Optical imaging device

Abstract

The present invention provides an optical imaging device, which includes a lens group, a spacer element group and a lens barrel. The lens group includes a first lens to an eighth lens arranged in sequence from the object side to the image side of the optical imaging device, wherein the focal length f of the optical imaging device, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy the following: ‑6.44≤(f1+f2) / f≤‑5.03; the axial distance EP01 from the object side end face of the lens barrel to the object side face of the first spacer element, the axial distance EP12 from the image side face of the first spacer element to the object side face of the second spacer element, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy the following: ‑0.50≤EP01 / f1+EP12 / f2≤‑0.40. The present application solves the problem of poor processability of the front end lens of the optical imaging device in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging equipment, and in particular to an optical imaging device. Background Art

[0002] Ultra-wide-angle optical imaging devices are becoming an important development direction in the field of smartphone photography. With the advancement of manufacturing technology, the lenses in optical imaging devices can be processed and combined more precisely, thereby improving the imaging quality of optical imaging devices. In pursuit of more perfect imaging, more accurate colors, and a wider field of view, eight-piece optical imaging devices have gradually become the mainstream trend in the industry. However, the eight-piece optical imaging devices in the prior art have poor front-end focal length control effects. In order to improve the wide-angle imaging effect, the front-end lens has a large degree of curvature, but it is easy to cause large surface errors during the processing and molding process, and the risk of appearance problems such as weld marks and flow marks is also high, which further causes stray light to affect the imaging effect. Therefore, how to ensure the processability of the front-end lens while improving the front-end focal length control effect of the optical imaging device is an urgent problem to be solved. Summary of the invention

[0003] The main purpose of the present invention is to provide an optical imaging device to solve the problem of poor processability of the front end lens of the optical imaging device in the prior art.

[0004] In order to achieve the above-mentioned object, the present invention provides an optical imaging device, wherein the number of lenses with optical power in the optical imaging device is eight, and the optical imaging device comprises: a lens group, wherein the lens group comprises a first lens to an eighth lens arranged in sequence from the object side to the image side of the optical imaging device, wherein the first lens has negative optical power, the object side surface of the first lens is convex, and the image side surface of the first lens is concave, the second lens has negative optical power, and the image side surface of the second lens is concave, the third lens has positive optical power, and the object side surface of the third lens is convex, the fourth lens has positive optical power, and the object side surface of the fourth lens is convex, the fifth lens has positive optical power, and the object side surface of the eighth lens is convex, and the image side surface of the eighth lens is concave; and a spacer element group, wherein the spacer element group comprises at least a first spacer element located between the first lens and the second lens and at least partially in contact with the image side surface of the first lens, a second spacer element located between the second lens and the third lens and at least partially in contact with the image side surface of the second lens, a third spacer element located between the third lens and the fourth lens and at least partially in contact with the image side surface of the third lens, a fourth spacer element located between the fourth lens and the fifth lens and at least partially in contact with the image side surface of the eighth lens, and a spacer element located between the fourth lens and the fifth lens and at least partially in contact with the image side surface of the eighth lens. a fourth spacing element at least partially in contact with the image side surface of the fourth lens, a fifth spacing element located between the fifth lens and the sixth lens and at least partially in contact with the image side surface of the fifth lens, a sixth spacing element located between the sixth lens and the seventh lens and at least partially in contact with the image side surface of the sixth lens, and a seventh spacing element located between the seventh lens and the eighth lens and at least partially in contact with the image side surface of the seventh lens; a lens barrel, a lens group and a spacing element group are accommodated in the lens barrel, the lens barrel comprises an object side end surface, an image side end surface, an outer annular surface and an inner annular surface, and along the optical axis direction of the optical imaging device, the lens barrel The inner annular surface is stepped; wherein, the focal length f of the optical imaging device, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy: -6.44≤(f1+f2) / f≤-5.03; the axial distance EP01 from the object side end face of the lens barrel to the object side face of the first spacing element, the axial distance EP12 from the image side face of the first spacing element to the object side face of the second spacing element, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy: -0.50≤EP01 / f1+EP12 / f2≤-0.40.

[0005] Furthermore, the maximum half field angle Semi-FOV of the optical imaging device, the outer diameter D0m of the image side end surface of the lens barrel, and the axial distance TD from the object side surface of the first lens to the image side surface of the eighth lens satisfy: 2.66≤TD*tan(Semi-FOV) / D0m≤11.95.

[0006] Furthermore, the maximum half field of view Semi-FOV of the optical imaging device, the focal length f of the optical imaging device, and the axial distance L from the object side end surface of the lens barrel to the image side end surface of the lens barrel satisfy: 0.41≤L / (f*tan(Semi-FOV))≤1.14.

[0007] Furthermore, the on-axis distance from the image side surface of the first lens to the object side surface of the second lens is the maximum value of the on-axis distances between all two adjacent lenses, and the on-axis distance EP01 from the object side end surface of the lens barrel to the object side surface of the first spacing element and the on-axis distance T12 from the image side surface of the first lens to the object side surface of the second lens satisfy: 1.02≤EP01 / T12≤1.49.

[0008] Furthermore, an axial distance EP13 from the image side surface of the first spacing element to the object side surface of the third spacing element and a combined focal length f23 of the second lens and the third lens satisfy: -0.43≤EP13 / f23≤-0.13.

[0009] Furthermore, an axial distance EP23 from the image side surface of the second spacer element to the object side surface of the third spacer element, a center thickness CT3 of the third lens, and a refractive index N3 of the third lens satisfy: 0.56≤EP23 / (CT3*N3)≤0.98.

