Folding and super mixed achromatic lens, camera module and terminal equipment

Abstract

The invention relates to a refraction and super hybrid achromatic lens, a camera module and a terminal device, and belongs to the field of optical lenses, the refraction and super hybrid achromatic lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged from an object plane to an image plane along an optical axis; the first lens is an aspheric lens, the second lens is a super lens, the third lens is an aspheric lens, the fourth lens is an aspheric lens, and the fifth lens is an aspheric lens. According to the invention, only the combination of one super lens and four plastic lenses is adopted, and the achromatic characteristic of the super lens is utilized, so that the effect of low chromatic aberration of the visible light wave band is achieved while high image quality presentation is maintained.

Description

Technical Field

[0001] This invention belongs to the field of optical lenses, and specifically relates to a hybrid achromatic lens, camera module, and terminal device. Background Technology

[0002] With the development of smartphones and their gradual expansion in market share, people's requirements for mobile phone lens pixels are constantly increasing. Since the 21st century, the demand for mobile phone pixels has evolved from megapixels to tens of millions of pixels. At the same time, with the development of the consumer market, consumers have increasingly higher requirements for the overall imaging performance of mobile phones, such as image quality, purple fringing, and stray light. Meanwhile, mobile phones are constantly developing towards thinner and lighter designs, which makes it necessary to research mobile phone lenses with simple structure, miniaturization, and ultra-thin high image quality.

[0003] Traditional mobile phone lens materials typically use an all-plastic structure. Plastic materials have a high coefficient of thermal expansion, resulting in poor reliability at both high and low temperatures. Furthermore, due to the limited selectivity of refractive index in plastic lens materials, achieving the chromatic aberration performance required for mobile phone lenses is often more challenging. Summary of the Invention

[0004] This application provides a hybrid achromatic lens, camera module, and terminal device to at least solve the above-mentioned technical problems existing in the prior art.

[0005] The first aspect of this application provides a hybrid achromatic lens, comprising a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the object plane to the image plane; the first lens is an aspherical lens, the second lens is a superlens, the third lens is an aspherical lens, the fourth lens is an aspherical lens, and the fifth lens is an aspherical lens.

[0006] The first lens is a lens with positive optical power, its object-side surface is convex, and its image-side surface is concave; both the object-side and image-side surfaces of the first lens are aspherical. The second lens is a superlens with positive optical power, its object-side surface is planar, and its image-side surface has microstructures arranged. The third lens is a lens with positive optical power, its object-side surface is concave, and its image-side surface is convex; both the object-side and image-side surfaces of the third lens are aspherical. The fourth lens is a lens with positive optical power, its object-side surface is concave, and its image-side surface is convex; both the object-side and image-side surfaces of the fourth lens are aspherical. The fifth lens is a lens with negative optical power, its object-side surface is concave, and its image-side surface is concave; both the object-side and image-side surfaces of the fifth lens are aspherical.

[0007] In one possible implementation, the lens satisfies:

[0008] TTL / MIC≤0.5;

[0009] Where MIC is the maximum image circle size, and TTL is the distance from the center of the optical axis on the side of the first lens to the image plane.

[0010] In one possible implementation, the lens satisfies:

[0011]

[0012] Where FOV is the diagonal field of view and EFL is the focal length.

[0013] In one embodiment, the focal length of the lens satisfies: f≥2mm.

[0014] In one embodiment, the field of view of the lens satisfies: Fov ≥ 95°.

[0015] In one embodiment, the aperture number of the lens satisfies: F# < 2.25.

[0016] In one possible implementation, an aperture stop is also included, which is located in front of the first lens, between any two lenses, or after the fifth lens.

[0017] Furthermore, the aperture stop is positioned between the first lens and the second lens.

[0018] A second aspect of this application provides a camera module that includes the achromatic lens described above.

