CN117784371A

CN117784371A - Optical lens

Info

Publication number: CN117784371A
Application number: CN202410204857.9A
Authority: CN
Inventors: 张力瑶; 章彬炜
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2024-02-26
Filing date: 2024-02-26
Publication date: 2024-03-29
Anticipated expiration: 2044-02-26
Also published as: CN117784371B

Abstract

The invention discloses an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: the first lens with negative focal power has a convex object side surface and a concave image side surface; a second lens having optical power; a third lens having positive optical power, the image side surface of which is convex; a diaphragm; a fourth lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a fifth lens having negative optical power; a sixth lens element with positive refractive power having a convex image-side surface; wherein, the image height IH corresponding to the maximum field angle of the optical lens and the f-number FNO of the optical lens satisfy: IH/FNO is less than 4.0mm and less than 4.7mm. The optical lens provided by the invention well realizes the balance of small size, large aperture, large image plane, large field angle and high pixel, can be used in indoor and outdoor monitoring scenes, and can better meet the future development trend of the monitoring lens.

Description

Optical lens

Technical Field

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

Background

With the continuous rapid development of social science and technology, more families tend to install monitoring lenses in the families, so that the families can be protected conveniently when going out for a long time, and the dynamic state of the old and children in the families can be concerned in real time through monitoring. With the popularization of the monitoring lens, the demand of people for the monitoring lens is continuously increased, and the people are not limited to the situation that the people can see the pictures, but a monitoring lens capable of meeting most of the use environments is more needed. Most monitoring lenses in the market at present are large in size, low in pixel, poor in shooting quality at night or in dark environments, or can only be used indoors, and basically, the imaging requirements of people on the monitoring lenses are hardly met.

Disclosure of Invention

Therefore, the present invention is directed to an optical lens having at least the advantages of high pixel, large aperture, and small size.

The invention provides an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: the first lens with negative focal power has a convex object side surface and a concave image side surface; a second lens having optical power; a third lens having positive optical power, the image side surface of which is convex; a diaphragm; a fourth lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a fifth lens having negative optical power; a sixth lens element with positive refractive power having a convex image-side surface; wherein, the image height IH corresponding to the maximum field angle of the optical lens and the f-number FNO of the optical lens satisfy: IH/FNO is less than 4.0mm and less than 4.7mm.

Compared with the prior art, the invention has the beneficial effects that: according to the optical lens provided by the invention, six lenses with specific refractive power are adopted, and through specific surface shape collocation and reasonable focal power distribution, the structure of the optical lens is more compact, the field angle can reach more than 110 degrees, meanwhile, the optical lens is provided with a large aperture and a large image surface, and ultra-high definition imaging can be realized by matching with a 1/2.7 inch large target surface imaging chip, so that the balance of small size, large aperture, large image surface, large field angle and high pixel of the optical lens is better realized, the use of indoor and outdoor monitoring scenes can be considered, and the future development trend of the monitoring lens can be better met.

Drawings

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

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

Fig. 3 is a graph showing a field curvature of an optical lens according to a first embodiment of the present invention.

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

Fig. 5 is an axial 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 distortion graph of an optical lens according to a second embodiment of the present invention.

Fig. 8 is a field curvature chart of an optical lens according to a second embodiment of the present invention.

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

Fig. 10 is an axial 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 distortion graph of an optical lens according to a third embodiment of the present invention.

Fig. 13 is a field curve diagram of an optical lens according to a third embodiment of the present invention.

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

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

Detailed Description

In order that the objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Several embodiments of the invention are presented in the figures. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Like reference numerals refer to like elements throughout the specification.

The embodiment of the invention provides an optical lens, which sequentially comprises from an object side to an imaging surface along an optical axis: a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and an optical filter.

The first lens has negative focal power, and the object side surface of the first lens is a convex surface and the image side surface of the first lens is a concave surface; the second lens has positive focal power or negative focal power, the object side surface of the second lens is a convex surface or a concave surface, and the image side surface of the second lens is a concave surface or a convex surface; the third lens has positive focal power, the object side surface of the third lens is a convex surface or a concave surface, and the image side surface of the third lens is a convex surface; the fourth lens has positive focal power, and the object side surface of the fourth lens is a convex surface and the image side surface of the fourth lens is a convex surface; the fifth lens has negative focal power, the object side surface of the fifth lens is a convex surface or a concave surface, and the image side surface of the fifth lens is a concave surface; the sixth lens element has positive refractive power, and has a convex object-side surface and a convex image-side surface.

