A spherical ultra-wide-angle lens

Abstract

A spherical ultra-wide-angle lens comprises, in order along the light incident direction, a first single lens, a second single lens, a third single lens, a fourth single lens, a first cemented group, a fifth single lens, a sixth single lens, a seventh single lens, a second cemented group, and an eighth single lens; the object side surface and image side surface of the first single lens are convex and concave, respectively; the object side surface and image side surface of the second single lens are convex and concave, respectively; the object side surface and image side surface of the third single lens are both convex; the object side surface and image side surface of the fourth single lens are respectively convex and concave; the object side surface and image side surface of the first cemented group are concave; the object side surface and image side surface of the fifth single lens are convex; the object side surface and image side surface of the sixth single lens are convex; the object side surface and image side surface of the seventh single lens are concave; the object side surface and image side surface of the second cemented group are convex; and the object side surface and image side surface of the eighth single lens are respectively concave and convex. The present invention has the advantages of low cost, ultra-wide angle, compact structure, and adopting an optically passive athermal design.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular to a spherical ultra-wide-angle lens. Background Art

[0002] Optical imaging systems play an increasingly important role in information acquisition. In the field of airborne imaging, optical systems use optical lenses to capture optical information about the environment or targets, then display the images on back-end equipment to provide information. Therefore, the performance and image quality of optical lenses are key evaluation indicators for optical imaging systems. The field of view of an optical lens determines the range of scenes that can be imaged. To capture a wider range of information, ultra-wide-angle optical lenses are often used. However, ultra-wide-angle lenses introduce significant image distortion, which causes the optical image to distort and differ significantly from the actual image. To achieve optimal imaging, the optical system's luminous flux should be as high as possible and aberrations as low as possible. The imaging plane illumination formula shows that the luminous flux of an optical system is proportional to the square of the relative aperture. To increase the optical system's luminous flux, the relative aperture should be as large as possible, and the corresponding F-number should be as small as possible. However, the smaller the F-number, the more difficult it is to correct for aberrations in the optical system. Aspherical lenses are effective in correcting aberrations, but they are expensive. Considering cost factors and structural limitations, optical lenses should be compact and spherical lenses should be used whenever possible. In order to better adapt to the field of airborne imaging, the optical lens should be able to achieve a heat-free design simply by adjusting the lens material and structure, so that the optical lens can adapt to a wider temperature range.

[0003] Patent application number CN11723398.B discloses an ultra-wide-angle, low-distortion optical lens, which effectively controls distortion and aberration by optimizing and changing the surface parameters of the lens. However, the extensive use of aspherical lenses makes the optical system expensive, which is not conducive to large-scale promotion.

[0004] Patent application number CN117518402.A discloses a spherical ultra-wide-angle optical imaging system with a field of view of 102°. All lenses are spherical and low-cost. However, the F number is 3.5, the luminous flux is small, and it is difficult to ensure the imaging quality under insufficient light conditions. Summary of the Invention

[0005] The present invention provides a spherical ultra-wide-angle lens to solve the technical problems mentioned in the background technology.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] The present invention provides a spherical ultra-wide-angle lens, which comprises, in order from the object side to the imaging surface along the optical axis:

[0008] a first single lens having negative optical power, wherein the object-side surface of the first single lens is convex and the image-side surface of the first single lens is concave;

[0009] a second single lens having negative optical power, wherein the object-side surface of the second single lens is convex and the image-side surface of the second single lens is concave;

[0010] a third single lens having positive refractive power, wherein the object-side surface of the third single lens is convex, and the image-side surface of the third single lens is convex;

[0011] a fourth single lens having positive refractive power, wherein the object-side surface of the fourth single lens is convex and the image-side surface of the fourth single lens is concave;

[0012] a first cemented group having negative optical power, wherein the object-side surface of the first cemented group is a concave surface, and the image-side surface of the first cemented group is a concave surface;

[0013] a fifth single lens having positive refractive power, wherein the object-side surface of the fifth single lens is convex, and the image-side surface of the fifth single lens is convex;

[0014] a sixth single lens having positive refractive power, wherein the object-side surface of the sixth single lens is convex, and the image-side surface of the sixth single lens is convex;

[0015] a seventh single lens having negative optical power, wherein the object-side surface of the seventh single lens is concave, and the image-side surface of the seventh single lens is concave;

[0016] a second cemented group having positive optical power, wherein the object-side surface of the second cemented group is a convex surface, and the image-side surface of the second cemented group is a convex surface;

[0017] An eighth single lens having negative optical power, wherein the object-side surface of the eighth single lens is concave and the image-side surface of the eighth single lens is convex.

