CN216718794U - Fixed focus lens - Google Patents

Abstract

The embodiment of the utility model provides a fixed-focus lens, which relates to the technical field of optical lenses, and comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object space to an image space along an optical axis; the first lens, the third lens and the fifth lens have negative focal power, the fourth lens and the sixth lens have positive focal power, and the second lens has positive focal power or negative focal power. The embodiment of the utility model provides a fixed focus lens, which is used for realizing large aperture, small volume, low cost and stable high and low temperature performance of the fixed focus lens.

Description

a fixed focus lens

technical field

The utility model relates to an optical lens technology, in particular to a fixed focus lens.

Background technique

With the rapid development of technology, people have a higher level of understanding of security, and surveillance cameras were born. With the increasing development of security monitoring systems, the requirements for security lenses are getting higher and higher, which are mainly reflected in higher image quality, larger field of view, larger clear aperture and larger target surface.

Utility model content

The embodiment of the present invention provides a fixed-focus lens, so as to realize the large aperture, small volume, low cost and stable high and low temperature performance of the fixed-focus lens.

The embodiment of the present utility model provides a fixed-focus lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens that are sequentially arranged along the optical axis from the object side to the image side;

The first lens, the third lens and the fifth lens have negative refractive power, the fourth lens and the sixth lens have positive refractive power, and the second lens has positive refractive power or negative refractive power optical power.

Optionally, a diaphragm is further included, and the diaphragm is located between the second lens and the third lens, or the diaphragm is located between the third lens and the fourth lens.

Optionally, the object side of the first lens is concave, and the image side of the first lens is concave or convex;

The object side of the second lens is concave, and the image side of the second lens is convex;

The object side of the third lens is convex, and the image side of the third lens is concave;

The object side of the fourth lens is convex, and the image side of the fourth lens is convex;

The object side of the fifth lens is convex, and the image side of the fifth lens is concave;

The object side of the sixth lens is convex, and the image side of the sixth lens is convex.

Optionally, the first lens and the fourth lens are glass spherical lenses;

The second lens, the third lens, the fifth lens and the sixth lens are plastic aspherical lenses.

Optionally, the fourth lens is a glass spherical lens;

The first lens, the second lens, the third lens, the fifth lens and the sixth lens are plastic aspherical lenses.

Optionally, satisfy:

-0.459＜φ1/φ＜-0.090;

-0.123＜φ2/φ＜0.245;

-0.295＜φ3/φ＜-0.009;

0.643＜φ4/φ＜1.089;

-1.199＜φ5/φ＜-0.896;

1.002＜φ6/φ＜1.291;

Wherein, φ1 is the refractive power of the first lens, φ2 is the refractive power of the second lens, φ3 is the refractive power of the third lens, φ4 is the refractive power of the fourth lens, φ5 is the refractive power of the fifth lens, φ6 is the refractive power of the sixth lens, and φ is the refractive power of the fixed-focus lens.

Optionally, satisfy:

1.52≤n1≤1.69;

1.40≤n2≤1.71;

1.48≤n3≤1.76;

1.40≤n4≤1.65;

1.59≤n5≤1.70;

1.46≤n6≤1.59;

Wherein, n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, and n5 is the refractive index of the The refractive index of the fifth lens, n6 is the refractive index of the sixth lens.

Optionally, satisfy:

33.6≤v1≤95;

23.8≤v2≤95;

26.2≤v3≤39.7;

37.8≤v4≤61;

16.4≤v5≤35;

39.2≤v6≤95;

Wherein, v1 is the dispersion coefficient of the first lens, v2 is the dispersion coefficient of the second lens, v3 is the dispersion coefficient of the third lens, v4 is the dispersion coefficient of the fourth lens, and v5 is the The dispersion coefficient of the fifth lens, v6 is the dispersion coefficient of the sixth lens.

Optionally, satisfy:

IC/TTL≥0.310;

Wherein, IC is the image plane diameter of the fixed-focus lens, and TTL is the total length of the fixed-focus lens.

Optionally, satisfy:

BFL/TTL≥0.30;

Wherein, BFL is the back focus of the fixed-focus lens, and TTL is the total length of the fixed-focus lens.

