KR101804332B1 - Camera lens module - Google Patents

Abstract

The present invention relates to a camera lens module in which an optical system is constituted by three lenses. According to the present invention, there is provided a zoom lens comprising, in order from an object side, a first lens; A second lens; And a third lens which is convex on both sides and has no inflection point, wherein the first lens, the second lens and the third lens are made of glass. According to the present invention, all the lenses of the optical system are made of a glass material, and the third lens is made a two-sided convex, eliminating inflection points, glass molding can be performed, and a reflow process can be used.

Description

[0001] The present invention relates to a camera lens module,

The present invention relates to a camera lens module, and more particularly, to a camera lens module in which a lens constituting an optical system is made of a glass material and glass molding is enabled so that a reflow process can be used.

Mobile phone handsets are gradually evolving with increasing usage, and various functions and services are being developed. 2. Description of the Related Art A mobile terminal such as a mobile phone terminal or a smart phone has a camera and photographs a photograph or a moving image, stores the photographed image, or provides a service for image communication. Recently, a camera module is installed in most portable terminals. That is, the demand for ultra-small camera modules is increasing rapidly.

The camera module usually forms an exterior by molding plastic injection molding. And lenses also mold some lenses into plastic materials. However, a considerable amount of time is required in the molding process using the plastic material, and the lens module including the plastic material is vulnerable to the heat at high temperature, so that the mass production process such as the reflow process can not be utilized.

It is an object of the present invention to provide a camera lens module which is capable of glass molding the structure of an optical system, ensures mass productivity using a reflow process, and has excellent aberration characteristics.

A camera lens module according to an embodiment of the present invention includes, in order from an object side, a first lens; A second lens; And a third lens which is convex on both sides and has no inflection point, and the first lens, the second lens and the third lens are made of a glass material.

In the camera lens module according to another embodiment of the present invention, the first lens, the second lens, and the third lens are molded of a glass material.

In the camera lens module according to another embodiment of the present invention, the first lens has a positive refractive power.

In the camera lens module according to another embodiment of the present invention, the first lens has a meniscus shape.

In the camera lens module according to another embodiment of the present invention, the second lens has a negative refractive power.

In the camera lens module according to another embodiment of the present invention, the second lens has a meniscus shape.

In the camera lens module according to another embodiment of the present invention, the diaphragm of the optical system is located between the first lens and the second lens.

In the camera lens module according to another embodiment of the present invention, an infrared ray filter is provided between the third lens and the imaging plane.

In a camera lens module according to another embodiment of the present invention, at least one of the first lens, the second lens, and the third lens has at least one aspherical surface.

In the camera lens module according to another embodiment of the present invention, the first lens, the second lens, and the third lens are aspherical surfaces on both sides.

The camera lens module according to still another embodiment of the present invention satisfies the following conditional expression 1 with respect to the focal length of the first lens and the focal length of the entire optical system.

(Conditional expression 1) 0.5 < f1 / f < 1.5

Here, f1: the focal length of the first lens

f: focal length of the entire optical system

The camera lens module according to still another embodiment of the present invention satisfies the following conditional expression 2 with respect to the focal length of the first lens and the focal length of the second lens.

(Conditional expression 2) | f2 / f1 | > 1

Here, f1: the focal length of the first lens

f2: focal length of the second lens

The camera lens module according to another embodiment of the present invention satisfies the following conditional expression (3) with respect to the distance from the object side of the first lens to the imaging plane and the focal length of the entire optical system.

(Conditional expression 3) 0.5 < T / f < 1.5

Here,? T: the distance from the object side surface of the first lens to the image plane

f: focal length of the entire optical system

The camera lens module according to still another embodiment of the present invention satisfies the following conditional expression (4) with respect to the radius of curvature of the object side surface and the radius of curvature of the image side surface of the third lens.

