Optical imaging lens group, coupler and endoscope

Abstract

The invention relates to an optical imaging lens group, a coupler and an endoscope. The optical imaging lens group comprises a front fixed group and a zoom group which are arranged along the direction of an optical axis. The front fixed group comprises a first lens group and a first negative lens, and the zoom group comprises a second lens group; the first lens group and the second lens group comprise a double-separation lens group and / or a double-bonding lens group. And the zoom group is used for changing the focal length of the optical imaging lens group under the condition of moving along the optical axis direction. The optical imaging lens group is beneficial to imaging.

Description

Technical Field

[0001] The present application relates to the technical field of endoscopes, and in particular to an optical imaging lens assembly, a coupler and an endoscope. Background Art

[0002] An endoscope is a commonly used medical device that is mainly used to observe lesions in the patient's body and provide images for clinical surgery and diagnosis.

[0003] The coupler is an important component in the endoscope. It is responsible for connecting the endoscope eyepiece and the detector, thereby transmitting the light signal detected by the endoscope eyepiece to the detector, and the detector forms an image based on the light signal output by the coupler. The optical imaging lens group is an important component of the coupler. Therefore, the design of the optical imaging lens group determines the imaging quality of the endoscope to a certain extent.

[0004] Therefore, how to design an optical imaging lens assembly that is conducive to imaging is a key research topic for people in this field. Summary of the invention

[0005] Based on this, it is necessary to provide an optical imaging lens set, a coupler and an endoscope that are conducive to imaging in order to solve the above-mentioned technical problems.

[0006] In a first aspect, the present application provides an optical imaging lens assembly, the optical imaging lens assembly comprising a front fixed group and a variable magnification group arranged along an optical axis direction;

[0007] The front fixed group includes a first lens group and a first negative lens, and the variable power group includes a second lens group; the first lens group and the second lens group include a double separated lens group and / or a double cemented lens group;

[0008] The zoom group is used to change the focal length of the optical imaging lens group while moving along the optical axis.

[0009] In one embodiment, the optical imaging lens assembly further includes a compensation group, and the variable magnification group is disposed between the front fixed group and the compensation group;

[0010] The compensation group includes a third lens group and a first positive lens, and the third lens group includes a double separated lens group and / or a double cemented lens group;

[0011] The compensation group is used to work in conjunction with the zoom group to change the focal length of the optical imaging lens group.

[0012] In one embodiment, the optical imaging lens assembly further includes a rear fixing group, and the compensation group is disposed between the zoom group and the rear fixing group;

[0013] The rear fixed group includes a fourth lens group and a second negative lens, and the fourth lens group includes a double separated lens group and / or a double cemented lens group.

[0014] In one embodiment, the first negative lens includes a biconcave lens with negative optical power, the first lens group includes a double cemented lens group, the double cemented lens group in the first lens group includes a first cemented lens, and the first cemented lens is arranged between the first negative lens and the zoom group.

[0015] In one embodiment, the first cemented lens includes a concave meniscus lens with negative optical power and a convex meniscus lens with positive optical power; the concave meniscus lens is close to the first negative lens, and the convex meniscus lens is far away from the first negative lens.

[0016] In one embodiment, the second lens group includes a double cemented lens group, the double cemented lens group in the second lens group includes a second cemented lens and a third cemented lens, and the second cemented lens is arranged between the first cemented lens and the third cemented lens.

[0017] In one embodiment, the second cemented lens includes two meniscus convex lenses with positive optical power;

[0018] The third cemented lens includes a biconvex lens with positive power and a plano-concave lens with negative power; the biconvex lens is close to the second cemented lens, and the plano-concave lens is far away from the second cemented lens.

[0019] In one embodiment, the first positive lens includes a biconvex lens with positive optical power, the third lens group includes a double cemented lens group, the double cemented lens group in the third lens group includes a fourth cemented lens, and the fourth cemented lens is arranged between the first positive lens and the rear fixed group.

[0020] In one embodiment, the fourth cemented lens includes a biconvex lens with positive optical power and a biconcave lens with negative optical power; the biconvex lens is close to the first positive lens, and the biconcave lens is far away from the first positive lens.

[0021] In one embodiment, the second negative lens includes a meniscus concave lens with negative optical power, the fourth lens group includes a double cemented lens group, the double cemented lens group in the fourth lens group includes a fifth cemented lens, and the fifth cemented lens is arranged between the fourth cemented lens and the second negative lens.

[0022] In one embodiment, the fifth cemented lens includes a concave meniscus lens with negative optical power and a convex meniscus lens with positive optical power; the concave meniscus lens is close to the fourth cemented lens, and the convex meniscus lens is far away from the fourth cemented lens.

[0023] In one embodiment, the optical imaging lens assembly further includes a beam splitter lens, and the beam splitter lens includes a prism or a dichroic mirror;

[0024] The second negative lens is arranged between the fifth cemented lens and the beam splitting lens.

