Low-illumination high-definition optical lens

Abstract

The present application relates to a kind of low-illuminance high-definition optical lens, the optical system of lens includes first lens, second lens, third lens, diaphragm, fourth lens, fifth lens and sixth lens in turn from left to right along the light path of light incidence, first lens is meniscus negative lens, second lens is meniscus negative lens, third lens is double-convex positive lens, fourth lens is meniscus negative lens, fifth lens is double-convex positive lens, and sixth lens is meniscus positive lens, fourth lens and fifth lens are cemented lens group, first lens, fourth lens and fifth lens are all glass spherical lens, and second lens, third lens, sixth lens are all glass aspherical lens.The optical structure of the present application is combined with three glass spherical lenses and three glass aspherical lenses, has higher light transmission capacity, while ensuring that optical system has larger relative aperture, has more than 80% relative luminance, so that optical system can still high-definition imaging in low-illuminance environment.

Description

TECHNICAL FIELD

[0001] The application relates to a low-illumination high-definition optical lens. BACKGROUND

[0002] With the development of high definition, networking and intelligence of security monitoring, the application range of monitoring camera lenses is more and more extensive, and many places with poor monitoring conditions and dim light also require the installation of monitoring camera lenses with multiple functions, especially low-illumination high-definition camera lenses, to meet the demand of all-weather 24-hour monitoring. In a low-illumination environment such as night, if the light quantity of the camera lens is not enough, the picture will be dark, affecting the definition. Therefore, it is necessary to design a low-illumination high-definition optical lens. SUMMARY

[0003] The application improves the prior art, and the technical problem to be solved by the application is to provide a low-illumination high-definition optical lens.

[0004] In order to achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows: a low-illumination high-definition optical lens, the optical system of the lens comprises, from left to right along the light incident path, a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens and a sixth lens, the first lens is a meniscus negative lens, the second lens is a meniscus negative lens, the third lens is a double-convex positive lens, the fourth lens is a meniscus negative lens, the fifth lens is a double-convex positive lens, and the sixth lens is a meniscus positive lens, the fourth lens and the fifth lens are a cemented lens group, the first lens, the fourth lens and the fifth lens are glass spherical lenses, and the second lens, the third lens and the sixth lens are glass aspherical lenses.

[0005] Further, the air gap between the first lens and the second lens is 4.85-5.51mm, the air gap between the second lens and the third lens is 0.08-0.17mm, the air gap between the third lens and the fourth lens is 0.5-1.5mm, and the air gap between the fifth lens and the sixth lens is 0.07-0.15mm.

[0006] Further, the focal length of the optical system is f, and 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, wherein f1, f2, f3, f4, f5 and f6 and f satisfy the following ratios: -2.5

[0007] Further, the first lens satisfies the relationship: N d ≥ 1.5, V d ≤ 50.0; the second lens satisfies the relationship: N d ≥ 1.5, V d ≤ 50.0; the third lens satisfies the relationship: N d ≥ 1.5, V d ≤ 50.0; the fourth lens satisfies the relationship: N d ≥ 1.5, V d ≤ 50.0; the fifth lens satisfies the relationship: N d ≥ 1.5, V d ≥ 50.0; the sixth lens satisfies the relationship: N d ≥ 1.5, V d ≥ 50.0; wherein N d is the refractive index, and V d is the Abbe number.

[0008] Further, the optical total length TTL of the optical system satisfies: TTL / f≤8.0, wherein f is the focal length of the optical system.

[0009] Further, the F number of the optical system is ≤1.4.

[0010] Further, the image height H of the optical system satisfies: H / f≥2.0, wherein f is the focal length of the optical system.

[0011] Further, the aspheric surface curve equation expression of the second lens, the third lens and the sixth lens is:

[0012]

[0013] wherein Z is the sagittal height of the aspheric surface at a height of h along the optical axis direction from the vertex of the aspheric surface; c is the paraxial curvature of the aspheric surface; k is the conic constant; α1, α2, α3, α4, α5, α6, α7 and α8 are high-order coefficients.

[0014] Compared with the prior art, the present application has the following effects: the present application adopts the optical structure of the combination of three glass spherical lenses and three glass aspheric lenses, has a smaller size compared with the traditional lens, and simultaneously the optical imaging quality reaches high-definition clarity; simultaneously, the six optical lenses are all made of glass materials, have high light transmission capacity, guarantee a large relative aperture of the optical system, and have a relative luminance of more than 80%, so that the optical system can still perform high-definition imaging in a low-illumination environment. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is the optical structure schematic diagram of the embodiment of the present application;

[0016] Figure 2 This is an axial chromatic aberration diagram of the entire working band of this invention.

