3g3p wide-angle lens

Abstract

The application discloses a 3G3P wide-angle lens, which is sequentially provided with a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens and a sixth lens from an object side to an image side; the first lens, the third lens and the sixth lens are glass lenses, and the second lens, the fourth lens and the fifth lens are plastic lenses; the fourth lens and the fifth lens are glued to form a combined lens, and satisfy the conditions of -2.13 < f2 / f5 < -1.65 and -2.25 < f4 / f5 < -1.75, wherein f2 is the focal length of the second lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens. The glass-plastic combination of the lenses and the reasonable setting of the focal lengths of the lenses make the shift of the focal length of the lens in the temperature range of -55 DEG C to 90 DEG C controlled within ±0.01, and clear imaging in a wide temperature range is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical technology, in particular to a 3G3P wide-angle lens. BACKGROUND

[0002] In recent years, with the continuous development of vehicle-mounted video, people are more and more convenient when reversing, but people prefer that the vehicle-mounted camera has a wider view angle, and the camera volume is required to be smaller and smaller, that is, the number of lenses inside the lens should not be too much. At the same time, the lens is required to have good tolerance to environmental changes, especially to temperature changes, because the camera itself needs to dissipate heat when working, and some cameras are equipped with laser lights, and the laser light needs to release a large amount of heat when working, which causes the temperature of the lens to rise rapidly and the imaging quality to be affected. Therefore, how to develop a wide-angle lens that can still maintain good imaging quality in a wide temperature range has become a problem to be solved at present. SUMMARY

[0003] The purpose of the present application is to provide a 3G3P wide-angle lens with simple structure and less image quality damage in a wide temperature range.

[0004] To solve the above technical problems, the present application provides a 3G3P wide-angle lens, which is provided with a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens and a sixth lens from the object side to the image side in sequence, the first lens has a negative focal length with the convex surface facing the object side; the second lens has a negative focal length with the convex surface facing the object side; the third lens is a double-convex lens with a positive focal length; the fourth lens has a negative focal length with the convex surface facing the object side; the fifth lens is a double-convex lens with a positive focal length; the sixth lens has a positive focal length with the convex surface facing the object side.

[0005] The first lens, the third lens and the sixth lens are glass lenses, and the second lens, the fourth lens and the fifth lens are plastic lenses; the fourth lens and the fifth lens are glued to form a combined lens, and satisfy-2.13

[0006] Preferably, the change rate of the refractive index ND4 of the fourth lens with temperature T satisfies-0.67≥dND4 / dT≥-1.37.

[0007] Preferably, the change rate of the refractive index ND5 of the fifth lens with temperature T satisfies-0.77≥dND5 / dT≥-1.34.

[0008] Preferably, the first lens, the third lens and the sixth lens are glass spherical lenses, and the second lens, the fourth lens and the fifth lens are plastic aspherical lenses.

[0009] Preferably, the wide-angle lens satisfies 4.5 < TTL / EFL < 5.5, TTL is the distance between the point closest to the object side of the first lens and the imaging surface, and EFL is the focal length of the lens.

[0010] Preferably, the refractive index ND1 of the first lens is greater than 1.6.

[0011] Preferably, the refractive index ND3 of the third lens is greater than 1.8.

[0012] Preferably, the Abbe number VD3 of the third lens is less than 30.

[0013] Preferably, the Abbe number VD5 of the fifth lens is less than 35.

[0014] Preferably, the focal length f1 of the first lens and the focal length f of the wide-angle lens satisfy -11 < f1 / f < -5.

[0015] The present application has the following beneficial effects:

[0016] The wide-angle lens provided by the present application adopts glass lenses for the first lens, the third lens and the sixth lens, and plastic lenses for the second lens, the fourth lens and the fifth lens. By using the combination of glass and plastic lenses and by reasonably setting the focal lengths of the lenses, the shift of the focal length of the lens within the temperature range of -55℃ to 90℃ is controlled within ±0.01, and clear imaging within a wide temperature range is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of the 3G3P wide-angle lens in the present application;

[0018] Figure 2 is the defocus curve of the central field of view of 60 lp / mm of the wide-angle lens provided by the embodiment 1 of the present application at -55℃;

