A biometric iris lens

Abstract

This invention relates to the field of optics, specifically to a biometric iris recognition lens. The biometric iris recognition lens comprises a first fixed lens group with positive optical power, a zoom lens group with negative optical power, an aperture stop, a second fixed lens group with positive optical power, a focusing lens group with negative optical power, and a third fixed lens group with positive optical power; 4 < ft / fw < 5; 1.15 < fnot / fnow < 1.25; ft is the focal length of the biometric iris recognition lens in telephoto mode, fw is the focal length of the biometric iris recognition lens in wide-angle mode, fnot is the aperture number of the biometric iris recognition lens in telephoto mode, and fnow is the aperture number of the biometric iris recognition lens in wide-angle mode. The biometric iris recognition lens can stably acquire images with stable brightness at a certain distance, facilitating iris acquisition and increasing the application range of the biometric iris recognition lens.

Description

Technical Field

[0001] This invention relates to the field of optics, specifically to a biometric iris lens. Background Technology

[0002] The human eye is composed of the sclera, iris, pupil, lens, and retina. The iris is a ring-shaped structure located between the black pupil and the white sclera, containing numerous intricate features such as spots, filaments, coronas, stripes, and crypts. Furthermore, once formed during fetal development, the iris remains unchanged throughout life. These characteristics determine the uniqueness of the iris, and consequently, the uniqueness of one's identity. Therefore, the iris can be used as a means of identifying each individual.

[0003] Biometric iris recognition cameras are primarily based on the iris of a biometric entity to identify each individual. Currently, they are mainly used in access control, security, and consumer applications. However, the process of acquiring iris images is challenging due to changes in lighting conditions, such as day and night or varying environments, which increases the requirements for the application scenarios of biometric iris recognition cameras. Summary of the Invention

[0004] This invention addresses existing technical problems by providing a biometric iris lens that can stably acquire images with stable brightness at a certain distance, facilitating iris acquisition and expanding its application range.

[0005] The technical solution provided by this invention is as follows:

[0006] A biometric iris lens, comprising, from the object plane side to the image plane side, a first fixed lens group with positive optical power, a zoom lens group with negative optical power, an aperture stop, a second fixed lens group with positive optical power, a focusing lens group with negative optical power, and a third fixed lens group with positive optical power; the biometric iris lens satisfies the following conditions: 4 < ft / fw < 5; 1.15 < fnot / fnow < 1.25; where ft is the focal length of the biometric iris lens in telephoto mode, fw is the focal length of the biometric iris lens in wide-angle mode, fnot is the aperture number of the biometric iris lens in telephoto mode, and fnow is the aperture number of the biometric iris lens in wide-angle mode.

[0007] In this technical solution, through the above-mentioned structure and parameter limitations, the biometric iris lens can stably acquire images with stable brightness at a certain distance, which facilitates the acquisition of iris images by the biometric iris lens. The biometric iris lens has good infrared confocal performance, taking into account the acquisition of iris images in both visible and infrared light, thus increasing the application range of the biometric iris lens.

[0008] Preferably, the first fixed lens group consists of a first fixed lens with negative optical power, a second fixed lens with positive optical power, a third fixed lens with positive optical power, and a fourth fixed lens with positive optical power, from the object plane side to the image plane side, and the first fixed lens and the second fixed lens are cemented together.

[0009] or

[0010] The first fixed lens group consists of a first fixed lens with negative optical power, a second fixed lens with positive optical power, and a third fixed lens with positive optical power, arranged sequentially from the object plane side to the image plane side. The first fixed lens and the second fixed lens are cemented together.

[0011] Preferably, the zoom lens group consists of a first zoom lens with negative optical power, a second zoom lens with negative optical power, a third zoom lens with positive optical power, and a fourth zoom lens with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0012] Preferably, the second fixed lens group consists of a fifth fixed lens with positive optical power, a sixth fixed lens with positive optical power, a seventh fixed lens with negative optical power, and an eighth fixed lens with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0013] Preferably, the second fixed lens group includes at least one set of cemented lenses.

[0014] In this technical solution, the use of cemented lenses reduces the possibility of excessive coma and spherical aberration in biometric iris recognition lenses, thereby increasing the imaging quality of biometric iris recognition lenses.

[0015] Preferably, the focusing lens group is a first focusing lens with negative optical power;

[0016] The third fixed lens group is a ninth fixed lens with positive optical power.

