阅读说明：本技术 光学镜头 (Optical lens ) 是由 陈嘉鸿 于 2018-09-04 设计创作，主要内容包括：一种光学镜头,光学镜头自物侧至像侧包含第一透镜、第二透镜、第三透镜、第四透镜、第五透镜、第六透镜、第七透镜及第八透镜,分别具有负、负、正、正、负、正、正及负屈光度。第一透镜的物侧表面的曲率半径大于像侧表面的曲率半径；第八透镜的像侧表面的有效半径是r并具有反曲点,反曲点与光轴的距离是H,第八透镜的像侧表面与光轴相交于一交点,反曲点映射至光轴的映射位置与交点的距离是d,|r/d|≤30及/或|r/H|≤2。本揭露所提出的光学镜头具有低畸变、大光圈、大视场角及小体积的特性。(An optical lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens from an object side to an image side, and the optical lens respectively has negative diopter, positive diopter, negative diopter, positive diopter and negative diopter. The curvature radius of the object side surface of the first lens is larger than that of the image side surface of the first lens; the effective radius of the image side surface of the eighth lens is r and has an inflection point, the distance between the inflection point and the optical axis is H, the image side surface of the eighth lens intersects with the optical axis at an intersection point, the distance between a mapping position of the inflection point mapped to the optical axis and the intersection point is d, | r/d | ≦ 30 and/or | r/H | ≦ 2. The optical lens proposed in the present disclosure has the characteristics of low distortion, large aperture, large field angle and small volume.)

1. An optical lens assembly, in order from an object side to an image side comprising:

a first lens having a negative diopter;

a second lens with negative diopter;

a third lens with positive diopter;

a fourth lens with positive diopter;

a fifth lens with negative diopter;

a sixth lens with positive diopter;

a seventh lens with positive diopter; and

an eighth lens having negative refractive power.

2. An optical lens assembly, in order from an object side to an image side comprising:

a first lens element with negative refractive power, the first lens element comprising an object-side surface having a radius of curvature R1 and an image-side surface having a radius of curvature R2, wherein R1/R2| ≧ 1;

a second lens with diopter;

a third lens with positive diopter;

a fourth lens with positive diopter;

a fifth lens with negative diopter;

a sixth lens with positive diopter;

a seventh lens with positive diopter; and

an eighth lens with diopter.

3. An optical lens assembly, in order from an object side to an image side along an optical axis, comprising:

a first lens having a negative diopter;

a second lens with diopter;

a third lens with positive diopter;

a fourth lens with positive diopter;

a fifth lens with negative diopter;

a sixth lens with positive diopter;

a seventh lens with positive diopter; and

an eighth lens element comprising an image-side surface having an inflection point, an effective radius of the image-side surface being r, the image-side surface having an intersection at the optical axis, the inflection point being separated from the optical axis by an H distance, the inflection point being mapped to a mapping position on the optical axis, the mapping position being separated from the intersection by a d distance, and | r/d | ≦ 30 and/or | r/H | ≦ 2.

4. An optical lens according to any one of claims 1 to 3, characterized in that the first lens, the second lens and the third lens have a positive refractive power as a whole, and/or the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens have a positive refractive power as a whole.

5. An optical lens according to any one of claims 1 to 3, characterized in that the first lens is a glass lens, and/or at least one of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens is a plastic lens or a glass lens.

6. An optical lens according to any one of claims 1 to 3, characterized in that it satisfies at least one of the following conditions: the first lens element is a convex-concave lens element, the second lens element is a concave lens element, the third lens element is a biconvex lens element, the fourth lens element is a biconvex lens element, the fifth lens element is a biconcave lens element, the sixth lens element is a biconvex lens element, the seventh lens element is a biconvex lens element, and the eighth lens element is a convex-concave lens element or a biconcave lens element.

7. An optical lens according to any one of claims 1 to 3, characterized in that the first lens is a spherical lens, and/or at least one of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens is an aspherical lens or a free-form lens.

8. An optical lens according to any one of claims 1 to 3, wherein the optical lens has a focal length of F, a total lens length of TTL, an image height of Y, an aperture value of FNO and a field of view of FOV, and satisfies at least one of the following conditions: F/TTL is less than or equal to 0.5, F/Y is less than or equal to 1, FNO TTL (percent F)/FOV Y (percent FOV)/Y (percent F) is less than or equal to 0, and FNO TTL (percent F)/FOV Y (percent FOV)/Y (percent FOV) is less than or equal to 0.3.

