CN109814237B

CN109814237B - DMS wide-angle camera lens and camera system

Info

Publication number: CN109814237B
Application number: CN201910203191.4A
Authority: CN
Inventors: 成一诺; 李林
Original assignee: Beijing Jingwei Hirain Tech Co Ltd
Current assignee: Beijing Jingwei Hirain Tech Co Ltd
Priority date: 2019-03-18
Filing date: 2019-03-18
Publication date: 2021-05-18
Anticipated expiration: 2039-03-18
Also published as: CN109814237A

Abstract

The invention provides a DMS wide-angle camera lens and a camera system, the DMS wide-angle camera lens comprises a first lens group with negative focal power and a second lens group with positive focal power, the first lens group and the second lens group form a reverse telephoto type structure, the first lens and the second lens are spherical negative lenses, the curvature radius of each surface of the first lens and the second lens is limited, when the camera lens is applied to different CMOS photosensitive chips, the shapes of the first lens and the second lens can not be changed, only the air space between the first lens and the second lens is changed, and the lenses in the second lens group are matched, so that the first lens and the second lens can be shared in different lenses, when the CMOS chips are replaced, the processing molds of the first lens and the second lens can also be used, the sharing of the first lens and the second lens in the camera lens is improved, the processing cost is reduced to a certain extent.

Description

DMS wide-angle camera lens and camera system

Technical Field

The invention relates to the technical field of optical imaging, in particular to a Driver Monitoring (DMS) wide-angle camera lens which is applied to Driver Monitoring; and a DMS wide-angle imaging system.

Background

The driver monitoring system transmits the real-time image of the driver to the CMOS photosensitive chip by using the DMS monitoring camera, and processes the real-time image of the driver to detect the real-time attention of the driver.

The field angle of the existing lens for monitoring the driver is below 60 degrees, and the technical scheme of the existing lens mainly has the following structural forms: (1): 5 glass lenses (5G), (2): 4 glass lenses plus 1 plastic aspheric lens (4G1P), (3): 3 glass lenses plus 2 plastic aspheric lenses (3G 2P). Since it is very difficult to process the surface of the glass lens into an aspheric surface, the glass lens is usually made into a spherical surface, i.e. both surfaces of the glass lens are spherical surfaces with rotational symmetry, while the rest of the plastic lens can be processed into an aspheric surface.

In the prior art, the design of a lens is designed specifically for a specific CMOS photosensitive chip, and if the CMOS photosensitive chip is replaced, the lens needs to be redesigned for the replaced CMOS photosensitive chip, which results in poor sharing performance of the lens and high processing cost.

Disclosure of Invention

In view of this, the present invention provides a DMS wide-angle camera lens and a camera system, so as to solve the problems of the prior art, such as poor lens sharing and high processing cost.

In order to achieve the purpose, the invention provides the following technical scheme:

a DMS wide-angle camera lens, comprising:

the first lens group and the second lens group are sequentially arranged from the object side to the image side;

the first lens group is a negative focal power lens group, and the second lens group is a positive focal power lens group;

the first lens group includes: the lens comprises a first lens and a second lens which are sequentially arranged from an object space to an image space, wherein the first lens and the second lens are spherical negative lenses;

the first lens comprises a first surface close to an object side and a second surface close to an image side;

the second lens comprises a third surface close to the object side and a fourth surface close to the image side;

the first surface and the fourth surface are both convex surfaces, and the second surface and the third surface are both concave surfaces;

wherein the radius of curvature of the first surface ranges from: 4.3mm-4.5mm, inclusive;

the radius of curvature of the second surface ranges from: 2.3mm-2.5mm, inclusive;

the radius of curvature of the third surface ranges from: -4.0mm to-3.8 mm, inclusive;

the radius of curvature of the fourth surface ranges from: -4.2mm to-4.0 mm, inclusive.

Preferably, the second lens group includes: the third lens and the fourth lens are sequentially arranged from the object space to the image space;

the third lens is a spherical positive lens, and the fourth lens is an aspheric positive lens;

the third lens comprises a fifth surface close to the object side and a sixth surface close to the image side;

the fourth lens comprises a seventh surface close to the object side and an eighth surface close to the image side;

the fifth surface, the sixth surface and the eighth surface are convex surfaces, and the seventh surface is a concave surface.

