TWI738297B - Four-piece imaging lens - Google Patents

Abstract

A four-piece imaging lens includes a first lens, a second lens, a stop, a third lens, and a fourth lens in this order from the object side to the image side. The first lens has negative refractive power, and its object side is convex and its image side is concave. The second lens has positive refractive power, and its object side is convex. The third lens has negative refractive power, and its object side is concave. The fourth lens has positive refractive power, and its object side is convex. The four-piece imaging lens further satisfies the following relationship: 0 >F1 / F3 ≦ 1.5, in which F1 is the focal length value of the first lens and F3 is the focal length value of the third lens, thereby helping improve the imaging quality.

Description

Four-piece imaging lens

The invention relates to an optical lens, in particular to a four-piece imaging lens.

Optical lenses are commonly used by people, and automotive lenses are also commonly used. In this type of lens, if the combination of the front and rear lens groups is not good, the image quality may be poor. Therefore, how to improve the image quality by adjusting the lens structure is a subject worth considering in the field.

The main purpose of the present invention is to provide a four-piece imaging lens that can improve imaging quality, reduce aberrations and spherical aberration, and reduce the size of the lens.

In order to achieve the above and other objectives, the present invention provides a four-piece imaging lens, which includes a first lens, a second lens, an aperture, a third lens, and a fourth lens in sequence from the object side to the image side. The first lens has negative refractive power, its object side is convex and its image side is concave. The second lens has positive refractive power, and its object side is convex. The third lens has negative refractive power and its object side is concave. The fourth lens has positive refractive power, and its object side is convex. Among them, the four-piece imaging lens satisfies the following relationship: 0>F1/F3≦1.5, where F1 is the focal length value of the first lens element, and F3 is the focal length value of the third lens element. By controlling the focal length values of the first lens and the third lens, a better negative refractive power is provided, which helps to balance the system and improve the image quality.

In addition, in the present invention, the first lens has a negative refractive power, the second lens has a positive refractive power, the third lens has a negative refractive power, and the fourth lens has a positive refractive power, that is, the front group (that is, the first lens and the The second lens) and the rear group (that is, the third lens and the fourth lens) are matched with a pair of lenses with positive and negative refractive powers, which can reduce aberrations and smooth the optical path to reduce the size of the lens. In addition, the combination of lenses with positive and negative refractive power in the rear group (that is, the third lens and the fourth lens) can also reduce spherical aberration and shorten the length of the optical system.

As in the aforementioned four-piece imaging lens, the image side surface of the second lens can be a concave surface, the image side surface of the third lens can be a concave surface, and the image side surface of the fourth lens can be a convex surface.

In order to achieve the above and other objectives, the present invention also provides a four-piece imaging lens, which includes a first lens, a second lens, an aperture, a third lens, and a fourth lens in sequence from the object side to the image side. The first lens has negative refractive power, its image side surface is concave, and satisfies the following relationship: R1>R2, where R1 is the curvature radius of the object side surface of the first lens, and R2 is the curvature radius of the image side surface of the first lens. The second lens has positive refractive power, and its object side is convex. The third lens has negative refractive power, its image side surface is concave, and satisfies the following relationship: R5>R6, where R5 is the curvature radius of the object side surface of the third lens, and R6 is the curvature radius of the image side surface of the third lens. The fourth lens has positive refractive power, its image side surface is convex, and satisfies the following relationship: R7>R8, where R7 is the curvature radius of the object side surface of the fourth lens, and R8 is the curvature radius of the image side surface of the fourth lens. Among them, the four-piece imaging lens satisfies the following relationship: 0>F1/F3≦1.5, where F1 is the focal length value of the first lens element, and F3 is the focal length value of the third lens element. By controlling the focal length values of the first lens and the third lens, a better negative refractive power is provided, which helps to balance the system and improve the image quality.

