Optical system, image capturing module and electronic device

Abstract

This application relates to an optical system, an image-capturing module, and an electronic device. The optical system, along the optical axis from the object side to the image side, sequentially includes: a first lens with positive optical power; a second lens with negative optical power, whose object-side surface is convex near the optical axis and convex near the circumference; a third lens with optical power; a fourth lens with positive optical power; a fifth lens with negative optical power, whose object-side surface is concave near the optical axis and concave near the circumference, wherein both the object-side and image-side surfaces of the fifth lens are aspherical, and at least one surface of the object-side and image-side surfaces contains at least one inflection point; and a sixth lens with negative optical power, whose object-side surface is convex near the optical axis and convex near the circumference. The above optical system, when satisfying specific relationships, achieves a balance between achieving a small head size, expanding the field of view, and ensuring high-quality imaging.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and in particular to an optical system, an image acquisition module, and an electronic device. Background Technology

[0002] With the continuous development of camera-related technologies, photography has become a standard feature of smart electronic products. Consumers have increasingly higher demands for electronic products with ideal photo-taking effects. Some high-pixel optical lenses, combined with optimized software algorithms, produce excellent photo-taking results, providing consumers with a superb experience. However, with the improvement in performance and the increase in size of commonly used photosensitive elements such as charge-coupled devices (CCDs) and complementary metal-oxide-semiconductor devices (CMOS), the number of pixels on the photosensitive elements has also increased while the pixel size has become smaller. This places higher demands on the imaging resolution and miniaturization of imaging lenses.

[0003] On the other hand, the emergence of punch-hole screens on mobile phones has particularly attracted consumers' attention. The camera module is encapsulated in a very small area of ​​the screen, which is closely related to the design of the lens and places increasingly higher demands on lens specifications. Therefore, how to design a mobile phone lens with a small aperture, long depth, a wide field of view, and high image quality has become an urgent problem to be solved. Summary of the Invention

[0004] Therefore, it is necessary to provide an improved optical system to address the problem that traditional wide-angle lenses struggle to balance small head size and high image quality.

[0005] An optical system comprising, in sequence along the optical axis from the object side to the image side:

[0006] A first lens with positive optical power;

[0007] A second lens with negative optical power, wherein the object-side surface of the second lens is convex near the optical axis and convex near the circumference;

[0008] A third lens with optical power;

[0009] A fourth lens with positive optical power;

[0010] A fifth lens having negative optical power, wherein the object-side surface of the fifth lens is concave near the optical axis and concave near the circumference, and both the object-side and image-side surfaces of the fifth lens are aspherical, and at least one of the object-side and image-side surfaces contains at least one inflection point; and,

[0011] A sixth lens with negative optical power, wherein the object-side surface of the sixth lens is convex near the optical axis and convex near the circumference;

[0012] The optical system satisfies the following relationship:

[0013] 0.24mm -1 <tan(HFOV) / TTL<0.34mm -1 ;

[0014] Wherein, HFOV represents half of the maximum field of view of the optical system, and TTL represents the distance on the optical axis from the object side of the first lens to the imaging surface of the optical system.

[0015] The aforementioned optical system, by selecting an appropriate number of lenses and rationally allocating the refractive power and surface shape of each lens, can enhance the system's imaging resolution and effectively correct aberrations, ensuring image clarity. In addition, when the above relationship is satisfied, the field of view will not be too large, which helps the system collect light and thus improves the system's imaging quality. At the same time, the overall system length will not be too large, which is conducive to the compact arrangement of the system structure and achieves miniaturization.

[0016] In one embodiment, the optical system satisfies the following relationship: -13 < f2 / f1 < -1; where f1 represents the effective focal length of the first lens and f2 represents the effective focal length of the second lens.

[0017] When the above relationship is satisfied, the optical power of the first lens and the second lens can be reasonably allocated and the lens shape can be reasonably configured, which is beneficial to expanding the field of view of the system. At the same time, the combination of positive and negative lenses can cancel out the spherical aberration they produce. When the second lens provides negative refractive power, it can not only correct the spherical aberration produced by the first lens, but also further expand the field of view of the optical system.

[0018] In one embodiment, the optical system satisfies the following relationship: 45deg≤HFOV≤51deg; and TTL<4.1mm.

[0019] When the above relationship is satisfied, the characteristics of a large angle of view and short total length of the optical system can be more clearly demonstrated. At the same time, the field of view can be avoided from being too large, thereby preventing insufficient edge light collection capability of the system, resulting in low illumination at the edge of the field of view and reduced image quality.

[0020] In one embodiment, the optical system satisfies the following relationship: 0.25 < ET4 / CT4 < 0.4; where CT4 represents the thickness of the fourth lens on the optical axis, and ET4 represents the distance along the optical axis from the maximum effective aperture on the object side of the fourth lens to the maximum effective aperture on its image side.

[0021] When the above relationship is satisfied, the shape and thickness ratio of the fourth lens can be effectively controlled, thereby reducing the difficulty of lens forming and effectively correcting system distortion, ensuring the imaging quality of the optical system.

[0022] In one embodiment, the optical system satisfies the following relationship:

[0023] 0.8 < (CT1 + CT2 + CT3) / SD32 < 1.1; where CT1 represents the thickness of the first lens on the optical axis, CT2 represents the thickness of the second lens on the optical axis, CT3 represents the thickness of the third lens on the optical axis, and SD32 represents the maximum effective half-aperture of the image side of the third lens.

[0024] When the above relationship is satisfied, the depth of the system head can be increased, so that the system head can extend out during assembly and get closer to the screen glass, which is beneficial for the design of small head lens modules; at the same time, by selecting an appropriate ratio of the thickness of the front lens to the maximum effective half-aperture of the third lens, it is beneficial to reduce the head aperture of the system, increase the screen ratio, and reduce the tolerance and assembly sensitivity of the optical system.

[0025] In one embodiment, the optical system satisfies the following relationship: -3 < f4 / RS8 < -2; where f4 represents the effective focal length of the fourth lens, and RS8 represents the radius of curvature of the image side of the fourth lens at the optical axis.

[0026] When the above relationship is satisfied, the relationship between the effective focal length of the fourth lens and the radius of curvature of the image side of the fourth lens at the optical axis can be reasonably configured, thereby effectively controlling the incident angle of light entering the photosensitive element, improving the optical distortion of the system, making the system have smaller TV distortion, and improving the imaging quality.

[0027] In one embodiment, the optical system satisfies the following relationship: 1 < RS10 / f5 < 8; where f5 represents the effective focal length of the fifth lens, and RS10 represents the radius of curvature of the image side of the fifth lens at the optical axis.

[0028] When the above relationship is satisfied, the field of view of the system can be effectively expanded, and it is also beneficial to improve the astigmatism of the system and improve the imaging quality of the optical system.

[0029] In one embodiment, the optical system satisfies the following relationship: 0.5 < f6 / f5 < 2; where f5 represents the effective focal length of the fifth lens and f6 represents the effective focal length of the sixth lens.

[0030] When the above relationship is satisfied, it is beneficial to rationally configure the effective focal length of the fifth and sixth lenses, thereby effectively counteracting the spherical aberration generated by the front lens group of the optical system. It is also beneficial to increase the optical back focal length of the system, providing sufficient matching space for the photosensitive element, facilitating the assembly and adjustment of the photosensitive element, and thus helping to better achieve the incident angle matching of the main ray on the photosensitive element, thereby improving the imaging quality.

[0031] In one embodiment, the optical system satisfies the following relationship: 1 < vd2 - vd3 < 40; where vd2 represents the d-Abbe number of the second lens and vd3 represents the d-Abbe number of the third lens.

[0032] When the above relationship is satisfied, it is beneficial to select a suitable lens material, which can effectively correct chromatic aberration, avoid severe purple fringing during system shooting, and thus improve the imaging clarity and image quality of the optical system.

[0033] In one embodiment, the optical system satisfies the following relationship: 0.5 < RS6 / RS5 < 10; where RS5 represents the radius of curvature of the object side of the third lens at the optical axis, and RS6 represents the radius of curvature of the image side of the third lens at the optical axis.

