Large-aperture wide-spectrum imaging lens and electronic equipment

Abstract

The invention discloses a large-aperture wide-spectrum imaging lens and electronic equipment. The lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens from the object side to the image side. The first lens has positive diopter, and the object side face of the first lens is a convex face. The second lens has positive diopter, the object side surface is a convex surface, and the image side surface is a convex surface; the third lens has negative diopter, the object side surface is a concave surface, and the image side surface is a concave surface; the fourth lens has positive diopter, the object side surface is a concave surface, and the image side surface is a convex surface; the fifth lens has negative diopter, the object side surface is a concave surface, and the image side surface is a concave surface; the sixth lens has positive diopter, the object side surface is a convex surface, and the image side surface is a convex surface; and the seventh lens has negative diopter, the object side surface is a concave surface, the image side surface is a concave surface and the like. According to the invention, large-aperture imaging is realized by selecting a large-aperture initial structure and setting a required clear aperture parameter. A wide spectrum wavelength is adopted as the wavelength of the system, wavelength weights are set on a sensor response curve according to different wavelengths, visible and infrared defocusing amounts are considered, meanwhile, visible and infrared multi-structure configurations are additionally arranged to observe the imaging quality condition, and the nine-piece and six-group optical system is designed.

Description

Technical Field

[0001] The present invention relates to the technical field of wide-spectrum imaging lenses, and in particular to a large-aperture wide-spectrum imaging lens and electronic equipment. Background Art

[0002] Low-light-level night vision optical technology refers to a type of high-tech technology that uses natural nighttime light such as weak moonlight, starlight, atmospheric glow, and Milky Way light as illumination to detect, observe, identify, locate, record, and monitor targets under low illumination or weak radiation intensity of non-visible light. However, conventional low-light-level night vision lenses currently have at least one of the following disadvantages:

[0003] 1. The existing low-light-level night vision lens has a relatively small aperture and poor night vision imaging effect.

[0004] 2. The existing low-light-level night vision lenses have a small spectral range and the imaging quality of different spectra varies.

[0005] 3. The existing low-light-level night vision lens has a short focal length and low resolution, so the detected objects are not clear enough and it is difficult to distinguish the details;

[0006] 4. The existing low-light-level night vision lens is large in size, long in total length, heavy in weight, and cannot meet the requirements of miniaturization and lightweighting;

[0007] 5. The existing low-light-level night vision lens has large image distortion and cannot accurately reflect the true shape of the object.

[0008] 6. Existing low-light-level night vision lenses are greatly affected by temperature changes. Under high and low temperatures, the imaging surface position shifts and the image quality becomes blurred; Summary of the invention

[0009] In view of this, the purpose of the present invention is to provide a wide spectrum imaging lens and an electronic device. The lens can solve at least one technical disadvantage mentioned in the background technology.

[0010] According to one aspect of the present invention, a large aperture wide spectrum imaging lens is provided, which comprises, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens:

[0011] The first lens has positive refractive power and its object side surface is convex;

[0012] The second lens has positive refractive power, an object side surface is convex, and an image side surface is convex;

[0013] The third lens has negative refractive power, and its object side surface is concave and its image side surface is concave;

[0014] The fourth lens has positive refractive power, an object side surface is concave, and an image side surface is convex;

[0015] The fifth lens element has negative refractive power, and its object side surface is concave and its image side surface is concave;

[0016] The sixth lens has positive refractive power, and its object-side surface is convex, and its image-side surface is convex;

[0017] The seventh lens element has negative refractive power, and its object side surface is concave and its image side surface is concave;

[0018] The eighth lens has positive refractive power, and its object-side surface is convex, and its image-side surface is convex;

[0019] The ninth lens element has negative refractive power, and its object side surface is concave and its image side surface is concave;

[0020] The image side surface of the second lens and the object side surface of the third lens are glued together to form a first glued lens;

[0021] The image side surface of the fourth lens and the object side surface of the fifth lens are glued together to form a second glued lens;

[0022] The image side surface of the sixth lens and the object side surface of the seventh lens are glued together to form a third glued lens.

