Optical imaging system

Abstract

The utility model discloses an optical imaging system which comprises a first lens optical imaging system, a second lens optical imaging system and a third lens optical imaging system which are sequentially arranged from an object plane to an image plane. The first lens optical imaging system has positive bending force, the second lens optical imaging system has negative bending force, and the image surface of the second lens optical imaging system is an aspheric surface; the third lens optical imaging system has positive bending force, and the image surface of the third lens optical imaging system is an aspheric surface; according to the utility model, the first lens provides positive focal power for the optical system, so that the optical pick-up lens has the characteristics of wide viewing angle and low sensitivity; the second lens provides negative focal power for the optical system, the aberration of the optical system can be effectively corrected, the imaging quality of the optical system is improved, and therefore the high-definition imaging optical system is obtained. The third lens is favorable for compensating for the problem of over-correction or insufficient correction of the object-side optical system.

Description

Technical Field

[0001] This utility model relates to the field of camera technology, specifically to an optical imaging system, and particularly to a camera lens composed of three optical elements built into a camera device used in intelligent monitoring and home appliances with added camera functions. Background Technology

[0002] In recent years, intelligent imaging and intelligent surveillance have flourished, and video surveillance systems are indispensable for ensuring the safety of people's daily lives and national security. Especially for nighttime security systems, coupled with the current trend of electronic products being both functional and lightweight, low-cost camera lenses with good image quality have become the mainstream in the market.

[0003] Traditional high-resolution, miniaturized photographic lenses used in electronic devices typically employ multi-element lens structures, which increases the cost of the imaging system. Furthermore, the increasing trend towards larger apertures in photographic lenses in recent years has made it difficult for traditional lens-based optical systems to simultaneously meet the demands of large apertures, high resolution, and lightweight design. Therefore, providing a high-resolution optical system that combines large apertures is one of the problems the industry is currently trying to solve. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides an optical imaging system.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0006] This utility model discloses an optical imaging system, comprising a first lens optical imaging system, a second lens optical imaging system, and a third lens optical imaging system arranged sequentially from the object plane to the image plane; the first lens optical imaging system has positive refractive force, the second lens optical imaging system has negative refractive force, and the image plane of the second lens optical imaging system is aspherical; the third lens optical imaging system has positive refractive force, and the image plane of the third lens optical imaging system is aspherical; and the system also includes an aperture stop disposed within the optical imaging system.

[0007] In a preferred embodiment of this invention, the focal length of the first lens optical imaging system is f1, and the focal length of the optical imaging system is f, which satisfies the following conditions:

[0008] 0 <f1 / f<1。

[0009] In a preferred embodiment of this invention, the focal length of the second lens optical imaging system is f2, and the focal length of the optical imaging system is f, which satisfies the following conditions:

[0010] -1 <f2 / f<0。

[0011] In a preferred embodiment of this invention, the object-side surface curvature radius of the third lens is R4, and the distance from the object-side surface of the third lens to the imaging surface on the optical axis is D4, satisfying the following conditions:

[0012] 9 <R4 / D4<50。

[0013] In a preferred embodiment of this invention, the focal length of the third lens is f3, and the focal length of the optical imaging system is f, satisfying the following conditions:

[0014] 0.3 <f3 / f<1.2。

[0015] As a preferred embodiment of this invention, the optical imaging system has a maximum imaging field of view (FOV) and a sensor imaging height corresponding to the FOV, which satisfies the following conditions:

[0016] 2 <FOV / IMGH<3。

[0017] In a preferred embodiment of this invention, the distance from the object-side surface of the first lens to the imaging surface on the optical axis is TTL, and the distance from the image-side surface of the first lens to the object-side surface of the second lens on the optical axis is D3, satisfying the following conditions:

[0018] 6 <TTL / D3<21。

[0019] In a preferred embodiment of this invention, the focal length of the third lens is f3, and the center thickness of the third lens is D6, which satisfies the following conditions:

[0020] 2 <f3 / D6<12。

[0021] As a preferred embodiment of this invention, the object-side and image-side surfaces of the first lens optical imaging system are spherical lenses.