[0019] A third aspect of this application provides a terminal device that includes the aforementioned camera module. This terminal device can be a mobile phone, computer, or other portable electronic device. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the achromatic lens in Embodiment 1 of this application;

[0021] Figure 2 This is a schematic diagram of the MTF of the achromatic lens in Embodiment 1 of this application;

[0022] Figure 3 This is a schematic diagram of the blur spot of the achromatic lens in Embodiment 1 of this application;

[0023] Figure 4 This is the transverse chromatic aberration diagram of the achromatic lens in Embodiment 1 of this application;

[0024] Figure 5 This is a schematic diagram of the achromatic lens in Embodiment 2 of this application;

[0025] Figure 6 This is a schematic diagram of the MTF of the achromatic lens in Embodiment 2 of this application;

[0026] Figure 7 This is a schematic diagram of the blur spot of the achromatic lens in Embodiment 2 of this application;

[0027] Figure 8 This is the transverse chromatic aberration diagram of the achromatic lens in Embodiment 2 of this application;

[0028] Explanation of reference numerals in the attached figures:

[0029] 110. First lens; 120. Aperture stop; 130. Second lens; 140. Third lens; 150. Fourth lens; 160. Fifth lens; 200. Imaging plane. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings.

[0031] In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0032] A metasurface is an artificial material with a thickness smaller than the wavelength, composed of a series of micrometer-scale two-dimensional structural units. The manufacturing process of metasurfaces is relatively simple, employing conventional methods such as photolithography, sputtering, and spraying, resulting in low cost. By rationally designing metasurfaces, light field information can be collected, thereby obtaining images of objects. Metasurfaces control the phase, amplitude, and propagation direction of light through control unit structures (usually nanoscale structural units), thus achieving the purpose of manipulating light waves. Furthermore, the dispersion of metasurfaces differs significantly from that of traditional optical materials. Traditional optical materials exhibit greater dispersion in the short-wavelength range and less dispersion in the long-wavelength range, while metasurfaces exhibit the opposite, thus being beneficial for second-order spectral correction. Additionally, the Abbe number of metasurfaces has the opposite sign to the dispersion value of traditional optical materials, which also facilitates chromatic aberration correction. Combining the optical properties of traditional optical materials and metasurfaces makes hybrid refractory-metasurface systems highly promising for applications in ultra-thin, miniaturized, and high-image-quality scenarios such as mobile phones.

[0033] This application provides a hybrid achromatic lens, including a first lens 110, a second lens 130, a third lens 140, a fourth lens 150, and a fifth lens 160 arranged sequentially along the optical axis from the object plane to the image plane; the first lens 110 is an aspherical lens, the second lens 130 is a superlens, the third lens 140 is an aspherical lens, the fourth lens 150 is an aspherical lens, and the fifth lens 160 is an aspherical lens.

[0034] The first lens 110 is a lens with positive optical power, its object-side surface is convex, and its image-side surface is concave; both the object-side and image-side surfaces of the first lens 110 are aspherical. The second lens 130 is a superlens with positive optical power, its object-side surface is planar, and its image-side surface has microstructures arranged. The third lens 140 is a lens with positive optical power, its object-side surface is concave, and its image-side surface is convex; both the object-side and image-side surfaces of the third lens 140 are aspherical. The fourth lens 150 is a lens with positive optical power, its object-side surface is concave, and its image-side surface is convex; both the object-side and image-side surfaces of the fourth lens 150 are aspherical. The fifth lens 160 is a lens with negative optical power, its object-side surface is concave, and its image-side surface is concave; both the object-side and image-side surfaces of the fifth lens 160 are aspherical.

[0035] The above achromatic lenses satisfy the following:

[0036] TTL / MIC≤0.5;

[0037] MIC is the maximum image circle size, and the distance from the center of the optical axis on the object side of the first lens to the image plane is TTL.

[0038]

[0039] Where FOV is the diagonal field of view and EFL is the focal length.

