KR100959165B1 - compact imaging lens - Google Patents

Abstract

The present invention relates to an ultra-wide-angle lens, comprising a first lens member that is convex in the image direction and has a positive refractive power, and is disposed at a predetermined interval in an image direction of the first lens member, and is adjacent to the first lens member. A portion of the surface and a surface formed in the image direction includes a second lens member having a convex shape in the image direction. And an aperture positioned between the first lens member and the second lens member to determine brightness of the lens, the aperture being spaced a predetermined distance in the image direction of the second lens member, and both sides of the lens having a bent portion. And a third lens member.

According to the present invention, the optical configuration uses a wide-angle lens forming a PPP, and at least two or more aspherical surfaces satisfy a 170 degree angle of view while satisfying the ultra-small size, and accordingly, the medical optical device or the camera for front and rear view cameras and the like. Likewise, ultra-wide angle lenses can be used where needed.

Refractive power, wide-angle lens, angle of view, tiny

Description

Compact wide-angle lens

The present invention relates to an ultra-small wide-angle lens having a wide angle of view of 170 degrees within 2.5mm to 3.5mm length and used in solid-state imaging devices of digital input devices, such as medical optical equipment and surveillance cameras.

In recent years, the spread of electronic still cameras and video cameras using CCDs and solid-state image pickup devices has been rapidly expanding, and have become smaller, lighter, and cheaper.

With such miniaturization, the use of small cameras such as mobile cameras and web cameras is increasing, and along with the miniaturization of cameras, compact weight reduction and low cost are strongly required for the imaging optical system embedded in the camera.

In particular, many optical lenses, which are one of the imaging optical systems for solid-state imaging devices used for surveillance cameras, cameras mounted on automobiles, and the like, have been proposed in the past, and among them, optical lenses having an imaging area of about 150 degrees in total are used.

However, the conventional optical lens is composed of at least eight lens members while the first lens group, the diaphragm, and the second lens group are arranged in sequence, resulting in a long overall length and a complicated configuration thereof. In addition, as having more than eight lens members, manufacturing difficulties in terms of cost and weight.

Accordingly, there is an increasing need for a small optical lens that provides a wide overall angle of view with a small number of lens members and is inexpensive and light.

The present invention is to reduce the overall length of the wide-angle lens by using three lens members in order to solve the conventional problems as described above, and to reduce the size, all the lens members have a PPP optical configuration showing a positive refractive power to achieve a resolution of VGA or higher It is an object of the present invention to provide an ultra-small wide-angle lens having.

In order to achieve the above object, in the ultra-wide-angle lens of the present invention, three lens members having positive refractive power are used to satisfy a wide angle of view of 170 degrees and have VGA-class optical performance.

The ultra-wide-angle lens of the present invention, from the object side, the first lens member having positive refractive power and convex in the image direction, the second lens member having positive refractive power and convex in the image direction, and It includes a third lens member having a refractive power, both sides of the lens having a bent portion.

Preferably, at least two or more lens members of the first, second and third lens members are composed of aspherical lenses.

In the present invention, the length of the wide-angle lens is preferably 2.5mm to 3.5mm.

In the present invention, the angle of view of the wide-angle lens is preferably 130 degrees to 170 degrees diagonally.

According to the present invention, by configuring a wide-angle lens using three lens members having positive refractive power, there is an effect that can be used in various sizes such as medical optical devices and camera optical systems in a very small size.

In addition, since the P-P-P optical structure (all three lens members exhibit positive refractive power) has a wide viewing angle of 170 degrees and a resolution of VGA or more, optical performance is improved.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings. In adding reference numerals to components of the following drawings, it is determined that the same components have the same reference numerals as much as possible even if displayed on different drawings, and it is determined that they may unnecessarily obscure the subject matter of the present invention. Detailed descriptions of well-known functions and configurations will be omitted.

1 is a cross-sectional view illustrating a micro wide-angle lens according to an embodiment of the present invention.

Referring to FIG. 1, a first lens member 100, a second lens member 110, an aperture 120, a third lens member 130, an imaging surface 140, and an optical member 150 are included.

