CN114089507B

CN114089507B - Optical lens, camera module and electronic equipment

Info

Publication number: CN114089507B
Application number: CN202210039703.XA
Authority: CN
Inventors: 刘彬彬; 邹海荣; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2022-01-14
Filing date: 2022-01-14
Publication date: 2022-05-20
Anticipated expiration: 2042-01-14
Also published as: CN114089507A

Abstract

The invention discloses an optical lens, a camera module and electronic equipment, wherein the optical lens comprises a first lens, a second lens, a third lens and a fourth lens which are arranged in sequence from an object side to an image side along an optical axis; the first lens element with negative refractive power has positive refractive power, the second, third and fourth lens elements with positive refractive power have convex and concave surfaces at paraxial region, respectively, and the object-side and image-side surfaces of the first lens element with convex and concave surfaces at paraxial region, respectively, and the object-side and image-side surfaces of the third lens element with convex and concave surfaces at paraxial region, respectively, and the object-side and image-side surfaces of the fourth lens element with convex surfaces at paraxial region, respectively, and satisfy the following relations: 2< SAG22/SAG42 <5 >, wherein SAG22 is the rise of the image side surface of the second lens, and SAG42 is the rise of the image side surface of the fourth lens, so that the optical lens can meet the requirement of miniaturization design and has better imaging quality.

Description

Optical lens, camera module and electronic equipment

Technical Field

The invention relates to the technical field of optical imaging, in particular to an optical lens, a camera module and electronic equipment.

Background

With the miniaturization and full-screen development of electronic products, electronic identification modes including capacitance, optical, ultrasonic and other electronic identification modes are adopted to meet the requirements of miniaturization and full screen of the electronic products. Among them, the mode of using the optical underscreen fingerprint identification module to carry out optical identification is popular because of the realization of underscreen identification and low cost. However, the lens of the optical underscreen fingerprint identification module in the related art has a large overall volume and occupies a large internal space of the mobile phone; in addition, the imaging resolution of the optical underscreen fingerprint identification in the related art is limited, which is not beneficial to improving the fingerprint identification precision.

Disclosure of Invention

The embodiment of the invention discloses an optical lens, a camera module and electronic equipment.

In order to achieve the above object, in a first aspect, the embodiments of the present invention disclose an optical lens, which includes four lenses, each of which includes a first lens, a second lens, a third lens, and a fourth lens, which are disposed in order from an object side to an image side along an optical axis;

the first lens element with negative refractive power has a convex object-side surface at a paraxial region thereof and a concave image-side surface at a paraxial region thereof;

the second lens element with positive refractive power has a convex object-side surface at paraxial region and a concave image-side surface at paraxial region;

the third lens element with positive refractive power has a convex object-side surface at a paraxial region thereof and a convex image-side surface at a paraxial region thereof;

the fourth lens element with positive refractive power has a convex object-side surface at a paraxial region thereof, and has a convex image-side surface at a paraxial region thereof;

the optical lens satisfies the following relation: the absolute value of SAG22/SAG42 is more than or equal to 2 and less than or equal to 5;

SAG22 is a distance in the optical axis direction from a maximum effective aperture of an image side surface of the second lens to an intersection point of the image side surface of the second lens and the optical axis, namely a saggital height of the image side surface of the second lens at the maximum effective aperture, and SAG42 is a distance in the optical axis direction from a maximum effective aperture of an image side surface of the fourth lens to an intersection point of the image side surface of the fourth lens and the optical axis, namely a saggital height of the image side surface of the fourth lens at the maximum effective aperture.

In the optical lens of the embodiment of the present application, since the first lens element of the optical lens has negative refractive power, and the object-side surface of the first lens element is convex at the optical axis and the image-side surface of the first lens element is concave at the optical axis, light rays incident into the first lens element at a larger angle can be collected, so as to increase the field angle of the optical lens, and meanwhile, the sufficient negative refractive power of the first lens element can ensure that the optical lens has a smaller aperture, which is convenient for increasing the screen occupation ratio; the second lens element with positive refractive power has a convex object-side surface at the optical axis and a concave image-side surface at the optical axis, so that aberration generated by the first lens element can be corrected, and large-angle light rays collected by the first lens element can be effectively converged; the third lens element has positive refractive power and a biconvex surface type, so that the light rays incident from the second lens element can be further converged, and meanwhile, the fourth lens element has positive refractive power and a biconvex surface type, so that the light rays incident from the third lens element can be further converged, and the large-angle light rays can be transmitted to an imaging surface at a smaller incident angle. In addition, the second lens element, the third lens element and the fourth lens element all have positive refractive power, so that aberration which is difficult to correct and is generated by the first lens element with positive refractive power and negative refractive power can be corrected, the edge aberration of the optical lens can be eliminated, and high-quality imaging can be realized; meanwhile, the reasonable collocation and the surface type design of the refractive power of each lens are beneficial to reducing the size of the optical lens, and the effective convergence of the central view field and the edge view field can be realized, so that the optical total length of the optical lens is compressed, and the miniaturization design of the optical lens is met. Because the optical lens meets the relational expression, the plane-type bending degree of the second lens and the fourth lens can be reasonably controlled by controlling the rise of the image side surface of the second lens and the rise of the image side surface of the fourth lens, so that the spherical aberration generated by the optical lens can be favorably balanced, and the integral imaging resolving power of the optical lens is further improved. The miniaturization design of the optical lens is met.

As an alternative implementation, in an embodiment of the first aspect of the present invention, the optical lens satisfies the following relation: less than or equal to 2 (R41-R42)/(R41+ R42) less than or equal to 3; and/or, the optical lens satisfies the relation: i (R21-R22)/(R21+ R22) I is less than or equal to 0.5; wherein R41 is a radius of curvature of an object-side surface of the fourth lens element at the optical axis, R42 is a radius of curvature of an image-side surface of the fourth lens element at the optical axis, R21 is a radius of curvature of an object-side surface of the second lens element at the optical axis, and R22 is a radius of curvature of an image-side surface of the second lens element at the optical axis. Because the fourth lens is used as the lens closest to the imaging surface, the incident angle of the light transmitted to the imaging surface and the final aberration correction before imaging are influenced, when the optical lens meets the relational expression, the final aberration before imaging of the optical lens can be effectively corrected by controlling the curvature radius of the object side surface and the image side surface of the fourth lens at the optical axis, and therefore the imaging quality of the optical lens is improved. Similarly, by controlling the curvature radius of the object side surface and the image side surface of the second lens at the optical axis, the primary aberration which is generated when light passes through the first lens and is difficult to correct can be effectively corrected, the correction pressure of each lens is reduced, the effect of effectively correcting each stage of aberration of the optical lens is realized, and the imaging quality of the optical lens is improved.

As an alternative implementation, in an embodiment of the first aspect of the present invention, the optical lens satisfies the following relation: the absolute value of f12/f34 is more than or equal to 2 and less than or equal to 5; wherein f12 is a combined focal length of the first and second lenses, and f34 is a combined focal length of the third and fourth lenses. Because the optical lens meets the relational expression, the proportion of the combined focal length of the first lens and the second lens to the combined focal length of the third lens and the fourth lens is reasonably configured, namely the focal power of the front end and the rear end of the optical lens is reasonably configured, and the first lens with negative refractive power is combined, so that the first lens can collect light rays with large angles, the second lens further converges the light rays with large angles, the third lens and the fourth lens can effectively balance and correct aberration generated by the first lens and effectively converge the light rays with a central field of view and a peripheral field of view, the compactness of the optical lens can be improved, and the miniaturization design of the optical lens is realized.