[0018] Furthermore, the spherical ultra-wide-angle lens further includes a stop, which is disposed between the fifth single lens and the sixth single lens;

[0019] Or, the aperture is arranged on the surface of one of the optical elements in the first single lens, the second single lens, the third single lens, the fourth single lens, the first cemented group, the fifth single lens, the sixth single lens, the seventh single lens, the second cemented group, and the eighth single lens.

[0020] Furthermore, the distance between the fifth single lens and the aperture is between 0.3 and 0.8 mm, and the distance between the aperture and the sixth single lens is between 0.1 and 0.3 mm.

[0021] Furthermore, the spherical ultra-wide-angle lens further includes a filter, a sensor protection window, and an imaging surface sequentially arranged along the optical axis;

[0022] The filter is disposed on one side of the image side of the eighth singlet lens for filtering light; the sensor protection window is used to protect the chip inside the optical system; the imaging surface is used for imaging.

[0023] Furthermore, the refractive index Nd of the materials of the filter and the sensor protection window satisfies 1.5 < Nd < 1.6, and the Abbe number Vd satisfies 62 < Vd < 64;

[0024] The distance between the filter and the eighth singlet lens is between 0.2 and 0.6 mm, the distance between the filter and the sensor protection window is between 0.5 and 2 mm, and the distance between the sensor protection window and the imaging surface is between 0.3 and 0.8 mm.

[0025] Furthermore, the first cemented group includes a meniscus negative lens and a meniscus positive lens;

[0026] The object side of the meniscus negative lens is concave, and the image side of the meniscus negative lens is concave; the refractive index Nd of the material of the meniscus negative lens satisfies 1.7 < Nd < 1.8, and the Abbe number Vd satisfies 33 < Vd < 35;

[0027] The object side of the meniscus positive lens is convex, and the image side of the meniscus positive lens is concave; the object side of the meniscus positive lens is bonded to the image side of the meniscus negative lens; the refractive index Nd of the material of the meniscus positive lens satisfies 1.4 < Nd < 1.5, and the Abbe number Vd satisfies 33 < Vd < 67.

[0028] Furthermore, the second cemented group includes a biconvex positive lens and a meniscus concave lens;

[0029] The object side of the biconvex positive lens is convex, and the image side of the biconvex positive lens is convex; the refractive index Nd of the material of the biconvex positive lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 57 < Vd < 59;

[0030] The object side of the meniscus concave lens is concave, and the image side of the meniscus concave lens is convex; the object side of the meniscus concave lens is concave and is bonded to the image side of the biconvex positive lens, and the refractive index Nd of the material of the meniscus concave lens satisfies 1.9 < Nd < 2.0, and the Abbe number Vd satisfies 30 < Vd < 32.

[0031] Furthermore, the optical power of the first singlet lens is between -0.02 and -0.06 mm -1 ;

[0032] and / or, the optical power of the second singlet lens is between -0.02 and -0.06 mm -1 ;

[0033] And / or, the optical power of the third single lens is 0.02~0.04mm -1 between;

[0034] And / or, the optical power of the fourth single lens is 0.02~0.04mm -1 between;

[0035] And / or, the optical power of the fifth single lens is 0.07~0.09mm -1 between;

[0036] And / or, the optical power of the sixth single lens is 0.06~0.08mm -1 between;

[0037] And / or, the optical power of the seventh single lens is between -0.04 and -0.06 mm. -1 between;

[0038] And / or, the optical power of the eighth single lens is between -0.04 and 0.06 mm. -1 between.

[0039] Furthermore, the optical elements in the spherical ultra-wide-angle lens satisfy at least one or more of the following inequalities:

[0040] The effective focal length f11 of the first single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -4 < f11 / f < -2; the effective focal length f12 of the second single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -4 < f12 / f < -1; the effective focal length f13 of the third single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f13 / f < 4; the effective focal length f14 of the fourth single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f14 / f < 4; the object-side lens effective focal length f151 of the first cemented group and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -0.2 < f151 / f < -2; the image-side lens effective focal length f152 of the first cemented group and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f152 / f < 4; the effective focal length f16 of the fifth single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f16 / f < 4; the effective focal length f31 of the sixth single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f31 / f < 4; the effective focal length f32 of the seventh single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -4 < f32 / f < -1; the object-side lens effective focal length f331 of the second cemented group and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 0.1 < f331 / f < 2; the image-side lens effective focal length f332 of the second cemented group and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -2 < f331 / f < -0.1; the effective focal length f34 of the eighth single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -4 < f34 / f < -1.

