Ultra-short object distance imaging lens and electronic equipment

Abstract

The utility model discloses an ultra-short object distance imaging lens and an electronic device. 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 utility model, 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 utility model relates to the technical field of near object distance imaging lenses, and in particular to an ultra - near object distance imaging lens and an electronic device. Background Art

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

[0003] 1) General lenses are designed for infinity, and the imaging of the lens is not good when used at near object distances;

[0004] 2) For general near object distance lenses, the focal length is very large. When the light transmission is constant, a large focal length results in a small depth of field and serious background blurring;

[0005] 3) General lenses do not have special control over distortion, and the optical distortion is greater than 5%, and the deformation amount of the image edge is large;

[0006] 4) General lenses are prone to focus shift at high and low temperatures, and the imaging quality is greatly affected by temperature. Summary of the Utility Model

[0007] In view of this, the purpose of the present utility model is to provide an ultra - near object distance imaging lens and an electronic device. This lens can solve at least one of the technical disadvantages mentioned in the background art.

[0008] According to one aspect of the present utility model, an ultra - near object distance imaging lens is provided. From the object side to the image side, there are successively 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 a 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 a negative 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 convex surface, and the image side surface is a concave surface;

[0011] The third lens has a negative diopter, and 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;

[0012] The fourth lens has a 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 a convex surface, and the image side surface is a convex surface;

[0013] The fifth lens has a negative diopter, with 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 a positive diopter, with 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 a positive diopter, with 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 a positive diopter, with 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 a negative diopter, with 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 a positive diopter, with 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.

[0019] In the above technical solution, the closest working distance of the lens in this solution can reach 18.6 mm, and the maximum can be adapted to a 1 / 2.3-inch target surface resolution of 12 MP; the working focal ratio is F#4.0, and the numerical aperture NA = 0.124; the focal length f = 7 mm enables the lens to have a wider depth of field and a wider viewing range of objects. The absolute value of the optical distortion in this solution is less than 2%, meeting the characteristics of a distortion-free lens and being suitable for use in a detection system.

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

[0021] D R2 / R2 ≤ 1.60; e > 1 mm

[0022] In the formula, D R2 is the aperture of the second surface of the first lens, R2 is the curvature radius 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 > 1.5 mm, and the front end of the lens can be extended and equipped with a waterproof seal ring to meet the waterproof requirements of the lens. Sufficient edge thickness of the lens has been reserved in terms of the lens shape, and D R2 / R2 ≤ 1.4, improving the reliability and dependability of the system and meeting the reliability experiment of the lens.

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

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

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

[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, by appropriately setting the focal lengths of the second lens and the third lens, the image quality can be optimized and the system performance can be improved.

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

[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 material, Nd4 > 1.75, to optimize the image quality and achieve high resolution.

[0034] In some embodiments, the fifth lens and the sixth lens are cemented into a first cemented lens group, and the lens satisfies the following conditional expressions:

[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 is combined with high and low dispersion materials, which can 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 into a second cemented lens group, where the tenth lens uses fluorophosphate crown glass, and the lens satisfies the following conditional expressions:

[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 is the dispersion coefficient of the tenth lens.

[0041] In the above technical solution, the cemented lens combines high and low dispersion materials, effectively controls chromatic aberration, reduces distortion, optimizes image quality, and improves 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°C to 80°C. The smaller the dn / dT of the positive focal length lens, the more effective it is to balance the temperature drift, which is beneficial to achieving passive athermalization of the optical lens.

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

[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, an appropriate back focal length is beneficial to reducing the temperature drift caused by mechanical parts, can reduce the temperature drift of the entire system, and is beneficial to athermalization.

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

[0047] D 10 / IMH > 0.9

[0048] In the formula, 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 settings can make the overall light 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, there is provided an electronic device, including the above ultra-close object distance imaging lens; and

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

[0052] In the above technical solution, the advantages of the electronic device rely on the ultra-close object distance imaging lens, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0054] Figure 1It is a schematic structural diagram of Example 1 of a super-close object distance imaging lens of the present utility model;

[0055] Figure 2 It is an MTF curve graph of Example 1 of a super-close object distance imaging lens of the present utility model;

[0056] Figure 3 It is a field curvature and distortion curve graph of Example 1 of a super-close object distance imaging lens of the present utility model;

[0057] Figure 4 It is a lateral chromatic aberration graph of Example 1 of a super-close object distance imaging lens of the present utility model;

[0058] Figure 5 It is an axial chromatic aberration graph of Example 1 of a super-close object distance imaging lens of the present utility model;