[0019] Figure 3 is the defocus curve of the central field of view of 60 lp / mm of the wide-angle lens provided by the embodiment 1 of the present application at 25℃;

[0020] Figure 4 is the defocus curve of the central field of view of 60 lp / mm of the wide-angle lens provided by the embodiment 1 of the present application at 90℃;

[0021] Figure 5 is the defocus curve of the central field of view of 60 lp / mm of the wide-angle lens provided by the comparative example 1 of the present application at -55℃;

[0022] Figure 6 is the defocus curve of the wide-angle lens provided by the present application comparative example 1 at 60 lp / mm of central field of view at 25℃;

[0023] Figure 7 is the defocus curve of the wide-angle lens provided by the present application comparative example 1 at 60 lp / mm of central field of view at 90℃;

[0024] Figure 8 is the defocus curve of the wide-angle lens provided by the present application comparative example 2 at 60 lp / mm of central field of view at -55℃;

[0025] Figure 9 is the defocus curve of the wide-angle lens provided by the present application comparative example 2 at 60 lp / mm of central field of view at 25℃;

[0026] Figure 10 is the defocus curve of the wide-angle lens provided by the present application comparative example 2 at 60 lp / mm of central field of view at 90℃. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0028] Please refer to Figure 1 The 3G3P wide-angle lens provided by the embodiments of the present application is sequentially provided with a first lens L1, a second lens L2, a third lens L3, a diaphragm ST, a fourth lens L4, a fifth lens L5 and a sixth lens L6 from the object side to the image side. The convex surface of the first lens L1 faces the object side and has a negative focal power. The convex surface of the second lens L2 faces the object side and has a negative focal power. The third lens L3 is a double convex lens and has a positive focal power. The convex surface of the fourth lens L4 faces the object side and has a negative focal power. The fifth lens L5 is a double convex lens and has a positive focal power. The convex surface of the sixth lens L6 faces the object side and has a positive focal power.

[0029] The first lens L1, the third lens L3 and the sixth lens L6 are glass lenses, and the second lens L2, the fourth lens L4 and the fifth lens L5 are plastic lenses. The fourth lens L4 and the fifth lens L5 are glued to form a combined lens, and satisfy -2.13 < f2 / f5 < -1.65 and -2.25 < f4 / f5 < -1.75, wherein f2 is the focal length of the second lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens.

[0030] As a preferred embodiment, the rate of change of the refractive index ND4 of the fourth lens L4 with respect to temperature T satisfies -0.67≥dND4 / dT≥-1.37 (10 -6 / °C), and the rate of change of the refractive index ND5 of the fifth lens L5 with respect to temperature T satisfies -0.77≥dND5 / dT≥-1.34 (10 -6 / °C). By reasonably controlling the rate of change of the refractive index of the fourth lens L4 and the fifth lens L5 with respect to temperature, the offset caused by thermal expansion and contraction of the mechanical structure in the wide-angle lens can be compensated, and the imaging quality in a wider temperature range can be further improved.

[0031] Further, the first lens L1, the third lens L3, and the sixth lens L6 are glass spherical lenses, and the second lens L2, the fourth lens L4, and the fifth lens L5 are plastic aspherical lenses. By reasonably using aspherical lenses in the lenses, not only the spherical aberration and the field curvature of the lens can be effectively reduced, but also the optical aberration can be better corrected, and the imaging clarity in the temperature range of -55°C to 90°C can be improved.

[0032] Further preferably, the refractive index ND1 of the first lens L1 is greater than 1.6. The refractive index ND3 of the third lens L3 is greater than 1.8, and the Abbe number VD3 is less than 30. The Abbe number VD5 of the fifth lens L5 is less than 35. By using a first lens with a high refractive index, a third lens with a high refractive index and a high dispersion, and a fifth lens with a high dispersion, the color aberration of the wide-angle lens can be effectively improved while ensuring the miniaturization of the lens.

[0033] Specifically, the wide-angle lens also satisfies 4.5<TTL / EFL<5.5, TTL is the distance between the point closest to the object side of the first lens and the imaging image plane, and EFL is the focal length of the lens. When the above condition is satisfied, it is helpful to shorten the total length of the wide-angle lens, and make the lens more lightweight.

