A surveillance lens

Abstract

The present invention provides a surveillance lens, comprising: a diaphragm, a first lens to an eighth lens sequentially arranged from the object surface side to the image surface side, a filter and a sensor; the first surface of the first lens is concave, and the second surface is concave; the third surface of the second lens is convex, and the fourth surface is convex; the fifth surface of the third lens is concave, and the sixth surface is concave; the seventh surface of the fourth lens is convex, and the eighth surface is convex; the ninth surface of the fifth lens is convex, and the tenth surface is concave or convex; the eleventh surface of the sixth lens is convex, and the twelfth surface is convex; the thirteenth surface of the seventh lens is concave, and the fourteenth surface is concave; the fifteenth surface of the eighth lens is convex, and the sixteenth surface is concave. Thus, under the condition of relatively low illuminance, the clarity of the surveillance image captured by the surveillance lens is relatively high.

Description

Technical Field

[0001] The present application relates to the field of monitoring technologies, and particularly to a monitoring lens. Background Art

[0002] A monitoring lens refers to the lens of a monitoring camera. In related technologies, the aperture of a monitoring lens is usually small. Under the condition of low illuminance, the clarity of the monitoring image captured by the monitoring lens is low.

[0003] Therefore, it is necessary to provide a new monitoring lens so that the monitoring lens can still capture a monitoring image with high clarity under the condition of low illuminance. Summary of the Invention

[0004] To solve the technical problem that in the related technologies, the clarity of the monitoring image captured by the monitoring lens is low under the condition of low illuminance, an embodiment of the present invention provides a monitoring lens, including: a diaphragm, and a first lens to an eighth lens, a filter, and a sensor sequentially arranged from the object surface side to the image surface side;

[0005] The first surface of the first lens on the object surface side is concave, and the second surface of the first lens on the image surface side is concave;

[0006] The third surface of the second lens on the object surface side is convex, and the fourth surface of the second lens on the image surface side is convex;

[0007] The fifth surface of the third lens on the object surface side is concave, and the sixth surface of the third lens on the image surface side is concave;

[0008] The seventh surface of the fourth lens on the object surface side is convex, and the eighth surface of the fourth lens on the image surface side is convex;

[0009] The ninth surface of the fifth lens on the object surface side is convex, and the tenth surface of the fifth lens on the image surface side is concave or convex;

[0010] The eleventh surface of the sixth lens on the object surface side is convex, and the twelfth surface of the sixth lens on the image surface side is convex;

[0011] The thirteenth surface of the seventh lens on the object surface side is concave, and the fourteenth surface of the seventh lens on the image surface side is concave;

[0012] The fifteenth surface of the eighth lens on the object surface side is convex, and the sixteenth surface of the eighth lens on the image surface side is concave.

[0013] Optionally, the diaphragm is arranged between the second lens and the third lens.

[0014] Optionally, the distance between the sixth surface of the third lens and the seventh surface of the fourth lens is 0.

[0015] Optionally, the distance between the fourteenth surface of the seventh lens and the fifteenth surface of the eighth lens is 0.

[0016] Optionally, the sixth lens is an aspherical lens.

[0017] Optionally, the radius of curvature R11 of the second surface of the first lens and the radius of curvature R12 of the first surface of the first lens satisfy the following condition: 2 < |R11 / R12| < 4.

[0018] Optionally, the focal length F2 of the second lens and the focal length F5 of the fifth lens satisfy the following condition: 0.8 < F2 / F5 < 1.2.

[0019] Optionally, the focal length F4 of the fourth lens and the focal length F3 of the third lens satisfy the following condition: -2 < F4 / F3 < -0.8.

[0020] Optionally, the radius of curvature R81 of the fifteenth surface of the eighth lens and the radius of curvature R82 of the sixteenth surface of the eighth lens satisfy: 2 < R82 / R81 < 6.

[0021] Optionally, the distance TTL from the first surface of the first lens to the sensor and the focal length F of the monitoring lens satisfy the following condition: 3 < TTL / F < 4.8.

[0022] Optionally, the front aperture D of the monitoring lens, the maximum field of view FOV of the monitoring lens, and the image height H corresponding to the maximum field of view of the monitoring lens satisfy the following condition: 0.01 < D / H / FOV < 0.04.

[0023] Optionally, the aspherical mirror surface of the aspherical lens satisfies the following conditions:

[0024]

[0025] Where Z(h) is the distance sagitta from the vertex of the aspherical surface at the position with height h along the optical axis direction, c = 1 / r, r represents the radius of curvature of the aspherical mirror surface, k is the conic coefficient, and A, B, C, D, E are the high-order aspherical coefficients.

[0026] Optionally, the convexity of the eighth lens is greater than the concavity.

[0027] The monitoring lens provided by an embodiment of the present invention includes: a diaphragm, and first to eighth lenses, a filter, and a sensor sequentially arranged from the object side to the image side; by arranging the first to eighth lenses with specific shapes, it is beneficial to increase the light flux of the monitoring lens, so as to achieve higher clarity of the monitoring image captured by the monitoring lens under conditions of lower illuminance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is a schematic diagram of a monitoring lens provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0031] In order to solve the technical problem that the clarity of the monitoring image captured by the monitoring lens is low under conditions of lower illuminance in the related art, an embodiment of the present invention provides a monitoring lens.

