Imaging lens system

Abstract

The application discloses an imaging lens system, which comprises eight lenses, and the eight lenses are sequentially arranged from the object side to the image side as 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. The eight lenses respectively have an object side surface facing the object side direction and an image side surface facing the image side direction. The eighth lens has a negative refractive power. At least one surface of at least one lens in the imaging lens system has at least one inflection point. The total number of the lenses in the imaging lens system is eight. When certain conditions are met, the imaging lens system can meet the requirements of a large aperture and miniaturization.

Description

[0001] This divisional application is a further divisional application filed based on the divisional application with the application number 202111324212.1, the filing date of November 10, 2021, and the invention title of "Imaging Lens System". The filing date of the original application is: November 1, 2018; the application number is: 201811292488.4; the invention title is: Imaging Lens System, Image Capturing Device, and Electronic Device. Technical Field

[0002] The present invention relates to an imaging lens system, particularly an imaging lens system suitable for an electronic device. Background Art

[0003] With the continuous improvement of semiconductor process technology, the performance of electronic photosensitive elements has been enhanced, and pixels can reach a smaller size. Therefore, an optical lens with high imaging quality has become an essential part.

[0004] With the rapid development of technology, the application range of electronic devices equipped with optical lenses is more extensive, and the requirements for optical lenses are also more diverse. Since it is relatively difficult for conventional optical lenses to balance the requirements of imaging quality, sensitivity, aperture size, volume, or viewing angle, the present invention provides an optical lens to meet the requirements. Summary of the Invention

[0005] The present invention provides an imaging lens system. Among them, the imaging lens system includes eight lenses. When specific conditions are met, the imaging lens system provided by the present invention can simultaneously meet the requirements of a large aperture and miniaturization.

[0006] The present invention provides an imaging lens system, including eight lenses. The eight lenses are, in order from the object side to the image side, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens. The eight lenses respectively have an object side surface facing the object side direction and an image side surface facing the image side direction. The eighth lens has a negative refractive power. At least one surface of at least one lens in the imaging lens system has at least one inflection point. The total number of lenses in the imaging lens system is eight. The minimum Abbe number of the lenses in the imaging lens system is Vmin, the distance from the object side surface of the first lens to the imaging plane on the optical axis is TL, the focal length of the imaging lens system is f, the distance from the image side surface of the eighth lens to the imaging plane on the optical axis is BL, and the distance from the object side surface of the first lens to the image side surface of the eighth lens on the optical axis is TD, which satisfy the following conditions:

[0007] 8.0 < Vmin < 20.0;

[0008] 0.50 < TL / f < 1.10; and

[0009] 0 <BL / TD<0.30。

[0010] When Vmin meets the above conditions, the optical path can be adjusted and the converging ability between different wavelengths of light can be balanced to correct chromatic aberration.

[0011] When TL / f meets the above conditions, the overall length can be balanced and the field of view size can be controlled, so that the imaging lens system can meet the product application requirements.

[0012] When BL / TD meets the above conditions, it helps to shorten the back focal length in order to control the overall length of the imaging lens system.

[0013] The foregoing description of the invention and the following description of the embodiments are intended to demonstrate and explain the spirit and principles of the invention, and to provide a further explanation of the scope of protection of the patent application claims. Attached Figure Description

[0014] Figure 1 A schematic diagram of an image-capturing device according to a first embodiment of the present invention is shown.

[0015] Figure 2 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the first embodiment.

[0016] Figure 3 A schematic diagram of an image-capturing device according to a second embodiment of the present invention is shown.

[0017] Figure 4 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the second embodiment.

[0018] Figure 5 A schematic diagram of an image-capturing device according to a third embodiment of the present invention is shown.

[0019] Figure 6 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the third embodiment.

[0020] Figure 7 A schematic diagram of an image-capturing device according to a fourth embodiment of the present invention is shown.

[0021] Figure 8 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the fourth embodiment.

[0022] Figure 9 A schematic diagram of an image-capturing device according to a fifth embodiment of the present invention is shown.

[0023] Figure 10 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the fifth embodiment.

[0024] Figure 11A schematic diagram of an image-capturing device according to a sixth embodiment of the present invention is shown.

[0025] Figure 12 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the sixth embodiment.

[0026] Figure 13 A schematic diagram of an image-capturing device according to a seventh embodiment of the present invention is shown.

[0027] Figure 14 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the seventh embodiment.

[0028] Figure 15 A schematic diagram of an imaging device according to the eighth embodiment of the present invention is shown.

[0029] Figure 16 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the eighth embodiment.

[0030] Figure 17 A schematic diagram of an image-capturing device according to a ninth embodiment of the present invention is shown.

[0031] Figure 18 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the ninth embodiment.

[0032] Figure 19 A schematic diagram of an image-capturing device according to the tenth embodiment of the present invention is shown.

[0033] Figure 20 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the tenth embodiment.

[0034] Figure 21 A schematic diagram of an image-capturing device according to the eleventh embodiment of the present invention is shown.

[0035] Figure 22 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the eleventh embodiment.

[0036] Figure 23 A schematic diagram of an image-capturing device according to the twelfth embodiment of the present invention is shown.

[0037] Figure 24 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the twelfth embodiment.

[0038] Figure 25 A schematic diagram of an image-capturing device according to a thirteenth embodiment of the present invention is shown.

[0039] Figure 26 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the thirteenth embodiment.

[0040] Figure 27 A perspective view of an imaging device according to the fourteenth embodiment of the present invention is shown.

[0041] Figure 28 A perspective view of one side of an electronic device according to the fifteenth embodiment of the present invention is shown.

[0042] Figure 29 Draw Figure 28 A three-dimensional view of the other side of the electronic device.

[0043] Figure 30 Draw Figure 28 System block diagram of an electronic device.

[0044] Figure 31 A schematic diagram illustrating parameters Y11, Y51, Yc72 and Y82, as well as the critical point and inflection point of the image-side surface of the seventh lens, according to the first embodiment of the present invention.

[0045] In the attached figures, the following labels are used:

[0046] Image capturing devices: 10, 10a, 10b, 10c

[0047] Imaging lens: 11

[0048] Drive unit: 12

[0049] Electronic photosensitive element: 13

[0050] Image stabilization module: 14

[0051] Electronic devices: 20

[0052] Flash module: 21

[0053] Focusing assist module: 22

[0054] Image signal processor: 23

[0055] User Interface: 24

[0056] Image software processor: 25

[0057] Subject: 26

[0058] Inflection point: P

[0059] Critical point: C

[0060] Aperture: 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300

[0061] Apertures: 901, 1001, 1101, 1201, 1301

[0062] First lens: 110, 210, 310, 410, 510, 610, 710, 810, 910, 1010, 1110, 1210, 1310

[0063] Object-side surfaces: 111, 211, 311, 411, 511, 611, 711, 811, 911, 1011, 1111, 1211, 1311

[0064] Image side surface: 112, 212, 312, 412, 512, 612, 712, 812, 912, 1012, 1112, 1212, 1312

[0065] Second lens: 120, 220, 320, 420, 520, 620, 720, 820, 920, 1020, 1120, 1220, 1320

[0066] Object-side surfaces: 121, 221, 321, 421, 521, 621, 721, 821, 921, 1021, 1121, 1221, 1321

[0067] Image side surface: 122, 222, 322, 422, 522, 622, 722, 822, 922, 1022, 1122, 1222, 1322

[0068] Third lens: 130, 230, 330, 430, 530, 630, 730, 830, 930, 1030, 1130, 1230, 1330

[0069] Object side surface: 131, 231, 331, 431, 531, 631, 731, 831, 931, 1031, 1131, 1231, 1331

[0070] Image side surface: 132, 232, 332, 432, 532, 632, 732, 832, 932, 1032, 1132, 1232, 1332

[0071] Fourth lens: 140, 240, 340, 440, 540, 640, 740, 840, 940, 1040, 1140, 1240, 1340

[0072] Object-side surfaces: 141, 241, 341, 441, 541, 641, 741, 841, 941, 1041, 1141, 1241, 1341

[0073] Side surface: 142, 242, 342, 442, 542, 642, 742, 842, 942, 1042, 1142, 1242, 1342

[0074] Fifth lens: 150, 250, 350, 450, 550, 650, 750, 850, 950, 1050, 1150, 1250, 1350

[0075] Object-side surfaces: 151, 251, 351, 451, 551, 651, 751, 851, 951, 1051, 1151, 1251, 1351

[0076] Image side surface: 152, 252, 352, 452, 552, 652, 752, 852, 952, 1052, 1152, 1252, 1352

[0077] Sixth lens: 160, 260, 360, 460, 560, 660, 760, 860, 960, 1060, 1160, 1260, 1360

[0078] Object-side surface: 161, 261, 361, 461, 561, 661, 761, 861, 961, 1061, 1161, 1261, 1361

[0079] Image side surface: 162, 262, 362, 462, 562, 662, 762, 862, 962, 1062, 1162, 1262, 1362

[0080] Seventh lens: 170, 270, 370, 470, 570, 670, 770, 870, 970, 1070, 1170, 1270, 1370

[0081] Object side surface: 171, 271, 371, 471, 571, 671, 771, 871, 971, 1071, 1171, 1271, 1371

[0082] Image side surface: 172, 272, 372, 472, 572, 672, 772, 872, 972, 1072, 1172, 1272, 1372

[0083] Eighth lens: 180, 280, 380, 480, 580, 680, 780, 880, 980, 1080, 1180, 1280, 1380

[0084] Object-side surface: 181, 281, 381, 481, 581, 681, 781, 881, 981, 1081, 1181, 1281, 1381

[0085] Image side surface: 182, 282, 382, ​​482, 582, 682, 782, 882, 982, 1082, 1182, 1282, 1382

[0086] Filter elements: 190, 290, 390, 490, 590, 690, 790, 890, 990, 1090, 1190, 1290, 1390

[0087] Imaging planes: 195, 295, 395, 495, 595, 695, 795, 895, 995, 1095, 1195, 1295, 1395

[0088] Electronic photosensitive elements: 199, 299, 399, 499, 599, 699, 799, 899, 999, 1099, 1199, 1299, 1399

[0089] Y11: Maximum effective radius of the object-side surface of the first lens

[0090] Y51: Maximum effective radius of the object-side surface of the fifth lens

[0091] Y82: Maximum effective radius of the image-side surface of the eighth lens

[0092] Yc72: The perpendicular distance between the critical point of the image-side surface of the seventh lens and the optical axis. Detailed Implementation

[0093] The following detailed description of the features and advantages of the present invention in the embodiments is sufficient to enable any person skilled in the art to understand the technical content of the present invention and implement it accordingly. Based on the disclosure in this specification, the scope of protection of the claims, and the accompanying drawings, any person skilled in the art can easily understand the related objects and advantages of the present invention. The following embodiments further illustrate the points of the present invention in detail, but are not intended to limit the scope of the present invention in any way.

[0094] The imaging lens system includes eight lenses, which are arranged in the following order from the object side to the image side: first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens.

[0095] The first lens may have a positive refractive power; thereby, the main light converging ability of the imaging lens system can be provided to effectively compress the spatial configuration between the lenses, thereby meeting the requirement of miniaturization. The object-side surface of the first lens may be convex near the optical axis; thereby, it is beneficial to receive off-axis field light to slow down the angle between the light and the lens surface, thereby avoiding total reflection on the lens surface.

[0096] The second lens may have a negative refractive power; thereby, the aberration generated by the first lens can be balanced, and thus spherical aberration and chromatic aberration can be corrected. The image-side surface of the second lens may be concave near the optical axis; thereby, the aberration generated by the first lens can be effectively balanced to improve the image quality.

[0097] The image-side surface of the third lens may be concave near the optical axis. Thereby, it is beneficial to form a miniaturized telescopic structure and can avoid generating excessive aberration.

[0098] The image-side surface of the seventh lens may be concave near the optical axis. Thereby, it helps to shorten the back focal length of the imaging lens system to meet the requirement of miniaturization.

[0099] In the imaging lens system disclosed by the present invention, at least one surface of at least one lens has at least one inflection point; thereby, it is beneficial to correct off-axis aberration and can reduce the volume of the imaging lens system. Preferably, at least three lenses in the imaging lens system each have at least one surface with at least one inflection point; thereby, it is beneficial to correct coma and astigmatism, meet the characteristics of miniaturization, and make the Petzval surface of the imaging lens system flatter. Please refer to Figure 31 , this figure is a schematic diagram of the imaging lens system having an inflection point P on the image-side surface 172 of the seventh lens according to the first embodiment of the present invention. Figure 31 The inflection point of the image-side surface of the seventh lens is shown as an exemplary illustration, and the object-side surface or image-side surface of the remaining lenses may also have an inflection point.

