CN213934367U

CN213934367U - Optical lens

Info

Publication number: CN213934367U
Application number: CN202022844902.7U
Authority: CN
Inventors: 罗杰; 黄锦煖; 胡青平; 陈训安; 丁凤
Original assignee: Fujian Forecam Tiantong Optics Co Ltd
Current assignee: Fujian Forecam Tiantong Optics Co Ltd
Priority date: 2020-12-02
Filing date: 2020-12-02
Publication date: 2021-08-10
Anticipated expiration: 2030-12-02

Abstract

The invention relates to an optical lens, wherein a first lens, a diaphragm, a second lens, a third lens, a fourth lens, an optical filter and protective glass are sequentially arranged in an optical system of the lens along the incident direction of light rays from left to right, the first lens is a biconvex positive lens, the second lens is a biconcave negative lens, the third lens is a meniscus positive lens, and the fourth lens is a meniscus positive lens.

Description

Optical lens

Technical Field

The present invention relates to an optical lens.

Background

More than 50% of traffic accidents on the expressway are caused by inattention due to fatigue caused by long-distance driving or monotonous seen templates. There are many research units currently conducting research on driver monitoring techniques. The existing fatigue driving recognition system is based on facial features, eye signals and the like for judgment, but due to ambient light in a vehicle, glasses reflection and the like, the recognition error rate can be increased by imaging in a visible light range. Therefore, it is necessary to design a high-definition camera lens based on near infrared for driver face monitoring aiming at fatigue driving. At present, the defects of more lenses and larger volume exist in a lens for monitoring the face of a driver.

Disclosure of Invention

In view of the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide an optical lens.

In order to solve the technical problems, the technical scheme of the invention is as follows: the utility model provides an optical lens, be equipped with first lens, diaphragm, second lens, third lens, fourth lens, light filter, protective glass in proper order along the left right incident direction of light in the optical system of camera lens, first lens are biconvex positive lens, and the second lens are biconcave negative lens, and the third lens are meniscus positive lens, and the fourth lens are meniscus positive lens.

Further, the air space between the first lens and the second lens is 0.6-1mm, the air space between the second lens and the third lens is 0.2-0.4mm, and the air space between the third lens and the fourth lens is 0-0.2 mm.

Furthermore, the first lens, the second lens, the third lens and the fourth lens are all spherical lenses made of glass materials.

Further, the focal length of the optical system is

The focal lengths of the first lens, the second lens, the third lens and the fourth lens are respectively

、

、

、

Wherein

、

、

、

And

the following proportions are satisfied: 1.0<

/

<1.5，-1.7<

/

<-0.5，1.0<

/

<2.1，1.5<

/

<2.3。

Further, the first lens satisfies the relation:

≥1.8，

less than or equal to 55; the second lens satisfies the relation:

≥1.5，

not less than 40; the third lens satisfies the relation:

≥1.8，

less than or equal to 50; the fourth lens satisfies the relation:

≥1.7，

less than or equal to 50; wherein

In order to be the refractive index,

abbe constant.

Further, an optical total length TTL of the optical system and a focal length F of the optical system satisfy: TTL/F is less than or equal to 4.

Compared with the prior art, the invention has the following beneficial effects: the structure is simple, the design is reasonable, 4 full-glass spherical lenses are adopted, the overall reliability is high, the assembly sensitivity of the lens group is low, the yield is high, the number of lenses is small, the cost is low, the large-scale production is facilitated, the distortion is low, the imaging quality is high, and the 4k pixel high-definition camera shooting level is reached.

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

Drawings

FIG. 1 is a schematic view of an optical system of the lens barrel;

FIG. 2 is a graph of the visible light MTF of the lens;

FIG. 3 is a graph showing axial chromatic aberration of the lens;

fig. 4 is a lateral chromatic aberration diagram of the lens.

In the figure: 1-a first lens; 2-a diaphragm; 3-a second lens; 4-a third lens; 5-a fourth lens; 6-an optical filter; 7-protective glass; 8-imaging plane.

Detailed Description

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

As shown in fig. 1, an optical lens assembly is provided, in an optical system of the lens assembly, a first lens 1, a diaphragm 2, a second lens 3, a third lens 4, a fourth lens 5, an optical filter 6, and a cover glass 7 are sequentially disposed along a left-to-right incident direction of light, the first lens is a biconvex positive lens, both an object-side surface and an image-side surface of the first lens are convex surfaces, the second lens is a biconcave negative lens, both an object-side surface and an image-side surface of the second lens are concave surfaces, the third lens is a meniscus positive lens, both an object-side surface and an image-side surface of the third lens are convex surfaces, the fourth lens is a meniscus positive lens, both an object-side surface and an image-side surface of the fourth lens are convex surfaces.