The embodiment of the present invention provides a fixed-focus lens, wherein the first lens has negative refractive power, the second lens has positive refractive power or negative refractive power, the third lens has negative refractive power, and the fourth lens has positive refractive power , the fifth lens has a negative refractive power, and the sixth lens has a positive refractive power, thereby realizing the large aperture, small volume, low cost, and stable high and low temperature performance of the fixed-focus lens.

Description of drawings

1 is a specific structural diagram of a fixed focus lens in the first embodiment;

2 is a spherical aberration curve diagram of a fixed-focus lens in the first embodiment;

3 is a chromatic aberration curve diagram of a fixed-focus lens in the first embodiment;

4 is a specific structural diagram of a fixed focus lens in the second embodiment;

5 is a spherical aberration curve diagram of a fixed-focus lens in the second embodiment;

6 is a chromatic aberration curve diagram of a fixed-focus lens in the second embodiment;

7 is a specific structural diagram of a fixed-focus lens in the third embodiment;

8 is a spherical aberration curve diagram of a fixed-focus lens in the third embodiment;

FIG. 9 is a chromatic aberration curve diagram of a fixed-focus lens in the third embodiment.

Detailed ways

The present utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, the drawings only show some but not all structures related to the present invention.

Example 1

FIG. 1 is a specific structural diagram of a fixed-focus lens in Embodiment 1. Referring to FIG. 1, the fixed-focus lens includes a first lens 1, a second lens 2, a third lens 1, a second lens 2, a third lens and a Lens 3 , fourth lens 4 , fifth lens 5 and sixth lens 6 . The first lens 1 , the third lens 3 and the fifth lens 5 have negative refractive power, the fourth lens 4 and the sixth lens 6 have positive refractive power, and the second lens 2 has positive refractive power.

The embodiment of the present invention provides a fixed-focus lens. The first lens 1 has negative refractive power, the second lens 2 has positive refractive power or negative refractive power, the third lens 3 has negative refractive power, and the fourth lens 4 has negative refractive power. It has positive refractive power, the fifth lens 5 has negative refractive power, and the sixth lens 6 has positive refractive power, thereby realizing the large aperture, small volume, low cost, and stable high and low temperature performance of the fixed-focus lens.

Optionally, the fixed-focus lens further includes a diaphragm STOP, and the diaphragm STOP is located between the second lens 2 and the third lens 3 .

Optionally, the object side surface of the first lens 1 is concave, and the image side surface of the first lens 1 is concave, that is, the first lens 1 is a biconcave lens. The object side surface of the second lens 2 is a concave surface, and the image side surface of the second lens 2 is a convex surface, that is, the second lens 2 is a meniscus lens. The object side of the third lens 3 is convex, and the image side of the third lens 3 is concave, that is, the third lens 3 is a convex-concave lens. The object side surface of the fourth lens 4 is a convex surface, and the image side surface of the fourth lens 4 is a convex surface, that is, the fourth lens 4 is a biconvex lens. The object side surface of the fifth lens 5 is a convex surface, and the image side surface of the fifth lens 5 is a concave surface, that is, the fifth lens 5 is a convex-concave lens. The object side of the sixth lens 6 is a convex surface, and the image side of the sixth lens 6 is a convex surface, that is, the sixth lens 6 is a biconvex lens.

Optionally, the first lens 1 and the fourth lens 4 are glass spherical lenses. The second lens 2 , the third lens 3 , the fifth lens 5 and the sixth lens 6 are plastic aspherical lenses. The embodiment of the present utility model provides a telephoto lens with F.NO<1.56, which adopts glass-plastic mixed lens collocation, realizes the characteristics of low cost and stable high and low temperature performance, can meet the use conditions of -40°C-80°C, and the maximum It can match the 1/2.7″ target surface sensor chip, and has the characteristics of small size, small purple fringing, small distortion, and day and night confocal.

Optionally, the refractive powers of the first lens 1 to the sixth lens 6 satisfy: -0.459<φ1/φ<-0.090, -0.123<φ2/φ<0.245, -0.295<φ3/φ<-0.009, 0.643 <φ4/φ<1.089, -1.199<φ5/φ<-0.896, 1.002<φ6/φ<1.291. Among them, φ1 is the refractive power of the first lens 1, φ2 is the refractive power of the second lens 2, φ3 is the refractive power of the third lens 3, φ4 is the refractive power of the fourth lens 4, and φ5 is the fifth lens. The refractive power of the lens 5, φ6 is the refractive power of the sixth lens 6, and φ is the refractive power of the fixed-focus lens.