[0100] The minimum Abbe number of the lenses in the imaging lens system is Vmin, which can satisfy the following condition: 8.0 < Vmin < 22.5. Thereby, the optical path can be adjusted and the converging ability between light rays of different bands can be balanced to correct chromatic aberration. Preferably, it can satisfy the following condition: 8.0 < Vmin < 20.0. More preferably, it can satisfy the following condition: 10.0 < Vmin < 20.0. Even more preferably, it can further satisfy the following condition: 15.0 < Vmin < 19.0.

[0101] Half of the maximum viewing angle in the imaging lens system is HFOV, which can satisfy the following conditions: 5.0 [degrees] < HFOV < 30.0 [degrees]. Thereby, the viewing angle size can be effectively controlled, enabling the imaging lens system to have a better imaging range for more diverse applications. Preferably, it can further satisfy the following conditions: 5.0 [degrees] < HFOV < 25.0 [degrees].

[0102] The focal length of the imaging lens system is f, and the entrance pupil diameter of the imaging lens system is EPD, which can satisfy the following conditions: 0.80 < f / EPD < 2.20. Thereby, the light entrance aperture of the imaging lens system can be effectively adjusted to control the incident light amount, thereby enhancing the image brightness. Preferably, it can further satisfy the following conditions: 1.0 < f / EPD < 2.0. In one embodiment, it can satisfy the following conditions: 0.80 < f / EPD < 1.80.

[0103] The distance from the image-side surface of the eighth lens to the imaging surface on the optical axis is BL, and the distance from the object-side surface of the first lens to the image-side surface of the eighth lens on the optical axis is TD, which can satisfy the following conditions: 0 < BL / TD < 0.30. Thereby, it helps to shorten the back focal length to control the total length of the imaging lens system. Preferably, it can satisfy the following conditions: 0 < BL / TD < 0.25. More preferably, it can further satisfy the following conditions: 0 < BL / TD < 0.18.

[0104] The focal length of the imaging lens system is f, and the focal length of the first lens is f1, which can satisfy the following conditions: 0.32 < f / f1 < 3.80. Thereby, it can ensure that the first lens provides sufficient ability to converge light at the object-side end of the imaging lens system to meet the telescopic function.

[0105] The Abbe number of the eighth lens is V8, which can satisfy the following conditions: 8.0 < V8 < 24.5. Thereby, it can provide better chromatic aberration balance ability for the eighth lens to avoid the imaging position shift of light in different bands, thereby enhancing the imaging quality. Preferably, it can satisfy the following conditions: 8.0 < V8 < 22.0. More preferably, it can further satisfy the following conditions: 8.0 < V8 < 20.0.

[0106] The distance from the object-side surface of the first lens to the imaging surface on the optical axis is TL, and the focal length of the imaging lens system is f, which can satisfy the following conditions: 0.50 < TL / f < 1.30. Thereby, it can balance the total length and control the viewing angle size to enable the imaging lens system to meet the product application requirements. Preferably, it can further satisfy the following conditions: 0.50 < TL / f < 1.10.

[0107] In the imaging lens system disclosed by the present invention, at least four lenses can be made of plastic material. Thereby, the production cost of the imaging lens system can be effectively reduced, and the design freedom can be enhanced to facilitate the optimization of the off-axis aberration correction ability.

[0108] The distance from the object side surface of the first lens to the imaging surface on the optical axis is TL, and the entrance pupil diameter of the imaging lens system is EPD, which can satisfy the following condition: 0.90 < TL / EPD < 1.90. Thereby, the requirements of short overall length and large aperture can be satisfied simultaneously, enabling the imaging lens system to capture sufficiently bright images within a limited lens space. Preferably, it can further satisfy the following condition: 1.10 < TL / EPD < 1.67.

[0109] In the imaging lens system disclosed in the present invention, the Abbe numbers of at least four lenses are all less than 35.0. Thereby, it helps to ensure that the lens materials in the imaging lens system have sufficient ability to control light, balance the focusing positions of light in different bands, and thus avoid the occurrence of image overlap. Preferably, the Abbe numbers of at least four lenses are all less than 30.0. More preferably, the Abbe numbers of at least four lenses are all less than 25.0. In the present invention, the Abbe number V of a single lens can be calculated by the following formula: V = (Nd - 1) / (NF - NC), where Nd is the refractive index of the single lens measured at the helium d-line wavelength (587.6 nm), NF is the refractive index of the single lens measured at the hydrogen F-line wavelength (486.1 nm), and NC is the refractive index of the single lens measured at the hydrogen C-line wavelength (656.3 nm).

[0110] The focal length of the fifth lens is f5, and the focal length of the eighth lens is f8, which can satisfy the following condition: -0.50 < f8 / f5 < 9.0. Thereby, it can ensure that the refractive power intensity of the eighth lens has sufficient optical path control ability and effectively alleviate the refractive power intensity at the intersection of each field in the middle section of the imaging lens system to avoid generating excessive aberrations. Preferably, it can further satisfy the following condition: -0.40 < f8 / f5 < 3.0.

[0111] The sum of the lens thicknesses of each lens on the optical axis in the imaging lens system is ΣCT, and the sum of the spacing distances between each two adjacent lenses on the optical axis in the imaging lens system is ΣAT, which can satisfy the following condition: 1.10 < ΣCT / ΣAT < 3.50. Thereby, it can balance the lens thickness and the lens gap, facilitating lens assembly and improving the qualification rate. Preferably, it can further satisfy the following condition: 1.20 < ΣCT / ΣAT < ۲.۵۰.

[0112] The radius of curvature of the object side surface of the first lens is R1, and the thickness of the first lens on the optical axis is CT1, which can satisfy the following condition: 0.50 < R1 / CT1 < 2.65. Thereby, it can strengthen the optical path control ability of the first lens and improve the lens structure strength to enhance the adaptability of the lens to the external environment. Preferably, it can further satisfy the following condition: 0.80 < R1 / CT1 < 2.50.

[0113] The radius of curvature of the object-side surface of the seventh lens is R13, and the radius of curvature of the image-side surface of the seventh lens is R14, which can satisfy the following condition: (R13 - R14) / (R13 + R14) < 5.0. Thereby, the surface shape of the seventh lens can be balanced to enhance the ability of aberration correction, and further improve the image quality. Preferably, it can satisfy the following condition: -2.0 < (R13 - R14) / (R13 + R14) < 3.0. More preferably, it can further satisfy the following condition: -1.0 < (R13 - R14) / (R13 + R14) < 2.0.

[0114] The maximum effective radius of the object-side surface of the first lens is Y11, the maximum effective radius of the image-side surface of the eighth lens is Y82, the maximum imaging height of the imaging lens system is ImgH (i.e., half of the total diagonal length of the effective sensing area of the electronic photosensitive element), and the focal length of the imaging lens system is f, which can satisfy the following condition: 0 < (|Y11 - Y82| + |Y82 - ImgH|) / f < 0.15. Thereby, the gap among the object-side end, image-side end and imaging height of the imaging lens system can be balanced, and the lens size can be controlled to ensure the lens molding quality, and further maintain the molding stability. Please refer to Figure 31 , this figure is a schematic diagram with parameters Y11 and Y82 in accordance with the first embodiment of the present invention.

[0115] The maximum refractive index of the lenses in the imaging lens system is Nmax, which can satisfy the following condition: 1.60 < Nmax < 1.72. Thereby, the lens material can be controlled to avoid excessive manufacturing difficulty of the lens, and further increase the possibility of commercialization of the lens. Preferably, it can further satisfy the following condition: 1.65 < Nmax < 1.70.

[0116] The focal length of the imaging lens system is f, the radius of curvature of the object-side surface of a lens in the imaging lens system is Ro, the radius of curvature of the image-side surface of the lens is Ri, and there can be at least one lens in the imaging lens system that satisfies the following condition: |f / Ro| + |f / Ri| < 0.50. Thereby, it is ensured that there is at least one aberration correction lens (CorrectionLens) in the imaging lens system, and the surface curvature of the lens is avoided from being too large, so that it has the function of balancing the aberrations generated by the object-side end and image-side end lenses. Preferably, there can be at least one lens in the imaging lens system that satisfies the following condition: |f / Ro| + |f / Ri| < 0.30.

[0117] The entrance pupil diameter of the imaging lens system is EPD, and the distance from the image side surface of the eighth lens to the imaging surface on the optical axis is BL, which can satisfy the following condition: 4.50 < EPD / BL < 18.0. Thereby, the imaging lens system retains an appropriate back focal length in a limited space for assembly, while ensuring that the imaging lens system has sufficient light entrance amount to meet the specification requirements of the product device. Preferably, it can further satisfy the following condition: 4.50 < EPD / BL < 9.0.

[0118] The distance from the image side surface of the eighth lens to the imaging surface on the optical axis is BL, and the thickness of the first lens on the optical axis is CT1, which can satisfy the following condition: 0 < BL / CT1 < 0.95. Thereby, the thickness of the first lens can be increased, so that the lens has sufficient strength to resist various environmental factors, to maintain the stability of the lens quality, and at the same time control the back focal length to achieve the purpose of miniaturization. Preferably, it can further satisfy the following condition: 0.10 < BL / CT1 < 0.70.

[0119] The maximum effective radius of the object side surface of the first lens is Y11, the maximum imaging height of the imaging lens system is ImgH, and the entrance pupil diameter of the imaging lens system is EPD, which can satisfy the following condition: -0.27 < (Y11 - ImgH) / EPD < 0. Thereby, the size difference between the object side end and the image side end can be balanced, and at the same time, it is ensured that the imaging lens system has sufficient light entrance amount.

[0120] The focal length of the imaging lens system is f, and the focal length of the fifth lens is f5, which can satisfy the following condition: -0.25 < f / f5 < 1.50. Thereby, the refractive power intensity of the fifth lens can be balanced, and the sensitivity can be reduced. Preferably, it can further satisfy the following condition: 0 < f / f5 < 1.0.

[0121] The imaging lens system disclosed in the present invention further includes an aperture. The distance from the aperture to the imaging surface on the optical axis is SL, and the distance from the object side surface of the first lens to the imaging surface on the optical axis is TL, which can satisfy the following condition: 0.50 < SL / TL < 0.95. Thereby, the aperture position can be effectively balanced to facilitate controlling the lens volume. Preferably, it can further satisfy the following condition: 0.50 < SL / TL < 0.85.

[0122] The focal length of the imaging lens system is f, half of the maximum viewing angle in the imaging lens system is HFOV, and the entrance pupil diameter of the imaging lens system is EPD, which can satisfy the following condition: 0.20 < f×tan(HFOV) / EPD < 1.0. Thereby, it is beneficial to form an optical system with a telephoto function and at the same time has sufficient light entrance amount to avoid insufficient image brightness. Preferably, it can further satisfy the following condition: 0.30 < f×tan(HFOV) / EPD < 0.73.

[0123] The maximum effective radius of the object-side surface of the first lens is Y11, the maximum effective radius of the image-side surface of the eighth lens is Y82, the distance from the image-side surface of the eighth lens to the imaging surface on the optical axis is BL, and the focal length of the imaging lens system is f. The following conditions can be satisfied: 0 < (|Y11 - Y82| + BL) / f < 0.20. Thereby, it is possible to avoid excessive difference in the apertures at both ends of the lens barrel, which may affect the light incident amount, and at the same time, shorten the back focal length to achieve an appropriate spatial configuration.

[0124] The Abbe number of the first lens is V1, the Abbe number of the second lens is V2, the Abbe number of the third lens is V3, the Abbe number of the fourth lens is V4, the Abbe number of the fifth lens is V5, the Abbe number of the sixth lens is V6, the Abbe number of the seventh lens is V7, the Abbe number of the eighth lens is V8, and the Abbe number of the i-th lens is Vi. The following conditions can be satisfied: 150.0 < ΣVi < 320.0, where i = 1, 2, 3, 4, 5, 6, 7, 8. Thereby, it is possible to increase the density difference between the lens material and air, so that the imaging lens system in a limited space can have a strong optical path control ability. Preferably, the following conditions can be further satisfied: 150.0 < ΣVi < 300.0, where i = 1, 2, 3, 4, 5, 6, 7, 8.

[0125] The focal length of the imaging lens system is f, the focal length of the fifth lens is f5, and the focal length of the sixth lens is f6. The following conditions can be satisfied: -0.50 < f / f5 + f / f6 < 1.0. Thereby, the fifth lens and the sixth lens are balanced with each other, and the aberrations are corrected in a complementary form to optimize the imaging quality. Preferably, the following conditions can be further satisfied: -0.20 < f / f5 + f / f6 < 0.50.