[0017] Preferably, the biometric iris lens comprises at most two aspherical lenses.

[0018] In this technical solution, by setting up to two aspherical lenses, the possibility of excessive coma and spherical aberration in the biometric iris lens is reduced, and the number of lenses in the biometric iris lens is also reduced, thereby reducing the cost of the biometric iris lens.

[0019] Preferably, the lens closest to the object surface in the second fixed lens group is an aspherical lens.

[0020] In this technical solution, by defining the lens surface shape of the second fixed lens group closest to the object surface, the second fixed lens group can reliably receive the light path emitted by the aperture, reducing the possibility of light dissipation on the second fixed lens group and increasing the imaging quality of the biometric iris lens.

[0021] Preferably, the biometric iris lens satisfies the following condition:

[0022] XG2 / TTL > 0.15;

[0023] Wherein, XG2 is the moving distance of the zoom lens group, and TTL is the total optical length of the biometric iris lens.

[0024] In this technical solution, by setting up a zoom lens group with a large moving distance, the zoom stability of the biometric iris recognition lens is effectively increased, and the imaging quality of the biometric iris recognition lens is improved.

[0025] Preferably, the biometric iris lens satisfies the following condition:

[0026] 0.7 < |fG2 / fw| < 1;

[0027] 1.2 < |fG4 / fw| < 2.5;

[0028] Wherein, fG2 is the focal length of the zoom lens group, and fG4 is the focal length of the focusing lens group.

[0029] In this technical solution, by limiting the above parameters, the zoom lens group can achieve stable zooming, while the focusing lens group can reliably correct the optical path, thereby increasing the imaging quality of the biometric iris lens.

[0030] Compared with existing technologies, the biometric iris lens provided by this invention has the following beneficial effects:

[0031] 1. With the above-mentioned structure and parameter limitations, the biometric iris lens can stably acquire images with stable brightness at a certain distance, which facilitates the biometric iris lens to collect irises and increases the application range of the biometric iris lens.

[0032] 2. By defining the lens surface shape closest to the object surface in the second fixed lens group, the second fixed lens group can reliably receive the light path emitted by the aperture, reducing the possibility of light dissipation in the second fixed lens group and increasing the imaging quality of the biometric iris lens.

[0033] 3. With the above parameters in place, the zoom lens group can zoom stably, while the focusing lens group can reliably correct the optical path, thus increasing the imaging quality of the biometric iris recognition lens. Attached Figure Description

[0034] The preferred embodiments will now be described in a clear and easy-to-understand manner, with reference to the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of a biometric iris lens.

[0035] Figure 1 This is a schematic diagram of the structure of a biometric iris lens according to the present invention;

[0036] Figure 2 This invention relates to a coma diagram of the telescopic state of a biometric iris lens;

[0037] Figure 3 This is an aberration diagram of the telescopic state of a biometric iris lens according to the present invention;

[0038] Figure 4 This invention relates to a coma diagram of the wide-angle state of a biometric iris lens;

[0039] Figure 5 This is an aberration diagram of a wide-angle state of a biometric iris lens according to the present invention;

[0040] Figure 6 This is a schematic diagram of another biometric iris lens according to the present invention;

[0041] Figure 7 This is another coma diagram of the telescopic state of the biometric iris lens according to the present invention;

[0042] Figure 8 This is another aberration diagram of the telescopic state of the biometric iris lens of the present invention;

[0043] Figure 9 This is another coma diagram of the wide-angle state of the biometric iris lens according to the present invention;

[0044] Figure 10 This is another aberration diagram of the wide-angle state of the biometric iris lens of the present invention;

[0045] Figure 11 This is a schematic diagram of the structure of another biometric iris lens of the present invention;

[0046] Figure 12 This invention provides another coma diagram of the telescopic state of a biometric iris lens;

[0047] Figure 13 This is another aberration diagram of the telescopic state of a biometric iris lens according to the present invention;

[0048] Figure 14 This invention provides another coma diagram of the wide-angle state of a biometric iris lens;

[0049] Figure 15This is another aberration map of the wide-angle state of the biometric iris lens of the present invention.

