CN111367041B

CN111367041B - Optical lens

Info

Publication number: CN111367041B
Application number: CN201811591547.8A
Authority: CN
Inventors: 陈嘉鸿
Original assignee: Ability Enterprise Co Ltd
Current assignee: Ability Enterprise Co Ltd
Priority date: 2018-12-25
Filing date: 2018-12-25
Publication date: 2022-11-01
Anticipated expiration: 2038-12-25
Also published as: CN111367041A

Abstract

An optical lens, in order from an object side to an image side comprising: the optical lens comprises a first lens with diopter, a second lens with diopter, a third lens with positive diopter, a fourth lens with positive diopter and a fifth lens with diopter. The object side surface of the first lens is a concave surface or a plane; the first lens and the second lens generally present negative diopters; the refractive index of the fifth lens element varies in the radial direction from the center point to a position away from the optical axis.

Description

Optical lens

Technical Field

The present invention relates to an optical lens, and more particularly, to an optical lens with a small size and a high imaging quality.

Background

In recent years, as the application of imaging devices has become wider, the demand for compact optical lenses has increased. Moreover, the imaging quality of the optical lens in the market is also more and more demanding. To increase the competitive advantage of the market, miniaturization, high image quality and cost reduction are always the goals that product developers want to pursue.

Therefore, it is desirable to provide a new optical lens, which can achieve the miniaturization of the optical lens and the improvement of the imaging quality of the optical lens on the premise of reducing the manufacturing cost.

Disclosure of Invention

The invention aims to provide an optical lens. On the premise of reducing the manufacturing cost, the miniaturization of the optical lens is realized and the imaging quality of the optical lens is improved.

The invention provides an optical lens. The optical lens includes, in order from an object side to an image side: the optical lens comprises a first lens with diopter, a second lens with diopter, a third lens with positive diopter, a fourth lens with positive diopter and a fifth lens with negative diopter. The object side surface of the first lens element is a concave surface or a flat surface. The first lens and the second lens collectively exhibit a negative refractive power.

The invention further provides an optical lens. The optical lens has an optical axis, and in order from an object side to an image side comprises: the lens comprises a first lens with negative diopter, a second lens, a third lens with positive diopter, a fourth lens with positive diopter and a fifth lens. The second lens is a convex-concave lens. The fifth lens element has an object-side surface and an image-side surface, and refractive indexes of the fifth lens element have the same trend in radial directions away from the optical axis from a center point of the object-side surface and/or the image-side surface.

The invention further provides an optical lens. The optical lens has an optical axis, and in order from an object side to an image side comprises: the lens comprises a first lens with negative diopter, a second lens with diopter, a third lens with positive diopter, a fourth lens with positive diopter and a fifth lens. The first lens and the second lens collectively exhibit a negative refractive power. The refractive index of the fifth lens element has the same trend along the radial direction from the center point to the position far away from the optical axis on the object-side surface and/or the image-side surface of the fifth lens element.

The invention is described in detail below with reference to the drawings and specific examples, but the invention is not limited thereto.

Drawings

FIG. 1 shows an optical lens according to an embodiment of the present invention;

FIG. 2 shows an optical lens according to another embodiment of the present invention;

FIG. 3A is a diagram illustrating an embodiment of lens parameters of the optical lens assembly of FIG. 1 according to the present invention;

FIG. 3B is a chart showing aspheric coefficients of an aspheric lens of the optical lens of FIG. 1 according to one embodiment of the present invention;

FIG. 4A is a diagram illustrating an embodiment of lens parameters of the optical lens assembly of FIG. 2 according to the present invention;

FIG. 4B is a chart of aspheric coefficients for the aspheric lens of the optical lens assembly of FIG. 2 according to one embodiment of the present invention;

FIG. 5 is a schematic diagram illustrating exemplary embodiments of the optical lens of FIGS. 3A and 4A according to the present invention.

