Imaging optical lens system, imaging apparatus and electronic device

Abstract

An imaging optical system comprises eight lenses sequentially from the object side to the image side, wherein the eight lenses are, from the object side to the image side, 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 lens has an object-side surface facing the object side and an image-side surface facing the image side. The first lens has negative refractive power. The second lens has negative refractive power. The image-side surface of the second lens is concave near the optical axis. The object-side surface of the fourth lens is concave near the optical axis. The object-side surface of the fifth lens is convex near the optical axis. The sixth lens has negative refractive power. The image-side surface of the eighth lens includes at least one inflection point. High image quality can be provided when certain conditions are met.

Description

Technical Field

[0001] This disclosure relates to an imaging optical system and an image-capturing device, and more particularly to a miniaturized imaging optical system and image-capturing device for use in electronic devices. Prior Technology

[0002] With advancements in semiconductor manufacturing technology, the performance of electronic image sensors has improved, allowing for smaller pixel sizes. Therefore, high-quality optical lenses have become indispensable. As technology advances rapidly, the applications of electronic devices equipped with optical lenses are expanding, leading to more diverse requirements for these lenses. Since traditional optical lenses often struggled to balance requirements such as image quality, manufacturing sensitivity, aperture size, size, and viewing angle, this invention provides a high-quality optical lens to meet these needs. Summary of the Invention

[0003] The imaging optical system, image acquisition device, and electronic device disclosed herein, through the configuration of lens surface shape and refractive power in the imaging optical system, facilitate the adjustment of the optical path and improve imaging quality.

[0004] This disclosure provides an imaging optical system comprising eight lenses sequentially from the object side to the image side, wherein the eight lenses are, from the object side to the image side, 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 lens has an object-side surface facing the object side and an image-side surface facing the image side. Preferably, the first lens has negative refractive power. Preferably, the second lens has negative refractive power. Preferably, the image-side surface of the second lens is concave near the optical axis. Preferably, the object-side surface of the fourth lens is concave near the optical axis. Preferably, the object-side surface of the fifth lens is convex near the optical axis. Preferably, the sixth lens has negative refractive power. Preferably, the image-side surface of the eighth lens includes at least one inflection point. The focal length of the imaging optical system is f, the combined focal length of the seventh and eighth lenses is f78, the radius of curvature of the image-side surface of the first lens is R2, and the radius of curvature of the image-side surface of the second lens is R4. Preferably, it satisfies the following conditions: -1.20 < f / f78 < 0.10; and 0.10 < |R2 / R4| < 10.00.

[0005] According to the present disclosure, an imaging device is provided, comprising the aforementioned imaging optical system and an electronic photosensitive element, wherein the electronic photosensitive element is disposed on an imaging surface of the imaging optical system.

[0006] According to this disclosure, an electronic device is provided, which includes the aforementioned image capturing device.

[0007] This disclosure provides an imaging optical system comprising eight lenses sequentially from the object side to the image side, wherein the eight lenses are, from the object side to the image side, 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 lens has an object-side surface facing the object side and an image-side surface facing the image side. Preferably, the first lens has negative refractive power. Preferably, the second lens has negative refractive power. Preferably, the object-side surface of the fourth lens is concave near the optical axis. Preferably, the sixth lens has negative refractive power. The focal length of the first lens is f1, the focal length of the seventh lens is f7, and the Abbe number of the eighth lens is V8. Preferably, the following conditions are satisfied: 0.00 < |f1 / f7| < 0.60; and 5.0 < V8 < 30.0.

[0008] This disclosure provides an imaging optical system comprising eight lenses sequentially from the object side to the image side, wherein the eight lenses are, from the object side to the image side, 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 lens has an object-side surface facing the object side and an image-side surface facing the image side. Preferably, the first lens has negative refractive power. Preferably, the second lens has negative refractive power. Preferably, the object-side surface of the fourth lens is concave near the optical axis. Preferably, the sixth lens has negative refractive power. Preferably, the image-side surface of the eighth lens includes at least one inflection point. The distance on the optical axis from the object-side surface of the first lens to the image-side surface of the eighth lens is TD, the focal length of the imaging optical system is f, and the combined focal length of the seventh and eighth lenses is f78. Preferably, it satisfies the following conditions: 2.00 < TD / f < 5.00; and -0.80 < f / f78 < 0.00.

[0009] When f / f78 meets the above conditions, it helps to correct spherical aberration and astigmatism, and balance the refractive force distribution at the image side of the imaging optical system, thereby improving image quality.

[0010] When |R2 / R4| meets the above conditions, it helps to adjust the direction of light travel, thereby increasing the viewing angle.

[0011] When |f1 / f7| meets the above conditions, it helps to balance the refractive force distribution of the imaging optical system, thereby improving the imaging quality.

[0012] When V8 meets the above conditions, the Abbe number of the eighth lens can be adjusted to achieve a balance between chromatic aberration and back focal length.

[0013] When TD / f meets the above conditions, it helps to balance the total length and angle of view of the imaging optical system, so as to form a wide-angle characteristic. Simple Explanation of the Diagram

[0014] Figure 1A illustrates a schematic diagram of an image-capturing device according to a first embodiment of the present disclosure; Figure 1B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the first embodiment; Figure 2A illustrates a schematic diagram of an imaging device according to a second embodiment of the present disclosure; Figure 2B shows the spherical aberration, astigmatism, and distortion curves of the second embodiment from left to right; Figure 3A illustrates a schematic diagram of an image-capturing device according to a third embodiment of this disclosure; Figure 3B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the third embodiment; Figure 4A illustrates a schematic diagram of an imaging device according to a fourth embodiment of this disclosure; Figure 4B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the fourth embodiment; Figure 5A illustrates a schematic diagram of an imaging device according to a fifth embodiment of this disclosure; Figure 5B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the fifth embodiment; Figure 6A illustrates a schematic diagram of an imaging device according to a sixth embodiment of this disclosure; Figure 6B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the sixth embodiment; Figure 7A illustrates a schematic diagram of an imaging device according to a seventh embodiment of this disclosure; Figure 7B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the seventh embodiment; Figure 8A illustrates a schematic diagram of an imaging device according to an eighth embodiment of this disclosure; Figure 8B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the eighth embodiment; Figure 9A illustrates a schematic diagram of an imaging device according to a ninth embodiment of this disclosure; Figure 9B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the ninth embodiment; Figure 10A illustrates a schematic diagram of an imaging device according to a tenth embodiment of this disclosure; Figure 10B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the tenth embodiment; Figure 11A illustrates a schematic diagram of an imaging device according to the eleventh embodiment of this disclosure; Figure 11B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the eleventh embodiment; Figure 12A illustrates a schematic diagram of an imaging device according to the twelfth embodiment of this disclosure; Figure 12B, from left to right, shows the spherical aberration, astigmatism, and distortion curves of the twelfth embodiment; Figure 13 illustrates a schematic diagram of the inflection points and critical points of each lens according to the first embodiment; Figure 14 illustrates a perspective view of an imaging device according to the thirteenth embodiment of this disclosure; Figure 15A illustrates a schematic diagram of one side of an electronic device according to the fourteenth embodiment of this disclosure; Figure 15B shows a schematic diagram of the other side of the electronic device as shown in Figure 15A; Figure 15C illustrates a system diagram of the electronic device based on Figure 15A; Figure 16 illustrates a schematic diagram of one side of an electronic device according to the fifteenth embodiment of this disclosure; Figure 17 illustrates a schematic diagram of one side of an electronic device according to the sixteenth embodiment of this disclosure; Figure 18A illustrates a schematic diagram of one side of an electronic device according to the seventeenth embodiment of this disclosure; Figure 18B illustrates a schematic diagram of the other side of the electronic device as shown in Figure 18A; and Figure 19 illustrates a perspective view of an electronic device according to the eighteenth embodiment of this disclosure. Implementation

[0015] This disclosure provides an imaging optical system comprising eight lenses sequentially from the object side to the image side, wherein the eight lenses are, from the object side to the image side, 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 lens has an object-side surface facing the object side and an image-side surface facing the image side.

[0016] The first lens can have negative refractive power, which helps to increase the angle of view.

[0017] The second lens may have negative refractive power, which can be used in conjunction with the third lens to help correct spherical aberration. The image-side surface of the second lens may be concave near the optical axis, which helps correct astigmatism in the imaging optical system to balance the image quality between the center and periphery. The object-side surface of the second lens may contain at least one inflection point, which helps correct off-axis aberration caused by large viewing angles.

[0018] The third lens can have positive refractive power, which helps to reduce the volume of the object-side end of the imaging optics system.

[0019] The object-side surface of the fourth lens is concave near the optical axis, which allows adjustment of the lens's shape and refractive power, helping to mitigate the angular difference between the incident light and the optical axis. The image-side surface of the fourth lens can be convex near the optical axis, which allows adjustment of the light's exit direction from the lens, helping to reduce total internal reflection.

[0020] The fifth lens can have positive refractive power, which helps to share the converging power of the imaging optical system. The object-side surface of the fifth lens near the optical axis can be convex, which can adjust the surface shape of the fifth lens and help to enhance the positive refractive power of the fifth lens.

[0021] The sixth lens can have negative refractive power, which helps to balance the aberrations that arise in the imaging optical system in order to reduce its size.

[0022] The image-side surface of the eighth lens may contain at least one inflection point, which helps to correct image curvature and distortion of the imaging optical system, while shortening the overall length of the imaging optical system.

[0023] Of the eight lenses, the third lens has the greatest thickness along the optical axis, which helps to provide sufficient focusing capability for the imaging optical system.

[0024] At least one of the third, fourth, and fifth lenses may be made of glass, which helps to reduce the degradation of image quality caused by changes in ambient temperature.

[0025] The focal length of the imaging optical system is f, and the combined focal length of the seventh and eighth lenses is f78, which satisfies the following condition: -1.20 < f / f78 < 0.10. This helps to correct spherical aberration and astigmatism, and balances the refractive power distribution at the image end of the imaging optical system, thereby improving image quality. Furthermore, it satisfies the following conditions: -0.80 < f / f78 < 0.00. Furthermore, it satisfies the following conditions: -0.60 < f / f78 < -0.05. Furthermore, it satisfies the following conditions: -0.43 ≤ f / f78 ≤ -0.10.

[0026] The radius of curvature of the image-side surface of the first lens is R2, and the radius of curvature of the image-side surface of the second lens is R4, satisfying the following condition: 0.10 < |R2 / R4| < 10.00. This helps to adjust the direction of light travel, thereby increasing the viewing angle. Furthermore, it satisfies the following conditions: 0.15 < |R2 / R4| < 4.00. Furthermore, it satisfies the following conditions: 0.20 < |R2 / R4| < 2.00. Furthermore, it satisfies the following conditions: 0.30 < |R2 / R4| < 1.00. Furthermore, it satisfies the following condition: 0.53 ≤ |R2 / R4| ≤ 0.69.

[0027] The first lens has a focal length of f1, and the seventh lens has a focal length of f7, satisfying the following condition: 0.00 < |f1 / f7| < 0.60. This helps to balance the refractive power distribution of the imaging optical system, thereby improving image quality. Furthermore, it satisfies the following conditions: 0.00 < |f1 / f7| < 0.40. Furthermore, it satisfies the following conditions: 0.00 < |f1 / f7| < 0.30. Furthermore, it satisfies the following condition: 0.01 ≤ |f1 / f7| ≤ 0.22.

[0028] The Abbe number of the eighth lens is V8, which satisfies the following condition: 5.0 < V8 < 30.0. Therefore, the Abbe number of the eighth lens can be adjusted to achieve a balance between chromatic aberration and back focal length. Furthermore, it satisfies the following condition: 10.0 < V8 < 28.0. Moreover, it satisfies the following condition: 18.2 ≤ V8 ≤ 25.6.

[0029] The distance on the optical axis from the object-side surface of the first lens to the image-side surface of the eighth lens is TD. The focal length of the imaging optical system is f, which satisfies the following condition: 2.00 < TD / f < 5.00. This helps to balance the total length and viewing angle of the imaging optical system, thus facilitating the formation of wide-angle characteristics. Furthermore, it satisfies the following condition: 2.50 < TD / f < 5.00. Furthermore, it satisfies the following condition: 3.00 < TD / f < 4.80. Furthermore, it satisfies the following condition: 3.49 ≤ TD / f ≤ 4.55.

[0030] The maximum field of view (FOV) in an imaging optical system satisfies the following condition: 120.0 degrees < FOV < 190.0 degrees. This helps to give the imaging optical system a larger field of view and increase the image capture range. Furthermore, it can also satisfy the following condition: 125.0 degrees < FOV < 190.0 degrees.

[0031] The distance from the image-side surface of the eighth lens to an imaging plane on the optical axis is BL, and the maximum image height of the imaging optical system is ImgH, which satisfies the following condition: 0.50 < 10×BL / ImgH < 3.00. This helps to shorten the back focal length of the imaging optical system and control the overall length of the imaging optical system. Furthermore, it can satisfy the following condition: 1.00 < 10×BL / ImgH < 2.50.

[0032] The imaging optical system may further include an aperture, the distance from the aperture to the imaging plane on the optical axis being SL, and the distance from the object-side surface of the first lens to the imaging plane on the optical axis being TL, which satisfy the following condition: 0.30 < SL / TL < 0.55. This allows adjustment of the aperture position, helping to control the viewing angle and size of the imaging optical system. Furthermore, it can satisfy the following condition: 0.40 < SL / TL < 0.50.

[0033] The thickness of the first lens along the optical axis is CT1, the thickness of the second lens along the optical axis is CT2, the thickness of the third lens along the optical axis is CT3, the thickness of the fourth lens along the optical axis is CT4, the thickness of the fifth lens along the optical axis is CT5, the thickness of the sixth lens along the optical axis is CT6, the thickness of the seventh lens along the optical axis is CT7, and the thickness of the eighth lens along the optical axis is CT8. The largest of CT1, CT2, CT3, CT4, CT5, CT6, CT7, and CT8 is CTmax. The focal length of the imaging optical system is f, which satisfies the following condition: 0.40 < CTmax / f < 1.20. This helps to control lens forming and reduce manufacturing difficulty. Furthermore, it can also satisfy the following condition: 0.65 < CTmax / f < 1.00.

[0034] The combined focal length of the first, second, and third lenses is f123, and the combined focal length of the fifth, sixth, and seventh lenses is f567, satisfying the condition: 0.60 < f123 / f567 < 8.00. This helps to improve light collection capability over a wider angle and control aberrations. Furthermore, it satisfies the condition: 1.50 < f123 / f567 < 7.00.

[0035] The sixth lens has a focal length of f6, and the eighth lens has a focal length of f8, satisfying the following condition: 0.00 < |f6 / f8| < 2.00. This helps to balance the refractive power distribution of the lens at the image side of the imaging optical system and correct aberrations. Furthermore, it satisfies the following condition: 0.40 < |f6 / f8| < 1.40.

[0036] The distance from the object-side surface of the first lens to the imaging plane along the optical axis is TL, and the maximum image height of the imaging optical system is ImgH, which satisfies the following condition: 2.00 < TL / ImgH < 4.00. This helps to compress the overall length of the imaging optical system while providing a larger light-gathering area. Furthermore, it satisfies the following condition: 2.20 < TL / ImgH < 3.50. Furthermore, it satisfies the following condition: 2.40 < TL / ImgH < 3.00.

[0037] The maximum image height of the imaging optical system is ImgH, and the focal length of the imaging optical system is f, which satisfies the following condition: 1.00 < ImgH / f < 2.00. This helps to control the field of view angle of the imaging optical system. Furthermore, it can satisfy the following condition: 1.15 < ImgH / f < 1.85.

[0038] The distance from the image-side surface of the eighth lens to the imaging plane on the optical axis is BL, and the thickness of the third lens on the optical axis is CT3, which satisfies the following condition: 0.15 < BL / CT3 < 0.70. This helps to control the lens shaping of the third lens. Furthermore, it can satisfy the following condition: 0.20 < BL / CT3 < 0.40.

[0039] The distance on the optical axis from the object-side surface of the second lens to the image-side surface of the third lens is Dr3r6, and the distance on the optical axis from the object-side surface of the fifth lens to the image-side surface of the sixth lens is Dr9r12, satisfying the following condition: 1.60 < Dr3r6 / Dr9r12 < 3.00. This allows for adjustment of the lens configuration of the imaging optical system, helping to improve assembly yield. Furthermore, it satisfies the following condition: 2.00 < Dr3r6 / Dr9r12 < 2.80.

[0040] The optical axis spacing between the first and second lenses is T12, and the optical axis spacing between the sixth and seventh lenses is T67, satisfying the condition: 0.50 < T12 / T67 < 4.00. This helps to balance the spatial configuration at both the object and image sides of the imaging optical system and gives the imaging optical system a large viewing angle. Furthermore, it satisfies the condition: 0.80 < T12 / T67 < 2.50.

[0041] The distance from the image-side surface of the eighth lens to the imaging plane on the optical axis is BL, and the focal length of the imaging optical system is f, which satisfies the following condition: 1.50 < 10 × BL / f < 4.00. This helps to shorten the back focal length, thereby reducing the overall length of the imaging optical system. Furthermore, it can satisfy the following condition: 2.00 < 10 × BL / f < 3.50.

