TWI804330B - Eight-piece imaging lens - Google Patents

Abstract

An eight-piece imaging lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a stop, a sixth lens, a seventh lens and an eighth lens in sequence from the object side to the image side . The first, second and third lenses all have negative refractive power. The fourth lens has positive refractive power, and both the object side and the image side are convex. The fifth lens has positive refractive power, its object side is concave and its image side is convex. The sixth lens has positive refractive power, and both the object side and the image side are convex. The seventh lens has negative refractive power, its object side is concave and its image side is convex. The eighth lens has negative refractive power, its object side is concave and its image side is convex.

Description

Eight-piece imaging lens

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

Optical lenses are widely used by people, and automotive lenses are also commonly used. Among them, how to achieve a large viewing angle while taking into account the imaging quality is really worthy of consideration by people in the field.

The main purpose of the present invention is to provide an eight-piece imaging lens capable of achieving a large viewing angle and taking into account the imaging quality.

In order to achieve the above and other objects, the present invention provides an eight-piece image-taking lens, which includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, an aperture, and a first lens from the object side to the image side. The sixth lens, the seventh lens and the eighth lens. The first, second and third lenses all have negative refractive power. The fourth lens has positive refractive power, and its object side and image side are both convex. The fifth lens has positive refractive power, its object side is concave and its image side is convex. The sixth lens has positive refractive power, and its object side and image side are both convex. The seventh lens has negative refractive power, its object side is concave and its image side is convex. The eighth lens has negative refractive power, its object side is concave and its image side is convex. In this way, the front lens group is composed of five lenses with negative, negative, negative, positive, and positive refractive powers, and the rear lens group is composed of three lenses with positive, negative, and negative refractive powers. Separated by apertures, this configuration of refractive power helps to reduce aberrations, achieve a large viewing angle and take into account the imaging quality.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: 40<F1×F2<50; where F1 is the focal length value of the first lens, and F2 is the focal length value of the second lens; thereby, Helps increase the maximum viewing angle of the system.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: 1.61<R5/R6<2; 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 ; Thereby, the system distortion can be corrected by controlling the surface shape of the third lens.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: 6<(V6/V7)×F6<7; where V6 is the dispersion coefficient of the sixth lens, V7 is the dispersion coefficient of the seventh lens, and F6 is the focal length value of the sixth lens; , The matching of the seventh lens material will help to correct the system chromatic aberration.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: -1.5<(R15×R16)/F8<0; where R15 is the radius of curvature of the object side of the eighth lens, R16 is the radius of curvature of the image side of the eighth lens, and F8 is the focal length of the eighth lens; thereby , the field curvature of the system can be corrected by controlling the surface shape and focal length of the eighth lens.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: -1.5<(R7+R8+R9+R10)/(F4+F5)<0; where R7 is the radius of curvature of the object side of the fourth lens, R8 is the radius of curvature of the image side of the fourth lens, and R9 is the radius of curvature of the fourth lens The radius of curvature of the object side of the fifth lens, R10 is the radius of curvature of the image side of the fifth lens, F4 is the focal length value of the fourth lens, and F5 is the focal length value of the fifth lens; The surface shape and focal length of the five lenses are matched to correct system astigmatism.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: 200<FOV<220; wherein FOV is the maximum viewing angle of the eight-piece imaging lens, thereby enhancing the wide viewing angle characteristic of the optical lens.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: 0.7<(R3-R4)/(R3+R4)<1; where R3 is the radius of curvature of the object side of the second lens, and R4 is the radius of curvature of the image side of the second lens; thereby, the second lens can be controlled surface to correct for astigmatism.

Please refer to FIG. 1, which shows the first embodiment of the present invention. The eight-piece imaging lens includes a first lens 10 and a second lens 20 on the optical axis L from the object side A to the image side B. , the third eyeglass 30, the fourth eyeglass 40, the fifth eyeglass 50, aperture ST, the sixth eyeglass 60, the seventh eyeglass 70 and the eighth eyeglass 80, are provided with CCD, CMOS or other photosensitive element (not shown) at image side B place As shown), a plate lens 90 such as a filter or protective glass can be provided between the photosensitive element and the eighth lens 80, and the number of the plate lens 90 can be increased or decreased or not provided according to requirements.

First of all, it should be stated 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 surface is a positive value; otherwise, when the center of a curved surface is closer to the surface itself On the object side, the radius of curvature of the surface is negative. And unless otherwise stated, the concave, convex and curvature radii of the "object side" and "image side" all refer to the surface shape and curvature radius 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 is convex and its image side is concave, and the design of its object side being convex helps to increase the maximum viewing angle of the system.

