Vehicle-mounted night vision DMS lens

Abstract

The utility model relates to the field of vehicle-mounted DMS lenses, in particular to a vehicle-mounted night vision DMS lens, which comprises a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4 which are sequentially arranged at intervals from left to right along a light incident light path, a diaphragm STO is arranged in front of the first lens L1; an optical filter IR is arranged on the rear side of the fourth lens L4; the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 are all glass spherical lenses. The beneficial effects of the utility model are that the number of used lenses is small, the overall reliability of the system is high, the assembling sensitivity is reduced, the enough field angle and the large clear aperture light incoming amount are ensured, and the edge imaging quality is good; meanwhile, the lens is of a full-glass structure, stable imaging can be achieved at the limiting temperature ranging from-40 DEG C to 105 DEG C, and aging, chemical corrosion resistance, mechanical vibration and the like completely meet the vehicle-specification-level reliability requirement.

Description

Technical Field

[0001] The utility model relates to the field of vehicle-mounted DMS lenses, in particular to a vehicle-mounted night vision DMS lens. Background Art

[0002] As cars become more and more popular, driving safety issues are becoming increasingly serious. In-vehicle DMS fatigue driving monitoring is one of the important monitoring methods. Currently, there are not many lenses that can be directly used for fatigue driving monitoring. DMS lenses require a specific field of view, high-definition image quality under low light conditions, good light absorption effect on light sources under strong light, and stable and clear imaging under different temperatures.

[0003] The existing field of view DMS lens still has the defects of small field of view angle, narrow visual range and the usable environment is limited by the reliability of the lens. Utility Model Content

[0004] The technical problem to be solved by the utility model is that the existing field of view DMS lens has a small field of view angle and a narrow visual range; and the usable environment is limited by the reliability of the lens.

[0005] In order to solve the above problems, the technical solution adopted by the utility model is: a vehicle-mounted night vision DMS lens, comprising a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4 which are arranged in sequence from left to right along the incident light path of the light; an aperture STO is arranged in front of the first lens L1; a filter IR is arranged on the rear side of the fourth lens L4; the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are all glass spherical lenses.

[0006] The beneficial effects of the utility model are: a small number of lenses are used, the overall reliability of the system is high, the assembly sensitivity is reduced while ensuring a sufficient field angle and a large amount of light entering the aperture, and the edge imaging quality is good; at the same time, the lens adopts a full-glass structure, which can stably form images under extreme temperatures of -40℃-105℃, and the aging, chemical corrosion resistance, mechanical vibration, etc. fully meet the automotive-grade reliability requirements.

[0007] As a further improvement of the present invention, the technical problem to be solved is: better imaging quality of the optical system requires optimization of the lens optical coefficient.

[0008] In order to solve the above technical problems, the utility model further improves the technical solution adopted as follows: the first lens L1 satisfies the relationship: Nd≥2.0, Vd≤25.4; the second lens L2 satisfies the relationship: Nd≥1.6, Vd≤38; the third lens L3 satisfies the relationship: Nd≥2.0, Vd≤25.4; the fourth lens L4 satisfies the relationship: Nd≥2.0, Vd≤25.4, wherein Nd is the refractive index and Vd is the Abbe constant.

[0009] The beneficial effects of the above improvements are: through the optical system composed of the above lenses, the total length of the optical path is short, the lens volume is small, the back focus is large, and it can be used with cameras with various different interfaces; at the same time, the system aperture is large and the imaging quality is excellent.

[0010] As a further improvement of the utility model, the technical problem to be solved is: the current on-site DMS lens generally has a pixel of about 1 million, the clarity is not enough, and the visual effect is poor.

[0011] In order to solve the above technical problems, the utility model further improves the technical solution adopted as follows: the first lens L1 is a positive meniscus lens, whose object side surface is convex and whose image side surface is flat; the second lens L2 is a double concave negative lens, whose object side surface is concave and whose image side surface is concave; the third lens L3 is a positive meniscus lens, whose object side surface is concave and whose image side surface is convex; the fourth lens L4 is a positive meniscus lens, whose object side surface is convex and whose image side surface is concave.