[0041] Further, the distance intervals between the respective optical elements within the spherical ultra-wide-angle lens satisfy at least one or more of the following distance intervals;

[0042] The distance between the first single lens and the second single lens is between 6 and 8 mm, the distance between the second single lens and the third single lens is between 3 and 5 mm, the distance between the third single lens and the fourth single lens is between 0.1 and 0.2 mm, the distance between the fourth single lens and the first cemented group is between 1 and 3 mm, and the distance between the first cemented group and the fifth single lens is between 0.05 and 0.2 mm;

[0043] The distance between the sixth single lens and the seventh single lens is between 0.1 and 0.2 mm, the distance between the seventh single lens and the second cemented group is between 0.7 and 0.9 mm, and the distance between the second cemented group and the eighth single lens is between 3 and 5 mm.

[0044] Furthermore, the refractive index and Abbe number of the materials used for each optical element in the spherical ultra-wide-angle lens satisfy at least one or more of the following inequalities;

[0045] The refractive index Nd of the material of the first singlet lens satisfies 1.7 < Nd < 1.8, and the Abbe number Vd satisfies 49 < Vd < 51; the refractive index Nd of the material of the second singlet lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 55 < Vd < 57; the refractive index Nd of the material of the third singlet lens satisfies 1.8 < Nd < 1.9, and the Abbe number Vd satisfies 39 < Vd < 41; the refractive index Nd of the material of the fourth singlet lens satisfies 1.8 < Nd < 1.9, and the Abbe number Vd satisfies 38 < Vd < 40; the refractive index Nd of the material of the fifth singlet lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 54 < Vd < 56; the refractive index Nd of the material of the sixth singlet lens satisfies 1.7 < Nd < 1.8, and the Abbe number Vd satisfies 53 < Vd < 55; the refractive index Nd of the material of the seventh singlet lens satisfies 1.5 < Nd < 1.6, and the Abbe number Vd satisfies 63 < Vd < 65; the refractive index Nd of the material of the eighth singlet lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 57 < Vd < 59.

[0046] Advantages of the present invention:

[0047] 1. The first lens (i.e., the first singlet lens) of the present invention uses a straw hat structure to collect wide-angle light, and the second lens (i.e., the second singlet lens) uses a similar straw hat structure for distortion correction. The symmetric structure has a good effect on aberration correction, and at the same time ensures the compactness of the optical system structure, so that the observation aperture of the optical system after installing the present invention will not be too large.

[0048] 2. All lenses in the present invention use glass spherical lenses, which are inexpensive, have good processability, and high stability, greatly reducing the processing cost of the spherical ultra-wide-angle lens.

[0049] 3. The structure of the present invention is compact, and the assembly and debugging are simple. Through the form of using all-glass spherical optical elements, material combination and reasonable distribution of optical power, an optical athermalization design is achieved, so that the optical system maintains clear imaging within the temperature range of -55°C to +70°C, greatly expanding the applicable range of the spherical ultra-wide-angle lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a schematic structural diagram of the present invention;

[0051] Figure 2 is a schematic diagram of the distribution of each mirror surface of the spherical ultra-wide-angle lens in the present invention;

[0052] Figure 3This is a graph showing the MTF evaluation results of the spherical ultra-wide-angle lens at room temperature (20°C) in a specific embodiment of the present invention;

[0053] Figure 4 This is a graph showing the MTF evaluation results at low temperature (-55°C) for the spherical ultra-wide-angle lens in a specific embodiment of the present invention;

[0054] Figure 5 This is a diagram showing the MTF evaluation results at high temperature (70°C) of the spherical ultra-wide-angle lens in a specific embodiment of the present invention;

[0055] Figure 6 This is a diagram showing the distortion evaluation results of a spherical ultra-wide-angle lens in a specific embodiment of the present invention;

[0056] Figure 7 This is a diagram showing the relative illumination evaluation results of the spherical ultra-wide-angle lens in a specific embodiment of the present invention.

[0057] Description of reference numerals:

[0058] 1. Front group; 2. Aperture; 3. Rear group; 4. Filter; 5. Sensor protection window; 6. Imaging surface; 11. First single lens; 12. Second single lens; 13. Third single lens; 14. Fourth single lens; 15. First cemented group; 16. Fifth single lens; 31. Sixth single lens; 32. Seventh single lens; 33. Second cemented group; 34. Eighth single lens; 151. Meniscus negative lens; 152. Meniscus positive lens; 331. Biconvex positive lens; 332. Meniscus concave lens;

[0059] S1, the object side surface of the first single lens; S2, the image side surface of the first single lens; S3, the object side surface of the second single lens; S4, the image side surface of the second single lens; S5, the object side surface of the third single lens; S6, the image side surface of the third single lens; S7, the object side surface of the fourth single lens; S8, the image side surface of the fourth single lens; S9, the object side surface of the negative meniscus lens; S10, the image side surface of the negative meniscus lens; S11, the object side surface of the positive meniscus lens; S12, the image side surface of the positive meniscus lens; S13, the object side surface of the fifth single lens; S14, the image side surface of the fifth single lens; S15, the object side surface of the sixth single lens; S16, the image side surface of the sixth single lens; S17, the object side surface of the seventh single lens; S18, the image side surface of the seventh single lens; S19, the object side surface of the biconvex positive lens; S20, the image side surface of the biconvex positive lens; S21, the object side surface of the concave meniscus lens; S22, the image side surface of the concave meniscus lens; S23, the object side surface of the eighth single lens; S24, the image side surface of the eighth single lens. DETAILED DESCRIPTION

