A 4K driving recorder lens

Abstract

The present invention discloses a 4K driving recorder lens, which specifically relates to the technical field of driving recorders, including a first lens, a second lens is provided on one side of the first lens, a third lens is provided on one side of the second lens, a fourth lens is provided on one side of the third lens, a fifth lens is provided on one side of the fourth lens, a sixth lens is provided on one side of the fifth lens, and a seventh lens is provided on one side of the sixth lens. The present invention adopts seven lenses, and four of the lenses are aspheric lenses made of plastic materials, which reduces weight and cost, improves competitiveness, and corrects aberrations by optimizing the positive and negative focal lengths of each lens. At the same time, it overcomes the defect that aspheric lenses made of plastic materials are prone to focus drift in high and low temperature environments due to their large expansion coefficients, so that the focus drift is controlled within a reasonable range, and has the characteristics of excellent resolution under high and low temperature conditions, thereby increasing the range of use occasions and environmental conditions, and improving quality and competitiveness.

Description

Technical Field

[0001] The present invention relates to the technical field of driving recorders, and more specifically, to a 4K driving recorder lens. Background Art

[0002] In the field of automobile assisted driving, driving recorders are commonly used equipment, and lenses are the main components of driving recorders. Lens performance directly affects the image quality and imaging field of view. At present, driving recorders mainly use chips of one-third inch or less, and the pixels are generally less than 5 million. With the continuous improvement of the technical indicators of recorders, large-target imaging elements are used to enhance the image quality. However, this requires that the imaging area of ​​the lens also needs to be able to adapt to the large-target imaging element. When the imaging area of ​​the lens increases, higher requirements are also put forward for the spherical aberration, coma, chief ray incidence angle (CRA), and chromatic aberration correction capabilities of the lens. At present, the existing lenses usually have a small aperture (generally the aperture (F / #) is about 2.0) under the conditions of large target surface and high resolution (supporting up to 8 million pixel cameras), and the small aperture will make the lens unable to clearly image in low light conditions. Based on this, it is necessary to develop a lens that can achieve a starlight-level large aperture under the conditions of large target surface and high resolution (supporting up to 8 million pixel cameras).

[0003] The patent application publication number CN 208721878 U discloses a 2K large aperture 500w driving recorder lens, including a lens housing and a first lens element, a second lens element, a third lens element, an aperture, a fourth lens element, a fifth lens element, a sixth lens element, a cover and a lens barrel arranged in sequence from the object side to the image side in the lens housing; 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 adopts 6 glass lenses, which can effectively correct the aberration in the optical system, achieve satisfactory optical characteristics and a wider total field of view and aperture, with an angle of 140°, and the relative brightness of the edge reaches 99%, the optical distortion is <25%, the total optical length is 17.25mm, the aperture is 1.8 and it can withstand high temperatures above 100 degrees, and can achieve the requirements of a lens at the 5 million pixel level, which can meet the special application requirements of the lens.

[0004] However, the above technical solution still has many disadvantages in actual application, such as small target surface, which can only match 1 / 2.7” chip at most, and cannot match chips with larger target surface such as 1 / 2” and 1 / 1.8” with better photosensitivity and imaging quality, and it only has 500 pixels, which is relatively low. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a 4K driving recorder lens. By adopting seven lenses, four of which are aspheric lenses made of plastic material, the weight and manufacturing cost of the lens are effectively reduced, and the product competitiveness is improved. By optimizing the positive and negative focal lengths of each lens, the lens aberration is effectively corrected. At the same time, the defect that the aspheric lens made of plastic material is prone to focus drift in high and low temperature environments due to its large expansion coefficient is overcome. By adopting this configuration, the focus drift of the lens of this product is controlled within a reasonable range, and it has the characteristics of excellent resolution under high and low temperature conditions, thereby increasing the use occasions and environmental conditions of the lens, and improving the quality and competitiveness of the lens product.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a 4K driving recorder lens, comprising a first lens, a second lens is provided on one side of the first lens, a third lens is provided on one side of the second lens, a fourth lens is provided on one side of the third lens, a fifth lens is provided on one side of the fourth lens, a sixth lens is provided on one side of the fifth lens, a seventh lens is provided on one side of the sixth lens, a filter is provided on one side of the seventh lens, and a photosensitive sheet is provided on one side of the filter;

[0007] 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.

