CN115166948B

CN115166948B - Low-cost glass-plastic hybrid monitoring lens and electronic equipment

Info

Publication number: CN115166948B
Application number: CN202210898653.0A
Authority: CN
Inventors: 杨成林; 安宁; 孙振中; 杨井留; 吴喆明; 罗艳波
Original assignee: Sirtec International Suzhou Co ltd
Current assignee: Sirtec International Suzhou Co ltd
Priority date: 2022-07-28
Filing date: 2022-07-28
Publication date: 2023-09-29
Anticipated expiration: 2042-07-28
Also published as: CN115166948A

Abstract

The invention discloses a low-cost glass-plastic mixed monitoring lens and electronic equipment, wherein the lens comprises a first lens, a second lens, a third lens and a filter disc which are sequentially arranged along an optical axis from left to right in an incident direction, the first lens has positive focal power, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, the second lens has positive focal power, the object side surface of the second lens is a concave surface, the image side surface of the second lens is a convex surface, the third lens has negative focal power, the object side surface of the third lens is a concave surface or a convex surface, and the image side surface of the third lens is a convex surface or a concave surface. The invention adopts 1 glass spherical lens and 2 plastic aspherical lenses, has simple assembly, low cost, high resolution, high relative illumination, distortion less than or equal to-6 percent, head size less than or equal to 7.5mm, optical length less than or equal to 8.5mm, small volume, contribution to module miniaturization, and overcomes the defects of large volume, large distortion, high cost of full glass or 1G3P, complex assembly, low resolution, low relative illumination and the like in the prior art, thereby being suitable for industrialized popularization and use.

Description

Low-cost glass-plastic hybrid monitoring lens and electronic equipment

Technical Field

The invention belongs to the technical field of optical imaging, and particularly relates to a low-cost glass-plastic hybrid monitoring lens and electronic equipment.

Background

With the rapid development and wide application of intelligent auxiliary driving systems, the requirements for monitoring the automobile condition and the driving state of a driver are continuously improved, and in order to improve the capture of the facial expression state of the driver, the monitoring lens with the advantages of instant and accurate fatigue driving warning, high resolution, large aperture, small distortion, small volume and low cost is increasingly popular with people. The existing driver state monitoring lenses are of various types, but most of the existing driver state monitoring lenses have the following problems: the structure is complex, most of the structures are 4G or 1G3P, the volume is large, the head size is more than or equal to 8mm, the optical total length is more than or equal to 12mm, the assembly is complex, and the cost is high.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention aims to provide a low-cost glass-plastic hybrid monitoring lens and electronic equipment.

In order to achieve the above purpose and achieve the above technical effects, the invention adopts the following technical scheme:

the utility model provides a low-cost glass is moulded and is mixed monitoring lens, includes along the optical axis from left to right incidence direction first lens, second lens, third lens and filter element that set gradually, first lens has positive focal power, and its object side is the convex surface, and the image side is the concave surface, and the second lens has positive focal power, and its object side is the concave surface, and the image side is the convex surface, and the third lens has negative focal power, and its object side is concave surface or convex surface, and the image side is convex surface or concave surface.

Further, the refractive index Nd1 of the first lens is more than 1.85, and the Abbe number Vd1 is less than 45; the refractive index Nd2 of the second lens is more than 1.52, and the Abbe number Vd2 satisfies: vd2 is 54 < 58; the refractive index Nd3 of the third lens satisfies: 1.68 > Nd3 > 1.6, abbe number Vd3 satisfies: 25 > Vd3 > 20.

Further, the focal lengths f1, f2, f3 of the first lens L1, the second lens L2, and the third lens L3 and the focal length f of the entire group of lenses satisfy the condition:

0.6≤f1/f≤1.5，0.3≤f2/f≤0.7，-0.8≤f3/f≤-0.2。

further, the first lens is a first positive meniscus lens, the second lens is a second positive meniscus lens, the third lens is a third negative meniscus lens, and a diaphragm is arranged between the first lens and the second lens.

Further, the lens satisfies the condition:

0.4＞BFL/TTL＞0.25

BFL is the distance between the center of the image side surface of the last lens of the lens and the imaging surface of the lens on the optical axis; TTL is the distance on the optical axis from the center of the object side of the first lens to the imaging surface of the lens.