Optionally, the refractive indices of the first lens 1 to the sixth lens 6 satisfy: 1.52≤n1≤1.69, 1.40≤n2≤1.71, 1.48≤n3≤1.76, 1.40≤n4≤1.65, 1.59≤n5≤1.70, 1.46 ≤n6≤1.59. Among them, n1 is the refractive index of the first lens 1, n2 is the refractive index of the second lens 2, n3 is the refractive index of the third lens 3, n4 is the refractive index of the fourth lens 4, and n5 is the refractive index of the fifth lens 5 ratio, n6 is the refractive index of the sixth lens 6 .

Optionally, the dispersion coefficients of the first lens 1 to the sixth lens 6 satisfy: 33.6≤v1≤95, 23.8≤v2≤95, 26.2≤v3≤39.7, 37.8≤v4≤61, 16.4≤v5≤35, 39.2 ≤v6≤95. where v1 is the dispersion coefficient of the first lens 1, v2 is the dispersion coefficient of the second lens 2, v3 is the dispersion coefficient of the third lens 3, v4 is the dispersion coefficient of the fourth lens 4, and v5 is the dispersion coefficient of the fifth lens 5 coefficient, v6 is the dispersion coefficient of the sixth lens 6 .

Optionally, the fixed-focus lens satisfies: IC/TTL≥0.310. Among them, IC is the image surface diameter of the fixed-focus lens, and TTL is the total length of the fixed-focus lens. When IC/TTL≥0.310 is satisfied, the fixed-focus lens has a larger target surface and a smaller volume, that is, it can ensure that the fixed-focus lens has better imaging quality, clearer picture and smaller volume.

Optionally, the fixed-focus lens satisfies: BFL/TTL≥0.30. Among them, BFL is the back focus of the fixed-focus lens, and TTL is the total length of the fixed-focus lens. When the BFL/TTL≥0.30 is satisfied, the back focus of the fixed-focus lens will not be too small, so as to ensure sufficient installation space for the imaging sensor and the flat filter.

A design value of the fixed focus lens in the first embodiment of Table 1

face number face shape Radius of curvature (mm) Thickness(mm) refractive index Dispersion coefficient half diameter S1 spherical -20.76 1.83 1.57 34.6 3.348 S2 spherical 45.89 1.29 2.852 S3 Aspherical -3.4 2.49 1.64 39.6 2.600 S4 Aspherical -3.96 0.1 3.334 diaphragm flat unlimited 0.1 3.197 S6 Aspherical 11.7 0.72 1.54 35.4 3.366 S7 Aspherical 8.64 0.1 3.390 S8 spherical 7.94 3.04 1.44 38.8 4.200 S9 spherical -8.33 0.1 4.200 S10 Aspherical 7.88 1.73 1.64 22.8 3.362 S11 Aspherical 2.69 0.31 3.045 S12 Aspherical 4.89 3.46 1.54 91.1 2.900 S13 Aspherical -9.97 5.3 2.999 S14 flat unlimited 0.7 1.52 64.21 3.600 S15 flat unlimited 0.82 3.600

Table 1 shows a design value of the fixed-focus lens in the first embodiment, and its specific value can be adjusted according to product requirements, which is not a limitation to the embodiment of the present invention. The prime lenses shown in Table 1 may be as shown in FIG. 1 . A lens generally includes two surfaces, each of which is a refractive surface. The surface numbers in Table 1 are numbered according to the surface of each lens. The surface number "S1" represents the front surface of the first lens 1, the surface number "S2" represents the rear surface of the first lens 1, and so on, and will not be repeated here. It should be noted that the curvature radius represents the degree of curvature of the lens surface, a positive curvature radius value indicates that the curvature center is on the side of the surface close to the image side, and a negative curvature radius value indicates that the curvature center is on the surface away from the image side. The value in the "Thickness" column represents the axial distance from the current surface to the next surface. The column "Refractive Index" indicates the refractive index of the medium between the current surface and the next surface. The blanks in the "refractive index" column are the refractive index of air, and the refractive index of air is 1. The dispersion coefficient represents the dispersion characteristics of the material between the current surface and the next surface to light, and the space represents the current position is air.