The second lens 20 has negative refractive power, and its object side is convex and its image side is concave. In this embodiment, the combination of the second lens 20 and the first lens 10 helps to correct distortion.

The third lens 30 has negative refractive power, its object side is convex and its image side is concave, so as to help correct aberrations.

The fourth lens 40 has positive refractive power, and its object side and image side are both convex.

The fifth lens 50 has positive refractive power, its object side is concave and its image side is convex. In this embodiment, the combination of the fifth lens 50 and the fourth lens 40 helps to correct astigmatism.

The sixth lens 60 has positive refractive power, and its object side and image side are both convex.

The seventh lens 70 has negative refractive power, its object side is concave and its image side is convex, and the sixth and seventh lenses 60 and 70 are cemented lenses, and the combination of the two helps to correct chromatic aberration.

The eighth lens 80 has negative refractive power, its object side is concave and its image side is convex, and the design of its object side being concave helps to correct field curvature.

In this embodiment, the object side and the image side of the first to eighth lenses are all spherical, and the first to eighth lenses are all glass lenses. And, with the aperture as the boundary, the first to fifth lenses form the front lens group, and the sixth to eighth lenses form the rear lens group, wherein the refractive power configuration of each lens in the front lens group is negative, negative, negative, positive, Positive, the refractive power configuration of each lens in the rear lens group is positive, negative, and negative in sequence. This combination helps to reduce aberrations, achieve a large viewing angle and take into account the imaging quality.

The design parameters of the eight-piece imaging lens of this embodiment are shown in Table 1 below. 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. The distance between the lens and the next lens or the next aperture ST on the optical axis L:

Table I first embodiment The system focal length F is 1.4mm, the system length is 19.95mm, the maximum viewing angle is 218.2∘, and the aperture value is 2 lens noodle Radius of curvature (mm) Distance (mm) Refractive index (Nd) Dispersion coefficient (Vd) focal length(mm) first lens object side 1 11.47 0.71 1.65 56.24 -12.51 like side 2 4.67 2.30 second lens object side 3 32.62 0.70 1.80 46.58 -3.65 like side 4 2.69 0.95 third lens object side 5 4.43 0.64 1.75 52.31 -11.30 like side 6 2.74 0.62 fourth lens object side 7 7.74 2.65 1.95 17.94 4.64 like side 8 -9.07 0.31 fifth lens object side 9 -5.60 3.28 1.88 40.13 9.46 like side 10 -4.30 0.06 aperture ∞ -0.01 sixth lens object side 11 0.04 1.83 1.75 52.31 2.21 like side 12 -1.89 0.01 seventh lens object side 13 -1.89 1.96 1.95 17.99 -9.85 like side 14 -3.56 0.07 eighth lens object side 15 -3.51 0.26 1.77 49.58 -17.06 like side 16 -4.92 0.44 flat lens object side 17 ∞ 0.51 like profile 18 ∞ 2.67

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

Table II Relational value F1×F2 45.60 R5/R6 1.61 (V6/V7)×F6 6.43 (R15×R16)/F8 -1.01 (R7+R8+R9+R10)/(F4+F5) -0.81 FOV 218.2 (R3-R4)/(R3+R4) 0.85

In this way, through the collocation and combination of lenses, the eight-piece imaging lens of this embodiment can exhibit good imaging quality. The field curvature and distortion diagrams can be seen in Figs. 2 and 3. It is obvious that this embodiment has a good imaging effect.

Please refer to Figure 4, which shows the second embodiment of this invention, and its lens configuration is roughly the same as that of the first embodiment. The design parameters of the eight-piece imaging lens of this embodiment are shown in Table 3 below:

