CN110658610A

CN110658610A - 4K vehicle event data recorder camera lens

Info

Publication number: CN110658610A
Application number: CN201910937945.9A
Authority: CN
Inventors: 吴强华; 胡长涛; 张福美
Original assignee: Jiangxi Terrace Optics Co Ltd
Current assignee: Jiangxi Terrace Optics Co Ltd
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2020-01-07

Abstract

The invention discloses a 4K automobile data recorder lens, and particularly relates to the technical field of automobile data recorders. The invention adopts seven lenses, four of which are plastic aspheric lenses, thereby reducing the weight and the cost, improving the competitiveness, correcting the aberration by optimizing and configuring the positive and negative focal lengths of each lens, overcoming the defect that the plastic aspheric lens is easy to cause focus drift in high and low temperature environments due to large expansion coefficient, controlling the focus drift in a reasonable range, and having the characteristic of excellent analysis in high and low temperature conditions, thereby increasing the range of use occasions and environmental conditions and improving the quality and the competitiveness.

Description

4K vehicle event data recorder camera lens

Technical Field

The invention relates to the technical field of automobile data recorders, in particular to a 4K automobile data recorder lens.

Background

In the field of automobile driving assistance, a vehicle event data recorder is a common device, a lens is a main constituent part of the vehicle event data recorder, the performance of the lens directly affects the imaging quality and the imaging view field, at present, the vehicle event data recorder mainly uses a chip of one-third inch or less, pixels are generally less than 500 ten thousand, as the technical index requirement of the recorder is continuously improved, an imaging element with a large target surface is used for enhancing the imaging quality, but the imaging area of the lens needs to be adapted to the imaging element with the large target surface, and when the imaging area of the lens is increased, higher requirements are provided for spherical aberration, coma, a principal ray exit angle (CRA) and chromatic aberration correction capability of the lens. At present, under the condition that the existing lens meets the conditions of large target surface and high resolution (the maximum supports 800 ten thousand pixel cameras), the aperture is usually small (the aperture (F/#) is about 2.0 generally), and the lens cannot be clearly imaged under the condition of weak light due to the small aperture. Therefore, it is necessary to develop a lens capable of realizing a starlight level large aperture under the conditions of meeting the requirements of a large target surface and high resolution (the maximum support is 800 ten thousand pixel cameras).

Patent application publication No. CN 208721878U discloses a 2K large aperture 500w lens for a vehicle event data recorder, which includes a lens housing, and a first lens element, a second lens element, a third lens element, a diaphragm, a fourth lens element, a fifth lens element, a sixth lens element, a cover and a lens barrel arranged in the lens housing in sequence from an object side to an image side; 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 all glass lens elements. The utility model discloses a 6 glass lenses can effectively rectify the aberration among the optical system, reach the total angle of vision and the light ring of satisfied optical characteristic and broad, diagonal angle 140, edge relative brightness reaches 99% simultaneously, optical distortion < 25%, the total length of optics is 17.25mm, light ring 1.8 and resistant high temperature more than 100 degrees, can realize the camera lens requirement of 500 ten thousand pixel ranks, can satisfy the special application requirement of camera lens.

However, in practical application, the above technical solutions still have many disadvantages, such as that the target surface is small, the chip is maximally matched with 1/2.7 ", the chip with the larger target surface, such as 1/2" and 1/1.8 ", and the like, has better photosensitive effect and imaging quality, and only has 500 pixels, and the pixels are relatively low.

Disclosure of Invention

In order to overcome the above defects in the prior art, embodiments of the present invention provide a 4K vehicle event data recorder lens, which effectively reduces the lens weight and the manufacturing cost by using seven lenses, wherein four lenses are aspheric lenses made of plastic materials, thereby improving the product competitiveness, effectively correcting the lens aberration by optimizing and configuring the positive and negative focal lengths of each lens, and overcoming the defect that the aspheric lens made of plastic materials is likely to cause focus drift in high and low temperature environments due to a large expansion coefficient.

In order to achieve the purpose, the invention provides the following technical scheme: A4K automobile data recorder lens comprises a first lens, wherein a second lens is arranged on one side of the first lens, a third lens is arranged on one side of the second lens, a fourth lens is arranged on one side of the third lens, a fifth lens is arranged on one side of the fourth lens, a sixth lens is arranged on one side of the fifth lens, a seventh lens is arranged on one side of the sixth lens, a filter is arranged on one side of the seventh lens, and a photosensitive piece is arranged on one side of the filter;

the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are f1, f2, f3, f4, f5, f6 and f7 respectively, and satisfy: 1.05 < (f2 f6)/(f5 f7) < 1.3.

In a preferred embodiment, the first, second and sixth lenses each have a negative focal length, and the third, fourth, fifth and seventh lenses each have a positive focal length.