Optionally, the aspheric formula looks like this:

Among them, Z is the sag of the aspheric surface, c is the basic curvature at the vertex, k is the conic constant, r is the radial coordinate perpendicular to the optical axis, a _i is the high-order coefficient, and a _i r ²ⁱ is the aspheric surface higher order terms.

A design value of the aspheric coefficient of the lens in the fixed-focus lens in the first embodiment of Table 2

Table 2 is a design value of the aspheric coefficient of the lens in the fixed-focus lens in the first embodiment, and its specific value can be adjusted according to product requirements, which is not a limitation of the embodiment of the present invention. The prime lenses shown in Table 2 may be as shown in FIG. 1 . The column of "surface number" in Table 2 is consistent with the meaning of "surface number" in Table 1. For example, the surface number "S3" also represents the front surface of the second lens 2 . "E" in each embodiment of the present invention represents an index with the base 10.

Embodiment 2

The same points as in the first embodiment will not be repeated, and the difference from the first embodiment is that the second lens 2 has a negative refractive power. The first lens 1 is a plastic aspheric lens.

A design value of fixed focus lens in the second embodiment of table 3

face number face shape Radius of curvature (mm) Thickness(mm) refractive index Dispersion coefficient half diameter S1 Aspherical -15.5 1.14 1.64 95 3.383 S2 Aspherical 84.12 1.31 3.014 S3 Aspherical -3.37 2.17 1.43 95 2.800 S4 Aspherical -4.12 0.32 3.364 diaphragm flat unlimited 0.45 3.164 S6 Aspherical 12.33 0.7 1.71 27.2 3.389 S7 Aspherical 8.26 0.1 3.449 S8 spherical 7.35 3.5 1.6 48 4.200 S9 spherical -9.37 0.1 4.200 S10 Aspherical 7.65 1.28 1.65 34 3.536 S11 Aspherical 2.6 0.25 3.227 S12 Aspherical 4.12 3.15 1.51 95 3.100 S13 Aspherical -10.04 5.3 3.083 S14 flat unlimited 0.7 1.52 64.21 3.600 S15 flat unlimited 1.54 3.600

Table 3 shows a design value of the fixed-focus lens in the second embodiment, and its specific value can be adjusted according to product requirements, which is not a limitation of the embodiment of the present invention. The prime lenses shown in Table 3 may be as shown in FIG. 4 .

A design value of the aspheric coefficient of the lens in the fixed-focus lens in the second embodiment of table 4

Table 4 is a design value of the aspheric coefficient of the lens in the fixed-focus lens in the second embodiment, and its specific value can be adjusted according to product requirements, which is not a limitation of the embodiment of the present invention. The prime lenses shown in Table 4 may be as shown in FIG. 4 .

Embodiment 3

The same points with the first embodiment will not be repeated, and the difference from the first embodiment is that the diaphragm STOP is located between the third lens 3 and the fourth lens 4 . The object side of the first lens 1 is a concave surface, the image side of the first lens 1 is a convex surface, and the first lens 1 is a meniscus lens.

A design value of the fixed focus lens in the third embodiment of table 5

face number face shape Radius of curvature (mm) Thickness(mm) refractive index Dispersion coefficient half diameter S1 spherical -17.13 2.1 1.62 70 3.350 S2 spherical -60.17 1.23 2.885 S3 Aspherical -3.36 2.51 1.66 24.8 2.600 S4 Aspherical -3.97 0.35 3.361 s5 Aspherical 13 0.7 1.53 38.7 3.364 S6 Aspherical 9.18 0.72 3.371 diaphragm flat unlimited -0.6 3.254 S8 spherical 8.14 3.01 1.44 60 4.200 S9 spherical -8.29 0.1 4.200 S10 Aspherical 7.96 1.69 1.64 17.4 3.361 S11 Aspherical 2.68 0.33 3.043 S12 Aspherical 4.99 3.36 1.54 40.2 2.900 S13 Aspherical -9.86 5.3 3.019 S14 flat unlimited 0.7 1.52 64.21 3.600 S15 flat unlimited 0.72 3.600

Table 5 shows a design value of the fixed-focus lens in the third embodiment, and its specific value can be adjusted according to product requirements, which is not a limitation of the embodiment of the present invention. The prime lenses shown in Table 5 may be as shown in FIG. 7 .