[0025] In one embodiment, the optical imaging lens assembly further includes at least one protective sheet among a first protective sheet, a second protective sheet, a third protective sheet, and a fourth protective sheet;

[0026] The first negative lens is disposed between the first protective sheet and the first cemented lens;

[0027] The second protective sheet is arranged between the second negative lens and the beam splitting lens;

[0028] The third protection sheet is arranged between the second protection sheet and the light splitting lens;

[0029] The light splitting lens is arranged between the third protection sheet and the fourth protection sheet.

[0030] In one embodiment, the first focal length f1 of the front fixed group satisfies -50 mm ≤ f1 ≤ 0 mm, the second focal length f2 of the zoom group satisfies 0 mm ≤ f2 ≤ 50 mm, the third focal length f3 of the compensation group satisfies 50 mm ≤ f3 ≤ 100 mm, and the fourth focal length f4 of the rear fixed group satisfies 100 mm ≤ f4 ≤ 200 mm.

[0031] In one embodiment, -50≤f2 / f1≤0, -25≤f3 / f1≤0, and -10≤f4 / f1≤0.

[0032] In a second aspect, the present application provides a coupler, which includes a detector and any one of the above-mentioned optical imaging lens groups.

[0033] In a third aspect, the present application provides an endoscope comprising the above-mentioned coupler.

[0034] The above-mentioned optical imaging lens group, coupler and endoscope, the optical imaging lens group includes a front fixed group and a zoom group arranged along the optical axis direction, and the zoom group is used to change the focal length of the optical imaging lens group when moving along the optical axis direction. Since the front fixed group includes a first lens group and a first negative lens, and the zoom group includes a second lens group, and the first lens group and the second lens group include a double separated lens group and / or a double cemented lens group, the first negative lens can be used to eliminate astigmatism and field curvature, and the double separated lens group and / or the double cemented lens group in the first lens group and the second lens group 1021 can reduce chromatic aberration and spherical aberration, which is beneficial to the imaging of the optical imaging lens group to improve the imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the structure of an optical imaging lens assembly in an embodiment of the present application;

[0036] Figure 2 This is a schematic structural diagram of another optical imaging lens assembly in an embodiment of the present application;

[0037] Figure 3This is a schematic structural diagram of another optical imaging lens assembly in an embodiment of the present application;

[0038] Figure 4 This is a schematic structural diagram of a front fixing group in an embodiment of the present application;

[0039] Figure 5 This is a schematic diagram of the structure of a zoom group in an embodiment of the present application;

[0040] Figure 6 This is a schematic diagram of the structure of a compensation group in an embodiment of the present application;

[0041] Figure 7 This is a schematic structural diagram of a rear fixing group in an embodiment of the present application;

[0042] Figure 8 This is a schematic structural diagram of another optical imaging lens assembly in an embodiment of the present application;

[0043] Fig. 9 This is a schematic diagram of the structure of a coupler in an embodiment of the present application;

[0044] Fig.10 This is a schematic diagram of the structure of an endoscope in an embodiment of the present application;

[0045] Fig.11 This is a schematic diagram of an MTF curve in an embodiment of the present application;

[0046] Fig.12 This is an aberration diagram in an embodiment of the present application;

[0047] Fig.13 This is an image quality evaluation diagram in an embodiment of the present application;

[0048] Fig.14 This is another image quality evaluation diagram in the embodiment of the present application;

[0049] Fig.15 This is another image quality evaluation diagram in the embodiment of the present application.

[0050] Description of reference numerals:

[0051] 100-optical imaging lens group, 101-front fixed group, 1011-first negative lens, 1012-first lens group, 102-zoom group, 1021-second lens group, 201-compensation group, 2011-first positive lens, 2012-third lens group, 301-rear fixed group, 3011-fourth lens group, 3012-second negative lens, 401-first cemented lens, 4011-meniscus concave lens, 4012-meniscus convex lens, 501-second cemented lens, 5011-meniscus convex lens, 5012-second cemented lens 012-meniscus convex lens, 502-third cemented lens, 5021-double convex lens, 5022-plano-concave lens, 601-fourth cemented lens, 6011-double convex lens, 6012-double concave lens, 701-fifth cemented lens, 7011-meniscus concave lens, 7012-meniscus convex lens, 801-beam splitter lens, 802-first protective plate, 803-second protective plate, 804-third protective plate, 805-fourth protective plate, 900-coupler, 901-detector, 1000-endoscope. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0053] Figure 1 FIG. 1 is a schematic diagram of the structure of an optical imaging lens assembly according to an embodiment of the present application. Figure 1 As shown, the optical imaging lens assembly 100 includes a front fixed group 101 and a zoom group 102 arranged along the optical axis direction. The optical axis direction can be understood as the propagation direction of light. Figure 1 For example, light enters the optical imaging lens group from left to right, that is, light enters from the front fixed group 101 to the zoom group 102 .

[0054] The front fixed group 101 includes a first negative lens 1011 and a first lens group 1012, and the zoom group 102 includes a second lens group 1021. The first lens group 1012 and the second lens group 1021 include a double-separated lens group and / or a double-cemented lens group. Exemplarily, the first lens group 1012 may include at least one double-separated lens, may also include at least one double-cemented lens, and may also include at least one double-separated lens and at least one double-cemented lens, and the second lens group 1021 is the same.