[0040] Optionally, the first lens 110, the third lens 140, the fourth lens 150, and the fifth lens 160 are made of plastic, and the second lens 130 is a superlens;

[0041] Optionally, the achromatic mobile phone lens also includes an aperture stop, which can be located before the first lens, between any two lenses, or after the fifth lens. Preferably, the aperture stop is located between the first lens and the second lens.

[0042] The above-mentioned achromatic mobile phone lens has the following requirements: focal length f≥2mm; field of view Fov≥95°; aperture number F#<2.25.

[0043] This invention provides a hybrid achromatic mobile phone lens using only four aspherical plastic lenses and one metasurface. Its simple structure, small size, and cost-effectiveness are achieved while ensuring performance stability in high and low temperature reliability tests. By rationally allocating the phase of the metasurface, this hybrid achromatic mobile phone lens achieves ultra-low chromatic aberration performance: ≤1.5µm transverse chromatic aberration across the entire field of view (435nm-650nm wavelength) and ≤1µm chromatic aberration within the 0.8 field of view. This invention overcomes the limitations of existing technologies, such as long overall length and poor chromatic aberration performance.

[0044] Example 1

[0045] Table 1 shows the parameters of a superchromatic hybrid achromatic mobile phone lens provided in Example 1.

[0046] Figure 1

[0047]

[0048]

[0049] Figure 1 This is a schematic diagram of the structure of a hybrid achromatic mobile phone lens with refractive and superchromatic properties provided in an embodiment of the present invention at room temperature, as shown below. Figure 1 As shown in the figure, an embodiment of the present invention provides a hybrid achromatic mobile phone lens comprising a first lens 110, an aperture 120, a second lens 130, a third lens 140, a fourth lens 150, and a fifth lens 160 arranged sequentially along the optical axis from the object plane to the image plane. The lens has an f / n ≤ 2.25 to ensure sufficient light intake and clear imaging even in low-light conditions; where f / n is the aperture number.

[0050] As a possible implementation, at least one of the first lens 110, the second lens 130, the third lens 140, the fourth lens 150, and the fifth lens 160 is a metasurface lens.

[0051] Among them, metasurface lenses have the function of achromatic correction. By setting at least one lens in a hybrid achromatic mobile phone lens system to be a metasurface lens, chromatic aberration can be effectively corrected. Especially in systems with strong requirements for chromatic aberration correction, such as day and night confocal lenses, clear imaging can be achieved day and night confocal lenses.

[0052] As a feasible implementation method, the second lens is configured as a superlens, with its object side being a plane and its image side having a microstructure arrangement.

[0053] As a feasible implementation, the first lens 110, the second lens 130, the third lens 140, and the fifth lens 160 are made of plastic material and are all aspherical.

[0054] refer to Figure 1 Optionally, the achromatic mobile phone lens with super-refractive and super-refractive hybrid technology provided in this embodiment of the invention further includes an aperture stop 120, which is located in front of the first lens 110, or in the optical path between the first lens 110 and the second lens 130, or in the optical path between the second lens 130 and the third lens 140, etc.

[0055] As one possible implementation, the aperture stop 110 is located in front of the first lens 120.

[0056] like Figure 1 As shown, after the incident light passes through the first lens 110, it passes through the aperture, then through the superlens 130, the third lens 140, and then through the fourth lens 150 and the fifth lens 160, before converging on the imaging surface 200.

[0057] For example, Table 1 details the specific optical data parameters of each lens in a hybrid achromatic mobile phone lens provided by an embodiment of the present invention, using a feasible implementation method. The optical data parameters in Table 1 correspond to... Figure 1 The image shows a superchromatic hybrid achromatic mobile phone lens.

