A wide-angle photographic lens

Abstract

The embodiment of the present application discloses a wide-angle camera lens. The wide-angle camera lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence along an optical axis from an object plane to an image plane; the first lens has positive refractive power, the second lens has positive refractive power, the third lens has negative refractive power, the fourth lens has negative refractive power, the fifth lens has positive refractive power, and the sixth lens has positive refractive power. The embodiment of the present application is configured or approximately configured as a traditional double-Gaussian symmetric optical system, so that the light ray trend and the refraction angle of the object side and the image side space are symmetrical, and the refractive power of the front and rear symmetrical lenses is matched, and the reasonable air gap adjustment of different lens pieces and the optimization of the lens aperture are matched, which helps to effectively correct the aberration, realize small distortion, small chromatic aberration and low field curvature, and helps to compress the front and rear lengths of the whole lens and reduce the volume of the whole lens.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and more particularly to a wide-angle photographic lens. Background Technology

[0002] With the rapid development of photographic technology, camera lenses play an important role in landscape photography, portrait photography, and graphic arts. Due to the influence of their applicable scenarios and artistic nature, these lenses are required to have a wide field of view, low distortion, low field curvature, low chromatic aberration, small size, and low cost.

[0003] Currently available lenses often struggle to achieve a balance among these specifications. For example, higher resolution lenses tend to have greater distortion, causing distortion in portraits or landscapes; or, while meeting aberration design requirements, the lenses are often bulky and expensive; or, while achieving aberration requirements, higher field curvature makes edge and center focusing more difficult. Therefore, developing a high-resolution photographic lens that meets all design specifications is essential. Summary of the Invention

[0004] This invention provides a wide-angle photographic lens, aiming to achieve a lens solution with a half-frame target surface, wide angle, low distortion, small size and low manufacturing cost, achieving technical specifications of -0.5% ≤ optical distortion ≤ 2.5%; 50° ≤ diagonal field of view ≤ 60°.

[0005] This invention provides a wide-angle photographic lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object plane to the image plane;

[0006] The first lens has positive optical power, the second lens has positive optical power, the third lens has negative optical power, the fourth lens has negative optical power, the fifth lens has positive optical power, and the sixth lens has positive optical power.

[0007] Optionally, the first lens to the sixth lens satisfy the following condition:

[0008] 0.668 < Φ1 / Φ < 0.935;

[0009] 1.009 < Φ2 / Φ < 1.410;

[0010] -1.875 < Φ3 / Φ < -1.492;

[0011] -1.664 < Φ4 / Φ < -1.434;

[0012] 1.172 < Φ5 / Φ < 1.703;

[0013] 0.413 < Φ6 / Φ < 0.958;

[0014] Wherein, Φ1 is the optical power of the first lens, Φ2 is the optical power of the second lens, Φ3 is the optical power of the third lens, Φ4 is the optical power of the fourth lens, Φ5 is the optical power of the fifth lens, Φ6 is the optical power of the sixth lens, and Φ is the optical power of the wide-angle lens.

[0015] Optionally, the first lens satisfies the following condition: -1.2456≤(C1-C2) / (C1+C2)≤-0.2976;

[0016] Wherein, C1 is the curvature of the object side of the first lens, and C2 is the curvature of the image side of the first lens.

[0017] Optionally, the first lens to the sixth lens satisfy the following condition:

[0018] 0.5649 < Φ1_3 / Φ < 0.6487;

[0019] 0.7450 < Φ4_6 / Φ < 1.0982;

[0020] Wherein, Φ1_3 is the optical power of the lens group consisting of the first lens, the second lens and the third lens; Φ4_6 is the optical power of the lens group consisting of the fourth lens, the fifth lens and the sixth lens.

[0021] Optionally, the object-side surface of the first lens is convex, and the image-side surface is concave.

[0022] The object-side surface of the second lens is convex, and the image-side surface is concave.

[0023] The object-side surface of the third lens is convex, and the image-side surface is concave.

[0024] The object-side surface of the sixth lens is concave, and the image-side surface is also concave.

[0025] Optionally, the first lens is an aspherical glass lens, and the second to sixth lenses are all spherical glass lenses.

[0026] Optionally, the first lens satisfies the following condition:

[0027] -1.204 <K1<-0.174;

[0028] -3.982 <K2<-0.354;

[0029] Wherein, K1 is the conic coefficient of the object side of the first lens, and K2 is the conic coefficient of the image side of the first lens.