In a preferred embodiment, the first lens is a meniscus glass spherical lens.

In a preferred embodiment, the second lens is a meniscus plastic aspherical lens.

In a preferred embodiment, the third lens and the fourth lens are each a biconvex glass sphere lens.

In a preferred embodiment, the fifth lens is a biconvex plastic aspheric lens.

In a preferred embodiment, the sixth lens is a biconcave plastic aspheric lens.

In a preferred embodiment, the seventh lens is a biconvex plastic aspheric lens.

In a preferred embodiment, the surface of the first lens facing the object plane is a convex surface, the surface of the first lens facing the image plane is a concave surface, the surface of the second lens facing the object plane is a concave surface, and the surface of the second lens facing the image plane is a near-plane surface.

In a preferred embodiment, the refractive index of the sixth lens satisfies: nd6 is greater than 1.63.

The invention has the technical effects and advantages that:

the invention aims to provide a lens with a large target surface, 4K ten thousand pixels of high resolution, a large aperture, strong environmental temperature change resistance and low cost, which adopts seven lenses, wherein four lenses are aspheric lenses made of plastic materials, thereby effectively reducing the weight and the manufacturing cost of the lens, improving the product competitiveness, effectively correcting the aberration of the lens by optimally configuring the positive focal length and the negative focal length of each lens, overcoming the defect that the aspheric lens made of plastic materials is easy to cause focus drift under high and low temperature environments due to large expansion coefficient.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

Fig. 2 is a first analysis diagram according to the embodiment of the invention.

Fig. 3 is a second analysis diagram according to the embodiment of the invention.

Fig. 4 is a Spot diagram of an embodiment of the present invention.

Fig. 5 is a field diagram of an embodiment of the present invention.

FIG. 6 is a distortion diagram of an embodiment of the present invention.

FIG. 7 is an analysis diagram of the temperature of-40 ℃ according to the embodiment of the present invention.

FIG. 8 is an analytic view of the embodiment of the present invention at a temperature of above-zero 85 ℃.

The reference signs are: the lens comprises a first lens 1, a first lens 2, a first lens 3, a first lens 4, a first lens 5, a first lens 6, a first lens 7, a filter 8 and a light-sensitive sheet 9.

Detailed Description

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.

Example 1: the 4K automobile data recorder lens shown in the figures 1-8 comprises a first lens 1, wherein a second lens 2 is arranged on one side of the first lens 1, a third lens 3 is arranged on one side of the second lens 2, a fourth lens 4 is arranged on one side of the third lens 3, a fifth lens 5 is arranged on one side of the fourth lens 4, a sixth lens 6 is arranged on one side of the fifth lens 5, a seventh lens 7 is arranged on one side of the sixth lens 6, a filter 8 is arranged on one side of the seventh lens 7, and a photosensitive plate 9 is arranged on one side of the filter 8;

the focal lengths of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6 and the seventh lens 7 are f1, f2, f3, f4, f5, f6 and f7 respectively, and satisfy: 1.05 < f2 f6/f5 f7 < 1.3.

The first lens 1, the second lens 2, and the sixth lens 6 each have a negative focal length, and the third lens 3, the fourth lens 4, the fifth lens 5, and the seventh lens 7 each have a positive focal length.

The first lens 1 is a meniscus glass spherical lens.

The second lens 2 is a meniscus plastic aspheric lens.

The third lens 3 and the fourth lens 4 are both biconvex glass spherical lenses.

The fifth lens 5 is a biconvex plastic aspheric lens.

The sixth lens element 6 is a biconcave plastic aspheric lens element.

The seventh lens element 7 is a biconvex plastic aspheric lens element.

The surface of the first lens 1 facing the object plane is a convex surface, the surface of the first lens 1 facing the image plane is a concave surface, the surface of the second lens 2 facing the object plane is a concave surface, and the surface of the second lens 2 facing the image plane is a near plane.

The refractive index of the sixth lens 6 satisfies: nd6 is greater than 1.63.

In the embodiment, when the working distance is infinity, the total focal length f of the present invention is 3.87mm, FNO is 1.60, the field angle FOV is 152 °, the total lens length TTL is 22.5mm, 1/1.8 ″ and the following chips can be matched, the maximum image plane can reach 9.5mm, and the parameters of the lens group are listed in table 1 in sequence:

