TWI662313B - Four-piece optical lens system - Google Patents

Abstract

The invention is a four-piece imaging lens group, which includes, in order from the object side to the image side: an aperture; a first lens having a positive refractive power; a second lens having a negative refractive power; a third lens having a A positive refractive power; and a fourth lens having a negative refractive power. Accordingly, the present invention provides a four-piece imaging lens group that can be applied to portable electronic products without causing the total lens length to be too long, and also has a long focal length, high pixels, and low lens height.

Description

Four-piece imaging lens group

The invention relates to a four-piece imaging lens group, in particular to a miniaturized four-piece imaging lens group applied to electronic products.

High-quality small-sized photographic lenses are now standard equipment for various mobile devices. With the advancement of semiconductor manufacturing, the area of pixels on electronic photosensitive elements is becoming smaller and smaller, which in turn requires more detailed analysis of camera lenses. So that you can present more detailed picture quality.

Miniaturized photographic lenses that are traditionally mounted on portable electronic products mostly use four-piece lens structures. However, as electronic products such as mobile phones and cameras continue to trend toward thinner, lighter, higher performance, and higher picture elements, photosensitive elements As the area of pixels gradually shrinks, and the requirements of system imaging quality continue to increase, the conventional four-piece lens group will not be able to meet higher-level photographic lens modules.

Therefore, how to develop an imaging lens group that can solve the above defects is the motive of the invention.

The object of the present invention is to provide a four-piece imaging lens group, and more particularly to an imaging lens unit that can be applied to portable electronic products without causing the total lens length to be too long, and having both a long focal length, high pixels, and low lens height. Four-piece imaging lens group.

The reason is that, in order to achieve the foregoing object, a four-piece imaging lens group provided according to the present invention includes, in order from the object side to the image side: an aperture; a first lens having a positive refractive power, and an object side surface thereof is near The optical axis is convex and its image side surface is convex near the optical axis. Its object-side surface and image-side surface are at least One surface is aspherical; a second lens has negative refractive power, and its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, and at least one of its object-side surface and image-side surface is An aspheric surface; a third lens having a positive refractive power, the object side surface of which is near the optical axis is concave, the image side surface of which is near the optical axis is convex, and at least one of the object side surface and the image side surface is aspheric; A fourth lens has a negative refractive power. The object-side surface is concave at the near optical axis, the image-side surface is convex at the near-optical axis, and at least one of the object-side surface and the image-side surface is aspherical.

Preferably, the focal length of the first lens is f1, and the focal length of the second lens is f2, and the following conditions are satisfied: -0.9 <f1 / f2 <-0.4. Thereby, the configuration of the refractive power of the first lens and the second lens is more appropriate, which can help reduce the excessive increase of the system aberration.

Preferably, the focal length of the second lens is f2, and the focal length of the third lens is f3, and the following conditions are satisfied: -1.0 <f2 / f3 <-0.3. Thereby, the configuration of the refractive power of the second lens and the third lens is relatively balanced, which contributes to correction of aberrations and reduction of sensitivity.

Preferably, the focal length of the third lens is f3, and the focal length of the fourth lens is f4, and the following conditions are satisfied: -1.9 <f3 / f4 <-1.3. This effectively reduces the overall optical length of the system.

Preferably, the focal length of the first lens is f1, and the focal length of the third lens is f3, and the following conditions are satisfied: 0.35 <f1 / f3 <0.48. Thereby, the refractive power of the first lens is effectively distributed, and the sensitivity of the four-piece imaging lens group is reduced.

Preferably, the focal length of the first lens is f1, and the focal length of the third lens is f4, and the following conditions are satisfied: -0.9 <f1 / f4 <-0.4. Thereby, the refractive power of the first lens is effectively distributed, and the sensitivity of the four-piece imaging lens group is reduced.

Preferably, the focal length of the second lens is f2, and the focal length of the fourth lens is f4, and the following conditions are satisfied: 0.7 <f2 / f4 <1.4. In this way, the system's negative inflection force distribution is more appropriate, which is conducive to correcting system aberrations and improving system imaging quality.