[0050] Explanation of reference numerals: G1, First fixed lens group; G2, Zoom lens group; G3, Second fixed lens group; G4, Focusing lens group; G5, Third fixed lens group; G6, Auxiliary component; a1, First fixed lens; a2, Second fixed lens; a3, Third fixed lens; a4, Fourth fixed lens; a5, Fifth fixed lens; a6, Sixth fixed lens; a7, Seventh fixed lens; a8, Eighth fixed lens; a9, Ninth fixed lens; b1, First zoom lens; b2, Second zoom lens; b3, Third zoom lens; b4, Fourth zoom lens; c1, First focusing lens; STO, Aperture stop; CG1, First protective glass; CG2, Second protective glass. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0053] Example 1

[0054] like Figure 1 As shown, a biometric iris lens is composed of, from the object plane side to the image plane side, a first fixed lens group G1 with positive optical power, a zoom lens group G2 with negative optical power, an aperture stop STO, a second fixed lens group G3 with positive optical power, a focusing lens group G4 with negative optical power, and a third fixed lens group G5 with positive optical power.

[0055] The biometric iris camera satisfies the following condition:

[0056] 4 < ft / fw < 5;

[0057] 1.15 < fnot / fnow < 1.25;

[0058] Wherein, ft is the focal length of the biometric iris lens in telephoto mode, fw is the focal length of the biometric iris lens in wide-angle mode, fnot is the aperture number of the biometric iris lens in telephoto mode, and fnow is the aperture number of the biometric iris lens in wide-angle mode.

[0059] In this embodiment, through the above-described structure and parameter limitations, the biometric iris lens can stably acquire images with stable brightness at a certain distance, facilitating iris acquisition by the biometric iris lens. The biometric iris lens has good infrared confocal performance, taking into account both visible light and infrared light iris image acquisition, thus increasing the application range of the biometric iris lens.

[0060] The first fixed lens group G1 consists of a first fixed lens a1 with negative optical power, a second fixed lens a2 with positive optical power, a third fixed lens a3 with positive optical power, and a fourth fixed lens a4 with positive optical power, from the object plane side to the image plane side. The first fixed lens a1 and the second fixed lens a2 are cemented together.

[0061] or

[0062] The first fixed lens group G1 consists of a first fixed lens a1 with negative optical power, a second fixed lens a2 with positive optical power, and a third fixed lens a3 with positive optical power, arranged sequentially from the object plane side to the image plane side. The first fixed lens a1 and the second fixed lens a2 are cemented together.

[0063] The zoom lens group G2 consists of a first zoom lens b1 with negative optical power, a second zoom lens b2 with negative optical power, a third zoom lens b3 with positive optical power, and a fourth zoom lens b4 with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0064] The second fixed lens group G3 consists of a fifth fixed lens a5 with positive optical power, a sixth fixed lens a6 with positive optical power, a seventh fixed lens a7 with negative optical power, and an eighth fixed lens a8 with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0065] The second fixed lens group G3 contains at least one set of cemented lenses.

[0066] In this embodiment, by setting up a cemented lens, the possibility of excessive coma and spherical aberration in the biometric iris lens is reduced, thereby increasing the imaging quality of the biometric iris lens.

[0067] The focusing lens group G4 is a first focusing lens c1 with negative optical power;

[0068] The third fixed lens group G5 is a ninth fixed lens a9 with positive optical power.

[0069] The biometric iris camera contains at most two aspherical lenses.

[0070] In this embodiment, by using at most two aspherical lenses, the possibility of excessive coma and spherical aberration in the biometric iris lens is reduced, and the number of lenses in the biometric iris lens is also reduced, thereby reducing the cost of the biometric iris lens.

[0071] The lens closest to the object surface in the second fixed lens group G3 is an aspherical lens.

[0072] By defining the lens surface shape of the second fixed lens group G3 closest to the object plane, the second fixed lens group G3 can reliably receive the light path emitted by the aperture STO, reducing the possibility of light dissipation on the second fixed lens group G3 and increasing the imaging quality of the biometric iris lens.

[0073] The biometric iris camera satisfies the following condition:

[0074] XG2 / TTL > 0.15;

[0075] Wherein, XG2 is the moving distance of the zoom lens group G2, and TTL is the total optical length of the biometric iris lens.

[0076] By using the G2 zoom lens group with a large moving distance, the zoom stability of the biometric iris recognition lens is effectively increased, thus improving the image quality of the biometric iris recognition lens.

