wide-angle lens

Abstract

The present invention provides a wide-angle lens comprising, in order from the object side to the image side, a first lens element on the optical axis, which is a lens with negative refractive power and a concave image-side surface; a second lens element, which is a lens with negative refractive power and a concave image-side surface; a third lens element, which is a lens with negative refractive power; a fourth lens element, which is a lens with positive refractive power; a fifth lens element, which is a lens with refractive power; a sixth lens element, which is a lens with positive refractive power and a convex object-side surface and a convex image-side surface; a seventh lens element, which is a lens with negative refractive power; and an eighth lens element, which is a lens with positive refractive power and a convex object-side surface and a convex image-side surface. The wide-angle lens has the characteristics of being compact, having good resolution, and being environmentally resistant.

Description

Technical Field

[0001] The present invention relates to an optical component, and in particular to a wide-angle lens. Background Art

[0002] In recent years, imaging equipment has gained widespread application, with specifications becoming increasingly diverse in response to diverse application requirements. In particular, market demand for wide-angle lenses with a wide field of view continues to increase. Furthermore, miniaturization and high resolution are also key development trends for these lenses. Furthermore, to ensure consistent performance in diverse environments, wide-angle lenses must be resistant to environmental fluctuations, ensuring high performance in both high and low temperatures. Therefore, the market urgently needs lenses that offer a wide field of view, miniaturization, high image quality, and high environmental tolerance. Applications for these lenses include automotive cameras, surveillance cameras, drones, sports photography equipment, head-mounted cameras, and various electronic products equipped with lenses. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a wide-angle lens with the characteristics of miniaturization, good resolution and good environmental tolerance, in view of the above-mentioned defects of the prior art.

[0004] The present invention provides a technical solution for solving the technical problem. On the one hand, it provides a wide-angle lens, which comprises, in order from the object side to the image side on the optical axis: a first lens having negative refractive power, whose image-side surface is concave; a second lens having negative refractive power, whose image-side surface is concave; a third lens having negative refractive power; a fourth lens having positive refractive power; a fifth lens having refractive power; a sixth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; a seventh lens having negative refractive power; and an eighth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex. The wide-angle lens satisfies the following condition: 21.02≦f4+f6≦26.89, where f4 is the effective focal length of the fourth lens and f6 is the effective focal length of the sixth lens.

[0005] Another aspect of the present invention provides a wide-angle lens comprising, in order from the object side to the image side on the optical axis: a first lens having negative refractive power, whose image-side surface is concave; a second lens having negative refractive power, whose image-side surface is concave; a third lens having negative refractive power; a fourth lens having positive refractive power; a fifth lens having refractive power; a sixth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; a seventh lens having negative refractive power; and an eighth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex. The wide-angle lens satisfies the following condition: 18.66≦f4+f8≦23.13, where f4 is the effective focal length of the fourth lens and f8 is the effective focal length of the eighth lens.

[0006] In the wide-angle lens of the present invention, the object-side surface of the third lens is concave, the image-side surface of the fifth lens is convex, and the image-side surface of the seventh lens is concave.

[0007] In the wide-angle lens of the present invention, the image-side surface of the third lens is concave, and the object-side surface of the seventh lens is convex.

[0008] In the wide-angle lens of the present invention, the image-side surface of the third lens is convex, and the object-side surface of the fifth lens is concave.

[0009] In the wide-angle lens of the present invention, the image-side surface of the third lens is convex, and the object-side surface of the seventh lens is concave.

[0010] In the wide-angle lens of the present invention, the object-side surface of the fifth lens is a convex surface.

[0011] The wide-angle lens of the present invention further includes an aperture, which is disposed between two adjacent lenses among the first to eighth lenses. The lens disposed along the aperture toward the object side is a lens located in front of the aperture, and the lens disposed along the aperture toward the image side is a lens located behind the aperture. The lens located in front of the aperture includes at least one lens, and the lens located behind the aperture includes at least one lens.

[0012] In the wide-angle lens of the present invention, the wide-angle lens satisfies at least one of the following conditions: -0.64≦(G7R2+G6R2) / GAR1≦-0.03; -5≦(GBR1+G6R2) / G7R2≦16; -50≦GBR2+G3R2≦28; -0.72≦G7R2 / VB≦2.15; wherein GAR1 is the curvature of the object side surface of the first lens before the aperture. GBR1 is the curvature radius of the object-side surface of the first lens after the aperture, GBR2 is the curvature radius of the image-side surface of the first lens after the aperture, G3R2 is the curvature radius of the image-side surface of the third lens, G6R2 is the curvature radius of the image-side surface of the sixth lens, G7R2 is the curvature radius of the image-side surface of the seventh lens, and VB is the Abbe coefficient of the first lens after the aperture.