As an alternative implementation, in an embodiment of the first aspect of the present invention, the optical lens satisfies the following relation: the | f/f2| + | f/f4| is less than or equal to 0.9; wherein f is an effective focal length of the optical lens; f2 is the focal length of the second lens, and f4 is the focal length of the fourth lens. Because the optical lens meets the relational expression, the refractive power of the second lens and the refractive power of the fourth lens are reasonably configured, the large spherical aberration which is difficult to correct and is generated by the first lens can be balanced, the integral imaging resolving power of the optical lens is improved, the correction capability of the peripheral field aberration of the optical lens is enhanced, meanwhile, the reasonable focal power distribution of the second lens and the fourth lens is convenient for smooth folding of the central field and the peripheral field light, the optical total length of the optical lens can be compressed, and the miniaturization design of the optical lens is favorably realized.

As an alternative implementation, in an embodiment of the first aspect of the present invention, the optical lens satisfies the following relation: the | f4/SAG42| is less than or equal to 10; wherein f4 is the focal length of the fourth lens. Because the optical lens meets the relational expression, the refractive power and the surface type of the fourth lens can be reasonably controlled by reasonably controlling the ratio of the focal length of the fourth lens to the rise of the image side surface of the fourth lens, so that the fourth lens closest to the imaging surface can compress the incident angle of light transmitted to the imaging surface and finally correct the aberration before imaging, the chromatic aberration and the spherical aberration of the optical lens can be reduced, and the imaging quality is improved.

As an alternative implementation, in an embodiment of the first aspect of the present invention, the optical lens satisfies the following relation: the | f1/SAG12| is less than or equal to 5; wherein f1 is a focal length of the first lens, and SAG12 is a distance in the optical axis direction from a maximum effective aperture of the image-side surface of the first lens to an intersection point of the image-side surface of the first lens and the optical axis. Because the first lens is used as the lens closest to the object side, the deflection angle of the incident light can affect the transmission of the subsequent light, when the optical lens meets the above relational expression, the refractive power and the surface type of the first lens can be reasonably controlled by reasonably controlling the ratio of the focal length of the first lens to the rise of the image side surface of the first lens, the incident light with large angle can be effectively converged, the light with large angle can be effectively deflected, the stray light caused by ineffective deflection is reduced, the primary aberration which is difficult to correct and generated when the light passes through the first lens is avoided, the aberration correction pressure of the rear lens (namely the second lens to the fourth lens) is reduced, the chromatic aberration and the spherical aberration of the optical lens are favorably reduced, the imaging quality of the optical lens is improved, the focal power of each lens is favorably and reasonably distributed, the convergence capacity of the optical lens to the light is strengthened, and the size of the optical lens is favorably compressed, to achieve a compact design of the optical lens.

As an alternative implementation, in an embodiment of the first aspect of the present invention, the optical lens satisfies the following relation: (| SAG41| + | SAG42|)/CT4 is less than or equal to 1.5; SAG41 is a distance from a maximum effective aperture of an object-side surface of the fourth lens to an intersection point of the object-side surface of the fourth lens and the optical axis in the optical axis direction, and CT4 is a thickness of the fourth lens on the optical axis. The refractive power of the fourth lens element and the thickness of the fourth lens element in the optical axis direction can be reasonably controlled to ensure reasonable surface shape change of the fourth lens element and avoid over-thin or over-thick thickness of the fourth lens element, thereby facilitating the molding and assembly of the fourth lens element; moreover, the reasonable surface shape change enables the fourth lens element to have enough refractive power, so that the light converging capability of the fourth lens element can be improved, the incident angle of light on the imaging surface of the optical lens is reduced, and the design sensitivity of the optical lens is reduced.

As an alternative implementation, in an embodiment of the first aspect of the present invention, the optical lens satisfies the following relation: r42/f is more than or equal to 2 and less than or equal to 3.15; wherein R42 is a curvature radius of an image-side surface of the fourth lens element at the optical axis, and f is an effective focal length of the optical lens assembly. Because the optical lens meets the relational expression, the proportion of the curvature radius of the image side surface of the fourth lens and the effective focal length of the optical lens can be reasonably configured, so that the surface type complexity of the fourth lens can be reduced, the processing and forming difficulty of the fourth lens is further reduced, the gentle surface type change is favorable for inhibiting field curvature and distortion, and the imaging quality of the optical lens is improved. In addition, by controlling the ratio of the curvature radius of the image-side surface of the fourth lens element to the effective focal length of the optical lens, the control of the back focus of the optical lens is facilitated (the back focus refers to the minimum distance from the image-side surface of the fourth lens element to the imaging surface of the optical lens along the optical axis direction), the total length of the optical lens is prevented from being too long, and the miniaturization design of the optical lens is facilitated.

In a second aspect, the present invention discloses a camera module, which includes a photosensitive chip and the optical lens according to the first aspect, wherein the photosensitive chip is disposed on an image side of the optical lens. The camera module with the optical lens of the first aspect has all the technical effects of the optical lens of the first aspect, namely, the optical lens can effectively balance spherical aberration generated by the optical lens, and further improves the integral forming resolving power of the optical lens.

In a third aspect, the present invention discloses an electronic device, which includes the camera module set of the second aspect of the housing, and the camera module set is disposed on the housing. The electronic device having the camera module according to the second aspect also has all the technical effects of the optical lens according to the first aspect. That is, the optical lens of the electronic device can effectively balance the spherical aberration generated by the optical lens, so as to improve the overall resolving power of the optical lens, and in addition, the first lens with negative refractive power is matched with the second lens, the third lens and the fourth lens with positive refractive power, so that the correction of the peripheral field aberration of the optical lens is facilitated, meanwhile, the reasonable surface shapes of the lenses are bent, the smooth turning of light rays is facilitated, the size reduction of the optical lens is facilitated, and the miniaturization design of the optical lens is met.

Compared with the prior art, the embodiment of the invention has the beneficial effects that:

by adopting the optical lens, the camera module and the electronic device provided by the embodiment, because the optical lens meets 2< | SAG22/SAG42| <5, the plane-type curvature degree of the second lens and the fourth lens can be reasonably configured by controlling the rise of the image side surface of the second lens and the rise of the image side surface of the fourth lens, so that the spherical aberration generated by the optical lens can be balanced, and the integral imaging resolving power of the optical lens can be improved, in addition, the reasonable plane-type design of the second lens and the fourth lens ensures that the refractive powers of the lenses are reasonably distributed, the lenses with positive refractive power and negative refractive power can be matched to offset the aberration generated by each other, namely, the first lens with negative refractive power is matched with the second lens, the third lens and the fourth lens with positive refractive power, so that the marginal field aberration of the optical lens can be eliminated, and meanwhile, the reasonable plane-type curvature of the second lens and the fourth lens can be matched, and the smooth turning of light rays is facilitated, so that the size of the optical lens is reduced, and the miniaturization design of the optical lens is met.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an optical lens disclosed in the present application;

fig. 2 is a spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical lens disclosed in the first embodiment of the present application;

fig. 3 is a schematic structural diagram of an optical lens disclosed in the second embodiment of the present application;

fig. 4 is a light ray spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical lens disclosed in a second embodiment of the present application;

fig. 5 is a schematic structural diagram of an optical lens disclosed in the third embodiment of the present application;

fig. 6 is a light ray spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical lens disclosed in the third embodiment of the present application;

fig. 7 is a schematic structural diagram of an optical lens disclosed in a fourth embodiment of the present application;

fig. 8 is a spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical lens disclosed in the fourth embodiment of the present application;

fig. 9 is a schematic structural diagram of an optical lens disclosed in a fifth embodiment of the present application;

fig. 10 is a spherical aberration diagram, an astigmatism diagram and a distortion diagram of an optical lens disclosed in a fifth embodiment of the present application;

fig. 11 is a schematic structural diagram of the camera module disclosed in the present application;

fig. 12 is a schematic structural diagram of an electronic device disclosed in the present application.

