CN218497251U - Fixed focus lens - Google Patents
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- CN218497251U CN218497251U CN202222879175.7U CN202222879175U CN218497251U CN 218497251 U CN218497251 U CN 218497251U CN 202222879175 U CN202222879175 U CN 202222879175U CN 218497251 U CN218497251 U CN 218497251U
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Abstract
The utility model discloses a prime lens, include along the optical axis from the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens of object plane to image plane arrange in proper order, the focal power of each lens satisfies-0.674 < phi 1/phi < 0.506,0.393 < phi 3/phi < 0.503, 0.801 < phi 5/phi < 0.689,0.411 < phi 6/phi < 0.518, each side curvature of first lens satisfies-1.808 and is less than or equal to (C1-C2)/(C1 + C2) and is less than or equal to-1.132, the biggest clear aperture of first lens and the total length of prime lens satisfy D1/TTL < 0.57. The embodiment of the utility model provides a fixed focus camera lens, optics overall length is less than or equal to 13mm, and the angle of diagonal view is greater than or equal to 135, has realized having the ultrashort wide angle fixed focus camera lens of ultrashort optics overall length, big angle of view.
Description
Technical Field
The utility model relates to an optical device technical field especially relates to a tight shot.
Background
With the development of society and the improvement of living standard, the short video enjoys life in a way of getting deep into the heart.
As an important photographing device for recording life, a VLOG (video recording) camera has the following defects in its optical system:
1. the lens is large in size, and the general optical total length is more than 20mm.
2. The field angle is small, and the common field angle is less than 120 degrees.
SUMMERY OF THE UTILITY MODEL
The utility model provides a fixed focus lens to realize having the fixed focus lens of ultrashort optical overall length, big angle of vision.
The utility model provides a fixed focus lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are arranged in sequence from an object plane to an image plane along an optical axis;
the first lens has a negative optical power, the second lens has a negative optical power, and the third lens has a positive optical power; the fourth lens has a positive optical power, the fifth lens has a negative optical power, and the sixth lens has a positive optical power;
the focal power of the first lens is phi 1, the focal power of the third lens is phi 3, the focal power of the fifth lens is phi 5, the focal power of the sixth lens is phi 6, and the focal power of the prime lens is phi, wherein-0.674 < phi 1/phi < -0.506,0.393 < phi 3/phi < 0.503, -0.801 < phi 5/phi < -0.689,0.411 < phi 6/phi < 0.518;
the curvature of the object side surface of the first lens is C1, the curvature of the image side surface of the first lens is C2, wherein the value of (C1-C2)/(C1 + C2) is more than or equal to-1.808 and less than or equal to-1.132;
the maximum clear aperture of the first lens is D1, the distance from the optical axis center of the object side surface of the first lens to the image surface is TTL, and D1/TTL is less than 0.57.
Optionally, an object-side surface of the first lens element is a convex surface, and an image-side surface of the first lens element is a concave surface;
the image side surface of the second lens is a concave surface;
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;
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 image side surface of the fifth lens is a concave surface;
the object side surface of the sixth lens element is a convex surface, and the image side surface of the sixth lens element is a convex surface.
Optionally, the fixed focus lens further includes a diaphragm;
the diaphragm is located in an optical path between the third lens and the fourth lens.
Optionally, the first lens, the second lens, the third lens, and the sixth lens are glass lenses, and the fourth lens and the fifth lens are plastic lenses.
Optionally, the first lens, the second lens and the third lens are all spherical lenses.
Optionally, the refractive index of the first lens is ND1, the refractive index of the second lens is ND2, and the refractive index of the third lens is ND3, wherein 1.64 < ND1 < 1.78,1.58 < ND2 < 1.69,1.77 < ND3 < 1.85.
Optionally, the fifth lens is an aspheric lens, and the sixth lens is a spherical lens.
Optionally, the refractive index of the fifth lens is ND5, the abbe constant of the fifth lens is VD5, the refractive index of the sixth lens is ND6, and the abbe constant of the sixth lens is VD6, where ND5 is greater than 1.61 and less than 1.69, ND6 is greater than 1.54 and less than 1.65, VD5 is greater than 18.17 and less than 28.18, and VD6 is greater than 61.28 and less than 80.13.
Optionally, a distance between an optical axis center of an image-side surface of the sixth lens element and the image plane is BFL, a distance between an optical axis center of an object-side surface of the first lens element and the image plane is TTL, and BFL/TTL is greater than 0.23.
Optionally, the distance from the center of the optical axis of the object-side surface of the first lens to the image plane is TTL, and the diagonal field angle of the fixed-focus lens is FOV, where TTL is less than or equal to 13mm and FOV is greater than or equal to 135 °.
