Liquid focusing lens

Abstract

The utility model discloses a liquid focusing lens, including first lens group, second lens group and third lens group who set gradually from object side to image side, and second lens group contains liquid lens, changes the focal length of liquid lens through the curvature of liquid surface and makes, finally reach the purpose of focusing. The utility model discloses a liquid focusing lens, satisfy small size while having focusing speed fast, efficiency high, precision high, resolving power high, satisfy equipment miniaturization use demand etc. multiple advantages, and liquid lens can replace, can use the liquid lens of different manufacturers on market, more general; Liquid focusing lens is suitable for wide range of object distance, can be used for different object distance, and the object distance range satisfies: 80mm~infinity.

Description

Technical Field

[0001] This utility model belongs to the field of optical lens technology, and specifically relates to a liquid focusing lens. Background Technology

[0002] Currently, most industrial equipment is equipped with traditional industrial focusing lenses. The characteristic of these lenses is that the impact of changes in object distance can only be compensated for by moving the lens group, thus maintaining image quality and making it unaffected by changes in object distance. The methods of moving the lens group are roughly divided into two types: manual focusing and motorized focusing. Manual focusing is slow and inefficient, while motorized focusing, although fast, results in a larger overall lens size, which is not conducive to miniaturization.

[0003] With the rapid development of technology, the development of liquid lenses has undergone tremendous changes, and related technologies have moved from the laboratory stage to the mass production and civilian application stage. Compared with traditional industrial focusing lenses, lenses with liquid lenses have advantages such as smaller size and faster focusing speed, which can further miniaturize industrial equipment equipped with optical lenses.

[0004] Based on this, the present invention discloses a liquid focusing lens. Utility Model Content

[0005] To address the technical problems existing in the prior art, the purpose of this utility model is to provide a liquid focusing lens that, while satisfying the requirements of small size, has advantages such as fast focusing speed, high resolution, and meeting the needs of miniaturized equipment.

[0006] To achieve the above objectives and technical effects, the technical solution adopted by this utility model is as follows:

[0007] A liquid focusing lens includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side. The second lens group includes a liquid lens. By changing the curvature of the liquid surface, the focal length of the liquid lens is changed, ultimately achieving the purpose of focusing.

[0008] Furthermore, the first lens group satisfies the following relationship:

[0009] -6 <f1 / f<-2;

[0010] Where f is the focal length of the liquid focusing lens, and f1 is the focal length of the first lens group.

[0011] Furthermore, the first lens group includes a first lens and a second lens arranged sequentially from the object side to the image side, and the first lens and the second lens satisfy the following conditions:

[0012] Nd(G1)≥1.7;

[0013] Nd(G2)≥1.7;

[0014] Wherein, Nd(G1) is the refractive index of the first lens, and Nd(G2) is the refractive index of the second lens.

[0015] Furthermore, the first lens is a meniscus positive lens with its convex surface facing the object plane, and the second lens is a plano-concave negative lens with its concave surface facing the image plane.

[0016] Furthermore, the first lens is a plano-convex positive lens with the convex surface facing the object surface, and the second lens is a biconcave negative lens.

[0017] Furthermore, the liquid lens satisfies the following relationship:

[0018] -0.015 < 1 / fy < 0.025;

[0019] Where fy is the focal length of the liquid lens.

[0020] Furthermore, the liquid lens satisfies the following condition:

[0021] The length of the liquid lens (including the liquid lens itself) is ≥3.5mm.

[0022] Furthermore, the third lens group includes a third lens and a fourth lens arranged sequentially from the object side to the image side. The third lens is a biconvex positive diopter lens, and the fourth lens is a biconcave negative diopter lens.

[0023] The third and fourth lenses satisfy the following conditions:

[0024] Nd(G3)≥1.7;

[0025] Nd(G4)≥1.7;

[0026] Wherein, Nd(G3) is the refractive index of the third lens, and Nd(G4) is the refractive index of the fourth lens.

[0027] Furthermore, the third lens group includes a third lens, a fourth lens, and a fifth lens arranged sequentially from the object side to the image side. The third lens is a biconvex positive diopter lens, and the fourth lens is a biconcave negative diopter lens.

