Traffic lens and imaging device

Abstract

The invention relates to the field of optics, in particular to a traffic lens which is sequentially composed of a fixed lens group with positive focal power, a focusing lens group with negative focal power and a compensation lens group with positive focal power from the object plane side to the image plane side. The focusing lens group is a first focusing lens with negative focal power; lenses of the compensation lens group are all single lenses. The traffic lens satisfies the following conditional expressions: fno is less than 1.3; f / TTL > 2; wherein fno is the aperture number of the traffic lens, f is the focal length of the traffic lens, and TTL is the total optical length of the traffic lens. The large aperture effect of the traffic lens is achieved, the good resolving power is achieved, and the night shooting effect of the traffic lens is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optics, in particular to a traffic lens and an imaging device. BACKGROUND

[0002] In the intelligent traffic system, the accuracy of information acquisition directly depends on the accurate collection of image data by the front-end camera and the lens assembled therewith.

[0003] In view of the special requirements of the system on performance, the configured lens needs to exhibit performance characteristics beyond the conventional, specifically, low distortion, large target surface, large light transmission and high resolution.

[0004] Due to the small size of the traffic lens, the current traffic lens has weak infrared confocal performance when used at night, and the image quality obtained by night shooting is low, which cannot meet the requirements of users. SUMMARY

[0005] The present application will solve the existing technical problems, provide a traffic lens and an imaging device, realize the effect of large aperture of the traffic lens, have good resolution, and realize the effect of night shooting of the traffic lens.

[0006] The technical scheme provided by the present application is as follows:

[0007] A traffic lens, which comprises, from the object side to the image side, a fixed lens group with positive focal power, a focusing lens group with negative focal power and a compensation lens group with positive focal power;

[0008] The focusing lens group is a first focusing lens with negative focal power;

[0009] The lenses of the compensation lens group are all single lenses;

[0010] The traffic lens satisfies the following conditional formula:

[0011] fno < 1.3;

[0012] f / TTL > 2;

[0013] Wherein, fno is the aperture number of the traffic lens, f is the focal length of the traffic lens, and TTL is the total optical length of the traffic lens.

[0014] Through the above structure and parameter limitation, the effect of large aperture of the traffic lens is realized, the traffic lens has good resolution, and the effect of night shooting of the traffic lens is realized.

[0015] Preferably, the fixed lens group comprises, in order from the object side to the image side, a first fixed lens with positive focal power, a second fixed lens with positive focal power, a third fixed lens with positive focal power, a fourth fixed lens with positive focal power, and a fifth fixed lens with negative focal power, and the fourth fixed lens and the fifth fixed lens are cemented.

[0016] Preferably, the compensation lens group comprises, in order from the object side to the image side, a first compensation lens with negative focal power, a second compensation lens with positive focal power, a third compensation lens with negative focal power, a fourth compensation lens with positive focal power, a fifth compensation lens with positive focal power, a sixth compensation lens with negative focal power, and a seventh compensation lens with positive focal power.

[0017] Preferably, the focusing lens group is movable along the main optical axis of the traffic lens for adjusting the object distance of the traffic lens.

[0018] Preferably, the fourth compensation lens is a lenticular lens.

[0019] By arranging the lenticular lens, the optical path in the traffic lens is optimized, the radial width of the traffic lens is reduced, and the traffic lens is miniaturized.

[0020] Preferably, the traffic lens satisfies the following condition formula:

[0021] TTL / XG2> 200;

[0022] XG2 is the maximum movement distance of the focusing lens group.

[0023] By limiting the movement distance of the focusing lens group, the movement range of the focusing lens group is reduced, the volume of the traffic lens is reduced, and the traffic lens is miniaturized.

[0024] Preferably, the traffic lens satisfies the following condition formula:

[0025] 0.85 < fG2 / f < 0.9;

[0026] wherein fG2 is the focal length of the focusing lens group.

[0027] By limiting the focal length of the focusing lens group, the possibility of excessive traffic lens aberration and coma is reduced, and the resolving power of the traffic lens is increased.

[0028] Preferably, the traffic lens satisfies the following condition formula:

[0029] fc4 / f > 1.2;

[0030] wherein fc4 is the focal length of the fourth compensation lens.

[0031] The traffic lens satisfies the following condition formula:

[0032] fc4 / f>1.2;

[0033] Wherein, fc4 is the focal length of the fourth compensation lens.

[0034] One of the purposes of the present application is also to provide an imaging device, comprising: a traffic lens; and an imaging element configured to receive an image formed by the traffic lens.

[0035] Compared with the prior art, the traffic lens and the imaging device provided by the present application have the following beneficial effects:

[0036] 1. Through the above structure and parameter limitation, on the basis of realizing the miniaturization of the traffic lens, the full-range infrared confocal effect is also realized, and the resolving power of the traffic lens is increased.

[0037] 2. Through the use of a small amount of aspherical lenses, the relative difference of the traffic lens is reduced, and the number of lenses in the traffic lens is also reduced, realizing the miniaturization of the traffic lens.

