Prime lens

Abstract

The invention provides a prime lens. The prime lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens which are sequentially arranged from an object space to an image space along an optical axis, the first lens is a positive focal power lens, the second lens is a negative focal power lens, the third lens is a negative focal power lens, the fourth lens is a positive focal power lens, the fifth lens is a positive focal power lens, the sixth lens is a positive focal power lens, the seventh lens is a negative focal power lens, the eighth lens is a positive focal power lens, and the ninth lens is a positive focal power lens. The tenth lens is a positive focal power lens, the eleventh lens is a negative focal power lens, and the twelfth lens is a positive focal power lens. By reasonably setting the number of the lenses in the prime lens and the focal power combination, the prime lens with short focal length and high resolution is realized, and the imaging resolution can reach 5 million pixels.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular to a fixed-focus lens. Background Art

[0002] At present, most smart devices are equipped with glass-plastic optical lenses, which require mass production to spread the manufacturing costs. If the demand is small, the manufacturing cost will be high. Some customized smart devices cannot use glass-plastic solutions because the demand has not reached the level of mass production, and they face resolution issues. Summary of the invention

[0003] An embodiment of the present invention provides a fixed-focus lens. By reasonably setting the number of lenses and the combination of optical powers in the fixed-focus lens, a fixed-focus lens with a short focal length and high resolution is realized, and the imaging resolution thereof can reach 5 million pixels.

[0004] An embodiment of the present invention provides a fixed-focus lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens arranged in sequence from the object side to the image side along an optical axis;

[0005] The first lens is a positive power lens, the second lens is a negative power lens, the third lens is a negative power lens, the fourth lens is a positive power lens, the fifth lens is a positive power lens, the sixth lens is a positive power lens, the seventh lens is a negative power lens, the eighth lens is a positive power lens, the ninth lens is a positive power lens, the tenth lens is a positive power lens, the eleventh lens is a negative power lens, and the twelfth lens is a positive power lens.

[0006] Optionally, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens and the twelfth lens are all glass spherical lenses.

[0007] Optionally, the total focal length of the fixed-focus lens is f, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, and the focal length of the fourth lens is f4, satisfying at least one of the following conditions:

[0008] 5.52<|f1 / f|<6.52;

[0009] 0.59<|f2 / f|<1.59;

[0010] 1.96<|f3 / f|<2.96;

[0011] 1.22<|f4 / f|<2.22.

[0012] Optionally, the total focal length of the fixed-focus lens is f, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is f7, the focal length of the eighth lens is f8, the focal length of the ninth lens is f9, the focal length of the tenth lens is f10, the focal length of the eleventh lens is f11, and the focal length of the twelfth lens is f12, satisfying at least one of the following conditions:

[0013] 4.01<|f5 / f|<5.01;

[0014] 2.19<|f6 / f|<3.19;

[0015] 0.15<|f7 / f|<1.15;

[0016] 0.74<|f8 / f|<1.74;

[0017] 1.42<|f9 / f|<2.42;

[0018] 1.21<|f10 / f|<2.21;

[0019] 0.31<|f11 / f|<1.31;

[0020] 1.34<|f12 / f|<2.34.

[0021] Optionally, the seventh lens and the eighth lens are cemented to form a cemented lens.

[0022] Optionally, the total focal length of the fixed-focus lens is f, and the combined focal length of the seventh lens and the eighth lens is f78, satisfying:

[0023] 1.42<|f78 / f|<2.42.

[0024] Optionally, the eleventh lens and the twelfth lens are cemented to form a cemented lens.

[0025] Optionally, the total focal length of the fixed-focus lens is f, and the combined focal length of the eleventh lens and the twelfth lens is f11-12, satisfying:

[0026] 1.03<|f11_12 / f|<2.03.

[0027] Optionally, a stop is also included, and the stop is arranged on the fifth lens.

