CN113253430B - Wide-angle lens and imaging apparatus - Google Patents
Wide-angle lens and imaging apparatus Download PDFInfo
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- CN113253430B CN113253430B CN202110701278.1A CN202110701278A CN113253430B CN 113253430 B CN113253430 B CN 113253430B CN 202110701278 A CN202110701278 A CN 202110701278A CN 113253430 B CN113253430 B CN 113253430B
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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
- G02B13/06—Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
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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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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
- G02B7/028—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
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Abstract
The invention discloses a wide-angle lens and imaging equipment, the wide-angle lens comprises the following components in sequence from an object side to an imaging surface along an optical axis: the first lens with negative focal power has a convex object-side surface and a concave image-side surface; a second lens with negative focal power, wherein the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; a diaphragm; a third lens with positive focal power, wherein the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; a fourth lens with positive focal power, wherein 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; a fifth lens element having a negative refractive power, the object-side surface of which is concave and the image-side surface of which is concave; a sixth lens with positive focal power, wherein the object-side surface of the sixth lens is a convex surface, and the image-side surface of the sixth lens is a convex surface; a seventh lens element with negative optical power having a convex object-side surface and an inflection point at a paraxial region, and a concave image-side surface and an inflection point at a paraxial region. The wide-angle lens at least has the advantages of super large aperture, large field angle, high pixel, miniaturization, good thermal stability and low cost.
Description
Technical Field
The invention relates to the technical field of imaging lenses, in particular to a wide-angle lens and imaging equipment.
Background
With the gradual expansion of the application range and the scene of the security monitoring video technology and the increasingly strengthened requirements of security monitoring in the aspects of high definition, networking, intellectualization and the like, the technical level requirements of security monitoring lens products in the aspects of obtaining a large visual field, outputting high-definition images, performing day-night confocal color imaging, overcoming the influence of severe environment on imaging quality and the like are also increasingly improved.
Most of monitoring lenses popular in the market at present have smaller apertures and most of F # is more than 2.0, so that the lenses have poor imaging effect and low resolution ratio in strong light and low-illumination environments, and cannot meet the requirement of day and night high-definition imaging in indoor and outdoor complex ambient light; some monitoring lenses have small field angles, are difficult to acquire imaging pictures in a large field of view, and cannot meet actual requirements; in addition, many monitoring lenses have more lenses, even lenses made of all-glass materials, so that the lenses have higher cost and larger volume, and are not favorable for popularization and application in the market.
Disclosure of Invention
Therefore, the present invention is directed to a wide-angle lens and an imaging device, which have at least the advantages of an ultra-large aperture, a large field angle, high pixels, miniaturization, good thermal stability, and relatively low cost.
The embodiment of the invention implements the above object by the following technical scheme.
In a first aspect, the present invention provides a wide-angle lens, comprising, in order from an object side to an image plane along an optical axis: the lens comprises a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an optical filter and protective glass. The first lens has negative focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens has negative focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the third lens has positive focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the fourth lens has positive focal power, the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the fifth lens has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface; the sixth lens has positive focal power, the object-side surface of the sixth lens is a convex surface, and the image-side surface of the sixth lens is a convex surface; the seventh lens element has a negative optical power, an object side surface of the seventh lens element being convex at a paraxial region and having an inflection point, and an image side surface of the seventh lens element being concave at the paraxial region and having an inflection point. The wide-angle lens meets the following conditional expression: 0.9< F # <1, F # representing the F-number of the wide-angle lens.
In a second aspect, the present invention provides an imaging apparatus including an imaging element for converting an optical image formed by the wide-angle lens into an electric signal, and the wide-angle lens provided in the first aspect.
