Five-piece imaging lens

Abstract

The invention discloses a five-piece imaging lens, and the lens sequentially comprises a first lens with negative refractive power, a second lens with negative refractive power, a third lens with negative refractive power, a fourth lens with negative refractive power, a fifth lens with negative refractive power and a sixth lens with negative refractive power from an object side to an image side along an optical axis, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a convex surface; the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a concave surface; the object side surface of the fifth lens is a plane, and the image side surface of the fifth lens is a plane; the object side surfaces and the image side surfaces of the first lens, the second lens, the third lens and the fourth lens are aspheric surfaces, the fifth lens is a super lens, and a diaphragm is arranged between the first lens and the second lens. The imaging lens integrates the advantages of high definition, miniaturization, small head and the like of imaging, meets the urgent requirements of the market for small-size and high-performance imaging lenses, and is suitable for equipment such as mobile phones, AR glasses, notebook computers and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical lens structure, and particularly relates to a five-piece imaging lens. BACKGROUND

[0002] In consumer electronics, optical lenses play a crucial role as the core vision component, responsible for accurately capturing environmental data and providing critical visual feedback to the system. They are widely used in consumer electronics such as mobile phones, AR glasses, and notebook computers. The performance of imaging lenses directly determines the efficiency level of the entire vision system, and their importance is self-evident. Due to the particularity and high requirements of consumer electronics applications, imaging lenses need to meet more stringent standards than ordinary lenses. Among them, the most critical is to achieve high definition and more compact size. Although there are optical lenses available on the market, there are still deficiencies in meeting the above high standards. Therefore, developing an imaging lens that can combine high definition, small size, and other characteristics is a problem that needs to be solved in the field. SUMMARY

[0003] The purpose of the present application is to provide a five-piece imaging lens to solve the problems of high cost and poor use effect of existing lenses.

[0004] To achieve the above purpose, the present application provides the following technical solution: a five-piece imaging lens, sequentially including from the object side to the image side along the optical axis: a first lens with negative refractive power, the object side surface is convex, and the image side surface is concave; a second lens with positive refractive power, the object side surface is convex, and the image side surface is convex; a third lens with positive refractive power, the object side surface is concave, and the image side surface is convex; a fourth lens with negative refractive power, the object side surface is convex, and the image side surface is concave; a fifth lens with negative refractive power, the object side surface is a plane, and the image side surface is a plane; The five lenses do not contact each other or only contact at the edge, and are not movable relative to each other. The object side surface and the image side surface of the first lens, the second lens, the third lens, and the fourth lens are aspherical surfaces. The fifth lens is a super lens, which can effectively reduce the thickness of the lens. The first lens and the second lens are provided with a diaphragm. The diaphragm is arranged at the image side surface of the first lens, which can realize high image quality and reduce the size of the head of the lens. The full field modulation transfer function MTF is greater than 62% at 110 lp / mm, the maximum field of view FOV is greater than 82.4°, the total optical length TTL is less than or equal to 2.53mm, and the working waveband is 400-700nm. max

[0005] ​Meanwhile, the imaging lens satisfies TTL / f < 1.64, where f is the focal length of the optical lens and TTL is the total optical length of the optical lens. By controlling its size, the overall length of the optical system can be effectively compressed, achieving miniaturization. The configuration of the first lens allows it to compress large-aperture light rays, increasing light transmission. The configuration of the second lens smoothly converges the large-aperture light rays transmitted from the front, which helps to eliminate aberrations generated by the first lens and reduce the system aperture. The configuration of the fourth and fifth lenses helps to move the principal point of the optical system away from the image side, thereby effectively shortening the overall length of the optical imaging system. The image sides of the third and fourth lenses both have a certain degree of curvature, which helps the optical system to increase the back focal length while matching the nonlinear CRA of the chip. The third and fourth lenses work together to receive the large-aperture light rays from the front and smoothly transition them to the rear, shortening the optical path difference between the center and the edge fields of view. This can effectively correct paraxial spherical aberration, reduce peripheral astigmatism curvature, and improve resolution.

[0006] Preferably, the imaging lens satisfies 0.69 < |f 123 / f|<0.98, where f 123 Let f be the combined focal length of the first, second, and third lenses, and let f be the effective focal length of the imaging lens. Controlling the above ratio can reduce the degree of refraction during light transmission, reduce the introduction of higher-order aberrations, and improve resolving power.

