Ultra-wide-angle day and night confocal security lens

Abstract

The present invention discloses an ultra-wide-angle day / night confocal security lens. The lens comprises, arranged from front to back, a meniscus positive lens, a first biconcave negative lens, a concave-convex positive lens, a first concave-convex negative lens, a second concave-convex negative lens, a first biconvex positive lens, a second biconvex positive lens, a third biconvex positive lens, a second biconcave negative lens, and a flat protective glass. The lens achieves a broad confocal design for visible and near-infrared light, with a negligible near-infrared focal shift of 9.86 μm. It also achieves 110° ultra-wide-angle imaging and a relative illumination of better than 98% across the entire field of view, providing uniform high brightness for security lenses.

Description

Technical Field

[0001] The present invention relates to the technical field of security lenses, and in particular to an ultra-wide-angle day and night confocal security lens. Background Art

[0002] Security lenses are essential for the safety of modern society. They are deployed at various road intersections, shopping malls, and schools. Urban security monitoring and highway traffic supervision are the most widely used. Currently, the security lenses available on the market include a wide-field-of-view, high-resolution CCTV system surveillance lens designed by Zhao Yingming et al. This system utilizes a complex 9-element reverse telephoto structure, with 6 glass lenses in the front group and 3 in the rear group. The full field of view is 80°. F The number is 3, the system focal length is 5 mm , using visible light design. Matching the pixel size of 7.5μ m ×7.5μ m 1 / 2 inchCCD Image sensor. At Nyquist frequency 67 lp / mm Full field of view MTF Close to 0.65; at 220 lp / mm Full field of view MTF Although this lens achieves excellent image quality within an 80° field of view, fixed-focus security lenses actually require ultra-wide angles to better meet the needs of a wide range of applications. It would also be best if a near-infrared band design could be added to achieve day and night focus. Therefore, there is still significant room for improvement in existing security lenses. Summary of the Invention

[0003] The present invention aims to solve the problem of small field of view of existing security lenses and provide an ultra-wide-angle day and night confocal security lens.

[0004] To solve the above problems, the present invention is achieved through the following technical solutions:

[0005] The ultra-wide-angle day and night confocal security lens consists of a meniscus positive lens, a first biconcave negative lens, a concave-convex positive lens, a first concave-convex negative lens, a second concave-convex negative lens, a first biconvex positive lens, a second biconvex positive lens, a third biconvex positive lens, a second biconcave negative lens, and a flat protective glass. The meniscus positive lens and the first biconcave negative lens form a doublet lens; the curvature radius of the front surface of the meniscus positive lens is r 1 is -22 mm ≤ r 1≤-18 mm , the radius of curvature of the rear surface r 2 is -17 mm ≤ r 2≤-14 mm , the center thickness of the front and rear surfaces d 1 is 2.6 mm ≤ d 1≤3 mm , D Refractive index under light n d1 1.7≤ n d1 ≤1.8, D Abbe number under light v d1 50≤ v d1 ≤54; first biconcave negative lens, the radius of curvature of the front surface r 2 is -17 mm ≤ r 2≤-14 mm , back surface curvature radius r 3 is 11 mm ≤ r 3≤14 mm , the center thickness of the front and rear surfaces d 2 is 0.5 mm ≤ d 2≤0.7 mm , D Refractive index under light n d2 1.4≤ n d2 ≤1.5, D Abbe number under light v d2 79≤ v d2 ≤82. The concave-convex positive lens and the first concave-convex negative lens form a doublet lens; the curvature radius of the front surface of the concave-convex positive lens r 4 for 5 mm ≤ r 4≤7 mm , the radius of curvature of the rear surface r 5 for 7 mm ≤ r 5≤9 mm , the center thickness of the front and rear surfaces d 3 for 2 mm ≤ d 3≤3 mm , D Refractive index under light n d3 1.8≤ n d3 ≤1.9, D Abbe number under light v d3 30≤ vd3 ≤33; first concave-convex negative lens, front surface curvature radius r 5 for 7 mm ≤ r 5≤9 mm , back surface curvature radius r 6 for 2 mm ≤ r 6≤3 mm , the center thickness of the front and rear surfaces d 4 is 0.6 mm ≤ d 4≤0.8 mm , D Refractive index under light n d4 1.6≤ n d4 ≤1.7, D Abbe number under light v d4 42≤ v d4 ≤46. The second concave-convex negative lens and the first biconvex positive lens form a doublet lens; the curvature radius of the front surface of the second concave-convex negative lens is r 7 is 20 mm ≤ r 7≤23 mm , the radius of curvature of the rear surface r 8 to 6 mm ≤ r 8≤8 mm , the center thickness of the front and rear surfaces d 5 for 2.7 mm ≤ d 5≤3 mm , D Refractive index under light n d5 1.7≤ n d5 ≤1.8, D Abbe number under light v d5 50≤ v d5 ≤54; first biconvex positive lens, curvature radius of the front surface r 8 to 6 mm ≤ r 8≤8 mm , back surface curvature radius r 9 is -5 mm ≤ r 9≤-3 mm , the center thickness of the front and rear surfaces d 6 for 2.3 mm ≤ d 6≤2.6 mm, D Refractive index under light n d6 1.4≤ n d6 ≤1.6, D Abbe number under light v d6 82≤ v d6 ≤85. The second biconvex positive lens is a single lens with a curvature radius of the front surface r 10 is 9 mm ≤ r 10 ≤11 mm , the curvature radius of the back r 11 -9 mm ≤ r 11 ≤-7 mm , the center thickness of the front and rear surfaces d 7 is 2.3 mm ≤ d 7≤2.7 mm , D Refractive index under light n d7 1.5≤ n d7 ≤1.6, D Abbe number under light v d7 72≤ v d7 <≤78. The third biconvex positive lens and the second biconcave negative lens form a doublet lens; the third biconvex positive lens has a front surface curvature radius of r 12 is 10 mm ≤ r 12 ≤13 mm , the radius of curvature of the rear surface r 13 -8 mm ≤ r 13 ≤-6 mm , the center thickness of the front and rear surfaces d 8 is 2.4≤ d 8≤3.0, D Refractive index under light n d8 1.5≤ n d8 ≤1.6, D Abbe number under light v d8 72≤ vd8 ≤78; the curvature radius of the front surface of the second biconcave negative lens r 13 -8 mm ≤ r 13 ≤-6 mm , back surface curvature radius r 14 36 mm ≤ r 14 ≤40 mm , the center thickness of the front and rear surfaces d 9 is 2.4≤ d 9≤3.0, D Refractive index under light n d9 1.7≤ n d9 ≤1.8, D Abbe number under light v d9 25≤ v d9 ≤30.