[0023] In the above technical solution, large aperture imaging is achieved by selecting the initial structure of large aperture and setting the required aperture parameters. A wide spectrum wavelength is used as the wavelength of the system, and wavelength weights are set in the sensor response curve according to different wavelengths, taking into account the defocus of visible and infrared, and setting additional multiple structures such as visible and infrared to observe the imaging quality, and designing the above 9-piece 6-group optical system.

[0024] In some embodiments, the lens satisfies the following condition:

[0025] 1.0<|f1 / f|<2.0

[0026] 0.4<|f2 / f|<1.5

[0027] 0.2<|f3 / f|<1.2

[0028] 0.6<|f4 / f|<1.8

[0029] 0.2<|f5 / f|<1.3

[0030] 0<|f6 / f|<1.0

[0031] 0.1<|f7 / f|<1.1

[0032] 0<|f8 / f|<1.0

[0033] 0<|f9 / f|<1.0

[0034] In the formula, f1, f2, f3, f4, f5, f6, f7, f8, f9, and f are respectively the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens and the focal length of the lens.

[0035] In the above technical solution, the overall optical system is scaled to increase the system focal length value, improve the object side resolution capability, and at the same time reasonably distribute the light focal length, reduce the system residual spherical aberration, and match it with a sensor with a pixel level of about 1 million to improve the image quality.

[0036] In some embodiments, the lens satisfies the following condition:

[0037] 0.9 <Fno<20.0

[0038] 2.0 <f / y<8.0

[0039] Wherein, Fno is the F-Number of the lens, and y is the half image height of the imaging surface of the lens.

[0040] In the above technical solution, large-light night vision imaging is achieved, and at the same time it has the advantages of long detection distance and high detection accuracy.

[0041] In some embodiments, the lens satisfies the following condition:

[0042] WD≥0.5m

[0043] △FB>2.0mm

[0044] Wherein, WD is the working distance of the lens, and ΔFB is the change in the back intercept of the lens.

[0045] In the above technical solution, the working distance range is wide and the rear distance changes appropriately, which can meet the requirements of miniaturized focusing.

[0046] In some embodiments, the lens satisfies the following condition:

[0047] 1.0 <TTL / f<2.0

[0048] 0.4 <D1 / f<1.3

[0049] Wherein, TTL is the total optical length of the imaging lens, and D1 is the effective aperture of the first lens of the optical system.

[0050] In the above technical solution, the optical system has the advantages of short overall length and small external diameter, which can well meet the needs of miniaturization and lightweight.

[0051] In some embodiments, the eighth lens is a low melting point aspheric lens, and the lens satisfies the following conditional formula:

[0052] 0 <f8<30mm

[0053] 1.7 <Nd8<2.0

[0054] 30.0 <Vd8<50.0

[0055] In the formula, f8 is the focal length of the eighth lens of the imaging lens, Nd8 is the refractive index of the eighth lens brand, and Vd8 is the Abbe coefficient of the eighth lens brand.

[0056] In the above technical solution, the aspheric surface is introduced to reduce the residual spherical aberration of the system. At the same time, the total length and outer diameter of the optical system can be effectively reduced, the weight of the lens can be reduced, the field curvature of the entire system is relatively small to meet the actual use requirements, and the optical imaging quality is improved.

[0057] In some embodiments, the second lens and the sixth lens are both made of glass material having a negative refractive index temperature coefficient dn / dT.

[0058] In the above technical solution, the second and sixth lenses use a glass brand with a negative refractive index temperature coefficient dn / dT, and adopt a multi-temperature structure athermal design to ensure that the imaging surface position changes little and the image quality is clear within the temperature range of -40°C to +85°C.

[0059] In some embodiments, the lens satisfies the following condition:

[0060] 0 <Optical Distortion<1.5%

[0061] Wherein, Optical Distortion is the relative optical distortion of the lens.

[0062] In the above technical solution, by adding multiple fields of view and coordinating the distortions of different lenses, the relative optical distortion of the lens is controlled within a smaller numerical range, thereby reducing the degree of distortion of the captured image.

[0063] In some embodiments, the lens satisfies the following condition:

[0064] -4.0 <f c1 / f<-2.0

[0065] -3.0 <f c2 / f<-0.5

[0066] 0.6 <f c3 / f<2.2

[0067] In the formula, fc1 、f c2 、f c3 are the focal lengths of the first cemented lens, the second cemented lens, and the third cemented lens respectively.

