Endoscope equipment

Abstract

The invention discloses endoscope equipment, which comprises an adapter and a camera which form an imaging system, and is characterized in that the adapter comprises a first lens group, a second lens group and a third lens group which are coaxially arranged in sequence from an object side to an image side; the first lens group has positive focal power and comprises a first lens and a second lens which are coaxially arranged in sequence from the object side to the image side; the second lens group has negative focal power and comprises a third lens, a fourth lens and a fifth lens which are sequentially and coaxially arranged from the object side to the image side; the third lens group has positive focal power; the imaging system satisfies 1.2 < = f1 / f < = 2, f2 / f > = 20,-0.8 < = f3 / f < =-1.5, f4 / f < =-4, f5 / f < =-2, and 0.5 < = f6 / f < = 0.9. A positive-negative-positive optical structure can reduce aberration; the relational expressions of the focal lengths can ensure that the focal lengths are not too small while the achromatism of the lens is ensured, and materials with lower dispersion coefficients are not needed, so that the color reducibility is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly relates to an endoscope device. Background Art

[0002] An endoscope device inputs the endoscope image into a computer for digital processing and displays the image in real time to facilitate doctors' observation. The quality of the surgery is related to the life and health of the patient, and the importance of the image effect of the endoscope device is self-evident. In the existing imaging systems, most aim to improve the imaging quality of the lens, and generally materials with a high refractive index and a low dispersion coefficient are selected, resulting in inconsistent transmittance for different wavelengths and causing color distortion, that is, low color reducibility. Summary of the Invention

[0003] The present invention discloses an endoscope device for improving color reducibility on the basis of ensuring imaging quality.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] An endoscope device includes an adapter and a camera. The camera and the adapter form the imaging system of the endoscope device. The adapter includes a first lens group, a second lens group, and a third lens group that are coaxially arranged in sequence from the object side to the image side;

[0006] The first lens group has a positive optical power and includes a first lens and a second lens that are coaxially arranged in sequence from the object side to the image side;

[0007] The second lens group has a negative optical power and includes a third lens, a fourth lens, and a fifth lens that are coaxially arranged in sequence from the object side to the image side;

[0008] The third lens group has a positive optical power;

[0009] The imaging system satisfies the following conditional formula:

[0010] 1.2 ≤ f1 / f ≤ 2, f2 / f ≥ 20, -0.8 ≤ f3 / f ≤ -1.5, f4 / f ≤ -4, f5 / f ≤ -2, 0.5 ≤ f6 / f ≤ 0.9;

[0011] Wherein, f1 is the focal length of the first lens; f2 is the focal length of the second lens; f3 is the focal length of the third lens; f4 is the focal length of the fourth lens; f5 is the focal length of the fifth lens; f6 is the focal length of the third lens group; f is the focal length of the imaging system.

[0012] The adapter and the camera in the above endoscope device form an imaging system of the endoscope device. The adapter includes three lens groups, namely a first lens group, a second lens group, and a third lens group. Moreover, the first lens group has a positive optical power, the second lens group has a negative optical power, and the third lens group has a positive optical power. Adopting a positive-negative-positive optical structure, where light converges first, then diverges, and finally converges, can prevent the deflection angle of light in each group from being too large, thus reducing aberration. Each lens group contains multiple lenses, further reducing the deflection angle of light, and thus overall reducing the aberration of the optical system. At the same time, the relationship between the focal lengths of each lens can ensure that the lenses are achromatic while the focal lengths are not too small, without the need to use materials with a low dispersion coefficient, ensuring that the transmittance in the entire wavelength band is relatively consistent, and thus improving color reproducibility. The endoscope device provided by the present invention not only focuses on imaging quality but also on color reduction performance, comprehensively improving the image effect of the endoscope device and increasing more possibilities for the success of the surgery.

[0013] In some embodiments, the first lens is a convex lens, and the object side surface of the first lens is convex near the optical axis.

[0014] The second lens is a meniscus lens, and the object side surface of the second lens is convex near the optical axis, and the image side surface of the second lens is concave near the optical axis.

[0015] In some embodiments, the second lens is a cemented lens formed by coaxially arranging a first sub-lens and a second sub-lens in sequence from the object side to the image side, and the center of the cemented surface of the second lens faces the object side or the center of the cemented surface of the second lens faces the image side.

