A large-aperture wide-spectrum imaging lens and electronic device

Abstract

This invention discloses a large-aperture, wide-spectrum imaging lens and electronic device. The lens, from the object side to the image side, consists of 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: the first lens has positive refractive power and a convex object-side surface; the second lens has positive refractive power and both the object-side and image-side surfaces are convex; the third lens has negative refractive power and both the object-side and image-side surfaces are concave; the fourth lens has positive refractive power, both the object-side and image-side surfaces are concave; the fifth lens has negative refractive power and both the object-side and image-side surfaces are concave; the sixth lens has positive refractive power and both the object-side and image-side surfaces are convex; the seventh lens has negative refractive power and both the object-side and image-side surfaces are concave, and so on. This invention achieves large-aperture imaging by selecting a large-aperture initial structure and setting the required aperture parameters. A wide-spectrum wavelength is used as the system wavelength. Wavelength weights are set on the sensor response curve according to different wavelengths, taking into account the defocus of visible and infrared. At the same time, multiple structural configurations for visible and infrared are set to observe the imaging quality. The above-mentioned optical system with 9 elements and 6 groups is designed.

Description

Technical Field

[0001] This invention relates to the field of wide-spectrum imaging lens technology, and more particularly to a large-aperture wide-spectrum imaging lens and electronic device. Background Art

[0002] Low-light night vision optical technology refers to a class of high-tech methods that utilize the faint nighttime light, such as moonlight, starlight, atmospheric glow, and Milky Way, to detect, observe, identify, locate, record, and monitor targets under low-light or non-visible light radiation conditions. However, conventional low-light night vision lenses currently suffer from at least one of the following drawbacks:

[0003] 1. Existing low-light night vision lenses have relatively small apertures, resulting in poor night vision imaging.

[0004] 2. Existing low-light night vision lenses have limited spectral coverage and inconsistent imaging quality across different frequencies.

[0005] 3. Existing low-light night vision lenses have short focal lengths and relatively low resolutions, making it difficult to detect objects clearly and distinguish details.

[0006] 4. Existing low-light night vision lenses are large in size, long in length, and heavy in weight, which cannot meet the requirements for miniaturization and weight reduction.

[0007] 5. Existing low-light night vision lenses suffer from significant image distortion and cannot accurately reflect the true shape of objects.

[0008] 6. Existing low-light night vision lenses are greatly affected by temperature changes. At high and low temperatures, the position of the imaging surface shifts, resulting in blurred image quality. Summary of the Invention

[0009] In view of this, the object of the present invention is to provide a broadband imaging lens and electronic device. This lens can at least solve one of the technical disadvantages mentioned in the background art.

[0010] According to one aspect of the present invention, a large-aperture broadband imaging lens is provided, comprising, 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, and the object side is convex, as is the image side;

[0013] The third lens has negative refractive power, and both the object-side and image-side surfaces are concave.

[0014] The fourth lens has positive refractive power, with a concave object side and a convex image side;

[0015] The fifth lens has negative refractive power, and both the object-side and image-side surfaces are concave.

[0016] The sixth lens has positive refractive power, and the object side is convex, as is the image side;

[0017] The seventh lens has negative refractive power, and both the object-side and image-side surfaces are concave.

[0018] The eighth lens has positive refractive power, and the object side and the image side are both convex.

[0019] The ninth lens has negative refractive power, and the object side is concave, as is the image side;

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

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

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

[0023] In the above technical solution, large-aperture imaging is achieved by selecting a large-aperture initial structure and setting the required aperture parameters. A broadband wavelength is used as the system wavelength, and wavelength weights are set according to different wavelengths on the sensor response curve, taking into account both visible and infrared defocusing. Additionally, multiple structural configurations for visible and infrared imaging are set to observe the imaging quality, resulting in the design of the aforementioned 9-element, 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 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, respectively.

