Optical system and endoscope

Abstract

An optical system and an endoscope, the optical system has ten lenses with optical power, sequentially includes a fixed lens group and a moving lens group from the object side to the image side along the optical axis direction, the fixed lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens arranged in order from the object side to the image side along the optical axis direction, the moving lens group includes a ninth lens and a tenth lens arranged in order from the object side to the image side along the optical axis direction, the ninth lens and the tenth lens are combined as a moving cemented lens, and the moving lens group can move along the optical axis; the optical system satisfies the condition formula: 120° ≤ FOV ≤ 175°, wherein FOV is the maximum field of view angle in the diagonal direction of the optical system. The optical system in the utility model can meet the requirements of large field of view angle and miniaturization simultaneously.

Description

Technical Field

[0001] This utility model relates to the field of optical system technology, specifically to an optical system and an endoscope. Background Technology

[0002] In the medical field, endoscopes are being used more and more widely. Endoscopes are mainly used for minimally invasive surgery or for examination or treatment through the body's natural cavities. By inserting an endoscope into a body cavity, images of the interior of the cavity can be obtained, which can help doctors effectively diagnose lesions.

[0003] Currently used endoscope lenses are large in size and have insufficient field of view. Utility Model Content

[0004] The purpose of this invention is to provide an optical system and endoscope that solves the problems of large overall size and insufficient field of view of the optical system.

[0005] To achieve the objectives of this utility model, the following technical solution is provided:

[0006] In a first aspect, this utility model provides an optical system having ten lenses with optical power, comprising a fixed lens group and a movable lens group sequentially arranged from the object side to the image side along the optical axis. The fixed lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from the object side to the image side along the optical axis. The movable lens group includes a ninth lens and a tenth lens arranged sequentially from the object side to the image side along the optical axis. The ninth lens and the tenth lens are combined to form a movable cemented lens. The movable lens group is movable along the optical axis.

[0007] The optical system satisfies the condition: 120°≤FOV≤175°;

[0008] Wherein, FOV is the maximum field of view in the diagonal direction of the optical system.

[0009] In one embodiment, the first lens has negative optical power; the second lens and the third lens are combined to form a first cemented lens, which has positive optical power; the fourth lens has negative optical power; the fifth lens and the sixth lens are combined to form a second cemented lens; the seventh lens and the eighth lens are combined to form a third cemented lens, and the combined optical power of the second cemented lens and the third cemented lens is positive.

[0010] In one embodiment, the optical system further includes a filter;

[0011] The filter is disposed between the second cemented lens and the third cemented lens, or the filter is disposed on the side of the second cemented lens facing away from the third cemented lens, or the filter is disposed on the side of the third cemented lens facing away from the second cemented lens.

[0012] In one embodiment, the object-side surface of the ninth lens is convex near the optical axis, and the image-side surface is concave near the optical axis; the object-side surface of the tenth lens is concave near the optical axis.

[0013] In one embodiment, the optical system satisfies the condition: 3mm≤F≤100mm;

[0014] Wherein, F represents the focal length of the optical system.

[0015] In one embodiment, the optical system satisfies the condition: TTL≤11mm;

[0016] Wherein, TTL is the distance on the optical axis from the side of the first lens to the imaging surface of the optical system.

[0017] In one embodiment, the optical system satisfies the condition: 4mm≤|R9+R10+R12|≤50mm;

[0018] Wherein, R9 is the radius of curvature of the object side of the fifth lens at the optical axis, R10 is the radius of curvature of the image side of the fifth lens at the optical axis, and R12 is the radius of curvature of the image side of the sixth lens at the optical axis.

[0019] In one embodiment, the optical system satisfies the condition: 0.8mm≤|R13+R14+R16|≤25mm;

[0020] Wherein, R13 is the radius of curvature of the object side of the seventh lens at the optical axis, R14 is the radius of curvature of the image side of the seventh lens at the optical axis, and R16 is the radius of curvature of the image side of the eighth lens at the optical axis.

[0021] In one embodiment, the optical system satisfies the condition: 1.5mm ≤ g1 ≤ 3mm;

[0022] Wherein, g1 is the distance on the optical axis from the object side of the ninth lens to the image side of the tenth lens.