Detailed Description

The following detailed description of the various embodiments of the invention, taken in conjunction with the accompanying drawings, is provided by way of illustration. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways, all without departing from the scope of the invention. In the description of the specification, numerous specific details are set forth in order to provide a more thorough understanding of the invention; however, the present invention may be practiced without some or all of these specific details. In other instances, well-known steps or elements have not been described in detail so as not to unnecessarily obscure the present invention. The same or similar elements in the drawings will be denoted by the same or similar symbols. It is specifically noted that the drawings are merely schematic and do not represent actual dimensions or quantities of elements unless specifically stated.

Fig. 1 shows an optical lens OL1 according to an embodiment of the invention, and fig. 2 shows an optical lens OL2 according to another embodiment of the invention. Only the structures related to the embodiments of the present invention are shown to reveal the features of the embodiments, and the rest of the structures are omitted. The optical lenses OL1 and OL2 can be applied to a device with image projecting or capturing functions, including but not limited to a handheld computer system, a handheld communication system, a blank camera, a motion camera, a vehicle camera, a surveillance system, a digital camera, a digital video camera, or a projector.

Referring to fig. 1 and 2, the optical lenses OL1 and OL2 may include, in order from an object side (object side) to an image-forming side (image-forming side), a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4 and a fifth lens element L5. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 may be arranged along an optical axis OA.

In some embodiments, the first lens L1 and the second lens L2 may exhibit negative refractive power as a whole; in other embodiments, the third lens L3, the fourth lens L4 and the fifth lens L5 may exhibit positive refractive power as a whole. The first lens L1 and the second lens L2 can be defined as a first lens group, and the third lens L3, the fourth lens L4 and the fifth lens L5 can be defined as a second lens group, but not limited to the invention.

In some embodiments, the first lens L1 and the second lens L2 may respectively have a diopter, such as a negative diopter or a positive diopter, respectively; the third lens L3 may have a positive refractive power; the fourth lens L4 may have a positive refractive power; the fifth lens L5 may have diopter, for example, positive diopter or negative diopter.

In some embodiments, the first lens L1 has a negative refractive power; in other embodiments, the second lens element L2 and the fifth lens element L5 both have negative refractive power; in another embodiment, the second lens L2 has a positive refractive power, and the fifth lens L5 has a negative refractive power.

In some embodiments, the distance from the object-side surface S1 of the first lens L1 to the imaging plane I is TTL, the focal length (focal length) of the optical lenses OL1 and OL2 is f, and the optical lenses OL1 and OL2 may satisfy at least one of the following conditions: TTL/f is not less than 2, TTL/f is not less than 2.5, TTL/f is not less than 2.8, TTL/f is not less than 3.33, TTL/f is not more than 3.5 and TTL/f is not more than 4.

In some embodiments, the imaging height (half image sensor height) of the optical lenses OL1, OL2 is Y', and the optical lenses OL1, OL2 may satisfy at least one of the following conditions: f/Y 'is not less than 0.5, f/Y' is not less than 0.7, f/Y 'is not less than 0.91, f/Y' is not less than 1.09, f/Y 'is not less than 1.3 and f/Y' is not less than 1.5.

In some embodiments, the optical lenses OL1, OL2 have a view angle of FOV, and the optical lenses OL1, OL2 may satisfy at least one of the following conditions: FOV is more than or equal to 90 degrees, FOV is more than or equal to 100 degrees, FOV is less than or equal to 150 degrees, FOV is less than or equal to 175 degrees and FOV is less than or equal to 180 degrees.

In some embodiments, the aperture value of the optical lenses OL1, OL2 is Fno, and the optical lenses OL1, OL2 can satisfy at least one of the following conditions: (Fno x TTL)/(FOV x Y ') is more than 0, 0.03 is less than or equal to (Fno x TTL)/(FOV x Y '), 0.04 is less than or equal to (Fno x TTL)/(FOV x Y '), (Fno x TTL)/(FOV x Y ') is less than or equal to 0.06, (Fno x TTL)/(FOV x Y ') is less than or equal to 0.1, (Fno x TTL)/(FOV x Y ') is less than or equal to 0.2, and (Fno x TTL)/(FOV x Y ') is less than or equal to 0.3.