Preferably, the focal length of the first lens is f1, and the combined focal length of the second lens and the third lens is f23, and the following conditions are satisfied: -0.3 <f1 / f23 <0.2. Thus, when f1 / f23 meets the above conditions, the resolution of the four-piece imaging lens group can be significantly improved.

Preferably, 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 conditions are satisfied: -0.6 <f12 / f34 <-0.2. This can effectively correct the curvature of the image surface.

Preferably, a combined focal length of the second lens and the third lens is f23, a focal length of the fourth lens is f4, and the following conditions are satisfied: -28 <f23 / f4 <7.2. When f23 / f4 satisfies the aforementioned relationship, the four-piece imaging lens group can have a high pixel and a low lens height, and at the same time, the resolution can be significantly improved. Conversely, if it exceeds the above-mentioned optical data range, it will As a result, the performance, low resolution, and insufficient yield of the four-piece imaging lens group are caused.

Preferably, the focal length of the first lens is f1, and the combined focal length of the second lens, the third lens, and the fourth lens is f234, and the following conditions are satisfied: -1.3 <f1 / f234 <-0.7. With proper configuration of the inflection force, it helps to reduce the occurrence of spherical aberration and astigmatism.

Preferably, the combined focal length of the first lens, the second lens, and the third lens is f123, and the focal length of the fourth lens is f4, and the following conditions are satisfied: -1.1 <f123 / f4 <-0.7. With proper configuration of the inflection force, it helps to reduce the occurrence of spherical aberration and astigmatism.

Preferably, the dispersion coefficient of the first lens is V1, and the dispersion coefficient of the second lens is V2, and the following conditions are satisfied: 27 <V1-V2 <40. Thereby, the chromatic aberration of the four-piece imaging lens group is effectively reduced.

Preferably, the dispersion coefficient of the fourth lens is V4, and the dispersion coefficient of the third lens is V3, and the following conditions are satisfied: 27 <V4-V3 <40. Thereby, the chromatic aberration of the four-piece imaging lens group is effectively reduced.

Preferably, the overall focal length of the four-piece imaging lens group is f, and the distance from the object-side surface of the first lens to the imaging surface on the optical axis is TL, and satisfies the following conditions: 0.8 <f / TL <1.2 . This can help to maintain the miniaturization of the four-piece imaging lens set for mounting on thin and light electronic products.

Regarding the technology, means, and other effects adopted by the present invention to achieve the foregoing objectives, five preferred feasible embodiments are described in detail below with reference to the drawings.

100, 200, 300, 400, 500‧‧‧ aperture

110, 210, 310, 410, 510‧‧‧ first lens

111, 211, 311, 411, 511‧‧‧ object-side surface

112, 212, 312, 412, 512‧‧‧ image side surface

120, 220, 320, 420, 520‧‧‧ second lens

121, 221, 321, 421, 521‧‧‧ object-side surface

122, 222, 322, 422, 522‧‧‧ image side surface

130, 230, 330, 430, 530‧‧‧ Third lens

131, 231, 331, 431, 531‧‧‧ object-side surface

132, 232, 332, 432, 532‧‧‧ image side surface

140, 240, 340, 440, 540‧‧‧ Fourth lens

141, 241, 341, 441, 541‧‧‧ object-side surface

142, 242, 342, 442, 542‧‧‧ image side surface

170, 270, 370, 470, 570‧‧‧IR filter

180, 280, 380, 480, 580‧‧‧ imaging surface

190, 290, 390, 490, 590‧‧‧ Optical axis

f‧‧‧Focal length of four-piece imaging lens group

Aperture value of Fno‧‧‧ four-piece imaging lens group

FOV‧‧‧Maximum field of view in four-piece imaging lens group

f1‧‧‧ focal length of the first lens

f2‧‧‧ focal length of the second lens

f3‧‧‧ focal length of the third lens

f4‧‧‧ focal length of the fourth lens

f5‧‧‧ the focal length of the fifth lens

f12‧‧‧The combined focal length of the first lens and the second lens

f23‧‧‧The combined focal length of the second lens and the third lens

f34‧‧‧The combined focal length of the third lens and the fourth lens

f123‧‧‧The combined focal length of the first lens, the second lens and the third lens

f234‧‧‧The combined focal length of the second, third, and fourth lenses

V1‧‧‧ Dispersion coefficient of the first lens

V2‧‧‧The dispersion coefficient of the second lens

V3‧‧‧ Dispersion coefficient of the third lens

V4‧‧‧ Dispersion coefficient of the fourth lens

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

FIG. 1A is a schematic diagram of a four-piece imaging lens group according to the first embodiment of the present invention.

