equal to the ideal image height, and the difference between the two is the distortion. Therefore, distortion only changes the imaging position of the off-axis object point on the ideal surface, causing the shape of the image to be distorted, but does not affect the sharpness of the image.

[0128] Astigmatism, due to the object point not on the optical axis of the lens, the light beam emitted by it has an angle of inclination with the optical axis. After refraction through the lens, the meridional pencil and sagittal pencil of rays do not converge at a point. That is, the light beam cannot be focused to a point, the image is not clear, so it produces astigmatism. Meridional pencil and sagittal pencil of rays are two perpendicular planes in the rotationally symmetric optical lens.

[0129] Meridian plane, the plane formed by the principal ray (principal pencil of rays) of the object point outside the optical axis and the optical axis is called the meridian plane.

[0130] Sagittal surface, the plane passing through the principal ray (principal pencil of rays) of the object point outside the optical axis and perpendicular to the meridian plane is called the sagittal surface.

[0131] Curvature of field, the curvature of field is used to represent the difference between the position of the most clear image point of the non-central field of view and the position of the most clear image point of the central field of view after the light rays pass through the optical lens group. When the lens has field curvature, the intersection of the entire light beam does not coincide with the ideal image point, although a clear image point can be obtained at each specific point, but the entire image plane is a curved surface.

[0132] Lateral chromatic aberration, a kind of chromatic aberration caused by the difference in image height (i.e. magnification) of different color light.

[0133] Glued lens, also known as glued lens, refers to a combination lens composed of two or more lenses by gluing. The tolerance sensitivity of the glued lens is better than that of a single lens, and when applied to an endoscope product, it is more conducive to the assembly of the lens structure, and can improve the imaging quality of the endoscope.

[0134] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0135] The terms "first", "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise stated, the meaning of "multiple" is two or more.

[0136] An electronic endoscope is a kind of tissue type that can be inserted into the human body, so that the doctor can directly observe the tissue type and lesion changes of the body cavity and internal organs of the human body, and make accurate diagnosis of diseases by using the electronic endoscope. At present, electronic endoscopes are widely used in various fields of clinical medicine, especially in the diagnosis of uterine cavity diseases, which have irreplaceable role.

[0137] For camera modules, such as endoscope objectives, they are usually used in cooperation with endoscopes to transfer the images detected by the endoscopes to the detector for better observation, and are commonly used in modern medical minimally invasive surgery and digestive tract examination and treatment.

[0138] In order to make precise diagnosis of lesions, it is expected that the endoscope has good imaging quality, which is conducive to the doctor's better judgment of the lesion and improves the diagnosis efficiency, and at the same time, it is also expected that the endoscope has a wider field of view, which improves the observation range of the doctor and is conducive to shortening the examination time. How to develop an optical lens with a large field of view, high image quality and miniaturization has become an important topic in the industry.

[0139] In order to solve the above technical problems, the embodiment of the present application provides an optical lens and a camera module.

[0140] As shown in Figure 1 , the camera module includes an optical lens and a photosensitive element (IMAGE in Figure 1 , and the photosensitive element is located on the image side of the optical lens.

[0141] The working principle of the camera module is that the light reflected by the photographed object passes through the optical lens to generate an optical image projected to the photosensitive surface of the photosensitive element, and the photosensitive element converts the optical image into an electrical signal, i.e. an analog image signal, and transmits it to the processor.

[0142] Among them, the photosensitive element (also known as an image sensor) is a kind of semiconductor chip, and the surface contains hundreds of thousands to millions of photodiodes. When exposed to light, it will generate electric charge. The photosensitive element can be a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). CCD is made of a high-sensitivity semiconductor material, which can convert light into electric charge. The charge coupling device is composed of many light-sensitive units, usually in units of millions of pixels. When the surface of the photosensitive element is exposed to light, each light-sensitive unit will reflect the electric charge on the component, and the signals generated by all light-sensitive units together constitute a complete picture.

[0143] The optical lens mainly uses the refraction principle of a lens to form an image, that is, light rays of a scene pass through the optical lens to form a clear image on a focal plane, and the image of the scene is recorded by a photosensitive element located on the focal plane.

[0144] The camera module can be used in an electronic device having a photographing function. For example, the camera module can be used as an endoscope with a photographing function, and the optical lens can be used as an objective lens of the endoscope. Of course, the electronic device can be other electronic devices with a photographing function, and is not limited herein.

[0145] As shown in Figure 1 The optical lens provided by the embodiment of the present application includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged from an object side to an image side; the first lens has a negative focal power, the second lens has a negative focal power, the third lens has a positive focal power, and the fourth lens has a positive focal power; the third lens can move along the optical axis of the optical lens to focus the optical lens between a far focus and a near focus.

[0146] By reasonably distributing the focal power of the optical lens, the focal power of the first lens and the second lens are both negative. When the light passes through each lens group of the optical lens, the light first diverges twice and then converges twice, so that the transition of the light is relatively smooth, which not only reduces aberration, improves the field of view and resolution, and thus improves the imaging quality, but also helps to reduce the aperture of the optical lens.

[0147] As shown in Figure 1 In some embodiments, the optical lens further includes a filter L7.

[0148] In the above manner, the optical lens can have the function of cutting in and out of the light path of a certain filter in the light path, that is, the function of blocking and not blocking the light of the filter, so as to diversify the function of the optical lens, achieve specific optical requirements, and reduce the number of parts and simplify the assembly process of the optical lens. For example, the medical endoscope cold light source light path changes the bandwidth of a certain monochromatic light in the light path without replacing the light-emitting component, thereby achieving the selection requirement of different wavelength light source illumination modes.

[0149] The filter is an infrared cutoff filter. In this way, the interference of infrared rays in the imaging process of the optical lens can be reduced, thereby further improving the imaging quality of the optical lens.

[0150] The infrared cut-off filter is a kind of filter applied to filter infrared wave band. For example, it is installed on the equipment of incandescent lamp (such as slide projector and projector) to block unnecessary heat from burning the lens, and it is installed on the camera of solid-state electronic device (CCD image sensor or CMOS image sensor) to prevent infrared from passing through the lens of the camera to cause picture distortion.

[0151] In some embodiments, the filter is provided with a laser cut-off film (not shown in the figure).