[0034] When the above relationship is satisfied, the surface shape of the third lens can be effectively controlled. When the third lens has negative optical power, it is beneficial to increase the field of view of the system. When the third lens has positive optical power, it can help the first lens share part of the positive refractive power, making the surface shape of the two adjacent lenses more compact, the overall surface shape of the system smoother, and the lens arrangement more compact. This can reasonably compress the arrangement space of the rear lens group, further shorten the total length of the optical system, and at the same time, it can also provide sufficient light focusing for the rear lens group, which is beneficial to balance various aberrations while shortening the total length.

[0035] In one embodiment, the optical system satisfies the following relationship: -9.5mm 2 <f6*RS11<-4.5mm 2 Where f6 represents the effective focal length of the sixth lens, and RS11 represents the radius of curvature of the object side of the sixth lens at the optical axis.

[0036] When the above relationship is satisfied, the radius of curvature of the side surface of the sixth lens at the optical axis can be corrected, thereby reducing the incident angle of light entering the side surface of the sixth lens, so as to effectively correct the astigmatism of the system; at the same time, stray light can be reduced, and the probability of ghosting can be lowered; and the surface shape of the sixth lens can also be effectively controlled to avoid its surface shape change being too large to affect the arrangement of the lens group, thereby facilitating the compression of the overall length of the optical system and realizing the thinning of the system.

[0037] This application also provides an image acquisition module.

[0038] An image-capturing module includes an optical system as described above and a photosensitive element, wherein the photosensitive element is disposed on the image side of the optical system.

[0039] The aforementioned image-capturing module, utilizing the aforementioned optical system, can capture images with a wide viewing angle and high quality. At the same time, the image-capturing module also features a small head and short overall length, which can effectively improve the screen-to-body ratio and facilitate adaptation to devices with limited size, such as mobile phones and tablets, thus better meeting market demands.

[0040] This application also provides an electronic device.

[0041] An electronic device includes a housing and an image-capturing module as described above, the image-capturing module being mounted on the housing.

[0042] The aforementioned electronic device is lightweight and, by utilizing the aforementioned image-capturing module, can achieve clear large-scene photography, which helps to improve the user's shooting experience. Attached Figure Description

[0043] Figure 1 A schematic diagram of the optical system of Embodiment 1 of this application is shown;

[0044] Figure 2 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of Example 1 are shown respectively.

[0045] Figure 3 A schematic diagram of the optical system of Embodiment 2 of this application is shown;

[0046] Figure 4 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of Example 2 are shown respectively.

[0047] Figure 5 A schematic diagram of the optical system of Embodiment 3 of this application is shown;

[0048] Figure 6 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of Example 3 are shown respectively.

[0049] Figure 7 A schematic diagram of the optical system of Embodiment 4 of this application is shown;

[0050] Figure 8 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of Example 4 are shown respectively.

[0051] Figure 9 A schematic diagram of the optical system of Embodiment 5 of this application is shown;

[0052] Figure 10 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of Example 5 are shown respectively.

[0053] Figure 11 A schematic diagram of the optical system of Embodiment 6 of this application is shown;

[0054] Figure 12 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of Example 6 are shown respectively.

[0055] Figure 13 A schematic diagram of an image-capturing module according to an embodiment of this application is shown;

[0056] Figure 14 A schematic diagram of an electronic device using an image-capturing module according to an embodiment of this application is shown. Detailed Implementation

[0057] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0058] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," "upper," "lower," "front," "rear," "circumferential," and similar expressions used herein are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0060] In this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as a second lens or a third lens. For ease of illustration, the shapes of the spherical or aspherical surfaces shown in the accompanying drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not strictly to scale.

[0061] In this specification, the space on which the object lies relative to the optical element is called the object side of the optical element, and correspondingly, the space on which the image formed by the object lies relative to the optical element is called the image side of the optical element. The surface of each lens closest to the object is called the object side, and the surface of each lens closest to the imaging plane is called the image side. The distance from the object side to the image side is defined as the positive direction.

[0062] Furthermore, in the following description, if a lens surface is convex without defining its location, it means that the lens surface is convex at least near the optical axis; if a lens surface is concave without defining its location, it means that the lens surface is concave at least near the optical axis. Here, "near the optical axis" refers to the region near the optical axis. Specifically, the convexity or concavity of a lens surface region is determined by whether the intersection of a parallel ray passing through that region and the optical axis is on the image side or the object side. For example, if a parallel ray passes through that region and focuses towards the image side with its intersection with the optical axis on the image side, then that region is convex; conversely, if a ray passes through that region and diverges with its extension intersecting the optical axis on the object side, then that region is concave. Additionally, a lens includes a region near the optical axis, a region near the circumference, and an extension for fixing the lens. Ideally, imaging rays do not pass through the extension; therefore, the region from the region near the optical axis to the region near the circumference can be defined as the effective aperture range of the lens. For the sake of brevity, some extended portions have been omitted in the following embodiments. Furthermore, the method for determining the range of the region near the optical axis, the region near the circumference, or multiple regions is as follows:

[0063] First, define a midpoint as the intersection of the lens surface and the optical axis. The distance from the midpoint to the boundary of the lens's effective aperture range is defined as the effective half-aperture of the lens. A recurve point is a point on the lens surface that is not located on the optical axis. A tangent line passing through a recurve point is perpendicular to the optical axis (i.e., the surface shapes on both sides of the recurve point on the lens surface are opposite). If there are several recurve points radially outward from the midpoint of the lens, they are sequentially designated as the first recurve point, the second recurve point, and the recurve point farthest from the midpoint within the effective aperture range is designated as the Nth recurve point. Define the area between the midpoint and the first recurve point as the region near the optical axis, and the area radially outward from the Nth recurve point as the region near the circumference. The region between the first and Nth recurve points is divided into different regions depending on each recurve point. If there are no recurve points on the lens surface, the region near the optical axis is defined as the region corresponding to 0%–50% of the effective half-aperture, and the region near the circumference is defined as the region corresponding to 50%–100% of the effective half-aperture.

[0064] The features, principles and other aspects of this application will be described in detail below.

[0065] Please refer to the following: Figure 1 , Figure 3 , Figure 5 , Figure 7 , Figure 9 and Figure 11 This application provides an optical system with a small head that balances wide viewing angle and high imaging quality. The optical system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. These six lenses are arranged sequentially along the optical axis from the object side to the image side, with the imaging surface of the optical system located on the image side of the sixth lens. Specifically, these six lenses are non-jointed, meaning there is a gap between any two adjacent lenses. Since the manufacturing process of joined lenses is more complex than that of non-jointed lenses, especially since the joining surfaces of the two lenses require highly accurate curved surfaces to achieve a high degree of fit, and misalignment during the joining process can also lead to poor fit, affecting the overall optical imaging quality. Therefore, the six lenses in the optical system of this invention are non-jointed lenses, which effectively improves the problems caused by joined lenses.

[0066] Specifically, the first lens has positive optical power, which helps light to converge into the system and focus on the imaging surface, and also helps to shorten the overall length of the system and achieve miniaturization of the system.

[0067] The second lens has negative optical power, which helps correct the spherical aberration produced by the first lens and further expands the field of view of the optical system. Furthermore, the object-side surface of the second lens is convex near the optical axis and convex near the circumference, which helps to focus light and ensure image sharpness.

[0068] The third lens has either positive or negative optical power. When the third lens has positive optical power, it can help the first lens share some of the positive refractive power and further shorten the overall length of the system. When the third lens has negative optical power, it helps to expand the field of view of the optical system.

[0069] The fourth lens has positive optical power, which can effectively improve the optical distortion of the system and further enhance the imaging quality of the system.

[0070] The fifth lens has negative optical power, and the object side of the fifth lens is concave near the optical axis and concave near the circumference, which helps to expand the system's field of view, correct the system's spherical aberration, and also helps to increase the system's optical back focal length, thereby improving the system's imaging quality.

[0071] Furthermore, both the object-side and image-side surfaces of the fifth lens are aspherical. Aspherical lenses are characterized by a continuously changing curvature from the lens center to the periphery, unlike spherical lenses which have a constant curvature from the center to the periphery. Aspherical lenses offer superior imaging characteristics, improving edge aberrations and reducing astigmatism. This approach enhances the flexibility of lens design, effectively corrects aberrations, and improves the imaging quality of the optical system. Moreover, at least one surface on the object-side and image-side surfaces of the fifth lens contains at least one inflection point. This helps reduce the incidence angle of the principal ray in the off-axis field of view on the imaging plane, improving the response efficiency of pixel units in the edge region of the sensor, ensuring illumination in the edge field of view, and thus reducing off-axis field-of-view aberrations and improving the system's imaging resolution.