[0068] In the above technical solution, three groups of double cemented lenses are used to correct the chromatic aberration of the wide spectrum optical system, so that the remaining chromatic aberration is within a smaller numerical range, thereby improving the chromatic aberration performance of the actual image.

[0069] According to another aspect of the present invention, an electronic device is provided, according to the above-mentioned large aperture wide spectrum imaging lens; and

[0070] The image sensor is configured to receive the image formed by the large aperture wide spectrum imaging lens.

[0071] In the above technical solution, the advantages of the electronic device rely on the large aperture and wide spectrum imaging lens, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0073] Figure 1 This is a schematic structural diagram of Example 1 of a large aperture wide spectrum imaging lens according to the present invention;

[0074] Figure 2 is an MTF curve diagram of Example 1 of a large aperture wide spectrum imaging lens of the present invention;

[0075] Figure 3 is a field curvature and distortion curve diagram of Example 1 of a large aperture wide spectrum imaging lens of the present invention;

[0076] Figure 4 This is a star point diagram of Example 1 of a large aperture wide spectrum imaging lens of the present invention;

[0077] Figure 5 is a chromatic aberration diagram of Example 1 of a large aperture wide spectrum imaging lens of the present invention;

[0078] Figure 6 is a spherical aberration diagram of Example 1 of a large aperture wide spectrum imaging lens of the present invention;

[0079] Figure 7 is a relative illumination diagram of Example 1 of a large aperture wide spectrum imaging lens of the present invention;

[0080] Figure 8 This is an MTF vs Field diagram of Example 1 of a large aperture wide spectrum imaging lens of the present invention.

[0081] Fig. 9 It is a structural diagram of an electronic device example 2 of the present invention. DETAILED DESCRIPTION

[0082] The present invention will be further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention. Similarly, the following examples are only partial embodiments of the present invention rather than all embodiments, and all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0083] The object of the present invention is to provide a large aperture wide spectrum imaging lens and electronic equipment with high optical performance. Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0084] Figure 1 : is a cross-sectional view of a large aperture wide spectrum imaging lens (optical system) according to Example 1. The large aperture wide spectrum imaging lens according to each example is used for an optical device including an imaging device such as a digital camera, a digital still camera, a broadcast camera, a surveillance camera, and an interchangeable lens. In each cross-sectional view, the left side is the object side OBJ and the right side is the image side IMA. In each cross-sectional view, Li represents the i-th lens, and Ci represents the i-th cemented lens. ST represents an aperture (fixed aperture or visible aperture), and a protective lens G. IMA represents an image plane, and in the large aperture wide spectrum imaging lens according to the example, which is used for an optical device including an imaging device such as a digital camera, a digital still camera, a broadcast camera, a surveillance camera, and an interchangeable lens, a solid-state imaging element (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor is arranged on the imaging plane IMA.

[0085] The large aperture wide spectrum imaging lens according to various examples includes, in order from the object side to the image side:

[0086] From the object side to the image side, they are the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, and the ninth lens L9:

[0087] The first lens L1 has positive refractive power, and the object side surface is convex;

[0088] The second lens L2 has positive refractive power, and its object-side surface is convex, and its image-side surface is convex;

[0089] The third lens L3 has a negative refractive power, a concave object-side surface, and a concave image-side surface;

[0090] The fourth lens L4 has positive refractive power, a concave object-side surface, and a convex image-side surface;

[0091] The fifth lens L5 has negative refractive power, a concave object-side surface, and a concave image-side surface;

[0092] The sixth lens L6 has positive refractive power, and its object-side surface is convex and its image-side surface is convex;

[0093] The seventh lens L7 has negative refractive power, a concave object-side surface, and a concave image-side surface;

[0094] The eighth lens L8 has positive refractive power, and its object-side surface is convex and its image-side surface is convex;

[0095] The ninth lens L9 has negative refractive power, a concave object-side surface, and a concave image-side surface;

[0096] The image side surface of the second lens L2 and the object side surface of the third lens L3 are cemented together to form a first cemented lens C1; the image side surface of the fourth lens L4 and the object side surface of the fifth lens L5 are cemented together to form a second cemented lens C2; the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 are cemented together to form a third cemented lens C3.

