CN114647070B - Optical system - Google Patents
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- CN114647070B CN114647070B CN202210305624.9A CN202210305624A CN114647070B CN 114647070 B CN114647070 B CN 114647070B CN 202210305624 A CN202210305624 A CN 202210305624A CN 114647070 B CN114647070 B CN 114647070B
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/02—Telephoto objectives, i.e. systems of the type + - in which the distance from the front vertex to the image plane is less than the equivalent focal length
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
- G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
- G02B13/0045—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having five or more lenses
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
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Abstract
The embodiment of the application provides an optical system, wherein a second lens group and a first lens group are sequentially arranged from an object side to an image side in the optical system; the optical axes of the lenses in the second lens group are overlapped; the first lens group comprises at least one lens, and the optical center of the lens is offset relative to the optical axis of the second lens group and/or the optical axis of the lens is deflected from the optical axis of the second lens group; the focal length of the lens is larger than a preset focal length threshold, and the difference degree between the focal length of the second lens group and the focal length of the optical system is smaller than the preset difference threshold. The lens which can shoot high-quality images under the conditions of long focal length, large aperture and wide depth of field can be designed.
Description
Technical Field
The application relates to the technical field of optics, in particular to an optical system.
Background
For a long-focus lens, if the aperture is larger and the image plane is larger, the aperture of the lens is larger, and the aberration of an object positioned at the edge of the field of view is harder to correct; meanwhile, as the focal length is longer, the degree of deviation of the positions of the image planes when the images formed by different object distances are clear from the focusing is larger, namely, the smaller the range of the scene depth is, the quality of the shot image is affected.
How to design a lens with long focus and large aperture expansion depth of field so as to improve the quality of a shot image becomes a technical problem to be solved.
Disclosure of Invention
An object of an embodiment of the present application is to provide an optical system for designing a lens capable of capturing high-quality images with a long focal length, a large aperture, and a wide depth of field. The specific technical scheme is as follows:
the embodiment of the application provides an optical system with long focus and large aperture expansion depth of field, wherein a first lens group and a second lens group are sequentially arranged from an object direction image side in the optical system;
the optical axes of the lenses in the second lens group are overlapped;
the first lens group comprises at least one lens, and the optical center of the lens is offset relative to the optical axis of the second lens group and/or the optical axis of the lens is deflected from the optical axis of the second lens group;
the focal length of the lens is larger than a preset focal length threshold, and the difference degree between the focal length of the second lens group and the focal length of the optical system is smaller than the preset difference threshold.
In one possible embodiment, the preset focal length threshold is 100 and the difference threshold is 10% of the focal length of the optical system.
In one possible embodiment, the first lens group includes a first lens;
the first lens is arranged at the position closest to the object side in the first lens group;
the first lens is a free-form surface lens, the optical axis of the first lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [0 degrees, 25 degrees ].
In one possible embodiment, the first lens group further comprises a second lens;
the second lens is arranged on the image side of the first lens;
the second lens is a spherical lens, the optical axis of the second lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [ -10 degrees, 0 degrees).
In a possible embodiment, the optical system is characterized in that the first lens group further comprises a third lens;
the third lens is arranged on the image side of the second lens;
the third lens is a spherical lens, the optical axis of the third lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [ -15 degrees, 0 degrees).
In one possible embodiment, the first lens group further comprises a fourth lens;
the fourth lens is arranged on the image side of the third lens;
the fourth lens is a spherical lens, the optical axis of the fourth lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [ -25 degrees, 0 degrees).
In one possible embodiment, the second lens group includes a fifth lens;
the fifth lens is arranged at the position closest to the object side in the second lens group;
the focal length of the fifth lens is negative, and the image plane and the object plane of the fifth lens are concave spherical surfaces.
