A large-aperture ultra-wide-angle high-definition lens and a camera device including the lens

Abstract

The invention discloses a large-aperture ultra-wide-angle high-definition lens and a camera device including the lens. The large-aperture ultra-wide-angle high-definition lens comprises, along the optical axis from the object plane to the image plane, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and a filter. The invention has a compact structure and a small size, and greatly reduces the weight of the lens, reduces the cost and speeds up the research and development cycle. The aberration of the lens system of the invention is corrected to a large extent, and the MTF resolution is high, ensuring high-definition and uniform imaging on the entire image plane, and can match a 1 / 2.5 chip (more than 8 million pixels). The field of view of the lens of the invention reaches more than 160 degrees, and the FNO. reaches 1.2, and the luminous flux is large and the night camera effect is better.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular to a large-aperture ultra-wide-angle high-definition lens and a camera device comprising the lens. Background Art

[0002] In the field of security, network cameras are commonly used equipment in security systems, and lenses are the main components of network cameras. Lens performance directly affects the image quality and imaging field of view. With the development of society, the requirements for the technical indicators of security monitoring lenses are constantly improving, especially the requirements for night imaging quality are getting higher and higher. The aperture of the existing ultra-wide-angle lens is generally around 2.0, and the field of view of the existing ultra-large aperture lens is generally below 100 degrees. In order to present a better effect in a dim environment, the aperture must be increased. However, the large aperture and ultra-wide angle bring a larger imaging field of view and more difficult to correct aberrations, making it difficult for large aperture lenses designed and manufactured with traditional structures to take into account a large field of view and generally have low resolution.

[0003] Chinese patent application number CN201611209922.9 discloses a large-aperture high-definition optical system, which is provided with: a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens in sequence along the optical axis from the object plane to the image plane; the object side of the first lens is convex, and the image side is concave; the second lens is a double concave lens; the third lens is a double convex lens; the object side of the fourth lens is concave, and the image side is convex; the object side of the fifth lens is concave, and the image side is convex; the sixth lens is a double convex lens; wherein the fourth lens and the fifth lens are combined lenses, and meet TTL / EFL≤5.5. On the other hand, an embodiment of the present invention also provides a lens. The embodiment of the present invention is mainly composed of six lenses, with a small number of lenses and a simple structure; different lenses are combined with each other, and the fourth lens and the fifth lens are cemented lenses, which have optical properties such as large aperture, high pixel, low distortion and good athermal difference.

[0004] However, the above wide-angle lens still has the following disadvantages:

[0005] 1. Small field of view (<100°);

[0006] 2. Small aperture (FNO=1.70), poor night photography effect;

[0007] 3.MTF resolution is low. Summary of the invention

[0008] The purpose of the present invention is to solve the deficiencies in the prior art and to provide a large-aperture ultra-wide-angle high-definition lens and a camera device including the lens.

[0009] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0010] A large-aperture ultra-wide-angle high-definition lens, which comprises, in order from the object plane to the image plane along the optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and a filter, wherein the first lens is a glass spherical lens with negative focal power, and the object side of the first lens is convex and the image side is concave, the second lens is a plastic aspherical lens with negative focal power, and the object side of the second lens is concave and the image side is concave; the third lens is a plastic aspherical lens with positive focal power, and the object side of the third lens is convex and the image side is concave; the fourth lens is a glass spherical lens with negative focal power, and the object side of the third lens is convex and the image side is concave; the fifth lens is a glass spherical lens with positive focal power, and the object side of the third lens is convex and the image side is concave; the sixth lens is a glass spherical lens with negative focal power, and the object side of the third lens is concave and the image side is concave; the sixth lens is a glass spherical lens with positive focal power, and the object side of the third lens is convex and the image side is concave; the sixth lens is a glass spherical lens with negative focal power, and the object side of the third lens is convex and the image side is concave; the seventh lens is a glass spherical lens with negative focal power, and the object side of the third lens is convex and the image side is concave; the seventh lens is a glass spherical lens with negative focal power, and the object side of the first ... The lens is a plastic aspheric lens with positive focal power, and the object side of the fourth lens is convex and the image side is convex; the fifth lens is a glass spherical lens with positive focal power, and the object side of the fifth lens is convex and the image side is convex; the sixth lens is a plastic aspheric lens with negative focal power, and the object side of the sixth lens is concave and the image side is concave; the seventh lens is a plastic aspheric lens with positive focal power, and the object side of the seventh lens is convex and the image side is convex; the filter is arranged on the image side of the seventh lens; a stop is arranged between the fourth lens and the fifth lens;