[0010] Furthermore, the on-axis distance EP34 from the image side surface of the third spacing element to the object side surface of the fourth spacing element, the curvature radius R7 of the object side surface of the fourth lens, and the curvature radius R8 of the image side surface of the fourth lens satisfy: 0.03≤EP34 / (R7+R8)≤0.56.

[0011] Furthermore, an axial distance EP46 from the image side surface of the fourth spacer element to the object side surface of the sixth spacer element, a center thickness CT5 of the fifth lens, and a center thickness CT6 of the sixth lens satisfy: 0.95≤EP46 / (CT5+CT6)≤1.40.

[0012] Furthermore, the refractive power of the sixth lens and the refractive power of the seventh lens have opposite signs, and the effective focal length f6 of the sixth lens and the effective focal length f7 of the seventh lens satisfy: -2.04≤f6 / f7≤-0.67.

[0013] Furthermore, an inner diameter d6m of the image side surface of the sixth spacing element, an inner diameter d7m of the image side surface of the seventh spacing element, a curvature radius R13 of the object side surface of the seventh lens, and a curvature radius R15 of the object side surface of the eighth lens satisfy: 1.68≤d6m / R13+d7m / R15≤4.82.

[0014] Furthermore, an inner diameter d6m of the image side surface of the sixth spacer element, an inner diameter d7m of the image side surface of the seventh spacer element, and an axial distance EP67 from the image side surface of the sixth spacer element to the object side surface of the seventh spacer element satisfy: 0.13≤(d7m-d6m) / EP67≤2.29.

[0015] Further, the inner diameter d0m of the image side end surface of the lens barrel, the inner diameter d7m of the image side surface of the seventh spacing element, and the effective focal length f8 of the eighth lens satisfy: -0.91≤(d0m-d7m) / f8≤1.30.

[0016] According to the technical solution of the present invention, the optical imaging device has eight lenses with optical power, and the optical imaging device includes a lens group, a spacer element group and a lens barrel. The lens group includes a first lens to an eighth lens arranged in sequence from the object side to the image side of the optical imaging device, wherein the first lens has negative optical power, the object side surface of the first lens is convex, and the image side surface of the first lens is concave, the second lens has negative optical power, and the image side surface of the second lens is concave, the third lens has positive optical power, and the object side surface of the third lens is convex, the fourth lens has positive optical power, and the object side surface of the fourth lens is convex, the fifth lens has positive optical power, and the object side surface of the eighth lens is convex, and the image side surface of the eighth lens is concave; the spacer element group includes at least a first spacer element located between the first lens and the second lens and at least partially in contact with the image side surface of the first lens, a second spacer element located between the second lens and the third lens and at least partially in contact with the image side surface of the second lens, a third spacer element located between the third lens and the fourth lens and at least partially in contact with the image side surface of the third lens, a fourth lens located between the fourth lens and the fifth lens and at least partially in contact with the image side surface of the fourth lens, and a fifth lens located between the fourth lens and the fifth lens and at least partially in contact with the image side surface of the fourth lens. The lens group and the spacer element group are accommodated in a lens barrel, and the lens barrel includes an object side end face, an image side end face, an outer annular surface and an inner annular surface. Along the optical axis direction of the optical imaging device, the inner annular surface of the lens barrel is The surface is stepped; wherein, the focal length f of the optical imaging device, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy: -6.44≤(f1+f2) / f≤-5.03; the axial distance EP01 from the object side end face of the lens barrel to the object side face of the first spacing element, the axial distance EP12 from the image side face of the first spacing element to the object side face of the second spacing element, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy: -0.50≤EP01 / f1+EP12 / f2≤-0.40.

[0017] The optical imaging device of the present application uses eight lenses with optical power, and the first lens to the eighth lens are arranged in sequence and spaced apart. The first lens and the second lens with strong refractive power and negative optical power play the role of diffusing the incident light in the optical imaging device. By setting (f1+f2) / f within a reasonable range, it is beneficial for the optical imaging device to obtain a wide-angle effect and achieve better design performance and image quality. However, the first lens and the second lens are prone to quality problems during the processing and molding process, the lens uniformity is poor, and even problems such as weld marks and large yas may occur, affecting the imaging effect. The present application is beneficial to obtaining a lens structure design that is more suitable for the injection molding process, improving the machinability of the lens, effectively ensuring the uniformity of the lens, avoiding the generation of weld marks and yas, and suppressing the generation of stray light, thereby ensuring the actual imaging effect of the optical imaging device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 A schematic diagram showing some parameters of an optical imaging device according to any optional embodiment of the present invention;

[0020] Figure 2 A schematic structural diagram of an optical imaging device according to a first embodiment of the present invention is shown;

[0021] Figures 3 to 5 The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the optical imaging device of the first embodiment of the present invention are respectively shown;

[0022] Figure 6 A schematic structural diagram of an optical imaging device according to a second embodiment of the present invention is shown;

[0023] Figure 7 A schematic structural diagram of an optical imaging device according to a third embodiment of the present invention is shown;

[0024] Figure 8 A schematic structural diagram of an optical imaging device according to a fourth embodiment of the present invention is shown;

[0025] Figures 9 to 11 The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the optical imaging device in the fourth embodiment of the present invention are respectively shown;

[0026] Fig.12 A schematic structural diagram of an optical imaging device according to a fifth embodiment of the present invention is shown;

[0027] Fig.13A schematic structural diagram of an optical imaging device according to a sixth embodiment of the present invention is shown;

[0028] Fig.14 A schematic structural diagram of an optical imaging device according to a seventh embodiment of the present invention is shown;

[0029] Figures 15 to 17 The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the optical imaging device in the seventh embodiment of the present invention are respectively shown;

[0030] Fig.18 A schematic structural diagram of an optical imaging device according to an eighth embodiment of the present invention is shown;

[0031] Fig.19 A schematic structural diagram of an optical imaging device according to a ninth embodiment of the present invention is shown;

[0032] Figure 20 to Figure 22 The surface simulation curve diagram, MTF diagram and stray light diagram of an optical imaging device of the present invention under the condition of EP01 / f1+EP12 / f2=-0.435 are respectively shown;

[0033] Figure 23 to Figure 25 The surface simulation curve diagram, MTF diagram and stray light diagram of an optical imaging device in the prior art under the condition of EP01 / f1+EP12 / f2=-0.6 are respectively shown;

[0034] Figure 26 to Figure 28 The surface simulation curve graph, MTF graph and stray light graph of an optical imaging device in the prior art under the condition of EP01 / f1+EP12 / f2=-0.32 are respectively shown.