[0017] Figure 3 This is a cross-axis chromatic aberration diagram of the entire working band of this invention.

[0018] Figure 4 This is a field curvature distortion diagram of the entire working band of this invention embodiment;

[0019] Figure 5 This is a full-field relative illumination map according to an embodiment of the present invention.

[0020] In the picture:

[0021] L1 - First lens; L2 - Second lens; L3 - Third lens; STO - Aperture stop; L4 - Fourth lens; L5 - Fifth lens; L6 - Sixth lens; L7 - Equivalent glass plate; IMA - Imaging surface. Detailed implementation method:

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1 As shown, the present invention discloses a low-light high-definition optical lens. The optical system of the lens includes a first lens L1, a second lens L2, a third lens L3, an aperture stop STO, a fourth lens L4, a fifth lens L5, and a sixth lens L6 arranged sequentially from left to right along the incident light path. The first lens L1 is a meniscus negative lens, the second lens L2 is a meniscus negative lens, the third lens L3 is a biconvex positive lens, the fourth lens L4 is a meniscus negative lens, the fifth lens L5 is a biconvex positive lens, and the sixth lens L6 is a meniscus positive lens. The fourth lens L4 and the fifth lens L5 are a cemented lens group. Lens L1, L2, L3, stop STO, L4, L5, and L6 are all made of glass. Lens L1, L4, and L5 are spherical glass lenses, while L2, L3, and L4 are aspherical glass lenses. The optical structure uses a combination of three spherical and three aspherical glass lenses, i.e., a 3G3MG optical structure. Figures 2 to 5 As shown, the optical system in this embodiment has effectively corrected on-axis and off-axis aberrations, while ensuring that the optical system has a relative illumination of more than 80%.

[0024] In the embodiment, the air gap between the first lens L1 and the second lens L2 is 4.85-5.51 mm; the air gap between the second lens L2 and the third lens L3 is 0.08-0.17 mm; the air gap between the third lens L3 and the fourth lens L4 is 0.5-1.5 mm; and the air gap between the fifth lens L5 and the sixth lens L6 is 0.07-0.15 mm.

[0025] In the embodiment, the focal length of the optical system is f, and the focal lengths of the first lens L2, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are f1, f2, f3, f4, f5 and f6 respectively, wherein f1, f2, f3, f4, f5 and f6 satisfy the following ratios: -2.5

[0026] In the embodiment, the first lens L1 satisfies the relationship: N d ≥ 1.5, and V d ≤ 50.0; the second lens L2 satisfies the relationship: N d ≥ 1.5, and V d ≤ 50.0; the third lens L3 satisfies the relationship: N d ≥ 1.5, and V d ≤ 50.0; the fourth lens L4 satisfies the relationship: N d ≥ 1.5, and V d ≥ 50.0; the fifth lens L5 satisfies the relationship: N d ≥ 1.5, and V d ≥ 50.0; and the sixth lens L6 satisfies the relationship: N d ≥ 1.5, and V d ≥ 50.0; wherein N d is the refractive index, and V d is the Abbe number.

[0027] In the embodiment, the total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤8.0.

[0028] In the embodiment, the F number of the optical system is ≤1.4.

[0029] In the embodiment, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≥2.0.

[0030] In the embodiment, the aspherical surface curve equation expression of the second lens L2, the third lens L3 and the sixth lens L6 is:

[0031]

[0032] Wherein, Z is the sagittal height of the aspherical surface at a position with a height of h along the optical axis from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface; k is the conic constant; and alpha1, alpha2, alpha3, alpha4, alpha5, alpha6, alpha7 and alpha8 are high-order coefficients.

[0033] In this embodiment, the aspherical surface coefficients of each aspherical lens of the optical system are as follows:

[0034]

[0035] In this embodiment, the technical indexes realized by the optical system are as follows:

[0036] (1) focal length: 3.0≤EFFL≤5.0mm; (2) aperture F≤1.4; (3) field of view angle: 2w≥120°; (4) working waveband: visible light waveband.

[0037] To realize the above technical indexes, the specific design of the optical system in this embodiment is shown in the following table:

[0038]

[0039]

[0040] The optical system in this embodiment has good correction on on-axis and off-axis aberrations, realizes the design of low-illumination high-definition imaging, and has the optical performances of large target surface, large aperture, low temperature drift, etc.