The embodiment of the utility model provides a fixed focus camera lens, through the focal power of each lens of rational distribution, the curvature radius of each face of first lens is rationally injectd, and the maximum clear aperture D1 of the first lens of rational control and the proportional relation of the total length of optics of fixed focus camera lens, in better correction each item aberration, when realizing the requirement of resolving the image, can make the total length of optics be less than or equal to 13mm, the angle of diagonal view is greater than or equal to 135, thereby realize having ultrashort total length of optics, the ultrashort wide angle fixed focus camera lens of big angle of view.
It should be understood that the statements herein are not intended to identify key or critical features of any embodiment of the present invention, nor are they intended to limit the scope of the invention. Other features of the present invention will become apparent from the following description.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a fixed focus lens according to an embodiment of the present invention;
fig. 2 is a spherical aberration curve chart of a fixed focus lens according to a first embodiment of the present invention;
fig. 3 is a field curvature distortion diagram of a prime lens according to a first embodiment of the present invention;
fig. 4 is a schematic structural diagram of a fixed-focus lens provided in the second embodiment of the present invention;
fig. 5 is a spherical aberration curve chart of the fixed focus lens provided by the second embodiment of the present invention;
fig. 6 is a field curvature distortion diagram of a fixed focus lens provided in the second embodiment of the present invention;
fig. 7 is a schematic structural diagram of a fixed-focus lens provided in the third embodiment of the present invention;
fig. 8 is a spherical aberration curve chart of the fixed-focus lens provided in the third embodiment of the present invention;
fig. 9 is a field curvature distortion diagram of a fixed focus lens according to a third embodiment of the present invention.
Detailed Description
In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Fig. 1 is a schematic structural diagram of a fixed focus lens provided by an embodiment of the present invention, as shown in fig. 1, the embodiment of the present invention provides a fixed focus lens including a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150 and a sixth lens 160, which are sequentially arranged from an object plane to an image plane along an optical axis. The first lens 110 has a negative power, the second lens 120 has a negative power, and the third lens 130 has a positive power; the fourth lens 140 has a positive power, the fifth lens 150 has a negative power, and the sixth lens 160 has a positive power. The focal power of the first lens 110 is phi 1, the focal power of the third lens 130 is phi 3, the focal power of the fifth lens 150 is phi 5, the focal power of the sixth lens 160 is phi 6, and the focal power of the fixed focus lens is phi, wherein-0.674 < phi 1/phi < -0.506,0.393 < phi 3/phi < 0.503, -0.801 < phi 5/phi < -0.689,0.411 < phi 6/phi < 0.518. The curvature of the object side surface of the first lens 110 is C1, the curvature of the image side surface of the first lens 110 is C2, wherein the value of (C1-C2)/(C1 + C2) is more than or equal to-1.808 and less than or equal to-1.132. The maximum clear aperture of the first lens element 110 is D1, and the distance from the optical axis center of the object-side surface of the first lens element 110 to the image plane is TTL, where D1/TTL is less than 0.57.
Specifically, in the fixed focus lens provided in this embodiment, the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, and the sixth lens 160 may be disposed in a lens barrel (not shown in fig. 1), but is not limited thereto.
Wherein, the focal power is equal to the difference between the convergence of the image side light beam and the convergence of the object side light beam, which characterizes the capability of the optical system to deflect the light. The larger the absolute value of the focal power is, the stronger the bending capability to the light ray is, and the smaller the absolute value of the focal power is, the weaker the bending capability to the light ray is. When the focal power is positive, the refraction of the light is convergent; when the focal power is negative, the refraction of the light is divergent. The optical power can be suitable for representing a certain refractive surface of a lens (namely, a surface of the lens), can be suitable for representing a certain lens, and can also be suitable for representing a system (namely a lens group) formed by a plurality of lenses together.
In this embodiment, by reasonably distributing the focal power of each lens, each aberration of the fixed-focus lens can be better corrected, thereby achieving the requirement of image resolution.
Furthermore, the curvature C1 of the object side surface of the first lens 110 and the curvature C2 of the image side surface of the first lens 110 are controlled to satisfy the relation of-1.808 ≦ (C1-C2)/(C1 + C2) ≦ -1.132, so that the lens can present a 'straw hat' shaped convex structure, which is helpful for achieving the technical effect of large field angle.
Further, the TTL, which is the total optical length of the fixed focus lens, is the distance from the optical axis center of the object-side surface of the first lens element 110 to the image plane, and the proportional relationship between the maximum clear aperture D1 of the first lens element 110 and the total optical length of the fixed focus lens is reasonably controlled to satisfy that D1/TTL is less than 0.57, which is beneficial to achieving the technical effect of miniaturization of the fixed focus lens.
The maximum clear aperture D1 of the first lens element 110 may be the maximum clear aperture of the first lens element 110 when the half image height of the image plane of the fixed-focus lens is 2.4mm, and at this time, the maximum clear aperture of the first lens element 110 is not greater than 7.4mm, so as to further achieve the miniaturization of the fixed-focus lens, but is not limited thereto.
