Optical lens, camera module and scanner

Abstract

The embodiment of the invention relates to the technical field of cameras, and provides an optical lens, a camera module and a scanner, the optical lens comprises eight lenses including a first lens group and a second lens group which are arranged from an object side to an image side, and a diaphragm is arranged between the first lens group and the second lens group; the first lens group has positive focal power, and the second lens group has positive focal power; the holographic height H of the optical lens and the maximum clear aperture CAmax of the optical lens meet the relational expression that CAmax / H is larger than or equal to 1.5 and smaller than or equal to 2.2. The optical lens achieves the purposes of large target surface, high resolution and miniaturization.

Description

Technical Field

[0001] The present application relates to the field of camera technology, and in particular to an optical lens, a camera module and a scanner. Background Art

[0002] Machine vision inspection technology is widely used in various fields of manufacturing. With the popularization of 3D imaging technology, optical lenses are usually set in 3D scanners to achieve 3D inspection of products. Especially for handheld 3D scanners, not only higher measurement accuracy is required, but also the equipment needs to be miniaturized so that the object can be flexibly and efficiently measured in 3D.

[0003] The optical lens with a fixed focal length in the related art, such as an optical lens with a focal length of 6 mm, has the problems of small target surface, insufficient resolution and difficulty in miniaturization. Summary of the invention

[0004] The embodiments of the present application provide an optical lens, a camera module and a scanner that can achieve a large target area, high resolution and miniaturization.

[0005] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides an optical lens, comprising a first lens group and a second lens group arranged from the object side to the image side, a total of 8 lenses, an aperture is provided between the first lens group and the second lens group; the first lens group has positive focal power, and the second lens group has positive focal power; the total image height H of the optical lens is equal to the maximum clear aperture CA of the optical lens max Satisfy the relationship: 1.5≤CA max / H≤2.2.

[0007] By reasonably allocating the focal power and the number of lenses of the first lens group and the second lens group, the focal length of the optical lens can be reduced while meeting the requirements; the first lens group and the second lens group located on both sides of the aperture have focal power. At the same time, by reasonably selecting the full image height H and the maximum aperture CA of the optical lens max , reducing the change angle of the light before and after the aperture, which not only improves the resolution of the optical lens and realizes the requirement of large target surface, but also reduces the aperture of the optical lens, which is conducive to miniaturization design, so that the optical lens can achieve the purpose of large target surface, high resolution and miniaturization.

[0008] In some embodiments, the total optical length TTL of the optical lens satisfies the relationship: 46mm≤TTL≤55mm.

[0009] In some embodiments, the optical lens has a minimum working distance WD near The corresponding optical distortion DIS near At the maximum working distance WD far The corresponding optical distortion DIS far The absolute value of the difference satisfies the relationship: |DIS near -DIS far |≤0.02%.

[0010] In some embodiments, the first lens group includes at least two lenses with negative optical power and two lenses with positive optical power; in the first lens group, the refractive index nd and the Abbe number vd of the lenses with negative optical power satisfy nd≥1.75, vd≤48.0.

[0011] In some embodiments, in the first lens group, in the direction arranged from the object side to the image side, the lens located at the first position is the first lens, and the lens located at the second position is the second lens, the first lens has negative optical power, and the second lens has negative optical power; the first lens is a meniscus structure.

[0012] In some embodiments, the focal length f1 of the first lens satisfies the relationship: f1≤-20.

[0013] In some embodiments, the focal length f2 of the second lens satisfies the relationship: f2≤-13.

[0014] In some embodiments, the second lens group includes at least two lenses with positive optical power and one lens with negative optical power. In the second lens group, the lens located at the last position in the direction arranged from the object side to the image side is a biconvex structure and has positive optical power.

[0015] In some embodiments, the second lens group includes a cemented lens, and the cemented lens is composed of two of the lenses.

[0016] In a second aspect, an embodiment of the present application provides a camera module, comprising a photosensitive element and the optical lens described in the first aspect, wherein the photosensitive element is arranged on the image side of the optical lens.

[0017] The camera module in the embodiment of the present application has the same structure and technical effects as the optical lens in the first aspect, and will not be described in detail here.

[0018] In a third aspect, an embodiment of the present application provides a scanner comprising the camera module described in the second aspect.

