An ultra-close-range imaging lens and electronic device

Abstract

This invention discloses an ultra-close-range imaging lens and electronic device. The lens 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, a ninth lens, and a tenth lens. The first lens has positive refractive power and has an object-side surface facing the object side and an image-side surface facing the object side; the object-side surface is planar, and the image-side surface is convex. The second lens has negative refractive power and has an object-side surface facing the object side and an image-side surface facing the object side; the object-side surface is convex, and the image-side surface is concave. The third lens has negative refractive power and has an object-side surface facing the image side and an image-side surface facing the object side; the object-side surface is convex, and the image-side surface is concave, etc. The lens of this invention has a minimum working distance of 18.6 mm and can be adapted to a target surface resolution of 12 MP (1 / 2.3 inch); a working focal ratio of F#4.0, a numerical aperture NA of 0.124, and a focal length of f=7 mm, resulting in a wider depth of field and a wider range of objects viewed.

Description

Technical Field

[0001] This invention relates to the field of near-object distance imaging lens technology, and more particularly to an ultra-near-object distance imaging lens and electronic device. Background Technology

[0002] Ultra-close-range industrial lenses are lenses specifically designed for close-range imaging and inspection in industrial applications. These lenses are typically used in scenarios requiring high magnification and extremely high detail resolution, such as electronic component inspection, material surface inspection, and precision assembly. Existing ultra-close-range industrial lenses have at least one of the following drawbacks:

[0003] 1) Lenses are generally designed for infinity, and their image quality is poor when used at close distances;

[0004] 2) Generally, close-range lenses have a large focal length. When the light is constant, a large focal length results in a small depth of field and severe background blur.

[0005] 3) Lens distortion is generally not specially controlled; optical distortion greater than 5% results in large image edge deformation.

[0006] 4) Lenses are prone to focus loss at high and low temperatures, and image quality is greatly affected by temperature. Summary of the Invention

[0007] In view of this, the object of the present invention is to provide an ultra-close-range imaging lens and electronic device. This lens can at least solve one of the technical shortcomings mentioned in the background art.

[0008] According to one aspect of the present invention, an ultra-close object distance 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, a ninth lens, and a tenth lens.

[0009] The first lens has positive diopter and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is a plane and the image-side surface is a convex surface.

[0010] The second lens has negative refractive power and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is concave.

[0011] The third lens has negative refractive power and has an object-side surface facing the image side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is concave.

[0012] The fourth lens has positive diopter and has an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface is convex and the image-side surface is convex.

[0013] The fifth lens has negative refractive power and has an object-side surface facing the object side and an object-side surface facing the object side. The object-side surface is concave and the image-side surface is convex.

[0014] The sixth lens has positive diopter and has an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface is convex and the image-side surface is convex.

[0015] The seventh lens has positive refractive power and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is convex.

[0016] The eighth lens has positive diopter and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is convex.

[0017] The ninth lens has negative refractive power and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is concave.

[0018] The tenth lens has positive diopter and has an object-side surface facing the object and an image-side surface facing the object. The object-side surface is convex and the image-side surface is flat.

[0019] In the above technical solution, the lens has a minimum working distance of 18.6mm and can be adapted to a target surface resolution of 12MP (1 / 2.3 inch). Its working focal ratio is F#4.0, numerical aperture NA=0.124, and focal length f=7mm, resulting in a wider depth of field and a broader range of objects viewed. The absolute optical distortion of this solution is less than 2%, meeting the characteristics of a distortion-free lens and making it suitable for use in inspection systems.

[0020] In some embodiments, the lens satisfies the following condition:

[0021] D R2 / R2≤1.60; e>1mm

[0022] In the formula, D R2 R2 is the aperture of the second surface of the first lens, R2 is the radius of curvature of the second surface of the first lens, and e is the thickness of the lens edge.

[0023] In the above technical solution, the lens edge thickness is >1.5mm, the front end of the lens can be expanded to accommodate a waterproof sealing ring to meet the lens's waterproof requirements, the lens shape has already accommodated sufficient lens edge thickness, and D R2 / R2≤1.4 improves the reliability and dependability of the system, which can meet the requirements of lens reliability experiments.

[0024] In some embodiments, both the second lens and the third lens are crescent-shaped.

[0025] In the above technical solution, the second and third lenses are crescent-shaped, which can achieve smaller system distortion, optimize aberrations, and improve image quality.

[0026] In some embodiments, the lens satisfies the following condition:

[0027] -20 <f2<-8;-20<f3<-8

[0028] In the formula, f2 is the focal length of the second lens; f3 is the focal length of the third lens.