[0035] In the above technical solution, by scaling the optical system 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. Combined with a sensor with a resolution of about 1 million pixels, the image imaging quality is improved.

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

[0037] 0.9 <Fno<20.0

[0038] 2.0 <f / y<8.0

[0039] In the formula, Fno is the F-Number of the lens, and y is the half-image height of the imaging plane of the lens.

[0040] The above technical solution achieves high-throughput night vision imaging, while also having 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] In the formula, WD is the working distance of the lens, and △FB is the change in the back clip of the lens.

[0045] The above technical solution has a wide working distance range and appropriate back focus distance variation, 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] In the formula, TTL is the total optical length of the imaging lens, and D1 is the effective aperture of the first element of the optical system.

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

[0051] In some embodiments, the eighth lens is a low-melting-point aspherical lens, and the lens satisfies the following condition:

[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, and Vd8 is the Abbe coefficient of the eighth lens.

[0056] In the above technical solution, aspherical surfaces are introduced to reduce residual spherical aberration in the system. This also effectively reduces the overall length and outer diameter of the optical system, lowers the lens weight, and results in a relatively small field curvature that meets practical application requirements, while simultaneously improving optical imaging quality.

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

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

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

[0060] 0 <Optical Distortion<1.5%

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

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

[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] Where, fc1 f c2 f c3 These 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 sets of cemented doublet lenses are used to correct the chromatic aberration of the broadband optical system, keeping the remaining chromatic aberration within a small range. This improves the chromatic aberration performance in real-world image capture.

[0069] According to another aspect of the present invention, an electronic device is provided, comprising the aforementioned large-aperture broadband imaging lens; and

[0070] An image sensor is configured to receive images formed by the large-aperture broadband imaging lens.

[0071] In the above technical solution, the advantage of this electronic device relies on a large-aperture, wide-spectrum imaging lens, which will not be elaborated here. Attached Figure Description

[0072] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

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

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

[0075] Figure 3 This 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 map of Example 1 of a large aperture wide-spectrum imaging lens of the present invention;

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

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

[0079] Figure 7 This 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] Figure 9 This is a structural diagram of an example 2 of an electronic device according to the present invention. Detailed Implementation

[0082] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the invention. Similarly, the following embodiments are only some, not all, embodiments of the present invention, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0083] The purpose of this invention is to provide a large-aperture, wide-spectrum imaging lens and electronic device with high optical performance. Embodiments according to the invention will now be described in detail with reference to the accompanying drawings.

[0084] Figure 1 This is a cross-sectional view of a large-aperture broadband imaging lens (optical system) according to Example 1. The large-aperture broadband imaging lenses according to the various examples are used in imaging devices such as digital video cameras, digital still cameras, broadcast cameras, surveillance cameras, etc., and in interchangeable-lens optical devices. 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 the aperture stop (fixed aperture stop or visible aperture stop), and G is the protective lens. IMA represents the image plane, and in the large-aperture broadband imaging lens according to the examples used in imaging devices such as digital video cameras, digital still cameras, broadcast cameras, surveillance cameras, etc., and in interchangeable-lens optical devices, solid-state imaging elements (photoelectric conversion elements), such as CMOS image sensors or CCD image sensors, are arranged on the image plane IMA.

[0085] The large-aperture, wide-spectrum imaging lenses, listed in the examples, are arranged from the object side to the image side as follows:

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

[0087] The first lens L1 has positive refractive power and its object-side surface is convex.

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

[0089] The third lens L3 has negative refractive power, and the object side is concave, as is the image side;

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

[0091] The fifth lens L5 has negative refractive power, and the object side is concave, as is the image side;

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

[0093] The seventh lens L7 has negative refractive power, and both the object-side and image-side surfaces are concave.

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

[0095] The ninth lens L9 has negative refractive power, and the object side is concave, as is the image side;

[0096] The image-side surface of the second lens L2 and the object-side surface of the third lens L3 are bonded 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 bonded 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 bonded together to form a third cemented lens C3.