[0028] Optionally, a plane protective glass is further included, and the plane protective glass is located on a side of the twelfth lens away from the first lens.

[0029] An embodiment of the present invention provides a fixed-focus lens, which includes a first lens to a twelfth lens. By reasonably setting the number of lenses in the fixed-focus lens and the combination of optical focal lengths, a fixed-focus lens with a short focal length and high resolution is realized, and its imaging resolution can reach 5 million pixels. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic structural diagram of a fixed-focus lens provided by an embodiment of the present invention;

[0031] Figure 2 A polychromatic light diffraction MTF diagram of a fixed-focus lens provided in an embodiment of the present invention;

[0032] Figure 3 A spherical aberration curve diagram of a fixed-focus lens provided by an embodiment of the present invention;

[0033] Figure 4 A light fan diagram of a fixed-focus lens provided by an embodiment of the present invention;

[0034] Figure 5 A field curvature diagram of a fixed-focus lens provided by an embodiment of the invention;

[0035] Figure 6 A distortion diagram of a fixed-focus lens provided by an embodiment of the invention;

[0036] Figure 7 A point diagram of a fixed-focus lens provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0038] Figure 1 A schematic diagram of the structure of a fixed-focus lens provided by an embodiment of the present invention, referring to Figure 1The fixed focus lens comprises a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11 and a twelfth lens 12 which are arranged in sequence from the object side to the image side along the optical axis. The first lens 1 is a positive power lens, the second lens 2 is a negative power lens, the third lens 3 is a negative power lens, the fourth lens 4 is a positive power lens, the fifth lens 5 is a positive power lens, the sixth lens 6 is a positive power lens, the seventh lens 7 is a negative power lens, the eighth lens 8 is a positive power lens, the ninth lens 9 is a positive power lens, the tenth lens 10 is a positive power lens, the eleventh lens 11 is a negative power lens, and the twelfth lens 12 is a positive power lens.

[0039] An embodiment of the present invention provides a fixed-focus lens, which includes a first lens 1 to a twelfth lens 12. By reasonably setting the number of lenses in the fixed-focus lens and the combination of optical focal lengths, a fixed-focus lens with a short focal length and high resolution is realized, and its imaging resolution can reach 5 million pixels.

[0040] Optionally, refer to Figure 1 , the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the eleventh lens 11 and the twelfth lens 12 are all glass spherical lenses. The fixed-focus lens provided in the embodiment of the present invention adopts an all-glass structure.

[0041] Optionally, refer to Figure 1 , the total focal length of the fixed-focus lens is f, the focal length of the first lens 1 is f1, the focal length of the second lens 2 is f2, the focal length of the third lens 3 is f3, and the focal length of the fourth lens 4 is f4, and at least one of the following conditions is satisfied:

[0042] 5.52<|f1 / f|<6.52;

[0043] 0.59<|f2 / f|<1.59;

[0044] 1.96<|f3 / f|<2.96;

[0045] 1.22<|f4 / f|<2.22.

[0046] Optionally, refer to Figure 1 , the total focal length of the fixed-focus lens is f, the focal length of the fifth lens 5 is f5, the focal length of the sixth lens 6 is f6, the focal length of the seventh lens 7 is f7, the focal length of the eighth lens 8 is f8, the focal length of the ninth lens 9 is f9, the focal length of the tenth lens 10 is f10, the focal length of the eleventh lens 11 is f11, and the focal length of the twelfth lens 12 is f12, satisfying at least one of the following conditions:

[0047] 4.01<|f5 / f|<5.01;

[0048] 2.19<|f6 / f|<3.19;

[0049] 0.15<|f7 / f|<1.15;

[0050] 0.74<|f8 / f|<1.74;

[0051] 1.42<|f9 / f|<2.42;

[0052] 1.21<|f10 / f|<2.21;

[0053] 0.31<|f11 / f|<1.31;

[0054] 1.34<|f12 / f|<2.34.

