A three-megapixel optical lens and imaging method thereof

Abstract

The invention relates to a 3-megapixel optical lens and an imaging method thereof: the optical lens comprises a front group, an aperture, a rear group and an imaging surface which are sequentially arranged along a light incident path, the front group comprises a first double-concave negative lens and a second plano-convex positive lens which are sequentially arranged, the rear group comprises a third double-concave negative lens, a fourth double-convex positive lens, a fifth double-convex positive lens, a sixth double-convex positive lens and a seventh plano-concave negative lens which are sequentially arranged, the third double-concave negative lens and the fourth double-convex positive lens are glued together to form a glued lens, the optical lens has good imaging effect, can perform high-definition imaging at a longer distance, solves the problem that the existing front-view lens can only monitor a distance within 100 meters and cannot clearly present monitoring images at a longer distance, has a simple structure, low cost, a long imaging distance and high overall reliability.

Description

Technical Field

[0001] The invention relates to a 3-million-pixel optical lens and an imaging method thereof. Background Art

[0002] At present, science and technology are changing with each passing day, and optical lenses are also constantly developing towards the characteristics of full spectrum, large image surface, and high resolution. The existing lenses are difficult to meet market demand in terms of pixels, performance, and cost. In particular, the monitoring distance of the vehicle-mounted front-view lenses on the market is within 100 meters, and the monitoring images at a longer distance cannot be clearly presented. Summary of the invention

[0003] The present invention aims to improve the problems existing in the above-mentioned prior art, that is, the technical problem to be solved by the present invention is to provide a 3-megapixel optical lens and an imaging method thereof, which adopts a full glass spherical lens to achieve the purpose of providing high-definition image quality within a range of 3 meters to 300 meters.

[0004] The solution adopted by the present invention to solve the technical problem is a 3-megapixel optical lens: including a front group, an aperture, a rear group, and an imaging surface arranged in sequence along the incident light path of the light, the front group includes a first biconcave negative lens and a second plano-convex positive lens arranged in sequence, and the rear group includes a third biconcave negative lens, a fourth biconvex positive lens, a fifth biconvex positive lens, a sixth biconvex positive lens, and a seventh plano-concave negative lens arranged in sequence.

[0005] Furthermore, the third double concave negative lens and the fourth double convex positive lens are glued together to form a glued lens.

[0006] Furthermore, the air gap between the first biconcave negative lens and the second plano-convex positive lens is 2.76-3.4 mm, the air gap between the second plano-convex positive lens and the aperture is 0.4-0.6 mm, the air gap between the aperture and the cemented lens is 1.42-1.81 mm, the air gap between the cemented lens and the fifth biconvex positive lens is 0.1-0.3 mm, the air gap between the fifth biconvex positive lens and the sixth biconvex positive lens is 0-0.2 mm, and the air gap between the sixth biconvex positive lens and the seventh plano-concave negative lens is 0.50-0.60 mm.

[0007] Further, the focal length of the optical system is f, and the focal lengths of the first biconcave negative lens, the second plano-convex positive lens, the third biconcave negative lens, the fourth biconvex positive lens, the fifth biconvex positive lens, the sixth biconvex positive lens, and the seventh plano-concave negative lens are f1, f2, f3, f4, f5, f6, and f7, respectively, wherein f1, f2, f3, f4, f5, f6, and f7 satisfy the following ratio with f: -1.42 <f1 / f<-1.13,1.44<f2 / f<1.67,-0.73<f3 / f<-0.57,0.71<f4 / f<1.11,1.01<f5 / f<1.58,3.11<f6 / f<3.29,-2.23<f7 / f<-1.92。

[0008] Furthermore, the first biconcave negative lens satisfies the relationship: N d ≤1.6, V d ≥55; the second plano-convex positive lens satisfies the relationship: N d ≥1.7, V d ≤40; the third biconcave negative lens satisfies the relationship: N d ≥1.7, V d ≤40; the fourth biconvex positive lens satisfies the relationship: N d ≥1.5, V d ≥50; the fifth biconvex positive lens satisfies the relationship: N d ≥1.7, V d ≤70; the sixth biconvex positive lens satisfies the relationship: N d ≥1.5, V d ≤90; the seventh plano-concave negative lens satisfies the relationship: N d ≥1.6, V d ≤55; where N d is the refractive index, V d is the Abbe constant.