Detailed Description

In the present invention, the terms "first", "second", and the like are mainly used for distinguishing different devices, elements or components (the specific types and configurations may be the same or different), and are not used for indicating or implying relative importance or number of the indicated devices, elements or components. "plurality" means two or more unless otherwise specified.

The technical solution of the present invention will be further described with reference to the following embodiments and the accompanying drawings.

Referring to fig. 1, the present application discloses an optical lens 100, wherein the optical lens 100 includes a substrate L5, a first lens element L1, a second lens element L2, a third lens element L3 and a fourth lens element L4, which are sequentially disposed along an optical axis o from an object side to an image side. During imaging, light rays enter the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 from the substrate L5 in sequence, and are finally imaged on the imaging surface 101 of the optical lens 100. The first lens element L1 has negative refractive power, and the second lens element L2, the third lens element L3 and the fourth lens element L4 all have positive refractive power.

Further, the object-side surface S1 of the first lens element L1 is convex at the paraxial region o, the image-side surface S2 of the first lens element L1 is concave at the paraxial region o, the object-side surface S3 of the second lens element L2 is convex at the paraxial region o, the image-side surface S4 of the second lens element L2 is concave at the paraxial region o, the object-side surface S5 and the image-side surface S6 of the third lens element L3 are both convex at the paraxial region o, and the object-side surface S7 and the image-side surface S8 of the fourth lens element L4 are both convex at the paraxial region o.

Because the first lens element L1 of the optical lens 100 has negative refractive power, the object-side surface S1 is convex at the optical axis o, and the image-side surface S2 is concave at the optical axis o, so as to collect light rays incident into the first lens element L1 at a larger angle, thereby increasing the field angle of the optical lens 100, and meanwhile, the sufficient negative refractive power of the first lens element L1 can ensure that the optical lens 100 has a smaller aperture, thereby facilitating the improvement of the screen occupation ratio; by providing the second lens element L2 with positive refractive power, the object-side surface S3 is convex at the optical axis o, and the image-side surface S4 is concave at the optical axis o, which is favorable for correcting the aberration generated by the first lens element L1 and effectively converging the large-angle light rays collected by the first lens element L1; the third lens element L3 has positive refractive power and a biconvex shape, which is beneficial to further converging the light incident from the second lens element L2, and reduces the correction pressure of the second lens element L2, so that the high-angle light is smoothly transmitted to the fourth lens element L4, and the fourth lens element L4 has positive refractive power and a biconvex shape, which is beneficial to further converging the light incident from the third lens element L3, so that the high-angle light is transmitted to the image plane 101 at a smaller incident angle. In addition, since the second lens element L2, the third lens element L3 and the fourth lens element L4 all have positive refractive power, it is beneficial to correct the aberration which is difficult to correct and is generated by the first lens element L1 with positive refractive power, so as to be beneficial to eliminating the peripheral field aberration of the optical lens 100, and further to realize high-quality imaging; meanwhile, the reasonable arrangement of the refractive power of each lens and the surface shape design are beneficial to reducing the size of the optical lens 100, so that the effective convergence of the central view field and the edge view field can be realized, the total optical length of the optical lens 100 is reduced, and the miniaturization design of the optical lens 100 is met.

Optionally, the object-side surface S7 and/or the image-side surface S8 of the fourth lens element L4 may be provided with a plurality of inflection points, so as to effectively suppress an angle at which light rays of an off-axis field of view are incident on the photo-sensor chip, improve response efficiency of the photo-sensor chip, and contribute to correcting peripheral distortion of an image and improving relative illumination, and further effectively correct astigmatism and aberration of the off-axis field of view, thereby facilitating correction of distortion and field curvature generated by the first lens element L1, the second lens element L2, and the third lens element L3, and being capable of achieving good correction of field curvature and distortion aberration of an edge field of a large-angle lens, so that the refractive power configuration near the imaging surface 101 is relatively uniform, and thus the imaging quality of the optical lens 100 can be improved.

Alternatively, the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 may be made of plastic or glass. When a plastic material is used, the production cost is low and the weight is light, which is beneficial to reducing the cost of the whole optical lens 100 and the whole weight of the optical lens 100. When the glass material is used, the lens is not easy to expand with heat and contract with cold due to the change of the environmental temperature, so that the imaging quality of the optical lens 100 is relatively stable.

In addition, it is understood that when the optical lens 100 is applied to an electronic device such as a smart phone or a smart tablet, the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 may be made of plastic, so as to reduce the overall weight of the optical lens 100.

Optionally, at least one surface of at least one of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 is an aspheric surface, and the aspheric surface design can reduce the processing difficulty of the lenses and facilitate control of the surface types of the lenses. Specifically, the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 may all be aspheric lenses.

Further, the substrate L5 is disposed between the object (i.e., the object plane of the optical lens) and the object side surface S1 of the first lens L1, and the material of the substrate L5 may be plastic, glass, or other transparent materials. By providing a light-transmissive substrate L5 between the subject and the first lens L1, the optical lens 100 can be applied to a camera module to realize fingerprint recognition under a screen. When using, user's finger is pressed on base plate L5, and the photosensitive element of the module of making a video recording gathers fingerprint image to carry out fingerprint identification.

In some embodiments, the optical lens 100 further includes a stop 102, and the stop 102 may be an aperture stop or a field stop, which may be disposed between the object side of the optical lens 100 and the object side S1 of the first lens L1. It is understood that, in other embodiments, the diaphragm 102 may also be disposed between two adjacent lenses, for example, between the second lens L2 and the third lens L3, and the disposed position of the diaphragm 102 may be adjusted according to practical situations, which is not specifically limited in this embodiment.

In some embodiments, the optical lens 100 further includes a filter L6, such as an ir cut filter, disposed between the image-side surface S8 of the fourth lens L4 and the image plane 101 of the optical lens 100, so as to filter out infrared light and allow visible light to pass through, thereby avoiding the problem of image distortion caused by infrared light passing through the optical lens.

