TW201814346A - Optical lens system with a wide field of view - Google Patents

Abstract

An optical lens system with a wide field of view includes, in order from the object side to the image side: an aperture stop; a first lens element with a negative refractive power; a second lens element with a positive refractive power; a third lens element with a negative refractive power; a fourth lens element with a positive refractive power; a fifth lens element with a negative refractive power, so that the optical lens system has a wide field of view, high resolution, short length and less distortion.

Description

Wide-angle lens group

The present invention relates to a wide-angle lens group, and more particularly to a miniaturized five-piece wide-angle lens group for use in electronic products.

With the rise of electronic products with photographic functions, the demand for optical systems is increasing. In the shooting, in order to obtain a wider shooting range, the angle of view of the lens is required to meet certain requirements, and thus the requirements for the angle and quality of the lens are becoming stricter. Usually, the angle of the lens (the field of view FOV) is designed to be 50 to 60 degrees. If the angle of the above design is exceeded, not only the aberration is large, but also the design of the lens is complicated. Conventional US 8335043, US 8576497 use 2 lens groups, 5-6 pieces to achieve a large angle purpose, but its distortion is too large, and such as US 8593737, US 8576497, US 8395853, although it can achieve a large angle purpose, However, the total length (TL) of the lens group is too long.

Therefore, how to develop a miniaturized wide-angle lens group, which can be equipped with a lens for a digital camera, a lens for a network camera, or a mobile phone lens, etc., and has a larger angle of view and a reduced image. The poor efficacy to reduce the complexity of the lens design is the motivation for the development of the present invention.

The object of the present invention is to provide a wide-angle lens group, in particular to a five-piece wide-angle lens group which has an improved drawing angle, high resolution, short lens length and small distortion.

In order to achieve the foregoing objective, a wide-angle lens group according to the present invention includes, in order from the object side to the image side, an aperture; a first lens having a negative refractive power and a near-optical axis of the object side surface; The convex surface has a concave surface at the near-optical axis of the image side surface, and at least one surface of the object side surface and the image side surface is aspherical; a second lens has a positive refractive power, and the object side surface has a convex surface at a near optical axis. The image side surface of the image has a convex surface, and at least one surface of the object side surface and the image side surface is aspherical; a third lens has a negative refractive power, and the image side surface is concave at the near optical axis, and the object side thereof At least one surface of the surface and the image side surface is aspherical; a fourth lens has a positive refractive power, and the object side surface is convex at the near optical axis, and the image side surface is convex at the near optical axis, and the object side surface and image thereof At least one surface of the side surface is aspherical; a fifth lens has a negative refractive power, and the object side surface is convex at the near optical axis, and the image side surface is concave at the near optical axis, and the object side surface and the image side surface are at least a surface is aspherical, its object side surface and image Surface of at least one surface having at least one inflection point.

Preferably, wherein the focal length of the first lens is f1, the focal length of the second lens is f2, and the following condition is satisfied: -2.4 < f1/f2 < -0.8. Thereby, the refractive power arrangement of the first lens and the second lens is suitable, which is advantageous for obtaining a wide angle of view (angle of view) and reducing excessive increase of system aberration.

Preferably, wherein the focal length of the second lens is f2, the focal length of the third lens is f3, and the following condition is satisfied: -1.1 < f2/f3 < -0.6. Thereby, the arrangement of the refractive power of the second lens and the third lens is balanced, which contributes to the correction of the aberration and the reduction of the sensitivity.

Preferably, wherein the third lens has a focal length of f3, the fourth lens has a focal length of f4, and satisfies the following condition: -1.8 < f3/f4 < -0.5. Thereby, it is advantageous to ensure a negative-positive telephoto structure formed by the third lens and the fourth lens, which can effectively reduce the total optical length of the system.

Preferably, wherein the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, and the following condition is satisfied: -0.8 < f4/f5 < -0.05. Thereby, the refractive power arrangement of the rear group lens system can be balanced, which is beneficial to the reduction of system sensitivity and the correction of high-order aberrations.

Preferably, wherein the focal length of the first lens is f1, the focal length of the third lens is f3, and the following condition is satisfied: 0.7 < f1/f3 < 2.0. Thereby, the refractive power of the first lens is effectively distributed, and the sensitivity of the wide-angle lens group is reduced.