In one possible embodiment, the second lens group further includes a sixth lens;
the sixth lens is arranged on the image side of the fifth lens;
the focal length of the sixth lens is positive, and the image plane and the object plane of the sixth lens are convex spherical surfaces;
the focal length of the sixth lens has a value range (|F) 5 |，2*|F 5 I), wherein F 5 Is the focal length of the fifth lens.
In one possible embodiment, the second lens group further includes: a seventh lens and an eighth lens;
the seventh lens is arranged on the image side of the sixth lens, and the eighth lens is arranged on the image side of the seventh lens;
the focal length of the seventh lens is positive, and the object plane of the seventh lens is a convex spherical surface;
the focal length of the eighth lens is positive, the object plane of the eighth lens is a convex spherical surface, and the radius of curvature of the object plane of the eighth lens is smaller than the radius of curvature of the image plane of the eighth lens.
In one possible embodiment, the second lens group further includes: a ninth lens and a tenth lens;
the ninth lens is arranged on the image side of the eighth lens, and the tenth lens is arranged on the image side of the ninth lens;
the focal length of the ninth lens is negative, and the ninth lens is a meniscus lens or a plano-concave lens;
the focal length of the tenth lens is positive, and the object plane of the tenth lens is a convex spherical surface, and the object plane of the tenth lens is adhered to the image plane of the ninth lens.
In one possible embodiment, the second lens group further includes: an eleventh lens and a twelfth lens;
the eleventh lens is arranged on the image side of the tenth lens, and the twelfth lens is arranged on the image side of the eleventh lens;
the focal length of the eleventh lens is positive, and the object plane and the image plane of the eleventh lens are convex spherical surfaces;
the focal length of the twelfth lens is negative, the object plane and the image plane of the twelfth lens are concave spherical surfaces, and the lens of the twelfth lens is adhered to the image plane of the eleventh lens;
a magnitude relation between a refractive index of the eleventh lens and an abbe number of the twelfth lens is opposite to a magnitude relation between an abbe number of the eleventh lens and an abbe number of the twelfth lens.
In one possible embodiment, the second lens group further includes: a thirteenth lens;
the thirteenth lens is arranged on the image side of the twelfth lens, the focal length of the thirteenth lens is positive, and the object plane and the image plane of the thirteenth lens are convex spherical surfaces;
the temperature coefficient of the material of the thirteenth lens is larger than a preset coefficient threshold.
In one possible embodiment, the object plane of the thirteenth lens is adhered to the image plane of the twelfth lens.
In one possible embodiment, the second lens group further includes a fourteenth lens;
the fourteenth lens is arranged on the image side of the thirteenth lens;
the focal length of the fourteenth lens is positive, and the object plane of the fourteenth lens is a convex spherical surface;
the range of the curvature radius of the object plane of the fourteenth lens is (0.5×l10r2,1.5×l10r2), where L10R2 is the curvature radius of the image plane of the fourteenth lens;
the distance between the fourteenth lens and the image plane is larger than a preset distance threshold.
In one possible embodiment, the second lens group further includes a fifteenth lens;
the fifteenth lens is arranged on the image side of the fourteenth lens;
the fifteenth lens is a planar lens and is provided with a coating film for filtering non-visible light.
In one possible embodiment, each lens in the second lens group is made of glass.
The embodiment of the application has the beneficial effects that:
according to the long-focus large-aperture extended-depth-of-field optical system provided by the embodiment of the application, the optical path difference caused by the non-parallel object plane and image plane can be corrected through the first lens group arranged in front of the image plane and the lens with smaller eccentric and/or deflection focal power in the first lens group, so that the problem of long-focus large-aperture extended-depth-of-field optical system is solved when the lens is installed.
Of course, it is not necessary for any one product or method of practicing the application to achieve all of the advantages set forth above at the same time.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the application, and other embodiments may be obtained according to these drawings to those skilled in the art.
Fig. 1 is a two-dimensional view of an optical system according to an embodiment of the present application.