[0006] In the above solution, the meniscus positive lens, the first biconcave negative lens, the concave-convex positive lens, the first concave-convex negative lens, the second concave-convex negative lens, the first biconvex positive lens, the second biconvex positive lens, the third biconvex positive lens and the second biconcave negative lens are all glass lenses.

[0007] In the above solution, the protective glass is H - K 9. Flat glass.

[0008] Compared with the prior art, the present invention has the following characteristics:

[0009] (1) Realize the confocal design of visible light and near-infrared wide spectrum, with near-infrared focal shift of 9.86μ m , can be ignored.

[0010] (2) A new structural design is adopted to achieve 110° ultra-wide-angle imaging.

[0011] (3) The image space telecentric design is adopted to achieve a relative illumination of better than 98% across the entire field of view, providing uniform high brightness for security lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a design drawing of the ultra-wide-angle day and night confocal security lens of the present invention.

[0013] Figure 2 The ultra-wide-angle day and night confocal security lens of the present invention MTF curve chart.

[0014] Figure 3 This is a diagram of vertical axial chromatic aberration of the ultra-wide-angle day and night confocal security lens of the present invention.

[0015] Figure 4 This is a focus shift diagram of the ultra-wide-angle day and night confocal security lens of the present invention.

[0016] Figure 5 This is a relative illumination diagram of the ultra-wide-angle day and night confocal security lens of the present invention.

[0017] Markings in the figure: 1-meniscus positive lens, 2-first biconcave negative lens, 3-concave-convex positive lens, 4-first concave-convex negative lens, 5-second concave-convex negative lens, 6-first biconvex positive lens, 7-second biconvex positive lens, 8-third biconvex positive lens, 9-second biconcave negative lens, 10-flat protective glass.

[0018] Markings in the figure: 1-meniscus positive lens, 2-first biconcave negative lens, 3-concave-convex positive lens, 4-first concave-convex negative lens, 5-second concave-convex negative lens, 6-first biconvex positive lens, 7-second biconvex positive lens, 8-third biconvex positive lens, 9-second biconcave negative lens, 10-flat protective glass. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific examples.

[0020] In order to increase the imaging field of view of the day and night confocal security lens, reduce the use of aspheric surfaces, realize the wide spectrum day and night confocal design of visible light and near infrared, provide a security lens with high relative illumination, and meet the needs of actual use, the present invention proposes an ultra-wide-angle day and night confocal security lens, such as Figure 1 As shown, it consists of a meniscus positive lens 1, a first biconcave negative lens 2, a concave-convex positive lens 3, a first concave-convex negative lens 4, a second concave-convex negative lens 5, a first biconvex positive lens 6, a second biconvex positive lens 7, a third biconvex positive lens 8, a second biconcave negative lens 9, and a flat protective glass 10, which are arranged in sequence from front to back.