Further, the total focal length f of the lens and the distance TTL between the center of the object side surface of the first lens and the imaging surface of the lens on the optical axis satisfy the following conditions:

TTL/f≤1.7。

further, the lens satisfies the condition:

2.8≤FOV/h/D≤4.8

wherein, FOV is the maximum half field angle of the lens; d is the maximum aperture of the first lens object side corresponding to the maximum field angle of the lens; h is the image height corresponding to the maximum field angle of the lens.

Further, the maximum half field angle FOV of the lens, the whole group focal length f of the lens, and the image height h corresponding to the maximum field angle of the lens satisfy:

52≤(FOV×f)/h≤55。

further, the total length of the lens is smaller than 8.5mm, and the light transmission caliber of the first lens is smaller than 3.18mm.

An electronic device comprises the low-cost glass-plastic hybrid monitoring lens.

Compared with the prior art, the invention has the beneficial effects that:

the invention discloses a low-cost glass-plastic mixed monitoring lens and electronic equipment, wherein the lens comprises a first lens, a second lens, a third lens and a filter disc which are sequentially arranged along an optical axis from left to right in an incident direction, the first lens has positive focal power, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, the second lens has positive focal power, the object side surface of the second lens is a concave surface, the image side surface of the second lens is a convex surface, the third lens has negative focal power, the object side surface of the third lens is a concave surface or a convex surface, and the image side surface of the third lens is a convex surface or a concave surface. In the invention, the first lens is a glass spherical lens, the second lens and the third lens are plastic aspherical lenses, the assembly is simple, the cost is low, the resolution is high, the relative illuminance is high, the distortion is less than or equal to-6%, the head size is less than or equal to 7.5mm, the optical length is less than or equal to 8.5mm, the size is small, the miniaturization of the module is facilitated, and the defects of large size, large distortion, high cost of full glass or 1G3P, complex assembly, low resolution, low relative illuminance and the like in the prior art are overcome, so that the invention is suitable for industrialized popularization and use.

Drawings

Fig. 1 is a schematic structural view of embodiment 1 and embodiment 2 of the present invention;

FIG. 2 is a graph showing field curvature distortion in example 1 of the present invention;

FIG. 3 is a graph of MTF defocus for example 1 of the present invention;

FIG. 4 is a graph showing the relative illuminance of embodiment 1 of the present invention;

FIG. 5 is a graph showing field curvature distortion in example 2 of the present invention;

FIG. 6 is a graph of MTF defocus for example 2 of the present invention;

FIG. 7 is a graph showing the relative illuminance according to embodiment 2 of the present invention;

FIG. 8 is a schematic structural diagram of embodiment 3 of the present invention;

FIG. 9 is a graph showing field curvature distortion in example 3 of the present invention;

FIG. 10 is a graph of MTF defocus for example 3 of the present invention;

fig. 11 is a graph of relative illuminance in example 3 of the present invention.

Detailed Description

The present invention is described in detail below so that advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making clear and unambiguous the scope of the present invention.

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

As shown in fig. 1-11, a low-cost glass-plastic hybrid monitoring lens includes a first lens L1, a second lens L2, a third lens L3 and a filter L4 sequentially arranged along an optical axis in a left-to-right incidence direction, wherein the first lens L1 adopts a glass spherical lens, the second lens L2 and the third lens L3 adopt plastic aspheric lenses, the first lens L1 has positive focal power, an object side surface S1 is a convex surface, an image side surface S2 is a concave surface, the second lens L2 has positive focal power, an object side surface S4 is a concave surface, an image side surface S5 is a convex surface, the third lens L3 has negative focal power, an object side surface S6 is a concave surface or a convex surface, the image side surface S7 is a convex surface or a concave surface, the filter L4 has an object side surface S8 and an image side surface S9, and an imaging surface S10 is arranged on the right side of the filter L4.

The refractive index Nd1 of the first lens L1 is more than 1.85, and the Abbe number Vd1 is less than 45; the refractive index Nd2 of the second lens L2 > 1.52, and the abbe number Vd2 satisfies: vd2 is 54 < 58; the refractive index Nd3 of the third lens L3 satisfies: 1.68 > Nd3 > 1.6, abbe number Vd3 satisfies: 25 > Vd3 > 20.

And a diaphragm L5 is arranged between the first lens L1 and the second lens L2, so that the aperture of the lens is reduced.