Fig. 2 is a schematic structural diagram of an optical system according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by the person skilled in the art based on the present application are included in the scope of protection of the present application.
In order to more clearly describe the optical system with the long-focus large aperture and wide depth of field provided by the embodiment of the present application, an exemplary description will be given below of one possible application scenario of the optical system with the long-focus large aperture and wide depth of field provided by the embodiment of the present application, and the following examples are only one possible application scenario of the optical system with the long-focus large aperture and wide depth of field provided by the embodiment of the present application, and in other possible embodiments, the optical system with the long-focus large aperture and wide depth of field provided by the embodiment of the present application may also be applied to other possible application scenarios, and the following examples do not limit any limitation.
Because the longer the focal length is, the higher the magnification is, so that the consideration of shooting detail images is that some monitoring cameras adopt a long-focus lens, but because the aperture of the long-focus lens is enlarged after the aperture is enlarged, the larger the aberration is, the more difficult the imaging quality of the peripheral view field is ensured, the aperture of the long-focus lens is often smaller, such as FNO1.8 and FNO1.6, so that the overall picture brightness of the image shot by the lens is lower and the image effect is poorer in a low-illumination environment.
In addition, the depth of field of the long-focus lens is often smaller, and when the monitoring equipment is installed, a depression angle is often formed between the lens and the monitored environment, so that distances between all spatial points in the monitored environment and the lens are inconsistent, namely, part of spatial points in the monitored environment are located in close range of a shot monitoring image, part of spatial points are located in distant range of the shot monitoring image, and for the lens with a small depth of field, the conditions of clear focusing position image, and blurred close range image and distant range image in the image can occur.
Therefore, a lens with a long focal length and a large aperture expansion depth of field is needed to solve the above technical problems. Based on this, the embodiment of the application provides an optical system with long focal length and large aperture expansion depth, as shown in fig. 1, a first lens group and a second lens group are sequentially arranged from an object direction image side in the optical system;
the optical axes of the lenses in the second lens group are overlapped;
the first lens group comprises at least one lens, and the optical center of the lens is offset relative to the optical axis of the second lens group and/or the optical axis of the lens is deflected from the optical axis of the second lens group;
the focal length of the lens is larger than a preset focal length threshold, and the difference degree between the focal length of the second lens group and the focal length of the optical system is smaller than the preset difference threshold.
By adopting the embodiment, the optical path difference caused by the non-parallel object plane and image plane can be corrected through the first lens group arranged in front of the image plane and the lens with smaller eccentric and/or deflected focal power in the first lens group, so that the problem of virtual focus of long-focus and large-aperture extended-field depth during lens installation is solved, and the long-focus and large-aperture extended-field optical system is realized.
Wherein, the object direction refers to a direction approaching the object, and the image direction refers to a direction approaching the image plane. The second lens group and the first lens group are both positioned on the object direction of the image plane. One or more lenses are included in the second lens group and the first lens group, and a spherical lens may be included in the first lens group in addition to the aspherical lens. The aspherical lens may be offset from the optical axis of the second lens group and may not be offset from the optical axis of the second lens group, or may be offset from the optical axis of the second lens group and may not be offset from the optical axis of the second lens group.
The amount of offset and the amount of deflection of the offset may be different depending on the application scene, and the amounts of deflection of different lenses in the first lens group may be different.
The preset focus threshold may be set according to user requirements or practical experience, for example, in one possible embodiment, the preset focus threshold is 100. Similarly, the magnitude of the difference threshold may be set according to the user requirement or actual experience, and the difference threshold may be a fixed value or may be determined according to the focal length of the optical system, and the difference threshold is exemplified by 10% of the focal length of the optical system, and the focal length of the optical system is referred to as F for convenience of description, and the focal length of the second lens group is referred to as F Rear part (S) 0.9<F Rear part (S) /F<1.1。
The constitution of the first lens group will be described below:
in one possible embodiment, the first lens group includes a first lens;
the first lens is arranged at the position closest to the object side in the first lens group, namely other lenses in the first lens group are positioned at the image side of the first lens;
the first lens is a free-form surface lens, the optical axis of the first lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [0 degrees, 25 degrees ].