[0042] The second lens has a focal length of f2, and the fourth lens has a focal length of f4, satisfying the following condition: 0.00 < |f2 / f4| < 1.60. This helps to balance the refractive power distribution of the lens at the object side of the imaging optical system and correct aberrations. Furthermore, it satisfies the following condition: 0.25 < |f2 / f4| < 1.40.

[0043] In an imaging optical system, the total thickness of all lenses along the optical axis is ΣCT, and the total distance between any two adjacent lenses along the optical axis is ΣAT. This satisfies the following condition: 1.20 < ΣCT / ΣAT < 2.50. This helps improve space utilization efficiency. Furthermore, it also satisfies the following condition: 1.40 < ΣCT / ΣAT < 2.40.

[0044] The distance from the object-side surface of the first lens to the aperture on the optical axis is Dr1rs, and the focal length of the imaging optical system is f, which satisfies the following condition: 1.50 < Dr1rs / f < 3.50. This balances the volume of the object-side end of the imaging optical system with the overall refractive power of the system, helping to increase the viewing angle. Furthermore, it satisfies the following condition: 1.70 < Dr1rs / f < 3.00.

[0045] The sixth lens has an Abbe number of V6, which satisfies the following condition: 5.0 < V6 < 26.0. Therefore, the material of the sixth lens can be adjusted to correct chromatic aberration. Furthermore, it satisfies the following condition: 10.0 < V6 < 26.0.

[0046] The various technical features in the imaging optical system disclosed above can be combined and configured to achieve the corresponding effects.

[0047] In the imaging optical system disclosed herein, the lens can be made of glass or plastic. If the lens is made of glass, the freedom in configuring the refractive power of the imaging optical system is increased, and glass lenses can be manufactured using techniques such as grinding or molding. If the lens is made of plastic, production costs can be effectively reduced. Furthermore, spherical or aspherical (ASP) surfaces can be incorporated into the lens. Spherical lenses reduce manufacturing difficulty, while aspherical surfaces provide more controllable variables to reduce aberrations, decrease the number of lenses, and effectively reduce the overall length of the imaging optical system disclosed herein. Aspherical surfaces can be manufactured using methods such as plastic injection molding or molding glass lenses.

[0048] In the imaging optical system disclosed herein, additives can be selectively added to any (or more) lens materials to produce light absorption or interference effects, thereby altering the transmittance of the lens for specific wavelengths of light and reducing stray light and color shift. For example, the additives may filter out light in the 600nm-800nm ​​wavelength range to reduce excess red or infrared light; or they may filter out light in the 350nm-450nm wavelength range to reduce 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. Additionally, the additives can also be deposited on the lens surface to provide the aforementioned effects.

[0049] In the imaging optical system disclosed herein, if the lens surface is aspherical, it means that the entire or a portion of the optically effective area of ​​the lens surface is aspherical.

[0050] In the imaging optical system provided in this disclosure, if the lens surface is convex and the location of the convex surface is not defined, it means that the lens surface can be convex near the optical axis; if the lens surface is concave and the location of the concave surface is not defined, it means that the lens surface can be concave near the optical axis. In the imaging optical system provided in this disclosure, if the lens has positive or negative refractive power, or the focal length of the lens, it can refer to the refractive power or focal length of the lens near the optical axis.

[0051] In the imaging optical system disclosed herein, the critical point is the point on the lens surface that is tangent to a plane perpendicular to the optical axis, in addition to the point where it intersects with the optical axis; the inflection point is the point where the positive and negative curvature of the lens surface intersects.

[0052] The imaging surface of the imaging optical system disclosed herein can be a plane or a curved surface with any curvature, depending on the corresponding electronic photosensitive element, particularly a curved surface with a concave surface facing the object side. Furthermore, in the imaging optical system of this disclosure, one or more imaging correction elements (such as planar elements) can be selectively arranged between the lens closest to the imaging surface and the imaging surface in the imaging optical path to achieve the effect of correcting image curvature (e.g., image warping). The optical properties of the imaging correction element, such as curvature, thickness, refractive index, position, and surface shape (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 facing the object side near the imaging surface.

[0053] In addition, the imaging optical system disclosed herein can be equipped with at least one aperture stop, such as an aperture stop, glare stop, or field stop, as needed, which helps to reduce stray light and improve image quality.

[0054] In the imaging optical system disclosed herein, the aperture configuration can be a front aperture or a center aperture. A front aperture means that the aperture is set between the subject and the first lens, while a center aperture means that the aperture is set between the first lens and the imaging plane. If the aperture is a front aperture, it can create a longer distance between the exit pupil of the imaging optical system and the imaging plane, giving it a telecentric effect and increasing the efficiency of image reception by the CCD or CMOS sensor. If the aperture is a center aperture, it helps to expand the field of view of the imaging optical system, giving it the advantages of a wide-angle lens.

[0055] This disclosure may appropriately incorporate a variable aperture element, which can be a mechanical component or a light control element, capable of electrically or by electrical signals controlling the size and shape of the aperture. The mechanical component may include movable parts such as blade assemblies or shielding plates; the light control element may include masking materials such as filter elements, electrochromic materials, or liquid crystal layers. The variable aperture element can enhance image adjustment capabilities by controlling the amount of light entering the image or the exposure time. Furthermore, the variable aperture element can also be the aperture of this disclosure, allowing for adjustment of image quality, such as depth of field or exposure speed, by changing the aperture value.

[0056] This disclosure allows for the appropriate placement of one or more optical elements to restrict the form of light passing through the imaging optical system. These optical elements may be filters, polarizers, etc., but are not limited to these components. Furthermore, the optical elements may be monolithic elements, composite components, or thin films, but are not limited to these methods. The optical elements can be placed between the object end, image end, or lenses of the imaging optical system to control the passage of specific forms of light, thereby meeting application requirements.

[0057] The imaging optical system disclosed herein may include at least one optical lens, optical element, or carrier, at least one surface of which has a low-reflection layer. This low-reflection layer effectively reduces stray light generated by reflection at the interface. The low-reflection layer may be disposed in a non-effective area of ​​the object-side or image-side surface of the optical lens, or on the connecting surface between the object-side and image-side surfaces. The optical element may be a light-shielding element, an annular spacer element, a lens barrel element, a cover glass, blue glass, a filter (color filter), a light path deflection element, a prism, or a mirror, etc. The carrier may be a lens mount, a microlens disposed on the photosensitive element, the periphery of the photosensitive element substrate, or a glass sheet used to protect the photosensitive element, etc.

[0058] The imaging optical system disclosed herein can also be applied in various electronic devices such as three-dimensional (3D) image capture, digital cameras, mobile products, digital tablets, smart TVs, network monitoring equipment, motion-sensing game consoles, dashcams, reversing cameras, wearable products, and drones.

[0059] This disclosure provides an image-capturing device comprising an imaging optical system as described above and an electronic photosensitive element, wherein the electronic photosensitive element is disposed on the imaging surface of the imaging optical system. The arrangement of the lens surface shape within the imaging optical system facilitates a balance between optical path adjustment and the size of the imaging optical system, providing high image quality while maintaining its miniaturization. Preferably, the image-capturing device may further include a lens barrel, a support device, or a combination thereof.

[0060] This disclosure provides an electronic device that includes the aforementioned image capturing device. This improves image quality. Preferably, the aforementioned electronic device may further include a control unit, a display unit, a storage unit, a temporary storage unit, or a combination thereof.

[0061] Based on the above implementation methods, specific embodiments are presented below and described in detail with reference to the accompanying drawings.

[0062] <First Embodiment>

[0063] Please refer to Figures 1A and 1B, where Figure 1A illustrates a schematic diagram of an imaging device 1 according to a first embodiment of this disclosure, and Figure 1B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the first embodiment. As shown in Figure 1A, the imaging device 1 of the first embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, includes, in sequence, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between the eight lenses.

[0064] The first lens E1 has negative refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are spherical.

[0065] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis; both are aspherical. Furthermore, referring to Figure 13, a schematic diagram is shown illustrating the inflection point IP and critical point CP of each lens according to the first embodiment. The object-side surface of the second lens E2 includes an inflection point IP (labeled in Figure 13) and a critical point CP (labeled in Figure 13).

[0066] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are spherical.

[0067] The fourth lens E4 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 includes a curvature point IP (labeled in Figure 13), and the image-side surface of the fourth lens E4 includes a curvature point IP (labeled in Figure 13) and a critical point CP (labeled in Figure 13).

[0068] The fifth lens E5 has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fifth lens E5 includes a curvature point IP (marked in Figure 13).

[0069] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis. Both are aspherical.

[0070] The seventh lens E7 has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both being aspherical. Furthermore, the object-side surface of the seventh lens E7 includes a curvature point IP (labeled in Figure 13) and a critical point CP (labeled in Figure 13), and the image-side surface of the seventh lens E7 also includes a curvature point IP (labeled in Figure 13) and a critical point CP (labeled in Figure 13).

[0071] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis, both of which are aspherical. In addition, the image-side surface of the eighth lens E8 includes a curvature point IP (marked in Figure 13) and a critical point CP (marked in Figure 13).

[0072] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0073] The equations for the aspherical surfaces of the above lenses are expressed as follows: ;in: X: The displacement parallel to the optical axis from the intersection of the aspherical surface and the optical axis to a point on the aspherical surface at a distance Y from the optical axis; Y: The perpendicular distance between a point on the aspherical curve and the optical axis; R: Radius of curvature; k: cone coefficient; and Ai: The i-th order aspherical coefficient.

[0074] In the imaging optical system of the first embodiment, the focal length of the imaging optical system is f, the aperture value (f-number) of the imaging optical system is Fno, and half of the maximum field of view of the imaging optical system is HFOV, with the following values: f = 4.56 mm; Fno = 2.80; and HFOV = 74.6 degrees.

[0075] In the imaging optical system of the first embodiment, the maximum field of view in the imaging optical system is FOV, which satisfies the following condition: FOV = 149.2 degrees.

[0076] In the imaging optical system of the first embodiment, the distance from the object-side surface of the first lens E1 to the imaging surface IMG on the optical axis is TL, and the maximum image height of the imaging optical system is ImgH, which satisfies the following condition: TL / ImgH = 2.85.

[0077] In the imaging optical system of the first embodiment, the distance from the image-side surface of the eighth lens E8 to the imaging plane IMG on the optical axis is BL, and the maximum image height of the imaging optical system is ImgH, which satisfies the following condition: 10×BL / ImgH = 1.77.

[0078] In the imaging optical system of the first embodiment, the distance from the aperture ST to the imaging surface IMG on the optical axis is SL, and the distance from the object-side surface of the first lens E1 to the imaging surface IMG on the optical axis is TL, which satisfies the following condition: SL / TL = 0.44.

[0079] In the imaging optical system of the first embodiment, the thickness of the first lens E1 on the optical axis is CT1, the thickness of the second lens E2 on the optical axis is CT2, the thickness of the third lens E3 on the optical axis is CT3, the thickness of the fourth lens E4 on the optical axis is CT4, the thickness of the fifth lens E5 on the optical axis is CT5, the thickness of the sixth lens E6 on the optical axis is CT6, the thickness of the seventh lens E7 on the optical axis is CT7, and the thickness of the eighth lens E8 on the optical axis is CT8. The largest of CT1, CT2, CT3, CT4, CT5, CT6, CT7, and CT8 is CTmax. The focal length of the imaging optical system is f, which satisfies the following condition: CTmax / f = 0.78.

[0080] In the imaging optical system of the first embodiment, the maximum image height of the imaging optical system is ImgH, and the focal length of the imaging optical system is f, which satisfies the following condition: ImgH / f = 1.34.

[0081] In the imaging optical system of the first embodiment, the distance on the optical axis from the object-side surface of the first lens E1 to the image-side surface of the eighth lens E8 is TD, and the focal length of the imaging optical system is f, which satisfies the following condition: TD / f = 3.59.

[0082] In the imaging optical system of the first embodiment, the distance from the image-side surface of the eighth lens E8 to the imaging plane IMG on the optical axis is BL, and the focal length of the imaging optical system is f, which satisfies the following condition: 10×BL / f = 2.38.

[0083] In the imaging optical system of the first embodiment, the focal length of the first lens E1 is f1, the focal length of the second lens E2 is f2, the focal length of the fourth lens E4 is f4, the focal length of the sixth lens E6 is f6, the focal length of the seventh lens E7 is f7, and the focal length of the eighth lens E8 is f8, which satisfy the following conditions: |f1 / f7| = 0.05; |f2 / f4| = 0.98; and |f6 / f8| = 0.98.

[0084] In the imaging optical system of the first embodiment, the focal length of the imaging optical system is f, and the combined focal length of the seventh lens E7 and the eighth lens E8 is f78, which satisfies the following condition: f / f78 = -0.38.

[0085] In the imaging optical system of the first embodiment, the combined focal length of the first lens E1, the second lens E2 and the third lens E3 is f123, and the combined focal length of the fifth lens E5, the sixth lens E6 and the seventh lens E7 is f567, which satisfies the following condition: f123 / f567 = 3.57.

[0086] In the imaging optical system of the first embodiment, the distance from the object-side surface of the first lens E1 to the aperture ST on the optical axis is Dr1rs, and the focal length of the imaging optical system is f, which satisfies the following condition: Dr1rs / f = 2.15.

[0087] In the imaging optical system of the first embodiment, the total thickness of each lens on the optical axis is ΣCT, and the total distance between any two adjacent lenses on the optical axis is ΣAT, which satisfies the following condition: ΣCT / ΣAT = 2.10.

[0088] In the imaging optical system of the first embodiment, the distance between the first lens E1 and the second lens E2 on the optical axis is T12, and the distance between the sixth lens E6 and the seventh lens E7 on the optical axis is T67, which satisfies the following condition: T12 / T67 = 1.03.

[0089] In the imaging optical system of the first embodiment, the distance from the image-side surface of the eighth lens E8 to the imaging plane IMG on the optical axis is BL, and the thickness of the third lens E3 on the optical axis is CT3, which satisfies the following condition: BL / CT3 = 0.30.

[0090] In the imaging optical system of the first embodiment, the distance on the optical axis from the object-side surface of the second lens E2 to the image-side surface of the third lens E3 is Dr3r6, and the distance on the optical axis from the object-side surface of the fifth lens E5 to the image-side surface of the sixth lens E6 is Dr9r12, which satisfies the following condition: Dr3r6 / Dr9r12 = 2.41.

[0091] In the imaging optical system of the first embodiment, the radius of curvature of the image-side surface of the first lens E1 is R2, and the radius of curvature of the image-side surface of the second lens E2 is R4, which satisfies the following condition: |R2 / R4| = 0.65.

[0092] In the imaging optical system of the first embodiment, the Abbe number of the sixth lens E6 is V6, and the Abbe number of the eighth lens E8 is V8, which satisfy the following conditions: V6 = 19.5; and V8 = 21.3.