[0030] Optionally, the fourth lens and the fifth lens satisfy the following conditions:

[0031] -1.1840≤1000*(Φ4 / VD4+Φ5 / VD5)≤0.421;

[0032] Wherein, Φ4 is the optical power of the fourth lens, Φ5 is the optical power of the fifth lens; VD4 is the Abbe number of the fourth lens, and VD5 is the Abbe number of the fifth lens.

[0033] Optionally, the fourth lens and the fifth lens satisfy the following conditions:

[0034] 26.4781 <VD4<40.8475;

[0035] 33.3090 <VD5<40.8475。

[0036] Optionally, the wide-angle lens satisfies the following condition: 1.1785 <TTL / f<1.2890;

[0037] Where TTL is the total optical length of the wide-angle lens, and f is the focal length of the wide-angle lens.

[0038] The technical solution of this invention involves setting a wide-angle photographic lens comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object plane to the image plane. The first lens has a positive optical power, the second lens has a positive optical power, the third lens has a negative optical power, the fourth lens has a negative optical power, the fifth lens has a positive optical power, and the sixth lens has a positive optical power. The purpose is to set the optical powers of the first three lenses and the last three lenses of the lens to a symmetrical or approximately symmetrical relationship, thereby constructing or approximately constructing a traditional double Gaussian symmetrical optical system. This allows the light path and refraction angle in the object-side and image-side spaces to be symmetrical. By coordinating the optical powers of the symmetrical lenses, and by adjusting the air gaps of different lens components and optimizing the lens aperture, it helps to effectively correct aberrations, achieving small distortion, small chromatic aberration, and low field curvature. On the other hand, it helps to compress the overall length of the lens and reduce its overall size. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of a wide-angle photographic lens provided in Embodiment 1 of the present invention;

[0040] Figure 2 yes Figure 1 The MTF curve of the resolution of the wide-angle lens is shown.

[0041] Figure 3 yes Figure 1The spherical aberration curve of the wide-angle camera lens is shown.

[0042] Figure 4 yes Figure 1 The chromatic aberration diagram of the wide-angle camera lens shown;

[0043] Figure 5 yes Figure 1 The field curvature distortion diagram of the wide-angle camera lens is shown.

[0044] Figure 6 This is a schematic diagram of the structure of a wide-angle photographic lens provided in Embodiment 2 of the present invention;

[0045] Figure 7 yes Figure 5 The MTF curve of the resolution of the wide-angle lens is shown.

[0046] Figure 8 yes Figure 5 The spherical aberration curve of the wide-angle camera lens is shown.

[0047] Figure 9 yes Figure 5 The chromatic aberration diagram of the wide-angle camera lens shown;

[0048] Figure 10 yes Figure 5 The field curvature distortion diagram of the wide-angle camera lens is shown.

[0049] Figure 11 This is a schematic diagram of the structure of a wide-angle photographic lens provided in Embodiment 3 of the present invention;

[0050] Figure 12 yes Figure 11 The MTF curve of the resolution of the wide-angle lens is shown.

[0051] Figure 13 yes Figure 11 The spherical aberration curve of the wide-angle camera lens is shown.

[0052] Figure 14 yes Figure 11 The chromatic aberration diagram of the wide-angle camera lens shown;

[0053] Figure 15 yes Figure 11 The image shows the field curvature distortion of a wide-angle camera lens. Detailed Implementation

[0054] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0055] The terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "on" or "below" another element, it can be formed not only directly on or below the other element, but also indirectly on or below it through intermediate elements. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] The term "comprising" and its variations as used in this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0057] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish the corresponding contents and are not used to limit the order or interdependence.

[0058] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0059] Figure 1 This is a schematic diagram of the structure of a wide-angle photographic lens provided in Embodiment 1 of the present invention, for reference. Figure 1 The wide-angle camera lens includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens 60 arranged sequentially along the optical axis from the object plane to the image plane. The first lens 10 has positive optical power, the second lens 20 has positive optical power, the third lens 30 has negative optical power, the fourth lens 40 has negative optical power, the fifth lens 50 has positive optical power, and the sixth lens 60 has positive optical power.

[0060] First, for optical lenses, optical power equals the difference between the image-side beam convergence and the object-side beam convergence; it characterizes the optical system's ability to deflect light. The larger the absolute value of optical power, the stronger the bending ability of light; the smaller the absolute value, the weaker the bending ability. When optical power is positive, the refraction of light is converging; when optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group).