[0055] Optionally, refer to Figure 1 , the seventh lens 7 and the eighth lens 8 are cemented to form a cemented lens.

[0056] Optionally, refer to Figure 1 , the total focal length of the fixed-focus lens is f, and the combined focal length of the seventh lens 7 and the eighth lens 8 is f78, satisfying: 1.42<|f78 / f|<2.42.

[0057] Optionally, refer to Figure 1 The eleventh lens 11 and the twelfth lens 12 are cemented to form a cemented lens.

[0058] Optionally, refer to Figure 1 , the total focal length of the fixed-focus lens is f, and the combined focal length of the eleventh lens 11 and the twelfth lens 12 is f11_12, satisfying: 1.03<|f11_12 / f|<2.03.

[0059] Optionally, the fixed-focus lens further includes an aperture 13, and the aperture 13 is arranged on the fifth lens 5. The aperture 13 is arranged between the fourth lens 4 and the fifth lens 5.

[0060] Optionally, refer to Figure 1 The fixed-focus lens further includes a plane protective glass 14 , which is located behind the twelfth lens 12 , and the plane protective glass 14 is located on a side of the twelfth lens 12 away from the first lens 1 .

[0061] Table 1 A design value of fixed focus lens

[0062]

[0063] Table 1 shows a design value of a fixed-focus lens, and its specific value can be adjusted according to product requirements and is not a limitation of the embodiments of the present invention. The fixed-focus lens shown in Table 1 can be Figure 1 As shown in . A lens generally includes two surfaces, each of which is a refractive surface. The surface numbers in Table 1 are numbered according to the surfaces of each lens. Among them, the surface numbers are expressed as:

[0064] “S1” represents the front surface (i.e., the object side) of the first lens 1, and “S2” represents the back surface (i.e., the image side) of the first lens 1;

[0065] “S3” represents the front surface of the second lens 2, and “S4” represents the back surface of the second lens 2;

[0066] “S5” represents the front surface of the third lens 3 , and “S6” represents the back surface of the third lens 3 ;

[0067] “S7” represents the front surface of the fourth lens 4, and “S8” represents the back surface of the fourth lens 4;

[0068] “S9” represents the front surface of the fifth lens 5, and “S10” represents the back surface of the fifth lens 5;

[0069] “STO” denotes a stop 13 which is provided on the front surface of the fifth lens 5;

[0070] “S11” represents the front surface of the sixth lens 6, and “S12” represents the back surface of the sixth lens 6;

[0071] “S13” represents the front surface of the seventh lens 7, “S14” represents the front surface of the eighth lens 8; “S15” represents the back surface of the eighth lens 8;

[0072] “S16” represents the front surface of the ninth lens 9, and “S17” represents the back surface of the ninth lens 9;

[0073] “S18” represents the front surface of the tenth lens 10, and “S19” represents the back surface of the tenth lens 10;

[0074] “S20” represents the front surface of the eleventh lens 11, “S21” represents the front surface of the twelfth lens 12, and “S22” represents the back surface of the twelfth lens 12;

[0075] “ S23 ” represents the front surface of the planar protective glass 14 , and “ S24 ” represents the rear surface of the planar protective glass 14 .

[0076] "IMA" in the "Surface Number" column indicates the image surface of the fixed-focus lens. "STO" indicates the aperture. The radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface is bent toward the image side, and a negative value indicates that the surface is bent toward the object side. A positive radius of curvature value indicates that the center of curvature is on the side of the surface close to the image side, that is, a positive value indicates that the surface is bent toward the image side IMA; a negative radius of curvature value indicates that the center of curvature is on the side of the surface far from the image side, that is, a negative value indicates that the surface is bent toward the object side. The units of the radius of curvature, thickness, and clear aperture are all mm. The value in the "Thickness" column indicates the central axial distance from the current surface to the next surface. The "Refractive Index" column indicates the refractive index of the medium between the current surface and the next surface, representing the ability of the material between the current surface and the next surface to deflect light. The blank in the "Refractive Index" column is the refractive index of air, which is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to light, and a blank indicates that the current position is air. The value in the "Clear Aperture" column indicates the corresponding maximum light height on the current surface.