In some embodiments, the first lens element has negative power, and the object-side surface is convex and the image-side surface is concave, so as to collect as much light in a large field of view as possible and make the light enter the rear optical system.

In some embodiments, the second lens element has negative refractive power, and the object-side surface is convex and the image-side surface is concave, so as to diverge the light collected by the first lens element to a certain extent, and make the light transition to the rear optical system smoothly.

In some embodiments, the second lens element has positive refractive power, and the object-side surface is concave and the image-side surface is convex, so as to collect the light collected by the first lens element to a certain extent, and make the light move smoothly and transition to the rear optical system.

In some embodiments, the third lens element has positive refractive power, and the object-side surface is concave or convex, and the image-side surface is convex, so as to collect the light rays emitted from the second lens element to a certain extent, reduce the aperture, and make the light rays smoothly transition to the rear optical system.

In some embodiments, the fourth lens element has positive refractive power, and the object-side surface is convex and the image-side surface is convex, so as to collect and adjust the light emitted from the third lens element.

In some embodiments, the fifth lens element has negative refractive power, and the object-side surface thereof is convex or concave, and the image-side surface thereof is concave, so as to disperse and adjust the light rays exiting from the fourth lens element.

In some embodiments, the sixth lens element has positive refractive power, and has a convex object-side surface and a convex image-side surface for converging light and stabilizing the light traveling toward the image-side surface.

In some embodiments, the fifth lens and the sixth lens may be glued to form a cemented lens for sharing chromatic aberration correction of the optical lens, so as to improve resolution of the optical lens, and make the structure of the optical lens more compact, which is beneficial to achieving miniaturization of the optical lens.

In some embodiments, the diaphragm may be disposed between the third lens and the fourth lens, so as to converge the range of light rays emitted from the front end of the optical lens, reduce the caliber of the rear end of the optical lens, and facilitate balancing the structures of the front lens group and the rear lens group of the diaphragm and the distribution of optical power.

In some embodiments, the maximum field angle FOV of the optical lens and the effective half-caliber DM1 of the first lens satisfy: 24.0 < FOV/DM1 < 27.0. The relation between the maximum field angle of the optical lens and the half caliber of the first lens can be reasonably set by meeting the above conditional expression, which is beneficial to the optical lens having a smaller head size and a larger field angle, thereby having a wider monitoring range and meeting the daily requirement of higher orders.

In some embodiments, the radius of curvature R51 of the fifth lens object-side surface and the radius of curvature R52 of the fifth lens image-side surface satisfy:the method comprises the steps of carrying out a first treatment on the surface of the The radius of curvature R61 of the object-side surface of the sixth lens and the radius of curvature R62 of the image-side surface of the sixth lens satisfy: />. The surface shapes of the fifth lens and the sixth lens can be reasonably controlled by meeting the above conditional expression, which is favorable for correcting the aberration of the optical lens and improving the imaging quality of the optical lens.

In some embodiments, the effective focal length f2 of the second lens and the radius of curvature R21 of the object-side surface of the second lens satisfy:the method comprises the steps of carrying out a first treatment on the surface of the The height-losing SAG21 of the second lens object-side effective diameter edge and the height-losing SAG22 of the second lens image-side effective diameter edge satisfy the following conditions: />. The optical lens meets the above conditional expression, can reasonably match the focal length and the surface shape of the second lens, is favorable for slowing down the deflection trend of light rays, better corrects the field curvature and distortion of the optical lens, and improves the imaging quality of the optical lens.

In some embodiments, the radius of curvature R31 of the third lens object-side surface and the effective focal length f of the optical lens satisfy:the method comprises the steps of carrying out a first treatment on the surface of the The effective focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.5 < f3/f < 16.0. The focal length and the surface shape of the third lens can be reasonably controlled by meeting the above conditional expression, which is favorable for modifying the field curvature and the distortion of the optical lens and ensures that the field curvature and the distortion of the optical lens are controlled at smaller levels.