Preferably, wherein the focal length of the second lens is f2, the focal length of the fourth lens is f4, and the following condition is satisfied: 0.3 < f2 / f4 < 1.5. Therefore, the system's negative refractive power distribution is more suitable, which is beneficial to correct system aberrations to improve the imaging quality of the system.

Preferably, wherein the focal length of the third lens is f3, the focal length of the fifth lens is f5, and the following condition is satisfied: 0.05 < f3 / f5 < 1.0. Thereby, it contributes to shortening the total length of the wide-angle lens group and maintaining the miniaturization thereof.

Preferably, wherein the focal length of the first lens is f1, the combined focal length of the second lens and the third lens is f23, and the following condition is satisfied: -1.3 < f1/f23 < -0.25. Thereby, when f1/f23 satisfies the above conditions, the wide-angle lens group can significantly improve the resolution of the image while obtaining a wide angle of view (angle of view).

Preferably, wherein the combined focal length of the second lens and the third lens is f23, the combined focal length of the fourth lens and the fifth lens is f45, and the following condition is satisfied: 0.6 <f23/f45 < 3.6. When f23/f45 satisfies the foregoing relationship, the wide-angle lens group can have a large picture angle, a high number of pictures, and a low lens height, and the resolution capability is remarkably improved. Conversely, if the optical data value range is exceeded, This can cause problems in the performance, low resolution, and insufficient yield of the wide-angle lens group.

Preferably, wherein the combined focal length of the first lens and the second lens is f12, the combined focal length of the third lens and the fourth lens is f34, and the following condition is satisfied: -0.1 < f12/f34 < 0.8. Thereby, it is advantageous to obtain a wide angle of view (angle of view) and to effectively correct the curvature of field.

Preferably, wherein the combined focal length of the third lens and the fourth lens is f34, the focal length of the fifth lens is f5, and the following condition is satisfied: -2.3 < f34/f5 < 6.8. When f34/f5 satisfies the foregoing relationship, the wide-angle lens group can have a large picture angle, a high number of pictures, and a low lens height, and the resolution capability is remarkably improved. Conversely, if the optical data value range is exceeded, This can cause problems in the performance, low resolution, and insufficient yield of the wide-angle lens group.

Preferably, wherein the focal length of the first lens is f1, the combined focal length of the second lens, the third lens and the fourth lens is f234, and the following condition is satisfied: -2.2 < f1/f234 < -0.5. By proper configuration of the refractive power, it helps to reduce the occurrence of spherical aberration and astigmatism.

Preferably, wherein the second lens, the third lens and the fourth lens have a combined focal length of f234, the fifth lens has a focal length of f5, and satisfies the following condition: -0.9 < f234/f5 < -0.05. By proper configuration of the refractive power, it helps to reduce the occurrence of spherical aberration and astigmatism.

Preferably, wherein the first lens, the second lens and the third lens have a combined focal length of f123, the fourth lens has a focal length of f4, and satisfies the following condition: -4.9 < f123/f4 < 4.5. By proper configuration of the refractive power, it helps to reduce the occurrence of spherical aberration and astigmatism.

Preferably, wherein the first lens, the second lens and the third lens have a combined focal length of f123, the fourth lens and the fifth lens have a combined focal length of f45, and satisfy the following condition: -5.1< f123/f45 < 3.5 . By proper configuration of the refractive power, it helps to reduce the occurrence of spherical aberration and astigmatism.

Preferably, wherein the focal length of the first lens is f1, the combined focal length of the second lens, the third lens, the fourth lens and the fifth lens is f2345, and the following condition is satisfied: -2.5 < f1/f2345 < -1.2 . Therefore, when f1/f2345 satisfies the foregoing relationship, the wide-angle lens group can have a large picture angle, and the image resolution capability is remarkably improved. On the contrary, if the optical data value range is exceeded, the wide-angle lens is caused. Group performance, low resolution, and insufficient yield.

Preferably, wherein the second lens has a dispersion coefficient of V2, the third lens has a dispersion coefficient of V3, and satisfies the following condition: 29 < V2-V3 < 42. Thereby, the chromatic aberration of the wide-angle lens group is effectively reduced.

Preferably, wherein the fourth lens has a dispersion coefficient of V4, the fifth lens has a dispersion coefficient of V5, and satisfies the following condition: 29 < V4-V5<42. Thereby, the chromatic aberration of the wide-angle lens group is effectively reduced.