In this embodiment, the air space between the first lens and the second lens is 0.6-1mm, the air space between the second lens and the third lens is 0.2-0.4mm, and the air space between the third lens and the fourth lens is 0-0.2 mm.

In this embodiment, the first lens, the second lens, the third lens and the fourth lens are all spherical lenses made of glass.

In this embodiment, the focal length of the optical system is

、

、

、

Wherein

、

、

、

And

the following proportions are satisfied: 1.0<

/

<1.5，-1.7<

/

<-0.5，1.0<

/

<2.1，1.5<

/

<2.3, reasonably distributing the focal power of the optical system according to the proportion, wherein each lens is relative to the focal length of the system

In a certain proportion, the aberration of the optical system formed by the invention in the wavelength range of 950 +/-25 nm is reasonably corrected and balanced.

In this embodiment, the first lens satisfies the following relation:

≥1.8，

less than or equal to 55; the second lens satisfies the relation:

≥1.5，

not less than 40; the third lens satisfies the relation:

≥1.8，

less than or equal to 50; the fourth lens satisfies the relation:

≥1.7，

less than or equal to 50; wherein

In order to be the refractive index,

abbe constant.

In this embodiment, the total optical length TTL of the optical system and the focal length F of the optical system satisfy: TTL/F is less than or equal to 4.

The specific parameters of each lens are as follows:

in this embodiment, the technical indexes achieved by the optical system are as follows:

(1) focal length: EFFL =5.18 mm; (2) aperture F = 2.5; (3) the field angle: 2w is more than or equal to 46 degrees; (4) optical distortion: less than 3 percent; (5) the diameter of the imaging circle is larger than phi 4.8; (6) the working wave band is as follows: 940 +/-25 nm; (7) the total optical length TTL is less than or equal to 10mm, and the optical back intercept BFL is more than or equal to 1.3 mm; (8) the lens is suitable for a 4k pixel CCD or CMOS camera.

As can be seen from FIG. 2, the MTF of the optical system in the visible light band is well represented, the MTF value of the edge field at the spatial frequency of 111pl/mm is greater than 0.4, the MTF value of the center field at the spatial frequency of 111pl/mm is greater than 0.6, and the resolution requirement of 4K high definition can be achieved. As can be seen from FIGS. 3 and 4, the axial chromatic aberration of the optical system is less than 0.02mm, and the transverse chromatic aberration is well corrected within the range of Airy spots. In conclusion, the optical system has excellent imaging quality and completely meets the requirement of 4k pixel shooting.

This camera lens adopts 4 full glass sphere structures of formula, compares in common on-vehicle optics night vision system, and the number of film is still less, and the cost is lower.

The lens has the advantages that through reasonable glass material collocation and lens optical power distribution, the axial chromatic aberration and the transverse chromatic aberration of the whole optical system are well corrected, the high-grade chromatic aberration of the whole optical system is effectively corrected through reasonable surface design, meanwhile, the light incidence angle of each mirror surface is small, and the overall imaging quality of the system is excellent.

It should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that: modifications to the specific embodiments of the invention or equivalent substitutions for parts of the technical features may be made; without departing from the spirit of the present invention, it is intended to cover all aspects of the invention as defined by the appended claims.

Claims

1. An optical lens, characterized in that: the optical system of the lens is sequentially provided with a first lens, a diaphragm, a second lens, a third lens, a fourth lens, an optical filter and protective glass along the incident direction of light rays from left to right, wherein the first lens is a biconvex positive lens, the second lens is a biconcave negative lens, the third lens is a meniscus positive lens, and the fourth lens is a meniscus positive lens.

2. An optical lens according to claim 1, characterized in that: the air space between the first lens and the second lens is 0.6-1mm, the air space between the second lens and the third lens is 0.2-0.4mm, and the air space between the third lens and the fourth lens is 0-0.2 mm.

3. An optical lens according to claim 1, characterized in that: the first lens, the second lens, the third lens and the fourth lens are all spherical lenses made of glass materials.

4. An optical lens according to claim 1, characterized in that: the focal length of the optical system is

、

、

、

Wherein

、

、

、

And

the following proportions are satisfied: 1.0<

/

<1.5，-1.7<

/

<-0.5，1.0<

/

<2.1，1.5<

/

<2.3。

5. An optical lens according to claim 1, characterized in that: the first lens satisfies the relation:

≥1.8，

less than or equal to 55; the second lens satisfies the relation:

≥1.5，

not less than 40; the third lens satisfies the relation:

≥1.8，

less than or equal to 50; the fourth lens satisfies the relation:

≥1.7，

less than or equal to 50; wherein

In order to be the refractive index,

abbe constant.

6. An optical lens according to claim 1, characterized in that: the total optical length TTL of the optical system and the focal length F of the optical system meet the following conditions: TTL/F is less than or equal to 4.