[0035] The above drawings include the following reference numerals:

[0036] P0, lens barrel; E1, first lens; S1, object side surface of first lens; S2, image side surface of first lens; E2, second lens; S3, object side surface of second lens; S4, image side surface of second lens; E3, third lens; S5, object side surface of third lens; S6, image side surface of third lens; E4, fourth lens; S7, object side surface of fourth lens; S8, image side surface of fourth lens; E5, the fifth lens; S9, the object-side surface of the fifth lens; S10, the image-side surface of the fifth lens; E6, the sixth lens; S11, the object-side surface of the sixth lens; S12, the image-side surface of the sixth lens; E7, the seventh lens; S13, the object-side surface of the seventh lens; S14, the image-side surface of the seventh lens; E8, the eighth lens; S15, the object-side surface of the eighth lens; S16, the image-side surface of the eighth lens; P1, the first spacing element; P2, the second spacing element; P3, the third spacing element; P4, the fourth spacing element; P5, the fifth spacing element; P6, the sixth spacing element; P7, the seventh spacing element; P7b, the seventh auxiliary spacing element; P8, the eighth spacing element. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0039] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0040] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0041] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0042] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens close to the object side is called the object side surface of the lens, and the surface of each lens close to the image side is called the image side surface of the lens. The judgment of the surface shape in the paraxial region can be based on the judgment method of the general knowledgeable person in this field, and the positive and negative R value (R refers to the radius of curvature of the paraxial region, usually refers to the R value on the lens database (lens data) in the optical software) is used to judge the concave and convex. For the object side, when the R value is positive, it is judged as a convex surface, and when the R value is negative, it is judged as a concave surface; for the image side, when the R value is positive, it is judged as a concave surface, and when the R value is negative, it is judged as a convex surface.

[0043] In order to solve the problem of poor processability of a front end lens of an optical imaging device in the prior art, the present invention provides an optical imaging device.

[0044] like Figures 1 to 22As shown, the optical imaging device has eight lenses with optical power, and the optical imaging device includes a lens group, a spacer element group and a lens barrel. From the object side to the image side of the optical imaging device, the lens group includes a first lens to an eighth lens arranged in sequence, wherein the first lens has negative optical power, the object side surface of the first lens is convex, and the image side surface of the first lens is concave, the second lens has negative optical power, and the image side surface of the second lens is concave, the third lens has positive optical power, and the object side surface of the third lens is convex, the fourth lens has positive optical power, and the object side surface of the fourth lens is convex, the fifth lens has positive optical power, and the object side surface of the eighth lens is convex, and the image side surface of the eighth lens is concave; the spacer element group at least includes a first spacer element located between the first lens and the second lens and at least partially in contact with the image side surface of the first lens, a second spacer element located between the second lens and the third lens and at least partially in contact with the image side surface of the second lens, a third spacer element located between the third lens and the fourth lens and at least partially in contact with the image side surface of the third lens, and a fourth spacer element located between the fourth lens and the fifth lens and at least partially in contact with the image side surface of the fourth lens to the eighth lens. The lens group and the spacer element group are accommodated in a lens barrel, and the lens barrel comprises an object-side end face, an image-side end face, an outer annular surface and an inner annular surface. Along the optical axis direction of the optical imaging device, the inner annular surface of the lens barrel is Step-shaped; wherein, the focal length f of the optical imaging device, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy: -6.44≤(f1+f2) / f≤-5.03; the axial distance EP01 from the object side end face of the lens barrel to the object side face of the first spacing element, the axial distance EP12 from the image side face of the first spacing element to the object side face of the second spacing element, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy: -0.50≤EP01 / f1+EP12 / f2≤-0.40.

[0045] The optical imaging device of the present application uses eight lenses with optical power, and the first lens to the eighth lens are arranged in sequence and spaced apart. The first lens and the second lens with strong refractive power and negative optical power play the role of diffusing the incident light in the optical imaging device. By setting (f1+f2) / f within a reasonable range, it is beneficial for the optical imaging device to obtain a wide-angle effect and achieve better design performance and image quality. However, the first lens and the second lens are prone to quality problems during the processing and molding process, the lens uniformity is poor, and even problems such as weld marks and large yas may occur, affecting the imaging effect. The present application is beneficial to obtaining a lens structure design that is more suitable for the injection molding process, improving the machinability of the lens, effectively ensuring the uniformity of the lens, avoiding the generation of weld marks and yas, and suppressing the generation of stray light, thereby ensuring the actual imaging effect of the optical imaging device.

[0046] Table 1 below provides a comparison between an optional embodiment of the present application and an optical imaging device in the prior art.