[0012] As a further improvement of the utility model, the technical problem to be solved is: the meniscus lens with the convex surface of the first lens facing outward can collect light with a large field of view as much as possible and allow it to enter the optical system; the second lens can further reduce the incident angle of light with a large field of view, which is conducive to controlling the chief ray angle CRA.

[0013] As a further improvement of the utility model, the technical problem to be solved is: the existing DMS lens has a wide filtering band, a low pass rate, and blurred imaging, and in order to obtain a better imaging quality of the overall optical system, the lens optical coefficient needs to be optimized.

[0014] In order to solve the above technical problems, the utility model further improves the technical solution adopted as follows: the focal length of the optical system is f, the focal lengths of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are f1, f2, f3, and f4 respectively, wherein f1, f2, f3, and f4 satisfy the following ratio with f: 1 <f1 / f<2,-0.5<f2 / f<-1,1<f3 / f<2,2<f4 / f<3。

[0015] The beneficial effect of the above improvement is: by reasonably distributing the focal length of the optical system formed by the utility model according to the above ratio, each lens is in a certain ratio relative to the focal length of the system, so that the aberration of the optical system formed by the utility model in the wavelength range of 920 to 960 nm can be reasonably corrected and balanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the internal structure of the lens of the imaging plane of the utility model.

[0017] Figure 2 It is the MTF curve diagram of the lens optical system in the utility model.

[0018] Figure 3 It is a through-focus MTF curve diagram of the lens optical system in the utility model.

[0019] Figure 4 This is a table showing the curvature radius R, thickness d, refractive index and Abbe number corresponding to each lens in the optical system of the utility model in Example 5.

[0020] The text labels in the figure indicate: L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; IR, filter; STO, aperture. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solution of the utility model, the utility model is described in detail below in conjunction with the accompanying drawings. The description in this part is only exemplary and explanatory and should not have any limiting effect on the protection scope of the utility model.

[0022] Embodiment 1:

[0023] A vehicle-mounted night vision DMS lens, comprising a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4, which are arranged in sequence from left to right along an incident light path of light; an aperture STO is arranged in front of the first lens L1; a filter IR is arranged on the rear side of the fourth lens L4; the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are all glass spherical lenses.

[0024] Embodiment 2:

[0025] As a further optimization of the above embodiment: a vehicle-mounted night vision DMS lens, including a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4, which are arranged in sequence from left to right along the incident light path of the light; an aperture STO is arranged in front of the first lens L1; a filter IR is arranged on the rear side of the fourth lens L4; the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are all glass spherical lenses. The first lens L1 satisfies the relationship: Nd≥2.0, Vd≤25.4; the second lens L2 satisfies the relationship: Nd≥1.6, Vd≤38; the third lens L3 satisfies the relationship: Nd≥2.0, Vd≤25.4; the fourth lens L4 satisfies the relationship: Nd≥2.0, Vd≤25.4, where Nd is the refractive index and Vd is the Abbe constant.

[0026] Embodiment 3:

[0027] As a further optimization of the above embodiment: a vehicle-mounted night vision DMS lens, including a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4, which are arranged in sequence from left to right along the incident light path of the light; an aperture STO is arranged in front of the first lens L1; a filter IR is arranged on the rear side of the fourth lens L4; the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are all glass spherical lenses. The first lens L1 is a positive meniscus lens, whose object side is convex and the image side is flat; the second lens L2 is a double concave negative lens, whose object side is concave and the image side is concave; the third lens L3 is a positive meniscus lens, whose object side is concave and the image side is convex; the fourth lens L4 is a positive meniscus lens, whose object side is convex and the image side is concave.