[0013] In the wide-angle lens of the present invention, the wide-angle lens satisfies at least one of the following conditions: -25.66≦f4+f3≦-5.19; -0.06≦(G7R1 / G3R2) / G5R1≦0.12; -1.29≦(G7R2-G6R2) / f3≦-0.62; wherein f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, G3R2 is the curvature radius of the image-side surface of the third lens, G5R1 is the curvature radius of the object-side surface of the fifth lens, G6R2 is the curvature radius of the image-side surface of the sixth lens, G7R1 is the curvature radius of the object-side surface of the seventh lens, and G7R2 is the curvature radius of the image-side surface of the seventh lens.

[0014] The wide-angle lens of the present invention further includes a ninth lens disposed between the first lens and the third lens. The ninth lens has negative refractive power, and its object-side surface is convex and its image-side surface is concave.

[0015] The wide-angle lens of the present invention has the characteristics of miniaturization, good resolution, and excellent environmental tolerance. It also has the advantages of small field curvature and good magnification chromatic aberration. Therefore, the wide-angle lens of the present invention meets the requirements of high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram showing a wide-angle lens according to the present invention.

[0017] Figure 2A 、 2B 2C and 2D show a schematic diagram, a field curvature diagram, a distortion diagram, and a longitudinal chromatic aberration diagram of the wide-angle lens according to the first embodiment of the present invention.

[0018] Figure 3A 、 3B 3C and 3D show a schematic diagram, a field curvature diagram, a distortion diagram, and a longitudinal chromatic aberration diagram of a wide-angle lens according to the second embodiment of the present invention.

[0019] Figure 4A 、 4B 4C and 4D are schematic diagrams, field curvature diagrams, distortion diagrams, and longitudinal chromatic aberration diagrams of a wide-angle lens according to a third embodiment of the present invention.

[0020] Figure 5A 、 5B 5C and 5D are schematic diagrams, field curvature diagrams, distortion diagrams, and longitudinal chromatic aberration diagrams of a wide-angle lens according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the above and other objects, features and advantages of the present invention more clearly understood, preferred embodiments of the present invention will be specifically described below in detail with reference to the accompanying drawings.

[0022] The present invention provides a wide-angle lens with advantages such as minimal image plane curvature and excellent lateral chromatic aberration. It can meet the requirements of a large field of view, miniaturization, high imaging quality, and high environmental tolerance. It can be applied to vehicle-mounted lenses, monitors, drones, sports photography equipment, head-mounted cameras, and various electronic products equipped with lenses.

[0023] Figure 1 A schematic diagram showing a wide-angle lens according to the present invention is shown. Figure 1 As shown, the wide-angle lens of the present invention includes two lens groups: a first lens group located in front of the aperture STO and a second lens group located behind the aperture STO. In one exemplary embodiment, the first lens group includes, in order from the object side to the image side along the optical axis OA, a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. The second lens group includes, in order from the object side to the image side along the optical axis OA, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8. However, this is not limiting. The first and second lens groups may each include other numbers of lenses, for example, the first lens group includes five lenses and the second lens group includes four lenses. Light from the object side passes through the first lens group, the aperture STO, and the second lens group, and is imaged on the imaging plane IMA. A protective glass (not shown) may be provided between the second lens group and the imaging plane IMA. This protective glass may be a filter. In one exemplary embodiment, the wide-angle lens has a single focus and is a fixed-focus optical system.

[0024] In terms of lens composition, in the first lens group, the first lens L1 is a lens with negative refractive power, such as a meniscus lens, with its image-side surface being concave. The second lens L2 is a lens with negative refractive power, such as a meniscus lens, with its image-side surface being concave. The third lens L3 is a lens with negative refractive power, such as a biconcave lens or a meniscus lens. The fourth lens L4 is a lens with positive refractive power, such as a biconvex lens. In the second lens group, the fifth lens L5 is a lens with refractive power, such as a lens with positive refractive power (such as a biconvex lens or a meniscus lens). The sixth lens L6 is a lens with positive refractive power, such as a biconvex lens, with its object-side surface and image-side surface being convex. The seventh lens L7 is a lens with negative refractive power, such as a biconcave lens or a meniscus lens. The eighth lens L8 is a lens with positive refractive power, such as a biconvex lens, with its object-side surface and image-side surface being convex. In the wide-angle lens of the present invention, the refractive powers of the first to eighth lenses L1-L8 are, in order, negative, negative, negative, positive, positive, positive, negative, and positive. Furthermore, a ninth lens (see the fourth embodiment) can be positioned between the first lens L1 and the third lens L3 of the first lens group (specifically, between the first lens L1 and the second lens L2), such that the refractive powers of the wide-angle lens from left to right are, in order, negative, negative, negative, negative, positive, positive, positive, negative, and positive. This optical lens has a field of view of up to 222 degrees, and the total length can be designed to be approximately 20 to 35 mm, meeting the requirements of a wide field of view and miniaturization. Furthermore, most or all of the lenses can be made of temperature-resistant glass, offering excellent environmental tolerance.

