CN216210193U - Fixed focus lens - Google Patents

Fixed focus lens Download PDF

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CN216210193U
CN216210193U CN202122723730.2U CN202122723730U CN216210193U CN 216210193 U CN216210193 U CN 216210193U CN 202122723730 U CN202122723730 U CN 202122723730U CN 216210193 U CN216210193 U CN 216210193U
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lens
focal power
fixed
focus lens
image
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刘峥嵘
张磊
张占军
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Dongguan Yutong Optical Technology Co Ltd
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Dongguan Yutong Optical Technology Co Ltd
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Abstract

The embodiment of the utility model discloses a fixed-focus lens. The lens comprises a first lens with negative focal power, a second lens with positive focal power or negative focal power, a third lens with positive focal power or negative focal power, a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power and a seventh lens with positive focal power, wherein the first lens with negative focal power, the second lens with positive focal power or negative focal power, the third lens with positive focal power or negative focal power, the fourth lens with positive focal power, the fifth lens with positive focal power, the sixth lens with negative focal power and the seventh lens with positive focal power are sequentially arranged along an optical axis from an object side to an image side; the diaphragm is positioned between the second lens and the third lens or between the third lens and the fourth lens; the fourth lens is a spherical lens, and the first lens, the second lens, the third lens, the fifth lens, the sixth lens and the seventh lens are all aspheric lenses. The technical scheme of the utility model can realize the requirements on large target surface and ultra-large aperture of the lens, supports the maximum target surface of 1/1.7 inch under the condition of lower cost, has the F number of more than or equal to 0.8 and less than or equal to 1.2, has the field angle of more than 110 degrees, and meets the imaging requirement when used in the environment of minus 40-80 ℃.

Description

Fixed focus lens
Technical Field
The embodiment of the utility model relates to a lens technology, in particular to a fixed-focus lens.
Background
With the development of society, the application range and the scene of the security monitoring video technology are gradually expanded, and the requirements of security monitoring on the aspects of high-definition, intellectualization, networking and the like are increasingly strengthened.
With the increasing development of security monitoring systems, the requirements on security lenses are higher and higher, and the requirements are mainly embodied in higher image quality, larger clear aperture, larger view field and larger target surface. The existing lens with the ultra-large aperture is usually low in image quality, and the target surface is generally 1/2.7 inch. Therefore, it is necessary to develop a large target surface and large aperture 4K optical lens in order to solve the conventional phenomenon.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a fixed focus lens, which meets the requirements of large target surface and an ultra-large aperture of the lens, supports 1/1.7 inch of the maximum target surface under the condition of low cost, has the aperture number of 0.8-1.2, the F angle of more than 110 degrees and meets the imaging requirements when used in an environment of-40-80 ℃.
The embodiment of the utility model provides a fixed-focus lens, which comprises a first lens with negative focal power, a second lens with positive focal power or negative focal power, a third lens with positive focal power or negative focal power, a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power and a seventh lens with positive focal power, wherein the first lens with negative focal power, the second lens with positive focal power or negative focal power, the third lens with positive focal power or negative focal power, the fourth lens with positive focal power, the fifth lens with positive focal power, the sixth lens with negative focal power and the seventh lens with positive focal power are sequentially arranged along an optical axis from an object space to an image space;
the fixed-focus lens further comprises a diaphragm, and the diaphragm is positioned between the second lens and the third lens or between the third lens and the fourth lens;
the fourth lens is a spherical lens, and the first lens, the second lens, the third lens, the fifth lens, the sixth lens and the seventh lens are aspheric lenses.
Optionally, the surface that first lens is close to object side is the convex surface, and the surface that is close to image side one side is the concave surface, the surface that the second lens is close to object side one side is the concave surface, and the surface that is close to image side one side is the convex surface, the surface that the third lens is close to object side one side is the convex surface, and the surface that is close to image side one side is the concave surface, two surfaces of fourth lens are the convex surface, two surfaces of fifth lens are the convex surface, the surface that the sixth lens is close to object side one side is the concave surface, and the surface that is close to image side one side is concave surface or convex surface, the surface that the seventh lens is close to object side one side is the convex surface, and the surface that is close to image side one side is convex surface or concave surface.