In some embodiments, a radius of curvature of the object-side surface S7 of the fourth lens element L4 is R7, a radius of curvature of the image-side surface S8 is R8, and the optical lenses OL1 and OL2 can satisfy at least one of the following conditions: 1 ≦ (R7-R8)/(R7 + R8), 1.4 ≦ (R7-R8)/(R7 + R8), | (R7-R8)/(R7 + R8) ≦ 1.65, and | (R7-R8)/(R7 + R8) ≦ 2.

Further, in some embodiments, the optical lenses OL1, OL2 may also satisfy at least one of the following conditions: more than or equal to 1 (R7-R8)/(R7 + R8), more than or equal to 1.4 (R7-R8)/(R7 + R8), (R7-R8)/(R7 + R8) more than or equal to 1.65 and more than or equal to 2 (R7-R8)/(R7 + R8).

In some embodiments, a radius of curvature of the object-side surface S9 of the fifth lens element L5 is R9, a radius of curvature of the image-side surface S10 is R10, and the optical lenses OL1 and OL2 can satisfy at least one of the following conditions: (R9-R10)/(R9 + R10) 0.1. Ltoreq. (R9-R10)/(R9 + R10) 0.14. Ltoreq. (R9-R10)/(R9 + R10) 0.2, | (R9-R10)/(R9 + R10) 0.6 and | (R9-R10)/(R9 + R10) 1.

Further, in some embodiments, the optical lenses OL1, OL2 may also satisfy at least one of the following conditions: -1 is not more than (R9-R10)/(R9 + R10), -0.6 is not more than (R9-R10)/(R9 + R10), -0.2 is not more than (R9-R10)/(R9 + R10), (R9-R10)/(R9 + R10) is not more than-0.14, (R9-R10)/(R9 + R10) is not more than-0.1 and (R9-R10)/(R9 + R10) is not more than 0.

In some embodiments, the first lens L1 has a refractive index N1 and an abbe number V1, the second lens L2 has a refractive index N2 and an abbe number V2, the third lens L3 has a refractive index N3 and an abbe number V3, the fourth lens L4 has a refractive index N4 and an abbe number V4, the fifth lens L5 has a refractive index N5 and an abbe number V5, and the optical lenses OL1, OL2 may satisfy at least one of the following conditions: n3> N1, N1> N2, N1> N4, N1> N5, V1> V3, V2> V3, V4> V3, and V5> V3.

Further, in some embodiments, the optical lenses OL1, OL2 may satisfy at least one of the following conditions: N3-N1 is more than or equal to 0.05, N1-N2 is more than or equal to 0.05, N1-N4 is more than or equal to 0.05, N1-N5 is more than or equal to 0.05, V1-V3 is more than or equal to 5, V2-V3 is more than or equal to 5, V4-V3 is more than or equal to 5, and V5-V3 is more than or equal to 5.

Furthermore, in some embodiments, the optical lenses OL1, OL2 may satisfy at least one of the following conditions: n2= N4, N2= N5, N4= N5, V2= V4, V2= V5, and V4= V5.

In some embodiments, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 may be a spherical lens, a free-form lens, or an aspheric lens, respectively.

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 a positive direction, A4, A6, A8, a10, and a12 are aspheric coefficients, K is a conic constant, C =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 a 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.

In one embodiment, at least one of the first lens element L1 and the third lens element L3 may be a spherical lens element; in another embodiment, at least one of the second lens L2, the fourth lens L4, and the fifth lens L5 may be an aspheric lens. In an embodiment, the first lens element L1 and the third lens element L3 are all spherical lens elements, and the second lens element L2, the fourth lens element L4 and the fifth lens element L5 are all aspheric lens elements.