[0029] In the above technical solution, appropriately setting the focal lengths of the second and third lenses can optimize image quality and improve system performance.

[0030] In some embodiments, the lens satisfies the following condition:

[0031] 8 <f4<15;Nd4>1.75

[0032] In the formula, f4 is the focal length of the fourth lens, and Nd4 is the refractive index of the fourth lens.

[0033] In the above technical solution, a high refractive index material is used for the fourth lens, with Nd4 > 1.75, to optimize image quality and achieve high resolution.

[0034] In some embodiments, the fifth lens and the sixth lens are cemented together to form a first cemented lens group, and the lens satisfies the following condition:

[0035] Vd5≤29.5; Vd6≥58; Vd6-Vd5>29

[0036] In the formula, Vd5 is the dispersion coefficient of the fifth lens, and Vd6 is the dispersion coefficient of the sixth lens.

[0037] In the above technical solution, the cemented lens uses a combination of high and low dispersion materials to effectively control chromatic aberration, reduce distortion, optimize image quality, and improve system performance.

[0038] In some embodiments, the ninth lens and the tenth lens are cemented together to form a second cemented lens group, wherein the tenth lens is made of fluorophosphate crown glass, and the lens satisfies the following condition:

[0039] Vd9≤54;Vd 10 ≥81; Vd 10 -Vd9>27

[0040] In the formula, Vd9 is the dispersion coefficient of the ninth lens, and Vd 10 The dispersion coefficient of the tenth lens is given.

[0041] In the above technical solution, the cemented lens combines high and low dispersion materials to effectively control chromatic aberration, reduce distortion, optimize image quality, and improve system performance. Meanwhile, the tenth lens uses fluorophosphate crown glass, characterized by dn / dT < -6*10E-6 within a temperature range of -40℃ to 80℃. The smaller the dn / dT of a positive focal length lens, the more effectively it balances temperature drift, which is beneficial for achieving passive calorimetry in optical lenses.

[0042] In some embodiments, the lens satisfies the following condition:

[0043] TTL / BFL≥4

[0044] In the formula, TTL is the total length of the lens; BFL is the optical back focal length of the lens.

[0045] In the above technical solution, appropriate back coke helps to reduce the temperature drift caused by mechanical parts, which can reduce the temperature drift of the entire system and is conducive to athermization.

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

[0047] D 10 / IMH > 0.9

[0048] In the formula, D 10 The effective aperture of the tenth lens is given, and IMH is the target surface size of the lens.

[0049] In the above technical solution, the above settings enable the overall light to transition to the image plane relatively smoothly, reduce CRA, have strong tolerance and manufacturability, and are more suitable for mass production.

[0050] According to another aspect of the present invention, an electronic device is provided, comprising the aforementioned ultra-close-range imaging lens; and

[0051] An image sensor is configured to receive images formed by the ultra-close-range imaging lens.

[0052] In the above technical solution, the advantage of this electronic device relies on the ultra-close object distance imaging lens, which will not be elaborated here. Attached Figure Description

[0053] 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.

[0054] Figure 1This is a schematic diagram of the structure of an example 1 of an ultra-close object distance imaging lens according to the present invention;

[0055] Figure 2 This is an MTF curve of an example 1 of an ultra-close object distance imaging lens of the present invention;

[0056] Figure 3 This is a field curvature and distortion curve diagram of an example 1 of an ultra-close object distance imaging lens of the present invention;

[0057] Figure 4 This is a chromatic aberration diagram of an example 1 of an ultra-close object distance imaging lens of the present invention;

[0058] Figure 5 This is an on-axis chromatic aberration diagram of an example 1 of an ultra-close object distance imaging lens of the present invention;

[0059] Figure 6 This is a dot diagram of an example 1 of an ultra-close object distance imaging lens according to the present invention;

[0060] Figure 7 This is a relative illumination diagram of an example 1 of an ultra-close object distance imaging lens of the present invention;

[0061] Figure 8 This is a schematic diagram of the structure of an example 2 of an ultra-close object distance imaging lens according to the present invention;

[0062] Figure 9 This is an MTF curve of an example 2 of an ultra-close object distance imaging lens of the present invention;

[0063] Figure 10 This is a field curvature and distortion curve diagram of an example 2 of an ultra-close object distance imaging lens of the present invention;

[0064] Figure 11 This is a chromatic aberration diagram of an example 2 of an ultra-close object distance imaging lens of the present invention;