[0023] Secondly, the present invention also provides an endoscope, including an electronic photosensitive element and an optical system as described in any one of the various embodiments of the first aspect, wherein the electronic photosensitive element is disposed on the image side of the optical system.

[0024] By setting up a reasonable configuration of fixed lens group and movable lens group, the movable lens group can move along the optical axis and adjust the overall focal length of the optical system. While providing a large field of view, it reduces the focusing displacement value of the optical system, so that the optical system can meet the requirements of both a large field of view and miniaturization. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of an optical system according to one embodiment. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that when a component is said to be "fixed" to another component, it can be directly on the other component or it can be in a middle component. When a component is said to be "connected" to another component, it can be directly connected to the other component or it may be in a middle component.

[0029] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0030] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0031] This utility model provides an endoscope, including an electronic photosensitive element and an optical system as described in this utility model embodiment, wherein the electronic photosensitive element is disposed on the image side of the optical system.

[0032] In the medical field, endoscopes are increasingly widely used. The working principle of an endoscope is primarily based on optical principles and modern electronic technology. It uses optical lenses such as objective lenses and eyepieces to focus images of internal structures and lesions, which are then transmitted to external devices via image bundles or fiber optic bundles. In electronic endoscopes, image sensors convert light signals into electrical signals, which are then digitally processed and enhanced by an image processor before being displayed on a monitor or computer screen, providing doctors with intuitive and accurate diagnostic and treatment information. Some existing optical systems used in endoscopes have focusing capabilities, enabling the endoscope to obtain clear images over a wide range, from near to far, facilitating the search and observation of lesions by doctors.

[0033] Optionally, the endoscope includes a lens with a barrel. A first to tenth lens of the optical system is mounted in the barrel. An electronic photosensitive element is disposed on the image side of the optical system to convert light rays passing through the first to tenth lenses and incident on the electronic photosensitive element into electrical signals for an image. The electronic photosensitive element can be a complementary metal-oxide-semiconductor (CMOS) or a charge-coupled device (CCD). This application, by applying this optical system to an endoscope and rationally configuring the surface shape and optical power of each lens in the optical system, enables the endoscope lens to simultaneously meet the requirements of wide-range zoom and miniaturization.

[0034] The optical system in the embodiments of this utility model will be described in detail below.

[0035] Please refer to Figure 1 This utility model provides an optical system with ten lenses having optical power, which includes a fixed lens group and a movable lens group in sequence from the object side to the image side along the optical axis.

[0036] The fixed lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, arranged sequentially from the object side to the image side along the optical axis. The movable lens group includes a ninth lens and a tenth lens, arranged sequentially from the object side to the image side along the optical axis. The ninth and tenth lenses are combined to form a movable cemented lens. The movable lens group can move along the optical axis. By changing the distance between the movable lens group and the fixed lens group, different working distances can be provided for the optical system, increasing the depth of field. Furthermore, the overall size of the movable lens group is relatively small, requiring minimal space and not increasing the overall length of the optical system.

[0037] In one embodiment, the optical system satisfies the condition: 120° ≤ FOV ≤ 175°, where FOV is the maximum field of view angle along the diagonal direction of the optical system. When the optical system satisfies the above condition, by reasonably configuring the field of view angle of the optical system, a larger field of view range can be obtained, thus improving the observation range. When the FOV is too small, the range that the user can observe is limited, which is insufficient to meet the user's field of view requirements; when the FOV is too large, the image edges may be stretched or compressed, and the image resolution may also decrease. Optionally, the FOV value can be 120°, 125°, 125°, 130°, 135°, 140°, 145°, 150°, 155°, 160°, 165°, 170°, or 175°.

[0038] The optical system in this embodiment of the invention, by reasonably configuring the fixed lens group and the movable lens group, allows the movable lens group to move along the optical axis and adjust the overall focal length of the optical system, thereby reducing the focusing displacement value of the optical system and enabling the optical system to simultaneously meet the requirements of a large field of view and miniaturization.

[0039] In one embodiment, the first lens has negative optical power; the second and third lenses are combined to form a first cemented lens, which has positive optical power; the fourth lens has negative optical power; the fifth and sixth lenses are combined to form a second cemented lens; the seventh and eighth lenses are combined to form a third cemented lens; and the combined optical power of the second and third cemented lenses is positive.