Generally, the imaging surface 101 of the optical lens 100 coincides with the photosensitive surface of the photosensitive chip. It should be noted that in some embodiments, the optical lens 100 may match a photo-sensor chip having a rectangular photo-sensing surface, and the imaging surface 101 of the optical lens 100 coincides with the rectangular photo-sensing surface of the photo-sensor chip. At this time, the effective pixel area on the imaging surface 101 of the optical lens 100 has a horizontal direction, a vertical direction and a diagonal direction, in this application, the maximum field angle of the optical lens 100 may be understood as the maximum field angle in the diagonal direction of the optical lens 100, and the image height corresponding to the maximum field angle may be understood as a half of the length in the diagonal direction of the effective pixel area on the imaging surface 101 of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the following relationship: 2 ≦ SAG22/SAG42 ≦ 5, where SAG22 is a distance in the optical axis o direction from the maximum effective aperture of the image-side surface S4 of the second lens L2 to the intersection point of the image-side surface S4 of the second lens L2 and the optical axis o, that is, a rise of the image-side surface S4 of the second lens L2, and SAG42 is a distance in the optical axis o direction from the maximum effective aperture of the image-side surface S8 of the fourth lens L4 to the intersection point of the image-side surface S8 of the fourth lens L4 and the optical axis o, that is, a rise of the image-side surface S8 of the fourth lens L4. Because the optical lens 100 meets the requirement that the SAGs 22/42 is less than or equal to 2 and less than or equal to 5, the plane-type bending degrees of the second lens L2 and the fourth lens L4 can be reasonably configured by controlling the rise of the image side surface S4 of the second lens L2 and the rise of the image side surface S8 of the fourth lens L4, the spherical aberration generated by the optical lens 100 is favorably balanced, the integral imaging resolving power of the optical lens 100 is further improved, and the optical lens 100 has better imaging quality, meanwhile, the size of the optical lens 100 is favorably compressed, and the miniaturization design of the optical lens 100 is met. When | SAG22/SAG42| >5, the rise of the image-side surface S4 of the second lens L2 is too large, which results in that the second lens L2 occupies a large volume of the optical lens 100, which is not favorable for realizing the miniaturization design of the optical lens 100, and the arrangement of the rise of the image-side surface S4 of the second lens L2 and the rise of the image-side surface S8 of the fourth lens L4 is not reasonable enough, which is not favorable for correcting spherical aberration of the optical lens 100, and the resolving power of the optical lens 100 is small, which results in that the imaging quality of the optical lens 100 is not ideal enough. When | SAG22/SAG42| < 2, the rise of the image-side surface S8 of the fourth lens L4 is too large, which results in that the fourth lens L4 occupies a large volume of the optical lens 100, which is not favorable for realizing the miniaturized design of the optical lens 100, and the arrangement of the rise of the image-side surface S4 of the second lens L2 and the rise of the image-side surface S8 of the fourth lens L4 is not reasonable enough, which is not favorable for correcting spherical aberration of the optical lens 100, and the resolving power of the optical lens 100 is small, which results in that the imaging quality of the optical lens 100 is not ideal.

In some embodiments, the optical lens 100 satisfies the following relationship: less than or equal to 2 (R41-R42)/(R41+ R42) less than or equal to 3; and/or | (R21-R22)/(R21+ R22) | is less than or equal to 0.5; wherein, R41 is a curvature radius of the object-side surface S7 of the fourth lens element L4 along the optical axis o, R42 is a curvature radius of the image-side surface S8 of the fourth lens element L4 along the optical axis o, R21 is a curvature radius of the object-side surface S3 of the second lens element L2 along the optical axis o, and R22 is a curvature radius of the image-side surface S4 of the second lens element L2 along the optical axis o. Since the fourth lens element L4, which is the lens element closest to the image plane, affects the incident angle of the light beam transmitted to the image plane and the final aberration correction before imaging, when the optical lens 100 satisfies 2 ≦ (R41-R42)/(R41+ R42) | ≦ 3, the final aberration before imaging of the optical lens 100 can be effectively corrected by controlling the radii of curvature of the object-side surface S7 and the image-side surface S8 of the fourth lens element L4 at the optical axis o, thereby improving the imaging quality of the optical lens 100. When | (R41-R42)/(R41+ R42) | > 3 or | (R41-R42)/(R41+ R42) | < 2, the arrangement of the radii of curvature of the object-side surface S7 and the image-side surface S8 of the fourth lens L4 at the optical axis o is not reasonable enough, so that the aberration of the optical lens 100 cannot be corrected well, and the imaging quality of the optical lens 100 is not ideal. Because the optical lens 100 satisfies | (R21-R22)/(R21+ R22) | is not more than 0.5, by controlling the curvature radius of the object side surface S3 and the image side surface S4 of the second lens L2 at the optical axis o, primary aberration which is generated when light passes through the first lens L1 and is difficult to correct can be effectively corrected, the correction pressure of each lens is reduced, each stage of aberration of the optical lens 100 can be effectively corrected, and the imaging quality of the optical lens 100 is improved. When | (R21-R22)/(R21+ R22) | > 0.5, the arrangement of the radii of curvature of the object-side surface S3 and the image-side surface S4 of the second lens L2 at the optical axis o is not reasonable enough, so that the aberration of the optical lens 100 cannot be corrected well.

In some embodiments, the optical lens 100 satisfies the following relationship: and | f12/f34| is more than or equal to 2 and less than or equal to 5, wherein f12 is the combined focal length of the first lens L1 and the second lens L2, and f34 is the combined focal length of the third lens L3 and the fourth lens L4. Because the optical lens 100 meets the condition that | f12/f34| is more than or equal to 2 and less than or equal to 5, the proportion of the combined focal length of the first lens L1 and the second lens L2 to the combined focal length of the third lens L3 and the fourth lens L4 is reasonably configured, namely the focal power of the front end and the rear end of the optical lens is reasonably configured, and meanwhile, the first lens L1 with negative refractive power is combined, so that the first lens L1 can collect light rays with large angles, the second lens L2 further converges the light rays with large angles, and the third lens L3 and the fourth lens L4 can effectively balance and correct aberration generated by the first lens L1 and effectively converge light rays with a central field and edge, the compactness of the optical lens 100 can be improved, and the miniaturization design of the optical lens 100 can be realized. When | f12/f34| >5, the combined focal length of the first lens L1 and the second lens L2 is too large to converge the marginal light, and the volume of the optical lens 100 is large, which is not favorable to realize the miniaturization design of the optical lens 100. When | f12/f34| < 2, the combined focal length of the third lens L3 and the fourth lens L4 is too large, it is difficult to effectively balance and correct the aberration generated by the first lens L1, and the imaging quality of the optical lens 100 is not ideal.