[0072] The sixth lens has negative optical power, and its object-side surface is convex near the optical axis and convex near the circumference. This allows it to work in conjunction with the fifth lens to correct spherical aberration produced by the preceding lens group in the system. It also helps correct astigmatism and reduces stray light, lowering the probability of ghosting. In addition, it helps to compress the overall length of the optical system, enabling a thinner system.

[0073] Furthermore, the optical system satisfies the following relationship: 0.24mm -1 <tan(HFOV) / TTL<0.34mm -1 Where HFOV represents half of the maximum field of view of the optical system, and TTL represents the distance on the optical axis from the object side of the first lens to the imaging plane of the optical system. Furthermore, in this application, half of the maximum field of view refers to the angle between the incident ray at its maximum angle and the optical axis of the system. tan(HFOV) / TTL can be 0.25mm. -1 0.26mm -1 0.27mm -1 0.28mm -1 0.29mm -10.3mm -1 0.31mm -1 0.32mm -1 or 0.33mm -1 When the above relationship is satisfied, the field of view will not be too large, which helps the system collect light and thus improves the system's imaging quality. At the same time, the overall system length will not be too large, which is conducive to the compact arrangement of the system structure and the realization of miniaturization. However, when tan(HFOV) / TTL is lower than the lower limit, the system's field of view is too small to meet the shooting requirements, or the overall system length is too long, which is not conducive to miniaturization. On the other hand, when tan(HFOV) / TTL is higher than the upper limit, the system's field of view is too large, which can easily lead to insufficient light collection capability and thus reduce imaging quality.

[0074] When the aforementioned optical system is used for imaging, the light emitted or reflected by the object enters the optical system from the object side and passes through the first lens, second lens, third lens, fourth lens, fifth lens and sixth lens in sequence, finally converging on the imaging surface.

[0075] The aforementioned optical system, by selecting an appropriate number of lenses and rationally allocating the refractive power and surface shape of each lens, can enhance the imaging resolution of the optical system and effectively correct aberrations, ensuring image clarity. In addition, when the system's field of view and total system length satisfy a specific relationship, it helps the system collect light, thereby improving the system's imaging quality. At the same time, the total system length will not be too large, which is conducive to the compact arrangement of the system structure and the realization of miniaturization.

[0076] In an exemplary embodiment, the object-side and image-side surfaces of the first to sixth lenses can both be aspherical. The characteristics of aspherical lenses have been described above and will not be repeated here. This approach improves the flexibility of lens design, effectively corrects aberrations, and enhances the imaging quality of the optical system. Setting both the object-side and image-side surfaces of the first to sixth lenses aspherical allows for better correction of aberrations generated during light transmission. It should be noted that, without departing from the technical solution of the optical system of this application, the surfaces of each lens can also be any combination of spherical and aspherical surfaces; this application does not impose any restrictions on this.

[0077] In an exemplary embodiment, the optical system satisfies the following relationship: -13 < f2 / f1 < -1; where f1 represents the effective focal length of the first lens and f2 represents the effective focal length of the second lens. f2 / f1 can be -12, -11, -9, -7, -6, -5, -4, -3, or -2. When the above relationship is satisfied, the optical power of the first and second lenses can be reasonably allocated and the lens shapes can be reasonably configured, which is beneficial to expanding the field of view of the system. At the same time, the combination of positive and negative lenses can cancel out the spherical aberrations they produce. The second lens provides negative refractive power, which can not only correct the spherical aberration produced by the first lens, but also further expand the field of view of the optical system. However, when f2 / f1 is lower than the lower limit or higher than the upper limit, the optical power of the first or second lens is likely to exceed the reasonable value, which will make it impossible to guarantee the field of view of the system and easily introduce additional aberrations, reducing the image quality.

[0078] In an exemplary embodiment, the optical system satisfies the following relationship: 45deg ≤ HFOV ≤ 51deg; and TTL < 4.1mm. HFOV can be 45deg, 46deg, 47deg, 48deg, 49deg, 50deg, or 51deg, and TTL can be 3.7mm, 3.8mm, 3.85mm, 3.9mm, 3.95mm, or 4.0mm. By controlling HFOV and TTL to satisfy the above relationship, the characteristics of a large viewing angle and short overall length of the optical system can be more specifically demonstrated. At the same time, it can avoid an excessively large field of view, preventing insufficient edge light collection capability of the system from causing low illumination at the edge of the field of view and reducing image quality.

[0079] In an exemplary embodiment, the optical system satisfies the following relationship: 0.25 < ET4 / CT4 < 0.4; where CT4 represents the thickness of the fourth lens on the optical axis, and ET4 represents the distance along the optical axis from the maximum effective aperture on the object side of the fourth lens to the maximum effective aperture on its image side. ET4 / CT4 can be 0.28, 0.3, 0.32, 0.33, 0.34, 0.35, 0.36, or 0.38. Satisfying the above relationship effectively controls the shape and thickness ratio of the fourth lens, thereby reducing the difficulty of lens forming and effectively correcting system distortion, ensuring the imaging quality of the optical system. When ET4 / CT4 is below the lower limit, the edge thickness of the fourth lens is too thin, and the center thickness is too thick, making lens forming difficult; while when ET4 / CT4 is above the upper limit, the edge thickness of the fourth lens is too thick, resulting in insufficient space for system distortion and aberration correction, affecting the imaging quality of the system.

[0080] In an exemplary embodiment, the optical system satisfies the following relationship:

[0081] 0.8 < (CT1 + CT2 + CT3) / SD32 < 1.1; where CT1 represents the thickness of the first lens on the optical axis, CT2 represents the thickness of the second lens on the optical axis, CT3 represents the thickness of the third lens on the optical axis, and SD32 represents the maximum effective half-aperture of the third lens on the image side. (CT1 + CT2 + CT3) / SD32 can be 0.85, 0.9, 0.93, 0.95, 1.0, 1.02, or 1.05. When the above relationship is satisfied, the head depth of the system can be increased, allowing the system head to extend further during assembly and get closer to the screen glass, which is beneficial for the design of small-head lens modules. Simultaneously, by selecting an appropriate ratio of the front lens thickness to the maximum effective half-aperture of the third lens, it is beneficial to reduce the head aperture of the system, increase the screen-to-body ratio, and reduce the tolerance and assembly sensitivity of the optical system. When (CT1+CT2+CT3) / SD32 is below the lower limit, the thickness of the middle part of the first lens, the second lens and the third lens is too thin, which can easily lead to an increase in the sensitivity of the optical system; when (CT1+CT2+CT3) / SD32 is above the upper limit, the thickness of the middle part of the first lens, the second lens and the third lens is too thick, which is not conducive to the miniaturization of the optical system.

[0082] In an exemplary embodiment, the optical system satisfies the following relationship: -3 < f4 / RS8 < -2; where f4 represents the effective focal length of the fourth lens, and RS8 represents the radius of curvature of the image-side surface of the fourth lens at the optical axis. f4 / RS8 can be -2.9, -2.8, -2.7, -2.6, -2.5, -2.4, -2.3, -2.2, or -2.1. When the above relationship is satisfied, the relationship between the effective focal length of the fourth lens and the radius of curvature of the image-side surface of the fourth lens at the optical axis can be reasonably configured, thereby effectively controlling the incident angle of light entering the photosensitive element, improving the optical distortion of the system, giving the system a smaller TV distortion, and improving image quality. However, when f4 / RS8 is below the lower limit or above the upper limit, the refractive power of the fourth lens is too strong or too weak, both of which are not conducive to controlling the incident angle of the principal ray of the system, making distortion correction difficult.

[0083] In an exemplary embodiment, the optical system satisfies the following relationship: 1 < RS10 / f5 < 8; where f5 represents the effective focal length of the fifth lens, and RS10 represents the radius of curvature of the image-side surface of the fifth lens at the optical axis. RS10 / f5 can be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 2, 4, 6, 7, or 7.5. Satisfying the above relationship effectively expands the system's field of view and also helps improve astigmatism and enhances the imaging quality of the optical system. However, when RS10 / f5 is below the lower limit, the negative refractive power provided by the fifth lens is insufficient, easily leading to excessive spherical aberration in the system; while when RS10 / f5 is above the upper limit, excessive bending occurs at the edges of the fifth lens, resulting in increased stray light in the system and affecting imaging quality.