FIG. 1B is a curve diagram of the curvature and distortion of the image plane of the four-piece imaging lens group of the first embodiment in order from left to right.

FIG. 2A is a schematic diagram of a four-piece imaging lens group according to a second embodiment of the present invention.

FIG. 2B is a curve diagram of the curvature and distortion of the image plane of the four-piece imaging lens group of the second embodiment in order from left to right.

3A is a schematic diagram of a four-piece imaging lens group according to a third embodiment of the present invention.

FIG. 3B is a curve diagram of the curvature and distortion of the image plane of the four-piece imaging lens group of the third embodiment in order from left to right.

4A is a schematic diagram of a four-piece imaging lens group according to a fourth embodiment of the present invention.

FIG. 4B is a curve diagram of the curvature and distortion of the image plane of the four-piece imaging lens group of the fourth embodiment in order from left to right.

5A is a schematic diagram of a four-piece imaging lens group according to a fifth embodiment of the present invention.

FIG. 5B is a curve diagram of the curvature and distortion of the image plane of the four-piece imaging lens group of the fifth embodiment in order from left to right.

<First Embodiment>

Please refer to FIG. 1A and FIG. 1B. FIG. 1A shows a schematic diagram of a four-piece imaging lens group according to the first embodiment of the present invention, and FIG. 1B is a four-piece imaging lens group of the first embodiment in order from left to right. Curved and distorted narrowing of the image plane. It can be seen from FIG. 1A that the four-piece imaging lens group includes an aperture 100 and an optical group. The optical group sequentially includes the first lens 110, the second lens 120, the third lens 130, and the fourth lens from the object side to the image side. The lens 140, the infrared filtering element 170, and the imaging surface 180. Among the four-piece imaging lens group, four lenses have refractive power. The aperture 100 is disposed between the object-side surface 111 and the image-side surface 112 of the first lens 110.

The first lens 110 has a positive refractive power and is made of plastic. The object-side surface 111 is convex near the optical axis 190, the image-side surface 112 is convex near the optical axis 190, and the object-side surface 111 and the image side The surfaces 112 are all aspheric.

The second lens 120 has a negative refractive power and is made of plastic. The object-side surface 121 is convex near the optical axis 190, the image-side surface 122 is concave near the optical axis 190, and the object-side surface 121 and the image side The surfaces 122 are all aspheric.

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

The fourth lens 140 has a negative refractive power and is made of plastic. The object-side surface 141 is concave near the optical axis 190, the image-side surface 142 is convex near the optical axis 190, and the object-side surface 141 and the image side The surface 142 is an aspheric surface, and at least one surface of the object-side surface 141 and the image-side surface 142 has at least one inflection point.

The infrared filter element 170 is made of glass and is disposed between the fourth lens 140 and the imaging surface 180 without affecting the focal length of the four-piece imaging lens group.

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

Where z is the position value with the surface apex as the reference at the height h along the direction of the optical axis 190; c is the curvature of the lens surface near the optical axis 190, and is the inverse 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 the conic constant, and A, B, C, D, E, G, ... ... is a higher-order aspheric coefficient.

In the four-piece imaging lens group of the first embodiment, the focal length of the four-piece imaging lens group is f, the aperture value (f-number) of the four-piece imaging lens group is Fno, and the maximum vision in the four-piece imaging lens group is The field angle (painting angle) is FOV, and its values are as follows: f = 5.366 (mm); Fno = 2.4; and FOV = 45.8 (degrees).

In the four-piece imaging lens group of the first embodiment, the focal length of the first lens 110 is f1, and the focal length of the second lens 120 is f2, and the following conditions are satisfied: f1 / f2 = -0.64.

In the four-piece imaging lens group of the first embodiment, the focal length of the second lens 120 is f2, and the focal length of the third lens 130 is f3, and the following conditions are satisfied: f2 / f3 = -0.54.