In some embodiments, the optical lens 100 satisfies the following relationship: | f/f2| + | f/f4| is less than or equal to 0.9, wherein f is the effective focal length of the optical lens 100; f2 is the focal length of the second lens L2, and f4 is the focal length of the fourth lens L4. Because the optical lens 100 satisfies | f/f2| + | f/f4 is less than or equal to 0.9, by reasonably configuring the refractive powers of the second lens element L2 and the fourth lens element L4, the large spherical aberration which is difficult to correct and is generated by the first lens element L1 can be balanced, the imaging resolving power of the whole optical lens 100 is improved, the correction capability of the peripheral field aberration of the optical lens 100 is enhanced, meanwhile, the reasonable power distribution of the second lens element L2 and the fourth lens element L4 is convenient for smooth turning of the central field and the peripheral field light, so that the optical total length of the optical lens 100 can be compressed, and the miniaturization design of the optical lens 100 is facilitated. When | f/f2| + | f/f4| > 0.9, the focal length configurations of the second lens L2 and the fourth lens L4 are not reasonable enough, it is difficult to effectively balance the large spherical aberration generated by the first lens L1 and correct the peripheral field aberration of the optical lens 100, which results in the poor imaging quality of the optical lens 100 and is not favorable for realizing the miniaturized design of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the following relationship: the | f4/SAG42| is less than or equal to 10. Because the optical lens 100 satisfies the above relational expression, the ratio of the focal length of the fourth lens element L4 to the rise of the image-side surface S8 of the fourth lens element L4 is reasonably controlled, and the refractive power and the surface type of the fourth lens element L4 are reasonably controlled, so that the fourth lens element L4 closest to the image plane can compress the incident angle of the light transmitted to the image plane, and finally correct the aberration before imaging, thereby reducing the chromatic aberration and spherical aberration of the optical lens 100 and improving the image quality. When | f4/SAG42| > 10, the ratio of the focal length of the fourth lens L4 to the rise of the image side surface S8 of the fourth lens L4 is not reasonable enough, the arrangement of the fourth lens L4 is difficult to reduce the chromatic aberration and spherical aberration of the optical lens 100, and the imaging quality of the optical lens 100 is not ideal.

In some embodiments, the optical lens 100 satisfies the following relationship: and | f1/SAG12| ≦ 5, wherein f1 is the focal length of the first lens L1, and SAG12 is the distance in the optical axis direction from the maximum effective aperture of the image side surface of the first lens to the intersection point of the image side surface of the first lens and the optical axis, namely the rise of the image side surface of the first lens. Since the first lens element L1 is the lens element closest to the object side, the deflection angle of the incident light will affect the transmission of the subsequent light, when the optical lens 100 satisfies the above relationship, by reasonably controlling the ratio of the focal length of the first lens element L1 to the rise of the image-side surface S2 of the first lens element L1, the refractive power and the surface shape of the first lens element L1 can be reasonably controlled, so as to effectively converge the incident light with large angle, effectively deflect the light with large angle, reduce the stray light caused by ineffective deflection, avoid the primary aberration which is difficult to correct and is generated when the light passes through the first lens element L1, reduce the aberration correction pressure of the rear lens element (i.e. the second lens element L2 to the fourth lens element L4), which is beneficial to reducing the chromatic aberration and spherical aberration of the optical lens 100, thereby improving the imaging quality of the optical lens 100, and beneficial to reasonably distributing the focal powers of the respective lens elements, and enhancing the light converging capability of the optical lens 100, while facilitating a reduction in the size of the optical lens 100 to achieve a compact design of the optical lens 100. When | f1/SAG12| >5, the ratio of the focal length of the first lens L1 to the rise of the image-side surface S2 of the first lens L1 is not reasonable enough, it is difficult to reduce the chromatic aberration and spherical aberration of the optical lens 100, the imaging quality of the optical lens 100 is not ideal, and it is not favorable for reasonable distribution of the optical power, which is not favorable for realizing the miniaturization design of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the following relationship: (| SAG41| + | SAG42|)/CT4 ≦ 1.5, wherein SAG41 is a distance in the direction of the optical axis o from the maximum effective aperture of the object side surface S7 of the fourth lens L4 to the intersection point of the object side surface S7 of the fourth lens L4 and the optical axis o, namely the rise of the object side surface S7 of the fourth lens L4, and CT4 is the thickness of the fourth lens L4 on the optical axis o. The refractive power of the fourth lens element L4 and the thickness of the fourth lens element L4 in the direction of the optical axis o can be reasonably controlled to make the surface shape of the fourth lens element L4 change reasonably, and avoid the thickness of the fourth lens element L4 being too thin or too thick, so as to facilitate the molding and assembling of the fourth lens element, and the reasonable surface shape change makes the fourth lens element L4 have sufficient refractive power, thereby improving the light converging capability of the fourth lens element L4, reducing the incident angle of light on the image plane 101, and reducing the design sensitivity of the optical lens 100. When (| SAG41| + | SAG42|)/CT4 > 1.5, the thickness of the fourth lens L4 on the optical axis o is too thin, and the structural strength of the fourth lens L4 is insufficient, thereby affecting the structural strength and the service life of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the following relationship: 2 ≦ R42/f ≦ 3.15, where R42 is the radius of curvature of the image-side surface S8 of the fourth lens L4 at the optical axis o. Since the optical lens 100 satisfies the above relational expression, the ratio of the curvature radius of the image-side surface S8 of the fourth lens L4 to the effective focal length of the optical lens 100 can be reasonably configured, so that the complexity of the surface shape of the fourth lens L4 can be reduced, the difficulty of the processing and molding of the fourth lens L4 can be reduced, the gentle surface shape change is favorable for suppressing curvature of field and distortion, and the imaging quality of the optical lens 100 can be improved, and further, by controlling the ratio of the curvature radius of the image-side surface S8 of the fourth lens L4 to the effective focal length of the optical lens 100, the back focus of the optical lens 100 (the back focus is the minimum distance in the optical axis o direction from the image-side surface S8 of the fourth lens L4 to the imaging surface 101 of the optical lens 100) can be favorably controlled, the total length of the optical lens 100 can be prevented from being too long, and the optical lens 100 can be favorably designed in a miniaturized manner. When | R42/f | > 3.15, the curvature radius of the image-side surface S8 of the fourth lens L4 is too large, the processing sensitivity of the fourth lens L4 is large, and when | R42/f | < 2, the focal length of the optical lens 100 is too large, which is not favorable for realizing the miniaturization design of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the following relationship: and | f/f1| ≦ 0.7 of more than or equal to 0.5, wherein f1 is the focal length of the first lens L1. When the optical lens 100 satisfies the above relation, the ratio of the effective focal length of the optical lens 100 to the focal length of the first lens L1 can be reasonably controlled, so that the aberration generated by the large-angle light entering from the first lens L1 can be corrected, the imaging quality can be improved, in addition, the effective convergence of the light in the edge field can be realized, the compactness of the optical lens 100 can be ensured, and the miniaturized design of the optical lens 100 can satisfy the wide-angle design. When | f/f1| > 0.7, the effective focal length of the optical lens 100 is too large, which is not favorable for ensuring the compactness of the optical lens 100 and is difficult to meet the miniaturization design requirement of the optical lens 100. When | f/f1| < 0.5, the focal length of the first lens L1 is too large, which is not favorable for the subsequent lens to converge the light with large angle entering the first lens L1, and it is difficult to correct the aberration of the optical lens 100, which may result in an unsatisfactory imaging quality.

In some embodiments, the optical lens 100 satisfies the following relationship: FOV/FNO is not less than 50deg, wherein FOV is the maximum angle of view of optical lens 100, and FNO is the f-number of optical lens 100. Because the optical lens 100 satisfies the above relational expression, the optical lens 100 has a larger field angle, so that the information capture range of the optical lens 100 can be expanded, and meanwhile, the optical lens 100 also has a smaller f-number, so that the optical lens 100 can have sufficient light transmission amount, the brightness of the imaging surface of the optical lens 100 can be improved, the imaging definition can be improved, the photosensitive performance of the photosensitive chip can be improved, and particularly, a picture with good definition can be obtained when the optical lens 100 works in a dark light environment. When FOV/FNO < 50deg, the optical lens has a small f-number, so that the optical lens 100 can obtain a sufficient amount of incident light to ensure that a sufficient amount of information is available for analyzing the presentation picture.