[0040] In one specific embodiment, reference is made to... Figure 1 The first lens has positive optical power, and its image-side surface is convex near the optical axis. This lens is responsible for deflecting large-angle incident light. The second lens has negative optical power, and its object-side surface is concave near the optical axis, while its image-side surface is convex near the optical axis. The third lens has positive optical power, and its object-side surface is convex near the optical axis, while its image-side surface is concave near the optical axis. The first cemented lens, formed by combining the second and third lenses, has positive optical power and is responsible for confining and collimating diverging light rays, as well as partially adjusting chromatic aberration. The fourth lens has negative optical power, and both its object-side and image-side surfaces are concave near the optical axis. Through the combination of these four lenses, a maximum field of view is achieved. The fifth lens has negative optical power, and both its object-side and image-side surfaces are convex near the optical axis. The sixth lens has positive optical power, and both its object-side and image-side surfaces are convex near the optical axis. The seventh lens has positive optical power, and both its object-side and image-side surfaces are concave near the optical axis. The eighth lens has positive optical power, and both its object-side and image-side surfaces are concave near the optical axis. The second and third cemented lenses are designed to improve image quality while reducing transverse aberration.

[0041] By rationally configuring the optical power of each lens in the fixed lens group, it is beneficial to control the aberrations generated by the fixed lens group and balance them with the aberration components contributed by the moving lens group, thereby improving the imaging quality of the optical system. In addition, it is also beneficial to rationally constrain the surface shape of each lens in the fixed lens group and reduce the difficulty of molding and processing.

[0042] In one embodiment, the optical system further includes a filter. The filter is disposed between the second cemented lens and the third cemented lens, or the filter is disposed on the side of the second cemented lens facing away from the third cemented lens, or the filter is disposed on the side of the third cemented lens facing away from the second cemented lens.

[0043] In one specific implementation, such as Figure 1 The filter is positioned between the second and third cemented lenses, which are approximately symmetrical about the filter. This arrangement improves image quality while reducing transverse aberration.

[0044] Optical filters, as optical elements with specific spectral characteristics, are used to selectively transmit or reflect light of specific wavelengths. They can adjust the wavelength and intensity of light as needed to improve image quality or enhance the contrast of specific tissues. For example, when observing blood vessels, using a blue filter can enhance their visibility; when observing the gastrointestinal tract, using a green filter can highlight details on the mucosal surface. The application of filters makes medical endoscopes more accurate and reliable in diagnosing various diseases. Different tissues and lesions have different absorption and reflection characteristics of light; therefore, selecting an appropriate filter can make endoscopic images clearer and more accurate. For example, light with a 440nm filter wavelength is easily absorbed by the fibrous tissue of the mucosal layer, while light with a 540nm filter wavelength mainly acts on the submucosal blood vessels, allowing the user to more accurately observe the extent and characteristics of lesions.

[0045] By setting up filters and determining their position within the optical system, image quality can be improved and the contrast of specific tissues can be enhanced.

[0046] In one embodiment, the object-side surface of the ninth lens is convex near the optical axis, and the image-side surface is concave near the optical axis; the object-side surface of the tenth lens is also concave near the optical axis. The ninth and tenth lenses are combined to form a movable cemented lens, which can move along the optical axis, thereby adjusting the focal length of the optical system and providing different working distances to increase the depth of field.

[0047] Optionally, the ninth lens has positive optical power, and the tenth lens has negative optical power. Using the ninth and tenth lenses in combination allows for adjustment of the beam diameter.

[0048] In one embodiment, the optical system satisfies the condition: 3mm ≤ F ≤ 100mm; where F represents the focal length of the optical system. When the optical system satisfies the above condition, a reasonable configuration of the focal length of the optical system is beneficial for obtaining a wider zoom range in the telephoto direction. Furthermore, by moving the lens group along the optical axis, the focal length of the optical system can be changed, enabling clear imaging over a wide working distance. When F is too large or too small, the focal length of the optical system does not meet the requirements for endoscopy, failing to achieve the goal of precision medicine. Optionally, the focal length of the optical system can be 3mm, 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, or 100mm.

