A fixed focus lens

Abstract

The application provides a fixed focus lens, which 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 arranged in sequence along an optical axis from an object side to an image side; 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, 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. The number of lenses and the focal power combination in the fixed focus lens are reasonably set, so that the fixed focus lens with a short focal length and a high resolution is realized, and the imaging resolution can reach 5 million pixels.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and more particularly to a fixed-focus lens. Background Technology

[0002] Currently, most smart devices are equipped with glass-plastic lenses. These lenses require mass production to amortize manufacturing costs; if demand is low, manufacturing costs are high. Some customized smart devices, due to insufficient demand for mass production, cannot use glass-plastic solutions and also face resolution issues. Summary of the Invention

[0003] This invention provides a fixed-focus lens. By reasonably setting the number of lenses and the combination of optical power in the fixed-focus lens, a fixed-focus lens with short focal length and high resolution can be achieved, with an imaging resolution of up to 5 million pixels.

[0004] This 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 sequentially along the optical axis from the object side to the image side;

[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 together 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 together 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, it also includes an aperture stop disposed on the fifth lens.

[0028] Optionally, it may also include a flat protective glass, which is located on the side of the twelfth lens away from the first lens.

[0029] This invention provides a fixed-focus lens, which includes a first lens to a twelfth lens. By reasonably setting the number of lenses and the optical power combination in the fixed-focus lens, a fixed-focus lens with short focal length and high resolution can be achieved, with an imaging resolution of up to 5 million pixels. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a fixed-focus lens provided in 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 of a fixed-focus lens provided in an embodiment of the present invention;

[0033] Figure 4 A ray fan pattern for a fixed-focus lens provided in an embodiment of the present invention;

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

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

[0036] Figure 7 This is a dot diagram of a fixed-focus lens provided in an embodiment of the present invention. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0038] Figure 1 This is a schematic diagram of a fixed-focus lens provided in an embodiment of the present invention, with reference to... Figure 1The fixed-focus lens includes 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, arranged sequentially along the optical axis from the object side to the image side. 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] This invention provides a fixed-focus lens, which includes a first lens 1 to a twelfth lens 12. By reasonably setting the number of lenses and the optical power combination in the fixed-focus lens, a fixed-focus lens with short focal length and high resolution can be achieved, and its imaging resolution can reach 5 million pixels.

[0040] Optionally, refer to Figure 1 Lens 1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 10, 11, and 12 are all glass spherical lenses. The fixed-focus lens provided in this embodiment of the 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, satisfying at least one of the following conditions:

[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 together 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 together 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, which satisfies: 1.03<|f11_12 / f|<2.03.

[0059] Optionally, the fixed-focus lens also includes an aperture stop 13, which is disposed on the fifth lens 5. The aperture stop 13 is positioned between the fourth lens 4 and the fifth lens 5.

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

[0061] Table 1. One design value for a fixed-focus lens.

[0062]

[0063] Table 1 shows one design value for a fixed-focus lens. The specific values ​​can be adjusted according to product requirements and are not intended to limit the embodiments of the present invention. The fixed-focus lens shown in Table 1 can be... Figure 1 As shown in the table. A lens generally consists of two surfaces, each of which is a refractive surface. The surface numbers in Table 1 are assigned according to the surfaces of each lens. The surface numbers are represented as follows:

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

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

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

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

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

[0069] “STO” indicates aperture 13, which is located on the front surface of the fifth lens 5;

[0070] “S11” represents the front surface of the sixth lens 6, and “S12” represents the rear 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 rear surface of the eighth lens 8.

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

[0073] “S18” represents the front surface of the tenth lens 10, and “S19” represents the rear 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 rear surface of the twelfth lens 12.

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

[0076] In the "Surface Number" column, "IMA" indicates the image plane of the fixed-focus lens. "STO" indicates the aperture stop. The radius of curvature represents the degree of curvature of the lens surface. A positive value indicates the surface bends towards the image plane, and a negative value indicates it bends towards the object plane. A positive radius of curvature value means the center of curvature is closer to the image plane (IMA); a negative radius of curvature value means the center of curvature is farther from the image plane (object plane). The units for radius of curvature, thickness, and net aperture are all mm. The value in the "Thickness" column represents the central axial distance between the current surface and the next surface. The "Refractive Index" column represents the refractive index of the medium between the current and next surfaces, representing the material's ability to deflect light. A blank space in the "Refractive Index" column represents the refractive index of air, which is 1. The Abbe number represents the dispersion characteristics of the material between the current and next surfaces; a blank space indicates the current location is air. The value in the "Net Aperture" column indicates the maximum light height corresponding to the current surface.

[0077] In one implementation, 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 in this embodiment of the invention achieves the following technical specifications:

[0081] Focal length: f = 4.4mm; Aperture: F = 2.08; Field of view (FOV) = 98.5°; Total optical system length (TTL) = 30.2mm.