[0038] 3. Through the limitation of the Abbe number of the first lens and the second lens, the chromatic aberration of the first lens group is reduced, and the imaging quality of the traffic lens is increased. BRIEF DESCRIPTION OF DRAWINGS

[0039] The above characteristics, technical features, advantages and implementation modes of the traffic lens and the imaging device will be further described in a clear and easy-to-understand manner in combination with the preferred embodiments and the accompanying drawings.

[0040] Figure 1 is a structural schematic diagram of a traffic lens of the present application;

[0041] Figure 2 is an aberration diagram of a traffic lens of the present application;

[0042] Figure 3 is a coma diagram of a traffic lens of the present application Figure 1 ;

[0043] Figure 4 is a coma diagram of a traffic lens of the present application Figure 2 .

[0044] BRIEF DESCRIPTION OF DRAWINGS: G1, fixed lens group; G2, focusing lens group; G3, compensation lens group; G4, auxiliary assembly; a1, first fixed lens; a2, second fixed lens; a3, third fixed lens; a4, fourth fixed lens; a5, fifth fixed lens; b1, first focusing lens; c1, first compensation lens; c2, second compensation lens; c3, third compensation lens; c4, fourth compensation lens; c5, fifth compensation lens; c6, sixth compensation lens; c7, seventh compensation lens; STO, diaphragm; CG, protective glass. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0047] Example 1

[0048] like Figures 1 to 4 As shown, a traffic lens is composed of a fixed lens group G1 with positive optical power, a focusing lens group G2 with negative optical power, and a compensating lens group G3 with positive optical power, arranged sequentially from the object plane side to the image plane side.

[0049] The focusing lens group G2 is a first focusing lens b1 with negative optical power;

[0050] All lenses in the compensation lens group G3 are single lenses;

[0051] The traffic camera satisfies the following condition:

[0052] fno < 1.3;

[0053] f / TTL > 2;

[0054] Where fno is the aperture number of the traffic lens, f is the focal length of the traffic lens, and TTL is the total optical length of the traffic lens.

[0055] In this embodiment, by limiting the structure and parameters described above, a large aperture effect for the traffic lens is achieved, resulting in better resolution and enabling nighttime shooting of the traffic lens.

[0056] The fixed lens group G1 consists of a first fixed lens a1 with positive optical power, a second fixed lens a2 with positive optical power, a third fixed lens a3 with positive optical power, a fourth fixed lens a4 with positive optical power, and a fifth fixed lens a5 with negative optical power, from the object plane side to the image plane side. The fourth fixed lens a4 and the fifth fixed lens a5 are cemented together.

[0057] The compensation lens group G3 is composed of a first compensation lens c1 with negative focal length, a second compensation lens c2 with positive focal length, a third compensation lens c3 with negative focal length, a fourth compensation lens c4 with positive focal length, a fifth compensation lens c5 with positive focal length, a sixth compensation lens c6 with negative focal length, and a seventh compensation lens c7 with positive focal length in order from the object side to the image side.

[0058] The focusing lens group G2 is moved along the main optical axis direction of the traffic lens for adjusting the object distance of the traffic lens.

[0059] The fourth compensation lens c4 is a lenticular lens.

[0060] In the embodiment, the light path in the traffic lens is optimized by the lenticular lens, the radial width of the traffic lens is reduced, and the miniaturization of the traffic lens is realized.

[0061] The traffic lens satisfies the following conditional expression:

[0062] TTL / XG2> 200;

[0063] XG2 is the maximum moving distance of the focusing lens group G2.

[0064] By limiting the moving distance of the focusing lens group G2, the moving range of the focusing lens group G2 is reduced, the volume of the traffic lens is reduced, and the miniaturization of the traffic lens is realized.

[0065] The traffic lens satisfies the following conditional expression:

[0066] 0.85 < fG2 / f < 0.9;

[0067] Wherein, fG2 is the focal length of the focusing lens group G2.

[0068] By limiting the focal length of the focusing lens group G2, the possibility of excessive traffic lens aberration and coma is reduced, and the resolving power of the traffic lens is increased.

[0069] The traffic lens satisfies the following conditional expression:

[0070] fc4 / f > 1.2;

[0071] Wherein, fc4 is the focal length of the fourth compensation lens c4.

[0072] By limiting the focal length of the fourth compensation lens c4, the focal length of the object and image side lenses of the fourth compensation lens c4 is optimized, the possibility of excessive focal length of the two side lenses is reduced, and the traffic lens aberration and coma are reduced, and the resolving power of the traffic lens is increased.

[0073] Embodiment 2

[0074] AsFigures 1 to 4 A traffic lens, as shown, is composed of a fixed lens group G1 of positive focal power, a focusing lens group G2 of negative focal power, a compensation lens group G3 of positive focal power and an auxiliary assembly G4 from the object side to the image side in order;

[0075] The fixed lens group G1 is composed of a first fixed lens a1 of positive focal power, a second fixed lens a2 of positive focal power, a third fixed lens a3 of positive focal power, a fourth fixed lens a4 of positive focal power, a fifth fixed lens a5 of negative focal power from the object side to the image side in order, and the fourth fixed lens a4 and the fifth fixed lens a5 are cemented.