[0041] The advantages of the present application are:

[0042] (1) three glass spherical lenses and three glass aspherical lenses are combined, i.e., the optical structure of 3G3MG is adopted, wherein the third, fourth and sixth lenses are aspherical glass lenses, compared with the traditional lens, the size is smaller, and the optical imaging quality reaches high-definition clarity;

[0043] (2) the problem of small target surface is solved, the advantages of aspherical lenses are fully utilized, and an 8MP, 1 / 2 inch chip can be matched while other performances of the optical system are ensured;

[0044] (3) the six optical lenses adopted in the present application are all made of glass material, have high light transmission capacity, have a relative aperture of more than 80% while ensuring that the optical system has a large relative aperture, so that the optical system can still image in high definition under low-illumination environment;

[0045] (4) The application also has good high and low temperature performance, low lens tolerance sensitivity, small distortion, good illumination uniformity and the like; and can be used with a chip with a larger target surface while meeting the requirements of imaging quality, environmental adaptability and the like.

[0046] If the application discloses or involves mutually fixed connecting parts or structural parts, unless otherwise stated, the fixed connection can be understood as: detachable fixed connection (for example, using bolt or screw connection), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, integrally formed by using casting process) (except for obviously unable to use integral forming process).

[0047] In addition, the terms used to represent the positional relationship or shape in any of the technical solutions disclosed in the application include states or shapes similar, similar or close to them, unless otherwise stated.

[0048] Any component provided by the application can be assembled from multiple individual components, or can be a single component manufactured by integral forming process.

[0049] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the application and not to limit them; although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: the specific embodiments of the application can be modified or some technical features can be replaced by equivalents; without departing from the spirit of the technical solutions of the application, they should be covered in the technical solution range of the application claimed by the application.

Claims

1. A low-light high-definition optical lens, characterized in that: The optical system of the lens consists of a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, and a sixth lens arranged sequentially from left to right along the incident light path. The first lens is a meniscus negative lens, the second lens is a meniscus negative lens, the third lens is a biconvex positive lens, the fourth lens is a meniscus negative lens, the fifth lens is a biconvex positive lens, and the sixth lens is a meniscus positive lens. The fourth and fifth lenses are a cemented lens group. The first, fourth, and fifth lenses are all glass spherical lenses, and the second, third, and sixth lenses are all glass aspherical lenses. The air gap between the first and second lenses is 4.85~5.51mm; the air gap between the second and third lenses is 0.08~0.17mm; the air gap between the third and fourth lenses is 0.5~1.5mm; and the air gap between the fifth and sixth lenses is 0.07~0.15mm.

2. The low-light high-definition optical lens according to claim 1, characterized in that: The focal length of the optical system is f. The focal lengths of the first lens, second lens, third lens, fourth lens, fifth lens, and sixth lens are f1, f2, f3, f4, f5, and f6, respectively. The following ratios are satisfied between f1, f2, f3, f4, f5, f6 and f: -2.5 < f1 / f < -0.5, -15.0 < f2 / f < -14.0, 1.5 < f3 / f < 3.5, -2.5 < f4 / f < -0.5, 0.5 < f5 / f < 2.5, and 52.0 < f6 / f < 53.

0.

3. The low-light high-definition optical lens according to claim 1, characterized in that: The first lens satisfies the following relationship: N d ≥1.5, V d ≤50.0; The second lens satisfies the following relationship: N d ≥1.5, V d ≤50.0; The third lens satisfies the following relationship: N d ≥1.5, V d ≤50.0; The fourth lens satisfies the following relationship: N d ≥1.5, V d ≤50.0; The fifth lens satisfies the following relationship: N d ≥1.5, V d ≥50.0; The sixth lens satisfies the following relationship: N d ≥1.5, V d ≥50.0; where N d V is the refractive index. d Let be Abbe's constant.

4. A low-light high-definition optical lens according to claim 1, characterized in that: The total optical length (TTL) of an optical system and the focal length (f) of the optical system satisfy the following condition: TTL / f ≤ 8.

0.

5. A low-light high-definition optical lens according to claim 1, characterized in that: The F-number of the optical system is ≤1.

4.

6. A low-light high-definition optical lens according to claim 1, characterized in that: The image height H of the optical system and the focal length f of the optical system satisfy the following condition: H / f≥2.

0.

7. A low-light high-definition optical lens according to claim 1, characterized in that: The equations for the aspherical curves of the second, third, and sixth lenses are as follows: Where Z is the distance from the vertex of the aspherical surface to the optical axis at a height of h; c is the paraxial curvature of the aspherical surface; k is the conic constant; and α1, α2, α3, α4, α5, α6, α7, and α8 are all higher-order coefficients.

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