KR101626551B1 - Lens module - Google Patents

Abstract

The present invention relates to a lens module, and more particularly, to a lens module suitable for a camera module using a high-resolution image sensor and having a plurality of lenses to reduce the sensitivity.

A lens module of the present invention comprises, in order from an object side, a first lens having a positive refractive power; A second lens having a negative refractive power; A third lens having positive refractive power; A fourth lens having positive refractive power; A fifth lens having positive refractive power; And a sixth lens having negative refracting power, wherein the fourth lens is formed such that the object side surface is convex.

Lens, imaging

Description

LENS MODULE {LENS MODULE}

The present invention relates to a lens module, and more particularly, to a lens module suitable for a camera module using a high-resolution image sensor and having a plurality of lenses to reduce the sensitivity.

Recently, a camera module for a communication terminal, a digital still camera (DSC), a camcorder, a PC camera (an image pickup device attached to a personal computer), and the like have been studied in connection with an image pick-up system . A most important component for obtaining an image of a camera module related to such an image pickup system is a lens module having a plurality of lens modules for imaging an image.

Attempts have been made to construct a high-resolution lens module using five lenses. Each of the five lenses is composed of a lens having a positive refractive power and a lens having a negative refractive power. For example, the lens module is constructed in the order of PNNPN (+ - + -), PNPNN (+ - + -), or PPNPN (++ - + -) from the object side. However, the lens module having such a structure does not exhibit satisfactory optical characteristics or aberration characteristics in some cases, and a high-resolution lens module having a new power structure is required.

An object of the present invention is to provide a lens module having a new power structure in which the number of lenses is increased, and to provide a lens module having a characteristic of reducing a flare phenomenon and reducing sensitivity and having aberration characteristics.

In particular, it is an object of the present invention to provide a lens module that improves the performance of the lens module as the pixel size of the image sensor becomes smaller.

According to an aspect of the present invention, there is provided a lens module comprising: a first lens having, in order from an object side, a positive refractive power; A second lens having a negative refractive power; A third lens having positive refractive power; A fourth lens having positive refractive power; A fifth lens having positive refractive power; And a sixth lens having negative refracting power, wherein the fourth lens is formed such that the object side surface is convex.

In the lens module of the present invention, at least one of the object side surface and the image side surface of the first lens to the sixth lens is an aspherical surface.

In the lens module of the present invention, the fifth lens is concave on the object side.

In the lens module of the present invention, the sixth lens is formed so that the object side surface is convex.

In the lens module of the present invention, the sixth lens has inflection points on both the object side and the upper side.

In the lens module of the present invention, when the total focal length of the lens module is f and the focal length of the first lens is f1, 0.5 <f1 / f <1.5 is satisfied.

In the lens module of the present invention, when the Abbe number of the second lens is V2 and the Abbe number of the third lens is V3, 20 <V2 and V3 <30 are satisfied.

In the lens module of the present invention, when the Abbe number of the fourth lens is V4, the Abbe number of the fifth lens is V5, and the Abbe number of the sixth lens is V6, 50 <V4, V5, Is satisfied.

Further, in the lens module of the present invention, when the total focal length of the lens module is denoted by f and the total thickness of the lens module is denoted by d, 0.5 <d / f <1.5 is satisfied.

In the lens module of the present invention, when the focal length of the first lens is f1 and the focal length of the second lens is f2, the conditional expression | f2 / f1 |> 1 is satisfied.

The lens module according to the present embodiment is characterized in that the first lens and the third lens to the fifth lens have a positive power and the second lens and the sixth lens are formed of a lens having a negative power The lens module is a power structure of the PNPPPN.

Further, the fourth lens can be realized with a lens module in which the object side is convex so that the flare phenomenon is reduced and the sensitivity is reduced while the aberration characteristic is excellent.

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.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component.

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, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, a lens module according to an embodiment of the present invention will be described in detail with reference to the drawings, and the same or corresponding components are denoted by the same reference numerals regardless of the reference numerals, and redundant explanations thereof are omitted.