[0055] It should be noted that Figure 1 Taking the example of first disposing the first negative lens 1011 and then disposing the first lens group 1012 along the optical axis, in some embodiments, the first lens group 1012 may be first disposed along the optical axis and then the first negative lens 1011, which is not limited in this embodiment.

[0056] The first negative lens 1011 is a lens with negative optical power, which can be used to eliminate astigmatism and field curvature. The first lens group 1012 and the second lens group 1021 include double separated lens groups and / or double cemented lens groups, so they can reduce chromatic aberration and spherical aberration.

[0057] Exemplarily, the first negative lens 1011 may be a double concave lens, the second lens group 1021 may be a double separated lens group consisting of a meniscus convex lens and a meniscus concave lens, and the third lens group 2012 may be a double separated lens group consisting of a double convex lens and a plano-concave lens.

[0058] Furthermore, the zoom group 102 can change the focal length of the optical imaging lens assembly 100 when moving along the optical axis. In other words, by moving the zoom group 102 and changing the distance between the zoom group 102 and the front fixed group 101, the optical imaging lens assembly 100 with zoom can be realized.

[0059] In other words, the zoom group 102 can change the magnification of the optical imaging lens group 100 during the movement, and the magnification is positively correlated with the distance between the zoom group 102 and the front fixed group 101 .

[0060] The optical imaging lens assembly 100 provided in this embodiment includes a front fixed group 101 and a zoom group 102 arranged along the optical axis direction, and the zoom group 102 is used to change the focal length of the optical imaging lens assembly 100 when moving along the optical axis direction. Since the front fixed group 101 includes a first lens group 1012 and a first negative lens 1011, and the zoom group 102 includes a second lens group 1021, and the first lens group 1012 and the second lens group 1021 include a double separated lens group and / or a double cemented lens group, the first negative lens 1011 can be used to eliminate astigmatism and field curvature, and the double separated lens group and / or the double cemented lens group in the first lens group 1012 and the second lens group 1021 can be used to reduce chromatic aberration and spherical aberration, thereby facilitating the imaging of the optical imaging lens assembly 100 to improve the imaging quality.

[0061] Figure 2 FIG. 1 is a schematic diagram of the structure of another optical imaging lens assembly in an embodiment of the present application. Figure 2 As shown, in one embodiment, optionally, the optical imaging lens assembly 100 further includes a compensation group 201, and the zoom group 102 is disposed between the front fixed group 101 and the compensation group 201. That is, the front fixed group 101, the zoom group 102 and the compensation group 201 are sequentially arranged along the optical axis direction.

[0062] The compensation group 201 includes a first positive lens 2011 and a third lens group 2012, and the third lens group 2012 includes a double-separated lens group and / or a double-cemented lens group. It should be noted that: Figure 2Taking the example of first disposing the first positive lens 2011 and then disposing the third lens group 2012 along the optical axis, in some embodiments, the third lens group 2012 may be first disposed along the optical axis and then the first positive lens 2011, which is not limited in this embodiment.

[0063] The first positive lens 2011 refers to a lens with positive optical power. The first positive lens 2011 generates negative spherical aberration, and the first negative lens 1011 generates positive spherical aberration. Therefore, the first positive lens 2011 and the first negative lens 1011 can be combined to further eliminate astigmatism and field curvature.

[0064] Exemplarily, the first positive lens 2011 may be a biconvex lens, and the third lens group 2012 may be a double-separated lens group consisting of a biconvex lens and a biconcave lens.

[0065] Furthermore, the compensation group 201 can be linked with the zoom group 102 to change the focal length of the optical imaging lens assembly 100 .

[0066] Compensation methods usually include optical compensation or mechanical compensation. Among them, the optical compensation method can achieve the purpose of zooming by moving one or two groups of lenses in the same direction and at the same speed. However, since it can only compensate for a few discrete image positions, obvious image drift will occur when the zoom is large. The mechanical compensation method uses a cam mechanism to drive multiple lenses to move at non-uniform speeds at the same time, which can keep the image plane stable and the image quality good during the zoom process. Therefore, the mechanical compensation method is widely used in zoom optical imaging systems.

[0067] Therefore, in this embodiment, the compensation group 201 adopts a mechanical compensation method. The front fixed group 101 does not move to ensure the focus accuracy. When the zoom group 102 moves linearly along the optical axis, the focal length and image plane position of the optical imaging lens group 100 also change. In order to ensure the stability of the image plane, the compensation group 201 moves according to a certain cam curve to compensate for the image plane position. In other words, the distance between the front fixed group 101 and the zoom group 102, and the distance between the zoom group 102 and the compensation group 201 meet the preset cam curve.

[0068] Furthermore, the compensation group 201 may be a positive group compensation zoom system or a negative group compensation zoom system. The positive group compensation zoom system refers to a system in which the total optical power of the compensation group 201 is positive, and the negative group compensation zoom system refers to a system in which the total optical power of the compensation group 201 is negative. In one embodiment, optionally, the compensation group 201 may be a positive group compensation zoom system.