[0061] In the photographic lens provided in this embodiment, each lens can be fixed to a lens barrel. Figure 1 (not shown in the image) such as Figure 1 As shown, the lens also includes an aperture stop 70, which can be positioned between the third lens 30 and the fourth lens 40. In this embodiment, the aperture stop 70 is specifically positioned on the object side of the fourth lens 40. This embodiment sets the optical power of the six lenses sequentially as positive, positive, negative, negative, positive, positive, and places the aperture stop 70 between the third and fourth lenses. The purpose is to establish a symmetrical or approximately symmetrical optical power relationship between the front three lenses and the rear three lenses, thereby constructing or approximately constructing a traditional double-Gaussian symmetrical optical system. Those skilled in the art will understand that, due to the symmetrical relationship, a traditional double-Gaussian symmetrical optical system allows for symmetrical light paths and refraction angles on the object and image sides. This enables effective aberration correction, achieving small distortion, small chromatic aberration, and low field curvature, and also helps to compress the overall length and size of the lens.

[0062] In one specific embodiment, optionally, the first lens 10 to the sixth lens 60 satisfy the following conditions: 0.668 < Φ1 / Φ < 0.935; 1.009 < Φ2 / Φ < 1.410; -1.875 < Φ3 / Φ < -1.492; -1.664 < Φ4 / Φ < -1.434; 1.172 < Φ5 / Φ < 1.703; 0.413 < Φ6 / Φ < 0.958; wherein Φ1 is the optical power of the first lens 10, Φ2 is the optical power of the second lens 20, Φ3 is the optical power of the third lens 30, Φ4 is the optical power of the fourth lens 40, Φ5 is the optical power of the fifth lens 50, Φ6 is the optical power of the sixth lens 60, and Φ is the optical power of the wide-angle lens.

[0063] In this embodiment, by limiting the optical power ratio of each lens to the overall lens and adjusting the optical power range of each lens, the entire lens can be made closer to a traditional double Gaussian symmetrical optical system, thereby optimizing the aberration correction effect and enabling the wide-angle camera lens to achieve the characteristics of small distortion, small chromatic aberration and low field curvature.

[0064] Further optionally, the first lens 10 satisfies the following condition: -1.2456≤(C1-C2) / (C1+C2)≤-0.2976; where C1 is the curvature of the object side of the first lens 10 and C2 is the curvature of the image side of the first lens 10.

[0065] In this embodiment, by limiting the curvature of the object side and image side of the first lens 10 to satisfy the above relationship, it is essentially to further limit the surface shape of the first lens 10 under the condition that the first lens of the lens satisfies the positive optical power, so that it can receive more incident light, increase the field of view, and realize the wide-angle characteristics of the lens.

[0066] Further optionally, the first lens 10 to the sixth lens 60 satisfy the following conditions: 0.5649 < Φ1_3 / Φ < 0.6487; 0.7450 < Φ4_6 / Φ < 1.0982; where Φ1_3 is the optical power of the lens group composed of the first lens 10, the second lens 20 and the third lens 30; and Φ4_6 is the optical power of the lens group composed of the fourth lens 40, the fifth lens 50 and the sixth lens 60.

[0067] In this embodiment, the optical power ratio of the lens group before and after the aperture stop 70 is limited to that of the lens group as a whole, and the optical power range of the lens group is adjusted. This further ensures that the entire lens is closer to the traditional double Gaussian symmetrical optical system, so that the optical distortion of the lens and other field aberrations can be effectively suppressed. This helps to reduce the angle of incidence of light, reduce lens sensitivity, reduce distortion and field area, optimize the aberration correction effect, and enable the wide-angle camera lens to achieve characteristics such as small distortion, small chromatic aberration and low field curvature.

[0068] In one specific embodiment, optionally, the object-side surface of the first lens 10 is convex and the image-side surface is concave; the object-side surface of the second lens 20 is convex and the image-side surface is concave; the object-side surface of the third lens 30 is convex and the image-side surface is concave; and the object-side surface of the sixth lens 60 is concave and the image-side surface is concave. More specifically, in embodiments of the present invention, optionally, the opposing surfaces of the fourth lens 40 and the fifth lens 50 can be cemented together to form a cemented lens group.