[0008] In a preferred embodiment, the first lens, the second lens and the sixth lens all have negative focal lengths, and the third lens, the fourth lens, the fifth lens and the seventh lens all have positive focal lengths.

[0009] In a preferred embodiment, the first lens is a meniscus glass spherical lens.

[0010] In a preferred embodiment, the second lens is a meniscus-shaped plastic aspherical lens.

[0011] In a preferred embodiment, the third lens and the fourth lens are both biconvex glass spherical lenses.

[0012] In a preferred embodiment, the fifth lens is a biconvex plastic aspheric lens.

[0013] In a preferred embodiment, the sixth lens is a biconcave plastic aspheric lens.

[0014] In a preferred embodiment, the seventh lens is a biconvex plastic aspheric lens.

[0015] In a preferred embodiment, the surface of the first lens facing the object plane is convex, the surface of the first lens facing the image plane is concave, the surface of the second lens facing the object plane is concave, and the surface of the second lens facing the image plane is a near plane.

[0016] In a preferred embodiment, the refractive index of the sixth lens satisfies: nd6 is greater than 1.63.

[0017] Technical effects and advantages of the present invention:

[0018] The present invention provides a lens with a large target surface, 4K megapixel high resolution, large aperture, strong resistance to environmental temperature changes and low cost. Seven lenses are used, and four of the lenses are aspheric lenses made of plastic material, which effectively reduces the weight and manufacturing cost of the lens and improves the product competitiveness. By optimizing the positive and negative focal lengths of each lens, the lens aberration is effectively corrected, and at the same time overcomes the defect that the aspheric lens made of plastic material is prone to focus drift in high and low temperature environments due to its large expansion coefficient. By adopting this configuration, the focus drift of the lens of this product is controlled within a reasonable range, and the lens has the characteristics of excellent resolution under high and low temperature conditions, thereby increasing the use occasions and environmental conditions of the lens, and improving the quality and competitiveness of the lens product. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 This is a first analytical diagram of an embodiment of the present invention.

[0021] Figure 3 This is a second analytical diagram of an embodiment of the present invention.

[0022] Figure 4 This is a Spot map of an embodiment of the present invention.

[0023] Figure 5 2 is a field diagram of an embodiment of the present invention.

[0024] Figure 6 2 is a distortion diagram of an embodiment of the present invention.

[0025] Figure 7 This is an analytical diagram of an embodiment of the present invention at a low temperature of minus 40 degrees.

[0026] Figure 8 This is an analytical diagram of an embodiment of the present invention at a high temperature of 85 degrees.

[0027] The reference numerals are: 1 first lens, 2 first lens, 3 first lens, 4 first lens, 5 first lens, 6 first lens, 7 first lens, 8 filter, 9 photosensitive film. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1: According to Figure 1-8 A 4K driving recorder lens shown in the figure comprises a first lens 1, a second lens 2 is provided on one side of the first lens 1, a third lens 3 is provided on one side of the second lens 2, a fourth lens 4 is provided on one side of the third lens 3, a fifth lens 5 is provided on one side of the fourth lens 4, a sixth lens 6 is provided on one side of the fifth lens 5, a seventh lens 7 is provided on one side of the sixth lens 6, a filter 8 is provided on one side of the seventh lens 7, and a photosensitive film 9 is provided on one side of the filter 8;

[0030] 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.

[0031] 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.

[0032] The first lens 1 is a meniscus glass spherical lens.

[0033] The second lens 2 is a meniscus-shaped plastic aspherical lens.

[0034] The third lens 3 and the fourth lens 4 are both biconvex glass spherical lenses.

[0035] The fifth lens 5 is a biconvex plastic aspherical lens.

[0036] The sixth lens 6 is a biconcave plastic aspherical lens.

[0037] The seventh lens 7 is a biconvex plastic aspherical lens.