[0060] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many other forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0063] It should also be noted that, in the embodiments of the present application, the same figure mark represents the same component or the same part. For the same parts in the embodiments of the present application, the figure may only mark one of the parts or components as an example. It should be understood that the figure mark also applies to other identical parts or components.

[0064] Reference Figure 1 and Figure 2 , an embodiment of the present application provides a spherical ultra-wide-angle lens, which includes a front group 1 and a rear group 3 in sequence from the object side to the imaging surface along the optical axis;

[0065] The front group 1 includes the following components along the optical axis from the object side to the imaging surface:

[0066] a first single lens 11 having negative optical power, wherein the object-side surface S1 of the first single lens is convex, and the image-side surface S2 of the first single lens is concave;

[0067] a second single lens 12 having negative optical power, wherein the object-side surface S3 of the second single lens is convex, and the image-side surface S4 of the second single lens is concave;

[0068] a third single lens 13 having positive refractive power, wherein the object-side surface S5 of the third single lens is convex, and the image-side surface S6 of the third single lens is convex;

[0069] a fourth single lens 14 having positive refractive power, wherein the object-side surface S7 of the fourth single lens is convex, and the image-side surface S8 of the fourth single lens is concave;

[0070] a first cemented group 15 having negative optical power, wherein the object-side surface of the first cemented group 15 is a concave surface, and the image-side surface of the first cemented group 15 is a concave surface;

[0071] a fifth single lens 16 having positive refractive power, wherein the object-side surface S13 of the fifth single lens is convex, and the image-side surface S14 of the fifth single lens is convex;

[0072] The rear group 3 includes the following components along the optical axis from the object side to the imaging surface:

[0073] a sixth single lens 31 having positive refractive power, wherein the object-side surface S15 of the sixth single lens is convex, and the image-side surface S16 of the sixth single lens is convex;

[0074] A seventh single lens 32 having negative optical power, wherein the object-side surface S17 of the seventh single lens is concave, and the image-side surface S18 of the seventh single lens is concave;

[0075] a second cemented group 33 having positive optical power, wherein the object-side surface of the second cemented group 33 is a convex surface, and the image-side surface of the second cemented group 33 is a convex surface;

[0076] The eighth single lens 34 has a negative optical power, wherein the object-side surface S23 of the eighth single lens is a concave surface, and the image-side surface S24 of the eighth single lens is a convex surface.

[0077] Reference Figure 6 and Figure 7 In this embodiment, the spherical ultra-wide-angle lens is a fixed-focus imaging lens with a focal length of 10.3, an F number (aperture number) of 2.1, a field of view of 103.8°, an operating band of 400nm~700nm, and a total optical length of 47.5mm. The distortion is 15.09%, as shown in the following figure. Figure 6 As shown; the relative illumination of the edge field is 31%, as shown Figure 7 shown.

[0078] The first lens (i.e., the first single lens 11) of the present invention adopts a straw hat structure to collect wide-angle light, and the second lens (i.e., the second single lens 12) uses a similar straw hat structure to correct distortion. The symmetrical structure has a good aberration correction effect, while ensuring the compactness of the optical system structure, so that the observation aperture of the optical system after installing the present invention will not be too large.

[0079] In some embodiments, the spherical ultra-wide-angle lens further includes a stop 2, which is disposed between the fifth single lens 16 and the sixth single lens 31;

[0080] Alternatively, the aperture 2 is arranged on the surface of one of the optical elements within the first single lens 11, the second single lens 12, the third single lens 13, the fourth single lens 14, the first cemented group 15, the fifth single lens 16, the sixth single lens 31, the seventh single lens 32, the second cemented group 33, and the eighth single lens 34.

[0081] In some embodiments, the distance between the fifth single lens 16 and the aperture 2 is between 0.3 and 0.8 mm. Preferably, the distance between the fifth single lens 16 and the aperture 2 is 0.557 mm.

[0082] The distance between the aperture 2 and the sixth single lens 31 is between 0.1 and 0.3 mm. Preferably, the distance between the aperture 2 and the sixth single lens 31 is 0.2 mm.