[0016] And / or, the second lens is a spherical lens or an aspherical lens.

[0017] In some embodiments, the object side surface of the third lens is concave near the optical axis, and the image side surface of the third lens is concave near the optical axis.

[0018] The object side surface of the fourth lens is concave near the optical axis, and the image side surface of the fourth lens is convex near the optical axis.

[0019] The object side surface of the fifth lens is concave near the optical axis, and the image side surface of the fifth lens is convex near the optical axis.

[0020] In some embodiments, the fourth lens is a cemented lens formed by coaxially arranging a third sub-lens and a fourth sub-lens in sequence from the object side to the image side, and the center of the cemented surface of the fourth lens faces the object side or the center of the cemented surface of the fourth lens faces the image side.

[0021] Alternatively, the fifth lens is a cemented lens formed by coaxially arranging a fifth sub-lens and a sixth sub-lens in sequence from the object side to the image side, and the center of the cemented surface of the fifth lens faces the object side or the center of the cemented surface of the fifth lens faces the image side;

[0022] Alternatively, the fifth lens is a cemented lens formed by coaxially arranging a seventh sub-lens, an eighth sub-lens, and a ninth sub-lens in sequence from the object side to the image side. The center of the cemented surface of the seventh sub-lens and the eighth sub-lens faces the image side, and the center of the cemented surface of the eighth sub-lens and the ninth sub-lens faces the object side.

[0023] In some embodiments, the fourth lens is a spherical lens or an aspherical lens;

[0024] And / or, the fifth lens is a spherical lens or an aspherical lens.

[0025] In some embodiments, the third lens group is a biconvex lens or a plano-convex lens;

[0026] Alternatively, the camera further includes a fourth lens group with a zero optical power. The fourth lens group includes a filter. When there are two filters, the fourth lens group further includes a beam splitter prism.

[0027] In some embodiments, the imaging system satisfies the following conditional formula:

[0028] L1 / L ≤ 0.4;

[0029] Wherein, L1 is the total thickness of the non-planar lenses in the imaging system, and L is the total length of the imaging system;

[0030] And / or, the imaging system satisfies the following conditional formula:

[0031] L2 / L1 ≤ 0.2;

[0032] Wherein, L1 is the total thickness of the non-planar lenses in the imaging system, and L2 is the total thickness of the air between the non-planar lenses in the imaging system.

[0033] In some embodiments, the imaging system satisfies the following conditional formula:

[0034] r1 / f ≥ 0.4;

[0035] Wherein, r1 is the radius of curvature of the object side surface of the first lens, and f is the focal length of the imaging system.

[0036] In some embodiments, the dispersion coefficients of the optical materials used in the imaging system are all greater than 35;

[0037] Alternatively, the dispersion coefficients of the optical materials used in the imaging system are all greater than or equal to 40. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 FIG. 1 is a schematic structural diagram of an endoscope device provided by an embodiment of the present invention;

[0039] Figure 2 FIG. 2 is a schematic structural diagram of an imaging system provided by an embodiment of the present invention;

[0040] Figure 3 FIG. 3 is an optical path diagram of an imaging system provided by an embodiment of the present invention;

[0041] Figure 4 FIG. 4 is a schematic structural diagram of another imaging system provided by an embodiment of the present invention;

[0042] Figure 5 FIG. 5 is an optical path diagram of another imaging system provided by an embodiment of the present invention;

[0043] Figure 6 FIG. 6 is a schematic structural diagram of a first lens;

[0044] Figures 7 - 9 FIGS. 7A and 7B are schematic structural diagrams of a second lens;

[0045] Figure 10 FIG. 8 is a schematic structural diagram of a third lens;

[0046] Figures 11 - 13 FIGS. 9A and 9B are schematic structural diagrams of a fourth lens;

[0047] Figures 14 - 16 FIGS. 10A and 10B are schematic structural diagrams of a fifth lens;

[0048] Figures 17 - 18 FIGS. 11A and 11B are schematic structural diagrams of a third lens group;

[0049] Figure 19 FIG. 12 is a simulation diagram of the modulation transfer function of an imaging system provided by the present invention;

[0050] Figure 20 FIG. 13 is a chromatic aberration diagram of an imaging system provided by the present invention;