Optionally, the optical powers of the first lens to the seventh lens satisfy:
Figure BDA0003342087250000021
Figure BDA0003342087250000022
Figure BDA0003342087250000023
Figure BDA0003342087250000024
Figure BDA0003342087250000025
Figure BDA0003342087250000026
Figure BDA0003342087250000027
wherein the content of the first and second substances,
Figure BDA0003342087250000028
and
Figure BDA0003342087250000029
respectively represent the optical powers of the first lens to the seventh lens,
Figure BDA00033420872500000210
representing the focal power of the fixed focus lens.
Optionally, the refractive index and the abbe number of the first lens to the seventh lens satisfy:
1.50≤n1≤1.60；50.0≤v1≤65.0；
1.50≤n2≤1.75；20.0≤v2≤65.0；
1.50≤n3≤1.70；18.0≤v3≤25.0；
1.49≤n4≤1.70；60.0≤v4≤75.0；
1.50≤n5≤1.60；50.0≤v5≤75.0；
1.60≤n6≤1.75；15.0≤v6≤25.0；
1.50≤n7≤1.60；50.0≤v7≤60.0；
wherein n1, n2, n3, n4, n5, n6 and n7 sequentially represent refractive indices of the first to seventh lenses, respectively, and v1, v2, v3, v4, v5, v6 and v7 sequentially represent abbe numbers of the first to seventh lenses, respectively.
Optionally, the focal length f and the entrance pupil diameter d of the fixed-focus lens satisfy:
0.8≤f/d≤1.2。
optionally, the focal length f and the image plane diameter IC of the fixed-focus lens satisfy:
0.29≤f/IC≤0.9。
optionally, the image plane diameter IC of the fixed-focus lens satisfies:
8.5mm≤IC≤9.6mm。
optionally, the back focus BFL of the fixed focus lens and the total lens length TTL satisfy:
BFL/TTL≥0.1。
optionally, the diameter D1 of the first lens and the total lens length TTL satisfy:
D1/TTL<0.5。
optionally, an F-number F of the fixed-focus lens satisfies:
0.8≤F≤1.2。
the fixed focus lens provided by the embodiment of the utility model comprises a first lens with negative focal power, a second lens with positive focal power or negative focal power, a third lens with positive focal power or negative focal power, a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power and a seventh lens with positive focal power, which are sequentially arranged from an object space to an image space along an optical axis; the diaphragm is positioned between the second lens and the third lens or between the third lens and the fourth lens; the fourth lens is a spherical lens, and the first lens, the second lens, the third lens, the fifth lens, the sixth lens and the seventh lens are all aspheric lenses. The first lens with negative focal power is beneficial to the collection of light rays of an optical system, and the monitoring field range can be effectively enlarged; the fourth lens with positive focal power bears larger focal power of the system, changes the propagation direction of the light beam and is more favorable for imaging the light beam on an image surface; by comprehensively setting the matching relationship of focal power and shape of each lens, various aberrations such as spherical aberration, chromatic aberration, field curvature, astigmatism, distortion and the like of the system can be effectively corrected, so that the requirements on large target surface and ultra-large aperture of the lens are realized, the prime focus lens supports the maximum target surface of 1/1.7 inch under the condition of low cost, the F is more than or equal to 0.8 and less than or equal to 1.2, the field angle is more than 110 degrees, and the imaging requirements are met when the prime focus lens is used in the environment of-40-80 ℃.