In some embodiments, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 may be a glass lens made of a glass material or a plastic lens made of a plastic material. 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 OKP4 HT), and the like, or may be a mixed and/or compounded material including at least one of the foregoing materials.

For example, in some embodiments, at least one of the first lens L1 and the third lens L3 may be a glass lens; in other embodiments, at least one of the second lens L2, the fourth lens L4 and the fifth lens L5 may be a plastic lens. In one embodiment, the first lens element L1 and the third lens element L3 are glass lens elements, and the second lens element L2, the fourth lens element L4 and the fifth lens element L5 are plastic lens elements. Furthermore, in some embodiments, the second lens element L2, the fourth lens element L4 and the fifth lens element L5 are made of the same material.

In some embodiments, referring to fig. 1 and fig. 2, the object-side surface S1 of the first lens element L1 may be a plane or a concave surface concave toward the image side, and has an infinite refractive index or a negative refractive index; the image-side surface S2 of the first lens element L1 may be a concave surface concave toward the object side, and has a positive refractive index. The first lens L1 may employ a lens having a negative refractive power, including but not limited to a biconcave or plano-concave lens having a negative refractive power, a glass lens or a plastic lens, and any one of or a combination of a spherical lens or an aspherical lens.

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

Further, in some embodiments, at least one of the object-side surface S3 and the image-side surface S4 of the second lens element L2 may be an aspheric surface without an inflection point. Specifically, the refractive index has the same trend along the radial direction from the central point of the object-side surface S3 to the distance from the optical axis OA. That is, tangents to any two points of the object-side surface S3 from the center point along the first direction X may both be positive slopes, and tangents from the center point against any two points of the first direction X (i.e., along the-X direction) may both be negative slopes; and/or, similarly, the refractive index on the image-side surface S4 has the same trend along the radial direction from the central point to the optical axis OA. That is, the slopes of tangents at any two points along the first direction X from the center point of the image-side surface S4 may both be positive slopes, and tangents at any two points along the first direction X (i.e., along the-X direction) from the center point may both be negative slopes.

The object-side surface S5 of the third lens element L3 may be planar or concave towards the image side, and has an infinite refractive index or a negative refractive index; the image-side surface S6 may be a convex surface convex toward the image side, which has a negative refractive index. The third lens L3 may employ a lens having a positive refractive power, including but not limited to a meniscus lens or a plano-concave lens having a positive refractive power, a glass lens or a plastic lens, and any one of or a combination of a spherical lens or an aspherical lens.

The object-side surface S7 of the fourth lens element L4 may be a convex surface protruding towards the object side and having a positive refractive index; the image-side surface S8 may be a convex surface convex toward the image side, which has a negative refractive index. The fourth lens L4 may employ a lens having a positive refractive power, including but not limited to a biconvex lens, a glass lens or a plastic lens having a positive refractive power, and any one of or a combination of a spherical lens or an aspherical lens.

The object-side surface S9 of the fifth lens element L5 may be a concave surface concave toward the image side and has a negative refractive index; the image-side surface S10 may be a convex surface convex toward the image side, which has a negative refractive index. The fifth lens L5 may employ a lens having a refractive power, including but not limited to a meniscus lens, a glass lens or a plastic lens having a negative refractive power or a positive refractive power, and any one of or a combination of a spherical lens or an aspherical lens.

Further, in some embodiments, at least one of the object-side surface S9 and the image-side surface S10 of the fifth lens element L5 may be an aspheric surface without an inflection point. Specifically, on the object-side surface S9, the refractive index has the same trend along the radial direction from the central point to the far optical axis OA. That is, the slopes of tangents to any two points of the object-side surface S9 along the first direction X from the center point may both be negative slopes, and the slopes of tangents to any two points along the first direction X (i.e., along the-X direction) from the center point may both be positive slopes; and/or, similarly, the refractive index on the image-side surface S10 has the same trend along the radial direction from the central point to the optical axis OA. That is, the slopes of tangents from the center point of the image-side surface S4 along any two points in the first direction X may both be negative slopes, and tangents from the center point against any two points in the first direction X (i.e., along the-X direction) may both be positive slopes.