[0069] The optical imaging lens assembly 100 of this embodiment further includes a compensation group 201, and the zoom group 102 is disposed between the front fixed group 101 and the compensation group 201. Since the compensation group 201 includes the third lens group 2012 and the first positive lens 2011, and the third lens group 2012 includes a double-separated lens group and / or a double-cemented lens group, the first positive lens 2011 further eliminates astigmatism and field curvature after being combined with the first negative lens 1011, and the double-separated lens group and / or the double-cemented lens group in the third lens group 2012 further reduces chromatic aberration and spherical aberration. In addition, since the compensation group 201 can be linked with the zoom group 102 to change the focal length of the optical imaging lens assembly 100, the zoom accuracy of the optical imaging lens assembly 100 is improved.

[0070] Figure 3 FIG. 1 is a schematic diagram of the structure of another optical imaging lens assembly in an embodiment of the present application. Figure 3 As shown, in one embodiment, optionally, the optical imaging lens assembly 100 further includes a rear fixed group 301, and the compensation group 201 is disposed between the zoom group 102 and the rear fixed group 301. That is, the front fixed group 101, the zoom group 102, the compensation group 201 and the rear fixed group 301 are sequentially arranged along the optical axis direction.

[0071] It can be understood that during the zooming process of the optical imaging lens assembly 100, the front fixed group 101 and the rear fixed group 301 are both stationary to ensure focusing accuracy.

[0072] The rear fixed group 301 includes a fourth lens group 3011 and a second negative lens 3012, and the fourth lens group 3011 includes a double separated lens group and / or a double cemented lens group.

[0073] Exemplarily, the second negative lens 3012 may be a meniscus concave lens, and the fourth lens group 3011 may be a double-separated lens group consisting of a meniscus concave lens and a meniscus convex lens.

[0074] The optical imaging lens assembly 100 of this embodiment further includes a rear fixed group 301, and the compensation group 201 is disposed between the zoom group 102 and the rear fixed group 301. Since the rear fixed group 301 includes a fourth lens group 3011 and a second negative lens 3012, and the fourth lens group 3011 includes a double-separated lens group and / or a double-cemented lens group, the rear fixed group 301 can further eliminate astigmatism and field curvature, and reduce chromatic aberration and spherical aberration. In addition, the rear fixed group 301 can further improve the zoom accuracy.

[0075] Figure 4 Schematic diagram of the structure of a front fixing group in an embodiment of the present application, such as Figure 4As shown, in one embodiment, optionally, the first negative lens 1011 includes a biconcave lens with negative optical power, the first lens group 1012 includes a double cemented lens group, and the double cemented lens group in the first lens group 1012 includes a first cemented lens 401. The first cemented lens 401 is disposed between the first negative lens 1011 and the zoom group 102.

[0076] In other words, in the front fixed group 101, the first negative lens 1011 and the first cemented lens 401 can be arranged in sequence along the optical axis direction. The first negative lens 1011 is implemented by a double concave lens with negative optical power.

[0077] In this embodiment, since the first negative lens 1011 includes a biconcave lens with negative optical power, and the double cemented lens group in the first lens group 1012 includes the first cemented lens 401, the first negative lens 1011 and the first cemented lens 401 can be used to eliminate astigmatism and field curvature, and reduce chromatic aberration and spherical aberration.

[0078] Please continue to refer to Figure 4 In one embodiment, optionally, the first cemented lens 401 includes a meniscus concave lens 4011 with negative optical power and a meniscus convex lens 4012 with positive optical power. The meniscus concave lens 4011 is close to the first negative lens 1011, and the meniscus convex lens 4012 is far away from the first negative lens 1011.

[0079] That is, in the front fixed group 101, the first negative lens 1011, the first cemented lens 401 composed of a meniscus concave lens 4011 and a meniscus convex lens 4012 can be sequentially arranged along the optical axis. The first negative lens 1011 is realized by a double concave lens with negative optical power.

[0080] In this embodiment, since the first cemented lens 401 includes a concave meniscus lens 4011 with negative optical power and a convex meniscus lens 4012 with positive optical power, the first lens group 1012 is arranged in the front fixed group 101 to reduce spherical aberration and chromatic aberration.

[0081] Figure 5 Schematic diagram of the structure of a zoom group in the embodiment of the present application. Figure 5 As shown, in one embodiment, optionally, the second lens group 1021 includes a double cemented lens group, the double cemented lens group in the second lens group 1021 includes a second cemented lens 501 and a second cemented lens 502, and the second cemented lens 501 is arranged between the first cemented lens 401 and the second cemented lens 502.

[0082] That is, the second cemented lens 501 and the second cemented lens 502 can be arranged in sequence along the optical axis in the zoom group 102. Thus, by providing a plurality of double cemented lenses in the zoom group 102, chromatic aberration and spherical aberration can be further reduced, and the zoom accuracy can be improved.

[0083] Please continue to refer to Figure 5 In one embodiment, optionally, the second cemented lens 501 includes two meniscus convex lenses 5011 and a meniscus convex lens 5012 with positive power. The second cemented lens 502 includes a biconvex lens 5021 with positive power and a plano-concave lens 5022 with negative power, wherein the biconvex lens 5021 is close to the second cemented lens 501, and the plano-concave lens 5022 is far away from the second cemented lens 501.