[0028] The third lens, fourth lens, and fifth lens satisfy the following conditions:

[0029] Nd(G3)≥1.7;

[0030] Nd(G4)≥1.7;

[0031] Nd(G5)≥1.8;

[0032] Wherein, Nd(G3) is the refractive index of the third lens, Nd(G4) is the refractive index of the fourth lens, and Nd(G5) is the refractive index of the fifth lens.

[0033] Furthermore, the liquid focusing lens satisfies the following relationship:

[0034] -1 <f4 / f<3;

[0035] Where f is the focal length of the liquid focusing lens, and f4 is the combined focal length of the third, fourth, and fifth lenses.

[0036] Furthermore, the third lens and the fourth lens are not glued together. In this case, the third lens and the fourth lens satisfy the following conditions:

[0037] -20 <f2 / f<5;

[0038] Where f is the focal length of the liquid focusing lens, and f2 is the combined focal length of the third and fourth lenses.

[0039] Furthermore, the third lens and the fourth lens are cemented together to form a first cemented lens group, which satisfies the following relationship:

[0040] -20 <f3 / f<5;

[0041] Where f is the focal length of the liquid focusing lens, and f3 is the focal length of the first cemented lens group.

[0042] Furthermore, the fifth lens is a biconvex positive diopter lens.

[0043] Furthermore, the fifth lens is a plano-convex positive diopter lens, with the convex surface facing the image plane.

[0044] Furthermore, an aperture stop is provided between the second lens group and the third lens.

[0045] Furthermore, the liquid focusing lens has a focal length of f=16mm, an aperture value of FNO=5.6, a half-image height of ≤4.8mm, and a total length of 30mm or less.

[0046] This utility model also discloses a camera instrument including the liquid focusing lens as described above, wherein the camera instrument is any one of a camera, video camera, microscope, telescope, and endoscope.

[0047] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0048] 1) Compared with previous focusing lenses, the liquid focusing lens disclosed in this utility model is smaller in size and suitable for use in miniaturized devices;

[0049] 2) Compared with previous focusing lenses, the liquid focusing lens disclosed in this utility model has higher accuracy and is easier to operate.

[0050] 3) The liquid focusing lens disclosed in this utility model has strong versatility, the liquid lens can be replaced, and liquid lenses produced by different manufacturers on the market can be used.

[0051] 4) Compared with previous focusing lenses, the liquid focusing lens disclosed in this utility model has a faster focusing speed and higher efficiency.

[0052] 5) The liquid focusing lens disclosed in this utility model is suitable for different interface types;

[0053] 6) The liquid focusing lens disclosed in this utility model has a wide range of applicable object distances and can be used for different object distances, with the object distance range satisfying: 80mm~∞. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the liquid focusing lens of Embodiment 1 of this utility model;

[0055] Figure 2 This is a schematic diagram of the MTF of Embodiment 1 of this utility model;

[0056] Figure 3 This is a schematic diagram of the liquid focusing lens of Embodiment 2 of this utility model;

[0057] Figure 4 This is a schematic diagram of the MTF of Embodiment 2 of this utility model. Detailed Implementation

[0058] The present invention will now be described in detail so that its advantages and features can be more easily understood by those skilled in the art, thereby providing a clearer and more definite definition of the scope of protection of the present invention.

[0059] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0060] like Figure 1-4As shown, a liquid focusing lens includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side. The first lens group includes a first lens G1 and a second lens G2, and the second lens group includes a liquid lens L1. By changing the curvature of the liquid surface, the focal length of the liquid lens L1 is changed, ultimately achieving the purpose of focusing.

[0061] In this invention, the focal length of the liquid lens L1 can be changed by altering its refractive index or shape. Alternatively, the focal length can be changed by modifying the operating voltage to alter the properties of the liquid lens L1 itself.

[0062] In this invention, the first lens group satisfies the following relationship:

[0063] -6 <f1 / f<-2;

[0064] Where f is the focal length of the liquid focusing lens, and f1 is the focal length of the first lens group.

[0065] In this invention, an aperture stop STO is provided between the second lens group and the third lens G3.

