CN118091895B - Optical lens - Google Patents

Abstract

The invention discloses an optical lens, which comprises a first lens with negative focal power, wherein the image side surface of the first lens is a concave surface; the second lens with negative focal power has a concave object side surface and a concave image side surface; a third lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a fourth lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a fifth lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a sixth lens element with positive refractive power having a concave object-side surface and a convex image-side surface at a paraxial region; a seventh lens element with negative refractive power having an object-side surface being convex at a paraxial region and an image-side surface being concave at a paraxial region; wherein, the fourth lens and the fifth lens form a cemented lens. The optical lens provided by the invention has the advantages of at least large field of view, large aperture, miniaturization and day-night confocal.

Description

Optical lens

Technical Field

The invention relates to the technical field of imaging lenses, in particular to an optical lens.

Background

With the development of intelligent automobiles, the driving assistance function of the automobiles is gradually enhanced, wherein the visual information acquisition is one of core tools. Meanwhile, with the improvement of the automatic driving level, the function requirement on the vehicle-mounted camera is gradually improved, wherein the vehicle-mounted camera comprises a monitoring lens in a vehicle. In-car monitoring lenses generally require the characteristics of large field of view, large aperture, day-night confocal, miniaturization and the like due to the special use environment, so as to realize high-definition imaging of in-car images and out-car images. However, the conventional in-vehicle monitoring lens has a small visual field range, cannot perform all-weather high-definition imaging, and cannot well meet the in-vehicle scene monitoring requirement.

Disclosure of Invention

Therefore, the invention aims to provide an optical lens which has at least the advantages of large field of view, large aperture, miniaturization and day-night confocal.

The invention provides an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: a first lens having negative optical power, the image side surface of which is concave; the second lens with negative focal power has a concave object side surface and a concave image side surface; a third lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a fourth lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a fifth lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a sixth lens element with positive refractive power having a concave object-side surface and a convex image-side surface at a paraxial region; a seventh lens element with negative refractive power having an object-side surface being convex at a paraxial region and an image-side surface being concave at a paraxial region; wherein, the fourth lens and the fifth lens form a cemented lens.

In some embodiments, the object side surface of the first lens is convex.

In some embodiments, the object-side surface of the first lens is concave at a paraxial region.

In some embodiments, the maximum field angle FOV of the optical lens satisfies: 155 ° < FOV <190 °.

In some embodiments, the optical total length TTL of the optical lens satisfies: 13mm < TTL <16mm.

In some embodiments, the effective focal length f of the optical lens satisfies: 1.5mm < f <3.5mm.

In some embodiments, the image height IH corresponding to the maximum field angle of the optical lens satisfies: 5.5mm < IH <8.0mm.

In some embodiments, the aperture value FNO of the optical lens satisfies: FNO <2.2.

In some embodiments, the optical total length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6.5< TTL/f <7.8.

In some embodiments, the total optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.0< TTL/IH <2.6.

In some embodiments, the effective focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -4.0< f1/f < -2.0.

In some embodiments, the effective focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -2.0< f4/f < -0.5.

In some embodiments, the effective focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.5< f5/f <1.1.

In some embodiments, the radius of curvature R8 of the object-side surface of the fifth lens and the radius of curvature R9 of the image-side surface of the fifth lens satisfy: -0.5< R8/R9< -0.05.

In some embodiments, the effective focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.0< f6/f <3.0; the radius of curvature R10 of the object side surface of the sixth lens and the radius of curvature R11 of the image side surface of the sixth lens satisfy: 0.8< (R10+R11)/(R10-R11) <2.0.

In some embodiments, the radius of curvature R3 of the object-side surface of the second lens and the radius of curvature R4 of the image-side surface of the second lens satisfy: -2.0< R3/R4<0; the curvature radius R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: -3.0< R3/f < -1.0.

In some embodiments, the radius of curvature R10 of the object-side surface of the sixth lens and the radius of curvature R11 of the image-side surface of the sixth lens satisfy: 2.0< R10/R11<30; the radius of curvature R10 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -30< R10/f < -1.0.

In some embodiments, the effective focal length f4 of the fourth lens and the effective focal length f5 of the fifth lens satisfy: -1.8< f4/f5< -0.7; the combined focal length f45 of the fourth lens and the fifth lens and the effective focal length f of the optical lens satisfy: 1.0< f45/f <20.

