CN113406776B

CN113406776B - Lens and method for manufacturing the same

Info

Publication number: CN113406776B
Application number: CN202010507093.2A
Authority: CN
Inventors: 邱伟庭; 曾建雄
Original assignee: Young Optics Inc
Current assignee: Young Optics Inc
Priority date: 2020-03-16
Filing date: 2020-06-05
Publication date: 2024-08-23
Anticipated expiration: 2040-06-05
Also published as: CN113406776A; TW202136844A; TWI828879B

Abstract

A lens includes a first lens group, an aperture and a second lens group which are sequentially arranged along an optical axis from an enlarging side to a reducing side. The first lens group is of negative diopter and comprises three lenses with diopter. The first lens group includes a lens with positive diopter and includes an aspherical lens. The second lens group is positive diopter and comprises three lenses with diopter. The second lens group includes one lens with negative diopter, the lens closest to the reduction side is a combined lens, and includes one aspherical lens. The total number of lenses with diopters is between 6 and 8. The invention also provides a lens manufacturing method.

Description

Lens and method for manufacturing the same

Technical Field

The present invention relates to a lens assembly and a method for manufacturing the same, and more particularly to an image capturing lens assembly and a method for manufacturing the same.

Background

The traditional wide-angle lens is difficult to shrink due to the limitation of the shape and the material of the lens, and is difficult to have imaging quality under wide view angle and large aperture. Therefore, it is necessary to develop a wide viewing angle, high imaging quality, environmental variation resistance, miniaturization, and small thermal drift.

Disclosure of Invention

The invention provides a lens and a manufacturing method thereof, which can effectively reduce the number of lenses, improve aberration, effectively reduce cost and have good optical effect.

The invention provides a lens, which comprises a first lens group, an aperture and a second lens group which are sequentially arranged along an optical axis from an amplifying side to a reducing side. The first lens group is of negative diopter and comprises three lenses with diopter. The first lens group includes a lens with positive diopter and includes an aspherical lens. The second lens group is positive diopter and comprises three lenses with diopter. The second lens group includes one lens with negative diopter, the lens closest to the reduction side is a combined lens, and includes one aspherical lens. The total number of lenses with diopters is between 6 and 8. The lens satisfies 9< LT/EFL <15 and LT/D1<12, where LT is a distance along the optical axis from a lens surface of the first lens group closest to the magnification side to a lens surface of the second lens group farthest from the first lens group, EFL is an effective focal length of the lens, and D1 is a thickness along the optical axis of a lens of the first lens group closest to the magnification side.

The invention further provides a lens comprising a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged along an optical axis from an amplifying side to a reducing side. Wherein, the fifth lens and the sixth lens are cemented lenses. The lens satisfies 9< LT/EFL <15, 4< D6/D5<10, 180< FOV <230, and 80> A2>50, where LT is the distance on the optical axis from the lens surface of the first lens group closest to the magnification side to the lens surface of the second lens group farthest from the first lens group, EFL is the effective focal length of the lens, D5 is the thickness of the fifth lens on the optical axis, D6 is the thickness of the sixth lens on the optical axis, FOV is the angle of view of the lens, and A2 is the angle between the extension line of the concave edge of the second lens and the optical axis.

The invention also provides a lens manufacturing method, which comprises providing a lens barrel, and arranging and fixing a first lens group, a second lens group and an aperture in the lens barrel. The first lens group is of negative diopter and comprises three lenses with diopter. The first lens group includes a lens with positive diopter and includes an aspherical lens. The second lens group is positive diopter and comprises three lenses with diopter. The second lens group includes one lens with negative diopter, the lens closest to the reduction side is a combined lens, and includes one aspherical lens. The total number of lenses with diopters is between 6 and 8. The lens satisfies 9< LT/EFL <15 and LT/D1<12, where LT is a distance along the optical axis from a lens surface of the first lens group closest to the magnification side to a lens surface of the second lens group farthest from the first lens group, EFL is an effective focal length of the lens, and D1 is a thickness along the optical axis of a lens of the first lens group closest to the magnification side.