[0038] The surface of the first lens 1 facing the object plane is convex, the surface of the first lens 1 facing the image plane is concave, the surface of the second lens 2 facing the object plane is concave, and the surface of the second lens 2 facing the image plane is a near plane.

[0039] The refractive index of the sixth lens 6 satisfies: nd6 is greater than 1.63.

[0040] In an embodiment, when the working distance is infinite, the total focal length of the present invention is

[0041] f=3.87mm, FNO=1.60, field of view FOV=152°, total lens length TTL=22.5mm, can match 1 / 1.8” and below chips, maximum image plane diameter can reach 9.5mm, various parameters of the lens group are listed in Table 1:

[0042]

[0043]

[0044] Table 1

[0045] From Table 1, we can get:

[0046] f2*f6 / f5*f7=(-12.369651)*(-5.208549) / (5.535999*9.823782)=1.18, Nd6=1.661417, all meet the requirements. In addition, in this embodiment, the surfaces S3 and S4 of the second lens 2, the surfaces S9 and S10 of the fifth lens 5, the surfaces S11 and S12 of the sixth lens 6, and the surfaces S13 and S14 of the seventh lens 7 are aspherical surfaces, and the relevant values ​​of the aspherical surfaces are listed in Table 2 in sequence:

[0047]

[0048]

[0049] Table 2

[0050] In the above table of the embodiment of the present patent, Index is the refractive index, Radius is the radius of curvature, and the focal lengths of the first lens 1 to the seventh lens 7 are f1-f7 respectively. The lens provided in the embodiment is to provide a lens with a large target surface, 4K8 million pixel high resolution, large aperture, strong resistance to environmental temperature changes and low cost, so as to overcome the shortcomings in the prior art. Seven lenses are used, and four of them are aspheric lenses made of plastic material, which effectively reduce the weight and manufacturing cost of the lens and improve the product competitiveness. By optimizing the positive and negative focal lengths of each lens, the lens aberration is effectively corrected. At the same time, the defect of aspheric lenses made of plastic material, which are prone to focus drift in high and low temperature environments due to their large expansion coefficient, is overcome. By adopting this configuration, the focus drift of the lens of this product is controlled within a reasonable range, and it has the characteristics of excellent resolution under high and low temperature conditions, thereby increasing the use occasions and environmental conditions of the lens, and improving the quality and competitiveness of the lens product.

[0051] Embodiment 2:

[0052] The present invention Figure 2-Figure 8 The first analytical diagram, the second analytical diagram, the Spot diagram, the field curvature diagram, the distortion diagram, the analytical diagram at a low temperature of -40 degrees Celsius, and the analytical diagram at a high temperature of 85 degrees Celsius are shown in sequence. Figure 2 and Figure 3 As shown, Figure 2 Figure 3 2 is a graph of MTF (Modulation Transfer Function) values ​​at 20 degrees Celsius in the embodiment. The MTF value graph is based on the parameters in Table 1. The resolution and other qualities that are most important to an optical lens are measured. The MTF value is defined to be greater than 0 and less than 1. In the technical field, the closer the MTF value is to 1, the better the performance of the lens, that is, the higher the resolution. The variable is the spatial frequency, which is measured by the number of lines that can be presented within a range of mm. The unit is lp / mm. A fixed high-frequency (such as 200lp / mm) curve represents the resolution characteristic of the lens. The higher this curve is, the higher the resolution of the lens is. The ordinate is the MTF value, and the abscissa can be the distance from the center of the image field to the measuring point. The lens is a symmetrical structure centered on the optical axis. The imaging quality change law from the center to all directions is the same. Due to the influence of factors such as aberrations, the farther the distance between a point in the image field and the center of the image field is, the MTF value generally tends to decrease. Therefore, the distance from the center of the image field to the edge of the image field is used as the abscissa, which can reflect the imaging quality of the edge of the lens.