Preferably, the aspherical surface type expression of the fourth lens is:

wherein

As radial coordinate, α₁～α₈The coefficient is a high-order aspheric coefficient, k is a quadric coefficient, c is 1/R and is curvature, and R is curvature radius;

the high-order aspheric surface coefficient is less than or equal to 10^-8Magnitude.

Preferably, the first lens, the second lens and the third lens are all glass lenses; the fourth lens is a plastic lens.

Preferably, the first lens and the second lens are made of H-LAK3 glass, the third lens is made of H-ZF52 glass, and the fourth lens is made of E48R.

Preferably, the radius of curvature of the first surface is 4.4mm, the radius of curvature of the second surface is 2.4mm, the radius of curvature of the third surface is-3.9 mm, and the radius of curvature of the fourth surface is-4.1 mm.

Preferably, the radius of curvature of the fifth surface is 3.08 mm; the radius of curvature of the sixth surface is-24.24 mm.

Preferably, the radius of curvature of the fifth surface is 4.14 mm; the radius of curvature of the sixth surface is-13.90 mm.

The present invention also provides a DMS wide-angle imaging system including:

the camera lens comprises a photosensitive chip and a camera lens positioned on the photosensitive side of the photosensitive chip;

the camera lens is the DMS wide-angle camera lens described in any one of the above items.

Preferably, the photosensitive chip includes: a CMOS photosensitive chip with the model number OV9284 and a CMOS photosensitive chip with the model number AR0135 AT.

As can be seen from the above technical solutions, the DMS wide-angle imaging lens according to the present invention includes: the first lens group and the second lens group with negative focal power form a reverse telephoto type structure, the first lens group and the second lens group are spherical negative lenses, the curvature radius of each surface of the first lens group and the second lens group is limited, so that the first lens group and the second lens group can be applied to different camera lenses, when the camera lenses are applied to different CMOS photosensitive chips, the shapes of the first lens group and the second lens group can be unchanged, only the air space between the first lens group and the second lens group is changed, and the lenses in the second lens group are matched, so that the first lens group and the second lens can be shared by different lenses, when the CMOS chips are replaced, the processing molds of the first lens group and the second lens can also be used, and the first lens group and the second lens group can be processed in a large batch at one time for different systems to use, so that the sharing performance of the first lens group and the second lens group in the camera lenses is improved, the processing cost is reduced to a certain extent.

Moreover, the first lens and the second lens are closer to an object space, the caliber is larger, and when the first lens and the second lens can be shared in different systems, the mold opening cost of the first lens and the second lens can be saved, and the processing cost is greatly reduced. Furthermore, the first lens and the second lens are spherical lenses, so that the processing is simpler.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a graph of the chief ray angle CRA required for an OV9284 photosensitive chip;

FIG. 2 is a graph of the required chief ray angle CRA of the AR0135AT photosensitive chip;

FIG. 3 is a schematic structural diagram of a DMS wide-angle camera lens for OV9284 chip according to an embodiment of the present invention;

FIG. 4 is a RMS plot of the wave aberration of a DMS wide-angle camera lens suitable for use with an OV9284 chip;

FIG. 5 is a distortion diagram of a DMS wide-angle camera lens suitable for use with an OV9284 chip;

FIG. 6 is a MTF graph of a DMS wide-angle camera lens suitable for use with an OV9284 chip;

FIG. 7 is a schematic structural diagram of a DMS wide-angle camera lens for an AR0135AT chip according to an embodiment of the present invention;

FIG. 8 is a RMS (root mean square) wave aberration diagram of a DMS wide-angle imaging lens suitable for use with an AR0135AT chip;

fig. 9 is a distortion diagram of a DMS wide-angle imaging lens suitable for an AR0135AT chip;

fig. 10 is an MTF graph of a DMS wide-angle imaging lens suitable for an AR0135AT chip.

Detailed Description

As described in the background section, lenses in the prior art have poor commonality, resulting in higher processing costs.