[0126] The perpendicular distance from the critical point of the image-side surface of the seventh lens to the optical axis is Yc72, and the focal length of the imaging lens system is f. The following conditions can be satisfied: 0.02 < Yc72 / f < 0.70. Thereby, it is possible to strengthen the correction ability of the off-axis aberration at the image-side end of the imaging lens system, and it is beneficial to reduce distortion and image curvature. Preferably, the following conditions can be further satisfied: 0.02 < Yc72 / f < 0.28. Please refer to Figure 31 , this figure is a schematic diagram of the critical point C of the image-side surface 172 of the seventh lens in accordance with the first embodiment of the present invention.

[0127] The focal length of the fifth lens is f5, and the focal length of the seventh lens is f7. The following conditions can be satisfied: f5 / f7 < 0.50. Thereby, it is possible to balance the refractive power configuration of the fifth lens and the seventh lens to optimize the aberration correction ability and further improve the imaging quality. Preferably, the following conditions can be further satisfied: -5.0 < f5 / f7 < 0.35.

[0128] The radius of curvature of the image-side surface of the fourth lens is R8, and the focal length of the imaging lens system is f, which can satisfy the following condition: -1.50 < R8 / f < 1.50. Thereby, it can be ensured that the image-side surface of the fourth lens has sufficient refractive power to effectively control the light path direction. Preferably, it can further satisfy the following condition: 0 < R8 / f < 1.50.

[0129] The focal length of the imaging lens system is f, and the maximum imaging height of the imaging lens system is ImgH, which can satisfy the following condition: 2.10 < f / ImgH < 3.80. Thereby, it is beneficial to control the field angle of the imaging lens system for application in various different fields.

[0130] The radius of curvature of the object-side surface of the sixth lens is R11, and the radius of curvature of the image-side surface of the sixth lens is R12, which can satisfy the following condition: -0.50 < (R11 + R12) / (R11 - R12) < 15.0. Thereby, it can balance the light path directions in the tangential direction and the sagittal direction to facilitate the correction of astigmatism. Preferably, it can further satisfy the following condition: -0.20 < (R11 + R12) / (R11 - R12) < 3.0.

[0131] The maximum effective radius of the object-side surface of the first lens is Y11, the maximum effective radius of the object-side surface of the fifth lens is Y51, and the maximum effective radius of the image-side surface of the eighth lens is Y82, which can satisfy the following condition: 0.70 < (Y82 - Y51) / (Y11 - Y51) < 2.50. Thereby, it can effectively control the outer diameter ratio of the front, middle, and rear segments of the imaging lens system to improve symmetry, improve image quality, and reduce sensitivity. Please refer to Figure 31 , this figure is a schematic diagram with parameters Y11, Y51, and Y82 in accordance with the first embodiment of the present invention.

[0132] The entrance pupil diameter of the imaging lens system is EPD, and the maximum imaging height of the imaging lens system is ImgH, which can satisfy the following condition: 1.20 < EPD / ImgH < 2.80. Thereby, it helps to ensure that the imaging surface can receive sufficient light to meet the requirements of image brightness.

[0133] The Abbe number of the first lens is V1, the Abbe number of the second lens is V2, the Abbe number of the third lens is V3, the Abbe number of the fourth lens is V4, the Abbe number of the fifth lens is V5, the Abbe number of the sixth lens is V6, the Abbe number of the seventh lens is V7, the Abbe number of the eighth lens is V8, the Abbe number of the i-th lens is Vi, the refractive index of the first lens is N1, the refractive index of the second lens is N2, the refractive index of the third lens is N3, the refractive index of the fourth lens is N4, the refractive index of the fifth lens is N5, the refractive index of the sixth lens is N6, the refractive index of the seventh lens is N7, the refractive index of the eighth lens is N8, the refractive index of the i-th lens is Ni, and the minimum value of Vi / Ni is (Vi / Ni)min, which satisfies the following conditions: 9.0 < (Vi / Ni)min < 11.80, where i = 1, 2, 3, 4, 5, 6, 7, 8. Thereby, the imaging lens system can have sufficient image control ability to correct various aberrations. Preferably, it can further satisfy the following conditions: 9.5 < (Vi / Ni)min < 11.5.

[0134] The distance from the object side surface of the first lens to the imaging surface on the optical axis is TL, which satisfies the following conditions: 4.0 [mm] < TL < 8.0 [mm]. Thereby, it is beneficial to control the total length of the imaging lens system to expand the product application range and meet the requirements of the current market. Preferably, it can further satisfy the following conditions: 4.5 [mm] < TL < 7.0 [mm].

[0135] The maximum imaging height of the imaging lens system is ImgH, which satisfies the following conditions: 1.50 [mm] < ImgH < 4.50 [mm]. Thereby, the light-receiving area can be controlled to ensure the image brightness and achieve a balance with the specification requirements. Preferably, it can further satisfy the following conditions: 1.80 [mm] < ImgH < 3.20 [mm].

[0136] The above technical features in the imaging lens system of the present invention can be combined and configured to achieve the corresponding effects.

[0137] In the imaging lens system disclosed in the present invention, the material of the lens can be glass or plastic. If the material of the lens is glass, the freedom of refractive power configuration of the imaging lens system can be increased, and the glass lens can be made by techniques such as grinding or molding. If the lens material is plastic, the production cost can be effectively reduced. In addition, an aspherical surface (ASP) can be provided on the lens surface, thereby obtaining more control variables to reduce aberrations, reduce the number of lenses, and effectively reduce the total length of the imaging lens system of the present invention, and the aspherical surface can be made by methods such as plastic injection molding or molding of glass lenses.

[0138] In the imaging lens system disclosed in this invention, additives can be selectively added to any (or more) lens materials to alter the lens's transmittance for specific wavelengths of light, thereby reducing stray light and color shift. For example, the additives may filter out light in the 600 nm to 800 nm wavelength range to help reduce excess red or infrared light; or they may filter out light in the 350 nm to 450 nm wavelength range to reduce excess blue or ultraviolet light. Therefore, the additives can prevent specific wavelengths of light from interfering with imaging. Furthermore, the additives can be uniformly mixed into plastic and manufactured into lenses using injection molding technology.

[0139] In the imaging lens system disclosed in this invention, if the lens surface is aspherical, it means that all or part of the optically effective area of ​​the lens surface is aspherical.

[0140] In the imaging lens system disclosed in this invention, if the lens surface is convex and the position of the convex surface is not defined, it means that the convex surface can be located near the optical axis of the lens surface; if the lens surface is concave and the position of the concave surface is not defined, it means that the concave surface can be located near the optical axis of the lens surface. If the refractive power or focal length of the lens is not defined in its region, it means that the refractive power or focal length of the lens can be the refractive power or focal length of the lens near the optical axis.

[0141] In the imaging lens system disclosed in this invention, the inflection point of the lens surface refers to the boundary point where the curvature of the lens surface changes from positive to negative. The critical point of the lens surface refers to the point of tangency on the tangent line between a plane perpendicular to the optical axis and the lens surface, and the critical point is not located on the optical axis.

[0142] In the imaging lens system disclosed in this invention, the imaging surface of the imaging lens system can be a plane or a curved surface with any curvature, depending on the corresponding electronic photosensitive element, especially a curved surface with a concave surface facing the object side.

[0143] In the imaging lens system disclosed in this invention, one or more imaging correction elements (such as planar elements) can be selectively disposed between the lens closest to the imaging surface and the imaging surface to achieve the effect of correcting image curvature (e.g., image warping). The optical properties of this imaging correction element, such as curvature, thickness, refractive index, position, and surface type (convex or concave, spherical or aspherical, diffractive surface, and Fresnel surface, etc.), can be adjusted according to the requirements of the imaging device. Generally, a preferred configuration of the imaging correction element is to place a thin plano-concave element with a concave surface in the object-side direction near the imaging surface.

[0144] In the imaging lens system disclosed in this invention, at least one aperture stop may be provided, which may be located before the first lens, between the lenses, or after the last lens. The aperture stop may be of the type such as a glare stop or a field stop, which can be used to reduce stray light and help improve image quality.

[0145] In the imaging lens system disclosed in this invention, the aperture can be configured as a front aperture or a central aperture. A front aperture means the aperture is positioned between the subject and the first lens, while a central aperture means the aperture is positioned between the first lens and the imaging plane. A front aperture allows for a longer distance between the exit pupil and the imaging plane, resulting in a telecentric effect and increasing the efficiency of image reception by the CCD or CMOS sensor. A central aperture helps to expand the field of view of the imaging lens system.

[0146] This invention may appropriately incorporate a variable aperture element, which can be a mechanical component or a light-regulating element, and whose aperture size and shape can be controlled electrically or by electrical signals. The mechanical component may include movable parts such as blade assemblies or shielding plates; the light-regulating element may include light-filtering elements, electrochromic materials, liquid crystal layers, or other masking materials. This variable aperture element can enhance image adjustment capabilities by controlling the amount of light entering the image or the exposure time. Furthermore, this variable aperture element can also be the aperture of this invention, allowing image quality, such as depth of field or exposure speed, to be adjusted by changing the aperture value.

[0147] Based on the above implementation methods, specific embodiments are presented below and described in detail with reference to the accompanying drawings.

[0148] <First Embodiment>

[0149] Please refer to Figures 1 to 2 ,in Figure 1 A schematic diagram of an image-capturing device according to a first embodiment of the present invention is shown. Figure 2 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the first embodiment. Figure 1 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 199. The imaging lens system, from the object side to the image side, sequentially includes a first lens 110, a second lens 120, an aperture 100, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, an eighth lens 180, a filter element 190, and an imaging surface 195. The electronic photosensitive element 199 is disposed on the imaging surface 195. The imaging lens system includes eight lenses (110, 120, 130, 140, 150, 160, 170, 180), and there are no other interposed lenses between the lenses.

[0150] The first lens 110 has positive refractive power and is made of plastic. Its object-side surface 111 is convex near the optical axis, and its image-side surface 112 is concave near the optical axis. Both of its surfaces are aspherical.

[0151] The second lens 120 has positive refractive power and is made of plastic. Its object-side surface 121 is convex near the optical axis, and its image-side surface 122 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 121 has one inflection point, and its image-side surface 122 has two inflection points.

[0152] The third lens 130 has negative refractive power and is made of plastic. Its object-side surface 131 is convex near the optical axis, and its image-side surface 132 is concave near the optical axis. Both of its surfaces are aspherical.

[0153] The fourth lens 140 has negative refractive power and is made of plastic. Its object-side surface 141 is convex near the optical axis, and its image-side surface 142 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 141 has a point of inflection, and its image-side surface 142 has a point of inflection.

[0154] The fifth lens 150 has positive refractive power and is made of plastic. Its object-side surface 151 is convex near the optical axis, and its image-side surface 152 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 151 has one inflection point, and its image-side surface 152 has two inflection points.

[0155] The sixth lens 160 has positive refractive power and is made of plastic. Its object-side surface 161 is concave near the optical axis, and its image-side surface 162 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 161 has two inflection points, and its image-side surface 162 has two inflection points.

[0156] The seventh lens 170 has negative refractive power and is made of plastic. Its object-side surface 171 is convex near the optical axis, and its image-side surface 172 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 171 has three inflection points, its image-side surface 172 has two inflection points, and its image-side surface 172 has at least one critical point off-axis.

[0157] The eighth lens 180 has negative refractive power and is made of plastic. Its object-side surface 181 is concave near the optical axis, and its image-side surface 182 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 181 has three inflection points, and its image-side surface 182 has one inflection point.

[0158] The filter element 190 is made of glass and is positioned between the eighth lens 180 and the imaging surface 195, without affecting the focal length of the imaging lens system.

[0159] The equations for the aspherical surfaces of the above lenses are expressed as follows:

[0160]

[0161] X: The distance between a point on the aspherical surface at a distance Y from the optical axis and the tangent plane at the intersection point of the aspherical surface and the optical axis.

[0162] Y: The perpendicular distance between a point on the aspherical curve and the optical axis;

[0163] R: Radius of curvature;

[0164] k: cone coefficient; and

[0165] Ai: The i-th order aspherical coefficient.

[0166] In the imaging lens system of the first embodiment, the focal length of the imaging lens system is f, the aperture value (F-number) of the imaging lens system is Fno, and half of the maximum field of view of the imaging lens system is HFOV, with the following values: f = 5.72 mm, Fno = 1.55, HFOV = 22.8 degrees.

[0167] The Abbe number of the eighth lens 180 is V8, which satisfies the following condition: V8 = 18.7.