Compared with the prior art, the wide-angle lens and the imaging equipment provided by the invention effectively control the hot focal point offset by reasonably matching the shape and focal power combination of the glass-plastic mixed lens, so that the lens still has good imaging performance in high and low temperature environments (minus 30-70 ℃); the position of the diaphragm and the surface shape of each lens are reasonably arranged, so that the lens has the characteristics of large wide angle and super-large aperture, and the imaging requirement of a light and shade environment is met; meanwhile, the system has the advantages of high pixel, miniaturization and relatively low cost, and can meet the use requirements of security monitoring equipment.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a schematic structural diagram of a wide-angle lens in a first embodiment of the present invention;
FIG. 2 is a vertical axis chromatic aberration diagram of the wide-angle lens according to the first embodiment of the present invention;
fig. 3 is an MTF chart of the wide-angle lens in the first embodiment of the present invention;
FIG. 4 is a defocus plot of the wide-angle lens at 20 deg.C;
FIG. 5 is a defocus graph of the wide-angle lens at-30 deg.C;
FIG. 6 is a defocus graph of the wide-angle lens at a high temperature of 70 ℃ in the first embodiment of the present invention;
fig. 7 is a schematic structural diagram of a wide-angle lens in a second embodiment of the present invention;
FIG. 8 is a vertical axis chromatic aberration diagram of a wide-angle lens according to a second embodiment of the present invention;
fig. 9 is an MTF chart of a wide-angle lens in a second embodiment of the present invention;
fig. 10 is a schematic structural diagram of a wide-angle lens in a third embodiment of the present invention;
FIG. 11 is a vertical axis chromatic aberration diagram of a wide-angle lens according to a third embodiment of the present invention;
fig. 12 is an MTF chart of a wide-angle lens in a third embodiment of the present invention;
FIG. 13 is a schematic diagram showing the vertical distance between the inflection point and the optical axis of the seventh lens element;
fig. 14 is a schematic structural view of an image forming apparatus according to a fourth embodiment of the present invention.
Detailed Description
In order to make the objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. Several embodiments of the invention are presented in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Like reference numerals refer to like elements throughout the specification.
The invention provides a wide-angle lens, which sequentially comprises the following components from an object side to an imaging surface along an optical axis: the lens comprises a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an optical filter and protective glass.
The first lens has negative focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;
the second lens has negative focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface;
the third lens has positive focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface;
the fourth lens has positive focal power, and both the object side surface and the image side surface of the fourth lens are convex surfaces;
the fifth lens has negative focal power, and the object side surface and the image side surface of the fifth lens are both concave surfaces;
the sixth lens has positive focal power, and both the object-side surface and the image-side surface of the sixth lens are convex surfaces;
the seventh lens element has a negative optical power, an object-side surface of the seventh lens element being convex and having an inflection point at a paraxial region, and an image-side surface of the seventh lens element being concave and having an inflection point at a paraxial region.
In order to improve the thermal stability of the lens, the glass-plastic mixed lens structure is adopted, so that the miniaturization and the low cost are realized, and the good imaging effect of the lens can be ensured. Specifically, the third lens can be a glass spherical lens, which can correct the temperature drift of the system well and improve the thermal stability of the lens. The first lens, the second lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens can be plastic aspheric lenses, and the aspheric lenses are adopted, so that the number of lenses can be effectively reduced, aberration can be corrected, and better optical performance can be provided.
Further, the wide-angle lens satisfies the following conditional expression:
0.9≤F#≤1.0；（1）
wherein F # denotes an F-number of the wide-angle lens. The F # is the ratio of the effective focal length of the lens to the clear aperture of the lens, and a smaller F # indicates a larger aperture of the wide-angle lens. When the condition formula (1) is met, the wide-angle lens has the characteristic of an oversized aperture, the luminous flux entering the lens is increased to a certain extent, and particularly, the influence of noise caused by insufficient light on an imaging picture can be reduced under a dark environment at night, so that the imaging quality is improved.
In some embodiments, the wide-angle lens satisfies the following conditional expression:
1.1<f/IH<1.2；（2）
where f represents the effective focal length of the wide-angle lens, and IH represents the actual half-image height of the wide-angle lens. When the conditional expression (2) is satisfied, the optical system can be made compact and miniaturized while having high pixel performance.
In some embodiments, the wide-angle lens satisfies the following conditional expression:
9.0mm<f*tanθ<9.5mm；（3）
where f denotes an effective focal length of the wide-angle lens, and θ denotes a half field angle of the wide-angle lens. When the conditional expression (3) is satisfied, the optical system has a larger field angle, and can satisfy the shooting requirement of a large wide angle, and meanwhile, the optical system also has a larger imaging surface, and can realize higher pixel performance.