[0065] Figure 12 This is an on-axis chromatic aberration diagram of an example 2 of an ultra-close object distance imaging lens of the present invention;

[0066] Figure 13 This is a dot diagram of an example 2 of an ultra-close object distance imaging lens according to the present invention;

[0067] Figure 14 This is a relative illumination diagram of an example 2 of an ultra-close object distance imaging lens of the present invention;

[0068] Figure 15 This is a schematic diagram of the structure of an example 3 of an ultra-close object distance imaging lens according to the present invention;

[0069] Figure 16 This is an MTF curve of an example 3 of an ultra-close object distance imaging lens of the present invention;

[0070] Figure 17 This is a field curvature and distortion curve diagram of an example 3 of an ultra-close object distance imaging lens of the present invention;

[0071] Figure 18 This is a chromatic aberration diagram of an example 3 of an ultra-close object distance imaging lens of the present invention;

[0072] Figure 19 This is an on-axis chromatic aberration diagram of an example 3 of an ultra-close object distance imaging lens of the present invention;

[0073] Figure 20 This is a dot diagram of Example 3 of an ultra-close object distance imaging lens of the present invention;

[0074] Figure 21 This is a relative illumination diagram of an example 3 of an ultra-close object distance imaging lens of the present invention;

[0075] Figure 22 This is a schematic diagram of the structure of an electronic device example 4 of the present invention. Detailed Implementation

[0076] 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.

[0077] The purpose of this invention is to provide an ultra-close-range 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.

[0078] Figure 1 , Figure 8 , Figure 15 These are cross-sectional views of ultra-close-range imaging lenses (optical systems) according to Examples 1 to 3. The ultra-close-range imaging lenses according to each example are used in imaging devices including 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, G1 represents the filter, G2 represents the protective lens, Ci represents the i-th group of cemented lenses, ST represents the aperture stop (fixed aperture stop or visible aperture stop), and IMA represents the image plane. When the ultra-close-range imaging lenses 1 to 3 according to each example are used in the imaging optical system of a digital video camera or digital still camera, a solid-state imaging element (photoelectric conversion element), such as a CMOS image sensor or a CCD image sensor, is arranged on the image plane IMA.

[0079] According to the various examples, the ultra-close object distance imaging lenses, in order from the object side to the image side, are: first lens L1, second lens L2, third lens L3, aperture ST, fourth lens L4, fifth lens L5, sixth lens L6, seventh lens L7, eighth lens L8, ninth lens L9, and tenth lens L10.

[0080] The first lens L1 has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is planar, and the image-side surface is convex. The second lens L2 has negative refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is convex, and the image-side surface is concave. The third lens L3 has negative refractive power, and has an object-side surface facing the image side and an image-side surface facing the object side. The object-side surface is convex, and the image-side surface is concave. The fourth lens L4 has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side. Both the object-side surface and the image-side surface are convex. The fifth lens L5 has negative refractive power, and has an object-side surface facing the object side and an object-side surface facing the object side. The object-side surface is concave, and the image-side surface is convex. The sixth lens L6 has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface and the image-side surface are both convex. The seventh lens L7 has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface and the image-side surface are both convex. The eighth lens L8 has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface and the image-side surface are both convex. The ninth lens L9 has negative refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is both convex and the image-side surface is both concave. The tenth lens L10 has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is both convex and the image-side surface is flat.

[0081] The fifth lens L5 and the sixth lens L6 are cemented together to form the first cemented lens group C1. The ninth lens L9 and the tenth lens L10 are cemented together to form the second cemented lens group C2. The tenth lens is made of fluorophosphate crown glass. The tenth lens, made of fluorophosphate crown glass, is characterized by dn / dT < -6*10E-6 in the temperature range of -40℃ to 80℃. The smaller the dn / dT of a positive focal length lens, the more effectively it balances temperature drift, which is beneficial for achieving passive heatless optical lens manufacturing. The object plane of the first lens and the image plane of the tenth lens are both planar. These features improve the front and rear support of the lens, making the overall structure more stable, improving manufacturability, and increasing production yield.