In the four-piece imaging lens group of the first embodiment, the focal length of the third lens 130 is f3, and the focal length of the fourth lens 140 is f4, and the following conditions are satisfied: f3 / f4 = -1.74.

In the four-piece imaging lens group of the first embodiment, the focal length of the first lens 110 is f1, and the focal length of the third lens 130 is f3, and the following conditions are satisfied: f1 / f3 = 0.35.

In the four-piece imaging lens group of the first embodiment, the focal length of the first lens 110 is f1, and the focal length of the fourth lens 140 is f4, and the following conditions are satisfied: f1 / f4 = -0.60.

In the four-piece imaging lens group of the first embodiment, the focal length of the second lens 120 is f2, and the focal length of the fourth lens 140 is f4, and the following conditions are satisfied: f2 / f4 = 0.94.

In the four-piece imaging lens group of the first embodiment, the focal length of the first lens 110 is f1, and the combined focal length of the second lens 120 and the third lens 130 is f23, and satisfies the following conditions: f1 / f23 = -0.14 .

In the four-piece imaging lens group of the first embodiment, the combined focal length of the first lens 110 and the second lens 120 is f12, the combined focal distance of the third lens 130 and the fourth lens 140 is f34, and the following conditions are satisfied: f12 / f34 = -0.43.

In the four-piece imaging lens group of the first embodiment, the combined focal length of the second lens 120 and the third lens 130 is f23, the focal length of the fourth lens 140 is f4, and the following conditions are satisfied: f23 / f4 = 4.21.

In the four-piece imaging 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 satisfies the following conditions: f1 / f234 = -1.02.

In the four-piece imaging 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, the focal length of the fourth lens 140 is f4, and the following conditions are satisfied: f123 /f4=-0.90.

In the four-piece imaging lens group of the first embodiment, the dispersion coefficient of the first lens 110 is V1, and the dispersion coefficient of the second lens 120 is V2, and the following conditions are satisfied: V1-V2 = 34.20.

In the four-piece imaging lens group of the first embodiment, the dispersion coefficient of the fourth lens 140 is V4, and the dispersion coefficient of the third lens 130 is V3, and the following conditions are satisfied: V4-V3 = 34.20.

In the four-piece imaging lens group of the first embodiment, the overall focal length of the four-piece imaging lens group is f, and the distance from the object-side surface 111 of the first lens 110 to the imaging surface 180 on the optical axis 190 is TL, And meet the following conditions: f / TL = 1.02.

Refer to Tables 1 and 2 below for further cooperation.

Table 1 is the detailed structural data of the first embodiment of FIG. 1A, where the units of the radius of curvature, thickness, and focal length are mm, and the surface 0-13 shows the surface from the object side to the image side in order. Table 2 is the aspherical data in the first embodiment, where k represents the cone coefficient in the aspheric curve equation, and A, B, C, D, E, F, G, ... are high-order aspheric coefficients. In addition, the following example tables are schematic diagrams corresponding to the examples. As with the curvature curve of the image plane and the distortion, the definitions of the data in the table are the same as those in Tables 1 and 2 of the first embodiment, and will not be repeated here.

<Second Embodiment>

Please refer to FIG. 2A and FIG. 2B. FIG. 2A shows a schematic diagram of a four-piece imaging lens group according to a second embodiment of the present invention. FIG. 2B is a four-piece imaging lens group of the second embodiment in order from left to right. Curved and distorted narrowing of the image plane. It can be seen from FIG. 2A that the four-piece imaging lens group includes an aperture 200 and an optical group, and the optical group includes the first lens 210, the second lens 220, the third lens 230, and the fourth lens in order from the object side to the image side. The lens 240, the infrared filtering element 270, and the imaging surface 280. Among the four-piece imaging lens group, four lenses have refractive power. The aperture 200 is disposed between the object-side surface 211 and the image-side surface 212 of the first lens 210.

The first lens 210 has a positive refractive power and is made of plastic. The object-side surface 211 is convex near the optical axis 290, the image-side surface 212 is convex near the optical axis 290, and the object-side surface 211 and the image side The surfaces 212 are all aspheric.