The low-cost glass-plastic mixed monitoring lens provided by the invention meets the following conditions:

0.4＞BFL/TTL＞0.25

BFL is the distance between the center of the image side surface of the last lens of the lens and the imaging surface S10 of the lens on the optical axis; TTL is the distance between the center of the object side surface S1 of the first lens L1 and the imaging surface S10 of the lens on the optical axis, and further BFL/TTL is more than 0.3, so that the optical back focus of the lens can be increased, and sufficient space is reserved for the module.

The low-cost glass-plastic mixed monitoring lens can also meet the following conditions:

the FOV/h/D is more than or equal to 2.8 and less than or equal to 4.8, which is beneficial to realizing small caliber of the front-end lens;

wherein, FOV is the maximum half field angle of the lens; d is the maximum aperture of the object side S1 of the first lens L1 corresponding to the maximum field angle of the lens; h is the image height corresponding to the maximum field angle of the lens.

The maximum half field angle FOV of the low-cost glass-plastic hybrid monitoring lens, the whole group focal length value f of the lens and the image height h corresponding to the maximum field angle of the lens satisfy the following conditions:

the FOV multiplied by f/h is more than or equal to 52 and less than or equal to 55, and the three indexes are controlled, so that the lens distortion is reduced.

TTL/f is less than or equal to 1.7, and further, TTL/f is less than or equal to 1.5, so that the lens miniaturization is facilitated.

The focal lengths f1, f2, f3 of the first lens L1, the second lens L2, and the third lens L3 satisfy the condition:

0.6≤f1/f≤1.5，0.3≤f2/f≤0.7，-0.8≤f3/f≤-0.2

by reasonably matching the focal length of the lens, the assembly sensitivity is reduced, the Jiao Piaoyi of the lens at high and low temperatures is controlled in a small range, and clear imaging is achieved.

The total length of the lens is smaller than 8.5mm, the light transmission caliber of the first lens L1 is smaller than 3.18mm, and the lens has smaller volume and is more beneficial to miniaturization of the module.

As a specific implementation mode, the first lens L1 is a first positive meniscus lens, and the first lens L1 is of a meniscus structure, so that light is collected, distortion is reduced, and imaging quality is improved; the second lens L2 is a second meniscus positive lens, which is favorable for receiving the folded light more smoothly, reducing aberration, reducing sensitivity of the lens and reducing aperture of the lens; the third lens L3 is a third meniscus negative lens, which is favorable for correcting aberration and improving imaging quality.

Example 1

As shown in fig. 1-4, a low-cost glass-plastic hybrid monitoring lens includes a first lens L1, a second lens L2, a third lens L3 and a filter L4 sequentially arranged along an optical axis in a left-to-right incident direction, wherein the first lens L1 adopts a glass spherical lens, the second lens L2 and the third lens L3 adopt plastic aspheric lenses, the first lens L1 has positive focal power, an object side surface S1 is a convex surface, an image side surface S2 is a concave surface, the second lens L2 has positive focal power, an object side surface S4 is a concave surface, an image side surface S5 is a convex surface, the third lens L3 has negative focal power, an object side surface S6 is a concave surface, an image side surface S7 is a convex surface, the filter L4 has an object side surface S8 and an image side surface S9, and an imaging surface S10 is arranged on the right side of the filter L4.

The first lens L1 is a first meniscus positive lens, and the first lens L1 is of a meniscus structure, so that light rays can be collected, distortion is reduced, and imaging quality is improved; the second lens L2 is a second meniscus positive lens, which is favorable for receiving the folded light more smoothly, reducing aberration, reducing sensitivity of the lens and reducing aperture of the lens; the third lens L3 is a third meniscus negative lens, which is favorable for correcting aberration and improving imaging quality.

The optical parameters of the first lens L1, the second lens L2, the third lens L3, the filter L4, and the stop L5 are shown in table 1.

TABLE 1

In table 1, the radii of curvature of the surfaces of the filter L4, the diaphragm L5, and the image plane IMA are infinite, indicating that the surfaces are planar.

