Ultra-short object distance imaging lens and electronic equipment

Abstract

The invention discloses an ultra-short object distance 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, a ninth lens and a tenth lens from an object side to an image side. The first lens has positive diopter and is provided with 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 diopter and is provided with an object side surface facing the object side and an image side surface facing the object side, the object side surface is a convex surface, and the image side surface is a concave surface; the third lens has negative diopter and is provided with an object side surface facing the image side and an image side surface facing the object side, the object side surface is a convex surface, and the image side surface is a concave surface; according to the invention, the nearest working distance of the lens can reach 18.6 mm, and the maximum target surface resolution of 1 / 2.3 inch can be adapted to 12MP; the working coke ratio F # is 4.0, and the numerical aperture NA is 0.124; and the focal length f is 7mm, so that the lens has a wider depth of field and a wider object watching range.

Description

Technical Field

[0001] The present invention relates to the technical field of close object distance imaging lenses, and in particular to an ultra-close object distance imaging lens and electronic equipment. Background Art

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

[0003] 1) Generally, lenses are designed for infinity, and the image quality is poor when used at close object distances;

[0004] 2) Generally, the focal length of close-object lenses is large. When the light transmission is constant, the focal length is large and the depth of field is small, and the background is severely blurred;

[0005] 3) Generally, there is no special control on lens distortion, the optical distortion is greater than 5%, and the image edge deformation is large;

[0006] 4) Generally, lenses tend to shift focus at high and low temperatures, and the image quality is greatly affected by temperature. Summary of the invention

[0007] In view of this, the purpose of the present invention is to provide an ultra-close object distance imaging lens and electronic equipment. The lens can solve at least one technical disadvantage mentioned in the background technology.

[0008] According to one aspect of the present invention, an ultra-close object distance imaging lens is provided, which includes, 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 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 a flat surface, 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, wherein 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 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 is a convex surface, and the image-side surface is a convex surface;

[0013] The fifth 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 concave, and the image-side surface is convex;

[0014] The sixth lens has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side, wherein the object-side surface is a convex surface and the image-side surface is a convex surface;

[0015] The seventh lens element has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side, wherein the object-side surface is a convex surface and the image-side surface is a convex surface;

[0016] The eighth lens has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side, wherein the object-side surface is a convex surface and the image-side surface is a convex surface;

[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, wherein the object-side surface is a convex surface and the image-side surface is a concave surface;

[0018] The tenth 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 a convex surface, and the image-side surface is a flat surface.

[0019] In the above technical solution, the lens of this solution has a minimum working distance of 18.6mm, and can adapt to a target resolution of 12MP at a maximum of 1 / 2.3 inches; the working focal ratio is F#4.0, the numerical aperture NA=0.124; the focal length f=7mm enables the lens to have a wider depth of field and a wider range of objects to be viewed. The absolute value of optical distortion of this solution is less than 2%, which meets the characteristics of a distortion-free lens and is suitable for use in detection systems.

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

[0021] D R2 / R2≤1.60;e>1mm

[0022] Where D 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 edge thickness of the lens.

[0023] In the above technical solution, the edge thickness of the lens is >1.5mm, the front end of the lens can be expanded with a waterproof sealing ring to meet the waterproof requirements of the lens, the shape of the lens has left enough thickness on the edge of the lens, and D R2 / R2≤1.4, which improves the trustworthiness and reliability of the system and can meet the requirements of lens reliability experiments.

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

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

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

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

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

[0029] In the above technical solution, by appropriately setting the focal lengths of the second lens and the third lens, image quality can be optimized and system performance can be improved.

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

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

[0032] Wherein, 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 material, 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 conditional formula:

[0035] Vd5≤29.5; Vd6≥58; Vd6-Vd5>29

[0036] Wherein, 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 to form a second cemented lens group, wherein the tenth lens is made of fluorophosphate crown glass, and the lens satisfies the following conditional formula:

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

[0040] Wherein, Vd9 is the dispersion coefficient of the ninth lens, Vd 10 is the dispersion coefficient of the tenth lens.