[0152] By providing the filter with a laser cut-off film, the optical lens can be applicable to laser treatment.

[0153] The laser cut-off film can be a YAG laser cut-off film, an LD laser cut-off film or other functional film. The laser cut-off film can be provided on one side of the filter or on both sides of the filter, which is not specifically limited herein.

[0154] As shown in Figure 1 , in some embodiments, the photosensitive element is further provided with a protective sheet L8. In this way, not only the photosensitive element can be protected, but also the photosensitive element can be used as a carrier to facilitate installation.

[0155] As shown in Figure 1 and Figure 6 , the structure light path diagrams of the optical lens in Embodiment One of the present application at the telephoto position and the close-up position are shown. The optical lens includes a first lens L1, a second lens L2, a third lens L3, a diaphragm STO, a fourth lens L4, a fifth lens L5 and a sixth lens L6 arranged from the object side to the image side (arranged in order from left to right as shown in Figure 1 ), and the fifth lens L5 and the sixth lens L6 form a cemented lens. Specifically, the optical power of each lens is shown in Table 1b.

[0156] The fourth lens L4 can move along the optical axis of the optical lens to make the optical lens image between the telephoto position and the close-up position.

[0157] As an optional embodiment of the present application, on the basis of Embodiment One of the present application, the parameter values of each lens of the optical lens can refer to Tables 1a to 1d.

[0158] Table 1a

[0159] Surface No. Surface Type R Value Thickness (mm) Refractive Index Abbe Number OBJ Standard Infinity 15.0(4.00) S1 Standard Infinity 0.405 1.88 42.0 S2 Standard 1.25 0.935 S3 Standard -1.33 0.754 1.50 85.6 S4 Standard -3.16 0.207(0.384) S5 Standard 1.42 0.797 1.76 40.1 S6 Standard 2.05 0.537(0.360) STO Standard Infinity 0.266 S8 Standard 2.04 0.801 1.59 58.3 S9 Standard -1.88 0.395 S10 Standard -17.67 0.757 1.64 60.2 S11 Standard -0.94 0.575 1.85 23.8 S12 Standard -2.99 0.621 S13 Standard Infinity 0.650 1.52 64.2 S14 Standard Infinity 0.350 1.52 64.2 IMAGE Standard Infinity /

[0160] It should be noted that in Table 1a, "face number" is the sequence number of each surface arranged from the object side to the image side, "Standard" in the surface type represents a standard spherical surface, the radius R value is the radius of curvature of the object side surface or the image side surface of the lens corresponding to the surface number, that is, the radius of curvature of the object side surface or the image side surface of the lens corresponding to each face number at the optical axis, "infinite" in the "radius of curvature" parameter series of the lens means that the object side surface or the image side surface of the lens is a plane; the value in the "thickness / interval" parameter series of each lens is the thickness of the lens on the optical axis, or the distance between the image side surface of the lens and the object side surface of the next lens on the optical axis; the value in the "thickness" parameter series of the diaphragm STO is the distance between the center of the diaphragm STO and the object side surface of the next lens on the optical axis.

[0161] "OBJ" refers to the object plane, the two values outside and inside the brackets in the "thickness" parameter series of "OBJ" refer to two different object distances of the optical lens. The value of "S4" in the "thickness" parameter series represents the distance between the image side surface of the second lens L2 and the image side surface of the third lens L3. The value of "S6" in the "thickness" parameter series represents the distance between the image side surface of the third lens L3 and the diaphragm STO.

[0162] Between the second lens L2 and the third lens L3, and between the third lens L3 and the diaphragm STO are different under different object distance focusing. For example, in combination with Lens , Power and Table 1a, when the object distance is 15mm, the distance between the image side surface of the second lens L2 and the image side surface of the third lens L3 is 0.207mm, and the distance between the image side surface of the third lens L3 and the diaphragm STO is 0.537mm. When the object distance is 4mm, the distance between the image side surface of the second lens L2 and the image side surface of the third lens L3 is 0.384mm, and the distance between the image side surface of the third lens L3 and the diaphragm STO is 0.360mm.

[0163] In the embodiments of the present application, the total optical length L of the optical lens is 8.10mm when the optical lens is focused and imaged in the 2mm-100mm depth of field range; the image height is 0.8mm; and the field of view angle is 135°. The focal length f of the optical lens in the present embodiment is 0.86mm at the far focus, and the focal length f is 0.84mm at the near focus.

[0164] It should be noted that the depth of field range of the optical lens in the embodiment is 5mm-100mm at the far focus and 2mm-6mm at the near focus. In addition, regarding the field of view, the field of view of the optical lens in the embodiment is the same at the far focus and the near focus, of course, the field of view of the optical lens at the far focus and the near focus can also be different, generally, the field of view at the near focus can be slightly smaller than the field of view at the far focus, and the specific selection is determined in combination with other optical parameters of the optical lens, which is not limited here.

[0165] The positive and negative cases of the optical power of each lens in the optical lens in the embodiment are shown in Table 1b.

[0166] Table 1b

[0167] Lens L1 L2 L3 L4 L5 L6 Rugate - - + + + -

[0168] It should be noted that "+" and "-" in Table 1b represent the positive and negative cases of the optical power of each lens in the optical lens in Embodiment One. Among them, "+" represents that the lens has positive optical power; "-" represents that the lens has negative optical power.

[0169] The concave-convex cases of the object side or image side of each lens in the optical lens in Embodiment One at the optical axis are shown in Table 1c.

[0170] Table 1c

[0171] Figure 1 L1 L2 L3 L4 L5 L6 Figure 6 ∞+ -- ++ +- -- --

[0172] It should be noted that "∞+", "--", "++", and "+-" in Table 1d represent the concave-convex cases of the object side or image side of each lens at the optical axis. Among them, "∞+" represents that the object side of the lens is a plane at the optical axis, and the image side is convex to the object side at the optical axis; "--" represents that the object side and the image side of the lens are both concave to the object side at the optical axis; "++" represents that the object side and the image side of the lens are both convex to the object side at the optical axis; "+-" represents that the object side of the lens is convex to the object side at the optical axis, and the image side is convex to the object side at the optical axis, that is, a double-convex crescent structure. Of course, the concave-convex cases include "-+", "+∞", "-∞", "∞-", and the like, in addition to those shown in the table. Among them, "-+" represents that the object side of the lens is concave to the object side at the optical axis, and the image side is convex to the object side at the optical axis, that is, a double-concave structure; "+∞" represents that the object side of the lens is convex to the object side at the optical axis, and the image side is a plane at the optical axis; "-∞" represents that the object side of the lens is concave to the object side at the optical axis, and the image side is a plane at the optical axis; "∞-" represents that the object side of the lens is a plane at the optical axis, and the image side is concave to the object side at the optical axis.