The inventors found that the reason for the above phenomenon is: when the lens is designed for one CMOS photosensitive chip, the imaging quality of the CMOS photosensitive chip is only guaranteed to meet the system requirements, when the lens is designed for another CMOS photosensitive chip, the imaging quality of the other CMOS photosensitive chip is guaranteed to meet the system requirements, the imaging quality requirements of the other CMOS photosensitive chip are not required to be considered, and therefore the design difficulty of the lens can be greatly reduced. If the imaging quality requirements of two CMOS photosensitive chips are simultaneously met, the design difficulty of the lens is increased sharply. In order to ensure simple design, the common property of the lens is poor, so that one set of lens can only be applied to one CMOS chip and can not be applied to CMOS chips of other models, and the processing cost of the lens is higher.

Based on this, the present invention provides a DMS wide-angle imaging lens including:

wherein the radius of curvature of the first surface ranges from: 4.3mm-4.5mm, inclusive; the radius of curvature of the second surface ranges from: 2.3mm-2.5mm, inclusive;

The DMS wide-angle camera lens provided by the invention comprises a first lens group with negative focal power and a second lens group with positive focal power, wherein the first lens group and the second lens group form a reverse telephoto type structure, the first lens and the second lens are spherical negative lenses, and the curvature radius of each surface of the first lens and the second lens is limited, so that the first lens and the second lens can be applied to different camera lenses, when the camera lens is applied to different CMOS photosensitive chips, the shapes of the first lens and the second lens are not changed, only the air space between the first lens and the second lens is changed, and the lenses in the second lens group are matched, so that the first lens and the second lens can be shared in different lenses, when the CMOS chips are replaced, the processing molds of the first lens and the second lens can be used continuously, and the first lens and the second lens can be processed at one time in a large batch for different systems, the sharing performance of the first lens and the second lens in the camera lens is improved, and the processing cost is reduced.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

An embodiment of the present invention provides a DMS wide-angle imaging lens, including: the first lens group and the second lens group are sequentially arranged from the object side to the image side; the first lens group is a negative focal power lens group, and the second lens group is a positive focal power lens group; the first lens group includes: the first lens and the second lens are arranged along the object space to the image space in sequence, and both the first lens and the second lens are spherical negative lenses; the first lens comprises a first surface close to the object side and a second surface close to the image side; the second lens comprises a third surface close to the object side and a fourth surface close to the image side; the first surface and the fourth surface are convex surfaces, and the second surface and the third surface are concave surfaces; wherein the radius of curvature of the first surface is in the range: 4.3mm-4.5mm, inclusive; the radius of curvature of the second surface ranges from: 2.3mm-2.5mm, inclusive; the radius of curvature of the third surface ranges from: -4.0mm to-3.8 mm, inclusive; the radius of curvature of the fourth surface ranges from: -4.2mm to-4.0 mm, inclusive.

It should be noted that, in an embodiment of the present invention, the radius of curvature of the first surface is 4.4mm, the radius of curvature of the second surface is 2.4mm, the radius of curvature of the third surface is-3.9 mm, and the radius of curvature of the fourth surface is-4.1 mm.

The present invention is not limited to the specific structure of the second lens group, and in one embodiment of the present invention, the second lens group includes: the third lens and the fourth lens are sequentially arranged from the object space to the image space; the third lens is a spherical positive lens, and the fourth lens is an aspheric positive lens; the third lens comprises a fifth surface close to the object side and a sixth surface close to the image side; the fourth lens comprises a seventh surface close to the object side and an eighth surface close to the image side; the fifth surface, the sixth surface and the eighth surface are convex surfaces, and the seventh surface is a concave surface.

It should be noted that the above concave surface of the present invention refers to a plane perpendicular to the optical axis passing through the intersection point of one surface of the lens and the optical axis, and the portion near the optical axis of the plane is located in the lens; the convex surface of the present invention means a plane perpendicular to the optical axis passing through the intersection of one surface of the lens and the optical axis, and a portion near the optical axis of the plane is located outside the lens.

Correspondingly, the radius of curvature of the fifth surface in one embodiment of the invention is 3.08 mm; the radius of curvature of the sixth surface is-24.24 mm. Another embodiment has a radius of curvature of the fifth surface of 4.14 mm; the radius of curvature of the sixth surface is-13.90 mm. The present invention is not limited to this, and those skilled in the art can perform fine adjustment on the curvature radius of the third lens according to the curvature radius settings of the first lens and the second lens, which is not limited in this embodiment.