[0021] The meniscus positive lens 1 and the first biconcave negative lens 2 form a doublet lens. The curvature radius of the front surface of the meniscus positive lens 1 is r 1 is -22 mm ≤ r 1≤-18 mm , the radius of curvature of the rear surface r 2 is -17 mm ≤ r 2≤-14 mm , the center thickness of the front and rear surfaces d 1 is 2.6 mm ≤d 1≤3 mm , D Refractive index under light n d1 1.7≤ n d1 ≤1.8, D Abbe number under light v d1 50≤ v d1 ≤54. The curvature radius of the front surface of the first biconcave negative lens 2 r 2 is -17 mm ≤ r 2≤-14 mm , back surface curvature radius r 3 is 11 mm ≤ r 3≤14 mm , the center thickness of the front and rear surfaces d 2 is 0.5 mm ≤ d 2≤0.7 mm , D Refractive index under light n d2 1.4≤ n d2 ≤1.5, D Abbe number under light v d2 79≤ v d2 ≤82.

[0022] The concave-convex positive lens 3 and the first concave-convex negative lens 4 form a doublet lens. The curvature radius of the front surface of the concave-convex positive lens 3 is r 4 for 5 mm ≤ r 4≤7 mm , the radius of curvature of the rear surface r 5 for 7 mm ≤ r 5≤9 mm , the center thickness of the front and rear surfaces d 3 for 2 mm ≤ d 3≤3 mm , D Refractive index under light n d3 1.8≤ n d3 ≤1.9, D Abbe number under light v d3 30≤ v d3 ≤33. The curvature radius of the front surface of the first concave-convex negative lens 4 isr 5 for 7 mm ≤ r 5≤9 mm , back surface curvature radius r 6 for 2 mm ≤ r 6≤3 mm , the center thickness of the front and rear surfaces d 4 is 0.6 mm ≤ d 4≤0.8 mm , D Refractive index under light n d4 1.6≤ n d4 ≤1.7, D Abbe number under light v d4 42≤ v d4 ≤46.

[0023] The second concave-convex negative lens 5 and the first biconvex positive lens 6 form a doublet lens. The curvature radius of the front surface of the second concave-convex negative lens 5 is r 7 is 20 mm ≤ r 7≤23 mm , the radius of curvature of the rear surface r 8 to 6 mm ≤ r 8≤8 mm , the center thickness of the front and rear surfaces d 5 for 2.7 mm ≤ d 5≤3 mm , D Refractive index under light n d5 1.7≤ n d5 ≤1.8, D Abbe number under light v d5 50≤ v d5 ≤54. The curvature radius of the front surface of the first biconvex positive lens 6 is r 8 to 6 mm ≤ r 8≤8 mm , back surface curvature radius r 9 is -5 mm ≤ r 9≤-3 mm , the center thickness of the front and rear surfaces d 6 for 2.3 mm ≤ d 6≤2.6 mm ,D Refractive index under light n d6 1.4≤ n d6 ≤1.6, D Abbe number under light v d6 82≤ v d6 ≤85.

[0024] The second biconvex positive lens 7 is a single lens, and the curvature radius of the front surface is r 10 is 9 mm ≤ r 10 ≤11 mm , the curvature radius of the back r 11 -9 mm ≤ r 11 ≤-7 mm , the center thickness of the front and rear surfaces d 7 is 2.3 mm ≤ d 7≤2.7 mm , D Refractive index under light n d7 1.5≤ n d7 ≤1.6, D Abbe number under light v d7 72≤ v d7 <≤78.

[0025] The third biconvex positive lens 8 and the second biconcave negative lens 9 form a double cemented lens. The third biconvex positive lens 8 has a front surface curvature radius of r 12 is 10 mm ≤ r 12 ≤13 mm , the radius of curvature of the rear surface r 13 -8 mm ≤ r 13 ≤-6 mm , the center thickness of the front and rear surfaces d 8 is 2.4≤ d 8≤3.0, D Refractive index under light n d8 1.5≤ n d8 ≤1.6, DAbbe number under light v d8 72≤ v d8 ≤78. The curvature radius of the front surface of the second biconcave negative lens 9 is r 13 -8 mm ≤ r 13 ≤-6 mm , back surface curvature radius r 14 36 mm ≤ r 14 ≤40 mm , the center thickness of the front and rear surfaces d 9 is 2.4≤ d 9≤3.0, D Refractive index under light n d9 1.7≤ n d9 ≤1.8, D Abbe number under light v d9 25≤ v d9 ≤30.