[0007] Preferably, the imaging lens satisfies 0.93 < |f 12 / f|<0.98, where f 12 Let f be the combined focal length of the first and second lenses, and f be the effective focal length of the imaging lens. Controlling their ratio helps to smoothly converge large-aperture light rays transmitted in front of the lens, reduce the introduction of higher-order aberrations, compress the system aperture, achieve smooth light transmission inside the optical lens, reduce the generation of higher-order aberrations, and improve the overall performance of the optical lens.

[0008] Preferably, the imaging lens satisfies 0.84 < |f 45 / f 12 |<1.12, where f 12 f is the combined focal length of the first and second lenses. 45 This refers to the combined focal length of the fourth and fifth lenses. Controlling their ratio allows for a reasonable allocation of optical power, reducing the deflection angle during light propagation, minimizing off-axis aberrations, and improving the overall performance of the lens.

[0009] Preferably, the imaging lens satisfies 0.81 < |f2 / f| < 0.85, 0.94 < |f3 / f| < 3.17, 0.96 < |f4 / f| < 3.06, where f is the effective focal length of the imaging lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, and f4 is the focal length of the fourth lens. Controlling the ratio can make the optical lens have low sensitivity and good imaging quality, and at the same time make the optical lens have a short optical length.

[0010] Preferably, the imaging lens satisfies 0.94 < (SAG5 / D5) / (SAG6 / D6) < 1.02, where SAG5 is the front surface sag of the third lens, D5 is the front surface diameter of the third lens, SAG6 is the rear surface sag of the third lens, and D6 is the rear surface diameter of the third lens. Controlling the ratio can make the shapes of the two surfaces of L3 similar, gently transition the peripheral light, and is beneficial to reducing the sensitivity of the lens.

[0011] Preferably, the imaging lens satisfies the following condition: 0.82 < (SAG7 / D7) / (SAG8 / D8) < 1.12, where SAG7 is the front surface sag of the fourth lens, D7 is the front surface diameter of the fourth lens, SAG8 is the rear surface sag of the fourth lens, and D8 is the rear surface diameter of the fourth lens. Controlling the ratio can make the shapes of the two surfaces of L4 similar, gently transition the peripheral light, and is beneficial to reducing the sensitivity of the lens.

[0012] Preferably, the imaging lens satisfies 0.34 < D1 / TTL < 0.39, where D1 is the effective diameter of the first lens and TTL is the total length of the imaging lens. Controlling its numerical value can effectively reduce the head size of the lens.

[0013] Preferably, the imaging lens satisfies 0.09 < (CT 12 +CT 23 +CT 34 +CT 45 ) / TTL < 0.12, where CT 12 is the air gap between the first lens and the second lens, CT 23 is the air gap between the second lens and the third lens, CT 34 is the air gap between the third lens and the fourth lens, CT 45 is the air gap between the fourth lens and the fifth lens, and TTL is the total optical length of the imaging lens. Controlling the above ratio can appropriately distribute the thickness of the lens, reduce the total length of the camera lens, and reduce the assembly difficulty of the camera lens, so that the assembly process can proceed smoothly and simply.

[0014] Preferably, the imaging lens satisfies the following conditions: 0.73 < CRA / FOV < 1.05, TTL < 2.53 mm, where FOV is the field angle of each field of view except the central field of view, CRA is the principal ray incident angle of each field of view except the central field of view, and TTL is the total optical length of the imaging lens. Controlling the above values can enable the optical lens to adapt to the non-linear CRA of current mainstream chips and meet the market demand of consumer electronics products.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: A five-piece imaging lens of the present invention has the advantages of miniaturization, small head, high resolution, etc. It is suitable for the cameras of portable devices such as AR glasses, mobile phones, tablets, computers, etc. And it has the following advantages: Extreme miniaturization and ultra-thinness: effectively compress the total length of the optical system and achieve a high degree of miniaturization.

[0016] Using a meta-lens as the fifth lens significantly reduces the overall thickness of the lens. Optimize the ratio of the total air gap between lenses to the total length, further compress the volume while ensuring performance, and simplify the assembly.