Table three second embodiment The system focal length F is 1.39mm, the system length is 20.29mm, the maximum viewing angle is 210∘, and the aperture value is 2.06 lens noodle Radius of curvature (mm) Distance (mm) Refractive index (Nd) Dispersion coefficient (Vd) focal length(mm) first lens object side 1 12.08 0.79 1.65 56.24 -12.96 like side 2 4.87 2.34 second lens object side 3 33.05 0.78 1.80 46.58 -3.75 like side 4 2.77 0.98 third lens object side 5 4.44 0.69 1.75 52.31 -11.19 like side 6 2.72 0.75 fourth lens object side 7 8.29 3.13 1.95 17.94 4.98 like side 8 -9.57 0.32 fifth lens object side 9 -5.89 2.65 1.88 40.13 9.88 like side 10 -4.28 0.30 aperture ∞ -0.01 sixth lens object side 11 10.80 1.46 1.75 52.31 2.12 like side 12 -1.79 0.01 seventh lens object side 13 -1.79 1.73 1.95 17.99 -8.40 like side 14 -3.38 0.13 eighth lens object side 15 -3.12 0.58 1.77 49.58 -21.96 like side 16 -4.19 0.44 flat lens object side 17 ∞ 0.30 like profile 18 ∞ 2.91

According to Table 3, the following relational values in Table 4 can be obtained:

Table four Relational value F1×F2 45.58 R5/R6 1.63 (V6/V7)×F6 6.16 (R15×R16)/F8 -0.60 (R7+R8+R9+R10)/(F4+F5) -0.77 FOV 210 (R3-R4)/(R3+R4) 0.85

In this way, through the collocation and combination of lenses, the eight-piece imaging lens of this embodiment can exhibit good imaging quality. The field curvature and distortion diagrams can be seen in Figs. 5 and 6, which shows that this embodiment has a good imaging effect.

Please refer to Fig. 7, which is the third embodiment of the invention, and its lens configuration is roughly the same as that of the first embodiment. The design parameters of the eight-chip imaging lens of this embodiment are shown in Table 5 below:

Table five third embodiment The system focal length F is 1.41mm, the system length is 19.9mm, the maximum viewing angle is 214∘, and the aperture value is 2 lens noodle Radius of curvature (mm) Distance (mm) Refractive index (Nd) Dispersion coefficient (Vd) focal length(mm) first lens object side 1 11.39 0.71 1.65 56.24 -12.05 like side 2 4.56 2.27 second lens object side 3 34.58 0.71 1.80 46.58 -3.47 like side 4 2.59 1.19 third lens object side 5 6.17 0.66 1.75 52.31 -9.91 like side 6 3.24 0.38 fourth lens object side 7 6.31 2.09 1.95 17.94 4.24 like side 8 -10.07 0.37 fifth lens object side 9 -5.73 3.59 1.88 40.13 9.79 like side 10 -4.49 0.09 aperture ∞ -0.04 sixth lens object side 11 9.37 1.80 1.75 52.31 2.23 like side 12 -1.91 0.01 seventh lens object side 13 -1.91 1.99 1.95 17.99 -11.14 like side 14 -3.51 0.10 eighth lens object side 15 -3.33 0.22 1.77 49.58 -16.78 like side 16 -4.59 0.44 flat lens object side 17 ∞ 0.51 like profile 18 ∞ 2.81

According to Table 5, the relational values in the following Table 6 can be obtained:

Table six Relational value F1×F2 41.84 R5/R6 1.90 (V6/V7)×F6 6.49 (R15×R16)/F8 -0.91 (R7+R8+R9+R10)/(F4+F5) -1.00 FOV 214 (R3-R4)/(R3+R4) 0.86

In this way, through the collocation and combination of lenses, the eight-piece imaging lens of this embodiment can exhibit good imaging quality. The field curvature and distortion diagrams can be seen in Figs. 8 and 9, which shows that this embodiment has a good imaging effect.

Please refer to Fig. 10, which is the fourth embodiment of the invention, and its lens configuration is roughly the same as that of the first embodiment. The design parameters of the eight-chip imaging lens of this embodiment are shown in Table 7 below:

Table Seven Fourth embodiment The system focal length F is 1.41mm, the system length is 19.89mm, the maximum viewing angle is 214∘, and the aperture value is 2 lens noodle Radius of curvature (mm) Distance (mm) Refractive index (Nd) Dispersion coefficient (Vd) focal length(mm) first lens object side 1 11.41 0.71 1.65 56.24 -11.99 like side 2 4.55 2.29 second lens object side 3 31.85 0.70 1.80 46.58 -3.48 like side 4 2.58 1.19 third lens object side 5 6.04 0.65 1.75 52.31 -9.86 like side 6 3.19 0.38 fourth lens object side 7 6.29 2.55 1.95 17.94 4.39 like side 8 -10.78 0.37 fifth lens object side 9 -5.84 3.14 1.88 40.13 9.57 like side 10 -4.35 0.09 aperture ∞ -0.04 sixth lens object side 11 0.41 1.80 1.75 52.31 2.21 like side 12 -1.89 0.01 seventh lens object side 13 -1.89 1.99 1.95 17.99 -10.68 like side 14 -3.51 0.09 eighth lens object side 15 -3.36 0.21 1.77 49.58 -17.07 like side 16 -4.61 0.44 flat lens object side 17 ∞ 0.51 like profile 18 ∞ 2.80

