A day and night confocal 2 million pixel ultra-wide-angle fixed-focus optical lens

Abstract

The present invention discloses a day and night confocal 2 million pixel ultra-wide angle fixed focus optical lens, which includes: a first lens element, a second lens element, an aperture, a third lens element, and a fourth lens element from the object side to the image side; the first lens element is a meniscus lens with negative focal length convex to the object side; the second lens element is a biconvex lens with positive focal length; the third lens element is a biconvex lens with positive focal length; the fourth lens element is a biconcave lens with negative focal length. The present invention corrects off-axis aberrations and compensates for chromatic aberrations through the optimal optical design, obtains a larger aperture, and reduces aberrations such as spherical aberration, coma, and distortion, allows the lens to enter more light, allows the module chip to receive more image information and obtain a good imaging effect, and improves the performance quality of the corresponding optical system; reduces aberrations such as spherical aberration, coma, and distortion, and improves optical quality and MTF.

Description

Technical Field

[0001] The present invention relates to the field of lens technology, and more particularly to a day-and-night confocal 2-megapixel ultra-wide-angle fixed-focus optical lens. Background Art

[0002] With the booming development of the smart home field, the continuous improvement of the whole house intelligence and home security awareness, home security is becoming an increasingly rising part of smart home products, including home cameras, smart door locks, smart cat eyes, smart doorbells, infrared alarms, etc. According to relevant statistics, home security equipment will create a market worth 47 billion US dollars in 2020, which will also be a market that cannot be underestimated in the field of smart home; the core component of home security equipment is the optical lens, and the requirements of high pixel, large aperture, small distortion, high cost performance and stability have become the mainstream development trend. In order to meet the trend requirements, how to provide a day and night confocal 2 million pixel ultra-wide angle fixed focus optical lens is a problem that technicians in this field urgently need to solve. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a 2-megapixel ultra-wide-angle fixed-focus optical lens that provides day and night confocality, which has the characteristics of ultra-wide angle, large aperture, high cost performance, good stability, etc.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A day and night confocal 2 million pixel ultra-wide angle fixed focus optical lens, the lens comprises from the object side to the image side: a first lens element, a second lens element, an aperture, a third lens element, and a fourth lens element; characterized in that:

[0006] The first lens element is a meniscus lens with negative optical power convex to the object side;

[0007] The second lens element is a biconvex lens having positive optical power;

[0008] The third lens element is a biconvex lens with positive optical power;

[0009] The fourth lens element is a biconcave lens with negative optical power;

[0010] The first lens is a glass spherical lens; the second lens element, the third lens element and the fourth lens element are plastic aspherical lenses.

[0011] Preferably, in the above-mentioned day and night confocal 2-megapixel ultra-wide-angle fixed-focus optical lens, the first lens element satisfies: 1.73≤Nd1≤1.80; 52.35≤Vd1≤52.25; the second lens element satisfies: 1.52≤Nd2≤1.56; 55.4≤Vd2≤56.0; the third lens element satisfies: 1.50≤Nd3≤1.55; 55.70≤Vd3≤55.82; the fourth lens element satisfies: 1.60≤Nd4≤1.68; 23.48≤Vd4≤23.58.

[0012] Preferably, in the above-mentioned day and night confocal 2-megapixel ultra-wide-angle fixed-focus optical lens, the lens meets the following conditions: focal length meets: EFL ≥ 2.95 mm; total lens length meets: TTL ≤ 22.5 mm; lens aperture number meets: F / NO ≤ 1.8; lens field of view angle meets: DFOV ≥ 158°; lens image height meets: ≤ 7.0 mm; lens brightness meets: ≥ 46%; lens TV distortion meets: ≤ 38%; lens CRA meets: < 24%.