[0097] The seventh lens is a low melting point aspheric lens, and the second lens and the sixth lens are both made of glass material with a negative refractive index temperature coefficient dn / dT.

[0098] See also Figure 1 The optical system consists of 9 lenses and 6 groups. The aperture is located between the seventh lens L7 and the eighth lens L8. There is enough space between the seventh lens L7 and the eighth lens L8 to place the variable aperture component. The light is converged by the first lens L1, diverged by the first cemented lens C1 and the second cemented lens C2, converged by the third cemented lens C3, and then converged by the seventh lens L7, and imaged on the image plane by the eighth lens L8. The aperture of the entire system is from large to small, and the aperture of the first lens L1 limits the outer diameter of the entire lens. The use of an aspherical surface in the eighth lens L8 can effectively reduce the total length and outer diameter of the optical system, making the field curvature of the entire system relatively small to meet actual usage needs, while improving the optical imaging quality.

[0099] The large aperture wide spectrum imaging lens according to each example may satisfy at least one of the following setting conditions 1) to 7):

[0100] 1)1.0<|f1 / f|<2.0; 0.4<|f2 / f|<1.5; 0.2<|f3 / f|<1.2; 0.6<|f4 / f|<1.8; 0.2<|f5 / f|<1.3;

[0101] 0<|f6 / f|<1.0; 0.1<|f7 / f|<1.1; 0<|f8 / f|<1.0; 0<|f9 / f|<1.0

[0102] 2) 0.9 <Fno<20.0;2.0<f / y<8.0

[0103] 3)WD≥0.5m; △FB>2.0mm;

[0104] 4)1.0 <TTL / f<2.0;0.4<D1 / f<1.3;

[0105] 5)0 <f8<30mm;1.7<Nd8<2.0;30.0<Vd8<50.0

[0106] 6)0 <Optical Distortion<1.5%

[0107] 7)-4.0 <f c1 / f<-2.0;-3.0 <f c2 / f<-0.5;0.6 <f c3 / f<2.2

[0108] In the above conditional formula, f1, f2, f3, f4, f5, f6, f7, f8, f9, f are respectively the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens and the imaging lens; WD is the working distance of the imaging lens, △FB is the change in the back focus of the imaging lens; TTL is the total optical length of the imaging lens, D1 is the effective aperture of the first lens of the optical system; f7 is the focal length of the seventh lens of the imaging lens, Nd7 is the refractive index of the seventh lens brand, Vd7 is the Abbe coefficient of the seventh lens brand; OpticalDistortion is the relative optical distortion of the imaging lens; f c1 、f c2 、f c3 are the focal lengths of the first cemented lens, the second cemented lens, and the third cemented lens respectively.

[0109] Conditional formula 1) defines the ratio of the nine lenses to the total focal length of the imaging lens. By setting the conditions appropriately, the optical system is scaled as a whole, the system focal length is increased, the object side resolution is improved, and the optical focal length is reasonably allocated to reduce the residual spherical aberration of the system. With a sensor with a pixel level of about 1 million, the image quality is improved. If the above nine parameter values ​​are higher than the upper limit, the focal length of each lens is too small to correct the aberration. However, if it is lower than the lower limit, the focal length of each lens is too large, the sensitivity of the lens increases, and it is not conducive to mass assembly. In addition, in order to reliably obtain the effect of conditional formula 1), it is more preferred to set the value of conditional formula 1) to |f1 / f|=1.4, |f2 / f|=1.0, |f3 / f|=0.4, |f4 / f|=1.2, |f5 / f|=0.7, |f6 / f|=0.5, |f7 / f|=0.6, |f8 / f|=0.5, |f9 / f|=0.6.