[0026] Protective glass for H - K 9. Flat glass.

[0027] Can be matched with Omnivision company's OV 9285 image sensor with a pixel size of 3μ m ×3μ m , with a resolution of 1344×1136 and a main ray incident angle of less than 9°, achieving 1.52 million pixel imaging. The ultra-wide-angle wide-spectrum confocal security lens consists of 9 glass lenses and 1 flat protective glass 10. Through the diaphragm, the front group is a wide-angle objective lens composed of two double-cemented lenses, and the rear group is a wide-angle eyepiece composed of double-cemented lenses + single lens + double-cemented lenses. It uses a pure spherical design, and multiple cemented lenses adopt high refractive index and low dispersion. H - ZF 52 lens with low refractive index and high dispersion H - FK 61 to correction system 486 nm ~850 nm The final design achieves a system focal length of 3.86 mm ,system F Number 1.8, band 486 nm ~850 nmWide spectrum design, full field of view 110°, image space telecentric design, full field of view relative illumination better than 98%, 850 nm Infrared focal shift 9.86μ m , total system length 25.9 mm The data table of ultra-wide-angle day and night confocal security lenses is shown in Table 1.

[0028] Table 1 Security lens data sheet

[0029] Serial number Surface type Radius of curvature / thickness / Refractive index Abbe number Physical Surface Standard surface unlimited unlimited 1 Standard surface -20.100 2.900 1.755 52.337 2 Standard surface -15.543 0，621 1.497 81.595 3 Standard surface 12.640 0.177 4 Standard surface 6.078 2.899 1.850 32.308 5 Standard surface 7.556 0.784 1.613 44.339 6 Standard surface 2.319 2.139 aperture Standard surface 21.373 2.981 1.755 52.337 8 Standard surface 6.439 2.568 1.486 84.474 9 Standard surface -4.310 0.034 10 Standard surface 9.177 2.586 1.528 76.976 11 Standard surface -8.814 0.132 12 Standard surface 10.231 2.712 1.528 76.976 13 Standard surface -6.116 2.767 1.717 29.51 14 Standard surface 38.684 1.828 15 Standard surface unlimited 0.400 1.516 64.212 16 Standard surface unlimited 0.430 Image plane Standard surface unlimited

[0030] Figure 2 For ultra-wide-angle day and night confocal security lenses MTF As can be seen from the curve, at the 1 / 2 cutoff frequency, the central field modulation transfer function is higher than 64%, and the field modulation transfer function within 0.7 is higher than 42%. lp / mm The modulation transfer function of the entire field of view is better than 20%, and the day and night confocal security lens optical system has excellent image quality.

[0031] Figure 3 This is the vertical axis chromatic aberration diagram of the ultra-wide-angle day and night confocal security lens. As can be seen from the figure, the maximum vertical axis chromatic aberration from visible light to 850nm near-infrared light is 6μ m About 100 nm, which is comparable to the Airy disk (double dashed line in the figure).

[0032] Figure 4 This is the focal shift diagram of the ultra-wide-angle day and night confocal security lens. As can be seen from the figure, the maximum focal shift relative to the main wavelength in the entire band is 9.86μ m , infrared focal shift can be ignored.

[0033] Figure 5 This is the relative illumination diagram of the ultra-wide-angle day and night confocal security lens. As can be seen from the figure, the illumination ratio of each field of view relative to the illumination of the 0° field of view, the relative illumination of the entire field of view is better than 98%, providing a uniform high-brightness security lens.

[0034] It should be noted that although the embodiments of the present invention described above are illustrative, they are not intended to limit the present invention. Therefore, the present invention is not limited to the above-mentioned specific embodiments. Without departing from the principles of the present invention, any other embodiments obtained by those skilled in the art under the guidance of the present invention are deemed to be within the protection of the present invention.