[0173] In combination Figure 2 to Figure 5 and Figure 6 to Figure 10The schematic diagram and optical path diagram of the optical lens in Embodiment 1, as well as the main parameters of the optical lens in Embodiment 1 given in Tables 1a to 1c, were obtained through simulation. Figure 2 to Figure 5 , Figure 7 to Figure 10 The simulation diagram is shown below. Among them, Figure 2 The diagrams shown are the magnification chromatic aberration diagram, spherical aberration diagram, astigmatism diagram, and distortion diagram of the optical lens at the telephoto point in Embodiment 1. Figure 7 The diagrams shown are the magnification chromatic aberration diagram, spherical aberration diagram, astigmatism diagram, and distortion diagram of the optical lens at near-focal distance in Embodiment 1.

[0174] in, Figure 3 and Figure 8 The horizontal axis of the magnification chromatic aberration diagram shown represents the vertical position of light of different wavelengths on the image plane of the photosensitive element, and the vertical axis represents the field of view.

[0175] Figure 4 and Figure 9 The horizontal axis of the spherical aberration diagram shown represents the axial position of light of different wavelengths on the image plane of the photosensitive element, in mm; the vertical axis represents the normalized entrance pupil coordinates (note: no unit).

[0176] Figure 5 and Figure 10 The horizontal axis of the astigmatism diagram shown represents the vertical position of light of different wavelengths on the image plane of the photosensitive element, in mm; the vertical axis represents the field of view.

[0177] Figure 2 and Figure 7 The horizontal axis of the distortion graph shown is the distortion value, and the vertical axis is the field of view angle.

[0178] The above descriptions of the magnification chromatic aberration diagram, spherical aberration diagram, astigmatism diagram, and distortion diagram are the same as those in other embodiments, and will not be repeated below.

[0179] from Figure 3 and Figure 8 As can be seen, with the increase of the field of view, the vertical chromatic aberration of the optical lens gradually increases, but the transverse chromatic aberration can be controlled within the allowable offset of the diffraction limit, resulting in smaller chromatic aberration and improved image quality. From Figure 4 and Figure 9 As can be seen, the axial values ​​for different wavelengths are controlled within ±0.05mm, and the chromatic aberration is good throughout the entire entrance pupil range. Therefore, the on-axis chromatic aberration of this optical lens is good. From Figure 5 and Figure 10 As can be seen, the astigmatism value of the optical lens is controlled between -0.01 and 0.05. With the increase of the field of view, the astigmatism of the system gradually increases, but the astigmatism value can be controlled within ±0.05mm, indicating good image quality of the optical lens. Figure 11 andFigure 16 As can be seen, the distortion of the optical lens gradually increases with the increase of the field of view, but the distortion value can be controlled within 80%, reducing the impact of image distortion on image quality. This indicates that the optical lens has good imaging quality.

[0180] Surface No. and Surface Type The diagram shows the structure of the optical lens in Embodiment 2 at the telephoto and near-focal points. The main differences between the optical lens in Embodiment 2 and the optical lens in Embodiment 1 lie in the parameters of each lens, the relationships they satisfy, the optical power, and the concavity / convexity at the optical axis.

[0181] As an optional embodiment of this application, based on Embodiment 2 of this application, the parameter values ​​of each lens of the optical lens can be referred to Tables 2a to 2c.

[0182] Table 2a

[0183] R Value Thickness (mm) Refractive Index Abbe Number OBJ Standard Infinity Standard Infinity 15.0(4.00) S1 Standard Standard 0.450 1.87 41.8 S2 Standard 1.14 0.747 S3 Standard -1.25 0.750 1.49 83.5 S4 Standard -2.83 0.200(0.376) S5 STO 1.50 0.800 1.77 42.1 S6 Standard 2.27 0.536(0.360) Infinity Standard Standard 0.200 S8 Standard 2.19 0.800 1.58 68.3 S9 Standard -2.19 0.398 S10 Standard 18.74 0.765 1.64 65.2 S11 Standard -0.95 0.450 1.83 23.8 S12 Infinity -2.62 0.813 S13 Standard Infinity 0.650 1.52 64.2 S14 IMAGE Standard 0.350 1.52 64.2 Infinity Lens Power /

[0184] In this embodiment, the optical lens has a total optical length L of 7.91 mm, an image height of 0.8 mm, and a field of view of 135° when focusing between 2 mm and 100 mm. The optical lens in this embodiment has a focal length f of 0.85 mm at the telephoto end and a focal length f of 0.83 mm at the near-focal end.

[0185] The positive and negative values ​​of the optical power of each lens in the optical lens in this embodiment are shown in Table 2b.

[0186] Table 2b

[0187] Lens L1 L2 L3 L4 L5 L6 Rugate - - + + + -

[0188] The concavity and convexity of each lens at the optical axis in this embodiment are shown in Table 2c.