Preferably, wherein the overall focal length of the wide-angle lens group is f, the distance from the object side surface of the first lens to the imaging surface on the optical axis is TL, and the following condition is satisfied: 0.05 < f / TL < 0.4. Thereby, it is advantageous to obtain a wide angle of view (angle of view) and to facilitate the miniaturization of the wide-angle lens group to be mounted on a thin electronic product.

With regard to the techniques, means, and other effects of the present invention in order to achieve the above objects, three preferred embodiments are described in detail with reference to the drawings.

<First Embodiment>

1A and FIG. 1B, FIG. 1A is a schematic diagram of a wide-angle lens group according to a first embodiment of the present invention, and FIG. 1B is a left-to-right image plane curvature and distortion of the wide-angle lens group of the first embodiment. The difference graph. As shown in FIG. 1A, the wide-angle lens assembly includes an aperture 100 and an optical group. The optical group sequentially includes a first lens 110, a second lens 120, a third lens 130, and a fourth lens 140 from the object side to the image side. The fifth lens 150, the infrared filter element 170, and the imaging surface 180, wherein the lens having the refractive power in the wide-angle lens group is five pieces. The aperture 100 is disposed between the image side surface 112 of the first lens 110 and the image side surface 122 of the second lens 120.

The first lens 110 has a negative refractive power and is made of a plastic material. The object side surface 111 is convex at the near optical axis 190, and the image side surface 112 is concave at the near optical axis 190, and the object side surface 111 and the image side are Surface 112 is aspherical.

The second lens 120 has a positive refractive power and is made of a plastic material. The object side surface 121 is convex at the near optical axis 190, and the image side surface 122 is convex at the near optical axis 190, and the object side surface 121 and the image side are Surface 122 is aspherical.

The third lens 130 has a negative refractive power and is made of a plastic material. The object side surface 131 is concave at the near optical axis 190, and the image side surface 132 is concave at the near optical axis 190, and the object side surface 131 and the image side are The surfaces 132 are all aspherical.

The fourth lens 140 has a positive refractive power and is made of a plastic material. The object side surface 141 is convex at the near optical axis 190, and the image side surface 142 is convex at the near optical axis 190, and the object side surface 141 and the image side are Surfaces 142 are all aspherical.

The fifth lens 150 has a negative refractive power and is made of a plastic material, and the object side surface 151 is convex at the near optical axis 190, and the image side surface 152 is concave at the near optical axis 190, and the object side surface 151 and the image side are The surface 152 is aspherical, and at least one surface of the object side surface 151 and the image side surface 152 has at least one inflection point.

The infrared filter element 170 is made of glass and is disposed between the fifth lens 150 and the imaging surface 180 without affecting the focal length of the wide-angle lens group.

The aspherical curve equations of the above lenses are expressed as follows:

Where z is the position value with reference to the surface apex at a position of height h in the direction of the optical axis 190; c is the curvature of the lens surface near the optical axis 190, and is the reciprocal of the radius of curvature (R) (c = 1/R) R is the radius of curvature of the lens surface near the optical axis 190, h is the vertical distance of the lens surface from the optical axis 190, k is a conic constant, and A, B, C, D, E, G, ... are High order aspheric coefficient.

In the wide-angle lens group of the first embodiment, the focal length of the wide-angle lens group is f, the aperture value (f-number) of the wide-angle lens group is Fno, and the maximum angle of view (arrow angle) in the wide-angle lens group is FOV, and the values are as follows :f=1.12 (mm); Fno=2.4; and FOV=111 (degrees).

In the wide-angle lens group of the first embodiment, the focal length of the first lens 110 is f1, the focal length of the second lens 120 is f2, and the following condition is satisfied: f1/f2 = -1.77.

In the wide-angle lens group of the first embodiment, the focal length of the second lens 120 is f2, the focal length of the third lens 130 is f3, and the following condition is satisfied: f2/f3 = -0.82.

In the wide-angle lens group of the first embodiment, the focal length of the third lens 130 is f3, the focal length of the fourth lens 140 is f4, and the following condition is satisfied: f3/f4 = -0.70.

In the wide-angle lens group of the first embodiment, the focal length of the fourth lens 140 is f4, the focal length of the fifth lens 150 is f5, and the following condition is satisfied: f4/f5 = -0.49.

In the wide-angle lens group of the first embodiment, the focal length of the first lens 110 is f1, the focal length of the third lens 130 is f3, and the following condition is satisfied: f1/f3 = 1.45.