[0093] Please also refer to Table 1A and Table 1B below. Table 1A, First Embodiment f (focal length) = 4.56 mm, fno (aperture) = 2.80, HFOV (half angle of view) = 74.6 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 21.3354 SPH 1.994 Glass 1.804 46.5 -6.43 2 3.9907 SPH 1.864 3 Second lens 21.3666 ASP 0.952 plastic 1.669 19.5 -13.13 4 6.1154 ASP 0.144 5 Third lens 4.9649 SPH 3.563 Glass 1.805 25.5 4.80 6 -11.9020 SPH 0.398 7 Fourth lens -3.9675 ASP 0.399 plastic 1.650 21.8 -13.43 8 -7.5644 ASP 0.495 9 aperture flat -0.156 10 Fifth lens 3.1845 ASP 1.114 plastic 1.544 56.0 3.74 11 -4.9226 ASP 0.041 12 Sixth lens -50.2334 ASP 0.777 plastic 1.669 19.5 -10.62 13 8.3243 ASP 1.804 14 Seventh Lens 46.6796 ASP 1.068 plastic 1.544 56.0 129.34 15 137.5606 ASP 0.696 16 Eighth lens -28.6557 ASP 1.231 plastic 1.657 21.3 -10.79 17 9.5744 ASP 0.308 18 Filter element flat 0.210 Glass 1.517 64.2 - 19 flat 0.565 20 Imaging surface flat - The reference wavelength is 587.6 nm (d-line). Table 1B, Aspheric Coefficients surface 3 4 7 8 10 11 k = 3.34498E+01 -3.35433E+00 -1.12545E+01 -2.19289E+01 -6.01470E+00 5.71129E-02 A4 = 4.404151309E-03 9.730228407E-03 4.745594163E-03 1.729014195E-03 4.164787849E-04 -1.079602153E-02 A6 = -8.059004598E-04 -1.027212873E-03 -1.764508197E-03 8.170254839E-04 1.567419787E-03 -1.433375388E-02 A8 = 5.443247413E-05 2.207304363E-04 6.230145548E-04 2.508646124E-05 -4.883888259E-04 8.923990874E-02 A10= 5.910857773E-06 -6.363910582E-05 -3.561634583E-05 1.061293126E-04 -1.521182977E-03 -1.929434137E-01 A12= -5.323309892E-06 7.428942501E-06 1.186374542E-03 2.349895574E-01 A14= 1.033504097E-06 -4.524127963E-07 -3.052910339E-04 -1.789219571E-01 A16= -9.467315825E-08 9.187022186E-08 8.635160990E-02 A18= 4.288817804E-09 -1.461413629E-08 -2.559960641E-02 A20= -7.700470157E-11 7.421229368E-10 4.241624774E-03 A22= -2.999834957E-04 Surface 12 13 14 15 16 17 k = 8.72632E+01 -8.80396E+01 9.43524E+01 8.73546E+01 -9.87776E+01 -1.41480E+01 A4 = -1.119285135E-02 2.137199566E-02 -7.455244967E-03 7.414802463E-03 7.807741768E-03 1.961173459E-02 A6 = 1.881733629E-02 -8.782002530E-03 5.986363165E-03 -9.161485578E-04 -1.246233125E-02 -1.881784567E-02 A8 = -1.575222680E-02 6.729380862E-03 -5.186785722E-03 -7.285739434E-05 5.132167179E-03 8.050058357E-03 A10= 8.200106541E-03 -3.803607054E-03 2.334356007E-03 -2.926981777E-05 -8.710614984E-04 -2.300721838E-03 A12= -2.935036898E-03 1.462733603E-03 -7.172444166E-04 1.447028511E-05 -1.075041238E-04 4.706458196E-04 A14= 6.351136501E-04 -3.740979641E-04 1.553024928E-04 -2.178547868E-06 9.587123636E-05 -7.042724596E-05 A16= -6.044993684E-05 5.711761991E-05 -2.283046576E-05 1.608816203E-07 -2.613223863E-05 7.750513381E-06 A18= -3.892148631E-06 2.108224253E-06 -5.975756784E-09 4.321756582E-06 -6.265771937E-07 A20= -1.074724576E-07 8.888459768E-11 -4.812893170E-07 3.696504297E-08 A22= 2.234495702E-09 3.689693981E-08 -1.568044446E-09 A24= -1.923089333E-09 4.648974080E-11 A26= 6.514047098E-11 -9.134275887E-13 A28= -1.293698878E-12 1.067949638E-14 A30= 1.143417006E-14 -5.622628472E-17

[0094] Table 1A shows the detailed structural data for the first embodiment in Figure 1A, where the units for radius of curvature, thickness, and focal length are mm, and surfaces 0-20 sequentially represent the surfaces from the object side to the image side, with the refractive index measured at the reference wavelength. Table 1B shows the aspherical data for the first embodiment, where k represents the cone coefficient in the aspherical curve equation, and A4-A30 represent the 4th-30th 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 1A and 1B of the first embodiment, and will not be repeated here.

[0095] <Second Embodiment>

[0096] Please refer to Figures 2A and 2B, where Figure 2A illustrates a schematic diagram of an image-capturing device 2 according to the second embodiment of this disclosure, and Figure 2B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the second embodiment. As shown in Figure 2A, the image-capturing device 2 of the second embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, sequentially includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, a sixth lens E6, an aperture stop S1, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between these eight lenses.

[0097] The first lens E1 has negative refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are spherical.

[0098] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point.

[0099] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are spherical.

[0100] The fourth lens E4 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 includes an inflection point, and the image-side surface of the fourth lens E4 includes an inflection point and a critical point.

[0101] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both of these surfaces are aspherical.

[0102] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis. Both are aspherical.

[0103] The seventh lens E7 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis, both of which are aspherical. In addition, the image-side surface of the seventh lens E7 includes an inflection point and a critical point.

[0104] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 includes an inflection point and a critical point, and the image-side surface of the eighth lens E8 also includes an inflection point and a critical point.

[0105] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0106] Please also refer to Table 2A and Table 2B below. Table 2A, Second Embodiment f (focal length) = 4.47 mm, fno (aperture value) = 2.80, HFOV (half angle of view) = 85.1 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 20.6159 SPH 1.806 Glass 1.804 46.5 -6.51 2 4.0101 SPH 1.875 3 Second lens 21.9123 ASP 0.999 plastic 1.661 20.3 -13.91 4 6.3560 ASP 0.148 5 Third lens 5.1547 SPH 3.489 Glass 1.805 25.5 4.97 6 -12.5058 SPH 0.402 7 Fourth lens -4.0261 ASP 0.394 plastic 1.650 21.8 -14.00 8 -7.5019 ASP 0.472 9 aperture flat -0.146 10 Fifth lens 3.1009 ASP 1.114 plastic 1.544 56.0 3.59 11 -4.6090 ASP 0.040 12 Sixth lens -26.5751 ASP 0.760 plastic 1.669 19.5 -10.10 13 9.1695 ASP 0.280 14 Aperture flat 1.577 15 Seventh Lens -43.4783 ASP 1.099 plastic 1.544 56.0 -44.93 16 56.3180 ASP 0.507 17 Eighth lens 36.4447 ASP 1.356 plastic 1.669 19.5 -18.22 18 8.9990 ASP 0.426 19 Filter element flat 0.210 Glass 1.517 64.2 - 20 flat 0.444 twenty one Imaging surface flat - The reference wavelength is 587.6 nm (d-line). The effective radius of surface 14 (aperture S1) is 1.822 mm. Table 2B, Aspheric Coefficient surface 3 4 7 8 10 11 k = 2.69247E+01 -3.67880E+00 -1.15093E+01 -2.08589E+01 -5.82270E+00 2.42949E-01 A4 = 4.742694959E-03 1.001114790E-02 5.218665063E-03 1.477628330E-03 8.819507849E-04 -1.023764302E-02 A6 = -9.148523298E-04 -1.165084869E-03 -2.422556650E-03 7.158927860E-04 1.130779755E-03 -2.596038326E-02 A8 = 1.036647736E-04 2.110224814E-04 9.030250510E-04 1.876093935E-04 5.316721686E-04 1.364711001E-01 A10= -9.682289051E-06 -2.126682208E-05 -7.813012843E-05 8.040392306E-05 -2.606529468E-03 -3.031830693E-01 A12= -1.893812614E-06 -1.527634299E-05 1.746387853E-03 3.945027242E-01 A14 = 4.843829581E-07 5.208353657E-06 -4.262191223E-04 -3.253838622E-01 A16 = -3.577611289E-08 -6.479113462E-07 1.717299905E-01 A18 = 7.157037269E-10 3.437243422E-08 -5.619789553E-02 A20 = 1.387506328E-11 -5.502052652E-10 1.038425748E-02 A22 = -8.282262961E-04 Surface 12 13 15 16 17 18 k = 8.95580E+01 -9.67900E+01 3.68766E+01 9.90000E+01 -9.90000E+01 -9.17757E+00 A4 = -1.093355535E-02 2.010439703E-02 -1.089097853E-02 1.249040531E-03 8.823483115E-03 3.164672600E-02 A6 = 1.902339790E-02 -6.966662620E-03 1.482553002E-02 3.436903520E-03 -1.955808274E-02 -3.047043618E-02 A8 = -1.697085524E-02 5.240289268E-03 -1.452120438E-02 -1.622964088E-03 1.207573494E-02 1.380923464E-02 A10= 9.871636734E-03 -2.995760627E-03 8.111626680E-03 2.992716907E-04 -4.644688481E-03 -4.084325856E-03 A12= -3.837633772E-03 1.220667258E-03 -3.024165341E-03 -2.872459760E-05 1.244794558E-03 8.438177247E-04 A14= 8.409628763E-04 -3.415593339E-04 7.642312093E-04 1.322835853E-06 -2.441128410E-04 -1.253328246E-04 A16= -7.653588442E-05 5.665774639E-05 -1.283209945E-04 -6.101531092E-09 3.548163900E-05 1.356227342E-05 A18= -4.069318745E-06 1.361537925E-05 -1.804323502E-09 -3.812382196E-06 -1.073865196E-06 A20= -8.224179374E-07 4.907776338E-11 3.001016461E-07 6.198821852E-08 A22= 2.147368978E-08 -1.702999752E-08 -2.573424368E-09 A24= 6.765971427E-10 7.470433878E-11 A26= -1.782450964E-11 -1.437520266E-12 A28= 2.791120431E-13 1.645902011E-14 A30= -1.961076387E-15 -8.482219501E-17

[0107] In the second embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions of the parameters in the table below are the same as in the first embodiment, and will not be repeated here.

[0108] By combining Tables 2A and 2B, the data in Table 2C below can be calculated: Table 2C, Second Embodiment f [mm] 4.47 |f2 / f4| 0.99 Fno 2.80 |f6 / f8| 0.55 HFOV [degree] 85.1 f / f78 -0.36 FOV [degree] 170.1 f123 / f567 3.82 TL / ImgH 2.71 Dr1rs / f 2.15 10×BL / ImgH 1.69 ΣCT / ΣAT 2.14 SL / TL 0.44 T12 / T67 1.01 CTmax / f 0.78 BL / CT3 0.31 ImgH / f 1.43 Dr3r6 / Dr9r12 2.42 TD / f 3.62 |R2 / R4| 0.63 10×BL / f 2.42 V6 19.5 |f1 / f7| 0.14 V8 19.5

[0109] <Third Embodiment>

[0110] Please refer to Figures 3A and 3B, where Figure 3A illustrates a schematic diagram of an image-capturing device 3 according to a third embodiment of this disclosure, and Figure 3B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the third embodiment. As shown in Figure 3A, the image-capturing device 3 of the third embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, sequentially includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between these eight lenses.

[0111] The first lens E1 has negative refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are spherical.

[0112] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point.

[0113] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are spherical.

[0114] The fourth lens E4 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 contains a point of inflection, and the image-side surface of the fourth lens E4 contains a point of inflection.

[0115] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis; both are aspherical. In addition, the object-side surface of the fifth lens, E5, contains a point of inflection.

[0116] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the sixth lens, E6, includes an inflection point and a critical point.

[0117] The seventh lens E7 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the seventh lens E7 includes an inflection point and a critical point, and the image-side surface of the seventh lens E7 also includes an inflection point and a critical point.

[0118] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 contains three inflection points and one critical point, and the image-side surface of the eighth lens E8 contains one inflection point and one critical point.

[0119] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0120] Please also refer to Table 3A and Table 3B below. Table 3A, Third Embodiment f (focal length) = 4.35 mm, Fno (aperture value) = 2.80, HFOV (half angle of view) = 74.6 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 20.1393 SPH 1.547 Glass 1.804 46.5 -6.24 2 3.8779 SPH 1.866 3 Second lens 20.9140 ASP 0.986 plastic 1.669 19.5 -17.55 4 7.3775 ASP 0.135 5 Third lens 5.6914 SPH 3.556 Glass 1.805 25.5 5.46 6 -13.8798 SPH 0.419 7 Fourth lens -4.1599 ASP 0.384 plastic 1.642 22.5 -14.75 8 -7.6899 ASP 0.486 9 aperture flat -0.153 10 Fifth lens 3.1771 ASP 1.083 plastic 1.544 56.0 3.99 11 -6.0275 ASP 0.040 12 Sixth lens 22.2028 ASP 0.760 plastic 1.697 16.3 -14.11 13 6.7195 ASP 1.833 14 Seventh Lens 35.0298 ASP 1.091 plastic 1.544 56.0 -552.75 15 31.0307 ASP 0.588 16 Eighth lens 24.3940 ASP 1.319 plastic 1.669 19.5 -14.85 17 6.9061 ASP 0.237 18 Filter element flat 0.210 Glass 1.517 64.2 - 19 flat 0.686 20 Imaging surface flat - The reference wavelength is 587.6 nm (d-line). Table 3B, Aspheric Coefficients surface 3 4 7 8 10 11 k = 3.00165E+01 -4.77345E+00 -1.21814E+01 -1.84208E+01 -5.83918E+00 1.08784E+00 A4 = 4.908906731E-03 9.676551519E-03 4.202808135E-03 1.366975321E-03 8.114757048E-04 -1.398529638E-02 A6 = -2.148829125E-03 -3.091625605E-03 -1.162462365E-03 1.075508481E-03 -1.653038382E-03 -3.969634172E-02 A8 = 1.067607809E-03 2.176902190E-03 4.460637021E-04 6.247210022E-05 8.287152481E-03 2.214416533E-01 A10= -3.812365188E-04 -1.056000144E-03 -1.657874025E-05 5.369891219E-05 -1.064200086E-02 -5.078574038E-01 A12= 8.327342135E-05 3.126471943E-04 5.579043137E-03 6.695310357E-01 A14= -1.149181234E-05 -5.840149603E-05 -1.118823121E-03 -5.493280155E-01 A16= 9.744830355E-07 6.702190717E-06 2.838625930E-01 A18= -4.616847787E-08 -4.289682122E-07 -8.959435611E-02 A20= 9.326773700E-10 1.168287714E-08 1.572708282E-02 A22= -1.172625242E-03 surface 12 13 14 15 16 17 k = -9.88380E+01 -5.46905E+01 -6.90863E+01 4.69554E+01 -9.90000E+01 -1.58292E+01 A4 = -1.564533770E-02 2.250973991E-02 -1.044262525E-02 1.990830121E-03 3.720503839E-03 2.925782360E-02 A6 = 2.239073788E-02 -5.976193361E-03 1.120107108E-02 2.945896708E-03 -9.822448441E-03 -2.907425985E-02 A8 = -1.820517110E-02 2.092110639E-03 -8.407207247E-03

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127] [[ID=20-1.509893672E-03 3.545205005E-03 1.355239856E-02 A10= 8.711737956E-03 -9.490038120E-04 3.362648604E-03 2.938667860E-04 -2.363978580E-04 -4.124373778E-03 A12= -2.634632151E-03 6.297614804E-04 -8.383625092E-04 -3.087623460E-05 -2.411429407E-04 8.757211095E-04 A14= 4.848823247E-04 -2.844771087E-04 1.302545325E-04 1.789864016E-06 1.011978791E-04 -1.332636819E-04 A16= -4.466874700E-05 6.435706561E-05 -1.147174877E-05 -4.875323537E-08 -2.156130272E-05 1.471584242E-05 A18= -5.711859347E-06 3.601853116E-07 1.220603854E-10 2.987589463E-06 -1.184528821E-06 A20= 1.999241006E-08 1.423959694E-11 -2.865786996E-07 6.929194522E-08 A22= -1.437727140E-09 1.926142116E-08 -2.908486594E-09 A24= -8.923695136E-10 8.523892317E-11 A26= 2.717933616E-11 -1.654576316E-12 A28= -4.901585183E-13 1.910386716E-14 A30= 3.967564108E-15 -9.928627379E-17

[0121] In the third embodiment, the equation of the aspherical curve is expressed in the same form as in the first embodiment. Furthermore, the definitions of the parameters in the following table are the same as in the first embodiment, and will not be repeated here.

[0122] By combining Tables 3A and 3B, the data in Table 3C below can be calculated: Table 3C, Third Implementation Example f [mm] 4.35 |f2 / f4| 1.19 Fno 2.80 |f6 / f8| 0.95 HFOV [degrees] 74.6 f / f78 -0.30 FOV [degrees] 149.2 f123 / f567 5.42 TL / ImgH 2.79 Dr1rs / f 2.16 10×BL / ImgH 1.85 ΣCT / ΣAT 2.06 SL / TL 0.45 T12 / T67 1.02 CTmax / f 0.82 BL / CT3 0.32 ImgH / f 1.41 Dr3r6 / Dr9r12 2.48 TD / f 3.67 |R2 / R4| 0.53 10×BL / f 2.61 V6 16.3 |f1 / f7| 0.01 V8 19.5

[0123] <Fourth Embodiment>

[0124] Please refer to Figures 4A and 4B, where Figure 4A illustrates a schematic diagram of an image-capturing device 4 according to the fourth embodiment of this disclosure, and Figure 4B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the fourth embodiment. As shown in Figure 4A, the image-capturing device 4 of the fourth embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, includes, in sequence, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between these eight lenses.

[0125] The first lens E1 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the image-side surface of the first lens E1 contains a point of inflection.

[0126] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point.

[0127] The third lens E3 has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are aspherical.

[0128] The fourth lens E4 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 contains a point of inflection, and the image-side surface of the fourth lens E4 contains a point of inflection.

[0129] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis; both are aspherical. In addition, the object-side surface of the fifth lens, E5, contains a point of inflection.

[0130] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis. Both are aspherical.

[0131] The seventh lens E7 has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the seventh lens E7 includes an inflection point and a critical point, and the image-side surface of the seventh lens E7 also includes an inflection point and a critical point.

[0132] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 includes an inflection point and a critical point, and the image-side surface of the eighth lens E8 also includes an inflection point and a critical point.