[0082] The ultra-close-range imaging lenses in each example can satisfy at least one of the following settings 1) to 8):

[0083] 1)D R2 / R2≤1.60; e>1mm;

[0084] 2) Both the second lens and the third lens are crescent-shaped;

[0085] 3)-20 <f2<-8;-20<f3<-8;

[0086] 4)8 <f4<15;Nd4>1.75;

[0087] 5)Vd5≤29.5; Vd6≥58; Vd6-Vd5>29;

[0088] 6) Vd9≤54; Vd 10 ≥81; Vd 10 -Vd9>27;

[0089] 7) TTL / BFL ≥ 4;

[0090] 8)D 10 / IMH > 0.9;

[0091] In the above conditional expression, D R2 R2 is the aperture of the second surface of the first lens, R2 is the radius of curvature of the second surface of the first lens, e is the edge thickness of the lens; f2 is the focal length of the second lens; f3 is the focal length of the third lens; f4 is the focal length of the fourth lens; Nd4 is the refractive index of the fourth lens; Vd5 is the dispersion coefficient of the fifth lens; Vd6 is the dispersion coefficient of the sixth lens; Vd9 is the dispersion coefficient of the ninth lens; Vd... 10 The tenth lens has a chromatic aberration coefficient; TTL is the total length of the lens; BFL is the optical back focal length of the lens; D 10 The effective aperture of the tenth lens is given by , and IMH is the target surface size of the lens.

[0092] Condition 1) defines the ratio of the aperture of the second surface of the first lens to the radius of curvature of the second surface of the first lens, and the lens edge thickness. By appropriately setting the conditions, the first lens is a positive focal length lens and satisfies the requirement that the lens edge thickness > 1.5mm. The front end of the lens can be expanded to fit a waterproof sealing ring to meet the lens waterproof requirements. The lens shape has sufficient margin for lens edge thickness, and D R2 A radius of curvature (R²) ≤ 1.4 improves the system's reliability and ensures it meets lens reliability testing requirements. If the ratio of the aperture of the second surface of the first lens to the radius of curvature of the second surface of the first lens exceeds the upper limit, the yield of the cold-processed and ground lens will be low and will not meet mass production requirements. If the lens edge thickness is below the lower limit, the reliability requirements for falling ball and stone fragmentation lenses will not be met.

[0093] Condition 2) defines the lens types of the second lens and the third lens. By setting appropriate conditions, the second lens and the third lens are crescent-shaped, which can achieve smaller distortion of the system, optimize aberrations, and improve image quality.

[0094] Condition 3) defines the focal lengths of the second and third lenses. By appropriately setting the conditions, image quality can be optimized and system performance improved. If the value is higher than the upper limit, a single lens will bear more optical power, resulting in a larger light refraction angle on the corresponding surface and increasing the tolerance sensitivity of the lens. If the value is lower than the lower limit, the miniaturization requirements of the optical system cannot be met. Furthermore, to reliably obtain the effect of condition 3), it is more preferable to set the values ​​of condition 3) to f2 = -11.93 mm and f3 = -14.41 mm.

[0095] Condition 4) defines the parameters of the fourth lens. By appropriately setting the conditions, image quality is optimized to achieve high resolution. If the focal length value is higher than the upper limit, it is not conducive to achieving high resolution. If the focal length value is lower than the lower limit, the positive and negative distribution of optical power of the lens cannot be reasonably controlled, increasing the difficulty of balancing lens aberrations. If the refractive index is lower than the lower limit, the center thickness of the lens becomes thicker, which is not conducive to the requirement of lens lightweight. In addition, in order to reliably obtain the effect of condition 3), it is more preferable to set the value of condition 3) to f4 = 12.61mm and Nd4 = 1.76.

[0096] Condition 5) defines the Abbe numbers of the fifth and sixth lenses. By appropriately setting the conditions, chromatic aberration can be effectively controlled, distortion reduced, image quality optimized, and system performance improved. If the dispersion coefficient of the fifth lens is higher than the upper limit, it does not have anomalous dispersion characteristics. If the dispersion coefficient of the sixth lens is lower than the lower limit, partial dispersion correction cannot be effectively achieved, increasing the difficulty of correcting partial dispersion of blue and violet light. If the difference between the two is lower than the lower limit, second-order chromatic aberration cannot be controlled or eliminated, and image quality cannot be effectively improved. Furthermore, to reliably obtain the effect of condition 5), it is more preferable to set the values ​​of condition 5) to Vd5 = 29.5, Vd6 = 58.6, and Vd6 - Vd5 = 29.1.

[0097] Condition 6) defines the Abbe numbers of the ninth and tenth lenses. By appropriately setting the conditions, chromatic aberration can be effectively controlled, distortion reduced, image quality optimized, and system performance improved. If the dispersion coefficient of the ninth lens is higher than the upper limit, it is not conducive to controlling lens chromatic aberration. If the dispersion coefficient of the tenth lens is lower than the lower limit, partial chromatic aberration correction cannot be effectively achieved, increasing the difficulty of correcting blue-violet light partial chromatic aberration. If the difference between the two is lower than the lower limit, second-order chromatic aberration cannot be controlled and eliminated, and image quality cannot be effectively improved. Furthermore, to reliably obtain the effect of condition 6), it is more preferable to set the value of condition 6) to Vd9 = 53.4, Vd 10 =81.6, Vd 10 -Vd9 = 28.2.

