CN108594403A - Optical lens - Google Patents

Abstract

The present invention discloses an optical lens, which comprises, from the object side to the image side, a first lens with negative refractive power, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens with positive refractive power, and a fifth lens with negative refractive power, wherein the thickness of the third lens is greater than 3 mm, the second lens has an Abbe number vd2, 10<vd2<50, and the optical lens satisfies Y'/FL>1.12 and/or TTL/Y'<6.1, wherein Y' is the image half height of the optical lens, FL is the focal length of the optical lens, and TTL is the distance from the object side of the first lens to an imaging plane.

Description

optical lens

This application is a divisional application of an invention patent application with an application date of August 29, 2014, an application number of 201410436387.5, and an invention title of "optical lens".

technical field

The invention relates to an optical lens, and in particular to an optical lens with wide angle and good imaging quality.

Background technique

Existing camera systems mainly include an optical lens and an image sensing module. Wherein, the optical lens can converge the light beam on the image sensing module, and the image sensing module converts the converged light beam into an image electronic signal, so as to store, process and transmit the image later.

The optical lens of the camera system is usually composed of several lenses. In order to increase the competitive advantage in the market, wide-angle, high image quality and cost reduction have always been the goals of product development.

Therefore, there is an urgent need to propose a new optical lens, which can achieve the purpose of wide-angle optical lens and improve imaging quality at the same time under the premise of reducing manufacturing cost.

Contents of the invention

The object of the present invention is to provide an optical lens. On the premise of providing good imaging quality, a wide-angle optical lens can be realized at the same time.

According to an embodiment of the disclosure, an optical lens is provided. The optical lens includes in sequence from the object side to the image side: a first lens with negative diopter, a second lens with negative diopter, a third lens with positive diopter, a fourth lens with positive diopter, and a The fifth lens has a negative diopter, wherein the thickness of the third lens is greater than 3 millimeters (mm), the second lens has an Abbe number vd2, and 10<vd2<50.

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

Description of drawings

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

FIG. 2 shows a graph of field curvature (field curvature) of an optical lens according to an embodiment of the present invention;

FIG. 3 shows a curve diagram of distortion (distortion) of an optical lens according to an embodiment of the present invention;

FIG. 4 shows a graph of lateral color aberration (lateral color) of an optical lens according to an embodiment of the present invention;

Fig. 5 shows the relative illumination (relative illumination) graph of the optical lens according to an embodiment of the present invention;

6 shows a graph of a modulation transfer function (modulus of the OTF) of an optical lens according to an embodiment of the present invention;

FIG. 7 illustrates an optical lens according to another embodiment of the present invention;

FIG. 8 shows a field curvature graph of an optical lens according to another embodiment of the present invention;

FIG. 9 shows a distortion curve diagram of an optical lens according to another embodiment of the present invention;

FIG. 10 shows a lateral chromatic aberration graph of an optical lens according to another embodiment of the present invention;

FIG. 11 shows a graph of relative brightness of an optical lens according to another embodiment of the present invention;

FIG. 12 is a graph of a modulation transfer function of an optical lens according to another embodiment of the disclosure.

Detailed ways

Various embodiments of the present invention will be described in detail below, and the accompanying drawings are used as examples. In addition to these detailed descriptions, the present invention can also be widely implemented in other embodiments, and any easy substitution, modification, and equivalent change of any of the described embodiments are included in the scope of the present invention, and the following claims range prevails. In the description of the specification, many specific details are provided in order to enable readers to have a more complete understanding of the present invention; however, the present invention may still be practiced under the premise of omitting some or all of these specific details. Also, well-known steps or elements have not been described in detail in order to avoid unnecessarily limiting the invention. The same or similar elements will be denoted by the same or similar symbols in the drawings. It should be noted that the drawings are for illustrative purposes only, and do not represent the actual size or quantity of components, unless otherwise specified.

FIG. 1 illustrates an optical lens OL1 according to an embodiment of the disclosure. In order to show the features of this embodiment, only structures related to this embodiment are shown, and other structures are omitted. The optical lens OL1 of this embodiment can be a wide-angle lens with a wide-angle level greater than 180 degrees, which can be applied to handheld communication systems, digital cameras, digital video cameras, automobiles, monitors or sports devices. In addition, the optical lens OL1 of this embodiment may also be a fixed-focus lens.