[0051] Figure 21 FIG. 14 is a distortion diagram of an imaging system provided by the present invention;

[0052] Figure 22 FIG. 15 is a schematic diagram of the distortion rate of an imaging system provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] First, the application scenario of this application will be introduced: For traditional endoscope devices, most aim to improve the imaging quality of the lens. Generally, materials with a high refractive index and a low dispersion coefficient are selected, resulting in inconsistent transmittance for different wavelengths and causing color distortion, that is, low color reducibility. If materials with a low dispersion coefficient are not used, the aberration correction is generally relatively large, resulting in poor imaging effects.

[0054] Based on the above application scenario, the embodiment of this application provides an endoscope device, which can ensure relatively consistent transmittance across the entire wavelength band without using materials with a low dispersion coefficient, thus improving color reducibility.

[0055] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Among them, in the description of the embodiments of this application, unless otherwise specified, " / " means "or". For example, A / B can mean A or B; "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "a plurality of" means two or more than two.

[0056] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as implying or suggesting relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of this application, unless otherwise specified, the meaning of "a plurality of" is two or more than two.

[0057] As Figures 1 - 5 shown, the embodiment of the present invention provides an endoscope device, including endoscope A, adapter B, and camera C. Adapter B and camera C form the imaging system of the endoscope device. Endoscope A is inserted into the human body, and endoscope A and adapter B are connected by an optical cable. The imaging system composed of adapter B and camera C captures the optical information conducted by the endoscope. Adapter B includes a first lens group 1, a second lens group 2, and a third lens group 3 arranged coaxially in sequence from the object side to the image side;

[0058] The first lens group 1 has a positive optical power and includes a first lens 11 and a second lens 12 arranged coaxially in sequence from the object side to the image side;

[0059] The second lens group 2 has a negative optical power and includes a third lens 21, a fourth lens 22, and a fifth lens 23 that are coaxially arranged in sequence from the object side to the image side;

[0060] The third lens group 3 has a positive optical power;

[0061] The imaging system satisfies the following conditional expressions:

[0062] 1.2 ≤ f1 / f ≤ 2, f2 / f ≥ 20, -0.8 ≤ f3 / f ≤ -1.5, f4 / f ≤ -4, f5 / f ≤ -2, 0.5 ≤ f6 / f ≤ 0.9;

[0063] Wherein, f1 is the focal length of the first lens 11; f2 is the focal length of the second lens 12; f3 is the focal length of the third lens 21; f4 is the focal length of the fourth lens 22; f5 is the focal length of the fifth lens 23; f6 is the focal length of the third lens group 3; f is the focal length of the imaging system.

[0064] The adapter B and the camera C in the above endoscopic device form the imaging system of the endoscopic device. The adapter B includes three lens groups, namely the first lens group 1, the second lens group 2, and the third lens group 3. And the first lens group 1 has a positive optical power, the second lens group 2 has a negative optical power, and the third lens group 3 has a positive optical power. Adopting a positive-negative-positive optical structure, allowing the light to converge first, then diverge, and finally converge, can make the deflection angle of the light in each group not too large, so the aberration can be reduced; each lens group contains multiple lenses, further reducing the deflection angle of the light, thus reducing the aberration of the optical system as a whole. At the same time, the relational expressions of each focal length can ensure that the lenses are achromatic while the focal length is not too small, without the need to use materials with a small dispersion coefficient, ensuring that the transmittance in the entire wavelength band is relatively consistent, thus improving the color reducibility. The endoscopic device provided by the present invention not only pays attention to the imaging quality but also pays attention to the color reduction performance. Applied to the endoscopic shooting system, it comprehensively improves the image effect of the endoscopic device and increases more possibilities for the success of the operation.

[0065] In some embodiments, the camera C further includes a fourth lens group 4 with zero optical power. The fourth lens group 4 includes a filter 41. When there are two filters 41, the fourth lens group 4 further includes a beam splitter prism 42.