[0066] In this invention, the first lens G1 and the second lens G2 satisfy the following conditions:

[0067] n(G1)≥1.7;

[0068] n(G2)≥1.7;

[0069] Where n(G1) is the refractive index of the first lens G1, and n(G2) is the refractive index of the second lens G2.

[0070] In some embodiments, the first lens group includes: a first lens G1 being a meniscus positive lens with its convex surface facing the object plane; and a second lens G2 being a plano-concave negative lens with its concave surface facing the image plane.

[0071] In some embodiments, the first lens group includes: a first lens G1 is a plano-convex positive lens with its convex surface facing the object surface; and a second lens G2 is a biconcave negative lens.

[0072] In this invention, the liquid lens L1 satisfies the following conditions:

[0073] The length of the liquid lens (including the liquid lens itself) is ≥3.5mm, and liquid lenses from different manufacturers can be replaced as needed.

[0074] The liquid lens L1 satisfies the following relationship:

[0075] -0.015 < 1 / fy < 0.025;

[0076] Where fy is the focal length of the liquid lens L1, the liquid lens L1 changes its own performance by changing the operating voltage, thereby changing the focal length and ultimately achieving the purpose of focusing.

[0077] In some embodiments, the third lens group includes a third lens G3 and a fourth lens G4 arranged sequentially from the object side to the image side. The third lens G3 is a biconvex positive diopter lens, and the fourth lens G4 is a biconcave negative diopter lens. The third lens G3 and the fourth lens G4 satisfy the following conditions:

[0078] Nd(G3)≥1.7;

[0079] Nd(G4)≥1.7;

[0080] Wherein, Nd(G3) is the refractive index of the third lens G3, and Nd(G4) is the refractive index of the fourth lens G4.

[0081] In some embodiments, the third lens group includes a third lens G3, a fourth lens G4, and a fifth lens G5 arranged sequentially from the object side to the image side. The third lens G3 is a biconvex positive diopter lens, and the fourth lens G4 is a biconcave negative diopter lens, satisfying the following conditions:

[0082] Nd(G3)≥1.7;

[0083] Nd(G4)≥1.7;

[0084] Nd(G5)≥1.8;

[0085] Wherein, Nd(G3) is the refractive index of the third lens G3, Nd(G4) is the refractive index of the fourth lens G4, and Nd(G5) is the refractive index of the fifth lens G5.

[0086] In some embodiments, the third lens G3 and the fourth lens G4 may not be cemented together. In this case, the third lens G3 and the fourth lens G4 satisfy the following conditions:

[0087] -20 <f2 / f<5;

[0088] Where f is the focal length of the liquid focusing lens, and f2 is the combined focal length of the third lens G3 and the fourth lens G4.

[0089] In some embodiments, the third lens G3 and the fourth lens G4 can be cemented together to form a first cemented lens group D1, which satisfies the following relationship:

[0090] -20 <f3 / f<5;

[0091] Where f3 is the focal length of the first cemented lens group D1.

[0092] In some implementations, the liquid focusing lens satisfies the following relationship:

[0093] -1 <f4 / f<3;

[0094] Where f4 is the combined focal length of the third lens G3, the fourth lens G4, and the fifth lens G5.

[0095] In some implementations, the fifth lens G5 is a biconvex positive diopter lens.

[0096] In some embodiments, the fifth lens G5 is a plano-convex positive diopter lens with the convex surface facing the image plane.

[0097] The liquid focusing lens disclosed in this utility model has a focal length of f=16mm, an aperture value of FNO=5.6, a half-image height of ≤4.8mm, and a total length of 30mm or less. The overall length is relatively short, and the size of the entire lens is small.

[0098] This utility model also discloses a camera instrument including the liquid focusing lens as described above, which can be any one of a camera, video camera, microscope, telescope, or endoscope.

[0099] Example 1

[0100] like Figure 1-2 As shown, a liquid focusing lens includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side. The first lens group includes a first lens G1 and a second lens G2 arranged sequentially from the object side to the image side. The second lens group includes a liquid lens L1. The third lens group includes a third lens G3, a fourth lens G4, and a fifth lens G5 arranged sequentially from the object side to the image side. An aperture stop STO is provided between the second lens group and the third lens G3. All lenses are glass spherical surfaces.

