TWI790968B - Eight-piece imaging lens - Google Patents

Abstract

The present invention provides an eight-piece imaging lens, which includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens in sequence from an object side to an image side lens. The first lens has negative refractive power, its object side is convex and its image side is concave. The object side of the second lens is concave. The third lens has positive refractive power and its object side is convex. The fourth lens has negative refractive power, and its object side and its image side are both concave. Both the object side and the image side of the fifth lens are convex. Both the object side and the image side of the sixth lens are convex. Both the object side and the image side of the seventh lens are concave. Both the object side and the image side of the eighth lens are 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, under the trend of improving system imaging quality, how to take into account manufacturability and reduce the impact of environmental changes on imaging quality is really worthy of consideration by those in the field.

The main purpose of the present invention is to provide an eight-piece imaging lens that can take into account manufacturability and reduce the impact of environmental changes on imaging quality.

In order to achieve the above and other objects, the present invention provides an eight-piece imaging lens, which includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens in sequence from the object side to the image side , the seventh lens and the eighth lens. The first lens has negative refractive power, its object side is convex and its image side is concave. The object side of the second lens is concave. The third lens has positive refractive power and its object side is convex. The fourth lens has negative refractive power, and its object side and image side are both concave. Both the object side and the image side of the fifth lens are convex. Both the object side and the image side of the sixth lens are convex. Both the object side and the image side of the seventh lens are concave. Both the object side and the image side of the eighth lens are convex. Through the combination of the above-mentioned refractive power and surface shape, high imaging quality can be achieved while taking into account the manufacturability, and the influence of environmental changes on the imaging quality can be reduced.

In order to achieve the above and other objectives, the present invention also provides an eight-piece imaging lens, which includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and lens, the seventh lens and the eighth lens. The first lens has negative refractive power, its object side is convex and its image side is concave. The object side of the second lens is concave. The third lens has positive refractive power and its object side is convex. The fourth lens has negative refractive power, and its object side and image side are both concave. The fifth, sixth and eighth lenses all have positive refractive power, and the seventh lens has negative refractive power. Through the combination of the aforementioned refractive power and surface shape, high imaging quality can be achieved while taking into account manufacturability, and the impact of environmental changes on imaging quality can be reduced.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: -40<(R1×R3)/T2<-30; where R1 is the radius of curvature of the object side of the first lens, R3 is the radius of curvature of the object side of the second lens, and T2 is the distance between the first and second lenses On-axis distance; through this, the viewing angle of the system can be increased through the surface matching of the first and second lenses.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: -39<(V6/V7)×R12<-22; wherein V6 is the dispersion coefficient of the sixth lens, V7 is the dispersion coefficient of the seventh lens, and R12 is the radius of curvature of the image side of the sixth lens; thereby, Through the material matching of the sixth and seventh lenses, chromatic aberration can be effectively reduced.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: -53<(R15*R16)/F8<-49; wherein 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; Therefore, by controlling the surface shape of the eighth lens, system distortion can be effectively corrected.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: -42<((F4×F5)/T8)/10<-20; where F4 is the focal length value of the fourth lens, F5 is the focal length value of the fifth lens, and T8 is the distance between the fourth and fifth lenses On-axis spacing; through this, the field curvature of the system can be effectively corrected by matching the refractive power of the fourth and fifth lenses.

As in the aforementioned eight-piece imaging lens, the following relationship can also be satisfied: 2<│((R5×R6)/T5)/100│<55; 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 T5 is the radius of curvature of the third lens On-axis thickness; thereby, by controlling the surface shape of the third lens, system astigmatism can be effectively corrected.

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.

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

The third lens 30 has positive refractive power, and its object side and image side are both convex.

The fourth lens 40 has negative refractive power, and its object side and image side are both concave. In this embodiment, the combination of the fourth lens 40 and the third lens 30 helps to balance aberrations.

The fifth lens 50 has positive refractive power, and its object side and image side are both convex, and the design of its image side being convex helps to correct aberrations.

The sixth lens 60 has positive refractive power, and its object side and image side are both convex, and the design of its image side being convex helps to correct spherical aberration.

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

The eighth lens 80 has positive refractive power, and its object side and image side are both convex, and the design of its object side being convex helps to correct distortion.

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, positive, negative, Positive, the refractive power configuration of each lens in the rear lens group is positive, negative, and positive in sequence. This combination helps to reduce aberrations, achieve high imaging quality and take into account manufacturability.