[0133] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0134] Please also refer to Table 4A and Table 4B below. Table 4A, Fourth Embodiment f (focal length) = 4.44 mm, fno (aperture) = 2.80, HFOV (half angle of view) = 67.8 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 19.2091 ASP 1.210 plastic 1.535 55.9 -9.02 2 3.7704 ASP 2.624 3 Second lens 20.8407 ASP 0.989 plastic 1.661 20.3 -14.03 4 6.2952 ASP 0.268 5 Third lens 5.3196 ASP 3.458 plastic 1.614 25.6 6.36 6 -11.0023 ASP 0.366 7 Fourth lens -4.2782 ASP 0.398 plastic 1.587 28.3 -17.06 8 -7.7243 ASP 0.465 9 aperture flat -0.129 10 Fifth lens 3.2885 ASP 1.161 plastic 1.544 56.0 3.68 11 -4.4890 ASP 0.086 12 Sixth lens -23.6355 ASP 0.833 plastic 1.669 19.5 -9.52 13 8.8453 ASP 2.012 14 Seventh Lens 35.4312 ASP 1.038 plastic 1.566 37.4 700.80 15 38.4942 ASP 0.588 16 Eighth lens 53.6446 ASP 1.133 plastic 1.661 20.3 -13.87 17 7.7608 ASP 0.457 18 Filter element flat 0.210 Glass 1.517 64.2 - 19 flat 0.453 20 Imaging surface flat - The reference wavelength is 587.6 nm (d-line). Table 4B, Aspheric Coefficient surface 1 2 3 4 5 6 k = 3.46735E+00 -1.43461E-01 2.80817E+01 -3.30227E+00 -1.90758E-01 1.24616E+00 A4 = 5.133879252E-05 -8.819413050E-04 3.681352428E-03 8.970547637E-03 -1.369879330E-04 6.452656385E-04 A6 = 5.967022048E-06 6.652848761E-04 2.526072385E-04 4.344164845E-04 3.368378935E-05 -4.660885337E-04 A8 = -1.099125147E-08 -2.013430425E-04 -4.504405077E-04 -7.739487802E-04 2.711738258E-06 6.545724623E-05 A10= -4.697263256E-09 4.269709875E-05 1.233720785E-04 2.606561207E-04 -3.250218079E-06 5.789175622E-06 A12= -3.098736099E-10 -6.078523628E-06 -1.912064799E-05 -4.366421411E-05 2.784912719E-07 -1.393675720E-06 A14= 1.923788585E-11 5.343744728E-07 1.712228976E-06 1.867986876E-06 A16= -3.458032891E-13 -2.555870338E-08 -8.479502059E-08 4.642054071E-07 A18= 2.152420451E-15 4.896862607E-10 2.057192934E-09 -6.734951903E-08 A20= -1.677429974E-11 2.704720418E-09 surface 7 8 10 11 12 13 k = -1.19749E+01 -1.67664E+01 -6.28027E+00 -3.79283E-01 1.72925E+01 -9.90000E+01 A4 = 6.353302480E-03 1.411541069E-03 1.323463956E-04 -9.058125561E-03 -7.649706324E-03 2.037876690E-02 A6 = -3.510651421E-03 1.320880673E-04 5.748938502E-04 -9.964799884E-03 9.587823194E-03 -8.902796696E-03 A8 = 1.329347411E-03 5.812557888E-04 5.671878521E-04 4.761751453E-02 -6.639116193E-03 6.458097414E-03 A10= -1.293352447E-04 6.286685765E-06 -1.896617896E-03 -9.264523243E-02 3.291103898E-03 -3.445988698E-03 A12= 1.160176545E-03 1.047132987E-01 -1.226300603E-03 1.257011002E-03 A14= -2.652426228E-04 -7.470417181E-02 2.525132127E-04 -3.002177143E-04 A16= 3.383226890E-02 -1.973116231E-05 4.139006494E-05 A18= -9.416644930E-03 -2.448978714E-06 A20= 1.466923655E-03 A22= -9.783467009E-05 Surface 14 15 16 17 k = 9.28754E+01 5.89968E+01 -6.83281E+01 -1.04902E+01 A4 = -4.793928545E-03 6.653356809E-03 8.473246977E-03 3.513383506E-02 A6 = 3.434778734E-03 -6.722976914E-04 -1.784566464E-02 -3.340700782E-02 A8 = -3.483817251E-03 -2.837592677E-06 1.092940079E-02 1.487946556E-02 A10= 1.514899603E-03 -7.743975773E-05 -4.386527825E-03 -4.255094444E-03 A12= -4.015559470E-04 2.556455089E-05 1.314090815E-03 8.421372346E-04 A14= 6.697422366E-05 -3.519262349E-06 -3.043267496E-04 -1.193320381E-04 A16= -6.839055281E-06 2.509614422E-07 5.330094693E-05 1.229430416E-05 A18= 3.822333255E-07 -9.159298163E-09 -6.861831678E-06 -9.253748847E-07 A20= -7.933332211E-09 1.353501154E-10 6.366187572E-07 5.069490616E-08 A22= -8.326472719E-11 -4.180229185E-08 -1.993822616E-09 A24= 1.889992664E-09 5.472999453E-11 A26= -5.590452880E-11 -9.938955605E-13 A28= 9.734798827E-13 1.071703692E-14 A30= -7.565683881E-15 -5.189934337E-17

[0135] In the fourth embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions of the parameters in the table below are the same as in the first embodiment, and will not be repeated here.

[0136] By combining Tables 4A and 4B, the data in Table 4C below can be calculated: Table 4C, Fourth Embodiment f [mm] 4.44 |f2 / f4| 0.82 Fno 2.80 |f6 / f8| 0.69 HFOV [degree] 67.8 f / f78 -0.31 FOV [degree] 135.5 f123 / f567 6.13 TL / ImgH 2.87 Dr1rs / f 2.20 10×BL / ImgH 1.83 ΣCT / ΣAT 1.63 SL / TL 0.45 T12 / T67 1.30 CTmax / f 0.78 BL / CT3 0.32 ImgH / f 1.38 Dr3r6 / Dr9r12 2.27 TD / f 3.72 |R2 / R4| 0.60 10×BL / f 2.52 V6 19.5 |f1 / f7| 0.01 V8 20.3

[0137] <Example 5>

[0138] Please refer to Figures 5A and 5B, where Figure 5A illustrates a schematic diagram of an image-capturing device 5 according to the fifth embodiment of this disclosure, and Figure 5B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the fifth embodiment. As shown in Figure 5A, the image-capturing device 5 of the fifth embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, sequentially includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between the eight lenses.

[0139] The first lens E1 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the first lens E1 includes an inflection point and a critical point.

[0140] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point.

[0141] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are aspherical.

[0142] The fourth lens E4 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 contains a point of inflection, and the image-side surface of the fourth lens E4 contains a point of inflection.

[0143] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both of these surfaces are aspherical.

[0144] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis. Both are aspherical.

[0145] The seventh lens E7 has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the seventh lens E7 includes an inflection point and a critical point, and the image-side surface of the seventh lens E7 also includes an inflection point and a critical point.

[0146] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 includes an inflection point and a critical point, and the image-side surface of the eighth lens E8 also includes an inflection point and a critical point.

[0147] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0148] Please also refer to Table 5A and Table 5B below. Table 5A, Fifth Embodiment f (focal length) = 4.60 mm, fno (aperture) = 2.80, HFOV (half angle of view) = 69.7 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens -76.3359 ASP 1.318 plastic 1.534 56.0 -7.62 2 4.3279 ASP 2.119 3 Second lens 20.5880 ASP 1.052 plastic 1.639 23.5 -14.60 4 6.2906 ASP 0.176 5 Third lens 5.1680 ASP 3.511 Glass 1.755 27.5 5.21 6 -11.6920 ASP 0.416 7 Fourth lens -4.2198 ASP 0.409 plastic 1.669 19.5 -15.48 8 -7.3991 ASP 0.378 9 aperture flat -0.118 10 Fifth lens 3.4044 ASP 1.152 plastic 1.534 56.0 3.89 11 -4.6931 ASP 0.052 12 Sixth lens -27.5594 ASP 0.779 plastic 1.660 20.4 -9.40 13 8.1009 ASP 1.811 14 Seventh Lens 45.2304 ASP 1.187 plastic 1.551 44.5 1444.84 15 47.5050 ASP 0.555 16 Eighth lens 39.8928 ASP 1.364 plastic 1.639 23.5 -13.84 17 7.1375 ASP 0.457 18 Filter element flat 0.210 Glass 1.517 64.2 - 19 flat 0.419 20 Imaging surface flat - The reference wavelength is 587.6 nm (d-line). Table 5B, Aspherical Coefficient surface 1 2 3 4 5 6 k = -9.90000E+01 -2.91177E-01 2.69402E+01 -3.86479E+00 -1.26478E-01 4.70098E-01 A4 = -4.949466807E-05 -1.801432645E-03 2.884251449E-03 7.247776470E-03 2.137689955E-04 1.046459165E-03 A6 = 5.915744487E-05 2.270415287E-03 1.261676714E-03 2.723714188E-03 -6.131671658E-05 -4.599542115E-04 A8 = -9.284748409E-06 -9.571592629E-04 -8.936608621E-04 -2.259634317E-03 -8.298402776E-07 -2.269928551E-05 A10= 8.320532669E-07 2.317007675E-04 2.133746971E-04 7.976465625E-04 -5.119569056E-07 2.835468304E-05 A12= -4.531572663E-08 -2.772297008E-05 -2.624897451E-05 -1.628404788E-04 1.078649772E-07 -2.990362453E-06 A14= 1.547353033E-09 -8.050339789E-07 1.322790196E-06 1.866442290E-05 A16= -3.326843373E-11 7.988398422E-07 3.316545985E-08 -1.004909946E-06 A18= 4.373449604E-13 -1.212264550E-07 -6.273288936E-09 5.164838814E-09 A20= -3.209388029E-15 9.122033776E-09 1.874319675E-10 1.161453423E-09 A22= 1.005843935E-17 -3.542363145E-10 A24 = 5.674094593E-12 surface 7 8 10 11 12 13 k = -1.16696E+01 -1.78337E+01 -6.47180E+00 -6.71578E-01 8.11544E+01 -9.68995E+01 A4 = 6.571060569E-03 1.376511707E-03 -1.324256860E-03 -4.887675361E-03 -7.844466721E-03 2.384071627E-02 A6 = -3.871263805E-03 7.075067380E-05 3.153433458E-03 -9.823232994E-03 1.102132177E-02 -2.010006375E-02 A8 = 1.468355293E-03 6.702088593E-04 -2.999936050E-03 2.610177949E-02 -1.323190921E-02 2.145756649E-02 A10 = -1.428560319E-04 -9.801121096E-06 1.945738551E-03 -3.739377303E-02 1.118959291E-02 -1.576458181E-02 A12= -8.763341318E-04 2.959884484E-02 -5.361624086E-03 7.540093364E-03 A14= 1.481624635E-04 -1.239009081E-02 1.244930027E-03 -2.193622510E-03 A16= 1.820810794E-03 -1.089629971E-04 3.473672812E-04 A18= 4.123753763E-04 -2.281622595E-05 A20= -1.698580032E-04 A22= 1.482927952E-05 Surface 14 15 16 17 k = 3.88481E+01 照原文 3.76845E+01 -1.41369E+01 A4 = -1.657080954E-02 It should be noted that the content of "照原文" at seems incorrect or incomplete. It might need to be further verified or corrected according to the actual situation. -7.100668500E-04 4.788035383E-03 3.103783078E-02 A6 = 2.259648620E-02 7.303095326E-03 -8.885286408E-03 -2.567102372E-02 A8 = -2.010930901E-02 -3.924859146E-03 1.745396975E-03 9.021698995E-03 A10= 9.895583508E-03 9.554104935E-04 1.224216860E-03 -1.905203561E-03 A12= -3.031354047E-03 -1.333628991E-04 -8.469713037E-04 2.636670612E-04 A14= 5.953054624E-04 1.127214679E-05 2.455031989E-04 -2.462796073E-05 A16= -7.461173953E-05 -5.691485998E-07 -4.255468951E-05 1.530231637E-06 A18= 5.718242656E-06 1.575227671E-08 4.860277905E-06 -5.746345536E-08 A20= -2.408126056E-07 -1.834020924E-10 -3.789955425E-07 7.235404748E-10 A22= 4.169571779E-09 2.028080673E-08 4.588906851E-11 A24= -7.298903317E-10 -2.887203720E-12 A26= 1.675386012E-11 7.664665603E-14 A28= -2.185066973E-13 -1.047161041E-15 A30= 1.200251975E-15 6.007723836E-18

[0149] In the fifth embodiment, the equation of the aspherical curve is expressed in the same form as in the first embodiment. Furthermore, the definitions of the parameters in the following table are the same as in the first embodiment, and will not be repeated here.

[0150] By combining Tables 5A and 5B, the data in Table 5C below can be calculated: Table 5C, Fifth Implementation Example f [mm] 4.60 |f2 / f4| 0.94 Fno 2.80 |f6 / f8| 0.68 HFOV [degrees] 69.7 f / f78 -0.33 FOV [degrees] 139.4 f123 / f567 2.64 TL / ImgH 2.83 Dr1rs / f 2.04 10×BL / ImgH 1.78 ΣCT / ΣAT 2.00 SL / TL 0.46 T12 / T67 1.17 CTmax / f 0.76 BL / CT3 0.31 ImgH / f 1.33 Dr3r6 / Dr9r12 2.39 TD / f 3.51 |R2 / R4| 0.69 10×BL / f 2.36 V6 20.4 |f1 / f7| 0.01 V8 23.5

[0151] <Sixth Embodiment>

[0152] Please refer to Figures 6A and 6B, where Figure 6A illustrates a schematic diagram of an image-capturing device 6 according to a sixth embodiment of this disclosure, and Figure 6B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the sixth embodiment. As shown in Figure 6A, the image-capturing device 6 of the sixth embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, includes, in sequence, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between these eight lenses.

[0153] The first lens E1 has negative refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are spherical.

[0154] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point.

[0155] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are spherical.

[0156] The fourth lens E4 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 contains a point of inflection, and the image-side surface of the fourth lens E4 contains a point of inflection.

[0157] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis; both are aspherical. In addition, the object-side surface of the fifth lens, E5, contains a point of inflection.

[0158] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis; both are aspherical. In addition, the image-side surface of the sixth lens, E6, contains a point of inflection.

[0159] The seventh lens E7 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the seventh lens E7 includes an inflection point and a critical point, and the image-side surface of the seventh lens E7 also includes an inflection point and a critical point.

[0160] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 contains one inflection point, and the image-side surface of the eighth lens E8 contains three inflection points and a critical point.

[0161] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0162] Please also refer to Table 6A and Table 6B below. Table 6A, Sixth Embodiment f (focal length) = 4.40 mm, Fno (aperture value) = 2.80, HFOV (half angle of view) = 75.3 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 16.9934 SPH 1.350 Glass 1.804 46.5 -7.04 2 4.0945 SPH 2.126 3 Second lens 25.1812 ASP 0.941 plastic 1.660 20.4 -12.38 4 6.0782 ASP 0.251 5 Third lens 5.3378 SPH 3.570 Glass 1.805 25.5 4.97 6 -11.2240 SPH 0.508 7 Fourth lens -3.3581 ASP 0.382 plastic 1.660 20.4 -16.89 8 -5.0237 ASP 0.495 9 aperture flat -0.098 10 Fifth lens 3.0492 ASP 1.320 plastic 1.544 56.0 3.58 11 -4.5709 ASP 0.040 12 Sixth lens -8.2849 ASP 0.710 plastic 1.660 20.4 -8.44 13 17.6066 ASP 1.305 14 Seventh Lens 95.1552 ASP 1.355 plastic 1.544 56.0 -146.97 15 43.2299 ASP 0.622 16 Eighth lens -199.9998 ASP 1.300 plastic 1.660 20.4 -11.08 17 7.6059 ASP 0.557 18 Filter element flat 0.210 Glass 1.517 64.2 - 19 flat 0.404 20 Imaging surface flat - The reference wavelength is 587.6 nm (d-line). Table 6B, Aspherical Coefficients surface 3 4 7 8 10 11 k = 3.71008E+01 -2.95310E+00 -7.02536E+00 -5.22139E+00 -5.18689E+00 6.49914E-02 A4 = 4.812038821E-03 9.502294554E-03 2.228226842E-03 1.905077324E-03 3.285599852E-03 -1.546672184E-02 A6 = -4.017455692E-04 -1.222052093E-04 -2.202762164E-03 -7.068397057E-04 4.831726843E-04 1.029488346E-02 A8 = -1.149567981E-04 -4.231248446E-04 7.285303197E-04 3.462011125E-04 -1.505346174E-04 -3.008887869E-03 A10= 5.065499705E-05 2.084616054E-04 -5.077801622E-05 1.597663162E-05 -1.122472164E-03 -2.714300263E-03 A12= -1.163858727E-05 -6.188120313E-05 7.184109038E-04 -1.248488995E-04 A14= 1.560666369E-06 1.090554750E-05 -1.741800410E-04 3.603389130E-03 A16= -1.235790576E-07 -1.128007318E-06 -3.386309991E-03 A18= 5.407574518E-09 6.410720286E-08 1.495862780E-03 A20= -1.011060086E-10 -1.552132019E-09 -3.331641380E-04 A22= 2.972703748E-05 surface 12 13 14 15 16 17 k = 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 -2.03014E+01 A4 = -8.097268988E-03 6.170454946E-03 -9.785739343E-03 7.662820161E-03 7.161547338E-03 1.559494447E-02 A6 = 1.273958362E-02 2.633289957E-03 9.664284133E-03 -5.078606088E-03 -1.730368443E-02 -1.763003931E-02 A8 = -6.794201696E-03 7.038864286E-05 -1.511415370E-02 2.392219702E-03 1.026013702E-02 8.061091113E-03 A10= 1.501980701E-03 -3.799282020E-03 1.329057373E-02 -8.255910935E-04 -3.696925786E-03 -2.388104726E-03 A12= -3.314615530E-04 8.078330516E-03 -7.658012221E-03 1.837683627E-04 8.898512435E-04 4.983155570E-04 A14= 1.653923808E-04 -9.342630132E-03 2.964584939E-03 -2.688089529E-05 -1.472063491E-04 -7.570813631E-05 A16= -3.266948145E-05 6.918935240E-03 -7.755261919E-04 2.623717973E-06 1.651182637E-05 8.487248783E-06 A18= -3.516298145E-03 1.357011336E-04 -1.690739220E-07 -1.182849171E-06 -7.041540185E-07 A20= 1.268247106E-03 -1.539082025E-05 6.883365155E-09 4.413100455E-08 4.299691331E-08 A22= -3.278809633E-04 1.057331980E-06 -1.599613913E-10 2.436378566E-10 -1.902698708E-09 A24= 5.993063883E-05 -3.810677725E-08 1.616646684E-12 -1.103600822E-10 5.922684390E-11 A26= -7.389831380E-06 4.940986884E-10 5.133844309E-12 -1.227561709E-12 A28= 5.515095239E-07 -1.052410642E-13 1.518766794E-14 A30= -1.874217100E-08 8.177707037E-16 -8.476384477E-17

[0163] In the sixth embodiment, the equation of the aspherical curve is expressed in the same form as in the first embodiment. Furthermore, the definitions of the parameters in the following table are the same as in the first embodiment, and will not be repeated here.