[0059] Figure 6 It is a spot diagram of Example 1 of a super-close object distance imaging lens of the present utility model;

[0060] Figure 7 It is a relative illumination graph of Example 1 of a super-close object distance imaging lens of the present utility model;

[0061] Figure 8 It is a schematic structural diagram of Example 2 of a super-close object distance imaging lens of the present utility model;

[0062] Figure 9 It is an MTF curve graph of Example 2 of a super-close object distance imaging lens of the present utility model;

[0063] Figure 10 It is a field curvature and distortion curve graph of Example 2 of a super-close object distance imaging lens of the present utility model;

[0064] Figure 11 It is a lateral chromatic aberration graph of Example 2 of a super-close object distance imaging lens of the present utility model;

[0065] Figure 12 It is an axial chromatic aberration graph of Example 2 of a super-close object distance imaging lens of the present utility model;

[0066] Figure 13 It is a spot diagram of Example 2 of a super-close object distance imaging lens of the present utility model;

[0067] Figure 14 It is a relative illumination graph of Example 2 of a super-close object distance imaging lens of the present utility model;

[0068] Figure 15 It is a schematic structural diagram of Example 3 of a super-close object distance imaging lens of the present utility model;

[0069] Figure 16It is the MTF curve graph of Example 3 of an ultra-short object distance imaging lens of the present utility model;

[0070] Figure 17 It is the field curvature and distortion curve graph of Example 3 of an ultra-short object distance imaging lens of the present utility model;

[0071] Figure 18 It is the lateral chromatic aberration graph of Example 3 of an ultra-short object distance imaging lens of the present utility model;

[0072] Figure 19 It is the longitudinal chromatic aberration graph of Example 3 of an ultra-short object distance imaging lens of the present utility model;

[0073] Figure 20 It is the spot diagram of Example 3 of an ultra-short object distance imaging lens of the present utility model;

[0074] Figure 21 It is the relative illumination graph of Example 3 of an ultra-short object distance imaging lens of the present utility model;

[0075] Figure 22 It is the structural schematic diagram of Example 4 of an electronic device of the present utility model. Specific embodiments

[0076] The following will further describe the present utility model in detail in conjunction with the accompanying drawings and embodiments. It should be specifically pointed out that the following embodiments are only used to illustrate the present utility model, but do not limit the scope of the present utility model. Similarly, the following embodiments are only partial embodiments of the present utility model rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present utility model.

[0077] The object of the present utility model is to provide an ultra-short object distance imaging lens and an electronic device with high optical performance. Now, embodiments according to the present utility model will be described in detail with reference to the accompanying drawings.

[0078] Figure 1 、 Figure 8 、 Figure 15These are cross-sectional views of ultra-close object distance imaging lenses (optical systems) according to Examples 1 to 3. The ultra-close object distance imaging lenses according to each example are used in imaging devices including imaging equipment such as digital cameras, digital still cameras, broadcast cameras, surveillance cameras, etc. and optical equipment with 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 a diaphragm (fixed diaphragm or visible diaphragm), IMA represents the image plane, and when the ultra-close object distance imaging lenses 1 to 3 according to each example are used in 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 distance imaging lenses according to each example include, in order from the object side to the image side: the first lens L1, the second lens L2, the third lens L3, the diaphragm ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, and the tenth lens L10.

[0080] The first lens L1 has a 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 plane, and the image side surface is a convex surface; the second lens L2 has a 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 a 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 a 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 a 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 a 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 seventh lens L7 has a 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 convex surface, and the image side surface is a convex surface; the eighth lens L8 has a 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 convex surface, and the image side surface is a convex surface; the ninth lens L9 has a 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 tenth lens L10 has a 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 convex surface, and the image side surface is a plane.

[0081] The fifth lens L5 and the sixth lens L6 are cemented to form a first cemented lens group C1. The ninth lens L9 and the tenth lens L10 are cemented to form a second cemented lens group C2, and the tenth lens is made of fluorophosphate crown glass. The tenth lens made of fluorophosphate crown glass is characterized in that dn / dT < -6 * 10E-6 in the temperature range of -40°C to 80°C. For a positive focal length lens, the smaller dn / dT is, the more effective it is to balance temperature drift, which is beneficial to achieving passive athermalization of the optical lens. The object side surface of the first lens and the image side surface of the tenth lens are both flat. The above settings enable better bearing and leaning of the front and back of the lens, making the entire structure more stable, with better processability and higher production yield.