Drawings
Fig. 1 is a schematic structural diagram of a fixed focus lens according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a spherical aberration curve of a fixed-focus lens according to an embodiment of the present invention;
fig. 3 is a schematic view of a light fan of a fixed focus lens according to an embodiment of the present invention;
fig. 4 is a schematic diagram illustrating distortion of a field region of a fixed focus lens according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of another fixed-focus lens provided in the embodiment of the present invention;
fig. 6 is a schematic diagram of a spherical aberration curve of a fixed-focus lens according to an embodiment of the present invention;
fig. 7 is a light fan schematic diagram of a fixed focus lens according to an embodiment of the present invention;
fig. 8 is a schematic diagram illustrating distortion of a field region of a fixed focus lens according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of another fixed-focus lens provided in the embodiment of the present invention;
fig. 10 is a schematic diagram of a spherical aberration curve of a fixed-focus lens according to an embodiment of the present invention;
fig. 11 is a light fan schematic diagram of a fixed focus lens according to an embodiment of the present invention;
fig. 12 is a schematic diagram illustrating distortion of a field region of a fixed focus lens according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting of the utility model. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
The terminology used in the embodiments of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. It should be noted that the terms "upper", "lower", "left", "right", and the like used in the description of the embodiments of the present invention are used in the angle shown in the drawings, and should not be construed as limiting the embodiments of the present invention. In addition, in this context, it is also to be understood that when an element is referred to as being "on" or "under" another element, it can be directly formed on "or" under "the other element or be indirectly formed on" or "under" the other element through an intermediate element. The terms "first," "second," and the like, are used for descriptive purposes only and not for purposes of limitation, and do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Fig. 1 is a schematic structural diagram of a fixed-focus lens according to an embodiment of the present invention. Referring to fig. 1, the fixed focus lens provided by the embodiment of the present invention includes a first lens 10 with negative power, a second lens 20 with positive power or negative power, a third lens 30 with positive power or negative power, a fourth lens 40 with positive power, a fifth lens 50 with positive power, a sixth lens 60 with negative power, and a seventh lens 70 with positive power, which are arranged in this order from the object side to the image side along the optical axis; the prime lens further comprises a diaphragm (not shown in fig. 1) located between the second lens 20 and the third lens 30 or between the third lens 30 and the fourth lens 40; the fourth lens 40 is a spherical lens, and the first lens 10, the second lens 20, the third lens 30, the fifth lens 50, the sixth lens 60, and the seventh lens 70 are all aspheric lenses.
Therein, it is understood that the optical power is equal to the difference between the image-side and object-side convergence, which characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal power is, the stronger the bending ability to the light ray is, and the smaller the absolute value of the focal power is, the weaker the bending ability 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 the embodiment, each lens can be fixed in a lens barrel (not shown in fig. 1), and the lens can have the characteristics of a large target surface and a large aperture by reasonably distributing the focal power of the lens, wherein the aperture value F satisfies 0.8 ≤ F ≤ 1.2, and supports an image surface of 1/1.7 inch, and the field angle is greater than 110 °.
According to the technical scheme of the embodiment, the first lens with negative focal power is arranged, so that the collection of light rays of an optical system is facilitated, and the monitoring field range can be effectively enlarged; the fourth lens with positive focal power bears larger focal power of the system, changes the propagation direction of the light beam and is more favorable for imaging the light beam on an image surface; by comprehensively setting the matching relationship of focal power and shape of each lens, various aberrations such as spherical aberration, chromatic aberration, field curvature, astigmatism, distortion and the like of the system can be effectively corrected, so that the requirements on large target surface and ultra-large aperture of the lens are realized, the prime focus lens supports the maximum target surface of 1/1.7 inch under the condition of low cost, the F is more than or equal to 0.8 and less than or equal to 1.2, the field angle is more than 110 degrees, and the imaging requirements are met when the prime focus lens is used in the environment of-40-80 ℃.
On the basis of the above technical solution, with reference to fig. 1, optionally, the surface of the first lens element 10 close to the object side is a convex surface, the surface close to the image side is a concave surface, the surface of the second lens element 20 close to the object side is a concave surface, the surface close to the image side is a convex surface, the surface of the third lens element 30 close to the object side is a convex surface, the surface close to the image side is a concave surface, both surfaces of the fourth lens element 40 are convex surfaces, both surfaces of the fifth lens element 50 are convex surfaces, the surface of the sixth lens element 60 close to the object side is a concave surface, the surface close to the image side is a concave surface or a convex surface, the surface of the seventh lens element 70 close to the object side is a convex surface, and the surface close to the image side is a convex surface or a concave surface. That is, the first lens 10 is a convex-concave lens, the second lens 20 is a concave-convex lens, the third lens 30 is a convex-concave lens, the fourth lens 40 is a double-convex lens, the fifth lens 50 is a double-convex lens, the sixth lens 60 is a double-concave or convex-concave lens, and the seventh lens 70 is a double-convex or convex-concave lens.
Alternatively, the optical powers of the first lens 10 to the seventh lens 70 satisfy:
Figure BDA0003342087250000071
Figure BDA0003342087250000072
Figure BDA0003342087250000073
Figure BDA0003342087250000074
Figure BDA0003342087250000075
Figure BDA0003342087250000076
Figure BDA0003342087250000077
wherein the content of the first and second substances,
Figure BDA0003342087250000078
and
Figure BDA0003342087250000079
respectively represent the optical powers of the first lens 10 to the seventh lens 70,
Figure BDA00033420872500000710
representing the focal power of the fixed focus lens. The focal power of each lens meets the relationship, so that the fixed-focus lens can achieve a clear imaging effect.