In some embodiments, the optical lens 100 satisfies the following relationship: 0.5-0.8 (CT1+ CT4)/(CT2+ CT3), wherein CT1 is the thickness of the first lens L1 on the optical axis o, CT2 is the thickness of the second lens L2 on the optical axis o, CT3 is the thickness of the third lens L3 on the optical axis o, and CT4 is the thickness of the fourth lens L4 on the optical axis o. Because the optical lens 100 satisfies the above relational expression, the thicknesses of the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 can be effectively controlled, the size of the optical lens 100 can be reduced, the optical lens 100 can be miniaturized, and the risk of parasitic light ghost between two adjacent lenses can be reduced. When (CT1+ CT4)/(CT2+ CT3) > 0.8, the thicknesses of the first lens L1 and the second lens L2 are too thick, which is not favorable for realizing a miniaturized design of the optical lens 100. When (CT1+ CT4)/(CT2+ CT3) < 0.5, the thicknesses of the first lens L1 and the second lens L2 are too thin, the processing sensitivity is high, and the processing of the lenses is not facilitated.

In some embodiments, the optical lens 100 satisfies the following relationship: CT3/CT4 is more than or equal to 1. Because the optical lens 100 satisfies the above relation, the thicknesses of the third lens L3 and the fourth lens L4 can be reasonably distributed, the compactness of the optical lens 100 is maintained, the emergent angle of light can be effectively reduced, the overall performance of the optical lens 100 can be improved, the excessive emergent light angle can be inhibited, and the risk of generating stray light is reduced. When CT3/CT4 < 1, the thickness of the third lens L3 and the fourth lens L4 are not properly arranged, so that it is difficult to suppress stray light, and the imaging quality is not satisfactory.

In some embodiments, the optical lens 100 satisfies the following relationship: SP12/SP34 is more than or equal to 10, wherein SP12 is the clearance between the first lens L1 and the second lens L2 on the optical axis, and SP34 is the clearance between the third lens L3 and the fourth lens L4 on the optical axis o. Because the optical lens 100 satisfies the above relational expression, the ratio of the gap between the first lens L1 and the second lens L2 to the gap between the third lens L3 and the fourth lens L4 can be reasonably configured, which is beneficial to compressing the gap between the lenses, improving the compactness of the arrangement of the lenses, being beneficial to realizing the miniaturization design of the optical lens 100, and being beneficial to reducing the risk of parasitic light ghost image between two adjacent lenses. When SP12/SP34 < 10, the arrangement of the gap between the lenses is not reasonable enough, which is disadvantageous for realizing a compact design of the optical lens 100 and for reducing the risk of a ghost image between two adjacent lenses.

In some embodiments, the optical lens 100 satisfies the following relationship: and OBJ/Imgh >5, wherein OBJ is half of the height of an object plane, and Imgh is the radius of the maximum effective imaging circle of the optical lens 100. Because the optical lens 100 satisfies the above relation, it ensures a sufficient recognition range, for example, for a fingerprint recognition lens, it is beneficial to increase the contact area, thereby increasing the accuracy, effectiveness, and rapidity of recognition induction. When the OBJ/Imgh is less than or equal to 5, the identification range is small, the induction accuracy and effectiveness are insufficient, and the identification speed is slow.

In some embodiments, the optical lens 100 satisfies the following relationship: SD42/SD11 is less than or equal to 1, wherein SD42 is half of the maximum effective aperture of the image side surface S8 of the fourth lens L4, and SD11 is half of the maximum effective aperture of the object side surface S1 of the first lens L1. By reasonably configuring the maximum effective half aperture of the image-side surface S8 of the fourth lens element L4 and the object-side surface S1 of the first lens element L1, the deflection angle of the large-angle light entering the optical lens 100 from the first lens element L1 can be reduced, so that the large-angle light can smoothly exit the image plane at a small angle, which is beneficial to correcting aberration and can keep the size of the optical lens 100 reasonable. When SD42/SD11 > 1, the maximum effective aperture of the image-side surface S8 of the fourth lens element L4 is large, which is not favorable for smoothly emitting light to the image plane and correcting aberration, and the optical lens 100 has a large size, which is not favorable for realizing the miniaturization design of the optical lens 100.

The optical lens 100 of the present embodiment will be described in detail with reference to specific parameters.

First embodiment

As illustrated in fig. 1, the optical lens 100 includes a substrate L5, a first lens L1, a second lens L2, a stop 102, a third lens L3, and a fourth lens L4, which are disposed in order from the object side to the image side along an optical axis o. During imaging, light rays enter the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 from the substrate L5 in sequence, and are finally imaged on the imaging surface 101 of the optical lens 100.

For the refractive power, material and surface shape design of the first lens element L1, the second lens element L2, the third lens element L3 and the fourth lens element L4 at the paraxial region, reference may be made to the above detailed description, which is not repeated herein.

Further, the object-side surface S1 and the image-side surface S2 of the first lens element L1 are convex and concave, respectively, at the circumference. The object-side surface S3 and the image-side surface S4 of the second lens element L2 are convex and concave, respectively, at the circumference. The object-side surface S5 and the image-side surface S6 of the third lens element L3 are convex at their circumferences. The object-side surface S7 and the image-side surface S8 of the fourth lens element L4 are concave and convex, respectively, at the circumference.

Specifically, taking the effective focal length f =0.55mm of the optical lens 100, the f-number size FNO =1.38 of the optical lens 100, the maximum field angle FOV =122deg of the optical lens 100, and the total optical length TTL =5.89mm of the optical lens 100 as an example, other parameters of the optical lens 100 are given in table 1 below. The elements of the optical lens 100 from the object side to the image side along the optical axis o are arranged in the order of the elements from top to bottom in table 1. In the same lens, the surface with the smaller number of surfaces is the object side surface of the lens, and the surface with the larger number of surfaces is the image side surface of the lens, and as in the case of the surfaces 3 and 4, the object side surface S1 and the image side surface S2 of the first lens L1 correspond respectively. The Y radius in table 1 is the radius of curvature of the object-side or image-side surface of the respective surface number at the paraxial region o. The first value in the "thickness" parameter set of a lens is the thickness of the lens on the optical axis o, and the second value is the distance from the image-side surface to the back surface of the lens on the optical axis o. The numerical value of the stop 102 in the "thickness" parameter column is the distance on the optical axis o from the stop 102 to the vertex of the next surface (the vertex refers to the intersection point of the surface and the optical axis o), the direction from the object side S1 of the first lens L1 to the image side of the last lens is the positive direction of the optical axis o, when the value is negative, it indicates that the stop 102 is disposed on the image side of the vertex of the next surface, and if the thickness of the stop 102 is positive, the stop 102 is disposed on the object side of the vertex of the next surface. It is understood that the units of the radius Y, thickness, and focal length in table 1 are all mm. And the reference wavelength of the refractive index, abbe number, focal length of each lens in table 1 was 537 nm.

TABLE 1

In the first embodiment, the object-side surface and the image-side surface of each of the first lens L1 to the fourth lens L4 is aspheric, and the aspheric lenses have surface shapesxThe following aspheric surface formula may be used for definition, but is not limited to:

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis o direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is the inverse of the radius Y in table 1 above); k is the cone coefficient; ai is a correction coefficient corresponding to the high-order term of the ith aspheric term. Table 2 shows the high-order term coefficients A4, A6, A8, A10, A12, A14 and A16 which can be used for the respective aspherical mirrors S1-S8 in the first embodiment.