[0066] In a possible implementation manner, the imaging system includes a diaphragm S1, a first lens group 1, a second lens group 2, a third lens group 3, and a fourth lens group 4 that are coaxially arranged in sequence from the object side to the image side. The first lens group 1 has a positive optical power, the second lens group 2 has a negative optical power, the third lens group 3 has a positive optical power. The fourth lens group 4 has an optical power of 0. As Figures 2 - 5 shown. The optical path of the endoscopic device provided by the embodiment of the present invention can be in the visible light band, such asFigure 2 and Figure 3 As shown, it can also be a dual-band of visible light and near-infrared light, such as Figure 4 and Figure 5 shown.

[0067] It can be understood that the diaphragm S1 is an essential part of the optical system and is placed at the very front end of the optical system. The first lens group 1 includes a first lens 11 and a second lens 12 arranged coaxially in sequence from the object side to the image side. The focal length f1 of the first lens 11 and the focal length f of the imaging system satisfy 1.2 ≤ f1 / f ≤ 2, that is, f1 / f can be any value within the range of [1.2, 2]. For example, the value can be 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, etc. The focal length f2 of the second lens 12 and the focal length f of the imaging system satisfy f2 / f ≥ 20, that is, f2 / f can be 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, etc. The second lens group 2 includes a third lens 21, a fourth lens 22, and a fifth lens 23 arranged coaxially in sequence from the object side to the image side. The focal length f3 of the third lens 21 and the focal length f of the imaging system satisfy -0.8 ≤ f3 / f ≤ -1.5, that is, f3 / f can be any value within the range of [-0.8, -1.5]. For example, the value can be -0.8, -0.9, -1.0, -1.1, -1.2, -1.3, -1.4, -1.5, etc. The focal length f4 of the fourth lens 22 and the focal length f of the imaging system satisfy f4 / f ≤ -4, that is, f4 / f can be -7.5, -7, -6.5, -6, -5.5, -5.0, -4.5, -4, etc. The focal length f5 of the fifth lens 23 and the focal length f of the imaging system satisfy f5 / f ≤ -2, that is, f4 / f can be -7.5, -7, -6.5, -6, -5.5, -5.0, -4.5, -4, -3.5, -3, -2.5, -2, etc. The focal length f6 of the third lens group 3 and the focal length f of the imaging system satisfy 0.5 ≤ f6 / f ≤ 0.9, that is, f6 / f can be any value within the range of [0.5, 0.9]. For example, the value can be 0.5, 0.6, 0.7, 0.8, 0.9, etc. As Figure 4 and Figure 5 shown, the fourth lens group 4 can realize the functions of focusing, beam splitting, and filtering of the imaging system, and includes a beam splitting prism 42 and several filter films 41. The bonding surface of the beam splitting prism 42 is coated with a beam splitting film, so that the beam splitting function in the visible light band and the near-infrared band can be realized, and finally the visible light is imaged on the image side S20, and the near-infrared light is imaged on the image side S21.

[0068] It can be understood that, based on the above focal length relationship, and considering that the lens thickness and the interval between lenses are relatively small, through optical calculations, the target focal length and the target optical back focal length of the imaging system can be obtained.

[0069] In some embodiments, the first lens 11 is a convex lens, and the object side surface of the first lens 11 is convex near the optical axis; the second lens 12 is a meniscus lens, and the object side surface of the second lens 12 is convex near the optical axis, and the image side surface of the second lens 12 is concave near the optical axis.

[0070] In a possible implementation manner, the first lens group 1 includes a first lens 11 and a second lens 12 arranged coaxially in sequence from the object side to the image side. Among them, the first lens 11 is a convex lens, the object side surface S2 of the first lens 11 is convex near the optical axis, and the image side surface S3 of the first lens 11 is flat near the optical axis, as Figure 6 shown. The second lens 12 is a meniscus lens, and the object side surface S4 of the second lens 12 is convex near the optical axis, and the image side surface S6 of the second lens 12 is concave near the optical axis, as Figures 7 - 9 shown.

[0071] In some embodiments, the second lens 12 is a cemented lens formed by cementing a first sub-lens 121 and a second sub-lens 122 arranged coaxially in sequence from the object side to the image side, and the center of the cemented surface of the second lens 12 faces the object side or the center of the cemented surface of the second lens 12 faces the image side;

[0072] and / or, the second lens 12 is a spherical lens or an aspherical lens.