[0049] In one embodiment, the optical system satisfies the condition: TTL ≤ 11 mm; where TTL is the distance along the optical axis from the object side of the first lens to the imaging surface of the optical system. When the optical system satisfies the above condition, its length is appropriate, avoiding pressure on the endoscope's spatial configuration and preventing compression of other parts, resulting in good stability. When TTL > 11 mm, the total length of the optical system is too large, easily increasing pressure on the endoscope's spatial configuration, potentially compressing other parts, and reducing the stability of the optical system itself. Optionally, the specific value of TTL can be 8 mm, 8.2 mm, 8.5 mm, 8.8 mm, 9 mm, 9.5 mm, 10 mm, 10.2 mm, 10.5 mm, 10.8 mm, or 11 mm.

[0050] In one embodiment, the optical system satisfies the condition: 4mm≤|R9+R10+R12|≤50mm; where R9 is the radius of curvature of the object side of the fifth lens at the optical axis, R10 is the radius of curvature of the image side of the fifth lens at the optical axis, and R12 is the radius of curvature of the image side of the sixth lens at the optical axis.

[0051] It is understandable that the fifth and sixth lenses are combined to form the second cemented lens, and the radius of curvature of the image side of the fifth lens at the optical axis is the same as the radius of curvature of the object side of the sixth lens at the optical axis.

[0052] When the optical system satisfies the above conditions, controlling the radius of curvature of the second cemented lens within a reasonable range helps control the aberrations generated by the fixed lens group, improving the imaging quality of the optical system and reducing transverse aberration. It also helps to reasonably constrain the surface shape of the fifth to sixth lenses, reducing the difficulty of molding and processing. When the value of |R9+R10+R12| is too large or too small, it may lead to an increase in transverse aberration, reducing the imaging quality of the optical system and increasing manufacturing difficulty and cost. Optionally, the values ​​of |R9+R10+R12| can be 4mm, 4.227mm, 5mm, 11.651mm, 18mm, 21mm, 25mm, 28mm, 32mm, 36mm, 40mm, 45mm, 47.8mm, and 50mm.

[0053] In one embodiment, the optical system satisfies the condition: 0.8mm≤|R13+R14+R16|≤25mm; where R13 is the radius of curvature of the object side of the seventh lens at the optical axis, R14 is the radius of curvature of the image side of the seventh lens at the optical axis, and R16 is the radius of curvature of the image side of the eighth lens at the optical axis.

[0054] Understandably, the seventh and eighth lenses are combined to form the third cemented lens, and the radius of curvature of the image side of the seventh lens at the optical axis is the same as the radius of curvature of the object side of the eighth lens at the optical axis.

[0055] When the optical system satisfies the above conditions, controlling the radius of curvature of the third cemented lens within a reasonable range helps control the aberrations generated by the fixed lens group, improving the imaging quality of the optical system and reducing transverse aberration. It also helps to reasonably constrain the surface shape of the seventh to eighth lenses, reducing the difficulty of molding and processing. When the value of |R13+R14+R16| is too large or too small, it may lead to an increase in transverse aberration, reducing the imaging quality of the optical system and increasing manufacturing difficulty and cost. Optionally, the value of |R13+R14+R16| can be 0.8mm, 0.852mm, 1.1mm, 3mm, 5mm, 8mm, 10.088mm, 12mm, 15mm, 18mm, 21mm, 23.1mm, or 25mm.

[0056] In one embodiment, the optical system satisfies the condition: 1.5mm≤g1≤3mm; where g1 is the distance on the optical axis from the object side of the ninth lens to the image side of the tenth lens.

[0057] When the optical system satisfies the above conditions, by rationally configuring the total thickness of the movable lens group, it is beneficial to shorten the overall length of the optical system and control the thickness of the lenses in the movable lens group within a reasonable range. This saves materials and ensures good manufacturability. When the value of g1 is too large or too small, it can easily cause uneven distribution of the thickness and spacing of the lenses in each lens group of the optical system, increasing the assembly difficulty. Optionally, the value of g1 can be 1.5mm, 1.73mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm, 2.6mm, 2.72mm, 2.75mm, 2.8mm, or 3mm.