[0076] The compensation lens group G3 is composed of a first compensation lens c1 of negative focal power, a second compensation lens c2 of positive focal power, a third compensation lens c3 of negative focal power, a fourth compensation lens c4 of positive focal power, a fifth compensation lens c5 of positive focal power, a sixth compensation lens c6 of negative focal power, a seventh compensation lens c7 of positive focal power from the object side to the image side in order.

[0077] The auxiliary assembly G4 is a protective glass CG.

[0078] The basic lens data of the traffic lens of the present embodiment is shown in Table 1, and the variable parameters in Table 1 are shown in Table 2.

[0079] The face number column shows the face number when the face on the object side is set as the first face and the number is increased one by one as it goes toward the image side; the surface type column shows the surface type of a certain lens; the curvature radius column shows the curvature radius of a certain lens, and the curvature radius is positive when the surface is curved toward the object side, and the curvature radius is negative when the surface is curved toward the image side; the center thickness column shows the face spacing on the optical axis of each face and the face adjacent to it on the image side; the refractive index column shows the refractive index of a certain lens; and the Abbe number column shows the Abbe number of a certain lens.

[0080] In Table 2, the WIDE column shows the specific values of each variable parameter when the traffic lens is in the wide-angle end state, and the TELE column shows the specific values of each variable parameter when the traffic lens is in the telephoto end state.

[0081]

Table 1

[0082]

[0083]

[0084]

Table 2

[0085] object distance INF 23M 15M D1 0.85 1.1 1.25 D2 4.94 4.69 4.54

[0086] In this embodiment, f = 55.58 mm, fno = 1.2, TTL = 115.01 mm, f / TTL = 2.07;

[0087] Wherein, fno is the aperture number of the traffic lens, f is the focal length of the traffic lens, and TTL is the total optical length of the traffic lens.

[0088] XG2 = 0.4 mm, TTL / XG2 = 287;

[0089] XG2 is the maximum moving distance of the focusing lens group G2.

[0090] fG2 = -49.65 mm, fG2 / f = 0.893;

[0091] Wherein, fG2 is the focal length of the focusing lens group G2.

[0092] fc4 = 74.38 mm, fc4 / f = 1.34;

[0093] Wherein, fc4 is the focal length of the fourth compensation lens c4.

[0094] Embodiment 3

[0095] An imaging device, as shown in Figures 1 to 4 includes the traffic lens as described in any of the above embodiments, and an imaging element configured to receive an image formed by the traffic lens.

[0096] It should be noted that the above embodiments can be freely combined as needed. The above description is only the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can also be considered as the protection scope of the present application.

Claims

1. A traffic camera, characterized in that, The traffic camera consists of a fixed lens group with positive optical power, a focusing lens group with negative optical power, and a compensating lens group with positive optical power, arranged sequentially from the object plane side to the image plane side. The focusing lens group is a first focusing lens with negative optical power; All lenses in the compensation lens group are single lenses; The traffic camera satisfies the following condition: fno < 1.3; f / TTL > 2; Where fno is the aperture number of the traffic lens, f is the focal length of the traffic lens, and TTL is the total optical length of the traffic lens.

2. A traffic camera according to claim 1, characterized in that: The fixed lens group consists of a first fixed lens with positive optical power, a second fixed lens with positive optical power, a third fixed lens with positive optical power, a fourth fixed lens with positive optical power, and a fifth fixed lens with negative optical power, arranged sequentially from the object plane side to the image plane side. The fourth fixed lens and the fifth fixed lens are cemented together.

3. A traffic camera according to claim 1, characterized in that: The compensation lens group consists of a first compensation lens with negative optical power, a second compensation lens with positive optical power, a third compensation lens with negative optical power, a fourth compensation lens with positive optical power, a fifth compensation lens with positive optical power, a sixth compensation lens with negative optical power, and a seventh compensation lens with positive optical power, arranged sequentially from the object plane side to the image plane side.

4. A traffic camera according to claim 1, characterized in that: The focusing lens group moves along the main optical axis of the traffic lens to adjust the object distance of the traffic lens.

5. A traffic camera according to claim 3, characterized in that: The fourth compensation lens is a biconvex lens.

6. A traffic camera according to claim 1, characterized in that: The traffic camera satisfies the following condition: TTL / XG2 > 200; XG2 is the maximum moving distance of the focusing lens group.

7. A traffic camera according to claim 1, characterized in that: The traffic camera satisfies the following condition: 0.85 < fG2 / f < 0.9; Wherein, fG2 is the focal length of the focusing lens group.

8. A traffic camera according to claim 5, characterized in that: The traffic camera satisfies the following condition: fc4 / f > 1.2; Wherein, fc4 is the focal length of the fourth compensation lens.

9. An imaging device, characterized in that, include: Traffic camera as described in any one of claims 1 to 8; An imaging element is configured to receive an image formed by the traffic lens.

Images