[0073] In a possible implementation manner, as Figure 7 and Figure 8 shown, the second lens 12 is a cemented lens formed by cementing a first sub-lens 121 and a second sub-lens 122 arranged coaxially in sequence from the object side to the image side. As Figure 7 shown, the object side surface S4 of the first sub-lens 121 is convex near the optical axis, the center of the cemented surface S5 of the first sub-lens 121 and the second sub-lens 122 faces the image side, and the image side surface S6 of the second sub-lens 122 is concave near the optical axis. As Figure 8 shown, the object side surface S4 of the first sub-lens 121 is convex near the optical axis, the center of the cemented surface S5 of the first sub-lens 121 and the second sub-lens 122 faces the object side, and the image side surface S6 of the second sub-lens 122 is concave near the optical axis.

[0074] In a possible implementation manner, as Figure 9 shown, the second lens 12 is a meniscus lens, the object side surface S4 of the second lens 12 is convex near the optical axis, and the image side surface S6 of the second lens 12 is concave near the optical axis.

[0075] In a possible implementation, the second lens 12 can be a spherical cemented lens, such as Figure 7 and Figure 8 shown, or it can be a single-piece aspherical lens, such as Figure 9 shown.

[0076] In some embodiments, the object side surface of the third lens 21 is concave near the optical axis, and the image side surface of the third lens 21 is concave near the optical axis;

[0077] The object side surface of the fourth lens 22 is concave near the optical axis, and the image side surface of the fourth lens 22 is convex near the optical axis;

[0078] The object side surface of the fifth lens 23 is concave near the optical axis, and the image side surface of the fifth lens 23 is convex near the optical axis.

[0079] In a possible implementation, the second lens group 2 includes a third lens 21, a fourth lens 22, and a fifth lens 23 that are coaxially arranged in sequence from the object side to the image side. Among them, the third lens 21 is a biconcave lens. The object side surface S7 of the third lens 21 is concave near the optical axis, and the image side surface S8 of the third lens 21 is concave near the optical axis, such as Figure 10 shown. The object side surface S9 of the fourth lens 22 is concave near the optical axis, and the image side surface S11 of the fourth lens 22 is convex near the optical axis, such as Figures 11 - 13 shown. The object side surface S12 of the fifth lens 23 is concave near the optical axis, and the image side surface S14 of the fifth lens 23 is convex near the optical axis, such as Figures 14 - 16 shown.

[0080] In some embodiments, the fourth lens 22 is a cemented lens formed by coaxially arranging a third sub-lens 221 and a fourth sub-lens 222 in sequence from the object side to the image side. The center of the cemented surface of the fourth lens 22 faces the object side or the center of the cemented surface of the fourth lens 22 faces the image side;

[0081] Alternatively, the fifth lens 23 is a cemented lens formed by coaxially arranging a fifth sub-lens 231 and a sixth sub-lens 232 in sequence from the object side to the image side. The center of the cemented surface of the fifth lens 23 faces the object side or the center of the cemented surface of the fifth lens 23 faces the image side;

[0082] Alternatively, the fifth lens 23 is a cemented lens formed by coaxially arranging a seventh sub-lens 233, an eighth sub-lens 234, and a ninth sub-lens 235 in sequence from the object side to the image side. The center of the cemented surface between the seventh sub-lens 233 and the eighth sub-lens 234 faces the image side, and the center of the cemented surface between the eighth sub-lens 234 and the ninth sub-lens 235 faces the object side.

[0083] In a possible implementation, such as Figure 11 and Figure 12As shown, the fourth lens 22 is a cemented lens formed by coaxially arranging a third sub-lens 221 and a fourth sub-lens 222 in sequence from the object side to the image side. As Figure 11 shown, the object side surface S9 of the third sub-lens 221 is concave near the optical axis, the center of the cemented surface S10 of the third sub-lens 221 and the fourth sub-lens 222 faces the image side, and the image side surface S11 of the fourth sub-lens 222 is convex near the optical axis. As Figure 12 shown, the object side surface S9 of the third sub-lens 221 is concave near the optical axis, the center of the cemented surface S10 of the third sub-lens 221 and the fourth sub-lens 222 faces the object side, and the image side surface S11 of the fourth sub-lens 222 is convex near the optical axis.