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 8.22mm, the system length is 42.12mm, the maximum viewing angle is 72.5∘, 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 17.98 0.70 1.77 49.60 -13.65 like side 2 6.58 4.56 second lens object side 3 -10.00 6.00 1.83 42.74 -130.67 like side 4 -14.02 0.10 third lens object side 5 16.55 2.68 1.86 22.73 15.06 like side 6 -61.87 4.41 fourth lens object side 7 -25.79 2.53 1.85 24.80 -11.69 like side 8 17.72 0.38 fifth lens object side 9 68.63 1.59 1.76 52.32 13.45 like side 10 -11.95 0.59 aperture ∞ -0.54 sixth lens object side 11 9.19 2.76 1.70 51.11 7.77 like side 12 -11.99 0.01 seventh lens object side 13 -11.99 3.34 1.89 20.36 -5.37 like side 14 9.49 3.70 eighth lens object side 15 18.99 2.22 1.96 17.47 12.57 like side 16 -34.12 0.10 flat lens object side 17 ∞ 1.00 like profile 18 ∞ 6.00

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

Table II Relational value (R1×R3)/T2 -39.42 (V6/V7) × R12 -30.09 (R15×R16)/F8 -51.55 ((F4×F5)/T8)/10 -41.38 │((R5×R6)/T5)/100│ 3.82

In this way, the eight-piece imaging lens of this embodiment can exhibit good imaging quality through the matching and combination of the lenses. 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 8.20mm, the system length is 42.13mm, the maximum viewing angle reaches 72.5∘, 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 17.24 3.55 1.77 49.58 -14.19 like side 2 6.14 4.86 second lens object side 3 -9.29 5.55 1.83 42.74 -87.95 like side 4 -13.51 0.07 third lens object side 5 16.66 2.51 1.86 22.73 15.17 like side 6 -62.85 4.40 fourth lens object side 7 -60.92 1.31 1.80 29.84 -10.20 like side 8 9.73 0.38 fifth lens object side 9 11.18 2.04 1.73 54.10 9.11 like side 10 -15.48 0.14 aperture ∞ -0.06 sixth lens object side 11 12.00 2.50 1.72 47.90 7.74 like side 12 -9.64 0.01 seventh lens object side 13 -9.64 4.44 1.89 20.36 -4.74 like side 14 9.70 3.00 eighth lens object side 15 17.06 2.44 1.96 17.47 11.70 like side 16 -33.70 0.10 flat lens object side 17 ∞ 1.00 like profile 18 ∞ 4.90

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

Table four Relational value (R1×R3)/T2 -32.92 (V6/V7) × R12 -22.67 (R15×R16)/F8 -49.10 ((F4×F5)/T8)/10 -24.38 │((R5×R6)/T5)/100│ 4.18

In this way, the eight-piece imaging lens of this embodiment can exhibit good imaging quality through the matching and combination of the lenses. 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, the one shown is the third embodiment of this creation, its lens configuration is roughly the same as that of the first embodiment, the main difference is that the second lens 20 has positive refractive power, and the image side of the third lens 30 is concave. 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 8.42mm, the system length is 48.35mm, the maximum viewing angle reaches 71.8∘, 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 19.41 1.54 1.65 56.24 -15.07 like side 2 6.35 7.39 second lens object side 3 -12.06 9.55 1.67 48.40 67.57 like side 4 12.58 0.52 third lens object side 5 11.34 2.95 1.86 22.73 15.92 like side 6 52.09 1.82 fourth lens object side 7 -64.15 1.26 1.85 23.79 -14.34 like side 8 15.57 0.72 fifth lens object side 9 45.69 2.16 1.70 51.11 16.16 like side 10 -14.95 -0.34 aperture ∞ 0.42 sixth lens object side 11 10.91 3.20 1.50 81.56 10.10 like side 12 -8.50 0.01 seventh lens object side 13 -8.50 4.06 1.92 18.90 -5.23 like side 14 14.78 2.65 eighth lens object side 15 22.06 2.71 1.95 17.99 12.94 like side 16 -27.79 0.10 flat lens object side 17 ∞ 1.00 like profile 18 ∞ 6.62

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

Table six Relational value (R1×R3)/T2 -31.66 (V6/V7) ×R12 -36.66 (R15×R16)/F8 -47.38 ((F4×F5)/T8)/10 -32.36 │((R5×R6)/T5)/100│ 2.00

In this way, the eight-piece imaging lens of this embodiment can exhibit good imaging quality through the matching and combination of the lenses. 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 shows the fourth embodiment of the invention, and its lens configuration is roughly the same as that of the first embodiment, the main difference is that the second lens 20 has positive refractive power. 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 8.37mm, the system length is 48.51mm, the maximum viewing angle reaches 71.8∘, 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 22.84 1.59 1.65 56.24 -15.02 like side 2 6.71 8.31 second lens object side 3 -12.32 8.57 1.67 48.40 73.73 like side 4 -12.64 1.63 third lens object side 5 10.82 3.29 1.86 22.73 12.21 like side 6 -1581.31 1.18 fourth lens object side 7 -31.61 1.34 1.85 23.79 -10.31 like side 8 12.72 0.71 fifth lens object side 9 39.79 2.10 1.70 51.11 14.40 like side 10 -13.39 -0.36 aperture ∞ 0.42 sixth lens object side 11 10.02 2.86 1.50 81.56 9.98 like side 12 -9.01 0.01 seventh lens object side 13 -9.01 3.60 1.92 18.90 -5.18 like side 14 13.03 3.81 eighth lens object side 15 20.46 2.61 1.95 17.99 13.46 like side 16 -34.46 0.10 flat lens object side 17 ∞ 1.00 like profile 18 ∞ 5.75