Alternatively, the refractive index and the abbe number of the first lens 10 to the seventh lens 70 satisfy:
1.50≤n1≤1.60；50.0≤v1≤65.0；
1.50≤n2≤1.75；20.0≤v2≤65.0；
1.50≤n3≤1.70；18.0≤v3≤25.0；
1.49≤n4≤1.70；60.0≤v4≤75.0；
1.50≤n5≤1.60；50.0≤v5≤75.0；
1.60≤n6≤1.75；15.0≤v6≤25.0；
1.50≤n7≤1.60；50.0≤v7≤60.0；
wherein n1, n2, n3, n4, n5, n6 and n7 sequentially represent refractive indices of the first lens 10 to the seventh lens 70, respectively, and v1, v2, v3, v4, v5, v6 and v7 sequentially represent abbe numbers of the first lens 10 to the seventh lens 70, respectively.
Optionally, the focal length f and the entrance pupil diameter d of the fixed-focus lens satisfy:
f/d is more than or equal to 0.8 and less than or equal to 1.2. When f and d satisfy the above-mentioned relation, the tight shot has the characteristic of super large light ring, still can have good imaging effect in the environment of low illumination, can satisfy the imaging demand of light and shade environment.
Optionally, the focal length f and the image plane diameter IC of the fixed-focus lens satisfy:
f/IC is more than or equal to 0.29 and less than or equal to 0.9. When f and the IC meet the relationship, the fixed-focus lens has wide-angle performance, the shooting range of the fixed-focus lens can be ensured, and the system has a larger visual field.
Optionally, the image plane diameter IC of the fixed-focus lens satisfies:
IC is more than or equal to 8.5mm and less than or equal to 9.6 mm. When the IC meets the relationship, the fixed-focus lens has a larger target surface, so that the fixed-focus lens can have better imaging quality and a clearer picture.
Optionally, the back focus BFL of the fixed focus lens and the total lens length TTL satisfy:
BFL/TTL is more than or equal to 0.1. When BFL and TTL satisfy the above relation, it can ensure enough installation space for imaging sensor and flat filter.
Optionally, the diameter D1 of the first lens and the total lens length TTL satisfy:
D1/TTL < 0.5. When the D1 and the TTL meet the relation, the overlarge caliber of the lens can be avoided, and the requirement of the installation space of a final product is met.
The prime lens provided by the embodiment adopts a mixed structure design of one spherical lens and six aspheric surfaces, and the aspheric lens has good aberration correction capability through reasonable arrangement of focal power, refractive index and dispersion coefficient, so that the performance of an optical system is ensured, and the cost is effectively controlled. The lens has the characteristics of low cost, high performance, large aperture and large field angle, can be matched with a 1/1.7-inch photosensitive chip to the maximum extent, has the field angle larger than 110 degrees, and meets the imaging requirements under various application scenes.
Optionally, the surface type of the aspheric lens satisfies the formula:
Figure BDA0003342087250000091
wherein Z represents the axial rise of the aspheric surface in the Z direction; y represents the height of the aspheric surface; c represents the curvature of the fitted sphere, the numerical value is the reciprocal of the radius of curvature, k represents a conic coefficient, and A, B, C, D, E, F represents a high-order aspheric coefficient.
Exemplarily, table 1 shows specific parameters of the fixed-focus lens corresponding to fig. 1:
TABLE 1 specific parameters of prime lens
Figure BDA0003342087250000092
Figure BDA0003342087250000101
The focal length F of the fixed-focus lens in this embodiment is 5.1mm, the aperture value F is 0.95, the image plane diameter is 9.2mm, and the diagonal angle of view is 120 °.
Table 2 shows a design value of the fixed-focus lens provided in table 1:
TABLE 2 design value of prime lens
Figure BDA0003342087250000102
Figure BDA0003342087250000111
The surface numbers in table 2 are numbered in accordance with the order of the surfaces of the respective lenses, where "1" represents the front surface (surface on the object side) of the first lens 10, "2" represents the rear surface (surface on the image side) of the first lens 10, and so on. 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, a negative value represents that the surface is bent to the object surface side, wherein 'infinite' represents that the surface is a plane, and the curvature radius is infinite; thickness represents the central axial distance from the current surface to the next surface, refractive index represents the ability of the material between the current surface and the next surface to deflect light, blank space represents that the current position is air, refractive indices of 1, "16" and "17" represent the two surfaces of the filter, and "18" represents the image plane.
