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a lens

A lens, lens technology, applied in the field of lenses, can solve the problem of small aperture of the lens

Active Publication Date: 2021-04-16
ZHEJIANG DAHUA TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The embodiment of the present invention provides a lens to solve the problem of small lens aperture in the prior art

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0076] image 3 The schematic diagram of the lens structure provided by the embodiment of the present invention, the focal length of the lens is 12.58 mm, the aperture Fno is 1.20, and the total length TTL of the lens is about 99.8 mm.

[0077] The data such as the radius of curvature, central thickness, refractive index nd, and Abbe constant Vd of each lens are shown in Table 1:

[0078]

[0079]

[0080] Table 1

[0081] It should be noted that the face numbers in Table 1 are figure 1 In the schematic diagram of the lens structure shown, the surface numbers of the lenses are from left to right.

[0082] According to the data in Table 1 and related formulas, it can be obtained: f2=24.65mm; NL=13; |f2 / f system|=1.96; (TTL*Fno*Fno*NL*NL) / 20000=1.21; nd5=2.051 ;nd10=1.804; Vd3=61.25; Vd4=68.62; Vd6=68.62; Vd12=68.62.

[0083] The lens provided in the first embodiment will be further introduced below through a detailed optical system analysis of the first embodiment.

...

Embodiment 2

[0087] Figure 5 The schematic diagram of the lens structure provided by the embodiment of the present invention, the focal length of the lens is 12.13 mm, the aperture Fno is 1.02, and the total length TTL of the lens is 138 mm.

[0088] The data such as the radius of curvature, central thickness, refractive index nd, and Abbe constant Vd of each lens are shown in Table 2:

[0089]

[0090]

[0091] Table 2

[0092] According to the data in Table 2 and related formulas, it can be obtained: f2=21.65mm; NL=13; |f2 / f system|=1.78; (TTL*Fno*Fno*NL*NL) / 20000=1.21; nd5=2.003 ; nd10 = 1.804; Vd3 = 81.56; Vd4 = 68.35; Vd6 = 68.35; Vd12 = 68.35.

[0093]The lens provided by the second embodiment will be further introduced below by analyzing the optical system of the second embodiment in detail.

[0094] Figure 6 is the transfer function (MTF) curve, the curve is smoothly descending and concentrated. At 140lp / mm, the MTF value within the image height of 7.48mm is greater th...

Embodiment 3

[0096] Figure 7 It is a schematic diagram of the structure of the lens provided by the embodiment of the present invention. The focal length of the lens is 12.5 mm, the aperture Fno is 1.02, and the total length TTL of the lens is 118 mm.

[0097] The data such as the radius of curvature, central thickness, refractive index nd, and Abbe constant Vd of each lens are shown in Table 3:

[0098]

[0099]

[0100] table 3

[0101] According to the data in Table 3 and related formulas, it can be obtained: f2=21.99mm; NL=14; |f2 / f system|=1.76; (TTL*Fno*Fno*NL*NL) / 20000=1.20; nd5=1.923 ;nd10=2.003; Vd3=81.56; Vd4=68.62; Vd6=68.62; Vd12=68.62.

[0102] In the following, the lens provided in the third embodiment will be further introduced by analyzing the optical system of the third embodiment in detail.

[0103] Figure 8 is the transfer function (MTF) curve, the curve is smoothly descending and concentrated. At 140lp / mm, the MTF value within the image height of 7.48mm is ...

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Abstract

The invention discloses a lens, which comprises a first lens group, a second lens group and an imaging surface arranged in sequence from the object side to the image side; the lens group satisfies the following condition: 1.6<|f2 / fsystem|<2.0 ; 1.15<(TTL*Fno*Fno*NL*NL) / 20000<1.25; wherein, f2 is the focal length of the second lens group, f system is the system focal length of the lens, TTL is the total optical length of the lens, Fno is the aperture value of the lens, and NL is the number of lenses. Because in the embodiment of the present invention, two lens groups are arranged sequentially from the object side to the image side in the lens according to a specific order, and the lens groups in the lens satisfy: 1.6<|f2 / f system|<2.0; 1.15<( TTL*Fno*Fno*NL*NL) / 20000<1.25; therefore, the lens provided by the embodiment of the present invention has a large aperture and high resolution.

Description

technical field [0001] The invention relates to the technical field of optical imaging, in particular to a lens. Background technique [0002] Machine vision lenses are widely used in manufacturing, quality inspection, logistics, medicine, scientific research and other fields. At present, the actual aperture of common traffic lenses on the market is mostly F1.6 to 1.8. In low-light scenes, the imaging brightness is low, and the image noise is more, which affects the image clarity. In order to improve the brightness, a large amount of fill light is required, which also Make light pollution bigger. In addition, the resolution of a few lenses with large apertures on the market is relatively low, generally 5 million pixels, and the quality of the captured images is poor. With the advancement of security to high-definition, the lens needs to achieve higher performance. Therefore, it is particularly important to develop a lens with a large aperture and high resolution. Conten...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02B13/00G02B7/02G02B7/00
CPCG02B13/005G02B7/02G02B7/006
Inventor 林法官刘凯丁洪兴
Owner ZHEJIANG DAHUA TECH CO LTD
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