[0022] As a preferred embodiment of this invention, the object side of the second lens optical imaging system is spherical, and the image side is an aspherical lens.

[0023] The beneficial effects of this utility model are:

[0024] 1. In this optical imaging system, the object-side and image-side of the first lens are both spherical lenses, providing positive optical power to the optical system and giving the optical camera lens wide viewing angle and low sensitivity. The object-side of the second lens is spherical, while the image-side is aspherical, providing negative optical power to the optical system. This can effectively correct the aberrations of the optical system, improve the imaging quality of the optical system, and thus obtain a high-definition imaging optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings are used to provide a further understanding of the present utility model, and constitute a part of the specification. Together with the embodiments of the present utility model, they are used to explain the present utility model, but do not constitute a limitation to the present utility model. In the drawings:

[0026] Figure 1 is a schematic structural diagram of an optical imaging system in Embodiment 1 of the present utility model;

[0027] Figure 2 is a schematic structural diagram of an optical imaging system in Embodiment 2 of the present utility model;

[0028] Figure 3 is a system parameter chart of an optical imaging system in Embodiment 1 of the present utility model;

[0029] Figure 4 is a system parameter chart of an optical imaging system in Embodiment 2 of the present utility model;

[0030] Figure 5 is a parameter table of the value range of 0 < f1 / f < 1 in the embodiments of the present utility model;

[0031] Figure 6 is a parameter table of the value range of 1 < f2 / f < 0 in the embodiments of the present utility model;

[0032] Figure 7 is a parameter table of the value range of 0.3 < f3 / f < 1.2 in the embodiments of the present utility model;

[0033] Figure 8 is a parameter table of the value range of 2 < FOV / IMGH < 3 in the embodiments of the present utility model;

[0034] Figure 9 is a parameter table of the value range of 6 < TTL / D3 < 21 in the embodiments of the present utility model;

[0035] Figure 10 is a parameter table of the value range of 2 < f3 / D6 < 12 in the embodiments of the present utility model.

[0036] In the figure: 1. First lens; 2. Second lens; 3. Third lens; 4. Aperture. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The following is a description of the preferred embodiments of the present utility model with reference to the drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present utility model, and are not used to limit the present utility model.

[0038] Embodiment 1: As Figure 1 and Figure 2 As shown, this utility model discloses an optical imaging system, comprising a first lens 1, a second lens 2, and a third lens 3 arranged sequentially from the object plane to the image plane; the first lens 1 has positive refractive power, the second lens 2 has negative refractive power, and the image plane of the second lens 2 is aspherical; the third lens 3 has positive refractive power, and the image plane of the third lens 3 is aspherical; the system also includes an aperture 4 disposed within the optical imaging system. Figure 2 This is a system parameter chart of the optical imaging system. Both sides of the third lens 3 are convex.

[0039] Wherein, the focal length of the first lens 1 is f1, and the focal length of the optical camera lens group is f, which satisfies the following condition: 0 <f1 / f<1。

[0040] Both the object-side and image-side surfaces of the first lens are spherical lenses, providing positive optical power to the optical system and giving the optical camera lens wide viewing angle and low sensitivity.

[0041] Wherein, the focal length of the second lens 2 is f2, and the focal length of the optical camera lens group is f, which satisfies the following condition: -1 <f2 / f<0.。

[0042] The second lens has a spherical object side and aspherical image sides, providing negative optical power to the optical system. This effectively corrects aberrations in the optical system, improves imaging quality, and thus achieves a high-definition imaging optical system.

[0043] The object-side surface radius of curvature of the third lens 3 is R4, and the distance from the object-side surface of the lower third lens to the imaging plane on the optical axis is D4, which satisfies the following condition: 9 <R4 / D4<50。

[0044] By setting the conditions for the curvature radius and center thickness of the object side of the third lens 3, it is beneficial to compensate for the overcorrection or undercorrection of the object side optical system, and it is more conducive to the high-quality and clear imaging of the optical system.

[0045] Wherein, the focal length of the third lens is f3, and the focal length of the optical camera lens group is f, which satisfies the following conditions:

[0046] 0.3 <f3 / f<1.2。

[0047] Setting the conditional lower limit helps reduce the angle at which the principal rays from peripheral viewpoints incident on the image plane, allowing the optical system to obtain a suitable imaging field of view. Setting the conditional upper limit helps to easily suppress astigmatism and achieve high-quality, clear image quality.