In some embodiments, the wide-angle lens satisfies the following conditional expression:
1.95<(SAG11+SAG12)/CT1<2.1；（4）
where SAG11 represents the saggital height of the object-side surface of the first lens, SAG12 represents the saggital height of the image-side surface of the first lens, and CT1 represents the center thickness of the first lens. The surface shape of the first lens can be reasonably limited by satisfying the conditional expression (4), and the processing difficulty of the lens is reduced on the premise of ensuring the bending force of the lens on light; if the value of (SAG11+ SAG12)/CT1 exceeds the lower limit, the light ray bending capability of the first lens is insufficient, and the total length of the lens is long; if the value of (SAG11+ SAG12)/CT1 exceeds the upper limit, the object-side surface of the first lens is convex and conspicuous, resulting in difficulty in lens forming.
In some embodiments, the wide-angle lens satisfies the following conditional expression:
0.4<CT1/CT3<1.0；（5）
where CT1 denotes the center thickness of the first lens and CT3 denotes the center thickness of the third lens. Satisfy conditional expression (5), can rationally control the thickness ratio of first lens and third lens, under the prerequisite of guaranteeing that the lens is normally processed, the reduction system leads to the drift of imaging surface because of being heated. If the value of CT1/CT3 exceeds the lower limit, the thermal expansion of the first lens element and the third lens element cannot effectively compensate the thermal expansion of the rear lens element under high temperature condition of the lens, which results in large back focus of the lens and reduced imaging quality; on the contrary, if the value of CT1/CT3 exceeds the upper limit, the back focus of the lens is reduced, and the imaging quality is reduced.
In some embodiments, the wide-angle lens satisfies the following conditional expression:
0.5<R32/f3<3.0；（6）
0.1<R31/R32<0.8；（7）
0.001mm/℃<f3*(dn/dt)3<0.003mm/℃；（8）
wherein R31 represents the curvature radius of the object side surface of the third lens, R32 represents the curvature radius of the image side surface of the third lens, f3 represents the effective focal length of the third lens, and (dn/dt)3 represents the temperature coefficient of the refractive index of the material of the third lens at 20-70 ℃. The refractive power of the third lens element can be reasonably distributed to avoid the imbalance of aberration caused by excessive refractive power of the front lens element group when the conditional expressions (6) to (8) are satisfied; meanwhile, the thermal drift generated by the front lens group and the rear lens group in a high-low temperature environment (minus 30-70 ℃) can be integrated, so that the lens still has good imaging performance in the high-low temperature environment, the thermal stability of the lens is improved, and the application range and the use scene of the lens are widened.
In some embodiments, the wide-angle lens satisfies the following conditional expression:
1.35<(YR71+ YR72)/IH<1.50；（9）
wherein, YR71Denotes the perpendicular distance, Y, of the inverse curve on the object-side surface of the seventh lens element from the optical axisR72The vertical distance between an inflection point on the image side surface of the seventh lens and an optical axis is represented, IH represents the actual half image height of the wide-angle lens, and Y is specificR71And YR72Can be seen in fig. 13. The object side face and the image side face of the seventh lens are provided with the inflection points, the conditional expression (9) is satisfied, the positions of the inflection points on the object side face and the image side face of the seventh lens can be reasonably set, coma aberration correction of an off-axis field of view is facilitated to be enhanced, meanwhile, the convergence field curvature is good, and the imaging quality is improved.
In some embodiments, the wide-angle lens satisfies the following conditional expression:
0.25<(ET5-CT5)/(ET5+CT5)<0.45；（10）
where CT5 denotes the center thickness of the fifth lens and ET5 denotes the edge thickness of the fifth lens. When the conditional expression (10) is satisfied, the shape of the fifth lens can be reasonably limited, and the processing difficulty of the lens is reduced on the premise of ensuring the light divergence capability of the biconcave lens; if the value of (ET5-CT5)/(ET5+ CT5) exceeds the lower limit, the fifth lens will have insufficient light ray diverging ability and will result in a long total lens length; if the value of (ET5-CT5)/(ET5+ CT5) exceeds the upper limit, the thickness of the fifth lens is large, and the lens is difficult to machine and form due to the biconcave lens.
In some embodiments, the wide-angle lens satisfies the following conditional expression:
0.04<SD45/CT5<0.5；（11）
where SD45 denotes the distance on the optical axis between the image-side surface of the fourth lens and the object-side surface of the fifth lens, and CT5 denotes the center thickness of the fifth lens. When the conditional expression (11) is satisfied, the distance between the fourth lens element and the fifth lens element is properly adjusted, which is helpful to shorten the total length of the optical system, maintain the miniaturization thereof, satisfy the lens manufacturing and molding, and improve the manufacturing yield.