[0019] The camera module in the embodiment of the present application has the same structure and technical effects as the optical lens in the second aspect, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of an optical lens provided in Example 1 of the present application;

[0021] Figure 2 This is a MTF vs field diagram of the optical lens provided in Example 1 of the present application;

[0022] Figure 3 This is the MTF diagram of the optical lens provided in Example 1 of the present application;

[0023] Figure 4 The vertical axis chromatic aberration diagram of the optical lens provided in Example 1 of the present application is shown;

[0024] Figure 5 A relative illumination diagram of the optical lens provided in Example 1 of the present application;

[0025] Figure 6 A schematic diagram of the structure of an optical lens provided in Example 2 of the present application;

[0026] Figure 7 This is a MTF vs field diagram of the optical lens provided in Example 2 of the present application;

[0027] Figure 8 This is the MTF diagram of the optical lens provided in Example 2 of the present application;

[0028] Fig. 9 A vertical axis chromatic aberration diagram of the optical lens provided in Example 2 of the present application;

[0029] Fig.10 A relative illumination diagram of the optical lens provided in Example 2 of the present application;

[0030] Fig.11 A schematic diagram of the structure of an optical lens provided in Embodiment 3 of the present application;

[0031] Fig.12 This is a MTF vs field diagram of the optical lens provided in Example 3 of the present application;

[0032] Fig.13 This is the MTF diagram of the optical lens provided in Example 3 of the present application;

[0033] Fig.14 A vertical axis chromatic aberration diagram of the optical lens provided in Example 3 of the present application;

[0034] Fig.15 This is a relative illumination diagram of the optical lens provided in Example 3 of the present application.

[0035] Among them, the reference numerals in the figure are:

[0036] First lens group G1; second lens group G2; first lens L1; second lens L2; ​​third lens L3; fourth lens L4; fifth lens L5; sixth lens L6; seventh lens L7; eighth lens L8; aperture stop STOP; protective lens CG. DETAILED DESCRIPTION

[0037] For ease of understanding, the English abbreviations and related technical terms involved in the embodiments of the present application are explained and described below.

[0038] Focal power is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam. It characterizes the ability of an optical lens to deflect light.

[0039] A lens or lens group with positive optical power has a positive focal length and has the effect of converging light.

[0040] A lens or lens group with negative optical power has a negative focal length and has the effect of diverging light.

[0041] Focal length, also known as focal length, is a measure of the convergence or divergence of light in an optical lens. It refers to the vertical distance from the optical center of a lens or lens group to the focal plane when an infinitely distant scene forms a clear image on the focal plane through the lens or lens group. For a fixed-focus lens, the position of its optical center is fixed; for a telephoto lens, the change of the optical center of the lens brings about a change in the focal length of the lens.

[0042] The effective focal length (EFL) of a lens refers to the distance from the center of the lens to the focus.

[0043] The composite focal length is the combination of the focal lengths of the individual lenses in the lens group.

[0044] The object side is bounded by the lens. The side where the object is located is called the object side, and the surface of the lens close to the object side is called the object side.

[0045] The image side is bounded by the lens. The side where the image of the object is located is called the image side, and the surface of the lens close to the image side is called the image side.

[0046] The aperture (aperture diaphragm) is a device used to control the amount of light that passes through the lens and enters the photosensitive surface inside the camera body. It is usually inside the lens.

[0047] The imaging plane is located on the image side of all lenses in the optical lens, and is the plane on which the image is formed after the light passes through each lens in the optical lens in sequence.

[0048] The optical axis is an axis that passes vertically through the center of the lens. The optical axis of the lens is the axis that passes through the center of each lens of the lens.

[0049] Focus is the point where parallel light rays converge after being refracted by a lens or lens group.

[0050] The Abbe number, or dispersion coefficient, is the difference ratio of the refractive index of an optical material at different wavelengths, representing the degree of dispersion of the material.

[0051] Aberration: An optical lens has the properties of an ideal optical system at the optical axis. The near-axis light emitted from a point on the object intersects the image plane at one point (also known as the optical axis image point). However, the light rays that actually pass through the lens with different apertures are difficult to intersect perfectly at one point, but have a certain deviation from the position of the near-axis image point. These differences are collectively called aberrations.