[0077] The biometric iris camera satisfies the following condition:

[0078] 0.7 < |fG2 / fw| < 1;

[0079] 1.2 < |fG4 / fw| < 2.5;

[0080] Wherein, fG2 is the focal length of the zoom lens group G2, and fG4 is the focal length of the focusing lens group G4.

[0081] With the above parameters defined, the zoom lens group G2 can zoom stably, while the focusing lens group G4 can reliably correct the optical path, thus increasing the imaging quality of the biometric iris lens.

[0082] Example 2

[0083] like Figures 1 to 5 As shown, a biometric iris lens is composed of, from the object plane side to the image plane side, a first fixed lens group G1 with positive optical power, a zoom lens group G2 with negative optical power, an aperture stop STO, a second fixed lens group G3 with positive optical power, a focusing lens group G4 with negative optical power, a third fixed lens group G5 with positive optical power, and an auxiliary component G6.

[0084] The first fixed lens group G1 consists of a first fixed lens a1 with negative optical power, a second fixed lens a2 with positive optical power, a third fixed lens a3 with positive optical power, and a fourth fixed lens a4 with positive optical power, from the object plane side to the image plane side. The first fixed lens a1 and the second fixed lens a2 are cemented together.

[0085] The zoom lens group G2 consists of a first zoom lens b1 with negative optical power, a second zoom lens b2 with negative optical power, a third zoom lens b3 with positive optical power, and a fourth zoom lens b4 with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0086] The second fixed lens group G3 consists of a fifth fixed lens a5 with positive optical power, a sixth fixed lens a6 with positive optical power, a seventh fixed lens a7 with negative optical power, and an eighth fixed lens a8 with positive optical power, from the object plane side to the image plane side; the sixth fixed lens a6 and the seventh fixed lens a7 are cemented together.

[0087] The focusing lens group G4 is a first focusing lens c1 with negative optical power.

[0088] The third fixed lens group G5 is a ninth fixed lens a9 with positive optical power.

[0089] The auxiliary component G6 is a first protective glass CG1.

[0090] The basic lens data of a biometric iris lens of this embodiment is shown in Table 1, the variable parameters in Table 1 are shown in Table 2, and the aspherical coefficients are shown in Table 3.

[0091] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0092] In Table 2, the WIDE column indicates the specific values ​​of each variable parameter when a biometric iris lens is in the wide-angle position, and the TELE column indicates the specific values ​​of each variable parameter when a biometric iris lens is in the telephoto position.

[0093] In Table 3, K is the conic coefficient, and e is the scientific notation, for example, e-05 represents 10. -5 .

[0094] Table 1

[0095] Face number Surface type radius of curvature / mm Center thickness / mm Refractive index Abbe number OBJ S1 spherical 34.98 0.70 1.85 23.78 S2 spherical 23.76 3.69 1.44 94.58 S3 spherical 437.06 0.15 S4 spherical 18.02 3.46 1.44 94.58 S5 spherical 85.66 0.15 S6 spherical 12.78 2.40 1.59 68.63 S7 spherical 20.44 D1 S8 spherical 13.39 0.50 2.00 29.13 S9 spherical 4.34 2.16 S10 spherical -27.68 0.50 2.00 29.13 S11 spherical 13.63 0.15 S12 spherical 8.69 1.61 1.95 17.98 S13 spherical -37.83 0.63 S14 spherical -8.26 0.50 1.49 70.45 S15 spherical 1386.90 D2 STO spherical INF 0.50 S17 aspherical 6.89 2.53 1.81 40.73 S18 aspherical -18.04 0.15 S19 spherical 14.93 1.15 1.44 94.58 S20 spherical -21.33 0.50 1.75 25.05 S21 spherical 5.01 0.94 S22 spherical 7.03 1.62 1.44 94.58 S23 spherical -7.13 D3 S24 spherical -43.44 0.50 1.54 47.20 S25 spherical 8.66 D4 S26 spherical 11.57 1.12 1.80 46.50 S27 spherical 38.74 4.00 S28 spherical INF 0.80 1.52 64.20 S29 spherical INF 0.10 IMG

[0096] Table 2

[0097] WIDE TELE D1 0.7 9.76 D2 9.76 0.7 D3 0.7 2.03 D4 3.34 2.01

[0098] Table 3

[0099]

[0100] In this embodiment, TTL = 45.01mm, fw = 6.3mm, ft = 30mm, ft / fw = 4.76, fnow = 2.54, fnot = 3.01, and fnot / fnow = 1.19;

[0101] Wherein, TTL is the total optical length of the biometric iris lens, ft is the focal length of the biometric iris lens in telephoto mode, fw is the focal length of the biometric iris lens in wide-angle mode, fnot is the aperture number of the biometric iris lens in telephoto mode, and fnow is the aperture number of the biometric iris lens in wide-angle mode.