[0082] Figure 2The polychromatic light diffraction MTF diagram of a fixed-focus lens provided in this embodiment of the invention shows that, at a spatial frequency of 300 lp / mm, the MTF value of the fixed-focus lens within a half-field angle of 49.25 degrees is mostly above 0.25, indicating that the fixed-focus lens has high resolution.

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

[0084] Figure 4 A ray fan pattern for a fixed-focus lens provided in 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) under different field of view angles of this fixed-focus lens is within 10μm and the curves are relatively concentrated, which ensures that the aberrations in different field of view areas are small, which means that the fixed-focus lens has well corrected the aberrations of the optical system.

[0085] Figure 5 A field curvature diagram of a fixed-focus lens provided for an embodiment of the invention, such as... Figure 5 As shown, the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height, which has no unit; where T represents the meridion and S represents the arc loss; from Figure 5 It can be seen that the fixed-focus lens provided in this embodiment effectively controls the field curvature of light from wavelengths of 470nm to 650nm, meaning that during 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 for an embodiment of the invention, with reference to... Figure 6 The horizontal axis represents the magnitude of distortion, in percentage; the vertical axis represents the normalized image height, which has no unit; Figure 6 As can be seen, the distortion of the fixed-focus lens provided in this embodiment is well corrected, resulting in better image distortion. It has low chromatic aberration and aberrations, solves the imaging problems in various bands, and can achieve high-resolution imaging.

[0087] Figure 7This invention provides a dot plot of a fixed-focus lens. The dot plot is one of the most commonly used evaluation methods in modern optical design. A dot plot refers to the pattern formed by the dispersion of light rays emitted from a single light source across a certain area after passing through an optical system, due to aberrations, causing the intersection points with the image plane to no longer converge at a single point.

[0088] like Figure 7 As shown, the fixed-focus lens provided in this embodiment of the invention exhibits relatively concentrated and uniformly distributed diffusion patterns for light of different wavelengths (0.470μm, 0.510μm, 0.555μm, 0.610μm and 0.650μm) in various fields of view. There is no phenomenon where the diffusion pattern in a certain field of view is separated vertically with wavelength, indicating that there is no obvious purple fringing. Meanwhile, the root mean square radius (RMS radius) of light rays of different wavelengths (0.470μm, 0.510μm, 0.555μm, 0.610μm, and 0.650μm) at various fields of view of this 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. Simultaneously, the geometrical radius (GEO radius) of light rays of different wavelengths (0.470μm, 0.510μm, 0.555μm, 0.610μm, and 0.650μm) at various fields of view of this 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 demonstrates that the fixed-focus lens exhibits good chromatic aberration and aberration characteristics, enabling high-resolution imaging.

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

Claims

1. A fixed-focus lens, characterized in that, The fixed-focus 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 arranged sequentially along the optical axis from the object side to the image side; the fixed-focus lens has twelve lenses with diopter. 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. The first lens has a convex object-side surface and a concave image-side surface; the second lens has a convex object-side surface and a concave image-side surface; the third lens is a biconcave lens; the fourth lens is a biconvex lens; the fifth lens has a concave object-side surface and a convex image-side surface; the sixth lens has a concave object-side surface and a convex image-side surface; the seventh lens is a biconcave lens; the eighth lens is a biconvex lens; the ninth lens is a biconvex lens; the tenth lens is a biconvex lens; the eleventh lens is a biconcave lens; and the twelfth lens is a biconvex lens. 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 the following condition: 5.52 < |f1 / f| < 6.52; 0.59 < |f² / f| < 1.59; 1.96 < |f³ / f| < 2.96; 1.22 < |f4 / f| < 2.22; The fifth lens has a focal length of f5, the sixth lens has a focal length of f6, the seventh lens has a focal length of f7, the eighth lens has a focal length of f8, the ninth lens has a focal length of f9, the tenth lens has a focal length of f10, the eleventh lens has a focal length of f11, and the twelfth lens has a focal length of f12, satisfying the following condition: 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.

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 seventh lens and the eighth lens are cemented together to form a cemented lens.

4. The fixed-focus lens according to claim 3, characterized in that, The combined focal length of the seventh lens and the eighth lens is f78, satisfying the following: 1.42 < |f78 / f | < 2.

42.

5. The fixed-focus lens according to claim 1, characterized in that, The eleventh lens and the twelfth lens are cemented together to form a cemented lens.

6. The fixed-focus lens according to claim 5, characterized in that, The combined focal length of the eleventh lens and the twelfth lens is f11_12, satisfying: 1.03 < |f11_12 / f | < 2.

03.

7. The fixed-focus lens according to claim 1, characterized in that, It also includes an aperture stop, which is disposed on the fifth lens.

8. The fixed-focus lens according to claim 1, characterized in that, It also includes a flat protective glass, which is located on the side of the twelfth lens away from the first lens.

Images