[0110] Conditional formula 2) defines the F-Number value of the imaging lens, the ratio of the half-image height of the imaging surface to the focal length. By setting the conditions appropriately, weak light can be detected and imaged, and a large-light low-light night vision imaging effect can be achieved to meet nighttime use. If the above two parameter values ​​are higher than the upper limit, the aperture is small and the exposure time is long, which cannot meet the requirements of fast imaging in a low-light environment. The imaging surface is small, and the details in a low-light environment are insufficient. However, if it is lower than the lower limit, the aperture of the optical system increases, and the complexity of the system is further increased, which cannot meet the requirements of miniaturization. The focal length becomes smaller, the field of view becomes larger, and the details of the object being measured cannot be detected. In addition, in order to reliably obtain the effect of conditional formula 2), it is more preferred to set the value of conditional formula 2) to Fno=1.0, f / y=5.6.

[0111] Conditional formula 3) defines the working distance of the imaging lens and the change in the back intercept of the imaging lens. By setting the conditions appropriately, the imaging range from 0.5m to infinity is satisfied and the focusing distance is appropriate. If the above two parameter values ​​are lower than the lower limit, the working range of the optical system is small, the focusing movement is small, and the focus is sensitive. In addition, in order to reliably obtain the effect of conditional formula 3), it is more preferred to set the value of conditional formula 3) to △FB = 2.6mm when WD = 0.8m to infinity.

[0112] Conditional formula 4) defines the ratio of the total optical length of the imaging lens to the focal length of the imaging lens, and the ratio of the effective aperture of the first lens L1 to the focal length of the imaging lens. By setting the conditions appropriately, the optical system has the advantages of a short total length and a small external aperture, which can well meet the requirements of miniaturization and lightweight. If the above two parameter values ​​are higher than the upper limit, the total length and large aperture of the optical system are not conducive to miniaturization. However, if it is lower than the lower limit, the imaging quality of the optical system is poor and the field of view is too small. In addition, in order to reliably obtain the effect of conditional formula 4), it is more preferred to set the value of conditional formula 4) to TTL / f=1.54 and D1 / f=0.95.

[0113] Conditional formula 5) defines the focal length, refractive index, and Abbe coefficient of the eighth lens. By setting the conditions appropriately, an aspheric surface is introduced to reduce the residual spherical aberration of the system. At the same time, the total length and outer diameter of the optical system can be effectively reduced, the weight of the lens can be reduced, and the field curvature of the entire system is relatively small to meet the actual use requirements, while improving the optical imaging quality. If the above three parameter values ​​are higher than the upper limit, the lens focal length is insufficient, the residual aberration of the optical system is large, and the material price is expensive. However, if it is lower than the lower limit, the lens acts as a divergent light, and the light cannot reach the image plane normally. In addition, in order to reliably obtain the effect of conditional formula 5), ​​it is more preferred to set the value of conditional formula 5) to f8 = 0.5 mm (when the total focal length f of the optical system is normalized to 1 mm), Nd8 = 1.8, and Vd8 = 41.

[0114] Conditional formula 6) defines the relative optical distortion. By setting the conditions appropriately, by adding multiple fields of view, and coordinating the distortion of different lenses, the relative optical distortion of the lens is controlled within a smaller numerical range, so that the degree of deformation of the captured image is small. If it is higher than the upper limit, the degree of deformation of the optical system image is large, affecting the actual viewing effect. However, if it is lower than the lower limit, barrel distortion will occur. In addition, in order to reliably obtain the effect of conditional formula 6), it is more preferred to set the value of conditional formula 6) to 1.3%.

[0115] Conditional formula 7) defines the focal length of the three groups of cemented lenses. By setting the conditions appropriately, the wide spectrum chromatic aberration of the optical system is balanced and the chromatic aberration performance is improved. If the above three parameter values ​​are higher than the upper limit, the first and second lenses are over-corrected and become sensitive. The third cemented lens is under-corrected. However, if it is lower than the lower limit, the correction ability of the first and second cemented lenses is insufficient, the correction of the third cemented lens is too large, and the lens becomes sensitive. In addition, in order to reliably obtain the effect of conditional formula 7), it is more preferred to set the value of conditional formula 7) to f c1 / f=-3.3,f c2 / f=-1.7,f c3 / f=1.4.

[0116] A detailed description will now be given of a large aperture spectral imaging lens according to an example.