[0098] Condition 7) defines the ratio of the total lens length to the optical back focal length. By setting the condition appropriately, it is beneficial to reduce the temperature drift caused by mechanical components, thereby reducing the temperature drift of the entire system and promoting heatless operation. If the ratio is lower than the lower limit, the total optical length will increase, which is not conducive to controlling the lens length. Furthermore, in order to reliably obtain the effect of condition 7), it is more preferable to set the value of condition 7) to TTL / BFL = 4.3.

[0099] Condition 8) defines the ratio of the effective aperture of the tenth lens to the target surface size. By appropriately setting the condition, the overall light can transition relatively smoothly to the image plane, reducing CRA (Collateral Radiation Amplitude), improving tolerance and manufacturability, and enhancing mass production feasibility. If the ratio is below the lower limit, the maximum principal ray incident angle of the sensor will increase, making it incompatible with mainstream sensors. Furthermore, to reliably obtain the effect of condition 8), it is preferable to set the value of condition 8) to D. 10 / IMH=1.2.

[0100] A detailed description of ultra-close-range imaging lenses based on various examples will now be given.

[0101] Please refer to the optical structure of Example 1. Figure 1 The specific parameters of Example 1 are shown in Table 1 below. The optical system has a focal length f = 6.92 mm, numerical aperture NA = 0.124, working focal ratio F# = 4, field of view FOV = 57°, target size IMH = 7.81 mm, and total optical length TTL = 35.58 mm. The conditions are as follows:

[0102] 1)D R2 / R2≤1.45; e>1.5mm;

[0103] 2) Both the second lens and the third lens are crescent-shaped;

[0104] 3)f2=-11.93; f3=-14.41;

[0105] 4) f4 = 12.61; Nd4 = 1.76;

[0106] 5) Vd5=29.5; Vd6=58.6; Vd6-Vd5=29.1;

[0107] 6) Vd9 = 53.4; Vd 10 =81.6; Vd 10 -Vd9 = 28.2;

[0108] 7) TTL / BFL = 4.3

[0109] 8)D 10 / IMH=1.2

[0110] Table 1 Example 1 Parameter Table

[0111] Face number type radius of curvature thickness Material Refractive index Abbe coefficient lens focal length 0 Infinity 18.600 1 First lens Infinity 3.500 Glass 1.52 64.2 56.32 2 -29.200 0.100 3 Second lens 8.511 3.320 Glass 1.73 51.5 -11.93 4 3.607 1.185 5 The third lens 62.566 0.700 Glass 1.52 64.2 -14.41 6 6.647 0.220 7 Fourth lens 11.737 5.140 Glass 1.76 26.2 12.61 8 -44.832 0.030 9 aperture Infinity 1.203 10 Fifth lens -4.922 0.780 Glass 1.72 29.5 -5.32 11 Sixth lens 18.795 1.620 Glass 1.61 58.6 6.87 12 -5.272 0.498 13 Seventh Lens 50.510 1.820 Glass 1.5 81.6 17.36 14 -10.317 0.596 15 Eighth lens 30.688 1.360 Glass 1.76 52.3 18.32 16 -24.888 1.404 17 Ninth Lens 14.061 0.920 Glass 1.69 53.4 -14.67 18 Tenth Lens 5.757 2.930 Glass 1.5 81.6 11.55 19 Infinity 0.750 20 Filter Infinity 0.300 Glass 1.52 64.2 21 Infinity 6.208 22 protective sheet Infinity 0.500 Glass 1.52 64.2 23 Infinity 0.500 24 Imaging surface Infinity -

[0112] Please see Figure 2 Example 1 shows the MTF curves, which represent the diffraction modulation transfer function (MTF) data for all fields of view. The larger the area enclosed by the MTF curve and the coordinate axes, the more information the optical system transmits, the better the imaging quality of the optical system, and the clearer the image. From the graph, we can see that the horizontal axis is 125 lp / mm, and the vertical axis values ​​of all curves are >0.3.

[0113] Please see Figure 3 Example 1 shows the field curvature and distortion curves. In the distortion curve, the field of view is the vertical axis and the distortion value is the horizontal axis. It can be seen from the figure that the F-Tan (Theta) distortion is <2% in the entire field of view.