In some embodiments, the wide-angle lens satisfies the following conditional expression:
1.2<EPDI/IH<1.35；（12）
wherein, EPDI represents the clear aperture of the wide-angle lens, and IH represents the actual half-image height of the wide-angle lens. When the conditional expression (12) is satisfied, the reasonable balance between the large light flux amount and the large imaging surface of the lens can be realized, so that the lens has a large aperture and a high resolving power.
In some embodiments, the wide-angle lens satisfies the following conditional expression:
10°<CRA<13°；（13）
wherein CRA represents an incident angle of a chief ray of the wide-angle lens on an imaging plane. When the conditional expression (13) is met, the chief ray incident angle of the chip can be well matched, the light effect received by the photosensitive area of the chip is effectively improved, and the optimal imaging effect is achieved.
The invention is further illustrated below in the following examples. In various embodiments, the thickness, the curvature radius, and the material selection of each lens in the wide-angle lens are different, and the specific differences can be referred to in the parameter tables of the various embodiments. The following examples are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following examples, and any other changes, substitutions, combinations or simplifications which do not depart from the innovative points of the present invention should be construed as being equivalent substitutions and shall be included within the scope of the present invention.
In the embodiments of the present invention, when the lens in the wide-angle lens is an aspherical lens, the aspherical surface type of the lens satisfies the following equation:
wherein z is the distance rise from the aspheric surface vertex when the aspheric surface is at the position with the height h along the optical axis direction, c is the paraxial curvature of the surface, k is the conic coefficient, A2iIs the aspheric surface type coefficient of 2i order.
First embodiment
Referring to fig. 1, a schematic structural diagram of a wide-angle lens 100 according to a first embodiment of the present invention is shown, where the wide-angle lens 100 sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a second lens L2, a stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and a cover glass G2.
The first lens element L1 has negative power, the object-side surface S1 of the first lens element is convex, and the image-side surface S2 of the first lens element is concave;
the second lens L2 has negative focal power, the object-side surface S3 of the second lens is concave, and the image-side surface S4 of the second lens is convex;
the third lens L3 has positive focal power, the object-side surface S5 of the third lens is convex, and the image-side surface S6 of the third lens is concave;
the fourth lens L4 has positive focal power, and both the object-side surface S7 of the fourth lens and the image-side surface S8 of the fourth lens are convex;
the fifth lens L5 has negative power, and both the object-side surface S9 of the fifth lens and the image-side surface S10 of the fifth lens are concave;
the sixth lens L6 has positive refractive power, and both the object-side surface S11 and the image-side surface S12 of the sixth lens are convex;
the seventh lens L7 has negative power, the object side surface S13 of the seventh lens is convex at the paraxial region and has a point of inflection, and the image side surface S14 of the seventh lens is concave at the paraxial region and has a point of inflection;
the first lens L1, the second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all plastic aspheric lenses, and the third lens L3 is a glass spherical lens.
The parameters related to each lens of the wide-angle lens 100 provided in the present embodiment are shown in table 1.
TABLE 1
In the present embodiment, the surface shape parameters of each aspherical lens in the wide-angle lens 100 are shown in table 2.
TABLE 2
Referring to fig. 2, 3, 4, 5 and 6, a vertical axis chromatic aberration graph, a Modulation Transfer Function (MTF) graph, a defocus graph at a room temperature of 20 ℃, a defocus graph at a low temperature of-30 ℃ and a defocus graph at a high temperature of 70 ℃ of the wide-angle lens 100 are respectively shown. It can be seen from fig. 2 that the vertical axis chromatic aberration at different wavelengths is controlled within 3 microns, which indicates that the vertical axis chromatic aberration of the wide-angle lens 100 is well corrected; as can be seen from fig. 3, the MTF values are all above 0.65, which indicates that the wide-angle lens 100 has excellent resolution performance and good imaging quality; as can be seen from fig. 4, 5, and 6, the imaging quality is good at normal temperature (20 ℃), low temperature (-30 ℃) and high temperature (70 ℃), which indicates that the wide-angle lens 100 has a small temperature drift and good optical thermal stability.
Second embodiment
Referring to fig. 7, a schematic structural diagram of a wide-angle lens 200 according to a second embodiment of the present invention is shown, where the wide-angle lens 200 of the present embodiment is substantially the same as the first embodiment, and mainly differs in parameters such as curvature radius, thickness, and refractive index of each lens.