In some embodiments, the effective focal length f of the optical lens, the maximum field angle FOV of the optical lens, and the image height IH corresponding to the maximum field angle of the optical lens satisfy: 55 ° < (f×fov)/IH <65 °.

In some embodiments, the image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.5< IH/f <3.5.

In some embodiments, the effective focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -4.0< f2/f < -1.0.

In some embodiments, the effective focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.0< f3/f <3.0.

In some embodiments, the effective focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -3.0< f7/f < -1.0; the radius of curvature R12 of the object-side surface of the seventh lens and the radius of curvature R13 of the image-side surface of the seventh lens satisfy: 1.0< R12/R13<25.

In some embodiments, a stop is disposed between the second lens and the third lens.

In some embodiments, a stop is disposed between the third lens and the fourth lens.

In some embodiments, a filter is disposed between the seventh lens and the imaging surface.

In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are plastic lenses.

In some embodiments, at least one of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens is an aspherical lens.

Compared with the prior art, the optical lens provided by the invention adopts seven lenses, and can effectively converge a large range of light rays through specific surface shape arrangement and reasonable focal power distribution, so that the angle of view and the shooting range of the optical lens are improved; meanwhile, by reasonably setting the position of the diaphragm, the optical lens has a large aperture characteristic, the light incoming quantity of the optical lens can be effectively improved, and the day-night confocal performance of the optical lens is realized, so that the optical lens can perform high-definition imaging in a dim environment and all weather, the identification accuracy of scenes in a vehicle is improved, and the driving safety of a driver is ensured; in addition, through reasonable setting of the thickness of each lens, the interval between each lens and the optical back focus, the optical lens structure is more compact, and the miniaturization of the optical lens is facilitated.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic structural diagram of an optical lens according to a first embodiment of the present invention.

Fig. 2 is a graph showing a field curvature of an optical lens according to a first embodiment of the present invention.

Fig. 3 is an f-theta distortion graph of an optical lens according to a first embodiment of the present invention.

Fig. 4 is an axial aberration diagram of an optical lens according to a first embodiment of the present invention.

Fig. 5 is a vertical axis chromatic aberration diagram of an optical lens according to a first embodiment of the present invention.

Fig. 6 is a schematic structural diagram of an optical lens according to a second embodiment of the present invention.

Fig. 7 is a field curvature chart of an optical lens according to a second embodiment of the present invention.

Fig. 8 is an f-theta distortion graph of an optical lens according to a second embodiment of the present invention.

Fig. 9 is an axial aberration diagram of an optical lens according to a second embodiment of the present invention.

Fig. 10 is a vertical axis chromatic aberration diagram of an optical lens according to a second embodiment of the present invention.

Fig. 11 is a schematic structural diagram of an optical lens according to a third embodiment of the present invention.

Fig. 12 is a field curve diagram of an optical lens according to a third embodiment of the present invention.

Fig. 13 is an f-theta distortion graph of an optical lens according to a third embodiment of the present invention.

Fig. 14 is an axial aberration diagram of an optical lens according to a third embodiment of the present invention.

Fig. 15 is a vertical axis chromatic aberration diagram of an optical lens according to a third embodiment of the present invention.

Detailed Description

For a better understanding of the invention, various aspects of the invention will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed description are merely illustrative of embodiments of the invention and are not intended to limit the scope of the invention in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in the present specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the feature. Accordingly, a first lens discussed below may also be referred to as a second lens or a third lens without departing from the teachings of the present invention.

In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. In particular, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The figures are merely examples and are not drawn to scale.

Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, then the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side of the lens, and the surface of each lens closest to the imaging plane is referred to as the image side of the lens.

It will be further understood that the terms "comprises," "comprising," "includes," "including," "having," "containing," and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Furthermore, when a statement such as "at least one of the following" appears after a list of features that are listed, the entire listed feature is modified instead of modifying a separate element in the list. Furthermore, when describing embodiments of the invention, use of "may" means "one or more embodiments of the invention. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including 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 belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.

The invention provides an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are arranged on the same straight line, and the optical centers of the lenses are positioned on the same straight line.

In some embodiments, the first lens element is configured to have negative focal power, and the object-side surface is convex or concave at a paraxial region, and the image-side surface is concave, so that as many incident light rays with a large angle can be obtained as possible, the field angle of the optical lens element is enlarged, the turning trend of the light rays can be slowed down, the difficulty in correcting aberration of the rear optical system is reduced, and the imaging quality of the optical lens element is improved.