[0077] In one embodiment, f1=26.49; f2=-4.81; f3=-10.81; f4=7.59; f5=19.84; f6=11.85; f7=-2.87; f8=5.45; f9=8.43; f10=7.54; f11=-3.55; f12=8.11; f78=-8.44; f11_12=6.73; f=4.4;

[0078] ∣f1 / f∣=6.02;∣f2 / f∣=1.09;∣f3 / f∣=2.46;∣f4 / f∣=1.72;∣f5 / f∣=4.51;∣f6 / f∣=2.69;∣f7 / f∣=0.65;∣f8 / f∣=1.24;∣f9 / f∣=1.92;∣f10 / f∣=1.71;∣f11 / f∣=0.81;∣f12 / f∣=1.84;∣f78 / f∣=1.92;

[0079] |f11_12 / f|=1.53.

[0080] The fixed-focus lens provided by the embodiment of the present invention achieves the following technical indicators:

[0081] Focal length: f=4.4mm; aperture: F=2.08; field of view FOV=98.5°; total length of optical system TTL=30.2mm.

[0082] Figure 2A polychromatic light diffraction MTF diagram of a fixed-focus lens provided in an embodiment of the present invention shows that, at a spatial frequency of 300lp / mm, the MTF values ​​of the fixed-focus lens within a field of view of 49.25 degrees at a half-field angle of view are mostly above 0.25, indicating that the fixed-focus lens has a relatively high resolution.

[0083] Figure 3 The spherical aberration curve diagram of a fixed-focus lens provided by an embodiment of the present invention is specifically a schematic diagram of the spherical aberration curve when the pupil radius is 1.0575 mm. Figure 3 As shown, the spherical aberration under different wavelengths (0.470μm, 0.510μm, 0.555μm, 0.610μm and 0.650μm) is within 0.02mm, and the wavelength curve is relatively concentrated, indicating that the spherical aberration of this fixed-focus lens is small.

[0084] Figure 4 A light fan diagram of a fixed-focus lens provided by an embodiment of the present invention, such as Figure 4 As shown, the imaging range of different wavelengths of light (0.470μm, 0.510μm, 0.555μm, 0.610μm and 0.650μm) at different field angles of the fixed-focus lens is all within 10μm and the curves are relatively concentrated, ensuring that the aberrations in different field areas are small, which means that the fixed-focus lens can better correct the aberrations of the optical system.

[0085] Figure 5 A field curvature diagram of a fixed-focus lens provided in an embodiment of the invention, such as Figure 5 As shown, the horizontal coordinate represents the magnitude of field curvature, in mm; the vertical coordinate represents the normalized image height, without unit; T represents meridian, S represents arc loss; Figure 5 It can be seen that the fixed-focus lens provided in this embodiment is effectively controlled in field curvature from light with a wavelength of 470nm to light with a wavelength of 650nm, that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small.

[0086] Figure 6 A distortion diagram of a fixed-focus lens provided in an embodiment of the invention, referring to Figure 6 , the horizontal coordinate represents the size of the distortion, the unit is %; the vertical coordinate represents the normalized image height, no unit; Figure 6 It can be seen that the distortion of the fixed-focus lens provided in this embodiment is well corrected, the imaging distortion is good, there is lower chromatic aberration and aberration, the imaging problem of each band is solved, and high-resolution imaging can be achieved.

[0087] Figure 7A spot diagram of a fixed focus lens provided in an embodiment of the present invention. The spot diagram is one of the most commonly used evaluation methods in modern optical design. The spot diagram refers to a diffuse pattern formed by many light rays emitted by a point light source after passing through an optical system, where the intersection points of the light rays with the image plane are no longer concentrated at the same point due to aberration, but are spread over a certain range.