[0017] High image quality is achieved, and the modulation transfer function (MTF) of the full field of view is greater than 62% at 110 lp / mm, ensuring good resolution and clarity. It has a wide field angle and is suitable for wide-angle imaging requirements. Through the carefully designed lens combination and power distribution, spherical aberration, astigmatism, field curvature and other aberrations are effectively corrected, improving the overall resolution, especially in the edge field of view. Optimize the light transmission path and reduce the introduction of higher-order aberrations.

[0018] The negative refractive power configuration of the first lens and the convex surface design of the object surface help to compress large-aperture light, increase the light transmission amount, and improve the brightness of the lens. The positive refractive power and gentle convergence design of the second lens effectively eliminate the aberrations generated by the first lens and reduce the overall aperture of the system.

[0019] Setting the aperture stop on the image side of the first lens helps to achieve high image quality and reduces the head size of the lens. The configuration of the fourth and fifth lenses helps to move the principal point of the optical system away from the image side, further shortening the optical length. By controlling the ratio of CRA / FOV, the lens can be well adapted to the non-linear characteristics of current mainstream image sensor chips and meet the market demand of consumer electronics products.

[0020] The lenses do not touch each other or only touch at the edges and are immovable. The structure is relatively simple, which is beneficial to mass production and assembly. By controlling the similarity of the lens surface shapes, the sensitivity of the lens to tolerances is reduced, and the production yield and consistency are improved.

[0021] In summary, this five-element imaging lens, through ingenious optical design and structural optimization, achieves ultra-miniaturization and ultra-thinness while ensuring a wide field of view, high resolution, and good imaging quality. It is also highly compatible with mainstream chips, demonstrating significant technical advantages and application value. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the imaging lens in Embodiment 1 of the present invention.

[0024] Figure 2 This is a chromatic aberration curve of the imaging lens in Embodiment 1 of the present invention.

[0025] Figure 3 This is an MTF curve of the imaging lens in Embodiment 1 of the present invention.

[0026] Figure 4 This is a schematic diagram of the imaging lens in Embodiment 2 of the present invention.

[0027] Figure 5 This is a chromatic aberration curve of the imaging lens in Embodiment 2 of the present invention.

[0028] Figure 6 This is an MTF curve of the imaging lens in Embodiment 2 of the present invention.

[0029] Figure 7 This is a schematic diagram of the imaging lens in Embodiment 3 of the present invention.

[0030] Figure 8 This is a chromatic aberration curve of the imaging lens in Embodiment 3 of the present invention.

[0031] Figure 9 This is an MTF curve of the imaging lens in Embodiment 3 of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0033] The imaging lens of the present invention mainly includes lenses with optical power that are fixed sequentially along the optical axis from the object side to the image side, namely, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5.

[0034] The first lens L1 has negative refractive power. Its object-side surface S1 is convex to maximize the reception of large-aperture light rays transmitted from the front into the rear optical system, while its image-side surface S2 is concave to allow for rapid diffusion into the rear optical system. The configuration of the first lens L1 reduces light loss and improves illumination.

[0035] The second lens L2 has positive refractive power, and the object-side surface is S3, which is convex, while the image-side surface is S4, which is convex. It facilitates light convergence, expands the physical aperture of the aperture, achieves greater light transmission, increases the illumination of the image, and allows the light emitted from the first lens L1 to be smoothly incident on the rear.

[0036] The third lens L3 has positive refractive power, with a concave object-side surface S5 and a convex image-side surface S6. The fourth lens L4 has negative refractive power, with a convex object-side surface S7 and a concave image-side surface S8. The third and fourth lenses L3 and L4 work together to receive large-aperture light from the front and smoothly transition it to the rear, shortening the optical path difference between the center and edge fields of view, reducing distortion, and increasing illumination. Simultaneously, they effectively correct paraxial spherical aberration, reduce peripheral astigmatism curvature, and improve resolution. The front and rear surfaces of the third and fourth lenses L3 and L4 must have a certain degree of curvature to increase the back focal length and match the nonlinear CRA, which helps to converge light rays, correct aberrations, and improve the system's resolution. The object-side and image-side surfaces of each of the first to fourth lenses are aspherical.

[0037] The fifth lens, L5, is a superlens with negative refractive power. Its object-side surface S9 is flat, and its image-side surface S10 is also flat. This helps to move the principal point of the optical system away from the image-side end, thereby effectively shortening the overall length of the optical imaging system, effectively correcting paraxial spherical aberration, and reducing peripheral astigmatism curvature.