[0011] The effective total focal length of the large-aperture ultra-wide-angle high-definition lens is f, the effective focal length of the first lens is f1, the effective focal length of the second lens is f2, the effective focal length of the third lens is f3, the effective focal length of the fourth lens is f4, the effective focal length of the fifth lens is f5, the effective focal length of the sixth lens is f6, and the effective focal length of the seventh lens is f7, and the following relationships are satisfied: 0.51<f1 / f2<1.32; 2.53<f3 / f4<4.25; 1.58<(f5+f6+f7) / f<5.84; -1.86 <f6 / f7<-0.49。

[0012] As a preferred solution of the present invention, the large-aperture ultra-wide-angle high-definition lens satisfies the following condition: L / h<3.83, wherein: L represents the total length of the large-aperture ultra-wide-angle high-definition lens, and h represents the size of the image plane.

[0013] As a preferred solution of the present invention, the Abbe coefficient of the second lens is greater than 40 and less than 55.

[0014] As a preferred solution of the present invention, the refractive index of the third lens is less than 1.75.

[0015] As a preferred solution of the present invention, the refractive index of the fourth lens is less than 1.65.

[0016] As a preferred solution of the present invention, the first lens is a meniscus lens.

[0017] In addition, the present invention also provides a camera device, which includes the above-mentioned large-aperture ultra-wide-angle high-definition lens.

[0018] Compared with the prior art, the optical lens obtained by the present invention by using 2 glass spherical lenses and 5 plastic aspherical lenses has a compact structure, small size, and greatly reduces the weight of the lens, reduces costs and speeds up the research and development cycle. The optical parameters in the optical lens system provided by the present invention are better matched with the imaging conditions, so that the aberration of the lens system is corrected to a large extent, and the MTF resolution is high, ensuring high definition and uniform imaging on the entire image surface, and can match 1 / 2.5 chips (more than 8 million pixels). The field of view of the lens of the present invention reaches more than 160°, FNO. reaches 1.2, the luminous flux is large, and the night photography effect is better; in addition, all optical glass lenses adopt a spherical design, the lens cold processing process performance is good, the glass material cost is low and the price of the finished lens is also low, and the mass production yield is high; all plastic lenses have good processing performance, shortening the research and development cycle and improving research and development efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of a lens according to an embodiment of the present invention.

[0020] Figure 2 This is a 160lp / mm MTF analysis diagram of an embodiment of the present invention.

[0021] Figure 3 4 is a defocus curve diagram of an embodiment of the present invention.

[0022] Figure 4 4 is a field curvature diagram according to an embodiment of the present invention.

[0023] Figure 5 : is an F-Theta distortion diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

[0025] Example 1

[0026] like Figure 1As shown, this embodiment provides a large-aperture ultra-wide-angle high-definition lens, which includes, along the optical axis from the object plane to the image plane, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7 and a filter E8, wherein the first lens E1 is a glass spherical lens with negative focal power, and the object side of the first lens E1 is convex and the image side is concave, the second lens E2 is a plastic aspherical lens with negative focal power, and the object side of the second lens E2 is concave and the image side is concave; the third lens E3 is a plastic aspherical lens with positive focal power, and the object side of the third lens E3 is convex and the image side is concave. The fourth lens E4 is a plastic aspherical lens with positive focal power, and the object side of the fourth lens E4 is convex, and the image side is convex; the fifth lens E5 is a glass spherical lens with positive focal power, and the object side of the fifth lens E5 is convex, and the image side is convex; the sixth lens E6 is a plastic aspherical lens with negative focal power, and the object side of the sixth lens E6 is concave, and the image side is concave; the seventh lens E7 is a plastic aspherical lens with positive focal power, and the object side of the seventh lens E7 is convex, and the image side is convex; the filter E8 is arranged on the image side of the seventh lens E7; an aperture ST is arranged between the fourth lens E4 and the fifth lens E5; from Figure 1 It can be seen that the fourth lens E4 and the fifth lens E5 are both biconvex lenses, which can reduce the tolerance of tilt and decentering and improve the assembly yield.