In addition, in the present invention, the first lens has a negative refractive power, the second lens has a positive refractive power, the third lens has a negative refractive power, and the fourth lens has a positive refractive power, that is, the front group (that is, the first lens and the The second lens) and the rear group (that is, the third lens and the fourth lens) are matched with a pair of lenses with positive and negative refractive powers, which can reduce aberrations and smooth the optical path to reduce the size of the lens. In addition, the combination of lenses with positive and negative refractive power in the rear group (that is, the third lens and the fourth lens) can also reduce spherical aberration and shorten the length of the optical system.

As in the aforementioned four-piece imaging lens, the image side of the second lens can be flat or concave, the object side of the third lens can be concave, and the object side of the fourth lens can be convex.

In order to achieve the above and other objectives, the present invention provides a four-piece imaging lens, which includes a first lens, a second lens, an aperture, a third lens, and a fourth lens in sequence from the object side to the image side. The first lens has negative refractive power and satisfies the following relationship: R1×R2>0, and R1>R2, where R1 is the radius of curvature of the object side of the first lens, and R2 is the radius of curvature of the image side of the first lens. The second lens has positive refractive power and its object side surface is convex; the third lens has negative refractive power and satisfies the following relationship: R5×R6>0, and R5>R6, where R5 is the curvature radius of the object side surface of the third lens, R6 is the radius of curvature of the image side surface of the third lens. The fourth lens has positive refractive power and satisfies the following relationship: R7×R8>0, and R7>R8, where R7 is the radius of curvature of the object side of the fourth lens, and R8 is the radius of curvature of the image side of the fourth lens. Among them, the four-piece imaging lens satisfies the following relationship: 0>F1/F3≦1.5, where F1 is the focal length value of the first lens element, and F3 is the focal length value of the third lens element. By controlling the focal length values of the first lens and the third lens, a better negative refractive power is provided, which helps to balance the system and improve the image quality.

In addition, in the present invention, the first lens has a negative refractive power, the second lens has a positive refractive power, the third lens has a negative refractive power, and the fourth lens has a positive refractive power, that is, the front group (that is, the first lens and the The second lens) and the rear group (that is, the third lens and the fourth lens) are matched with a pair of lenses with positive and negative refractive powers, which can reduce aberrations and smooth the optical path to reduce the size of the lens. In addition, the combination of lenses with positive and negative refractive power in the rear group (that is, the third lens and the fourth lens) can also reduce spherical aberration and shorten the length of the optical system.

As in the aforementioned four-piece imaging lens, the image side surface of the second lens can be flat or concave, the image side surface of the third lens can be concave, and the image side surface of the fourth lens can be convex.

As in the aforementioned four-piece imaging lens, the following relationship is more satisfied: (N2+N4)/2>1.8, where N2 is the refractive index of the second lens, and N4 is the refractive index of the fourth lens. With this design, a shorter overall system length can be provided.

As in the aforementioned four-piece imaging lens, the following relationship is more satisfied: -8>R4/R5>0, where R4 is the radius of curvature of the image side surface of the second lens element, and R5 is the radius of curvature of the object side surface of the third lens element. With this design, the concave surfaces on both sides of the aperture can be made to face the aperture, which helps reduce astigmatism.

For the aforementioned four-piece imaging lens, the following relationship is more satisfied: 3>R4/F>14, where the curvature radius of the image side surface of the second lens of R4, and F is the system focal length of the four-piece imaging lens. With this design, the concave surfaces on both sides of the aperture can be made to face the aperture, which helps reduce astigmatism.

Among the aforementioned four-piece imaging lenses, the following relations can be satisfied: 2.0≦R1/F≦62, 0.3≦R2/F≦0.7, 0.5≦R3/F≦0.8, -1>R5/F≦-0.5, 0.6≦R6/F≦1.2, 1.0≦R7/F≦3.0, -1.5≦R8/F≦-0.5, -1.2≦F/F1≦-0.8, 1.0≦F/F2≦2, -1.5≦F/F3 ≦-1.0, 1.0≦F/F4≦2.0, 3.0≦ALT/Gaa≦5.0, 1.5≦TTL/F≦3.0, 2.0≦FNO≦3.0, where F1 is the focal length of the first lens and F2 is the second lens Focal length value, F3 is the focal length value of the third lens, F4 is the focal length value of the fourth lens, Gaa is the sum of the gap lengths of the first to fourth lens on the optical axis, FNO is the aperture value of the four-piece imaging lens, In this way, the four-piece imaging lens can improve the image quality, reduce aberrations, and shrink the lens.