In some embodiments, the optical lenses OL1, OL2 further may include an aperture St; in other embodiments, an image capturing unit (not shown) may be further disposed on the image plane I, and may perform photoelectric conversion on the light beams passing through the optical lenses OL1 and OL2. The stop St may be disposed on the object side of the first lens L1, may be disposed in any gap between any two of the first lens L1 to the fifth lens L5, or may be disposed between the fifth lens L5 and the image plane I. In one embodiment, the stop St is disposed between the first lens L1 and the second lens L2; in another embodiment, the stop St is disposed between the second lens L2 and the third lens L3, but not limited thereto.

Furthermore, the optical lenses OL1, OL2 may further include an optical filter Ft and/or a protective sheet C. In some embodiments, the filter Ft may be disposed between the fifth lens L5 and the image plane I. In some embodiments, the Filter Ft may be an infrared Filter (IR Filter); in other embodiments, the protection sheet C may be disposed between the filter Ft and the image plane I, and a filter (not shown) may be further formed on the protection sheet C; in still other embodiments, only the protection sheet C having the functions of protecting the image capturing unit and filtering the infrared beam may be used.

Fig. 3A shows an embodiment of the lens parameters of the optical lens OL1 of fig. 1 according to the present invention, which includes the curvature radius, thickness, refractive index, 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 \8230ofthe first lens L1, "S11" and "S12" represent the object-side surface S11 and the image-side surface S12 of the filter Ft, respectively, "S13" and "S14" represent the object-side surface S13 and the image-side surface S14 of the protective sheet C, respectively, and so on. In addition, "thickness" represents a distance between the surface and a surface adjacent to the image side, for example, "thickness" of the object-side surface S1 is a distance between the object-side surface S1 of the first lens element L1 and the image-side surface S2 of the first lens element L1; the "thickness" of the image-side surface S2 is a distance between the image-side surface S2 of the first lens element L1 and the object-side surface S3 of the second lens element L2.

Fig. 3B shows aspheric coefficients of an aspheric lens of an embodiment of the optical lens OL1 of fig. 1 according to the invention. If the object-side surfaces S3, S7, S9 and the image-side surfaces S4, S8, S10 of the second lens element L2, the fourth lens element L4 and the fifth lens element L5 of the optical lens assembly OL1 are aspheric surfaces, the coefficients of the aspheric surface equations can be as shown in fig. 3B.

Fig. 4A illustrates an embodiment of the lens parameters of the optical lens OL2 of fig. 2 according to the present invention, which is defined and intended to be substantially the same as fig. 3A.

Fig. 4B shows aspheric coefficients of an aspheric lens of an embodiment of the optical lens OL2 of fig. 2 according to the invention. If the object-side surfaces S3, S7, S9 and the image-side surfaces S4, S8, S10 of the second lens element L2, the fourth lens element L4 and the fifth lens element L5 of the optical lens assembly OL2 are aspheric surfaces, the coefficients of the aspheric surface equations can be as shown in fig. 4B.

Fig. 5 is a flowchart illustrating specific parameters of the optical lenses OL1 and OL2 of fig. 3A and 4A according to the invention, including a focal length f, a distance TTL from the object-side surface S1 of the first lens element L1 to the image plane I, an aperture value Fno, an image height Y', a viewing angle FOV, curvature radii R7 to R10 of the object-side surfaces S7 and S9 and the image-side surfaces S8 and S10, and values of a relationship therebetween.