In some embodiments, the second lens element has a negative focal power, and the object-side surface is concave, and the image-side surface is concave, so that the light passing through the first lens element can be further diverged to expand the angle of view of the optical lens element, and meanwhile, the turning trend of the light can be slowed down to make the transition smooth, the sensitivity of the optical system is reduced, and the imaging quality of the optical lens element is improved.

In some embodiments, the third lens element has positive optical power, and the object-side surface is convex, and the image-side surface is convex, so that light passing through the second lens element can be converged and adjusted, the turning trend of the light is slowed down, the light is smoothly transited, the distortion of the marginal field of view is reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the fourth lens element has negative focal power, and the object-side surface is convex, and the image-side surface is concave, so that light rays can be further converged and smoothly transition, various aberrations generated by the front optical system can be balanced, and the imaging quality of the optical lens element can be improved.

In some embodiments, the fifth lens element has positive refractive power, and the object-side surface and the image-side surface of the fifth lens element are convex, so that the light beam passing through the fourth lens element can be rapidly adjusted to reduce light energy loss, and the relative illuminance of the light beam on the imaging surface can be improved, and meanwhile, the turning trend of the light beam can be slowed down to make the transition smooth, the sensitivity of the optical system is reduced, and the imaging quality of the optical lens element is improved.

In some embodiments, the fourth lens and the fifth lens form a cemented lens for sharing chromatic aberration correction of the optical lens and correcting various aberrations brought by the front optical system, so as to improve imaging quality of the optical lens, reduce light energy loss, improve relative illuminance and imaging definition of light on an imaging surface, and make the structure of the optical lens more compact, thereby being beneficial to realizing miniaturization of the optical lens.

In some embodiments, the sixth lens element has positive refractive power, and the object-side surface is concave at a paraxial region and the image-side surface is convex, so that light rays exiting from the front optical system can be converged to adjust the light ray directions of the central view field and the peripheral view field, and the imaging range and the imaging definition of the light rays on the imaging surface are improved.

In some embodiments, the seventh lens element has a negative refractive power, and the object-side surface is convex at a paraxial region and the image-side surface is concave at a paraxial region, so that an angle of incidence of the marginal field of view on the imaging surface can be effectively suppressed, and more light can be effectively transmitted to the imaging surface to clearly image the light on the imaging surface.

In some embodiments, the diaphragm may be disposed between the second lens and the third lens, or between the third lens and the fourth lens, so that light entering the optical system is effectively converged, and the power distribution of the front lens and the rear lens of the diaphragm may be balanced, so as to ensure the uniformity of the incident angle of the light of the front lens and the rear lens, and simultaneously reduce the aperture of the rear end of the optical system, reduce the sensitivity of the lens, and improve the stability of the optical lens.

In some embodiments, the optical lens may further include an optical filter disposed between the seventh lens and the imaging surface, for filtering the interference light, and preventing the interference light from reaching the imaging surface of the optical lens to affect normal imaging; meanwhile, the optical filter can be compatible with the visible light wave band and the infrared light wave band to pass through, so that the optical lens can perform high-definition imaging under the visible light and infrared light sources, the day-night confocal characteristic of the optical lens is realized, the optical lens can perform high-definition imaging under all weather, the identification accuracy of the scene in the vehicle is improved, and the driving safety of a driver is ensured.

In some implementations, the maximum field angle FOV of the optical lens satisfies: 155 ° < FOV <190 °. The wide-angle characteristic is beneficial to realizing the wide-angle characteristic by meeting the range, so that more scene information can be acquired, and the requirement of large-range shooting is met.

In some embodiments, the aperture value FNO of the optical lens satisfies: FNO <2.2. The optical lens meets the range, is favorable for realizing the characteristic of a large aperture, particularly reduces the noise influence caused by too weak light when the optical lens images in a dark environment, and further improves the imaging quality of the optical lens, so that the optical lens can meet the imaging requirements under different luminous fluxes and realize the characteristic of the large aperture and day-night confocal.

In some embodiments, the optical total length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6.5< TTL/f <7.8. The length of the optical lens can be effectively limited by meeting the above range, which is beneficial to realizing the miniaturization of the optical lens.