As shown in Figure 1, the optical lens OL1 of the present embodiment mainly includes in order from the object side (object side) to the image-forming side (image-forming side): a first lens L1 with negative diopter, a first lens L1 with negative diopter Two lenses L2, a third lens L3 with positive diopter, a fourth lens L4 with positive diopter, and a fifth lens L5 with negative diopter.

In a specific embodiment, the second lens L2 has an Abbe number vd2, and vd2 satisfies the condition of vd2<50, but not limited thereto.

In another embodiment, the Abbe number vd2 of the second lens L2 may satisfy 10<vd2<50; and in yet another embodiment, the Abbe number vd2 of the second lens L2 substantially satisfies 20<vd2<30.

In addition, the second lens L2 also has a refractive index nd2. In a specific embodiment, nd2 can satisfy the condition of nd2>1.6; in another embodiment, nd2 can also satisfy 2.2>nd2>1.6.

Moreover, in yet another specific embodiment, the third lens L3 has a refractive index nd3, and nd3 can satisfy the condition of nd3>1.8. In another embodiment, nd3 may also satisfy 2.2>nd2>1.8.

Further, in an embodiment, the thickness of the third lens L3 may be greater than 3 millimeters (mm). In another embodiment, the thickness of the third lens L3 may be between 3 mm and 6 mm.

Moreover, in yet another embodiment, the fifth lens L5 has a refractive index nd5, and nd5 can satisfy the condition of nd5>1.9. In another embodiment, nd5 can also satisfy 2.2>nd5>1.9.

On the other hand, in yet another embodiment, the fifth lens L5 can be made of high dispersion material. Specifically, the fifth lens L5 also has an Abbe number vd5, and vd5 can satisfy the condition of 15<vd5<25.

As shown in FIG. 1 , specifically, the optical lens OL1 may further include a stop St and a filter F. As shown in FIG. The diaphragm St can be arranged between the second lens L2 and the third lens L3, which helps to limit the luminous flux of the light beam; the filter F can be arranged between the fifth lens L5 and the imaging surface I, which helps to filter the light beam In the noise, the filter F can be an infrared filter (IRFilter). In addition, an image capture unit with a photoelectric conversion function is arranged on the imaging surface I, which can receive the light beam passing through the filter F and convert the optical signal into an electrical signal. And between the imaging surface I and the filter F, there is a plate glass C as a cover glass of the image capture unit.

Furthermore, the optical lens OL1 can also meet the condition of TTL<16 mm. Wherein, TTL is the distance from the object side of the first lens L1 to an imaging plane I. Specifically, TTL is the distance from the apex of the first surface of the first lens L1 to an imaging plane I. Wherein, the first surface is equal to the surface code S1 in Table 1 and Table 3.

In addition, the optical lens OL1 can also meet the condition of TTL/Y'<6.1. Wherein, Y' is the half-height of the image of the optical lens OL1.

Moreover, the optical lens OL1 can also meet the condition of Y'/FL>1.12. Wherein, FL is the focal length (focal length) of the optical lens OL1.

On the other hand, the optical lens OL1 can also satisfy the condition of FOV=(2×ω)≧135° (degree). Wherein, ω is the half field of view (half field of view) corresponding to the maximum value of Y', namely maxY'. In a specific embodiment, 210°≧FOV=(2×ω)≧135°.

Furthermore, the optical lens OL1 can also satisfy the condition of Fno<2.4. Wherein, Fno is the aperture coefficient of the optical lens OL1. In a specific embodiment, the f-number of the optical lens OL1 can satisfy 1.8<Fno<2.4.

Furthermore, in another embodiment, the aperture of the optical lens OL1 adopts a fixed aperture design.

In one embodiment, at least one of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 of the optical lens OL1 can be an aspheric lens and/or a free lens. curved lens. Wherein, at least one surface of the aspheric lens is aspherical, and at least one surface of the free-form surface lens is a free-form surface.

In this embodiment, the first lens L1 , the third lens L3 , the fourth lens L4 and the fifth lens L5 may be spherical lenses, and the second lens L2 may be an aspheric lens and have at least one aspheric surface. Specifically, the aspheric surface of the second lens L2 can satisfy the following mathematical formula:

Among them, Z is the coordinate value in the direction of the optical axis OA, with the light transmission direction as the positive direction, A4, A6, A8 and A10 are the aspheric coefficients, K is the quadric surface constant, C=1/R, and R is the radius of curvature , Y is the coordinate value perpendicular to the direction of the optical axis OA, and the upward direction is the positive direction. In addition, the values of various parameters or coefficients of the aspheric mathematical formula of the aspheric lens can be set separately to determine the focal length of the aspheric lens.