[0009] Furthermore, the total optical length TTL of the optical system and the focal length F of the optical system satisfy: TTL / F≤4.

[0010] An imaging method of a three-megapixel optical lens: light rays pass through a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens from left to right in sequence to form an image on an imaging surface.

[0011] Compared with the prior art, the present invention has the following beneficial effects: good imaging effect, high-definition imaging at a longer distance, solving the problem that the existing front-view lens monitoring distance can only be within 100 meters and the monitoring images at a longer distance cannot be clearly presented, simple structure, low cost, long imaging distance and high overall reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention is further described below in conjunction with the accompanying drawings.

[0013] Figure 1 is a schematic diagram of the optical structure of an embodiment of the present invention;

[0014] Figure 2 is a visible light MTF curve diagram of an embodiment of the present invention;

[0015] Figure 3 is an axial chromatic aberration curve diagram of an embodiment of the present invention;

[0016] Figure 4 4 is a field curvature / distortion curve diagram of an embodiment of the present invention.

[0017] In the figure: 1-first biconcave negative lens; 2-second plano-convex positive lens; 3-third biconcave negative lens; 4-fourth biconvex positive lens; 5-fifth biconvex positive lens; 6-sixth biconvex positive lens; 7-seventh plano-concave negative lens; 8-filter; 9-protective glass; 10-imaging surface; 11-aperture. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0019] like Figure 1 As shown, a 3-megapixel optical lens comprises a front group, an aperture 11, a rear group, and an imaging surface 10 arranged in sequence along the incident light path of the light, wherein the front group comprises a first biconcave negative lens 1 and a second plano-convex positive lens 2 arranged in sequence, and the rear group comprises a third biconcave negative lens 3, a fourth biconvex positive lens 4, a fifth biconvex positive lens 5, a sixth biconvex positive lens 6, and a seventh plano-concave negative lens 7 arranged in sequence;

[0020] The object side surface and the image side surface of the first double concave negative lens are both concave surfaces, the object side surface of the second plano-convex positive lens is convex, and the image side surface is a plane, the object side surface and the image side surface of the third double concave negative lens are both concave surfaces, the object side surface and the image side surface of the fourth double convex positive lens are both convex surfaces, the object side surface and the image side surface of the fifth double convex positive lens are both convex surfaces, the object side surface and the image side surface of the sixth double convex positive lens are both convex surfaces, and the object side surface of the seventh plano-concave negative lens is concave, and the image side surface is a plane;

[0021] The first biconcave negative lens, the second plano-convex positive lens, the third biconcave negative lens, the fourth biconvex positive lens, the fifth biconvex positive lens, the sixth biconvex positive lens and the seventh plano-concave negative lens are all spherical lenses, and are all made of glass.

[0022] In this embodiment, the third biconcave negative lens and the fourth biconvex positive lens are glued together to form a glued lens.

[0023] In this embodiment, a filter 8 and a protective glass 9 are provided on the rear side of the seventh plano-concave negative lens.

[0024] In this embodiment, the air gap between the first biconcave negative lens and the second plano-convex positive lens is 2.76-3.4 mm, the air gap between the second plano-convex positive lens and the aperture is 0.4-0.6 mm, the air gap between the aperture and the cemented lens is 1.42-1.81 mm, the air gap between the cemented lens and the fifth biconvex positive lens is 0.1-0.3 mm, the air gap between the fifth biconvex positive lens and the sixth biconvex positive lens is 0-0.2 mm, and the air gap between the sixth biconvex positive lens and the seventh plano-concave negative lens is 0.50-0.60 mm.