Based on the above, in the lens and the manufacturing method thereof of the present invention, the analysis performance is improved by using a plurality of aspherical lenses, and the wide-angle light receiving capability is achieved by using the negative diopter lens, so that the lens has the advantages of effectively reducing the number of lenses, improving the aberration, effectively reducing the cost, and having good optical effects.

The foregoing description is only an overview of the present invention, and is intended to be implemented in accordance with the teachings of the present invention, as well as the preferred embodiments thereof, together with the following detailed description of the invention, given by way of illustration only, together with the accompanying drawings.

Drawings

Fig. 1 is a schematic view of a lens barrel according to an embodiment of the invention.

Fig. 2A and 2B are respectively an astigmatic field diagram and a distortion diagram of the lens barrel of the embodiment of fig. 1.

Fig. 3 is a schematic view of a lens barrel according to another embodiment of the invention.

Fig. 4A and 4B are respectively an astigmatic field diagram and a distortion diagram of the lens barrel of the embodiment of fig. 3.

Fig. 5 is a schematic view of a lens barrel according to another embodiment of the invention.

Fig. 6A and 6B are respectively an astigmatic field plot and a distortion plot of the lens barrel of the embodiment of fig. 5.

Detailed Description

Fig. 1 is a schematic view of a lens barrel according to an embodiment of the invention. Please refer to fig. 1. The present embodiment provides a lens 100, which is an imaging lens, and is applicable to fields of security monitoring, vehicle-mounted or mobile photography, but the present invention is not limited thereto. Specifically, the lens 100 is, for example, a fisheye lens, and uses a plurality of aspherical lenses to improve the resolution, and a negative diopter lens is used to achieve wide-angle light receiving capability.

The lens 100 has an optical axis a, and includes a first lens assembly 130, an aperture 140 and a second lens assembly 150 sequentially arranged from an enlarging side 110 to a reducing side 120, wherein the enlarging side 110 is a side of the light input lens 100, and the reducing side 120 is a side of the light output lens 100. In the present embodiment, the lens 100 further includes an infrared filter 160 and a transparent protective cover 170, and the light entering the lens 100 can be transmitted from the magnifying side 110 toward the shrinking side 120 and imaged onto the imaging surface 180.

The first lens group 130 has negative diopter and includes at least one aspherical lens. The first lens assembly 130 comprises a first lens L1, a second lens L2 and a third lens L3, which are sequentially arranged from the magnifying side 110 to the de-magnifying side 120.

The second lens group 150 has positive refractive power and includes at least one aspherical lens. In the present embodiment, the second lens assembly 150 includes a fourth lens L4, a fifth lens L5 and a sixth lens L6 sequentially arranged from the magnification side 110 to the reduction side 120. Wherein one of the fifth lens L5 and the sixth lens L6 has a positive refractive power and the other has a negative refractive power. In the present embodiment, the diopter of the fifth lens L5 is negative, and the diopter of the sixth lens L6 is positive. However, in an embodiment, the diopter of the fifth lens L5 may be positive and the diopter of the sixth lens L6 may be negative, and the present invention is not limited thereto. In the present embodiment, at least two lenses (i.e., the fifth lens L5 and the sixth lens L6) closest to the reduction side 120 in the second lens group 150 are cemented lenses.

Specifically, in the present embodiment, the total lens number of the lens 100 is 6, the number of aspherical lenses is 4, and the number of cemented lenses is 1, so that the number of lenses can be effectively reduced and aberration can be improved. In addition, in the present embodiment, the diopters of the 6 lenses in the lens 100 are sequentially negative, positive, negative, and positive from the magnification side 110 to the reduction side 120, and the materials are glass, plastic, glass, plastic, and plastic, respectively. In other words, the materials of the second lens L2, the third lens L3, the fifth lens L5 and the sixth lens L6 are plastic. Therefore, the cost can be effectively reduced, but the present invention is not limited thereto.