The parameters related to each lens in wide-angle lens 200 provided in the present embodiment are shown in table 3.
TABLE 3
In the present embodiment, the surface shape parameters of each aspherical lens in the wide-angle lens 200 are shown in table 4.
TABLE 4
Referring to fig. 8 and 9, which are respectively a vertical axis chromatic aberration graph and a Modulation Transfer Function (MTF) graph of the wide-angle lens 200, it can be seen from fig. 8 that the vertical axis chromatic aberration at different wavelengths is controlled within 3 μm, which indicates that the vertical axis chromatic aberration of the wide-angle lens 200 is well corrected; as can be seen from fig. 9, the MTF values are all above 0.5, which indicates that the wide-angle lens 200 has excellent resolution and good imaging quality.
Third embodiment
Referring to fig. 10, a schematic structural diagram of a wide-angle lens 300 according to a third embodiment of the present invention is shown, where the wide-angle lens 300 of the present embodiment is substantially the same as the first embodiment, and mainly differs in parameters such as curvature radius, thickness, and refractive index of each lens.
The parameters of the wide-angle lens 300 provided in this embodiment are shown in table 5.
TABLE 5
In the present embodiment, the surface shape parameters of each aspherical lens in the wide-angle lens 300 are shown in table 6.
TABLE 6
Referring to fig. 11 and 12, which are respectively a vertical axis chromatic aberration graph and a Modulation Transfer Function (MTF) graph of the wide-angle lens 300, it can be seen from fig. 11 that the vertical axis chromatic aberration at different wavelengths is controlled within 3 μm, which indicates that the vertical axis chromatic aberration of the wide-angle lens 300 is well corrected; as can be seen from fig. 12, the MTF values are all above 0.6, which indicates that the wide-angle lens 300 has excellent resolution and good imaging quality.
Please refer to table 7, which shows the optical characteristics of the wide-angle lens provided in the above three embodiments, including the field angle 2 θ, the effective focal length F, the F-number F #, the actual half-height IH, and the related values corresponding to each of the aforementioned conditional expressions.
TABLE 7
As can be seen from the vertical axis chromatic aberration and the MTF curve chart of each embodiment, the vertical axis chromatic aberration and the MTF value of the wide-angle lens in each embodiment are within 3 micrometers, and are all above 0.5, which indicates that the lens provided by the embodiment of the present invention has a large aperture, a large field angle, and a good resolution.
In the wide-angle lens in each embodiment of the invention, the focus offset of the lens is smaller in a low-temperature (-30 ℃) or high-temperature (70 ℃) environment; exemplarily, fig. 4, 5 and 6 are defocus graphs of the wide-angle lens 100 at 20 ℃ at normal temperature, 30 ℃ at low temperature and 70 ℃ at high temperature in the first embodiment of the present invention, respectively, and it can be seen that the variation of the focus offset of the wide-angle lens 100 at low temperature (-30 ℃) relative to the focus offset at normal temperature (20 ℃) and the variation of the focus offset of the wide-angle lens 100 at high temperature (70 ℃) relative to the focus offset at normal temperature (20 ℃) are within ± 0.005 mm; the lenses of other embodiments have smaller focal point offset in high and low temperatures, which shows that the lens of the invention has smaller temperature drift and good optical thermal stability.
In summary, the wide-angle lens provided by the embodiment of the invention effectively corrects the aberration and the temperature drift of the wide-angle lens by reasonably matching the lens shapes, materials and focal power combinations among the lenses, so that the wide-angle lens provided by the embodiment of the invention has the advantages of large aperture, large field angle, good optical thermal stability and high imaging quality, and has good applicability to monitoring electronic devices.
Fourth embodiment
Referring to fig. 14, an imaging device 400 according to a fourth embodiment of the invention is shown, where the imaging device 400 may include an imaging element 410 and a wide-angle lens (e.g., wide-angle lens 100) in any of the embodiments described above. The imaging element 410 may be a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and may also be a CCD (Charge Coupled Device) image sensor.
The imaging device 400 may be a security monitoring device, a vehicle-mounted camera, a panoramic camera, or any other electronic device equipped with the wide-angle lens.