Each aspherical surface type Z is described as follows:

where z is a position of the aspherical surface at a height R in the optical axis direction, a distance vector from the vertex of the aspherical surface is high, c is a curvature of the paraxial of the aspherical surface, c=1/R, R is a radius of curvature, c is an inverse of the radius of curvature, k is a conic coefficient, α1 is an aspherical 2 nd order coefficient, α2 is an aspherical 4 th order coefficient, α3 is an aspherical 6 th order coefficient, α4 is an aspherical 8 th order coefficient, α5 is an aspherical 10 th order coefficient, α6 is an aspherical 12 th order coefficient, α7 is an aspherical 14 th order coefficient, and α8 is an aspherical 16 th order coefficient.

Table 2 below shows the cone coefficients k and the higher order coefficients α2, α3, α4, α5, α6, α7, α8 that can be used for the lens surfaces S5, S6, S7, S8 in embodiment 1.

TABLE 2

Face number

k

α2

α3

α4

α5

α6

α7

α8

S5

6.00E+00

2.39E-03

-1.54E-02

1.05E-02

-3.36E-03

1.06E-04

1.74E-04

-2.77E-05

S6

-3.77E+00

-3.89E-02

8.04E-03

-6.08E-04

-2.63E-04

8.36E-05

-1.14E-05

6.41E-07

S7

4.43E+00

-6.60E-02

6.28E-03

2.96E-03

-1.34E-03

1.72E-04

-1.72E-06

-1.04E-06

S8

-4.33E+00

-5.05E-02

1.57E-02

-3.69E-03

5.76E-04

-6.05E-05

3.78E-06

-1.05E-07

Example 2

As shown in fig. 1 and fig. 5-7, a low-cost glass-plastic hybrid monitoring lens includes a first lens L1, a second lens L2, a third lens L3 and a filter L4 sequentially disposed along an optical axis in a left-to-right incident direction, wherein the first lens L1 has positive optical power, an object side surface S1 is a convex surface, an image side surface S2 is a concave surface, the second lens L2 has positive optical power, an object side surface S4 is a concave surface, an image side surface S5 is a convex surface, the third lens L3 has negative optical power, an object side surface S6 is a concave surface, an image side surface S7 is a convex surface, the filter L4 has an object side surface S8 and an image side surface S9, and an imaging surface S10 is disposed on the right side of the filter L4.

The optical parameters of the first lens L1, the second lens L2, the third lens L3, the filter L4, and the stop L5 are shown in table 3.

TABLE 3 Table 3

Table 4 below shows the cone coefficients k and the higher order coefficients α2, α3, α4, α5, α6, α7, α8 of the lens surfaces S4, S5, S6, S7 that can be used in embodiment 2.

TABLE 4 Table 4

Example 1 was followed.

Example 3

As shown in fig. 8-11, a low-cost glass-plastic hybrid monitoring lens includes a first lens L1, a second lens L2, a third lens L3 and a filter L4 sequentially disposed along an optical axis in a left-to-right incident direction, wherein the first lens L1 has positive optical power, an object side surface S1 is a convex surface, an image side surface S2 is a concave surface, the second lens L2 has positive optical power, an object side surface S4 is a concave surface, an image side surface S5 is a convex surface, the third lens L3 has negative optical power, an object side surface S6 is a convex surface, an image side surface S7 is a concave surface, the filter L4 has an object side surface S8 and an image side surface S9, and an imaging surface S10 is disposed on the right side of the filter L4.

The optical parameters of the first lens L1, the second lens L2, the third lens L3, the filter L4, and the stop L5 are shown in table 5.

TABLE 5

Table 6 below shows the cone coefficients k and the higher order coefficients α2, α3, α4, α5, α6, α7, α8 of the lens surfaces S4, S5, S6, S7 that can be used in embodiment 3.

TABLE 6

Example 1 was followed.

Fig. 2 is a field curvature distortion chart of embodiment 1 of the present invention, fig. 5 is a field curvature distortion chart of embodiment 2 of the present invention, fig. 9 is a field curvature distortion chart of embodiment 3 of the present invention, wherein a graph a in the field curvature distortion chart is a field curvature chart, an ordinate of the field curvature chart is a field angle, an abscissa is a distance of an image point from a paraxial image plane, T represents a meridian field curvature, S represents a sagittal field curvature, the field curvature chart shows a current focal plane or a distance of an image plane from the paraxial focal plane as a function of a field-of-view coordinate, and is divided into a meridian field curvature and a sagittal field curvature, a graph B is a distortion chart, an ordinate of the distortion chart is a field angle, an abscissa is a distortion percentage, and the distortion belongs to a chief ray aberration reflecting a degree of similarity of an object. It can be seen that the lenses of examples 1-3 have less optical distortion and clear images.