[0025] In order to enable the wide-angle lens of the present invention to maintain good optical performance, the wide-angle lens of the present invention may further satisfy the following conditional formula (1):

[0026] 21.02≦f4+f6≦26.89,

[0027] Where f4 is the effective focal length of the fourth lens, and f6 is the effective focal length of the sixth lens. Conditional equation (1) controls the focal lengths of the fourth lens L4 and the sixth lens L6, thereby converging light, helping to reduce the angle of the principal ray on the imaging plane IMA and increase the amount of peripheral light. Wide-angle lenses that meet conditional equation (1) have excellent imaging performance and high image quality.

[0028] In order to enable the wide-angle lens of the present invention to maintain good optical performance, the wide-angle lens of the present invention may further satisfy the following conditional formula (2):

[0029] 18.66≦f4+f8≦23.13,

[0030] Where f4 is the effective focal length of the fourth lens, and f8 is the effective focal length of the eighth lens. Conditional equation (2) controls the focal lengths of the fourth lens L4 and the eighth lens L8, thereby converging light, helping to reduce the angle of the principal ray on the imaging plane IMA and increase the amount of peripheral light. Wide-angle lenses that meet conditional equation (2) have excellent imaging performance and high image quality.

[0031] In one embodiment, the object-side surface of both the first lens element L1 and the object-side surface of the second lens element L2 are convex. The design of the first lens element L1 with negative refractive power and its convex object-side surface facilitates the formation of a retrofocus lens structure, allowing light from a wide viewing angle to enter the optical system. The design of the second lens element L2 with negative refractive power distributes the negative refractive power of the first lens element L1, and its convex object-side surface facilitates aberration correction.

[0032] In one embodiment, both the object-side surface and the image-side surface of the fourth lens element L4 are convex. That is, the fourth lens element L4 is a biconvex lens, which can provide the system's primary light-converging capability and help shorten the overall lens length.

[0033] In one embodiment, the object-side surface of the third lens element L3 is concave, the image-side surface of the fifth lens element L5 is convex, and the image-side surface of the seventh lens element L7 is concave. The third lens element L3 is designed to have negative refractive power, and its object-side surface is concave, which helps to smooth light at wide viewing angles. The fifth lens element L5 is designed to have positive refractive power, and its image-side surface is convex, which helps to enhance the short focal length characteristics of the wide-angle system. In one embodiment, the third lens element L3 is a biconcave lens, and the seventh lens element L7 is a meniscus lens, with the image-side surface of the third lens L3 being concave and the object-side surface of the seventh lens L7 being convex. In one embodiment, the third lens element L3 is a meniscus lens with negative refractive power, and the fifth lens element L5 is a meniscus lens with positive refractive power. The image-side surface of the third lens L3 is convex, and the object-side surface of the fifth lens L5 is concave. In one embodiment, the third lens element L3 is a meniscus lens, and the seventh lens element L7 is a biconcave lens. The image-side surface of the third lens element L3 is convex, and the object-side surface of the seventh lens element L7 is concave. In one embodiment, the fifth lens element L5 is a biconvex lens, and the object-side surface of the fifth lens element L5 is convex.

[0034] In one embodiment, the wide-angle lens of the present invention can satisfy the following condition (3) to further maintain optical performance:

[0035] -25.66≦f4+f3≦-5.19,

[0036] Where f3 is the effective focal length of the third lens L3, and f4 is the effective focal length of the fourth lens L4. Conditional equation (3) controls the focal lengths of the third lens L3 and the fourth lens L4, helping to improve imaging quality. A wide-angle lens that meets condition (3) exhibits minimal image curvature, with no excessive distortion when the image field is projected onto the imaging plane. It also exhibits excellent lateral chromatic aberration, with the magnification increase not significantly affecting color shift. This range ensures optimal achromatic and anti-image distortion conditions.