The imaging device 400 provided by the embodiment of the application comprises the wide-angle lens 100, and because the wide-angle lens 100 has the advantages of an ultra-large aperture, a large field angle, high pixels, miniaturization, good thermal stability and relatively low cost, the imaging device 400 with the wide-angle lens 100 also has the advantages of an ultra-large aperture, a large field angle, high pixels, miniaturization, good thermal stability and relatively low cost, and the use requirement of security monitoring equipment can be met.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (11)
1. A wide-angle lens, comprising 7 lenses in the wide-angle lens, in order from an object side to an image plane along an optical axis:
the lens comprises a first lens with negative focal power, a second lens and a third lens, wherein the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;
the second lens is provided with negative focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface;
a diaphragm;
the lens comprises a third lens with positive focal power, wherein the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface;
the fourth lens is provided with positive focal power, 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 lens comprises a fifth lens with negative focal power, wherein the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface;
the sixth lens with positive focal power is characterized in that the object-side surface of the sixth lens is a convex surface, and the image-side surface of the sixth lens is a convex surface;
a seventh lens having a negative optical power, an object side surface of the seventh lens being convex at a paraxial region and having an inflection point, an image side surface of the seventh lens being concave at a paraxial region and having an inflection point;
the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are plastic aspheric lenses, and the third lens is a glass spherical lens;
the wide-angle lens meets the following conditional expression:
0.9≤F#≤1.0；
1.1<f/IH<1.2；
wherein F # represents an F-number of the wide-angle lens, F represents an effective focal length of the wide-angle lens, and IH represents an actual half-image height of the wide-angle lens.
2. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:
9.0mm<f*tanθ<9.5mm；
where f denotes an effective focal length of the wide-angle lens, and θ denotes a half field angle of the wide-angle lens.
3. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:
1.95<(SAG11+SAG12)/CT1<2.1；
wherein SAG11 represents the saggital height of the object side of the first lens, SAG12 represents the saggital height of the image side of the first lens, and CT1 represents the center thickness of the first lens.
4. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:
0.4<CT1/CT3<1.0；
wherein CT1 represents the center thickness of the first lens and CT3 represents the center thickness of the third lens.
5. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:
0.5<R32/f3<3.0；
0.1<R31/R32<0.8；
0.001mm/℃<f3*(dn/dt)3<0.003mm/℃；
wherein R31 represents the curvature radius of the object side surface of the third lens, R32 represents the curvature radius of the image side surface of the third lens, f3 represents the effective focal length of the third lens, and (dn/dt)3 represents the temperature coefficient of the refractive index of the material of the third lens at 20-70 ℃.
6. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:
1.35<(YR71+YR72)/IH<1.50；
wherein, YR71Denotes a perpendicular distance, Y, of an inflection point on an object-side surface of the seventh lens element from an optical axisR72And IH represents the actual half image height of the wide-angle lens.
7. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:
0.25<(ET5-CT5)/(ET5+CT5)<0.45；
wherein ET5 represents the edge thickness of the fifth lens and CT5 represents the center thickness of the fifth lens.
8. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:
0.04<SD45/CT5<0.5；
wherein SD45 represents the distance on the optical axis between the image-side surface of the fourth lens and the object-side surface of the fifth lens, and CT5 represents the center thickness of the fifth lens.
9. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:
1.2<EPDI/IH<1.35；
wherein EPDI represents the clear aperture of the wide-angle lens, and IH represents the actual half-image height of the wide-angle lens.
10. The wide-angle lens of claim 1, wherein the wide-angle lens satisfies the following conditional expression:
10°<CRA<13°；
wherein CRA represents an incident angle of a chief ray of the wide-angle lens on an imaging plane.
11. An imaging apparatus comprising the wide-angle lens according to any one of claims 1 to 10, and an imaging element for converting an optical image formed by the wide-angle lens into an electrical signal.
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| CN101373261B (en) * | 2007-08-22 | 2010-09-29 | 鸿富锦精密工业（深圳）有限公司 | Wide-angle lens and vehicle apparatus using the same |
| US9354431B2 (en) * | 2014-06-30 | 2016-05-31 | Calin Technology Co., Ltd. | Zoom lens |
| JP6732411B2 (en) * | 2015-06-26 | 2020-07-29 | 京セラ株式会社 | Imaging lens and imaging device |
| KR20180070870A (en) * | 2016-12-19 | 2018-06-27 | 엘지이노텍 주식회사 | Image pickup lens, camera module and digital device including the same |
| CN112711127A (en) * | 2021-01-12 | 2021-04-27 | 天津欧菲光电有限公司 | Imaging system, lens module and electronic equipment |
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