Please refer to Figure 1, which is the first embodiment of the present invention. A four-piece imaging lens (hereinafter referred to as a four-piece lens) on the optical axis L includes the first camera from the object side A to the image side B. A lens 10, a second lens 20, an aperture ST, a third lens 30, and a fourth lens 40 are provided with CCD, CMOS or other photosensitive elements (not shown) on the image side B. The photosensitive elements and the fourth lens 40 There may be a flat lens 50 such as a filter and/or protective glass, and the number of the flat lens 50 may be increased or decreased or not provided according to requirements. Among them, the first and second lenses 10 and 20 closer to the object side A than the aperture ST are the front lens groups; in contrast, the third and fourth lenses 30 and 40 closer to the image side B than the aperture ST are the rear lens groups. .

The first thing to declare is that in this article, when the center of a curved surface is closer to the image side than the surface itself, the radius of curvature of the curved surface is positive; on the contrary, when the center of a curved surface is closer to the surface itself When it is on the object side, the radius of curvature of the curved surface is a negative value. Unless otherwise specified, the concave and convex shapes and radius of curvature of the "object side" and "image side" refer to the shape and radius of curvature of the surface at the optical axis L.

In the first embodiment of the present invention, the first lens 10 has negative refractive power, its object side surface is convex and its image side surface is concave, the curvature radius of the object side surface and the image side surface are both positive, and the curvature of the object side surface is positive. The radius is greater than the radius of curvature of the image side. Since the first lens 10 is a convex-concave lens with negative refractive power, and its object side is convex toward the object side, it is helpful to realize the miniaturization of the lens and reduce the amount of distortion.

The second lens 20 has a positive refractive power, its object side surface is convex and its image side surface is concave, the curvature radius of the object side surface and the image side surface are both positive, and the curvature radius of the object side surface is smaller than the curvature radius of the image side surface. Since the second lens 20 is a convex-concave lens with positive refractive power, it can be made of a glass material with a high refractive index, and its image side surface is concave, which helps to shorten the overall length of the system, achieve miniaturization of the lens, and balance aberrations.

The third lens 30 has a negative refractive power, the object side surface is concave and the image side surface is concave, the curvature radius of the object side surface is a negative value, and the curvature radius of the image side surface is a positive value. Since the third lens 30 is a biconcave lens with negative refractive power, the object side of its concave surface faces the aperture, thus helping to balance aberrations.

The fourth lens 40 has a positive refractive power, the object side surface is convex and the image side surface is convex, the curvature radius of the object side surface is a positive value, and the curvature radius of the image side surface is a negative value. Since the fourth lens 40 is a biconvex lens with positive refractive power, it can be made of a glass material with a high refractive index, and its image side surface is convex, which helps to shorten the total length of the system and realize the miniaturization of the lens. The combination of positive and negative refractive power can further reduce the spherical aberration.

In the first embodiment, the first lens 10, the third lens 30 and the fourth lens 40 are all glass lenses.