In this embodiment, since the optical axis of the first lens element has a certain inclination angle with respect to the optical axis of the second lens element, the inclination angle of the object plane with respect to the image plane can be compensated. Therefore, the optical path difference is caused by the fact that the correction object plane is not parallel to the image plane, so that the optical path difference of light emitted by each point on the object plane to reach the image plane is similar or even the same.
In one possible embodiment, the first lens group further comprises a second lens;
the second lens is arranged on the image side of the first lens;
the second lens is a spherical lens, the optical axis of the second lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [ -10 degrees, 0 degrees).
In this embodiment, the second lens is additionally disposed on the basis of the first lens, and since a certain inclination angle exists between the optical axis of the second lens and the optical axis of the second lens group, the inclination angle of the object plane relative to the image plane can be further compensated, so that the optical path difference caused by the non-parallel object plane and the image plane can be better corrected.
Also, in another possible embodiment, the second lens is an aspherical lens or a free-form surface lens to correct aberration of light while correcting an optical path difference.
In one possible embodiment, the first lens group further includes a third lens;
the third lens is arranged on the image side of the second lens;
the third lens is a spherical lens, the optical axis of the third lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [ -15 degrees, 0 degrees).
In this embodiment, the third lens is additionally disposed on the basis of the first lens and the second lens, and since a certain inclination angle exists between the optical axis of the third lens and the optical axis of the second lens group, the inclination angle of the object plane and the image plane can be further compensated, so that the optical path difference caused by the non-parallel object plane and the image plane can be better corrected.
Also, in another possible embodiment, the third lens is an aspherical lens or a free-form surface lens to correct aberration of light while correcting an optical path difference.
In one possible embodiment, the first lens group further comprises a fourth lens;
the fourth lens is arranged on the image side of the third lens;
the fourth lens is a spherical lens, the optical axis of the fourth lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [ -25 degrees, 0 degrees).
In this embodiment, the fourth lens is additionally disposed on the basis of the first lens, the second lens and the third lens, and since a certain inclination angle exists between the optical axis of the fourth lens and the optical axis of the second lens group, the inclination angle of the object plane relative to the image plane can be further compensated, so that the optical path difference caused by non-parallel object plane and image plane can be better corrected.
Also, in another possible embodiment, the fourth lens is an aspherical lens or a free-form surface lens to correct aberration of light while correcting an optical path difference.
The constitution of the second lens group will be described below:
in one possible embodiment, the second lens group includes a fifth lens;
the fifth lens is arranged at the position closest to the object side in the second lens group, namely other lenses in the second lens group are positioned at the image side of the fifth lens;
the focal length of the fifth lens is negative, and the image plane and the object plane of the fifth lens are concave spherical surfaces.
In this embodiment, since the image surface and the object surface of the fifth lens are concave spherical surfaces, light rays can be better converged, and meanwhile, since the fifth lens is located at a position closest to the object side in the second lens group, the converging light rays of the fifth lens can make the cross section of light rays incident to other lenses in the second lens group smaller, so that the aperture of the front section of the lens is reduced.
In one possible embodiment, the second lens group further includes a sixth lens;
the sixth lens is arranged on the image side of the fifth lens;
the focal length of the sixth lens is positive, and the image plane and the object plane of the sixth lens are convex spherical surfaces;
the focal length of the sixth lens has a value range (|F) 5 |，2*|F 5 I), wherein F 5 Is the focal length of the fifth lens.
In this embodiment, since the image surface and the object surface of the sixth lens are both convex spherical surfaces, the light converging through the fifth lens can be better dispersed, so as to facilitate the realization of a large aperture. And, the fifth lens and the sixth lens are used in combination, so that the spherical aberration of the lens can be effectively reduced, and the quality of a shot image is improved.