[0189] Table 2c

[0190] Figure 11 L1 L2 L3 L4 L5 L6 Figure 16 ∞+ -- ++ +- +- --

[0191] Combination Figure 12 to Figure 20 and Figure 12 The schematic diagram of the optical lens in Embodiment 2 shown, and the main parameters of the optical lens in Embodiment 2 given in Tables 2a to 2c, were obtained through simulation. Figure 17 The simulation diagram shown. From Figure 13 and Figure 18 As can be seen, with the increase of the field of view, the vertical chromatic aberration of the optical lens gradually increases, but the transverse chromatic aberration can be controlled within the allowable offset of the diffraction limit, resulting in smaller chromatic aberration and improved image quality. From Figure 14 and Figure 19It can be seen from the table 1 that the axial values of different wavelengths are controlled within the range of ±0.04mm, and the chromatic aberration is good in the entire entrance pupil range, so the on-axis point chromatic aberration of the optical lens is good. From the table 2, it can be seen that the astigmatism value of the optical lens is controlled between -0.02 and 0.05, and as the field angle increases, the astigmatism of the system gradually increases, but the astigmatism value can be controlled within the range of ±0.05mm, so the image quality of the optical lens is good. Figure 15 and Figure 20 It can be seen from the table 1 that the axial values of different wavelengths are controlled within the range of ±0.04mm, and the chromatic aberration is good in the entire entrance pupil range, so the on-axis point chromatic aberration of the optical lens is good. From the table 2, it can be seen that the astigmatism value of the optical lens is controlled between -0.02 and 0.05, and as the field angle increases, the astigmatism of the system gradually increases, but the astigmatism value can be controlled within the range of ±0.05mm, so the image quality of the optical lens is good. Figure 21 and Figure 26 It can be seen from the table 1 that the axial values of different wavelengths are controlled within the range of ±0.04mm, and the chromatic aberration is good in the entire entrance pupil range, so the on-axis point chromatic aberration of the optical lens is good. From the table 2, it can be seen that the astigmatism value of the optical lens is controlled between -0.02 and 0.05, and as the field angle increases, the astigmatism of the system gradually increases, but the astigmatism value can be controlled within the range of ±0.05mm, so the image quality of the optical lens is good.

[0192] Surface No. and Surface Type The structural diagrams of the optical lens of embodiment three at the far focus and the near focus are shown. The main difference between the structure of the optical lens of embodiment three and the optical lens in embodiment one is that the parameters of each lens, the satisfied relationship, the optical power, and the concave-convex condition at the optical axis.

[0193] As an optional embodiment of the present application, on the basis of embodiment three of the present application, the parameter values of each lens of the optical lens can refer to table 3a to table 3c.

[0194] Table 3a

[0195] R Value Thickness (mm) Refractive Index Abbe Number OBJ Standard Infinity Standard Infinity 15.0(4.00) S1 Standard Standard 0.450 1.86 42.0 S2 Standard 1.04 1.014 S3 Standard -15.31 0.449 1.52 73.0 S4 Standard 5.00 0.381(0.527) S5 STO 1.09 0.560 1.75 45.1 S6 Standard 1.43 0.510(0.365) Infinity Standard Standard 0.395 S8 Standard 1.86 0.685 1.59 68.3 S9 Standard -1.90 0.396 S10 Standard -178.1 0.769 1.64 60.2 S11 Standard -0.90 0.450 1.85 28.8 S12 Infinity -3.33 0.658 S13 Standard Infinity 0.650 1.52 64.2 S14 IMAGE Standard 0.350 1.52 64.2 Infinity Lens Power /

[0196] In the embodiment of the present application, the optical total length L of the optical lens is 7.72mm when the optical lens focuses and images at 2mm-100mm; the image height is 0.8mm; and the field angle is 135°. The focal length f of the optical lens in the embodiment is 0.85mm at the far focus; and the focal length f is 0.83mm at the near focus.

[0197] The positive and negative conditions of the optical power of each lens in the optical lens in the embodiment are shown in table 3b.

[0198] Table 3b

[0199] Lens L1 L2 L3 L4 L5 L6 Rugate - - + + + -

[0200] The concave-convex condition of each lens in the optical lens in the embodiment at the optical axis is shown in table 3c.

[0201] Table 3c

[0202] Figure 21 L1 L2 L3 L4 L5 L6 Figure 26 ∞+ -+ ++ +- -- --

[0203] In combination with Figure 22 to Figure 30 and ​The structure diagram of the optical lens in the fourth embodiment and the main parameters of the optical lens in the third embodiment given in Tables 3a-3c are obtained through simulation ​ The simulation diagram is shown. It can be seen from Figure 22 and Figure 27 that as the field of view angle increases, the vertical chromatic aberration of the optical lens gradually increases, but the vertical axis chromatic aberration can be controlled within the deviation allowed by the diffraction limit, so that the chromatic aberration is small, and the imaging quality is improved. It can be seen from Figure 23 and Figure 28 that the axial values of different wavelengths are controlled within the range of ±0.06 mm, and the chromatic aberration is good within the entire entrance pupil range, so that the on-axis point chromatic aberration of the optical lens is good. It can be seen from Figure 24 and Figure 29 that the astigmatism value of the optical lens is controlled between -0.01 and 0.06, and as the field of view angle increases, the astigmatism of the system gradually increases, but the astigmatism value can be controlled within the range of ±0.06 mm, so that the image quality of the optical lens is good. It can be seen from Figure 25 and Figure 30 that as the field of view angle increases, the distortion of the optical lens gradually increases, but the distortion value can be controlled within the range of 70%, so that the influence of the image distortion on the image quality is reduced. It shows that the imaging quality of the optical lens is good.

[0204] Figure 31 and Figure 36 The structure diagrams of the optical lens of the fourth embodiment at the far focus and the near focus are shown. The main difference between the structure of the optical lens of the fourth embodiment and the optical lens in the first embodiment is that the parameters of each lens, the relationship formula satisfied, the optical power, and the concave-convex condition at the optical axis.

[0205] As an optional embodiment of the present application, on the basis of the fourth embodiment of the present application, the parameter values of each lens of the optical lens can refer to Tables 4a-4c.

[0206] Table 4a

[0207] Surface No. Surface Type R Value Thickness (mm) Refractive Index Abbe Number OBJ Standard Infinity 15.0(4.00) S1 Standard Infinity 0.450 1.88 40.1 S2 Standard 1.16 0.900 S3 Standard -1.85 0.750 1.51 86.6 S4 Standard -5.16 0.200(0.353) S5 Standard 1.13 0.651 1.80 49.5 S6 Standard 1.68 0.636(0.483) STO Standard Infinity 0.526 S8 Standard 5.26 0.800 1.59 68.4 S9 Standard -1.41 0.400 S10 Standard 4.15 0.450 1.85 23.8 S11 Standard 1.18 0.800 1.59 68.4 S12 Standard -10.8 0.500 S13 Standard Infinity 0.650 1.52 64.2 S14 Standard Infinity 0.350 1.52 64.2 IMAGE Standard Infinity /

[0208] In the present embodiment, the optical total length L of the optical lens is 8.06 mm when the optical lens focuses and images at 2 mm-100 mm; the image height is 0.81 mm; and the field of view angle is 135°. The focal length f of the optical lens in the present embodiment is 0.84 mm at the far focus; and the focal length f is 0.82 mm at the near focus.