[0083] In some embodiments, the spherical ultra-wide-angle lens further includes a filter 4, a sensor protection window 5, and an imaging surface 6 sequentially arranged along the optical axis;

[0084] The filter 4 is arranged on the side of the image side S24 of the eighth single lens and is used for filtering light; the sensor protection window 5 is used for protecting the chip inside the optical system; and the imaging surface 6 is used for imaging.

[0085] In some embodiments, the filter 4 and the sensor protection window 5 are made of optical glass HK9L;

[0086] In some embodiments, the distance between the filter 4 and the eighth single lens 34 is between 0.2 and 0.6 mm. Preferably, the distance between the filter 4 and the eighth single lens 34 is 0.429 mm.

[0087] In some embodiments, the distance between the filter 4 and the sensor protection window 5 is between 0.5 and 2 mm. Preferably, the distance between the filter 4 and the sensor protection window 5 is 1.029 mm.

[0088] In some embodiments, the distance between the sensor protection window 5 and the imaging surface 6 is between 0.3 and 0.8 mm. Preferably, the distance between the sensor protection window 5 and the imaging surface 6 is 0.505 mm.

[0089] In some embodiments, the first cemented group 15 includes a negative meniscus lens 151 and a positive meniscus lens 152;

[0090] The object side S9 of the meniscus negative lens is concave, and the image side S10 of the meniscus negative lens is concave; the material of the meniscus negative lens 151 is optical glass HTF8;

[0091] The object side S11 of the meniscus positive lens is convex, and the image side S12 of the meniscus positive lens is concave; the object side S11 of the meniscus positive lens is bonded to the image side S10 of the meniscus negative lens; the material of the meniscus positive lens 152 is optical glass HQK1.

[0092] In some embodiments, the second cemented group 33 includes a biconvex positive lens 331 and a meniscus concave lens 332;

[0093] The object side S19 of the biconvex positive lens is convex, and the image side S20 of the biconvex positive lens is convex. The material of the biconvex positive lens 331 is optical glass HLAK50A.

[0094] The object side S21 of the meniscus concave lens is concave, and the image side S22 of the meniscus concave lens is convex; the object side S21 of the meniscus concave lens is bonded to the image side S20 of the biconvex positive lens, and the material of the meniscus concave lens 332 is optical glass HZLAF75B.

[0095] In some embodiments, the optical power of the first single lens 11 is between -0.02 and -0.06 mm. -1 Preferably, the optical power of the first single lens 11 is -0.032mm -1 ;

[0096] In some embodiments, the optical power of the second single lens 12 is between -0.02 and -0.06 mm. -1 Preferably, the optical power of the second single lens 12 is -0.047 mm -1 ;

[0097] In some embodiments, the optical power of the third single lens 13 is between 0.02 and 0.04 mm. -1 Preferably, the focal length of the third single lens 13 is 0.034 mm. -1 ;

[0098] In some embodiments, the optical power of the fourth single lens 14 is between 0.02 and 0.04 mm. -1 Preferably, the optical power of the fourth single lens 14 is 0.034 mm -1 ;

[0099] In some embodiments, the optical power of the fifth single lens 16 is between 0.07 and 0.09 mm. -1 Preferably, the optical power of the fifth single lens 16 is 0.082 mm. -1 ;

[0100] In some embodiments, the optical power of the sixth single lens 31 is between 0.06 and 0.08 mm. -1Preferably, the optical power of the sixth single lens 31 is 0.072 mm -1 ;

[0101] In some embodiments, the optical power of the seventh single lens 32 is between -0.04 and -0.06 mm. -1 Preferably, the optical power of the seventh single lens 32 is -0.055mm -1 ;

[0102] In some embodiments, the optical power of the eighth single lens 34 is between -0.04 and 0.06 mm. -1 Preferably, the optical power of the eighth single lens 34 is -0.05mm -1 .

[0103] The preferred optical powers of the above lenses were obtained through a large number of comparative experiments. This data, combined with the selection of materials and shapes for each lens (i.e., the materials and shapes of each lens described below), enables the present invention to achieve an optical athermal design, allowing the optical system to maintain clear imaging within a temperature range of -55°C to +70°C, greatly expanding the applicability of spherical ultra-wide-angle lenses.

[0104] In some embodiments, the distance between the first single lens 11 and the second single lens 12 is between 6 and 8 mm. Preferably, the distance between the first single lens 11 and the second single lens 12 is 7.5 mm.

[0105] In some embodiments, the distance between the second single lens 12 and the third single lens 13 is between 3 and 5 mm. Preferably, the distance between the second single lens 12 and the third single lens 13 is 3.986 mm.

[0106] In some embodiments, the distance between the third single lens 13 and the fourth single lens 14 is between 0.1 and 0.2 mm. Preferably, the distance between the third single lens 13 and the fourth single lens 14 is 0.122 mm.