The fifth lens and the sixth lens may be two lenses independent of each other, or may be two lenses bonded together, for example, the fifth lens and the sixth lens are bonded by uv glue.
In one possible embodiment, the second lens group further includes: a seventh lens and an eighth lens;
the seventh lens is arranged on the image side of the sixth lens, and the eighth lens is arranged on the image side of the seventh lens;
the focal length of the seventh lens is positive, and the object plane of the seventh lens is a convex spherical surface;
the focal length of the eighth lens is positive, the object plane of the eighth lens is a convex spherical surface, and the radius of curvature of the object plane of the eighth lens is smaller than the radius of curvature of the image plane of the eighth lens.
In this embodiment, the seventh lens makes the light scattered by the sixth lens smoothly transition to the fourth lens, and the eighth lens converges the incident light again, so that on one hand, the aperture of the rear section of the lens can be reduced conveniently, and on the other hand, the total length of the lens can be shortened.
In order for the eighth lens to be able to better focus the light rays, in one possible embodiment, the radius of curvature L8R1 of the object plane of the eighth lens and the radius of curvature L8R2 of the image plane of the eighth lens should satisfy: 0 < L8R1/L8R2 < 1.
In one possible embodiment, the second lens group further includes: a ninth lens and a tenth lens;
the ninth lens is arranged on the image side of the eighth lens, and the tenth lens is arranged on the image side of the ninth lens;
the focal length of the ninth lens is negative, and the ninth lens is a meniscus lens or a plano-concave lens;
the focal length of the tenth lens is positive, and the object plane of the tenth lens is a convex spherical surface, and the object plane of the tenth lens is adhered to the image plane of the ninth lens.
In this embodiment, through the mutual cooperation of the ninth lens and the tenth lens, the chromatic aberration of the lens can be effectively reduced, the imaging quality of the peripheral view field is improved, and meanwhile, because the ninth lens and the tenth lens are bonded, the tolerance sensitivity of the lens can be reduced, and the assembly difficulty of the lens is reduced.
And, a diaphragm may be further included between the eighth lens and the ninth lens to restrict light incident to the ninth lens.
In one possible embodiment, the second lens group further includes: an eleventh lens and a twelfth lens;
the eleventh lens is arranged on the image side of the tenth lens, and the twelfth lens is arranged on the image side of the eleventh lens;
the focal length of the eleventh lens is positive, and the object plane and the image plane of the eleventh lens are convex spherical surfaces;
the focal length of the twelfth lens is negative, the object plane and the image plane of the twelfth lens are concave spherical surfaces, and the object plane of the twelfth lens is adhered to the image plane of the eleventh lens;
a magnitude relation between a refractive index of the eleventh lens and an abbe number of the twelfth lens is opposite to a magnitude relation between an abbe number of the eleventh lens and an abbe number of the twelfth lens.
In this embodiment, by the interaction between the eleventh lens and the twelfth lens, the chromatic aberration of the light incident on the eleventh lens and the twelfth lens can be reduced, and the quality of the captured image can be improved. The eleventh lens and the twelfth lens can be two independent lenses or two lenses bonded together, and tolerance sensitivity of the lens can be reduced and assembly difficulty of the lens can be reduced by bonding the eleventh lens and the twelfth lens.
The magnitude relation between the refractive index of the eleventh lens and the refractive index of the twelfth lens, which is opposite to the magnitude relation before the abbe number of the eleventh lens and the abbe number of the twelfth lens, means: the abbe number of the eleventh lens is smaller than the abbe number of the twelfth lens if the refractive index of the eleventh lens is larger than the refractive index of the twelfth lens, and the abbe number of the eleventh lens is larger than the abbe number of the twelfth lens if the refractive index of the eleventh lens is smaller than the refractive index of the twelfth lens.