The design parameters of the four-piece imaging lens in this embodiment are shown in Table 1. It should be noted that the distance value corresponding to the object side represents the thickness of the lens on the optical axis L, and the distance value corresponding to the image side represents the thickness of the lens on the optical axis L. The distance between the lens and the next lens or the next aperture ST on the optical axis L:

Table I Table 1, the first embodiment The system focal length value F is 5.64 mm, the system length is 13 mm, and the maximum viewing angle is 64 ^o lens noodle Radius of curvature (mm) distance Refractive index Dispersion coefficient focal length (mm) (Nd) (Vd) (mm) First lens Object side 1 12.45 0.57 1.55 63.33 -5.44 Like side 2 2.35 0.56 Second lens Object side 3 4.22 2.46 2.00 25.47 5.09 Like side 4 21.00 0.17 aperture ∞ 0.21 Third lens Object side 5 -28.82 0.55 1.85 32.27 -5.44 Like side 6 5.37 0.32 Fourth lens Object side 7 12.64 1.65 1.95 32.31 3.42 Like side 8 -3.97 0.5 Flat lens Object side 9 ∞ 0.5 1.52 64.08 Like side 10 ∞ 5.511

According to Table 1, the relational values of the following Table 2 can be obtained:

In the following relationship, R1 is the radius of curvature of the object side of the first lens 10, R2 is the radius of curvature of the image side of the first lens 10, R3 is the radius of curvature of the object side of the second lens 20, and R4 is the image side of the second lens 20 R5 is the curvature radius of the object side surface of the third lens 30, R6 is the curvature radius of the image side surface of the third lens 30, R7 is the curvature radius of the object side surface of the fourth lens 40, and R8 is the curvature of the image side surface of the fourth lens 40 Radius, N2 is the refractive index of the second lens, N4 is the refractive index of the fourth lens, TTL is the total system length of the four-piece imaging lens, and ATL is the thickness of the first lens 10 to the fourth lens 40 on the optical axis L Sum, F is the system focal length of the four-piece imaging lens, F1 is the focal length value of the first lens, F2 is the focal length value of the second lens, F3 is the focal length value of the third lens, and F4 is the focal length value of the fourth lens. Gaa is the sum of the gap lengths of the first to fourth lenses on the optical axis, and FNO is the aperture value of the four-piece imaging lens.

Table II Relation Numerical value Relation Numerical value F1/F3 1.0 (N2+N4)/2 1.98 R4/R5 -0.73 R4/F 3.71 T1/F 0.10 R1/F 2.21 T2/F 0.10 R2/F 0.42 T3/F 0.44 R3/F 0.75 T4/F 0.07 R5/F -5.11 T5/F 0.10 R6/F 0.95 T6/F 0.06 R7/F 2.24 T7/F 0.29 R8/F -0.70 T8/F 0.09 TTL/F 2.30 F/F1 -1.04 ATL/Gaa 4.19 F/F2 1.11 FNO 2.40 F/F3 -1.04 F/F4 1.65

Please refer to FIG. 2 and FIG. 3, which are respectively a field curvature diagram and a distortion diagram of the first embodiment of the present invention. In this embodiment, due to the proper combination of the first lens 10 and the second lens 20 in the front lens group and the third lens 30 and the fourth lens 40 in the rear lens group, the maximum curvature of field does not exceed ±0.10 mm, and Able to achieve optical performance with small optical distortion (>10%). In other words, this embodiment has an excellent imaging effect and effectively reduces aberrations.

Please refer to FIG. 4, which shows the second embodiment of the present invention. The lens configuration is similar to that of the first embodiment. The difference is that the object side and the image side of the fourth lens 40 are both aspherical. The design parameters of the four-piece imaging lens in this embodiment are shown in Table 3 below:

Table Three Table 3, the second embodiment The system focal length value F is 5.45 mm, the system length is 11.56 mm, and the maximum viewing angle is 65.4 ^o lens noodle Radius of curvature (mm) distance Refractive index Dispersion coefficient focal length (mm) (Nd) (Vd) (mm) First lens Object side 1 12.15 0.58 1.55 63.33 -5.80 Like side 2 2.46 0.54 Second lens Object side 3 3.58 1.89 2.00 25.47 3.84 Like side 4 74.68 0.28 aperture ∞ 0.24 Third lens Object side 5 -12.37 0.50 1.85 32.27 -3.94 Like side 6 4.50 0.36 Fourth lens Object side 7 9.89 1.60 1.95 32.31 3.35 Like side 8 -4.18 0.5 Flat lens Object side 9 ∞ 1.04 1.51 64.08 Like side 10 ∞ 4.05