In some embodiments, the radius of curvature R11 of the first lens object-side surface and the radius of curvature R12 of the first lens image-side surface satisfy: R11/R12 is more than 2.5 and less than 5.5; the height loss SAG12 of the image side effective diameter edge of the first lens and the center thickness CT1 of the first lens satisfy: SAG12/CT1 < 1.0 < 2.0. The surface type of the first lens can be reasonably controlled by meeting the above conditional expression, so that the deflection trend of light rays is slowed down, the field curvature and distortion of the optical lens are better corrected, and the risk of stray light during imaging of the optical lens is avoided.

In some embodiments, the image height IH corresponding to the maximum field angle of the optical lens and the f-number FNO of the optical lens satisfy: IH/FNO is less than 4.0mm and less than 4.7mm. The above conditional expression is satisfied, so that the optical lens can be ensured to have a larger aperture while the optical lens has a large image plane, and the balance between the large image plane and the large aperture is realized.

In some embodiments, the optical total length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.5 < TTL/f < 6.5. The volume and the length of the optical lens can be reasonably controlled to maintain the miniaturization of the optical lens by meeting the above conditional expression.

In some embodiments, the maximum field angle FOV of the optical lens satisfies: FOV is less than 100 DEG and less than 140 DEG; the maximum field angle FOV of the optical lens, the effective focal length f of the optical lens, and the image height IH corresponding to the maximum field angle of the optical lens satisfy: 55 DEG < FOV x f/IH < 70 deg. The optical lens has a large field angle and a large image plane while the optical lens has good optical performance, so that the optical lens has a wider monitoring range and meets higher-order daily requirements.

In some embodiments, the image height IH of the optical back focal length BFL of the optical lens corresponding to the maximum field angle of the optical lens satisfies: BFL/IH is more than 0.75 and less than 1.0. The optical lens can be matched with a chip with a larger size by meeting the above conditional expression, and the requirements of a large field angle and high pixels can be met.

In some embodiments, the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, and the effective focal length f3 of the third lens satisfy:. The front lens group formed by the first lens, the second lens and the third lens can enable light rays with a large angle to penetrate and enter the rear lens group formed by the fourth lens, the fifth lens and the sixth lens and the imaging surface, so that the wide angle of the optical lens is realized, and meanwhile, the marginal view field with a large angle is not easy to generate serious astigmatism, and the brightness of the view field with a large angle on the imaging surface is improved.

In some embodiments, the combined focal length f123 of the first lens, the second lens, and the third lens and the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens satisfy:the method comprises the steps of carrying out a first treatment on the surface of the The center thickness CT1 of the first lens, the center thickness CT2 of the second lens, the center thickness CT3 of the third lens, the center thickness CT4 of the fourth lens, the center thickness CT5 of the fifth lens, and the center thickness CT6 of the sixth lens satisfy: 0.8 < (CT1+CT2+CT3)/(CT4+CT5+CT6) < 1.2. The above conditional expression is satisfied, so that the front lens group and the rear lens group form a symmetrical structure about the diaphragm, which is beneficial to balancing coma and astigmatism generated by the front lens group and the rear lens group, correcting distortion of the optical lens and improving imaging quality of the optical lens.

In some embodiments, the effective focal length f of the optical lens, the effective focal length f3 of the third lens, and the effective focal length f4 of the fourth lens satisfy:the method comprises the steps of carrying out a first treatment on the surface of the The center thickness CT3 of the third lens and the center thickness CT4 of the fourth lens satisfy: CT3/CT4 is more than 1.3 and less than 1.8. The method meets the above conditional expression, can reasonably adjust the shapes of the third lens and the fourth lens, reduces the process molding difficulty, can well correct the on-axis spherical aberration of the optical lens, and improves the resolution of the optical lens.

In some embodiments, the center thickness CT1 of the first lens, the center thickness CT2 of the second lens, the center thickness CT3 of the third lens, and the effective focal length f of the optical lens satisfy: 1.3 < (CT1+CT2+CT3)/f < 1.8; the center thickness CT1 of the first lens, the center thickness CT2 of the second lens, the center thickness CT3 of the third lens, the air space AT12 on the optical axis between the first lens and the second lens, the air space AT23 on the optical axis between the second lens and the third lens, and the air space AT34 on the optical axis between the third lens and the fourth lens satisfy: 0.8 < (Ct1+Ct2+Ct3)/(AT12+AT23+AT34) < 1.4. The optical lens has compact structure by reasonably controlling the center thicknesses of the first lens, the second lens and the third lens and the spacing between the lenses, and can well improve the vertical axis chromatic aberration of the optical lens and the imaging quality of the optical lens.