[0058] The first lens is a lens with positive optical power, its object-side surface is convex, and its image-side surface is concave; both the object-side and image-side surfaces of the first lens are aspherical. The second lens is a superlens, its object-side surface is planar, and its image-side surface has microstructures arranged. The third lens is a lens with positive optical power, its object-side surface is concave, and its image-side surface is convex; both the object-side and image-side surfaces of the third lens are aspherical. The fourth lens is a lens with positive optical power, its object-side surface is concave, and its image-side surface is convex; both the object-side and image-side surfaces of the fourth lens are aspherical. The fifth lens is a lens with negative optical power, its object-side surface is concave, and its image-side surface is concave; both the object-side and image-side surfaces of the fifth lens are aspherical.

[0059] Table 2 shows the parameters of each surface in the optical system provided in Example 1.

[0060] Table 2

[0061]

[0062]

[0063] The surface numbers are assigned according to the order of the surfaces of each lens. For example, surface number 1 represents the object side of the first lens 110, surface number 2 represents the image side of the first lens 10, and so on. The radius of curvature represents the degree of curvature of the lens surface; a positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. The value is "Infinity".

[0064] This indicates that the surface is planar; the spacing represents the central axial distance from the current surface to the next surface, the radius of curvature, and the unit of the spacing.

[0065] All dimensions are in millimeters (mm).

[0066] Its even-order aspherical surface shape satisfies the following equation:

[0067]

[0068] Where z is the distance from the vertex of the even-order aspherical surface along the optical axis, r is the height from the optical axis, c is the curvature 1 / R, R is the radius of curvature at the vertex of the lens, k is the conic coefficient -e2, and a2, a3, a4, a5, a6, a7, and a8 are the higher-order coefficients of the aspherical surface.

[0069] For example, Table 3 details the conic coefficient k and higher-order coefficients a2, a3, a4, a5, a6, a7, a8 of the aspherical lens surface in this embodiment according to a feasible implementation.

[0070] Table 3

[0071]

[0072] Here, -1.47E-03 indicates that the coefficient a2 with surface number 1 is -1.47E-03, and so on.

[0073] For example, Table 4 details the phase of the metasurface in this embodiment with a feasible implementation.

[0074] Table 4

[0075] Face number R1 A1 A2 A3 A4 A5 9 1.00E+00 -9.24E+1 -1.92E+03 5.00E+4 -8.8E+5 8.1E+6 Face number A6 A7 A8 A9 A10 9 -3.8E+7 8.7E+7 -4.51E+8 7.73E+8 -1.29E+9

[0076] Where R1 is the normalized radius of the binary surface.

[0077] The mobile phone lens provided in this embodiment operates in the visible light band, has an F-number of 2.2, a focal length of 2.10mm, and a maximum field of view of 93.5°.

[0078] Figure 5 This is a schematic diagram of the blur pattern of a mobile phone lens provided in an embodiment of the present invention. The hybrid superconducting mobile phone lens provided in this embodiment of the present invention has a relatively concentrated and uniformly distributed blur pattern across the entire long-wavelength band, which can meet the requirements of high-resolution imaging.

[0079] Figure 6 This is a schematic diagram of the transverse chromatic aberration of a visible light projection lens provided in an embodiment of the present invention, which represents the transverse chromatic aberration values ​​corresponding to different fields of view, such as... Figure 6 As shown, the mobile phone lens provided in this embodiment of the invention has a transverse chromatic difference value of <1.5um within a 0.8 field of view in the working band.

[0080] Example 2

[0081] Table 5 shows the parameters of a superchromatic hybrid achromatic mobile phone lens provided in Example 2.

[0082] Table 5

[0083]

[0084] Table 6 shows the parameters of each surface in the optical system provided in Example 2.

[0085] Table 6

[0086]

[0087]

[0088] The surface number is assigned according to the order of the surfaces of each lens. For example, surface number 1 represents the object side of the first lens 110, surface number 2 represents the image side of the first lens 10, and so on. The radius of curvature represents the degree of curvature of the lens surface. A positive value means that the surface is curved toward the image surface, and a negative value means that the surface is curved toward the object surface. "Infinity" indicates that the surface is flat. The spacing represents the central axial distance from the current surface to the next surface. The units of the radius of curvature and the spacing are millimeters (mm).