[0168] The minimum Abbe number of the lenses in the imaging lens system is Vmin, which satisfies the following condition: Vmin = 18.7. In this embodiment, among the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the sixth lens 160, the seventh lens 170, and the eighth lens 180, the Abbe number of the eighth lens 180 is less than the Abbe numbers of the other lenses, therefore Vmin is equal to the Abbe number of the eighth lens 180.

[0169] The Abbe number of the first lens 110 is V1, the Abbe number of the second lens 120 is V2, the Abbe number of the third lens 130 is V3, the Abbe number of the fourth lens 140 is V4, the Abbe number of the fifth lens 150 is V5, the Abbe number of the sixth lens 160 is V6, the Abbe number of the seventh lens 170 is V7, the Abbe number of the eighth lens 180 is V8, and the Abbe number of the i-th lens is Vi, which satisfies the following condition: ΣVi=270.0, where i=1, 2, 3, 4, 5, 6, 7, 8.

[0170] The maximum refractive index of the lenses in the imaging lens system is Nmax, which satisfies the following condition: Nmax = 1.688. In this embodiment, among the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the sixth lens 160, the seventh lens 170, and the eighth lens 180, the refractive index of the eighth lens 180 is greater than that of the other lenses; therefore, Nmax is equal to the refractive index of the eighth lens 180.

[0171] The Abbe number of the first lens 110 is V1, the Abbe number of the second lens 120 is V2, the Abbe number of the third lens 130 is V3, the Abbe number of the fourth lens 140 is V4, the Abbe number of the fifth lens 150 is V5, the Abbe number of the sixth lens 160 is V6, the Abbe number of the seventh lens 170 is V7, the Abbe number of the eighth lens 180 is V8, and the Abbe number of the i-th lens is Vi. The refractive index of the first lens 110 is N1, the refractive index of the second lens 120 is N2, the refractive index of the third lens 130 is N3, the refractive index of the fourth lens 140 is N4, the refractive index of the fifth lens 150 is N5, the refractive index of the sixth lens 160 is N6, the refractive index of the seventh lens 170 is N7, the refractive index of the eighth lens 180 is N8, and the refractive index of the i-th lens is Ni. The minimum value of Vi / Ni is (Vi / Ni)min, which satisfies the following condition: (Vi / Ni)min = 11.08. In this embodiment, (Vi / Ni)min is equal to V8 / N8.

[0172] The sum of the lens thicknesses of all lenses in the imaging lens system along the optical axis is ΣCT, and the sum of the distances between any two adjacent lenses along the optical axis is ΣAT, which satisfies the following condition: ΣCT / ΣAT = 1.55. In this embodiment, the distance between two adjacent lenses along the optical axis refers to the air gap between two adjacent lenses along the optical axis. Furthermore, in this embodiment, ΣCT is the sum of the lens thicknesses of the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the sixth lens 160, the seventh lens 170, and the eighth lens 180; ΣAT is the sum of the distances between the first lens 110 and the second lens 120, the second lens 120 and the third lens 130, the third lens 130 and the fourth lens 140, the fourth lens 140 and the fifth lens 150, the fifth lens 150 and the sixth lens 160, the sixth lens 160 and the seventh lens 170, and the seventh lens 170 and the eighth lens 180 along the optical axis.

[0173] The radius of curvature of the object-side surface 111 of the first lens is R1, and the thickness of the first lens 110 on the optical axis is CT1, which satisfies the following condition: R1 / CT1=2.02.

[0174] The distance from the image-side surface 182 of the eighth lens to the imaging plane 195 on the optical axis is BL, and the thickness of the first lens 110 on the optical axis is CT1, which satisfies the following condition: BL / CT1=0.37.

[0175] The radius of curvature of the image-side surface 142 of the fourth lens is R8, and the focal length of the imaging lens system is f, which satisfies the following condition: R8 / f = 0.47.

[0176] The radius of curvature of the object-side surface 161 of the sixth lens is R11, and the radius of curvature of the image-side surface 162 of the sixth lens is R12, which satisfies the following condition: (R11+R12) / (R11-R12)=2.23.

[0177] The radius of curvature of the object-side surface 171 of the seventh lens is R13, and the radius of curvature of the image-side surface 172 of the seventh lens is R14, which satisfies the following condition: (R13-R14) / (R13+R14)=0.13.

[0178] The focal length of the imaging lens system is f, and the focal length of the first lens 110 is f1, which satisfies the following condition: f / f1=0.94.

[0179] The focal length of the imaging lens system is f, and the focal length of the fifth lens 150 is f5, which satisfies the following condition: f / f5 = 0.17.

[0180] The fifth lens 150 has a focal length of f5, and the seventh lens 170 has a focal length of f7. They satisfy the following condition: f5 / f7 = -2.32.

[0181] The fifth lens 150 has a focal length of f5, and the eighth lens 180 has a focal length of f8, which satisfies the following condition: f8 / f5 = -0.17.

[0182] The focal length of the imaging lens system is f, the focal length of the fifth lens 150 is f5, and the focal length of the sixth lens 160 is f6. It satisfies the following condition: f / f5 + f / f6 = 0.37.

[0183] The maximum imaging height of the imaging lens system is ImgH, which satisfies the following condition: ImgH = 2.39 [mm].

[0184] The distance on the optical axis from the object-side surface 111 of the first lens to the imaging plane 195 is TL, which satisfies the following condition: TL = 5.54 mm.

[0185] The distance on the optical axis from the object-side surface 111 of the first lens to the imaging plane 195 is TL, and the focal length of the imaging lens system is f, which satisfies the following condition: TL / f = 0.97.

[0186] The distance on the optical axis from the object-side surface 111 of the first lens to the imaging surface 195 is TL, and the entrance pupil diameter of the imaging lens system is EPD, which satisfies the following condition: TL / EPD = 1.50.

[0187] The distance from aperture 100 to imaging plane 195 on the optical axis is SL, and the distance from the object-side surface 111 of the first lens to imaging plane 195 on the optical axis is TL, which satisfies the following condition: SL / TL = 0.69.

[0188] The distance on the optical axis from the image-side surface 182 of the eighth lens to the imaging plane 195 is BL, and the distance on the optical axis from the object-side surface 111 of the first lens to the image-side surface 182 of the eighth lens is TD, which satisfies the following condition: BL / TD = 0.07.

[0189] The entrance pupil diameter of the imaging lens system is EPD, and the maximum imaging height of the imaging lens system is ImgH, which satisfies the following condition: EPD / ImgH=1.54.

[0190] The entrance pupil diameter of the imaging lens system is EPD, and the distance on the optical axis from the image-side surface 182 of the eighth lens to the imaging plane 195 is BL, which satisfies the following condition: EPD / BL=10.32.

[0191] The focal length of the imaging lens system is f, and the entrance pupil diameter of the imaging lens system is EPD, which satisfies the following condition: f / EPD = 1.55.

[0192] The maximum effective radius of the object-side surface 111 of the first lens is Y11, the maximum imaging height of the imaging lens system is ImgH, and the entrance pupil diameter of the imaging lens system is EPD, which satisfies the following condition: (Y11-ImgH) / EPD=-0.12.

[0193] The focal length of the imaging lens system is f, half of the maximum field of view in the imaging lens system is HFOV, and the entrance pupil diameter of the imaging lens system is EPD, which satisfies the following condition: f×tan(HFOV) / EPD=0.65.

[0194] The maximum effective radius of the object-side surface 111 of the first lens is Y11, the maximum effective radius of the image-side surface 182 of the eighth lens is Y82, the distance from the image-side surface 182 of the eighth lens to the imaging plane 195 on the optical axis is BL, and the focal length of the imaging lens system is f, which satisfies the following condition: (|Y11-Y82|+BL) / f=0.11.

[0195] The maximum effective radius of the object-side surface 111 of the first lens is Y11, the maximum effective radius of the object-side surface 151 of the fifth lens is Y51, and the maximum effective radius of the image-side surface 182 of the eighth lens is Y82, which satisfies the following condition: (Y82-Y51) / (Y11-Y51)=1.35.

[0196] The maximum effective radius of the object-side surface 111 of the first lens is Y11, the maximum effective radius of the image-side surface 182 of the eighth lens is Y82, the maximum imaging height of the imaging lens system is ImgH, and the focal length of the imaging lens system is f, which satisfies the following condition: (|Y11-Y82|+|Y82-ImgH|) / f=0.08.

[0197] The focal length of the imaging lens system is f, and the maximum imaging height of the imaging lens system is ImgH, which satisfies the following condition: f / ImgH=2.39.

[0198] The critical point of the image-side surface 172 of the seventh lens is perpendicular to the optical axis at a distance of Yc72. The focal length of the imaging lens system is f, which satisfies the following condition: Yc72 / f = 0.18.

[0199] The focal length of the imaging lens system is f, the radius of curvature of the object-side surface 111 of the first lens is R1, and the radius of curvature of the image-side surface 112 of the first lens is R2, which satisfies the following condition: |f / R1|+|f / R2|=4.47.

[0200] The focal length of the imaging lens system is f, the radius of curvature of the object-side surface 121 of the second lens is R3, and the radius of curvature of the image-side surface 122 of the second lens is R4, which satisfies the following condition: |f / R3|+|f / R4|=1.94.

[0201] The focal length of the imaging lens system is f, the radius of curvature of the object-side surface 131 of the third lens is R5, and the radius of curvature of the image-side surface 132 of the third lens is R6. They satisfy the following condition: |f / R5|+|f / R6|=2.92.

[0202] The focal length of the imaging lens system is f, the radius of curvature of the object-side surface 141 of the fourth lens is R7, and the radius of curvature of the image-side surface 142 of the fourth lens is R8. They satisfy the following condition: |f / R7|+|f / R8|=3.14.

[0203] The focal length of the imaging lens system is f, the radius of curvature of the object-side surface 151 of the fifth lens is R9, and the radius of curvature of the image-side surface 152 of the fifth lens is R10. They satisfy the following condition: |f / R9|+|f / R10|=1.56.

[0204] The focal length of the imaging lens system is f, the radius of curvature of the object-side surface 161 of the sixth lens is R11, and the radius of curvature of the image-side surface 162 of the sixth lens is R12. They satisfy the following condition: |f / R11|+|f / R12|=0.66.

[0205] The focal length of the imaging lens system is f, the radius of curvature of the object-side surface 171 of the seventh lens is R13, and the radius of curvature of the image-side surface 172 of the seventh lens is R14. They satisfy the following condition: |f / R13|+|f / R14|=6.46.

[0206] The focal length of the imaging lens system is f, the radius of curvature of the object-side surface 181 of the eighth lens is R15, and the radius of curvature of the image-side surface 182 of the eighth lens is R16. They satisfy the following condition: |f / R15|+|f / R16|=1.61.

[0207] The Abbe number of the first lens 110 is V1, and the refractive index of the first lens 110 is N1, which satisfies the following condition: V1 / N1 = 36.30.

[0208] The Abbe number of the second lens 120 is V2, and the refractive index of the second lens 120 is N2, which satisfies the following condition: V2 / N2 = 36.30.

[0209] The Abbe number of the third lens 130 is V3, and the refractive index of the third lens 130 is N3, which satisfies the following condition: V3 / N3 = 11.66.

[0210] The Abbe number of the fourth lens 140 is V4, and the refractive index of the fourth lens 140 is N4, which satisfies the following condition: V4 / N4 = 14.34.

[0211] The Abbe number of the fifth lens 150 is V5, and the refractive index of the fifth lens 150 is N5, which satisfies the following condition: V5 / N5 = 13.01.

[0212] The Abbe number of the sixth lens 160 is V6, and the refractive index of the sixth lens 160 is N6, which satisfies the following condition: V6 / N6 = 11.24.

[0213] The Abbe number of the seventh lens 170 is V7, and the refractive index of the seventh lens 170 is N7, which satisfies the following condition: V7 / N7 = 36.23.

[0214] The Abbe number of the eighth lens 180 is V8, and the refractive index of the eighth lens 180 is N8, which satisfies the following condition: V8 / N8 = 11.08.

[0215] Please refer to Table 1 and Table 2 below.

[0216]

[0217]

[0218]

[0219] Table 1 is... Figure 1 The first embodiment provides detailed structural data, where the units for radius of curvature, thickness, and focal length are millimeters (mm), and surfaces 0 to 20 sequentially represent surfaces from the object side to the image side. Table 2 shows the aspherical data in the first embodiment, where k is the cone coefficient in the aspherical curve equation, and A4 to A18 represent the 4th to 18th order aspherical coefficients of each surface. Furthermore, the tables for the following embodiments are corresponding schematic diagrams and aberration curves for each embodiment. The definitions of the data in the tables are the same as those in Tables 1 and 2 of the first embodiment, and will not be repeated here.