[0069] In this embodiment, by designing the surface profiles of the above-mentioned lenses, in essence, the three lenses before and after the aperture 70, especially the first lens 10 and the sixth lens 60, are set to be symmetric or approximately symmetric shapes. Thereby, the light ray trends and refraction angles in the object side and image side spaces can be controlled to have symmetric or approximately symmetric effects, ensuring that this lens can achieve a traditional double-Gauss symmetric optical system. Specifically, by restricting the first lens 10, the second lens 20, and the third lens 30 to satisfy the above-mentioned surface profiles, when the bending direction of the lens is beneficial for the lens with a smaller aperture, it is conducive to collecting light rays with a larger field angle, reflecting the function of compressing the lens volume. At the same time, it reduces the light propagation height inside the lens, reduces aberration, and realizes the characteristics of small volume, wide angle, and small aberration. The sixth lens 60 is the last lens of the lens, and this lens is a positive lens, mainly used for converging light rays, controlling the back focal distance, and playing a role in compressing the total length of the lens. Meeting the above requirements is also beneficial for the flat filter to have sufficient installation space. In addition, the fourth lens 40 and the fifth lens 50 are combined into a cemented lens group, which can not only reduce the distance between the lenses, facilitate the reduction of the overall volume of the lens, but also appropriately correct chromatic aberration, improve field curvature and coma, thereby further optimizing and correcting the imaging quality.

[0070] Further, in the embodiment of the present invention, the first lens 10 is an aspherical glass lens, and the second lens 20 to the sixth lens 60 are all spherical glass lenses.

[0071] Among them, by restricting all six lenses to be glass lenses, the characteristics of the glass material can be utilized to reduce the sensitivity of imaging to temperature, reduce the deformation degree of the lens at different temperatures, and ensure clear imaging in high and low temperature environments. And by designing the remaining five lenses except the first lens 10 to be spherical glass lenses, on the basis that the lens only has six lenses in total and has a low material cost, the processing difficulty of the glass lens can be reduced, and the processing cost can be reduced, which is beneficial for reducing the manufacturing cost and realizing mass production.

[0072] Still further, the first lens 10 satisfies the following conditions: -1.204 < K1 < -0.174; -3.982 < K2 < -0.354; where K1 is the conic coefficient of the object side surface of the first lens 10, and K2 is the conic coefficient of the image side surface of the first lens 10.

[0073] As described above, in the embodiments of the present invention, the first lens 10 can be designed as an aspherical lens. On this basis, K1 and K2 are the conic coefficients of the aspherical object-side surface and the image-side surface respectively. The conic coefficient affects the resolution of the optical system. The adjustment of this coefficient is the key to optimizing the imaging quality. By restricting the object side and the image side of the first lens 10 to satisfy the above relationship ranges respectively, the layout of the optical system can be optimized. Inserting an aspherical lens at the position of the first lens can utilize the characteristic that different apertures of the aspherical surface have different curvature values, and when the light rays in different fields of view are relatively separated, the effects of correcting field aberrations such as distortion and field curvature can be achieved.

[0074] In a specific embodiment, optionally, the fourth lens 40 and the fifth lens 50 satisfy the following conditions: -1.1840 ≤ 1000 * (Φ4 / VD4 + Φ5 / VD5) ≤ 0.421; where, Φ4 is the optical power of the fourth lens 40, Φ5 is the optical power of the fifth lens 50; VD4 is the Abbe number of the fourth lens 40, and VD5 is the Abbe number of the fifth lens 50. More specifically, the fourth lens 40 and the fifth lens 50 can be set to satisfy the following conditions: 26.4781 < VD4 < 40.8475; 33.3090 < VD5 < 40.8475.

[0075] Among them, the Abbe constant represents the index of the dispersion ability of the medium. The larger the Abbe constant, the lighter the dispersion. In this embodiment, according to the achromatic aberration formula of the positive and negative optical power doublet lens, restricting the fourth lens 40 and the fifth lens 50 to satisfy the above optical power and Abbe number ranges is beneficial to the correction of axial chromatic aberration and lateral chromatic aberration, and higher resolution and better imaging performance can be obtained.

[0076] In a specific embodiment, optionally, the wide-angle photographic lens satisfies the following conditions: 1.1785 < TTL / f < 1.2890; where, TTL is the total optical length of the wide-angle photographic lens, and f is the focal length of the wide-angle photographic lens.

[0077] For the wide-angle lens in the embodiments of the present invention, the value of TTL / f is the reverse telephoto ratio. This value is usually greater than 1, indicating that the principal plane of the lens is inside the lens, and the focal plane of the lens is usually close to the image plane. When the lens satisfies the above proportional numerical requirements, the principal plane of the lens can be moved closer to the front end of the lens, which is beneficial to the compression of the total length of the lens and balances the contradiction between various aberrations of the lens and the volume and length of the lens.