Claims

1. Ultra-wide-angle day and night confocal security lens, its characteristics are: The invention is composed of a meniscus positive lens (1), a first biconcave negative lens (2), a concave-convex positive lens (3), a first concave-convex negative lens (4), a second concave-convex negative lens (5), a first biconvex positive lens (6), a second biconvex positive lens (7), a third biconvex positive lens (8), a second biconcave negative lens (9), and a flat protective glass (10) which are arranged in sequence from front to back; the meniscus positive lens (1), the first biconcave negative lens (2), the concave-convex positive lens (3), the first concave-convex negative lens (4), the second concave-convex negative lens (5), the first biconvex positive lens (6), the second biconvex positive lens (7), the third biconvex positive lens (8), and the second biconcave negative lens (9) are all glass lenses; the protective glass is H - K 9. Plate glass; The meniscus positive lens (1) and the first biconcave negative lens (2) form a double cemented lens; the meniscus positive lens (1) has a front surface curvature radius of r 1 is -22 mm ≤ r 1≤-18 mm , the radius of curvature of the rear surface r 2 is -17 mm ≤ r 2≤-14 mm , the center thickness of the front and rear surfaces d 1 is 2.6 mm ≤ d 1≤3 mm , D Refractive index under light n d1 1.7≤ n d1 ≤1.8, D Abbe number under light v d1 50≤ v d1 ≤54; the first biconcave negative lens (2), the radius of curvature of the front surface r 2 is -17 mm ≤ r 2≤-14 mm , back surface curvature radius r 3 is 11 mm ≤ r 3≤14 mm , the center thickness of the front and rear surfaces d 2 is 0.5 mm ≤ d 2≤0.7 mm , D Refractive index under light n d2 1.4≤ n d2 ≤1.5, D Abbe number under light v d2 79≤ v d2 ≤82; The concave-convex positive lens (3) and the first concave-convex negative lens (4) form a doublet lens; the concave-convex positive lens (3) has a front surface curvature radius of r 4 for 5 mm ≤ r 4≤7 mm , the radius of curvature of the rear surface r 5 for 7 mm ≤ r 5≤9 mm , the center thickness of the front and rear surfaces d 3 for 2 mm ≤ d 3≤3 mm , D Refractive index under light n d3 1.8≤ n d3 ≤1.9, D Abbe number under light v d3 30≤ v d3 ≤33; the first concave-convex negative lens (4), the curvature radius of the front surface r 5 for 7 mm ≤ r 5≤9 mm , back surface curvature radius r 6 for 2 mm ≤ r 6≤3 mm , the center thickness of the front and rear surfaces d 4 is 0.6 mm ≤ d 4≤0.8 mm , D Refractive index under light n d4 1.6≤ n d4 ≤1.7, D Abbe number under light v d4 42≤ v d4 ≤46; The second concave-convex negative lens (5) and the first biconvex positive lens (6) form a double cemented lens; the curvature radius of the front surface of the second concave-convex negative lens (5) is r 7 is 20 mm ≤ r 7≤23 mm , the radius of curvature of the rear surface r 8 to 6 mm ≤ r 8≤8 mm , the center thickness of the front and rear surfaces d 5 for 2.7 mm ≤ d 5≤3 mm , D Refractive index under light n d5 1.7≤ n d5 ≤1.8, D Abbe number under light v d5 50≤ v d5 ≤54; the first biconvex positive lens (6), the radius of curvature of the front surface r 8 to 6 mm ≤ r 8≤8 mm , back surface curvature radius r 9 is -5 mm ≤ r 9≤-3 mm , the center thickness of the front and rear surfaces d 6 for 2.3 mm ≤ d 6≤2.6 mm , D Refractive index under light n d6 1.4≤ n d6 ≤1.6, D Abbe number under light v d6 82≤ v d6 ≤85; The second biconvex positive lens (7) is a single lens, and the curvature radius of the front surface is r 10 is 9 mm ≤ r 10 ≤11 mm , the curvature radius of the back r 11 -9 mm ≤ r 11 ≤-7 mm , the center thickness of the front and rear surfaces d 7 is 2.3 mm ≤ d 7≤2.7 mm , D Refractive index under light n d7 1.5≤ n d7 ≤1.6, D Abbe number under light v d7 72≤ v d7 <≤78; The third biconvex positive lens (8) and the second biconcave negative lens (9) form a double cemented lens; the third biconvex positive lens (8) has a front surface curvature radius of r 12 is 10 mm ≤ r 12 ≤13 mm , the radius of curvature of the rear surface r 13 -8 mm ≤ r 13 ≤-6 mm , the center thickness of the front and rear surfaces d 8 is 2.4≤ d 8≤3.0, D Refractive index under light n d8 1.5≤ n d8 ≤1.6, D Abbe number under light v d8 72≤ v d8 ≤78; the curvature radius of the front surface of the second biconcave negative lens (9) r 13 -8 mm ≤ r 13 ≤-6 mm , back surface curvature radius r 14 36 mm ≤ r 14 ≤40 mm , the center thickness of the front and rear surfaces d 9 is 2.4≤ d 9≤3.0, D Refractive index under light n d9 1.7≤ n d9 ≤1.8, D Abbe number under light v d9 25≤ v d9 ≤30.

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