[0084] In an exemplary embodiment, the optical system satisfies the following relationship: 0.5 < f6 / f5 < 2; where f5 represents the effective focal length of the fifth lens and f6 represents the effective focal length of the sixth lens. f6 / f5 can be 0.6, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, or 1.9. Satisfying this relationship facilitates the rational configuration of the effective focal lengths of the fifth and sixth lenses, effectively counteracting the spherical aberration generated by the front lens group of the optical system. It also increases the optical back focal length of the system, providing sufficient matching space for the photosensitive element, facilitating the assembly and adjustment of the photosensitive element, and thus helping to better match the incident angle of the principal ray on the photosensitive element, improving image quality. When f6 / f5 is below the lower limit, the refractive power of the fifth lens is insufficient, easily leading to difficulties in spherical aberration correction; when f6 / f5 is above the upper limit, the refractive power of the fifth lens is too strong, easily causing excessive aberration correction in the system, affecting the image quality of the system.

[0085] In an exemplary embodiment, the optical system satisfies the following relationship: 1 < vd2 - vd3 < 40; where vd2 represents the d-Abbe number of the second lens, vd3 represents the d-Abbe number of the third lens, and d-light represents yellow light with a wavelength of 587.56 nm. vd2-vd3 can be 2, 2.5, 4, 10, 13, 15, 18, 20, 25, 30, or 35. Satisfying the above relationship facilitates the selection of suitable lens materials, thereby effectively correcting chromatic aberration, avoiding severe purple fringing during system shooting, and thus improving the imaging sharpness and image quality of the optical system.

[0086] In an exemplary embodiment, the optical system satisfies the following relationship: 0.5 < RS6 / RS5 < 10; where RS5 represents the radius of curvature of the object-side surface of the third lens at the optical axis, and RS6 represents the radius of curvature of the image-side surface of the third lens at the optical axis. RS6 / RS5 can be 0.7, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, or 9. When the above relationship is satisfied, the surface shape of the third lens can be effectively controlled. Therefore, when the third lens has negative optical power, it is beneficial to increase the system's field of view. When the third lens has positive optical power, the surface shapes of adjacent lenses are more compact, the overall system surface is smoother, and the lens arrangement is more compact. This allows for reasonable compression of the arrangement space of the subsequent lens groups, further shortening the overall length of the optical system. Simultaneously, it provides sufficient light focusing for the subsequent lens groups, which is beneficial for balancing various aberrations while shortening the overall length. When RS6 / RS5 is below the lower limit or above the upper limit, it can easily cause the image side or object side of the third lens to bend excessively, which is not conducive to lens shaping and can easily lead to an increase in stray light and reduce image quality.

[0087] In an exemplary embodiment, the optical system satisfies the following relationship: -9.5mm 2 <f6*RS11<-4.5mm 2 Where f6 represents the effective focal length of the sixth lens, and RS11 represents the radius of curvature of the object-side surface of the sixth lens at the optical axis. f6*RS11 can be -9mm. 2 -8.5mm 2 -8mm 2 -7.5mm 2 -7mm 2 -6.5mm 2 -6mm 2 -5.5mm 2 or -5mm 2 When the above relationship is satisfied, the radius of curvature of the side surface of the sixth lens can be corrected, thereby reducing the incident angle of light entering the side surface of the sixth lens, effectively correcting the astigmatic aberration of the system; at the same time, stray light can be reduced, lowering the probability of ghosting; and it is also beneficial to compress the overall length of the optical system, achieving system thinning. However, when f6*RS11 is below the lower limit or above the upper limit, the side surface of the sixth lens is prone to being too flat or too curved, resulting in insufficient or excessive refractive power of the sixth lens, which is not conducive to controlling the incident angle on the side surface of the sixth lens, failing to effectively correct the astigmatic aberration of the system, and also affecting the thinning of the system.

[0088] In an exemplary embodiment, the optical system also includes an aperture stop to better control the size of the incident beam and improve the imaging quality of the optical system. Further, the aperture stop is located on the object side of the first lens, or between the first and second lenses. Preferably, the aperture stop is an aperture stop. The aperture stop can be located on the surface of the lens (e.g., the object side and the image side) and interact with the lens. For example, an aperture stop can be formed on the surface of the lens by coating the surface with a light-blocking coating; or it can be fixedly clamped to the surface of the lens by a clamping member, the clamping member structure located on the surface being able to limit the width of the on-axis object point imaging beam, thereby forming an aperture stop on the surface.

[0089] In an exemplary embodiment, a filter is further disposed between the sixth lens and the imaging surface of the optical system to filter out light outside the working wavelength range, thereby preventing false colors or ripples caused by interference from light outside the working wavelength range and avoiding color distortion in the imaging. Specifically, the filter can be an infrared cut-off filter made of glass.

[0090] In an exemplary embodiment, the lenses in the optical system can be made of either glass or plastic. Plastic lenses reduce the weight of the optical system and lower production costs, while glass lenses provide better temperature resistance and superior optical performance. Furthermore, when the optical system is applied to a mobile phone or tablet, plastic is the preferred material for the lenses to reduce the weight and lower production costs while still meeting imaging performance requirements. It should be noted that the lenses in the optical system can also be any combination of glass and plastic; they do not necessarily have to be made entirely of glass or entirely of plastic.

[0091] In an exemplary embodiment, the optical system may further include a protective glass. The protective glass is disposed on the image side of the sixth lens or the image side of the filter, serving to protect the photosensitive element and also preventing dust from settling on the image sensitive element, further ensuring image quality. It should be noted that when the optical system is applied to electronic devices such as mobile phones and tablets, a protective glass may not be necessary to further reduce the weight of the electronic device.

[0092] The optical system of the embodiments described above in this application can employ multiple lenses, such as the six lenses mentioned above. By rationally allocating the focal length, refractive power, surface shape, thickness, and on-axis spacing between each lens, the optical system can possess characteristics such as a large field of view, small overall length, and high imaging quality, thereby better meeting the application requirements of electronic devices such as mobile phones and tablets. However, those skilled in the art should understand that, without departing from the technical solutions claimed in this application, the number of lenses constituting the optical system can be changed to obtain the various results and advantages described in this specification.

[0093] Specific embodiments of the optical system applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0094] Example 1

[0095] The following is for reference Figures 1 to 2 The optical system 100 of Embodiment 1 of this application is described.

[0096] Figure 1 A schematic diagram of the optical system 100 of Embodiment 1 is shown. Figure 1 As shown, the optical system 100 includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and an imaging plane S15.

[0097] The first lens L1 has positive refractive power. Its object-side surface S1 and image-side surface S2 are both aspherical. The object-side surface S1 is convex near the optical axis and convex near the circumference. The image-side surface S2 is concave near the optical axis and concave near the circumference.

[0098] The second lens L2 has negative refractive power. Its object-side surface S3 and image-side surface S4 are both aspherical. The object-side surface S3 is convex near the optical axis and convex near the circumference. The image-side surface S4 is concave near the optical axis and concave near the circumference.

[0099] The third lens L3 has negative refractive power. Its object-side surface S5 and image-side surface S6 are both aspherical. The object-side surface S5 is concave near the optical axis and concave near the circumference. The image-side surface S6 is convex near the optical axis and convex near the circumference.

[0100] The fourth lens L4 has positive refractive power. Its object-side surface S7 and image-side surface S8 are both aspherical. The object-side surface S7 is concave near the optical axis and convex near the circumference. The image-side surface S8 is convex near the optical axis and convex near the circumference.

[0101] The fifth lens L5 has negative refractive power. Its object-side surface S9 and image-side surface S10 are both aspherical. The object-side surface S9 is concave near the optical axis and concave near the circumference. The image-side surface S10 is concave near the optical axis and convex near the circumference.

[0102] The sixth lens L6 has negative refractive power. Its object-side surface S11 and image-side surface S12 are both aspherical. The object-side surface S11 is convex near the optical axis and convex near the circumference. The image-side surface S12 is concave near the optical axis and convex near the circumference.