[0082] The ultra-close object distance imaging lens according to each example can 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 expressions, D R2 is the aperture of the second surface of the first lens, R2 is the curvature radius 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 is the dispersion coefficient of the tenth lens; TTL is the total length of the lens; BFL is the optical back focal length of the lens; D 10 is the effective aperture of the tenth lens, and IMH is the target 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 edge thickness of the lens. By appropriately setting the conditions, the first lens is a positive focal length lens and satisfies the condition that the edge thickness of the lens > 1.5 mm. A waterproof sealing ring can be extended and matched at the front end of the lens to meet the waterproof requirements of the lens. Sufficient edge thickness of the lens has been reserved in terms of the lens shape, and D R2 / R2 ≤ 1.4, which improves the reliability and dependability of the system and can meet the lens reliability experiment. 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 value, the yield rate of the cold-processed and ground lens is not high and cannot meet the mass production requirements. If the edge thickness of the lens is lower than the lower limit value, the requirements for the reliability of the drop ball and gravel lens cannot be met.

[0093] Conditional formula 2) defines the lens types of the second lens and the third lens. By appropriately setting the conditions, the second lens and the third lens are crescent-shaped, which can achieve less distortion of the system, optimize the aberration, and improve the image quality.

[0094] Conditional formula 3) defines the focal lengths of the second lens and the third lens. By appropriately setting the conditions, the image quality can be optimized and the system performance can be improved. If it is higher than the upper limit value, a single lens undertakes more optical power, and a greater light deflection angle is generated on the corresponding surface, increasing the tolerance sensitivity of the lens. If it is lower than the lower limit value, the requirement for miniaturization of the optical system cannot be met. In addition, in order to reliably obtain the effect of this conditional formula 3), it is more preferable to set the values of conditional formula 3) as f2 = -11.93 mm and f3 = -14.41 mm.

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

[0096] Conditional formula 5) defines the Abbe numbers of the fifth lens and the sixth lens. By appropriately setting the conditions, chromatic aberration can be effectively controlled, 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 value, it does not have the characteristics of anomalous dispersion. If the dispersion coefficient of the sixth lens is lower than the lower limit value, the correction of partial dispersion cannot be effectively achieved, increasing the difficulty of correcting the partial dispersion of blue and violet light. If the difference between the two is lower than the lower limit value, the secondary chromatic aberration cannot be controlled and eliminated, and the imaging quality cannot be effectively improved. In addition, in order to reliably obtain the effect of this conditional formula 5), it is more preferable to set the values of conditional formula 5) as Vd5 = 29.5, Vd6 = 58.6, and Vd6 - Vd5 = 29.1.

[0097] Conditional expression 6) defines the Abbe numbers of the ninth lens and the tenth lens. By appropriately setting the conditions, 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 value, it is not conducive to controlling the chromatic aberration of the lens. If the dispersion coefficient of the tenth lens is lower than the lower limit value, the correction of partial dispersion cannot be effectively achieved, and the difficulty of correcting the partial dispersion of blue and violet light is increased. If the difference between the two is lower than the lower limit value, the secondary chromatic aberration cannot be controlled and eliminated, and the imaging quality cannot be effectively improved. In addition, in order to reliably obtain the effect of this conditional expression 6), it is more preferable to set the value of conditional expression 6) to Vd9 = 53.4, Vd 10 = 81.6, Vd 10 - Vd9 = 28.2.

[0098] Conditional expression 7) defines the ratio of the total length of the lens to the optical back focal length. By appropriately setting the conditions, it is beneficial to reduce the temperature drift caused by mechanical parts, the temperature drift of the entire system can be reduced, and athermalization is facilitated. If the ratio is lower than the lower limit value, the optical total length will increase, which is not conducive to controlling the lens length. In addition, in order to reliably obtain the effect of this conditional expression 7), it is more preferable to set the value of conditional expression 7) to TTL / BFL = 4.3.

[0099] Conditional expression 8) defines the ratio of the effective aperture of the tenth lens to the size of the target surface. By appropriately setting the conditions, the overall light can be made to transition to the image plane relatively smoothly, the CRA can be reduced, the tolerance and manufacturability are strong, and it is more suitable for mass production. If the ratio is lower than the lower limit value, the maximum chief 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 this conditional expression 8), it is more preferable to set the value of conditional expression 8) to D 10 / IMH = 1.2.

[0100] Now, a detailed description of the ultra-close object distance imaging lens according to each example will be given.

