WO2016195137A1

WO2016195137A1 - Fisheye lens and imaging device

Info

Publication number: WO2016195137A1
Application number: PCT/KR2015/005627
Authority: WO
Inventors: 최영삼; 지삼현
Original assignee: 하이네트(주)
Priority date: 2015-06-04
Filing date: 2015-06-04
Publication date: 2016-12-08
Also published as: KR20160143170A

Abstract

The present invention relates to a fisheye lens and an imaging device that comprise: a first lens (L1) having a biconvex shape in which the object side and the upper surface thereof are convex and have the same radius of curvature; a second lens (L2) having a biconcave shape in which the opposite surfaces thereof are concave, and the object side thereof has a radius of curvature that is larger than that of the upper side thereof; a third lens (L3) having a biconvex shape in which one surface thereof is an aspheric surface, and the object side and the upper side thereof are convex; a fourth lens (L4) in which the upper side thereof is convex, and the other surface thereof is planar; a fifth lens (L5) in which the opposite surfaces thereof are convex; a sixth lens (L6) in which the object side thereof is convex, and the other surface thereof is planar; an aperture that is configured between the third lens (L3) and the fourth lens (L4) and passes only the rays of light required for image formation; and an optical filter between the sixth lens (L6) and the image formation surface.

Description

Fisheye Lens and Imager

The present invention relates to a fisheye lens and an imaging device.

The fisheye lens is an optical system that mimics the function of the human eye, and has an extremely wide field of view and high optical power when focused on the center of the field of view.

Such an optical system is described in Korean Patent Publication No. 10-0932850 (published date: December 10, 2009, name of the invention: fisheye lens).

Various proposals are known for the optical system for implementing fisheye lenses.

The multiple optical system, which combines a telephoto lens with a narrow angle of view and a wide-angle lens, has a problem in that the complexity and size of the system is difficult. Even if it is realized by a binocular optical system, in this case, parallax with a subject Is a problem.

As an alternative, the use of a zoom lens can be considered, but it is difficult to simultaneously satisfy a wide field of view and high resolution.

There is a drawback that only one time can be confirmed at any moment and time due to zooming.

As another method, a reflection refraction optical system has been proposed. However, in the reflection refraction optical system, the central portion, which is the center point of the field of view, becomes a blind spot, so that the entire area cannot be observed with the donut fisheye lens.

Recently, a method of solving the blind spot in the center using a wide-angle optical system has emerged.

This optical system is a lens which generates distortion of a barrel shape of negative shape as the distortion distortion of an image becomes small and becomes a circumferential edge in the center of the field of view.

However, such a lens is also difficult to widen the field of view up to about 180 degrees, and the distortion is prioritized, so that the resolution is partially insufficient, or another important characteristic of the eye, that is, very uniform to the periphery of the field of view, or There is a problem in that it is impossible to have a more sensitive sensitivity and the surroundings become darker, resulting in a lens that is substantially narrower in view.

According to an aspect of the present invention, a fisheye lens and an image pickup device include at least three biconvex lenses having both positive and positive refractive powers, and concave lenses at both object and image sides. At least one biconcave lens that is composed and has a negative refractive power, Plano convex lens with the flat side facing the object side and the convex side facing the upper side, the convex side facing the subject side, and the flat face the upper side Plano convex lens and image sensor directed to the.

According to this feature, it is possible to obtain a fisheye lens with a low distortion while obtaining an image of the full azimuth.

In addition, it can be miniaturized and is easy to install and can be implemented at low cost.

1 is a block diagram of a fisheye lens and an imaging system according to an 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 the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Next, a fisheye lens light imaging apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

First, a fisheye lens and an imaging device according to an embodiment of the present invention will be described in detail with reference to FIG. 1.

Referring to FIG. 1, in the fisheye lens and the image capturing apparatus according to the embodiment of the present invention, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are linearly aligned with respect to the optical axis. A first lens L1 having a convex lens on both the object side and the image side, a second lens L2 having a negative refractive power, and an object side on both the object side and the image side A third lens L3 composed of both convex lenses and an image side, a fourth lens L4 having a flat surface facing the object side and a convex surface facing the image side, and a fifth lens having both the object side and the image side convex The lens L5 and the sixth lens L6 having the convex surface facing the object side and the flat surface facing the image side are included. An aperture stop (not shown) is provided between the third lens L3 and the fourth lens L4 to allow only a light portion necessary for an image to pass through. An optical filter (not shown) such as an infrared cut filter and a cover glass is preferably provided between the sixth lens L6 and the image surface (image forming surface). In addition, an image sensor is installed on the imaging surface to convert an image of the light incident through the lens into an electrical signal to acquire an image.

The first lens L1 has a positive refractive power and preferably has the same radius of curvature at the object side and the image side.

The second lens L2 may have a negative refractive power and both surfaces thereof may have a concave shape, and the curvature radius of the object side may be larger than the curvature radius of the image side.

The third lens L3 has a positive refractive power and has a convex shape on both sides thereof, and each radius of curvature of the object side or the image side is the same and may be formed of a plastic material.

The fourth lens L4 may have a positive refractive power and have an object-side convex shape.

The fifth lens L5 has a positive refractive power and a convex shape on both sides thereof, and each radius of curvature of the object side or the image side is the same and may be formed of a plastic material.

The sixth lens L6 may have a positive refractive power and have an image-side convex shape.

In addition, between the third lens L3 and the fourth lens L4, an aperture (not shown) for passing only light necessary for imaging is preferably located.

As described above, a lens having positive refractive power and negative refractive power may be disposed to correct chromatic aberration, and some lenses may include aspherical surfaces to increase resolution.

When the third lens L3 is aspheric, resolution of the lens may be improved and various aberrations including spherical aberration may be reduced.

If some lenses are aspherical, it is not possible to process with glass material, so it is preferable to configure the plastic material with excellent workability.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims

A first lens L1 having a Biconvex shape having a convex object surface and an image surface having the same curvature radius,

A second lens L2 having a biconcave shape in which both surfaces are concave and the curvature on the object side is larger than the curvature on the image side;

A third lens L3 having a biconvex shape in which one surface is aspherical and the object side and the image side are convex;

An image side is convex and the other side is a planar fourth lens L4,

The fifth lens L5 having a convex shape on both sides thereof,

The sixth lens L6 of which the object side is convex and the other surface is planar;

An aperture disposed between the third lens L3 and the fourth lens L4 and allowing only a light ray portion necessary for imaging to pass therethrough.

Fisheye lens and imaging device comprising a.
In claim 1,

A fisheye lens and imaging device comprising an optical filter between a sixth lens (L6) and an imaging surface.