[0052] Distortion, also known as distortion, is the degree of distortion of the image formed by an optical lens relative to the object itself. Distortion is due to the influence of aperture spherical aberration. The height of the intersection of the main light of different fields of view with the Gaussian image plane after passing through the optical lens is not equal to the ideal image height. The difference between the two is the distortion.

[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0054] In the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "multiple" means two or more.

[0055] like Figure 1 As shown, in some embodiments, the camera module includes an optical lens and a photosensitive element ( Figure 1 In IMA), the photosensitive element is located on the image side of the optical lens.

[0056] The working principle of the camera module is as follows: the light reflected by the photographed scene generates an optical image through the optical lens and is projected onto the photosensitive surface of the photosensitive element. The photosensitive element converts the optical image into an electrical signal, namely an analog image signal, and transmits it to the processor.

[0057] Among them, the photosensitive element (also called image sensor) is a semiconductor chip with hundreds of thousands to millions of photodiodes on its surface. When exposed to light, it will generate electric charge. The photosensitive element can be a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). CCD is made of a highly sensitive semiconductor material that can convert light into electric charge. Charge-coupled devices are composed of many photosensitive units, usually in units of millions of pixels. When the surface of the photosensitive element is exposed to light, each photosensitive unit will reflect the charge on the component, and the signals generated by all the photosensitive units are added together to form a complete picture.

[0058] The above-mentioned photosensitive element is also provided with a protective lens CG, so as to play a role in protecting the photosensitive element.

[0059] Among them, the optical lens mainly uses the refraction principle of the lens to form an image, that is, the light of the scene passes through the optical lens, forms a clear image on the focal plane, and the image of the scene is recorded by the photosensitive element located on the focal plane. The above optical lens can be, but is not limited to, an industrial lens.

[0060] like Figure 1 As shown, the embodiment of the present application provides an optical lens, comprising a first lens group G1 and a second lens group G2 arranged from the object side to the image side, a total of 8 lenses, an aperture is provided between the first lens group G1 and the second lens group G2; the first lens group G1 has positive focal power, and the second lens group G2 has positive focal power; the total image height H of the optical lens is equal to the maximum clear aperture CA of the optical lens max Satisfy the relationship: 1.5≤CA max / H≤2.2.

[0061] In the optical lens design process, the number of optical lenses is 8, which is determined based on the focal length of the optical lens being 6 mm. When the focal length of the optical lens changes, the number of lenses in the optical lens can also change according to the optical performance. The above optical lens can be, but is not limited to, a fixed-focus lens with a focal length of 6 mm.

[0062] Maximum aperture CA of optical lens max It is the maximum value of the clear aperture (Circula Aperturer, CA) of the optical lens.

[0063] By reasonably allocating the optical power and the number of lenses of the first lens group G1 and the second lens group G2, the focal length of the optical lens is made to meet the requirements, which is beneficial to reducing the aberration of the optical lens, thereby improving the resolution and high image quality; the first lens group G1 and the second lens group G2 located on both sides of the aperture STOP have optical power, which reduces the change angle of the light before and after the aperture, which is not only beneficial to reducing the tolerance sensitivity, thereby improving the imaging quality and large target surface of the optical lens, but also beneficial to reducing the aperture of the optical lens.

[0064] At the same time, if the maximum aperture CA of the optical lens max When the ratio of the optical lens to the full image height H is too large, the maximum aperture CA of the optical lens will be max Too large is not conducive to the miniaturization of the optical lens aperture; if the maximum aperture CA of the optical lens max If the ratio to the total image height H of the optical lens is too small, the maximum aperture CA of the optical lens will be reduced. max However, it will make the holographic height H too large, thus making the overall aperture of the camera module too large, which is not conducive to miniaturization design.

[0065] By rationally selecting the full image height H and maximum aperture CA of the optical lens max In this way, not only the resolution of the optical lens is improved and the large target surface requirement is achieved, but also the aperture of the optical lens is reduced, which is conducive to miniaturization design, so that the optical lens can achieve the purpose of taking into account large target surface, high resolution and miniaturization.

[0066] In the process of optical lens design, in addition to controlling the aperture of the optical lens, it is also necessary to control the total optical length of the optical lens. By reasonably designing the total optical length TTL, when the focal length of the optical lens is 6mm, when the total optical length TTL of the optical lens satisfies the relationship: 46mm≤TTL≤55mm, the total length of the optical lens can meet the requirements of miniaturization, for example, it can be used in 3D surveying instruments.