The second lens 220 has a negative refractive power and is made of plastic. An object-side surface 221 of the second lens 220 is convex near the optical axis 290, an image-side surface 222 of the second lens 220 is concave near the optical axis 290, and the object-side surface 221 and the image side The surfaces 222 are all aspheric.

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

The fourth lens 240 has a negative refractive power and is made of plastic. Its object-side surface 241 is concave near the optical axis 290, its image-side surface 242 is convex near the optical axis 290, and the object-side surface 241 and the image side The surface 242 is an aspheric surface, and at least one surface of the object-side surface 241 and the image-side surface 242 has at least one inflection point.

The infrared filter element 270 is made of glass and is disposed between the fourth lens 240 and the imaging surface 280 without affecting the focal length of the four-piece imaging lens group.

Refer to Table 3 and Table 4 below for further cooperation.

In the second embodiment, the aspherical curve equation is expressed as the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and will not be repeated here.

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

<Third Embodiment>

Please refer to FIG. 3A and FIG. 3B. FIG. 3A shows a schematic diagram of a four-piece imaging lens group according to a third embodiment of the present invention, and FIG. 3B is a four-piece imaging lens group of the third embodiment in order from left to right. Curved and distorted narrowing of the image plane. It can be seen from FIG. 3A that the four-piece imaging lens group includes an aperture 300 and an optical group, and the optical group sequentially includes the first lens 310, the second lens 320, the third lens 330, and the fourth lens from the object side to the image side. The lens 340, the infrared filtering element 370, and the imaging surface 380. Among the four-piece imaging lens group, there are four lenses with refractive power. The aperture 300 is disposed between the object-side surface 311 and the image-side surface 312 of the first lens 310.

The first lens 310 has a positive refractive power and is made of plastic. The object-side surface 311 is convex near the optical axis 390, the image-side surface 312 is convex near the optical axis 390, and the object-side surface 311 and the image side The surfaces 312 are all aspheric.

The second lens 320 has a negative refractive power and is made of plastic. The object-side surface 321 is convex near the optical axis 390, the image-side surface 322 is concave near the optical axis 390, and the object-side surface 321 and the image side The surfaces 322 are all aspheric.

The third lens 330 has a positive refractive power and is made of plastic. The object-side surface 331 is concave near the optical axis 390, the image-side surface 332 is convex near the optical axis 390, and the object-side surface 331 and the image side The surfaces 332 are all aspherical.

The fourth lens 340 has a negative refractive power and is made of plastic. The object-side surface 341 is a concave surface near the optical axis 390, and its image-side surface 342 is a convex surface near the optical axis 390. The object-side surface 341 and the image side The surface 342 is an aspheric surface, and at least one surface of the object-side surface 341 and the image-side surface 342 has at least one inflection point.

The infrared filter element 370 is made of glass and is disposed between the fourth lens 340 and the imaging surface 380 without affecting the focal length of the four-piece imaging lens group.

Refer to Table 5 and Table 6 below for further cooperation.

In the third embodiment, the aspherical curve equation is expressed as the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and will not be repeated here.

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

<Fourth Embodiment>

Please refer to FIGS. 4A and 4B. FIG. 4A is a schematic diagram of a four-piece imaging lens group according to a fourth embodiment of the present invention. FIG. 4B is a four-piece imaging lens group of the fourth embodiment in order from left to right. Curved and distorted narrowing of the image plane. It can be seen from FIG. 4A that the four-piece imaging lens group includes an aperture 400 and an optical group, and the optical group sequentially includes the first lens 410, the second lens 420, the third lens 430, and the fourth lens from the object side to the image side. The lens 440, the infrared filtering element 470, and the imaging surface 480. Among the four-piece imaging lens group, four lenses have refractive power. The aperture 400 is disposed between the object-side surface 411 and the image-side surface 412 of the first lens 410.

The first lens 410 has a positive refractive power and is made of plastic. The object-side surface 411 is convex near the optical axis 490, the image-side surface 412 is convex near the optical axis 490, and the object-side surface 411 and the image side The surfaces 412 are all aspherical.