[0078] Based on the same concept as above, the present invention provides three different specific embodiments. The optical power relationship and the design ranges of related physical optical parameters are shown in Table 1:

[0079] Table 1 Related physical optical parameters in each embodiment

[0080]

[0081]

[0082] In Embodiment 1 of the present invention, reference is made to Figure 1 The structure, shape, and location of each component in the system are crucial to its operation. As shown in the figure, the optical system consists of six optical lenses. The aperture stop 70 is located on the object-side surface of the fourth lens 40. Furthermore, a planar glass 70 is disposed along the object-side to the image-side surface; the planar glass 70 is located on the image-side surface of the sixth lens 60. The planar glass 70 protects the photosensitive chip in the imaging sensor, which converts the light signals collected by the telephoto lens into electrical signals, thereby ensuring the imaging effect of the telephoto lens. Specifically, in Embodiment 1, the wide-angle photographic lens achieves the following technical parameters: image plane size Φ28.4mm, field of view 52.6°, total lens length 35mm, and distortion 2.59%.

[0083] like Figure 1 The parameter design values ​​of each lens in the wide-angle camera lens of Embodiment 1 are shown in Table 2:

[0084] Table 2 shows a design value for each lens in the wide-angle camera lens in Example 1.

[0085]

[0086]

[0087] The surface numbers in Table 1 are assigned according to the surface sequence of each lens; STO represents the aperture stop of the wide-angle lens; radius of curvature represents the curvature of the lens surface, with positive values ​​indicating the surface bends towards the image plane and negative values ​​indicating the surface bends towards the object plane; thickness represents the central axial distance between the current surface and the next surface; refractive index represents the ability of the material between the current and next surfaces to deflect light, with a blank space indicating the current location is air and the refractive index is 1; Abbe number represents the dispersion characteristics of the material between the current and next surfaces. Half-aperture indicates half the aperture size of the current surface, and the same applies to the following.

[0088] The aspherical lenses in Table 2 satisfy the following formula:

[0089]

[0090] Where Z is the aspherical elevation, c is the fundamental curvature at the vertex, k is the conic coefficient, r is the radial coordinate perpendicular to the optical axis, and a i a is the coefficient of the higher-order term. i r 2i For aspherical surfaces, the term is of higher order.

[0091] The coefficient values ​​for the aspherical surfaces in the above embodiment 1 are shown in Table 3:

[0092] Table 3 Aspheric coefficients of the first lens in Example 1 Table 3 Aspheric coefficients of the first lens in Example 1

[0093] Face number <![CDATA[a2]]> <![CDATA[a3]]> <![CDATA[a4]]> <![CDATA[a5]]> <![CDATA[a6]]> <![CDATA[a7]]> <![CDATA[a8]]> 1 3.3023E-06 3.4914E-07 -1.4201E-08 2.1383E-10 -6.0495E-12 0.0000E+00 0 2 1.9424E-05 1.2528E-07 8.4070E-10 -5.8181E-10 2.0005E-12 0.0000E+00 0

[0094] Where 3.3023E-06 indicates that the coefficient a2 is 3.3023 * 10 -6 And so on.

[0095] Figure 2 yes Figure 1 The image shows the MTF (Mean Transmission Factor) curve of a wide-angle lens. MTF is one of the most commonly used methods for evaluating lens resolution in modern optical design. The horizontal axis represents spatial frequency, and the vertical axis represents contrast ratio. The ideal curve represents the diffraction limit at the highest point, indicating the physical limits of the lens at this parameter. The vertical axis of the curve corresponds to the contrast ratio of black and white line boundaries. The horizontal axis corresponds to the number of black and white lines within 1 mm. S and T correspond to the sagitta and meridional of each field of view. Figure 2 It can be seen that the system approaches the diffraction limit well at each wavelength in each field of view, indicating that the aberrations at each wavelength are well corrected. At the same time, there is no significant dispersion in the sagittal and meridional axes of each field of view, indicating that the astigmatism of the system is also well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0096] Figure 3 yes Figure 1 The graph shows the spherical aberration curve of the wide-angle camera lens. The vertical axis is dimensionless, representing the normalized entrance pupil radius, while the horizontal axis represents the distance from the image sensor surface to the focal point on each wavelength axis. All wavelength values ​​are within ±0.1 mm, indicating that the optical system has good axial chromatic aberration correction.

[0097] Figure 4 yes Figure 1 The diagram shows the chromatic aberration of a wide-angle camera lens. In the coordinate system shown, the horizontal axis represents the distance from the reference wavelength's position, in μm; the vertical axis represents the normalized image height, which has no unit; the solid lines on either side of the zero point represent the Airy disk radius. Figure 4 As can be seen, this embodiment effectively controls chromatic aberration, meaning that during imaging, the distance difference between the reference wavelength and the surrounding wavelengths is small.