[0067] In addition, in the process of designing the optical performance of the optical lens, in order to improve the imaging quality of the optical lens, the distortion consistency of the optical lens in different object distance ranges is also an important indicator. near The corresponding optical distortion DIS near At the maximum working distance WD far The corresponding optical distortion DIS far When the absolute value of the difference is too large, the distortion consistency of the optical lens is poor, which is not conducive to improving the resolution and imaging quality of the optical lens.

[0068] Let the optical lens be at the minimum working distance WDnear The corresponding optical distortion DIS near At the maximum working distance WD far The corresponding optical distortion DIS far The absolute value of the difference satisfies the relationship: |DIS near -DIS far |≤0.02%, so that when the optical lens is used in a 3D scanner, it can not only meet the optical detection accuracy requirements, but also, when the 3D scanner is debugged, it only needs to correct the distortion at the optimal working distance, and no further correction is required during subsequent use, so that high measurement accuracy can be achieved.

[0069] In some embodiments, the first lens group G1 includes at least two lenses with negative power and two lenses with positive power; in the first lens group G1, the refractive index nd and the Abbe number vd of the lenses with negative power satisfy nd≥1.75 and vd≤48.0. Such a design allows as much light as possible to enter the optical lens, thereby facilitating the improvement of the resolution of the optical lens.

[0070] For example, Figure 1 As shown, the first lens group G1 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a fifth lens L5 arranged from the object side to the image side. The first lens L1 has negative power and is a meniscus structure, and the second lens L2 has negative power; the first lens L1 and the second lens L2 are made of heavy flint (H-ZF) or heavy lanthanum flint (H-ZLaF) materials, so that the refractive index nd and the Abbe number vd of the first lens L1 and the second lens L2 satisfy nd≥1.75 and vd≤48.0.

[0071] In the design of optical lenses, even if there is no oblique beam vignetting, the relative illumination of the image plane will decrease according to the law of cos^4(ω') as the image side half field angle ω' increases; when oblique beam vignetting exists, if the ratio of the cross-sectional area of ​​the off-axis oblique beam to the on-axis point beam is Ka, then E'=KaE0'cos^4(ω');

[0072] Among them, E' represents the illumination of the off-axis point, and E0' represents the illumination of the on-axis image point. It can be concluded that the most direct way to increase the relative illumination is to increase Ka and reduce ω'.

[0073] The first lens group G1 is designed as described above, especially the first lens L1 has a negative optical power, and the first lens L1 is a meniscus structure, which can not only generate a large amount of aperture coma to improve the illumination of the off-axis image point; but also generate sufficient negative distortion (barrel distortion) to significantly reduce the image side half field angle ω' corresponding to the object side half field angle ω, thereby improving the uniformity of the image plane illumination distribution.

[0074] At the same time, in the design process of the first lens group G1, the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 are also two important factors. On the basis of the upward structure of the first lens group G1 of the optical lens, when the focal length f1 of the first lens satisfies the relationship: f1≤-20; the focal length f2 of the second lens satisfies the relationship: f2≤-13, the relative illumination of the image plane of the optical lens is greatly improved, so that the target image can be clearly obtained without being disturbed by the image background or the noise of the detector, resulting in misjudgment.

[0075] Figure 1 The structure diagram of the optical lens of the first embodiment is shown. The optical lens comprises a first lens group G1, a stop and a second lens group G2 arranged from the object side to the image side, the first lens group G1 has positive focal power, and the second lens group G2 has positive focal power; the first lens group G1 comprises a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a fifth lens L5 arranged from the object side to the image side; the second lens group G2 comprises a sixth lens L6, a seventh lens L7 and an eighth lens L8 arranged from the object side to the image side, and the sixth lens L6 and the seventh lens L7 are cemented together to form a cemented lens.

[0076] Table 1a to Table 1d respectively give specific parameter values ​​of each lens of an optical lens of an optional embodiment in Example 1 of the present application.