Fig. 1 is a configuration diagram of a camera lens module according to the present embodiment, and is a side view showing an arrangement state of lenses around an optical axis Z0. In the configuration diagram of Fig. 1, the thickness, size, and shape of the lens are shown somewhat exaggerated for explanatory purposes, and the spherical or aspherical shape is not limited to this shape, but only one embodiment.

 1, a camera lens module according to the present invention includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 40, 50, a sixth lens 60, a filter 70, and a light receiving element 80 are arranged.

The light corresponding to the image information of the object is incident on the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, the sixth lens 60 And the filter 70 and is incident on the light receiving element 80. [

The term " object side surface "refers to a surface of the lens facing the object side with respect to the optical axis, and" upper surface " Means the face of the lens.

The first lens 10 has a positive refractive power, and the object side surface S1 is convex. The object-side surface S1 of the first lens 10 may serve as a diaphragm. In this case, the lens module of this embodiment does not require a separate diaphragm. The second lens 20 has a negative refracting power and the object side surface S3 is convex.

The third lens 30, the fourth lens 40 and the fifth lens 50 have a positive refractive power and the sixth lens 60 has a negative refractive power. As shown in the figure, the third lens 30 is in the form of a meniscus in which the object side surface S5 is formed convexly. The refractive power of the third lens 30 is formed to be smaller than the refractive power of the remaining lenses. The third lens 30 is formed so that the object side surface S5 is convex so that the flare phenomenon in which the image is spread is reduced and the sensitivity of the lens is reduced.

The first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, and the sixth lens 60 have at least an object- Any one surface may be formed of an aspheric surface, but the present invention is not limited thereto. Both surfaces may be provided with aspherical surfaces.

Here, the sixth lens 60 is an aspherical shape in which both the object side surface S11 and the upper side surface S12 have inflection points. As shown in the figure, the upper surface S12 of the sixth lens 60 is bent upward toward the periphery from the central portion with the optical axis Z0 as its center, and again, at the peripheral portion away from the optical axis Z0, It is bent toward the object side to form an aspheric inflection point.

The aspheric inflection point formed in the sixth lens 60 can adjust the maximum emission angle of the principal ray incident on the light receiving element 70. The aspherical surface inflection point formed on the object side surface S11 and the upper surface S12 of the sixth lens 60 adjusts the maximum projection angle of the principal ray to prevent the shadow of the peripheral portion of the screen from becoming shaded.

The filter 70 is at least one of an infrared filter, an optical filter such as a cover glass, and the like. When the infrared filter is applied as the filter 70, the radiant heat emitted from the external light is blocked from being transmitted to the light receiving element 80. In addition, the infrared ray filter transmits visible light, and the infrared ray reflects the infrared ray to the outside.

The light receiving element 80 is an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

The first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, and the sixth lens 60, as in the following embodiments, By using a lens having at least one surface or both surfaces of an aspherical surface, it is possible to improve the resolving power of the lens and to take advantage of the excellent aberration characteristics.

It will be apparent to those skilled in the art that the conditional expressions and embodiments described below are preferred embodiments for increasing the operating effect, 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.

[Conditional expression 1]

0.5 < f1 / f < 1.5

[Conditional expression 2]

20 < V2, V3 < 30

[Conditional expression 3]

50 < V4, V5, V6 < 60

[Conditional expression 4]

0.5 < d / f < 1.5

[Conditional expression 5]

| F2 / f1 | > 1

here,

f: Overall focal length of lens module

f1: focal length of the first lens

V1 to V6: Abbe number of the first to sixth lenses

d: Overall thickness of the lens module

.

Conditional expression 1 defines the refractive power of the first lens 10. The first lens 10 has a refractive power with proper chromatic aberration and correction of the appropriate spherical aberration according to the conditional expression (1). Conditions 2 and 3 define the Abbe number of each lens. The definition of the refractive index and Abbe number of each lens is a condition for satisfactorily correcting the chromatic aberration. The conditional expression 5 is a condition capable of downsizing the lens module while correcting the magnification and the abstract chromatic aberration.