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

table eight Relational value (R1×R3)/T2 -33.87 (V6/V7) ×R12 -38.86 (R15×R16)/F8 -52.39 ((F4×F5)/T8)/10 -21.00 │((R5×R6)/T5)/100│ 52.08

In this way, the eight-piece imaging lens of this embodiment can exhibit good imaging quality through the matching and combination of the lenses. 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 (15)

An eight-piece imaging lens, which sequentially includes from the object side to the image side: A first lens with negative refractive power, its object side is convex and its image side is concave; a second lens whose object side is concave; a third lens with positive refractive power, and its object side is convex; 1. The fourth lens has negative refractive power, and its object side and image side are both concave; A fifth lens, the object side and the image side of which are both convex; - a sixth lens, the object side and the image side of which are both convex; - a seventh lens whose object side and image side are both concave; and One eighth eyeglass, its object side and its image side are both convex. The eight-chip imaging lens as described in claim 1 further satisfies the following relational formula: -40<(R1×R3)/T2<-30; where R1 is the radius of curvature of the object side of the first lens, R3 is the radius of curvature of the object side of the second lens, and T2 is the distance between the first and second lenses Axis spacing. The eight-chip imaging lens as described in claim 1 further satisfies the following relational formula: -39<(V6/V7)×R12<-22; where V6 is the dispersion coefficient of the sixth lens, V7 is the dispersion coefficient of the seventh lens, and R12 is the curvature radius of the image side of the sixth lens. The eight-chip imaging lens as described in claim 1 further satisfies the following relational formula: -53<(R15×R16)/F8<-49; 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. The eight-chip imaging lens as described in claim 1 further satisfies the following relational formula: -42<((F4×F5)/T8)/10<-20; where F4 is the focal length value of the fourth lens, F5 is the focal length value of the fifth lens, and T8 is the distance between the fourth and fifth lenses Axis spacing. The eight-chip imaging lens as described in claim 1 further satisfies the following relational formula: 2<│((R5×R6)/T5)/100│<55; 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 T5 is the radius of curvature of the third lens On-axis thickness. The eight-piece imaging lens as described in claim 1 further includes an aperture disposed between the fifth and sixth lenses. The eight-piece imaging lens according to claim 1, wherein the sixth and seventh lenses are cemented lenses. The eight-piece imaging lens according to claim 1, wherein the first to eighth lenses are all glass lenses. 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. An eight-piece imaging lens, which sequentially includes from the object side to the image side: A first lens with negative refractive power, its object side is convex and its image side is concave; a second lens whose object side is concave; a third lens with positive refractive power, and its object side is convex; 1. The fourth lens has negative refractive power, and its object side and image side are both concave; a fifth lens having positive refractive power; - a sixth lens with positive refractive power; a seventh lens having negative refractive power; and - an eighth lens having positive refractive power; Among them, the eight-piece imaging lens satisfies the following relationship: -40<(R1×R3)/T2<-30; where R1 is the radius of curvature of the object side of the first lens, R3 is the radius of curvature of the object side of the second lens, and T2 is the distance between the first and second lenses on-axis spacing; -42<((F4×F5)/T8)/10<-20; where F4 is the focal length value of the fourth lens, F5 is the focal length value of the fifth lens, and T8 is the distance between the fourth and fifth lenses on-axis spacing; and 2<│((R5×R6)/T5)/100│<55; 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 T5 is the radius of curvature of the third lens On-axis thickness. The eight-piece imaging lens as claimed in claim 11, wherein both the object side and the image side of the fifth lens are convex, and the object side and the image side of the sixth lens are both convex. The eight-piece imaging lens according to claim 11, wherein both the object side and the image side of the seventh lens are concave, and the object side and the image side of the eighth lens are convex. The eight-chip imaging lens as described in claim 11 further satisfies the following relational expression: -39<(V6/V7)×R12<-22; where V6 is the dispersion coefficient of the sixth lens, V7 is the dispersion coefficient of the seventh lens, and R12 is the curvature radius of the image side of the sixth lens. The eight-chip imaging lens as described in claim 11 further satisfies the following relational expression: -53<(R15×R16)/F8<-49; 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.

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