Fig. 3 is an MTF defocus graph of embodiment 1 of the present invention, fig. 6 is an MTF defocus graph of embodiment 2 of the present invention, and fig. 10 is an MTF defocus graph of embodiment 3 of the present invention, wherein the ordinate in the MTF defocus graph is the MTF value, the abscissa is the distance of an image point from a paraxial image plane, and the MTF defocus graph of a lens reflects the resolution of the lens. It can be seen that the lens of examples 1-3, which has a concentrated MTF defocus curve of 83LP and a high MTF value, can reflect the high resolution of the lens and clear imaging.

Fig. 4 is a relative illuminance map of embodiment 1 of the present invention, fig. 7 is a relative illuminance map of embodiment 2 of the present invention, fig. 11 is a relative illuminance map of embodiment 3 of the present invention, the ordinate of the relative illuminance map is an illuminance value, the abscissa is a view angle, and the relative illuminance map of the lens reflects the degree of uniformity of the screen illuminance of the lens. It can be seen that the lens of the embodiments 1-3 has a relative illuminance greater than 0.6 at the maximum field angle, which reflects that the lens has a higher relative illuminance and a better uniformity of the illuminance of the picture.

Parts or structures of the present invention, which are not specifically described, may be existing technologies or existing products, and are not described herein.

The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the invention, and all equivalent structures or equivalent processes or direct or indirect application in other related arts are included in the scope of the present invention.

Claims

1. The low-cost glass-plastic hybrid monitoring lens is characterized by comprising a first lens, a second lens, a third lens and a filter disc which are sequentially arranged along an optical axis from left to right in an incident direction, wherein the first lens has positive focal power, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, the second lens has positive focal power, the object side surface of the second lens is a concave surface, the image side surface of the second lens is a convex surface, the third lens has negative focal power, the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface;

the focal lengths f1, f2, f3 of the first lens L1, the second lens L2 and the third lens L3 and the whole set of focal length values f of the lenses satisfy the condition:

0.6≤f1/f≤1.5，0.3≤f2/f≤0.7，-0.8≤f3/f≤-0.2；

the lens satisfies the condition:

0.4＞BFL/TTL＞0.25

BFL is the distance between the center of the image side surface of the last lens of the lens and the imaging surface of the lens on the optical axis; TTL is the distance between the center of the object side surface of the first lens and the imaging surface of the lens on the optical axis;

the lens satisfies the condition:

2.8≤FOV/h/D≤4.8

wherein, FOV is the maximum half field angle of the lens; d is the maximum aperture of the first lens object side corresponding to the maximum field angle of the lens; h is the image height corresponding to the maximum field angle of the lens;

the maximum half field angle FOV of the lens, the whole group focal length value f of the lens and the image height h corresponding to the maximum field angle of the lens satisfy the following conditions:

52≤(FOV×f)/h≤55；

the distortion of the lens is less than or equal to-6%, the head size is less than or equal to 7.5mm, and the optical length is less than or equal to 8.5mm; the aperture of the first lens is smaller than 3.18mm.

2. The low-cost glass-plastic hybrid monitoring lens according to claim 1, wherein the refractive index Nd1 of the first lens is more than 1.85, and the abbe number Vd1 is less than 45; the refractive index Nd2 of the second lens is more than 1.52, and the Abbe number Vd2 satisfies: vd2 is 54 < 58; the refractive index Nd3 of the third lens satisfies: 1.68 > Nd3 > 1.6, abbe number Vd3 satisfies: 25 > Vd3 > 20.

3. The low-cost glass-plastic hybrid monitoring lens according to claim 1, wherein the first lens is a first positive meniscus lens, the second lens is a second positive meniscus lens, the third lens is a third negative meniscus lens, and a diaphragm is arranged between the first lens and the second lens.

4. The low-cost glass-plastic hybrid monitoring lens according to claim 1, wherein the whole set of focal length values f of the lens and the distance TTL from the center of the object side surface of the first lens to the imaging surface of the lens on the optical axis satisfy the condition:

TTL/f≤1.7。

5. an electronic device comprising a low cost glass-plastic hybrid monitoring lens as defined in any one of claims 1-4.