[0032] As Figure 1 shown, the monitoring lens provided by an embodiment of the present invention may include: a diaphragm 10, and first to eighth lenses 21 to 28, a filter 30, and a sensor 40 sequentially arranged from the object side to the image side.

[0033] It can be understood that the side close to the first lens 21 is the object side, and the plane where the sensor 40 is located is the image side.

[0034] Specifically, the first surface of the first lens 21 on the object side is a concave surface, and the second surface of the first lens 21 on the image side is a concave surface, that is, the first lens has a negative focal power. By setting both the first surface and the second surface of the first lens as concave surfaces, it is beneficial to reduce the front aperture of the monitoring lens, increase the light flux of the monitoring lens, and thus be beneficial to the monitoring lens to capture a monitoring image with higher clarity under conditions of lower illuminance.

[0035] The third surface of the second lens 22 on the object side is convex, and the fourth surface of the second lens 22 on the image side is convex, that is, the second lens has a positive optical power. By setting both the third surface and the fourth surface of the second lens to be convex, the function of transitioning light rays is achieved, thereby increasing the light flux of the surveillance lens, which is beneficial for the surveillance lens to capture surveillance images with higher clarity under conditions of lower illumination.

[0036] The fifth surface of the third lens 23 on the object side is concave, and the sixth surface of the third lens 23 on the image side is concave, that is, the third lens has a negative optical power.

[0037] In one embodiment, the aperture stop 10 can be disposed between the second lens 22 and the third lens 23, that is, at a position closer to the front of the optical system of the surveillance lens, further reducing the front aperture diameter of the surveillance lens and increasing the light flux of the surveillance lens, so that it is beneficial for the surveillance lens to capture surveillance images with higher clarity under conditions of lower illumination.

[0038] The seventh surface of the fourth lens 24 on the object side is convex, and the eighth surface of the fourth lens 24 on the image side is convex, that is, the fourth lens has a positive optical power.

[0039] In one embodiment, the distance between the sixth surface of the third lens and the seventh surface of the fourth lens is 0. In this way, the third lens and the fourth lens are bonded together, and the third lens and the fourth lens form an achromatic lens group to facilitate reducing the chromatic aberration of the light rays transmitted by the first lens and the second lens, thereby improving the resolution of the surveillance images captured by the surveillance lens. Moreover, bonding the third lens and the fourth lens together is beneficial for reducing the tolerance sensitivity of the optical system of the surveillance lens, and thus facilitating the assembly of high-quality surveillance lenses.

[0040] The ninth surface of the fifth lens 25 on the object side is convex, and the tenth surface of the fifth lens 25 on the image side is concave or convex. Specifically, the fifth lens has a positive optical power. Whether the tenth surface is convex or concave when the ninth surface of the fifth lens is convex is convenient for smoothly transitioning light rays to the sixth lens, that is, the fifth lens has the function of transitioning light rays, thereby increasing the light flux of the surveillance lens, which is beneficial for the surveillance lens to capture surveillance images with higher clarity under conditions of lower illumination.

[0041] The eleventh surface of the sixth lens 26 on the object side is convex, and the twelfth surface of the sixth lens 26 on the image side is convex, that is, the sixth lens has a positive optical power. By setting the eleventh surface and the twelfth surface of the sixth lens to be convex, it is beneficial for smoothly transitioning light rays to the seventh lens 27, thereby increasing the light flux of the surveillance lens, which is beneficial for the surveillance lens to capture surveillance images with higher clarity under conditions of lower illumination.

[0042] Moreover, in one embodiment, the sixth lens is an aspherical lens, which helps correct the aberration of marginal rays generated by the first to fifth lenses, improves the resolution of the optical system of the surveillance lens, and thus enhances the resolution of the surveillance images captured by the surveillance lens.

[0043] Furthermore, the aspherical surface of the aspherical lens satisfies the following conditions:

[0044]

[0045] where Z(h) is the sagitta, the distance from the vertex of the aspherical surface to the aspherical surface along the optical axis at the position with height h, c = 1 / r, r represents the radius of curvature of the aspherical surface, k is the conic constant, and A, B, C, D, and E are the higher-order aspherical coefficients.

[0046] The thirteenth surface of the seventh lens 27 on the object side is concave, and the fourteenth surface of the seventh lens 27 on the image side is concave, that is, the sixth lens has a negative focal power. By setting the thirteenth and fourteenth surfaces of the seventh lens as concave surfaces, it is beneficial to reduce the total length of the surveillance lens, thereby reducing the volume of the surveillance lens and facilitating the design of the surveillance lens.