The second lens 420 has a negative refractive power and is made of plastic. The object-side surface 421 is convex near the optical axis 490, the image-side surface 422 is concave near the optical axis 490, and the object-side surface 421 and the image side The surfaces 422 are all aspherical.

The third lens 430 has a positive refractive power and is made of plastic. The object-side surface 431 is concave near the optical axis 490, the image-side surface 432 is convex near the optical axis 490, and the object-side surface 431 and the image side The surfaces 432 are all aspheric.

The fourth lens 440 has a negative refractive power and is made of plastic. The object-side surface 441 is concave near the optical axis 490, the image-side surface 442 is convex near the optical axis 490, and the object-side surface 441 and the image side The surface 442 is an aspheric surface, and at least one surface of the object-side surface 441 and the image-side surface 442 has at least one inflection point.

The infrared filter element 470 is made of glass and is disposed between the fourth lens 440 and the imaging surface 480 without affecting the focal length of the four-piece imaging lens group.

Refer to Table 7 and Table 8 below for further cooperation.

In the fourth embodiment, the curve equation of the aspherical surface is expressed as the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and will not be repeated here.

With Table 7 and Table 8, the following data can be calculated:

<Fifth Embodiment>

Please refer to FIGS. 5A and 5B. FIG. 5A is a schematic diagram of a four-piece imaging lens group according to a fifth embodiment of the present invention. FIG. 5B is a four-piece imaging lens group of the fifth embodiment in order from left to right. Curved and distorted narrowing of the image plane. It can be seen from FIG. 5A that the four-piece imaging lens group includes an aperture 500 and an optical group, and the optical group sequentially includes the first lens 510, the second lens 520, the third lens 530, and the fourth lens from the object side to the image side. The lens 540, the infrared filtering element 570, and the imaging surface 580. Among the four-piece imaging lens group, four lenses have refractive power. The aperture 500 is disposed between the object-side surface 511 and the image-side surface 512 of the first lens 510.

The first lens 510 has a positive refractive power and is made of plastic. The object-side surface 511 is convex near the optical axis 590, and the image-side surface 512 is convex near the optical axis 590. The object-side surface 511 and the image side The surfaces 512 are all aspheric.

The second lens 520 has a negative refractive power and is made of plastic. The object-side surface 521 is convex near the optical axis 590, the image-side surface 522 is concave near the optical axis 590, and the object-side surface 521 and the image side The surfaces 522 are all aspherical.

The third lens 530 has a positive refractive power and is made of plastic. The object-side surface 531 of the third lens 530 is concave near the optical axis 590, the image-side surface 532 of the third lens 530 is convex near the optical axis 590, and the object-side surface 531 and the image side The surfaces 532 are all aspherical.

The fourth lens 540 has a negative refractive power and is made of plastic. The object-side surface 541 of the fourth lens 540 is concave near the optical axis 590, the image-side surface 542 of the fourth lens 540 is convex near the optical axis 590, and the object-side surface 541 and the image side The surfaces 542 are all aspheric, and at least one surface of the object-side surface 541 and the image-side surface 542 has at least one inflection point.

The infrared filtering element 570 is made of glass and is disposed between the fourth lens 540 and the imaging surface 580 without affecting the focal length of the four-piece imaging lens group.

Refer to Table 9 and Table 10 below for further cooperation.

In the fifth embodiment, the aspherical curve equation is expressed as the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and will not be repeated here.

With Table 9 and Table 10, the following data can be calculated:

In the four-piece imaging lens group provided by the present invention, the material of the lens can be plastic or glass. When the material of the lens is plastic, the production cost can be effectively reduced. When the material of the lens is glass, the inflection of the four-piece imaging lens group can be increased. Degree of freedom in force configuration. In addition, the object of the lens in the four-piece imaging lens group The side surface and the image side surface can be aspheric, and the aspheric surface can be easily made into a shape other than a spherical surface, to obtain more control variables to reduce aberrations, thereby reducing the number of lenses used, so the four lenses of the present invention can be effectively reduced. Total length of the imaging lens group.

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

The four-piece imaging lens set provided by the present invention can be more applied to the optical system of mobile focusing according to requirements, and has both the characteristics of excellent aberration correction and good imaging quality, and can be applied to 3D (three-dimensional) image capture, digital Cameras, mobile devices, digital tablets, or automotive photography.