[0098] Figure 5 yes Figure 1 The diagram shows the field curvature distortion of a wide-angle camera lens. In the coordinate system on the left, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents meridion and S represents arc distortion. Figure 5It can be seen that the field curvature is effectively controlled in this embodiment, meaning that the difference in image quality between the center and the periphery is small during imaging; in the coordinate system on the right, the horizontal axis represents the magnitude of distortion, expressed as a percentage; the vertical axis represents the normalized image height, which has no unit; from Figure 5 It can be seen that the distortion of the lens provided in this embodiment is 0% ≤ distortion ≤ 2.5%.

[0099] Figure 6 This is a schematic diagram of the structure of a wide-angle photographic lens provided in Embodiment 2 of the present invention. In Embodiment 2 of the present invention, reference is made to... Figure 6 It is known that this optical system also consists of six optical lenses, with the aperture stop 70 located between the third lens 30 and the fourth lens 40. Similarly, a planar glass 70 is also provided along the object plane to the image plane; the planar glass 70 is located on the image-side surface of the sixth lens 60, and the planar glass 70 can protect the photosensitive chip in the imaging sensor. Specifically, in embodiment two, the wide-angle photographic lens can achieve the following technical parameters: image plane size Φ28.4mm, field of view 53.586°, total lens length 33mm, and distortion 0.52%.

[0100] like Figure 6 The parameter design values ​​of each lens in the wide-angle camera lens of Embodiment 2 are shown in Table 4:

[0101] Table 4 shows a design value for each lens in the wide-angle camera lens in Example 2.

[0102]

[0103]

[0104] The surface numbers in Table 4 are assigned according to the surface sequence of each lens; STO represents the aperture stop of the wide-angle lens; radius of curvature represents the curvature of the lens surface, with positive values ​​indicating the surface bends towards the image plane and negative values ​​indicating the surface bends towards the object plane; thickness represents the central axial distance between the current surface and the next surface; refractive index represents the ability of the material between the current and next surfaces to deflect light, with a blank space indicating the current location is air and the refractive index is 1; Abbe number represents the dispersion characteristics of the material between the current and next surfaces. Half-aperture indicates half the aperture size of the current surface, and the same applies to the following.

[0105] The aspherical lenses in Table 4 satisfy the following formula:

[0106]

[0107] Where Z is the aspherical elevation, c is the fundamental curvature at the vertex, k is the conic coefficient, r is the radial coordinate perpendicular to the optical axis, and a i a is the coefficient of the higher-order term. i r2i For aspherical surfaces, the term is of higher order.

[0108] The coefficient values ​​for the aspherical surfaces in the above embodiment two are shown in Table 5:

[0109] Table 5 Aspheric coefficients of the first lens in Example 2

[0110] Face number <![CDATA[a2]]> <![CDATA[a3]]> <![CDATA[a4]]> <![CDATA[a5]]> <![CDATA[a6]]> <![CDATA[a7]]> <![CDATA[a8]]> 1 1.5855E-05 1.3808E-06 -8.8520E-08 1.7460E-09 -2.8242E-11 1.5855E-05 1.3808E-06 2 6.0752E-05 1.0088E-06 -1.0430E-07 1.9624E-09 -2.8996E-11 6.0752E-05 1.0088E-06

[0111] Where 1.5855E-05 indicates that the coefficient a2 is 1.5855 * 10 -5 And so on.

[0112] Figure 7 yes Figure 5 The image shows the MTF (Mean Transmission Factor) curve of a wide-angle lens. MTF is one of the most commonly used methods for evaluating lens resolution in modern optical design. The horizontal axis represents spatial frequency, and the vertical axis represents contrast ratio. The ideal curve represents the diffraction limit at the highest point, indicating the physical limits of the lens at this parameter. The vertical axis of the curve corresponds to the contrast ratio of black and white line boundaries. The horizontal axis corresponds to the number of black and white lines within 1 mm. S and T correspond to the sagitta and meridional of each field of view. Figure 7 It can be seen that the system approaches the diffraction limit well at each wavelength in each field of view, indicating that the aberrations at each wavelength are well corrected. At the same time, there is no significant dispersion in the sagittal and meridional axes of each field of view, indicating that the astigmatism of the system is also well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0113] Figure 8 yes Figure 5 The graph shows the spherical aberration curve of the wide-angle camera lens. The vertical axis is dimensionless, representing the normalized entrance pupil radius, while the horizontal axis represents the distance from the image sensor surface to the focal point on each wavelength axis. All wavelength values ​​are within ±0.1 mm, indicating that the optical system has good axial chromatic aberration correction.