[0025] In this embodiment, the focal length of the optical system is f, and the focal lengths of the first biconcave negative lens, the second plano-convex positive lens, the third biconcave negative lens, the fourth biconvex positive lens, the fifth biconvex positive lens, the sixth biconvex positive lens, and the seventh plano-concave negative lens are f1, f2, f3, f4, f5, f6, and f7, respectively, wherein f1, f2, f3, f4, f5, f6, and f7 satisfy the following ratio with f: -1.42 <f1 / f<-1.13,1.44<f2 / f<1.67,-0.73<f3 / f<-0.57,0.71<f4 / f<1.11,1.01<f5 / f<1.58,3.11<f6 / f<3.29,-2.23<f7 / f<-1.92。

[0026] In this embodiment, the first biconcave negative lens satisfies the relationship: N d ≤1.6, V d ≥55; the second plano-convex positive lens satisfies the relationship: N d ≥1.7, V d ≤40; the third biconcave negative lens satisfies the relationship: N d ≥1.7, V d ≤40; the fourth biconvex positive lens satisfies the relationship: N d ≥1.5, V d ≥50; the fifth biconvex positive lens satisfies the relationship: N d ≥1.7, V d ≤70; the sixth biconvex positive lens satisfies the relationship: N d ≥1.5, V d ≤90; the seventh plano-concave negative lens satisfies the relationship: N d ≥1.6, V d ≤55; where N d is the refractive index, V d is the Abbe constant.

[0027] In this embodiment, the total optical length TTL of the optical system and the focal length F of the optical system satisfy: TTL / F≤4.

[0028] The following table is a table of lens parameters of this embodiment:

[0029] Table 1 Specific lens parameters

[0030]

[0031] In this embodiment, the technical indicators achieved by this optical system are as follows:

[0032] (1) Focal length: EFFL = 6.07mm; (2) Aperture F = 2.03; (3) Field of view: 2w ≥ 70°; (4) Optical distortion: < 20%; (5) Imaging circle diameter greater than φ7; (6) Working band: 420-680nm; (7) Total optical length TTL ≤ 24mm, optical back focus BFL ≥ 6mm; (8) This lens is suitable for 3 million pixel CCD or CMOS cameras.

[0033] Depend on Figure 2 It can be seen that the optical system has good MTF performance in the near-infrared band. The MTF value of the edge field of view is greater than 0.5 at the spatial frequency of 83pl / mm, and the MTF value of the center field of view is greater than 0.7 at the spatial frequency of 83pl / mm, which can meet the three million resolution requirements. Figure 3 and Figure 4 is the axial chromatic aberration curve and field curvature / distortion curve of the optical system. Figure 3 It can be seen that the optical system introduces the higher-order component of spherical aberration, which reduces the residual spherical aberration and thus reduces the dispersion. Figure 4 It can be seen that the field curvature is well corrected. In summary, it can be seen that the optical system has excellent imaging quality and fully meets the requirements of 3 million pixel photography.

[0034] An imaging method of a 3-megapixel optical lens: light rays are imaged on an imaging surface after passing through a first biconcave negative lens, a second plano-convex positive lens, a third biconcave negative lens, a fourth biconvex positive lens, a fifth biconvex positive lens, a sixth biconvex positive lens, a seventh plano-concave negative lens, a filter and a protective glass from left to right.

[0035] Unless otherwise stated, any technical solution disclosed in the present invention disclosed above, if it discloses a numerical range, then the disclosed numerical range is a preferred numerical range, and any technician in the field should understand that the preferred numerical range is only a numerical value with a more obvious technical effect or representative value among many implementable numerical values. Since there are too many numerical values ​​to be exhaustive, the present invention discloses some numerical values ​​to illustrate the technical solution of the present invention, and the numerical values ​​listed above should not constitute a limitation on the scope of protection of the present invention.