[0047]

[0048] Table 1

[0049] Device 2 and device 3 in Table 1 provide two optical imaging devices in the prior art. Figure 23 to Figure 25 As shown in the figure, under the condition of EP01 / f1+EP12 / f2=-0.600, the curve in the lens surface simulation curve is scattered, a single point is dropped, and the overlap between the red line and the blue line is not high. In other words, when the value of EP01 / f1+EP12 / f2 is too small, the difference between the inner and outer thickness of the lens is small, the rotational symmetry after processing is not good, the surface error is large, and the imaging clarity in both directions is seriously affected. Device 3 is as follows Figure 26 to Figure 28 As shown in the figure, under the condition of EP01 / f1+EP12 / f2=-0.320, the lens has a weld line and is prone to glare. That is to say, when the value of EP01 / f1+EP12 / f2 is too large, EP01 and EP12 are small, and the difference in thickness between the inside and outside of the lens is large, which easily produces a weld line, causing stray light problems and affecting the imaging effect.

[0050] The optical imaging device of the present application controls EP01 / f1+EP12 / f2 within a reasonable range, such as Figure 20 to Figure 22 As shown, the molding surface shape and weld mark problems can be balanced, and while the surface simulation curve is concentrated and the surface error is small, stray light caused by the weld mark is avoided, and better imaging effects can be achieved.

[0051] like Figures 1 to 22As shown, the maximum half field of view angle Semi-FOV of the optical imaging device, the outer diameter D0m of the image side end face of the lens barrel, and the on-axis distance TD from the object side of the first lens to the image side of the eighth lens satisfy the following conditions: 2.66≤TD*tan(Semi-FOV) / D0m≤11.95. When D0m is too large or TD is too small, the size of the lens is larger than the normal design, resulting in more material loss; when D0m is too small or TD is too large, the connection size of the structural part of the lens will have a large step difference, and the assembly processability of the optical imaging device cannot be ensured, thereby reducing the final imaging quality of the optical imaging device. Semi-FOV determines the shooting range of the optical imaging device. Under different shooting fields of view, by controlling TD*tan(Semi-FOV) / D0m within a reasonable range, the image quality, processability and cost can be balanced to the optimal proportion of the optical imaging device.

[0052] like Figures 1 to 22 As shown, the maximum half field angle Semi-FOV of the optical imaging device, the focal length f of the optical imaging device, and the on-axis distance L from the object side end face of the lens barrel to the image side end face of the lens barrel satisfy the following conditions: 0.41≤L / (f*tan(Semi-FOV))≤1.14. L is the maximum height of the lens barrel. When L is too small, the thickness and size of the lens in the optical imaging device will be compressed. Under the condition of ensuring the processability of the lens, when L / (f*tan(Semi-FOV)) is too large, the MTF performance will be severely reduced; when L is too large, the lens thickness is large, resulting in increased cost loss, and at the same time, the MTF cannot be highly improved. By controlling L / (f*tan(Semi-FOV)) within a reasonable range, the performance and cost of the optical imaging device can be controlled at an optimal ratio.

[0053] like Figures 1 to 22 As shown, the axial distance from the image side surface of the first lens to the object side surface of the second lens is the maximum axial distance of all two adjacent lenses, and the axial distance EP01 from the object side end surface of the lens barrel to the object side surface of the first spacing element and the axial distance T12 from the image side surface of the first lens to the object side surface of the second lens satisfy: 1.02≤EP01 / T12≤1.49. By controlling EP01 / T12 within a reasonable range, the uniformity and curvature of the first lens can be controlled by controlling the position of the first spacing element, avoiding appearance problems such as weld lines and flow marks when the first lens is formed.

[0054] like Figures 1 to 22As shown, the on-axis distance EP13 from the image side of the first spacer element to the object side of the third spacer element and the combined focal length f23 of the second lens and the third lens satisfy: -0.43≤EP13 / f23≤-0.13. The second lens and the third lens are the main lenses for controlling the performance of the optical imaging device. By controlling EP13 / f23 within a reasonable range, the influence of the first spacer element and the third spacer element on the vignetting position can be controlled, which is conducive to obtaining better MTF debugging performance and reducing the design sensitivity of the second lens and the third lens.

[0055] like Figures 1 to 22 As shown, the on-axis distance EP23 from the image side of the second spacer element to the object side of the third spacer element, the center thickness CT3 of the third lens, and the refractive index N3 of the third lens satisfy: 0.56≤EP23 / (CT3*N3)≤0.98. The third lens is the lens with the most concentrated light and also the lens with the greatest impact on the optical performance of the optical imaging device. By controlling EP23 / (CT3*N3) within a reasonable range, the vignetting position on both sides of the third lens, the center thickness of the third lens, and the refractive index of the third lens can be controlled, which is beneficial for the optical imaging device to obtain better MTF peak performance and effectively reduce the generation of ghost images.

[0056] like Figures 1 to 22 As shown, the on-axis distance EP34 from the image side surface of the third spacer element to the object side surface of the fourth spacer element, the radius of curvature R7 of the object side surface of the fourth lens, and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0.03≤EP34 / (R7+R8)≤0.56. The fourth lens is the lens position where light is initially separated in the optical imaging device. By controlling EP34 / (R7+R8) within a reasonable range, the vignetting position on both sides of the fourth lens can be controlled, effectively reducing the generation of stray light. At the same time, the curvature radius of the fourth lens can be controlled to avoid excessive field curvature differences between the internal and external fields of view of the optical imaging device (the field curvature difference is within 10um). In addition, stray light and performance can be balanced at the optimal point.