TABLE 2

Referring to fig. 2 (a), fig. 2 (a) shows a light spherical aberration curve diagram of the optical lens 100 in the first embodiment at wavelengths of 460nm and 537 nm. In fig. 2 (a), the abscissa in the X-axis direction represents the focus shift, and the ordinate in the Y-axis direction represents the normalized field of view. As can be seen from fig. 2 (a), the spherical aberration value of the optical lens 100 in the first embodiment is better, which illustrates that the imaging quality of the optical lens 100 in this embodiment is better.

Referring to fig. 2 (B), fig. 2 (B) is a diagram of astigmatism of light of the optical lens 100 in the first embodiment at a wavelength of 537 nm. Wherein the abscissa along the X-axis direction represents the focus offset and the ordinate along the Y-axis direction represents the image height in mm. The astigmatism curves represent the meridional image plane curvature T and the sagittal image plane curvature S, and it can be seen from (B) in fig. 2 that the astigmatism of the optical lens 100 is well compensated at this wavelength.

Referring to fig. 2 (C), fig. 2 (C) is a distortion curve diagram of the optical lens 100 in the first embodiment at a wavelength of 537 nm. Wherein the abscissa along the X-axis direction represents the focus offset and the ordinate along the Y-axis direction represents the image height in mm. As can be seen from (C) in fig. 2, the distortion of the optical lens 100 can be corrected at the wavelength 537 nm.

Second embodiment

Referring to fig. 3, the optical lens 100 includes a substrate L5, a first lens L1, a second lens L2, a stop 102, a third lens L3, and a fourth lens L4 disposed along an optical axis o in order from an object side to an image side. During imaging, light rays enter the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 from the substrate L5 in sequence, and are finally imaged on the imaging surface 101 of the optical lens 100.

For the materials of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4, reference may be made to the above detailed description, and details thereof are not repeated here.

Further, in the second embodiment, the surface shape of each lens at the circumference is the same as that of each lens at the circumference in the first embodiment.

In the second embodiment, the effective focal length f =0.533mm of the optical lens 100, the aperture size FNO =13.8 of the optical lens 100, the FOV =124.5deg of the field angle of the optical lens 100, and the total optical length TTL =5.95mm of the optical lens 100 are taken as examples.

Other parameters in the second embodiment are given in the following table 3, and the definitions of the parameters can be obtained from the description of the foregoing embodiments, which are not repeated herein. It is understood that the units of the radius Y, thickness, and focal length in table 3 are all mm. And the reference wavelength of the refractive index, abbe number, focal length of each lens in table 3 was 537 nm.

TABLE 3

In the second embodiment, table 4 gives the high-order term coefficients that can be used for each aspherical surface in the second embodiment, wherein each aspherical surface type can be defined by the formula given in the first embodiment.

TABLE 4

Referring to fig. 4, as can be seen from the light spherical aberration diagram (a) in fig. 4, the light astigmatism diagram (B) in fig. 4, and the distortion diagram (C) in fig. 4, the longitudinal spherical aberration, astigmatism, and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of this embodiment has good imaging quality. In addition, as for the wavelengths corresponding to the curves in fig. 4 (a), fig. 4 (B), and fig. 4 (C), reference may be made to the contents described in the first embodiment with respect to fig. 2 (a), fig. 2 (B), and fig. 2 (C), and details thereof are not repeated here.

Third embodiment

Referring to fig. 5, the optical lens 100 includes a substrate L5, a first lens L1, a second lens L2, a stop 102, a third lens L3, and a fourth lens L4 disposed along an optical axis o in order from an object side to an image side. During imaging, light rays enter the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 from the substrate L5 in sequence, and are finally imaged on the imaging surface 101 of the optical lens 100.

Further, in the third embodiment, the surface shape at the circumference of each lens is the same as that of each lens in the first embodiment.

In the third embodiment, the effective focal length f =0.536mm of the optical lens 100, the aperture size FNO =1.5 of the optical lens 100, the field angle FOV =126.7deg of the optical lens 100, and the total optical length TTL =6.29mm of the optical lens 100 are taken as examples.

Other parameters in the third embodiment are shown in the following table 5, and the definitions of the parameters can be obtained from the foregoing description, which is not repeated herein. It is understood that the units of the radius Y, thickness, and focal length in table 5 are mm. And the reference wavelength of the refractive index, Abbe number, focal length of each lens in Table 5 was 537 nm.

TABLE 5

In the third embodiment, table 6 gives the high-order term coefficients that can be used for each aspherical surface in the third embodiment, wherein each aspherical surface type can be defined by the formula given in the first embodiment.

TABLE 6

Referring to fig. 6, as can be seen from the light spherical aberration diagram (a) in fig. 6, the light astigmatism diagram (B) in fig. 6, and the distortion diagram (C) in fig. 6, the longitudinal spherical aberration, astigmatism, and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of this embodiment has good imaging quality. In addition, as for the wavelengths corresponding to the curves in fig. 6 (a), fig. 6 (B), and fig. 6 (C), reference may be made to the contents described in the first embodiment with respect to fig. 2 (a), fig. 2 (B), and fig. 2 (C), and details thereof are not repeated herein.

Fourth embodiment

Referring to fig. 7, the optical lens 100 includes a substrate L5, a first lens L1, a second lens L2, a stop 102, a third lens L3, and a fourth lens L4 disposed along an optical axis o in order from an object side to an image side. During imaging, light rays enter the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 from the substrate L5 in sequence, and are finally imaged on the imaging surface 101 of the optical lens 100.

Further, in the fourth embodiment, the surface shape of each lens at the circumference is the same as that of each lens at the circumference in the first embodiment.

In the fourth embodiment, the effective focal length f =0.535mm of the optical lens 100, the aperture size FNO =1.38 of the optical lens 100, the field angle FOV =127deg of the optical lens 100, and the total optical length TTL =5.58mm of the optical lens 100 are taken as examples.

Other parameters in the fourth embodiment are shown in the following table 7, and the definitions of the parameters can be obtained from the foregoing description, which is not repeated herein. It is understood that the units of the radius Y, thickness, and focal length in table 7 are mm. And the reference wavelength of the refractive index, Abbe number, focal length of each lens in Table 7 was 537 nm.

TABLE 7

In the fourth embodiment, table 8 gives the high-order term coefficients that can be used for each aspherical surface in the fourth embodiment, wherein each aspherical surface type can be defined by the formula given in the first embodiment.

TABLE 8

Referring to fig. 8, as can be seen from the light spherical aberration diagram (a) in fig. 8, the light astigmatism diagram (B) in fig. 8, and the distortion diagram (C) in fig. 8, the longitudinal spherical aberration, astigmatism, and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of this embodiment has good imaging quality. In addition, as for the wavelengths corresponding to the curves in fig. 8 (a), fig. 8 (B), and fig. 8 (C), the contents described in the first embodiment with respect to fig. 2 (a), fig. 2 (B), and fig. 2 (C) may be referred to, and details thereof are not repeated herein.