[0036] If the words "first", "second" and so on are used in this article to limit components, those skilled in the art should know that the use of "first" and "second" is only for the convenience of description to distinguish the components. Unless otherwise stated, the above words have no special meaning.

[0037] If the present invention discloses or involves components or structures that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, connection using bolts or screws), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by one-piece molding using a casting process) (except when it is obviously impossible to use an one-piece molding process).

[0038] In addition, the orientations or positional relationships indicated by terms such as "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", and "outside" used in any of the technical solutions disclosed in the above-mentioned invention are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this patent, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this patent. Unless otherwise stated, the terms used to indicate shapes used in any of the technical solutions disclosed in the above-mentioned invention include shapes that are approximate, similar, or close to them.

[0039] Any component provided by the present invention may be assembled from a plurality of separate components, or may be a separate component manufactured by an integral forming process.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A 3-megapixel optical lens, characterized in that: The optical lens is composed of a front group, an aperture, a rear group, and an imaging surface arranged in sequence along the incident light path of the light; the front group is composed of a first biconcave negative lens and a second plano-convex positive lens arranged in sequence; the rear group is composed of a third biconcave negative lens, a fourth biconvex positive lens, a fifth biconvex positive lens, a sixth biconvex positive lens, and a seventh plano-concave negative lens arranged in sequence; the object side surface of the second plano-convex positive lens is a convex surface, and the image side surface is a plane; the object side surface of the seventh plano-concave negative lens is a concave surface, and the image side surface is a plane; The air gap between the first biconcave negative lens and the second plano-convex positive lens is 2.76-3.4 mm, the air gap between the second plano-convex positive lens and the aperture is 0.4-0.6 mm, the air gap between the aperture and the cemented lens is 1.42-1.81 mm, the air gap between the cemented lens and the fifth biconvex positive lens is 0.1-0.3 mm, the air gap between the fifth biconvex positive lens and the sixth biconvex positive lens is 0-0.2 mm, and the air gap between the sixth biconvex positive lens and the seventh plano-concave negative lens is 0.50-0.60 mm; The third biconcave negative lens and the fourth biconvex positive lens are glued together to form a glued lens.

2. The three-megapixel optical lens according to claim 1, characterized in that: The focal length of the optical system is f, and the focal lengths of the first biconcave negative lens, the second plano-convex positive lens, the third biconcave negative lens, the fourth biconvex positive lens, the fifth biconvex positive lens, the sixth biconvex positive lens, and the seventh plano-concave negative lens are f1, f2, f3, f4, f5, f6, and f7, respectively, wherein f1, f2, f3, f4, f5, f6, and f7 satisfy the following ratio with f: -1.42 <f1 / f<-1.13,1.44<f2 / f<1.67,-0.73<f3 / f<-0.57,0.71<f4 / f<1.11,1.01<f5 / f<1.58,3.11<f6 / f<3.29,-2.23<f7 / f<-1.92。 3. The three-megapixel optical lens according to claim 2, characterized in that: The first biconcave negative lens satisfies the relationship: N d ≤1.6, V d ≥55; the second plano-convex positive lens satisfies the relationship: N d ≥1.7, V d ≤40; the third biconcave negative lens satisfies the relationship: N d ≥1.7, V d ≤40; the fourth biconvex positive lens satisfies the relationship: N d ≥1.5, V d ≥50; the fifth biconvex positive lens satisfies the relationship: N d ≥1.7, V d ≤70; the sixth biconvex positive lens satisfies the relationship: N d ≥1.5, V d ≤90; the seventh plano-concave negative lens satisfies the relationship: N d ≥1.6, V d ≤55; where N d is the refractive index, V d is the Abbe constant.

4. The three-megapixel optical lens according to claim 3, characterized in that: The total optical length TTL of the optical system and the focal length F of the optical system satisfy the following condition: TTL / F≤4.

5. An imaging method of a 3 million pixel optical lens, using the 3 million pixel optical lens as claimed in claim 4, characterized in that: The light passes through the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens from left to right to form an image on the imaging surface.

Images