[0057] like Figures 1 to 22 As shown, the on-axis distance EP46 from the image side of the fourth spacer element to the object side of the sixth spacer element, the center thickness CT5 of the fifth lens, and the center thickness CT6 of the sixth lens satisfy: 0.95≤EP46 / (CT5+CT6)≤1.40. By controlling EP46 / (CT5+CT6) within a reasonable range, the center thickness of the fifth lens and the sixth lens, and the spacers on both sides of the fifth lens and the sixth lens can be used to eliminate the overall field of view chromatic aberration of the optical imaging device, while controlling the influence of the spacers on both sides of the fifth lens and the sixth lens on the vignetting position, which can effectively intercept non-required light and reduce the chromatic aberration of the edge field of view of the optical imaging device.

[0058] like Figures 1 to 22 As shown, the optical power of the sixth lens and the optical power of the seventh lens have opposite signs, and the effective focal length f6 of the sixth lens and the effective focal length f7 of the seventh lens satisfy: -2.04≤f6 / f7≤-0.67. By controlling f6 / f7 within a reasonable range, the focal lengths of the sixth lens and the seventh lens can be controlled, effectively balancing the macro performance and infinite distance performance of the optical imaging device, achieving a better macro performance and infinite distance performance ratio, and improving the overall performance upper limit of the optical imaging device.

[0059] like Figures 1 to 22 As shown, the inner diameter d6m of the image side surface of the sixth spacer element, the inner diameter d7m of the image side surface of the seventh spacer element, the curvature radius R13 of the object side surface of the seventh lens, and the curvature radius R15 of the object side surface of the eighth lens satisfy: 1.68≤d6m / R13+d7m / R15≤4.82. The seventh lens and the eighth lens play a major role in adjusting the macro performance, and adjusting the macro performance will affect the quality of edge aberrations. By controlling d6m / R13+d7m / R15 within a reasonable range and reasonably setting the apertures of the sixth spacer element and the seventh spacer element, aberrations can be effectively converged. In addition, the relationship between the aberration and macro performance of the optical imaging device is balanced, and the optical imaging device has good macro performance while also meeting aberration requirements.

[0060] like Figures 1 to 22 As shown, the inner diameter d6m of the image side surface of the sixth spacer element, the inner diameter d7m of the image side surface of the seventh spacer element, and the axial distance EP67 from the image side surface of the sixth spacer element to the object side surface of the seventh spacer element satisfy: 0.13≤(d7m-d6m) / EP67≤2.29. By controlling (d7m-d6m) / EP67 within a reasonable range, the relative positions of the sixth spacer element and the seventh spacer element can be effectively constrained, thereby more effectively converging aberrations.

[0061] like Figures 1 to 22 As shown, the inner diameter d0m of the image side end face of the lens barrel, the inner diameter d7m of the image side face of the seventh spacing element, and the effective focal length f8 of the eighth lens satisfy: -0.91≤(d0m-d7m) / f8≤1.30. The eighth lens is the last lens of the optical imaging device, and the effective focal length of the eighth lens has a large correlation with the stray light of the optical imaging device. By controlling (d0m-d7m) / f8 within a reasonable range, the difference between the inner diameter of the image side face of the lens barrel and the inner diameter of the image side face of the seventh spacing element can be controlled, and the smallest outer diameter of the image side end face of the lens barrel can be obtained while ensuring the process capability, while ensuring a smaller stray light effect.

[0062] Embodiment 1

[0063] like Figures 2 to 5 As shown, the optical imaging device of the first embodiment of the present application is described. Figure 2 A schematic structural diagram of the optical imaging device of the first embodiment is shown.

[0064] like Figure 2 As shown, the optical imaging device includes, from the object side to the image side, a first lens E1, a first spacing element P1, a second lens E2, a second spacing element P2, a third lens E3, an aperture STO, a third spacing element P3, a fourth lens E4, a fourth spacing element P4, a fifth lens E5, a fifth spacing element P5, a sixth lens E6, a sixth spacing element P6, a seventh lens E7, a seventh spacing element P7, a seventh auxiliary spacing element P7b, and an eighth lens E8.

[0065] The first lens E1 has negative focal power, the object side surface S1 of the first lens is convex, and the image side surface S2 of the first lens is concave. The second lens E2 has negative focal power, the object side surface S3 of the second lens is concave, and the image side surface S4 of the second lens is concave. The third lens E3 has positive focal power, the object side surface S5 of the third lens is convex, and the image side surface S6 of the third lens is convex. The fourth lens E4 has positive focal power, the object side surface S7 of the fourth lens is convex, and the image side surface S8 of the fourth lens is concave. The fifth lens E5 has positive focal power, the object side surface S9 of the fifth lens is concave, and the image side surface S10 of the fifth lens is convex. The sixth lens E6 has positive focal power, the object side surface S11 of the sixth lens is convex, and the image side surface S12 of the sixth lens is convex. The seventh lens E7 has negative focal power, the object side surface S13 of the seventh lens is concave, and the image side surface S14 of the seventh lens is concave. The eighth lens E8 has positive power, the object side surface S15 of the eighth lens is convex, and the image side surface S16 of the eighth lens is concave. The filter has an object side surface S17 of the filter and an image side surface S18 of the filter, and light from the object passes through each surface S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0066] Table 2 shows a basic structural parameter table of the optical imaging device of Example 1, wherein the units of the curvature radius, thickness / distance, effective radius and focal length are all millimeters (mm).

[0067]

[0068] Table 2

[0069] In Embodiment 1, the object side surface and the image side surface of any lens from the first lens E1 to the eighth lens E8 are both aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0070] (1);

[0071] Wherein, x is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 2 above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspherical surface. Table 3 below gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical mirror surface S1-S16 in Example 1.

[0072]

[0073] Table 3

[0074] Figure 3 The axial chromatic aberration curve of the optical imaging device of the first embodiment is shown, which indicates the deviation of the focusing point of light of different wavelengths after passing through the optical imaging device. Figure 4 The astigmatism curve of the optical imaging device of the first embodiment is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 5 The distortion curve of the optical imaging device of the first embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field of view angles.