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

[0098] Please see Figure 1 The optical system consists of 9 elements in 6 groups. The aperture stop is located between the seventh lens L7 and the eighth lens L8, with sufficient space between them to accommodate a variable aperture stop component. Light rays converge after passing through the first lens L1, diverge after passing through the first cemented lens C1 and the second cemented lens C2, converge again after passing through the third cemented lens C3, and then converge again through the seventh lens L7 before being imaged onto the image plane by the eighth lens L8. The aperture of the entire system decreases from large to small, with the aperture of the first lens L1 limiting the overall outer diameter of the lens. The eighth lens L8, being aspherical, effectively reduces the overall length and outer diameter of the optical system, resulting in a relatively small field curvature that meets practical application requirements, while simultaneously improving optical image quality.

[0099] The large-aperture broadband imaging lens in each example can 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 conditions, f1, f2, f3, f4, f5, f6, f7, f8, f9, and f are the focal lengths of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens, and the imaging lens, respectively; WD is the working distance of the imaging lens; △FB is the change in the back clip of the imaging lens; TTL is the total optical length of the imaging lens; D1 is the effective aperture of the first element of the optical system; f7 is the focal length of the seventh element of the imaging lens; Nd7 is the refractive index of the seventh element; Vd7 is the Abbe coefficient of the seventh element; Optical Distortion is the relative optical distortion of the imaging lens; f c1 f c2 f c3 These are the focal lengths of the first cemented lens, the second cemented lens, and the third cemented lens, respectively.

[0109] Condition 1) defines the ratio of the focal length of each of the nine lenses to the total focal length of the imaging lens. By appropriately setting the conditions, the optical system is scaled up as a whole, increasing the system focal length and improving object-side resolution. Simultaneously, the optical focal length is rationally allocated, reducing residual spherical aberration. Combined with a sensor of approximately 1 million pixels, this improves image quality. If the values ​​of the nine parameters exceed the upper limit, the optical focal length of each lens is too small to compensate for aberrations. However, if they are below the lower limit, the optical focal length of each lens is too large, increasing lens sensitivity and hindering mass production. Furthermore, to reliably achieve the effect of Condition 1), it is preferable to set the values ​​of Condition 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, and |f9 / f| = 0.6.

[0110] Condition 2) defines the F-Number value of the imaging lens and the ratio of the half-image height to the focal length. By appropriately setting these conditions, it detects weak light and achieves high-aperture low-light night vision imaging, meeting the requirements for nighttime use. If the values ​​of these two parameters are higher than the upper limit, the aperture is small, the exposure time is long, and it cannot meet the requirements for rapid imaging in low-light environments. The imaging surface is small, and the detail representation in low-light environments is insufficient. However, if the values ​​are lower than the lower limit, the aperture of the optical system increases, the system complexity increases further, and it cannot meet the miniaturization requirements. The focal length becomes smaller, the field of view becomes larger, and the details of the measured object cannot be detected. Furthermore, in order to reliably obtain the effect of condition 2), it is more preferable to set the value of condition 2) to Fno = 1.0 and f / y = 5.6.

[0111] Condition 3) defines the working distance of the imaging lens and the change in the back clip of the imaging lens. By appropriately setting the conditions, it satisfies the imaging use in the range from 0.5m to infinity, with an appropriate focusing distance. If the values ​​of the above two parameters are lower than the lower limit, the working range of the optical system is small, the focusing movement is small, and the focusing sensitivity is high. In addition, in order to reliably obtain the effect of condition 3), it is more preferable to set the value of condition 3) to WD = 0.8m to infinity, where ΔFB = 2.6mm.

