KR20120071797A - A super wide angle camera lens for surveillance - Google Patents

Abstract

PURPOSE: A super wide angle camera lens for monitoring is provided to photograph a very wide range of view by employing an optical system having an image angle of 190 degrees or greater and a small thickness of about 14mm or less. CONSTITUTION: A first lens(L1) has one aspherical surface and a meniscus shape convex toward an object. A second lens(L2) is concave on both sides thereof. A third lens(L3) has one aspherical surface and a meniscus shape convex toward an object. A fourth lens(L4) is convex on both sides thereof. A fifth lens(L5) is convex on both sides thereof. A sixth lens(L6) has one concave surface attached to the fifth lens and the other surface flat. An aperture(AS) is interposed between the third and fourth lenses and allows only light necessary for image forming to pass.

Description

Super Wide Angle Camera Lens for Surveillance

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a super wide angle camera lens for surveillance, and more particularly, to an ultra wide angle, ultra thin surveillance super wide angle camera lens having an angle of view of more than 190 degrees.

In general, a mobile communication terminal, a computer, a laptop, and a vehicle are equipped with a camera to display or photograph surrounding image information, and according to a tendency of slimming of a mobile communication terminal or a miniaturization of a computer or a laptop, etc. In addition, it is required to have a small size, light weight and high image quality, and a small size, light weight, high quality camera is required in order to avoid obstructing the aesthetics of the driver even in a vehicle camera.

In addition, such a camera should be able to obtain a wide range of image information as possible by having a small, lightweight, high-definition and large wide angle.

However, attempting to maintain a wide wide angle to obtain a wide range of image information, while miniaturizing the size of the camera, has appeared to be a problem that makes the distortion of the wide angle lens more severe.

In order to solve this problem, a conventionally proposed ultra wide-angle optical system capable of obtaining a small size, light weight, high quality and surrounding image information widely.

As shown in FIG. 1, the ultra wide-angle optical system has a meniscus-shaped first lens L1 disposed on the optical axis and having negative refractive power and convex toward the object, and a meniscus shape having negative refractive power and convex toward the object. The second lens L2, the third lens L3 having positive refractive power and both surfaces thereof are convex, the fourth lens L4 having positive refractive power, the fifth lens L5 having negative refractive power, and And a sixth lens L6 having positive refractive power and both surfaces thereof being convex, wherein each lens is provided to substantially satisfy the following conditional expression.

[Conditional expression]

는 광학계의 최대 반화각이다.Where Yd is the maximum image and f is the focal length of the optical system,

Is the maximum half angle of view of the optical system.

According to the above configuration, the conventional ultra wide-angle optical system is composed of six lenses having negative and positive power, and the refractive index distribution of each lens is negative (-), (-), (+), ( +), (-), And (+), and each lens is configured to satisfy the above conditional expression. However, the conditional expression is a conditional expression that can be easily conceived by those who have some knowledge of the field or are engaged in the field. In addition, the ultra wide-angle optical system of the above configuration does not satisfy the angle of view more than 180 degrees, and since the length of the optical system has a size of at least 14 mm or more, it is difficult to implement the ultra-wide angle, ultra-thin optical system.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above-described problems, and to provide an ultra-wide angle, ultra-thin surveillance ultra wide-angle camera lens having an angle of view of more than 190 degrees.

In addition, another technical problem to be achieved by the present invention is to provide a super wide-angle camera lens for monitoring implemented to take images of a very wide field of view using only the refractive optical system.

In addition, another technical problem to be achieved by the present invention is to provide a super-wide-angle camera lens for monitoring having a very thin angle of view of more than 190 degrees, the optical system is up to 14mm or less.

In addition, another technical problem to be achieved by the present invention is to propose a super wide-angle camera lens for monitoring the effective focal length (EFL) of the optical system is smaller than the rear focal length (BFL).

In addition, another technical problem to be achieved by the present invention is to provide a super-wide-angle camera lens for surveillance that can be applied to a camera, a camera for a vehicle, etc. mounted on a mobile communication terminal camera, a computer.