In the embodiment of the present invention, the specific structure of the aspheric lens of the fourth lens is not limited, and in an embodiment of the present invention, the aspheric surface type expression of the fourth lens is as follows:

wherein

As radial coordinate, α₁～α₈The coefficient is a high-order aspheric coefficient, k is a quadric coefficient, c is 1/R and is curvature, and R is curvature radius; the high-order aspheric surface coefficient is less than or equal to 10^-8Magnitude.

In the prior art, both surfaces of the plastic lens are processed into aspheric surfaces, but the aspheric coefficient of the plastic lens in almost all the technical schemes is as high as 10^-14～10^-16Some even reach 10^-20Therefore, the requirement on the processing precision of the aspheric surface is high, and great difficulty is brought to aspheric surface processing. In the embodiment of the invention, the aspheric surface coefficient is controlled to be 10^-8In the order of up to 10^-8Thereby facilitating subsequent processing, debugging and detection.

Experiments prove that the optical requirements of the camera lens can be met by adopting 3 spherical lenses and 1 aspheric lens, the structure of the system is simplified, and the number of the lenses can be reduced compared with an optical system adopting 5 lenses in the prior art.

In the embodiment of the invention, the specific material of each lens is not limited, in order to further reduce the processing cost of the lens, the lens in the embodiment is mainly made of glass, and the manufacturing difficulty of processing the aspheric lens by using glass is very high, so that the first lens, the second lens and the third lens are optional in the embodiment and are all glass lenses; the fourth lens is a plastic lens. Further, in order to reduce the influence of temperature on the system, the plastic aspherical lens is placed as close as possible to the image side.

In consideration of the fact that common glass materials are adopted as much as possible, two common glasses, namely H-LAK3 and H-ZF52, are selected in the embodiment of the invention; specifically, the first lens and the second lens are made of H-LAK3 glass, the third lens is made of H-ZF52 glass, and the fourth lens is made of E48R.

In addition, the aspherical surface in the present embodiment passes through the aberration theory and uses Zemax softThe piece is subjected to deduction verification for multiple times, and the aspheric surface coefficient of the plastic aspheric lens only needs to reach 10^-8The processing precision of the plastic aspheric surface profile is greatly reduced, the processing and detection difficulty is greatly reduced, the requirements on a die and a processing instrument are also reduced, and the processing cost can be greatly reduced.

In this embodiment, the first lens group and the second lens group form a reverse telephoto type structure, the formed field angle can be large, and experiments prove that the field angle of the wide-angle imaging lens provided in the embodiment of the present invention can reach 80 °. In the embodiment, only 3 glass lenses and 1 plastic lens are adopted, so that the number of lenses of the whole system is reduced, the structure is greatly simplified, the requirements on processing, assembly and adjustment are low, and the cost is reduced.

And the reverse telephoto type structure is adopted, so that the angle between the off-axis light beam and the optical axis can be rapidly reduced, and the aberration can be corrected. In addition, in the embodiment of the invention, the aperture diaphragm can be moved to the third lens, and the exit pupil distance is controlled to be larger than a certain numerical value (only controlled to be 2.19 times of the absolute value of the focal length), so that the Angle of each field of view CRA (Chief Ray Angle) is reduced, the requirement can be met, and vignetting cannot be caused.

In the embodiment, the problem of matching requirement with the main ray angle CRA of the detector is considered, continuous calibration is performed according to the characteristics of materials and functions required to be realized, and finally, the incident angles of the rays on the surfaces are gradually reduced, so that the requirement of correcting aberration is met.

In the embodiment of the invention, two detectors, namely an OV9284 detector and an AR0135 detector, of a vehicle-scale CMOS photosensitive chip are taken as examples for detailed description. The main ray angle CRA required by the OV9284 photosensitive chip is shown in fig. 1, the abscissa is Image Height (Image Height) in mm, and the ordinate is CRA value in °; that is, the angle between the chief ray of each field of view and the optical axis cannot be larger than the values in table 1.