To sum up, the embodiment of the utility model provides a fixed focus camera lens, through the focal power of each lens of rational distribution, the curvature radius of each face of first lens 110 is rationally injectd, and the maximum clear aperture D1 of the first lens 110 of rational control and the proportional relation of the total optical length of fixed focus camera lens, at each item aberration of better correction, when realizing the requirement of resolving images, can make the total optical length be less than or equal to 13mm, diagonal angle of vision is greater than or equal to 135 °, thereby realize the ultrashort wide angle fixed focus camera lens that has ultrashort total optical length, big angle of vision.
As a possible implementation manner, as shown in fig. 1, the object-side surface of the first lens element 110 is convex, and the image-side surface of the first lens element 110 is concave; the image-side surface of the second lens element 120 is concave; the object-side surface of the third lens element 130 is convex, and the image-side surface of the third lens element 130 is convex; the object-side surface of the fourth lens element 140 is convex, and the image-side surface of the fourth lens element 140 is convex; the image-side surface of the fifth lens element 150 is concave; the object-side surface of the sixth lens element 160 is convex, and the image-side surface of the sixth lens element 160 is convex.
By adjusting the bending direction of the surface of each lens, focal power collocation is realized, and meanwhile, the characteristics of ultra-short optical total length and large field angle are realized, and the improvement of the integral resolution of the fixed-focus lens is facilitated, so that the imaging quality is improved.
Specifically, as shown in fig. 1, the first lens element 110 has a negative focal power, and has a convex object-side surface and a concave image-side surface, which form a "straw hat" shaped convex structure, thereby facilitating the realization of a large field angle characteristic, reducing distortion, and improving imaging quality.
The second lens element 120 has a negative focal power, and has a convex object-side surface and a concave image-side surface, which is beneficial to smooth the light beam, reduce the aberration, reduce the sensitivity of the lens, and reduce the aperture of the lens.
The third lens 130 and the fourth lens 140 both have positive focal power, which is beneficial to folding light and reducing the length of the lens.
The fifth lens 150 is a biconcave negative lens, which is beneficial to correcting curvature of field and improving imaging quality.
As a possible implementation, as shown in fig. 1, the fixed focus lens further includes an optical stop 200, and the optical stop 200 is located in the optical path between the third lens 130 and the fourth lens 140.
By disposing the stop 200 between the third lens 130 and the fourth lens 140, the lens aperture can be reduced.
As a possible embodiment, the first lens 110, the second lens 120, the third lens 130, and the sixth lens 160 are glass lenses, and the fourth lens 140 and the fifth lens 150 are plastic lenses.
In this embodiment, the prime lens includes four glass lenses and two plastic lenses, and the positions of the glass lenses and the plastic lenses in the prime lens are reasonably arranged, so that various aberrations of a better correction system are facilitated, and the requirement for resolving images is met.
By arranging the first lens element 110, the second lens element 120 and the third lens element 130, namely, the first three lens elements of the prime lens are all glass lens elements, on one hand, the incident light can be smoothly turned over, and the sensitivity of the lens elements can be reduced; meanwhile, the glass lens is ensured to have a reasonable refractive index relatively, and the cost of the prime lens is further prevented from being too high.
The fifth lens 150 is a plastic lens and disposed near the stop 200, which is favorable for correcting spherical aberration and chromatic aberration. And a sixth lens 160 is further arranged and adopts a glass lens, so that the final compensation and correction can be performed on the residual aberration of the fixed-focus lens, and the imaging quality is improved.
In addition, since the cost of the plastic lens is much lower than that of the glass lens, in this embodiment, two plastic lenses are provided, which is low in cost and light in weight.
It should be noted that the material of the plastic lens can be various plastics known to those skilled in the art, and the material of the glass lens can be various types of glass known to those skilled in the art, which is neither described nor limited in this embodiment.
As a possible implementation, the first lens 110, the second lens 120, and the third lens 130 are all spherical lenses.
The first lens 110, the second lens 120 and the third lens 130 are spherical lenses, which is beneficial to reducing the manufacturing cost of glass lenses and realizing the cost control of the fixed-focus lens.
As a possible implementation mode, the refractive index of the first lens 110 is ND1, the refractive index of the second lens 120 is ND2, and the refractive index of the third lens 130 is ND3, wherein 1.64 < ND1 < 1.78,1.58 < ND2 < 1.69,1.77 < ND3 < 1.85.
The refractive index is a ratio of a propagation speed of light in vacuum to a propagation speed of light in the medium, and is mainly used for describing the refractive power of materials to light, the refractive indexes of different materials are different, and the higher the refractive index of a material is, the stronger the refractive power of incident light is.
In this embodiment, by arranging the first lens element 110, the second lens element 120 and the third lens element 130 in a matched manner, i.e. the refractive indexes of the first three lens elements of the prime lens, the incident light can be turned smoothly and excessively, the sensitivity of the lens elements can be reduced, the first three lens elements can be ensured to have reasonable refractive indexes, and the cost of the prime lens can be prevented from being excessively high.