[0209] The positive and negative conditions of the optical power of each lens in the optical lens in the present embodiment are shown in Table 4b.

[0210] Table 4b

[0211] Lens L1 L2 L3 L4 L5 L6 Power - - + + - +

[0212] The concave-convex condition of each lens in the optical lens in the embodiment at the optical axis is shown in Table 4c.

[0213] Table 4c

[0214] Lens L1 L2 L3 L4 L5 L6 Concave Convex Situation ∞+ -- ++ +- ++ +-

[0215] In combination Figure 31 and Figure 36 The structural schematic diagram of the optical lens in Embodiment Four shown in the figure, and the main parameters of the optical lens in Embodiment Four given in Table 4a to Table 4c are obtained by simulation Figures 32 to 40 The simulation diagram shown. As can be seen from Figure 32 and Figure 37 , as the field of view angle increases, the vertical chromatic aberration of the optical lens gradually increases, but the vertical chromatic aberration can be controlled within the deviation allowed by the diffraction limit, so that the chromatic aberration is small, and the imaging quality is improved. As can be seen from Figure 33 and Figure 38 , the axial values of different wavelengths are controlled within the range of ±0.05mm, and the chromatic aberration is good within the entire entrance pupil range, so that the on-axis point chromatic aberration of the optical lens is good. As can be seen from Figure 34 and Figure 39 , the astigmatism value of the optical lens is controlled between 0.01 and 0.06, and as the field of view angle increases, the astigmatism of the system gradually increases, but the astigmatism value can be controlled within the range of ±0.06mm, so that the image quality of the optical lens is good. As can be seen from Figure 35 and Figure 40 , as the field of view angle increases, the distortion of the optical lens gradually increases, but the distortion value can be controlled within the range of 70%, so as to reduce the influence of image distortion on the image quality. It is shown that the imaging quality of the optical lens is good.

[0216] Figure 41 and Figure 46 The structural diagrams of the optical lens in Embodiment Five at the far focus and the near focus are shown. The main difference between the structure of the optical lens in Embodiment Five and the optical lens in Embodiment One lies in the parameters of each lens, the relationship formula satisfied, the optical power, and the concave-convex condition at the optical axis.

[0217] As an optional embodiment of the present application, on the basis of Embodiment Five of the present application, the parameter values of each lens of the optical lens can refer to Table 5a to Table 5c.

[0218] Table 5a

[0219] Surface No. Surface Type R Value Thickness (mm) Refractive Index Abbe Number OBJ Standard Infinity 15.0(4.00) S1 Standard Infinity 0.400 1.83 42.0 S2 Standard 1.14 0.891 S3 Standard -1.52 0.791 1.48 72.4 S4 Standard .2.77 0.195(0.445) S5 Standard 1.37 0.590 1.74 27.3 S6 Standard 1.85 1.125(0.875) STO Standard Infinity 0.371 S8 Standard 7.35 0.900 1.45 90.3 S9 Standard -1.19 0.441 S10 Standard 6.59 0.683 1.55 68.1 S11 Standard -1.20 0.701 1.75 35.5 S12 Standard -5.36 1.021 S13 Standard Infinity 0.650 1.52 64.2 S14 Standard Infinity 0.350 1.52 64.2 IMAGE Standard Infinity /

[0220] In the embodiment of the present application, the optical total length L of the optical lens is 9.11 mm when the optical lens focuses and images at 2 mm-100 mm; the image height is 0.81 mm; and the field of view angle is 160°. The focal length f of the optical lens in the embodiment is 0.82 mm at the far focus and is 0.80 mm at the near focus.

[0221] The positive and negative cases of the refractive power of each lens in the optical lens in the embodiment are shown in Table 5b.

[0222] Table 5b

[0223] Lens L1 L2 L3 L4 L5 L6 Power - - + + + -

[0224] The concave-convex cases of each lens at the optical axis in the optical lens in the embodiment are shown in Table 5c.

[0225] Table 5c

[0226] Lens L1 L2 L3 L4 L5 L6 Concave Convex Situation ∞+ -- ++ +- +- --

[0227] In combination Figure 41 and Figure 46 the structure schematic diagram of the optical lens in Embodiment Five shown in the embodiment and the main parameters of the optical lens in Embodiment Five given in Table 5a to Table 5c are obtained by simulation Figures 42 to 50 The simulation diagram shown in the simulation. As can be seen from Figure 42 and Figure 47 , as the field of view angle increases, the vertical chromatic aberration of the optical lens gradually increases, but the vertical chromatic aberration can be controlled within the deviation allowed by the diffraction limit, so that the chromatic aberration is small, and the imaging quality is improved. As can be seen from Figure 43 and Figure 48 , the axial values of different wavelengths are controlled within the range of ±0.06 mm, and the chromatic aberration is good within the entire entrance pupil range, so that the on-axis point chromatic aberration of the optical lens is good. As can be seen from Figure 44 and Figure 49 , the astigmatism value of the optical lens is controlled between -0.01 and 0.06, and as the field of view angle increases, the astigmatism of the system gradually increases, but the astigmatism value can be controlled within the range of ±0.06 mm, so that the image quality of the optical lens is good. As can be seen from Figure 45 and Figure 50 , as the field of view angle increases, the distortion of the optical lens gradually increases, but the distortion value can be controlled within the range of 80%, so as to reduce the influence of image distortion on the image quality. It is shown that the imaging quality of the optical lens is good.

[0228] Figure 51 and Figure 56The structural diagrams of the optical lens of embodiment six at far focus and near focus are shown. The main difference between the structure of the optical lens of embodiment six and the optical lens of embodiment one is the parameters of the lenses, the satisfied relational expression, the optical power, and the concave-convex condition at the optical axis.

[0229] As an optional embodiment of the present application, on the basis of embodiment six of the present application, the parameter values of the lenses of the optical lens can refer to table 6a to table 6c.