The first lens member 100 is formed closest to the object side when the optical lens is configured, is convex in the image direction, and has a positive refractive power for the light incident by the object and has the second lens member ( To 110).

The second lens member 110 is formed to be spaced apart a predetermined interval in the image direction of the first lens member 100, and has a positive refractive power (positive refractive power) to receive the light incident from the first lens member 100 Transfer to the third lens member 120.

The second lens member 110 is convex in the image direction, and the convex portions are symmetrically formed up and down from the horizontal central axis of the second lens member 110.

The aperture 120 is positioned between the first lens member 100 and the second lens member 110 to adjust the brightness of the lens. In addition, when the diaphragm 120 is positioned adjacent to the first lens member 100, the diaphragm 120 may be excessively large, and distortion aberration may deteriorate. It is preferable to position adjacent to the two lens member (110).

The third lens member 120 is formed to be spaced apart by a predetermined interval in the image direction of the second lens member 110, and has a positive refractive power (positive refractive power) to receive the light incident from the second lens member 110 It transfers to the optical member 130 via the imaging surface 120.

In addition, both surfaces of the third lens member 130 may form an inflection portion, thereby acting as aberration performance correction for axle aberration.

The first lens member 100, the second lens member 110, and the third lens member 120 may be formed of glass or plastic, and at least two or more of the three lens members may be formed as an aspherical surface. The efficiency of the lens can be improved.

The optical member 130 has a surface that does not have a refractive power of light is disposed on the optical path, it is possible to block the infrared light incident on the image pickup device by applying an infrared control coating.

When the optical member 130 is not used, an infrared control coating is applied to one of the three lens members (first, second and third lens members), or the lens material itself absorbs infrared rays. It is possible to minimize the incidence of infrared rays to the imaging device by constructing a material that can be used.

2A to 2B are graphs illustrating the performance measured by designing a micro-wide lens according to an embodiment of the present invention, and show data obtained by designing the micro-wide lens according to Table 1 below.

Lens member Focal length One 10.504084 2 1.643044 3 42.677795 Lens Overall Length = 3.26mm

Table 2 above shows design data of the wide-angle lens of FIGS. 2A to 2B.

Through the contents of the present invention according to the above 1 to 2b it can be seen that the efficiency of the ultra-wide angle lens composed of three lens members is improved compared to the conventional optical lens composed of more than eight lens members. .

In the present invention, the overall length of the wide-angle lens within 2.5mm to 3.5mm can be used in various applications such as wide-angle lens module for camera phones, surveillance cameras, medical optical devices such as endoscopes and optical systems for automobile front and rear cameras.

In addition, in the wide-angle lens of the present invention, as all three lens members have positive refractive power, the entire angle of view may satisfy the range of 130 degrees to 170 degrees (see FIG. 3). By having a resolution, it is possible to implement a wide-angle lens having excellent microscopic optical performance.

As described above, it has been described with reference to a preferred embodiment of the present invention, but those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

1 is a cross-sectional view showing a miniature wide-angle lens according to an embodiment of the present invention.

2A to 3B are graphs illustrating the performance measured by designing a miniature wide-angle lens according to an embodiment of the present invention.

3 is a cross-sectional view showing the angle of view of the ultra-wide angle lens applied to the medical optical device according to an embodiment of the present invention.

         <Explanation of symbols for the main parts of the drawings>

100: first lens member 110: second lens member

120: aperture 130: third lens member

140: imaging surface 150: optical member

Claims (4)

Sequentially from the object side, A first lens member having positive refractive power and convex in the image direction; A second lens member having positive refractive power and convex in the image direction; An ultra-small wide-angle lens having a positive refractive power and including a third lens member having both sides of the lens with a bent portion. The method of claim 1, At least two or more lens members of the first, second, and third lens members are composed of aspherical lenses. The method of claim 1, The ultra wide-angle lens, characterized in that the length of the wide angle lens is 2.5mm ~ 3.5mm. The method of claim 1, The ultra-wide angle lens of claim 1, wherein the angle of view of the wide-angle lens is 130 degrees to 170 degrees at a diagonal.

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