[0077] Table 1a

[0078] Surface number Surface type R-Value thickness Refractive Index Abbe number Sur1 Standard 19.8 1.73 1.806105 33.2869 Sur2 Standard 11.632 3.31 Sur3 Standard 39.67 0.9 1.92286 18.8959 Sur4 Standard 12.752 2.89 Sur5 Standard -262.2 0.9 1.58913 61.2531 Sur6 Staudard 21.985 10.44 Sur7 Standard 145.373 2.83 1.54678 62.7761 Sur8 Standard -17.247 2.36 Sur9 Standard 17.21 2.03 1.90366 31.3571 Sur10 Standard 97.363 8.54 STOP Standard Infinity 2.24 Sur12 Standard -7.386 1.39 1.84666 23.7845 Sur13 Standard 8.644 2.21 1.63854 55.4466 Sur14 Standard -5.97 0.15 Sur15 Standard 18.5 1.56 1.7725 49.599 Sur16 Standard -61.465 8.62 Sur17 Standard Infinity 1.5 1.5168 64.1987 Sur18 Standard Infinity 0.2 Image Standard Iufinity 0

[0079] It should be noted that, in Table 1a, the "surface number" is the number of each surface arranged in sequence from the object side to the image side, the radius R value is the lens with the corresponding surface number, that is, the curvature radius of the object side surface or the image side surface of the lens corresponding to each surface number at the optical axis, and the "infinity" of the lens in the "radius of curvature" parameter series means that the object side surface or the image side surface of the lens is a plane; the first value of each lens in the "thickness / spacing" parameter series is the thickness of the lens on the optical axis, and the second value is the distance from the image side surface of the lens to the object side surface of the next lens on the optical axis; the value of the aperture STOP in the "thickness" parameter series is the distance from the center of the aperture STO to the object side surface of the next lens on the optical axis.

[0080] The optical indicators of the optical lens in this embodiment are as follows:

[0081] Total optical length: TTL = 53.8mm;

[0082] Optimal working distance: WD0 = 270 mm;

[0083] Aperture number: Fno. = 5.6;

[0084] Focal length: f=6mm;

[0085] Target surface: 1 / 1.8 inch;

[0086] Working band: visible light;

[0087] Relative illumination: RI ≥ 82%;

[0088] Optical distortion: |DIS|<4.0%;

[0089] Optical distortion difference value: In the working distance 150mm ~ 450mm depth of field range, |DIS near -DIS far |≤0.014%; within the working distance of 200mm~400mm depth of field, |DISnear-DISfar|≤0.008%

[0090] The parameters of the optical lens in Example 1 satisfy the relationship shown in Table 1b.

[0091] Table 1b

[0092]

[0093] Note: The following are the explanations of the relationship between the optical lenses in each embodiment:

[0094] f1 is the focal length of the first lens L1;

[0095] f2 is the focal length of the second lens L2;

[0096] H is the full image height of the optical lens;

[0097] TTL is the total optical length of the optical lens;

[0098] CA max The maximum value of the optical lens’s clear aperture (Circula Aperturer, CA);

[0099] |DIS near -DIS far | is the minimum working distance WD of the optical lens near The corresponding optical distortion DIS near At the maximum working distance WD far The corresponding optical distortion DIS far The absolute value of the difference.

[0100] The positive and negative conditions of the focal length of each lens in the optical lens of Example 1 are shown in Table 1c.

[0101] Table 1c

[0102]

[0103] It should be noted that the "+" and "-" in Table 1c represent the positive and negative conditions of the focal length of each lens in the optical lens in Example 1. Among them, "+" represents that the lens has a positive focal length; "-" represents that the lens has a negative focal length.

[0104] The concave-convex condition of the object side surface or image side surface of each lens in the optical lens of Example 1 at the optical axis is shown in Table 1d.

[0105] Table 1d

[0106]

[0107] It should be noted that the "++", "+-", "-+", "∞-", "+∞", and "--" in Table 1d represent the concave-convex situation of the object side or image side of each lens at the optical axis. Among them, "++" represents that both the object side and the image side of the lens are convex toward the object at the optical axis, also known as a meniscus structure; "+-" represents that the object side of the lens is convex toward the object at the optical axis, and the image side is convex toward the object at the optical axis, that is, a double convex structure; "-+" represents that the object side of the lens is concave toward the object at the optical axis, and the image side is convex toward the object at the optical axis, that is, a double concave structure; "∞+" represents that the object side of the lens is a plane at the optical axis, and the image side is convex toward the object at the optical axis; "+∞" represents that the object side of the lens is convex toward the object at the optical axis, and the image side is a plane at the optical axis; "--" represents that both the object side and the image side of the lens are concave toward the object at the optical axis. Of course, in addition to the above-mentioned concave and convex conditions, each lens in the optical lens may also include any one or more of "∞-" and "-∞", where the object side of the lens represented by "∞-" is a plane at the optical axis, and the image side is concave toward the object at the optical axis; the object side of the lens represented by "-∞" is concave toward the object at the optical axis, and the image side is a plane at the optical axis, and no specific limitation is made here.