The problem of the present invention is not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

As a means for solving the above-described technical problem, the super wide-angle camera lens for monitoring according to the present invention, the first lens (L1) of the meniscus shape of which one surface is aspherical and convex toward the object side, and both surfaces are concave A second lens L2 having a shape, a third lens L3 having a meniscus shape in which one surface is aspheric and convex toward the object side, a fourth lens L4 having a convex shape on both sides, and a convex shape on both sides The fifth lens L5 and the fifth lens L5 are joined to one, and the bonded surfaces are concave and the other surface is planar, the sixth lens L6 and the third lens L3 and the third lens. A diaphragm AS is provided between the four lenses L4 and passes only the light portion necessary for the imaging, and the first to sixth lenses L1 to L6 are arranged in a straight line with respect to the optical axis.

Here, the ultra wide-angle camera lens has an angle of view of more than 190 degrees of the optical system, the effective focal length (EFL) value of the optical system is smaller than the post focal length (BFL), the optical system is preferably formed to have a maximum length of 14mm or less. Do.

The refractive indices of the first to third lenses L1 to L3 have a negative value, and the refractive indices of the fourth to sixth lenses L4 to L6 have a positive value. In this case, the refractive indices of the first to third lenses L1 to L3 have (-), (-), and (+) values, and the fourth lens L4 and the fifth and sixth lenses L5, The refractive index of L6) each has a positive value.

The ultra wide-angle camera lens has an optical filter OF between the sixth lens L6 and the imaging surface IP. In addition, the third lens L3 may be formed of a plastic material to improve processing and reduce weight as well as to reduce manufacturing cost.

According to the present invention, an optical system having an angle of view of 190 degrees or more and a very thin length of up to 14 mm or less can be photographed using only the refractive optical system, thereby capturing an image of a very wide field of view.

In addition, it is possible to significantly reduce the distortion of the image by maintaining a wide light angle while having a small light weight high quality optical performance. In addition, it has the effect of reducing the problem of deterioration at high temperature of the plastic lens through proper refractive power arrangement.

In addition, the present invention can be applied to a camera of a mobile communication terminal, a camera mounted on a computer, a car camera, and the like.

The effects of the present invention are not limited to those mentioned above, and other effects that are not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a lens configuration diagram showing a lens arrangement of an ultra wide-angle optical system according to an embodiment of the prior art.
2 is a block diagram showing the configuration of a super wide-angle camera lens for monitoring according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In order to clearly explain the present invention in the drawings, parts not related to the description are omitted, and similar parts are denoted by similar reference numerals throughout the specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Surveillance Ultra wide angle  Embodiment of the camera lens

2 is a block diagram showing the configuration of a super wide-angle camera lens for monitoring according to a preferred embodiment of the present invention. Here, the thickness, size, and shape of the lens are somewhat exaggerated for the sake of explanation, and in particular, the shape of the spherical or aspherical surface shown in the lens configuration is merely an example and is not limited thereto.

The super wide-angle camera lens for monitoring according to the present invention includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and one bonded to one, as shown in FIG. The fifth and sixth lenses L5 and L6 are disposed in a straight line with respect to the optical axis, and the aperture AS for passing only the light portion necessary for the imaging between the third lens L3 and the fourth lens L4. ) Is installed. In addition, an optical filter OF such as an infrared filter and a cover glass may be disposed between the sixth lens L6 and the imaging surface IP, and the optical filter OF may be used in optical performance. Seems to have no effect.

The first lens L1 may have a negative refractive power, and may be formed to have a meniscus shape in which one surface is aspherical and convex toward the object side. In this case, the radius of curvature of the object-side surface of the first lens (L1) is preferably larger than the radius of curvature of the image side surface.

The second lens L2 may have a negative refractive power and may be formed such that both surfaces thereof have a concave shape. In this case, the radius of curvature of the object-side surface of the second lens (L2) is preferably larger than the radius of curvature of the image side surface, but is not limited thereto, and vice versa It is also possible.

The third lens L3 may have a positive refractive power, and may be formed such that one surface has an aspherical surface and a meniscus shape convex toward the object side. At this time, the radius of curvature of each of the object-side surface and the image-side surface of the third lens L3 may be larger or smaller. The third lens L3 may be formed of a plastic material.

Preferably, the fourth lens L4 has a positive refractive power, and both surfaces thereof are formed to have a convex shape. At this time, the radius of curvature of the object-side surface of the fourth lens (L4) is preferably larger than the radius of curvature of the image side surface.

The fifth lens L5 is formed to have a convex shape on both surfaces thereof, and is bonded to the sixth lens L6 as one. In this case, the fifth and sixth lenses L5 and L6 may be separated and formed to be spaced apart by a predetermined interval.

