CN111679404A - High-pixel telescopic lens - Google Patents

Abstract

The invention discloses a high-pixel telephoto lens, which is provided with 6 lenses from an object side to an image side, wherein the first lens has positive refractive power, and the object side surface is a convex surface; the second lens has positive refractive power, the object side surface is a convex surface, and the image side surface is a concave surface; the third lens has negative refractive power, the object side surface is a convex surface, and the image side surface is a concave surface; the fourth lens has negative refractive power, the object side surface is a concave surface, and the image side surface is a concave surface; the fifth lens has negative refractive power; all surfaces of the 6 lenses are aspheric surfaces, and the following conditions are met: TTL/F is less than 0.6, TTL is the optical total length of an optical system of the high-pixel telescopic lens, and F is the focal length of the optical system; 0.25< T34/TTL <0.5, T34 is the air space on the optical axis of the third lens and the fourth lens; 0< | F4/F | 0.3, wherein F4 is the focal length of the fourth lens element. The high-pixel telescopic lens is a telescopic optical imaging lens with long focal length and good imaging quality, and is applicable to portable electronic products.

Description

High-pixel telescopic lens

Technical Field

The invention belongs to the technical field of optical imaging lenses, and relates to a high-pixel telescopic lens.

Background

With the popularization of portable electronic products such as smart phones and the like and the continuous update of hardware of electric coupling devices or complementary metal oxide semiconductor image sensors in lenses, a double-shot concept is proposed in a shooting function, namely, zooming is realized by a method of combining two optical lenses and an image processing algorithm. In the double-shot lens, one telephoto lens has the characteristics of large magnification, small depth of field and the like, and is beneficial to blurring the image background, so that a better shooting effect is obtained. Meanwhile, in order to match with a larger-sized chip to pursue a demand for higher resolution, a telescopic optical imaging lens having a long focal length and good imaging quality, which is applicable to a portable electronic product, is urgently needed.

Disclosure of Invention

In order to solve the above technical problems, an object of the present invention is to provide a high-pixel telescopic optical imaging lens having a long focal length and good imaging quality.

The high-pixel telephoto lens system of the present invention includes a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, and a sixth lens element arranged in this order from an object side to an image side along an optical axis,

the first lens has positive refractive power, and the object side surface of the first lens is a convex surface; the second lens has positive refractive power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the third lens has negative refractive power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the fourth lens has negative refractive power, the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a concave surface; the fifth lens has a negative refractive power; a diaphragm is arranged in front of the first lens, all surfaces of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are aspheric and plastic lenses, and the following conditions are met:

TTL/F<0.6

wherein, TTL is the optical total length of the optical system of the high-pixel telescopic lens; f is the focal length of the optical system;

0.25<T34/TTL<0.5

wherein T34 is an air space on the optical axis between the third lens and the fourth lens;

0<∣F4/F∣<0.3

where F4 is the focal length of the fourth lens.

In the high-pixel telephoto lens of the present invention, an optical system of the high-pixel telephoto lens further satisfies the following conditions:

TTL/IH<4.2

wherein IH is half image height.

In the high-pixel telephoto lens system of the present invention, the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, and the sixth lens element all adopt even-order aspheric plastic lenses, and aspheric coefficients satisfy the following equation:

wherein Z is an aspheric sagittal height, c is an aspheric paraxial curvature, y is a lens aperture, k is a conic coefficient, a4 is a 4-th aspheric coefficient, a6 is a 6-th aspheric coefficient, A8 is an 8-th aspheric coefficient, a10 is a 10-th aspheric coefficient, a12 is a 12-th aspheric coefficient, a14 is a 14-th aspheric coefficient, a16 is a 16-th aspheric coefficient, a18 is an 18-th aspheric coefficient, and a20 is a 20-th aspheric coefficient.

Compared with the existing lens, the high-pixel telephoto lens has longer focal length and better telephoto effect if the total length is the same; if the focal length is the same, the total length of the lens is shorter and the lens is more miniaturized. The high-pixel telescopic lens is a telescopic optical imaging lens with long focal length and good imaging quality, and is applicable to portable electronic products.

Drawings

FIG. 1 is a two-dimensional view of an optical system of a high-pixel telephoto lens system according to embodiment 1 of the present invention;

fig. 2 is an astigmatism graph of the optical system of example 1;

FIG. 3 is a graph of the optical distortion of the optical system of example 1;

FIG. 4 is a contrast plot of the optical system of example 1;

FIG. 5 is a two-dimensional view of an optical system of embodiment 2 of a high-pixel telephoto lens system according to the present invention;

fig. 6 is an astigmatism graph of the optical system of example 2;

FIG. 7 is a graph showing an optical distortion of the optical system of example 2;

fig. 8 is a graph of relative illuminance of the optical system of example 2.

Detailed Description

The high-pixel telephoto lens system of the present invention includes a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, and a sixth lens element arranged in this order from an object side to an image side along an optical axis,

the first lens has positive refractive power, and the object side surface of the first lens is a convex surface; the second lens has positive refractive power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the third lens has negative refractive power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the fourth lens has negative refractive power, the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a concave surface; the fifth lens has a negative refractive power; a diaphragm is arranged in front of the first lens, all surfaces of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are aspheric and plastic lenses, and the following conditions are met:

the first condition is as follows:

TTL/F<0.6

wherein, TTL is the optical total length of the optical system of the high-pixel telescopic lens; f is the focal length of the optical system. The condition is satisfied, the total length of the optical system is favorably controlled to be smaller than the effective focal length of the optical imaging system, the miniaturization of the optical system structure can be ensured, and the characteristics of large imaging magnification and small depth of field of the telescopic lens under the long focal length are satisfied.