[0041] 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. At the same time, the tenth lens uses fluorophosphate crown glass, which is characterized by dn / dT < -6*10E-6 in the temperature range of -40℃ to 80℃. The smaller the dn / dT of the positive focal length lens, the more effective it is in balancing temperature drift, which is conducive to achieving passive athermalization of the optical lens.

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

[0043] TTL / BFL≥4

[0044] Wherein, TTL is the total length of the lens; BFL is the optical back focus of the lens.

[0045] In the above technical solution, appropriate back focus is helpful to reduce the temperature drift caused by mechanical parts, which can reduce the temperature drift of the entire system and is conducive to heat-free.

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

[0047] D 10 / IMH>0.9

[0048] Where D 10 is the effective aperture of the tenth lens, and IMH is the target surface size of the lens

[0049] In the above technical solution, the above setting can make the overall light transition to the image plane relatively smoothly, reduce CRA, have strong tolerance and manufacturability, and be more mass-producible.

[0050] According to another aspect of the present invention, there is provided an electronic device, according to the above-mentioned ultra-close object distance imaging lens; and

[0051] An image sensor is configured to receive an image formed by the ultra-close object distance imaging lens.

[0052] In the above technical solution, the advantage of the electronic device depends on the ultra-close object distance imaging lens, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] 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.

[0054] Figure 11 is a schematic structural diagram of an ultra-close object distance imaging lens example 1 of the present invention;

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

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

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

[0058] Figure 5 is an axial chromatic aberration diagram of Example 1 of an ultra-close object distance imaging lens of the present invention;

[0059] Figure 6 is a point diagram of Example 1 of an ultra-close object distance imaging lens of the present invention;

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

[0061] Figure 8 It is a structural schematic diagram of Example 2 of an ultra-close object distance imaging lens of the present invention;

[0062] Fig. 9 is an MTF curve diagram of Example 2 of an ultra-close object distance imaging lens of the present invention;

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

[0064] Fig.11 is a vertical axis chromatic aberration diagram of Example 2 of an ultra-close object distance imaging lens of the present invention;

[0065] Fig.12 is an axial chromatic aberration diagram of Example 2 of an ultra-close object distance imaging lens of the present invention;

[0066] Fig.13 is a point diagram of Example 2 of an ultra-close object distance imaging lens of the present invention;

[0067] Fig.14 is a relative illumination diagram of Example 2 of an ultra-close object distance imaging lens of the present invention;

[0068] Fig.15 1 is a schematic structural diagram of an ultra-close object distance imaging lens example 3 of the present invention;

[0069] Fig.16 is an MTF curve diagram of Example 3 of an ultra-close object distance imaging lens of the present invention;

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

[0071] Fig.18 is a vertical axis chromatic aberration diagram of Example 3 of an ultra-close object distance imaging lens of the present invention;

[0072] Fig.19 is an axial chromatic aberration diagram of Example 3 of an ultra-close object distance imaging lens of the present invention;

[0073] Fig. 20 is a point diagram of Example 3 of an ultra-close object distance imaging lens of the present invention;

[0074] Fig.21 is a relative illumination diagram of Example 3 of an ultra-close object distance imaging lens of the present invention;

[0075] Fig. 22 It is a structural diagram of an electronic device example 4 of the present invention. DETAILED DESCRIPTION

[0076] 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.

[0077] The object of the present invention is to provide an ultra-close object distance 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.

[0078] Figure 1 , Figure 8 , Fig.15 They are cross-sectional views of super close object distance imaging lenses (optical systems) according to Examples 1 to 3, respectively. The super close object distance imaging lenses according to each example are used for optical devices including imaging devices such as digital cameras, digital still cameras, broadcast cameras, surveillance cameras, and interchangeable lenses. 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 a filter, G2 represents a protective lens, Ci represents the i-th group of cemented lenses, ST represents an aperture (fixed aperture or visible aperture), IMA represents an image plane, and when the super close object distance imaging lenses 1 to 3 according to each example are used for the imaging optical system of a digital camera or a 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 imaging plane IMA.