[0101] The first lens G1 is a meniscus positive lens with its convex surface facing the object plane; the second lens G2 is a plano-concave negative lens with its concave surface facing the image plane; the third lens G3 is a biconvex positive diopter lens; the fourth lens G4 is a biconcave negative diopter lens; and the fifth lens G5 is a plano-convex positive diopter lens with its convex surface facing the image plane.

[0102] The image side of the fifth lens G5 is equipped with a protective glass IR+CG.

[0103] The first lens group satisfies the following relationship:

[0104] f1 / f = -3.7;

[0105] Where f is the focal length of the liquid focusing lens, and f1 is the focal length of the first lens group.

[0106] The third lens G3 and the fourth lens G4 are cemented together to form the first cemented lens group D1, which satisfies the following relationship:

[0107] f3 / f = -5.22;

[0108] Where f3 is the focal length of the first cemented lens group D1.

[0109] The liquid lens L1 satisfies the following relationship:

[0110] 1 / fy = -0.0006 (at an object distance of 400 mm);

[0111] Where fy is the focal length of the liquid lens L1, the liquid lens L1 changes its own performance by changing the operating voltage, thereby changing the focal length and ultimately achieving the purpose of focusing.

[0112] The liquid focusing lens in this embodiment satisfies the following relationship:

[0113] f4 / f = 0.66;

[0114] Where f4 is the focal length of the combination of the third lens G3, the fourth lens G4, and the fifth lens G5.

[0115] The parameters of the liquid focusing lens in this embodiment are shown in Table 1.

[0116] Table 1

[0117]

[0118] The shape, material, refractive index, and Abbe number parameters of each lens in this embodiment are shown in Table 2.

[0119]

[0120] In Table 2, when the radius of curvature is Infinity, it indicates that the surface is a plane.

[0121] Figure 2 This is a schematic diagram of the MTF in this embodiment. The OTF coefficient corresponding to the spatial frequency of 145LP / mm in the center field of view is above 0.22, and the lens achieves high resolution.

[0122] Example 2

[0123] like Figure 3-4As shown, a liquid focusing lens includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side. The first lens group includes a first lens G1 and a second lens G2 arranged sequentially from the object side to the image side. The second lens group includes a liquid lens L1. The third lens group includes a third lens G3, a fourth lens G4, and a fifth lens G5 arranged sequentially from the object side to the image side. An aperture stop STO is provided between the second lens group and the third lens G3. All lenses are glass spherical surfaces.

[0124] The first lens G1 is a plano-convex positive lens with the convex surface facing the object plane; the second lens G2 is a biconcave negative lens; the third lens G3 is a biconvex positive refractive power lens; the fourth lens G4 is a biconcave negative refractive power lens; and the fifth lens G5 is a biconvex positive refractive power lens.

[0125] The image side of the fifth lens G5 is equipped with a protective glass IR+CG.

[0126] The first lens group satisfies the following relationship:

[0127] f1 / f = -4.4;

[0128] Where f is the focal length of the liquid focusing lens, and f1 is the focal length of the first lens group.

[0129] The third lens G3 and the fourth lens G4 are not cemented together and satisfy the following relationship:

[0130] f² / f = 2.8;

[0131] Where f2 is the combined focal length of the third lens G3 and the fourth lens G4.

[0132] The liquid lens L1 satisfies the following relationship:

[0133] 1 / fy = -0.0033 (at an object distance of 400mm);

[0134] Where fy is the focal length of the liquid lens L1, the liquid lens L1 changes its own performance by changing the operating voltage, thereby changing the focal length and ultimately achieving the purpose of focusing.

[0135] The liquid focusing lens in this embodiment satisfies the following relationship:

[0136] f4 / f = 0.68;

[0137] Where f4 is the focal length of the combination of the third lens G3, the fourth lens G4, and the fifth lens G5.

[0138] The parameters of the liquid focusing lens in this embodiment are shown in Table 3.

[0139] Table 3

[0140]

[0141] The shape, material, refractive index, and Abbe number parameters of each lens in this embodiment are shown in Table 4.

[0142] Table 4

[0143]

[0144] In Table 4, when the radius of curvature is Infinity, it indicates that the surface is a plane.