[0058] First Embodiment

[0059] Please refer to Figure 1 The optical system of this embodiment has a fixed lens group and a movable lens group. The fixed lens group includes a first lens L1 to an eighth lens L8, and the movable lens group includes a ninth lens L9 and a tenth lens L10. The system comprises, sequentially from the object side to the image side along the optical axis:

[0060] The first lens L1 has positive optical power. The object side S1 of the first lens L1 is a plane, and the image side S2 of the first lens L1 is a convex surface near the optical axis.

[0061] The second lens L2 has negative optical power. The object side S3 of the second lens L2 is concave near the optical axis, and the image side S4 of the second lens L2 is convex near the optical axis.

[0062] The third lens L3 has positive optical power. The object side S5 of the third lens L3 is convex near the optical axis, and the image side S6 of the third lens L3 is concave near the optical axis.

[0063] The fourth lens L4 has negative optical power. The object side S7 and image side S8 of the fourth lens L4 are both concave near the optical axis.

[0064] The fifth lens L5 has negative optical power. The object side S9 and image side S10 of the fifth lens L5 are both convex near the optical axis.

[0065] The sixth lens L6 has positive optical power. The object side S11 and image side S12 of the sixth lens L6 are both convex near the optical axis.

[0066] Filter E. The filter has an object-side surface SE1 (not shown) and an image-side surface SE2 (not shown).

[0067] The seventh lens L7 has positive optical power. The object side S13 and image side S14 of the seventh lens L7 are both concave near the optical axis.

[0068] The eighth lens L8 has positive optical power. The object side S15 and image side S16 of the eighth lens L8 are both concave near the optical axis.

[0069] The ninth lens L9 has positive optical power. The object-side surface S17 of the ninth lens L9 is convex near the optical axis, and the image-side surface S18 of the ninth lens L9 is concave near the optical axis.

[0070] The tenth lens L10 has negative optical power. The object-side surface S19 of the tenth lens L10 is concave near the optical axis, and the image-side surface S20 of the tenth lens L10 is flat.

[0071] The materials of the first lens L1 to the tenth lens L10 are plastic or glass.

[0072] In addition, the optical system also includes an aperture stop STO (not shown), a camera protective glass G (not shown), and an image plane S21.

[0073] The aperture stop STO is positioned between the sixth lens L6 and the seventh lens L7 to control the amount of light entering the lens. In other embodiments, the aperture stop STO may also be positioned between other adjacent lenses or on other lenses.

[0074] The filter E is positioned between the sixth lens L6 and the seventh lens L7 to selectively transmit infrared light of a specific wavelength. The protective glass G is positioned on the side of the tenth lens L10 facing away from the ninth lens L9 to prevent biological contaminants such as blood, tissue fragments, and body fluids from directly contacting the image sensor, thus avoiding corrosion or biofilm adhesion. It also protects against physical impacts such as collisions with surgical instruments and friction from tubing, preventing the sensor from being scratched or broken.

[0075] The protective glass G has an object-side surface SG1 (not shown) and an image-side surface SG2 (not shown). The image surface S21 is the surface where the image formed after the light from the photographed object passes through the optical system.

[0076] Table 1 shows the characteristics of the optical system in this embodiment. The units for radius of curvature and thickness are millimeters (mm).

[0077] Table 1

[0078]

[0079]

[0080] Where F is the effective focal length of the optical system, FOV is the maximum field of view of the optical system in the diagonal direction, and TTL is the distance on the optical axis from the object side of the first lens to the imaging surface of the optical system.

[0081] Second Embodiment

[0082] The optical system of this embodiment has a fixed lens group and a movable lens group. The fixed lens group includes a first lens L1 to an eighth lens L8, and the movable lens group includes a ninth lens L9 and a tenth lens L10. The system comprises, sequentially from the object side to the image side along the optical axis:

[0083] The first lens L1 has positive optical power. The object side S1 of the first lens L1 is a plane, and the image side S2 of the first lens L1 is a convex surface near the optical axis.

[0084] The second lens L2 has negative optical power. The object side S3 of the second lens L2 is concave near the optical axis, and the image side S4 of the second lens L2 is convex near the optical axis.