TABLE 1

In order to meet the requirements of the chief ray and the optical axis angle CRA under each view field, in this embodiment, the aperture stop is moved forward to the third lens, and the exit pupil distance is controlled to be larger than a certain value (the distance is controlled to be 2.19 times of the absolute value of the focal length), so that the angle of each view field CRA is reduced, and the requirements can be met.

The included angle CRA between the chief ray and the optical axis of the DMS wide-angle camera lens of the present invention under each field of view is shown in table 2:

TABLE 2

Field of view	Image height/mm	CRA value/°
			0	0	0
0.3	0.575	6.47
			0.5	1.125	11.22
0.7	1.575	16.32
			0.85	1.9	20.30
1	2.25	24.35

Therefore, for an optical system applied to the OV9284 photosensitive chip, the included angle CRA between the principal ray and the optical axis of the DMS wide-angle camera lens under each field of view is smaller than the angle value required by a detector photosensitive chip manufacturer, the requirements are met, and vignetting is avoided.

For the AR0135 detector photosensitive chip, the required chief ray angle CRA of the photosensitive chip is shown in fig. 2, the abscissa is the Image Height (Image Height) in mm, and the ordinate is the CRA value in ° in unit.

Similarly, in order to meet the requirements of the chief ray and the optical axis angle CRA in each field of view, the wide-angle DMS driver monitor lens of the present invention especially moves the aperture stop forward to the third lens, and controls the exit pupil distance to be greater than a certain value (only 2.19 times the absolute value of the focal length), so that the angle of each field of view CRA is reduced and the requirements can be met.

For the AR0135 detector photosensitive chip, the included angle CRA between the chief ray and the optical axis of the DMS wide-angle camera lens of the present invention at each field of view is shown in table 3:

TABLE 3

Field of view	Image height/mm	CRA value/°
			0	0.00	0
0.3	0.90	6.74
			0.5	1.50	11.64
0.7	2.10	16.87
			0.85	2.60	21.00
1	3.00	25.25

For an optical system applied to an AR0135 photosensitive chip, the included angle CRA between the principal ray and the optical axis of the DMS wide-angle camera lens under each field of view is smaller than the angle value required by a detector photosensitive chip manufacturer, the requirements are met, and vignetting cannot be caused.

Therefore, the DMS wide-angle camera lens carries out targeted design on the vehicle-scale CMOS photosensitive chip used for the driver monitoring system, so that the lens can perfectly match the CRA chief ray angle of the CMOS photosensitive chip.

In order to illustrate the beneficial effects of the DMS wide-angle imaging lens according to the present invention, the present invention will be described in detail by taking two CMOS photosensitive chips AR0135AT and OV9284 as examples, please refer to the following embodiments.

Example one

Referring to fig. 3, fig. 3 is a schematic structural diagram of a DMS wide-angle camera lens for an OV9284 chip according to an embodiment of the present invention; the DMS wide-angle camera lens for the OV9284 chip comprises a first lens 11, a second lens 12, a third lens 13 and a fourth lens 14 which are sequentially arranged from an object side to an image side, and after light is emitted from a system, the light is finally formed on an OV9284 type photosensitive chip 17 through an optical filter 15 and chip protective glass 16.

In this embodiment, the first lens 11, the second lens 12, and the third lens 13 are glass lenses and are all designed to be spherical, and the fourth lens 14 is an aspheric lens and is made of plastic. The surface type of each surface of the plastic aspheric surface is represented by an even-order aspheric surface. The represented rotation-symmetric polynomial aspheric surface is described by adding a polynomial increment on the basis of a spherical surface (or an aspheric surface determined by a quadric surface). The even-numbered aspheric surfaces are described by the even-numbered powers of the radial coordinate values, and the standard base is determined by the radius of curvature and the conic coefficients. The face coordinates are determined by:

wherein

As radial coordinate, α₁～α₈The high-order aspheric coefficients are k and c, 1/R and R, respectively.

In this embodiment, the surfaces of the lenses are numbered, and from the object side to the image side, the surfaces through which the light beams pass are 1, 2, and 3.