The sixth lens L6 is bonded to the fifth lens L5 as one, and is preferably formed such that the joined surface is formed to have a concave shape and the other surface is formed to have a flat plane shape. Preferably, the fifth and sixth lenses L5 and L6 joined to one have positive refractive power.

In addition, the aperture AS may be provided between the third lens L3 and the fourth lens L4 so as to pass only a light beam portion necessary for imaging.

Meanwhile, at least one of both surfaces of at least one of the first lens L1 and the third lens L3 may be aspheric.

As described above, by arranging the lens according to the refractive power of each lens and including the aspherical surface, the correction of various aberrations can be facilitated, and the optical characteristics can be further improved. That is, by properly arranging the lenses having negative refractive power and the lenses having positive refractive power, chromatic aberration can be corrected and high resolution can be realized. Particularly, the first lens L1 and the third lens can be realized. When L3 is used as an aspherical lens, it is possible to reduce various aberrations such as spherical aberration while improving the resolution of the lens, and to realize a compact and excellent optical system.

In addition, when some lenses include an aspherical refractive surface, the aspherical lens is preferably formed of a plastic material for ease of aspherical surface fabrication. Thus, in the embodiment of the present invention, the third lens L3 is formed of a plastic material.

As described above, when the plastic lens is adopted, not only the processing and weight reduction but also the manufacturing cost can be reduced.

Further, the first lens L1 and the second lens L2 having negative refractive power, and the third lens L3 having positive refractive power, respectively, are sequentially disposed, and each positive (+) The fourth lens L4 and the fifth and sixth lenses L5 and L6 having the refractive power of () are sequentially arranged, and the meniscus shape and the aspherical surface are appropriately formed to properly refract the light incident through a wide field of view. The distortion of the image can be minimized as much as possible.

The ultra-wide-angle camera lens for monitoring of the present invention configured as described above can solve the technical problem of the present invention by configuring an optical system having an angle of view of 190 degrees or more and a very thin length of 14 mm or less using only a refractive optical system.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Further, the features, structures, effects and the like illustrated in the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong.

Therefore, it should be understood that the present invention is not limited to these combinations and modifications. In addition, the above description has been made with reference to the embodiments, which are merely examples and are not intended to limit the present invention, and those skilled in the art to which the present invention pertains may be illustrated in the above without departing from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

L1: first lens L2: second lens
L3: third lens L4: fourth lens
L5: fifth lens L6: sixth lens
AS: Aperture OF: Optical Filter
IP: Image plane

Claims (8)

A first lens L1 having a meniscus shape in which one surface is aspherical and convex toward the object side;
A second lens L2 having a concave shape on both surfaces thereof;
A third lens L3 having a meniscus shape in which one surface is aspherical and convex toward the object side;
A fourth lens L4 of which both surfaces are convex;
A fifth lens L5 of which both surfaces are convex;
A sixth lens L6 bonded to the fifth lens L5 and having a concave shape, and the other surface thereof being planar; And
Included between the third lens (L3) and the fourth lens (L4), the aperture (AS) for passing only the light portion necessary for the imaging; includes,
The super wide-angle camera lens for monitoring, wherein the first to sixth lenses (L1 to L6) are disposed in a straight line with respect to the optical axis.
The method of claim 1, wherein the ultra wide-angle camera lens is:
Ultra wide-angle camera lens with an optical angle of view of more than 190 degrees.
The method of claim 1, wherein the ultra wide-angle camera lens is:
Ultra wide-angle camera lens with an effective focal length (EFL) of the optics less than the rear focal length (BFL).
The method of claim 1,
The refractive indices of the first to third lenses L1 to L3 have a negative value,
The refractive index of the fourth to sixth lenses L4 to L6 has a positive value.
The method of claim 1,
The refractive index of the first lens L1 has a negative value,
The refractive index of the second lens L2 has a negative value,
The refractive index of the third lens L3 has a positive value,
The refractive index of the fourth lens L4 has a positive value,
The refractive index of the fifth and sixth lenses (L5, L6) has a positive (+) value of the wide-angle camera lens.
The method of claim 1, wherein the ultra wide-angle camera lens is:
Ultra wide-angle camera lens with optical system up to 14mm in length.
The method of claim 1, wherein the ultra wide-angle camera lens is:
An ultra wide-angle camera lens provided with an optical filter (OF) between the sixth lens (L6) and the imaging surface (IP).
The method of claim 1, wherein the third lens (L3) is:
Ultra wide-angle camera lens made of plastic.

Images