[0108] Combination Figure 1 The schematic diagram of the structure of the optical lens in the first embodiment, and the main parameters of the optical lens in the first embodiment given in Tables 1a to 1d satisfy the relationship in Table 1b, and the concave-convex condition of each lens at the optical axis. The simulation of the optical lens in the first embodiment is obtained by simulation. Figure 2 to Figure 5 .

[0109] in: Figure 2 The MTFv of the optical lens provided in Example 1 of the present application is given as follows: s field diagram, also called MTH diagram. Figure 3The MTF curves corresponding to the meridian plane and sagittal plane of the optical lens provided in Example 1 of the present application at six different positions at frequencies of 0-200 lp / mm are given, and a comparison chart of the MTF curves under diffraction limit conditions is given. MTF is Modulatio n Transfe r Functio n The English abbreviation of Modulation Transfer Function, which is Modulation Transfer Function in Chinese, refers to the function of how modulation changes with spatial frequency. Both MTH and MTF graphs are curves that reflect the restoration of contrast (reproduction degree) by the optical lens. The horizontal axis of the MTF graph is the distance from the center to the edge, and the vertical axis of the MTF graph reflects the quality of the contrast, or in other words, the quality of the restoration degree. However, the horizontal axis of the MTH graph is the normalized field of view, and the vertical axis of the MTH graph is the same as that of the MTF graph. The higher the vertical axis values ​​of the MTH and MTF graphs, the better the restoration degree of the optical lens and the higher the resolution. From Figure 2 and Figure 3 It can be seen that the MTF value is greater than 0.1 and the light tends to be diffraction limited.

[0110] Figure 4 The vertical axis chromatic aberration diagram of the optical lens provided in Example 1 of the present application is given. Figure 5 It can be seen that the aberration of this optical lens is small.

[0111] Figure 5 The relative illumination diagram of the optical lens provided in Example 1 of the present application is given. Figure 5 It can be seen that the relative illumination of the optical lens is greater than 82%, indicating that the brightness uniformity of the entire picture is high, there is no dark corner, and it meets the usage requirements.

[0112] The above descriptions about the MTF vs field diagram, the vertical axis chromatic aberration diagram and the relative illumination diagram are the same as those in other embodiments and will not be repeated hereinbelow.

[0113] Figure 6 The structure diagram of the optical lens of the second embodiment is shown. The main difference between the optical lens of the second embodiment and the optical lens of the first embodiment is that the parameters and conditions of each lens are different, and the concave-convex situation of the object side or image side of each lens at the optical axis.

[0114] Tables 2a to 2d respectively give specific parameter values ​​of each lens of an optical lens of an optional embodiment in Example 2 of the present application.

[0115] Table 2a

[0116] Surface number Surface type R-Value thickness Refractive Index Abbe number Sur1 Standard 20.294 2.05 1.90366 31.3571 Sur2 Standard 11.59 2.83 Sur3 Standard 34.434 0.9 1.92286 18.8959 Sur4 Standard 13.222 2.64 Sur5 Standard -156.232 0.9 1.58913 61.2531 Sur6 Standard 21.268 10.31 Sur7 Standard 78.248 2.64 1.54678 62.7761 Sur8 Standard -18.14 3 Sur9 Standard 17.193 1.79 1.90366 31.3571 Sur10 Standard 85.9 8.49 STOP Standard Infinity 2.97 Sur12 Standard -7.148 1.12 1.84666 23.7845 Sur13 Standard 9.67 2.44 1.63854 55.4466 Sur14 Standard -6.576 0.15 Sur15 Standard 19.74 1.57 1.83481 42.7252 Sur16 Standard -30.45 8.3 Sur17 Standard Infinity 1.5 1.5168 64.1987 Sur18 Standard Infinity 0.2 Image Standard Infinity -

[0117] The optical indicators of the optical lens in this embodiment are as follows:

[0118] Total optical length: TTL = 53.8mm;

[0119] Optimal working distance: WD0 = 270 mm;

[0120] Aperture number: Fno. = 5.6;

[0121] Focal length: f=6mm;

[0122] Target surface: 1 / 1.8 inch;

[0123] Working band: 430nm~470nm;

[0124] Relative illumination: RI ≥ 82%;

[0125] Optical distortion: |DIS|<4.2%;

[0126] Optical distortion difference value: In the working distance 150mm ~ 450mm depth of field range, |DIS near -DIS far |≤0.018%; within the working distance 200mm~400mm depth of field range, |DIS near -DIS far |≤0.011%.