[0220] <Second Embodiment>

[0221] Please refer to Figures 3 to 4 ,in Figure 3 A schematic diagram of an image-capturing device according to a second embodiment of the present invention is shown. Figure 4 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the second embodiment. Figure 3 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 299. The imaging lens system, from the object side to the image side, sequentially includes a first lens 210, a second lens 220, an aperture 200, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, a seventh lens 270, an eighth lens 280, a filter element 290, and an imaging surface 295. The electronic photosensitive element 299 is disposed on the imaging surface 295. The imaging lens system includes eight lenses (210, 220, 230, 240, 250, 260, 270, 280), and there are no other interposed lenses between the lenses.

[0222] The first lens 210 has positive refractive power and is made of plastic. Its object-side surface 211 is convex near the optical axis, and its image-side surface 212 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 211 has one inflection point, and its image-side surface 212 has three inflection points.

[0223] The second lens 220 has negative refractive power and is made of plastic. Its object-side surface 221 is concave near the optical axis, and its image-side surface 222 is convex near the optical axis. Both surfaces are aspherical, and its object-side surface 221 has a point of inflection.

[0224] The third lens 230 has negative refractive power and is made of plastic. Its object-side surface 231 is convex near the optical axis, and its image-side surface 232 is concave near the optical axis. Both of its surfaces are aspherical.

[0225] The fourth lens 240 has negative refractive power and is made of plastic. Its object-side surface 241 is convex near the optical axis, and its image-side surface 242 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 241 has a point of inflection, and its image-side surface 242 has a point of inflection.

[0226] The fifth lens 250 has positive refractive power and is made of plastic. Its object-side surface 251 is convex near the optical axis, and its image-side surface 252 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 251 has two inflection points, and its image-side surface 252 has two inflection points.

[0227] The sixth lens 260 has positive refractive power and is made of plastic. Its object-side surface 261 is concave near the optical axis, and its image-side surface 262 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 261 has two inflection points, and its image-side surface 262 has two inflection points.

[0228] The seventh lens 270 has positive refractive power and is made of plastic. Its object-side surface 271 is convex near the optical axis, and its image-side surface 272 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 271 has two inflection points, its image-side surface 272 has two inflection points, and its image-side surface 272 has at least one critical point off-axis.

[0229] The eighth lens 280 has negative refractive power and is made of plastic. Its object-side surface 281 is concave near the optical axis, and its image-side surface 282 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 281 has a point of inflection, and its image-side surface 282 has a point of inflection.

[0230] The filter element 290 is made of glass and is positioned between the eighth lens 280 and the imaging surface 295, without affecting the focal length of the imaging lens system.

[0231] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V8 / N8. The Abbe number of the eighth lens 280 is V8, and the refractive index of the eighth lens 280 is N8.

[0232] Please refer to Table 3 and Table 4 below.

[0233]

[0234]

[0235]

[0236]

[0237] In the second embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0238]

[0239]

[0240] <Third Embodiment>

[0241] Please refer to Figures 5 to 6 ,in Figure 5 A schematic diagram of an image-capturing device according to a third embodiment of the present invention is shown. Figure 6 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the third embodiment. Figure 5 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 399. The imaging lens system, from the object side to the image side, sequentially includes a first lens 310, a second lens 320, an aperture 300, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, a seventh lens 370, an eighth lens 380, a filter element 390, and an imaging surface 395. The electronic photosensitive element 399 is disposed on the imaging surface 395. The imaging lens system includes eight lenses (310, 320, 330, 340, 350, 360, 370, 380), and there are no other interposed lenses between the lenses.

[0242] The first lens 310 has positive refractive power and is made of plastic. Its object-side surface 311 is convex near the optical axis, and its image-side surface 312 is concave near the optical axis. Both of its surfaces are aspherical.

[0243] The second lens 320 has positive refractive power and is made of plastic. Its object-side surface 321 is convex near the optical axis, and its image-side surface 322 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 321 has one inflection point, and its image-side surface 322 has two inflection points.

[0244] The third lens 330 has negative refractive power and is made of plastic. Its object-side surface 331 is convex near the optical axis, and its image-side surface 332 is concave near the optical axis. Both of its surfaces are aspherical.

[0245] The fourth lens 340 has negative refractive power and is made of plastic. Its object-side surface 341 is convex near the optical axis, and its image-side surface 342 is concave near the optical axis. Both surfaces are aspherical, and its image-side surface 342 has a point of inflection.

[0246] The fifth lens 350 has positive refractive power and is made of plastic. Its object-side surface 351 is convex near the optical axis, and its image-side surface 352 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 351 has two inflection points, and its image-side surface 352 has two inflection points.

[0247] The sixth lens 360 has positive refractive power and is made of plastic. Its object-side surface 361 is convex near the optical axis, and its image-side surface 362 is flat near the optical axis. Both surfaces are aspherical. Its object-side surface 361 has three inflection points, and its image-side surface 362 has three inflection points.

[0248] The seventh lens 370 has negative refractive power and is made of plastic. Its object-side surface 371 is convex near the optical axis, and its image-side surface 372 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 371 has three inflection points, its image-side surface 372 has two inflection points, and its image-side surface 372 has at least one critical point off-axis.

[0249] The eighth lens 380 has negative refractive power and is made of plastic. Its object-side surface 381 is concave near the optical axis, and its image-side surface 382 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 381 has four inflection points, and its image-side surface 382 has four inflection points.

[0250] The filter element 390 is made of glass and is positioned between the eighth lens 380 and the imaging surface 395, without affecting the focal length of the imaging lens system.

[0251] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V8 / N8. The Abbe number of the eighth lens 380 is V8, and the refractive index of the eighth lens 380 is N8.

[0252] The focal length of the imaging lens system is f. The radius of curvature of the object-side surface of one lens in the imaging lens system is Ro, and the radius of curvature of the image-side surface of the lens is Ri. Furthermore, one of the eight lenses (310, 320, 330, 340, 350, 360, 370, 380) (the sixth lens 360) satisfies |f / Ro| + |f / Ri| < 0.50. More specifically, the radius of curvature of the object-side surface 361 of the sixth lens is R11, and the radius of curvature of the image-side surface 362 of the sixth lens is R12, and |f / R11| + |f / R12| = 0.26.

[0253] Please refer to Table 5 and Table 6 below.

[0254]

[0255]

[0256]

[0257]

[0258] In the third embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0259]

[0260]

[0261] <Fourth Embodiment>

[0262] Please refer to Figures 7 to 8 ,in Figure 7 A schematic diagram of an image-capturing device according to a fourth embodiment of the present invention is shown. Figure 8 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the fourth embodiment. Figure 7 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 499. The imaging lens system, from the object side to the image side, sequentially includes a first lens 410, an aperture 400, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, a seventh lens 470, an eighth lens 480, a filter element 490, and an imaging surface 495. The electronic photosensitive element 499 is disposed on the imaging surface 495. The imaging lens system includes eight lenses (410, 420, 430, 440, 450, 460, 470, 480), and there are no other interposed lenses between the lenses.

[0263] The first lens 410 has positive refractive power and is made of plastic. Its object-side surface 411 is convex near the optical axis, and its image-side surface 412 is concave near the optical axis. Both surfaces are aspherical, and its image-side surface 412 has a point of inflection.

[0264] The second lens 420 has positive refractive power and is made of plastic. Its object-side surface 421 is convex near the optical axis, and its image-side surface 422 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 421 has a point of inflection, and its image-side surface 422 has a point of inflection.

[0265] The third lens 430 has negative refractive power and is made of plastic. Its object-side surface 431 is convex near the optical axis, and its image-side surface 432 is concave near the optical axis. Both of its surfaces are aspherical.

[0266] The fourth lens 440 has negative refractive power and is made of plastic. Its object-side surface 441 is convex near the optical axis, and its image-side surface 442 is concave near the optical axis. Both surfaces are aspherical, and its image-side surface 442 has a point of inflection.

[0267] The fifth lens 450 has positive refractive power and is made of plastic. Its object-side surface 451 is convex near the optical axis, and its image-side surface 452 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 451 has one inflection point, and its image-side surface 452 has three inflection points.

[0268] The sixth lens 460 has negative refractive power and is made of plastic. Its object-side surface 461 is convex near the optical axis, and its image-side surface 462 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 461 has three inflection points, and its image-side surface 462 has three inflection points.

[0269] The seventh lens 470 has positive refractive power and is made of plastic. Its object-side surface 471 is convex near the optical axis, and its image-side surface 472 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 471 has three inflection points, its image-side surface 472 has two inflection points, and its image-side surface 472 has at least one critical point off-axis.

[0270] The eighth lens 480 has negative refractive power and is made of plastic. Its object-side surface 481 is concave near the optical axis, and its image-side surface 482 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 481 has four inflection points, and its image-side surface 482 has four inflection points.

[0271] The filter element 490 is made of glass and is positioned between the eighth lens 480 and the imaging surface 495, without affecting the focal length of the imaging lens system.

[0272] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V8 / N8. The Abbe number of the eighth lens 480 is V8, and the refractive index of the eighth lens 480 is N8.

[0273] The focal length of the imaging lens system is f. The radius of curvature of the object-side surface of one lens in the imaging lens system is Ro, and the radius of curvature of the image-side surface of the lens is Ri. Among the eight lenses (410, 420, 430, 440, 450, 460, 470, 480), one lens (the sixth lens 460) satisfies |f / Ro| + |f / Ri| < 0.50. Furthermore, the radius of curvature of the object-side surface 461 of the sixth lens is R11, and the radius of curvature of the image-side surface 462 of the sixth lens is R12, and |f / R11| + |f / R12| = 0.09.

[0274] Please refer to Tables 7 and 8 below.

[0275]

[0276]

[0277]

[0278]

[0279] In the fourth embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0280]

[0281]

[0282] <Fifth Embodiment>

[0283] Please refer to Figures 9 to 10 ,in Figure 9 A schematic diagram of an image-capturing device according to a fifth embodiment of the present invention is shown. Figure 10 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the fifth embodiment. Figure 9 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 599. The imaging lens system, from the object side to the image side, sequentially includes a first lens 510, an aperture 500, a second lens 520, a third lens 530, a fourth lens 540, a fifth lens 550, a sixth lens 560, a seventh lens 570, an eighth lens 580, a filter element 590, and an imaging surface 595. The electronic photosensitive element 599 is disposed on the imaging surface 595. The imaging lens system includes eight lenses (510, 520, 530, 540, 550, 560, 570, and 580), and there are no other interposed lenses between the lenses.

[0284] The first lens 510 has positive refractive power and is made of plastic. Its object-side surface 511 is convex near the optical axis, and its image-side surface 512 is concave near the optical axis. Both of its surfaces are aspherical.

[0285] The second lens 520 has positive refractive power and is made of plastic. Its object-side surface 521 is convex near the optical axis, and its image-side surface 522 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 521 has a point of inflection, and its image-side surface 522 has a point of inflection.

[0286] The third lens 530 has negative refractive power and is made of plastic. Its object-side surface 531 is convex near the optical axis, and its image-side surface 532 is concave near the optical axis. Both surfaces are aspherical, and its object-side surface 531 has a point of inflection.

[0287] The fourth lens 540 has negative refractive power and is made of plastic. Its object-side surface 541 is convex near the optical axis, and its image-side surface 542 is concave near the optical axis. Both surfaces are aspherical, and its image-side surface 542 has two inflection points.

[0288] The fifth lens 550 has positive refractive power and is made of plastic. Its object-side surface 551 is convex near the optical axis, and its image-side surface 552 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 551 has one inflection point, and its image-side surface 552 has three inflection points.

[0289] The sixth lens 560 has positive refractive power and is made of plastic. Its object-side surface 561 is convex near the optical axis, and its image-side surface 562 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 561 has three inflection points, and its image-side surface 562 has two inflection points.

[0290] The seventh lens 570 has negative refractive power and is made of plastic. Its object-side surface 571 is convex near the optical axis, and its image-side surface 572 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 571 has three inflection points, its image-side surface 572 has two inflection points, and its image-side surface 572 has at least one critical point off-axis.

[0291] The eighth lens 580 has negative refractive power and is made of plastic. Its object-side surface 581 is convex near the optical axis, and its image-side surface 582 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 581 has four inflection points, and its image-side surface 582 has three inflection points.

[0292] The filter element 590 is made of glass and is positioned between the eighth lens 580 and the imaging surface 595, without affecting the focal length of the imaging lens system.

[0293] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V8 / N8. The Abbe number of the eighth lens 580 is V8, and the refractive index of the eighth lens 580 is N8.