[0102] XG2=9.06mm, XG2 / TTL=0.2;

[0103] Wherein, XG2 is the moving distance of the zoom lens group G2.

[0104] fG2 = -4.95 mm, |fG2 / fw| = 0.79;

[0105] fG4 = -13.31 mm, |fG4 / fw| = 2.1;

[0106] Wherein, fG2 is the focal length of the zoom lens group G2, and fG4 is the focal length of the focusing lens group G4.

[0107] Example 3

[0108] like Figures 6 to 10 As shown, a biometric iris lens is composed of, from the object plane side to the image plane side, a first fixed lens group G1 with positive optical power, a zoom lens group G2 with negative optical power, an aperture stop STO, a second fixed lens group G3 with positive optical power, a focusing lens group G4 with negative optical power, a third fixed lens group G5 with positive optical power, and an auxiliary component G6.

[0109] The first fixed lens group G1 consists of a first fixed lens a1 with negative optical power, a second fixed lens a2 with positive optical power, and a third fixed lens a3 with positive optical power, arranged sequentially from the object plane side to the image plane side. The first fixed lens a1 and the second fixed lens a2 are cemented together.

[0110] The zoom lens group G2 consists of a first zoom lens b1 with negative optical power, a second zoom lens b2 with negative optical power, a third zoom lens b3 with positive optical power, and a fourth zoom lens b4 with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0111] The second fixed lens group G3 consists of a fifth fixed lens a5 with positive optical power, a sixth fixed lens a6 with positive optical power, a seventh fixed lens a7 with negative optical power, and an eighth fixed lens a8 with positive optical power, from the object plane side to the image plane side; the sixth fixed lens a6 and the seventh fixed lens a7 are cemented together.

[0112] The focusing lens group G4 is a first focusing lens c1 with negative optical power.

[0113] The third fixed lens group G5 is a ninth fixed lens a9 with positive optical power.

[0114] The auxiliary component G6 is a first protective glass CG1.

[0115] The basic lens data of a biometric iris lens of this embodiment is shown in Table 4, the variable parameters in Table 4 are shown in Table 5, and the aspherical coefficients are shown in Table 6.

[0116] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0117] In Table 5, the WIDE column indicates the specific values ​​of each variable parameter when a biometric iris lens is in the wide-angle position, and the TELE column indicates the specific values ​​of each variable parameter when a biometric iris lens is in the telephoto position.

[0118] In Table 6, K is the conic coefficient, and e is the scientific notation, for example, e-05 represents 10. -5 .

[0119] Table 4

[0120] Face number Surface type radius of curvature / mm Center thickness / mm Refractive index Abbe number OBJ S1 spherical 28.04 0.70 1.85 23.78 S2 spherical 16.36 4.08 1.50 81.61 S3 spherical -35275.00 0.15 S4 spherical 14.26 2.50 1.80 46.50 S5 spherical 29.40 D1 S6 spherical 12.82 0.53 2.00 29.13 S7 spherical 4.52 2.70 S8 aspherical -15.29 0.50 1.58 59.46 S9 aspherical 17.28 0.15 S10 spherical 11.02 1.54 1.95 17.98 S11 spherical -47.78 0.45 S12 spherical -13.62 0.50 1.90 31.32 S13 spherical INF D2 STO spherical INF 0.50 S15 aspherical 6.51 2.16 1.81 40.73 STO aspherical -20.80 0.15 S17 spherical 8.17 1.46 1.50 81.61 S18 spherical -10.58 0.50 1.90 31.32 S19 spherical 4.50 1.39 S20 spherical 7.86 1.36 1.62 63.40 S21 spherical -9.27 D4 S22 spherical -212.36 0.50 1.75 25.05 S23 spherical 7.81 D4 S24 spherical 13.94 1.25 1.83 42.72 S25 spherical -91.28 4.00 S26 spherical INF 0.80 1.52 64.20 S27 spherical INF 0.10 IMG