According to Table 7, the value of the relational expression in the following Table 8 can be obtained:

table eight Relational value F1×F2 41.71 R5/R6 1.89 (V6/V7)×F6 6.43 (R15×R16)/F8 -0.91 (R7+R8+R9+R10)/(F4+F5) -1.05 FOV 214 (R3-R4)/(R3+R4) 0.85

In this way, through the collocation and combination of lenses, the eight-piece imaging lens of this embodiment can exhibit good imaging quality. The field curvature and distortion diagrams can be seen in Figs. 11 and 12, which shows that this embodiment has a good imaging effect.

10: First lens 20: second lens 30: Third lens 40: Fourth lens 50: fifth lens 60: sixth lens 70: seventh lens 80: eighth lens 90: flat lens A: Object side B: image side ST: Aperture L: optical axis

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

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

Fig. 3 is a distortion map of the first embodiment of the present invention.

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

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

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

Fig. 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.

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

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

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

Fig. 12 is a distortion map of the fourth embodiment of the present invention.

10: First lens

20: second lens

30: Third lens

40: Fourth lens

50: fifth lens

60: sixth lens

70: seventh lens

80: eighth lens

90: flat lens

A: Object side

B: image side

ST: Aperture

L: optical axis

Claims (12)

An eight-piece imaging lens, comprising in sequence from the object side to the image side: a first lens with negative refractive power; a second lens with negative refractive power; a third lens with negative refractive power; a fourth lens with negative refractive power. It has positive refractive power, and its object side and image side are both convex; a fifth lens has positive refractive power, its object side is concave and its image side is convex; The side surface and its image side are both convex; a seventh lens with negative power, its object side is concave and its image side is convex; and an eighth lens has negative power, its object side is concave and its image side is Convex surface; wherein, the eight-piece imaging lens further satisfies the following relationship: 40<F1×F2<50; wherein F1 is the focal length value of the first lens, and F2 is the focal length value of the second lens. The eight-piece imaging lens as described in Claim 1 further satisfies the following relationship: 1.61<R5/R6<2; 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 radius of curvature. The eight-chip imaging lens as described in Claim 1 further satisfies the following relationship: 6<(V6/V7)×F6<7; where V6 is the dispersion coefficient of the sixth lens, and V7 is the dispersion coefficient of the seventh lens Dispersion coefficient, F6 is the focal length value of the sixth lens. The eight-piece imaging lens as described in Claim 1 further satisfies the following relationship: -1.5<(R15×R16)/F8<0; wherein R15 is the radius of curvature of the object side of the eighth lens, and R16 is the radius of curvature of the eighth lens. The radius of curvature of the image side of the eighth lens, F8 is the focal length value of the eighth lens. The eight-piece imaging lens as described in claim 1 further satisfies the following relationship: -1.5<(R7+R8+R9+R10)/(F4+F5)<0; wherein R7 is the object side of the fourth lens R8 is the radius of curvature of the image side of the fourth lens, R9 is the radius of curvature of the object side of the fifth lens, R10 is the radius of curvature of the image side of the fifth lens, F4 is the focal length of the fourth lens, F5 is the focal length value of the fifth lens. The eight-piece imaging lens as described in Claim 1 further satisfies the following relationship: 200<FOV<220; wherein FOV is the maximum viewing angle of the eight-piece imaging lens. The eight-piece imaging lens as described in claim 1 further satisfies the following relationship: 0.7<(R3-R4)/(R3+R4)<1; where R3 is the radius of curvature of the object side of the second lens, and R4 is the radius of curvature of the image side of the second lens. The eight-piece imaging lens according to claim 1, wherein the object side of the first lens is convex and the image side is concave. The eight-piece imaging lens according to claim 1, wherein the object side of the second lens is convex and the image side is concave. The eight-piece imaging lens according to claim 1, wherein the object side of the third lens is convex and the image side is concave. The eight-piece imaging lens according to claim 1, wherein the object side and the image side of the first to eighth lenses are all spherical, and the first to eighth lenses are all glass lenses. The eight-piece imaging lens according to claim 1, wherein the sixth and seventh lenses are cemented lenses.

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