Large-aperture lens

Abstract

The utility model belongs to the technical field of optical imaging systems, and particularly relates to a large-aperture lens. The optical system comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and an imaging surface which are sequentially arranged from an object side to an image side. The first lens has negative focal power, and the object side surface and the image side surface are concave surfaces; the second lens has positive focal power, and the object side surface and the image side surface are convex surfaces; the third lens has positive focal power, the object side surface is a concave surface, and the image side surface is a convex surface; the fourth lens has positive focal power, and the object side surface and the image side surface are convex surfaces; the fifth lens has negative focal power, the object side surface is a concave surface, and the image side surface is a convex surface; the sixth lens has positive focal power, and the object side surface and the image side surface are convex surfaces. Wherein the fourth lens and the fifth lens are bonded to form a bonding lens. According to the utility model, the design of the six glass spherical lenses is adopted, and the large-aperture lens with a large angle, a large target surface and high definition is realized through reasonable distribution of focal power. Clear photos can be shot under a low light condition. The lens can be widely applied to the field of imaging lenses such as vehicle-mounted lenses and monitoring lenses.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical imaging systems, and particularly relates to a large-aperture lens. Background Art

[0002] In recent years, with the rapid development of optoelectronic technology, more and more scenes need to be photographed, so the requirements for optical lenses are getting higher and higher. Especially in low-light environments, it is required to increase the light input to improve the clarity of the image plane. In order to meet higher pixel requirements and powerful low-light imaging effects, imaging lenses with larger apertures and higher resolutions have become a new research hotspot. Content of the Utility Model

[0003] To solve the defects and deficiencies of the prior art; the purpose of the utility model is to provide a large-aperture lens with a simple structure, reasonable design, high resolution and large target surface. It adopts a design of six glass spherical lenses, with a simple structure, easy processing, low cost, and can work normally at -40°C to +85°C, can adapt to different environments, and has high overall reliability.

[0004] To achieve the above purpose, the technical solution adopted by the utility model is: it includes a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, and an imaging surface; the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens, and the imaging surface are arranged in sequence from the object side to the image side. The first lens has a negative optical power, and both the object side and the image side are concave surfaces; the second lens has a positive optical power, and both the object side and the image side are convex surfaces; the third lens has a positive optical power, the object side is a concave surface, and the image side is a convex surface; the fourth lens has a positive optical power, and both the object side and the image side are convex surfaces; the fifth lens has a negative optical power, the object side is a concave surface, and the image side is a convex surface; the sixth lens has a positive optical power, and both the object side and the image side are convex surfaces. Among them, the fourth lens and the fifth lens are bonded into a cemented lens.

[0005] Preferably, the first lens also satisfies: N1≥1.83, V1≤42.98, where N1 is the refractive index of the first lens and V1 is the Abbe number of the first lens;

[0006] The second lens also satisfies: N2≥1.78, V2≤25.75, where N2 is the refractive index of the second lens and V2 is the Abbe number of the second lens;

[0007] The third lens also satisfies: N3≥1.78, V3≤44.18, where N3 is the refractive index of the third lens and V3 is the Abbe number of the third lens;

[0008] The fourth lens also satisfies: N4≥1.62, V4≤60.11, where N4 is the refractive index of the fourth lens and V4 is the Abbe number of the fourth lens.

[0009] The fifth lens further satisfies: N5≥1.74, V5≤28.19, where N5 is the refractive index of the fifth lens and V5 is the Abbe number of the fifth lens.

[0010] The sixth lens further satisfies: N6≥1.51, V6≤65.05, where N6 is the refractive index of the fifth lens and V6 is the Abbe number of the fifth lens.

[0011] Preferably, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are all spherical lenses made of glass.

[0012] Preferably, the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are f1, f2, f3, f4, f5, and f6 respectively, and the focal length of the overall optical system is f, which satisfies the following: -4.1 < f1 < -3.9, 9.5 < f2 < 9.7, 17.4 < f3 < 17.5, 45.5 < f4 < 45.7, -30.5 < f5 < -30.3, 12 < f6 < 12.2, 3.8 < f < 3.9.

[0013] Preferably, the optical system aperture stop is located between the third lens and the fourth lens.