[0103] Setting the object-side and image-side surfaces of the first lens L1 to the sixth lens L6 as aspherical is beneficial for correcting aberrations and solving the problem of image plane distortion. It also enables the lenses to achieve excellent optical imaging effects in a smaller, thinner, and flatter form, thereby giving the optical system 100 miniaturization characteristics.

[0104] An aperture stop STO is also provided on the object side of the first lens L1 to limit the size of the incident beam and further improve the imaging quality of the optical system 100. The optical system 100 also includes a filter 110 disposed on the image side of the sixth lens L6, having an object side surface S13 and an image side surface S14. Light from the object OBJ passes sequentially through each surface S1 to S14 and is finally imaged on the imaging surface S15. The filter 110 is used to filter out light outside the working wavelength range, thereby preventing false colors or ripples caused by interference from light outside the working wavelength range, and avoiding color distortion in the imaging. Specifically, the filter 110 is an infrared cutoff filter, and its material is glass.

[0105] Table 1 shows the surface type, radius of curvature, thickness, material, refractive index, Abbe number (i.e., dispersion coefficient), and effective focal length of the lens in the optical system 100 of Embodiment 1. The reference wavelength for the effective focal length, refractive index, and Abbe number is 587.56 nm. The units for the radius of curvature, thickness, and effective focal length are millimeters (mm). Furthermore, the first value in the "Thickness" parameter column of the lens is the thickness of the lens on the optical axis, and the second value is the distance on the optical axis from the image-side surface of the lens to the rear surface in the image-side direction. The value of the stop ST0 in the "Thickness" parameter column is the distance on the optical axis from the stop ST0 to the vertex of the rear surface (the vertex refers to the intersection of the surface and the optical axis). We assume that the direction from the object-side surface of the first lens L1 to the image-side surface of the last lens is the positive direction of the optical axis. When this value is negative, it indicates that the stop ST0 is located to the right of the vertex of the surface. If the thickness of the stop ST0 is positive, the stop is to the left of the vertex of the surface.

[0106] Table 1

[0107]

[0108]

[0109] The aspherical surface shape in a lens is defined by the following formula:

[0110]

[0111] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1); k is the conic coefficient; Ai is the i-th order coefficient of the aspherical surface. Table 2 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for the aspherical surfaces S1-S12 of the lens in Example 1.

[0112] Table 2

[0113]

[0114] The distance TTL on the optical axis from the object surface S1 of the first lens L1 to the imaging surface S15 of the optical system 100 is 4.0 mm. Combining the data in Tables 1 and 2, it can be seen that the optical system 100 in Example 1 satisfies:

[0115] tan(HFOV) / TTL = 0.259 mm -1 Where HFOV represents half of the maximum field of view of the optical system 100, and TTL represents the distance on the optical axis from the object surface S1 of the first lens L1 to the imaging surface S15 of the optical system 100.

[0116] f2 / f1 = -11.73, where f1 represents the effective focal length of the first lens L1 and f2 represents the effective focal length of the second lens L2.

[0117] HFOV = 46deg, TTL = 4.0mm.

[0118] ET4 / CT4 = 0.358, where CT4 represents the thickness of the fourth lens L4 on the optical axis, and ET4 represents the distance along the optical axis from the maximum effective aperture of the object side S7 of the fourth lens L4 to the maximum effective aperture of its image side S8.

[0119] (CT1+CT2+CT3) / SD32=0.969, where CT1 represents the distance of the first lens L1 on the optical axis, CT2 represents the distance of the second lens L2 on the optical axis, CT3 represents the distance of the third lens L3 on the optical axis, and SD32 represents the maximum effective half-aperture of the image side S6 of the third lens L3.

[0120] f4 / RS8 = -2.215, where f4 represents the effective focal length of the fourth lens L4, and RS8 represents the radius of curvature of the image-side surface S8 of the fourth lens L4 near the optical axis.

[0121] RS10 / f5 = 1.107, where f5 represents the effective focal length of the fifth lens L5, and RS10 represents the radius of curvature of the image-side surface S10 of the fifth lens L5 near the optical axis.

[0122] f6 / f5 = 1.643, where f5 represents the effective focal length of the fifth lens L5 and f6 represents the effective focal length of the sixth lens L6.

[0123] vd2-vd3=34.62, where vd2 represents the d-Abe number of the second lens L2 and vd3 represents the d-Abe number of the third lens L3.

[0124] RS6 / RS5 = 9.448, where RS5 represents the radius of curvature of the object side surface S5 of the third lens L3 near the optical axis, and RS6 represents the radius of curvature of the image side surface S6 of the third lens L3 near the optical axis.

[0125] f6*RS11=-5.718mm 2 Where f6 represents the effective focal length of the sixth lens L6, and RS11 represents the radius of curvature of the object side surface S11 of the sixth lens L6 near the optical axis.

[0126] Figure 2 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 100 of Embodiment 1 are shown respectively. The longitudinal spherical aberration curve shows the deflection of the focal point after light rays with wavelengths of 486.13 nm, 587.56 nm, and 656.27 nm pass through the optical system 100; the astigmatism curve shows the meridional (T) and sagittal (S) image plane curvature after light rays with a wavelength of 587.56 nm pass through the optical system 100; and the distortion curve shows the distortion at different image heights after light rays with a wavelength of 587.56 nm pass through the optical system 100. According to... Figure 2 As can be seen, the optical system 100 given in Example 1 can achieve good imaging quality.

[0127] Example 2

[0128] The following is for reference Figures 3 to 4 The optical system 100 of Embodiment 2 of this application is described. In this embodiment, for the sake of brevity, descriptions similar to those in Embodiment 1 are omitted.

[0129] Figure 3 A schematic diagram of the optical system 100 of Embodiment 2 is shown. Figure 3 As shown, the optical system 100 includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and an imaging plane S15.

[0130] The first lens L1 has positive refractive power. Its object-side surface S1 and image-side surface S2 are both aspherical. The object-side surface S1 is convex near the optical axis and convex near the circumference. The image-side surface S2 is concave near the optical axis and convex near the circumference.

[0131] The second lens L2 has negative refractive power. Its object-side surface S3 and image-side surface S4 are both aspherical. The object-side surface S3 is convex near the optical axis and convex near the circumference. The image-side surface S4 is concave near the optical axis and convex near the circumference.

[0132] The third lens L3 has negative refractive power. Its object-side surface S5 and image-side surface S6 are both aspherical. The object-side surface S5 is concave near the optical axis and concave near the circumference. The image-side surface S6 is convex near the optical axis and concave near the circumference.

[0133] The fourth lens L4 has positive refractive power. Its object-side surface S7 and image-side surface S8 are both aspherical. The object-side surface S7 is concave near the optical axis and concave near the circumference. The image-side surface S8 is convex near the optical axis and convex near the circumference.

[0134] The fifth lens L5 has negative refractive power. Its object-side surface S9 and image-side surface S10 are both aspherical. The object-side surface S9 is concave near the optical axis and concave near the circumference. The image-side surface S10 is concave near the optical axis and convex near the circumference.

[0135] The sixth lens L6 has negative refractive power. Its object-side surface S11 and image-side surface S12 are both aspherical. The object-side surface S11 is convex near the optical axis and convex near the circumference. The image-side surface S12 is concave near the optical axis and convex near the circumference.

[0136] The first lens L1 to the sixth lens L6 are all made of plastic. An aperture stop STO is also provided on the object side of the first lens L1 to limit the size of the incident beam and further improve the imaging quality of the optical system 100. The optical system 100 also includes a filter 110 disposed on the image side of the sixth lens L6, having an object side surface S13 and an image side surface S14. Light from the object OBJ passes sequentially through each surface S1 to S14 and is finally imaged on the imaging surface S15. Specifically, the filter 110 is an infrared cutoff filter made of glass.

[0137] Table 3 shows the surface type, radius of curvature, thickness, material, refractive index, Abbe number (i.e., dispersion coefficient), and effective focal length of each lens in the optical system 100 of Example 2. The reference wavelength for the effective focal length, refractive index, and Abbe number is 587.56 nm. The units for the radius of curvature, thickness, and effective focal length of each lens are millimeters (mm). Table 4 shows the higher-order coefficients that can be used for the aspherical surfaces S1-S12 of the lenses in Example 2. The aspherical surface shape can be defined by formula (1) given in Example 1.