[0121] Table 5

[0122]

[0123]

[0124] Table 6

[0125]

[0126] In this embodiment, TTL = 45mm, fw = 5.7mm, ft = 27.49mm, ft / fw = 4.82, fnow = 2.51, fnot = 3, fnot / fnow = 1.195;

[0127] Wherein, TTL is the total optical length of the biometric iris lens, ft is the focal length of the biometric iris lens in telephoto mode, fw is the focal length of the biometric iris lens in wide-angle mode, fnot is the aperture number of the biometric iris lens in telephoto mode, and fnow is the aperture number of the biometric iris lens in wide-angle mode.

[0128] XG2=10.93mm, XG2 / TTL=0.24;

[0129] Wherein, XG2 is the moving distance of the zoom lens group G2.

[0130] fG2 = -5.32 mm, |fG2 / fw| = 0.93;

[0131] fG4 = -10mm, |fG4 / fw| = 1.75;

[0132] Wherein, fG2 is the focal length of the zoom lens group G2, and fG4 is the focal length of the focusing lens group G4.

[0133] Example 4

[0134] like Figures 11 to 15 As shown, a biometric iris lens is composed of, from the object plane side to the image plane side, a first fixed lens group G1 with positive optical power, a zoom lens group G2 with negative optical power, an aperture stop STO, a second fixed lens group G3 with positive optical power, a focusing lens group G4 with negative optical power, a third fixed lens group G5 with positive optical power, and an auxiliary component G6.

[0135] The first fixed lens group G1 consists of a first fixed lens a1 with negative optical power, a second fixed lens a2 with positive optical power, and a third fixed lens a3 with positive optical power, arranged sequentially from the object plane side to the image plane side. The first fixed lens a1 and the second fixed lens a2 are cemented together.

[0136] The zoom lens group G2 consists of a first zoom lens b1 with negative optical power, a second zoom lens b2 with negative optical power, a third zoom lens b3 with positive optical power, and a fourth zoom lens b4 with negative optical power, arranged sequentially from the object plane side to the image plane side.

[0137] The second fixed lens group G3 consists of a fifth fixed lens a5 with positive optical power, a sixth fixed lens a6 with positive optical power, a seventh fixed lens a7 with negative optical power, and an eighth fixed lens a8 with positive optical power, from the object plane side to the image plane side; the seventh fixed lens a7 and the eighth fixed lens a8 are cemented together.

[0138] The focusing lens group G4 is a first focusing lens c1 with negative optical power.

[0139] The third fixed lens group G5 is a ninth fixed lens a9 with positive optical power.

[0140] The auxiliary component G6 consists of a first protective glass CG1 and a second protective glass CG2.

[0141] The basic lens data of a biometric iris lens of this embodiment is shown in Table 7, the variable parameters in Table 7 are shown in Table 8, and the aspherical coefficients are shown in Table 9.

[0142] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0143] In Table 8, the WIDE column indicates the specific values ​​of each variable parameter when a biometric iris lens is in the wide-angle position, and the TELE column indicates the specific values ​​of each variable parameter when a biometric iris lens is in the telephoto position.

[0144] In Table 9, K is the conic coefficient, and e is the scientific notation, for example, e-05 represents 10. -5 .

[0145] Table 7

[0146] Face number Surface type radius of curvature / mm Center thickness / mm Refractive index Abbe number OBJ S1 spherical 25.82 0.70 1.85 25.15 S2 spherical 16.12 4.18 1.50 81.61 S3 spherical -1017.00 0.15 S4 spherical 13.92 2.58 1.77 49.62 S5 spherical 27.96 D1 S6 spherical 11.03 0.60 2.00 25.46 S7 spherical 4.32 2.47 S8 aspherical -53.85 0.60 1.81 40.73 S9 aspherical 11.34 0.15 S10 spherical 9.79 1.93 1.95 17.98 S11 spherical -22.09 0.38 S12 spherical -11.32 0.60 1.90 31.32 S13 spherical 330.20 D2 STO spherical INF 1.00 S15 aspherical 8.67 1.53 1.81 40.73 STO aspherical -119.68 0.24 S17 spherical -2727.70 1.73 1.44 95.10 S18 spherical -6.94 0.15 S19 spherical 16.05 0.60 1.86 30.00 S20 spherical 4.27 2.03 1.44 95.10 S21 spherical -9.38 D3 S22 spherical 58.26 0.60 1.62 58.12 S23 spherical 5.28 D4 S24 spherical 5.07 1.34 1.44 95.10 S25 spherical 7.32 3.53 S26 spherical INF 0.30 1.52 64.21 S27 spherical INF 0.80 S28 spherical INF 0.50 1.52 64.21 S29 spherical INF 0.40 IMG