[0037] In one embodiment, the wide-angle lens of the present invention can satisfy the following condition (4) to further maintain optical performance:

[0038] -1.29≦(G7R2-G6R2) / f3≦-0.62,

[0039] Wherein f3 is the effective focal length of the third lens L3, G6R2 is the radius of curvature of the image side surface of the sixth lens L6, and G7R2 is the radius of curvature of the image side surface of the seventh lens L7. Conditional formula (4) can control the focal length of the third lens L3 and the radius of curvature of the image side surfaces of the sixth lens L6 and the seventh lens L7, which helps to improve the imaging quality. The wide-angle lens that meets condition (4) has a small degree of image curvature, the image field will not be excessively distorted when projected on the imaging plane IMA, and the magnification chromatic aberration is good. The increase in magnification will not excessively affect the color deviation. If it meets this range, it has the best achromatic and anti-image distortion conditions. In one embodiment, the wide-angle lens of the present invention can meet the following conditional formula (5) to further maintain the optical performance:

[0040] -0.06≦(G7R1 / G3R2) / G5R1≦0.12,

[0041] Where G3R2 is the radius of curvature of the image-side surface of the third lens element L3, G5R1 is the radius of curvature of the object-side surface of the fifth lens element L5, and G7R1 is the radius of curvature of the object-side surface of the seventh lens element L7. This can further correct lateral chromatic aberration and distortion, improving image quality. Meeting this range achieves optimal achromatism and anti-image distortion.

[0042] In one embodiment, the aperture STO is disposed between two adjacent lenses among the first to eighth lenses L1-L8. In the present invention, the lens disposed toward the object side of the aperture STO is defined as the lens located in front of the aperture STO, i.e., the lens in the first lens group, while the lens disposed toward the image side of the aperture STO is defined as the lens located behind the aperture STO, i.e., the lens in the second lens group. The first lens group and the second lens group each include at least one lens, i.e., the lens located in front of the aperture STO includes at least one lens, and the lens located behind the aperture STO includes at least one lens.

[0043] In one embodiment, the wide-angle lens of the present invention can satisfy the following conditional equation (6) to further maintain optical performance:

[0044] -5≦(GBR1+G6R2) / G7R2≦16,

[0045] Among them, GBR1 is the first lens after the aperture STO (for example Figure 1 G6R2 is the radius of curvature of the object-side surface of the fifth lens element L5, G6R2 is the radius of curvature of the image-side surface of the sixth lens element L6, and G7R2 is the radius of curvature of the image-side surface of the seventh lens element L7. This further corrects field curvature, ensuring that the image field is projected onto the imaging plane IMA without excessive distortion. Meeting this range demonstrates optimal anti-image distortion conditions.

[0046] In one embodiment, the wide-angle lens of the present invention can satisfy the following conditional equation (7) to further maintain optical performance:

[0047] -0.64≦(G7R2+G6R2) / GAR1≦-0.03,

[0048] GAR1 is the first lens in front of the aperture STO (for example Figure 1 G6R2 is the radius of curvature of the object-side surface of the fourth lens element L4, G6R2 is the radius of curvature of the image-side surface of the sixth lens element L6, and G7R2 is the radius of curvature of the image-side surface of the seventh lens element L7. This further corrects lateral chromatic aberration and distortion, improving image quality. A lens within this range achieves optimal achromatism and image distortion resistance.

[0049] In one embodiment, the wide-angle lens of the present invention can satisfy the following conditional equation (8) to further maintain optical performance:

[0050] -0.72≦G7R2 / VB≦2.15,

[0051] Where VB is the first lens after the aperture STO (for example Figure 1 G7R2 is the radius of curvature of the image-side surface of the seventh lens L7. This allows correction of longitudinal chromatic aberration, and meeting this range provides optimal achromatic conditions.

[0052] In one embodiment, the wide-angle lens of the present invention can satisfy the following conditional equation (9) to further maintain optical performance:

[0053] -50≦GBR2+G3R2≦28,

[0054] GBR2 is the first lens after the aperture (e.g. Figure 1G3R2 is the radius of curvature of the image-side surface of the fifth lens element L5, and G3R3 is the radius of curvature of the image-side surface of the third lens element L3. This allows for correction of spherical aberration, and optimal spherical aberration performance is achieved when this range is met.

[0055] In one embodiment, the first lens group of the wide-angle lens of the present invention includes at least three concave lenses. For example, at least three of the first through eighth lenses L1-L8 are located in front of the aperture STO and are concave lenses. This helps correct longitudinal chromatic aberration.