[0014] After adopting the above structure, the beneficial effects of the present utility model are as follows:

[0015] 1. Adopting a design of six spherical lenses made of glass, it has a simple structure, is easy to process, has a low cost, can work normally from -40°C to +85°C, can adapt to different environments, and has high overall reliability.

[0016] 2. Through optimized design and reasonable distribution of the optical power, spherical aberration, coma, and astigmatism are effectively reduced, various aberrations are balanced, and the overall quality of the lens is improved.

[0017] 3. It can be matched with a 1 / 2.7" CCD photosensitive chip for use. When taking pictures in a low-light environment, it has a large aperture and a large amount of incident light, thereby improving the clarity of the image plane. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the present utility model will be described in detail by the following specific embodiments and the accompanying drawings.

[0019] Figure 1 is a schematic structural diagram of the present utility model;

[0020] Figure 2 is a modulation transfer function curve diagram of the present utility model;

[0021] Figure 3This is the field curvature distortion diagram of the present utility model;

[0022] Figure 4 This is the spot diagram of the present utility model.

[0023] Explanation of reference numerals: L1 - the first lens, L2 - the second lens, L3 - the third lens, L4 - the fourth lens, L5 - the fifth lens, L6 - the sixth lens, S - the aperture stop. Detailed implementation manners

[0024] To make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be described below through specific embodiments shown in the drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present utility model. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present utility model.

[0025] Here, it should also be noted that in order to avoid obscuring the present utility model due to unnecessary details, only the structures and / or processing steps closely related to the solution according to the present utility model are shown in the drawings, while other details less related to the present utility model are omitted.

[0026] Refer to as Figure 1 As shown, the following technical solutions are adopted in this detailed implementation manner: The optical system includes a first lens L1, a second lens L2, a third lens L3, an aperture stop S, a fourth lens L4, a fifth lens L5, a sixth lens L6, and an imaging surface, which are arranged in sequence from the object side to the image side; the first lens L1 has a negative optical power, and both the object side surface and the image side surface are concave surfaces; the second lens L2 has a positive optical power, and both the object side surface and the image side surface are convex surfaces; the third lens L3 has a positive optical power, the object side surface is a concave surface, and the image side surface is a convex surface; the fourth lens L4 has a positive optical power, and both the object side surface and the image side surface are convex surfaces; the fifth lens L5 has a negative optical power, the object side surface is a concave surface, and the image side surface is a convex surface; the sixth lens L6 has a positive optical power, and both the object side surface and the image side surface are convex surfaces. Among them, the fourth lens and the fifth lens are bonded into a cemented lens.

[0027] In this embodiment, the first lens further satisfies: N1≥1.83, V1≤42.98, where N1 is the refractive index of the first lens and V1 is the Abbe number of the first lens;

[0028] The second lens further satisfies: N2≥1.78, V2≤25.75, where N2 is the refractive index of the second lens and V2 is the Abbe number of the second lens;

[0029] The third lens further satisfies: N3≥1.78, V3≤44.18, where N3 is the refractive index of the third lens and V3 is the Abbe number of the third lens;

[0030] The fourth lens further satisfies: N4≥1.62, V4≤60.11, where N4 is the refractive index of the fourth lens and V4 is the Abbe number of the fourth lens;

[0031] The fifth lens further satisfies: N5≥1.74, V5≤28.19, where N5 is the refractive index of the fifth lens and V5 is the Abbe number of the fifth lens;

[0032] The sixth lens further satisfies: N6≥1.51, V6≤65.05, where N6 is the refractive index of the fifth lens and V6 is the Abbe number of the fifth lens.

[0033] In this embodiment, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are all spherical lenses made of glass.

[0034] In this embodiment, the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are f1, f2, f3, f4, f5, and f6 respectively, and the focal length of the overall optical system is f, which satisfies the following: -4.1 < f1 < -3.9, 9.5 < f2 < 9.7, 17.4 < f3 < 17.5, 45.5 < f4 < 45.7, -30.5 < f5 < -30.3, 12 < f6 < 12.2, 3.8 < f < 3.9.

[0035] In this embodiment, the optical system aperture stop is located between the third lens and the fourth lens.