In another embodiment, the second lens L2 may be a free-form lens, wherein the free-form lens has at least one free-form surface. Specifically, the second lens L2 can be a free-form surface lens or an aspheric lens. Alternatively, the second lens L2 may have an aspheric surface and a free-form surface at the same time, but is not limited thereto.

In addition, in this embodiment, the first lens L1, the third lens L3, the fourth lens L4, and the fifth lens L5 can be glass lenses made of glass materials, and the material of the second lens L2 can be made of plastic materials. Plastic lens, wherein, the plastic material may include, but not limited to, polycarbonate (polycarbonate), cycloolefin copolymer (such as APEL), and polyester resin (such as OKP4 or OKP4HT), etc., or include the aforementioned three The mixed material of at least one of them, but not limited thereto, in another embodiment, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 can all use glass lens.

As shown in Figure 1, the first lens L1 is a convex-convex lens with a convex surface facing the object side, the second lens L2 is a convex-concave lens with a convex surface facing the object side, the third lens L3 is a biconvex lens, and the fourth lens L4 is It is a biconvex lens, and the fifth lens L5 is a meniscus lens with a convex surface facing the image side.

In an embodiment, as shown in FIG. 1 , the fourth lens L4 and the fifth lens L5 can be cemented into a cemented lens.

In some embodiments, as shown in FIG. 1 , the first lens L1 , the second lens L2 , the third lens L3 , the fourth lens L4 and the fifth lens L5 are respectively movable along the optical axis OA of the optical lens OL1 .

Table 1 lists the detailed data of an embodiment of the optical lens OL1 as shown in FIG. 1 according to the present invention, which includes the radius of curvature, thickness, refractive index, and dispersion coefficient of each lens. The surface codes of the lenses are arranged sequentially from the object side to the image side, for example: "S1" represents the surface of the first lens L1 facing the object side, "S2" represents the surface of the first lens L1 facing the image side, "S" represents The stop surfaces, "S12" and "S13" represent the object-side and image-side surfaces of the filter F, respectively, while the object-side and image-side surfaces of the plate glass C are "S14" and "S15" respectively, and so on. In addition, "thickness" represents the distance between the surface and a surface adjacent to the image side, for example, the "thickness" of surface S1 is the distance between surface S1 and surface S2, and the "thickness" of surface S2 is the distance between surface S2 and surface S3 .

Table I

In addition, for the two surfaces of the second lens L2 in the above embodiment, that is, the surfaces code-named "S3" and "S4", the coefficients in the aspheric mathematical formula are shown in Table 2.

Table II

K A4 A6 A8 A10 S3 0 -2.6192748E-04 7.1600248E-05 -3.1777018E-05 -4.3788000E-05 S4 0 9.0668609E-03 1.2372975E-04 -1.4888306E-03 7.3356400E-04

FIG. 2 illustrates a field curvature curve of the optical lens OL1 according to an embodiment of the disclosure. Wherein, curves T and S respectively show the aberrations of the optical lens OL1 for tangential rays (Tangential Rays) and sagittal rays (Sagittal Rays). The figure shows that the tangent field curvature and sagittal field curvature of the light beams with wavelengths of 486nm, 588nm and 656nm are all controlled within a good range.

FIG. 3 shows a distortion curve of the optical lens OL1 according to an embodiment of the disclosure. The figure shows that the distortion rates of the light beams with wavelengths of 486nm, 588nm and 656nm are all controlled within the range of (-120%, +0%).

FIG. 4 is a graph showing the lateral color aberration (lateral color) of the optical lens OL1 according to an embodiment of the present invention, which shows that the chromatic aberration can be controlled within the range of (-1.2 μm, 3.1 μm).

Fig. 5 shows the relative illumination (relative illumination) graph of the optical lens OL1 according to an embodiment of the content of the present invention, and Fig. 6 shows the modulation transfer function (modulus of the optical lens OL1) according to an embodiment of the content of the present invention OTF) graph.

It can be seen from FIGS. 2 to 6 that the field curvature, distortion, lateral chromatic aberration, relative brightness and modulation transfer function of the optical lens OL1 of this embodiment can all be well corrected.