[0053] In addition, at a position deviated from the center of the image field, the MTF values ​​measured by the sinusoidal grating along the tangential direction and along the radial direction are different. The MTF curve generated by the lines parallel to the diameter is called the sagittal curve, marked as S (Sagittal), and the MTF curve generated by the lines parallel to the tangent is called the meridional curve, marked as T (Meridional). In this way, there are generally two MTF curves, namely the S curve and the T curve. Figure 2 and Figure 3 There are multiple groups of MTF curves from the center of the image field to the edge of the image field, reflecting that this lens system has a high resolution of up to 8 million pixels, and its optical performance is greatly improved compared with the current mainstream optical system.

[0054] Figure 4 This is the point diagram corresponding to the optical lens. Its centroid radius and geometric radius are shown in the figure, which can achieve good imaging quality.

[0055] The field curvature diagram corresponding to the visible light part of the lens system is composed of three curves T and three curves S, where the three curves T represent the aberrations of the tangential rays corresponding to the three wavelengths (486nm, 587nm and 656nm), and the three curves S represent the aberrations of the sagittal rays corresponding to the three wavelengths (486nm, 587nm and 656nm). The smaller the meridional field curvature value and the sagittal field curvature value, the better the imaging quality. Figure 5 As shown, the meridian field curvature value is controlled within the range of -0.02-0.02mm, and the sagittal field curvature value is controlled within the range of -0.02-0.02mm.

[0056] Since the refractive index of the lens material will change due to temperature, the lens size, lens barrel material, and lens mount material will expand and contract with temperature changes. These factors cause ordinary surveillance lenses to have different imaging back focal lengths (back intercepts) in high and low temperature environments, which is called temperature drift of lens imaging. Figure 7 and Figure 8 ,Depend on Figure 7 Figure 8 It can be seen that when the working temperature is between -40℃ and 85℃, the lens of this embodiment can still ensure that the image is as clear as at 20℃ (normal temperature) without refocusing. In summary, a 4K driving recorder lens of the present invention provides a lens with a large target surface, 4K8 million pixel high resolution, large aperture, strong resistance to environmental temperature changes and low cost. A total of seven lenses are used, and four of them are aspheric lenses made of plastic materials, which effectively reduce the weight and manufacturing cost of the lens and improve the product competitiveness. By optimizing the positive and negative focal lengths of each lens, the lens aberration is effectively corrected. At the same time, the defect of aspheric lenses made of plastic materials, which are prone to focus drift in high and low temperature environments due to their large expansion coefficients, is overcome. By adopting this configuration, the focus drift of the lens of this product is controlled within a reasonable range, and it has the characteristics of excellent resolution under high and low temperature conditions, thereby increasing the use occasions and environmental conditions of the lens and improving the quality and competitiveness of the lens product.

[0057] Finally, a few points should be explained: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, which may refer to mechanical connection or electrical connection, or internal communication between two components, or direct connection. "upper", "lower", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may change;

[0058] Secondly: In the drawings of the embodiments disclosed in the present invention, only the structures related to the embodiments disclosed in the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0059] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A 4K driving recorder lens, characterized in that: The lens comprises and only comprises the following lenses, which are seven in number, namely, a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5), a sixth lens (6) and a seventh lens (7); wherein the second lens (2) is disposed on one side of the first lens (1), the third lens (3) is disposed on one side of the second lens (2), the fourth lens (4) is disposed on one side of the third lens (3), the fifth lens (5) is disposed on one side of the fourth lens (4), the sixth lens (6) is disposed on one side of the fifth lens (5), the seventh lens (7) is disposed on one side of the sixth lens (6), a filter (8) is disposed on one side of the seventh lens (7), and a photosensitive sheet (9) is disposed 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 the following: 1.05<(f2*f6) / (f5*f7)<1.3; 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; The first lens (1) is a meniscus glass spherical lens; The second lens (2) is a meniscus-shaped plastic aspherical lens; The third lens (3) and the fourth lens (4) are both biconvex glass spherical lenses; The fifth lens (5) is a biconvex plastic aspherical lens; The sixth lens (6) is a biconcave plastic aspheric lens; The seventh lens (7) is a biconvex plastic aspheric lens; 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, and the surface of the second lens (2) facing the object plane is a concave surface.

2. The 4K driving recorder lens according to claim 1, characterized in that: The refractive index of the sixth lens (6) satisfies: nd6 is greater than 1.63.

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