[0145] Figure 4 This is a schematic diagram of the MTF in this embodiment. The OTF coefficient corresponding to the spatial frequency of 145LP / mm in the center field of view is above 0.22, and the lens achieves high resolution.

[0146] The rest is the same as in Example 1.

[0147] The parts or structures not specifically described in this utility model can be made using existing technology or existing products, and will not be elaborated here.

[0148] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A liquid focus lens, characterized by, The liquid focusing lens comprises a first lens group, a second lens group and a third lens group arranged in sequence from an object side to an image side, the second lens group comprises a liquid lens, the focal length of the liquid lens is changed by changing the curvature of the liquid surface, and finally the focusing purpose is achieved; The first lens group satisfies the relationship: -6 Wherein, f is the focal length of the liquid focusing lens, and f1 is the focal length of the first lens group.

2. A liquid focus lens according to claim 1, wherein, The first lens group comprises a first lens and a second lens arranged in sequence from an object side to an image side, and the first lens and the second lens satisfy the following conditions: Nd (G1) is the refractive index of the first lens, and Nd (G2) is the refractive index of the second lens. The first lens is a meniscus positive lens, and the convex surface faces the object plane; the second lens is a plano-concave negative lens, and the concave surface faces the image plane. The first lens is a plano-convex positive lens, and the convex surface faces the object plane; the second lens is a double-concave negative lens.

3. A liquid focus lens according to claim 2, wherein, The liquid lens satisfies the relationship:

4. A liquid focus lens according to claim 2, wherein, -0.015 5. The liquid focus lens of claim 1, wherein, Wherein, fy is the focal length of the liquid lens. The liquid lens satisfies the following conditions: The length of the liquid lens before and after the liquid lens itself is greater than or equal to 3.5mm.

6. The liquid focusing lens of claim 1, wherein The third lens group comprises a third lens and a fourth lens arranged in sequence from an object side to an image side, the third lens is a double-convex positive diopter lens, and the fourth lens is a double-concave negative diopter lens; The third lens and the fourth lens satisfy the following conditions:

7. The liquid focus lens of claim 1, wherein, Nd (G3) is the refractive index of the third lens, and Nd (G4) is the refractive index of the fourth lens. The third lens group comprises a third lens, a fourth lens and a fifth lens arranged in sequence from an object side to an image side, the third lens is a double-convex positive diopter lens, and the fourth lens is a double-concave negative diopter lens; The third lens, the fourth lens and the fifth lens satisfy the following conditions: Nd (G3) is the refractive index of the third lens, Nd (G4) is the refractive index of the fourth lens, and Nd (G5) is the refractive index of the fifth lens. The liquid focusing lens satisfies the relationship:

8. The liquid focusing lens of claim 1, wherein, -1 Wherein, f is the focal length of the liquid focusing lens, and f4 is the combined focal length of the third lens, the fourth lens and the fifth lens. The third lens and the fourth lens are not glued, and at this time, the third lens and the fourth lens satisfy the following conditions: -20 Wherein, f is the focal length of the liquid focusing lens, and f2 is the combined focal length of the third lens and the fourth lens. The third lens and the fourth lens are glued into a first glued lens group, and the first glued lens group satisfies the relationship:

9. A liquid focus lens according to claim 8, wherein, -20 Wherein, f is the focal length of the liquid focusing lens, and f3 is the focal length of the first glued lens group. The fifth lens is a double-convex positive diopter lens.

10. A liquid focus lens according to claim 7 or 8, wherein, The fifth lens is a plano-convex positive diopter lens, and the convex surface faces the image plane. ​ ​ 11. A liquid focus lens according to claim 7 or 8, wherein, ​ ​ ​ 12. The liquid focus lens of claim 8, wherein, ​ 13. The liquid focus lens of claim 8, wherein, ​ 14. The liquid focus lens of claim 1, wherein, A diaphragm is arranged between the second lens group and the third lens.

15. The liquid focus lens of claim 1, wherein, The liquid focusing lens has a focal length f=16mm, a diaphragm value FNO=5.6, a half image height ≤4.8mm, and a total length within 30mm.

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