[0084] In a possible implementation, as Figure 13 shown, the fourth lens 22 is a meniscus lens, the object side surface S9 of the fourth lens 22 is concave near the optical axis, and the image side surface S11 of the fourth lens 22 is convex near the optical axis.

[0085] In a possible implementation, as Figure 14 and Figure 15 shown, the fifth lens 23 is a cemented lens formed by coaxially arranging a fifth sub-lens 231 and a sixth sub-lens 232 in sequence from the object side to the image side. As Figure 14 shown, the object side surface S12 of the fifth sub-lens 231 is concave near the optical axis, the center of the cemented surface S13 of the fifth sub-lens 231 and the sixth sub-lens 232 faces the image side, and the image side surface S14 of the sixth sub-lens 232 is convex near the optical axis. As Figure 15 shown, the object side surface S12 of the fifth sub-lens 231 is concave near the optical axis, the center of the cemented surface S13 of the fifth sub-lens 231 and the sixth sub-lens 232 faces the object side, and the image side surface S14 of the sixth sub-lens 232 is convex near the optical axis. That is to say, the fifth lens 23 is a doublet lens.

[0086] In a possible implementation, as Figure 16 shown, the fifth lens 23 is a cemented lens formed by coaxially arranging a seventh sub-lens 233, an eighth sub-lens 234, and a ninth sub-lens 235 in sequence from the object side to the image side. The object side surface S12 of the seventh sub-lens 233 is concave near the optical axis, the center of the cemented surface S13a of the seventh sub-lens 233 and the eighth sub-lens 234 faces the image side, the center of the cemented surface S13b of the eighth sub-lens 234 and the ninth sub-lens 235 faces the object side, and the image side surface S14 of the ninth sub-lens 235 is convex near the optical axis. That is to say, the fifth lens 23 is a concave-convex-concave triplet lens.

[0087] In some embodiments, the fourth lens 22 is a spherical lens or an aspherical lens;

[0088] And / or, the fifth lens 23 is a spherical lens or an aspherical lens.

[0089] In a possible implementation manner, the fourth lens 22 may be a meniscus cemented lens or a single-piece meniscus aspherical lens.

[0090] In a possible implementation manner, the fifth lens 23 may be a meniscus cemented lens or a meniscus aspherical lens.

[0091] In some embodiments, the third lens group 3 is a biconvex lens or a plano-convex lens.

[0092] In a possible implementation manner, as Figure 17 shown, the third lens group 3 is a biconvex lens composed of a first convex lens and a second convex lens coaxially arranged in sequence from the object side to the image side. The object side surface S16 of the first convex lens is convex near the optical axis, the image side surface S17 of the first convex lens is convex near the optical axis, and the curvature of the image side surface S17 of the first convex lens is greater than the curvature of the object side surface S16 of the first convex lens. The object side surface S18 of the second convex lens is convex near the optical axis, the image side surface S19 of the second convex lens is convex near the optical axis, and the curvature of the object side surface S18 of the second convex lens is greater than the curvature of the image side surface S19 of the first convex lens.

[0093] In a possible implementation manner, as Figure 18 shown, the third lens group 3 is a plano-convex lens. The object side surface S16 of the plano-convex lens is convex near the optical axis, the image side surface S17 of the plano-convex lens is convex near the optical axis, and the curvature of the object side surface S18 of the plano-convex lens is greater than the curvature of the image side surface S19 of the plano-convex lens.

[0094] In the endoscope device provided by the embodiments of the present invention, as Figures 2 - 5As shown in the figure, the first lens group 1 has a positive optical power and includes a first lens 11 and a second lens 12 arranged coaxially in sequence from the object side to the image side; the second lens group 2 has a negative optical power and includes a third lens 21, a fourth lens 22, and a fifth lens 23 arranged coaxially in sequence from the object side to the image side; the third lens group 3 has a positive optical power and includes a single convex lens. In the entire endoscope device, the number of positive lenses and negative lenses is close, effectively eliminating spherical aberration, astigmatism, and distortion. When the second lens 12, the fourth lens 22, and the fifth lens 23 are cemented lenses, from f2 / f≥20, f4 / f≤-4, and f5 / f≤-2, it can ensure that while the lens achromatism is achieved, the focal length is not too small, without the need to use materials with a small dispersion coefficient. When the second lens 12, the fourth lens 22, and the fifth lens 23 are aspherical lenses, the aspherical coefficient helps to reduce aberration and can achieve the same effect. Because the chromatic aberration is eliminated to an extremely small degree, the endoscope device can accommodate a relatively wide spectrum, and the spectral width can reach 400 - 1000nm, and the imaging quality almost reaches the diffraction limit. The second lens 12, the fourth lens 22, and the fifth lens 23 are meniscus cemented lenses or meniscus aspherical lenses, and the curvature radii of the front surface and the rear surface are relatively close, which can better eliminate field curvature and distortion, making the imaging quality of the center and corners of the image plane more consistent.