In some embodiments, the total optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.0< TTL/IH <2.6. The optical lens has the advantages that the ratio of the total length to the image height of the optical lens is reasonably limited, the optical total length can be shortened while the imaging of the large target surface of the optical lens is realized, the miniaturization of the optical lens and the equalization of the imaging of the large target surface can be realized, and the market competitiveness is improved.

In some embodiments, the effective focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -4.0< f1/f < -2.0. The optical lens has the advantages that the range is met, the negative refractive power of the first lens is reasonably set, light entering the first lens can be well converged and enter the optical system, the large view field is realized, meanwhile, the correction difficulty of aberration is reduced, and therefore the imaging quality of the optical lens can be well guaranteed.

In some embodiments, the effective focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -2.0< f4/f < -0.5. The above range is satisfied, and the convergence degree of the incident light can be effectively slowed down by reasonably controlling the focal length of the fourth lens, so that the large target surface imaging of the optical lens is facilitated.

In some embodiments, the effective focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.5< f5/f <1.1. The range is met, the focal length of the fifth lens is reasonably controlled, smooth transition of light is facilitated, various aberrations of the optical lens are corrected, and imaging quality of the optical lens is improved.

In some embodiments, the radius of curvature R8 of the object-side surface of the fifth lens and the radius of curvature R9 of the image-side surface of the fifth lens satisfy: -0.5< R8/R9< -0.05. The optical lens has the advantages that the range is met, the biconvex shape of the fifth lens is reasonably arranged, chromatic aberration of an optical system can be effectively corrected by being matched with the fourth lens, and the overall imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.0< f6/f <3.0; the radius of curvature R10 of the object side surface of the sixth lens and the radius of curvature R11 of the image side surface of the sixth lens satisfy: 0.8< (R10+R11)/(R10-R11) <2.0. The range is satisfied, and the focal length and the surface shape of the sixth lens are reasonably set, so that the aberration of the marginal view field can be effectively improved, and the overall imaging quality of the optical lens is improved.

In some embodiments, the radius of curvature R3 of the object-side surface of the second lens and the radius of curvature R4 of the image-side surface of the second lens satisfy: -2.0< R3/R4<0; the curvature radius R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy the following conditions: -3.0< R3/f < -1.0. The range is met, and through reasonably setting the biconcave surface type of the second lens, as many large-view-field light rays as possible can be collected, the view angle of the optical lens is further enlarged, meanwhile, the light rays can smoothly enter the rear optical system, and the imaging quality of the optical lens is ensured.

In some embodiments, the radius of curvature R10 of the object-side surface of the sixth lens and the radius of curvature R11 of the image-side surface of the sixth lens satisfy: 2.0< R10/R11<30; the radius of curvature R10 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -30< R10/f < -1.0. The range is satisfied, the generation of stray light can be effectively reduced by reasonably setting the concave-convex surface type of the sixth lens, meanwhile, the aberration of the marginal view field can be effectively improved, and the overall imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f4 of the fourth lens and the effective focal length f5 of the fifth lens satisfy: -1.8< f4/f5< -0.7; the combined focal length f45 of the fourth lens and the fifth lens and the effective focal length f of the optical lens satisfy: 1.0< f45/f <20. The range is satisfied, and through reasonably setting the focal length relation of the double-cemented lens, chromatic aberration of the optical system can be effectively corrected, imaging quality of the optical lens is improved, image quality of the optical system can be effectively improved, light energy loss is reduced, and imaging definition is increased.

In some embodiments, the effective focal length f of the optical lens, the maximum field angle FOV of the optical lens, and the image height IH corresponding to the maximum field angle of the optical lens satisfy: 55 ° < (f×fov)/IH <65 °. The optical lens has the advantages that the range is met, and the relationship among the focal length, the field angle and the image height of the optical lens is reasonably limited, so that the miniaturization of the optical lens and the balance of large field angle and large target surface imaging are facilitated.

In some embodiments, the image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.5< IH/f <3.5. The range is satisfied, so that the optical lens has the characteristic of larger image surface, and the high-definition imaging quality of the optical lens can be better realized.

In some embodiments, the effective focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -4.0< f2/f < -1.0. Satisfy above-mentioned scope, through the focal length of reasonable setting second lens, can share the negative focal power of optical lens front end to be favorable to avoiding too big because of the light deflection that the focal power of first lens was too concentrated causes, reduce the correction degree of difficulty of aberration.