[0138] Table 3

[0139]

[0140]

[0141] Table 4

[0142]

[0143] Figure 4 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 100 of Embodiment 2 are shown respectively. The longitudinal spherical aberration curve shows the deflection of the focal point after light rays with wavelengths of 486.13 nm, 587.56 nm, and 656.27 nm pass through the optical system 100; the astigmatism curve shows the meridional (T) and sagittal (S) image plane curvature after light rays with a wavelength of 587.56 nm pass through the optical system 100; and the distortion curve shows the distortion at different image heights after light rays with a wavelength of 587.56 nm pass through the optical system 100. According to... Figure 4 As can be seen, the optical system 100 given in Example 2 can achieve good imaging quality.

[0144] Example 3

[0145] The following is for reference Figures 5 to 6 The optical system 100 of Embodiment 3 of this application is described. In this embodiment, for the sake of brevity, descriptions similar to those in Embodiment 1 are omitted.

[0146] Figure 5 A schematic diagram of the optical system 100 of Embodiment 3 is shown. Figure 5 As shown, the optical system 100 includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and an imaging plane S15.

[0147] The first lens L1 has positive refractive power. Its object-side surface S1 and image-side surface S2 are both aspherical. The object-side surface S1 is convex near the optical axis and convex near the circumference. The image-side surface S2 is convex near the optical axis and convex near the circumference.

[0148] The second lens L2 has negative refractive power. Its object-side surface S3 and image-side surface S4 are both aspherical. The object-side surface S3 is convex near the optical axis and convex near the circumference. The image-side surface S4 is concave near the optical axis and convex near the circumference.

[0149] The third lens L3 has positive refractive power. Its object-side surface S5 and image-side surface S6 are both aspherical. The object-side surface S5 is concave near the optical axis and concave near the circumference. The image-side surface S6 is convex near the optical axis and concave near the circumference.

[0150] The fourth lens L4 has positive refractive power. Its object-side surface S7 and image-side surface S8 are both aspherical. The object-side surface S7 is concave near the optical axis and convex near the circumference. The image-side surface S8 is convex near the optical axis and convex near the circumference.

[0151] The fifth lens L5 has negative refractive power. Its object-side surface S9 and image-side surface S10 are both aspherical. The object-side surface S9 is concave near the optical axis and concave near the circumference. The image-side surface S10 is concave near the optical axis and convex near the circumference.

[0152] The sixth lens L6 has negative refractive power. Its object-side surface S11 and image-side surface S12 are both aspherical. The object-side surface S11 is convex near the optical axis and convex near the circumference. The image-side surface S12 is concave near the optical axis and convex near the circumference.

[0153] The first lens L1 to the sixth lens L6 are all made of plastic. An aperture stop STO is also provided on the object side of the first lens L1 to limit the size of the incident beam and further improve the imaging quality of the optical system 100. The optical system 100 also includes a filter 110 disposed on the image side of the sixth lens L6, having an object side surface S13 and an image side surface S14. Light from the object OBJ passes sequentially through each surface S1 to S14 and is finally imaged on the imaging surface S15. Specifically, the filter 110 is an infrared cutoff filter made of glass.

[0154] Table 5 shows the surface type, radius of curvature, thickness, material, refractive index, Abbe number (i.e., dispersion coefficient), and effective focal length of each lens in the optical system 100 of Example 3. The reference wavelength for the effective focal length, refractive index, and Abbe number is 587.56 nm, and the units for the radius of curvature, thickness, and effective focal length of each lens are millimeters (mm). Table 6 shows the higher-order coefficients that can be used for the aspherical surfaces S1-S12 of the lenses in Example 3, wherein the aspherical surface shape can be defined by formula (1) given in Example 1.

[0155] Table 5

[0156]

[0157]

[0158] Table 6

[0159]

[0160] Figure 6 The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 100 of Embodiment 3 are shown respectively. The longitudinal spherical aberration curve shows the deflection of the focal point after light rays with wavelengths of 486.13 nm, 587.56 nm, and 656.27 nm pass through the optical system 100; the astigmatism curve shows the meridional (T) and sagittal (S) image plane curvature after light rays with a wavelength of 587.56 nm pass through the optical system 100; and the distortion curve shows the distortion at different image heights after light rays with a wavelength of 587.56 nm pass through the optical system 100. According to... Figure 6 As can be seen, the optical system 100 given in Example 3 can achieve good imaging quality.

[0161] Example 4

[0162] The following is for reference Figures 7 to 8 The optical system 100 of Embodiment 4 of this application is described. In this embodiment, for the sake of brevity, descriptions similar to those in Embodiment 1 are omitted.

[0163] Figure 7 A schematic diagram of the optical system 100 of Embodiment 4 is shown. Figure 7 As shown, the optical system 100 includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and an imaging plane S15.

[0164] The first lens L1 has positive refractive power. Its object-side surface S1 and image-side surface S2 are both aspherical. The object-side surface S1 is convex near the optical axis and convex near the circumference. The image-side surface S2 is concave near the optical axis and convex near the circumference.

[0165] The second lens L2 has negative refractive power. Its object-side surface S3 and image-side surface S4 are both aspherical. The object-side surface S3 is convex near the optical axis and convex near the circumference. The image-side surface S4 is concave near the optical axis and concave near the circumference.

[0166] The third lens L3 has negative refractive power. Its object-side surface S5 and image-side surface S6 are both aspherical. The object-side surface S5 is concave near the optical axis and concave near the circumference. The image-side surface S6 is convex near the optical axis and convex near the circumference.

[0167] The fourth lens L4 has positive refractive power. Its object-side surface S7 and image-side surface S8 are both aspherical. The object-side surface S7 is concave near the optical axis and concave near the circumference. The image-side surface S8 is convex near the optical axis and convex near the circumference.

[0168] The fifth lens L5 has negative refractive power. Its object-side surface S9 and image-side surface S10 are both aspherical. The object-side surface S9 is concave near the optical axis and concave near the circumference. The image-side surface S10 is concave near the optical axis and convex near the circumference.

[0169] The sixth lens L6 has negative refractive power. Its object-side surface S11 and image-side surface S12 are both aspherical. The object-side surface S11 is convex near the optical axis and convex near the circumference. The image-side surface S12 is concave near the optical axis and convex near the circumference.

[0170] The first lens L1 to the sixth lens L6 are all made of plastic. An aperture stop STO is also provided on the object side of the first lens L1 to limit the size of the incident beam and further improve the imaging quality of the optical system 100. The optical system 100 also includes a filter 110 disposed on the image side of the sixth lens L6, having an object side surface S13 and an image side surface S14. Light from the object OBJ passes sequentially through each surface S1 to S14 and is finally imaged on the imaging surface S15. Specifically, the filter 110 is an infrared cutoff filter made of glass.

[0171] Table 7 shows the surface type, radius of curvature, thickness, material, refractive index, Abbe number (i.e., dispersion coefficient), and effective focal length of each lens in the optical system 100 of Example 4. The reference wavelength for the effective focal length, refractive index, and Abbe number is 587.56 nm, and the units for the radius of curvature, thickness, and effective focal length of each lens are millimeters (mm). Table 8 shows the higher-order coefficients that can be used for the aspherical surfaces S1-S12 of the lenses in Example 4, wherein the aspherical surface shape can be defined by formula (1) given in Example 1.

[0172] Table 7

[0173]

[0174]

[0175] Table 8

[0176]

[0177] Figure 8The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 100 of Embodiment 4 are shown respectively. The longitudinal spherical aberration curve shows the deflection of the focal point after light rays with wavelengths of 486.13 nm, 587.56 nm, and 656.27 nm pass through the optical system 100; the astigmatism curve shows the meridional (T) and sagittal (S) image plane curvature after light rays with a wavelength of 587.56 nm pass through the optical system 100; and the distortion curve shows the distortion at different image heights after light rays with a wavelength of 587.56 nm pass through the optical system 100. According to... Figure 8 As can be seen, the optical system 100 given in Example 4 can achieve good imaging quality.

[0178] Example 5

[0179] The following is for reference Figures 9 to 10 The optical system 100 of Embodiment 5 of this application is described. In this embodiment, for the sake of brevity, descriptions similar to those in Embodiment 1 are omitted.

[0180] Figure 9 A schematic diagram of the optical system 100 of Embodiment 5 is shown. Figure 9 As shown, the optical system 100 includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and an imaging plane S15.