[0048] The optical imaging system has a maximum imaging field of view (FOV) and a sensor imaging height (IMGH) corresponding to the FOV, satisfying the following condition: 2 <FOV / IMGH<3。

[0049] Effectively setting the imaging range of the optical system is beneficial to the physical application of the optical system and to the uniform imaging of the corresponding pixel positions of the sensor.

[0050] Wherein, the distance on the optical axis from the object side surface of the first lens 1 to the imaging surface is TTL, and the distance on the optical axis from the image side surface of the first lens to the object side surface of the second lens is D3, which satisfies the following conditions:

[0051] 6 <TTL / D3<21

[0052] By rationally configuring the air gaps in the optical system, the system structure can be made compact, and the stability of the imaging optical system structure can be increased.

[0053] The third lens has a focal length of f3 and a center thickness of D6, satisfying the following condition: 2 <f3 / D6<12。

[0054] By satisfying certain conditions, a third lens that provides positive refractive force to the system can increase the imaging field of view of the optical system, thereby achieving the desired imaging field of view.

[0055] Example 2: Figure 3 The present invention discloses an optical imaging system, comprising a first lens 1, a second lens 2, and a third lens 3 arranged sequentially from the object plane to the image plane; the first lens 1 has positive refractive power, the second lens 2 has negative refractive power, and the image plane of the second lens 2 is aspherical; the third lens 3 has positive refractive power, and the image plane of the third lens 3 is aspherical; the system also includes an aperture stop disposed within the optical imaging system. Figure 4 This is a system parameter chart for the optical imaging system. The third lens 3 has two convex and concave surfaces. The specific parameter tables related to Embodiments 1 and 2 are as follows... Figures 5-10 As shown.

[0056] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An optical imaging system, characterized in that, It includes a first lens (1), a second lens (2) and a third lens (3) arranged sequentially from the object plane to the image plane; the first lens (1) has positive refractive power, the second lens (2) has negative refractive power, and the image plane of the second lens (2) is aspherical; the third lens (3) has positive refractive power, and the image plane of the third lens (3) is aspherical, and it also includes an aperture (4) disposed in the optical imaging system.

2. The optical imaging system according to claim 1, characterized in that, The focal length of the first lens (1) is f1, and the focal length of the optical imaging system is f, which satisfies the following conditions: 0 <f1 / f<1。 3. The optical imaging system according to claim 1, characterized in that, The focal length of the second lens (2) is f2, and the focal length of the optical imaging system is f, which satisfies the following conditions: -1 <f2 / f<0。 4. An optical imaging system according to claim 3, characterized in that, The third lens has an object-side surface curvature radius of R4, and the distance from the object-side surface of the third lens to the imaging surface on the optical axis is D4, satisfying the following conditions: 9 <R4 / D4<50。 5. An optical imaging system according to claim 4, characterized in that, The focal length of the third lens is f3, and the focal length of the optical imaging system is f, which satisfies the following conditions: 0.3 <f3 / f<1.2。 6. An optical imaging system according to claim 5, characterized in that, The optical imaging system described above has a maximum imaging field of view (FOV) and a sensor imaging height (IMGH) corresponding to the imaging field of view, which satisfies the following conditions: 2 <FOV / IMGH<3。 7. An optical imaging system according to claim 1, characterized in that, The distance on the optical axis from the object-side surface of the first lens to the imaging surface is TTL, and the distance on the optical axis from the image-side surface of the first lens to the object-side surface of the second lens is D3, which satisfies the following conditions: 6 <TTL / D3<21。 8. An optical imaging system according to claim 5, characterized in that, The third lens has a focal length of f3 and a center thickness of D6, and satisfies the following conditions: 2 <f3 / D6<12。 9. An optical imaging system according to claim 1, characterized in that, The object-side surface and image-side surface of the first lens (1) are spherical lenses.

10. An optical imaging system according to claim 1, characterized in that, The object side of the second lens (2) is spherical, and the image side is aspherical.

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