[0117] For the optical structure of Example 1, please refer to Figure 1 , the specific parameters of Example 1 are shown in Table 1 below. In Example 1, the focal length of the lens f'=1mm, the aperture F=1.0, the field of view angle FOV=20°, and the total optical length TTL=1.54mm. The conditional formula is as follows:

[0118] 1)|f1 / f|=1.4; |f2 / f|=1.0; |f3 / f|=0.7; |f4 / f|=1.2; |f5 / f|=0.7; |f6 / f|=0.5; |f7 / f|=0.6; |f8 / f|=0.5;

[0119] |f9 / f|=0.6;

[0120] 2) Fno = 1.0; f / y = 5.6

[0121] 3)WD=0.8~∞; △FB=2.6;

[0122] 4) TTL = 1.54; D1 / f = 0.95;

[0123] 5) f8 = -0.5 mm (optical system focal length is scaled to f = 1 mm); Nd8 = 1.8; Vd8 = 41

[0124] 6)Optical Distortion=1.3%;

[0125] 7)f c1 / f=-3.3;f c2 / f=-1.7;f c3 / f=1.4

[0126] Table 1 Example 1 Parameters

[0127] Face number type Radius of curvature thickness Material Refractive Index Dispersion coefficient focal length 1 First lens 0.904 0.17 Glass 1.7 41 1.4 2 10.901 0.04 3 Second lens 0.664 0.20 Glass 1.6 68 1.0 4 The third lens -3.295 0.03 Glass 1.7 30 -0.7 5 0.532 0.12 6 The fourth lens -2.406 0.11 Glass 1.6 59 1.2 7 Fifth lens -0.567 0.02 Glass 1.8 48 -0.7 8 8.373 0.00 9 The sixth lens 0.473 0.21 Glass 1.6 69 0.5 10 Seventh lens -0.652 0.16 Glass 1.5 64 -0.6 11 0.562 0.04 12 ST Infinity 0.05 13 The eighth lens 0.536 0.19 Low melting point glass 1.8 41 0.5 14 -1.278 0.01 15 The ninth lens -0.636 0.07 Glass 1.6 43 -0.6 16 0.741 0.05 17 Protective glass Infinity 0.02 Glass 1.6 64 18 Infinity 0.04 IMA Imaging surface Infinity

[0128] Table 2 Aspheric coefficients of the eighth lens in Example 1

[0129] Surface number K A4 A6 A8 A10 13 0.31 -3.471E+00 -6.926E+01 2.905E+02 -2.291E+04 14 -149.97 -8.552E+00 6.322E+01 -2.832E+03 2.412E+04

[0130] The eighth lens in this embodiment is an aspherical lens, and both the object side and the image side of the lens are aspherical. The equation of the surface curve of the aspherical lens is expressed as follows:

[0131]

[0132] Where, z: the depth of the aspheric surface (the vertical distance between the point on the aspheric surface that is y away from the optical axis and the tangent plane tangent to the vertex on the aspheric optical axis); c: the curvature of the vertex of the aspheric surface (the vertex curvature); K: the conic constant; Radial distance; r n : Normalization radius (NRADIUS); u: a m : mth order Qcon The coefficient (the m th Q con coefficient); mth order Q con Polynomial th Q con polynomial).

[0133] See also Figure 2 , the MTF curve of Example 1, the horizontal axis is the frequency, the unit is line pair. The vertical axis is the MTF value, the unit is none. From the above figure, we can see that the MTF curves of each field of view are relatively concentrated, and the curves are relatively straight. At 60Lp / mm, the MTF is mainly concentrated around the value of 0.3. The imaging quality is good, which meets the requirements of the matching sensor and has a good imaging effect.

[0134] See also Figure 3 , the field curvature distortion diagram of the optical system of Example 1, the left figure is the field curvature diagram, the horizontal axis is the field curvature value, the unit is millimeter; the vertical axis is the normalized field of view, the unit is infinite rigid. It can be intuitively concluded from the figure: the field curvature of the lens is within 0.1mm. The right figure is the optical relative distortion diagram, the horizontal axis is the percentage relative optical distortion value, the unit is %; the vertical axis is the normalized field of view, the unit is infinite rigid. It can be intuitively concluded from the figure: the relative optical distortion of the lens is about 1.5%, which can meet the requirements for high-precision measurement.