[0084] That is, in the zoom group 102, the second cemented lens 501 composed of the meniscus convex lens 5011 and the meniscus convex lens 5012 and the third cemented lens 502 composed of the biconvex lens 5021 and the plano-concave lens 5022 can be arranged in sequence along the optical axis. In this way, the second lens group 1021 is arranged in the zoom group 102.

[0085] Figure 6 Schematic diagram of the structure of a compensation group in the embodiment of the present application. Figure 6 As shown, in one embodiment, optionally, the first positive lens 2011 includes a biconvex lens with positive optical power. The third lens group 2012 includes a double cemented lens group, and the double cemented lens group in the third lens group 2012 includes a fourth cemented lens 601. The fourth cemented lens 601 is arranged between the first positive lens 2011 and the rear fixed group 301.

[0086] That is, the first positive lens 2011 and the fourth cemented lens 601 may be sequentially arranged along the optical axis in the compensation group 201. The first positive lens 2011 is implemented by a biconvex lens with positive optical power.

[0087] Please continue to refer to Figure 6 In one embodiment, optionally, the fourth cemented lens 601 includes a biconvex lens 6011 with positive optical power and a biconcave lens 6012 with negative optical power; the biconvex lens 6011 is close to the first positive lens 2011, and the biconcave lens 6012 is far away from the first positive lens 2011.

[0088] That is, in the compensation group 201, the first positive lens 2011 and the fourth cemented lens 601 composed of a biconvex lens 6011 and a biconcave lens 6012 can be sequentially arranged along the optical axis. In this way, the compensation group 201 can eliminate astigmatism and field curvature, and reduce chromatic aberration and spherical aberration by using the first positive lens 2011 and the fourth cemented lens 601.

[0089] Figure 7 Schematic diagram of the structure of a rear fixing group in the embodiment of the present application. Figure 7 As shown, in one embodiment, optionally, the fourth lens group 3011 includes a doublet lens group, the doublet lens group in the fourth lens group 3011 includes a fifth cemented lens 701, and the fifth cemented lens 701 is arranged between the fourth cemented lens 601 and the second negative lens 3012. The second negative lens 3012 includes a meniscus concave lens with negative optical power.

[0090] That is to say, in the rear fixed group 301, the fifth cemented lens 701 and the second negative lens 3012 can be arranged in sequence along the optical axis direction, and the second negative lens 3012 is realized by a meniscus concave lens with negative optical power.

[0091] Please continue to refer to Figure 7 The fifth cemented lens 701 includes a meniscus concave lens 7011 with negative optical power and a meniscus convex lens 7012 with positive optical power; the meniscus concave lens 7011 is close to the fourth cemented lens 601, and the meniscus convex lens 7012 is far away from the fourth cemented lens 601.

[0092] That is to say, in the rear fixed group 301, the fifth cemented lens 701 composed of the meniscus concave lens 7011 and the meniscus convex lens 7012 and the second negative lens 3012 can be arranged in sequence along the optical axis direction. In this way, the fourth lens group 3011 and the second negative lens 3012 are arranged in the compensation group 201, so as to eliminate astigmatism and field curvature by using the second negative lens 3012, and reduce chromatic aberration and spherical aberration by using the fourth lens group 3011.

[0093] Figure 8 FIG. 1 is a schematic diagram of the structure of another optical imaging lens assembly in an embodiment of the present application. Figure 8 As shown, in one embodiment, optionally, the optical imaging lens assembly 100 further includes a beam splitter lens 801 , and the second negative lens 3012 is disposed between the fifth cemented lens 701 and the beam splitter lens 801 .

[0094] The beam splitter lens 801 is used to separate light beams of different wavelength bands, for example, to distinguish between visible light and infrared light. The beam splitter lens 801 includes a prism or a dichroic mirror.

[0095] In this embodiment, since the beam splitter lens 801 is provided, the optical imaging lens assembly 100 can be used in multiple bands. Furthermore, since the prism or the dichroic mirror is a parallel flat plate, the influence on the aberration is small, which is beneficial to imaging.

[0096] Please continue to refer to Figure 8In one embodiment, optionally, the optical imaging lens assembly 100 further includes at least one protective sheet among a first protective sheet 802 , a second protective sheet 803 , a third protective sheet 804 and a fourth protective sheet 805 .

[0097] The first negative lens 1011 is disposed between the first protective sheet 802 and the first cemented lens 401. The second protective sheet 803 is disposed between the second negative lens 3012 and the light splitting lens 801. The third protective sheet 804 is disposed between the second protective sheet 803 and the light splitting lens 801. The light splitting lens 801 is disposed between the third protective sheet 804 and the fourth protective sheet 805.

[0098] Since at least one protective sheet is provided in the optical imaging lens assembly 100 , the stability of the optical imaging lens assembly 100 is improved.

[0099] Please refer to Figure 8 (a)~ Figure 8 (d) The front fixed lens group 101 and the rear fixed group 301 can remain stationary, and the zoom group 102 and the compensation group 201 in the dotted frame are linked together along the optical axis to achieve a zoom effect.