[0013] It can be seen from the above technical solution that compared with the prior art, the present invention corrects off-axis aberrations and compensates for chromatic aberrations through the optimal optical design, thereby obtaining a larger aperture, and reducing aberrations such as spherical aberration, coma, and distortion. The lens allows more light to enter, so that the module chip receives more image information and obtains a good imaging effect, and the performance quality of the corresponding optical system is improved; aberrations such as spherical aberration, coma, and distortion are reduced, and the optical quality and MTF are better; in addition, the present invention adopts an optical structure of 1 glass spherical lens plus 3 plastic aspherical lenses. The glass spherical lens has the advantage of simple processing, and the plastic aspherical lens has high performance. The present invention adopts a glass-plastic mixed structure so that the lens of the present invention has the characteristics of high performance, low cost, and light weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0015] Figure 1 The accompanying drawing is a schematic structural diagram of the present invention.

[0016] Figure 2 The accompanying drawing is a light path diagram of the present invention.

[0017] Figure 3 The accompanying drawing is a diagram showing the imaging principle of the present invention.

[0018] Figure 4 The accompanying drawing is a light fan diagram of the present invention.

[0019] Figure 5 The attached drawings are field curvature and distortion curve diagrams of the present invention.

[0020] Figure 6 The accompanying drawing is a MTF resolution curve diagram of the present invention.

[0021] Figure 7 The accompanying drawing is a point diagram of the present invention.

[0022] Figure 8 The accompanying drawing is a relative brightness curve diagram of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Please see attached Figure 1 , is a day and night confocal 2 million pixel ultra-wide-angle fixed-focus optical lens disclosed in the present invention, which includes, from the object side to the image side, a first lens element 1, a second lens element 2, an aperture 3, a third lens element 4, and a fourth lens element 5; wherein,

[0025] The first lens element is a meniscus lens with negative optical power convex to the object side;

[0026] The second lens element is a biconvex lens having positive optical power;

[0027] The third lens element is a biconvex lens with positive optical power;

[0028] The fourth lens element is a biconcave lens having negative optical power;

[0029] The first lens is a glass spherical lens; the second lens element, the third lens element and the fourth lens element are plastic aspherical lenses.

[0030] In order to further optimize the above technical solution, the first lens element satisfies: 1.73≤Nd1≤1.80; 52.35≤Vd1≤52.25; the second lens element satisfies: 1.52≤Nd2≤1.56; 55.4≤Vd2≤56.0; the third lens element satisfies: 1.50≤Nd3≤1.55; 55.70≤Vd3≤55.82; the fourth lens element satisfies: 1.60≤Nd4≤1.68; 23.48≤Vd4≤23.58.

[0031] In order to further optimize the above technical solution, the lens meets the following conditions: focal length meets: EFL ≥ 2.95mm; total lens length meets: TTL ≤ 22.5mm; lens aperture number meets: F / NO ≤ 1.8; lens field of view angle meets: DFOV ≥ 158°; lens image height meets: ≤ 7.0mm; lens brightness meets: ≥ 46%; lens TV distortion meets: ≤ 38%; lens CRA meets: < 24%.

[0032] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0033] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A day and night confocal 2 million pixel ultra-wide angle fixed focus optical lens, which includes from the object side to the image side: A first lens element, a second lens element, an aperture, a third lens element, and a fourth lens element; characterized in that: The first lens element is a meniscus lens with negative optical power convex to the object side; The second lens element is a biconvex lens having positive optical power; The third lens element is a biconvex lens with positive optical power; The fourth lens element is a biconcave lens with negative optical power; The fixed-focus optical lens has only the above four lenses as the components with optical refractive power; The first lens element is a glass spherical mirror; the second lens element, the third lens element and the fourth lens element are plastic aspherical mirrors; the first lens element satisfies: 1.73≤Nd1≤1.80; 52.25≤Vd1≤52.35; the second lens element satisfies: 1.52≤Nd2≤1.56; 55.4≤Vd2≤56.0; the third lens element satisfies: 1.50≤Nd3≤1.55; 55.70≤Vd3≤55.8 2; the fourth lens element satisfies: 1.60≤Nd4≤1.68; 23.48≤Vd4≤23.58; the lens satisfies the following conditions: the focal length satisfies: EFL≥2.95mm; the total length of the lens satisfies: TTL≤22.5mm; the lens aperture number satisfies: F / NO≤1.8; the lens field of view angle satisfies: DFOV≥158°; the lens image height satisfies: ≤7.0mm; the lens brightness satisfies: ≥46%; the lens TV distortion satisfies: ≤38%.

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