Fifth embodiment

Referring to fig. 9, the optical lens 100 includes a substrate L5, a first lens L1, a second lens L2, a stop 102, a third lens L3, and a fourth lens L4 disposed along an optical axis o in order from an object side to an image side. During imaging, light rays enter the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 from the substrate L5 in sequence, and are finally imaged on the imaging surface 101 of the optical lens 100.

Further, in the fifth embodiment, the surface shape of each lens at the circumference is the same as that of each lens at the circumference in the first embodiment.

In the fifth embodiment, the effective focal length f =0.527mm of the optical lens 100, the aperture size FNO =1.5 of the optical lens 100, the field angle FOV =125.4deg of the optical lens 100, and the total optical length TTL =6.4mm of the optical lens 100 are taken as examples.

The other parameters in the fifth embodiment are shown in the following table 9, and the definitions of the parameters can be obtained from the foregoing description, which is not repeated herein. It is understood that the units of the radius Y, thickness, and focal length in table 9 are mm. And the reference wavelength of the refractive index, Abbe number, focal length of each lens in Table 9 was 537 nm.

TABLE 9

In the fifth embodiment, table 10 gives the high-order term coefficients that can be used for each aspherical surface in the fifth embodiment, wherein each aspherical surface type can be defined by the formula given in the first embodiment.

Watch 10

Referring to fig. 10, as can be seen from the light spherical aberration diagram (a) in fig. 10, the light astigmatism diagram (B) in fig. 10, and the distortion diagram (C) in fig. 10, the longitudinal spherical aberration, astigmatism, and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of this embodiment has good imaging quality. In addition, as for the wavelengths corresponding to the curves in fig. 10 (a), fig. 10 (B), and fig. 10 (C), reference may be made to the contents described in the first embodiment with respect to fig. 2 (a), fig. 2 (B), and fig. 2 (C), and details thereof are not repeated herein.

Referring to table 11, table 11 summarizes ratios of the relations in the first embodiment to the fifth embodiment of the present application.

TABLE 11

Referring to fig. 11, the present application further discloses a camera module 200, which includes a photo sensor 201 and the optical lens 100 according to any of the first to fifth embodiments, wherein the photo sensor 201 is disposed at an image side of the optical lens 100. The optical lens 100 may be configured to receive a light signal of a subject and project the light signal to the light sensing chip 201, and the light sensing chip 201 may be configured to convert the light signal corresponding to the subject into an image signal. And will not be described in detail herein. It can be understood that the camera module 200 having the optical lens 100 has all the technical effects of the optical lens 100, that is, the optical lens 100 can effectively balance the spherical aberration generated by the optical lens 100, so as to improve the overall imaging resolution of the optical lens 100, and in addition, the first lens element L1 having negative refractive power is matched with the second lens element L2, the third lens element L3 and the fourth lens element L4 having positive refractive power, so as to facilitate eliminating the peripheral field aberration of the optical lens 100, and at the same time, facilitate reducing the size of the optical lens 100, and meet the requirement of miniaturization design of the optical lens. Since the above technical effects have been described in detail in the embodiments of the optical lens 100, they are not described herein again.

Referring to fig. 12, the present application further discloses an electronic device, where the electronic device 300 includes a housing 301 and the camera module 200 as described above, and the camera module 200 is disposed on the housing 301 to obtain image information. The electronic device 300 may be, but is not limited to, a mobile phone, a tablet computer, a notebook computer, a smart watch, a monitor, and the like. It can be understood that the electronic device 300 having the camera module 200 also has all the technical effects of the optical lens 100. That is, the optical lens 100 can effectively balance the spherical aberration generated by the optical lens 100, so as to improve the imaging resolution of the whole optical lens 100, and in addition, the first lens element L1 with negative refractive power is matched with the second lens element L2, the third lens element L3 and the fourth lens element L4 with positive refractive power, which is beneficial to eliminating the peripheral field aberration of the optical lens 100, and meanwhile, is beneficial to reducing the size of the optical lens 100, so as to meet the requirement of miniaturization design of the optical lens. Since the above technical effects have been described in detail in the embodiments of the optical lens 100, they are not described herein again.

The optical lens, the camera module and the electronic device disclosed in the embodiments of the present invention are described in detail above, and the principle and the embodiments of the present invention are explained in detail herein by applying specific examples, and the description of the embodiments above is only used to help understanding the optical lens, the camera module and the electronic device and the core ideas thereof; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. An optical lens is characterized in that the optical lens consists of four lenses, namely a first lens, a second lens, a third lens and a fourth lens which are arranged from an object side to an image side along an optical axis in sequence;

the optical lens satisfies the following relation:

2≤|SAG22/SAG42|≤5；

SAG22 is a distance in the optical axis direction from a maximum effective aperture of an image-side surface of the second lens to an intersection point of the image-side surface of the second lens and the optical axis, and SAG42 is a distance in the optical axis direction from a maximum effective aperture of an image-side surface of the fourth lens to an intersection point of the image-side surface of the fourth lens and the optical axis.

2. An optical lens according to claim 1, characterized in that the optical lens satisfies the following relation:

less than or equal to 2 (R41-R42)/(R41+ R42) less than or equal to 3; and/or the presence of a gas in the gas,

the optical lens satisfies the relation: i (R21-R22)/(R21+ R22) I is less than or equal to 0.5;

wherein R41 is a radius of curvature of an object-side surface of the fourth lens element at the optical axis, R42 is a radius of curvature of an image-side surface of the fourth lens element at the optical axis, R21 is a radius of curvature of an object-side surface of the second lens element at the optical axis, and R22 is a radius of curvature of an image-side surface of the second lens element at the optical axis.

3. An optical lens according to claim 1, wherein the optical lens satisfies the following relation:

2≤|f12/f34|≤5；

wherein f12 is a combined focal length of the first lens and the second lens, and f34 is a combined focal length of the third lens and the fourth lens.

4. An optical lens according to claim 1, wherein the optical lens satisfies the following relation:

|f/f2|+|f/f4|≤0.9；

wherein f is the effective focal length of the optical lens; f2 is the focal length of the second lens, and f4 is the focal length of the fourth lens.

5. An optical lens according to claim 1, wherein the optical lens satisfies the following relation:

|f4/SAG42|≤10；

wherein f4 is the focal length of the fourth lens.

6. An optical lens according to claim 1, wherein the optical lens satisfies the following relation:

|f1/SAG12|≤5；

wherein f1 is a focal length of the first lens, and SAG12 is a distance in the optical axis direction from a maximum effective aperture of the image-side surface of the first lens to an intersection point of the image-side surface of the first lens and the optical axis.

7. An optical lens according to claim 1, wherein the optical lens satisfies the following relation:

(|SAG41|+|SAG42|)/CT4≤1.5；

SAG41 is a distance from a maximum effective aperture of an object-side surface of the fourth lens to an intersection point of the object-side surface of the fourth lens and the optical axis in the optical axis direction, and CT4 is a thickness of the fourth lens on the optical axis.

8. An optical lens according to claim 1, wherein the optical lens satisfies the following relation:

2≤|R42/f|≤3.15；

wherein R42 is a curvature radius of an image-side surface of the fourth lens element at the optical axis, and f is an effective focal length of the optical lens assembly.

9. A camera module, comprising a photo sensor chip and the optical lens of any one of claims 1-8, wherein the photo sensor chip is disposed on an image side of the optical lens.

10. An electronic device, comprising a housing and the camera module of claim 9, wherein the camera module is disposed in the housing.