[0114] Figure 9 yes Figure 5 The diagram shows the chromatic aberration of a wide-angle camera lens. In the coordinate system shown, the horizontal axis represents the distance from the reference wavelength's position, in μm; the vertical axis represents the normalized image height, which has no unit; the solid lines on either side of the zero point represent the Airy disk radius. Figure 9 As can be seen, this embodiment effectively controls chromatic aberration, meaning that during imaging, the distance difference between the reference wavelength and the surrounding wavelengths is small.

[0115] Figure 10 yes Figure 5The diagram shows the field curvature distortion of a wide-angle camera lens. In the coordinate system on the left, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents meridion and S represents arc distortion. Figure 10 It can be seen that the field curvature is effectively controlled in this embodiment, meaning that the difference in image quality between the center and the periphery is small during imaging; in the coordinate system on the right, the horizontal axis represents the magnitude of distortion, expressed as a percentage; the vertical axis represents the normalized image height, which has no unit; from Figure 10 As can be seen, the distortion of the lens provided in this embodiment is -0.5% ≤ 0%.

[0116] Figure 11 This is a schematic diagram of the structure of a wide-angle photographic lens provided in Embodiment 3 of the present invention. In Embodiment 3 of the present invention, reference is made to... Figure 11 It is known that this optical system also consists of 6 optical lenses. Similarly, the aperture stop 70 is located between the third lens 30 and the fourth lens 40, and a flat glass 70 is also provided along the object plane to the image plane. The flat glass 70 is located on the image-side surface of the sixth lens 60, and the flat glass 70 can protect the photosensitive chip in the imaging sensor. Specifically, in embodiment three, the wide-angle photographic lens can achieve the following technical parameters: image plane size Φ28.4mm, field of view 52.8°, total lens length 33mm, and distortion 2.1%.

[0117] like Figure 11 The parameter design values ​​of each lens in the wide-angle camera lens of Embodiment 3 are shown in Table 6:

[0118] Table 6 shows a design value for each lens in the wide-angle camera lens in Example 3.

[0119]

[0120]

[0121] The surface numbers in Table 6 are assigned according to the surface sequence of each lens; STO represents the aperture of the wide-angle lens; radius of curvature represents the curvature of the lens surface, with positive values ​​indicating the surface bends towards the image plane and negative values ​​indicating the surface bends towards the object plane; thickness represents the central axial distance between the current surface and the next surface; refractive index represents the ability of the material between the current and next surfaces to deflect light, with a blank space indicating the current location is air and the refractive index is 1; Abbe number represents the dispersion characteristics of the material between the current and next surfaces. Half-aperture indicates half the aperture size of the current surface, and the same applies to the following.

[0122] The aspherical lenses in Table 6 satisfy the following formula:

[0123]

[0124] Where Z is the aspherical elevation, c is the fundamental curvature at the vertex, k is the conic coefficient, r is the radial coordinate perpendicular to the optical axis, and a i a is the coefficient of the higher-order term. i r 2i For aspherical surfaces, the term is of higher order.

[0125] The coefficient values ​​of the aspherical surfaces in the above embodiment three are shown in Table 7:

[0126] Table 7 Aspheric coefficients of the first lens in Example 3

[0127] Face number <![CDATA[a2]]> <![CDATA[a3]]> <![CDATA[a4]]> <![CDATA[a5]]> <![CDATA[a b ]]> <![CDATA[a7]]> <![CDATA[a8]]> 1 -1.7909E-05 -4.7928E-08 -2.0308E-08 2.7465E-10 -6.4774E-12 0 0 2 -1.1367E-06 -4.0122E-07 -5.3933E-09 -3.0123E-10 1.0372E-13 0 0

[0128] Where -1.7909E-05 indicates that the coefficient a2 is -1.7909 * 10 -5 And so on.

[0129] Figure 12 yes Figure 11 The image shows the MTF (Mean Transmission Factor) curve of a wide-angle lens. MTF is one of the most commonly used methods for evaluating lens resolution in modern optical design. The horizontal axis represents spatial frequency, and the vertical axis represents contrast ratio. The ideal curve represents the diffraction limit at the highest point, indicating the physical limits of the lens at this parameter. The vertical axis of the curve corresponds to the contrast ratio of black and white line boundaries. The horizontal axis corresponds to the number of black and white lines within 1 mm. S and T correspond to the sagitta and meridional of each field of view. Figure 12 It can be seen that the system approaches the diffraction limit well at each wavelength in each field of view, indicating that the aberrations at each wavelength are well corrected. At the same time, there is no significant dispersion in the sagittal and meridional axes of each field of view, indicating that the astigmatism of the system is also well corrected, thus ensuring that the optical system can achieve the high-resolution imaging requirements.