For convenience of description, the refractive index of the eleventh lens is denoted as nd11, the abbe number of the eleventh lens is denoted as vd11, the refractive index of the twelfth lens is denoted as nd12, and the abbe number of the twelfth lens is denoted as vd12, it should be satisfied that: (nd 11-nd 12)/(vd 11-vd 12) < 0.
In some application scenarios, the lens may need to work at a high temperature or a low temperature, so the lens is required to have a higher high-low temperature performance, in these application scenarios, the temperature coefficient of the material of the eleventh lens is greater than a preset coefficient threshold, and in the present application, the temperature coefficient refers to a rate at which the optical performance of the lens changes with temperature change, and since the optical performance of the lens decreases with temperature increase, that is, the rate is a negative value, the rate at which the optical performance of the material with a higher temperature coefficient changes with temperature change is slower.
In one possible embodiment, the second lens group further includes: a thirteenth lens;
the thirteenth lens is arranged on the image side of the twelfth lens, the focal length of the thirteenth lens is positive, and the object plane and the image plane of the thirteenth lens are convex spherical surfaces;
the temperature coefficient of the material of the thirteenth lens is larger than a preset coefficient threshold.
In this embodiment, the thirteenth lens is made of a material with a larger temperature coefficient, so that the high-low temperature performance of the lens is further improved, and the lens can work in a high-temperature and low-temperature scene better.
Depending on the application scenario, the preset coefficient threshold may be different, and in one possible embodiment, the coefficient threshold is-1×10 -6 I.e. the temperature coefficient D0 (13) of the thirteenth lens should satisfy-1 x 10 -6 ＜D0(13)＜0。
In one possible embodiment, the thirteenth lens may be independent of the twelfth lens, and in another possible embodiment, an object plane of the thirteenth lens is adhered to an image plane of the twelfth lens.
In the embodiment, since the thirteenth lens is adhered to the twelfth lens, the assembling tolerance sensitivity of the thirteenth lens can be reduced, thereby further reducing the assembling difficulty of the lens.
In one possible embodiment, the second lens group further includes a fourteenth lens;
the fourteenth lens is arranged on the image side of the thirteenth lens;
the focal length of the fourteenth lens is positive, and the object plane of the fourteenth lens is a convex spherical surface;
the range of the curvature radius of the object plane of the fourteenth lens is (0.5×l10r2,1.5×l10r2), where L10R2 is the curvature radius of the image plane of the fourteenth lens;
in this embodiment, through the mirror surface of rational design fourteenth lens for fourteenth lens can possess stronger ability of converging light, consequently can make the light that passes through fourteenth lens focus more fast and image on great photosurface, effectively shortened the total length of camera lens, can realize big target surface simultaneously.
In one possible embodiment, the second lens group further includes a fifteenth lens;
the fifteenth lens is arranged on the image side of the fourteenth lens;
the fifteenth lens is a planar lens and is provided with a coating film for filtering non-visible light.
The plane lens means that the object plane and the image plane of the fifteenth lens are planes perpendicular to the optical axis of the second lens group. The material and thickness of the coating film of the fifteenth lens may be different according to the application scenario, but the coating film should have the effect of filtering non-visible light, and the coating film should allow visible light to pass through.
In this embodiment, since the fifteenth lens is provided with a film capable of filtering non-visible light, the non-visible light, such as near infrared light, far infrared light, and the like, in the light beam cannot reach the photosensitive surface of the sensor through the fifteenth lens, so that aberration caused by the non-visible light can be effectively avoided, and the quality of the captured image is further improved.
In one possible embodiment, the material of each lens in the second lens group is glass, and in this embodiment, the second lens group is constructed by using a glass lens, so that on one hand, the cost of the first lens group can be effectively reduced, and on the other hand, the rate of change of the optical performance of the glass along with the change of temperature is lower because the temperature coefficient of the glass is relatively larger, so that the stability of the lens can be improved by using the glass material.