[0107] In some embodiments, the distance between the fourth single lens 14 and the first cemented group 15 is between 1 and 3 mm. Preferably, the distance between the fourth single lens 14 and the first cemented group 15 is 2.672 mm.

[0108] In some embodiments, the distance between the first cemented group 15 and the fifth single lens 16 is between 0.05 and 0.2 mm. Preferably, the distance between the first cemented group 15 and the fifth single lens 16 is 0.1 mm.

[0109] In some embodiments, the distance between the sixth single lens 31 and the seventh single lens 32 is between 0.1 and 0.2 mm. Preferably, the distance between the sixth single lens 31 and the seventh single lens 32 is 0.11 mm.

[0110] In some embodiments, the distance between the seventh single lens 32 and the second cemented group 33 is between 0.7 and 0.9 mm. Preferably, the distance between the seventh single lens 32 and the second cemented group 33 is 0.827 mm.

[0111] In some embodiments, the distance between the second cemented group 33 and the eighth single lens 34 is between 3 and 5 mm. Preferably, the distance between the second cemented group 33 and the eighth single lens 34 is 4.373 mm.

[0112] The preferred distances between the above lenses were obtained through a large number of experiments. By comparing multiple sets of data, it was found that this set of data (i.e., the preferred distances between the above lenses) can make the structure of the present invention more compact while ensuring that the optical system after installing the present invention has the best clear imaging effect, while also reducing the observation aperture of the optical system after installing the present invention.

[0113] In some embodiments, the optical elements in the spherical ultra-wide-angle lens satisfy at least one or more of the following inequalities:

[0114] The effective focal length f11 of the first single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: <f11 / f<-2;

[0115] The effective focal length f12 of the second single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: <f12 / f<-1;

[0116] The effective focal length f13 of the third single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: <f13 / f<4;

[0117] The effective focal length f14 of the fourth single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: <f14 / f<4;

[0118] The effective focal length f151 of the object lens of the first cemented group and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -0.2 <f151 / f<-2;

[0119] The effective focal length f152 of the image side lens of the first cemented group and the effective focal length f of the spherical ultra-wide-angle lens satisfy: <f152 / f<4;

[0120] The effective focal length f16 of the fifth single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f16 / f < 4;

[0121] The effective focal length f31 of the sixth single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f31 / f < 4;

[0122] The effective focal length f32 of the seventh single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -4 < f32 / f < -1;

[0123] The effective focal length f331 of the object-side lens of the second cemented group and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 0.1 < f331 / f < 2;

[0124] The effective focal length f332 of the image-side lens of the second cemented group and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -2 < f331 / f < -0.1;

[0125] The effective focal length f34 of the eighth single lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -4 < f34 / f < -1.

[0126] In some embodiments, the refractive index and Abbe number of the materials used for each optical element in the spherical ultra-wide-angle lens satisfy at least one or more of the following inequalities;

[0127] The refractive index Nd of the material of the first single lens satisfies 1.7 < Nd < 1.8, and the Abbe number Vd satisfies 49 < Vd < 51;

[0128] The refractive index Nd of the material of the second single lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 55 < Vd < 57;

[0129] The refractive index Nd of the material of the third single lens satisfies 1.8 < Nd < 1.9, and the Abbe number Vd satisfies 39 < Vd < 41;

[0130] The refractive index Nd of the material of the fourth single lens satisfies 1.8 < Nd < 1.9, and the Abbe number Vd satisfies 38 < Vd < 40;

[0131] The refractive index Nd of the material of the fifth single lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 54 < Vd < 56;

[0132] The refractive index Nd of the material of the sixth single lens satisfies 1.7 < Nd < 1.8, and the Abbe number Vd satisfies 53 < Vd < 55;

[0133] The refractive index Nd of the material of the seventh single lens satisfies 1.5 < Nd < 1.6, and the Abbe number Vd satisfies 63 < Vd < 65;

[0134] The refractive index Nd of the material of the eighth single lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 57 < Vd < 59.

[0135] In some embodiments, the material of the first single lens 11 is optical glass HLAK3; the material of the second single lens 12 is optical glass HZK10L; the material of the third single lens 13 is optical glass HZLAF73; the material of the fourth single lens 14 is optical glass HZLAF68N; the material of the fifth single lens 16 is optical glass HLAK10; the material of the sixth single lens 31 is optical glass HLAK52; the material of the seventh single lens 32 is optical glass HK9LA; the material of the eighth single lens 34 is optical glass HLAK50A.