[0294] The focal length of the imaging lens system is f. The radius of curvature of the object-side surface of one lens in the imaging lens system is Ro, and the radius of curvature of the image-side surface of the lens is Ri. One of the eight lenses (510, 520, 530, 540, 550, 560, 570, 580) (the sixth lens 560) satisfies |f / Ro| + |f / Ri| < 0.50. Furthermore, the radius of curvature of the object-side surface 561 of the sixth lens is R11, and the radius of curvature of the image-side surface 562 of the sixth lens is R12, and |f / R11| + |f / R12| = 0.19. Please refer to Tables 9 and 10 below.

[0295]

[0296]

[0297]

[0298]

[0299] In the fifth embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0300]

[0301]

[0302] <Sixth Embodiment>

[0303] Please refer to Figures 11 to 12 ,in Figure 11 A schematic diagram of an image-capturing device according to a sixth embodiment of the present invention is shown. Figure 12 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the sixth embodiment. Figure 11As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 699. The imaging lens system, from the object side to the image side, sequentially includes a first lens 610, a second lens 620, an aperture 600, a third lens 630, a fourth lens 640, a fifth lens 650, a sixth lens 660, a seventh lens 670, an eighth lens 680, a filter element 690, and an imaging surface 695. The electronic photosensitive element 699 is disposed on the imaging surface 695. The imaging lens system includes eight lenses (610, 620, 630, 640, 650, 660, 670, 680), and there are no other interposed lenses between the lenses.

[0304] The first lens 610 has positive refractive power and is made of plastic. Its object-side surface 611 is convex near the optical axis, and its image-side surface 612 is concave near the optical axis. Both surfaces are aspherical, and its object-side surface 611 has a point of inflection.

[0305] The second lens 620 has positive refractive power and is made of plastic. Its object-side surface 621 is convex near the optical axis, and its image-side surface 622 is convex near the optical axis. Both surfaces are aspherical, and its image-side surface 622 has two inflection points.

[0306] The third lens 630 has negative refractive power and is made of plastic. Its object-side surface 631 is convex near the optical axis, and its image-side surface 632 is concave near the optical axis. Both of its surfaces are aspherical.

[0307] The fourth lens 640 has negative refractive power and is made of plastic. Its object-side surface 641 is convex near the optical axis, and its image-side surface 642 is concave near the optical axis. Both surfaces are aspherical, and its image-side surface 642 has a point of inflection.

[0308] The fifth lens 650 has positive refractive power and is made of plastic. Its object-side surface 651 is convex near the optical axis, and its image-side surface 652 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 651 has one inflection point, and its image-side surface 652 has three inflection points.

[0309] The sixth lens 660 has positive refractive power and is made of plastic. Its object-side surface 661 is convex near the optical axis, and its image-side surface 662 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 661 has three inflection points, and its image-side surface 662 has two inflection points.

[0310] The seventh lens 670 has negative refractive power and is made of plastic. Its object-side surface 671 is convex near the optical axis, and its image-side surface 672 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 671 has three inflection points, its image-side surface 672 has one inflection point, and its image-side surface 672 has at least one critical point off-axis.

[0311] The eighth lens 680 has positive refractive power and is made of plastic. Its object-side surface 681 is concave near the optical axis, and its image-side surface 682 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 681 has four inflection points, and its image-side surface 682 has six inflection points.

[0312] The filter element 690 is made of glass and is positioned between the eighth lens 680 and the imaging surface 695, without affecting the focal length of the imaging lens system.

[0313] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V8 / N8. The Abbe number of the eighth lens 680 is V8, and the refractive index of the eighth lens 680 is N8.

[0314] The focal length of the imaging lens system is f. The radius of curvature of the object-side surface of one lens in the imaging lens system is Ro, and the radius of curvature of the image-side surface of the lens is Ri. Two of the eight lenses (610, 620, 630, 640, 650, 660, 670, 680) (the sixth lens 660 and the eighth lens 680) satisfy |f / Ro| + |f / Ri| < 0.50. Further, the radius of curvature of the object-side surface 661 of the sixth lens is R11, and the radius of curvature of the image-side surface 662 of the sixth lens is R12, and |f / R11| + |f / R12| = 0.14; the radius of curvature of the object-side surface 681 of the eighth lens is R15, and the radius of curvature of the image-side surface 682 of the eighth lens is R16, and |f / R15| + |f / R16| = 0.31.

[0315] Please refer to Table 11 and Table 12 below.

[0316]

[0317]

[0318]

[0319]

[0320] In the sixth embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0321]

[0322]

[0323] <Seventh Embodiment>

[0324] Please refer to Figures 13 to 14 ,in Figure 13 A schematic diagram of an image-capturing device according to a seventh embodiment of the present invention is shown. Figure 14 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the seventh embodiment. Figure 13 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 799. The imaging lens system, from the object side to the image side, sequentially includes a first lens 710, a second lens 720, an aperture 700, a third lens 730, a fourth lens 740, a fifth lens 750, a sixth lens 760, a seventh lens 770, an eighth lens 780, a filter element 790, and an imaging surface 795. The electronic photosensitive element 799 is disposed on the imaging surface 795. The imaging lens system includes eight lenses (710, 720, 730, 740, 750, 760, 770, 780), and there are no other interposed lenses between the lenses.

[0325] The first lens 710 has positive refractive power and is made of plastic. Its object-side surface 711 is convex near the optical axis, and its image-side surface 712 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 711 has a point of inflection, and its image-side surface 712 has a point of inflection.

[0326] The second lens 720 has positive refractive power and is made of plastic. Its object-side surface 721 is convex near the optical axis, and its image-side surface 722 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 721 has one inflection point, and its image-side surface 722 has two inflection points.

[0327] The third lens 730 has negative refractive power and is made of plastic. Its object-side surface 731 is concave near the optical axis, and its image-side surface 732 is concave near the optical axis. Both surfaces are aspherical, and its object-side surface 731 has a point of inflection.

[0328] The fourth lens 740 has positive refractive power and is made of plastic. Its object-side surface 741 is convex near the optical axis, and its image-side surface 742 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 741 has three inflection points, and its image-side surface 742 has one inflection point.

[0329] The fifth lens 750 has negative refractive power and is made of plastic. Its object-side surface 751 is concave near the optical axis, and its image-side surface 752 is concave near the optical axis. Both surfaces are aspherical, and its image-side surface 752 has two inflection points.

[0330] The sixth lens 760 has positive refractive power and is made of plastic. Its object-side surface 761 is concave near the optical axis, and its image-side surface 762 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 761 has two inflection points, and its image-side surface 762 has two inflection points.

[0331] The seventh lens 770 has negative refractive power and is made of plastic. Its object-side surface 771 is convex near the optical axis, and its image-side surface 772 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 771 has two inflection points, its image-side surface 772 has one inflection point, and its image-side surface 772 has at least one critical point off-axis.

[0332] The eighth lens 780 has negative refractive power and is made of plastic. Its object-side surface 781 is convex near the optical axis, and its image-side surface 782 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 781 has six inflection points, and its image-side surface 782 has four inflection points.

[0333] The filter element 790 is made of glass and is positioned between the eighth lens 780 and the imaging surface 795, without affecting the focal length of the imaging lens system.

[0334] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V8 / N8. The Abbe number of the eighth lens 780 is V8, and the refractive index of the eighth lens 780 is N8.

[0335] Please refer to Tables 13 and 14 below.

[0336]

[0337]

[0338]

[0339]

[0340] In the seventh embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0341]

[0342]

[0343] <Eighth Embodiment>

[0344] Please refer to Figures 15 to 16 ,in Figure 15 A schematic diagram of an image-capturing device according to an eighth embodiment of the present invention is shown. Figure 16 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the eighth embodiment. Figure 15 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 899. The imaging lens system, from the object side to the image side, includes, in sequence, an aperture 800, a first lens 810, a second lens 820, a third lens 830, a fourth lens 840, a fifth lens 850, a sixth lens 860, a seventh lens 870, an eighth lens 880, a filter element 890, and an imaging surface 895. The electronic photosensitive element 899 is disposed on the imaging surface 895. The imaging lens system includes eight lenses (810, 820, 830, 840, 850, 860, 870, and 880), and there are no other interposed lenses between the lenses.

[0345] The first lens 810 has positive refractive power and is made of plastic. Its object-side surface 811 is convex near the optical axis, and its image-side surface 812 is convex near the optical axis. Both surfaces are aspherical, and its image-side surface 812 has a point of inflection.

[0346] The second lens 820 has negative refractive power and is made of plastic. Its object-side surface 821 is convex near the optical axis, and its image-side surface 822 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 821 has three inflection points, and its image-side surface 822 has one inflection point.

[0347] The third lens 830 has positive refractive power and is made of plastic. Its object-side surface 831 is convex near the optical axis, and its image-side surface 832 is concave near the optical axis. Both surfaces are aspherical, and its object-side surface 831 has two inflection points.

[0348] The fourth lens 840 has positive refractive power and is made of plastic. Its object-side surface 841 is convex near the optical axis, and its image-side surface 842 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 841 has a point of inflection, and its image-side surface 842 has a point of inflection.

[0349] The fifth lens 850 has positive refractive power and is made of plastic. Its object-side surface 851 is convex near the optical axis, and its image-side surface 852 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 851 has one inflection point, and its image-side surface 852 has two inflection points.

[0350] The sixth lens 860 has negative refractive power and is made of plastic. Its object-side surface 861 is concave near the optical axis, and its image-side surface 862 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 861 has two inflection points, and its image-side surface 862 has one inflection point.

[0351] The seventh lens 870 has negative refractive power and is made of plastic. Its object-side surface 871 is convex near the optical axis, and its image-side surface 872 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 871 has a point of inflection, its image-side surface 872 has a point of inflection, and its image-side surface 872 has at least one critical point off-axis.

[0352] The eighth lens 880 has positive refractive power and is made of plastic. Its object-side surface 881 is convex near the optical axis, and its image-side surface 882 is concave near the optical axis. Both surfaces are aspherical, and its object-side surface 881 has two inflection points.

[0353] The filter element 890 is made of glass and is located between the eighth lens 880 and the imaging surface 895. It does not affect the focal length of the imaging lens system.

[0354] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V8 / N8. The Abbe number of the eighth lens 880 is V8, and the refractive index of the eighth lens 880 is N8.

[0355] Please refer to Tables 15 and 16 below.

[0356]

[0357]

[0358]

[0359]

[0360] In the eighth embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0361]

[0362]

[0363] <Ninth Embodiment>

[0364] Please refer to Figures 17 to 18 ,in Figure 17 A schematic diagram of an image-capturing device according to a ninth embodiment of the present invention is shown. Figure 18 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the ninth embodiment. Figure 17 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 999. The imaging lens system, from the object side to the image side, includes, in sequence, an aperture 900, a first lens 910, a second lens 920, a third lens 930, an aperture stop 901, a fourth lens 940, a fifth lens 950, a sixth lens 960, a seventh lens 970, an eighth lens 980, a filter element 990, and an imaging surface 995. The electronic photosensitive element 999 is disposed on the imaging surface 995. The imaging lens system includes eight lenses (910, 920, 930, 940, 950, 960, 970, 980), and there are no other interposed lenses between the lenses.

[0365] The first lens 910 has positive refractive power and is made of plastic. Its object-side surface 911 is convex near the optical axis, and its image-side surface 912 is convex near the optical axis. Both surfaces are aspherical, and its image-side surface 912 has a point of inflection.

[0366] The second lens 920 has negative refractive power and is made of plastic. Its object-side surface 921 is convex near the optical axis, and its image-side surface 922 is concave near the optical axis. Both surfaces are aspherical, and its object-side surface 921 has three inflection points.

[0367] The third lens 930 has positive refractive power and is made of plastic. Its object-side surface 931 is convex near the optical axis, and its image-side surface 932 is concave near the optical axis. Both of its surfaces are aspherical.

[0368] The fourth lens 940 has negative refractive power and is made of plastic. Its object-side surface 941 is convex near the optical axis, and its image-side surface 942 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 941 has a point of inflection, and its image-side surface 942 has a point of inflection.

[0369] The fifth lens 950 has positive refractive power and is made of plastic. Its object-side surface 951 is convex near the optical axis, and its image-side surface 952 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 951 has three inflection points, and its image-side surface 952 has one inflection point.

[0370] The sixth lens 960 has negative refractive power and is made of plastic. Its object-side surface 961 is convex near the optical axis, and its image-side surface 962 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 961 has a point of inflection, and its image-side surface 962 has a point of inflection.