[0095] In some embodiments, the imaging system satisfies the following conditional expressions:

[0096] L1 / L≤0.4;

[0097] wherein, L1 is the total thickness of the non-planar lenses in the imaging system, and L is the total length of the imaging system;

[0098] and / or, the imaging system satisfies the following conditional expressions:

[0099] L2 / L1≤0.2;

[0100] wherein, L1 is the total thickness of the non-planar lenses in the imaging system, and L2 is the total thickness of the air between the non-planar lenses in the imaging system.

[0101] It should be noted that let L1 be the total thickness of the non-planar lenses (i.e., the curvature of the lenses is not all 0) in the imaging system, L be the total length of the imaging system, and L1 / L≤0.4, which can be, for example, 0.4, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31, 0.3, etc. By this condition, the total thickness of the lenses is restricted, reducing the absorption of short-wavelength light energy by the lens material, thus improving the color reducibility of the imaging system.

[0102] It should also be noted that let L2 be the total thickness of the air between the non-planar lenses in the imaging system, and L2 / L1≤0.2. For example, it can be 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.1, etc. By restricting the air gap thickness with this condition, the imaging system can be made shorter. The gap between the non-planar lenses is very small, so the overall optical length can be controlled. As an example Figure 4 it can be seen that the gaps between the lenses are all very small, saving space.

[0103] In some embodiments, the imaging system satisfies the following conditional formula:

[0104] r1 / f≥0.4;

[0105] wherein, r1 is the curvature radius of the object side of the first lens 11, and f is the focal length of the imaging system.

[0106] In a possible implementation manner, as Figure 4 shown, the first lens 11 is a convex lens, the curvature radius of the object side S2 of the first lens 11 is r1, and r1 / f≥0.4. For example, it can be 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.5, etc. Limiting in this way can effectively reduce the incident angle of light, thereby reducing the aberration of the imaging system as a whole.

[0107] In some embodiments, the dispersion coefficients of the optical materials used in the imaging system are all greater than 35. Such materials have relatively consistent transmittance within the spectral range of optical design.

[0108] In some embodiments, the dispersion coefficients of the optical materials used in the imaging system are all greater than or equal to 40. The transmittance at 400 nm is greater than 95% per 10 mm, which is significantly higher than that of the currently used ZF52 material (the transmittance at 400 nm is only about 80% per 10 mm). By selecting materials, the difference in transmittance in different wavelength bands is reduced, thus avoiding the problem of color distortion caused by large differences in transmittance at different wavelengths and ensuring relatively high color reproducibility.

[0109] Figure 19 For the modulation transfer function (Modulation Transfer Function, abbreviated as MTF) of the endoscope device provided by the embodiments of the present invention, it can be seen that the imaging quality in the 400-1000 nm wide wavelength band almost reaches the diffraction limit. Figure 20 This is the chromatic aberration diagram, and it can be seen that the embodiments have chromatic aberration within the diffraction limit. Figure 21 This is the distortion diagram. From Figure 22 it can be known that the distortion is less than 1%, and the human eye cannot see the image deformation.

[0110] The endoscope device provided by the embodiment of the present invention improves the lens structure. Without using materials with low dispersion coefficients, it ensures that the transmittance in the entire wavelength band is relatively consistent, thereby improving color reproducibility. Moreover, it can also reduce aberration at the same time, and the overall optical length is short, thus comprehensively improving the image effect of the imaging system.

[0111] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these changes and modifications.