And a second condition:

0.25<T34/TTL<0.5

where T34 is an air space on the optical axis between the third lens and the fourth lens. This condition is used to control the air space between the third lens and the fourth lens, thereby increasing the effective focal length of the entire optical system.

And (3) carrying out a third condition:

0<∣F4/F∣<0.3

where F4 is the focal length of the fourth lens. Satisfying this condition is advantageous for ensuring the telephoto characteristic of the lens, making the angle of view of the lens small while the effective focal length large.

In the high-pixel telephoto lens of the present invention, an optical system of the high-pixel telephoto lens further satisfies the following conditions:

TTL/IH<4.2

wherein IH is half image height.

In the high-pixel telephoto lens system of the present invention, the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, and the sixth lens element all adopt even-order aspheric plastic lenses, and aspheric coefficients satisfy the following equation:

wherein Z is an aspheric sagittal height, c is an aspheric paraxial curvature, y is a lens aperture, k is a conic coefficient, a4 is a 4-th aspheric coefficient, a6 is a 6-th aspheric coefficient, A8 is an 8-th aspheric coefficient, a10 is a 10-th aspheric coefficient, a12 is a 12-th aspheric coefficient, a14 is a 14-th aspheric coefficient, a16 is a 16-th aspheric coefficient, a18 is an 18-th aspheric coefficient, and a20 is a 20-th aspheric coefficient.

Example 1

In this embodiment, the fifth lens element has negative refractive power, and has a concave object-side surface and a convex image-side surface; the sixth lens element has negative refractive power, and has a convex object-side surface and a concave image-side surface.

The design parameters of the lens are shown in tables 1 and 2:

table 1:

table 2:

the corresponding parameters in this embodiment are shown in table 3:

table 3:

FOV	18°
		TTL	12.2
F	20.6
		F4	3.0966
TTL/F	0.592
		T34/TTL	0.33
∣F4/F∣	0.15
		TTL/IH	4.107

referring to fig. 1, the lenses of the optical system are relatively symmetrical in shape, so that the optical system is convenient to mold and produce, and the lenses are reasonable in spacing and convenient to design in the later period;

referring to fig. 2, the astigmatism of the optical system shown is controlled to be within ± 0.05.

Referring to fig. 3, the optical distortion curve of the optical system is shown, and the distortion percentage is controlled to be about ± 1%.

Referring to fig. 4, the relative illuminance curve of the optical system can comprehensively reflect the imaging quality of the system, and the smoother the curve shape and the higher the height relative to the X axis, prove that the imaging quality of the system is better, and the lens has higher definition.

Example 2

In this embodiment, except for the claims, the fifth lens element has negative refractive power, the object-side surface is convex and the image-side surface is concave; the sixth lens element has positive refractive power, and has a concave object-side surface and a convex image-side surface.

The design parameters of the lens are shown in tables 4 and 5:

table 4:

table 5:

the corresponding parameters in this example are shown in table 6:

table 6:

referring to fig. 5, the lenses of the optical system are relatively symmetrical in shape, so that the optical system is convenient for molding production, and the lenses are reasonable in spacing and convenient for later structural design;

referring to fig. 6, the astigmatism of the illustrated optical system is controlled to be within ± 0.05.

Referring to fig. 7, the optical distortion curve of the optical system is shown with the distortion percentage controlled to be in the range of 2%.

Referring to fig. 8, the relative illuminance curve of the optical system can comprehensively reflect the imaging quality of the system, and the smoother the curve shape and the higher the height relative to the X axis, prove that the imaging quality of the system is better, and the lens has higher definition.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the scope of the present invention, which is defined by the appended claims.

Claims (3)

1. A high-pixel telephoto lens system includes a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, and a sixth lens element sequentially disposed from an object side to an image side along an optical axis, wherein:

the first lens has positive refractive power, and the object side surface of the first lens is a convex surface; the second lens has positive refractive power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the third lens has negative refractive power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the fourth lens has negative refractive power, the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a concave surface; the fifth lens has a negative refractive power; a diaphragm is arranged in front of the first lens, all surfaces of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are aspheric and plastic lenses, and the following conditions are met:

TTL/F<0.6

wherein, TTL is the optical total length of the optical system of the high-pixel telescopic lens; f is the focal length of the optical system;

0.25<T34/TTL<0.5

wherein T34 is an air space on the optical axis between the third lens and the fourth lens;

0<∣F4/F∣<0.3

where F4 is the focal length of the fourth lens.

2. The high-pixel telephoto lens according to claim 1, wherein an optical system of the high-pixel telephoto lens further satisfies the following condition:

TTL/IH<4.2

wherein IH is half image height.

3. The high-pixel telephoto lens system according to claim 1, wherein the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, and the sixth lens element are even-order aspheric plastic lenses, and aspheric coefficients satisfy the following equation:

wherein Z is an aspheric sagittal height, c is an aspheric paraxial curvature, y is a lens aperture, k is a conic coefficient, a4 is a 4-th aspheric coefficient, a6 is a 6-th aspheric coefficient, A8 is an 8-th aspheric coefficient, a10 is a 10-th aspheric coefficient, a12 is a 12-th aspheric coefficient, a14 is a 14-th aspheric coefficient, a16 is a 16-th aspheric coefficient, a18 is an 18-th aspheric coefficient, and a20 is a 20-th aspheric coefficient.

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