[0056] In one embodiment, the second lens group of the wide-angle lens of the present invention includes at least three convex lenses. At least three of the first through eighth lenses L1-L8 are located behind the aperture STO and are convex lenses. This helps correct spherical aberration.

[0057] In one embodiment, the wide-angle lens of the present invention includes at least one aspherical lens. For example, at least one of the first through eighth lenses L1-L8 is an aspherical lens. This effectively reduces the overall length of the wide-angle lens while still meeting the requirements for capturing distant images.

[0058] The object-side and image-side surfaces of each lens element L1-L8 in the wide-angle lens of the present invention can be aspherical. Aspherical surfaces provide a greater degree of controllability, thereby reducing aberrations. However, some lenses can also be plastic, reducing costs while maintaining excellent resolution. Of course, these lenses can also be implemented as composite lenses composed of plastic or glass, consisting of two lenses bonded together with no air space between them.

[0059] The shape of an aspheric lens can be expressed as follows:

[0060]

[0061] Where D represents the sag of the aspheric lens at a relative height from the central axis of the lens, C represents the inverse of the paraxial curvature radius, H represents the relative height of the aspheric lens from the central axis of the lens, K represents the conic constant of the aspheric lens, and E4 to E12 represent the aspheric correction coefficients of even orders above the fourth order, and E in the coefficient represents the scientific notation, such as E-03 represents 10 -3 .

[0062] The wide-angle lens of the present invention will be further described in detail with reference to specific embodiments below.

[0063] First embodiment:

[0064] See also Figures 2A to 2D ,in Figure 2AA schematic diagram showing a wide-angle lens according to a first embodiment of the present invention is shown. Figures 2B to 2D The distortion, field curvature and longitudinal chromatic aberration diagrams of the first embodiment are shown in order. The wavelength of light used in the measurement process is 0.555 μm. Figure 2A In the wide-angle lens of the first embodiment of the present invention, the first lens group located in front of the aperture STO is a structure with four lenses (i.e., L1 to L4), and the second lens group located behind the aperture STO is also a structure with four lenses (i.e., L1 to L4). In the first lens group, the first lens L1 and the second lens L2 are both meniscus lenses, specifically convex-concave lenses, that is, the image side surfaces of the first lens L1 and the second lens L2 are both concave. The third lens L3 is a biconcave lens, and the fourth lens L4 is a biconvex lens. The first lens group has three concave lenses, which helps to correct longitudinal chromatic aberration. In the second lens group, the fifth lens L5, the sixth lens L6 and the eighth lens L8 are all biconvex lenses, and the seventh lens L7 is a meniscus lens, specifically a convex-concave lens, that is, its image side surface is concave. The third lens group has three convex lenses, which helps to correct spherical aberration.

[0065] Table 1 shows the relevant parameters of the wide-angle lens and its various lenses, and Table 2 shows the relevant parameters of the aspherical surfaces in Table 1. As can be seen from Table 2, the fourth lens L4 and the eighth lens L8 are aspherical lenses.

[0066]

[0067] Table 1

[0068] Face number K E4 E6 E8 E10 S7 9.64E-04 3.28E-05 2.38E-06 -3.4E-07 S8 2.10E-03 9.19E-05 -7.25E-06 8.53E-07 S16 -3.37E-04 1.53E-05 -3.23E-08 S17 1.883 1.62E-04 8.16E-06 2.60E-07

[0069] Table 2

[0070] Table 3 shows the parameters of the wide-angle lens of the first embodiment related to the above-mentioned conditional expressions (1) to (9).

[0071]

[0072] Table 3

[0073] Table 4 shows the values ​​calculated according to equations (1) to (9) for the wide-angle lens of the first embodiment of the present invention. As can be seen from Table 4, the wide-angle lens of the first embodiment meets the requirements of equations (1) to (9).

[0074]

[0075] Table 4

[0076] In addition, the optical performance of the wide-angle lens of the first embodiment can also meet the requirements. Figure 2B It can be seen that the field curvature is between -0.03mm and 0.005mm. Figure 2CIt can be seen that the distortion is between -3% and 0%, Figure 2D It can be seen that the longitudinal chromatic aberration ranges from -0.003mm to 0.012mm. Clearly, the field curvature, distortion, and longitudinal chromatic aberration of the wide-angle lens of the first embodiment are effectively corrected, resulting in excellent resolution.