其中，第四鏡片的的物側面及像側面均為非球面，其面型滿足下列非球面公式：

Among them, the object side and image side of the fourth lens are both aspherical, and its surface shape satisfies the following aspherical formula:

Where c=1/r, r is the radius of curvature of the surface, h is the height of the light on the surface, k is the conical coefficient, B is the fourth-order coefficient, C is the sixth-order coefficient, D is the eighth-order coefficient, E Is the tenth-order coefficient, F is the twelfth-order coefficient, and G is the fourteenth-order coefficient. The parameters of each aspheric surface in the second embodiment are shown in Table 4 below:

Table Four Object side 7 Like side 8 B -5.56E-04 2.49E-04 C 0 0 D 0 0 E 0 0 F 0 0 G 0 0

According to Table 3 and Table 4, the following five relational formula values can be obtained:

Table 5 Relation Numerical value Relation Numerical value F1/F3 1.47 (N2+N4)/2 1.98 R4/R5 -6.04 R4/F 13.70 T1/F 0.11 R1/F 2.23 T2/F 0.10 R2/F 0.45 T3/F 0.35 R3/F 0.66 T4/F 0.09 R5/F -2.27 T5/F 0.09 R6/F 0.83 T6/F 0.07 R7/F 1.81 T7/F 0.29 R8/F -0.77 T8/F 0.09 TTL/F 2.12 F/F1 -0.94 ATL/Gaa 3.26 F/F2 1.42 FNO 2.25 F/F3 -1.38 F/F4 1.63

Please refer to FIG. 5 and FIG. 6, which are respectively a field curvature diagram and a distortion diagram of the second embodiment of the present invention. In this embodiment, due to the proper combination of the first lens 10 and the second lens 20 in the front lens group and the third lens 30 and the fourth lens 40 in the rear lens group, the maximum curvature of field does not exceed ±0.10 mm, and Able to achieve optical performance with small optical distortion (>10%). In other words, this embodiment has an excellent imaging effect and effectively reduces aberrations.

Please refer to FIG. 7, which shows the third embodiment of the present invention, and its lens configuration is similar to that of the first embodiment. The design parameters of the four-piece imaging lens in this embodiment are shown in Table 6 below:

Table 6 Table 6, the third embodiment The system focal length value F is 5.5 mm, the system length is 12.21mm, and the maximum viewing angle is 65.4 ^o lens noodle Radius of curvature (mm) distance Refractive index Dispersion coefficient focal length (mm) (Nd) (Vd) (mm) First lens Object side 1 14.93 0.52 1.55 63.33 -5.21 Like side 2 2.35 0.49 Second lens Object side 3 3.81 2.20 2.00 25.47 4.20 Like side 4 43.28 0.17 aperture ∞ 0.22 Third lens Object side 5 -17.17 0.52 1.85 32.27 -4.54 Like side 6 4.86 0.31 Fourth lens Object side 7 11.37 1.70 1.95 32.30 3.36 Like side 8 -3.98 0.5 Flat lens Object side 9 ∞ 0.64 1.52 64.08 Like side 10 ∞ 4.93

According to Table 6, the values of the following seven relations can be obtained:

Table Seven Relation Numerical value Relation Numerical value F1/F3 1.15 (N2+N4)/2 1.98 R4/R5 -2.52 R4/F 7.87 T1/F 0.10 R1/F 2.71 T2/F 0.09 R2/F 0.43 T3/F 0.40 R3/F 0.69 T4/F 0.07 R5/F -3.12 T5/F 0.10 R6/F 0.88 T6/F 0.06 R7/F 2.07 T7/F 0.31 R8/F -0.72 T8/F 0.09 TTL/F 2.22 F/F1 -1.06 ATL/Gaa 4.16 F/F2 1.31 FNO 2.35 F/F3 -1.21 F/F4 1.64

Please refer to FIG. 8 and FIG. 9, which are respectively a field curvature diagram and a distortion diagram of the third embodiment of the present invention. In this embodiment, due to the proper combination of the first lens 10 and the second lens 20 in the front lens group and the third lens 30 and the fourth lens 40 in the rear lens group, the maximum curvature of field does not exceed ±0.10 mm, and Able to achieve optical performance with small optical distortion (>10%). In other words, this embodiment has an excellent imaging effect and effectively reduces aberrations.