[0136] The data of each optical element in the spherical ultra-wide-angle lens provided in this embodiment are shown in Table 1. The data shown in Table 1 are only examples of the data in the embodiments of the present invention and cannot be used to limit the protection scope of the present invention;

[0137] Table 1: Data table of each optical element in the spherical ultra-wide-angle lens

[0138]

[0139] The spherical ultra-wide-angle lens provided by the present invention can achieve clear imaging in an ultra-wide temperature use environment of -55°C to +70°C, such as Figure 3 , Figure 4 , Figure 5 shown. It should be noted that the MTF (Modulation Transfer Function) evaluation curve graph characterizes the relative change of the modulation degree with the spatial frequency (lines per millimeter, unit: lp / mm) during the imaging process, and is often used to evaluate the resolution of the imaging lens. Figures 3 to 5 is the MTF evaluation result graph at different temperatures; the abscissa in the graph represents the spatial frequency, and the ordinate in the graph represents the modulation degree (modulus of the optical transfer function).

[0140] The structure of the present invention is compact, and the assembly and debugging are simple. Through the form of using all-spherical glass optical elements, material combination and reasonable distribution of the optical power, an optical athermalization design is achieved, enabling the optical system to maintain clear imaging within the temperature range of -55°C to +70°C, greatly expanding the applicable range of the spherical ultra-wide-angle lens.

[0141] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A spherical ultra-wide-angle lens, characterized in that: From the object side to the imaging surface along the optical axis, it consists of a first single lens, a second single lens, a third single lens, a fourth single lens, a first cemented doublet, a fifth single lens, an aperture stop, a sixth single lens, a seventh single lens, a second cemented doublet, and an eighth single lens in sequence: A first single lens with negative focal power, the object side surface of the first single lens is convex, and the image side surface of the first single lens is concave; A second single lens with negative focal power, the object side surface of the second single lens is convex, and the image side surface of the second single lens is concave; A third single lens with positive focal power, the object side surface of the third single lens is convex, and the image side surface of the third single lens is convex; A fourth single lens with positive focal power, the object side surface of the fourth single lens is convex, and the image side surface of the fourth single lens is concave; A first cemented doublet with negative focal power, which consists of a meniscus negative lens and a meniscus positive lens, the object side surface of the first cemented doublet is concave, and the image side surface of the first cemented doublet is concave; A fifth single lens with positive focal power, the object side surface of the fifth single lens is convex, and the image side surface of the fifth single lens is convex; A sixth single lens with positive focal power, the object side surface of the sixth single lens is convex, and the image side surface of the sixth single lens is convex; A seventh single lens with negative focal power, the object side surface of the seventh single lens is concave, and the image side surface of the seventh single lens is concave; A second cemented doublet with positive focal power, which consists of a biconvex positive lens and a meniscus concave lens; the object side surface of the second cemented doublet is convex, and the image side surface of the second cemented doublet is convex; An eighth single lens with negative focal power, the object side surface of the eighth single lens is concave, and the image side surface of the eighth single lens is convex; An aperture stop, which is disposed between the fifth single lens and the sixth single lens.

2. The spherical ultra-wide-angle lens according to claim 1, characterized in that: The distance between the fifth single lens and the aperture stop is between 0.3 and 0.8 mm, and the distance between the aperture stop and the sixth single lens is between 0.1 and 0.3 mm; Or, the aperture stop is disposed on the surface of one of the optical elements within the first single lens, the second single lens, the third single lens, the fourth single lens, the first cemented doublet, the fifth single lens, the sixth single lens, the seventh single lens, the second cemented doublet, and the eighth single lens.

3. The spherical ultra-wide-angle lens according to claim 1, wherein: It further includes a filter, a sensor protection window, and an imaging surface disposed in sequence along the optical axis direction; The filter is disposed on one side of the image side surface of the eighth single lens for filtering light; the sensor protection window is used to protect the chip inside the optical system; the imaging surface is used for imaging.

4. The spherical ultra-wide-angle lens according to claim 3, wherein: The refractive index Nd of the materials of the filter and the sensor protection window satisfies 1.5 < Nd < 1.6, and the Abbe number 62 < Vd < 64; The distance between the filter and the eighth single lens is between 0.2 and 0.6 mm, the distance between the filter and the sensor protection window is between 0.5 and 2 mm, and the distance between the sensor protection window and the imaging surface is between 0.3 and 0.8 mm.

5. The spherical ultra-wide-angle lens according to claim 1, wherein: The object side surface of the meniscus negative lens is concave, and the image side surface of the meniscus negative lens is concave; the refractive index Nd of the material of the meniscus negative lens satisfies 1.7 < Nd < 1.8, and the Abbe number Vd satisfies 33 < Vd < 35; The object side of the meniscus positive lens is convex, and the image side of the meniscus positive lens is concave; the object side of the meniscus positive lens is bonded to the image side of the meniscus negative lens; the refractive index Nd of the material of the meniscus positive lens satisfies 1.4 < Nd < 1.5, and the Abbe number Vd satisfies 33 < Vd < 67.