[0164] By combining Tables 6A and 6B, the data in Table 6C below can be calculated: Table 6C, Implementation Example 6 f [mm] 4.40 |f2 / f4| 0.73 Fno 2.80 |f6 / f8| 0.76 HFOV [degree] 75.3 f / f78 -0.43 FOV [degrees] 150.6 f123 / f567 2.92 TL / ImgH 2.83 Dr1rs / f 2.19 10×BL / ImgH 1.91 ΣCT / ΣAT 2.08 SL / TL 0.45 T12 / T67 1.63 CTmax / f 0.81 BL / CT3 0.33 ImgH / f 1.39 Dr3r6 / Dr9r12 2.30 TD / f 3.68 |R2 / R4| 0.67 10×BL / f 2.66 V6 20.4 |f1 / f7| 0.05 V8 20.4

[0165] <The Seventh Embodiment>

[0166] Please refer to Figures 7A and 7B, where Figure 7A illustrates a schematic diagram of an imaging device 7 according to the seventh embodiment of this disclosure, and Figure 7B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the seventh embodiment. As shown in Figure 7A, the imaging device 7 of the seventh embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, sequentially includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, a sixth lens E6, an aperture stop S1, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between the eight lenses.

[0167] The first lens E1 has negative refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the first lens E1 contains a point of inflection.

[0168] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point.

[0169] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis; both are aspherical. In addition, the image-side surface of the third lens E3 contains a point of inflection.

[0170] The fourth lens E4 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 includes an inflection point, and the image-side surface of the fourth lens E4 includes an inflection point and a critical point.

[0171] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis; both are aspherical. In addition, the object-side surface of the fifth lens, E5, contains a point of inflection.

[0172] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis. Both are aspherical.

[0173] The seventh lens E7 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the seventh lens E7 includes an inflection point and a critical point, and the image-side surface of the seventh lens E7 also includes an inflection point and a critical point.

[0174] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 contains two inflection points and one critical point, and the image-side surface of the eighth lens E8 contains one inflection point and one critical point.

[0175] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0176] Please also refer to Table 7A and Table 7B below. Table 7A, Seventh Embodiment f (focal length) = 4.28 mm, fno (aperture) = 2.60, HFOV (half angle of view) = 84.9 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 20.8771 ASP 1.717 Glass 1.804 46.5 -6.35 2 3.9535 ASP 2.076 3 Second lens 21.1874 ASP 1.001 plastic 1.661 20.3 -14.01 4 6.3214 ASP 0.147 5 Third lens 5.1366 ASP 3.565 Glass 1.805 25.5 4.98 6 -12.5806 ASP 0.399 7 Fourth lens -4.0665 ASP 0.396 plastic 1.650 21.8 -14.04 8 -7.6181 ASP 0.491 9 aperture flat -0.153 10 Fifth lens 3.2205 ASP 1.163 plastic 1.544 56.0 3.69 11 -4.6478 ASP 0.040 12 Sixth lens -29.3719 ASP 0.750 plastic 1.669 19.5 -10.24 13 9.0244 ASP 0.300 14 Aperture flat 1.422 15 Seventh Lens 45.4553 ASP 1.064 plastic 1.567 37.4 -120.39 16 27.0456 ASP 0.616 17 Eighth lens 19.6078 ASP 1.300 plastic 1.669 19.5 -16.07 18 6.7581 ASP 0.806 19 Filter element flat 0.210 Glass 1.517 64.2 - 20 flat 0.151 twenty one Imaging surface flat - The reference wavelength is 587.6 nm (d-line). The effective radius of surface 14 (aperture S1) is 1.922 mm. Table 7B, Aspherical Coefficients surface 1 2 3 4 5 6 k = 1.35900E+00 -3.29420E-02 3.29200E+01 -3.77180E+00 -1.11894E-02 -3.73507E-01 A4 = -8.290265432E-05 -7.442658987E-04 2.792239179E-03 7.626301530E-03 -2.461362575E-05 5.401879679E-04 A6 = 1.395539348E-05 5.137727889E-04 1.297930355E-03 2.037592254E-03 9.884452158E-05 -2.207620681E-04 A8 = -7.292050723E-07 -9.991808009E-05 -9.973946070E-04 -1.904521966E-03 -3.234726517E-05 -4.661359271E-06 A10= 1.655387339E-08 8.695969907E-06 2.910082897E-04 7.497287062E-04 3.689664479E-06 5.905414398E-06 A12= -1.393625603E-10 -2.965994228E-07 -5.231746653E-05 -1.832737522E-04 -1.516526412E-07 1.183359418E-07 A14= 5.957113062E-06 2.798492658E-05 A16= -4.208968128E-07 -2.573134297E-06 A18= 1.695826176E-08 1.304740404E-07 A20= -2.986142825E-10 -2.800242799E-09 Surface 7 8 10 11 12 13 k = -1.16267E+01 -2.04503E+01 -6.26086E+00 9.10885E-02 8.95654E+01 -9.90000E+01 A4 = 5.423412013E-03 1.596694343E-03 2.019392370E-04 -1.389993096E-02 -1.444800829E-02 1.946727596E-02 A6 = -2.513167676E-03 5.511408795E-04 5.429252665E-04 -8.649404344E-03 2.428088542E-02 -9.097855085E-03 A8 = 8.291808337E-04 1.966814066E-04 1.385469763E-03 7.286674801E-02 -2.157347275E-02 8.137793228E-03 A10= -4.978101141E-05 7.392921472E-05 -3.040736643E-03 -1.510275635E-01 1.238428050E-02 -5.318825184E-03 A12= 1.723815979E-03 1.703447106E-01 -4.543919578E-03 2.329312668E-03 A14 = -3.664781719E-04 -1.187923468E-01 9.230594683E-04 -6.390415441E-04 A16 = 5.232913379E-02 -7.859001883E-05 9.692136323E-05 A18 = -1.418647949E-02 -6.127011848E-06 A20 = 2.163231963E-03 A22 = -1.424477494E-04 Surface 15 16 17 18 k = 9.88818E+01 4.03142E+01 -9.90000E+01 -1.23404E+01 A4 = -5.769544683E-03 4.309043143E-03 1.732762448E-03 2.349165186E-02 A6 = 6.961369175E-03 2.727290991E-03 -6.861161279E-03 -2.201123296E-02 A8 = -6.340701593E-03 -1.961557110E-03 2.673279983E-03 9.679997598E-03 A10= 2.604155227E-03 4.618772768E-04 -4.555629070E-04 -2.885084520E-03 A12= -6.207385248E-04 -5.736806365E-05 3.101201975E-05 6.186497259E-04 A14= 8.738940449E-05 3.986229480E-06 -8.813902283E-06 -9.657784919E-05 A16= -6.652709174E-06 -1.449640066E-07 4.609892691E-06 1.097815989E-05 A18= 1.488924959E-07 2.038292588E-09 -1.087162617E-06 -9.067216876E-07 A20= 1.367686612E-08 5.196270607E-12 1.443548491E-07 5.410368294E-08 A22= -8.078343700E-10 -1.198292184E-08 -2.301258008E-09 A24= 6.399322189E-10 6.790651156E-11 A26= -2.149040914E-11 -1.319376895E-12 A28= 4.147813140E-13 1.516633554E-14 A30= -3.520085521E-15 -7.809286179E-17

[0177] In the seventh embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions of the parameters in the table below are the same as in the first embodiment, and will not be repeated here.

[0178] By referring to Tables 7A and 7B, the data in Table 7C below can be calculated: Table 7C, Seventh Embodiment f [mm] 4.28 |f2 / f4| 1.00 Fno 2.60 |f6 / f8| 0.64 HFOV [degree] 84.9 f / f78 -0.30 FOV [degree] 169.9 f123 / f567 3.58 TL / ImgH 2.74 Dr1rs / f 2.29 10×BL / ImgH 1.83 ΣCT / ΣAT 2.05 SL / TL 0.44 T12 / T67 1.21 CTmax / f 0.83 BL / CT3 0.33 ImgH / f 1.49 Dr3r6 / Dr9r12 2.41 TD / f 3.81 |R2 / R4| 0.63 10×BL / f 2.73 V6 19.5 |f1 / f7| 0.05 V8 19.5

[0179] <Eighth Implementation Example>

[0180] Please refer to Figures 8A and 8B, where Figure 8A is a schematic diagram of an imaging device 8 according to the eighth embodiment of this disclosure, and Figure 8B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the eighth embodiment. As can be seen from Figure 8A, the imaging device 8 of the eighth embodiment includes an imaging optical system (not otherwise labeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, sequentially includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. An electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between the eight lenses.

[0181] The first lens E1 has negative refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis. Both are aspherical.

[0182] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point.

[0183] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are aspherical.

[0184] The fourth lens E4 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 includes an inflection point, and the image-side surface of the fourth lens E4 includes an inflection point and a critical point.

[0185] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis; both are aspherical. In addition, the object-side surface of the fifth lens, E5, contains a point of inflection.

[0186] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis; both are aspherical. In addition, the image-side surface of the sixth lens, E6, contains a point of inflection.

[0187] The seventh lens E7 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the seventh lens E7 includes an inflection point and a critical point, and the image-side surface of the seventh lens E7 also includes an inflection point and a critical point.

[0188] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 contains two inflection points and one critical point, and the image-side surface of the eighth lens E8 contains one inflection point and one critical point.

[0189] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0190] Please also refer to Table 8A and Table 8B below. Table 8A, Eighth Embodiment f (focal length) = 4.21 mm, fno (aperture value) = 2.80, HFOV (half angle of view) = 86.5 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 18.1246 ASP 1.417 Glass 1.803 46.8 -6.19 2 3.7629 ASP 2.182 3 Second lens 21.3411 ASP 0.962 plastic 1.661 20.3 -13.32 4 6.1193 ASP 0.153 5 Third lens 5.0747 ASP 3.565 Glass 1.805 25.5 4.85 6 -11.6732 ASP 0.400 7 Fourth lens -3.9699 ASP 0.401 plastic 1.642 22.5 -13.12 8 -7.8082 ASP 0.494 9 aperture flat -0.148 10 Fifth lens 3.1558 ASP 1.114 plastic 1.544 56.0 3.59 11 -4.4728 ASP 0.041 12 Sixth lens -24.3794 ASP 0.760 plastic 1.669 19.5 -9.63 13 8.8653 ASP 1.752 14 Seventh Lens 58.5488 ASP 1.060 plastic 1.544 56.0 -182.53 15 36.5974 ASP 0.653 16 Eighth lens 86.1332 ASP 1.261 plastic 1.656 21.3 -15.57 17 9.0812 ASP 0.457 18 Filter element flat 0.210 Glass 1.517 64.2 - 19 flat 0.459 20 Imaging surface flat - The reference wavelength is 587.6 nm (d-line). Table 8B, Aspheric Coefficient surface 1 2 3 4 5 6 k = 1.70661E-01 -2.89938E-02 3.37109E+01 -3.62260E+00 9.03828E-03 -1.54924E+00 A4 = 1.855128935E-05 -5.306235519E-04 3.143186626E-03 8.135971318E-03 -2.127298510E-04 5.488822290E-04 A6 = -1.260591274E-08 3.792371659E-04 9.090837418E-04 1.372403176E-03 1.589273722E-04 -2.132271991E-04 A8 = -1.726153281E-08 -7.927765703E-05 -8.533829669E-04 -1.507307839E-03 -3.464753314E-05 -5.870254945E-06 A10= 5.575603402E-10 7.160156271E-06 2.652884347E-04 6.346801621E-04 2.768450576E-06 1.244799761E-05 A12= -5.574282351E-12 -2.497855310E-07 -5.005577752E-05 -1.661163241E-04 -6.349929192E-08 -1.173251904E-06 A14 = 5.861059988E-06 2.681601478E-05 A16 = -4.148056819E-07 -2.557556495E-06 A18 = 1.624162055E-08 1.311106559E-07 A20 = -2.695311051E-10 -2.740615437E-09 Surface 7 8 10 11 12 13 k = -1.11783E+01 -2.22115E+01 -5.98414E+00 2.83528E-01 8.32646E+01 -9.90000E+01 A4 = 5.310667296E-03 1.946138845E-03 1.253595192E-03 -1.148138351E-02 -1.248194568E-02 2.055903564E-02 A6 = -2.823502429E-03 1.103417937E-04 -2.691002986E-04 -1.692517341E-02 2.095730192E-02 -8.157770189E-03 A8 = 1.097327259E-03 5.573211143E-04 2.312270592E-03 1.049545105E-01 -1.958545983E-02 6.058559093E-03 A10= -1.036069848E-04 1.117364059E-05 -4.163460868E-03 -2.350183786E-01 1.253602748E-02 -3.272195051E-03 A12= 2.454063016E-03 2.991791735E-01 -5.476207357E-03 1.242851348E-03 A14= -5.644672232E-04 -2.379356407E-01 1.353722210E-03 -3.325326907E-04 A16= 1.195083934E-01 -1.387260348E-04 5.529789340E-05 A18= -3.671716788E-02 -4.149834300E-06 A20= 6.275192383E-03 A22= -4.550086594E-04 Surface 14 15 16 17 k = 9.90000E+01 8.20517E+01 9.90000E+01 -1.03250E+01 A4 = -4.608493312E-03 5.746981231E-03 3.071619234E-03 2.289021018E-02 A6 = 4.578243020E-03 9.346960101E-04 -8.578527232E-03 -2.086852857E-02 A8 = -5.276205152E-03 -1.225291616E-03 3.838418358E-03 8.686216194E-03 A10= 2.723834497E-03 3.252036837E-04 -8.109608761E-04 -2.374008287E-03 A12= -8.857297501E-04 -4.626569830E-05 1.341497944E-05 4.566413536E-04 A14= 1.902677638E-04 3.948862841E-06 3.808061014E-05 -6.366599177E-05 A16= -2.674687990E-05 -2.013687167E-07 -1.120076956E-05 6.516553894E-06 A18= 2.328868347E-06 5.633395376E-09 1.786411533E-06 -4.911282996E-07 A20= -1.112242650E-07 -6.669088698E-11 -1.857150530E-07 2.710269394E-08 A22= 2.131825267E-09 1.312166070E-08 -1.078181791E-09 A24= -6.272008841E-10 3.000415113E-11 A26= 1.946199420E-11 -5.527385245E-13 A28= -3.544255328E-13 6.040981914E-15 A30= 2.878719168E-15 -2.958652799E-17

[0191] In the eighth embodiment, the equation for the aspherical curve is expressed as in the first embodiment. Furthermore, the definitions of the parameters in the table below are the same as in the first embodiment, and will not be repeated here.