[0127] The parameters of the optical lens in Example 2 satisfy the relationship shown in Table 2b.

[0128] Table 2b

[0129]

[0130] The optical power of each lens of the optical lens in Example 2 is shown in Table 2c.

[0131] Table 2c

[0132]

[0133] The concave-convex condition of the object side surface or image side surface of each lens of the optical lens in Example 2 at the optical axis is shown in Table 2d.

[0134] Table 2d

[0135]

[0136] Combination Figure 6 The schematic diagram of the structure of the optical lens in the second embodiment, and the main parameters of the optical lens in the second embodiment given in Tables 2a to 2d satisfy the relationship in Table 2b, and the concave-convex condition of each lens at the optical axis. The simulation of the optical lens in the second embodiment is obtained by simulation. Figure 7 to Figure 10 .

[0137] from Figure 7 and Figure 8 It can be seen that the MTF value is greater than 0.1 and the light tends to be diffraction limited.

[0138] from Fig. 9 It can be seen that the aberration of this optical lens is small.

[0139] from Fig.10 It can be seen that the relative illumination of the optical lens is greater than 82%, indicating that the brightness uniformity of the entire picture is high, there is no dark corner, and it meets the usage requirements.

[0140] Fig.11 The structure diagram of the optical lens of the third embodiment is shown. The main difference between the optical lens of the third embodiment and the optical lens of the first embodiment is the number of lenses in the first lens group G1 and the second lens group G2, the parameters of each lens and the conditions to be satisfied, and the concave-convex condition of the object side surface or image side surface of each lens at the optical axis.

[0141] like Fig.11 As shown, the optical lens includes a first lens group G1, an aperture and a second lens group G2 arranged from the object side to the image side, the first lens group G1 has positive focal power, and the second lens group G2 has positive focal power; the first lens group G1 includes a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4 arranged from the object side to the image side; the second lens group G2 includes a fifth lens L5, a sixth lens L6, a seventh lens L7 and an eighth lens L8 arranged from the object side to the image side, and the sixth lens L6 and the seventh lens L7 are cemented together to form a lens.

[0142] Tables 3a to 3d respectively give specific parameter values ​​of each lens of an optical lens of an optional embodiment in Example 3 of the present application.

[0143] Table 3a

[0144] Surface number Surface type R-Value thickness Refractive Index Abbe number Sur1 Standard 22.493 4 1.90366 31.3571 Sur2 Standard 9.22 3.26 Sur3 Standard 1433.99 1.1 1.90366 31.3571 Sur4 Standard 13.015 9.26 Sur5 Standard -269.45 4 1.6968 56.1753 Sur6 Standard -14.36 6.13 Sur7 Standard 10.385 2.21 1.83481 42.7116 Sur8 Standard 29.02 5 STOP Standard Infinity 0.64 Sur10 Standard -17.53 2.04 1.69362 49.1938 Sur11 Standard -6.898 0.73 Sur12 Standard -5 0.9 1.76182 26.608 Sur13 Standard 7.43 3.46 1.497 81.6054 Sur14 Standard -5.75 1.2 Sur15 Standard 12.878 1.51 1.7433 49.2218 Sur16 Standard 582.48 5.86 Sur17 Standard Infinity 1.5 1.5168 64.1987 Sur18 Standard Infinity 0.2 Image Standard Infinity

[0145] The optical indicators of the optical lens in this embodiment are as follows:

[0146] TTL=53mm; optimal working distance: WD0=270mm;

[0147] Aperture number: Fno. = 5.6;

[0148] Focal length: f=6mm;

[0149] Target surface: 1 / 1.8 inch;

[0150] Working band: visible light;

[0151] Relative illumination: RI ≥ 85%;

[0152] Optical distortion: |DIS|<4.2%;

[0153] Absolute value of optical distortion difference: Within the working distance 150mm ~ 450mm depth of field range, |DIS near -DIS far |≤0.018%; within the working distance 200mm~400mm depth of field range, |DIS near -DIS far |≤0.011%.