[0047] In one embodiment, the distance between the fourteenth surface of the seventh lens and the fifteenth surface of the eighth lens is 0. In this way, the seventh lens and the eighth lens are bonded together, and the seventh lens and the eighth lens form an achromatic lens group, so as to reduce the chromatic aberration of the light transmitted by the fifth lens and the sixth lens, thereby improving the resolution of the surveillance images captured by the surveillance lens. Moreover, bonding the seventh lens and the eighth lens together is beneficial to reducing the tolerance sensitivity of the optical system of the surveillance lens, and thus facilitating the assembly of high-quality surveillance lenses.

[0048] The fifteenth surface of the eighth lens 28 on the object side is convex, and the sixteenth surface of the eighth lens 28 on the image side is concave. In one embodiment, the convexity of the eighth lens is greater than the concavity, that is, the eighth lens has a positive focal power. This helps reduce the rear aperture diameter and the overall length of the optical lens, contributing to the miniaturization of the surveillance lens.

[0049] Moreover, as an implementation manner of the embodiment of the present invention, the radius of curvature R11 of the second surface of the first lens and the radius of curvature R12 of the first surface of the first lens satisfy the following condition: 2 < |R11 / R12| < 4.

[0050] As an implementation manner of the embodiment of the present invention, the focal length F2 of the second lens and the focal length F5 of the fifth lens satisfy the following condition: 0.8 < F2 / F5 < 1.2.

[0051] As an implementation manner of an embodiment of the present invention, the focal length F4 of the fourth lens and the focal length F3 of the third lens satisfy the following condition: -2 < F4 / F3 < -0.8.

[0052] As an implementation manner of an embodiment of the present invention, the radius of curvature R81 of the fifteenth surface of the eighth lens and the radius of curvature R82 of the sixteenth surface of the eighth lens satisfy: 2 < R82 / R81 < 6.

[0053] As an implementation manner of an embodiment of the present invention, the distance TTL from the first surface of the first lens to the sensor and the focal length F of the surveillance lens satisfy the following condition: 3 < TTL / F < 4.8.

[0054] As an implementation manner of an embodiment of the present invention, the front aperture D of the surveillance lens, the maximum field of view FOV of the surveillance lens, and the image height H corresponding to the maximum field of view of the surveillance lens satisfy the following condition: 0.01 < D / H / FOV < 0.04.

[0055] By controlling the above parameters of the surveillance lens, the surveillance lens can capture a surveillance image with higher clarity under low illumination conditions; the resolution of the surveillance image is relatively high, and the volume of the surveillance lens is relatively small.

[0056] The surveillance lens provided by the embodiment of the present invention includes: a diaphragm, and the first lens to the eighth lens, a filter, and a sensor sequentially arranged from the object surface side to the image surface side; by arranging the first lens to the eighth lens with a specific shape, it is beneficial to increase the light flux of the surveillance lens, so as to achieve the effect that the clarity of the surveillance image captured by the surveillance lens is relatively high under relatively low illumination conditions.

[0057] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the element.

[0058] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0059] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention are all included in the protection scope of the present invention.

Claims

1. A monitoring lens, characterized in that, Including: a diaphragm, and a first lens to an eighth lens, a filter, and a sensor sequentially arranged from the object surface side to the image surface side. There are a total of eight lenses with diopter in the monitoring lens; The first surface of the first lens on the object surface side is concave, and the second surface of the first lens on the image surface side is concave; The third surface of the second lens on the object surface side is convex, and the fourth surface of the second lens on the image surface side is convex; The fifth surface of the third lens on the object surface side is concave, and the sixth surface of the third lens on the image surface side is concave; The seventh surface of the fourth lens on the object surface side is convex, and the eighth surface of the fourth lens on the image surface side is convex; The ninth surface of the fifth lens on the object surface side is convex, and the tenth surface of the fifth lens on the image surface side is concave or convex; The eleventh surface of the sixth lens on the object surface side is convex, and the twelfth surface of the sixth lens on the image surface side is convex; The thirteenth surface of the seventh lens on the object surface side is concave, and the fourteenth surface of the seventh lens on the image surface side is concave; The fifteenth surface of the eighth lens on the object surface side is convex, and the sixteenth surface of the eighth lens on the image surface side is concave; Wherein, the diaphragm is arranged between the second lens and the third lens, and the focal length F2 of the second lens and the focal length F5 of the fifth lens satisfy the following condition: 0.8 < F2 / F5 < 1.2; Wherein, the radius of curvature R81 of the fifteenth surface of the eighth lens and the radius of curvature R82 of the sixteenth surface of the eighth lens satisfy: 2 < R82 / R81 < 6.

2. The monitoring lens according to claim 1, characterized in that The radius of curvature R11 of the second surface of the first lens and the radius of curvature R12 of the first surface of the first lens satisfy the following condition: 2 < |R11 / R12| < 4.

3. The monitoring lens according to claim 1, wherein The focal length F4 of the fourth lens and the focal length F3 of the third lens satisfy the following condition: -2 < F4 / F3 < -0.

8.

4. The monitoring lens according to claim 1, characterized in that, The distance TTL from the first surface of the first lens to the sensor and the focal length F of the monitoring lens satisfy the following condition: 3 < TTL / F < 4.8.

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