[0192] By referring to Tables 8A and 8B, the data in Table 8C below can be calculated: Table 8C, Eighth Embodiment f [mm] 4.21 |f2 / f4| 1.02 Fno 2.80 |f6 / f8| 0.62 HFOV [degree] 86.5 f / f78 -0.29 FOV [degree] 173.1 f123 / f567 3.27 TL / ImgH 2.70 Dr1rs / f 2.27 10×BL / ImgH 1.77 ΣCT / ΣAT 1.91 SL / TL 0.44 T12 / T67 1.25 CTmax / f 0.85 BL / CT3 0.32 ImgH / f 1.51 Dr3r6 / Dr9r12 2.44 TD / f 3.82 |R2 / R4| 0.61 10×BL / f 2.67 V6 19.5 |f1 / f7| 0.03 V8 21.3

[0193] <Ninth Embodiment>

[0194] Please refer to Figures 9A and 9B, where Figure 9A illustrates a schematic diagram of an imaging device 9 according to the ninth embodiment of this disclosure, and Figure 9B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the ninth embodiment. As shown in Figure 9A, the imaging device 9 of the ninth embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, includes, in sequence, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between these eight lenses.

[0195] The first lens E1 has negative refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are spherical.

[0196] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point.

[0197] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are spherical.

[0198] The fourth lens E4 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 includes an inflection point, and the image-side surface of the fourth lens E4 includes an inflection point and a critical point.

[0199] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis; both are aspherical. In addition, the object-side surface of the fifth lens, E5, contains a point of inflection.

[0200] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis; both are aspherical. In addition, the image-side surface of the sixth lens, E6, contains a point of inflection.

[0201] The seventh lens E7 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the image-side surface of the seventh lens E7 contains two inflection points and two critical points.

[0202] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 contains an inflection point, and the image-side surface of the eighth lens E8 contains an inflection point and a critical point.

[0203] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0204] Please also refer to Table 9A and Table 9B below. Table 9A, Ninth Embodiment f (focal length) = 4.35 mm, fno (aperture) = 2.80, HFOV (half angle of view) = 83.5 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 15.9723 SPH 1.492 Glass 1.794 45.4 -6.45 2 3.7200 SPH 2.191 3 Second lens 21.2817 ASP 0.992 plastic 1.669 19.5 -14.21 4 6.4477 ASP 0.142 5 Third lens 5.2103 SPH 3.521 Glass 1.805 25.5 5.01 6 -12.4431 SPH 0.413 7 Fourth lens -3.8585 ASP 0.394 plastic 1.639 23.5 -14.03 8 -7.0463 ASP 0.475 9 aperture flat -0.139 10 Fifth lens 3.1567 ASP 1.211 plastic 1.544 56.0 3.55 11 -4.2973 ASP 0.040 12 Sixth lens -21.6676 ASP 0.760 plastic 1.669 19.5 -9.93 13 9.7125 ASP 1.880 14 Seventh Lens -18.6068 ASP 1.139 plastic 1.551 44.5 -43.52 15 -84.5895 ASP 0.483 16 Eighth lens -108.6782 ASP 1.258 plastic 1.680 18.2 -15.94 17 12.0944 ASP 0.715 18 Filter element flat 0.210 Glass 1.517 64.2 - 19 flat 0.090 20 Imaging surface flat - The reference wavelength is 587.6 nm (d-line). Table 9B, Aspheric Coefficients surface 3 4 7 8 10 11 k = 3.41026E+01 -4.02178E+00 -1.09941E+01 -2.05317E+01 -5.92786E+00 4.58240E-02 A4 = 4.286796982E-03 9.622584010E-03 4.438383181E-03 1.328759819E-03 8.097854649E-04 -1.298010884E-02 A6 = -5.541713949E-04 -9.528724442E-04 -1.821970429E-03 9.668048748E-04 7.293347761E-04 -1.503434938E-02 A8 = -1.203203691E-04 2.317301909E-06 7.563008077E-04 1.258417749E-04 1.599423682E-03 9.463084061E-02 A10= 7.830345034E-05 9.866081356E-05 -6.488594581E-05 7.978835170E-05 -3.873410864E-03 -1.992301020E-01 A12= -2.283774119E-05 -5.397238512E-05 2.414104408E-03 2.375646222E-01 A14= 3.574956788E-06 1.288542282E-05 -5.623920465E-04 -1.782917511E-01 A16= -3.132033611E-07 -1.590707429E-06 8.528844326E-02 A18= 1.455110821E-08 1.001327566E-07 -2.517444109E-02 A20 = -2.798131300E-10 -2.534215912E-09 4.169046021E-03 A22 = -2.959163729E-04 Surface 12 13 14 15 16 17 k = 9.52897E+01 -9.90000E+01 7.54679E+00 [[ID=3同]] -9.90000E+01 9.90000E+01 -7.73743E+00 A4 = -1.291429231E-02 1.710470489E-02 -9.239328941E-03 1.835731282E-03 1.215159508E-02 3.106490682E-02 A6 = 2.014416584E-02 -5.119228383E-03 8.367376605E-03 1.075369627E-03 -2.505080114E-02 -2.995202003E-02 A8 = -1.532208200E-02 4.107518341E-03 -6.755890993E-03 It should be noted that there seems to be a duplicate entry for "" and "" in the original text. I have translated it as is while keeping the duplicate for consistency with the original. If this is an error in the original, it may need to be corrected in the source material.-2.546694291E-04 1.790615363E-02 1.352028992E-02 A10= 6.689775905E-03 -2.445532580E-03 2.857829068E-03 -7.993497496E-05 -8.446705196E-03 -3.948787141E-03 A12= -1.874318499E-03 9.681754809E-04 -7.532988505E-04 3.315825592E-05 2.821364544E-03 7.969052770E-04 A14= 3.124405485E-04 -2.509512757E-04 1.244474444E-04 -4.928580342E-06 -6.796680779E-04 -1.147182854E-04 A16= -2.424309238E-05 3.836684610E-05 -1.210285719E-05 3.778804067E-07 1.185885914E-04 1.198793497E-05 A18= -2.598184902E-06 5.370578161E-07 -1.492737970E-08 -1.500461154E-05 -9.164040998E-07 A20= 5.175755246E-09 2.400848223E-10 1.372701823E-06 5.115444114E-08 A22= -1.003241378E-09 -8.976823275E-08 -2.058414747E-09 A24= 4.088418360E-09 5.804407663E-11 A26= -1.231270524E-10 -1.086610983E-12 A28= 2.203145699E-12 1.211058825E-14 A30= -1.772799041E-14 -6.072393820E-17

[0205] In the ninth embodiment, the equation of the aspherical curve is expressed in the same form as in the first embodiment. Furthermore, the definitions of the parameters in the following table are the same as in the first embodiment, and will not be repeated here.

[0206] By combining Tables 9A and 9B, the data in Table 9C below can be calculated: Table 9C, Ninth Implementation Example f [mm] 4.35 |f2 / f4| 1.01 Fno 2.80 |f6 / f8| 0.62 HFOV [degrees] 83.5 f / f78 -0.39 FOV [degrees] 166.9 f123 / f567 3.46 TL / ImgH 2.71 Dr1rs / f 2.21 10×BL / ImgH 1.59 ΣCT / ΣAT 1.96 SL / TL 0.44 T12 / T67 1.17 CTmax / f 0.81 BL / CT3 0.29 ImgH / f 1.47 Dr3r6 / Dr9r12 2.31 TD / f 3.74 |R2 / R4| 0.58 10×BL / f 2.33 V6 19.5 |f1 / f7| 0.15 V8 18.2

[0207] <Tenth Embodiment>

[0208] Please refer to Figures 10A and 10B, where Figure 10A illustrates a schematic diagram of an imaging device 10 according to the tenth embodiment of this disclosure, and Figure 10B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the tenth embodiment. As shown in Figure 10A, the imaging device 10 of the tenth embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, sequentially includes a first lens E1, a second lens E2, an aperture stop S1, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, an aperture stop S2, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between the eight lenses.

[0209] The first lens E1 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis. Both are aspherical.

[0210] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point.

[0211] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are aspherical.

[0212] The fourth lens E4 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 contains a point of inflection, and the image-side surface of the fourth lens E4 contains a point of inflection.

[0213] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both of these surfaces are aspherical.

[0214] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the image-side surface of the sixth lens, E6, contains two inflection points.

[0215] The seventh lens E7 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis, both of which are aspherical. In addition, the image-side surface of the seventh lens E7 includes an inflection point and a critical point.

[0216] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 contains three inflection points, and the image-side surface of the eighth lens E8 contains one inflection point and one critical point.

[0217] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0218] Please also refer to Table 10A and Table 10B below. Table 10A, Tenth Embodiment f (focal length) = 4.57 mm, fno (aperture value) = 2.80, HFOV (half angle of view) = 76.0 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 54.1830 ASP 1.211 plastic 1.535 55.9 -7.60 2 3.7503 ASP 2.032 3 Second lens 20.3078 ASP 1.032 plastic 1.661 20.3 -14.48 4 6.3693 ASP 0.750 5 Aperture flat -0.516 6 Third lens 5.3246 ASP 3.404 Glass 1.755 27.5 5.29 7 -11.5769 ASP 0.380 8 Fourth lens -4.8515 ASP 0.430 plastic 1.639 23.5 -19.17 9 -8.3153 ASP 0.280 10 aperture flat -0.030 11 Fifth lens 4.2430 ASP 1.174 plastic 1.535 55.9 4.04 12 -3.9643 ASP -0.095 13 Aperture flat 0.190 14 Sixth lens -5.7829 ASP 0.760 plastic 1.669 19.5 -14.46 15 -15.1269 ASP 1.979 16 Seventh Lens -29.0605 ASP 1.163 plastic 1.584 28.2 -37.73 17 92.5926 ASP 0.655 18 Eighth lens -142.8571 ASP 1.163 plastic 1.639 23.5 -16.28 19 11.2457 ASP 0.457 20 Filter element flat 0.210 Glass 1.517 64.2 - twenty one flat 0.397 twenty three Imaging surface flat - The reference wavelength is 587.6 nm (d-line). The effective radius of surface 5 (aperture S1) is 2.681 mm. The effective radius of surface 13 (aperture S2) is 1.313 mm. Table 10B, Aspheric Coefficients surface 1 2 3 4 6 7 k = 4.34642E+01 -2.63167E-01 2.49852E+01 -4.26450E+00 -8.74759E-02 -3.37657E-01 A4 = 1.538987618E-04 -3.113080208E-03 1.668261270E-03 6.514210351E-03 -4.978576411E-05 3.094842465E-03 A6 = 3.630935494E-06 2.374781926E-03 2.976822136E-03 5.067665446E-03 7.271009150E-05 -1.850363582E-03 A8 = -2.529856921E-07 -8.039824275E-04 -1.995955486E-03 -4.562824815E-03 -4.078005647E-05 2.230970248E-04 A10= 1.887666342E-08 1.730896668E-04 6.166021422E-04 1.990759491E-03 5.504927924E-06 4.977027976E-05 A12= -1.106313598E-09 -2.458607428E-05 -1.153628568E-04 -5.294898338E-04 -2.036739135E-07 -1.066330279E-05 A14= 3.300528200E-11 2.236907607E-06 1.344425180E-05 8.726040645E-05 A16= -4.706997852E-13 -1.159915444E-07 -9.579584201E-07 -8.657138247E-06 A18= 2.623785000E-15 2.554020091E-09 3.840462142E-08 4.724919260E-07 A20 = -6.667806106E-10 -1.086472439E-08 surface 8 9 11 12 14 15 k = -1.08804E+01 -2.62530E+01 -7.20159E+00 6.41309E-01 3.54518E+00 6.09436E+01 A4 = 1.256231775E-02 3.927044415E-03 -3.028846917E-03 -7.435951781E-05 6.692195380E-04 1.201814146E-02 A6 = -1.275009205E-02 -6.714381773E-03 1.835464360E-03 -8.867115464E-02 -6.444834405E-03 -1.063362568E-02 A8 = 5.690406197E-03 5.676452948E-03 -1.250262952E-03 3.676809304E-01 1.645059472E-02 1.965509425E-02 A10 = -8.361600062E-04 -9.645406797E-04 2.594868545E-03 -9.304287903E-01 -1.746049307E-02 -2.001616636E-02 A12 = -1.670119086E-03 1.520612043E+00 9.789228551E-03 1.223193668E-02 A14 = 2.764245448E-04 -1.626395493E+00 -3.069502741E-03 -4.395127104E-03 A16 = 1.127234145E+00 3.790125266E-04 8.477052871E-04 A18 = -4.870537448E-01 -6.722554439E-05 A20 = 1.190822421E-01 A22 = -1.257160381E-02 surface 16 17 18 19 k = 7.50517E+01 -9.70695E+01 -4.36230E+01 -8.89264E+00 A4 = -9.833408229E-03 5.610496860E-03 1.093170503E-02 5.096974851E-02 A6 = 1.812339914E-02 1.861514813E-03 -2.095402371E-02 -4.344794282E-02 A8 = -2.102258006E-02 -1.682528386E-03 9.493691430E-03 1.671161774E-02 A10= 1.283062744E-02 4.285594734E-04 -1.312853391E-03 -3.849485416E-03 A12= -4.880455982E-03 -5.912719171E-05 -4.472475462E-04 5.702721685E-04 A14= 1.203108501E-03 4.901348431E-06 2.507449167E-04 -5.502944570E-05 A16= -1.925092148E-04 -2.443000596E-07 -5.884975283E-05 3.262584104E-06 A18= 1.930460213E-05 6.741121009E-09 8.603024274E-06 -8.417788210E-08 A20= -1.102815889E-06 -7.920856928E-11 -8.570290255E-07 -3.274001000E-09 A22= 2.739475663E-08 5.953489551E-08 4.085854125E-10 A24= -2.850782301E-09 -1.826436678E-11 A26= 8.989498755E-11 4.514497985E-13 A28= -1.681525959E-12 -6.101009812E-15 A30= 1.413568451E-14 3.536536063E-17

[0219] In the tenth embodiment, the equation of the aspherical curve is expressed in the same form as in the first embodiment. Furthermore, the definitions of the parameters in the following table are the same as in the first embodiment, and will not be repeated here.

[0220] By combining Tables 10A and 10B, the data in Table 10C below can be calculated: Table 10C, Tenth Implementation Example f [mm] 4.57 |f2 / f4| 0.76 Fno 2.80 |f6 / f8| 0.89 HFOV [degrees] 76.0 f / f78 -0.42 FOV [degrees] 151.9 f123 / f567 2.82 TL / ImgH 2.68 Dr1rs / f 1.97 10×BL / ImgH 1.67 ΣCT / ΣAT 1.84 SL / TL 0.47 T12 / T67 1.03 CTmax / f 0.74 BL / CT3 0.31 ImgH / f 1.39 Dr3r6 / Dr9r12 2.30 TD / f 3.49 |R2 / R4| 0.59 10×BL / f 2.33 V6 19.5 |f1 / f7| 0.20 V8 23.5

[0221] <The Eleventh Embodiment>

[0222] Please refer to Figures 11A and 11B, where Figure 11A illustrates a schematic diagram of an imaging device 11 according to the eleventh embodiment of this disclosure, and Figure 11B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the eleventh embodiment. As shown in Figure 11A, the imaging device 11 of the eleventh embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, sequentially includes a first lens E1, a second lens E2, an aperture stop S1, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, an aperture stop S2, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between the eight lenses.

[0223] The first lens E1 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the image-side surface of the first lens E1 contains two inflection points.

[0224] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point, and the image-side surface of the second lens E2 includes an inflection point.

[0225] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are aspherical.

[0226] The fourth lens E4 has positive refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 contains a point of inflection, and the image-side surface of the fourth lens E4 contains a point of inflection.

[0227] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis; both are aspherical. In addition, the object-side surface of the fifth lens, E5, contains a point of inflection.

[0228] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the image-side surface of the sixth lens, E6, includes an inflection point and a critical point.

[0229] The seventh lens E7 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis, both of which are aspherical. In addition, the image-side surface of the seventh lens E7 includes an inflection point and a critical point.

[0230] The eighth lens E8 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 includes an inflection point and a critical point, and the image-side surface of the eighth lens E8 also includes an inflection point and a critical point.