[0085] The third lens L3 has positive optical power. The object side S5 of the third lens L3 is convex near the optical axis, and the image side S6 of the third lens L3 is concave near the optical axis.

[0086] The fourth lens L4 has negative optical power. The object side S7 and image side S8 of the fourth lens L4 are both concave near the optical axis.

[0087] The fifth lens L5 has positive optical power. The object side S9 of the fifth lens L5 is convex near the optical axis, and the image side S10 of the fifth lens L5 is concave near the optical axis.

[0088] The sixth lens L6 has negative optical power. The object-side surface S11 of the sixth lens L6 is concave near the optical axis, and the image-side surface S12 of the sixth lens L6 is convex near the optical axis.

[0089] Filter E. The filter has an object-side surface SE1 (not shown) and an image-side surface SE2 (not shown).

[0090] The seventh lens L7 has positive optical power. The object-side surface S13 of the seventh lens L7 is convex near the optical axis, and the image-side surface S14 of the seventh lens L7 is concave near the optical axis.

[0091] The eighth lens L8 has positive optical power. The object side S15 and image side S16 of the eighth lens L8 are both concave near the optical axis.

[0092] The ninth lens L9 has positive optical power. The object-side surface S17 of the ninth lens L9 is convex near the optical axis, and the image-side surface S18 of the ninth lens L9 is concave near the optical axis.

[0093] The tenth lens L10 has negative optical power. The object-side surface S19 of the tenth lens L10 is concave near the optical axis, and the image-side surface S20 of the tenth lens L10 is flat.

[0094] The first lens L1 to the tenth lens L10 are made of plastic or glass. Furthermore, the optical system also includes an aperture stop STO, a camera protective glass G, and an image plane S21. The arrangement of the aperture stop STO, the camera protective glass G, and the image plane S21 is as described in the first embodiment.

[0095] Table 2 shows the characteristics of the optical system in this embodiment. The units for radius of curvature and thickness are millimeters (mm).

[0096] Table 2

[0097]

[0098]

[0099] Third Embodiment

[0100] The optical system of this embodiment has a fixed lens group and a movable lens group. The fixed lens group includes a first lens L1 to an eighth lens L8, and the movable lens group includes a ninth lens L9 and a tenth lens L10. The system comprises, sequentially from the object side to the image side along the optical axis:

[0101] The first lens L1 has positive optical power. The object side S1 of the first lens L1 is a plane, and the image side S2 of the first lens L1 is a convex surface near the optical axis.

[0102] The second lens L2 has negative optical power. The object side S3 of the second lens L2 is concave near the optical axis, and the image side S4 of the second lens L2 is convex near the optical axis.

[0103] The third lens L3 has positive optical power. The object side S5 of the third lens L3 is convex near the optical axis, and the image side S6 of the third lens L3 is concave near the optical axis.

[0104] The fourth lens L4 has negative optical power. The object side S7 and image side S8 of the fourth lens L4 are both concave near the optical axis.

[0105] The fifth lens L5 has negative optical power. The object side S9 and image side S10 of the fifth lens L5 are both convex near the optical axis.

[0106] The sixth lens L6 has negative optical power. The object side S11 and image side S12 of the sixth lens L6 are both convex near the optical axis.

[0107] Filter E. The filter has an object-side surface SE1 (not shown) and an image-side surface SE2 (not shown).

[0108] The seventh lens L7 has positive optical power. The object-side surface S13 of the seventh lens L7 is convex near the optical axis, and the image-side surface S14 of the seventh lens L7 is concave near the optical axis.

[0109] The eighth lens L8 has positive optical power. The object side S15 and image side S16 of the eighth lens L8 are both concave near the optical axis.

[0110] The ninth lens L9 has positive optical power. The object-side surface S17 of the ninth lens L9 is convex near the optical axis, and the image-side surface S18 of the ninth lens L9 is concave near the optical axis.

[0111] The tenth lens L10 has negative optical power. The object-side surface S19 of the tenth lens L10 is concave near the optical axis, and the image-side surface S20 of the tenth lens L10 is flat.

[0112] The first lens L1 to the tenth lens L10 are made of plastic or glass. Furthermore, the optical system also includes an aperture stop STO, a camera protective glass G, and an image plane S21. The arrangement of the aperture stop STO, the camera protective glass G, and the image plane S21 is as described in the first embodiment.