[0036] In the embodiment of the present application, for the sake of convenience of description, the following expressions are made: the object surface is S0, the front surface of the first lens is S1, the rear surface of the first lens is S2, the front surface of the second lens is S3, the rear surface of the second lens is S4, the front surface of the third lens is S5, the rear surface of the third lens is S6, the aperture stop is S7, the front surface of the fourth lens is S8, the rear surface of the fourth lens and the front surface of the fifth lens are S9, the rear surface of the fifth lens is S10, the front surface of the sixth lens is S11, the rear surface of the sixth lens is S12, and the imaging surface is S13. The parameters of each lens are as follows in the table:

[0037]

[0038] In this embodiment, the optical lens achieves the following technical indicators:

[0039] EFL = 3.83mm, FOV = 125°, F / NO = 1.8, TOTR = 25mm, maximum image circle (IMA) = ∮6.6mm, relative illumination (RI) is greater than 80%, CRA < 16°.

[0040] By Figure 2It can be seen that the MTF of the optical lens in the visible light band is good. At the spatial frequency of 130 LP / MM in the central field of view, its MTF value is greater than 0.5; at the spatial frequency of 140 LP / MM in the marginal field of view, its MTF value is greater than 0.3. It can be seen that the curve drops gently and concentratedly, indicating that all performance of this optical lens is good.

[0041] It can be seen from Figure 3 that the optical lens effectively controls the field curvature for light rays of different wavelengths, that is, the image quality difference between the central and peripheral parts during imaging is small.

[0042] It can be seen from Figure 4 that the difference between the RMS radius value and the Airy disk radius value of the optical lens is small, indicating that its imaging quality is good and astigmatism and coma are effectively corrected.

[0043] The optical lens provided by the embodiment of the present application adopts a design of six spherical lenses made of glass material with a symmetric structure distribution. Its structure is simple, easy to process, and has a low cost, and can clearly image in a low-light environment.

[0044] For those skilled in the art, it is obvious that the present utility model is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present utility model. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present utility model.

[0045] In addition, it should be understood that although this specification is described according to embodiments, not each embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A large aperture lens, characterized in that: The lens comprises a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, a sixth lens and an imaging surface, which are arranged in sequence from the object side to the image side. The first lens has a negative focus, and both the object side and the image side are concave surfaces; the second lens has a positive focus, and both the object side and the image side are convex surfaces; the third lens has a positive focus, and the object side is concave and the image side is convex; the fourth lens has a positive focus, and both the object side and the image side are convex surfaces; the fifth lens has a negative focus, and the object side is concave and the image side is convex; the sixth lens has a positive focus, and both the object side and the image side are convex surfaces; wherein the fourth lens and the fifth lens are bonded to form a cemented lens.

2. A large aperture lens according to claim 1, characterized in that: The first lens further satisfies: N1≥1.83, V1≤42.98, wherein N1 is the refractive index of the first lens, and V1 is the Abbe number of the first lens; The second lens also satisfies: N2≥1.78, V2≤25.75, where N2 is the refractive index of the second lens, and V2 is the Abbe number of the second lens; The third lens further satisfies: N3≥1.78, V3≤44.18, wherein N3 is the refractive index of the third lens, and V3 is the Abbe number of the third lens; The fourth lens further satisfies: N4≥1.62, V4≤60.11, wherein N4 is the refractive index of the fourth lens, and V4 is the Abbe number of the fourth lens; The fifth lens further satisfies: N5≥1.74, V5≤28.19, wherein N5 is the refractive index of the fifth lens, and V5 is the Abbe number of the fifth lens; The sixth lens further satisfies: N6≥1.51, V6≤65.05, wherein N6 is the refractive index of the fifth lens, and V6 is the Abbe number of the fifth lens.

3. The large aperture lens according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all spherical lenses made of glass.

4. The large aperture lens according to claim 1, characterized in that: The focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are f1, f2, f3, f4, f5 and f6 respectively. The focal length of the overall optical system is f, which satisfies the following -4.1 <f1<-3.9、9.5<f2<9.7、17.4<f3<17.5、45.5<f4<45.7、-30.5<f5<-30.3、12<f6<12.2、3.8<f<3.9。 5. The large aperture lens according to claim 1, characterized in that: The optical system aperture is located between the third lens and the fourth lens.

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