9. An optical lens element according to any one of claims 1 to 3, having a focal length F, wherein the image-side surface of the third lens element is separated from the object-side surface of the fourth lens element by a distance D, and wherein | F/D | is greater than or equal to 1.

10. An optical lens according to any one of claims 1 to 3, characterized in that the first lens has a refractive index N1, an Abbe number V1, the second lens has a refractive index N2, an Abbe number V2, the third lens has a refractive index N3, an Abbe number V3, the fourth lens has a refractive index N4, an Abbe number V4, the fifth lens has a refractive index N5, an Abbe number V5, the sixth lens has a refractive index N6, an Abbe number V6, the seventh lens has a refractive index N7, an Abbe number V7, the eighth lens has a refractive index N8, an Abbe number V8, and the optical lens satisfies at least one of the following conditions: n1 is not less than N2, N1 is not less than N4, N1 is not less than N5, N1 is not less than N6, N1 is not less than N7, N1 is not less than N8, N3 is not less than N2, V2 is not less than V1, V2 is not less than V3, V4 is not less than V1, V6 is not less than V1, V7 is not less than V1, V3 is not less than V5 and V3 is not less than V8.

Technical Field

The present invention relates to an optical lens, and more particularly, to an optical lens with low distortion, large aperture, large field angle and small volume.

Background

In recent years, due to the rise of random photographing activities in motion states, the demand for light, thin, short and small optical lenses has been greatly increased, and a wind for a small and high-quality image capturing device has also been brought.

Generally, an image capturing device used in a normal environment has a low flexibility in adjusting the image capturing parameters according to the environment. For example, the image capturing quality of the image capturing device cannot overcome the problem that the image angle is reduced and the resolution is reduced due to the change of the refractive index of the environmental medium, so that the image capturing device is difficult to meet the requirements of stable image quality and super wide angle. Therefore, it is desirable to provide a new optical lens and an electronic device, which can maintain a certain resolution according to the environmental factors under the premise of increasing the viewing angle or substantially maintaining the viewing angle.

Disclosure of Invention

In view of the above, an optical lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element. The first lens has a negative refractive power, the second lens has a negative refractive power, the third lens has a positive refractive power, the fourth lens has a positive refractive power, the fifth lens has a negative refractive power, the sixth lens has a positive refractive power, the seventh lens has a positive refractive power, and the eighth lens has a negative refractive power.

The present invention further discloses an optical lens assembly, which includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element. The first lens has negative diopter and comprises an object side surface and an image side surface, the radius of curvature of the object side surface is R1, the radius of curvature of the image side surface is R2, and | R1/R2| ≧ 1. The second lens has a refractive power, the third lens has a positive refractive power, the fourth lens has a positive refractive power, the fifth lens has a negative refractive power, the sixth lens has a positive refractive power, the seventh lens has a positive refractive power, and the eighth lens has a negative refractive power.

The present invention further discloses an optical lens assembly, which includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element. The first lens has negative diopter, the second lens has diopter, the third lens has positive diopter, the fourth lens has positive diopter, the fifth lens has negative diopter, the sixth lens has positive diopter and the seventh lens has positive diopter. In addition, the eighth lens element includes an image-side surface having an inflection point, an effective radius of the image-side surface being r, the image-side surface having an intersection point at an optical axis, the inflection point being at a distance H from the optical axis, the inflection point being mapped to a mapped position on the optical axis, the mapped position being at a distance d from the intersection point, and | r/d | ≦ 30 and/or | r/H | ≦ 2.

In some embodiments, the first lens, the second lens and the third lens have a positive refractive power as a whole, and/or the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens have a positive refractive power as a whole.

In some embodiments, the first lens is a glass lens, and/or at least one of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens is a plastic lens or a glass lens.

In some embodiments, the optical lens satisfies at least one of the following conditions: the first lens element is a convex-concave lens, the second lens element is a concave lens element, the third lens element is a biconvex lens element, the fourth lens element is a biconvex lens element, the fifth lens element is a biconcave lens element, the sixth lens element is a biconvex lens element, the seventh lens element is a biconvex lens element, and the eighth lens element is a convex-concave lens element or a biconcave lens element.