[0181] The first lens L1 has positive refractive power. Its object-side surface S1 and image-side surface S2 are both aspherical. The object-side surface S1 is convex near the optical axis and convex near the circumference. The image-side surface S2 is concave near the optical axis and concave near the circumference.

[0182] The second lens L2 has negative refractive power. Its object-side surface S3 and image-side surface S4 are both aspherical. The object-side surface S3 is convex near the optical axis and convex near the circumference. The image-side surface S4 is concave near the optical axis and concave near the circumference.

[0183] The third lens L3 has positive refractive power. Its object-side surface S5 and image-side surface S6 are both aspherical. The object-side surface S5 is concave near the optical axis and concave near the circumference. The image-side surface S6 is convex near the optical axis and convex near the circumference.

[0184] The fourth lens L4 has positive refractive power. Its object-side surface S7 and image-side surface S8 are both aspherical. The object-side surface S7 is concave near the optical axis and concave near the circumference. The image-side surface S8 is convex near the optical axis and convex near the circumference.

[0185] The fifth lens L5 has negative refractive power. Its object-side surface S9 and image-side surface S10 are both aspherical. The object-side surface S9 is concave near the optical axis and concave near the circumference. The image-side surface S10 is concave near the optical axis and convex near the circumference.

[0186] The sixth lens L6 has negative refractive power. Its object-side surface S11 and image-side surface S12 are both aspherical. The object-side surface S11 is convex near the optical axis and convex near the circumference. The image-side surface S12 is concave near the optical axis and convex near the circumference.

[0187] The first lens L1 to the sixth lens L6 are all made of plastic. An aperture stop STO is also provided between the first lens L1 and the second lens L2 to limit the size of the incident beam and further improve the imaging quality of the optical system 100. The optical system 100 also includes a filter 110 disposed on the image side of the sixth lens L6, having an object side surface S13 and an image side surface S14. Light from the object OBJ passes sequentially through each surface S1 to S14 and is finally imaged on the imaging surface S15. Specifically, the filter 110 is an infrared cutoff filter made of glass.

[0188] Table 9 shows the surface type, radius of curvature, thickness, material, refractive index, Abbe number (i.e., dispersion coefficient), and effective focal length of each lens in the optical system 100 of Example 5. The reference wavelength for the effective focal length, refractive index, and Abbe number is 587.56 nm, and the units for the radius of curvature, thickness, and effective focal length of each lens are millimeters (mm). Table 10 shows the higher-order coefficients that can be used for the aspherical surfaces S1-S12 of the lenses in Example 5, wherein the aspherical surface type can be defined by formula (1) given in Example 1.

[0189] Table 9

[0190]

[0191]

[0192] Table 10

[0193]

[0194] Figure 10The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 100 of Embodiment 5 are shown respectively. The longitudinal spherical aberration curve shows the deflection of the focal point after light rays with wavelengths of 486.13 nm, 587.56 nm, and 656.27 nm pass through the optical system 100; the astigmatism curve shows the meridional (T) and sagittal (S) image plane curvature after light rays with a wavelength of 587.56 nm pass through the optical system 100; and the distortion curve shows the distortion at different image heights after light rays with a wavelength of 587.56 nm pass through the optical system 100. According to... Figure 10 As can be seen, the optical system 100 given in Example 5 can achieve good imaging quality.

[0195] Example 6

[0196] The following is for reference Figures 11 to 12 The optical system 100 of Embodiment 6 of this application is described. In this embodiment, for the sake of brevity, descriptions similar to those in Embodiment 1 are omitted.

[0197] Figure 11 A schematic diagram of the optical system 100 of Embodiment 6 is shown. Figure 11 As shown, the optical system 100 includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and an imaging plane S15.

[0198] The first lens L1 has positive refractive power. Its object-side surface S1 and image-side surface S2 are both aspherical. The object-side surface S1 is convex near the optical axis and convex near the circumference. The image-side surface S2 is concave near the optical axis and concave near the circumference.

[0199] The second lens L2 has negative refractive power. Its object-side surface S3 and image-side surface S4 are both aspherical. The object-side surface S3 is convex near the optical axis and convex near the circumference. The image-side surface S4 is concave near the optical axis and concave near the circumference.

[0200] The third lens L3 has positive refractive power. Its object-side surface S5 and image-side surface S6 are both aspherical. The object-side surface S5 is concave near the optical axis and concave near the circumference. The image-side surface S6 is convex near the optical axis and convex near the circumference.

[0201] The fourth lens L4 has positive refractive power. Its object-side surface S7 and image-side surface S8 are both aspherical. The object-side surface S7 is concave near the optical axis and concave near the circumference. The image-side surface S8 is convex near the optical axis and convex near the circumference.

[0202] The fifth lens L5 has negative refractive power. Its object-side surface S9 and image-side surface S10 are both aspherical. The object-side surface S9 is concave near the optical axis and concave near the circumference. The image-side surface S10 is concave near the optical axis and convex near the circumference.

[0203] The sixth lens L6 has negative refractive power. Its object-side surface S11 and image-side surface S12 are both aspherical. The object-side surface S11 is convex near the optical axis and convex near the circumference. The image-side surface S12 is concave near the optical axis and convex near the circumference.

[0204] The first lens L1 to the sixth lens L6 are all made of plastic. An aperture stop STO is also provided between the first lens L1 and the second lens L2 to limit the size of the incident beam and further improve the imaging quality of the optical system 100. The optical system 100 also includes a filter 110 disposed on the image side of the sixth lens L6, having an object side surface S13 and an image side surface S14. Light from the object OBJ passes sequentially through each surface S1 to S14 and is finally imaged on the imaging surface S15. Specifically, the filter 110 is an infrared cutoff filter made of glass.

[0205] Table 11 shows the surface type, radius of curvature, thickness, material, refractive index, Abbe number (i.e., dispersion coefficient), and effective focal length of each lens in the optical system 100 of Example 6. The reference wavelength for the effective focal length, refractive index, and Abbe number is 587.56 nm, and the units for the radius of curvature, thickness, and effective focal length of each lens are millimeters (mm). Table 12 shows the higher-order coefficients that can be used for the aspherical surfaces S1-S12 of the lenses in Example 6, wherein the aspherical surface shape can be defined by formula (1) given in Example 1.

[0206] Table 11

[0207]

[0208]

[0209] Table 12

[0210]

[0211] Figure 12The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system 100 of Embodiment 6 are shown respectively. The longitudinal spherical aberration curve shows the deflection of the focal point after light rays with wavelengths of 486.13 nm, 587.56 nm, and 656.27 nm pass through the optical system 100; the astigmatism curve shows the meridional (T) and sagittal (S) image plane curvature after light rays with a wavelength of 587.56 nm pass through the optical system 100; and the distortion curve shows the distortion at different image heights after light rays with a wavelength of 587.56 nm pass through the optical system 100. According to... Figure 12 As can be seen, the optical system 100 given in Example 6 can achieve good imaging quality.

[0212] Table 13 shows the numerical values ​​of the relevant relationships of the present invention for each of the above embodiments.

[0213] Table 13

[0214] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 f(mm) 2.87 2.88 2.88 2.75 2.66 2.67 FNO 2.2 2.2 2.2 2.2 2.2 2.4 HFOV(deg) 46 45.9 45.9 49.3 50.3 50 TTL(mm) 4.0 4.0 3.997 3.948 3.928 3.866 <![CDATA[tan(HFOV) / TTL(mm -1 )]]> 0.259 0.258 0.258 0.294 0.307 0.308 f2 / f1 -11.73 -3.23 -2.95 -3.34 -5.91 -5.36 ET4 / CT4 0.358 0.358 0.399 0.286 0.282 0.355 (CT1+CT2+CT3) / SD32 0.969 1.022 1.022 0.954 0.90 0.935 f4 / RS8 -2.215 -2.369 -2.59 -2.41 -2.548 -2.826 RS10 / f5 1.107 1.427 1.758 1.706 1.417 7.225 f6 / f5 1.643 1.207 1.075 1.113 1.665 0.761 vd2-vd3 34.62 2.37 2.37 4.26 18.18 13.47 RS6 / RS5 9.448 3.185 0.8 1.601 0.7 0.803 <![CDATA[f6*RS11(mm 2 )]]> -5.718 -5.649 -5.185 -6.22 -8.08 -7.206

[0215] like Figure 13 As shown, this application also provides an image-capturing module 200, including the optical system 100 as described above (e.g., Figure 1 (as shown); and a photosensitive element 210, which is disposed on the image side of the optical system 100, with the photosensitive surface of the photosensitive element 210 coinciding with the imaging surface S15. Specifically, the photosensitive element 210 can be a complementary metal-oxide-semiconductor (CMOS) image sensor or a charge-coupled device (CCD) image sensor. The imaging surface S15, depending on the corresponding photosensitive element 210, can be a plane or a curved surface with arbitrary curvature, especially a curved surface with a concave surface facing the object side.