In this embodiment, specific parameters of each lens are as shown in table 4:

TABLE 4

In the data values in table 5, the signs of the curvature radii are represented by the image side as the origin, and the convex surface and the concave surface with respect to the image side are represented by positive and negative. Infinity stands for plane.

In addition, for aspheric surfaces, other aspheric coefficients are included as shown in table 5:

TABLE 5 aspherical surface coefficients

Number of noodles	4-degree aspheric coefficient a₂	6-th order aspheric coefficient a₃	Coefficient a of 8 th aspheric surface₄
				The 7 th plane	-0.013906411	0.0072633188	0.0096726842
The 8 th plane	-0.052492559	0.0081548436	0.0025596516

As shown in fig. 4-6, fig. 4 is a wave aberration rms diagram of a DMS wide-angle camera lens suitable for an OV9284 chip; FIG. 5 is a distortion diagram of a DMS wide-angle camera lens suitable for use with an OV9284 chip; fig. 6 is a MTF graph of a DMS wide-angle imaging lens suitable for the OV9284 chip.

In fig. 4, the vertical axis represents the root mean square wavefront error in wavelength; the horizontal axis is a visual field in mm in the Y direction, wherein the Y direction is a meridian plane; the reference point is the centroid. Wherein, the curve a is a root mean square wave front error curve with the wavelength of poly (complex color, i.e. the comprehensive meaning of three wavelengths); the curve b is a root-mean-square wavefront error curve with the wavelength of 0.935 mu m; the curve c is a root mean square wavefront error curve with the wavelength of 0.940 mu m; the d-curve is the root mean square wavefront error curve with a wavelength of 0.945 μm.

In fig. 5, the left image represents curvature of field, the horizontal axis represents the size of aberration, and the vertical axis represents the Y field of view; the right image represents distortion, with the horizontal axis representing distortion in percent and the vertical axis representing the Y field of view. The lower table in fig. 5 shows that the half field angle of the system is 40.378 °, i.e. 40.378 ° x 2 — 80.756 °.

In fig. 6, the different curves represent different fields of view; the vertical axis represents the amplitude versus function MTF and the horizontal axis represents the spatial frequency in pairs per millimeter.

By adding the thicknesses or air intervals in table 4, it can be seen that the lens length in this embodiment is only 12.9mm, and the length of the on-vehicle imaging lens is usually less than 20mm, so the length of the whole system of the DMS wide-angle imaging lens provided in this embodiment is short; according to the long-term practice and actual use requirement judgment standard of the photoelectric instrument industry, the imaging quality is considered to be excellent when the root mean square wave aberration is less than 1/4 wavelengths, namely less than 0.25 wavelength, and the use requirement is met, and as can be seen from the root mean square wave aberration diagram shown in FIG. 4, the root mean square wave aberration is less than 0.17 wavelength, the imaging quality is very good, and the use requirement is met; according to the long-term practice and practical use requirement judgment standard of the photoelectric instrument industry, the relative distortion of the camera lens with the visual angle close to or larger than 80 degrees is usually required to be less than 10%, and as can be seen from the distortion diagram shown in fig. 5, the maximum distortion of the embodiment does not exceed 3%, and the distortion is very small, so that the use requirement is met. Therefore, the DMS wide-angle imaging lens provided in this embodiment has small geometric aberration, and meets the use requirements; according to the long-term practice and practical use requirement judgment standard of the photoelectric instrument industry, for the camera lens with the field angle close to or larger than 80 degrees, the MTF values of the MTF values in the center and most fields are larger than 0.3 under the nyquist sampling frequency, the MTF value of the full field is larger than 0.15, the use requirement can be well met, as can be seen from the MTF graph in fig. 6, under the nyquist sampling frequency, as shown in fig. 6, when the frequency is 133, the MTF value is minimum, but the MTF value of the most fields of the system is larger than 0.3, and the MTF curve value of the individual fields close to the full field is also basically larger than 0.2, therefore, the wide-angle camera lens provided by the embodiment meets the use requirement.

Example two

Referring to fig. 7, fig. 7 is a schematic structural diagram of a DMS wide-angle imaging lens for an AR0135AT chip according to an embodiment of the present invention; the DMS wide-angle camera lens for the AR0135AT chip comprises a first lens 21, a second lens 22, a third lens 23 and a fourth lens 24 which are sequentially arranged from an object side to an image side, and after light is emitted by the system, the light is finally formed on an AR0135AT type photosensitive chip 27 through an optical filter 25 and a chip protection glass 26.