SUR	Radius	Thickness	Index	ABB	EFL-E
						1	20.737639	0.6	1.789128	61.247611	-6.720777
2	3.297148	3.314791
						3	-7.022484	3	1.54	55.785	-12.369651
4	140.266419	0.358565
						5	15.901749	0.835688	1.603658	31.315013	13.280063
6	-48.834627	0.1
						7	16.6952	2.32774	1.72916	54.673513	15.490148
8	-33.202334	0.1
						9	6.197352	2.434231	1.54	55.785	5.535999
10	-4.926716	0.1
						11	-9.274539	0.65	1.661417	20.412155	-5.208549
12	5.71319	0.852893
						13	6.207836	2.874921	1.54	55.785	9.823782
14	-29.377674	0.199667

TABLE 1

From table 1, it can be seen:

f2 f6/f5 f 7- (-12.369651) (-5.208549)/(5.535999 9.823782) ═ 1.18, Nd6 ═ 1.661417, and in this example, surfaces S3 and S4 of second lens 2, surfaces S9 and S10 of fifth lens 5, surfaces S11 and S12 of sixth lens 6, and surfaces S13 and S14 of seventh lens group 7 are aspherical surfaces, and their aspherical correlation values are listed in order in table 2:

TABLE 2

In the above table of the embodiment of the present invention, Index is a refractive Index, Radius is a curvature Radius, and the focal length of the first lens 1 to the seventh lens 7 is f1 to f7, the lens provided by the embodiment is characterized in that a large target surface, 4K800 ten thousand pixels of high resolution, a large aperture, strong environmental temperature change resistance and low cost are provided to overcome the disadvantages in the prior art, seven lenses are used, and four lenses are aspheric lenses made of plastic materials, thereby effectively reducing the weight and manufacturing cost of the lens, improving the competitiveness of the product, effectively correcting the aberration of the lens by optimizing and configuring the positive and negative focal lengths of the lenses, and simultaneously overcoming the defect that the aspheric lenses made of plastic materials are easy to cause focus drift in high and low temperature environments due to large expansion coefficients of the aspheric lenses, and by adopting the configuration, the focus drift of the lens of the product is controlled within a reasonable range, and the lens has the characteristic of excellent analysis under the conditions of high temperature and low temperature, thereby increasing the application occasions and the environmental condition range of the lens and improving the quality and the competitiveness of lens products.

Example 2:

fig. 2-8 of the present invention are a first analytical graph, a second analytical graph, a Spot graph, a field curvature graph, a distortion graph, an analytical graph at a low temperature of-40 degrees and an analytical graph at a high temperature of-85 degrees when a working distance is infinity, as shown in fig. 2 and fig. 3, wherein fig. 2 and fig. 3 are graphs of MTF (Modulation Transfer Function) values at 20 degrees celsius of an embodiment, the MTF value graph is based on the parameters in table 1, the most significant resolution of an optical lens is measured, the MTF definition MTF value is certainly greater than 0 and less than 1, the closer the MTF value is to 1 in the technical field, the more excellent the performance of the lens is, i.e. the resolution is high, the variable is a spatial frequency, the spatial frequency is measured by how many lines can be presented in a mm range, the unit thereof is expressed by lp/mm, and a fixed high frequency (e.g. 200lp/mm) curve represents the resolution characteristic of the lens, the higher the curve is, the higher the resolution of the lens is, the ordinate is the MTF value, the abscissa can set the distance from the center of the image field to the measurement point, the lens is of a symmetrical structure with the optical axis as the center, the change rule of the image quality from the center to each direction is the same, and due to the influence of factors such as aberration, the farther the distance from a certain point in the image field to the center of the image field is, the MTF value generally tends to decrease, so the distance from the center of the image field to the edge of the image field is taken as the abscissa, and the image quality at the edge of the lens can be reflected.

In addition, at a position deviated from the center of the image field, MTF values measured by the sinusoidal gratings of the line along the tangential direction and the line along the radial direction are different, the MTF curve generated by the line parallel to the diameter is called a sagittal curve, denoted as S (sagittal), and the MTF curve generated by the line parallel to the tangential direction is called a meridional curve, denoted as T (meridian), so that there are generally two MTF curves, i.e., the S curve and the T curve, and in fig. 2 and 3, there are multiple groups of MTF variation curves from the center of the image field to the edge of the image field, which reflects that the lens system has a higher resolving power, which can reach 800 ten thousand pixels, and the optical performance is greatly improved compared with the current mainstream optical system.

Fig. 4 is a dot array diagram corresponding to the optical lens, and the centroid radius and the geometric radius of the dot array diagram are shown, so that good imaging quality can be achieved.

The field curvature diagram corresponding to the visible light part of the lens system is composed of three curves T and three curves S, wherein the three curves T respectively represent the aberration of the meridional beams (Tangential Rays) corresponding to three wavelengths (486nm, 587nm and 656nm), the three curves S respectively represent the aberration of the sagittal beams (Sagitdial Rays) corresponding to three wavelengths (486nm, 587nm and 656nm), the smaller the meridional field curvature value and the sagittal field curvature value are, the better the imaging quality is, as shown in FIG. 5, the meridional field curvature value is controlled within the range of-0.02-0.02 mm, and the sagittal field curvature value is controlled within the range of-0.02-0.02 mm.