[0077] Second embodiment:

[0078] See also Figures 3A to 3D ,in Figure 3A A schematic diagram showing a wide-angle lens according to a second embodiment of the present invention is shown. Figures 3B to 3D The distortion, field curvature and longitudinal chromatic aberration diagrams of the second embodiment are shown in order. The wavelength of light used in the measurement process is 0.555 μm. Figure 3A Unlike the first embodiment, in the wide-angle lens of the second embodiment of the present invention, the third lens element L3 and the fifth lens element L5 are meniscus lenses, specifically, concave-convex lenses, and the seventh lens element L7 is a biconcave lens. Similar to the first embodiment, the first lens group and the second lens group each have three concave lenses and three convex lenses, respectively.

[0079] Table 5 is a table of relevant parameters of the wide-angle lens and its various lenses, and Table 6 is a table of relevant parameters of the aspherical surfaces in Table 5. As can be seen from Table 6, the fourth lens L4 and the eighth lens L8 are aspherical lenses.

[0080]

[0081] Table 5

[0082] Face number K E4 E6 E8 E10 S7 8.58E-04 9.64E-05 1.08E-06 -3.8E-07 S8 2.19E-03 1.12E-04 -3.40E-07 1.17E-07 S16 -2.93E-04 1.21E-05 -3.60E-08 S17 1.603 2.40E-04 5.41E-06 2.58E-07

[0083] Table 6

[0084] Table 7 shows the parameters of the wide-angle lens of the second embodiment related to the above-mentioned conditional expressions (1) to (9).

[0085]

[0086] Table 7

[0087] Table 8 shows the values ​​calculated according to equations (1) to (9) for the wide-angle lens of the second embodiment of the present invention. As can be seen from Table 8, the wide-angle lens of the second embodiment meets the requirements of equations (1) to (9).

[0088]

[0089] Table 8

[0090] In addition, the optical performance of the wide-angle lens of the second embodiment can also meet the requirements. Figure 3B It can be seen that the field curvature is between -0.035mm and 0.005mm. Figure 3CIt can be seen that the distortion is between -4% and 0%, Figure 3D It can be seen that the longitudinal chromatic aberration ranges from -0.015mm to 0.003mm. Clearly, the field curvature, distortion, and longitudinal chromatic aberration of the wide-angle lens of the second embodiment are effectively corrected, resulting in excellent resolution.

[0091] Third embodiment:

[0092] See also Figures 4A to 4D ,in Figure 4A A schematic diagram showing a wide-angle lens according to a third embodiment of the present invention is shown. Figures 4B to 4D The distortion, field curvature and longitudinal chromatic aberration diagrams of the third embodiment are shown in order. The wavelength of light used in the measurement process is 0.555 μm. Figure 4A Unlike the first embodiment, in the wide-angle lens of the third embodiment of the present invention, the third lens element L3 is a meniscus lens, specifically a meniscus lens, the fifth lens element L5 is a biconvex lens, and the seventh lens element L7 is a biconcave lens. Similar to the first embodiment, the first lens group and the second lens group each have three concave lenses and three convex lenses, respectively.

[0093] Table 9 shows the relevant parameters of the wide-angle lens and its various lenses, and Table 10 shows the relevant parameters of the aspheric surfaces in Table 9. As can be seen from Table 10, the eighth lens L8 is an aspheric lens.

[0094]

[0095]

[0096] Table 9

[0097] Face number K E4 E6 E8 S16 -0.426 -5.50E-04 1.34E-05 -4.15E-07 S17 0.454 2.82E-04 5.62E-06 -1.51E-07

[0098] Table 10

[0099] Table 11 shows the parameters of the wide-angle lens of the third embodiment related to the above-mentioned conditional expressions (1) to (9).

[0100]

[0101] Table 11

[0102] Table 12 shows the values ​​calculated according to equations (1) to (9) for the wide-angle lens of the third embodiment of the present invention. As can be seen from Table 12, the wide-angle lens of the third embodiment meets the requirements of equations (1) to (9).

[0103]

[0104] Table 12

[0105] In addition, the optical performance of the wide-angle lens of the third embodiment can also meet the requirements. Figure 4B It can be seen that the field curvature is between -0.03mm and 0.005mm. Figure 4C It can be seen that the distortion is between -3% and 0%, Figure 4D It can be seen that the longitudinal chromatic aberration ranges from -0.018mm to 0.004mm. Clearly, the wide-angle lens of the third embodiment effectively corrects field curvature, distortion, and longitudinal chromatic aberration, resulting in excellent resolution.