[0075] according to Figures 3 to 5 It can be seen that the optical imaging device provided in the first embodiment can achieve good imaging quality.

[0076] Embodiment 2

[0077] like Figure 6 As shown, an optical imaging device according to the second embodiment of the present application is described, which differs from the first embodiment in that the distances and thicknesses between the spacer elements, lenses, lens barrel P0, etc. are different.

[0078] Figure 6 The schematic diagram of the structure of the optical imaging device of the second embodiment is shown. For the sake of brevity, some descriptions similar to those of the first embodiment are omitted. In this embodiment, the inner diameter of the seventh spacing element increases from the object side to the image side in a direction away from the optical axis, and the seventh auxiliary spacer can intercept stray light reflected from the inner diameter of the seventh spacing element toward the image side, thereby improving the cleanliness of the imaging.

[0079] Embodiment 3

[0080] like Figure 7 As shown, the optical imaging device of the third embodiment of the present application is described, which differs from the first embodiment in that the distances and thicknesses between the various spacing elements, lenses, lens barrel P0, etc. are different.

[0081] Figure 7The schematic diagram of the structure of the optical imaging device of the third embodiment shows that in this embodiment, the object side surface and the image side surface of the first spacer element are respectively attached to the structural parts of the first lens and the second lens, and the outer diameter of the first spacer element extends to the inner annular surface of the lens barrel, thereby increasing the area for supporting and intercepting stray light.

[0082] Embodiment 4

[0083] like Figures 8 to 11 As shown, the optical imaging device of embodiment 4 of the present application is described. Figure 8 A schematic structural diagram of an optical imaging device according to a fourth embodiment is shown.

[0084] like Figure 8 As shown, the optical imaging device includes, from the object side to the image side, the eighth spacing element P8, the first lens E1, the first spacing element P1, the second lens E2, the second spacing element P2, the third lens E3, the aperture STO, the third spacing element P3, the fourth lens E4, the fourth spacing element P4, the fifth lens E5, the fifth spacing element P5, the sixth lens E6, the sixth spacing element P6, the seventh lens E7, the seventh spacing element P7, and the eighth lens E8. The outer diameter of the optical imaging device gradually decreases from the object side to the image side, and the image side surface of the eighth lens rests on the lens barrel, that is, the optical imaging device of this embodiment is assembled from the image side to the object side, and the eighth spacing element is pressed on the object side surface of the first lens and rests on the inner annular surface of the lens barrel. The first lens E1 has a negative optical focal length, the object side surface S1 of the first lens is a convex surface, and the image side surface S2 of the first lens is a concave surface. The second lens E2 has a negative optical focal length, the object side surface S3 of the second lens is a convex surface, and the image side surface S4 of the second lens is a concave surface. The third lens E3 has positive focal power, the object side surface S5 of the third lens is convex, and the image side surface S6 of the third lens is concave. The fourth lens E4 has positive focal power, the object side surface S7 of the fourth lens is convex, and the image side surface S8 of the fourth lens is convex. The fifth lens E5 has positive focal power, the object side surface S9 of the fifth lens is convex, and the image side surface S10 of the fifth lens is concave. The sixth lens E6 has negative focal power, the object side surface S11 of the sixth lens is concave, and the image side surface S12 of the sixth lens is convex. The seventh lens E7 has positive focal power, the object side surface S13 of the seventh lens is convex, and the image side surface S14 of the seventh lens is convex. The eighth lens E8 has negative focal power, the object side surface S15 of the eighth lens is convex, and the image side surface S16 of the eighth lens is concave. The filter has an object-side surface S17 and an image-side surface S18 . Light from the object passes through the surfaces S1 to S18 in sequence and is finally imaged on an imaging surface S19 .

[0085] Table 4 shows a basic structural parameter table of the optical imaging device of Example 4, wherein the units of the curvature radius, thickness / distance, effective radius and focal length are all millimeters (mm).

[0086]

[0087] Table 4

[0088] Table 5 shows the high-order coefficients of the aspheric mirror surfaces that can be used in Example 4, wherein the aspheric surface shapes of the aspheric mirror surfaces can be defined by the formula (1) given in the above Example 1. In this embodiment, the object side surfaces and image side surfaces of the third lens to the eighth lens are all aspheric surfaces.

[0089]

[0090] Table 5

[0091] Fig. 9 The axial chromatic aberration curve of the optical imaging device of the fourth embodiment is shown, which indicates the deviation of the focusing point of light of different wavelengths after passing through the optical imaging device. Fig.10 The astigmatism curve of the optical imaging device of Example 4 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Fig.11 The distortion curve of the optical imaging device of the fourth embodiment is shown, which represents the distortion magnitude values ​​corresponding to different field of view angles.

[0092] according to Figures 9 to 11 It can be seen that the optical imaging device provided in the fourth embodiment can achieve good imaging quality.

[0093] Embodiment 5

[0094] like Fig.12 As shown, the optical imaging device of the fifth embodiment of the present application is described, which differs from the fourth embodiment in that the assembly sequence of the optical imaging device is different, and the distances and thicknesses between the various spacing elements, lenses, lens barrels, etc. are different.

[0095] Fig.12 The structure diagram of the optical imaging device of the fifth embodiment is shown. The optical imaging device of the present embodiment is assembled from the object side to the image side, and the object side surface of the first lens rests on the lens barrel without the need to provide an eighth spacing element.

[0096] Embodiment 6

[0097] like Fig.13 As shown, the optical imaging device of Example 6 of the present application is described, which differs from Example 4 in that the assembly sequence of the optical imaging device is different, and the distances and thicknesses between the various spacing elements, lenses, lens barrels, etc. are different.