In some embodiments, the fourth lens, the fifth lensThe combined focal length f456 of the lens and the sixth lens and the effective focal length f of the optical lens satisfy the following conditions:. The optical lens system meets the above conditional expression, can reasonably match the focal lengths of the fourth lens, the fifth lens and the sixth lens, is favorable for well controlling the advanced spherical aberration of the optical lens, and can reduce the turning trend of incident light, so that light is incident to an imaging surface to have a smaller incident angle, and the chip receiving efficiency is enhanced.

In some embodiments, the effective focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: f4/f is more than 1.5 and less than 4.5; the radius of curvature R41 of the fourth lens object-side surface and the radius of curvature R42 of the fourth lens image-side surface satisfy: -1.5 < R41/R42 < 0. The focal length and the surface shape of the fourth lens can be reasonably controlled by meeting the above conditional expression, which is favorable for slowing down the turning trend of light, reducing the aberration of the marginal view field and improving the imaging quality of the optical lens.

In some embodiments, the second, third, fifth, and sixth lenses are aspheric lenses, and the first and fourth lenses are spherical lenses; in some embodiments, the second, fourth, fifth, and sixth lenses are aspheric lenses and the first and third lenses are spherical lenses. By adopting the aspheric lens, aberration can be effectively corrected, imaging quality is improved, and an optical performance product with higher cost performance is provided; the spherical lens is adopted, so that the reliability of the lens can be improved, the lens can be normally used in a high-low temperature environment, and the indoor and outdoor use scenes can be considered.

According to the embodiment of the invention, the glass-plastic mixed collocation structure is adopted, and the focal power of each lens is reasonably distributed and the aspheric surface shape is optimized, so that the optical lens has the advantages of at least good imaging quality, large field angle, large image surface, small size and large aperture.

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 and are included in 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 along the optical axis direction, c is the paraxial curvature of the surface, k is the conic coefficient conic, A _2i The aspherical surface profile coefficient of the 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 S14 along an optical axis: a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a filter G1.

The first lens element L1 has a negative refractive power, wherein an object-side surface S1 of the first lens element is convex, and an image-side surface S2 of the first lens element is concave; the second lens L2 has negative focal power, the object side surface S3 of the second lens is a convex surface, and the image side surface S4 of the second lens is a concave surface; the third lens element L3 with positive refractive power has a concave object-side surface S5 and a convex image-side surface S6; the fourth lens element L4 has positive refractive power, wherein an object-side surface S7 of the fourth lens element is convex, and an image-side surface S8 of the fourth lens element is convex; the fifth lens element L5 has negative refractive power, wherein an object-side surface S9 of the fifth lens element is convex, and an image-side surface of the fifth lens element is concave; the sixth lens L6 has positive focal power, the object side surface of the sixth lens is a convex surface, the image side surface S11 of the sixth lens is a convex surface, the fifth lens L5 and the sixth lens L6 form a bonding lens, and the bonding surface is S10; the object side surface of the filter G1 is S12, and the image side surface is S13. Meanwhile, the second lens L2, the third lens L3, the fifth lens L5 and the sixth lens L6 are all aspheric lenses, and the first lens L1 and the fourth lens L4 are spherical lenses.

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

TABLE 1

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

TABLE 2

In the present embodiment, graphs of distortion, curvature of field, chromatic aberration of homeotropic axis, and chromatic aberration of axial direction of the optical lens 100 are shown in fig. 2, 3, 4, and 5, respectively.

In fig. 2, the curves represent distortions corresponding to different image heights on the image plane, the abscissa represents the distortion magnitude (unit:%) and the ordinate represents the half field angle (unit: °). As can be seen from fig. 2, the distortion of the optical lens is controlled within-45% in the imaging field required by the optical lens, which means that the distortion of the optical lens is well corrected.

In fig. 3, the curves represent field curves of different image heights in the meridian direction and the sagittal direction on the image plane, the abscissa represents the offset (unit: mm), and the ordinate represents the half field angle (unit: °). As can be seen from fig. 3, the curvature of field offset in both the meridian direction and the sagittal direction at the image plane is controlled within ±0.05mm, which indicates that the curvature of field correction of the optical lens is good.