In this embodiment, the first lens 21, the second lens 22 and the third lens 23 are glass lenses and are all designed to be spherical, and the fourth lens 24 is an aspheric lens and is made of plastic. The surface type of each surface of the plastic aspheric surface is represented by an even-order aspheric surface. The represented rotation-symmetric polynomial aspheric surface is described by adding a polynomial increment on the basis of a spherical surface (or an aspheric surface determined by a quadric surface). The even-numbered aspheric surfaces are described by the even-numbered powers of the radial coordinate values, and the standard base is determined by the radius of curvature and the conic coefficients. The face coordinates are determined by:

wherein

In this embodiment, specific parameters of each lens are as shown in table 6:

TABLE 6

In the data values in table 7, the signs of the curvature radii are represented by the image side as the origin, and the convex surface and the concave surface with respect to the image side are represented by positive and negative. Infinity stands for plane.

In addition, for aspheric surfaces, other aspheric coefficients are included as shown in table 7:

TABLE 7 aspherical coefficients

Number of noodles	4-degree aspheric coefficient a₂	6-th order aspheric coefficient a₃	Coefficient a of 8 th aspheric surface₄
				The 7 th plane	-0.014789817	0.0069554641	-5.5103157e-05
The 8 th plane	-0.02141388	0.0034870092	0.00013305876

Please refer to fig. 8-10 after experimental verification or software simulation, wherein fig. 8 is a wave aberration rms diagram of a DMS wide-angle camera lens suitable for an AR0135AT chip; fig. 9 is a distortion diagram of a DMS wide-angle imaging lens suitable for an AR0135AT chip; fig. 10 is an MTF graph of a DMS wide-angle imaging lens suitable for an AR0135AT chip. The horizontal and vertical coordinates in the drawings represent meanings, please refer to the explanations of fig. 4-6, which are not described in detail in this embodiment.

By adding the thicknesses or air intervals in table 6, it can be seen that the length of the lens in this embodiment is only 14mm, and the length of the imaging lens mounted on the vehicle is usually less than 20mm, so the length of the whole system of the DMS wide-angle imaging lens provided in this embodiment is short; according to the long-term practice and actual use requirement judgment standard of the photoelectric instrument industry, the imaging quality is considered to be excellent when the root mean square wave aberration is less than 1/4 wavelengths, namely less than 0.25 wavelength, and the use requirement is met, and as can be seen from the root mean square wave aberration diagram shown in FIG. 8, the root mean square wave aberration is less than 0.17 wavelength, the imaging quality is very good, and the use requirement is met; according to the long-term practice and practical use requirement judgment standard of the photoelectric instrument industry, the relative distortion of the camera lens with the visual angle close to or larger than 80 degrees is usually required to be less than 10%, and as can be seen from the distortion diagram shown in fig. 9, the maximum distortion of the embodiment does not exceed 1%, and the distortion is very small, so that the use requirement is met. Therefore, the DMS wide-angle imaging lens provided in this embodiment has small geometric aberration, and meets the use requirements; according to the long-term practice and practical use requirement judgment standard of the photoelectric instrument industry, for an image pickup lens with a field angle close to or larger than 80 degrees, the MTF values of the MTF values in the center and most fields are larger than 0.3 under the Nyquist sampling frequency, the MTF value of the full field is larger than 0.15, the use requirement can be well met, as can be seen from the MTF graph in FIG. 10, under the Nyquist sampling frequency, the frequency is 133, the MTF value is minimum, but the MTF value of most fields of the system is larger than 0.3, and the MTF value of an individual field curve close to the full field is also basically larger than 0.2, so that the embodiment meets the use requirement.

In addition, as can be seen from the lower table in fig. 9, the half angle of view of the system is 39.632 °, that is, the full angle of view is 39.632 ° × 2 — 79.264 °.