6. The spherical ultra-wide-angle lens according to claim 1, wherein: The object side of the biconvex positive lens is convex, and the image side of the biconvex positive lens is convex; the refractive index Nd of the material of the biconvex positive lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 57 < Vd < 59; The object side of the meniscus negative lens is concave, and the image side of the meniscus negative lens is convex; the object side of the meniscus negative lens is concave and is bonded to the image side of the biconvex positive lens, and the refractive index Nd of the material of the meniscus negative lens satisfies 1.9 < Nd < 2.0, and the Abbe number Vd satisfies 30 < Vd < 32.

7. The spherical ultra-wide-angle lens according to claim 1, wherein: The focal length of the first single lens is between -0.02 and -0.06 mm. -1 between; And / or, the optical power of the second single lens is between -0.02 and -0.06 mm. -1 between; And / or, the optical power of the third single lens is 0.02~0.04mm -1 between; And / or, the optical power of the fourth single lens is 0.02~0.04mm -1 between; And / or, the optical power of the fifth single lens is 0.07~0.09mm -1 between; And / or, the optical power of the sixth single lens is 0.06~0.08mm -1 between; And / or, the optical power of the seventh single lens is between -0.04 and -0.06 mm. -1 between; And / or, the optical power of the eighth single lens is between -0.04 and 0.06 mm. -1 between.

8. The spherical ultra-wide-angle lens according to claim 1, wherein: The optical elements in the spherical ultra-wide-angle lens satisfy at least one or more of the following inequalities; The effective focal length f11 of the first singlet lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -4 < f11 / f < -2; The effective focal length f12 of the second singlet lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -4 < f12 / f < -1; The effective focal length f13 of the third singlet lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f13 / f < 4; The effective focal length f14 of the fourth singlet lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f14 / f < 4; The object-side lens effective focal length f151 of the first cemented doublet and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -0.2 < f151 / f < -2; The image-side lens effective focal length f152 of the first cemented doublet and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f152 / f < 4; The effective focal length f16 of the fifth singlet lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f16 / f < 4; The effective focal length f31 of the sixth singlet lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 1 < f31 / f < 4; The effective focal length f32 of the seventh singlet lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -4 < f32 / f < -1; The object-side lens effective focal length f331 of the second cemented doublet and the effective focal length f of the spherical ultra-wide-angle lens satisfy: 0.1 < f331 / f < 2; The image-side lens effective focal length f332 of the second cemented doublet and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -2 < f331 / f < -0.1; The effective focal length f34 of the eighth singlet lens and the effective focal length f of the spherical ultra-wide-angle lens satisfy: -4 < f34 / f < -1.

9. The spherical ultra-wide-angle lens according to claim 1, wherein: The spacing intervals between the various optical elements in the spherical ultra-wide-angle lens satisfy at least one or more of the following spacing intervals; The distance between the first single lens and the second single lens is between 6 and 8 mm, the distance between the second single lens and the third single lens is between 3 and 5 mm, the distance between the third single lens and the fourth single lens is between 0.1 and 0.2 mm, the distance between the fourth single lens and the first cemented group is between 1 and 3 mm, and the distance between the first cemented group and the fifth single lens is between 0.05 and 0.2 mm; The distance between the sixth single lens and the seventh single lens is between 0.1 and 0.2 mm, the distance between the seventh single lens and the second cemented group is between 0.7 and 0.9 mm, and the distance between the second cemented group and the eighth single lens is between 3 and 5 mm.

10. The spherical ultra-wide-angle lens according to claim 1, wherein: The refractive index and Abbe number of the materials used for each optical element in the spherical ultra-wide-angle lens satisfy at least one or more of the following inequalities; The refractive index Nd of the material of the first single lens satisfies 1.7 < Nd < 1.8, and the Abbe number Vd satisfies 49 < Vd < 51; The refractive index Nd of the material of the second single lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 55 < Vd < 57; The refractive index Nd of the material of the third single lens satisfies 1.8 < Nd < 1.9, and the Abbe number Vd satisfies 39 < Vd < 41; The refractive index Nd of the material of the fourth single lens satisfies 1.8 < Nd < 1.9, and the Abbe number Vd satisfies 38 < Vd < 40; The refractive index Nd of the material of the fifth single lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 54 < Vd < 56; The refractive index Nd of the material of the sixth single lens satisfies 1.7 < Nd < 1.8, and the Abbe number Vd satisfies 53 < Vd < 55; The refractive index Nd of the material of the seventh single lens satisfies 1.5 < Nd < 1.6, and the Abbe number Vd satisfies 63 < Vd < 65; The refractive index Nd of the material of the eighth single lens satisfies 1.6 < Nd < 1.7, and the Abbe number Vd satisfies 57 < Vd < 59.

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