[0079] The ultra-close object imaging lens according to each example includes, in order from the object side to the image side: a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, and a tenth lens L10.

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

[0081] The fifth lens L5 and the sixth lens L6 are glued to form the first glued lens group C1. The ninth lens L9 and the tenth lens L10 are glued to form the second glued lens group C2, and the tenth lens adopts fluorophosphate crown glass. The tenth lens adopts fluorophosphate crown glass, which is characterized by dn / dT<-6*10E-6 in the temperature range of -40℃~80℃. The smaller the dn / dT of the positive focal length lens, the more effective it is in balancing the temperature drift, which is conducive to realizing the passive athermalization of the optical lens. The object measurement surface of the first lens and the image side surface of the tenth lens are both planes. The above arrangement allows the front and back of the lens to be better supported, making the entire structure more stable, the processability better, and improving the production yield.

[0082] The ultra-close object distance imaging lens according to each example may satisfy at least one of the following setting conditions 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 formula, D 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 thickness of the lens edge; 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 is the dispersion coefficient of the tenth lens; TTL is the total length of the lens; BFL is the optical back focus of the lens; D 10 is the effective aperture of the tenth lens, and IMH is the target surface size of the lens.

[0092] Conditional formula 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 setting the conditions appropriately, the first lens is a positive focal length lens and satisfies the lens edge thickness>1.5mm, the front end of the lens can be extended with a waterproof sealing ring to meet the lens waterproof requirements, the lens shape has left enough lens edge thickness, and D R2 / R2≤1.4, improve the reliability and dependability of the system, and meet the lens reliability test. 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 is higher than the upper limit, the lens cold processing and grinding lens yield is not high and cannot meet the mass production requirements. If the lens edge thickness is lower than the lower limit, it cannot meet the reliability requirements of the falling ball and gravel lens.

[0093] Conditional expression 2) defines the lens types of the second lens and the third lens. By setting the conditions appropriately, 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] Conditional formula 3) defines the focal length of the second lens and the third lens. By setting the conditions appropriately, the image quality can be optimized and the system performance can be improved. If it is higher than the upper limit, the single lens will bear more focal power, and the light will produce a larger light deflection angle on the corresponding surface, increasing the tolerance sensitivity of the lens. If it is lower than the lower limit, the requirements for miniaturization of the optical system cannot be met. In addition, in order to reliably obtain the effect of conditional formula 3), it is more preferable to set the values ​​of conditional formula 3) to f2 = -11.93mm, f3 = -14.41mm.

[0095] Conditional formula 4) defines the parameters of the fourth lens. By setting the conditions appropriately, the image quality is optimized and high resolution is achieved. 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 the lens's focal power cannot be reasonably controlled, increasing the difficulty of balancing the 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 lightweight lens. 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 f4 = 12.61 mm, Nd4 = 1.76.

[0096] Conditional formula 5) defines the Abbe number of the fifth lens and the sixth lens. By setting the conditions appropriately, the chromatic aberration can be effectively controlled, the distortion can be reduced, the image quality can be optimized, and the system performance can be improved. If the dispersion coefficient of the fifth lens is higher than the upper limit, it does not have abnormal dispersion characteristics. If the dispersion coefficient of the sixth lens is lower than the lower limit, the correction of partial dispersion cannot be effectively achieved, and the difficulty of correcting the partial dispersion of blue-violet light is increased. If the difference between the two is lower than the lower limit, the elimination of secondary chromatic aberration cannot be controlled, and the imaging quality cannot be effectively improved. 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 Vd5=29.5, Vd6=58.6, Vd6-Vd5=29.1.