The number of lenses with diopters in the lens 100 of the present embodiment is between 6 and 8, which is most cost effective and preferred. Also, the lens 100 of the present embodiment conforms to 9< LT/EFL <15, where LT is the distance along the optical axis a between the lens surface closest to the magnification side 110 in the lens 100 (i.e., the surface S1 of the first lens L1) and the lens surface closest to the reduction side 120 in the lens 100 (i.e., the surface S13 of the sixth lens L6), and EFL is the effective focal length of the lens 100. In the present embodiment, the lens 100 conforms to LT/D1<12, where D1 is the thickness of the lens closest to the magnification side 110 (i.e., the first lens L1) in the lens 100 along the optical axis a. It is worth mentioning that the diopter of an image side surface (i.e. the surface S6) of the third lens element L3 is positive.

On the other hand, in the present embodiment, the lens 100 conforms to 4< Z1/Z2<10, where Z1 is the thickness of the fifth lens L5 or the sixth lens L6 along the optical axis a is larger, and Z2 is the thickness of the fifth lens L5 or the sixth lens L6 along the optical axis a is smaller.

In addition, the lens 100 of the present embodiment conforms to 180 degrees < FOV <230 degrees, where FOV is the maximum field angle of the lens 100. In a preferred embodiment, lens 100 conforms to FOV >210 degrees. The lens closest to the magnification side 110 (i.e., the first lens L1) of the present embodiment has a thickness of greater than 1mm along the optical axis a. The lens 100 of the present embodiment conforms to 0.7< R1/LT <2, where R1 is the effective radius R1 of the lens closest to the magnification side 110 (i.e., the first lens L1) in the lens 100. The lens 100 of the present embodiment conforms to 0.2< RL/LT <0.38, where RL is the effective radius r6 of the lens closest to the reduction side 120 (i.e., the sixth lens L6) in the lens 100. The lens 100 of the present embodiment conforms to D6/D5>2, wherein T6 is the thickness of the sixth lens L6 along the optical axis a, and D5 is the thickness of the fifth lens L5 along the optical axis a. The lens assembly 100 of the present embodiment corresponds to 50< A2<80, wherein A2 is an angle B (or referred to as an opening angle) between a tangential line of a concave edge of the second lens element L2 and a direction perpendicular to the optical axis a, as shown in fig. 1.

Therefore, in the present embodiment, the lens 100 is a fixed-focus image capturing lens, and the aperture of the lens 100 can reach F/2.0, the total length can be within 12.5mm, and the half-view angle can reach more than 105 degrees. More specifically, the lens 100 of the present embodiment is a fisheye lens, which can reduce the number of lenses, improve aberration, reduce cost, and have good optical effects.

In this embodiment, the actual design of each of the foregoing elements can be seen in the following list one.

List one

Please refer to fig. 1 and table one. Specifically, in the lens assembly 100 of the present embodiment, the first lens element L1 has a surface S1 and a surface S2 in sequence from the zooming-in side 110 to the zooming-out side 120, the first lens element L2 has a surface S3 and a surface S4 in sequence from the zooming-in side 110 to the zooming-out side 120, and the surfaces S3 and S4 are aspheric surfaces, i.e. are denoted by the symbol x as aspheric surfaces, and so on, the surfaces corresponding to the elements will not be repeated. In addition, TTL is the total lens length, i.e., the distance between the lens surface closest to the magnification side 110 in the lens 100 (i.e., the surface S1 of the first lens L1) and the imaging plane 180 in the lens 100 along the optical axis a, and IMH is the image plane diameter.

Further, the interval in table one is the distance between the surface from the enlargement side 110 to the next surface of the reduction side 120. In other words, the thickness of the first lens L1 is 10.465 mm, the thickness of the second lens L2 is 6.101 mm, and the distance between the adjacent surfaces of the first lens L1 and the second lens L2 is 2.931 mm, and so on, so the detailed description will not be repeated.

In addition, the radius of curvature in table one is the radius of curvature of the surface, and the positive and negative values thereof represent the bending direction, for example, the radius of curvature of the surface S1 of the first lens L1 is positive, and the radius of curvature of the surface S2 of the first lens L1 is positive. Therefore, the first lens L1 is a convex-concave lens. For example, the radius of curvature of the surface S12 of the sixth lens L6 is positive, and the radius of curvature of the surface S13 of the sixth lens L6 is negative. Therefore, the first lens L1 is a biconvex lens, and so on, so the description thereof will not be repeated.