In some embodiments, the first lens is a spherical lens, and/or at least one of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens is an aspheric lens or a free-form lens.

In some embodiments, the optical lens has a focal length of F, a total lens length of TTL, an image height of Y, an aperture value of FNO, and a field of view of FOV, and at least one of the following conditions is satisfied: F/TTL is less than or equal to 0.5, F/Y is less than or equal to 1, FNO TTL (percent F)/FOV Y (percent FOV)/Y (percent F) is less than or equal to 0, and FNO TTL (percent F)/FOV Y (percent FOV)/Y (percent FOV) is less than or equal to 0.3.

In some embodiments, the optical lens has a focal length F, and the image-side surface of the third lens element is separated from the object-side surface of the fourth lens element by a distance D, wherein | F/D | is greater than or equal to 1.

In some embodiments, the first lens has a refractive index N1, an abbe number V1, the second lens has a refractive index N2, an abbe number V2, the third lens has a refractive index N3, an abbe number V3, the fourth lens has a refractive index N4, an abbe number V4, the fifth lens has a refractive index N5, an abbe number V5, the sixth lens has a refractive index N6, an abbe number V6, the seventh lens has a refractive index N7, an abbe number V7, the eighth lens has a refractive index N8, an abbe number V8, and the optical lens satisfies at least one of the following conditions: n1 is not less than N2, N1 is not less than N4, N1 is not less than N5, N1 is not less than N6, N1 is not less than N7, N1 is not less than N8, N3 is not less than N2, V2 is not less than V1, V2 is not less than V3, V4 is not less than V1, V6 is not less than V1, V7 is not less than V1, V3 is not less than V5 and V3 is not less than V8.

In summary, the optical lens of the present invention has the features of low distortion, large aperture, large field of view, small volume and low cost.

Drawings

FIG. 1 is a cross-sectional view of an optical lens according to an embodiment of the present invention;

FIG. 2 is a diagram illustrating an embodiment of lens parameters of the optical lens system shown in FIG. 1;

FIG. 3 is a diagram of aspheric coefficients of an aspheric lens of an embodiment of the optical lens of FIG. 1;

fig. 4 is an enlarged view of the eighth lens in fig. 1.

Detailed Description

In the following description, for purposes of explanation, numerous implementation details are set forth in order to provide a thorough understanding of the various embodiments of the present invention. It should be understood, however, that these implementation details are not to be interpreted as limiting the invention. That is, in some embodiments of the invention, such implementation details are not necessary. In addition, for the sake of simplicity, some conventional structures and elements are shown in the drawings in a simple schematic manner. Also, unless otherwise indicated, like reference numerals may be used to identify corresponding elements in different figures. The drawings are for clarity of understanding, and do not show actual dimensions of the elements.

Fig. 1 is a cross-sectional view of an optical lens 100 according to an embodiment of the invention. Only the optical structure inside the optical lens 100 is shown, and the rest of the structure can be designed by those skilled in the art and will be omitted here. The optical lens 100 has the characteristics of low distortion, large aperture, large viewing angle, small volume and low cost, and can be applied to various devices with image projection or image capture functions, such as: handheld communication systems, aerial cameras, motion cameras, vehicular cameras, surveillance systems, digital cameras, digital video cameras or projectors, and the like.

In fig. 1, the left side is an object side (object side), the right side is an image side (image side), and the light beam passes through each lens element of the optical lens assembly 100 from the object side and is imaged on an imaging plane IMA at the image side. In the present embodiment, the optical lens 100 includes, in order from an object side to an image side, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, a seventh lens element L7 and an eighth lens element L8, which are arranged along an optical axis a. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 may have diopters, respectively.

In an embodiment, the optical lens 100 has a first lens group G1 and a second lens group G2, and the first lens group G1 and the second lens group G2 can have diopter respectively. The first lens group G1 may include a first lens L1, a second lens L2 and a third lens L3, and the second lens group G2 may include a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7 and an eighth lens L8.

In one embodiment, the first total refractive power of the first lens element L1, the second lens element L2 and the third lens element L3 is positive, and the second total refractive power of the fourth lens element L4, the fifth lens element L5, the sixth lens element L6, the seventh lens element L7 and the eighth lens element L8 is positive; that is, the first lens group G1 and the second lens group G2 may both have positive refractive power. In another embodiment, the diopter of the first lens group G1 is greater than that of the second lens group G2, that is, the first lens group G1 has better light-receiving capability. Since the first lens group G1 is closer to the object side, the field of view (FOV) of the optical lens 100 is mainly determined by the first lens group G1.