[0097] Conditional equation 6) defines the Abbe number of the ninth lens and the tenth lens. By setting the conditions appropriately, chromatic aberration can be effectively controlled, distortion can be reduced, image quality can be optimized, and system performance can be 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 dispersion correction cannot be effectively achieved, increasing the difficulty of partial dispersion correction of blue-violet light. If the difference between the two is lower than the lower limit, the elimination of secondary chromatic aberration cannot be controlled, and the imaging quality cannot be effectively improved. In addition, in order to reliably obtain the effect of conditional equation 6), it is more preferred to set the value of conditional equation 6) to Vd9=53.4, Vd 10 =81.6, Vd 10 -Vd9=28.2.

[0098] Conditional formula 7) defines the ratio of the total length of the lens to the optical back focus. By setting the conditions appropriately, it is beneficial to reduce the temperature drift caused by the mechanical parts, and the temperature drift of the entire system can be reduced, which is beneficial to athermalization. If the ratio is lower than the lower limit, the total optical length will be increased, which is not conducive to controlling the lens length. 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 TTL / BFL=4.3.

[0099] Conditional formula 8) defines the ratio of the effective aperture of the tenth lens to the size of the target surface. By setting the conditions appropriately, the overall light can be relatively smoothly transitioned to the image plane, reducing CRA, with strong tolerance and manufacturability, and more mass production. If the ratio is lower than the lower limit, the maximum principal ray incident angle of the sensor will increase, and it cannot be adapted to mainstream sensors. In addition, in order to reliably obtain the effect of conditional formula 8), it is more preferable to set the value of conditional formula 8) to D 10 / IMH=1.2.

[0100] A detailed description will now be given of an ultra-close object distance imaging lens according to various examples.

[0101] For the optical structure of Example 1, please refer to Figure 1 The specific parameters of Example 1 are shown in Table 1. The focal length of the optical system is f=6.92 mm, the numerical aperture NA=0.124, the working focal ratio F#=4, the field of view FOV=57°, the target surface size IMH=7.81 mm, and the total optical length TTL=35.58 mm. The conditional formula is 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 Parameters

[0111] Surface 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 The 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 The 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 The eighth lens 30.688 1.360 Glass 1.76 52.3 18.32 16 -24.888 1.404 17 The 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 Optical Filters 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] See also Figure 2 , the MTF curve diagram of Example 1 represents the diffraction modulation transfer function (MTF) data of all fields of view. The larger the area enclosed by the MTF curve and the coordinate axis, the more information the optical system transmits, the better the imaging quality of the optical system, and the clearer the image. It can be seen from the figure that at the horizontal coordinate of 125lp / mm, the vertical coordinate values ​​of all curves are >0.3.

[0113] See also Figure 3 , the field curvature and distortion curve of Example 1. In the distortion diagram, the field of view is the ordinate and the distortion value is the abscissa. It can be seen from the figure that the F-Tan (Theta) distortion is <2% in the entire field of view.

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

[0115] See also Figure 5 The axial chromatic aberration diagram of Example 1 is also called positional chromatic aberration and spherical aberration. The horizontal axis represents the deviation from the image plane value, and the vertical axis represents the normalization of the maximum entrance pupil radius. It can be seen from the figure that the chromatic aberration curves of different wavelengths intersect from 435nm to 650nm, and their common focus deviates less from the red color of the main light d line, indicating that the optical system has excellent image quality and a good degree of apochromatism.

[0116] See also Figure 6 The point diagram of Example 1 can reflect the imaging situation of point objects. The denser the points, the better the optical imaging quality.

[0117] See also Figure 7 , the relative illumination curve of Example 1, the horizontal axis represents different fields of view, and the vertical axis represents the relative illumination size; it can be seen from the figure that the curve is relatively flat, and the RI is greater than 60% in the edge field of view, indicating that the system has high relative illumination, high brightness from center to edge, and uniform.