The second table below lists the quadric coefficient value K for each aspheric surface and the aspheric coefficients A-H for each order. The aspherical polynomial can be expressed by the following formula (1):

Where x is the offset (sag) in the direction of the optical axis a, c' is the inverse of the radius of the sphere of revolution (Osculating Sphere), i.e. the inverse of the radius of curvature near the optical axis, K is the quadric coefficient, and y is the aspherical height, i.e. the height from the center of the lens to the edge of the lens. a-H represent each order aspheric coefficient of the aspheric polynomial, respectively.

Watch II

	S3	S4	S5	S6
					K	-1.924	-0.988	-4.477	-6.852
A	0	0	0	0
					B	9.14E-04	4.92E-02	6.20E-02	7.08E-02
C	-7.76E-03	4.06E-02	4.89E-03	-6.29E-03
					D	2.47E-03	-4.61E-02	-4.27E-03	-1.63E-01
E	-3.72E-04	2.00E-02	5.05E-03	5.67E-01
					F	2.84E-05	1.77E-03	-1.72E-03	-1.01E-02
G	-8.25E-07	1.71E-03	5.58E-04	-1.26E+00
					H	-1.14E-08	-1.43E-03	-3.01E-04	8.52E-01
	S10	S11	S12	S13
					K	1.14	-1.693	-1.693	-6.985
A	0	0	0	0
					B	-3.74E-02	2.48E-02	2.48E-02	-4.59E-02
C	2.49E-02	3.62E-02	3.62E-02	3.02E-02
					D	-8.76E-03	-1.23E-02	-1.23E-02	-1.16E-02
E	-7.24E-06	-3.13E-05	-3.13E-05	2.08E-03
					F	8.48E-06	1.17E-05	1.17E-05	3.62E-05
G	1.35E-04	5.21E-05	5.21E-05	-5.48E-05
					H	1.50E-04	1.06E-04	1.06E-04	4.16E-06

Fig. 3 is a schematic view of a lens barrel according to another embodiment of the invention. Please refer to fig. 3. The lens 100A shown in the present embodiment is similar to the lens 100 shown in fig. 1. The main difference is that in the present embodiment, the surface S11 of the fifth lens L5 is spherical.

In this embodiment, the actual design of each of the foregoing elements can be found in the following table three. The interpretation of Table III is the same as that of Table I, and therefore, it is not repeated.

Watch III

The following Table IV lists the quadric coefficient values K for each aspheric surface and the aspheric coefficients A-H for each order.

Table four

Fig. 5 is a schematic view of a lens barrel according to another embodiment of the invention. Please refer to fig. 5. The lens 100B shown in the present embodiment is similar to the lens 100 shown in fig. 1. The main difference is that the surface S11 of the fifth lens L5 is spherical in this embodiment.

In this embodiment, the actual design of each element described above can be found in the following fifth table. The interpretation of Table five is the same as Table one, and therefore, will not be repeated.

TABLE five

The following Table six lists the quadric coefficient values K for each of the aspheres and the aspherical coefficients A-H for each of the orders.

TABLE six

Fig. 2A and 2B, fig. 4A and 4B, and fig. 6A and 6B are astigmatic field curves and distortion diagrams of the lenses 100, 100A, 100B according to the embodiment, respectively. Fig. 2A, 4A, 6A are astigmatic field curves (ASTIGMATIC FIELD cutvatures) of the lenses 100, 100A, 100B, the horizontal axis of which is expressed as the focal point displacement (mm), the vertical axis is expressed as the image height, T is the curve in the meridian direction, S is the curve in the sagittal direction, and different line segment patterns are the measurement conditions at different wavelengths. Fig. 2B, 4B, 6B are graphs of distortion (distortion) of the lenses 100, 100A, 100B, with the horizontal axis indicated as the percent (%) distortion, the vertical axis indicated as image height, and different line segment patterns representing measurement at different wavelengths. It can be verified that the astigmatic field curvature and distortion of the lenses 100, 100A, 100B of the present embodiment are in the standard range between 450 nm and 650 nm, so that the lenses have good optical imaging quality, as shown in fig. 2A and 2B, fig. 4A and 4B, and fig. 6A and 6B.