In fig. 4, the graph shows the color difference of different image heights of the wavelengths with respect to the dominant wavelength on the image plane, the abscissa shows the color difference value (unit: μm), and the ordinate shows the normalized angle of view. As can be seen from fig. 4, in different fields of view, the chromatic aberration of the optical lens on the vertical axis with respect to the center wavelength is controlled within ±3.2 μm, which means that the chromatic aberration of the optical lens on the vertical axis is well corrected.

In FIG. 5, the graph shows axial chromatic aberration, the abscissa shows the amount of offset (unit: mm), and the ordinate shows the normalized pupil radius. As can be seen from fig. 5, the chromatic aberration offset of the dominant wavelength at the zero pupil position is controlled within ±0.01mm, and the axial chromatic aberration of the shortest wavelength and the maximum wavelength is controlled within ±0.015mm, which indicates that the axial chromatic aberration correction of the optical lens is good.

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, where the optical lens 200 includes, in order from an object side to an imaging surface S15 along an optical axis: a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a filter G1.

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

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

TABLE 3 Table 3

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

TABLE 4 Table 4

In the present embodiment, graphs of distortion, curvature of field, chromatic aberration of homeotropic axis, and chromatic aberration of axial direction of the optical lens 200 are shown in fig. 7, 8, 9, and 10, respectively.

In fig. 7, the curves represent distortions corresponding to different image heights on the image plane, the abscissa represents the distortion magnitude (unit:%) and the ordinate represents the half field angle (unit: °). As can be seen from fig. 7, the distortion of the optical lens is controlled within-45% in the imaging field required by the optical lens, which means that the distortion of the optical lens is well corrected.

In fig. 8, the curves represent field curves of different image heights in the meridian direction and the sagittal direction on the image plane, the abscissa represents the offset (unit: mm), and the ordinate represents the half field angle (unit: °). As can be seen from fig. 8, the curvature of field offset in both the meridian direction and the sagittal direction at the image plane is controlled within ±0.03mm, indicating that the curvature of field correction of the optical lens is good.

In fig. 9, the graph shows the color difference of different image heights of the wavelengths with respect to the dominant wavelength on the image plane, the abscissa shows the color difference value (unit: μm), and the ordinate shows the normalized angle of view. As can be seen from fig. 9, the vertical chromatic aberration of each wavelength with respect to the center wavelength is controlled within ±3.3 μm in different fields of view, indicating that the vertical chromatic aberration of the optical lens is also well corrected.

In FIG. 10, the graph shows axial chromatic aberration, the abscissa shows the amount of shift (unit: mm), and the ordinate shows the normalized pupil radius. As can be seen from fig. 10, the chromatic aberration offset of the dominant wavelength at the zero pupil position is controlled within ±0.01mm, and the axial chromatic aberration of the shortest wavelength and the maximum wavelength is controlled within ±0.02mm, which indicates that the axial chromatic aberration correction of the optical lens is good.

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, where the optical lens 300 includes, in order from an object side to an imaging surface S14 along an optical axis: a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a filter G1.

The first lens element L1 has a negative refractive power, wherein an object-side surface S1 of the first lens element is convex, and an image-side surface S2 of the first lens element is concave; the second lens element L2 has positive refractive power, wherein an object-side surface S3 of the second lens element is concave, and an image-side surface S4 of the second lens element is convex; the third lens element L3 with positive refractive power has a concave object-side surface S5 and a convex image-side surface S6; the fourth lens element L4 has positive refractive power, wherein an object-side surface S7 of the fourth lens element is convex, and an image-side surface S8 of the fourth lens element is convex; the fifth lens element L5 with negative focal power has a concave object-side surface S9 and a concave image-side surface; the sixth lens L6 has positive focal power, the object side surface of the sixth lens is a convex surface, the image side surface S11 of the sixth lens is a convex surface, the fifth lens L5 and the sixth lens L6 form a bonding lens, and the bonding surface is S10; the object side surface of the optical filter G1 is S12, and the image side surface is S13; meanwhile, the second lens L2, the third lens L3, the fifth lens L5 and the sixth lens L6 are all aspheric lenses, and the first lens L1 and the fourth lens L4 are spherical lenses.

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

TABLE 5

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

TABLE 6

In the present embodiment, graphs of distortion, curvature of field, chromatic aberration of homeotropic axis, and chromatic aberration of axial direction of the optical lens 300 are shown in fig. 12, 13, 14, and 15, respectively.