As can be seen from the above embodiments, the optical lenses OL1 and OL2 can have the characteristics of miniaturization and excellent imaging quality while reducing the manufacturing cost.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

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

the optical lens comprises a first lens with diopter, wherein the object side surface of the first lens is a concave surface or a plane, the distance from the object side surface of the first lens to an imaging surface is TTL, the focal length of the optical lens is f, and TTL/f is less than or equal to 4;

a second lens with diopter, wherein the first lens and the second lens generally present negative diopter;

a third lens having a positive refractive power;

a fourth lens with positive diopter; and

a fifth lens having a negative refractive power.

2. An optical lens having an optical axis, the optical lens comprising five lens elements with diopter, in order from an object side to an image side:

the distance from the object side surface of the first lens to an imaging surface is TTL, the focal length of the optical lens is f, and TTL/f is less than or equal to 4;

a second lens which is a convex-concave lens;

a third lens having a positive refractive power;

a fourth lens having a positive refractive power; and

the fifth lens element has an object-side surface and an image-side surface, and the refractive index of the fifth lens element varies in the same direction from the center of the object-side surface and/or the image-side surface to a radial direction away from the optical axis.

3. An optical lens having an optical axis, the optical lens comprising five lens elements with diopter, in order from an object side to an image side:

the first lens with negative diopter, the distance from the object side surface of the first lens to an imaging surface is TTL, the focal length of the optical lens is f, and TTL/f is less than or equal to 4;

a second lens with diopter, the first lens and the second lens presenting negative diopter as a whole;

a third lens having a positive refractive power;

a fourth lens having a positive refractive power; and

the refractive index of the fifth lens element varies along a radial direction from the central point to a position away from the optical axis.

4. An optical lens according to claim 1, wherein the optical lens further satisfies the condition of 2 ≦ TTL/f.

5. An optical lens according to claim 1, wherein the optical lens has an imaging height Y' and further satisfies at least one of the following conditions: f/Y 'is more than or equal to 0.5 and f/Y' is more than or equal to 1.5.

6. The optical lens of claim 1, wherein the angle of view of the optical lens is FOV, the aperture value is Fno, and the imaging height is Y', and the optical lens further satisfies at least one of the following conditions: FOV is more than or equal to 90 degrees, FOV is less than or equal to 180 degrees, 0 is less than (Fno × TTL)/(FOV × Y ') and (Fno × TTL)/(FOV × Y') is less than or equal to 0.3.

7. An optical lens according to claim 1, wherein a radius of curvature of an object-side surface of the fourth lens element is R7, a radius of curvature of an image-side surface of the fourth lens element is R8, a radius of curvature of an object-side surface of the fifth lens element is R9, a radius of curvature of an image-side surface of the fifth lens element is R10, and at least one of the following conditions is further satisfied: 1 | (R7-R8)/(R7 + R8) |, | (R7-R8)/(R7 + R8) | is less than or equal to 2, | (R9-R10)/(R9 + R10) | is less than or equal to 0 |, and | (R9-R10)/(R9 + R10) | is less than or equal to 1.

8. An optical lens according to claim 1, characterized in that the first lens has a refractive index N1 and an abbe number V1, the second lens has a refractive index N2 and an abbe number V2, the third lens has a refractive index N3 and an abbe number V3, the fourth lens has a refractive index N4 and an abbe number V4, the fifth lens has a refractive index N5 and an abbe number V5, and the optical lens satisfies at least one of the following conditions: n3> N1, N1> N2, N1> N4, N1> N5, V1> V3, V2> V3, V4> V3, and V5> V3.

9. An optical lens according to any one of claims 1 to 3, characterized in that at least one of the following conditions is satisfied: the first lens element is a biconcave lens element or a plano-convex lens element, the third lens element is a meniscus lens element, and the fourth lens element is a biconvex lens element.

10. An optical lens according to any one of claims 2 to 3, characterized in that at least one of the following conditions is satisfied: the slope of a tangent line from the center point of the object-side surface of the second lens element to any two points in a first direction away from the optical axis is a positive slope, and the slope of a tangent line from the center point of the image-side surface of the second lens element to any two points in the first direction away from the optical axis is a positive slope.