[0114] Please see Figure 4 In Example 1, the horizontal axis of the vertical axis color difference diagram represents the color difference value of different wavelengths, and the vertical axis represents the field of view size. It can be seen from the diagram that the wavelength ranges from 435nm to 650nm. The 435nm wavelength (blue line) deviates from the main wavelength 555nm (red line) by a color difference value of less than 8um, which makes the system have high color reproduction.

[0115] Please see Figure 5 The on-axis chromatic aberration diagram in Example 1, also known as positional chromatic aberration and spherical aberration, shows the horizontal axis representing the deviation from the image plane and the vertical axis representing the normalized maximum entrance pupil radius. The diagram shows that the chromatic aberration curves intersect at wavelengths from 435nm to 650nm, and their common focal point deviates relatively little from the red of the principal ray d-line, indicating that the optical system has excellent image quality and good apochromatic aberration.

[0116] Please see Figure 6 The dot plot in Example 1 reflects the imaging of point objects; the denser the dots, the better the optical imaging quality.

[0117] Please see Figure 7 Example 1 shows the relative illuminance curve, with the horizontal axis representing different fields of view and the vertical axis representing the relative illuminance magnitude. As can be seen from the figure, the curve is relatively flat, and the RI is greater than 60% at the edge of the field of view, indicating that the system has high relative illuminance, high brightness from the center to the edge, and uniformity.

[0118] Please refer to the optical structure of Example 2. Figure 8 The specific parameters of Example 2 are shown in Table 2 below. The optical system has a focal length f = 7.2 mm, numerical aperture NA = 0.124, working focal ratio F# = 4, field of view FOV = 47°, target size IMH = 6.67 mm, and total optical length TTL = 35.94 mm. The conditions are as follows:

[0119] 1)D R2 / R2≤1.55; e>1.0mm;

[0120] 2) Both the second lens and the third lens are crescent-shaped;

[0121] 3)f2=-11.93; f3=-14.41;

[0122] 4) f4 = 12.61; Nd4 = 1.76;

[0123] 5) Vd5=29.5; Vd6=58.6; Vd6-Vd5=29.1;

[0124] 6) Vd9 = 53.4; Vd 10 =81.6; Vd 10 -Vd9 = 28.2;

[0125] 7) TTL / BFL = 4.55

[0126] 8)D 10 / IMH=1.15

[0127] Table 2 Example 2 Parameter Table

[0128] Face number type radius of curvature thickness Material Refractive index Abbe coefficient lens focal length 0 Infinity 18.600 1 First lens 260.310 3.500 Glass 1.52 64.2 51.72 2 -29.758 0.667 3 Second lens 8.511 3.320 Glass 1.73 51.5 -11.93 4 3.607 1.160 5 The third lens 62.566 0.700 Glass 1.52 64.2 -14.41 6 6.647 0.243 7 Fourth lens 11.737 5.140 Glass 1.76 26.2 12.61 8 -44.832 0.114 9 aperture Infinity 1.254 10 Fifth lens -4.922 0.780 Glass 1.72 29.5 -5.32 11 Sixth lens 18.795 1.620 Glass 1.61 58.6 6.87 12 -5.272 0.106 13 Seventh Lens 50.510 1.820 Glass 1.5 81.6 17.36 14 -10.317 0.581 15 Eighth lens 30.688 1.360 Glass 1.76 52.3 18.32 16 -24.888 1.801 17 Ninth Lens 14.061 0.920 Glass 1.69 53.4 -14.67 18 Tenth Lens 5.757 2.930 Glass 1.5 81.6 11.55 19 Infinity 0.750 20 Filter Infinity 0.300 Glass 1.52 64.2 21 Infinity 5.874 22 protective sheet Infinity 0.500 Glass 1.52 64.2 23 Infinity 0.500 24 Imaging surface Infinity -

[0129] Please see Figure 9 Example 2 shows the MTF curves, which represent the diffraction modulation transfer function (MTF) data for all fields of view. The larger the area enclosed by the MTF curve and the coordinate axes, the more information the optical system transmits, the better the imaging quality of the optical system, and the clearer the image. From the graph, we can see that the horizontal axis is 125 lp / mm, and the vertical axis values ​​of all curves are >0.3.

[0130] Please see Figure 10 Example 2 shows the field curvature and distortion curves. In the distortion curve, the field of view is the vertical axis and the distortion value is the horizontal axis. It can be seen from the figure that the F-Tan (Theta) distortion is <1.6% in the entire field of view.