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

[0102] 1) D R2 / R2 ≤ 1.45; e > 1.5 mm;

[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 Parameter Table of Example 1

[0111] Surface number Type Radius of curvature Thickness Material Refractive index Abbe number 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 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 Diaphragm 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 refer to Figure 2 , the MTF curve graph of Example 1, which 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 axes, the more information the optical system transmits, the better the imaging quality of the optical system, the clearer the image. It can be seen from the figure that at the abscissa of 125 lp / mm, the ordinate values of all curves are > 0.3.

[0113] Please refer to Figure 3 , the field curvature and distortion curve graph of Example 1. In the distortion graph, 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% across the entire field of view.

[0114] Please refer to Figure 4 , the lateral chromatic aberration graph of Example 1. The horizontal axis represents the chromatic aberration values of different wavelengths, and the vertical axis represents the field of view size; it can be seen from the figure that from a wavelength of 435 nm to 650 nm, the chromatic aberration value of the 435 nm wavelength (blue line) deviating from the main wavelength of 555 nm (red line) is less than 8 um, making the system have high color reducibility.

[0115] Please refer to Figure 5 , the longitudinal chromatic aberration graph of Example 1, also called axial chromatic aberration and spherochromatism. The horizontal axis represents the deviation from the image value, and the vertical axis represents the normalization of the maximum entrance pupil radius. It can be seen from the figure that from a wavelength of 435 nm to 650 nm, the chromatic aberration curves of different wavelengths cross, and the common focus deviates relatively little from the d - line red of the chief ray, indicating that the optical system has excellent image quality and good apochromatism.

[0116] Please refer to Figure 6 , the spot diagram of Example 1 can reflect the imaging situation of a point object. The denser the points, the better the optical imaging quality.

[0117] Please refer to Figure 7 , the relative illuminance diagram curve of Example 1, where the horizontal axis represents different fields of view and the vertical axis represents the relative illuminance magnitude; 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 a high relative illuminance, high brightness from the center to the edge, and is uniform.

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

[0119] 1) D R2 / R2 ≤ 1.55; e > 1.0 mm;

[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 Parameter Table of Example 2

[0128] Surface number Type Radius of curvature Thickness Material Refractive index Abbe number 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 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 Diaphragm 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 refer to Figure 9 , the MTF curve diagram of Example 2, which 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 axes, 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 of 125 lp / mm, the ordinate values of all curves are > 0.3.

[0130] Please refer to Figure 10, Field curvature and distortion curve of Example 2. In the distortion graph, the field of view is the vertical coordinate and the distortion value is the horizontal coordinate. It can be seen from the graph that the F-Tan(Theta) distortion is <1.6% across the entire field of view.

[0131] Please refer to Figure 11 , For the lateral chromatic aberration graph of Example 2, the horizontal axis represents the chromatic aberration values at different wavelengths, and the vertical axis represents the field of view size; it can be seen from the graph that for wavelengths from 435nm to 650nm, the chromatic aberration value of the 435nm wavelength (blue line) deviating from the main wavelength of 555nm (red line) is less than 9um, making the color reduction ability of the system slightly worse than that of Example 1.

[0132] Please refer to Figure 12 , The longitudinal chromatic aberration graph of Example 2 is also called position chromatic aberration and spherical chromatic aberration. The horizontal axis represents the deviation from the image value, and the vertical axis represents the normalization of the maximum entrance pupil radius. It can be seen from the graph that for wavelengths from 435nm to 650nm, the chromatic aberration curves at different wavelengths cross, and the common focus deviates relatively little from the d-line red of the chief ray, indicating that the optical system has excellent image quality, and the apochromatic correction degree is slightly worse than that of Example 1.

[0133] Please refer to Figure 13 , The spot diagram of Example 2 can reflect the imaging situation of point objects. The denser the points, the better the optical imaging quality.

[0134] Please refer to Figure 14 , For the relative illumination graph curve of Example 2, the horizontal axis represents different fields of view, and the vertical axis represents the relative illumination magnitude; it can be seen from the graph that the curve is relatively flat, and RI is greater than 70% in the edge field of view, indicating that the system has a high relative illumination, with high brightness from the center to the edge and good uniformity.

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

[0136] The conditional equations are 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 Parameter Table of Example 3

[0146]

[0147]

[0148] Please refer to Figure 16 the MTF curve graph of Example 3, which 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 axes, 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 of 125 lp / mm, the ordinate values of all curves are > 0.4.

[0149] Please refer to Figure 17 the field curvature and distortion curve graph of Example 3. In the distortion graph, 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% across the entire field of view.