Please refer to FIG. 10, which shows the fourth embodiment of the present invention. The lens configuration is similar to that of the first embodiment. The difference is that the image side of the second lens 20 is flat, and the object side of the fourth lens 40 is The image side surfaces are all aspherical. The design parameters of the four-piece imaging lens in this embodiment are shown in Table 8 below:

Table 8 Table 8, the fourth embodiment The system focal length value F is 5.52 mm, the system length is 10.34mm, and the maximum viewing angle is 65.5 ^o lens noodle Radius of curvature (mm) distance Refractive index Dispersion coefficient focal length (mm) (Nd) (Vd) (mm) First lens Object side 1 339.65 0.5 1.52 64.20 -6.32 Like side 2 3.18 0.325 Second lens Object side 3 3.23 1.853 1.95 17.94 3.58 Like side 4 ∞ 0.011 aperture ∞ 0.265 Third lens Object side 5 -4.40 0.5 1.62 36.36 -4.11 Like side 6 5.97 0.433 Fourth lens Object side 7 7.24 1.218 1.95 29.83 3.66 Like side 8 -5.81 0.5 Flat lens Object side 9 ∞ 0.64 1.52 64.13 Like side 10 ∞ 0.4

其中，第四鏡片的的物側面及像側面均為非球面，其面型滿足下列非球面公式：

Among them, the object side and image side of the fourth lens are both aspherical, and its surface shape satisfies the following aspherical formula:

Where c=1/r, r is the radius of curvature of the surface, h is the height of the light on the surface, k is the conical coefficient, B is the fourth-order coefficient, C is the sixth-order coefficient, D is the eighth-order coefficient, E Is the tenth-order coefficient, F is the twelfth-order coefficient, and G is the fourteenth-order coefficient. The parameters of each aspheric surface in the fourth embodiment are shown in Table 9 below:

Table 9 Object side 7 Like side 8 B 3.13E-02 9.93E-04 C -1.55E-02 3.59E-03 D 5.12E-03 -1.34E-03 E -8.16E-04 1.86E-04 F -2.43E-05 1.31E-05 G 2.88E-05 -4.11E-06

According to Table 8 and Table 9, the following ten relational values can be obtained:

Table 10 Relation Numerical value Relation Numerical value F1/F3 1.5 (N2+N4)/2 1.95 T1/F 0.09 R1/F 61.53 T2/F 0.06 R2/F 0.58 T3/F 0.34 R3/F 0.59 T4/F 0.05 R4/F - T5/F 0.09 R5/F -0.80 T6/F 0.08 R6/F 1.08 T7/F 0.22 R7/F 1.31 T8/F 0.09 R8/F -1.05 F/F1 -0.87 TTL/F 1.87 F/F2 1.54 ATL/Gaa 3.94 F/F3 -1.34 FNO 2.4 F/F4 1.51

Please refer to FIG. 11 and FIG. 12, which are respectively a field curvature diagram and a distortion diagram of the fourth embodiment of the present invention. In this embodiment, due to the proper combination of the first lens 10 and the second lens 20 in the front lens group and the third lens 30 and the fourth lens 40 in the rear lens group, the maximum curvature of field does not exceed ±0.10 mm, and Able to achieve optical performance with small optical distortion (>10%). In other words, this embodiment has an excellent imaging effect and effectively reduces aberrations.