In one possible embodiment, the fifth lens 150 is an aspheric lens, and the sixth lens 160 is a spherical lens.
Wherein, adopt aspheric lens can correct spherical aberration among the optical system, effectively promote the imaging quality of tight shot.
Specifically, the fifth lens element 150 is an aspheric lens element disposed near the stop 200, which is beneficial for correcting spherical aberration and chromatic aberration. The sixth lens 160 is further arranged to adopt a spherical lens, so that the final compensation and correction can be performed on the residual aberration of the fixed-focus lens, and the imaging quality is improved.
In a possible embodiment, the refractive index of the fifth lens 150 is ND5, the abbe constant of the fifth lens 150 is VD5, the refractive index of the sixth lens 160 is ND6, and the abbe constant of the sixth lens 160 is VD6, where ND5 is greater than 1.61 and less than 1.69, ND6 is greater than 1.54 and less than 1.65, VD5 is greater than 18.17 and less than 28.18, and VD6 is greater than 61.28 and less than 80.13.
The refractive index is a ratio of a propagation speed of light in vacuum to a propagation speed of light in the medium, and is mainly used for describing the refractive power of materials to light, and different materials have different refractive indexes, and the higher the refractive index of the material is, the stronger the power for refracting incident light is. The Abbe constant is an index for expressing the dispersion capability of the transparent medium, and the more serious the medium dispersion is, the smaller the Abbe constant is; conversely, the more slight the dispersion of the medium, the greater the Abbe constant.
In the embodiment, by reasonably limiting the refractive index and abbe constant of the fifth lens 150, the correction of spherical aberration and chromatic aberration is facilitated; by reasonably limiting the refractive index and abbe constant of the sixth lens 160, the final compensation and correction can be performed on the residual aberration of the system, and the imaging effect is improved.
As a possible implementation manner, the distance from the optical axis center of the image side surface of the sixth lens 160 to the image surface is BFL, and the distance from the optical axis center of the object side surface of the first lens 110 to the image surface is TTL, wherein BFL/TTL is more than 0.23.
A distance TTL between an optical axis center of an object-side surface of the first lens element 110 and the image plane may be understood as an optical total length of the fixed focus lens, and a distance BFL between an optical axis center of an image-side surface of the sixth lens element 160 and the image plane may be understood as a back focus of the fixed focus lens
As shown in fig. 1, the fixed-focus lens further includes a flat filter 300, the flat filter 300 is located on the image side of the sixth lens element 160, and the flat filter 300 can filter out unwanted stray light, so as to improve the image quality of the fixed-focus lens and ensure that the fixed-focus lens has a good imaging effect both in the daytime and at night, for example, the flat filter 300 filters out infrared light in the daytime to improve the imaging quality of the fixed-focus lens. Meanwhile, the flat filter 300 can also protect the imaging sensor.
In the embodiment, the back focus BFL and the total optical length TTL of the fixed-focus lens are set to satisfy that BFL/TTL is more than 0.23, which is beneficial to ensuring that the flat filter has enough installation space.
As a feasible implementation mode, the distance from the optical axis center of the object side surface of the first lens 110 to the image surface is TTL, the diagonal field angle of the fixed-focus lens is FOV, wherein TTL is less than or equal to 13mm, and FOV is more than or equal to 135 degrees.
In the fixed-focus lens provided in this embodiment, the total optical length TTL is less than or equal to 13mm, and the diagonal field angle FOV is greater than or equal to 135 °, so that an ultrashort wide-angle fixed-focus lens with an ultrashort total optical length and a large field angle is realized.
It is understood that the total optical length TTL and the specific numerical range of the angular field angle FOV are not exclusive and can be set according to practical application requirements, for example, in some embodiments, the angular field angle FOV of the fixed focus lens satisfies 135 ° FOV ≦ 165 °, which is not particularly limited by the embodiments of the present invention.
Specific examples of the fixed focus lens applicable to the above embodiments are further described below with reference to the drawings.
Example one
With reference to fig. 1, a fixed-focus lens according to an embodiment of the present invention includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, and a sixth lens 160, which are sequentially arranged from an object plane to an image plane along an optical axis. The diaphragm 200 is located in the optical path between the third lens 130 and the fourth lens 140, and the flat filter 300 is located on the image side surface side of the sixth lens 160.
Table 1 illustrates in detail specific optical physical parameters of each lens in a fixed focus lens provided by an embodiment of the present invention in a feasible implementation manner, where the fixed focus lens in table 1 corresponds to the fixed focus lens shown in fig. 1.