A design value of the aspheric coefficient of the lens in the fixed focus lens in the third embodiment of table 6

Table 6 is a design value of the aspheric coefficient of the lens in the fixed-focus lens in the third embodiment, and its specific numerical value can be adjusted according to product requirements, and is not a limitation of the embodiment of the present invention. The prime lenses shown in Table 6 may be as shown in FIG. 7 .

Note that the above are only preferred embodiments of the present invention and applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the protection of the present invention scope. Therefore, although the present utility model has been described in detail through the above embodiments, the present utility model is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present utility model. Rather, the scope of the present invention is determined by the scope of the appended claims.

Claims (10)

1. A fixed-focus lens, characterized in that it comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side along the optical axis; The first lens, the third lens and the fifth lens have negative refractive power, the fourth lens and the sixth lens have positive refractive power, and the second lens has positive refractive power or negative refractive power optical power. 2 . The fixed-focus lens according to claim 1 , further comprising a diaphragm, the diaphragm is located between the second lens and the third lens, or the diaphragm is located in the between the third lens and the fourth lens. 3. The fixed-focus lens according to claim 1, wherein the object side of the first lens is concave, and the image side of the first lens is concave or convex; The object side of the second lens is concave, and the image side of the second lens is convex; The object side of the third lens is convex, and the image side of the third lens is concave; The object side of the fourth lens is convex, and the image side of the fourth lens is convex; The object side of the fifth lens is convex, and the image side of the fifth lens is concave; The object side of the sixth lens is convex, and the image side of the sixth lens is convex. 4. The fixed-focus lens according to claim 1, wherein the first lens and the fourth lens are glass spherical lenses; The second lens, the third lens, the fifth lens and the sixth lens are plastic aspherical lenses. 5. The fixed-focus lens according to claim 1, wherein the fourth lens is a glass spherical lens; The first lens, the second lens, the third lens, the fifth lens and the sixth lens are plastic aspherical lenses. 6. fixed focus lens according to claim 1, is characterized in that, satisfy: -0.459＜φ1/φ＜-0.090; -0.123＜φ2/φ＜0.245; -0.295＜φ3/φ＜-0.009; 0.643＜φ4/φ＜1.089; -1.199＜φ5/φ＜-0.896; 1.002＜φ6/φ＜1.291; Wherein, φ1 is the refractive power of the first lens, φ2 is the refractive power of the second lens, φ3 is the refractive power of the third lens, φ4 is the refractive power of the fourth lens, φ5 is the refractive power of the fifth lens, φ6 is the refractive power of the sixth lens, and φ is the refractive power of the fixed-focus lens. 7. fixed focus lens according to claim 1, is characterized in that, satisfy: 1.52≤n1≤1.69; 1.40≤n2≤1.71; 1.48≤n3≤1.76; 1.40≤n4≤1.65; 1.59≤n5≤1.70; 1.46≤n6≤1.59; Wherein, n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, and n5 is the refractive index of the The refractive index of the fifth lens, n6 is the refractive index of the sixth lens. 8. fixed focus lens according to claim 1, is characterized in that, satisfy: 33.6≤v1≤95; 23.8≤v2≤95; 26.2≤v3≤39.7; 37.8≤v4≤61; 16.4≤v5≤35; 39.2≤v6≤95; Wherein, v1 is the dispersion coefficient of the first lens, v2 is the dispersion coefficient of the second lens, v3 is the dispersion coefficient of the third lens, v4 is the dispersion coefficient of the fourth lens, and v5 is the The dispersion coefficient of the fifth lens, v6 is the dispersion coefficient of the sixth lens. 9. fixed focus lens according to claim 1, is characterized in that, satisfy: IC/TTL≥0.310; Wherein, IC is the image plane diameter of the fixed-focus lens, and TTL is the total length of the fixed-focus lens. 10. The fixed-focus lens according to claim 1, wherein: BFL/TTL≥0.30; Wherein, BFL is the back focus of the fixed-focus lens, and TTL is the total length of the fixed-focus lens.

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