[0098] Fig.13 The optical imaging device of the sixth embodiment is shown in FIG. The optical imaging device of the present embodiment is assembled from the object side to the image side, and the object side surface of the first lens rests on the lens barrel without the need to provide an eighth spacing element.

[0099] Embodiment 7

[0100] like Figures 14 to 17 As shown, the optical imaging device of embodiment 7 of the present application is described. Fig.14 A schematic structural diagram of an optical imaging device of Embodiment 7 is shown.

[0101] like Fig.14 As shown, the optical imaging device includes, from the object side to the image side, the first lens E1, the first spacing element P1, the second lens E2, the second spacing element P2, the third lens E3, the aperture STO, the third spacing element P3, the fourth lens E4, the fourth spacing element P4, the fifth lens E5, the fifth spacing element P5, the sixth lens E6, the sixth spacing element P6, the seventh lens E7, the seventh spacing element P7, and the eighth lens E8. In this embodiment, the outer diameter of the optical imaging device decreases first and then increases from the object side to the image side, that is, the lenses and spacing elements are assembled from the middle of the optical imaging device to both sides. In this embodiment, the fourth lens is used as the boundary, and the fourth lens is assembled to both sides in sequence.

[0102] The first lens E1 has negative focal power, the object side surface S1 of the first lens is convex, and the image side surface S2 of the first lens is concave. The second lens E2 has negative focal power, the object side surface S3 of the second lens is convex, and the image side surface S4 of the second lens is concave. The third lens E3 has positive focal power, the object side surface S5 of the third lens is convex, and the image side surface S6 of the third lens is convex. The fourth lens E4 has positive focal power, the object side surface S7 of the fourth lens is convex, and the image side surface S8 of the fourth lens is convex. The fifth lens E5 has positive focal power, the object side surface S9 of the fifth lens is convex, and the image side surface S10 of the fifth lens is convex. The sixth lens E6 has negative focal power, the object side surface S11 of the sixth lens is concave, and the image side surface S12 of the sixth lens is concave. The seventh lens E7 has positive focal power, the object side surface S13 of the seventh lens is concave, and the image side surface S14 of the seventh lens is convex. The eighth lens E8 has positive power, the object side surface S15 of the eighth lens is convex, and the image side surface S16 of the eighth lens is concave. The filter has an object side surface S17 of the filter and an image side surface S18 of the filter, and light from the object passes through each surface S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0103] Table 6 shows a basic structural parameter table of the optical imaging device of Example 7, wherein the units of the curvature radius, thickness / distance, effective radius and focal length are all millimeters (mm).

[0104]

[0105] Table 6

[0106] Table 7 shows the high-order coefficients of the aspheric mirror surfaces that can be used in Example 7, wherein the aspheric surface shapes of the aspheric mirror surfaces can be defined by the formula (1) given in the above Example 1. In this embodiment, the object side surfaces and image side surfaces of the third lens to the eighth lens are all aspheric surfaces.

[0107]

[0108] Table 7

[0109] Fig.15 The axial chromatic aberration curve of the optical imaging device of the seventh embodiment is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical imaging device. Fig.16 The astigmatism curve of the optical imaging device of Example 7 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Fig.17 The distortion curve of the optical imaging device of Example 7 is shown, which represents the distortion magnitude values ​​corresponding to different field angles.

[0110] according to Figures 15 to 17 It can be seen that the optical imaging device provided in the seventh embodiment can achieve good imaging quality.

[0111] Embodiment 8

[0112] like Fig.18 As shown, the optical imaging device of Example 8 of the present application is described, which differs from Example 7 in that the assembly sequence of the optical imaging device is different, and the distances and thicknesses between the various spacing elements, lenses, lens barrels, etc. are also different.

[0113] Fig.18 The structure diagram of the optical imaging device of Embodiment 8 is shown. In this embodiment, the object side of the first lens rests on the lens barrel, and the lens barrels are assembled sequentially from the first lens to the image side.

[0114] Embodiment 9

[0115] like Fig.19 As shown, the optical imaging device of Example 9 of the present application is described, which differs from Example 7 in that the assembly sequence of the optical imaging device is different, and the distances and thicknesses between the various spacing elements, lenses, lens barrels, etc. are also different.

[0116] Fig.19 The structure diagram of the optical imaging device of the ninth embodiment is shown. In this embodiment, the image side surface of the eighth lens rests on the lens barrel, and the lens barrel is assembled sequentially from the eighth lens to the object side.

[0117] In summary, Embodiments 1 to 9 respectively satisfy the relationship shown in Table 8.

[0118]

[0119] Table 8

[0120] Table 9 gives the maximum half field of view Semi-FOV of the optical imaging device of Examples 1 to 9, the on-axis distance TD from the object side of the first lens to the image side of the eighth lens, the effective focal length f of the optical imaging device, fno of the optical imaging device, the combined focal length f23 of the second lens and the third lens, and the effective focal lengths f1 to f8 of each lens.

[0121]

[0122] Table 9

[0123] Table 10 gives some structural parameters of the optical imaging devices of Examples 1 to 9, in units of mm.

[0124]

[0125] Table 10

[0126] The present application also provides an imaging device, whose electronic photosensitive element can be a photosensitive coupled device (CCD) or a complementary metal oxide semiconductor element (CMOS). The imaging device can be an independent imaging device such as a digital camera, or an imaging module integrated in a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging device described above.