As can be seen by comparing table 4 in the first embodiment with table 6 in the second embodiment, when the present invention is applied to several lenses of two DMS wide-angle imaging lenses, the radii of curvature of the first surface 1 of the first lens are both 4.4mm, and the radii of curvature of the second surface 2 are both 2.4 mm; the third surface 3 of the second lens has a radius of curvature of-3.9 mm and the fourth surface 4 has a radius of curvature of-4.1 mm. That is, the shapes of the first lens and the second lens are the same in the first embodiment and the second embodiment, and in both embodiments, only the air space between the first lens and the second lens is changed, and the shapes and the spaces of the third lens and the fourth lens are changed, so that the first lens and the second lens are shared in different systems.

In summary, the DMS wide-angle camera lens provided by the present invention has the following beneficial effects:

(1) in the DMS wide-angle camera lens, the front two glass lenses are shared, and 1 glass lens and 1 plastic aspheric lens are adopted, so that the DMS wide-angle camera lens can be simultaneously used for two CMOS photosensitive chips of AR0135AT and OV 9284. The two front lenses can be processed in a large amount at one time by adopting the same template die, and are simultaneously suitable for two different lenses of two different CMOS photosensitive chips, so that the processing procedure is greatly simplified, the processing cost is reduced, and errors caused by different types of materials are reduced.

(2) The DMS wide-angle camera lens has the field angle of 80 degrees, but only adopts 3 glass lenses and 1 plastic lens, so that the number of the lenses of the whole system is reduced, the structure is greatly simplified, the processing and debugging requirements are low, and the cost is reduced.

(3) The aspheric coefficients of the plastic aspheric lens in the DMS wide-angle camera lens are all only minus 8 th power of 10, so that the processing precision of the plastic aspheric surface is greatly reduced, and the processing and detection difficulty is greatly reduced.

(4) The field angle of the DMS wide-angle camera lens reaches 80 degrees, the matching requirement of the detector main ray angle CRA is considered, vignetting and energy reduction are avoided, and energy on an image surface is uniform.

In addition, based on the same inventive concept, the present invention also provides a DMS wide-angle imaging system including: the camera lens comprises a photosensitive chip and a camera lens positioned on the photosensitive side of the photosensitive chip; the camera lens is a DMS wide-angle camera lens as described in any of the embodiments above.

In the embodiment of the present invention, the photosensitive chip is not limited, and optionally, the photosensitive chip includes: a CMOS photosensitive chip with the model number OV9284 and a CMOS photosensitive chip with the model number AR0135 AT.

It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. The term "comprising" is used to specify the presence of stated elements, but not to preclude the presence or addition of one or more other like elements in a claim or a device.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A DMS wide-angle imaging lens, comprising:

2. The DMS wide-angle imaging lens according to claim 1, wherein the second lens group includes: the third lens and the fourth lens are sequentially arranged from the object space to the image space;

3. The DMS wide-angle imaging lens of claim 2, wherein the fourth lens has an aspherical surface type expression:

wherein

4. The DMS wide-angle imaging lens according to claim 2, wherein the first lens, the second lens, and the third lens are all glass lenses; the fourth lens is a plastic lens.

5. The DMS wide-angle imaging lens of claim 4, wherein the first lens and the second lens are made of H-LAK3 glass, the third lens is made of H-ZF52 glass, and the fourth lens is made of E48R.

6. The DMS wide-angle camera lens of claim 5, wherein the first surface has a radius of curvature of 4.4mm, the second surface has a radius of curvature of 2.4mm, the third surface has a radius of curvature of-3.9 mm, and the fourth surface has a radius of curvature of-4.1 mm.

7. The DMS wide-angle camera lens according to claim 6, wherein the fifth surface has a radius of curvature of 3.08 mm; the radius of curvature of the sixth surface is-24.24 mm.

8. The DMS wide-angle camera lens according to claim 6, wherein the fifth surface has a radius of curvature of 4.14 mm; the radius of curvature of the sixth surface is-13.90 mm.

9. A DMS wide-angle imaging system, comprising:

the camera lens is a DMS wide-angle camera lens according to any one of claims 1 to 8.

10. The DMS wide-angle imaging system according to claim 9, wherein the photosensitive chip includes: a CMOS photosensitive chip with the model number OV9284 and a CMOS photosensitive chip with the model number AR0135 AT.