[0088] like Figure 7 As shown, for the fixed-focus lens provided by the embodiment of the present invention, the diffusion patterns of light of different wavelengths (0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm and 0.650 μm) in each field of view are relatively concentrated and evenly distributed, and there is no phenomenon in which the diffusion pattern in a certain field of view is widely separated up and down with the wavelength, indicating that there is no obvious purple fringing. At the same time, the root mean square radius values ​​(RMS radius) of light of different wavelengths (0.470μm, 0.510μm, 0.555μm, 0.610μm and 0.650μm) at each field of view of the fixed-focus lens are 0.677μm, 1.667μm and 2.760μm, respectively, indicating that the RMS radius of each field of view is less than 3.0μm; at the same time, the geometric radius values ​​(GEO radius) of light of different wavelengths (0.470μm, 0.510μm, 0.555μm, 0.610μm and 0.650μm) at each field of view of the fixed-focus lens are 2.705μm, 7.222μm and 10.814μm, respectively, indicating that the GEO radius of each field of view is less than 15μm. This also shows that the chromatic aberration and aberration of the fixed-focus lens are good, and high-resolution imaging can be achieved.

[0089] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A fixed-focus lens, characterized in that: It includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens which are arranged in sequence from the object side to the image side along the optical axis; The first lens is a positive power lens, the second lens is a negative power lens, the third lens is a negative power lens, the fourth lens is a positive power lens, the fifth lens is a positive power lens, the sixth lens is a positive power lens, the seventh lens is a negative power lens, the eighth lens is a positive power lens, the ninth lens is a positive power lens, the tenth lens is a positive power lens, the eleventh lens is a negative power lens, and the twelfth lens is a positive power lens.

2. The fixed-focus lens according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens and the twelfth lens are all glass spherical lenses.

3. The fixed-focus lens according to claim 1, characterized in that: The total focal length of the fixed-focus lens is f, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, and the focal length of the fourth lens is f4, satisfying at least one of the following conditions: 5.52<|f1 / f|<6.52; 0.59<|f2 / f|<1.59; 1.96<|f3 / f|<2.96; 1.22<|f4 / f|<2.

22.

4. The fixed-focus lens according to claim 1, wherein: The total focal length of the fixed-focus lens is f, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is f7, the focal length of the eighth lens is f8, the focal length of the ninth lens is f9, the focal length of the tenth lens is f10, the focal length of the eleventh lens is f11, and the focal length of the twelfth lens is f12, satisfying at least one of the following conditions: 4.01<|f5 / f|<5.01; 2.19<|f6 / f|<3.19; 0.15<|f7 / f|<1.15; 0.74<|f8 / f|<1.74; 1.42<|f9 / f|<2.42; 1.21<|f10 / f|<2.21; 0.31<|f11 / f|<1.31; 1.34<|f12 / f|<2.

34.

5. The fixed-focus lens according to claim 1, wherein: The seventh lens and the eighth lens are cemented to form a cemented lens.

6. The fixed-focus lens according to claim 5, characterized in that: The total focal length of the fixed-focus lens is f, and the combined focal length of the seventh lens and the eighth lens is f78, satisfying: 1.42<|f78 / f|<2.

42.

7. The fixed-focus lens according to claim 1, wherein: The eleventh lens and the twelfth lens are cemented to form a cemented lens.

8. The fixed-focus lens according to claim 7, characterized in that: The total focal length of the fixed-focus lens is f, and the combined focal length of the eleventh lens and the twelfth lens is f11-12, satisfying: 1.03<|f11_12 / f|<2.

03.

9. The fixed-focus lens according to claim 1, wherein: It also includes an aperture stop, which is arranged on the fifth lens.

10. The fixed-focus lens according to claim 1, wherein: A planar protective glass is also included, and the planar protective glass is located on a side of the twelfth lens away from the first lens.

Images