[0230] Table 6a

[0231] Surface No. Surface Type R Value Thickness (mm) Refractive Index Abbe Number OBJ Standard Infinity 15.0(4.00) S1 Standard Infinity 0.400 1.83 42.0 S2 Standard 1.12 0.944 S3 Standard -1.35 0.801 1.47 70.4 S4 Standard -2.24 0.760(0.972) S5 Standard 1.48 0.800 1.76 52.7 S6 Standard 1.80 1.181(0.969) STO Standard Infinity 0.281 S8 Standard 1.48 0.533 1.62 60.4 S9 Standard -17.17 0.400 S10 Standard 20.31 0.450 1.85 35.3 S11 Standard 0.96 0.715 1.58 71.0 S12 Standard -1.60 1.079 S13 Standard Infinity 0.650 1.52 64.2 S14 Standard Infinity 0.350 1.52 64.2 IMAGE Standard Infinity /

[0232] In the embodiment of the present application, the total optical length L of the optical lens is 9.34 mm when the optical lens focuses and images at 2 mm-100 mm; the image height is 0.81 mm; and the field of view angle is 160°. The focal length f of the optical lens in the embodiment is 0.79 mm at far focus; and the focal length f of the optical lens in the embodiment is 0.77 mm at near focus.

[0233] The positive and negative conditions of the optical power of each lens in the optical lens in the embodiment are shown in table 4b.

[0234] Table 6b

[0235] Lens L1 L2 L3 L4 L5 L6 Power - - + + - +

[0236] The concave-convex condition of each lens at the optical axis in the optical lens in the embodiment is shown in table 6c.

[0237] Table 6c

[0238] Lens L1 L2 L3 L4 L5 L6 Concave Convex Situation ∞+ -- ++ +- ++ +-

[0239] In combination Figure 51 and Figure 56 The structural schematic diagram of the optical lens in embodiment six shown and the main parameters of the optical lens in embodiment six given in table 6a to table 6c are obtained through simulation Figures 52 to 60 The simulation diagram shown. It can be seen from Figure 52 and Figure 57 that as the field of view angle increases, the vertical chromatic aberration of the optical lens gradually increases, but the vertical chromatic aberration can be controlled within the deviation allowed by the diffraction limit, so that the chromatic aberration is small, and the imaging quality is improved. It can be seen from Figure 53 and Figure 58 that the axial values of different wavelengths are controlled within the range of ±0.06 mm, and the chromatic aberration is good within the entire entrance pupil range, so that the on-axis point chromatic aberration of the optical lens is good. It can be seen from Figure 54 and Figure 59It can be seen from the above that the astigmatism value of the optical lens is controlled between -0.01 and 0.06, and as the field of view angle increases, the astigmatism of the system gradually increases, but the astigmatism value can be controlled within the range of ±0.06 mm, and the image quality of the optical lens is better. Figure 55 and Figure 60 It can be seen from the above that as the field of view angle increases, the distortion of the optical lens gradually increases, but the distortion value can be controlled within the range of 80%, thereby reducing the influence of image distortion on image quality. It is shown that the imaging quality of the optical lens is better.

[0240] Figure 61 and Figure 66 The structural diagrams of the optical lens of Example Seven at the far focus and the near focus are shown. The main difference between the structure of the optical lens of Example Seven and the optical lens in Example One is that the parameters of each lens, the satisfied relationship, the optical power, and the concave-convex condition at the optical axis are different.

[0241] As an optional embodiment of the present application, on the basis of Example Seven of the present application, the parameter values of each lens of the optical lens can refer to Table 7a to Table 7c.

[0242] Table 7a

[0243] Surface No. Surface Type R Value Thickness (mm) Refractive Index Abbe Number OBJ Standard Infinity 15.0(4.00) S1 Standard Infinitv 0.450 1.86 40.1 S2 Standard 1.13 0.830 S3 Standard -1.33 0.631 1.45 70.4 S4 Standard -2.62 0.188(0.439) S5 Standard 1.62 0.803 1.74 25.7 S6 Standard 2.00 0.770(0.519) STO Standard Infinitv 0.221 S8 Standard 2.95 0.685 1.48 90.3 S9 Standard -1.10 0.442 S10 Standard 15.18 0.745 1.55 78.3 S11 Standard -1.15 0.449 1.78 29.5 S12 Standard -4.32 0.830 S13 Standard Infinitv 0.650 1.52 64.2 S14 Standard Infinity 0.350 1.52 64.2 IMAGE Standard Infinity /

[0244] In the present application, the total optical length L of the optical lens is 8.04 mm when the optical lens focuses and images at 2 mm-100 mm; and the image height is 0.81 mm. The focal length f of the optical lens in the present embodiment is 0.83 mm at the far focus, and the field of view angle is 156°; the focal length f is 0.81 mm at the near focus, and the field of view angle is 148°.

[0245] The positive and negative conditions of the optical power of each lens in the optical lens in the present embodiment are shown in Table 7b.

[0246] Table 7b

[0247] lens L1 L2 L3 L4 L5 L6 power - - + + + -

[0248] The concave-convex condition of each lens at the optical axis in the optical lens in the present embodiment is shown in Table 7c.

[0249] Table 7c

[0250] lens L1 L2 L3 L4 L5 L6 concave-convex case ∞+ -- ++ +- +- --

[0251] In combination with Fig. 61 and Fig. 66 the structural schematic diagram of the optical lens in Example Seven shown, and the main parameters of the optical lens in Example Seven given in Table 7a to Table 7c, the simulation diagram shown in Figs. 62 to 70 is obtained through simulation simulation. From Fig. 62 andFig. 67 As can be seen from the tables and the curves, with the increase of the field angle, the vertical chromatic aberration of the optical lens gradually increases, but the vertical chromatic aberration can be controlled within the deviation allowed by the diffraction limit, so that the chromatic aberration is small, and the imaging quality is improved. Fig. 63 and Fig. 68 As can be seen from the tables and the curves, the axial values of different wavelengths are controlled within the range of ±0.06 mm, and the chromatic aberration is good within the entire entrance pupil range, so that the on-axis point chromatic aberration of the optical lens is good. Fig. 64 and Fig. 69 As can be seen from the tables and the curves, the astigmatism value of the optical lens is controlled between-0.02 and 0.06, and with the increase of the field angle, the astigmatism of the system gradually increases, but the astigmatism value can be controlled within the range of ±0.06 mm, so that the image quality of the optical lens is good. Fig. 65 and Fig. 70 As can be seen from the tables and the curves, with the increase of the field angle, the distortion of the optical lens gradually increases, but the distortion value can be controlled within the range of 80%, so as to reduce the influence of image distortion on the image quality. It is shown that the imaging quality of the optical lens is good.