[0027] Among them: Figure 1 As shown, the object side of the first lens E1 is S1, and the image side is S2, the object side of the second lens E2 is S3, and the image side is S4, the object side of the third lens E3 is S5, and the image side is S6, the object side of the fourth lens E4 is S7, and the image side is S8, the object side of the fifth lens E5 is S9, and the image side is S10, the object side of the sixth lens E6 is S11, and the image side is S12, and the object side of the seventh lens E7 is S13, and the image side is S14.

[0028] The effective total focal length of the large-aperture ultra-wide-angle high-definition lens is f, the effective focal length of the first lens is f1, the effective focal length of the second lens is f2, the effective focal length of the third lens is f3, the effective focal length of the fourth lens is f4, the effective focal length of the fifth lens is f5, the effective focal length of the sixth lens is f6, and the effective focal length of the seventh lens is f7, and the following relationships are satisfied: 0.51<f1 / f2<1.32; 2.53<f3 / f4<4.25; 1.58<(f5+f6+f7) / f<5.84; -1.86 <f6 / f7<-0.49;

[0029] When the value of f1 / f2 exceeds the upper limit of 1.32 or is less than 0.51, the eccentricity and tilt between the first lens and the second lens become very sensitive, which has a great impact on the MTF, resulting in a significant reduction in yield and instability. Strict size control also increases costs. Therefore, the optical lens in the embodiment of the present invention can achieve better imaging quality and improve the stability of the yield when the condition 0.51<f1 / f2<1.32 is met.

[0030] In this embodiment, the large-aperture ultra-wide-angle high-definition lens satisfies the following condition: L / h<3.83, wherein: L represents the total length of the large-aperture ultra-wide-angle high-definition lens, and h represents the size of the image plane.

[0031] In this embodiment, the Abbe coefficient of the second lens E2 is greater than 40 and less than 55.

[0032] In this embodiment, the refractive index of the third lens E3 is less than 1.75.

[0033] In this embodiment, the refractive index of the fourth lens element E4 is less than 1.65.

[0034] In this embodiment, the first lens E1 is a meniscus lens.

[0035] In order to verify the optical performance of the large-aperture ultra-wide-angle high-definition lens of this embodiment, in one embodiment, the effective focal length of the optical system is 2.90 mm, the clear aperture is F / 1.2, the total length of the optical system is 22.35 mm, the field of view angle is 160°, the thickness of the filter is 0.7 mm, the refractive index is 1.52, and the Abbe constant is 64.2; the parameters of each lens are listed in Table 1 and Table 2 respectively.

[0036] Table 1

[0037]

[0038]

[0039] Table 2

[0040]

[0041]

[0042]

[0043]

[0044] In Table 1: Surf is the surface number, Radius is the radius of curvature, Thickness is the thickness of the spherical lens, Index is the refractive index, ABB is the dispersion coefficient, and EFL-E is the focal length.

[0045] In Table 1, mirror numbers 1 and 2 successively represent the two mirrors of lens 1 along the light incident direction, mirror numbers 3 and 4 represent the two mirrors of lens 2 along the light incident direction, mirror numbers 5 and 6 represent the two mirrors of lens 3 along the light incident direction, mirror numbers 7 and 8 represent the two mirrors of lens 4 along the light incident direction, mirror number 9 represents the aperture plane of the lens, mirror numbers 10 and 11 represent the two mirrors of lens five along the light incident direction, mirror numbers 12 and 13 represent the two mirrors of lens six along the light incident direction, mirror numbers 14 and 15 represent the two mirrors of lens seven along the light incident direction, mirror numbers 16 and 17 represent the two mirrors of the filter along the light incident direction, and mirror number 18 represents the image plane.

[0046] It can be obtained from Table 1 that the effective focal lengths of the above lenses satisfy the following relational expressions: 0.51 < f1 / f2 < 1.32; 2.53 < f3 / f4 < 4.25; 1.58 < (f5 + f6 + f7) / f < 5.84; -1.86 < f6 / f7 < -0.49 for the design.

[0047] The Abbe number of the second lens is 45.1, satisfying being greater than 40 and less than 55.

[0048] In the embodiment of the present invention, L / H = 3.19, satisfying L / h < 3.83, where: L represents the total length of the optical lens, and h represents the size of the image plane.

[0049] In the embodiment of the present invention, the refractive index of the third lens is 1.54, satisfying that the refractive index of the third lens is less than 1.75

[0050] In the embodiment of the present invention, the refractive index of the fourth lens is 1.66, satisfying that the refractive index of the fourth lens is less than 1.65.

[0051] Table 2 shows the aspheric data of all plastic aspheric lenses, namely the second lens E2, the third lens E3, the fourth lens E4, the sixth lens E6, and the seventh lens E7.