In the wide-angle lens group of the first embodiment, the focal length of the second lens 120 is f2, the focal length of the fourth lens 140 is f4, and the following condition is satisfied: f2/f4 = 0.58.

In the wide-angle lens group of the first embodiment, the focal length of the third lens 130 is f3, the focal length of the fifth lens 150 is f5, and the following condition is satisfied: f3/f5 = 0.34.

In the wide-angle lens group of the first embodiment, the focal length of the first lens 110 is f1, the combined focal length of the second lens 120 and the third lens 130 is f23, and the following condition is satisfied: f1/f23 = -0.90.

In the wide-angle lens group of the first embodiment, the combined focal length of the second lens 120 and the third lens 130 is f23, and the combined focal length of the fourth lens 140 and the fifth lens 150 is f45, and the following conditions are satisfied: f23/f45 = 0.88.

In the wide-angle lens group of the first embodiment, the composite focal length of the first lens 110 and the second lens 120 is f12, and the combined focal length of the third lens 130 and the fourth lens 140 is f34, and the following conditions are satisfied: f12/f34 = -0.03.

In the wide-angle lens group of the first embodiment, the combined focal length of the third lens 130 and the fourth lens 140 is f34, and the focal length of the fifth lens 150 is f5, and the following condition is satisfied: f34/f5 = 6.47.

In the wide-angle lens group of the first embodiment, the focal length of the first lens is f1, and the combined focal length of the second lens 120, the third lens 130, and the fourth lens 140 is f234, and the following conditions are satisfied: f1/f234 = - 1.30.

In the wide-angle lens group of the first embodiment, the combined focal length of the second lens 120, the third lens 130, and the fourth lens 140 is f234, and the focal length of the fifth lens 150 is f5, and the following conditions are satisfied: f234/f5 = -0.38.

In the wide-angle lens group of the first embodiment, the combined focal length of the first lens 110, the second lens 120, and the third lens 130 is f123, and the focal length of the fourth lens 140 is f4, and the following conditions are satisfied: f123/f4 = 1.75.

In the wide-angle lens group of the first embodiment, the composite focal length of the first lens 110, the second lens 120, and the third lens 130 is f123, and the combined focal length of the fourth lens 140 and the fifth lens 150 is f45, and the following is satisfied. Condition: f123/f45 = 1.35.

In the wide-angle lens group of the first embodiment, the focal length of the first lens 110 is f1, and the combined focal length of the first lens 110, the second lens 120, the third lens 130, and the fourth lens 140 is f1234, and the following conditions are met. : f1/f2345 = -1.44.

In the wide-angle lens group of the first embodiment, the second lens 120 has a dispersion coefficient of V2, and the third lens 130 has a dispersion coefficient of V3 and satisfies the following condition: V2-V3 = 33.60.

In the wide-angle lens group of the first embodiment, the fourth lens 140 has a dispersion coefficient of V4, and the fifth lens 150 has a dispersion coefficient of V5 and satisfies the following condition: V4-V5 = 33.60.

In the wide-angle lens group of the first embodiment, the overall focal length of the wide-angle lens group is f, the distance from the object-side surface 111 to the imaging surface 180 of the first lens 110 on the optical axis 190 is TL, and the following conditions are satisfied: f /TL = 0.6571.

Refer to Table 1 and Table 2 below for reference.

Table 1 is the detailed structural data of the first embodiment of Fig. 1A, in which the unit of curvature radius, thickness and focal length is mm, and the surfaces 0-15 sequentially represent the surface from the object side to the image side. Table 2 is the aspherical data in the first embodiment, wherein the cone coefficients in the a-spherical curve equation of k, A, B, C, D, E, F, G, ... are high-order aspheric coefficients. In addition, the following table of the embodiments corresponds to the schematic diagram and the field curvature curve of each embodiment, and the definition of the data in the table is the same as the definitions of Table 1 and Table 2 of the first embodiment, and details are not described herein.

<Second embodiment>

2A and 2B, wherein FIG. 2A is a schematic diagram of a wide-angle lens group according to a second embodiment of the present invention, and FIG. 2B is a left-to-right sequential curvature and distortion of the wide-angle lens group of the second embodiment. The difference graph. As can be seen from FIG. 2A, the wide-angle lens assembly includes an aperture 200 and an optical group. The optical group includes a first lens 210, a second lens 220, a third lens 230, and a fourth lens 240 from the object side to the image side. The fifth lens 250, the infrared filter element 270, and the imaging surface 280, wherein the lens having the refractive power in the wide-angle lens group is five pieces. The aperture 200 is disposed between the image side surface 212 of the first lens 210 and the image side surface 222 of the second lens 220.