In fig. 12, the curves represent distortions corresponding to different image heights on the image plane, the abscissa represents the magnitude of the distortion (unit:%) and the ordinate represents the half field angle (unit: °). As can be seen from fig. 12, the distortion of the optical lens is controlled within-40% in the imaging field required by the optical lens, which means that the distortion of the optical lens is well corrected.

In fig. 13, the curves represent field curves of different image heights in the meridian direction and the sagittal direction on the image plane, the abscissa represents the offset (unit: mm), and the ordinate represents the half field angle (unit: °). As can be seen from fig. 13, the curvature of field offset in both the meridian direction and the sagittal direction at the image plane was controlled within ±0.03mm, indicating that the curvature of field correction of the optical lens was good.

In fig. 14, the graph shows the color difference of different image heights of the wavelengths with respect to the dominant wavelength on the image plane, the abscissa shows the color difference value (unit: μm), and the ordinate shows the normalized angle of view. As can be seen from fig. 14, the vertical chromatic aberration of each wavelength with respect to the center wavelength is controlled within ±3.5 μm in different fields of view, indicating that the vertical chromatic aberration of the optical lens is also well corrected.

In FIG. 15, the graph shows axial chromatic aberration, the abscissa shows the amount of shift (unit: mm), and the ordinate shows the normalized pupil radius. As can be seen from fig. 15, the chromatic aberration offset of the dominant wavelength at the zero pupil position is controlled within ±0.01mm, and the axial chromatic aberration of the shortest wavelength and the maximum wavelength is controlled within ±0.02mm, which indicates that the axial chromatic aberration correction of the optical lens is good.

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 f-number FNO, and a correlation value corresponding to each of the foregoing conditional expressions.

TABLE 7

In summary, the optical lens provided by the embodiment of the invention adopts six lenses with specific focal power and a glass-plastic mixed design, and the optical lens has the advantages of at least good imaging quality, large field angle, large image plane, small size and large aperture through specific surface shape collocation and reasonable focal power distribution, so that the requirements of manufacturer products on advanced level are better met.

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

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

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

a second lens having optical power;

a third lens having positive optical power, an image side surface of the third lens being a convex surface;

a diaphragm;

a fourth lens element with positive refractive power, wherein the object-side surface of the fourth lens element is convex, and the image-side surface of the fourth lens element is convex;

a fifth lens having negative optical power;

a sixth lens having positive optical power, an image side surface of the sixth lens being a convex surface;

wherein, the image height IH corresponding to the maximum field angle of the optical lens and the f-number FNO of the optical lens satisfy: IH/FNO is less than 4.0mm and less than 4.7mm.

2. The optical lens of claim 1, wherein an optical total length TTL of the optical lens and an effective focal length f of the optical lens satisfy: 5.5 < TTL/f < 6.5.

3. The optical lens of claim 1, wherein a maximum field angle FOV of the optical lens, an effective focal length f of the optical lens, and an image height IH corresponding to the maximum field angle of the optical lens satisfy: 55 DEG < FOV x f/IH < 70 deg.

4. The optical lens according to claim 1, wherein an image height IH of an optical back focal BFL of the optical lens corresponding to the optical lens maximum field angle satisfies: BFL/IH is more than 0.75 and less than 1.0.

5. The optical lens of claim 1, wherein an effective focal length f1 of the first lens, an effective focal length f2 of the second lens, and an effective focal length f3 of the third lens satisfy:。

6. the optical lens of claim 1, wherein a combined focal length f123 of the first lens, the second lens and the third lens and a combined focal length f456 of the fourth lens, the fifth lens and the sixth lens satisfy:。

7. the optical lens of claim 1, wherein an effective focal length f of the optical lens, an effective focal length f3 of the third lens, and an effective focal length f4 of the fourth lens satisfy:。

8. the optical lens of claim 1, wherein a center thickness CT1 of the first lens, a center thickness CT2 of the second lens, a center thickness CT3 of the third lens, and an effective focal length f of the optical lens satisfy: 1.3 < (CT1+CT2+CT3)/f < 1.8.

9. The optical lens of claim 1, wherein a combined focal length f456 of the fourth lens, the fifth lens and the sixth lens and an effective focal length f of the optical lens satisfy:。

10. 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: 1.5 < f4/f < 4.5.