[0100] In one embodiment, optionally, the first focal length f1 of the front fixed group 101 satisfies -50 mm ≤ f1 ≤ 0 mm, the second focal length f2 of the zoom group 102 satisfies 0 mm ≤ f2 ≤ 50 mm, the third focal length f3 of the compensation group 201 satisfies 50 mm ≤ f3 ≤ 100 mm, and the fourth focal length f4 of the rear fixed group 301 satisfies 100 mm ≤ f4 ≤ 200 mm.

[0101] In one embodiment, optionally, -50≤f2 / f1≤0, -25≤f3 / f1≤0, and -10≤f4 / f1≤0.

[0102] Since the focal lengths of the front fixed group 101 , the variable power group 102 , the compensation group 201 and the rear fixed group 301 in the optical imaging lens assembly 100 can meet the above requirements, the optical imaging lens assembly 100 of this embodiment is more conducive to imaging.

[0103] In summary, the optical imaging lens group usually adopts a wide band of 460nm to 860nm. The wider the band, the greater the chromatic aberration in the optical system, and the spherical aberration has an important influence on the design of the imaging optical system. Since the positive lens produces negative spherical aberration and the negative lens produces positive spherical aberration, the spherical aberration can be corrected by combining the positive and negative lenses. Therefore, in this embodiment, the optical imaging lens group 100 adopts more double-cemented lenses to form an aplanatic optical group to reduce chromatic aberration and spherical aberration. The first negative lens, the first positive lens, and the second negative lens are used as meniscus lenses mainly to eliminate astigmatism and field curvature.

[0104] Fig. 9Schematic diagram of the structure of a coupler in an embodiment of the present application. Fig. 9 As shown, in one embodiment, a coupler 900 is further provided. The coupler 900 includes any one of the above-mentioned optical imaging lens assembly 100 and a detector 901. It can be understood that the detector 901 is arranged behind the optical imaging lens assembly 100 along the optical axis direction.

[0105] by Fig. 9 For example, the light passes through the first protective film 802, the first negative lens 1011, the first cemented lens 401, the second cemented lens 501, the third cemented lens 502, the first positive lens 2011, the fourth cemented lens 601, the fifth cemented lens 701, the second negative lens 3012, the second protective film 803, the third protective film 804, the beam splitter lens 801, and the fourth protective film 805, and finally performs high-resolution imaging on the target surface of the detector 901. It can be understood that Fig. 9 The coupler 900 shown is a zoom coupler.

[0106] It can be seen that the above-mentioned couplers all use spherical mirrors, and the entrance pupil is located on the first surface, which is conducive to coupling with the exit pupil at the eyepiece of the hard optical mirror.

[0107] Fig.10 Schematic diagram of the structure of an endoscope in an embodiment of the present application, such as Fig.10 As shown, in one embodiment, an endoscope 1000 is also provided, and the endoscope 1000 includes the above-mentioned coupler 900.

[0108] In some embodiments, the endoscope 1000 may further include at least one of a light source component, an image processing component, a control mechanism, and a display component.

[0109] In this way, the optical imaging lens group 100 can be applied to the zoom optical system of a medical rigid tube endoscope to complete medical endoscope detection, and by utilizing the linkage of the magnification group 102 and the compensation group 201, the focal length can be adaptively adjusted according to the distance of the endoscope from the biological tissue, so as to magnify and reduce, and zoom in and out, the lesion area of ​​the biological tissue.

[0110] For example, in one embodiment, the focal length of the optical imaging lens group 100 varies from 16 to 34 mm (millimeter), and a detector 901 with a 4K resolution of 1 / 1.8 inches is connected to form a 4K zoom coupler. For example, the 4K zoom coupler can achieve a high resolution of 7.94 million pixels (3680×2160), with a maximum distortion of less than 1.85%, and a field of view angle given by the maximum field of view angle at the eyepiece of the measured 4K optical scope (hard tube endoscope). The field of view half-angle varies from 0 to 8.5° (degrees), and the relative illumination is above 86%, which is a high relative illumination. Among them, the ratio of the illumination at the edge of the field of view to the illumination at the center is expressed as relative illumination, and the higher the relative illumination, the brighter the edge. In general, observation can be made when the relative illumination reaches 50% or more.

[0111] In addition, since the 4K zoom coupler has a spectroscopic lens, it can perform near-infrared imaging and visible light imaging simultaneously using a dual-detector camera, and has a certain universality.

[0112] It can be seen that the above-mentioned 4K zoom coupler has the advantages of high resolution, wide-band imaging, wide field of view imaging, and small distortion, and has a wide range of application scenarios, especially in the field of wearable medical devices. Taking the above-mentioned 4K zoom coupler used in endoscopes as an example, it can present high-resolution images, which is convenient for doctors to observe and diagnose, thereby meeting the urgent needs of surgical medical use.

[0113] Fig.11 Schematic diagram of an MTF curve in the embodiment of the present application. Since the prism or dichroic mirror is a parallel plate, the influence on the aberration is very small, so only the influence of the prism on the single path - the transmission path is analyzed. Under this condition, the MTF curve between 0 and 250 lp / mm (line pairs / mm) at the short-focus 16mm structure is as follows Fig.11 shown.