TABLE 1 design values of optical physical parameters of fixed-focus lens
| Number of noodles | Surface type | Radius of curvature | Thickness of | Refractive index | Abbe constant | Half diameter | k value |
| 1 | Standard noodle | 6.712 | 0.699 | 1.774 | 58.760 | 3.435 | |
| 2 | Standard noodle | 1.917 | 1.731 | 1.867 | |||
| 3 | Standard noodle | -11.729 | 0.700 | 1.677 | 72.188 | 1.811 | |
| 4 | Standard noodle | 2.661 | 0.311 | 1.528 | |||
| 5 | Standard noodle | 3.467 | 1.948 | 1.837 | 41.994 | 1.547 | |
| 6 | Standard noodle | -46.342 | 0.791 | 1.283 | |||
| STO | Standard noodle | Infinite number of elements | -0.205 | 1.098 | |||
| 8 | Aspherical surface | 2.161 | 1.442 | 1.560 | 64.750 | 1.113 | 1.093 |
| 9 | Aspherical surface | -2.477 | 0.028 | 0.970 | -12.105 | ||
| 10 | Aspherical surface | 127.306 | 0.499 | 1.679 | 23.861 | 0.943 | -99.827 |
| 11 | Aspherical surface | 1.825 | 0.327 | 0.988 | -7.243 | ||
| 12 | Standard noodle | 4.992 | 0.966 | 1.638 | 68.201 | 1.254 | |
| 13 | Standard noodle | -5.332 | 1.076 | 1.438 | |||
| 14 | Standard noodle | Infinite number of elements | 0.700 | 1.517 | 64.212 | 1.842 | |
| 15 | Standard noodle | Infinite number of elements | 1.316 | 1.984 | |||
| IMA | Standard noodle | Unlimited in size | 0.000 | 2.401 |
The surface numbers in table 1 are numbered according to the surface order of the lenses, for example, the surface number "1" represents the object side surface of the first lens 110, the surface number "2" represents the image side surface of the first lens 110, and so on; "STO" represents the stop 200 of the fixed focus lens; the curvature radius represents the bending degree of the lens surface, a positive value represents that the surface is bent to the image surface side, and a negative value represents that the surface is bent to the object surface side; the thickness represents the central axial distance from the current surface to the next surface; the refractive index represents the deflection capability of a material between the current surface and the next surface to light, the blank space represents that the current position is air, and the refractive index is 1; abbe constant (also called dispersion coefficient) represents the dispersion characteristic of the material between the current surface and the next surface to light, and blank spaces represent that the current position is air; the half diameter represents the corresponding ray half height on the surface of each lens; the k value is the numerical value of the cone coefficient; IMA stands for image plane.
The aspheric surface formula is as follows, but not limited to the following expression:
wherein Z is the rise of aspheric surface, c is the basic curvature of vertex, k is conic coefficient, r is the radial coordinate perpendicular to optical axis direction, a i Is a coefficient of a higher order term i r 2i High order terms of the aspheric surface.
By way of example, table 2 details aspheric coefficients of the lenses of the first embodiment in a possible implementation.
TABLE 2 designed values of aspherical coefficients of respective lenses in fixed-focus lens
| Number of noodles | a 2 | a 3 | a 4 | a 5 | a 6 | a 7 |
| 8 | -1.5735E-02 | 1.7393E-02 | -2.0373E-02 | 3.5229E-03 | 4.7946E-03 | -2.3925E-03 |
| 9 | 4.0577E-02 | -9.4264E-02 | 1.0384E-01 | -3.6386E-02 | -3.0850E-02 | 2.0566E-02 |
| 10 | -3.6759E-02 | -1.3145E-03 | -3.1891E-02 | -3.0197E-03 | 3.1474E-02 | -1.6883E-02 |
| 11 | 1.2493E-02 | 2.2421E-03 | -4.1373E-03 | -3.8012E-03 | 5.1007E-03 | -1.0411E-03 |
wherein-1.5735E-02 represents a coefficient a with a face number of 8 2 Is-1.5735 x 10 -2 And so on.
The prime lens of the first embodiment achieves the following technical indexes:
TABLE 3 technical index of prime lens
| Total optical length | 12.33mm |
| Angle of |
140° |
Further, fig. 2 is a spherical aberration curve diagram of a fixed focus lens according to an embodiment of the present invention, as shown in fig. 2, a vertical axis is a dimensionless quantity, which represents a normalized entrance pupil radius, an abscissa represents a distance from a surface of an image sensor to a focal point on each wavelength axis, and different wavelengths of system images represented by different linear curves in the diagram are within a range of ± 0.1mm, as can be seen from fig. 2, abscissa values of different wavelengths (0.436 μm, 0.487 μm, 0.546 μm, 0.587 μm, and 0.656 μm) are all within a range of ± 0.1mm, which indicates that axial corrective chromatic aberration of the fixed focus lens is good, and can meet application requirements in fields such as VLOG (video recording) cameras.
Fig. 3 is a field curvature distortion diagram of a prime lens according to a first embodiment of the present invention, as shown in fig. 3, in a left side coordinate system, a horizontal coordinate represents a size of the field curvature, and a unit is mm; the vertical coordinate represents the normalized image height, with no units; wherein T represents meridian and S represents arc loss; as can be seen from fig. 3, the fixed-focus lens provided by this embodiment is effectively controlled in curvature of field, that is, when imaging, the difference between the central image quality and the peripheral image quality is small; in the coordinate system on the right side, the horizontal coordinate represents the magnitude of the distortion in units of%; the vertical coordinate represents the normalized image height, with no units; as can be seen from fig. 3, the field angle of the fixed-focus lens provided by this embodiment reaches 140 °, and the wide-angle application requirements in the fields of VLOG (video recording) cameras and the like are met.