The first lens 210 has a negative refractive power and is made of a plastic material. The object side surface 211 is convex at the near optical axis 290, and the image side surface 212 is concave at the near optical axis 290, and the object side surface 211 and the image side are Surface 212 is aspherical.

The second lens 220 has a positive refractive power and is made of a plastic material. The object side surface 221 is convex at the near optical axis 290, and the image side surface 222 is convex at the near optical axis 290, and the object side surface 221 and the image side are Surfaces 222 are all aspherical.

The third lens 230 has a negative refractive power and is made of a plastic material. The object side surface 231 is convex at the near optical axis 290, and the image side surface 232 is concave at the near optical axis 290, and the object side surface 231 and the image side are Surfaces 232 are all aspherical.

The fourth lens 240 has a positive refractive power and is made of a plastic material. The object side surface 241 is convex at the near optical axis 290, and the image side surface 242 is convex at the near optical axis 290, and the object side surface 241 and the image side are Surface 242 is aspherical.

The fifth lens 250 has a negative refractive power and is made of a plastic material. The object side surface 251 is convex at the near optical axis 290, and the image side surface 252 is concave at the near optical axis 290, and the object side surface 251 and the image side are The surface 252 is aspherical, and at least one surface of the object side surface 251 and the image side surface 252 has at least one inflection point.

The infrared filter element 270 is made of glass and disposed between the fifth lens 250 and the imaging surface 280 without affecting the focal length of the wide-angle lens group.

Refer to Table 3 and Table 4 below.

In the second embodiment, the aspherical curve equation represents the form as in the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and are not described herein.

With Table 3 and Table 4, the following data can be derived:

<Third embodiment>

Please refer to FIG. 3A and FIG. 3B , wherein FIG. 3A is a schematic diagram of a wide-angle lens group according to a third embodiment of the present invention, and FIG. 3B is a left-to-right sequential image curvature and distortion of the wide-angle lens group of the third embodiment. The difference graph. As can be seen from FIG. 3A, the wide-angle lens assembly includes an aperture 300 and an optical group. The optical group sequentially includes a first lens 310, a second lens 320, a third lens 330, and a fourth lens 340 from the object side to the image side. The fifth lens 350, the infrared filter element 370, and the imaging surface 380, wherein the lens having the refractive power in the wide-angle lens group is five pieces. The aperture 300 is disposed between the image side surface 312 of the first lens 310 and the image side surface 322 of the second lens 320.

The first lens 310 has a negative refractive power and is made of a plastic material. The object side surface 311 is convex at the near optical axis 390, and the image side surface 312 is concave at the near optical axis 390, and the object side surface 311 and the image side are Surfaces 312 are all aspherical.

The second lens 320 has a positive refractive power and is made of a plastic material. The object side surface 321 is convex at the near optical axis 390, and the image side surface 322 is convex at the near optical axis 390, and the object side surface 321 and the image side are Surfaces 322 are all aspherical.

The third lens 330 has a negative refractive power and is made of a plastic material. The object side surface 331 is convex at the near optical axis 390, and the image side surface 332 is concave at the near optical axis 390, and the object side surface 331 and the image side are Surface 332 is aspherical.

The fourth lens 340 has a positive refractive power and is made of a plastic material. The object side surface 341 is convex at the near optical axis 390, and the image side surface 342 is convex at the near optical axis 390, and the object side surface 341 and the image side are Surfaces 342 are all aspherical.

The fifth lens 350 has a negative refractive power and is made of a plastic material. The object side surface 351 is convex at the near optical axis 390, and the image side surface 352 is concave at the near optical axis 390, and the object side surface 351 and the image side are The surface 352 is aspherical, and at least one surface of the object side surface 351 and the image side surface 352 has at least one inflection point.

Refer to Table 5 and Table 6 below for reference.

In the third embodiment, the aspherical curve equation represents the form as in the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and are not described herein.

With Table 5 and Table 6, the following data can be derived:

The wide-angle lens group provided by the invention can be made of plastic or glass. When the lens material is plastic, the production cost can be effectively reduced. When the lens is made of glass, the degree of freedom of the refractive power of the wide-angle lens group can be increased. In addition, the object side surface and the image side surface of the lens in the wide-angle lens group may be aspherical surfaces, and the aspherical surface can be easily formed into a shape other than the spherical surface, and more control variables are obtained to reduce the aberration and thereby reduce the number of lenses used. Therefore, the total length of the wide-angle lens group of the present invention can be effectively reduced.