[0034] The effects of the aforementioned 3G3P wide-angle lens are characterized and analyzed by specific examples and comparative examples.

[0035] Example 1

[0036] A 3G3P wide-angle lens, sequentially arranged from an object side to an image side are a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5 and a sixth lens L6, and the specific parameters of each lens are shown in Table 1. Among them, the first lens L1, the third lens L3 and the sixth lens L6 are glass lenses, and the second lens L2, the fourth lens L4 and the fifth lens L5 are plastic lenses; the fourth lens L4 and the fifth lens L5 are cemented to form a cemented surface S8, and satisfy f2 / f5=-1.72, f4 / f5=-1.93, wherein f2 is the focal length of the second lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, TTL / EFL=5.2, dND4 / dT=-0.97x10 -6 / ℃, dND5 / dT=-1.06x10 -6 / ℃.

[0037] Table 1

[0038]

[0039] Comparative Example 1

[0040] Based on the arrangement of the six lenses in Example 1, the fourth lens L4 and the fifth lens L5 are maintained in a cemented state, and only the material of the lens is adjusted, wherein the third lens L3 is a plastic lens.

[0041] Comparative Example 2

[0042] Based on the lens arrangement of three glass lenses and three plastic aspherical lenses in Example 1, the fourth lens L4 and the fifth lens L5 are maintained in a cemented state, and only the focal length of the lens is adjusted, wherein f2 / f5=-2.3, f4 / f5=-1.6.

[0043] Figures 2-10 The optical performance curves of the wide-angle lenses of Example 1 and Comparative Examples 1-2 are shown respectively. As can be seen from the figure, the wide-angle lens prepared in the example of the present application can correct aberration to a better level, and the shift of the refractive power of the lens is controlled within ±0.01 in the temperature range of-55℃-90℃, realizing clear imaging in a wider temperature range.

[0044] It should be noted that each of the above examples belongs to the same inventive concept, and the description of each example has its own emphasis. If not fully described in an individual example, reference can be made to the description in other examples.

[0045] The above embodiments only express the implementation of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application patent should be subject to the appended claims.

Claims

1. A 3G3P wide-angle lens, comprising, from the object side to the image side, a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, and a sixth lens, characterized in that, The convex surface of the first lens faces the object side and has a negative optical power; the convex surface of the second lens faces the object side and has a negative optical power; the third lens is a biconvex lens and has a positive optical power; the convex surface of the fourth lens faces the object side and has a negative optical power; The fifth lens is a biconvex lens and has a positive optical power; the convex surface of the sixth lens faces the object side and has a positive optical power; The first lens, the third lens, and the sixth lens are glass spherical lenses, and the second lens, the fourth lens, and the fifth lens are plastic aspherical lenses; the fourth lens and the fifth lens are glued to form a combined lens, and -1.72 < f2 / f5 < -1.65, -2.25 < f4 / f5 < -1.75 are satisfied, where f2 is the focal length of the second lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens; The rate of change of the refractive index ND4 of the fourth lens with respect to the temperature T satisfies -0.67 ≥ dND4 / dT ≥ -1.37; The rate of change of the refractive index ND5 of the fifth lens with respect to the temperature T satisfies -0.77 ≥ dND5 / dT ≥ -1.

34.

2. The 3G3P wide-angle lens according to claim 1, characterized in that, The wide-angle lens satisfies 4.5 < TTL / EFL < 5.5, where TTL is the distance from the point on the first lens closest to the object side to the imaging image plane, and EFL is the focal length of the lens.

3. A 3G3P wide-angle lens according to claim 1, characterized in that, The refractive index ND1 of the first lens > 1.

6.

4. A 3G3P wide-angle lens according to claim 1, characterized in that, The refractive index ND3 of the third lens > 1.

8.

5. A 3G3P wide-angle lens according to claim 1, characterized in that, The Abbe number VD3 of the third lens < 30.

6. A 3G3P wide-angle lens according to claim 1, characterized in that, The Abbe number VD5 of the fifth lens < 35.

7. A 3G3P wide-angle lens according to claim 1, characterized in that, The focal length f1 of the first lens and the focal length f of the wide-angle lens satisfy -11 < f1 / f < -5.

Images