[0131] Please see Figure 11 In Example 2, the horizontal axis of the vertical axis color difference plot represents the color difference value of different wavelengths, and the vertical axis represents the field of view size. As can be seen from the figure, the wavelength ranges from 435nm to 650nm. The 435nm wavelength (blue line) deviates from the main wavelength 555nm (red line) by a color difference value of less than 9um, which makes the system's color reproduction slightly worse than that of Example 1.

[0132] Please see Figure 12The on-axis chromatic aberration diagram in Example 2, also known as positional chromatic aberration and spherical aberration, shows the horizontal axis representing the deviation from the image plane and the vertical axis representing the normalized maximum entrance pupil radius. The diagram shows that the chromatic aberration curves intersect at wavelengths from 435nm to 650nm, and their common focal point deviates relatively little from the red of the principal ray d-line, indicating that the optical system has excellent image quality, although its apochromatic aberration is slightly worse than in Example 1.

[0133] Please see Figure 13 The dot plot in Example 2 reflects the imaging of point objects; the denser the dots, the better the optical imaging quality.

[0134] Please see Figure 14 Example 2 shows the relative illuminance curve, with the horizontal axis representing different fields of view and the vertical axis representing the relative illuminance magnitude. As can be seen from the figure, the curve is relatively flat, and the RI is greater than 70% at the edge of the field of view, indicating that the system has high relative illuminance, high brightness from the center to the edge, and uniformity.

[0135] Please refer to the optical structure of Example 3. Figure 15 The specific parameters of Example 3 are shown in Table 3 below. The optical system has a focal length f = 6.96 mm, numerical aperture NA = 0.124, working focal ratio F# = 4, field of view FOV = 56.46°, target size IMH = 7.81 mm, and total optical length TTL = 34.66 mm. The conditions are as follows:

[0136] The condition is as follows:

[0137] 1)D R2 / R2≤1.6; e>1.0mm;

[0138] 2) Both the second lens and the third lens are crescent-shaped;

[0139] 3)f2=-11.93; f3=-14.41;

[0140] 4) f4 = 12.61; Nd4 = 1.76;

[0141] 5) Vd5=29.5; Vd6=58.6; Vd6-Vd5=29.1;

[0142] 6) Vd9 = 53.4; Vd 10 =81.6; Vd 10 -Vd9 = 28.2;

[0143] 7) TTL / BFL = 4

[0144] 8)D 10 / IMH=1.15

[0145] Table 3 Example 3 Parameter Table

[0146]

[0147]

[0148] Please see Figure 16 Example 3 shows the MTF curves, which represent the diffraction modulation transfer function (MTF) data for all fields of view. The larger the area enclosed by the MTF curve and the coordinate axes, the more information the optical system transmits, the better the imaging quality of the optical system, and the clearer the image. From the graph, we can see that the horizontal axis is 125 lp / mm, and the vertical axis values ​​of all curves are >0.4.

[0149] Please see Figure 17 Example 3 shows the field curvature and distortion curves. In the distortion curve, the field of view is the vertical axis and the distortion value is the horizontal axis. It can be seen from the figure that the F-Tan (Theta) distortion is <1.5% across the entire field of view.

[0150] Please see Figure 18 In Example 2, the horizontal axis of the vertical axis color difference diagram represents the color difference value of different wavelengths, and the vertical axis represents the field of view size. As can be seen from the diagram, the wavelength ranges from 435nm to 650nm. The 435nm wavelength (blue line) deviates from the main wavelength of 555nm (red line) by less than 10um in color difference, which makes the system's color reproduction slightly worse than that of Example 1.

[0151] Please see Figure 19 The on-axis chromatic aberration diagram in Example 3, also known as positional chromatic aberration and spherical aberration, shows the horizontal axis representing the deviation from the image plane and the vertical axis representing the normalized maximum entrance pupil radius. The diagram shows that the chromatic aberration curves intersect at wavelengths from 435nm to 650nm, and their common focal point deviates relatively little from the red of the principal ray d-line, indicating that the optical system has excellent image quality, although its apochromatic aberration is slightly worse than in Example 1.

[0152] Please see Figure 20 The dot plot in Example 3 reflects the imaging of point objects; the denser the dots, the better the optical imaging quality.

[0153] Please see Figure 21 Example 3 shows the relative illuminance curve, with the horizontal axis representing different fields of view and the vertical axis representing the relative illuminance magnitude. As can be seen from the figure, the curve is relatively flat, and the RI is greater than 68% at the edge of the field of view, indicating that the system has high relative illuminance, high brightness from the center to the edge, and uniformity.