[0038] The imaging lens has a full-field modulation function (MTF) greater than 62% at 110 lp / mm, a field of view greater than 82°, a total optical length less than 2.53 mm, and an operating wavelength of 400-700 nm.

[0039] It should be noted that the object side of a lens refers to the side of the lens facing the subject, while the image side refers to the side of the lens facing the imaging plane. When a cross-section is made at any point on the object side surface of the lens, if the object side surface is always on the image side of the cross-section and its radius of curvature is positive, then the object side surface of the lens is convex; otherwise, it is concave. When a cross-section is made at any point on the image side surface of the lens, if the image side surface is always on the object side of the cross-section and its radius of curvature is negative, then the image side surface of the lens is convex; otherwise, it is concave. If a cross-section is made at any point on either the object side surface or the cross-section of the image side surface, and the object side surface or image side surface is partially on the image side and partially on the object side of the cross-section, then the surface has a point of inflection. The above method still applies to determining the convexity or concavity of the object side and image side surfaces near the optical axis.

[0040] Furthermore, the equation for the aspherical curve of an aspherical lens is expressed as follows: ; Where Z is the distance vector from the origin of the aspherical surface at a position of height r along the optical axis; c is the paraxial curvature of the aspherical surface (radius of curvature R = 1 / c, which is the reciprocal of the curvature); k is the conic coefficient; Ai is the i-th order coefficient of the aspherical surface, and the higher order coefficients used in this invention are A4, A6, A8, and A... 10 A 12 A 14 A 16 .

[0041] Furthermore, the phase plane equation of the superlens is expressed as follows: ; Where Φ is the cumulative phase difference of the light rays, N is the number of polynomial coefficients in the series, and A i It is the coefficient of ρ raised to the power of 2i, where ρ is the normalized radial aperture coordinate and M is the diffraction order.

[0042] In one embodiment, the five lenses do not contact each other or only contact at their edges, are immovable from each other, and both the object-side and image-side surfaces of each lens are aspherical, effectively reducing lens thickness. Simultaneously, the optical lens satisfies: TTL / f < 1.64, 0.69 < |f 123 / f|<0.98, 0.93<|f 12 / f|<0.98, 0.84<|f 45 / f 12 |<1.12, TTL is the total optical length of the imaging lens, f is the focal length of the imaging lens, f 12 f is the combined focal length of the first lens L1 and the second lens L2. 123 f is the combined focal length of the first lens L1, the second lens L2, and the third lens L3. 45The combined focal length of the fourth lens L4 and the fifth lens L5.

[0043] Below, an embodiment of a five-element imaging lens is described in detail with reference to the accompanying drawings.

[0044] Example 1 The structure of the imaging lens in this embodiment is as follows: Figure 1 As shown in the table below:

[0045] The remaining detailed parameters related to aspherical surfaces are shown in the table below:

[0046] The remaining detailed parameters of the superlens are shown in the table below:

[0047] Figure 2 The figure shows the vertical axis color difference curve of this embodiment. As shown in the figure, the color difference value between each wavelength is less than 1.4μm, which has a low color difference and a low risk of purple fringing. Figure 3 The figure shows the MTF curve of this embodiment. As shown, the MTF of the full field of view modulation function is greater than 62% at 110 lp / mm, indicating high clarity.

[0048] Example 2 The structure of the imaging lens in this embodiment is as follows: Figure 4 As shown in the table below:

[0049] The remaining detailed parameters related to aspherical surfaces are shown in the table below:

[0050] The remaining detailed parameters of the superlens are shown in the table below:

[0051] Figure 5 The figure shows the vertical axis color difference curve of this embodiment. As shown in the figure, the color difference value between each wavelength is less than 1.4μm, which has a low color difference and a low risk of purple fringing. Figure 6 The figure shows the MTF curve of this embodiment. As shown, the MTF of the full field of view modulation function is greater than 62% at 110 lp / mm, indicating high clarity.

[0052] Example 3 The structure of the imaging lens in this embodiment is as follows: Figure 7 As shown in the table below:

[0053] The remaining detailed parameters related to aspherical surfaces are shown in the table below:

[0054] The remaining detailed parameters of the superlens are shown in the table below:

[0055] Figure 8 The figure shows the vertical axis color difference curve of this embodiment. As shown in the figure, the color difference value between each wavelength is less than 1.4μm, which has a low color difference and a low risk of purple fringing. Figure 9 The figure shows the MTF curve of this embodiment. As shown, the MTF of the full field of view modulation function is greater than 62% at 110 lp / mm, indicating high clarity.