[0114] At 250lp / mm, the MTF (Modulation Transfer Function) value is greater than 0.1. Fig.11 The MTF curves corresponding to the meridian and sagittal planes at four different positions of the central field of view, 2.5°, 5.0°, and 8.5° (edge ​​field of view) at frequencies of 0 to 250 lp / mm are given, and the MTF curve under diffraction limit conditions is given for comparison. The pixel of a 1 / 1.8-inch chip with a resolution of 3840*2160 is 2 microns, corresponding to a Nyquist frequency of 250 lp / mm. Under this line pair, the MTF value > 0.1 meets the resolution requirements of the chip.

[0115] Fig.12 is an aberration diagram in the embodiment of the present application, Fig.12 (a)~ Fig.12(f) shows the aberration diagrams of the optical imaging lens group at a focal length of 16 mm, the relative illumination, the field curvature, the distortion, the position chromatic aberration, and the magnification chromatic aberration. Fig.12 As shown, the root mean square (RMS) radii of the diffuse spots are all within the radius of the Airy disk, the relative illumination is greater than 99%, the meridian field curvature is within 0.0116mm, the sagittal field curvature is within 0.0017mm, the distortion is less than 1.3% at full field of view, the position chromatic aberration is within 0.019mm, and the maximum magnification chromatic aberration is 2.27 microns, which is smaller than the Airy disk diameter.

[0116] Fig.13 is an image quality evaluation diagram in the embodiment of the present application, Fig.13 (a)~ Fig.13 (g) shows the image quality evaluation diagrams of the MTF diagram, point diagram, relative illumination, field curvature, distortion, position chromatic aberration, and magnification chromatic aberration of the optical imaging lens group at a focal length of 24.29 mm.

[0117] like Fig.13 As shown, the MTF value is greater than 0.33 at 125lp / mm. Fig.13 The MTF graph shows the MTF curves corresponding to the meridian and sagittal planes at four different positions of the central field of view, 2.5°, 5.0°, and 8.5° (edge ​​field of view) at frequencies of 0-125lp / mm, and the MTF curve under diffraction limit conditions is given for comparison. It can be seen that the RMS radius of the diffuse spot is all within the radius of the Airy disk, the relative illumination is greater than 96%, the meridian field curvature is less than 0.0329mm, the sagittal field curvature is less than 0.0155mm, the distortion is less than 0.29% in the full field of view, the position chromatic aberration is less than 0.035mm, and the maximum magnification chromatic aberration is 1.08 microns, which is less than the Airy disk diameter.

[0118] Fig.14 This is another image quality evaluation diagram in the embodiment of the present application. Fig.14 (a)~ Fig.13 (g) shows the MTF diagram, point diagram, relative illumination, field curvature, distortion, position chromatic aberration, and image quality evaluation diagrams of the optical imaging lens group at a focal length of 32.00 mm in sequence.

[0119] like Fig.14 As shown, the MTF value is greater than 0.16 at 125lp / mm. Fig.14The MTF graph shows the MTF curves corresponding to the meridian and sagittal planes at four different positions of the central field of view, 2.5°, 5.0°, and 8.5° (edge ​​field of view) at frequencies of 0-125lp / mm, and the MTF curve under diffraction limit conditions is given for comparison. The RMS radius of the diffuse spot is all within the radius of the Airy disk, the relative illumination is greater than 89%, the meridian field curvature is less than 0.0589mm, the sagittal field curvature is less than 0.0258mm, the distortion is less than 1.4% at full field of view, the position chromatic aberration is less than 0.054mm, and the maximum magnification chromatic aberration is 0.98 microns, which is less than the Airy disk diameter.

[0120] Fig.15 This is another image quality evaluation diagram in the embodiment of the present application. Fig.14 (a)~ Fig.13 (g) shows the image quality evaluation diagrams of the MTF diagram, point diagram, relative illumination, field curvature, distortion, position chromatic aberration, and magnification chromatic aberration of the optical imaging lens group at a focal length of 34.00 mm.

[0121] like Fig.15 As shown, the MTF value is greater than 0.11 at 125lp / mm. Fig.15 The MTF graph shows the MTF curves corresponding to the meridian and sagittal planes at four different positions of the central field of view, 2.5°, 5.0°, and 8.5° (edge ​​field of view) at frequencies of 0-125lp / mm, and the MTF curve under diffraction limit conditions is given for comparison. The RMS radius of the diffuse spot is all within the radius of the Airy disk, the relative illumination is greater than 86%, the meridian field curvature is less than 0.0934mm, the sagittal field curvature is less than 0.0281mm, the distortion is less than 1.85% in the full field of view, the position chromatic aberration is less than 0.059mm, and the maximum magnification chromatic aberration is 1.24 microns, which is less than the Airy disk diameter.

[0122] In summary, the optical imaging lens set, coupler and endoscope provided in this embodiment have high resolution, small distortion, MTF modulation function close to the diffraction limit, and RMS radius of diffuse spots of different field of view imaging are all within the radius of Airy disk. It can also clearly image in the wide band range of 460-860nm, and with the addition of a beam splitter lens, it can be applied to visible light imaging of endoscopes and ICG (indocyanine green) fluorescence imaging of endoscopes, which is helpful for the research and development and production of optical imaging lens sets in white light + fluorescence mode.