[0252] Table 10 shows the optical parameters of the optical lens in the ten embodiments of the present application including the above seven embodiments.

[0253] Table 10

[0254] optical parameters Example One Example Two Example Three Example Four Example Five f4 / f2 -0.32 -0.37 -0.22 -0.32 -0.27 f4 / fm 0.08 0.29 0.05 0.07 0.23 fm / f 25.92 7.77 43.05 35.03 12.36 f2 / f1 0.25 0.24 0.24 0.21 0.15 (R1-R2) / (R1+R2) -0.40 -0.39 1.97 -0.47 -0.29 f3 / f 4.62 4.66 4.17 3.73 6.30 optical parameters Example Six Example Seven Example Eight Example Nine Example Ten f4 / f2 -0.22 -0.28 -0.14 -0.49 -0.24 f4 / fm 0.21 0.13 0.06 0.06 0.50 fm / f 12.83 17.62 27.43 36.36 6.17 f2 / f1 0.12 0.19 0.11 0.35 0.11 (R1-R2) / (R1+R2) -0.25 -0.33 -0.21 -0.84 -0.27 f3 / f 6.13 5.98 3.44 3.90 7.24

[0255] Note: The notes of the relationship of the optical lens in each of the following embodiments are as follows:

[0256] f is the focal length of the optical lens, which is equal to the EFL value of the optical lens.

[0257] f1 is the focal length of the first lens L1 in the optical lens;

[0258] f2 is the focal length of the second lens L2 in the optical lens;

[0259] f3 is the focal length of the third lens L3 in the optical lens;

[0260] f4 is the focal length of the fourth lens L4 in the optical lens;

[0261] fm is the focal length of the cemented lens composed of the fifth lens L5 and the sixth lens L6 in the optical lens, that is, equal to the combined focal length of the fifth lens L5 and the sixth lens L6;

[0262] R1 is the curvature of the object side surface of the second lens in the optical lens;

[0263] R2 is the curvature of the image side surface of the second lens in the optical lens.

[0264] It should be noted that the optical parameters of the optical lens in the above embodiment one to embodiment seven correspond to the above seven embodiments. Since the structures of the optical lens in embodiment eight, embodiment nine and embodiment ten are the same as the above seven embodiments, only the parameters are different, therefore, the optical parameters of the relationship formula corresponding to the optical lens in embodiment eight, embodiment nine and embodiment ten are listed in table 10.

[0265] From the optical parameters of the ten embodiments given in the above table 10, it can be seen that the optical lens of the present application satisfies the relationship formula: -0.5 < f4 / f2 < -0.1.

[0266] If the ratio f4 / f2 is too small, the length of the optical lens is too long, which is not conducive to use in products with limited installation space; if the ratio f4 / f2 is too large, the imaging quality of the optical lens in the depth of field range is poor, and the correction of spherical aberration, coma and chromatic aberration is difficult, and a high-resolution image cannot be obtained.

[0267] By reasonably selecting the above parameters, when the ratio f4 / f2 satisfies the above relationship formula, the appropriate ratio of the focal length of the fourth lens L4 and the focal length of the second lens L2 is conducive to the correction of aberration and the improvement of the imaging quality in the depth of field range, and the total optical length of the optical lens is relatively short, which is conducive to reducing the length of the entire optical lens. When the optical lens is used as an endoscope objective lens installed in the hard part of the endoscope, it is conducive to reducing the length of the hard part of the endoscope.

[0268] From the optical parameters of the ten embodiments given in the above table 10, it can be seen that the optical lens of the present application satisfies the relationship formula: 0 < f4 / fm < 0.5.

[0269] If the ratio f4 / fm is too small, the aberration generated by the fourth lens L4 cannot be completely corrected, which has a greater impact on the imaging quality of the entire optical lens; if the ratio f4 / fm is too large, not only the total length of the optical lens is too long, but also the aberration generated by the last two lenses cannot be completely corrected.

[0270] By reasonably selecting the above parameters, when the ratio f4 / fm satisfies the above relationship formula, it is not only conducive to the correction of aberration of the optical lens and the improvement of the imaging quality, but also shortens the total length of the optical lens.

[0271] From the optical parameters of the ten embodiments given in the above table 10, it can be seen that the optical lens of the present application satisfies the relationship formula: 2 < fm / f < 50.

[0272] By reasonably selecting the above parameters, when the ratio fm / f satisfies the above relationship, better light collection can be achieved after the light passes through the optical lens, the overall brightness of the picture is improved, and the correction of the axial chromatic aberration and the sagittal chromatic aberration is beneficial, the aberration generated by other lenses is balanced, the imaging quality is improved, and the total length of the optical lens is shortened. In addition, when the fifth lens L5 and the sixth lens L6 are cemented to form a cemented lens, not only the tolerance sensitivity is reduced, but also the imaging quality can be further improved, and the length of the optical lens is further reduced, and the assembly of the optical lens is more convenient.

[0273] As can be seen from the optical parameters of the ten embodiments given in Table 10, the optical lens of the present application satisfies the relationship: 0.1 < f2 / f1 < 0.4.

[0274] If the ratio f2 / f1 is too small, the first lens L1 of the optical lens generates a larger aberration, the design difficulty of the entire optical lens is increased, and the tolerance sensitivity is poor. If the ratio f2 / f1 is too large, the aperture of the first lens L1 of the optical lens is large, and it is difficult to achieve miniaturization. Miniaturization refers to the aperture of the optical lens being as small as possible. Especially when the optical lens is used as an endoscope objective lens, it is an important indicator of optical lens design.

[0275] By reasonably selecting the above parameters, when the ratio f2 / f1 satisfies the above relationship, the difference between the negative focal lengths of the first lens L1 and the second lens L2 is small, and the deflection angle of the light is small when the light passes through. Not only can the aberration and the spherical aberration of the optical lens be well corrected, thereby further improving the imaging quality of the optical lens, but also it is beneficial to the miniaturization of the optical lens.