In one embodiment, any four of the eight lenses of the optical lens 100 may have positive refractive power, and the other four lenses may have negative refractive power; in another embodiment, the first lens L1 and the fifth lens L5 may have negative refractive power, the second lens L2, the seventh lens L7 and the eighth lens L8 may each have positive refractive power or negative refractive power, and the third lens L3, the fourth lens L4 and the sixth lens L6 may have positive refractive power; in still another embodiment, the second lens L2 may have a negative refractive power, the seventh lens L7 has a positive refractive power, and/or the eighth lens L8 may have a negative refractive power.

In one embodiment, when the radius of curvature of the object-side surface S1 and the radius of curvature of the image-side surface S2 of the first lens element L1 are R1 and R2, respectively, the first lens element L1 satisfies the condition of 1 ≦ R1/R2 |.

In one embodiment, the focal length of the optical lens 100 is F, and the optical lens 100 satisfies the condition of 1 ≦ F/D ≦. Where D may be a distance between the first lens group G1 and the second lens group G2, or a distance between the image-side surface S6 of the third lens L3 and the object-side surface S7 of the fourth lens L4. In one embodiment, D is a distance between the image-side surface S6 and the object-side surface S7 on the optical axis a.

In an embodiment, if the Total Track Length (TTL) of the optical lens 100 is TTL, F/TTL is less than or equal to 0.5. The total lens length may be defined as the distance between the object-side surface S1 of the first lens element L1 and the image plane IMA.

In one embodiment, the optical lens 100 can converge an incident light beam from an object side onto an image plane IMA on an image side, and if an image height of an object on the image plane IMA is Y, F/Y is less than or equal to 1.5.

In one embodiment, the field of view of the optical lens 100 is the FOV, and the optical lens 100 further includes an aperture STO. If the aperture value of the aperture STO is FNO, 0 is equal to or less than (FNO × TTL)/(FOV × Y) and/or (FNO × TTL)/(FOV × Y) is equal to or less than 0.3.

Furthermore, in an embodiment, the first lens L has a refractive index N and an abbe number V, the second lens L has a refractive index N and an abbe number V, the third lens L has a refractive index N and an abbe number V, the fourth lens L has a refractive index N and an abbe number V, the fifth lens L has a refractive index N and an abbe number V, the sixth lens L has a refractive index N and an abbe number V, the seventh lens L has a refractive index N and an abbe number V, the eighth lens L has a refractive index N and an abbe number V, and the optical lens 100 satisfies at least one condition of N ≥ N, N ≥ N, V ≥ V, V ≥ V, and V ≥ V.

In one embodiment, the optical lens 100 satisfies at least one of conditions of N1-N2 ≥ 0.05, N1-N4 ≥ 0.05, N1-N5 ≥ 0.05, N1-N6 ≥ 0.05, N1-N7 ≥ 0.05, N1-N8 ≥ 0.05, N3-N2 ≥ 0.05, V2-V1 ≥ 5, V2-V3 ≥ 5, V4-V1 ≥ 5, V6-V1 ≥ 5, V7-V1 ≥ 5, V3-V5 ≥ 5, and V3-V8 ≥ 5.

In addition, in an embodiment, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 may be a glass lens made of a glass material or a plastic lens made of a plastic material, respectively. The material of the plastic lens may include, but is not limited to, polycarbonate (polycarbonate), cyclic olefin copolymer (e.g., APEL), polyester resin (e.g., OKP4 or OKP4HT), and the like, or may be a mixture and/or compound material including at least one of the foregoing. Specifically, in one embodiment, the first lens L1 and/or the third lens L3 are glass lenses; in another embodiment, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 are plastic lenses or glass lenses, respectively.

In addition, in an embodiment, at least two of the second lens L2, the fourth lens L4, the sixth lens L6 and the seventh lens L7 may be made of the same material, or made of materials having the same refractive index and/or the same abbe number; in another embodiment, the fifth lens L5 and the eighth lens L8 can be made of the same material, or made of materials with the same refractive index and/or the same abbe number. In another embodiment, at least two of the second lens L2, the fourth lens L4, the sixth lens L6 and the seventh lens L7 have the same refractive index and/or abbe number, and/or the fifth lens L5 and the eighth lens L8 have the same refractive index and/or abbe number.