[0106] Fourth embodiment:

[0107] See also 5A to 5D ,in Figure 5A A schematic diagram showing a wide-angle lens according to a fourth embodiment of the present invention is shown. Figures 5B to 5D The distortion, field curvature and longitudinal chromatic aberration diagrams of the fourth embodiment are shown in order. The wavelength of light used in the measurement process is 0.555 μm. Figure 5A Unlike the third embodiment, the wide-angle lens of the fourth embodiment of the present invention further includes a ninth lens element, L9, disposed in the first lens group between the first lens element L1 and the second lens element L2. Ninth lens element L9 has negative refractive power, with a convex object-side surface and a concave image-side surface. The refractive power of the wide-angle lens of the fourth embodiment of the present invention, from left to right, is negative, negative, negative, negative, positive, positive, positive, negative, and positive. The first lens group has four concave lenses, and the second lens group has three convex lenses.

[0108] Table 13 shows the relevant parameters of the wide-angle lens and its various lenses, and Table 14 shows the relevant parameters of the aspherical surfaces in Table 13. As can be seen from Table 14, the eighth lens L8 is an aspherical lens.

[0109]

[0110] Table 13

[0111] Face number K E4 E6 E8 S16 0.407 -6.43E-04 1.35E-05 -3.27E-07 S17 4.488 6.75E-04 9.77E-06 1.26E-07

[0112] Table 14

[0113] Table 15 shows the parameters of the wide-angle lens of the fourth embodiment related to the above-mentioned conditional expressions (1) to (9).

[0114]

[0115] Table 15

[0116] Table 16 shows the values ​​calculated according to equations (1) to (9) for the wide-angle lens of the fourth embodiment of the present invention. As can be seen from Table 16, the wide-angle lens of the fourth embodiment meets the requirements of equations (1) to (9).

[0117]

[0118] Table 16

[0119] In addition, the optical performance of the wide-angle lens of the fourth embodiment can also meet the requirements. Figure 5B It can be seen that the field curvature is between -0.16mm and 0.04mm. Figure 5C It can be seen that the distortion is between -22.5% and 0%, Figure 5D It can be seen that the longitudinal chromatic aberration ranges from -0.014mm to 0.002mm. Clearly, the wide-angle lens of the fourth embodiment effectively corrects field curvature, distortion, and longitudinal chromatic aberration, resulting in excellent resolution.

[0120] The conditional formulas that the present invention complies with are (1) 21.02≦f4+f6≦26.89; (2) 18.66≦f4+f8≦23.13; (3) -25.66≦f4+f3≦-5.19; (4) -1.29≦(G7R2-G6R2) / f3≦-0.62; (5) -0.06≦(G7R1 / G3R2) / G5R1≦ 0.12; (6) -5 ≦ (GBR1 + G6R2) / G7R2 ≦ 16; (7) -0.64 ≦ (G7R2 + G6R2) / GAR1 ≦ -0.03; (8) -0.72 ≦ G7R2 / VB ≦ 2.15; (9) -50 ≦ GBR2 + G3R2 ≦ 28 as the center, and the numerical values ​​of the embodiment of the present invention also fall within the range of these conditional expressions. Conditional expressions (1) and (2) help to reduce the angle of the main ray on the imaging plane IMA and increase the amount of peripheral light. Conditional expressions (3), (4), (5), and (7) help to reduce the degree of image curvature and improve the performance of magnification chromatic aberration. Conditional expression (6) can further correct image curvature. Conditional expression (8) helps to correct longitudinal chromatic aberration. If conditional expression (9) is met, the best spherical aberration performance is achieved. Therefore, the wide-angle lens of the present invention has the advantages of small field curvature and good lateral chromatic aberration, and has excellent imaging quality.