(Conditional expression 4) (R31-R32) / 2 > 5

Here, R31: the object side curvature radius of the third lens

R32: the radius of curvature of the image side of the third lens

The camera lens module according to still another embodiment of the present invention satisfies the following conditional expression 5 with respect to the radius of curvature of the object side surface of the first lens and the focal length of the entire optical system.

(Conditional expression 5) 0 < R11 / f < 0.5

Here, R11: the object side curvature radius of the first lens

f: focal length of the entire optical system

The camera lens module according to still another embodiment of the present invention satisfies the following conditional expression 6 with respect to the Abbe number of the first lens.

(Conditional expression 6) v1 > 50

Here, v1: Abbe number of the first lens

The camera lens module according to still another embodiment of the present invention satisfies the following conditional expression 7 with respect to the Abbe number of the second lens.

(Conditional expression 7) 20 <v2 <30

Here, v2: Abbe number of the second lens

According to the camera lens module of the present invention, an optical system is constituted by a first lens having a positive refractive power, a second lens having a negative refractive power, and a third lens having no inflection point having a convex shape on both sides, By making glass molding possible by using the material, the reflow process can be used and the mass productivity is greatly improved.

1 is a block diagram of a camera lens module according to the present invention;
2 is a graph showing aberration characteristics according to an embodiment of the present invention,
3 and 4 are graphs showing coma aberration characteristics according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and a duplicate description thereof will be omitted.

FIG. 1 is a side view of a camera lens module according to the present invention, illustrating the arrangement of lenses around an optical axis Z0. 1, the camera lens module of the present invention is composed of three optical systems in which a first lens 10, a second lens 12, and a third lens 14 are arranged in order from the object side . All three lenses are made of glass.

Behind the third lens 14, an infrared filter 16 and an imaging surface 18 for filtering the infrared wavelength are located. The image pickup surface 18 is provided with an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) as a surface on which images are formed.

In describing the structures of the first lens 10, the second lens 12 and the third lens 14 in the following description, the term "object side surface" means the surface of the lens facing the object side with respect to the optical axis , And the term "upper side" refers to the surface of the lens that faces the imaging surface 18 with respect to the optical axis.

The first lens 10 has a positive refractive power. As an example, the first lens 10 has a meniscus shape whose object side is convex. As shown in the drawing, the first surface S1, which is the object side surface of the first lens 10, is convex on the object side and the second surface S2 on the upper side is concave upward.

A stop 20 of the optical system is positioned between the first lens 10 and the second lens 12.

The second lens 12 has a negative refractive power. For example, the second lens 12 has a meniscus shape whose upper side is convex. As shown in the drawing, the fourth surface S4, which is the object side surface of the second lens 12, is concave toward the object side and the fifth surface S5 which is the upper side is convex upward.

The third lens 14 has a positive refractive power. That is, the optical system composed of three lenses is arranged with positive, negative and positive refractive powers. The third lens 14 has a convex shape on both sides S6 and S7 and has no inflection point. As shown in the drawing, the sixth surface S6 which is the object side surface of the third lens 14 is convex toward the object side, and the seventh surface S7 which is the upper side is convex upward.

At least one of the lenses of the first lens 10, the second lens 12 and the third lens 14 is formed as an aspherical surface on at least one side. According to the embodiment mentioned below with reference to the table, the first lens 10, the second lens 12 and the third lens 14 are both aspherical surfaces on both sides.

In the camera lens module of the present invention, the shape of the third lens 14 is a two-sided convex shape and an inflection point is eliminated. And the total optical system is composed of glass material. Therefore, the optical system can be molded by glass molding, and the reflow process can be used.

The present invention provides conditions for improving the resolving power of a lens, correcting chromatic aberration, and reducing distortion aberration through the above-described optical system lens configuration. It will be apparent to those skilled in the art that the conditional expressions and examples described below are preferred embodiments for enhancing the operational effects of the present invention, and that the present invention is not necessarily constituted by the following conditions. For example, the lens configuration of the present invention may have an elevated action effect even if only the conditional formulas of some of the conditional expressions described below are satisfied.

First, the conditional expression relating to the focal length of the optical system is as follows.