In some embodiments, the effective focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.0< f3/f <3.0. The optical lens meets the above range, can effectively converge light rays by reasonably setting the focal length of the third lens, reduces the difficulty of distortion correction of the edge view field, ensures that the optical lens has smaller distortion while realizing a large view angle, and improves the overall imaging quality of the optical lens.

In some embodiments, the effective focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -3.0< f7/f < -1.0; the radius of curvature R12 of the object side surface of the seventh lens and the radius of curvature R13 of the image side surface of the seventh lens satisfy: 1.0< R12/R13<25. The range is met, the focal length and the surface shape of the seventh lens are reasonably set, so that the incident angle of light entering an image surface is increased, the imaging area of the optical lens is further increased, and the large target surface imaging of the optical lens is realized.

As an embodiment, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens may be plastic lenses, or glass-plastic mixed lenses may be used, so that good imaging effects can be obtained. In the application, in order to further reduce the volume and weight of the optical lens, reduce the cost of the optical lens and improve the imaging quality of the optical lens, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all plastic lenses. Further, at least one of the object side surface or the image side surface of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element is aspheric. The aspherical lens is characterized in that: unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better radius of curvature characteristic, and has advantages of improving distortion aberration and improving astigmatic aberration. Preferably, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all plastic aspherical lenses.

The invention is further illustrated in the following examples. In various embodiments, the thickness, radius of curvature, and material selection portion of each lens in the optical lens may vary, and for specific differences, reference may be made to the parameter tables of the various embodiments. The following examples are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and any other changes, substitutions, combinations or simplifications that do not depart from the gist of the present invention are intended to be equivalent substitutes within the scope of the present invention.

In various embodiments of the present invention, when an aspherical lens is used as the lens, the surface shape of the aspherical lens satisfies the following equation:

；

where z is the distance sagittal height from the aspherical surface vertex when the aspherical surface is at a position of height h in the optical axis direction, c is the paraxial curvature of the surface, k is a quadric surface coefficient, and a _2i is an aspherical surface type coefficient of 2 i-th order.

First embodiment

Referring to fig. 1, a schematic structural diagram of an optical lens 100 according to a first embodiment of the present invention is shown, where the optical lens 100 includes, in order from an object side to an imaging surface S16 along an optical axis: the first lens L1, the second lens L2, the third lens L3, the stop ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the filter G1.

The first lens element L1 is a plastic aspheric lens with negative refractive power, wherein an object-side surface S1 of the first lens element is a convex surface, and an image-side surface S2 of the first lens element is a concave surface; the second lens element L2 with a concave object-side surface S3 and a concave image-side surface S4 is a plastic aspheric lens with negative focal power; the third lens element L3 is a plastic aspheric lens with positive refractive power, wherein an object-side surface S5 of the third lens element is a convex surface, and an image-side surface S6 of the third lens element is a convex surface; the fourth lens element L4 is a plastic aspheric lens with negative refractive power, wherein an object-side surface S7 of the fourth lens element is a convex surface, and an image-side surface of the fourth lens element is a concave surface; the fifth lens element L5 is a plastic aspheric lens with positive refractive power, the object-side surface of the fifth lens element is a convex surface, the image-side surface S9 of the fifth lens element is a convex surface, and the fourth lens element L4 and the fifth lens element L5 form a cemented lens, wherein the cemented surface is S8; the sixth lens element L6 with positive refractive power is a plastic aspheric lens, wherein an object-side surface S10 of the sixth lens element is concave at a paraxial region thereof, and an image-side surface S11 of the sixth lens element is convex; the seventh lens element L7 with a negative refractive power is a plastic aspheric lens, wherein an object-side surface S12 of the seventh lens element is convex at a paraxial region thereof, and an image-side surface S13 of the seventh lens element is concave at a paraxial region thereof; the object side surface S14 and the image side surface S15 of the filter G1 are both planes.

Specifically, the design parameters of each lens of the optical lens 100 provided in this embodiment are shown in table 1.

TABLE 1

The surface profile coefficients of the aspherical surfaces of the optical lens 100 in this embodiment are shown in table 2.