Claims

1. An endoscope device, characterized in that, It includes an adapter and a camera. The camera and the adapter form the imaging system of the endoscope device. The adapter includes a first lens group, a second lens group, and a third lens group that are coaxially arranged in sequence from the object side to the image side; The first lens group has a positive optical power and includes a first lens and a second lens that are coaxially arranged in sequence from the object side to the image side; The second lens group has a negative optical power and includes a third lens, a fourth lens, and a fifth lens that are coaxially arranged in sequence from the object side to the image side; The third lens group has a positive optical power; The imaging system satisfies the following conditional expressions: 1.2 ≤ f1 / f ≤ 2, f2 / f ≥ 20, -0.8 ≤ f3 / f ≤ -1.5, f4 / f ≤ -4, f5 / f ≤ -2, 0.5 ≤ f6 / f ≤ 0.9; Wherein, f1 is the focal length of the first lens; f2 is the focal length of the second lens; f3 is the focal length of the third lens; f4 is the focal length of the fourth lens; f5 is the focal length of the fifth lens; f6 is the focal length of the third lens group; f is the focal length of the imaging system.

2. The endoscope device according to claim 1, characterized in that The first lens is a convex lens, and the object side surface of the first lens is convex near the optical axis; The second lens is a meniscus lens, and the object side surface of the second lens is convex near the optical axis, and the image side surface of the second lens is concave near the optical axis.

3. The endoscopic device according to claim 2, characterized in that, The second lens is a cemented lens formed by coaxially arranging a first sub-lens and a second sub-lens in sequence from the object side to the image side. The center of the cemented surface of the second lens faces the object side or the center of the cemented surface of the second lens faces the image side; And / or, the second lens is a spherical lens or an aspherical lens.

4. The endoscopic device according to claim 1, wherein, The object side surface of the third lens is concave near the optical axis, and the image side surface of the third lens is concave near the optical axis; The object side surface of the fourth lens is concave near the optical axis, and the image side surface of the fourth lens is convex near the optical axis; The object side surface of the fifth lens is concave near the optical axis, and the image side surface of the fifth lens is convex near the optical axis.

5. The endoscope device according to claim 4, characterized in that, The fourth lens is a cemented lens formed by coaxially arranging a third sub-lens and a fourth sub-lens in sequence from the object side to the image side. The center of the cemented surface of the fourth lens faces the object side or the center of the cemented surface of the fourth lens faces the image side; Or, the fifth lens is a cemented lens formed by coaxially arranging a fifth sub-lens and a sixth sub-lens in sequence from the object side to the image side. The center of the cemented surface of the fifth lens faces the object side or the center of the cemented surface of the fifth lens faces the image side; Or, the fifth lens is a cemented lens formed by coaxially arranging a seventh sub-lens, an eighth sub-lens, and a ninth sub-lens in sequence from the object side to the image side. The center of the cemented surface between the seventh sub-lens and the eighth sub-lens faces the image side, and the center of the cemented surface between the eighth sub-lens and the ninth sub-lens faces the object side.

6. The endoscope device according to claim 4, wherein The fourth lens is a spherical lens or an aspherical lens; And / or, the fifth lens is a spherical lens or an aspherical lens.

7. The endoscopic device according to claim 1, wherein, The third lens group is a biconvex lens or a plano-convex lens; Alternatively, the camera includes a fourth lens group with a zero optical power, and the fourth lens group includes a filter. When there are two filters, the fourth lens group further includes a beam splitter prism.

8. The endoscopic device according to any one of claims 1-7, characterized in that, The imaging system satisfies the following conditional formula: L1 / L ≤ 0.4; wherein, L1 is the total thickness of the non-planar lenses in the imaging system, and L is the total length of the imaging system; and / or, the imaging system satisfies the following conditional formula: L2 / L1 ≤ 0.2; wherein, L1 is the total thickness of the non-planar lenses in the imaging system, and L2 is the total thickness of the air between the non-planar lenses in the imaging system.

9. The endoscopic device according to any one of claims 1-7, characterized in that, The imaging system satisfies the following conditional formula: r1 / f≥0.4； wherein, r1 is the curvature radius of the object side of the first lens, and f is the focal length of the imaging system.

10. The endoscopic device according to any one of claims 1-7, characterized in that, The dispersion coefficients of the optical materials used in the imaging system are all greater than 35; Alternatively, the dispersion coefficients of the optical materials used in the imaging system are all greater than or equal to 40.

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