[0056] In summary, the aforementioned optical lens employs a structure of four plastic lenses plus one superlens, with a total optical length (TTL) ≤ 2.53mm and a maximum field of view (FOV). max With a focal length of f≥1.5mm and a full-field modulation function (MTF) greater than 62% at 110lp / mm, this optical lens operates in the 400-700nm wavelength range. It boasts advantages such as miniaturization, high resolution, small head size, and low chromatic aberration, while also exhibiting excellent optical imaging capabilities.

[0057] Within the technical scope disclosed in this invention, any variations or substitutions that can be easily conceived should be included within the protection scope of this invention. Therefore, the protection scope of this invention should be determined by the scope of the claims.

Claims

1. A five-element imaging lens, characterized in that, From the object side to the image side along the optical axis, it successively includes: A first lens with negative refractive power, the object side is convex and the image side is concave; A second lens with positive refractive power, the object side is convex and the image side is convex; A third lens with positive refractive power, the object side is concave and the image side is convex; A fourth lens with negative refractive power, the object side is convex and the image side is concave; A fifth lens with negative refractive power, the object side is flat and the image side is flat; The object side and the image side of the first lens, the second lens, the third lens and the fourth lens are both aspherical surfaces, the fifth lens is a super lens, and an aperture stop is arranged between the first lens and the second lens.

2. The five-element imaging lens according to claim 1, characterized in that: The imaging lens satisfies 0.69 < |f 123 / f|<0.98, where f 123 is the combined focal length of the first lens, the second lens, and the third lens, and f is the effective focal length of the imaging lens.

3. The five-element imaging lens according to claim 1, characterized in that: The imaging lens satisfies 0.93 < |f 12 / f|<0.98, where f 12 is the combined focal length of the first and second lenses, and f is the effective focal length of the imaging lens.

4. The five-element imaging lens according to claim 1, characterized in that: The imaging lens satisfies 0.84 < |f 45 / f 12 |<1.12, where f 12 f is the combined focal length of the first and second lenses. 45 This is the combined focal length of the fourth and fifth lenses.

5. The five-element imaging lens according to claim 1, characterized in that: The imaging lens satisfies 0.81 < |f2 / f| < 0.85, 0.94 < |f3 / f| < 3.17, 0.96 < |f4 / f| < 3.06, where f is the effective focal length of the imaging lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, and f4 is the focal length of the fourth lens.

6. The five-element imaging lens according to claim 1, characterized in that: The imaging lens satisfies 0.94 < (SAG5 / D5) / (SAG6 / D6) < 1.02, where SAG5 is the sag of the front surface of the third lens, D5 is the aperture of the front surface of the third lens, SAG6 is the sag of the rear surface of the third lens, and D6 is the aperture of the rear surface of the third lens.

7. The five-element imaging lens according to claim 1, characterized in that: The imaging lens satisfies the following condition: 0.82 < (SAG7 / D7) / (SAG8 / D8) < 1.12, where SAG7 is the sag of the front surface of the fourth lens, D7 is the aperture of the front surface of the fourth lens, SAG8 is the sag of the rear surface of the fourth lens, and D8 is the aperture of the rear surface of the fourth lens.

8. The five-element imaging lens according to claim 1, characterized in that: The imaging lens satisfies 0.34 < D1 / TTL < 0.39, where D1 is the effective aperture of the first lens and TTL is the total length of the imaging lens.

9. The five-element imaging lens according to claim 1, characterized in that: The imaging lens satisfies 0.09 < (CT) 12 +CT 23 +CT 34 +CT 45 ) / TTL < 0.12, where CT 12 The air gap between the first lens and the second lens, CT 23 The air gap between the second and third lenses, CT 34 The air gap between the third and fourth lenses, CT 45 The air gap between the fourth and fifth lenses is denoted by TTL, and the total optical length of the imaging lens is denoted by TTL.

10. The five-element imaging lens according to claim 1, characterized in that: The imaging lens satisfies the following conditions: 0.73 < CRA / FOV < 1.05, TTL < 2.53 mm, where FOV is the field angle of each field of view except the central field of view, CRA is the incident angle of the chief ray of each field of view except the central field of view, and TTL is the optical total length of the imaging lens.

Images