[0112] Condition 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 appropriately setting these conditions, the optical system has the advantages of short total length and small aperture, which can well meet the requirements of miniaturization and lightweighting. If the values ​​of the above two parameters are higher than the upper limit, the total length and aperture of the optical system are large, which is not conducive to miniaturization. However, if they are 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 condition 4), it is more preferable to set the values ​​of condition 4) to TTL / f = 1.54 and D1 / f = 0.95.

[0113] Condition 5) defines the focal length, refractive index, and Abbe coefficient of the eighth lens. By appropriately setting the conditions, an aspherical surface is introduced to reduce the residual spherical aberration of the system. Simultaneously, it effectively reduces the overall length and outer diameter of the optical system, lowers the lens weight, and results in a relatively small field curvature that meets practical application requirements, while also improving optical imaging quality. If the values ​​of the above three parameters exceed the upper limit, the lens power is insufficient, the residual aberration of the optical system is large, and the materials are expensive. However, if they are below the lower limit, the lens acts as a divergent ray, and the light cannot reach the image plane normally. Furthermore, to reliably obtain the effect of condition 5), it is preferable to set the values ​​of condition 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] Condition 6) defines relative optical distortion. By appropriately setting conditions, increasing multiple fields of view, and coordinating the distortion of different lenses, the relative optical distortion of the lens can be controlled within a small numerical range, thereby minimizing the distortion of the captured image. If the value exceeds the upper limit, the optical system will exhibit significant image distortion, affecting the actual viewing experience. However, if the value falls below the lower limit, barrel distortion will occur. Furthermore, to reliably obtain the effect of condition 6), it is preferable to set the value of condition 6) to 1.3%.

[0115] Condition 7) defines the focal lengths of the three cemented lenses. By appropriately setting the conditions, the chromatic aberration of the optical system across the broad spectrum is balanced, improving chromatic aberration performance. If the values ​​of the three parameters are higher than the upper limit, the first and second lenses are overcorrected and become sensitive, while the third cemented lens is undercorrected. However, if the values ​​are lower than the lower limit, the first and second cemented lenses have insufficient correction capability, the third cemented lens is overcorrected, and the lens becomes sensitive. Furthermore, to reliably obtain the effect of condition 7), it is more preferable to set the value of condition 7) to f. c1 / f = -3.3, f c2 / f = -1.7, f c3 / f = 1.4.

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

[0117] Please refer to the optical structure of Example 1. Figure 1 The specific parameters for Example 1 are shown in Table 1 below. In Example 1, the lens focal length f' = 1mm, aperture F = 1.0, field of view (FOV) = 20°, and total optical length (TTL) = 1.54mm. The conditional expressions are 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 = -0.5mm (optical system focal length scaled to f = 1mm); 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 Parameter Table

[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 Third lens -3.295 0.03 Glass 1.7 30 -0.7 5 0.532 0.12 6 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 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 Eighth lens 0.536 0.19 Low melting point glass 1.8 41 0.5 14 -1.278 0.01 15 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 shows the aspheric coefficients of the eighth lens in Example 1.

[0129] Face 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] In this embodiment, the eighth lens is an aspherical lens, meaning both its object-side and image-side surfaces are aspherical. The equation for the surface curve of an aspherical lens is as follows:

[0131]

[0132] In the formula, z: the depth of the aspherical surface (the perpendicular distance between a point on the aspherical surface at a distance y from the optical axis and the tangent plane at the vertex on the optical axis of the aspherical surface); c: the curvature of the vertex of the aspherical surface; K: the conic constant. Radial distance; r n : Normalization radius (NRADIUS); u: a m Q of order mcon coefficient (the m) th Q con coefficient); Q of order m con polynomial (the m) th Q con (polynomial).

[0133] Please see Figure 2 Example 1 shows the MTF curves. The horizontal axis represents frequency, with units of line pairs. The vertical axis represents MTF values, with no units. As can be seen from the graph, the MTF curves for each field of view are relatively concentrated and relatively straight. At 60 Lp / mm, the MTF mainly concentrates around 0.3. The imaging quality is good, meeting the requirements of the paired sensor, and the imaging effect is excellent.