[0130] Figure 13 yes Figure 11 The graph shows the spherical aberration curve of the wide-angle camera lens. The vertical axis is dimensionless, representing the normalized entrance pupil radius, while the horizontal axis represents the distance from the image sensor surface to the focal point on each wavelength axis. All wavelength values ​​are within ±0.1 mm, indicating that the optical system has good axial chromatic aberration correction.

[0131] Figure 14 yes Figure 11 The diagram shows the chromatic aberration of a wide-angle camera lens. In the coordinate system shown, the horizontal axis represents the distance from the reference wavelength's position, in μm; the vertical axis represents the normalized image height, which has no unit; the solid lines on either side of the zero point represent the Airy disk radius. Figure 14 As can be seen, this embodiment effectively controls chromatic aberration, meaning that during imaging, the distance difference between the reference wavelength and the surrounding wavelengths is small.

[0132] Figure 15 yes Figure 11 The diagram shows the field curvature distortion of a wide-angle camera lens. In the coordinate system on the left, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents meridion and S represents arc distortion. Figure 15 It can be seen that the field curvature is effectively controlled in this embodiment, meaning that the difference in image quality between the center and the periphery is small during imaging; in the coordinate system on the right, the horizontal axis represents the magnitude of distortion, expressed as a percentage; the vertical axis represents the normalized image height, which has no unit; from Figure 15 It can be seen that the lens provided in this embodiment has a distortion of 0% ≤ 2.1%.

[0133] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A wide-angle photographic lens, characterized in that, It includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object plane to the image plane; The first lens has positive optical power, the second lens has positive optical power, the third lens has negative optical power, the fourth lens has negative optical power, the fifth lens has positive optical power, and the sixth lens has positive optical power. The first lens through the sixth lens satisfy the following conditions: 0.668 < Φ1 / Φ < 0.935; 1.009 < Φ2 / Φ < 1.410; -1.875 < Φ3 / Φ < -1.492; -1.664 < Φ4 / Φ < -1.434; 1.172 < Φ5 / Φ < 1.703; 0.413 < Φ6 / Φ < 0.958; Wherein, Φ1 is the optical power of the first lens, Φ2 is the optical power of the second lens, Φ3 is the optical power of the third lens, Φ4 is the optical power of the fourth lens, Φ5 is the optical power of the fifth lens, Φ6 is the optical power of the sixth lens, and Φ is the optical power of the wide-angle lens; wherein, the total number of lenses is 6. The object-side surface of the first lens is convex, and the image-side surface is concave. The object-side surface of the second lens is convex. The object-side surface of the third lens is convex, and the image-side surface is concave. The object-side surface of the sixth lens is concave, and the image-side surface is convex.

2. The wide-angle photographic lens according to claim 1, characterized in that, The first lens satisfies the following condition: -1.2456≤(C1-C2) / (C1+C2)≤-0.2976; Wherein, C1 is the curvature of the object side of the first lens, and C2 is the curvature of the image side of the first lens.

3. The wide-angle photographic lens according to claim 1, characterized in that, The first lens through the sixth lens satisfy the following conditions: 0.5649 < Φ1_3 / Φ < 0.6487; 0.7450 < Φ4_6 / Φ < 1.0982; Wherein, Φ1_3 is the optical power of the lens group consisting of the first lens, the second lens and the third lens; Φ4_6 is the optical power of the lens group consisting of the fourth lens, the fifth lens and the sixth lens.

4. The wide-angle photographic lens according to claim 1, characterized in that, The first lens is an aspherical glass lens, while the second to sixth lenses are all spherical glass lenses.

5. The wide-angle photographic lens according to claim 4, characterized in that, The first lens satisfies the following condition: -1.204<K1<-0.174； -3.982<K2<-0.354； Wherein, K1 is the conic coefficient of the object side of the first lens, and K2 is the conic coefficient of the image side of the first lens.

6. The wide-angle photographic lens according to claim 1, characterized in that, The fourth lens and the fifth lens satisfy the following conditions: 26.4781 <VD4<40.8475; 33.3090 <VD5<40.8475。 7. The wide-angle photographic lens according to claim 1, characterized in that, The wide-angle lens meets the following condition: 1.1785 <TTL / f<1.2890; Where TTL is the total optical length of the wide-angle lens, and f is the focal length of the wide-angle lens.

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