[0123] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0124] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. An optical imaging lens assembly, characterized in that: The optical imaging lens group includes a front fixed group and a variable magnification group arranged along the optical axis direction; The front fixed group includes a first lens group and a first negative lens, and the variable power group includes a second lens group; the first lens group and the second lens group include a double separated lens group and / or a double cemented lens group; The variable magnification group is used to change the focal length of the optical imaging lens group while moving along the optical axis direction.

2. The optical imaging lens assembly according to claim 1, characterized in that: The optical imaging lens assembly further includes a compensation group, and the variable magnification group is arranged between the front fixed group and the compensation group; The compensation group includes a third lens group and a first positive lens, and the third lens group includes a double separated lens group and / or a double cemented lens group; The compensation group is used to work in conjunction with the zoom group to change the focal length of the optical imaging lens group.

3. The optical imaging lens assembly according to claim 2, characterized in that: The optical imaging lens assembly further includes a rear fixing group, and the compensation group is arranged between the variable magnification group and the rear fixing group; The rear fixed group includes a fourth lens group and a second negative lens, and the fourth lens group includes a double separated lens group and / or a double cemented lens group.

4. The optical imaging lens assembly according to any one of claims 1 to 3, characterized in that: The first negative lens includes a biconcave lens with negative optical power, the first lens group includes a double cemented lens group, the double cemented lens group in the first lens group includes a first cemented lens, and the first cemented lens is arranged between the first negative lens and the variable power group.

5. The optical imaging lens assembly according to claim 4, characterized in that: The first cemented lens includes a concave meniscus lens with negative optical power and a convex meniscus lens with positive optical power; the concave meniscus lens is close to the first negative lens, and the convex meniscus lens is far away from the first negative lens.

6. The optical imaging lens assembly according to any one of claims 1 to 3, characterized in that: The second lens group includes a double cemented lens group, the double cemented lens group in the second lens group includes a second cemented lens and a third cemented lens, and the second cemented lens is arranged between the first cemented lens and the third cemented lens.

7. The optical imaging lens assembly according to claim 6, characterized in that: The second cemented lens comprises two meniscus convex lenses with positive optical power; The third cemented lens includes a biconvex lens with positive power and a plano-concave lens with negative power; the biconvex lens is close to the second cemented lens, and the plano-concave lens is far away from the second cemented lens.

8. The optical imaging lens assembly according to claim 3, characterized in that: The first positive lens includes a biconvex lens with positive optical power, the third lens group includes a double cemented lens group, the double cemented lens group in the third lens group includes a fourth cemented lens, and the fourth cemented lens is arranged between the first positive lens and the rear fixed group.

9. The optical imaging lens assembly according to claim 8, characterized in that: The fourth cemented lens includes a biconvex lens with positive power and a biconcave lens with negative power; the biconvex lens is close to the first positive lens, and the biconcave lens is far away from the first positive lens.

10. The optical imaging lens assembly according to claim 3, characterized in that: The second negative lens includes a meniscus concave lens with negative optical power, the fourth lens group includes a double cemented lens group, the double cemented lens group in the fourth lens group includes a fifth cemented lens, and the fifth cemented lens is arranged between the fourth cemented lens and the second negative lens.

11. The optical imaging lens assembly according to claim 10, characterized in that: The fifth cemented lens includes a concave meniscus lens with negative optical power and a convex meniscus lens with positive optical power; the concave meniscus lens is close to the fourth cemented lens, and the convex meniscus lens is far away from the fourth cemented lens.

12. The optical imaging lens assembly according to claim 11, characterized in that: The optical imaging lens assembly further includes a beam splitter lens, and the beam splitter lens includes a prism or a dichroic mirror; The second negative lens is disposed between the fifth cemented lens and the beam splitter lens.

13. The optical imaging lens assembly according to claim 12, characterized in that: The optical imaging lens assembly further includes at least one protective sheet among a first protective sheet, a second protective sheet, a third protective sheet and a fourth protective sheet; The first negative lens is disposed between the first protective sheet and the first cemented lens; The second protective sheet is disposed between the second negative lens and the beam splitting lens; The third protective sheet is disposed between the second protective sheet and the light splitting lens; The beam splitter lens is disposed between the third protection sheet and the fourth protection sheet.

14. The optical imaging lens assembly according to claim 3, characterized in that: The first focal length f1 of the front fixed group satisfies -50 mm ≤ f1 ≤ 0 mm, the second focal length f2 of the zoom group satisfies 0 mm ≤ f2 ≤ 50 mm, the third focal length f3 of the compensation group satisfies 50 mm ≤ f3 ≤ 100 mm, and the fourth focal length f4 of the rear fixed group satisfies 100 mm ≤ f4 ≤ 200 mm.

15. The optical imaging lens assembly according to claim 14, characterized in that: -50≤f2 / f1≤0, -25≤f3 / f1≤0, -10≤f4 / f1≤0.

16. A coupler, characterized in that: The coupler comprises a detector and an optical imaging lens assembly as described in any one of claims 1-15.

17. An endoscope, characterized in that: The endoscope includes the coupler of claim 16.

Images