[0118] For the optical structure of Example 2, please refer to Figure 8 The specific parameters of Example 2 are shown in Table 2. The focal length of the optical system is f=7.2 mm, the numerical aperture NA=0.124, the working focal ratio F#=4, the field of view FOV=47°, the target surface size IMH=6.67 mm, and the total optical length TTL=35.94 mm. The conditional formula is 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 Parameters

[0128] Surface 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 The 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 The 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 The eighth lens 30.688 1.360 Glass 1.76 52.3 18.32 16 -24.888 1.801 17 The 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 Optical Filters 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] See also Fig. 9 , the MTF curve diagram of Example 2 represents the diffraction modulation transfer function (MTF) data of all fields of view. The larger the area enclosed by the MTF curve and the coordinate axis, the more information the optical system transmits, the better the imaging quality of the optical system, and the clearer the image. It can be seen from the figure that at the horizontal coordinate of 125lp / mm, the vertical coordinate values ​​of all curves are >0.3.

[0130] See also Fig.10 , the field curvature and distortion curve of Example 2, in the distortion diagram, the field of view is the ordinate and the distortion value is the abscissa. It can be seen from the figure that the F-Tan (Theta) distortion is <1.6% in the entire field of view.

[0131] See also Fig.11 In the vertical axis chromatic aberration diagram of Example 2, the horizontal axis represents the chromatic aberration values ​​at different wavelengths, and the vertical axis represents the size of the field of view. It can be seen from the figure that when the wavelength ranges from 435nm to 650nm, the chromatic aberration value of the 435nm wavelength (blue line) deviates from the main wavelength 555nm (red line) by less than 9um, making the color reproduction of the system slightly worse than that of Example 1.

[0132] See also Fig.12The axial chromatic aberration diagram of Example 2 is also called positional chromatic aberration and spherical aberration. The horizontal axis represents the deviation from the image plane value, and the vertical axis represents the normalization of the maximum entrance pupil radius. It can be seen from the figure that the chromatic aberration curves of different wavelengths intersect from 435nm to 650nm, and their common focus deviates less from the red color of the main light d line, indicating that the optical system has excellent image quality, and the degree of apochromatism is slightly worse than that of Example 1.

[0133] See also Fig.13 The point diagram of Example 2 can reflect the imaging situation of point objects. The denser the points, the better the optical imaging quality.

[0134] See also Fig.14 , the relative illumination curve of Example 2, the horizontal axis represents different fields of view, and the vertical axis represents the relative illumination size; it can be seen from the figure that the curve is relatively flat, and the RI is greater than 70% in the edge field of view, indicating that the system has high relative illumination, high brightness from center to edge, and uniform.

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

[0136] The conditional expression 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 Parameters

[0146]

[0147]

[0148] See also Fig.16 , the MTF curve diagram of Example 3 represents the diffraction modulation transfer function (MTF) data of all fields of view. The larger the area enclosed by the MTF curve and the coordinate axis, the more information the optical system transmits, the better the imaging quality of the optical system, and the clearer the image. It can be seen from the figure that at the abscissa 125lp / mm, the ordinate values ​​of all curves are >0.4.

[0149] See also Fig.17 , the field curvature and distortion curve of Example 3, in the distortion diagram, the field of view is the ordinate and the distortion value is the abscissa. It can be seen from the figure that the F-Tan (Theta) distortion is <1.5% in the whole field of view.

[0150] See also Fig.18 In the vertical axis chromatic aberration diagram of Example 2, the horizontal axis represents the chromatic aberration values ​​at different wavelengths, and the vertical axis represents the size of the field of view. It can be seen from the figure that when the wavelength ranges from 435nm to 650nm, the chromatic aberration value of the 435nm wavelength (blue line) deviates from the main wavelength 555nm (red line) by less than 10um, making the color reproduction of the system slightly worse than that of Example 1.