Example two
Fig. 4 is a schematic structural diagram of a fixed focus lens provided by the second embodiment of the present invention, as shown in fig. 4, the second embodiment of the present invention provides a fixed focus lens including a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, and a sixth lens 160 arranged in sequence from an object plane to an image plane along an optical axis. The stop 200 is located in the optical path between the third lens 130 and the fourth lens 140, and the flat filter 300 is located on the image side surface side of the sixth lens 160.
Table 4 illustrates specific optical physical parameters of each lens in the fixed-focus lens provided by embodiment two of the present invention in a practical implementation manner.
TABLE 4 design values of optical physical parameters of fixed-focus lens
The surface numbers in table 4 are numbered according to the surface sequence of each lens, for example, the surface number "1" represents the object side surface of the first lens 110, the surface number "2" represents the image side surface of the first lens 110, and so on; "STO" represents the stop 200 of the fixed focus lens; the curvature radius represents the bending degree of the lens surface, a positive value represents that the surface is bent to the image surface side, and a negative value represents that the surface is bent to the object surface side; thickness represents the central axial distance from the current surface to the next surface; the refractive index represents the deflection capability of a material between the current surface and the next surface to light, the blank space represents that the current position is air, and the refractive index is 1; abbe constant (also called dispersion coefficient) represents the dispersion characteristic of the material between the current surface and the next surface to light, and blank spaces represent that the current position is air; the half diameter represents the corresponding ray half height on the surface of each lens; the k value is the numerical value of the cone coefficient; IMA stands for image plane.
The aspheric surface formula is as follows, but not limited to the following expression:
wherein Z is the rise of the aspheric surface, c is the basic curvature at the vertex, k is the conic coefficient, r is the radial coordinate perpendicular to the optical axis, a i Is a coefficient of a higher order term i r 2i A high order term of an aspheric surface.
Table 5 illustrates aspheric coefficients of each lens in the second embodiment in a possible implementation manner.
TABLE 5 design values of aspherical coefficients of respective lenses in fixed-focus lens
| Noodle sequence number | a 2 | a 3 | a 4 | a 5 | a 6 | a 7 |
| 8 | -2.1909E-02 | 1.5008E-02 | -2.0685E-02 | 3.0794E-03 | 6.0721E-03 | -3.3324E-03 |
| 9 | 3.3930E-02 | -9.4801E-02 | 1.0126E-01 | -4.0917E-02 | -3.2662E-02 | 2.4447E-02 |
| 10 | -3.9086E-02 | 1.4452E-03 | -1.9420E-02 | -2.4911E-03 | 2.7235E-02 | -1.8581E-02 |
| 11 | 5.1904E-03 | 2.4116E-03 | -8.6653E-05 | -2.3949E-03 | 2.1469E-03 | -7.8673E-05 |
wherein-2.1909E-02 represents a coefficient a having a face number of 8 2 Is-2.1909 x 10 -2 And so on.
The fixed-focus lens of the second embodiment achieves the following technical indexes:
TABLE 6 technical index of prime lens
| Total optical length | 12.53mm |
| Angle of |
160° |
Further, fig. 5 is a spherical aberration curve chart of the fixed focus lens provided by the second embodiment of the present invention, as shown in fig. 5, the vertical axis is a dimensionless quantity, and represents a normalized entrance pupil radius, the abscissa represents a distance from the surface of the image sensor to a focal point on each wavelength axis, and different wavelengths of system imaging represented by different linear curves in the graph are within a range of ± 0.1mm, as can be seen from fig. 5, the abscissa values of different wavelengths (0.436 μm, 0.487 μm, 0.546 μm, 0.587 μm, and 0.656 μm) all indicate that the axial chromatic aberration of the fixed focus lens is well corrected, and can meet application requirements in fields such as VLOG (video recording) cameras.
Fig. 6 is a field curvature distortion diagram of a fixed focus lens according to the second embodiment of the present invention, as shown in fig. 6, in a left side coordinate system, a horizontal coordinate represents a size of the field curvature, and a unit is mm; the vertical coordinate represents the normalized image height, with no units; wherein T represents meridian and S represents arc loss; as can be seen from fig. 6, the fixed-focus lens provided by this embodiment is effectively controlled in curvature of field, that is, when imaging, the difference between the central image quality and the peripheral image quality is small; in the right-hand coordinate system, the horizontal coordinate represents the magnitude of distortion in units; the vertical coordinate represents the normalized image height, with no units; as can be seen from fig. 6, the field angle of the fixed focus lens provided in this embodiment reaches 160 °, which meets the wide-angle application requirements in the fields of VLOG (video recording) cameras and the like.