[0150] Please refer to Figure 18 the lateral chromatic aberration graph of Example 2. The horizontal axis represents the chromatic aberration values of different wavelengths, and the vertical axis represents the field of view size; it can be seen from the figure that from a wavelength of 435 nm to 650 nm, the chromatic aberration value of the 435 nm wavelength (blue line) deviating from the main wavelength of 555 nm (red line) is less than 10 um, making the color reduction of the system slightly worse than that of Example 1.

[0151] Please refer to Figure 19 the longitudinal chromatic aberration graph of Example 3, also known as the axial chromatic aberration and spherochromatism. The horizontal axis represents the deviation from the image value, and the vertical axis represents the normalization of the maximum entrance pupil radius. It can be seen from the figure that from a wavelength of 435 nm to 650 nm, the chromatic aberration curves of different wavelengths intersect, and the common focus deviates relatively little from the d - line red of the chief ray, indicating that the optical system has excellent image quality, and the apochromatism degree is slightly worse than that of Example 1.

[0152] Please refer to Figure 20 the spot diagram of Example 3, which can reflect the imaging situation of a point object. The denser the points, the better the optical imaging quality.

[0153] Please refer to Figure 21 the relative illuminance diagram curve of Example 3, where the horizontal axis represents different fields of view and the vertical axis represents the relative illuminance magnitude; 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 a high relative illuminance, high brightness from the center to the edge, and is uniform.

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

[0155] 1. The closest working distance of the lens in this solution is 18.6 mm, and the maximum can adapt to the target surface resolution of 12 MP for 1 / 2.3 inch.

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

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

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

[0159] Example 4

[0160] Now refer to Figure 22 for a description of the electronic device A according to Example 4 of the present invention. Figure 22 is a schematic diagram of an electronic device (camera) that uses any one of the ultra-close object distance imaging lenses according to Examples 1 to 3 in a camera optical system.

[0161] In Figure 22 , reference numeral A2 represents the main body of the electronic device, and reference numeral A1 represents a camera optical system (replaceable lens) including any one of the ultra-close object distance imaging lenses according to Examples 1 to 3. Reference numeral A3 represents an image sensor (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor, which is built into the camera body A2 and receives light (the optical image formed by the camera optical system A1) from the camera optical system A1 and performs photoelectric conversion.

[0162] By using the ultra-close object distance 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 an electronic device with high optical performance.

[0164] Although the present utility model has been described with reference to exemplary embodiments, it should be understood that the present utility model 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. An ultra-short object distance imaging lens, characterized in that, From the object side to the image side, there are 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 in sequence; The first lens has a 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 plane, and the image side surface is a convex surface; The second lens has a 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 has a 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 has a 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 has a 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 concave surface, and the image side surface is a convex surface; The sixth lens has a 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 seventh lens has a 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 convex surface, and the image side surface is a convex surface; The eighth lens has a 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 convex surface, and the image side surface is a convex surface; The ninth lens has a 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 tenth lens has a 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 convex surface, and the image side surface is a plane.

2. The ultra-short object distance imaging lens according to claim 1, wherein The lens satisfies the following conditional formula: D R2 / R2 ≤ 1.60; e > 1 mm 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.

3. The ultra-short object distance imaging lens according to claim 1, wherein Both the second lens and the third lens are crescent-shaped.

4. The ultra-short object distance imaging lens according to claim 1 or 3, wherein The lens satisfies the following conditional formula: -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.

5. The ultra-short object distance imaging lens according to claim 1, wherein The lens satisfies the following conditional formula: 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.

6. The ultra-short object distance imaging lens according to claim 1, wherein The fifth lens and the sixth lens are cemented into a first cemented lens group, and the lens satisfies the following conditional formula: 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.

7. The ultra-short object distance imaging lens according to claim 1, wherein The ninth lens and the tenth lens are cemented into a second cemented lens group, the tenth lens uses 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, and Vd 10 is the dispersion coefficient of the tenth lens.

8. The ultra-short object distance imaging lens according to claim 1, wherein: The lens satisfies the following conditional formula: TTL / BFL≥4 Wherein, TTL is the total length of the lens; BFL is the optical back focal length of the lens.

9. The ultra-short object distance imaging lens according to claim 1, wherein: 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 size of the target surface of the lens.

10. An electronic device, characterized in that, An ultra-short object distance imaging lens according to any one of claims 1-9; and An image sensor configured to receive an image formed by the ultra-short object distance imaging lens.

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