[0154] The parameters of the optical lens in Example 3 satisfy the relationship shown in Table 3b.

[0155] Table 3b

[0156]

[0157] The positive and negative conditions of the focal length of each lens in the optical lens of Example 3 are shown in Table 3c.

[0158] Table 3c

[0159]

[0160] The concave-convex condition of the object side surface or image side surface of each lens in the optical lens of Example 3 at the optical axis is shown in Table 3d.

[0161] Table 3d

[0162]

[0163] Combination Fig.11 The schematic diagram of the structure of the optical lens in the third embodiment, and the main parameters of the optical lens in the second embodiment given in Tables 3a to 3d satisfy the relationship in Table 3b, and the concave-convex condition of each lens at the optical axis. The simulation of the optical lens of the third embodiment is obtained by simulation. Figure 12 to Figure 15 .

[0164] from Fig.12 and Fig.13 It can be seen that the MTF value is greater than 0.1 and the light tends to be diffraction limited.

[0165] from Fig.14 It can be seen that the aberration of this optical lens is small.

[0166] from Fig.15 It can be seen that the relative illumination of the optical lens is greater than 85%, indicating that the brightness uniformity of the entire picture is high, there is no dark corner, and it meets the usage requirements.

[0167] In summary, the optical lens with a focal length of 6mm in this application has a total optical length of about 53mm, which realizes the miniaturized design of the optical lens; the relative illumination RI of the image plane is greatly improved, which can reach RI ≥ 80% at 1 / 1.8 inch, and the resolution is better than 6 million; the distortion consistency is good within the depth of field range of 150mm to 450mm, which can meet the requirements of 3D scanning.

[0168] The present application also provides a scanner, including a camera module.

[0169] The above-mentioned scanning instrument can be but is not limited to a 3D scanner.

[0170] The structure of the camera module is the same as the structure and effect of any of the above embodiments, and no specific limitation is made here.

[0171] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical lens, characterized in that: The invention comprises a first lens group and a second lens group arranged from the object side to the image side, a total of 8 lenses, an aperture is provided between the first lens group and the second lens group; the first lens group has positive focal power, and the second lens group has positive focal power; The total image height H of the optical lens and the maximum aperture CA of the optical lens max Satisfy the relationship: 1.5≤CA max / H≤2.

2.

2. The optical lens according to claim 1, characterized in that: The total optical length TTL of the optical lens satisfies the relationship: 46mm≤TTL≤55mm.

3. The optical lens according to claim 1, characterized in that: The optical lens has a minimum working distance WD near The corresponding optical distortion DIS near At the maximum working distance WD far The corresponding optical distortion DIS far The absolute value of the difference satisfies the relationship: |DIS near -DIS far |≤0.02%.

4. The optical lens according to claim 1, characterized in that: The first lens group includes at least two lenses having negative power and two lenses having positive power; In the first lens group, the refractive index nd and the Abbe number vd of the lens with negative optical power satisfy nd≥1.75 and vd≤48.

0.

5. The optical lens according to claim 4, characterized in that: In the first lens group, in the direction arranged from the object side to the image side, the lens located at the first position is the first lens, and the lens located at the second position is the second lens, the first lens has negative optical power, and the second lens has negative optical power; the first lens is a meniscus structure.

6. The optical lens according to claim 5, characterized in that: The focal length f1 of the first lens satisfies the relationship: f1≤-20; And / or, the focal length f2 of the second lens satisfies the relationship: f2≤-13.

7. The optical lens according to claim 4, characterized in that: The second lens group includes at least two lenses with positive optical power and one lens with negative optical power. In the second lens group, the lens located at the last position in the direction arranged from the object side to the image side is a biconvex structure and has positive optical power.

8. The optical lens according to claim 7, characterized in that: The second lens group includes a cemented lens, and the cemented lens is composed of two of the lenses.

9. A camera module, characterized in that: include: The optical lens according to any one of claims 1 to 8; A photosensitive element is arranged on the image side of the optical lens.

10. A scanner, characterized in that: include: The camera module as claimed in any one of claim 9.

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