In addition, in an embodiment, the first lens element L1, the second lens element L2, the third lens element L3, the fourth lens element L4, the fifth lens element L5, the sixth lens element L6, the seventh lens element L7 and the eighth lens element L8 may be a spherical lens element, a free-form lens element or an aspheric lens element, respectively. In one embodiment, at least one of the second lens element L2, the fourth lens element L4, the fifth lens element L5, the sixth lens element L6, the seventh lens element L7 and the eighth lens element L8 is an aspheric lens element or a free-form lens element. In one embodiment, the second lens element L2, the fourth lens element L4, the fifth lens element L5, the sixth lens element L6, the seventh lens element L7 and the eighth lens element L8 are aspheric lens elements.

Specifically, each free-form surface lens has at least one free-form surface, i.e., the object-side surface and/or the image-side surface of the free-form surface lens is a free-form surface; each aspheric lens has at least one aspheric surface, i.e., the object-side surface and/or the image-side surface of the aspheric lens are aspheric surfaces. And each aspheric surface can satisfy the following mathematical formula:

where Z is a coordinate value in the optical axis OA direction, the light transmission direction is the positive direction, a4, a6, A8, a10, a12, a14, and a16 are aspheric coefficients, K is a conic constant, C is 1/R, R is a curvature radius, Y is a coordinate value orthogonal to the optical axis OA direction, and the direction away from the optical axis OA is the positive direction. In addition, the values of the parameters or coefficients of the mathematical expression of each aspheric surface can be set respectively to determine the focal length of each position point of the aspheric surface.

Fig. 2 shows an embodiment of each lens parameter of the optical lens 100 of fig. 1, which includes a curvature radius, a thickness, a refractive index, an abbe number (abbe number), and the like of each lens. The surface numbers of the lenses are arranged in order from the object side to the image side, for example: "St" represents the stop St, "S1" represents the object-side surface S1 OF the first lens L1, "S2" represents the image-side surface S2 … OF the first lens L1, "S17" and "S18" represent the object-side surface S17 and the image-side surface S18, respectively, OF the optical sheet OF, and so on. In addition, "thickness" represents a distance between the surface and a surface adjacent to the image side, for example, the "thickness" of the object side surface S1 is a distance between the object side surface S1 and the image side surface S2; the "thickness" of the image-side surface S2 is the distance between the image-side surface S2 and the object-side surface S3 of the second lens L2.

Fig. 3 shows aspheric coefficients of an aspheric lens of an embodiment of the optical lens 100 of fig. 1. If the object-side surfaces S3, S7, S9, S11, S13, S15 and the image-side surfaces S4, S8, S10, S12, S14, S16 are aspheric surfaces, coefficients of the respective aspheric surface equations may be as shown in fig. 3.

Referring to fig. 1 to 3, the object-side surface S1 and the image-side surface S2 of the first lens element L1 may both have positive refractive index. The object-side surface S1 may be a convex surface convex toward the object side, and the image-side surface S2 may be a concave surface concave toward the object side. Further, the first lens L1 may employ a lens having a negative refractive power, including but not limited to a convex-concave lens having a negative refractive power, a glass or plastic lens, and any one or combination of a spherical or aspherical lens. In addition, the first object-side surface S1 protruding toward the object side can make the first lens L1 have a larger light-collecting angle, and in the embodiment, the width of the field of view FOV of the optical lens 100 reaches about 200 degrees to 220 degrees. On the other hand, the first lens L1 may have a larger effective diameter Φ 1, so that the light receiving amount of the optical lens 100 is increased, in this embodiment, the effective diameter Φ 1 is greater than or equal to 8 centimeters (cm).

The object-side surface S3 and the image-side surface S4 of the second lens element L2 may both have positive refractive index. The object side surface S3 may be convex toward the object side at the optical axis, and the image side surface S4 may be concave toward the object side. Further, the second lens L2 may employ a lens having optical power, including but not limited to a concave lens having negative or positive optical power, a glass or plastic lens, and any one or combination of a spherical or aspherical lens.