[0028] Embodiment 4:

[0029] As a further optimization of the above embodiment: a vehicle-mounted night vision DMS lens includes a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4 arranged in sequence from left to right along the incident light path of the light; an aperture STO is arranged in front of the first lens L1; a filter IR is arranged on the rear side of the fourth lens L4; the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are all glass spherical lenses. The focal length of the optical system is f, and the focal lengths of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are f1, f2, f3, and f4 respectively, where f1, f2, f3, and f4 satisfy the following ratio with f: 1 <f1 / f<2,-0.5<f2 / f<-1,1<f3 / f<2,2<f4 / f<3。

[0030] Embodiment 5:

[0031] As a further optimization of the above embodiment: Figure 4 As shown, the embodiment uses four lenses as an example, and through the reasonable allocation of the optical focal length, surface shape, center thickness of each lens and axial spacing between each lens, the field of view of the lens is effectively expanded, the total length of the lens is shortened, the distortion and illumination of the lens are guaranteed, and the resolution and imaging quality of the lens are improved.

[0032] In the embodiment, the technical indicators achieved by this optical system are as follows:

[0033] (1) Focal length: EFL = 5.04 mm; (2) Aperture F = 2.0; (3) Field of view: D ≥ 72.9°, H ≥ 55.2°, D ≥ 44.5°; (4) Optical distortion: -18.11%; (5) Imaging circle diameter greater than φ6.5; (6) Working band: 920-960 nm; (7) Total optical length TTL ≤ 10.82 mm; (8) This lens is suitable for 2 million pixel CCD or CMOS cameras.

[0034] The optical system composed of the above lenses has a long focal length, a large aperture, small distortion and excellent imaging quality;

[0035] Figure 2 and Figure 3 is the MTF curve and defocus MTF curve of the optical system. Figure 2 , Figure 3 It can be seen that the optical system has excellent imaging quality and fully meets the requirements of two million pixel photography.

[0036] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0037] This article uses specific examples to illustrate the principles and implementation methods of the utility model. The above examples are only used to help understand the method and core ideas of the utility model. The above is only the preferred implementation method of the utility model. It should be pointed out that due to the limitations of textual expression, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principle of the utility model, they can make several improvements, embellishments or changes, and can also combine the above technical features in an appropriate manner; these improvements, embellishments, changes or combinations, or the direct application of the concept and technical solution of the utility model to other occasions without improvement, should be regarded as the protection scope of the utility model.

Claims

1. A vehicle-mounted night vision DMS lens, characterized by: The invention comprises a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4 which are arranged in sequence from left to right along the incident light path of the light; a stop STO is arranged in front of the first lens L1; a filter IR is arranged at the rear side of the fourth lens L4; the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 are all glass spherical lenses; the first lens L1 satisfies the relationship: Nd≥2.0, Vd≤25.4; the second lens L2 satisfies the relationship: Nd≥1.6, Vd≤38; the third lens L 3 satisfies the relationship: Nd≥2.0, Vd≤25.4; the fourth lens L4 satisfies the relationship: Nd≥2.0, Vd≤25.4, wherein Nd is the refractive index and Vd is the Abbe constant; the first lens L1 is a positive meniscus lens, whose object side surface is convex and whose image side surface is flat; the second lens L2 is a double concave negative lens, whose object side surface is concave and whose image side surface is concave; the third lens L3 is a positive meniscus lens, whose object side surface is concave and whose image side surface is convex; the fourth lens L4 is a positive meniscus lens, whose object side surface is convex and whose image side surface is concave.

2. The vehicle-mounted night vision DMS lens according to claim 1, characterized in that: The focal length of the optical system formed by the lens is f, and the focal lengths of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are f1, f2, f3, and f4 respectively, wherein f1, f2, f3, and f4 satisfy the following ratio with f: 1 <f1 / f<2,-0.5<f2 / f<-1,1<f3 / f<2,2<f4 / f<3。

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