[0135] See also Figure 4 , the star point diagram of the optical system of Example 1. It can be seen from the figure that the star point diffusion spot of the lens is well optimized and the star point shape is circular. The RMS radius size of the star point is 7.871um, which can match the required requirements of the sensor. The geometric radius size is 48.256um, which can meet the current requirements.

[0136] See also Figure 5 , the chromatic aberration diagram of the optical system of Example 1, the horizontal axis is the chromatic aberration value, the unit is micrometer; the vertical axis is the normalized field of view, the unit is infinite. The vertical lines on the left and right sides are the range of the Ariban radius value. It can be concluded from the figure that the maximum chromatic aberration of the lens in the entire field of view of 434nm-1000nm is about positive 7um, which belongs to the wavelength of 546nm. The minimum value is negative 6um, which belongs to the wavelength of 1000um. The optical system has good chromatic aberration correction, which is comparable to the pixel size, and the color reproduction is high.

[0137] See also Figure 6 , the spherical aberration diagram of the optical system of Example 1. It can be seen from the figure that the maximum spherical aberration is around 0.12mm, and the 434nm wavelength moves to the right as the aperture increases, intersecting with the 1000nm wavelength at 0.6 aperture. Other wavelengths gather together as the aperture increases.

[0138] See also Figure 7 , the relative illumination diagram of the optical system of Example 1. It can be seen from the figure that the relative illumination of the full field of view of the optical system is greater than 50%, the brightness of the image is uniform, and there is no obvious dark corner phenomenon at the edge.

[0139] See also Figure 8 , the optical system of Example 1 is the MTF vs Field diagram. It can be seen from the figure that the meridian and sagittal rays are closely intertwined, indicating that the optical system has good astigmatism correction in the entire field of view. The imaging lens has balanced imaging in the meridian and sagittal directions without deviation. The central field of view will facilitate the focusing of the imaging system and find the best image plane due to the full field of view. At 30Lp / mm, the central MTF is greater than 0.7, and the full field MTF is greater than 0.4. At 60Lp / mm, the central MTF is greater than 0.4, and the full field MTF is around 0.1.

[0140] Based on Example 1, this case has the following specific advantages:

[0141] 1. By selecting the initial structure of large aperture and setting the required aperture parameters, large aperture imaging can be achieved.

[0142] 2. Use a wide spectrum wavelength as the wavelength of the system, set the wavelength weight in the sensor response curve according to different wavelengths, take into account the defocus of visible and infrared, and set up additional multiple structures such as visible and infrared to observe the imaging quality, so as to form an optical system that meets the wavelength setting requirements.

[0143] 3. By scaling the entire optical system, increasing the system focal length, improving the object side resolution, and rationally distributing the optical focal length, introducing aspherical surfaces, reducing the system's residual spherical aberration, and matching it with a sensor with a pixel level of about 1 million, the image quality can be improved.

[0144] 4. By using aspherical surfaces, the number of glass lenses can be reduced, the lens size can be reduced, and the lens weight can be reduced.

[0145] 5. By adding multiple fields of view and coordinating the distortion of different lenses, the relative optical distortion of the lens can be controlled within a smaller numerical range, thereby reducing the degree of distortion of the captured image.

[0146] 6. The second and sixth lenses use a glass grade with a negative refractive index temperature coefficient dn / dT and a multi-temperature structure athermal design, which ensures that the imaging surface position changes little and the image quality is clear within the temperature range of -40℃ to +85℃.

[0147] Example 2

[0148] Reference Fig. 9 , a description will be given of an electronic device A according to Example 2 of the present invention. Fig. 9is a schematic diagram of an electronic device (camera) using any of the large-aperture wide-spectrum imaging lenses according to Example 1 for an imaging optical system.

[0149] exist Fig. 9 , reference numeral A2 denotes an electronic device body, and reference numeral A1 denotes an imaging optical system (interchangeable lens) including any one of the large-aperture wide-spectrum imaging lenses according to Example 1. Reference numeral A3 denotes an image sensor (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor, which is built into the camera body A2 and receives light (optical image formed by the imaging optical system A1) from the imaging optical system A1 and performs photoelectric conversion.