The object-side surfaces S5, S7, S11 and S13 of the third lens element L3, the fourth lens element L4, the sixth lens element L6 and the seventh lens element L7 all have positive refractive index, and the image-side surfaces S6, S8, S12 and S14 all have negative refractive index. The object-side surfaces S5, S7, S11, S13 may be convex surfaces protruding toward the object side, and the image-side surfaces S6, S8, S12, S14 may be convex surfaces protruding toward the image side. Further, the third lens L3, the fourth lens L4, the sixth lens L6 and the seventh lens L7 may be any one or a combination of lenses having positive refractive power, including but not limited to a biconvex lens, a glass or plastic lens, and a spherical or aspherical lens having positive refractive power, respectively.

The object-side surface S9 of the fifth lens element L5 can have a negative refractive index, and the image-side surface S10 can have a positive refractive index. The object side surface S9 may be a concave surface that is concave toward the image side, and the image side surface S10 may be a concave surface that is concave toward the object side. Further, the fifth lens L5 may employ a lens having a negative refractive power, including but not limited to a biconcave lens having a negative refractive power, a glass or plastic lens, and any one or combination of a spherical or aspherical lens.

Fig. 4 is an enlarged view of the eighth lens L8 in fig. 1. As shown in the drawing, the object-side surface S15 and the image-side surface S16 of the eighth lens element L8 may both have positive refractive power at the optical axis OA, and the object-side surface S15 may be entirely concave toward the image side and the image-side surface S16 may be entirely concave toward the object side. Further, the eighth lens L8 may employ a lens having refractive power, including but not limited to any one or a combination of a convex-concave or double-concave lens having positive or negative refractive power, a glass or plastic lens, and a spherical or aspherical lens.

In one embodiment, the radius of curvature of the object-side surface S15 of the eighth lens L8 is R15, the radius of curvature of the image-side surface S16 is R16, and | (R15-R16)/(R15+ R16) | ≦ 5.

Further, as shown in fig. 4, the image-side surface S16 of the eighth lens L8 intersects the optical axis a at a point of intersection P1; the image-side surface S16 has a curvature radius gradually changing from positive refractive power to negative refractive power from the center to the direction away from the optical axis, and forms an inflection point P2 on the side surface S16, i.e., the inflection point P2 of the image-side surface S16 is located on the image-side surface S16 closest to the image plane IMA. In one embodiment, if the distance from the inflection point P2 to the optical axis A is H and the effective radius of the image-side surface S16 is r, then | r/H | ≦ 2. Furthermore, in another embodiment, the mapping position P3 is the position where the inflection point P2 is mapped onto the optical axis A, and if the distance between the intersection point P1 and the mapping position P3 is d, then | r/d | ≦ 30.

Thus, the first lens group G1 constituted by the first lens L1, the second lens L2 and the third lens L3 can make the optical lens 100 have a wide field of view FOV; the second lens group G2 formed by the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 can make the optical lens 100 have a low distortion value and a high resolution.

In one embodiment, the optical lens 100 may further include an aperture stop STO and an optical sheet OF, and an image capturing unit (not shown) may be disposed on the image plane IMA for performing photoelectric conversion on an incident light beam passing through the optical lens 100. The stop STO can control the incident light quantity and the relative angle between the incident light and the optical axis a after the incident light passes through the stop STO, so as to effectively shorten the lens size, wherein the stop STO can be disposed between the third lens L3 and the fourth lens L4, but not limited thereto, the stop STO can also be disposed between the object side of the first lens L1, between any two lenses, or between the eighth lens L8 and the image plane IMA; the optical sheet OF may be an infrared filter (IR filter), a transparent protective glass, or other thin film structures capable OF achieving specific optical effects. In another embodiment, the optical sheet OF can be realized by two lenses to achieve substantially the same effect.

In one embodiment, the stop STO is disposed between the first lens group G1 and the second lens group G2, and can control the relative angle between the light passing through the first lens group G1 and the optical axis a. That is, by adjusting the aperture of the stop STO, the size of the image formed on the image plane IMA can be controlled. In addition, since the light beam passing through the stop STO can be limited within a certain range, the effective diameter of the second lens group G2 can be smaller than that of the first lens group G1, and the overall size of the optical lens 100 can be effectively reduced. Moreover, the second lens group G2 adopts more lenses with aspheric surfaces to further improve the aberration problem of the optical lens 100.

In summary, the optical lens proposed in the present disclosure has the features of low distortion, large aperture, large field of view, small volume and low cost.

The present disclosure has been described in terms of exemplary and preferred embodiments, and it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, the invention is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Accordingly, the appended claims are to be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.