(Conditional expression 1) 0.5 < f1 / f < 1.5

(Conditional expression 2) | f2 / f1 | > 1

(Conditional expression 3) 0.5 < T / f < 1.5

Here, f1: the focal length of the first lens

f2: focal length of the second lens

f: focal length of the entire optical system

? T: a distance from the object side surface of the first lens to the image plane

From the conditional expressions 1 to 3, it can be understood that the ultra-small imaging lens module is designed with lenses having the positive, negative, and positive refracting power in the interval and focal distance of each lens constituting the optical system.

Next, the conditional expression related to the radius of curvature of the lenses is as follows.

(Conditional expression 4) (R31-R32) / 2 > 5

(Conditional expression 5) 0 < R11 / f < 0.5

Here, R31: the object side curvature radius of the third lens

R32: the radius of curvature of the image side of the third lens

R11: radius of curvature of the object side surface of the first lens

The above Conditional Expression 4 and Conditional Expression 5 show an example of improving the resolving power of the lens while designing the lens module to be very small according to the present invention.

The conditional expression related to the Abbe number of each lens is as follows.

(Conditional expression 6) v1 > 50

(Conditional expression 7) 20 <v2 <30

Here, v1: Abbe number of the first lens

v2: Abbe number of the second lens

According to the conditional expressions 6 and 7, it can be seen that the Abbe number of the first lens 10 can be selected to be larger than the Abbe number of the second lens 12. This is to ensure a certain degree of chromatic aberration correction.

Hereinafter, the present invention will be described with reference to specific numerical examples. Table 1 below shows an embodiment that satisfies the above conditional expressions.

Refractive index (N) f 3.0 f1 2.10 f2 -4.57 T 3.50 R11 0.80 R31 9.76 R32 -30.0 v1 81 v2 23

Table 2 below shows an embodiment on each side of the lens (S1 to S9). The face numbers in the table correspond to the faces indicated by S1 to S9 in Fig. The addition of "*" next to the face number indicates the aspherical surface.

Face number The radius of curvature (R) Distance (d) Refractive index (N) One* 0.80 0.071 1.49 2* 2.39 0.1 3 ∞ 0.38 4* -0.69 0.40 1.84 5 * -1.07 0.10 6 * 9.76 0.70 1.73 7 * -30.0 0.10 8 ∞ 0.30 1.52 9 ∞ 0.71 image ∞ -0.01

Table 3 below shows the aspherical surface coefficients on each surface.

Face number K A B C D E F One* -0.009266 -0.168684
E-01 0.877372
E-01 -0.627210
E + 00 0.161234
E + 01 -0.179063
E + 01 0.000000 2* -35.38185 0.336877
E + 00 -0.313360
E + 00 -0.203462
E + 01 0.772364
E + 01 0.000000 0.000000 4* 0.816094 0.187209
E-02 0.343901
E + 01 -0.302767
E + 02 0.138957
E + 03 -0.250702
E + 03 0.000000 5 * -4.876595 -0.424741
E + 00 0.721413
E + 00 -0.122964
E + 01 0.112120
E + 01 -0.380466
E + 00 -0.135471
E + 00 6 * 0.000000 -0.196570
E-01 0.208902
E-01 -0.642049
E-02 0.576346
E-03 -0.200900
E-04 0.000000 7 * 0.000000 -0.675187
E-01 0.120363
E-01 0.204186
E-02 -0.184255
E-03 -0.183103
E-03 0.000000

The aspherical equations for each aspheric coefficient in Table 3 are as follows.

Here, Z is the distance from the apex of the lens in the direction of the optical axis

C: curvature of the lens

Y: Distance in the direction perpendicular to the optical axis

K: Conic constant

A, B, C, D, E, F: Aspheric constant

2 is a graph showing aberration diagrams according to the lens configuration described above with reference to FIG. 1 and the embodiments of Tables 2 and 3. FIG. 2 (a) is a graph showing longitudinal spherical aberration (B) is a graph showing astigmatic field curves, and (c) is a graph showing distortion aberration.