FIG. 7 illustrates an optical lens OL2 according to another embodiment of the disclosure. The structure of the optical lens OL2 of this embodiment is roughly the same as that of the optical lens OL1 of the embodiment shown in FIG. rate, dispersion coefficient, etc. The differences are described below with examples, and the previous descriptions can be used for the same points, so no more details are given.

In this embodiment, the first lens L1 , the second lens L2 , the third lens L3 , the fourth lens L4 and the fifth lens L5 of the optical lens OL2 may all be spherical lenses.

On the other hand, the first lens L1 , the second lens L2 , the third lens L3 , the fourth lens L4 and the fifth lens L5 of the optical lens OL2 may all be glass lenses made of glass materials.

Table 3 lists the detailed data of an embodiment of the optical lens OL2 as shown in FIG. 7 according to the present invention, which includes the radius of curvature, thickness, refractive index, and dispersion coefficient of each lens. The respective codes are the same as those in the foregoing embodiments, and will not be repeated here.

Table three

FIG. 8 illustrates a field curvature curve of the optical lens OL2 according to an embodiment of the disclosure. Wherein, the curves T and S respectively show the aberrations of the optical lens OL2 for the tangential beam and the sagittal beam. The figure shows that the tangent field curvature and sagittal field curvature of the light beams with wavelengths of 486nm, 588nm and 656nm are all controlled within a good range.

FIG. 9 is a graph showing the distortion curve of the optical lens OL2 according to an embodiment of the disclosure. The figure shows that the distortion rates of the light beams with wavelengths of 486nm, 588nm and 656nm are all controlled within the range of (-120%, +0%).

FIG. 10 shows a lateral chromatic aberration curve of the optical lens OL2 according to an embodiment of the disclosure, which shows that the chromatic aberration can be controlled within the range of (-0.9 μm, 2.3 μm).

FIG. 11 shows a graph of relative brightness of the optical lens OL2 according to an embodiment of the present invention, and FIG. 12 shows a graph of a modulation transfer function of the optical lens OL2 according to an embodiment of the present invention.

It can be seen from FIGS. 8 to 12 that the field curvature, distortion, lateral chromatic aberration, relative brightness and modulation transfer function of the optical lens OL2 of this embodiment can all be well corrected.

Certainly, the present invention also can have other multiple embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding Changes and deformations should belong to the scope of protection of the appended claims of the present invention.

Claims (12)

1. a kind of optical lens, which is characterized in that include sequentially from object side to image side：One there is negative diopter the first lens, One has the second lens of negative diopter, the 4th lens with positive diopter of the third lens with positive diopter, one and One there are the 5th lens of negative diopter, the wherein thickness of the third lens to be more than 3 millimeters, which has Abbe number Vd2,10<vd2<50, and the optical lens also meets Y '/FL>1.12 and/or TTL/Y '<6.1, wherein Y ' are the optical lens Image half is high, focal length that FL is the optical lens and TTL are distances from the object side of first lens to an imaging surface.

2. optical lens according to claim 1, which is characterized in that second lens have refractive index nd2, and nd2> 1.6。

3. optical lens according to claim 1, which is characterized in that second lens are that a spherical lens or one are aspherical Lens.

4. optical lens according to claim 1, which is characterized in that the third lens are that a biconvex lens or a spherical surface are saturating Mirror.

5. optical lens according to claim 1, which is characterized in that the third lens have refractive index nd3, and nd3> 1.8。

6. optical lens according to claim 1, which is characterized in that the 5th lens have Abbe number vd5 and refractive index Nd5, and 15<vd5<25 and/or nd5>1.9.

7. optical lens according to claim 1, which is characterized in that the 4th lens and the 5th lens compose a glue Close lens.

8. optical lens according to claim 1, which is characterized in that the optical lens also meets the following conditions：TTL<16 Millimeter, distances of the wherein TTL from the object side of first lens to an imaging surface.

9. optical lens according to claim 1, which is characterized in that the optical lens also meets the following conditions：Fno< 2.4, wherein Fno are the aperture-coefficients of the optical lens.

10. optical lens according to claim 1, which is characterized in that the optical lens also meets the following conditions：(2× ω)≤135 °, wherein ω is Y ' when being maximum value half-field angle, Y ' are that the image half of the optical lens is high.

11. optical lens according to claim 1, which is characterized in that the optical lens further includes a diaphragm, is set to this Between second lens and the third lens.

12. optical lens according to claim 1, which is characterized in that first lens, the third lens, the 4th are thoroughly Mirror and the 5th lens are glass lens, which is a plastic lens or a glass lens.