In the following, an exemplary description will be given of an example in which the first lens group includes the aforementioned first lens to fourth lens, the second lens group includes the aforementioned fifth lens and fifteenth lens, and a stop is provided between the eighth lens and ninth lens.
In one possible embodiment, the overall focal length f=49.35 mm of the optical system, the F-number fno=1.0, the field angle fov=15°.
Table 1 shows specific parameters of one embodiment of the optical system of the present application:
TABLE 1
Wherein the plane number of one mirror is the order of the mirror in the order from the object side to the image side, for example, the plane number of the object plane of the first lens is 1, the plane number of the image plane of the first lens is 2, the plane number of the object plane of the second lens is 3, the plane number of the image plane of the second lens is 4, and so on.
The mirror shape of the first lens is defined by the following formula:
wherein z is the sagittal height parallel to the optical axis, C is the curvature, k is the conic coefficient, C j Is x m y n Is a coefficient of (a). The correlation coefficients are shown in table 2 below.
TABLE 2
| Face number | K | C2 | C3 | C4 | C5 |
| 1 | 0 | -7.2221e-7 | 0.3124 | 6.5256e-5 | 2.8429e-10 |
From the data in tables 1 and 2, it can be calculated that the lens in this embodiment satisfies the following conditions:
|F6/F5|＝1.49,F7＝70mm,L7R1/L7R2＝0.16,(nd11-nd12)/(vd11-vd12)＝-0.006,D0(13)＝-2E-5,L14R1/L14R2＝1.04,|F1|＝134,|F2|＝850,|F3|＝2238,|F4|＝9037,α 1 ＝18.2446°，α 2 ＝-5.5225°，α 3 ＝-9.7402°,α 4 ＝-19.3826°,F rear part (S) /F＝1.0。
Wherein F6 is a focal length of the sixth lens, F5 is a focal length of the fifth lens, F7 is a focal length of the seventh lens, L7R1 is a radius of curvature of an object plane of the seventh lens, L7R2 is a radius of curvature of an image plane of the seventh lens, F1 is a focal length of the first lens, F2 is a focal length of the second lens, F3 is a focal length of the third lens, F4 is a focal length of the fourth lens, α1 is a deflection angle of an optical axis of the first lens with respect to an optical axis of the second lens group, α1 is a deflection angle of an optical axis of the second lens with respect to an optical axis of the second lens group, α3 is a deflection angle of an optical axis of the first lens with respect to an optical axis of the second lens group.
As shown in table 1, as a specific set of example parameters, optical lenses employing these parameters can achieve better optical performance. In this example, the structure of the optical system is shown in fig. 2.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.
Claims (8)
1. An optical system with a long focus and a large aperture expansion depth of field is characterized in that a first lens group and a second lens group are sequentially arranged from an object direction image side in the optical system;
the optical axes of the lenses in the second lens group are overlapped;
the first lens group comprises at least one lens, and the optical center of the lens is offset relative to the optical axis of the second lens group and/or the optical axis of the lens is deflected from the optical axis of the second lens group;
the focal length of the lens is larger than a preset focal length threshold, and the degree of difference between the focal length of the second lens group and the focal length of the optical system is smaller than a preset difference threshold;
the second lens group comprises a fifth lens;
the fifth lens is arranged at the position closest to the object side in the second lens group;
the focal length of the fifth lens is negative, and the image plane and the object plane of the fifth lens are concave spherical surfaces;
the second lens group further comprises a sixth lens;
the sixth lens is arranged on the image side of the fifth lens;
the focal length of the sixth lens is positive, and the image plane and the object plane of the sixth lens are convex spherical surfaces;
the focal length of the sixth lens has a value range (|F) 5 |，2*|F 5 I), wherein F 5 Is the focal length of the fifth lens.
2. The optical system of claim 1, wherein the preset focal length threshold is 100 and the difference threshold is 10% of the focal length of the optical system.