[0121] Although the present invention has been disclosed above using preferred embodiments, they are not intended to limit the present invention. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A wide-angle lens, characterized in that: It includes the following components from the object side to the image side on the optical axis: A first lens having a negative refractive power, a convex object-side surface and a concave image-side surface; a second lens having a negative refractive power, a convex object-side surface and a concave image-side surface; a third lens having a negative refractive power and a concave object-side surface; a fourth lens having positive refractive power and a convex image-side surface; a fifth lens having positive refractive power and a convex image-side surface; a sixth lens having positive refractive power, wherein the object-side surface and the image-side surface are convex; a seventh lens having negative refractive power and a concave image-side surface; and an eighth lens element having positive refractive power, wherein the object-side surface and the image-side surface are convex; The wide-angle lens satisfies the following conditions: 21.02≦f4+f6≦26.89, Wherein f4 is the effective focal length of the fourth lens, and f6 is the effective focal length of the sixth lens; The wide-angle lens satisfies at least one of the following conditions: -0.64≦(G7R2+G6R2) / GAR1≦-0.03; -1.29≦(G7R2-G6R2) / f3≦-0.62; Wherein G7R2 is the curvature radius of the image-side surface of the seventh lens element, G6R2 is the curvature radius of the image-side surface of the sixth lens element, GAR1 is the curvature radius of the object-side surface of the first lens element located before the aperture, and f3 is the effective focal length of the third lens element; The wide-angle lens satisfies at least one of the following conditions: -25.66≦f4+f3≦-5.19; -0.06≦(G7R1 / G3R2) / G5R1≦0.12; Wherein G7R1 is the curvature radius of the object-side surface of the seventh lens, G3R2 is the curvature radius of the image-side surface of the third lens, and G5R1 is the curvature radius of the object-side surface of the fifth lens.

2. A wide-angle lens, characterized in that: From the object side to the image side on the optical axis, it includes: A first lens having a negative refractive power, a convex object-side surface and a concave image-side surface; a second lens having a negative refractive power, a convex object-side surface and a concave image-side surface; a third lens having a negative refractive power and a concave object-side surface; a fourth lens having positive refractive power and a convex image-side surface; a fifth lens having positive refractive power and a convex image-side surface; a sixth lens having positive refractive power, wherein the object-side surface and the image-side surface are convex; a seventh lens having negative refractive power and a concave image-side surface; and an eighth lens element having positive refractive power, wherein the object-side surface and the image-side surface are convex; The wide-angle lens satisfies the following conditions: 18.66≦f4+f8≦23.13, Wherein f4 is the effective focal length of the fourth lens, and f8 is the effective focal length of the eighth lens; The wide-angle lens satisfies at least one of the following conditions: -0.64≦(G7R2+G6R2) / GAR1≦-0.03; -1.29≦(G7R2-G6R2) / f3≦-0.62; Wherein G7R2 is the curvature radius of the image-side surface of the seventh lens element, G6R2 is the curvature radius of the image-side surface of the sixth lens element, GAR1 is the curvature radius of the object-side surface of the first lens element located before the aperture, and f3 is the effective focal length of the third lens element; The wide-angle lens satisfies at least one of the following conditions: -25.66≦f4+f3≦-5.19; -0.06≦(G7R1 / G3R2) / G5R1≦0.12; Wherein G7R1 is the curvature radius of the object-side surface of the seventh lens, G3R2 is the curvature radius of the image-side surface of the third lens, and G5R1 is the curvature radius of the object-side surface of the fifth lens.

3. The wide-angle lens according to claim 1 or 2, wherein: The image-side surface of the third lens is concave, and the object-side surface of the seventh lens is convex.

4. The wide-angle lens according to claim 1 or 2, wherein: The image-side surface of the third lens is convex, and the object-side surface of the fifth lens is concave.

5. The wide-angle lens according to claim 1 or 2, wherein: The image-side surface of the third lens is convex, and the object-side surface of the seventh lens is concave.

6. The wide-angle lens according to claim 1 or 2, wherein: The object-side surface of the fifth lens is convex.

7. The wide-angle lens according to claim 1 or 2, wherein: It also includes an aperture, which is arranged between two adjacent lenses among the first lens to the eighth lens, wherein the lens arranged along the aperture toward the object side is a lens located in front of the aperture, and the lens arranged along the aperture toward the image side is a lens located behind the aperture, wherein the lens located in front of the aperture includes at least one lens, and the lens located behind the aperture includes at least one lens.

8. The wide-angle lens according to claim 7, wherein: The wide-angle lens satisfies at least one of the following conditions: -5≦(GBR1+G6R2) / G7R2≦16; -50≦GBR2+G3R2≦28; -0.72≦G7R2 / VB≦2.15; Wherein GBR1 is the curvature radius of the object-side surface of the first lens located after the aperture, GBR2 is the curvature radius of the image-side surface of the first lens located after the aperture, G3R2 is the curvature radius of the image-side surface of the third lens, G6R2 is the curvature radius of the image-side surface of the sixth lens, G7R2 is the curvature radius of the image-side surface of the seventh lens, and VB is the Abbe coefficient of the first lens located after the aperture.

9. The wide-angle lens according to claim 1 or 2, wherein: The optical system further comprises a ninth lens disposed between the first lens and the third lens. The ninth lens has negative refractive power, an object-side surface thereof is convex, and an image-side surface thereof is concave.

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