[0231] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0232] Please also refer to Table 11A and Table 11B below. Table 11A, Eleventh Embodiment f (focal length) = 3.69 mm, fno (aperture) = 2.40, HFOV (half angle of view) = 66.2 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 46.2514 ASP 1.212 plastic 1.544 56.0 -7.07 2 3.5182 ASP 3.039 3 Second lens 18.8183 ASP 1.032 plastic 1.669 19.5 -12.92 4 5.7934 ASP 0.930 5 Aperture flat -0.678 6 Third lens 5.0544 ASP 3.417 Glass 1.785 26.1 5.45 7 -19.5648 ASP 0.431 8 Fourth lens -4.9010 ASP 0.463 plastic 1.544 56.0 36.91 9 -4.0706 ASP 0.208 10 aperture flat 0.114 11 Fifth lens 6.5164 ASP 1.301 plastic 1.544 56.0 4.09 12 -3.1392 ASP -0.184 13 Aperture flat 0.320 14 Sixth lens -4.2549 ASP 0.763 plastic 1.669 19.5 -8.44 15 -18.4863 ASP 1.432 16 Seventh Lens -83.5733 ASP 1.038 plastic 1.587 28.3 -45.31 17 39.2118 ASP 0.452 18 Eighth lens 34.4531 ASP 1.276 plastic 1.614 25.6 -31.03 19 12.0918 ASP 0.457 20 Filter element flat 0.210 Glass 1.517 64.2 - twenty one flat 0.434 twenty three Imaging surface flat - The reference wavelength is 587.6 nm (d-line). The effective radius of surface 5 (aperture S1) is 2.870 mm. The effective radius of surface 13 (aperture S2) is 1.510 mm. Table 11B, Aspheric Coefficients surface 1 2 3 4 6 7 k = 3.20227E+01 -3.06656E-01 2.32004E+01 -4.01075E+00 -3.23137E-01 -2.60641E+01 A4 = 6.517785463E-04 -2.437133585E-03 3.297064095E-03 8.853358557E-03 -1.750248831E-04 2.167978947E-03 A6 = -4.987995618E-05 1.738824002E-03 3.304562630E-04 4.693656217E-04 1.510457027E-04 -4.850994304E-04 A8 = 5.310939651E-06 -5.804727960E-04 -4.225380952E-04 -7.311632106E-04 -6.659374278E-05 -8.332671979E-05 A10= -2.927336080E-07 1.241802797E-04 1.226400458E-04 2.392003126E-04 7.347678958E-06 -5.244431420E-08 A12= 8.791257939E-09 -1.618723546E-05 -2.156633320E-05 -4.720729507E-05 -2.706969854E-07 3.516541180E-06 A14= -1.495225088E-10 1.280260587E-06 2.335421801E-06 5.180889798E-06 A16= 1.358174726E-12 -5.629762431E-08 -1.537114235E-07 -2.263785360E-07 A18= -5.129404615E-15 1.030279665E-09 5.741973365E-09 -3.890324273E-09 A20 = -9.462586618E-11 4.251248510E-10 surface 8 9 11 12 14 15 k = -1.30741E+01 -2.14722E+01 1.68056E+00 4.07437E-01 1.42642E+00 4.12208E+01 A4 = 8.277438460E-03 -4.420358319E-03 1.332058460E-02 -7.215084781E-03 -1.125589592E-02 4.779050428E-03 A6 = -4.401412025E-03 3.709271433E-03 -1.517056762E-02 -5.337065816E-02 1.165395720E-02 3.075704816E-03 A8 = 1.506705967E-03 -3.723738579E-04 1.194879273E-02 1.910726715E-01 3.546707334E-03 -4.371196597E-04 A10= -1.588752978E-04 1.677426257E-04 -8.269897371E-03 -3.501545459E-01 -8.309618741E-03 3.721201090E-04 A12= 3.235005510E-03 4.000591371E-01 4.281046505E-03 -4.169520484E-04 A14= -6.548065346E-04 -2.981649756E-01 -1.091891078E-03 1.725678718E-04 A16= 1.440680196E-01 1.182499883E-04 -3.147705892E-05 A18= -4.341450885E-02 2.177638912E-06 A20= 7.400993976E-03 A22= -5.442976848E-04 Surface 16 17 18 19 k = -9.90000E+01 8.63058E+00 4.39004E+01 -6.94266E+00 A4 = -1.566817817E-02 3.329712078E-03 1.795382945E-02 6.810689366E-02 A6 = 2.293452590E-02 2.029109077E-03 -3.439242477E-02 -6.381752288E-02 A8 = -2.342958451E-02 -1.042113554E-03 2.213313433E-02 3.024562399E-02 A10= 1.343435318E-02 1.283166543E-04 -8.442087913E-03 -9.309488221E-03 A12= -4.974999760E-03 2.679647938E-06 2.170547383E-03 1.991998228E-03 A14= 1.216724358E-03 -2.049592937E-06 -4.028115132E-04 -3.056648816E-04 A16= -1.939818918E-04 1.986558820E-07 5.551178597E-05 3.412656235E-05 A18= 1.922388782E-05 -8.287158342E-09 -5.698733777E-06 -2.785564181E-06 A20= -1.067371573E-06 1.319002219E-10 4.310615972E-07 1.656488191E-07 A22= 2.524932803E-08 -2.353315820E-08 -7.081297263E-09 A24= 8.969844924E-10 2.116317690E-10 A26= -2.255879899E-11 -4.192668215E-12 A28= 3.354668803E-13 4.943133918E-14 A30= -2.229837129E-15 -2.623925360E-16

[0233] In the eleventh embodiment, the equation of the aspherical curve is expressed in the same form as in the first embodiment. Furthermore, the definitions of the parameters in the following table are the same as in the first embodiment, and will not be repeated here.

[0234] By combining Tables 11A and 11B, the data in Table 11C below can be calculated: Table 11C, Eleventh Implementation Example f [mm] 3.69 |f2 / f4| 0.35 Fno 2.40 |f6 / f8| 0.27 HFOV [degrees] 66.2 f / f78 -0.21 FOV [degrees] 132.3 f123 / f567 2.91 TL / ImgH 2.88 Dr1rs / f 2.72 10×BL / ImgH 1.80 ΣCT / ΣAT 1.73 SL / TL 0.43 T12 / T67 2.12 CTmax / f 0.93 BL / CT3 0.32 ImgH / f 1.66 Dr3r6 / Dr9r12 2.14 TD / f 4.49 |R2 / R4| 0.61 10×BL / f [[ID=8​​​​​​​​​​​​​​

[0235] <Twelfth Embodiment>

[0236] Please refer to Figures 12A and 12B, where Figure 12A illustrates a schematic diagram of an image-capturing device 12 according to the twelfth embodiment of this disclosure, and Figure 12B shows, from left to right, the spherical aberration, astigmatism, and distortion curves of the twelfth embodiment. As shown in Figure 12A, the image-capturing device 12 of the twelfth embodiment includes an imaging optical system (unlabeled) and an electronic photosensitive element IS. The imaging optical system, from the object side to the image side of the optical path, sequentially includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture ST, a fifth lens E5, an aperture stop S1, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter element E9, and an imaging surface IMG. The electronic photosensitive element IS is disposed on the imaging surface IMG of the imaging optical system. The imaging optical system includes eight lenses (E1, E2, E3, E4, E5, E6, E7, E8), and there are no other interposed lenses between these eight lenses.

[0237] The first lens E1 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the first lens E1 contains two inflection points, and the image-side surface of the first lens E1 also contains two inflection points.

[0238] The second lens E2 has negative refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the second lens E2 includes an inflection point and a critical point, and the image-side surface of the second lens E2 includes an inflection point.

[0239] The third lens E3 has positive refractive power and is made of glass. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis. Both are aspherical.

[0240] The fourth lens E4 has positive refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the object-side surface of the fourth lens E4 contains two inflection points, and the image-side surface of the fourth lens E4 contains one inflection point.

[0241] The fifth lens, E5, has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is also convex near the optical axis; both are aspherical. In addition, the object-side surface of the fifth lens, E5, contains a point of inflection.

[0242] The sixth lens, E6, has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is convex near the optical axis, both of which are aspherical. In addition, the image-side surface of the sixth lens, E6, includes an inflection point and a critical point.

[0243] The seventh lens E7 has negative refractive power and is made of plastic. Its object-side surface is concave near the optical axis, and its image-side surface is also concave near the optical axis, both of which are aspherical. In addition, the image-side surface of the seventh lens E7 includes an inflection point and a critical point.

[0244] The eighth lens E8 has positive refractive power and is made of plastic. Its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis, both of which are aspherical. In addition, the object-side surface of the eighth lens E8 includes an inflection point and a critical point, and the image-side surface of the eighth lens E8 also includes an inflection point and a critical point.

[0245] The filter element E9 is made of glass and is located between the eighth lens E8 and the imaging surface IMG without affecting the focal length of the imaging optical system.

[0246] Please also refer to Table 12A and Table 12B below. Table 12A, Twelfth Embodiment f (focal length) = 3.61 mm, fno (aperture value) = 2.80, HFOV (half angle of view) = 67.7 degrees surface radius of curvature thickness Material Refractive index Abbe number focal length 0 Subject unlimited unlimited 1 First lens 46.2763 ASP 1.258 plastic 1.535 55.9 -7.02 2 3.4370 ASP 2.963 3 Second lens 18.8752 ASP 1.080 plastic 1.669 19.5 -13.30 4 5.9083 ASP 0.183 5 Third lens 4.9521 ASP 3.443 Glass 1.785 25.8 5.57 6 -25.7629 ASP 0.456 7 Fourth lens -4.7695 ASP 0.491 plastic 1.544 56.0 33.23 8 -3.9108 ASP 0.263 9 aperture flat 0.019 10 Fifth lens 6.0434 ASP 1.175 plastic 1.544 56.0 3.90 11 -3.0491 ASP -0.084 12 Aperture flat 0.300 13 Sixth lens -4.1666 ASP 0.820 plastic 1.669 19.5 -7.75 14 -22.9238 ASP 1.361 15 Seventh Lens -50.2835 ASP 0.942 plastic 1.587 28.3 -32.29 16 30.6493 ASP 0.342 17 Eighth lens 26.6171 ASP 1.410 plastic 1.660 20.4 242.5 18 31.2547 ASP 0.457 19 Filter element flat 0.210 Glass 1.517 64.2 - 20 flat 0.430 twenty one Imaging surface flat - The reference wavelength is 587.6 nm (d-line). The effective radius of surface 12 (aperture S1) is 1.436 mm. Table 12B, Aspheric Coefficient surface 1 2 3 4 5 6 k = 2.96505E+01 -3.29105E-01 2.35530E+01 -4.10280E+00 -2.25821E-01 -3.08367E+01 A4 = 6.043566116E-04 -4.334552880E-03 2.136948854E-03 7.868413118E-03 -2.273784410E-04 2.367342738E-03 A6 = -2.703938570E-05 2.705810198E-03 1.721602254E-03 1.898370144E-03 1.205792087E-04 -5.008972253E-04 A8 = 2.614236468E-06 -8.653651808E-04 -9.861259609E-04 -1.528604536E-03 -2.318285941E-05 -2.440242776E-04 A10= -1.417748021E-07 1.857623045E-04 2.376286446E-04 4.469185318E-04 -1.230585922E-06 6.612445815E-05 A12= 4.230510851E-09 -2.518059573E-05 -3.493861247E-05 -7.047835541E-05 2.376355391E-07 -3.434690963E-06 A14= -7.324414747E-11 2.062269082E-06 3.229028960E-06 4.777310858E-06 A16= 6.882461023E-13 -9.228638134E-08 -1.843443329E-07 1.570193226E-07 A18= -2.697932555E-15 1.701375328E-09 6.044178807E-09 -4.123954381E-08 A20 = -8.893790202E-11 1.648149166E-09 Surface 7 8 10 11 13 14 k = -1.22087E+01 -2.29274E+01 -9.43357E-02 8.33614E-01 1.62985E+00 3.88908E+01 A4 = 8.241935476E-03 -5.146241114E-03 1.821508556E-02 -7.926833548E-03 -7.759692288E-03 3.886877992E-03 A6 = -5.362044163E-03 5.563262141E-03 -2.429609071E-02 -3.831917187E-02 1.166597851E-02 2.005303524E-03 A8 = 2.241820099E-03 -7.221186457E-04 2.323030919E-02 1.701500985E-01 2.284212731E-03 3.107572072E-03 A10= -3.344510447E-04 1.681143970E-04 -2.203626402E-02 -3.937094467E-01 -1.071436814E-02 -3.100998434E-03 A12= 1.207291110E-02 5.654133800E-01 8.104429306E-03 1.422927954E-03 A14= -3.217429767E-03 -5.304023670E-01 -3.092663685E-03 -3.779003631E-04 A16= 3.239051123E-01 4.687087275E-04 5.419345514E-05 A18= -1.242700344E-01 -3.182159739E-06 A20= 2.720477384E-02 A22= -2.592832682E-03 Surface 15 16 17 18 k = -9.88375E+01 -8.12275E+01 3.62678E+01 2.38578E+01 A4 = -1.066493138E-02 9.314747967E-03 2.692292998E-02 1.066728335E-01 A6 = 1.782100271E-02 -4.399737408E-03 -5.792487422E-02 -1.057638841E-01 A8 = -2.861969221E-02 1.691557814E-03 4.530380592E-02 5.436441896E-02 A10= 2.231514745E-02 -5.216786372E-04 -2.108988888E-02 -1.792747575E-02 A12= -1.060997119E-02 9.632015453E-05 6.544451873E-03 4.063465420E-03 A14= 3.211899142E-03 -1.040422523E-05 -1.428950098E-03 -6.556713205E-04 A16= -6.201890260E-04 6.504839648E-07 2.251093734E-04 7.669598980E-05 A18= 7.373775275E-05 -2.188139787E-08 -2.582767805E-05 -6.551501803E-06 A20= -4.912384019E-06 3.066525903E-10 2.155440653E-06 4.078915708E-07 A22= 1.403728583E-07 -1.292745680E-07 -1.827919610E-08 A24= 5.424051866E-09 5.736762692E-10 A26= -1.510781090E-10 -1.195800835E-11 A28= 2.509552769E-12 1.486345604E-13 A30= -1.881915820E-14 -8.334494032E-16

[0247] In the twelfth embodiment, the equation of the aspherical curve is expressed in the same form as in the first embodiment. Furthermore, the definitions of the parameters in the following table are the same as in the first embodiment, and will not be repeated here.

[0248] By combining Tables 12A and 12B, the data in Table 12C below can be calculated: Table 12C, Twelfth Implementation Example f [mm] 3.61 |f2 / f4| 0.40 Fno 2.80 |f6 / f8| 0.03 HFOV [degrees] 67.7 f / f78 -0.10 FOV [degrees] 135.4 f123 / f567 4.18 TL / ImgH 2.86 Dr1rs / f 2.81 10×BL / ImgH 1.79 ΣCT / ΣAT 1.83 SL / TL 0.42 T12 / T67 2.18 CTmax / f 0.95 BL / CT3 0.32 ImgH / f 1.70 Dr3r6 / Dr9r12 2.13 TD / f 4.55 |R2 / R4| 0.58 10×BL / f 3.04 V6 19.5 |f1 / f7| 0.22 V8 20.4

[0249] <Example 13>

[0250] Please refer to Figure 14, which illustrates a perspective view of an image capturing device 100 according to the thirteenth embodiment of this disclosure. As shown in Figure 14, the image capturing device 100 of the thirteenth embodiment is a camera module. The image capturing device 100 includes an imaging lens 101, a driving device assembly 102, and an electronic image sensor 103. The imaging lens 101 includes the imaging optical system of this disclosure and a lens barrel (not otherwise labeled) carrying the imaging optical system. The image capturing device 100 uses the imaging lens 101 to focus light and capture an image of the subject, and coordinates with the driving device assembly 102 to focus the image. Finally, the image is imaged on the electronic image sensor 103, and the image data is output.

[0251] The drive unit assembly 102 can be an autofocus module, and its drive method can be a voice coil motor, microelectromechanical system, piezoelectric system, or shape memory metal drive system. The drive unit assembly 102 enables the imaging optical system to achieve a better imaging position, and can provide clear images of the subject at different object distances.

[0252] The imaging device 100 can be equipped with a high-sensitivity and low-noise electronic image sensor 103 (such as CMOS or CCD) located on the imaging surface of the imaging optical system, which can truly present the good imaging quality of the imaging optical system. In addition, the imaging device 100 may also include an image stabilization module 104, which can be a kinetic energy sensing element such as an accelerometer, gyroscope, or Hall effect sensor. In the thirteenth embodiment, the image stabilization module 104 is a gyroscope, but it is not limited thereto. By adjusting the changes in different axes of the imaging optical system to compensate for the blurry image caused by shaking at the moment of shooting, the imaging quality of shooting in dynamic and low-light scenes is further improved, and advanced image compensation functions such as optical image stabilization (OIS) and electronic image stabilization (EIS) are provided.

[0253] <Fourteenth Embodiment>

[0254] Please refer to Figures 15A, 15B, and 15C, where Figure 15A shows a schematic diagram of one side of an electronic device 200 according to the fourteenth embodiment of this disclosure, Figure 15B shows a schematic diagram of the other side of the electronic device 200 according to Figure 15A, and Figure 15C shows a system schematic diagram of the electronic device 200 according to Figure 15A. As can be seen from Figures 15A, 15B, and 15C, the electronic device 200 of the fourteenth embodiment is a smartphone. The electronic device 200 includes image capturing devices 100, 110, 120, 130, and 140, a flash module 201, a focus assist module 202, an image signal processor (ISP), a user interface 204, and an image software processor 205, wherein the image capturing devices 120, 130, and 140 are front-facing cameras. When a user takes a picture of the subject 206 through the user interface 204, the electronic device 200 uses the image capturing devices 100, 110, 120, 130, and 140 to capture the image, activates the flash module 201 for supplemental lighting, and uses the subject distance information provided by the focus assist module 202 for fast focusing. In addition, the image signal processor 203 and the image software processor 205 perform image optimization processing to further improve the image quality produced by the image lens. The focus assist module 202 can use an infrared or laser focus assist system to achieve fast focusing. The user interface 204 can use a touch screen or a physical shooting button, combined with the diverse functions of the image processing software for image shooting and image processing.