In summary, the above-mentioned embodiments and drawings are only preferred embodiments of the present invention. When the scope of implementation of the present invention cannot be limited by this, that is, all equal changes and modifications made in accordance with the scope of the patent application of the present invention, It should be within the scope of the invention patent.

Claims (14)

A four-piece imaging lens group includes, in order from the object side to the image side, an aperture; a first lens having a positive refractive power, a convex surface near the optical axis of the object side surface, and a near optical axis at the image side surface. Is a convex surface, at least one of the object-side surface and the image-side surface is aspheric; a second lens has a negative refractive power, the object-side surface is convex near the optical axis, and the image-side surface is concave near the optical axis; At least one of the object-side surface and the image-side surface is aspherical; a third lens has a positive refractive power, and the object-side surface is concave at the near-optical axis, and the image-side surface thereof is convex at the near-optical axis, and its object-side At least one of the surface and the image-side surface is aspherical; and a fourth lens having a negative refractive power, the object-side surface thereof is concave at the near-optical axis, the image-side surface thereof is convex at the near-optical axis, and the object-side surface and At least one of the image-side surfaces is aspherical; the combined focal length of the first lens and the second lens is f12, the combined focal distance of the third lens and the fourth lens is f34, and the following conditions are satisfied: -0.6 <f12 / f34 ≦ -0.41. The four-piece imaging lens group according to claim 1, wherein the focal length of the first lens is f1, and the focal length of the second lens is f2, and the following conditions are satisfied: -0.9 <f1 / f2 <-0.4. The four-piece imaging lens group according to claim 1, wherein the focal length of the second lens is f2, and the focal length of the third lens is f3, and the following conditions are satisfied: -1.0 <f2 / f3 <-0.3. The four-piece imaging lens group according to claim 1, wherein the focal length of the third lens is f3, and the focal length of the fourth lens is f4, and the following conditions are satisfied: -1.9 <f3 / f4 <-1.3. The four-piece imaging lens group according to claim 1, wherein the focal length of the first lens is f1, and the focal length of the third lens is f3, and the following conditions are satisfied: 0.35 <f1 / f3 <0.48. The four-piece imaging lens group according to claim 1, wherein the focal length of the first lens is f1, and the focal length of the fourth lens is f4, and the following conditions are satisfied: -0.9 <f1 / f4 <-0.4. The four-piece imaging lens group according to claim 1, wherein the focal length of the second lens is f2, and the focal length of the fourth lens is f4, and the following conditions are satisfied: 0.7 <f2 / f4 <1.4. The four-piece imaging lens group according to claim 1, wherein the focal length of the first lens is f1, and the combined focal distance of the second lens and the third lens is f23, and the following conditions are satisfied: -0.3 <f1 / f23 < 0.2. The four-piece imaging lens group according to claim 1, wherein the combined focal length of the second lens and the third lens is f23, the focal length of the fourth lens is f4, and the following conditions are satisfied: -28 <f23 / f4 < 7.2. The four-piece imaging lens group according to claim 1, wherein the focal length of the first lens is f1, and the combined focal length of the second lens, the third lens, and the fourth lens is f234, and the following conditions are satisfied: -1.3 < f1 / f234 <-0.7. The four-piece imaging lens group according to claim 1, wherein the combined focal length of the first lens, the second lens, and the third lens is f123, the focal length of the fourth lens is f4, and the following conditions are satisfied: -1.1 < f123 / f4 <-0.7. The four-piece imaging lens group according to claim 1, wherein the dispersion coefficient of the first lens is V1, and the dispersion coefficient of the second lens is V2, and the following conditions are satisfied: 27 <V1-V2 <40. The four-piece imaging lens group according to claim 1, wherein the dispersion coefficient of the fourth lens is V4, and the dispersion coefficient of the third lens is V3, and the following conditions are satisfied: 27 <V4-V3 <40. The four-piece imaging lens group according to claim 1, wherein the overall focal length of the four-piece imaging lens group is f, and the distance from the object-side surface of the first lens to the imaging surface on the optical axis is TL, and satisfies The following conditions: 0.8 <f / TL <1.2.