With the four-piece imaging lens in one or more of the above embodiments, the first lens has a negative refractive power, the second lens has a positive refractive power, the third lens has a negative refractive power, and the fourth lens has a positive refractive power. The two-lens combination of the front lens group and the two-lens combination of the rear lens group are separated by an aperture to reduce aberrations, improve image quality, and smooth the optical path to reduce the size of the lens. In addition, the second lens and the third lens on both sides of the aperture are made of high refractive index and low dispersion coefficient lens materials, which can reduce astigmatism. The third lens has negative refractive power and the fourth lens is a combination of positive refractive power. In combination, their refractive powers compensate each other, which can reduce spherical aberration and shorten the length of the optical system.

10: The first lens 20: second lens 30: third lens 40: The fourth lens 50: flat lens A: Object side B: Image side ST: Aperture L: Optical axis

Figure 1 is a schematic diagram of the first embodiment of the present invention.

Figure 2 is a field curvature diagram of the first embodiment of the present invention.

Figure 3 is a distortion diagram of the first embodiment of the present invention.

Figure 4 is a schematic diagram of the second embodiment of the present invention.

Figure 5 is a field curvature diagram of the second embodiment of the present invention.

Figure 6 is a distortion diagram of the second embodiment of the present invention.

Figure 7 is a schematic diagram of the third embodiment of the present invention.

Fig. 8 is a field curvature diagram of the third embodiment of the present invention.

Figure 9 is a distortion diagram of the third embodiment of the present invention.

Figure 10 is a schematic diagram of a fourth embodiment of the present invention.

Fig. 11 is a field curvature diagram of the fourth embodiment of the present invention.

Figure 12 is a distortion diagram of the fourth embodiment of the present invention.

10: The first lens

20: second lens

30: third lens

40: The fourth lens

50: flat lens

A: Object side

B: Image side

ST: Aperture

L: Optical axis

Claims (7)