[0371] The seventh lens 970 has negative refractive power and is made of plastic. Its object-side surface 971 is convex near the optical axis, and its image-side surface 972 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 971 has two inflection points, its image-side surface 972 has one inflection point, and its image-side surface 972 has at least one critical point off-axis.

[0372] The eighth lens 980 has positive refractive power and is made of plastic. Its object-side surface 981 is convex near the optical axis, and its image-side surface 982 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 981 has three inflection points, and its image-side surface 982 has two inflection points.

[0373] The filter element 990 is made of glass and is located between the eighth lens 980 and the imaging surface 995. It does not affect the focal length of the imaging lens system.

[0374] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V8 / N8. The Abbe number of the eighth lens 980 is V8, and the refractive index of the eighth lens 980 is N8.

[0375] Please refer to Tables 17 and 18 below.

[0376]

[0377]

[0378]

[0379]

[0380] In the ninth embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0381]

[0382]

[0383] <Tenth Embodiment>

[0384] Please refer to Figures 19 to 20,in Figure 19 A schematic diagram of an image-capturing device according to a tenth embodiment of the present invention is shown. Figure 20 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the tenth embodiment. Figure 19 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 1099. The imaging lens system, from the object side to the image side, sequentially includes a first lens 1010, an aperture 1000, a second lens 1020, a third lens 1030, an aperture stop 1001, a fourth lens 1040, a fifth lens 1050, a sixth lens 1060, a seventh lens 1070, an eighth lens 1080, a filter element 1090, and an imaging surface 1095. The electronic photosensitive element 1099 is disposed on the imaging surface 1095. The imaging lens system includes eight lenses (1010, 1020, 1030, 1040, 1050, 1060, 1070, and 1080), and there are no other interposed lenses between the lenses.

[0385] The first lens 1010 has positive refractive power and is made of plastic. Its object-side surface 1011 is convex near the optical axis, and its image-side surface 1012 is convex near the optical axis. Both surfaces are aspherical, and its image-side surface 1012 has a point of inflection.

[0386] The second lens 1020 has negative refractive power and is made of plastic. Its object-side surface 1021 is concave near the optical axis, and its image-side surface 1022 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1021 has a point of inflection, and its image-side surface 1022 has a point of inflection.

[0387] The third lens 1030 has negative refractive power and is made of plastic. Its object-side surface 1031 is concave near the optical axis, and its image-side surface 1032 is concave near the optical axis. Both of its surfaces are aspherical. Its object-side surface 1031 has three inflection points, and its image-side surface 1032 has one inflection point.

[0388] The fourth lens 1040 has positive refractive power and is made of plastic. Its object-side surface 1041 is convex near the optical axis, and its image-side surface 1042 is concave near the optical axis. Both surfaces are aspherical, and its image-side surface 1042 has a point of inflection.

[0389] The fifth lens 1050 has positive refractive power and is made of plastic. Its object-side surface 1051 is convex near the optical axis, and its image-side surface 1052 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1051 has a point of inflection, and its image-side surface 1052 has a point of inflection.

[0390] The sixth lens 1060 has negative refractive power and is made of plastic. Its object-side surface 1061 is concave near the optical axis, and its image-side surface 1062 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 1061 has a point of inflection, and its image-side surface 1062 has a point of inflection.

[0391] The seventh lens 1070 has negative refractive power and is made of plastic. Its object-side surface 1071 is concave near the optical axis, and its image-side surface 1072 is concave near the optical axis. Both surfaces are aspherical. Its image-side surface 1072 has a point of inflection and at least one critical point off-axis.

[0392] The eighth lens 1080 has positive refractive power and is made of plastic. Its object-side surface 1081 is convex near the optical axis, and its image-side surface 1082 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1081 has two inflection points, and its image-side surface 1082 has one inflection point.

[0393] The filter element 1090 is made of glass and is positioned between the eighth lens 1080 and the imaging surface 1095, without affecting the focal length of the imaging lens system.

[0394] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V2 / N2. The Abbe number of the second lens 1020 is V2, and the refractive index of the second lens 1020 is N2.

[0395] Please refer to Tables 19 and 20 below.

[0396]

[0397]

[0398]

[0399]

[0400] In the tenth embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0401]

[0402]

[0403] <Eleventh Embodiment>

[0404] Please refer to Figures 21 to 22 ,in Figure 21 A schematic diagram of an image-capturing device according to the eleventh embodiment of the present invention is shown. Figure 22 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the eleventh embodiment. Figure 21 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 1199. The imaging lens system, from the object side to the image side, sequentially includes a first lens 1110, an aperture 1100, a second lens 1120, a third lens 1130, an aperture stop 1101, a fourth lens 1140, a fifth lens 1150, a sixth lens 1160, a seventh lens 1170, an eighth lens 1180, a filter element 1190, and an imaging surface 1195. The electronic photosensitive element 1199 is disposed on the imaging surface 1195. The imaging lens system includes eight lenses (1110, 1120, 1130, 1140, 1150, 1160, 1170, and 1180), and there are no other interposed lenses between the lenses.

[0405] The first lens 1110 has positive refractive power and is made of plastic. Its object-side surface 1111 is convex near the optical axis, and its image-side surface 1112 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1111 has two inflection points, and its image-side surface 1112 has one inflection point.

[0406] The second lens 1120 has negative refractive power and is made of plastic. Its object-side surface 1121 is concave near the optical axis, and its image-side surface 1122 is concave near the optical axis. Both surfaces are aspherical, and its object-side surface 1121 has a point of inflection.

[0407] The third lens 1130 has positive refractive power and is made of plastic. Its object-side surface 1131 is convex near the optical axis, and its image-side surface 1132 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1131 has one inflection point, and its image-side surface 1132 has two inflection points.

[0408] The fourth lens 1140 has negative refractive power and is made of plastic. Its object-side surface 1141 is concave near the optical axis, and its image-side surface 1142 is concave near the optical axis. Both of its surfaces are aspherical. Its object-side surface 1141 has a point of inflection, and its image-side surface 1142 has a point of inflection.

[0409] The fifth lens 1150 has positive refractive power and is made of plastic. Its object-side surface 1151 is convex near the optical axis, and its image-side surface 1152 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1151 has a point of inflection, and its image-side surface 1152 has a point of inflection.

[0410] The sixth lens 1160 has negative refractive power and is made of plastic. Its object-side surface 1161 is concave near the optical axis, and its image-side surface 1162 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 1161 has one inflection point, and its image-side surface 1162 has two inflection points.

[0411] The seventh lens 1170 has negative refractive power and is made of plastic. Its object-side surface 1171 is concave near the optical axis, and its image-side surface 1172 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 1171 has one inflection point, its image-side surface 1172 has two inflection points, and its image-side surface 1172 has at least one critical point off-axis.

[0412] The eighth lens 1180 has positive refractive power and is made of plastic. Its object-side surface 1181 is convex near the optical axis, and its image-side surface 1182 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1181 has two inflection points, and its image-side surface 1182 has one inflection point.

[0413] The filter element 1190 is made of glass and is positioned between the eighth lens 1180 and the imaging surface 1195, without affecting the focal length of the imaging lens system.

[0414] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V2 / N2. The Abbe number of the second lens 1120 is V2, and the refractive index of the second lens 1120 is N2.

[0415] Please refer to Table 21 and Table 22 below.

[0416]

[0417]

[0418] In the eleventh embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0419]

[0420]

[0421] <Twelfth Embodiment>

[0422] Please refer to Figures 23 to 24 ,in Figure 23 A schematic diagram of an image-capturing device according to the twelfth embodiment of the present invention is shown. Figure 24From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the twelfth embodiment. Figure 23 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 1299. The imaging lens system, from the object side to the image side, sequentially includes a first lens 1210, an aperture 1200, a second lens 1220, a third lens 1230, an aperture stop 1201, a fourth lens 1240, a fifth lens 1250, a sixth lens 1260, a seventh lens 1270, an eighth lens 1280, a filter element 1290, and an imaging surface 1295. The electronic photosensitive element 1299 is disposed on the imaging surface 1295. The imaging lens system includes eight lenses (1210, 1220, 1230, 1240, 1250, 1260, 1270, and 1280), and there are no other interposed lenses between the lenses.

[0423] The first lens 1210 has positive refractive power and is made of plastic. Its object-side surface 1211 is convex near the optical axis, and its image-side surface 1212 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1211 has two inflection points, and its image-side surface 1212 has one inflection point.

[0424] The second lens 1220 has negative refractive power and is made of plastic. Its object-side surface 1221 is concave near the optical axis, and its image-side surface 1222 is concave near the optical axis. Both surfaces are aspherical, and its object-side surface 1221 has a point of inflection.

[0425] The third lens 1230 has positive refractive power and is made of plastic. Its object-side surface 1231 is convex near the optical axis, and its image-side surface 1232 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1231 has a point of inflection, and its image-side surface 1232 has a point of inflection.

[0426] The fourth lens 1240 has negative refractive power and is made of plastic. Its object-side surface 1241 is concave near the optical axis, and its image-side surface 1242 is concave near the optical axis. Both of its surfaces are aspherical. Its object-side surface 1241 has a point of inflection, and its image-side surface 1242 has a point of inflection.

[0427] The fifth lens 1250 has positive refractive power and is made of plastic. Its object-side surface 1251 is convex near the optical axis, and its image-side surface 1252 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 1251 has one inflection point, and its image-side surface 1252 has two inflection points.

[0428] The sixth lens 1260 has negative refractive power and is made of plastic. Its object-side surface 1261 is convex near the optical axis, and its image-side surface 1262 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 1261 has two inflection points, and its image-side surface 1262 has one inflection point.

[0429] The seventh lens 1270 has negative refractive power and is made of plastic. Its object-side surface 1271 is convex near the optical axis, and its image-side surface 1272 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 1271 has two inflection points, its image-side surface 1272 has two inflection points, and its image-side surface 1272 has at least one critical point off-axis.

[0430] The eighth lens 1280 has positive refractive power and is made of plastic. Its object-side surface 1281 is convex near the optical axis, and its image-side surface 1282 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1281 has two inflection points, and its image-side surface 1282 has two inflection points.

[0431] The filter element 1290 is made of glass and is positioned between the eighth lens 1280 and the imaging surface 1295, without affecting the focal length of the imaging lens system.

[0432] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V2 / N2. The Abbe number of the second lens 1220 is V2, and the refractive index of the second lens 1220 is N2.

[0433] Please refer to Table 23 and Table 24 below.

[0434]

[0435]

[0436]

[0437]

[0438] In the twelfth embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0439]

[0440]

[0441] <Thirteenth Embodiment>

[0442] Please refer to Figures 25 to 26 ,in Figure 25 A schematic diagram of an image-capturing device according to a thirteenth embodiment of the present invention is shown. Figure 26 From left to right, the graphs show the spherical aberration, astigmatism, and distortion curves of the thirteenth embodiment. Figure 25 As can be seen, the image capturing device includes an imaging lens system (unlabeled) and an electronic photosensitive element 1399. The imaging lens system, from the object side to the image side, sequentially includes a first lens 1310, an aperture 1300, a second lens 1320, a third lens 1330, an aperture stop 1301, a fourth lens 1340, a fifth lens 1350, a sixth lens 1360, a seventh lens 1370, an eighth lens 1380, a filter element 1390, and an imaging surface 1395. The electronic photosensitive element 1399 is disposed on the imaging surface 1395. The imaging lens system includes eight lenses (1310, 1320, 1330, 1340, 1350, 1360, 1370, and 1380), and there are no other interposed lenses between the lenses.

[0443] The first lens 1310 has positive refractive power and is made of plastic. Its object-side surface 1311 is convex near the optical axis, and its image-side surface 1312 is convex near the optical axis. Both surfaces are aspherical, and its image-side surface 1312 has a point of inflection.

[0444] The second lens 1320 has negative refractive power and is made of plastic. Its object-side surface 1321 is convex near the optical axis, and its image-side surface 1322 is concave near the optical axis. Both surfaces are aspherical, and its object-side surface 1321 has a point of inflection.

[0445] The third lens 1330 has negative refractive power and is made of plastic. Its object-side surface 1331 is convex near the optical axis, and its image-side surface 1332 is concave near the optical axis. Both surfaces are aspherical, and its image-side surface 1332 has a point of inflection.

[0446] The fourth lens 1340 has positive refractive power and is made of plastic. Its object-side surface 1341 is convex near the optical axis, and its image-side surface 1342 is concave near the optical axis. Both surfaces are aspherical, and its image-side surface 1342 has a point of inflection.

[0447] The fifth lens 1350 has positive refractive power and is made of plastic. Its object-side surface 1351 is convex near the optical axis, and its image-side surface 1352 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1351 has a point of inflection, and its image-side surface 1352 has a point of inflection.