Because the refractive index of the lens material can be influenced by temperature and changed, the size of the lens, the material of the lens barrel and the material of the lens base can expand with heat and contract with cold along with the change of the temperature, and the factors cause that different imaging back focuses (back focal length) of the common monitoring lens can appear under the high and low temperature environment, which is called as the temperature drift of lens imaging.

Referring to fig. 7 and 8, as seen from fig. 7 and 8, the working temperature is-40 ℃ to 85 ℃, and the lens of the embodiment can still ensure that the imaging is still as clear as 20 ℃ (normal temperature) under the condition of not carrying out refocusing.

In summary, the 4K automobile data recorder lens of the invention provides a lens with a large target surface, 4K800 ten thousand pixels high resolution, large aperture, strong environmental temperature change resistance and low cost, which adopts seven lenses in total, and the four lenses are aspheric lenses made of plastic materials, thereby effectively reducing the weight and the manufacturing cost of the lens, improving the competitiveness of the product, the positive and negative focal lengths of each lens are optimized, so that the aberration of the lens is effectively corrected, and the problem that the plastic aspheric lens has large expansion coefficient is solved, the configuration is adopted to control the focus drift of the lens of the product within a reasonable range and has the characteristic of excellent analysis under high and low temperature conditions, therefore, the application occasions and the environmental condition range of the lens are increased, and the quality and the competitiveness of the lens product are improved.

The points to be finally explained are: first, in the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounted," "connected," and "connected" should be understood broadly, and may be a mechanical connection or an electrical connection, or a communication between two elements, and may be a direct connection, and "upper," "lower," "left," and "right" are only used to indicate a relative positional relationship, and when the absolute position of the object to be described is changed, the relative positional relationship may be changed;

secondly, the method comprises the following steps: in the drawings of the disclosed embodiments of the invention, only the structures related to the disclosed embodiments are referred to, other structures can refer to common designs, and the same embodiment and different embodiments of the invention can be combined with each other without conflict;

and finally: 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 invention, and any modifications, equivalents, improvements and the like that are within the spirit and principle of the present invention are intended to be included in the scope of the present invention.

Claims

1. A4K vehicle event data recorder camera lens includes first lens (1), its characterized in that: a second lens (2) is arranged on one side of the first lens (1), a third lens (3) is arranged on one side of the second lens (2), a fourth lens (4) is arranged on one side of the third lens (3), a fifth lens (5) is arranged on one side of the fourth lens (4), a sixth lens (6) is arranged on one side of the fifth lens (5), a seventh lens (7) is arranged on one side of the sixth lens (6), a filter (8) is arranged on one side of the seventh lens (7), and a photosensitive sheet (9) is arranged on one side of the filter (8);

the focal lengths of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5), the sixth lens (6) and the seventh lens (7) are respectively f1, f2, f3, f4, f5, f6 and f7, and the following conditions are satisfied: 1.05 < (f2 f6)/(f5 f7) < 1.3.

2. The 4K vehicle event data recorder lens of claim 1, characterized in that: the first lens (1), the second lens (2) and the sixth lens (6) all have negative focal lengths, and the third lens (3), the fourth lens (4), the fifth lens (5) and the seventh lens (7) all have positive focal lengths.

3. The 4K vehicle event data recorder lens of claim 1, characterized in that: the first lens (1) is a meniscus glass spherical lens.

4. The 4K vehicle event data recorder lens of claim 1, characterized in that: the second lens (2) is a meniscus plastic aspheric lens.

5. The 4K vehicle event data recorder lens of claim 1, characterized in that: the third lens (3) and the fourth lens (4) are biconvex glass spherical lenses.

6. The 4K vehicle event data recorder lens of claim 1, characterized in that: the fifth lens (5) is a biconvex plastic aspheric lens.

7. The 4K vehicle event data recorder lens of claim 1, characterized in that: the sixth lens (6) is a biconcave plastic aspheric lens.

8. The 4K vehicle event data recorder lens of claim 1, characterized in that: the seventh lens (7) is a biconvex plastic aspheric lens.

9. The 4K vehicle event data recorder lens of claim 1, characterized in that: the surface of the first lens (1) facing the object plane is a convex surface, the surface of the first lens (1) facing the image plane is a concave surface, the surface of the second lens (2) facing the object plane is a concave surface, and the surface of the second lens (2) facing the image plane is a near plane.

10. The 4K vehicle event data recorder lens of claim 1, characterized in that: the refractive index of the sixth lens (6) satisfies: nd6 is greater than 1.63.