[0052] In the embodiment of the present invention, Figure 2 It is a modulation transfer function (MTF) curve graph in the visible light band, representing the comprehensive resolution ability of the optical system. In the graph, the horizontal axis represents the spatial frequency, unit: cycles per millimeter (cycles / mm), and the vertical axis represents the value of the modulation transfer function (MTF). The value of MTF is used to evaluate the imaging quality of the lens, and the value range is 0 - 1. In particular, the optical transfer function is a more accurate, intuitive, and common way to evaluate the imaging quality of an optical system. The higher and smoother its curve, the better the imaging quality of the system and the stronger the ability to restore the real image; from Figure 2It can be seen that when the spatial frequency of the visible light band is 160lp / mm, the MTF of the imaging area near the center is greater than 0.65, and the imaging quality is good. Figure 3 It can be seen from the defocus curve that the focal depth of the lens is good. The optical lens provided by this specific implementation corrects various aberrations, such as spherical aberration, coma, astigmatism, field curvature, magnification chromatic aberration, position chromatic aberration, etc., thereby improving the resolution and achieving a resolution of 8 million pixels under white light. Figure 2 and Figure 3 It can be seen that the optical lens of the embodiment of the present invention has corrected and balanced various aberrations to a good level.

[0053] Figure 4 : is a field curvature diagram of an embodiment of the present invention. It can be seen from the figure that the field curvature of the lens is controlled between -0.05 and 0.05.

[0054] Figure 5 : is an F-Theta distortion diagram of an embodiment of the present invention. It can be seen from the diagram that the F-Theta distortion of the lens is controlled below -20%.

[0055] Example 2

[0056] This embodiment provides a camera device, which includes the above-mentioned large-aperture ultra-wide-angle high-definition lens.

[0057] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A large aperture ultra-wide angle high definition lens, comprising, along the optical axis from the object plane to the image plane, the following components: The lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and a filter, wherein the lens has seven lenses in total, wherein the first lens is a glass spherical lens with negative focal power, and the object side of the first lens is convex and the image side is concave; the second lens is a plastic aspherical lens with negative focal power, and the object side of the second lens is concave and the image side is concave; the third lens is a plastic aspherical lens with positive focal power, and the object side of the third lens is convex and the image side is concave; the fourth lens is a plastic aspherical lens with positive focal power, and the object side of the third lens is convex and the image side is concave; A plastic aspheric lens with positive focal power, and the object side of the fourth lens is convex and the image side is convex; the fifth lens is a glass spherical lens with positive focal power, and the object side of the fifth lens is convex and the image side is convex; the sixth lens is a plastic aspheric lens with negative focal power, and the object side of the sixth lens is concave and the image side is concave; the seventh lens is a plastic aspheric lens with positive focal power, and the object side of the seventh lens is convex and the image side is convex; a filter is arranged on the image side of the seventh lens; a stop is arranged between the fourth lens and the fifth lens; The effective total focal length of the large-aperture ultra-wide-angle high-definition lens is f, the effective focal length of the first lens is f1, the effective focal length of the second lens is f2, the effective focal length of the third lens is f3, the effective focal length of the fourth lens is f4, the effective focal length of the fifth lens is f5, the effective focal length of the sixth lens is f6, and the effective focal length of the seventh lens is f7, and the following relationships are satisfied: 0.51<f1 / f2<1.32; 2.53<f3 / f4<4.25; 1.58<(f5+f6+f7) / f<5.84; -1.86 <f6 / f7<-0.49。 2. The large-aperture ultra-wide-angle high-definition lens according to claim 1, characterized in that: The large-aperture ultra-wide-angle high-definition lens satisfies the following condition: L / h<3.83, wherein: L represents the total length of the large-aperture ultra-wide-angle high-definition lens, and h represents the size of the image plane.

3. The large-aperture ultra-wide-angle high-definition lens according to claim 1, characterized in that: The Abbe coefficient of the second lens is greater than 40 and less than 55.

4. The large-aperture ultra-wide-angle high-definition lens according to claim 1, characterized in that: The refractive index of the third lens is less than 1.

75.

5. The large aperture ultra-wide angle high definition lens according to claim 1, characterized in that: The refractive index of the fourth lens is less than 1.

65.

6. A camera device, characterized in that: It comprises a large-aperture ultra-wide-angle high-definition lens as described in any one of claims 1-5.

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