In summary, in the lens and the manufacturing method thereof of the present invention, the analysis performance is improved by using a plurality of aspherical lenses, and the wide-angle light receiving capability is achieved by using the negative diopter lens, so that the lens and the manufacturing method thereof can effectively reduce the number of lenses, improve the aberration, effectively reduce the cost, and have good optical effects.

The present invention is not limited to the preferred embodiments, and the present invention is described above in any way, but is not limited to the preferred embodiments, and any person skilled in the art will appreciate that the present invention is not limited to the embodiments described above, while the above-described methods and techniques may be utilized to make some changes or modifications to equivalent embodiments, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical principles of the present invention will still fall within the scope of the technical solutions of the present invention.

Claims

1. A lens, comprising:

a first lens group, an aperture and a second lens group which are sequentially arranged from an amplifying side to a reducing side along an optical axis;

Wherein,

The first lens group is of negative diopter, the first lens group comprises a first lens with diopter, a second lens with diopter and a third lens with diopter, the first lens group comprises a lens with positive diopter, the surface of the lens with positive diopter, which faces the amplifying side, is of a convex surface, and the first lens group comprises an aspheric lens;

The second lens group is positive diopter, the second lens group comprises a fourth lens with diopter, a fifth lens with diopter and a sixth lens with diopter, the second lens group comprises a lens with negative diopter, the lens of the second lens group closest to the shrinking side is a combined lens, and the second lens group comprises an aspheric lens;

the total number of lenses with diopters in the lens is between 6 and 8; and

The lens satisfies the following conditions:

(1) 9< LT/EFL <15, wherein LT is a distance along the optical axis from a lens surface of the first lens group closest to the magnification side to a lens surface of the second lens group farthest from the first lens group, and EFL is an effective focal length of the lens; and

(2) LT/D1<12, wherein D1 is the thickness of the lens closest to the magnification side in the first lens group along the optical axis

(3) 80> A2>50 wherein A2 is the angle between the tangent to the concave edge of the second lens and a direction perpendicular to the optical axis

The diopters of the first lens to the fourth lens are negative, positive and positive in sequence;

one of the fifth lens and the sixth lens has a positive diopter and the other has a negative diopter;

the lens conforms to 4< Z1/Z2<10, where Z1 is the greater of the thickness of the fifth lens or the sixth lens along the optical axis and Z2 is the lesser of the thickness of the fifth lens or the sixth lens along the optical axis.

2. The lens of claim 1 wherein the lens conforms to FOV >210, wherein FOV is the field angle of the lens.

3. The lens barrel of claim 1, wherein a thickness of the lens closest to the magnification side along the optical axis is greater than 1 millimeter.

4. The lens of claim 1, wherein the material of the first lens and the fourth lens is glass, and the material of the second lens, the third lens, the fifth lens and the sixth lens is plastic.

5. A lens, comprising:

A first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an enlarging side to a reducing side along an optical axis;

Wherein,

The surface of the third lens facing the amplifying side is a convex surface;

the fifth lens and the sixth lens are a cemented lens; and

The lens satisfies the following conditions:

(1) 9< LT/EFL <15, wherein LT is a distance along the optical axis from a lens surface of a first lens group closest to the magnification side to a lens surface of a second lens group farthest from the first lens group, and EFL is an effective focal length of the lens;

(2) 4< D6/D5<10, wherein D5 is the thickness of the fifth lens along the optical axis, and D6 is the thickness of the sixth lens along the optical axis;

(3) 180< FOV <230, wherein FOV is the field angle of the lens; and

(4) 80> A2>50, wherein A2 is the angle between the concave edge tangent of the second lens and a direction perpendicular to the optical axis;

One of the fifth lens and the sixth lens has a positive diopter and the other one has a negative diopter.

6. The lens of claim 5 wherein the lens conforms to FOV >210, wherein FOV is the field angle of the lens.

7. The lens barrel of claim 5, wherein a thickness of the lens closest to the magnification side along the optical axis is greater than 1 millimeter.

8. The lens of claim 5, wherein the material of the first lens and the fourth lens is glass, and the material of the second lens, the third lens, the fifth lens and the sixth lens is plastic.