Hereinafter, the operation and effect of the present invention will be described with reference to specific examples. Conic constants k mentioned in the following examples and 'E and the numbers following' used in the aspherical coefficients A, B, C, D, E and F indicate powers of ten. For example, E + 01 represents 10 ¹ and E-02 represents 10 ^-2 .

[Example]

[Table 1]

Face number The radius of curvature (R) Thickness (d) Refractive index (N) One* 4.06 1.00 1.53 2* -2.49 0.20 3 * 9.04 0.43 1.61 4* 1.97 0.38 5 * 111.8 0.43 1.61 6 * -111.4 0.36 7 * -5.60 0.48 1.53 8* -5.00 0.20 9 * -4.12 0.86 1.53 10 * -1.14 0.20 11 * 6.96 0.52 1.53 12 * 1.07 0.65 13 0.00 0.30 1.52 14 0.00 0.56 Image 0.00 0.00

In Table 1, the symbol * next to the surface number indicates an aspherical surface.

The embodiment of Table 1 is a concrete example of Conditional Expressions 1 to 5, and the values of the aspherical surface coefficients of the respective lenses in the embodiment of Table 1 are shown in Table 2 below.

[Table 2]

FIG. 2 is a graph showing aberration diagrams according to the above embodiment. FIG. 2 is a graph showing longitudinal spherical aberration, astigmatic field curves, and distortion in order from the left.

In Fig. 2, the Y axis means the size of the image, and the X side means the focal length (in mm) and the distortion degree (in%). In FIG. 2, as the curves approach the Y-axis, the aberration correction function is considered to be better. In the illustrated aberration diagrams, since the values of the images are adjacent to the Y axis in almost all fields, spherical aberration, astigmatism, and distortion aberration are all excellent values.

FIG. 3 is a graph of coma aberration, and FIG. 3 is a graph showing a tangential aberration and a sagittal aberration of each wavelength according to the height of the top surface. In FIG. 3, as the graph showing the experimental results is closer to the X axis on the positive axis and the negative axis, it is interpreted that the coma aberration correction function is good. The measurement examples of FIG. 3 are interpreted as showing superior coma aberration correction functions because the values of the images appear near the X axis in almost all fields.

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.

1 is a configuration diagram of a lens module according to the present embodiment.

2 is a graph showing aberration characteristics according to an embodiment of the present invention.

3 is a graph showing coma aberration according to an embodiment of the present invention.

Claims (10)

In order from the object side, A first lens having positive refractive power; A second lens having a negative refractive power; A third lens having positive refractive power; A fourth lens having positive refractive power; A fifth lens having positive refractive power; And And a sixth lens having a negative refractive power, Wherein the fourth lens and the sixth lens are convex on the object side. The method according to claim 1, Wherein the first lens to the sixth lens are aspherical surfaces on at least one side or both sides of the object side surface and the upper side surface. The method according to claim 1, And the fifth lens has a concave surface on the object side. delete 5. The method of claim 4, And the sixth lens has an inflection point on both the object side surface and the image side surface. The method according to claim 1, When the total focal length of the lens module is f and the focal length of the first lens is f1, 0.5 < f1 / f < 1.5 Lt; / RTI &gt; The method according to claim 1, When the Abbe number of the second lens is V2 and the Abbe number of the third lens is V3, 20 < V2, V3 < 30 Lt; / RTI &gt; The method according to claim 1, When the Abbe number of the fourth lens is V4, the Abbe number of the fifth lens is V5, and the Abbe number of the sixth lens is V6, 50 < V4, V5, V6 < 60 Lt; / RTI &gt; The method according to claim 1, The total focal length of the lens module is f, and the total thickness of the lens module, which is the distance from the object-side incident surface of the first lens to the image surface, 0.5 < d / f < 1.5 Lt; / RTI &gt; The method according to claim 1, When the focal length of the first lens is f1 and the focal length of the second lens is f2, | F2 / f1 | > 1 Lt; / RTI &gt;

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