[0448] The sixth lens 1360 has negative refractive power and is made of plastic. Its object-side surface 1361 is concave near the optical axis, and its image-side surface 1362 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 1361 has two inflection points, and its image-side surface 1362 has one inflection point.

[0449] The seventh lens 1370 has negative refractive power and is made of plastic. Its object-side surface 1371 is concave near the optical axis, and its image-side surface 1372 is convex near the optical axis. Both surfaces are aspherical. Its object-side surface 1371 has one inflection point, and its image-side surface 1372 has three inflection points.

[0450] The eighth lens 1380 has negative refractive power and is made of plastic. Its object-side surface 1381 is convex near the optical axis, and its image-side surface 1382 is concave near the optical axis. Both surfaces are aspherical. Its object-side surface 1381 has two inflection points, and its image-side surface 1382 has two inflection points.

[0451] The filter element 1390 is made of glass and is positioned between the eighth lens 1380 and the imaging surface 1395, without affecting the focal length of the imaging lens system.

[0452] In this embodiment, the Abbe number of the i-th lens is Vi, the refractive index of the i-th lens is Ni, the minimum value of Vi / Ni is (Vi / Ni)min, and (Vi / Ni)min is equal to V8 / N8. The Abbe number of the eighth lens 1380 is V8, and the refractive index of the eighth lens 1380 is N8.

[0453] Please refer to Tables 25 and 26 below.

[0454]

[0455]

[0456]

[0457]

[0458] In the thirteenth embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions in the table below are the same as in the first embodiment and will not be repeated here.

[0459]

[0460]

[0461] <Fourteenth Embodiment>

[0462] Please refer to Figure 27 ,in Figure 27 A perspective view of an image-capturing device according to a fourteenth embodiment of the present invention is shown. In this embodiment, the image-capturing device 10 is a camera module. The image-capturing device 10 includes an imaging lens 11, a driving device 12, an electronic photosensitive element 13, and an image stabilization module 14. The imaging lens 11 includes an imaging lens system provided by the present invention, a lens barrel (not otherwise labeled) for supporting the imaging lens system, and a support device (Holder Member, not otherwise labeled). The image-capturing device 10 uses the imaging lens 11 to focus light to generate an image, and cooperates with the driving device 12 to focus the image, finally imaging it on the electronic photosensitive element 13 and outputting it as image data.

[0463] The driving device 12 may have an auto-focus function, and its driving method can use a driving system such as a voice coil motor (VCM), microelectromechanical systems (MEMS), piezoelectric systems, and shape memory alloys. The driving device 12 allows the imaging lens 11 to achieve a better imaging position, enabling clear images of the subject at different object distances. In addition, the image capturing device 10 is equipped with a high-brightness and low-noise electronic image sensor 13 (such as CMOS or CCD) located on the imaging surface of the imaging lens system, which can truly present the good image quality of the imaging lens system.

[0464] The image stabilization module 14 can be, for example, an accelerometer, a gyroscope, or a Hall effect sensor. The drive unit 12 can work in conjunction with the image stabilization module 14 to form an optical image stabilization (OIS) device. By adjusting the changes in different axes of the imaging lens 11, it can compensate for the blurry image caused by shaking during shooting, or use image compensation technology in the imaging software to provide electronic image stabilization (EIS) function, further improving the image quality of shooting in dynamic and low-light scenes.

[0465] <Fifteenth Embodiment>

[0466] Please refer to Figures 28 to 30 ,in Figure 28 A perspective view of an electronic device according to a fifteenth embodiment of the present invention is shown. Figure 29 Draw Figure 28 A three-dimensional view of the other side of the electronic device. Figure 30 Draw Figure 28System block diagram of an electronic device.

[0467] In this embodiment, the electronic device 20 is a smartphone. The electronic device 20 includes, according to the fourteenth embodiment, an image capturing device 10, image capturing devices 10a, 10b, and 10c, a flash module 21, a focus assist module 22, an image signal processor 23, a user interface 24, and an image software processor 25. The image capturing device 10c is located on the same side as the user interface 24, while the image capturing devices 10, 10a, and 10b are located on opposite sides of the user interface 24, and all three face the same direction. The image capturing devices 10a, 10b, and 10c have a similar structural configuration to the image capturing device 10. Specifically, each of the image capturing devices 10a, 10b, and 10c includes an imaging lens, a driving device, an electronic photosensitive element, and an image stabilization module. The imaging lenses of imaging devices 10a, 10b and 10c each include an optical lens group, a lens barrel for carrying the lens group and a support device.

[0468] In this embodiment, the image capturing device 10 is a telephoto image capturing device, the image capturing device 10a is a wide-angle image capturing device, and the image capturing device 10b is a standard image capturing device with a viewing angle between that of the image capturing device 10 and the image capturing device 10a. The viewing angles of the image capturing device 10 and the image capturing device 10a can differ by at least 20 degrees. The image capturing devices 10, 10a, and 10b in this embodiment have different viewing angles, allowing the electronic device to provide different magnifications to achieve an optical zoom shooting effect. The electronic device 20 described above is exemplified by including multiple image capturing devices 10, 10a, 10b, and 10c, but the number of image capturing devices is not intended to limit the invention.

[0469] When the user takes a picture of the subject 26, the electronic device 20 uses the image capturing device 10, image capturing device 10a, or image capturing device 10b to focus the light and activate the flash module 21 for supplemental lighting. It then uses the subject distance information of the subject 26 provided by the focus assist module 22 for fast focusing. Furthermore, the image signal processor 23 performs image optimization processing to further improve the image quality produced by the camera lens. The focus assist module 22 can use an infrared or laser focus assist system to achieve fast focusing. Alternatively, the electronic device 20 can also take pictures using the image capturing device 10c. The user interface 24 can use a touch screen or a physical shooting button, combined with the diverse functions of the image software processor 25 for image capture and image processing. The image processed by the image software processor 25 can be displayed on the user interface 24.

[0470] The image capturing device 10 of the present invention is not limited to application in smartphones. The image capturing device 10 can also be applied to mobile focusing systems as needed, and features excellent aberration correction and good image quality. For example, the image capturing device 10 can be widely used in electronic devices such as three-dimensional (3D) image capture, digital cameras, mobile devices, tablet computers, smart TVs, network monitoring equipment, dashcam reversing cameras, multi-lens devices, recognition systems, motion-sensing game consoles, and wearable devices. The above-mentioned electronic devices are merely illustrative examples of practical applications of the present invention and do not limit the scope of application of the image capturing device of the present invention.

[0471] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. An imaging lens system, characterized in that, The imaging lens system includes eight lenses, which are sequentially arranged from the object side to the image side as 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. Each of the eight lenses has an object-side surface facing the object side and an image-side surface facing the image side. The first lens has positive refractive power, and the object-side surface of the first lens is convex near the optical axis. The eighth lens has negative refractive power, and at least one surface of at least one lens in the imaging lens system has at least one inflection point. The imaging lens system comprises eight lenses in total. The Abbe number of the first lens is V1, the second lens is V2, the third lens is V3, the fourth lens is V4, the fifth lens is V5, the sixth lens is V6, the seventh lens is V7, the eighth lens is V8, and the Abbe number of the i-th lens is Vi. The minimum Abbe number of the lenses in the imaging lens system is Vmin. The distance from the object-side surface of the first lens to an imaging plane on the optical axis is TL. The focal length of the imaging lens system is f. The distance from the image-side surface of the eighth lens to the imaging plane on the optical axis is BL; the distance from the object-side surface of the first lens to the image-side surface of the eighth lens on the optical axis is TD; the refractive index of the first lens is N1; the refractive index of the second lens is N2; the refractive index of the third lens is N3; the refractive index of the fourth lens is N4; the refractive index of the fifth lens is N5; the refractive index of the sixth lens is N6; the refractive index of the seventh lens is N7; the refractive index of the eighth lens is N8; the refractive index of the i-th lens is Ni; and the minimum value of Vi / Ni is (Vi / Ni)min, which satisfies the following condition: 8.0 < Vmin < 20.0; 0.50 < TL / f < 1.10; 0 < BL / TD < 0.30; and 9.0 < (Vi / Ni)min < 11.80, where i = 1, 2, 3, 4, 5, 6, 7, 8.

2. The imaging lens system according to claim 1, characterized in that, The image-side surface of the eighth lens is concave near the optical axis, and at least one surface of each of the at least three lenses in the imaging lens system has at least one inflection point.

3. The imaging lens system according to claim 1, characterized in that, The image-side surface of the seventh lens is concave near the optical axis. A critical point on the image-side surface of the seventh lens is perpendicular to the optical axis at a distance of Yc72. The focal length of the imaging lens system is f, and it satisfies the following conditions: 0.02 < Yc72 / f < 0.

70.

4. The imaging lens system according to claim 1, characterized in that, The distance along the optical axis from the object-side surface of the first lens to the imaging surface is TL, and the entrance pupil diameter of the imaging lens system is EPD, which satisfies the following conditions: 1.10 < TL / EPD < 1.

90.

5. The imaging lens system according to claim 1, characterized in that, In this imaging lens system, at least four lenses have an Abbe number of less than 35.

0.

6. The imaging lens system according to claim 1, characterized in that, The minimum Abbe number of the lenses in this imaging lens system is Vmin, the distance from the object-side surface of the first lens to the imaging surface on the optical axis is TL, the focal length of the imaging lens system is f, the distance from the image-side surface of the eighth lens to the imaging surface on the optical axis is BL, and the distance from the object-side surface of the first lens to the image-side surface of the eighth lens on the optical axis is TD. These conditions must be met: 10.0 < Vmin < 20.0; 0.97 ≤ TL / f < 1.10; and 0.07 ≤ BL / TD < 0.

25.

7. The imaging lens system according to claim 1, characterized in that, The object-side surface of the third lens is convex near the optical axis, and the image-side surface of the third lens is concave near the optical axis.

8. The imaging lens system according to claim 1, characterized in that, The Abbe number of the eighth lens is V8, and it satisfies the following condition: 8.0 < V8 < 24.5。 9. The imaging lens system according to claim 1, characterized in that, The entrance pupil diameter of the imaging lens system is EPD, and the distance from the image-side surface of the eighth lens to the imaging plane on the optical axis is BL, which satisfies the following conditions: 4.50 < EPD / BL ≤ 10.

32.

10. The imaging lens system according to claim 1, characterized in that, The minimum Abbe number of the lenses in this imaging lens system is Vmin, the distance from the object-side surface of the first lens to the imaging surface on the optical axis is TL, the focal length of the imaging lens system is f, the distance from the image-side surface of the eighth lens to the imaging surface on the optical axis is BL, and the distance from the object-side surface of the first lens to the image-side surface of the eighth lens on the optical axis is TD. These conditions must be met: 18.7 ≤ Vmin < 20.0; 0.97 ≤ TL / f ≤ 1.05; and 0.07 ≤ BL / TD < 0.

18.

11. The imaging lens system according to claim 1, characterized in that, The Abbe number of the first lens is V1, the Abbe number of the second lens is V2, the Abbe number of the third lens is V3, the Abbe number of the fourth lens is V4, the Abbe number of the fifth lens is V5, the Abbe number of the sixth lens is V6, the Abbe number of the seventh lens is V7, the Abbe number of the eighth lens is V8, and the Abbe number of the i-th lens is Vi, which satisfies the following condition: 150.0 < ΣVi < 320.0, where i = 1, 2, 3, 4, 5, 6, 7, 8.

12. The imaging lens system according to claim 1, characterized in that, The Abbe number of the first lens is V1, the Abbe number of the second lens is V2, the Abbe number of the third lens is V3, the Abbe number of the fourth lens is V4, the Abbe number of the fifth lens is V5, the Abbe number of the sixth lens is V6, the Abbe number of the seventh lens is V7, the Abbe number of the eighth lens is V8, and the Abbe number of the i-th lens is Vi. The refractive index of the first lens is N1, the refractive index of the second lens is N2, the refractive index of the third lens is N3, the refractive index of the fourth lens is N4, the refractive index of the fifth lens is N5, the refractive index of the sixth lens is N6, the refractive index of the seventh lens is N7, the refractive index of the eighth lens is N8, and the refractive index of the i-th lens is Ni. The minimum value of Vi / Ni is (Vi / Ni)min, which satisfies the following condition: 9.5 < (Vi / Ni)min < 11.80, where i = 1, 2, 3, 4, 5, 6, 7, 8.

13. The imaging lens system according to claim 1, characterized in that, The minimum Abbe number of the lens in this imaging lens system is Vmin, which satisfies the following condition: 8.0 < Vmin < 19.0.

Images