Wherein, table 3 shows the aspheric surface type parameters in this embodiment:
TABLE 3 design value of aspheric surface coefficient in fixed focus lens
Figure BDA0003342087250000112
Figure BDA0003342087250000121
wherein-1.397276E-03 represents that the coefficient A with the face number of 1 is-1.397276X 10-3。
Fig. 2 is a schematic view of a spherical aberration curve of a fixed focus lens according to an embodiment of the present invention, fig. 3 is a schematic view of a light fan of a fixed focus lens according to an embodiment of the present invention, and fig. 4 is a schematic view of a field distortion of a fixed focus lens according to an embodiment of the present invention, where as can be seen from fig. 2 to fig. 4, the fixed focus lens according to the embodiment of the present invention has a good imaging capability.
Fig. 5 is a schematic structural diagram of another fixed-focus lens provided in an embodiment of the present invention, and similar to the above embodiment, table 4 shows specific parameters of the fixed-focus lens corresponding to fig. 5:
TABLE 4 specific parameters of prime lens
Figure BDA0003342087250000122
Figure BDA0003342087250000131
The focal length F of the fixed-focus lens of this embodiment is 4.8mm, the aperture value F is 1.0, the image plane diameter is 9.2mm, and the diagonal angle of view is 118 °.
Table 5 shows a design value of the fixed-focus lens provided in table 4:
TABLE 5 design value of prime lens
Figure BDA0003342087250000132
Figure BDA0003342087250000141
The surface numbers in table 5 are numbered in accordance with the order of the surfaces of the respective lenses, where "1" represents the front surface (surface on the object side) of the first lens 10, "2" represents the rear surface (surface on the image side) of the first lens 10, and so on. 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, a negative value represents that the surface is bent to the object surface side, wherein 'infinite' represents that the surface is a plane, and the curvature radius is infinite; thickness represents the central axial distance from the current surface to the next surface, refractive index represents the ability of the material between the current surface and the next surface to deflect light, blank space represents that the current position is air, refractive indices of 1, "16" and "17" represent the two surfaces of the filter, and "18" represents the image plane.
Wherein, table 6 shows the aspheric surface type parameters in this embodiment:
TABLE 6 design value of aspheric surface coefficient in fixed-focus lens
Figure BDA0003342087250000142
Figure BDA0003342087250000151
wherein-3.208228E-03 represents that the coefficient A with the face number of 1 is-3.208228X 10-3。
Fig. 6 is a schematic view of a spherical aberration curve of a fixed focus lens according to an embodiment of the present invention, fig. 7 is a schematic view of a light fan of a fixed focus lens according to an embodiment of the present invention, and fig. 8 is a schematic view of a field distortion of a fixed focus lens according to an embodiment of the present invention, where as can be seen from fig. 6 to 8, the fixed focus lens according to the embodiment of the present invention has a good imaging capability.
Fig. 9 is a schematic structural diagram of another fixed-focus lens provided in an embodiment of the present invention, and similar to the embodiment, table 7 shows specific parameters of the fixed-focus lens corresponding to fig. 9:
TABLE 7 specific parameters of prime lenses
Figure BDA0003342087250000161
The focal length F of the fixed-focus lens of this embodiment is 4.8mm, the aperture value F is 0.96, the image plane diameter is 9.2mm, and the diagonal angle of view is 118 °.
Table 8 shows a design value of the fixed-focus lens provided in table 7:
TABLE 8 design value of prime lens
Figure BDA0003342087250000162
Figure BDA0003342087250000171
The surface numbers in table 8 are numbered in accordance with the order of the surfaces of the respective lenses, where "1" represents the front surface (surface on the object side) of the first lens 10, "2" represents the rear surface (surface on the image side) of the first lens 10, and so on. 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, a negative value represents that the surface is bent to the object surface side, wherein 'infinite' represents that the surface is a plane, and the curvature radius is infinite; thickness represents the central axial distance from the current surface to the next surface, refractive index represents the ability of the material between the current surface and the next surface to deflect light, blank space represents that the current position is air, refractive indices of 1, "16" and "17" represent the two surfaces of the filter, and "18" represents the image plane.