[0216] In other embodiments, the image acquisition module 200 also includes a lens barrel (not shown) for carrying the optical system 100 and a corresponding support device (not shown).

[0217] In addition, the image acquisition module 200 also includes a driving device (not shown) and an image stabilization module (not shown). The driving device may have an auto-focus function, and its driving method can use a driving system such as a voice coil motor (VCM), microelectromechanical systems (MEMS), piezoelectric systems, or shape memory alloys. The driving device allows the optical system 100 to achieve a better imaging position, thus enabling clear images to be captured of the subject at different object distances. The image stabilization module can be an accelerometer, gyroscope, or Hall effect sensor. The drive unit, together with the image stabilization module, serves as an optical image stabilization (OIS) device. By adjusting the displacement of the optical system 100 on the optical axis, it compensates for the blurry image caused by shaking during shooting, or uses image compensation technology in the image software to provide electronic image stabilization (EIS), further improving the image quality of shooting in dynamic and low-light scenes.

[0218] The aforementioned image-capturing module 200, utilizing the aforementioned optical system 100, can capture images with a wide viewing angle and high quality. Simultaneously, the image-capturing module features a small head and short overall length, effectively improving the screen-to-body ratio. The image-capturing module 200 can be applied in mobile phones, automobiles, surveillance, medical fields, etc. Specifically, it can be used as a mobile phone camera, vehicle camera, surveillance camera, or endoscope, etc., possessing a broad market application range.

[0219] like Figure 14 As shown, this application also provides an electronic device 300, including a housing 310 and an image-capturing module 200 as described above, the image-capturing module 200 being mounted on the housing 310. Specifically, the image-capturing module 200 is disposed inside the housing 310 and exposed to the housing 310 to acquire images. The housing 310 can provide the image-capturing module 200 with dustproof, waterproof, and drop-proof protection. The housing 310 has holes corresponding to the image-capturing module 200 to allow light to pass through the holes into or out of the housing.

[0220] The aforementioned electronic device 300 is lightweight and, by utilizing the aforementioned image-capturing module 200, can achieve clear large-scene photography, thus enhancing the user's shooting experience. In other embodiments, the electronic device 300 is also equipped with a corresponding processing system, which can promptly transmit the image to the corresponding processing system after capturing the object image, so that the system can make accurate analysis and judgment.

[0221] In other embodiments, the "electronic device" used may also include, but is not limited to, devices configured to receive or transmit communication signals via a wired connection and / or via a wireless interface. Electronic devices configured to communicate via a wireless interface may be referred to as "wireless communication terminals," "wireless terminals," or "mobile terminals." Examples of mobile terminals include, but are not limited to, satellite or cellular phones; personal communication system (PCS) terminals that can combine cellular radiotelephones with data processing, fax, and data communication capabilities; personal digital assistants (PDAs) that may include radiotelephones, pagers, Internet / intranet access, web browsers, notebooks, calendars, and / or Global Positioning System (GPS) receivers; and conventional laptop and / or handheld receivers or other electronic devices that include radiotelephone transceivers. In addition, "electronic devices" may also include 3D image capture devices, digital cameras, tablet computers, smart TVs, network monitoring equipment, dashcams, reversing cameras, multi-lens devices, recognition systems, motion-sensing game consoles, and wearable devices, etc. The above-described electronic device is merely an illustrative example of the practical application of the present invention and is not intended to limit the scope of application of the imaging module of this application.

[0222] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0223] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An optical system characterized by, The optical system sequentially includes, along an optical axis from an object side to an image side: a first lens having positive refractive power, an object side surface of the first lens being convex at a vicinity of the optical axis; a second lens having negative refractive power, an object side surface of the second lens being convex at a vicinity of the optical axis, being convex at a vicinity of a periphery, an image side surface of the second lens being concave at a vicinity of the optical axis; a third lens having refractive power, an object side surface of the third lens being concave at a vicinity of the optical axis, an image side surface of the third lens being convex at a vicinity of the optical axis; a fourth lens having positive refractive power, an object side surface of the fourth lens being concave at a vicinity of the optical axis, an image side surface of the fourth lens being convex at a vicinity of the optical axis; a fifth lens having negative refractive power, an object side surface of the fifth lens being concave at a vicinity of the optical axis, being concave at a vicinity of a periphery, an image side surface of the fifth lens being concave at a vicinity of the optical axis, both the object side surface and the image side surface of the fifth lens being aspheric surfaces, and at least one of the object side surface and the image side surface of the fifth lens including at least one inflection point; and a sixth lens having negative refractive power, an object side surface of the sixth lens being convex at a vicinity of the optical axis, being convex at a vicinity of a periphery, an image side surface of the sixth lens being concave at a vicinity of the optical axis; The optical system satisfies the following relational expressions: 0.25mm -1 ≤ tan(HFOV) / TTL < 0.34mm -1 ; 0.5 < f6 / f5 < 2; wherein HFOV represents half of a maximum field angle of view of the optical system, TTL represents a distance on the optical axis from the object side surface of the first lens to an image plane of the optical system, f5 represents an effective focal length of the fifth lens, and f6 represents an effective focal length of the sixth lens.

2. The optical system of claim 1, wherein The optical system satisfies the following relational expressions: -13 < f2 / f1 < -1; wherein f1 represents an effective focal length of the first lens, and f2 represents an effective focal length of the second lens.

3. The optical system of claim 1, wherein The optical system satisfies the following relational expressions: 45 deg ≤ HFOV ≤ 51 deg; and TTL < 4.1 mm.

4. The optical system of claim 1, wherein The optical system satisfies the following relational expressions: 0.25 < ET4 / CT4 < 0.4; wherein CT4 represents a thickness of the fourth lens on the optical axis, and ET4 represents a distance in the direction of the optical axis from a maximum effective aperture of the object side surface of the fourth lens to a maximum effective aperture of the image side surface thereof.

5. The optical system of claim 1, wherein, The optical system satisfies the following relational expressions: 0.8 < (CT1+CT2+CT3) / SD32 < 1.1; wherein CT1 represents a thickness of the first lens on the optical axis, CT2 represents a thickness of the second lens on the optical axis, CT3 represents a thickness of the third lens on the optical axis, and SD32 represents a maximum effective half-aperture of the image side surface of the third lens.

6. The optical system of claim 1, wherein, The optical system satisfies the following relational expressions: -3 < f4 / RS8 < -2; wherein f4 represents an effective focal length of the fourth lens, and RS8 represents a radius of curvature of the image side surface of the fourth lens at the optical axis.

7. The optical system of claim 1, wherein The optical system satisfies the following relational expressions: 1 < vd2-vd3 < 40; wherein vd2 represents a d-line Abbe number of the second lens, and vd3 represents a d-line Abbe number of the third lens.

8. The optical system of claim 1, wherein, The optical system satisfies the following relational expressions: 0.5 < RS6 / RS5 < 10; wherein RS5 represents a radius of curvature of the object side surface of the third lens at the optical axis, and RS6 represents a radius of curvature of the image side surface of the third lens at the optical axis.

9. The optical system of claim 1, wherein, The optical system satisfies the following relationship: - 9.5 mm 2 <f6 RS11 < -4.5 mm 2 ; wherein f6 represents an effective focal length of the sixth lens, and RS11 represents a radius of curvature of the object side surface of the sixth lens at the optical axis.

10. An image capturing module, comprising: An image sensing module comprising the optical system according to any one of claims 1-9 and a photosensitive element disposed on the image side of the optical system.

11. An electronic device, comprising: An image sensing module comprising the optical system according to claim 10 and a housing, wherein the image sensing module is mounted on the housing.

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