[0151] See also Fig.19 The axial chromatic aberration diagram of Example 3 is also called positional chromatic aberration and spherical aberration. The horizontal axis represents the deviation from the image plane value, and the vertical axis represents the normalization of the maximum entrance pupil radius. It can be seen from the figure that the chromatic aberration curves of different wavelengths intersect from 435nm to 650nm, and their common focus deviates less from the red color of the main light d line, indicating that the optical system has excellent image quality, and the degree of apochromatism is slightly worse than that of Example 1.

[0152] See also Fig. 20 The point diagram of Example 3 can reflect the imaging situation of point objects. The denser the points, the better the optical imaging quality.

[0153] See also Fig.21 , the relative illumination curve of Example 3, the horizontal axis represents different fields of view, and the vertical axis represents the relative illumination size; it can be seen from the figure that the curve is relatively flat, and the RI is greater than 68% in the edge field of view, indicating that the system has high relative illumination, high brightness from center to edge, and uniform.

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

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

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

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

[0158] 4. The lens of this solution meets the working temperature drift requirements of -40℃ to 85℃, and the imaging clarity is less affected by temperature.

[0159] Example 4

[0160] Reference Fig. 22 , a description will be given of an electronic device A according to Example 4 of the present invention. Fig. 22 is a schematic diagram of an electronic device (camera) using any of the ultra-close object distance imaging lenses according to Examples 1 to 3 for an imaging optical system.

[0161] exist Fig. 22 , reference numeral A2 denotes an electronic device body, and reference numeral A1 denotes an imaging optical system (interchangeable lens) including any one of the ultra-close object distance imaging lenses according to Examples 1 to 3. 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.

[0162] By using the ultra-close object distance imaging lens according to any one of Examples 1 to 3 for an electronic device such as a digital still camera or the like, an electronic device having high optical performance can be obtained.

[0163] Various examples may provide electronic devices having high optical performance.

[0164] 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. An ultra-close object distance 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, the ninth lens, and the 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 a flat surface, and the image-side surface is a convex surface; The second lens has a negative refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side, wherein the object-side surface is a convex surface and the image-side surface is a concave surface; 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 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 is a convex surface, and the image-side surface is a convex surface; The fifth 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 concave, and the image-side surface is convex; The sixth lens has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side, wherein the object-side surface is a convex surface and the image-side surface is a convex surface; The seventh lens element has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side, wherein the object-side surface is a convex surface and the image-side surface is a convex surface; The eighth lens has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side, wherein the object-side surface is a convex surface and the image-side surface is a convex surface; 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, wherein the object-side surface is a convex surface and the image-side surface is a concave surface; The tenth lens has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the object side, wherein the object-side surface is a convex surface and the image-side surface is a flat surface; The lens satisfies the following conditional formula: D R2 / R2≤1.60;e>1mm Where D 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; The second lens and the third lens are both crescent-shaped.

2. The ultra-close object distance imaging lens according to claim 1, characterized in that: The lens satisfies the following conditional formula: -20 <f2<-8;-20<f3<-8 Wherein, f2 is the focal length of the second lens; f3 is the focal length of the third lens.

3. The ultra-close object distance imaging lens according to claim 1, characterized in that: The lens satisfies the following conditional formula: 8 <f4<15;Nd4>1.75 Wherein, f4 is the focal length of the fourth lens, and Nd4 is the refractive index of the fourth lens.

4. The ultra-close object distance imaging lens according to 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 conditional formula: Vd5≤29.5; Vd6≥58; Vd6-Vd5>29 Wherein, Vd5 is the dispersion coefficient of the fifth lens, and Vd6 is the dispersion coefficient of the sixth lens.

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

6. The ultra-close object distance imaging lens according to claim 1, characterized in that: The lens satisfies the following conditional formula: TTL / BFL≥4 Wherein, TTL is the total length of the lens; BFL is the optical back focus of the lens.

7. The ultra-close object distance imaging lens according to claim 1, characterized in that: The lens satisfies the following conditional formula: D 10 / IMH>0.9 Where D 10 is the effective aperture of the tenth lens, and IMH is the target surface size of the lens.

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

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