[0134] Please see Figure 3 Example 1 shows the field curvature distortion diagram of the optical system. The left diagram shows the field curvature, with the horizontal axis representing the field curvature value in millimeters and the vertical axis representing the normalized field of view in infinitesimal. From the diagram, it can be clearly seen that the field curvature of this lens is within 0.1 mm. The right diagram shows the relative optical distortion, with the horizontal axis representing the percentage of relative optical distortion in % and the vertical axis representing the normalized field of view in infinitesimal. From the diagram, it can be clearly seen that the relative optical distortion of the lens is approximately 1.5%, which meets the requirements for high-precision measurement.

[0135] Please see Figure 4 The star pattern of the optical system in Example 1 shows that the lens has well-optimized star dispersion, with circular star shapes. The RMS radius of the resulting star points is 7.871 μm, which matches the sensor's requirements. The geometric radius is 48.256 μm, which meets the current requirements.

[0136] Please see Figure 5 Example 1 shows the chromatic aberration diagram of the optical system. The horizontal axis represents the chromatic aberration value in micrometers, and the vertical axis represents the normalized field of view in infinitesimal units. The vertical lines on the left and right sides represent the range of iridium radius values. From the diagram, it can be seen that the maximum chromatic aberration value of this lens in the entire field of view (434nm-1000nm) is approximately +7µm, corresponding to a wavelength of 546nm. The minimum value is -6µm, corresponding to a wavelength of 1000µm. This optical system exhibits good chromatic aberration correction, comparable to the pixel size, and high color fidelity.

[0137] Please see Figure 6 The spherical aberration diagram of the optical system in Example 1 shows that the maximum spherical aberration is around 0.12 mm. The 434 nm wavelength shifts to the right as the aperture increases, intersecting with the 1000 nm wavelength at an aperture of 0.6 mm. Other wavelengths converge and cluster together as the aperture increases.

[0138] Please see Figure 7 The relative illumination diagram of the optical system in Example 1 shows that the relative illumination of the entire field of view of the optical system is greater than 50%, the brightness of the resulting image is uniform, and there is no obvious dark corner phenomenon at the edge.

[0139] Please see Figure 8 The MTF vs Field diagram for the optical system in Example 1 shows that the meridional and sagittal rays are tightly intertwined, indicating good astigmatism correction across the entire field of view. The imaging lens provides balanced imaging in both the meridional and sagittal directions without deviation. The central field of view is superior to the full field of view, facilitating focusing and finding the optimal image plane. At 30 Lp / mm, the central MTF is greater than 0.7, and the full field of view MTF is greater than 0.4. At 60 Lp / mm, the central MTF is greater than 0.4, and the full field of view MTF is around 0.1.

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

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

[0142] 2. The system uses a wide-spectrum wavelength as its wavelength, sets wavelength weights on the sensor response curve according to different wavelengths, takes into account the defocusing of both visible and infrared wavelengths, and additionally sets up multiple structural configurations for visible and infrared wavelengths to observe the imaging quality, thus creating an optical system that meets the wavelength setting requirements.

[0143] 3. By scaling the optical system as a whole, the system focal length is increased, improving the object-side resolution. At the same time, the optical focal length is reasonably allocated, aspherical surfaces are introduced to reduce the residual spherical aberration of the system. Combined with a sensor with a resolution of around 1 million pixels, the image imaging quality is improved.

[0144] 4. By using aspherical lenses, the number of glass elements is reduced, the overall size of the lens is reduced, and the weight of the lens is lowered.

[0145] 5. By increasing multiple fields of view and coordinating the distortion of different lenses, the relative optical distortion of the lens is controlled within a small range, thereby reducing the degree of image distortion.

[0146] 6. The second and sixth lenses use glass with a negative temperature coefficient of refractive index dn / dT and employ a multi-temperature structure with no pyrolysis to ensure that the position of the imaging surface changes little and the image quality is clear within a temperature range of -40℃ to +85℃.