[0147] Table 8

[0148]

[0149]

[0150] Table 9

[0151]

[0152] In this embodiment, TTL = 45mm, fw = 6.3mm, ft = 30mm, ft / fw = 4.76, fnow = 2.51, fnot = 3.01, and fnot / fnow = 1.2;

[0153] Wherein, TTL is the total optical length of the biometric iris lens, ft is the focal length of the biometric iris lens in telephoto mode, fw is the focal length of the biometric iris lens in wide-angle mode, fnot is the aperture number of the biometric iris lens in telephoto mode, and fnow is the aperture number of the biometric iris lens in wide-angle mode.

[0154] XG2=10.56mm, XG2 / TTL=0.23;

[0155] Wherein, XG2 is the moving distance of the zoom lens group G2.

[0156] fG2 = -5.62 mm, |fG2 / fw| = 0.89;

[0157] fG4 = -9.37 mm, |fG4 / fw| = 1.49;

[0158] Wherein, fG2 is the focal length of the zoom lens group G2, and fG4 is the focal length of the focusing lens group G4.

[0159] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A biometric iris recognition lens, characterized in that, The biometric iris lens consists of, from the object plane side to the image plane side, a first fixed lens group with positive optical power, a zoom lens group with negative optical power, an aperture stop, a second fixed lens group with positive optical power, a focusing lens group with negative optical power, and a third fixed lens group with positive optical power. The zoom lens group consists of a first zoom lens with negative optical power, a second zoom lens with negative optical power, a third zoom lens with positive optical power, and a fourth zoom lens with negative optical power, arranged sequentially from the object plane side to the image plane side. The second fixed lens group consists of a fifth fixed lens with positive optical power, a sixth fixed lens with positive optical power, a seventh fixed lens with negative optical power, and an eighth fixed lens with positive optical power, sequentially from the object plane side to the image plane side. The focusing lens group is a first focusing lens with negative optical power; The third fixed lens group is a ninth fixed lens with positive optical power; The biometric iris camera satisfies the following condition: 4 < ft / fw < 5; 1.15 < fnot / fnow < 1.25; Wherein, ft is the focal length of the biometric iris lens in telephoto mode, fw is the focal length of the biometric iris lens in wide-angle mode, fnot is the aperture number of the biometric iris lens in telephoto mode, and fnow is the aperture number of the biometric iris lens in wide-angle mode.

2. The biometric iris lens according to claim 1, characterized in that: The first fixed lens group consists of a first fixed lens with negative optical power, a second fixed lens with positive optical power, a third fixed lens with positive optical power, and a fourth fixed lens with positive optical power, from the object plane side to the image plane side. The first fixed lens and the second fixed lens are cemented together. or The first fixed lens group consists of a first fixed lens with negative optical power, a second fixed lens with positive optical power, and a third fixed lens with positive optical power, arranged sequentially from the object plane side to the image plane side. The first fixed lens and the second fixed lens are cemented together.

3. The biometric iris lens according to claim 1, characterized in that: The second fixed lens group includes at least one set of cemented lenses.

4. The biometric iris lens according to claim 1, characterized in that: The biometric iris camera contains at most two aspherical lenses.

5. A biometric iris lens according to claim 4, characterized in that: The lens closest to the object surface in the second fixed lens group is an aspherical lens.

6. The biometric iris lens according to claim 1, characterized in that: The biometric iris camera satisfies the following condition: XG2 / TTL > 0.15; Wherein, XG2 is the moving distance of the zoom lens group, and TTL is the total optical length of the biometric iris lens.

7. A biometric iris lens according to claim 1, characterized in that: The biometric iris camera satisfies the following condition: 0.7 < |fG2 / fw| < 1; 1.2 < |fG4 / fw| < 2.5; Wherein, fG2 is the focal length of the zoom lens group, and fG4 is the focal length of the focusing lens group.

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