[0089] Its even-order aspherical surface shape satisfies the following equation:

[0090]

[0091] Where z is the distance from the vertex of the even-order aspherical surface along the optical axis, r is the height from the optical axis, c is the curvature 1 / R, R is the radius of curvature at the vertex of the lens, k is the conic coefficient -e2, and a2, a3, a4, a5, a6, a7, and a8 are the higher-order coefficients of the aspherical surface.

[0092] For example, Table 7 details the conic coefficient k and higher-order coefficients a2, a3, a4, a5, a6, a7, a8 of the aspherical lens surface in this embodiment according to a feasible implementation.

[0093] Table 7

[0094]

[0095] Wherein, -7.51E-03 means that the coefficient a2 with surface number 1 is -7.51E-03, and so on.

[0096] For example, Table 7 details the phase of the metasurface in this embodiment with a feasible implementation.

[0097] Face number R1 A1 A2 A3 A4 A5 9 1.00E+00 -1.48E+2 -1.20E+3 4.90E+4 -9.01E+5 8.55E+6 Face number A6 A7 A8 A9 A10 9 -4.09E+7 7.58E+7 -1.50E+8 1.56E+9 -3.62E+9

[0098] Where R1 is the normalized radius of the binary surface.

[0099] For the analysis of each surface in Table 6, please refer to Example 1. This example will not analyze them further.

[0100] In summary, the super-hybrid achromatic mobile phone lens provided in this embodiment of the invention is small in size, short in total length, high in image quality, and low in chromatic aberration.

[0101] This application also provides a camera module, which includes the achromatic lens described above.

[0102] This application also provides a terminal device that includes the aforementioned camera module. This terminal device can be a mobile phone, computer, or other portable electronic device.

[0103] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A hybrid achromatic lens, characterized in that: It includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the object plane to the image plane; The first lens is an aspherical lens, the second lens is a superlens, the third lens is an aspherical lens, the fourth lens is an aspherical lens, and the fifth lens is an aspherical lens; The first lens is a lens with positive optical power, with its object side being convex and its image side being concave; both the object side and the image side of the first lens are aspherical. The second lens is a superlens with positive optical power, its object side is flat, and its image side has a microstructure arrangement; The third lens is a lens with positive optical power, with a concave object side and a convex image side. Both the object side and the image side of the third lens are aspherical. The fourth lens is a lens with positive optical power, with a concave object side and a convex image side. Both the object side and the image side of the fourth lens are aspherical. The fifth lens is a lens with negative optical power, with its object side and image side being concave. Both the object side and image side of the fifth lens are aspherical.

2. The achromatic lens according to claim 1, characterized in that, The lens satisfies: TTL / MIC≤0.5; Where MIC is the maximum image circle size, and TTL is the distance from the center of the optical axis on the side of the first lens to the image plane.

3. An achromatic lens according to claim 1, characterized in that, The lens satisfies: Where FOV is the diagonal field of view and EFL is the focal length.

4. An achromatic lens according to claim 1, characterized in that, The focal length of the lens satisfies: f≥2mm.

5. An achromatic lens according to claim 1, characterized in that, The field of view of the lens satisfies: Fov ≥ 95°.

6. An achromatic lens according to claim 1, characterized in that, The aperture number of the lens satisfies: F# < 2.

25.

7. An achromatic lens according to claim 1, characterized in that: It also includes an aperture stop, which is located in front of the first lens, between any two lenses, or after the fifth lens.

8. An achromatic lens according to claim 7, characterized in that: The aperture is positioned between the first lens and the second lens.

9. A camera module, characterized in that, Including the achromatic lens as described in any one of claims 1-8.

10. A terminal device, characterized in that, Includes the camera module as described in claim 9.

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