[0150] By using the large-aperture wide-spectrum imaging lens according to any of Example 1 for an electronic device such as a digital still camera or the like, an electronic device having a large-aperture wide-spectrum imaging lens with high optical performance can be obtained.

[0151] Various examples may provide electronic devices having high optical performance.

[0152] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A large aperture wide spectrum imaging lens, characterized in that: From the object side to the image side, they are the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens: The first lens has positive refractive power and a convex object side surface; The second lens has positive refractive power, and its object side surface is convex, and its image side surface is convex; The third lens has negative refractive power, and its object side surface is concave and its image side surface is concave; The fourth lens has positive refractive power, an object side surface is concave, and an image side surface is convex; The fifth lens element has negative refractive power, and its object side surface is concave and its image side surface is concave; The sixth lens has positive refractive power, and its object-side surface is convex, and its image-side surface is convex; The seventh lens element has negative refractive power, and its object side surface is concave and its image side surface is concave; The eighth lens has positive refractive power, and its object-side surface is convex, and its image-side surface is convex; The ninth lens element has negative refractive power, and its object side surface is concave and its image side surface is concave; The image side surface of the second lens and the object side surface of the third lens are glued together to form a first glued lens; The image side surface of the fourth lens and the object side surface of the fifth lens are glued together to form a second glued lens; The image side surface of the sixth lens and the object side surface of the seventh lens are glued together to form a third glued lens.

2. The large aperture wide spectrum imaging lens according to claim 1, characterized in that: The lens satisfies the following conditional formula: 1.0<|f1 / f|<2.0 0.4<|f2 / f|<1.5 0.2<|f3 / f|<1.2 0.6<|f4 / f|<1.8 0.2<|f5 / f|<1.3 0<|f6 / f|<1.0 0.1<|f7 / f|<1.1 0<|f8 / f|<1.0 0<|f9 / f|<1.0 In the formula, f1, f2, f3, f4, f5, f6, f7, f8, f9, and f are respectively the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens and the focal length of the lens.

3. The large aperture wide spectrum imaging lens according to claim 1, characterized in that: The lens satisfies the following conditional formula: 0.9 <Fno<20.0 2.0 <f / y<8.0 Wherein, Fno is the F-Number of the lens, and y is the half image height of the imaging surface of the lens.

4. The large aperture wide spectrum imaging lens according to claim 1, characterized in that: The lens satisfies the following conditional formula: WD≥0.5m △FB>2.0mm Wherein, WD is the working distance of the lens, and ΔFB is the change in the back intercept of the lens.

5. The large aperture wide spectrum imaging lens according to claim 1, characterized in that: The lens satisfies the following conditional formula: 1.0 <TTL / f<2.0 0.4 <D1 / f<1.3 Wherein, TTL is the total optical length of the imaging lens, and D1 is the effective aperture of the first lens of the optical system.

6. The large aperture wide spectrum imaging lens according to claim 1, characterized in that: The eighth lens is a low melting point aspheric lens, and the lens satisfies the following conditional formula: 0 <f8<30mm 1.7 <Nd8<2.0 30.0 <Vd8<50.0 In the formula, f8 is the focal length of the eighth lens of the imaging lens, Nd8 is the refractive index of the eighth lens brand, and Vd8 is the Abbe coefficient of the eighth lens brand.

7. The large aperture wide spectrum imaging lens according to claim 1, characterized in that: The second lens and the sixth lens are both made of glass material with a negative refractive index temperature coefficient dn / dT.

8. The large aperture wide spectrum imaging lens as claimed in claim 1, characterized in that: The lens satisfies the following conditional formula: 0 <Optical Distortion<1.5% Wherein, Optical Distortion is the relative optical distortion of the lens.

9. The large aperture wide spectrum imaging lens according to claim 1, characterized in that: The lens satisfies the following conditional formula: -4.0<f c1 / f<-2.0 -3.0<f c2 / f<-0.5 0.6<f c3 / f<2.2 In the formula, f c1 、f c2 、f c3 are the focal lengths of the first cemented lens, the second cemented lens, and the third cemented lens respectively.

10. An electronic device, characterized in that: A large aperture wide spectrum imaging lens according to any one of claims 1 to 9; and The image sensor is configured to receive the image formed by the large aperture wide spectrum imaging lens.

Images