[0276] As can be seen from the optical parameters of the ten embodiments given in Table 10, the optical lens of the present application satisfies the relationship: 2 < f3 / f < 8.

[0277] If the ratio f3 / f is too small, the spherical aberration of the first lens L1 and the second lens L2 cannot be well corrected, resulting in poor imaging quality. If the ratio f3 / f is too large, the imaging quality of the optical lens is improved, but the length of the optical lens is too long, which is not conducive to miniaturization design.

[0278] By reasonably distributing the focal lengths of the lenses of the optical lens, when the ratio f3 / f satisfies the above relationship, the aberration of the third lens L3 and the remaining lenses cancels each other out, improving the imaging quality. At the same time, it is also beneficial to shorten the length of the optical lens, and thus realize the miniaturization design of the optical lens.

[0279] As can be seen from the optical parameters of the ten embodiments given in Table 10, the radii of curvature R1 of the object side of the second lens group and the radii of curvature R2 of the image side of the optical lens satisfy the relationship: -1 < (R1-R2) / (R1+R2) < 3.

[0280] If the ratio (R1-R2) / (R1+R2) is too small, the correction of astigmatism and coma of the optical lens is excessive; if the ratio (R1-R2) / (R1+R2) is too large, the processability of the second lens L2 is reduced, and the correction effect of the aberration is also reduced, which cannot balance the aberration generated by the first lens L1 and the third lens L3 in the optical lens, and has a greater impact on the optical imaging quality.

[0281] By reasonably selecting the above parameters, when the ratio (R1-R2) / (R1+R2) satisfies the above relationship, on the one hand, the deflection angle of the edge light of the second lens L2 can be effectively controlled, that is, the light at the circumference passing through the second lens L2 will not deflect too much towards the direction close to the optical axis or the edge direction, so that the light at the circumference passing through the second lens L2 is relatively flat, the diameter of the light beam is effectively controlled, the size of the second lens L2 in the direction perpendicular to the optical axis is effectively controlled, and the size of the optical lens in the direction perpendicular to the optical axis is shortened; on the other hand, the thickness of the second lens L2 will not be too thin, which is easy to process.

[0282] In summary, when the optical lens in the application is focused in the 2mm-100mm depth of field range, the total optical length of the optical lens is controlled in the range of 7.72mm-9.11mm, which indicates that the size of the optical lens is relatively small. The image height is greater than 0.8mm, which indicates that the resolution of the optical lens is relatively high; the field of view angle can reach 135°-160°; at the same time, as can be seen from the simulation diagrams of each embodiment, the optical lens in the application can achieve the purpose of considering large field of view angle, high image quality and miniaturization in the 2mm-100mm depth of field range. When the optical lens is used as an endoscope objective lens, the endoscope comprising the optical lens of the application can be used for colonoscopy and gastroscopy detection.

[0283] The embodiment of the application also provides an endoscope comprising the camera module in any of the above embodiments. The endoscope has the same beneficial effects as the camera module in the above embodiments, and will not be described here again.

[0284] The embodiment of the application also provides an endoscope system comprising a light source host, an image processing device and an endoscope.

[0285] The above image processing device is in communication connection with the light source host, and the light source host is in detachable connection with the endoscope. For example, the light source host and the endoscope can be plug-in connection.

[0286] When the light source host and the image processing device are a two-in-one all-in-one device, there is no concept of corresponding connection.

[0287] The endoscope system further comprises a display connected in communication with the image processing device. The display can be provided as a separate device or integrated in the image processing device, which is not specifically limited here.

[0288] The endoscope system has the same beneficial effects as the endoscope in the above embodiments, which will not be repeated here.

[0289] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An optical lens characterized in that, consisting of a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged from an object side to an image side; the first lens has negative refractive power, the second lens has negative refractive power, the third lens has positive refractive power, and the fourth lens has positive refractive power; an object side surface of the first lens is planar at the optical axis and convex toward the object side at the optical axis, an object side surface of the second lens is convex toward the image side at the optical axis, an object side surface of the third lens is convex toward the object side at the optical axis and an image side surface of the third lens is convex toward the object side at the optical axis, an object side surface of the fourth lens is convex toward the object side at the optical axis and an image side surface of the fourth lens is convex toward the image side at the optical axis, and an image side surface of the sixth lens is convex toward the image side at the optical axis; the third lens is movable along the optical axis of the optical lens to focus the optical lens between a far focus and a near focus; a focal length f4 of the fourth lens of the optical lens and a focal length f2 of the second lens satisfy a relationship of -0.5 < f4 / f2 < -0.1; a focal length f1 of the first lens of the optical lens and the focal length f2 of the second lens satisfy a relationship of 0.1 < f2 / f1 < 0.

4.

2. The optical lens of claim 1, wherein, the fifth lens and the sixth lens form a cemented lens.

3. The optical lens of claim 2, wherein, the cemented lens has positive refractive power.

4. The optical lens according to claim 3, wherein: a combined focal length fm of the cemented lens and the focal length f4 of the fourth lens satisfy a relationship of 0 < f4 / fm < 0.5; and / or, the combined focal length fm of the cemented lens and an effective focal length f of the optical lens at the far focus satisfy a relationship of 2 < fm / f < 50.

5. The optical lens according to any one of claims 1 to 4, characterized in that, a radius of curvature R1 of an object side surface of the second lens and a radius of curvature R2 of an image side surface of the second lens satisfy a relationship of -1 < (R1-R2) / (R1+R2) < 3.

6. The optical lens according to any one of claims 1 to 4, characterized in that, a focal length f3 of the third lens and the effective focal length f of the optical lens at the far focus satisfy a relationship of 2 < f3 / f < 8.

7. The optical lens according to any one of claims 1 to 4, characterized in that, the optical lens further comprises a stop, the stop being located between the third lens and the fourth lens.

8. A camera module, comprising: comprising: the optical lens according to any one of claims 1-7; and a photosensitive element disposed on an image side of the optical lens.

9. The camera module of claim 8, wherein, a filter is further disposed between the photosensitive element and the optical lens.

10. An endoscope characterized by comprising: comprising: the camera module according to any one of claims 8-9.

11. An endoscope system characterized by comprising: comprising: a light source host, an image processing device, and the endoscope according to claim 10.

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