Wherein, table 9 is the aspheric surface type parameter in this embodiment:
TABLE 9 design value of aspheric coefficient in fixed-focus lens
Figure BDA0003342087250000181
Figure BDA0003342087250000191
wherein-4.599183E-03 represents that the coefficient A with the face number of 1 is-4.599183X 10-3。
Fig. 10 is a schematic view of a spherical aberration curve of a fixed focus lens according to an embodiment of the present invention, fig. 11 is a schematic view of a light fan of a fixed focus lens according to an embodiment of the present invention, and fig. 12 is a schematic view of a field distortion of a fixed focus lens according to an embodiment of the present invention, where as can be seen from fig. 10 to 12, the fixed focus lens according to the embodiment of the present invention has a good imaging capability.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the utility model. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (10)

1. A fixed focus lens is characterized by comprising a first lens with negative focal power, a second lens with positive focal power or negative focal power, a third lens with positive focal power or negative focal power, a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power and a seventh lens with positive focal power, which are sequentially arranged from an object side to an image side along an optical axis;
the fixed-focus lens further comprises a diaphragm, and the diaphragm is positioned between the second lens and the third lens or between the third lens and the fourth lens;
the fourth lens is a spherical lens, and the first lens, the second lens, the third lens, the fifth lens, the sixth lens and the seventh lens are aspheric lenses.
2. The fixed-focus lens system as claimed in claim 1, wherein the first lens element has a convex surface on a side close to the object, a concave surface on a side close to the image, a concave surface on a side close to the object, a convex surface on a side close to the image, a convex surface on a side close to the object, a concave surface on a side close to the image, two convex surfaces on the fourth lens element, two convex surfaces on the fifth lens element, a concave surface on a side close to the object, a concave surface on a side close to the image, a concave surface or a convex surface on a side close to the image, a convex surface on a side close to the object, and a convex surface or a concave surface on a side close to the image.
3. The prime lens according to claim 1, wherein optical powers of the first lens to the seventh lens satisfy:
Figure FDA0003342087240000011
Figure FDA0003342087240000012
Figure FDA0003342087240000013
Figure FDA0003342087240000014
Figure FDA0003342087240000015
Figure FDA0003342087240000021
Figure FDA0003342087240000022
wherein the content of the first and second substances,
Figure FDA0003342087240000023
and
Figure FDA0003342087240000024
respectively represent the optical powers of the first lens to the seventh lens,
Figure FDA0003342087240000025
representing the focal power of the fixed focus lens.
4. The prime lens according to claim 1, wherein the refractive index and the abbe number of the first lens to the seventh lens satisfy:
1.50≤n1≤1.60；50.0≤v1≤65.0；
1.50≤n2≤1.75；20.0≤v2≤65.0；
1.50≤n3≤1.70；18.0≤v3≤25.0；
1.49≤n4≤1.70；60.0≤v4≤75.0；
1.50≤n5≤1.60；50.0≤v5≤75.0；
1.60≤n6≤1.75；15.0≤v6≤25.0；
1.50≤n7≤1.60；50.0≤v7≤60.0；
wherein n1, n2, n3, n4, n5, n6 and n7 sequentially represent refractive indices of the first to seventh lenses, respectively, and v1, v2, v3, v4, v5, v6 and v7 sequentially represent abbe numbers of the first to seventh lenses, respectively.
5. The fixed focus lens according to claim 1, wherein a focal length f and an entrance pupil diameter d of the fixed focus lens satisfy:
0.8≤f/d≤1.2。
6. the fixed focus lens according to claim 1, wherein a focal length f and an image plane diameter IC of the fixed focus lens satisfy:
0.29≤f/IC≤0.9。
7. the fixed focus lens according to claim 1, wherein an image plane diameter IC of the fixed focus lens satisfies:
8.5mm≤IC≤9.6mm。
8. the fixed-focus lens according to claim 1, wherein a back focus BFL and a total lens length TTL of the fixed-focus lens satisfy:
BFL/TTL≥0.1。
9. the fixed focus lens as claimed in claim 1, wherein the diameter D1 of the first lens element and the total lens length TTL satisfy:
D1/TTL<0.5。
10. a prime lens according to any one of claims 1 to 9, wherein the F-number F of the prime lens satisfies:
0.8≤F≤1.2。
CN202122723730.2U 2021-11-08 2021-11-08 Fixed focus lens Active CN216210193U (en)

Priority Applications (1)

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Application Number Priority Date Filing Date Title
CN202122723730.2U CN216210193U (en) 2021-11-08 2021-11-08 Fixed focus lens

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CN216210193U true CN216210193U (en) 2022-04-05

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