EXAMPLE III
Fig. 7 is a schematic structural diagram of a fixed-focus lens according to a third embodiment of the present invention, as shown in fig. 7, the fixed-focus lens according to the third embodiment of the present invention includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, and a sixth lens 160, which are sequentially arranged from an object plane to an image plane along an optical axis. The diaphragm 200 is located in the optical path between the third lens 130 and the fourth lens 140, and the flat filter 300 is located on the image side surface side of the sixth lens 160.
Table 7 illustrates specific optical physical parameters of each lens in the fixed focus lens provided by the third embodiment of the present invention in detail in an exemplary practical implementation manner.
TABLE 7 design values of optical physical parameters of fixed-focus lens
| Number of noodles | Surface type | Radius of curvature | Thickness of | Refractive index | Abbe number | Half diameter | Value of K |
| 1 | Standard noodle | 17.265 | 1.186 | 1.767 | 51.404 | 3.621 | |
| 2 | Standard noodle | 1.931 | 1.366 | 1.788 | |||
| 3 | Standard noodle | 210.000 | 0.700 | 1.667 | 55.360 | 1.730 | |
| 4 | Standard noodle | 2.954 | 0.402 | 1.507 | |||
| 5 | Standard noodle | 4.081 | 2.076 | 1.784 | 31.000 | 1.521 | |
| 6 | Standard noodle | -29.325 | 0.700 | 1.270 | |||
| STO | Standard noodle | Unlimited in size | -0.289 | 1.167 | |||
| 8 | Aspherical surface | 2.141 | 1.530 | 1.543 | 66.740 | 1.181 | 1.176 |
| 9 | Aspherical surface | -2.381 | 0.050 | 0.990 | -10.820 | ||
| 10 | Aspherical surface | -7.455 | 0.523 | 1.636 | 26.480 | 0.961 | 19.555 |
| 11 | Aspherical surface | 2.024 | 0.219 | 0.984 | -7.427 | ||
| 12 | Standard noodle | 4.354 | 0.974 | 1.638 | 78.680 | 1.174 | |
| 13 | Standard noodle | -4.964 | 1.384 | 1.361 | |||
| 14 | Standard noodle | Unlimited in size | 0.700 | 1.517 | 64.212 | 1.850 | |
| 15 | Standard noodle | Infinite number of elements | 1.316 | 1.990 | |||
| IMA | Standard noodle | Unlimited in size | 2.400 |
The surface numbers in table 7 are numbered according to the surface order of the lenses, for example, the surface number "1" represents the object side surface of the first lens 110, the surface number "2" represents the image side surface of the first lens 110, and so on; "STO" represents the stop 200 of the fixed focus lens; the curvature radius represents the bending degree of the lens surface, a positive value represents that the surface is bent to the image surface side, and a negative value represents that the surface is bent to the object surface side; thickness represents the central axial distance from the current surface to the next surface; the refractive index represents the deflection capability of a material between the current surface and the next surface to light, the blank space represents that the current position is air, and the refractive index is 1; abbe constant (also called dispersion coefficient) represents the dispersion characteristic of the material between the current surface and the next surface to light, and blank spaces represent that the current position is air; the half diameter represents the corresponding ray half height on the surface of each lens; the k value is the numerical value of the cone coefficient; IMA stands for image plane.
The aspheric surface formula is as follows, but is not limited to the following expression:
wherein Z is the rise of aspheric surface, c is the basic curvature of vertex, k is conic coefficient, r is the radial coordinate perpendicular to optical axis direction, a i Is a coefficient of a higher order term i r 2i A high order term of an aspheric surface.
Table 8 illustrates aspheric coefficients of each lens in the third embodiment in a possible embodiment.
TABLE 8 designed values of aspheric coefficients of lenses in fixed focus lens
| Number of noodles | a 2 | a 3 | a 4 | a 5 | a 6 | a 7 |
| 8 | -1.3382E-02 | 1.8693E-02 | -2.1044E-02 | 2.7592E-03 | 6.3013E-03 | -2.9879E-03 |
| 9 | 4.0243E-02 | -9.0404E-02 | 1.0763E-01 | -3.4466E-02 | -3.1612E-02 | 1.7362E-02 |
| 10 | -2.9412E-02 | 2.0005E-03 | -2.4923E-02 | -3.8733E-03 | 2.8828E-02 | -2.0192E-02 |
| 11 | 7.5454E-03 | 3.4979E-03 | -1.4588E-03 | -2.1564E-03 | 4.7657E-03 | -2.4984E-03 |
wherein-1.3382E-02 represents a coefficient a having a face number of 8 2 Is-1.3382 x 10 -2 And so on.