In Fig. 2, the Y axis represents the size of the image, and the X side represents the focal length (in mm) and distortion (in%). In FIG. 2, as the curves approach the Y-axis, it is interpreted that the aberration correction function is better. In the illustrated aberration chart, the spherical aberration is 0.025 unit, and the astigmatism image plane curvature is located within 0.04 unit, which is a very good numerical value.

FIGS. 3 and 4 show the coma aberration characteristics of the embodiment of the camera lens module according to the present invention, and show tangential and sagittal aberration characteristics according to respective wavelengths.

In FIGS. 3 and 4, as the graph showing the experimental results is closer to the X axis on the positive axis and the negative axis, respectively, it is interpreted that the ray aberration correction function is good, and all of the measurement examples shown show excellent ray aberration correction function do.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention. You will understand. Accordingly, it is intended that the present invention covers all embodiments falling within the scope of the following claims, rather than being limited to the above-described embodiments.

10: first lens 12: second lens
14: Third lens 16: Infrared filter
18: image plane 20: aperture

Claims (19)

In order from the object side,
A first lens made of a glass material;
A second lens made of a glass material; And
And a third lens which is made of a glass material whose both surfaces are convex and have no inflection point,
A camera lens module satisfying the following conditional expressions 1, 3, 5, 7,
(Conditional expression 1) 0.5 < f1 / f < 1.5
(Conditional expression 3) 0.5 < T / f < 1.5
(Conditional expression 5) 0 < R11 / f < 0.5
(Conditional expression 7) 20 <v2 <30
(Conditional expression 8) | R31 | <| R32 |
Here, f1: the focal length of the first lens
f: focal length of the entire optical system
? T: a distance from the object side surface of the first lens to the image plane
R11: radius of curvature of the object side surface of the first lens
R31: radius of curvature of the object side surface of the third lens
R32: the radius of curvature of the image side of the third lens
v2: Abbe number of the second lens
The method according to claim 1,
Wherein the first lens, the second lens, and the third lens are molded of a glass material.
The method according to claim 1,
Wherein the first lens has a positive refractive power,
And the second lens has a negative refracting power.
The method of claim 3,
Wherein the first lens has a meniscus shape.
delete The method of claim 3,
And the second lens has a meniscus shape.
The method according to any one of claims 1 to 4 or 6,
And a diaphragm of the optical system is located between the first lens and the second lens.
The method according to any one of claims 1 to 4 or 6,
And an infrared filter is provided between the third lens and the imaging plane.
The method according to any one of claims 1 to 4 or 6,
Wherein at least one of the first lens, the second lens, and the third lens is at least one aspherical surface.
The method according to any one of claims 1 to 4 or 6,
Wherein the first lens, the second lens, and the third lens are aspheric on both sides.
delete The method according to any one of claims 1 to 4 or 6,
Wherein the following conditional expression (2) is satisfied with respect to the focal length of the first lens and the focal length of the second lens.
(Conditional expression 2) | f2 / f1 | > 1
Here, f1: the focal length of the first lens
f2: focal length of the second lens
delete The method according to any one of claims 1 to 4 or 6,
Satisfies the following conditional expression (4) with respect to the radius of curvature of the object side surface and the radius of curvature of the image side surface of the third lens.
(Conditional expression 4) (R31-R32) / 2 > 5
Here, R31: the object side curvature radius of the third lens
R32: the radius of curvature of the image side of the third lens
delete The method according to any one of claims 1 to 4 or 6,
Wherein the Abbe number of the first lens satisfies the following conditional expression (6).
(Conditional expression 6) v1 > 50
Here, v1: Abbe number of the first lens
delete A camera lens module according to any one of claims 1 to 4 or 6;
An infrared ray filter provided between the third lens and the imaging plane; And
A camera module comprising an image sensor mounted on an imaging surface.
A mobile phone terminal comprising the camera module of claim 18.

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