[0255] At least one of the image-capturing devices 100, 110, 120, 130, and 140 in the fourteenth embodiment may include the imaging optical system disclosed herein, and may have the same or similar structure as the image-capturing device 100 in the thirteenth embodiment, which will not be described again here. Specifically, the image-capturing devices 100 and 110 in the fourteenth embodiment may be a wide-angle image-capturing device and an ultra-wide-angle image-capturing device, or a wide-angle image-capturing device and a telephoto image-capturing device, respectively. The image-capturing devices 120, 130, and 140 may be a wide-angle image-capturing device, an ultra-wide-angle image-capturing device, and a TOF module (Time-Of-Flight); however, this configuration is not a limitation. Furthermore, the connection relationships between the image-capturing devices 110, 120, 130, and 140 and other components may be the same as those of the image-capturing device 100 shown in Figure 15C, or may be adapted according to the type of image-capturing device, which will not be shown or described in detail here.

[0256] <Fifteenth Embodiment>

[0257] Please refer to Figure 16, which shows a schematic diagram of one side of an electronic device 300 according to the fifteenth embodiment of this disclosure. The electronic device 300 of the fifteenth embodiment is a smartphone, and the electronic device 300 includes image capturing devices 310, 320, and 330 and a flash module 301.

[0258] The electronic device 300 of the fifteenth embodiment may include the same or similar elements as those in the fourteenth embodiment, and the connection relationships between the image capturing devices 310, 320, and 330 and other elements may also be the same or similar as those disclosed in the fourteenth embodiment, which will not be repeated here. The image capturing devices 310, 320, and 330 in the fifteenth embodiment may all include the imaging optical system disclosed herein, and may all have the same or similar structure as the image capturing device 100 in the thirteenth embodiment, which will not be repeated here. Specifically, the image capturing device 310 may be an ultra-wide-angle image capturing device, the image capturing device 320 may be a wide-angle image capturing device, and the image capturing device 330 may be a telescopic image capturing device (which may include an optical path reversing element), or may be other types of image capturing devices, and is not limited to this configuration.

[0259] <Sixteenth Embodiment>

[0260] Please refer to Figure 17, which shows a schematic diagram of one side of an electronic device 400 according to the sixteenth embodiment of this disclosure. The electronic device 400 of the sixteenth embodiment is a smartphone, and the electronic device 400 includes image capturing devices 410, 420, 430, 440, 450, 460, 470, 480, 490 and a flash module 401.

[0261] The electronic device 400 of the sixteenth embodiment may include the same or similar components as those in the fourteenth embodiment described above, and the connection relationships between the image capturing devices 410, 420, 430, 440, 450, 460, 470, 480, 490 and the flash module 401 and other components may also be the same or similar as those disclosed in the fourteenth embodiment, and will not be repeated here. The image capturing devices 410, 420, 430, 440, 450, 460, 470, 480, and 490 in the sixteenth embodiment may all include the imaging optical system disclosed herein, and may all have the same or similar structure as the image capturing device 100 in the thirteenth embodiment described above, and will not be repeated here.

[0262] In detail, image capturing devices 410 and 420 can be ultra-wide-angle image capturing devices, image capturing devices 430 and 440 can be wide-angle image capturing devices, image capturing devices 450 and 460 can be telephoto image capturing devices, image capturing devices 470 and 480 can be telephoto image capturing devices (which may include optical path bending elements), and image capturing device 490 can be a TOF module, or other types of image capturing devices, and is not limited to this configuration.

[0263] <Seventeenth Embodiment>

[0264] Please refer to Figures 18A and 18B, where Figure 18A shows a schematic diagram of one side of an electronic device 500 according to the seventeenth embodiment of this disclosure, and Figure 18B shows a schematic diagram of the other side of the electronic device 500 according to Figure 18A. As can be seen from Figures 18A and 18B, the electronic device 500 of the seventeenth embodiment is a smartphone, and the electronic device 500 includes image capturing devices 510, 520, 530, 540 and a user interface 504.

[0265] The electronic device 500 of the seventeenth embodiment may include the same or similar components as those in the fourteenth embodiment, and the connection relationships between the image capturing devices 510, 520, 530, 540 and the user interface 504 and other components may also be the same or similar as those disclosed in the fourteenth embodiment, and will not be repeated here. In detail, the image capturing device 510 may capture an image through a non-circular opening on the outside of the electronic device, and the image capturing devices 520, 530, and 540 may be a telephoto image capturing device, a wide-angle image capturing device, and an ultra-wide-angle image capturing device, respectively, or may be other types of image capturing devices, and are not limited to this configuration.

[0266] <Eighteenth Embodiment>

[0267] Please refer to Figure 19, which illustrates a perspective view of an electronic device 600 according to the eighteenth embodiment of this disclosure. As shown in Figure 19, the electronic device 600 of the eighteenth embodiment is a drone, which includes an image-capturing device 610. The image-capturing device 610 may include the imaging optical system of this disclosure, and may have the same or similar structure as the image-capturing device 100 in the aforementioned thirteenth embodiment, which will not be described again here.

[0268] Although the present disclosure has been described above with reference to embodiments, it is not intended to limit the present disclosure. Anyone skilled in the art may make various modifications and alterations without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure shall be determined by the appended claims.

[0269] 200, 300, 400, 500, 600: Electronic devices 1,2,3,4,5,6,7,8,9,10,11,12,100,110,120,130,140,310,320,330,410,420,430,440,450,460,470,480,490,510,520,530,540,610: Image capturing device 101: Imaging Lens 102: Drive unit assembly 104: Image Stabilization Module 201, 301, 401: Flash module 202: Focusing Assist Module 203: Image Signal Processor 204, 504: User Interface 205: Image Software Processor 206: Subject IS,103: Electronic photosensitive element E1: First lens E2: Second lens E3: Third Lens E4: Fourth Lens E5: Fifth Lens E6: Sixth Lens E7: Seventh Lens E8: Eighth Lens E9: Filter element ST: Aperture S1, S2: Aperture IMG: Imaging Surface IP: Recurve Point CP: Critical Point f: Focal length of the imaging optical system f1: Focal length of the first lens f2: Focal length of the second lens f4: Focal length of the fourth lens f6: Focal length of the sixth lens f7: Focal length of the seventh lens f8: Focal length of the eighth lens f78: Combined focal length of the seventh and eighth lenses f123: The combined focal length of the first, second, and third lenses. f567: Combined focal length of the fifth, sixth, and seventh lenses R2: Radius of curvature of the image-side surface of the first lens R4: Radius of curvature of the image-side surface of the second lens V6: Abbe number of the sixth lens V8: Abbe number of the eighth lens TD: The distance on the optical axis from the object-side surface of the first lens to the image-side surface of the eighth lens. FOV: Maximum field of view in an imaging optical system BL: Distance along the optical axis from the image-side surface of the eighth lens to the imaging plane. ImgH: Maximum image height of the imaging optical system SL: Distance from the aperture to the imaging plane along the optical axis TL: Distance along the optical axis from the object-side surface of the first lens to the imaging plane. CT1: Thickness of the first lens on the optical axis CT2: Thickness of the second lens on the optical axis CT3: Thickness of the third lens on the optical axis CT4: Thickness of the fourth lens on the optical axis CT5: Thickness of the fifth lens on the optical axis CT6: Thickness of the sixth lens on the optical axis CT7: Thickness of the seventh lens on the optical axis CT8: Thickness of the eighth lens on the optical axis CTmax: The largest of CT1, CT2, CT3, CT4, CT5, CT6, CT7, and CT8. Dr3r6: Distance along the optical axis from the object-side surface of the second lens to the image-side surface of the third lens. Dr9r12: Distance on the optical axis from the object-side surface of the fifth lens to the image-side surface of the sixth lens. Dr1rs: Distance from the object-side surface of the first lens to the aperture along the optical axis T12: The distance between the first lens and the second lens on the optical axis T67: The distance between the sixth and seventh lenses on the optical axis ΣCT: The sum of the thicknesses of all lenses along the optical axis in an imaging optical system. ΣAT: The sum of the distances between two adjacent lenses on the optical axis in an imaging optical system. Fno: Aperture value of the imaging optics system HFOV: Half of the maximum field of view in an imaging optics system

Claims

1. An imaging optical system comprising eight lenses sequentially from the object side to the image side, wherein the eight lenses, from the object side to the image side, are: 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 lens having an object-side surface facing the object side and an image-side surface facing the image side; wherein, The first lens has negative refractive power; the second lens has negative refractive power and its image-side surface is concave near the optical axis; the fourth lens has its object-side surface concave near the optical axis; the fifth lens has its object-side surface convex near the optical axis; the sixth lens has negative refractive power; the eighth lens has an image-side surface containing at least one inflection point; wherein, the total number of lenses in the imaging optical system is eight; the focal length of the imaging optical system is f, the combined focal length of the seventh and eighth lenses is f78, the radius of curvature of the image-side surface of the first lens is R2, and the radius of curvature of the image-side surface of the second lens is R4, which satisfy the following conditions: -1.20 < f / f78 < 0.10; and 0.10 < |R2 / R4| < 10.

00.

2. The imaging optical system as claimed in claim 1, wherein the maximum field of view in the imaging optical system is FOV, which satisfies the following condition: 120.0 degrees < FOV < 190.0 degrees.

3. The imaging optical system as claimed in claim 1, wherein the distance from the image-side surface of the eighth lens to an imaging surface on the optical axis is BL, and the maximum image height of the imaging optical system is ImgH, which satisfies the following conditions: 0.50 < 10×BL / ImgH < 3.

00.

4. The imaging optical system of claim 1 further comprises: an aperture, the distance from the aperture to an imaging surface on the optical axis being SL, and the distance from the object-side surface of the first lens to the imaging surface on the optical axis being TL, which satisfies the following condition: 0.30 < SL / TL < 0.

55.

5. The imaging optical system as claimed in claim 1, wherein the thickness of the first lens on the optical axis is CT1, the thickness of the second lens on the optical axis is CT2, the thickness of the third lens on the optical axis is CT3, the thickness of the fourth lens on the optical axis is CT4, the thickness of the fifth lens on the optical axis is CT5, the thickness of the sixth lens on the optical axis is CT6, the thickness of the seventh lens on the optical axis is CT7, and the thickness of the eighth lens on the optical axis is CT8, wherein the largest of CT1, CT2, CT3, CT4, CT5, CT6, CT7, and CT8 is CTmax, and the focal length of the imaging optical system is f, which satisfies the following condition: 0.40 < CTmax / f < 1.

20.

6. The imaging optical system as claimed in claim 1, wherein the combined focal length of the first lens, the second lens and the third lens is f123, and the combined focal length of the fifth lens, the sixth lens and the seventh lens is f567, which satisfies the following condition: 0.60 < f123 / f567 < 8.

00.

7. The imaging optical system as claimed in claim 1, wherein the focal length of the sixth lens is f6 and the focal length of the eighth lens is f8, satisfying the following condition: 0.00 < |f6 / f8| < 2.

00.

8. The imaging optical system as claimed in claim 1, wherein the Abbe number of the eighth lens is V8, which satisfies the following condition: 5.0 < V8 < 30.

0.

9. An image capturing device, comprising: an imaging optical system as described in claim 1; and an electronic photosensitive element disposed on an imaging surface of the imaging optical system.

10. An electronic device comprising: an image capturing device as described in claim 9.

11. An imaging optical system comprising eight lenses sequentially from the object side to the image side, wherein the eight lenses, from the object side to the image side, are: 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 lens having an object-side surface facing the object side and an image-side surface facing the image side; wherein, The first lens has negative refractive power; the second lens has negative refractive power; the object-side surface of the fourth lens is concave near the optical axis; the sixth lens has negative refractive power; wherein, the total number of lenses in the imaging optical system is eight; the focal length of the first lens is f1, the focal length of the seventh lens is f7, and the Abbe number of the eighth lens is V8, which satisfy the following conditions: 0.00 < |f1 / f7| < 0.60; and 5.0 < V8 < 30.

0.

12. The imaging optical system of claim 11, wherein the third lens has positive refractive power; and the fifth lens has positive refractive power.

13. The imaging optical system of claim 11, wherein the distance from the object-side surface of the first lens to an imaging surface on the optical axis is TL, and the maximum image height of the imaging optical system is ImgH, which satisfies the following condition: 2.00 < TL / ImgH < 4.

00.

14. The imaging optical system as claimed in claim 11, wherein the maximum image height of the imaging optical system is ImgH and the focal length of the imaging optical system is f, which satisfies the following condition: 1.00 < ImgH / f < 2.

00.

15. The imaging optical system of claim 11, wherein the distance on the optical axis from the object-side surface of the first lens to the image-side surface of the eighth lens is TD, and the focal length of the imaging optical system is f, which satisfies the following condition: 2.50 < TD / f < 5.

00.

16. The imaging optical system of claim 11, wherein the distance from the image-side surface of the eighth lens to an imaging surface on the optical axis is BL, and the thickness of the third lens on the optical axis is CT3, which satisfies the following condition: 0.15 < BL / CT3 < 0.

70.

17. The imaging optical system of claim 11, wherein the distance on the optical axis from the object-side surface of the second lens to the image-side surface of the third lens is Dr3r6, and the distance on the optical axis from the object-side surface of the fifth lens to the image-side surface of the sixth lens is Dr9r12, which satisfies the following condition: 1.60 < Dr3r6 / Dr9r12 < 3.

00.

18. The imaging optical system of claim 11, wherein the distance between the first lens and the second lens on the optical axis is T12, and the distance between the sixth lens and the seventh lens on the optical axis is T67, which satisfies the following condition: 0.50 < T12 / T67 < 4.

00.

19. The imaging optical system of claim 11, wherein the third lens has the greatest thickness along the optical axis among the eight lenses.

20. An imaging optical system comprising eight lenses sequentially from the object side to the image side, wherein the eight lenses, from the object side to the image side, are: 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 lens having an object-side surface facing the object side and an image-side surface facing the image side; wherein, The first lens has negative refractive power; the second lens has negative refractive power; the object-side surface of the fourth lens is concave near the optical axis; the sixth lens has negative refractive power; the image-side surface of the eighth lens contains at least one inflection point; wherein, the total number of lenses in the imaging optical system is eight; the distance on the optical axis from the object-side surface of the first lens to the image-side surface of the eighth lens is TD; the focal length of the imaging optical system is f; the combined focal length of the seventh lens and the eighth lens is f78, which satisfies the following conditions: 2.00 < TD / f < 5.00; and -0.80 < f / f78 < 0.

00.

21. The imaging optical system of claim 20, wherein the image-side surface of the fourth lens is convex near the optical axis; and the object-side surface of the fifth lens is convex near the optical axis.

22. The imaging optical system of claim 20, wherein the object-side surface of the second lens includes at least one inflection point.

23. The imaging optical system of claim 20, wherein at least one of the third lens, the fourth lens and the fifth lens is made of glass.

24. The imaging optical system of claim 20, wherein the distance from the image-side surface of the eighth lens to an imaging plane on the optical axis is BL, and the focal length of the imaging optical system is f, which satisfies the following condition: 1.50 < 10 × BL / f < 4.

00.

25. The imaging optical system of claim 20, wherein the second lens has a focal length of f2 and the fourth lens has a focal length of f4, satisfying the following condition: 0.00 < |f2 / f4| < 1.

60.

26. The imaging optical system as claimed in claim 20, wherein the sum of the thicknesses of all lenses in the imaging optical system on the optical axis is ΣCT, and the sum of the distances between any two adjacent lenses in the imaging optical system on the optical axis is ΣAT, which satisfies the following condition: 1.20 < ΣCT / ΣAT < 2.

50.

27. The imaging optical system of claim 20 further comprises: an aperture, the distance from the object-side surface of the first lens to the aperture on the optical axis being Dr1rs, and the focal length of the imaging optical system being f, which satisfies the following condition: 1.50 < Dr1rs / f < 3.

50.

28. The imaging optical system of claim 20, wherein the Abbe number of the sixth lens is V6, which satisfies the following condition: 5.0 < V6 < 26.

0.

29. The imaging optical system of claim 20, wherein the focal length of the imaging optical system is f, the combined focal length of the seventh lens and the eighth lens is f78, the radius of curvature of the image-side surface of the first lens is R2, the radius of curvature of the image-side surface of the second lens is R4, the focal length of the first lens is f1, the focal length of the seventh lens is f7, the Abbe number of the eighth lens is V8, and the distance on the optical axis from the object-side surface of the first lens to the image-side surface of the eighth lens is TD, which satisfies the following conditions: -0.43 ≤ f / f78 ≤ -0.10; 0.53 ≤ |R2 / R4| ≤ 0.69; 0.01 ≤ |f1 / f7| ≤ 0.22; 18.2 ≤ V8 ≤ 25.6; and 3.49 ≤ TD / f ≤ 4.55.

Images