In the wide-angle lens group provided by the present invention, in the case of a lens having a refractive power, if the surface of the lens is convex and the position of the convex surface is not defined, it indicates that the surface of the lens is convex at the near optical axis; When the concave surface is not defined and the concave position is not defined, it indicates that the lens surface is concave at the near optical axis.

The wide-angle lens group provided by the invention is more suitable for the optical system of moving focus, and has the characteristics of excellent aberration correction and good imaging quality, and can be applied to 3D (3D) image capturing, digital camera, and action in various aspects. In electronic imaging systems such as devices, digital tablets or car photography.

In the above, the above embodiments and drawings are only the preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, that is, the equivalent changes and modifications made by the scope of the present invention are all It should be within the scope of the patent of the present invention.

100, 200, 300‧ ‧ aperture

110, 210, 310‧‧‧ first lens

111, 211, 311‧‧‧ ‧ side surface

112, 212, 312‧‧‧ side surface

120, 220, 320‧‧‧ second lens

121, 221, 321‧‧‧ ‧ side surface

122, 222, 322‧‧‧ image side surface

130, 230, 330‧‧‧ third lens

131, 231, 331‧‧‧ ‧ side surface

132, 232, 332‧‧‧ image side surface

140, 240, 340‧ ‧ fourth lens

141, 241, 341‧‧‧ ‧ side surface

142, 242, 342‧‧‧ image side surface

150, 250, 350‧‧‧ fifth lens

151, 251, 351‧‧‧ ‧ side surface

152, 252, 352‧‧‧ side surface

170, 270‧‧‧ Infrared filter components

180, 280, 380‧‧ ‧ imaging surface

190, 290, 390‧‧‧ optical axis

f‧‧‧Focus of the wide-angle lens group

Aperture value of Fno‧‧‧ wide-angle lens group

Maximum field of view in the FOV‧‧‧ wide-angle lens group

F1‧‧‧The focal length of the first lens

F2‧‧‧The focal length of the second lens

f3‧‧‧The focal length of the third lens

F4‧‧‧The focal length of the fourth lens

f5‧‧‧Focus of the fifth lens

F12‧‧‧Combined focal length of the first lens and the second lens

F23‧‧‧Combined focal length of the second lens and the third lens

F34‧‧‧Combined focal length of the third lens and the fourth lens

F45‧‧‧Combined focal length of the fourth lens and the fifth lens

F123‧‧‧Combined focal length of the first lens, the second lens and the third lens

f234‧‧‧Combined focal length of the second lens, the third lens and the fourth lens

F2345‧‧‧Combined focal length of the second lens, the third lens, the fourth lens and the fifth lens

V2‧‧‧Dispersion coefficient of the second lens

V3‧‧‧Dispersion coefficient of the third lens

V4‧‧‧Dispersion coefficient of the fourth lens

Dispersion coefficient of V5‧‧‧ fifth lens

TL‧‧‧The distance from the object side surface of the first lens to the imaging surface on the optical axis

Fig. 1A is a schematic view showing a wide-angle lens group of a first embodiment of the present invention. Fig. 1B is a graph showing the curvature of field and the distortion of the wide-angle lens group of the first embodiment from left to right. 2A is a schematic view of a wide-angle lens group of a second embodiment of the present invention. 2B is a graph showing the curvature of field and the distortion of the wide-angle lens group of the second embodiment from left to right. Fig. 3A is a schematic view showing a wide-angle lens group of a third embodiment of the present invention. Fig. 3B is a graph showing the curvature of field and the distortion of the wide-angle lens group of the third embodiment, from left to right.