The fixed-focus lens in the third embodiment achieves the following technical indexes:
TABLE 9 technical indexes of prime lens
| Total optical length | 12.84mm |
| Angle of |
150° |
Further, fig. 8 is a spherical aberration curve diagram of a fixed-focus lens provided by the third embodiment of the present invention, as shown in fig. 8, a vertical axis is a dimensionless quantity, which represents a normalized entrance pupil radius, an abscissa represents a distance from the surface of the image sensor to a focal point on each wavelength axis, and different wavelengths of system imaging represented by different linear curves in the diagram are within ± 0.1mm, as can be seen from fig. 5, abscissa values of different wavelengths (0.436 μm, 0.487 μm, 0.546 μm, 0.587 μm, and 0.656 μm) are all within a range of ± 0.1mm, which indicates that axial chromatic aberration of the fixed-focus lens is well corrected, and can meet application requirements in fields such as VLOG (video recording) cameras.
Fig. 9 is a distortion diagram of the field curvature of the prime lens according to the third embodiment of the present invention, as shown in fig. 9, in the left coordinate system, the horizontal coordinate represents the size of the field curvature, and the unit is mm; the vertical coordinate represents the normalized image height, with no units; wherein T represents meridian and S represents arc loss; as can be seen from fig. 9, the fixed focus lens provided in this embodiment is effectively controlled in curvature of field, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the right-hand coordinate system, the horizontal coordinate represents the magnitude of distortion in units; the vertical coordinate represents the normalized image height, with no units; as can be seen from fig. 9, the field angle of the fixed-focus lens provided by this embodiment reaches 150 °, and the wide-angle application requirements in the fields of VLOG (video recording) cameras and the like are met.
The above detailed description does not limit the scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made in accordance with design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A fixed focus lens is characterized by comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object plane to an image plane along an optical axis;
the first lens has a negative optical power, the second lens has a negative optical power, and the third lens has a positive optical power; the fourth lens has a positive optical power, the fifth lens has a negative optical power, and the sixth lens has a positive optical power;
the focal power of the first lens is phi 1, the focal power of the third lens is phi 3, the focal power of the fifth lens is phi 5, the focal power of the sixth lens is phi 6, and the focal power of the prime lens is phi, wherein-0.674 < phi 1/phi < -0.506,0.393 < phi 3/phi < 0.503, -0.801 < phi 5/phi < -0.689,0.411 < phi 6/phi < 0.518;
the curvature of the object side surface of the first lens is C1, the curvature of the image side surface of the first lens is C2, wherein the ratio of (C1-C2)/(C1 + C2) is more than or equal to-1.808 and less than or equal to-1.132;
the maximum clear aperture of the first lens is D1, the distance from the optical axis center of the object side surface of the first lens to the image surface is TTL, and D1/TTL is less than 0.57.
2. The prime lens according to claim 1,
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 image side surface of the second lens is a concave surface;
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;
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 image side surface of the fifth lens is a concave surface;
the object side surface of the sixth lens element is a convex surface, and the image side surface of the sixth lens element is a convex surface.
3. The prime lens according to claim 1,
the fixed-focus lens further comprises a diaphragm;
the diaphragm is located in an optical path between the third lens and the fourth lens.
4. The prime lens according to claim 1,
the first lens, the second lens, the third lens and the sixth lens are glass lenses, and the fourth lens and the fifth lens are plastic lenses.
5. The prime lens according to claim 1,
the first lens, the second lens and the third lens are all spherical lenses.
6. The prime lens according to claim 1,
the refractive index of the first lens is ND1, the refractive index of the second lens is ND2, the refractive index of the third lens is ND3, wherein ND1 is more than 1.64 and less than 1.78, ND2 is more than 1.58 and less than 1.69, and ND3 is more than 1.77 and less than 1.85.
7. The prime lens according to claim 1,
the fifth lens is an aspheric lens, and the sixth lens is a spherical lens.
8. The prime lens according to claim 1,
the refractive index of the fifth lens is ND5, the Abbe constant of the fifth lens is VD5, the refractive index of the sixth lens is ND6, and the Abbe constant of the sixth lens is VD6, wherein ND5 is more than 1.61 and less than 1.69, ND6 is more than 1.54 and less than 1.65, VD5 is more than 18.17 and less than 28.18, and VD6 is more than 61.28 and less than 80.13.
9. The prime lens according to claim 1,
the distance from the optical axis center of the image side surface of the sixth lens to the image surface is BFL, the distance from the optical axis center of the object side surface of the first lens to the image surface is TTL, and the BFL/TTL is greater than 0.23.
10. The prime lens according to claim 1,
the distance from the center of an optical axis of the object side surface of the first lens to the image surface is TTL, the diagonal field angle of the fixed-focus lens is FOV, wherein the TTL is less than or equal to 13mm, and the FOV is more than or equal to 135 degrees.
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| CN202222879175.7U CN218497251U (en) | 2022-10-31 | 2022-10-31 | Fixed focus lens |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202222879175.7U CN218497251U (en) | 2022-10-31 | 2022-10-31 | Fixed focus lens |
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| CN218497251U true CN218497251U (en) | 2023-02-17 |
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