TABLE 2

Fig. 2 shows a field curve diagram of the optical lens 100 of the present embodiment, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, with the horizontal axis representing the amount of shift (in mm) and the vertical axis representing the angle of view (in degrees). As can be seen from the figure, the curvature of field of the meridional image plane and the sagittal image plane are controlled within ±0.15mm, indicating that the curvature of field of the optical lens 100 is well corrected.

Fig. 3 shows an f- θ distortion graph of the optical lens 100 of the present embodiment, which represents f- θ distortion at different field angles on the imaging plane, the horizontal axis represents distortion values (unit:%) and the vertical axis represents field angles (unit: °). As can be seen from the figure, the f- θ distortion value is controlled within ±1.2%, indicating that the distortion of the optical lens 100 is well corrected.

Fig. 4 shows an axial aberration diagram of the optical lens 100 of the present embodiment, which represents aberration on the optical axis at the imaging plane, the horizontal axis represents the amount of shift (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the shortest wavelength and longest wavelength axial aberrations are controlled within ±0.025mm, indicating that the axial aberrations of the optical lens 100 are well corrected.

Fig. 5 shows a vertical axis color difference graph of the optical lens 100 of the present embodiment, which represents color differences of each wavelength at different image heights on an image plane, the horizontal axis represents the amount of shift (unit: μm), and the vertical axis represents the normalized field angle. As can be seen from the figure, the vertical chromatic aberration of the shortest wavelength and the longest wavelength is controlled within ±5 μm, which means that the optical lens 100 can better correct chromatic aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Second embodiment

Referring to fig. 6, a schematic structural diagram of an optical lens 200 according to a second embodiment of the present invention is shown, and the optical lens 200 according to the present embodiment is substantially the same as the optical lens 100 according to the first embodiment, except that: the object side surface S1 of the first lens element is concave at a paraxial region, and parameters such as a radius of curvature of each lens element, a thickness of each lens element, and an aspherical coefficient of each lens element are different.

Specifically, the design parameters of each lens of the optical lens 200 provided in this embodiment are shown in table 3.

TABLE 3 Table 3

The surface profile coefficients of the aspherical surfaces of the optical lens 200 in this embodiment are shown in table 4.

TABLE 4 Table 4

Referring to fig. 7, 8, 9 and 10, a field curve graph, an f- θ distortion graph, an axial aberration graph and a vertical axis chromatic aberration graph of the optical lens 200 of the present embodiment are shown respectively. As can be seen from fig. 7, the curvature of field of the meridional image plane and the sagittal image plane are controlled within ±0.1mm, which means that the curvature of field of the optical lens 200 is well corrected; as can be seen from fig. 8, the f- θ distortion value is controlled within ±3%, indicating that the distortion of the optical lens 200 is well corrected; as can be seen from fig. 9, the shortest wavelength and longest wavelength axial aberrations are controlled within ±0.025mm, indicating that the axial aberrations of the optical lens 200 are well corrected; as can be seen from fig. 10, the vertical chromatic aberration of the shortest wavelength and the longest wavelength is controlled within ±5 μm, which indicates that the optical lens 200 can better correct chromatic aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Third embodiment

Referring to fig. 11, a schematic structural diagram of an optical lens 300 according to a third embodiment of the present invention is shown, and the optical lens 300 of the present embodiment is substantially the same as the optical lens 100 of the first embodiment, except that: the position of the diaphragm, the radius of curvature of each lens surface, the thickness of each lens, the aspherical coefficient of each lens, and other parameters are different.

Specifically, the design parameters of each lens of the optical lens 300 provided in this embodiment are shown in table 5.

TABLE 5

The surface profile coefficients of the aspherical surfaces of the optical lens 300 in this embodiment are shown in table 6.

TABLE 6

Referring to fig. 12, 13, 14 and 15, a field curve graph, an f- θ distortion graph, an axial aberration graph and a vertical axis chromatic aberration graph of the optical lens 300 of the present embodiment are shown respectively. As can be seen from fig. 12, the curvature of field of the meridional image plane and the sagittal image plane are controlled within ±0.1mm, which means that the curvature of field of the optical lens 300 is well corrected; as can be seen from fig. 13, the f- θ distortion value is controlled within ±4%, indicating that the distortion of the optical lens 300 is well corrected; as can be seen from fig. 14, the shortest wavelength and longest wavelength axial aberrations are controlled within ±0.02mm, indicating that the axial aberrations of the optical lens 300 are well corrected; as can be seen from fig. 15, the vertical chromatic aberration of the shortest wavelength and the longest wavelength is controlled within ±5 μm, which means that the optical lens 300 can better correct chromatic aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Referring to table 7, the optical characteristics of the optical lens provided in the above three embodiments respectively include a maximum field angle FOV, an optical total length TTL, an image height IH corresponding to the maximum field angle, an effective focal length f, an aperture value FNO, and a correlation value corresponding to each of the foregoing conditional expressions.