[0154] Based on Examples 1 to 3, this case has the following advantages:

[0155] 1. The closest working distance of the lens in this solution is 18.6mm, and it can be adapted to a target surface resolution of 12MP with a maximum size of 1 / 2.3 inch.

[0156] 2. The lens in this design has a working focal ratio of F#4.0, a numerical aperture NA of 0.124, and a focal length of f=7mm, which makes the lens have a wider depth of field and a wider range of objects to be viewed.

[0157] 3. The absolute value of optical distortion in this solution is less than 2%, which meets the characteristics of a distortion-free lens and is suitable for use in inspection systems.

[0158] 4. The lens in this solution meets the temperature drift requirement from -40℃ to 85℃, and the image clarity is minimally affected by temperature.

[0159] Example 4

[0160] For reference Figure 22 A description of an electronic device A according to Example 4 of the present invention will be given. Figure 22 This is a schematic diagram of an electronic device (camera) used in a photographic optical system, based on any of the ultra-close-range imaging lenses in Examples 1 to 3.

[0161] exist Figure 22 In the figures, reference numeral A2 indicates the main body of the electronic device, and reference numeral A1 indicates any of the imaging optical systems (interchangeable lenses) including the ultra-close-range imaging lenses according to Examples 1 to 3. 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 imaging optical system A1) from the imaging optical system A1 and performs photoelectric conversion.

[0162] By using an ultra-close-range imaging lens according to any one of Examples 1 to 3 in an electronic device such as a digital still camera, an electronic device with high optical performance can be obtained.

[0163] Each example can provide electronic devices with high optical performance.

[0164] 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 super close-range 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, ninth lens, and tenth lens. The first lens has positive diopter and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is a plane and the image-side surface is a convex surface. The second lens has negative refractive power and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is concave. The third lens has negative refractive power and has an object-side surface facing the image side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is concave. The fourth lens has positive diopter and has an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface is convex and the image-side surface is convex. The fifth lens has negative refractive power and has an object-side surface facing the object side and an object-side surface facing the object side. The object-side surface is concave and the image-side surface is convex. The sixth lens has positive diopter and has an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface is convex and the image-side surface is convex. The seventh lens has positive refractive power and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is convex. The eighth lens has positive diopter and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is convex. The ninth lens has negative refractive power and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is concave. The tenth lens has positive diopter and has an object-side surface facing the object side and an image-side surface facing the object side. The object-side surface is convex and the image-side surface is flat. The lens satisfies the following condition: D R2 / R2≤1.60;e>1mm In the formula, D R2 R2 is the aperture of the second surface of the first lens, R2 is the radius of curvature of the second surface of the first lens, and e is the thickness of the lens edge; Both the second lens and the third lens are crescent-shaped.

2. The ultra-close-range imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: -20 <f2<-8;-20<f3<-8 In the formula, f2 is the focal length of the second lens; f3 is the focal length of the third lens.

3. The ultra-close-range imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: 8 <f4<15;Nd4>1.75 In the formula, f4 is the focal length of the fourth lens, and Nd4 is the refractive index of the fourth lens.

4. The ultra-close-range imaging lens as described in claim 1, characterized in that, The fifth lens and the sixth lens are cemented together to form a first cemented lens group, and the lens satisfies the following condition: Vd5≤29.5; Vd6≥58; Vd6-Vd5>29 In the formula, Vd5 is the dispersion coefficient of the fifth lens, and Vd6 is the dispersion coefficient of the sixth lens.

5. The ultra-close-range imaging lens as described in claim 1, characterized in that, The ninth lens and the tenth lens are cemented together to form a second cemented lens group, wherein the tenth lens is made of fluorophosphate crown glass, and the lens satisfies the following condition: Vd9≤54;Vd 10 ≥81;Vd 10 -Vd9>27 In the formula, Vd9 is the dispersion coefficient of the ninth lens, and Vd 10 The dispersion coefficient of the tenth lens is given.

6. The ultra-close-range imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: TTL / BFL≥4 In the formula, TTL is the total length of the lens; BFL is the optical back focal length of the lens.

7. The ultra-close-range imaging lens as described in claim 1, characterized in that, The lens satisfies the following condition: D 10 / IMH>0.9 In the formula, D 10 The effective aperture of the tenth lens is given by , and IMH is the target surface size of the lens.

8. An electronic device, characterized in that, An ultra-close-range imaging lens according to any one of claims 1-7; and An image sensor is configured to receive images formed by the ultra-close-range imaging lens.

Images