[0127] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0128] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0129] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0130] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An optical imaging device, characterized in that: The optical imaging device has eight lenses with optical power, and the optical imaging device includes: A lens group, wherein the lens group comprises a first lens to an eighth lens arranged in sequence from the object side to the image side of the optical imaging device, wherein the first lens has negative optical power, the object side surface of the first lens is convex, and the image side surface of the first lens is concave, the second lens has negative optical power, and the image side surface of the second lens is concave, the third lens has positive optical power, and the object side surface of the third lens is convex, the fourth lens has positive optical power, and the object side surface of the fourth lens is convex, the fifth lens has positive optical power, the object side surface of the eighth lens is convex, and the image side surface of the eighth lens is concave; a spacer element group, wherein the spacer element group includes at least a first spacer element located between the first lens and the second lens and at least partially in contact with the image side surface of the first lens, a second spacer element located between the second lens and the third lens and at least partially in contact with the image side surface of the second lens, a third spacer element located between the third lens and the fourth lens and at least partially in contact with the image side surface of the third lens, a fourth spacer element located between the fourth lens and the fifth lens and at least partially in contact with the image side surface of the fourth lens, a fifth spacer element located between the fifth lens and the sixth lens and at least partially in contact with the image side surface of the fifth lens, a sixth spacer element located between the sixth lens and the seventh lens and at least partially in contact with the image side surface of the sixth lens, and a seventh spacer element located between the seventh lens and the eighth lens and at least partially in contact with the image side surface of the seventh lens; A lens barrel, wherein the lens group and the spacer element group are accommodated in the lens barrel, the lens barrel comprises an object side end surface, an image side end surface, an outer annular surface and an inner annular surface, and along the optical axis direction of the optical imaging device, the inner annular surface of the lens barrel is stepped; The focal length f of the optical imaging device, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy the following: -6.44≤(f1+f2) / f≤-5.03; The on-axis distance EP01 from the object side end face of the lens barrel to the object side face of the first spacing element, the on-axis distance EP12 from the image side face of the first spacing element to the object side face of the second spacing element, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy the following: -0.50≤EP01 / f1+EP12 / f2≤-0.

40.

2. The optical imaging device according to claim 1, characterized in that: The maximum half field of view Semi-FOV of the optical imaging device, the outer diameter D0m of the image side end surface of the lens barrel, and the axial distance TD from the object side surface of the first lens to the image side surface of the eighth lens satisfy the following: 2.66≤TD*tan(Semi-FOV) / D0m≤11.

95.

3. The optical imaging device according to claim 1, characterized in that: The maximum half field of view Semi-FOV of the optical imaging device, the focal length f of the optical imaging device, and the axial distance L from the object side end surface of the lens barrel to the image side end surface of the lens barrel satisfy the following: 0.41≤L / (f*tan(Semi-FOV))≤1.

14.

4. The optical imaging device according to claim 1, characterized in that: The on-axis distance from the image side surface of the first lens to the object side surface of the second lens is the maximum value of the on-axis distances between all two adjacent lenses, and the on-axis distance EP01 from the object side end surface of the lens barrel to the object side surface of the first spacing element and the on-axis distance T12 from the image side surface of the first lens to the object side surface of the second lens satisfy the following: 1.02≤EP01 / T12≤1.

49.

5. The optical imaging device according to claim 1, characterized in that: An axial distance EP13 from the image side surface of the first spacing element to the object side surface of the third spacing element and a combined focal length f23 of the second lens and the third lens satisfy the following: -0.43≤EP13 / f23≤-0.

13.

6. The optical imaging device according to claim 1, characterized in that: The on-axis distance EP23 from the image side surface of the second spacer element to the object side surface of the third spacer element, the center thickness CT3 of the third lens, and the refractive index N3 of the third lens satisfy: 0.56≤EP23 / (CT3*N3)≤0.

98.

7. The optical imaging device according to claim 1, characterized in that: The axial distance EP34 from the image side surface of the third spacing element to the object side surface of the fourth spacing element, the curvature radius R7 of the object side surface of the fourth lens, and the curvature radius R8 of the image side surface of the fourth lens satisfy: 0.03≤EP34 / (R7+R8)≤0.

56.

8. The optical imaging device according to claim 1, characterized in that: The on-axis distance EP46 from the image side surface of the fourth spacer element to the object side surface of the sixth spacer element, the center thickness CT5 of the fifth lens, and the center thickness CT6 of the sixth lens satisfy the following: 0.95≤EP46 / (CT5+CT6)≤1.

40.

9. The optical imaging device according to claim 1, characterized in that: The optical power of the sixth lens and the optical power of the seventh lens have opposite signs, and the effective focal length f6 of the sixth lens and the effective focal length f7 of the seventh lens satisfy the following: -2.04≤f6 / f7≤-0.

67.

10. The optical imaging device according to claim 1, characterized in that: The inner diameter d6m of the image side surface of the sixth spacing element, the inner diameter d7m of the image side surface of the seventh spacing element, the curvature radius R13 of the object side surface of the seventh lens, and the curvature radius R15 of the object side surface of the eighth lens satisfy: 1.68≤d6m / R13+d7m / R15≤4.

82.

11. The optical imaging device according to any one of claims 1 to 10, characterized in that: An inner diameter d6m of the image side surface of the sixth spacer element, an inner diameter d7m of the image side surface of the seventh spacer element, and an axial distance EP67 from the image side surface of the sixth spacer element to the object side surface of the seventh spacer element satisfy: 0.13≤(d7m-d6m) / EP67≤2.

29.

12. The optical imaging device according to any one of claims 1 to 10, characterized in that: The inner diameter d0m of the image side end surface of the lens barrel, the inner diameter d7m of the image side surface of the seventh spacing element, and the effective focal length f8 of the eighth lens satisfy the following: -0.91≤(d0m-d7m) / f8≤1.30.

Images