Claims (20)

A wide-angle lens group comprising: an aperture from the object side to the image side; a first lens having a negative refractive power, the object side surface being convex at a near optical axis, and the image side surface having a concave surface at a near optical axis, At least one surface of the object side surface and the image side surface is aspherical; a second lens has a positive refractive power, and the object side surface is convex at the near optical axis, and the image side surface is convex at the near optical axis, and the object side thereof At least one surface of the surface and the image side surface is aspherical; a third lens having a negative refractive power, the image side surface having a concave surface at a near optical axis, and at least one surface of the object side surface and the image side surface being aspherical; The fourth lens has a positive refractive power, and the object side surface is convex at the near optical axis, and the image side surface is convex at the near optical axis, and at least one surface of the object side surface and the image side surface is aspherical; a fifth lens, The object has a negative refractive power, and the object side surface has a convex surface at a near optical axis, and the image side surface has a concave surface at a near optical axis, and at least one surface of the object side surface and the image side surface is aspherical, the object side surface and the image side surface thereof. At least one surface has at least one inflection point. The wide-angle lens group according to claim 1, wherein the focal length of the first lens is f1, the focal length of the second lens is f2, and the following condition is satisfied: -2.4 < f1/f2 < -0.8. The wide-angle lens group according to claim 1, wherein the focal length of the second lens is f2, the focal length of the third lens is f3, and the following condition is satisfied: -1.1 < f2/f3 < -0.6. The wide-angle lens group according to claim 1, wherein the focal length of the third lens is f3, the focal length of the fourth lens is f4, and the following condition is satisfied: -1.8 < f3/f4 < -0.5. The wide-angle lens group according to claim 1, wherein the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, and the following condition is satisfied: -0.8 < f4/f5 < -0.05. The wide-angle lens group according to claim 1, wherein the focal length of the first lens is f1, the focal length of the third lens is f3, and the following condition is satisfied: 0.7 < f1/f3 < 2.0. The wide-angle lens group according to claim 1, wherein the focal length of the second lens is f2, the focal length of the fourth lens is f4, and the following condition is satisfied: 0.3 < f2/f4 < 1.5. The wide-angle lens group according to claim 1, wherein the focal length of the third lens is f3, the focal length of the fifth lens is f5, and the following condition is satisfied: 0.05 < f3 / f5 < 1.0. The wide-angle lens group according to claim 1, wherein a focal length of the first lens is f1, a combined focal length of the second lens and the third lens is f23, and the following condition is satisfied: -1.3 < f1/f23 < -0.25. The wide-angle lens group according to claim 1, wherein the combined focal length of the second lens and the third lens is f23, the combined focal length of the fourth lens and the fifth lens is f45, and the following condition is satisfied: 0.6 <f23/f45 < 3.6. The wide-angle lens group according to claim 1, wherein a composite focal length of the first lens and the second lens is f12, a combined focal length of the third lens and the fourth lens is f34, and the following condition is satisfied: -0.1 < f12/ F34 < 0.8. The wide-angle lens group according to claim 1, wherein the combined focal length of the third lens and the fourth lens is f34, the focal length of the fifth lens is f5, and the following condition is satisfied: -2.3 < f34/f5 < 6.8. The wide-angle lens group according to claim 1, wherein a focal length of the first lens is f1, a combined focal length of the second lens, the third lens, and the fourth lens is f234, and the following condition is satisfied: -2.2 < f1/f234 < -0.5. The wide-angle lens group according to claim 1, wherein a composite focal length of the second lens, the third lens, and the fourth lens is f234, and a focal length of the fifth lens is f5, and the following condition is satisfied: -0.9 < f234/f5 < -0.05. The wide-angle lens group according to claim 1, wherein the first lens, the second lens and the third lens have a combined focal length of f123, the fourth lens has a focal length of f4, and satisfies the following condition: -4.9 < f123/f4 < 4.5. The wide-angle lens group according to claim 1, wherein the first lens, the second lens and the third lens have a combined focal length of f123, and the fourth lens and the fifth lens have a combined focal length of f45, and satisfy the following conditions: 5.1< f123/f45 < 3.5. The wide-angle lens group according to claim 1, wherein a focal length of the first lens is f1, and a combined focal length of the second lens, the third lens, the fourth lens, and the fifth lens is f2345, and the following condition is satisfied: -2.5 < f1/f2345 < -1.2. The wide-angle lens group according to claim 1, wherein the second lens has a dispersion coefficient of V2, the third lens has a dispersion coefficient of V3, and satisfies the following condition: 29 < V2-V3 < 42. The wide-angle lens group according to claim 1, wherein the fourth lens has a dispersion coefficient of V4, the fifth lens has a dispersion coefficient of V5, and satisfies the following condition: 29 < V4-V5<42. The wide-angle lens group according to claim 1, wherein the entire focal length of the wide-angle lens group is f, the distance from the object-side surface of the first lens to the imaging plane on the optical axis is TL, and the following condition is satisfied: 0.05 < f /TL < 0.4.