3. The optical system of claim 1, wherein the first lens group comprises a first lens;
the first lens is arranged at the position closest to the object side in the first lens group;
the first lens is a free-form surface lens, the optical axis of the first lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [0 degrees, 25 degrees ].
4. The optical system of claim 3, wherein the first lens group further comprises a second lens;
the second lens is arranged on the image side of the first lens;
the second lens is a spherical lens, the optical axis of the second lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [ -10 degrees, 0 degrees).
5. The optical system of claim 4, wherein the first lens group further comprises a third lens;
the third lens is arranged on the image side of the second lens;
the third lens is a spherical lens, the optical axis of the third lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [ -15 degrees, 0 degrees).
6. The optical system of claim 5, wherein the first lens group further comprises a fourth lens;
the fourth lens is arranged on the image side of the third lens;
the fourth lens is a spherical lens, the optical axis of the fourth lens is offset relative to the optical axis of the second lens group, and the value range of the offset is [ -25 degrees, 0 degrees).
7. The optical system of claim 1, wherein the second lens group further comprises: a seventh lens and an eighth lens;
the seventh lens is arranged on the image side of the sixth lens, and the eighth lens is arranged on the image side of the seventh lens;
the focal length of the seventh lens is positive, and the object plane of the seventh lens is a convex spherical surface;
the focal length of the eighth lens is positive, the object plane of the eighth lens is a convex spherical surface, and the radius of curvature of the object plane of the eighth lens is smaller than the radius of curvature of the image plane of the eighth lens.
8. The optical system of claim 7, wherein the second lens group further comprises: a ninth lens and a tenth lens;
the ninth lens is arranged on the image side of the eighth lens, and the tenth lens is arranged on the image side of the ninth lens;
the focal length of the ninth lens is negative, and the ninth lens is a meniscus lens or a plano-concave lens;
the focal length of the tenth lens is positive, and the object plane of the tenth lens is a convex spherical surface, and the object plane of the tenth lens is adhered to the image plane of the ninth lens.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06130203A (en) * | 1992-10-15 | 1994-05-13 | Asahi Optical Co Ltd | Eccentric lens and vibration compensation lens system |
| TW200623094A (en) * | 2004-08-31 | 2006-07-01 | Konica Minolta Opto Inc | Lens unit for optical pick-up apparatus, optical element for optical pick-up apparatus, lens frame for lens unit, assembly method of the lens unit, and optical pick-up apparatus |
| JP2009181009A (en) * | 2008-01-31 | 2009-08-13 | Tamron Co Ltd | Real image type variable power finder |
| CN110476099A (en) * | 2017-04-07 | 2019-11-19 | 奥林巴斯株式会社 | Rigid scope |
| CN215813529U (en) * | 2021-07-02 | 2022-02-11 | 舜宇光学(中山)有限公司 | Long focus lens |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6664068B2 (en) * | 2017-10-27 | 2020-03-13 | パナソニックＩｐマネジメント株式会社 | Zoom lens system and imaging device |
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- 2022-03-25 CN CN202210305624.9A patent/CN114647070B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06130203A (en) * | 1992-10-15 | 1994-05-13 | Asahi Optical Co Ltd | Eccentric lens and vibration compensation lens system |
| TW200623094A (en) * | 2004-08-31 | 2006-07-01 | Konica Minolta Opto Inc | Lens unit for optical pick-up apparatus, optical element for optical pick-up apparatus, lens frame for lens unit, assembly method of the lens unit, and optical pick-up apparatus |
| JP2009181009A (en) * | 2008-01-31 | 2009-08-13 | Tamron Co Ltd | Real image type variable power finder |
| CN110476099A (en) * | 2017-04-07 | 2019-11-19 | 奥林巴斯株式会社 | Rigid scope |
| CN215813529U (en) * | 2021-07-02 | 2022-02-11 | 舜宇光学(中山)有限公司 | Long focus lens |
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