TABLE 7

In summary, in the optical lens of the embodiment of the invention, seven plastic aspherical lenses are adopted, and by reasonably distributing the focal power and the surface of each lens and reasonably setting the thickness of each lens and the distance between each lens, the large field of view (165 ° < FOV <185 °), large aperture (2.0 < fno < 2.1), miniaturization (14.5 mm < ttl <15.5 mm), small distortion (-4% < DIS < 4%), day and night confocal and high pixel balance of the optical lens can be better realized, so that the use requirement of the in-vehicle monitoring lens can be satisfied.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above examples merely represent a few embodiments of the present invention, which are described in more detail and are not to be construed as limiting the scope of the present invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of the invention should be assessed as that of the appended claims.

Claims (10)

1. An optical lens comprising seven lenses in total, in order from an object side to an imaging surface along an optical axis, comprising:

A first lens having negative optical power, an image side surface of the first lens being a concave surface;

A second lens with negative focal power, wherein the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a concave surface;

A third lens with positive focal power, wherein the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface;

a fourth lens with negative focal power, wherein the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a concave surface;

A fifth lens with positive focal power, wherein an object side surface of the fifth lens is a convex surface, and an image side surface of the fifth lens is a convex surface;

A sixth lens element with positive refractive power having a concave object-side surface at a paraxial region and a convex image-side surface;

A seventh lens having negative optical power, an object-side surface of the seventh lens being convex at a paraxial region and an image-side surface of the seventh lens being concave at the paraxial region;

Wherein the fourth lens and the fifth lens form a cemented lens; the optical total length TTL of the optical lens and the effective focal length f of the optical lens meet the following conditions: 6.5< TTL/f <7.8; the total optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.0< TTL/IH <2.6.

2. The optical lens of claim 1, wherein an effective focal length f1 of the first lens and an effective focal length f of the optical lens satisfy: -4.0< f1/f < -2.0.

3. The optical lens of claim 1, wherein an effective focal length f4 of the fourth lens and an effective focal length f of the optical lens satisfy: -2.0< f4/f < -0.5.

4. The optical lens of claim 1, wherein an effective focal length f5 of the fifth lens and an effective focal length f of the optical lens satisfy: 0.5< f5/f <1.1.

5. The optical lens of claim 1, wherein a radius of curvature R8 of an object-side surface of the fifth lens and a radius of curvature R9 of an image-side surface of the fifth lens satisfy: -0.5< R8/R9< -0.05.

6. The optical lens of claim 1, wherein an effective focal length f6 of the sixth lens and an effective focal length f of the optical lens satisfy: 1.0< f6/f <3.0; the radius of curvature R10 of the object side surface of the sixth lens and the radius of curvature R11 of the image side surface of the sixth lens satisfy: 0.8< (R10+R11)/(R10-R11) <2.0.

7. The optical lens of claim 1, wherein a radius of curvature R3 of an object side surface of the second lens and a radius of curvature R4 of an image side surface of the second lens satisfy: -2.0< R3/R4<0; the curvature radius R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: -3.0< R3/f < -1.0.

8. The optical lens of claim 1, wherein a radius of curvature R10 of an object side surface of the sixth lens and a radius of curvature R11 of an image side surface of the sixth lens satisfy: 2.0< R10/R11<30; the radius of curvature R10 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -30< R10/f < -1.0.

9. The optical lens of claim 1, wherein an effective focal length f4 of the fourth lens and an effective focal length f5 of the fifth lens satisfy: -1.8< f4/f5< -0.7; the combined focal length f45 of the fourth lens and the fifth lens and the effective focal length f of the optical lens satisfy: 1.0< f45/f <20.

10. The optical lens of claim 1, wherein an effective focal length f of the optical lens, a maximum field angle FOV of the optical lens, and an image height IH corresponding to the maximum field angle of the optical lens satisfy: 55 ° < (f×fov)/IH <65 °.