A four-piece imaging lens, from the object side to the image side, includes: a first lens with negative refractive power, a convex surface on the object side surface and a concave surface on the image side surface; a second lens with positive refractive power, and the object side The side surface is convex and its image side is flat or concave; an aperture; a third lens with negative refractive power, its object side is concave and its image side is concave; and a fourth lens with positive refractive power, its object side is Convex; where the four-piece imaging lens satisfies the following relationship: 0<F1/F3≦1.5, where F1 is the focal length value of the first lens element, and F3 is the focal length value of the third lens element; and -8< R4/R5<0, where R4 is the radius of curvature of the image side surface of the second lens, and R5 is the radius of curvature of the object side surface of the third lens. A four-piece imaging lens, from the object side to the image side, sequentially includes: a first lens with negative refractive power, the image side surface is concave, and satisfies the following relationship: R1>R2, where R1 is the first lens The radius of curvature of the object side of the lens, R2 is the radius of curvature of the image side of the first lens; a second lens with positive refractive power, the object side of which is convex and the image side of which is flat or concave; an aperture; a third lens , Has negative refractive power, its image side surface is concave, and satisfies the following relationship: R5<R6, where R5 is the radius of curvature of the object side surface of the third lens, and R6 is the radius of curvature of the image side surface of the third lens; and A fourth lens with positive refractive power, its image side surface is convex, and satisfies the following relationship: R7>R8, where R7 is the curvature radius of the object side surface of the fourth lens, and R8 is the curvature of the image side surface of the fourth lens Radius; where the four-piece imaging lens satisfies the following relationship: 0<F1/F3≦1.5, where F1 is the focal length value of the first lens, and F3 is the focal length value of the third lens. A four-piece imaging lens, from the object side to the image side, sequentially includes: a first lens with negative refractive power and satisfies the following relationship: R1×R2>0, and R1>R2, where R1 is the first lens The curvature radius of the object side surface of the lens, R2 is the curvature radius of the image side surface of the first lens; a second lens with positive refractive power, the object side surface is convex and the image side surface is flat or concave; an aperture; a third lens The lens has negative refractive power and satisfies the following relationship: R5×R6<0, and R5<R6, where R5 is the radius of curvature of the object side of the third lens, and R6 is the radius of curvature of the image side of the third lens; And a fourth lens, which has positive refractive power and satisfies the following relationship: R7×R8<0, and R7>R8, where R7 is the radius of curvature of the object side of the fourth lens, and R8 is the image side of the fourth lens The radius of curvature of; wherein, the four-piece imaging lens satisfies the following relationship: 0<F1/F3≦1.5, where F1 is the focal length value of the first lens, and F3 is the focal length value of the third lens. The four-piece imaging lens according to any one of claims 1 to 3, wherein the image side surface of the fourth lens element is convex. A four-piece imaging lens, from the object side to the image side, including: A first lens with negative refractive power, its image side surface is concave, and satisfies the following relationship: R1>R2, where R1 is the radius of curvature of the object side surface of the first lens, and R2 is the curvature of the image side surface of the first lens Radius; a second lens with positive refractive power, its object side is convex and its image side is flat or concave; an aperture; a third lens, with negative refractive power, its image side is concave, and satisfies the following relationship: R5 <R6, where R5 is the radius of curvature of the object side of the third lens, R6 is the radius of curvature of the image side of the third lens; and a fourth lens with positive refractive power, the image side of which is convex, and satisfies the following relationship Formula: R7>R8, where R7 is the radius of curvature of the object side of the fourth lens, and R8 is the radius of curvature of the image side of the fourth lens; wherein, the four-piece imaging lens satisfies the following relationship: 0< F1/F3≦1.5, where F1 is the focal length of the first lens, F3 is the focal length of the third lens; and (N2+N4)/2>1.8, where N2 is the refractive index of the second lens, and N4 Is the refractive index of the fourth lens. A four-piece imaging lens, from the object side to the image side, sequentially includes: a first lens with negative refractive power, the image side surface is concave, and satisfies the following relationship: R1>R2, where R1 is the first lens The curvature radius of the object side surface of the first lens, R2 is the curvature radius of the image side surface of the first lens; a second lens with positive refractive power, the object side surface is convex and the image side surface is flat or concave; an aperture; A third lens with negative refractive power, its image side is concave, and satisfies the following relationship: R5<R6, where R5 is the radius of curvature of the object side of the third lens, and R6 is the curvature of the image side of the third lens Radius; and a fourth lens with positive refractive power, its image side surface is convex, and satisfies the following relationship: R7>R8, where R7 is the radius of curvature of the object side surface of the fourth lens, and R8 is the image of the fourth lens The radius of curvature of the side surface; wherein, the four-piece imaging lens satisfies the following relationship: 0<F1/F3≦1.5, where F1 is the focal length value of the first lens, and F3 is the focal length value of the third lens; and -8<R4/R5<0, where R4 is the radius of curvature of the image side surface of the second lens, and R5 is the radius of curvature of the object side surface of the third lens. A four-piece imaging lens, from the object side to the image side, sequentially includes: a first lens with negative refractive power, the image side surface is concave, and satisfies the following relationship: R1>R2, where R1 is the first lens The radius of curvature of the object side of the lens, R2 is the radius of curvature of the image side of the first lens; a second lens with positive refractive power, the object side of which is convex and the image side of which is flat or concave; an aperture; a third lens , Has negative refractive power, its image side surface is concave, and satisfies the following relationship: R5<R6, where R5 is the radius of curvature of the object side surface of the third lens, and R6 is the radius of curvature of the image side surface of the third lens; and A fourth lens with positive refractive power, its image side surface is convex, and satisfies the following relationship: R7>R8, where R7 is the curvature radius of the object side surface of the fourth lens, and R8 is the curvature of the image side surface of the fourth lens Radius; where the four-piece imaging lens satisfies the following relationship: 0<F1/F3≦1.5, where F1 is the focal length value of the first lens, and F3 is the focal length value of the third lens; and 3<R4 /F<14, where R4 is the radius of curvature of the image side surface of the second lens, and F is the system focal length of the four-piece imaging lens.

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