[0147] Example 2

[0148] For reference Figure 9 A description of an electronic device A according to Example 2 of the present invention will be given. Figure 9This is a schematic diagram of an electronic device (camera) used in a photographic optical system, based on any of the large-aperture wide-spectrum imaging lenses in Example 1.

[0149] exist Figure 9 In the figures, reference numeral A2 indicates the main body of the electronic device, and reference numeral A1 indicates any of the camera optical systems (interchangeable lenses) including the large-aperture broadband imaging lens according to Example 1. Reference numeral A3 indicates 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 (the optical image formed by the camera optical system A1) from the camera optical system A1 and performs photoelectric conversion.

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

[0151] Each example can provide electronic devices with high optical performance.

[0152] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims will be given the broadest interpretation to cover 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, the lenses are arranged in the following order: first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, and ninth lens. The first lens has positive refractive power, with a convex object side and a concave image side; The second lens has positive refractive power, and the object side is convex, as is the image side; The third lens has negative refractive power, and both the object-side and image-side surfaces are concave. The fourth lens has positive refractive power, with a concave object side and a convex image side; The fifth lens has negative refractive power, and both the object-side and image-side surfaces are concave. The sixth lens has positive refractive power, and the object side is convex, as is the image side; The seventh lens has negative refractive power, and both the object-side and image-side surfaces are concave. The eighth lens has positive refractive power, and the object side and the image side are both convex. The ninth lens has negative refractive power, and both the object-side and image-side surfaces are concave. The image-side surface of the second lens and the object-side surface of the third lens are cemented together to form a first cemented lens; The image-side surface of the fourth lens and the object-side surface of the fifth lens are cemented together to form a second cemented lens; The image-side surface of the sixth lens and the object-side surface of the seventh lens are cemented together to form a third cemented lens; The lens satisfies the following conditions: |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; |f9 / f|=0.6; In the formula, f1, f2, f3, f4, f5, f6, f7, f8, f9, and f 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, the ninth lens, and the focal length of the lens, respectively.

2. The large-aperture broadband imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: Fno=1.0; f / y=5.6; In the formula, Fno is the F-Number of the lens, and y is the half-image height of the imaging plane of the lens.

3. The large-aperture broadband imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: WD = 0.8 ~ ∞; △FB = 2.6; In the formula, WD is the working distance of the lens, and △FB is the change in the back clip of the lens.

4. The large-aperture broadband imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: TTL = 1.54; D1 / f = 0.95; In the formula, TTL is the total optical length of the imaging lens, and D1 is the effective aperture of the first element of the optical system.

5. A large-aperture, wide-spectrum imaging lens as described in claim 1, characterized in that, The eighth lens is a low-melting-point aspherical lens, and the lens satisfies the following condition: f8=-0.5mm; Nd8=1.8; Vd8=41; In the formula, f8 is the focal length of the eighth lens, Nd8 is the refractive index of the eighth lens, and Vd8 is the Abbe coefficient of the eighth lens.

6. A large-aperture broadband imaging lens as described in claim 1, characterized in that, Both the second and sixth lenses are made of glass material with a negative temperature coefficient of refractive index dn / dT.

7. A large-aperture, wide-spectrum imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: Optical Distortion = 1.3%; In the formula, Optical Distortion is the relative optical distortion of the lens.

8. A large-aperture, wide-spectrum imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: f c1 / f= -3.3;f c2 / f= -1.7;f c3 / f = 1.4; In the formula, f c1 f c2 f c3 These are the focal lengths of the first cemented lens, the second cemented lens, and the third cemented lens, respectively.

9. An electronic device, characterized in that, A large-aperture broadband imaging lens according to any one of claims 1-8; and An image sensor is configured to receive images formed by the large-aperture broadband imaging lens.

Images