[0113] Table 3 shows the characteristics of the optical system in this embodiment. The units for radius of curvature and thickness are millimeters (mm).

[0114] Table 3

[0115]

[0116] Table 4 shows the values ​​of F, FOV, TTL, |R9+R10+R12|, |R13+R14+R16)|, and g1 for the optical systems of the first to third embodiments.

[0117] Table 4

[0118] First Embodiment 120°～170° 0.98 10.687 4.227 10.088 2.75 Second Embodiment 120°～170° 1.31 10.687 11.651 0.852 2.72 Third Embodiment 120°～170° 1.26 10.687 47.8 23.1 1.73

[0119] As shown in Table 4, each embodiment satisfies the following conditions: 120°≤FOV≤175°, 3mm≤F≤100mm, TTL≤11mm, 4mm≤|R9+R10+R12|≤50mm, 0.8mm≤|R13+R14+R16|≤25mm, and 1.5mm≤g1≤3mm.

[0120] In the description of the embodiments of this utility model, it should be noted that the orientation or positional relationship of the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and other indicators are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0121] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Those skilled in the art can understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present utility model are still within the scope of the present utility model.

Claims

1. An optical system, characterized in that, The optical system comprises ten lenses with optical power, arranged sequentially from the object side to the image side along the optical axis: A fixed lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from the object side to the image side along the optical axis. A movable lens group includes a ninth lens and a tenth lens arranged sequentially from the object side to the image side along the optical axis. The ninth lens and the tenth lens are combined to form a movable cemented lens. The movable lens group is capable of moving along the optical axis. The optical system satisfies the condition: 120°≤FOV≤175°; Wherein, FOV is the maximum field of view in the diagonal direction of the optical system.

2. The optical system according to claim 1, characterized in that, The first lens has negative optical power; The second lens and the third lens are combined to form a first cemented lens, which has positive optical power; The fourth lens has negative optical power; The fifth lens and the sixth lens are combined to form a second cemented lens, and the seventh lens and the eighth lens are combined to form a third cemented lens. The combined optical power of the second cemented lens and the third cemented lens is positive.

3. The optical system according to claim 2, characterized in that, The optical system also includes a filter; The filter is disposed between the second cemented lens and the third cemented lens, or the filter is disposed on the side of the second cemented lens facing away from the third cemented lens, or the filter is disposed on the side of the third cemented lens facing away from the second cemented lens.

4. The optical system according to claim 1, characterized in that, The object-side surface of the ninth lens is convex near the optical axis, and the image-side surface is concave near the optical axis. The object-side surface of the tenth lens is concave near the optical axis.

5. The optical system according to claim 1, characterized in that, The optical system satisfies the condition: 3mm≤F≤100mm; Wherein, F represents the focal length of the optical system.

6. The optical system according to claim 1, characterized in that, The optical system satisfies the condition: TTL≤11mm; Wherein, TTL is the distance on the optical axis from the side of the first lens to the imaging surface of the optical system.

7. The optical system according to claim 1, characterized in that, The optical system satisfies the condition: 4mm≤|R9+R10+R12|≤50mm; Wherein, R9 is the radius of curvature of the object side of the fifth lens at the optical axis, R10 is the radius of curvature of the image side of the fifth lens at the optical axis, and R12 is the radius of curvature of the image side of the sixth lens at the optical axis.

8. The optical system according to claim 1, characterized in that, The optical system satisfies the condition: 0.8mm≤|R13+R14+R16|≤25mm; Wherein, R13 is the radius of curvature of the object side of the seventh lens at the optical axis, R14 is the radius of curvature of the image side of the seventh lens at the optical axis, and R16 is the radius of curvature of the image side of the eighth lens at the optical axis.

9. The optical system according to claim 1, characterized in that, The optical system satisfies the condition: 1.5mm≤g1≤3mm; Wherein, g1 is the distance on the optical axis from the object side of the ninth lens to the image side of the tenth lens.

10. An endoscope, characterized in that, It includes an electronic photosensitive element and an optical system as described in any one of claims 1 to 9, wherein the electronic photosensitive element is disposed on the image side of the optical system.

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