A micro lens

Abstract

The present application relates to the technical field of micro imaging system, disclose a kind of micro lens, by from object side to image side book sequentially set first lens group, optical cable and second lens group, wherein first lens group includes by object side to image side sequentially set first lens and second lens, second lens group includes third lens and fourth lens, first lens, second lens, third lens and fourth lens are all aspherical surface structure, first lens has negative optical power;Second lens has positive optical power;Third lens has positive optical power;Fourth lens has negative optical power, effectively collocates optical power, and realizes high resolution, good imaging quality, low cost, miniaturization by reasonable parameter matching, the optical system design that can keep stable imaging performance.

Description

Technical Field

[0001] This invention relates to the field of micro-imaging system technology, specifically a micro-lens. Background Technology

[0002] In recent years, with the increasingly widespread application of miniature lenses, people's requirements for them have also increased. Miniature lenses offer ideal image quality and miniaturized size, thus creating market demand. Currently, miniature lenses are mainly used in the medical field. Medical endoscopes, as examination tools for the human body, generally have performance parameters such as image clarity, field of view, and size. Existing medical endoscopes often use multiple lenses to ensure image quality, resulting in excessively large sizes, making miniaturization difficult, and causing uneven illumination, affecting imaging effect and speed, and potentially causing discomfort to the user. Summary of the Invention

[0003] In order to overcome the defects of the prior art, the present invention aims to provide a miniature lens to solve the technical problems of the prior art, such as the endoscope being too large, difficult to miniaturize, and having uneven illumination, which affects the imaging effect and speed.

[0004] This invention is achieved through the following technical solution:

[0005] A miniature lens includes a first lens group, an optical cable, and a second lens group arranged sequentially from the object side to the image side. The first lens group includes a first lens and a second lens arranged sequentially from the object side to the image side, and the second lens group includes a third lens and a fourth lens. The object side of the first lens has a planar structure, and the image side has a plano-concave structure. The object side of the second lens has a plano-convex structure, and the image side has a planar structure. The object side of the third lens has a planar structure, and the image side has a plano-convex structure. The object side of the fourth lens has a plano-concave structure, and the image side has a planar structure.

[0006] Preferably, the first lens 4 has negative optical power; the second lens has positive optical power; the third lens has positive optical power; and the fourth lens has negative optical power.

[0007] Preferably, the maximum half-image height / focal length Imeg / f of the first lens, second lens, third lens, and fourth lens satisfies the following conditions:

[0008] 1 <Imeg / f<1.3

[0009] Where Imeg is the maximum half-image height; f is the system focal length.

[0010] Furthermore, the half-image height / total optical length Imeg / TTL of the first, second, third, and fourth lenses satisfy the following conditions:

[0011] 0.25 <Imeg / TTL<0.35

[0012] Where Imeg is the maximum half-image height and TTL is the total optical length.

[0013] Preferably, the paraxial operation of the first lens, second lens, third lens, and fourth lens satisfies the following conditions:

[0014] 4≤F#≤6

[0015] F# indicates paraxial operation.

[0016] Preferably, the system focal lengths of the first lens, second lens, third lens, and fourth lens satisfy the following conditions:

[0017] 0.6mm≤f≤1mm

[0018] Where f is the system focal length.

[0019] Preferably, the total optical length of the first lens, the second lens, the third lens, and the fourth lens satisfies the following conditions:

[0020] 2.5mm≤TTL≤3.5mm.

[0021] Preferably, the dispersion coefficients of the first lens, second lens, third lens, and fourth lens satisfy the following conditions:

[0022] Vd2, Vd4 < 40; Vd1, Vd3 > 40

[0023] Wherein, Vd1 is the dispersion coefficient of the first lens; Vd2 is the dispersion coefficient of the second lens; Vd3 is the dispersion coefficient of the third lens; and Vd4 is the dispersion coefficient of the fourth lens.

[0024] Preferably, the surface shapes of the first lens, the second lens, the third lens, and the fourth lens satisfy the following equation:

[0025]

[0026] Where y is the radial coordinate value of the lens perpendicular to the optical axis, Z is the distance sag of the aspherical lens from the vertex of the aspherical surface when it is at a height of y along the optical axis, c = 1 / R, R represents the radius of curvature of the center of the aspherical lens surface, k represents the conic coefficient, and parameters A, B, C, D, E, and F are higher-order aspherical coefficients.

[0027] Preferably, the fourth lens is also provided with chip protective glass near the image side.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] This invention provides a miniature lens, comprising a first lens group, an optical cable, and a second lens group arranged sequentially from the object side to the image side. The first lens group includes a first lens and a second lens arranged sequentially from the object side to the image side. The second lens group includes a third lens and a fourth lens. All four lenses are aspherical structures. The first lens has negative optical power; the second lens has positive optical power; the third lens has positive optical power; and the fourth lens has negative optical power. This effective combination of optical power and reasonable parameter matching achieves high resolution, good image quality, low cost, and miniaturization. The total optical length can be as low as 3.1mm, and the external dimensions are 1.75*1.75mm. This optical system design maintains stable imaging performance within the 3-100mm imaging range. Attached Figure Description

[0030] Figure 1 This is an optical structure diagram of the miniature lens of the present invention;

[0031] Figure 2 This is a distortion diagram from an embodiment of the present invention;

[0032] Figure 3 This is a relative illumination diagram according to an embodiment of the present invention;

[0033] Figure 4 This is a transfer function curve for an object distance of 10mm in an embodiment of the present invention;

[0034] Figure 5 This is a transfer function curve for an object distance of 50mm in an embodiment of the present invention;

[0035] Figure 6 This is a transfer function curve for an object distance of 100mm in an embodiment of the present invention;

[0036] In the diagram: 1-First lens group; 2-Second lens group; 3-Aperture; 4-First lens; 5-Second lens; 6-Third lens; 7-Fourth lens; 8-Chip protective glass. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0038] The present invention will now be described in further detail with reference to the accompanying drawings:

[0039] The purpose of this invention is to provide a miniature lens to solve the technical problems in the prior art where endoscopes are too large, making miniaturization difficult, and the illumination is uneven, affecting the imaging effect and speed.

[0040] See Figure 1 This invention provides a miniature lens, comprising a first lens group 1, an aperture 3, and a second lens group 2 arranged sequentially from the object side to the image side; the first lens group 1 includes a first lens 4 and a second lens 5 arranged sequentially from the object side to the image side, and the second lens group 2 includes a third lens 6 and a fourth lens 7; the object side of the first lens 4 has a planar structure, and the image side has a plano-concave structure; the object side of the second lens 5 has a plano-convex structure, and the image side has a planar structure; the object side of the third lens 6 has a planar structure, and the image side has a plano-convex structure; the object side of the fourth lens 7 has a plano-concave structure, and the image side has a planar structure.

[0041] Specifically, the first lens 4 has negative optical power; the second lens 5 has positive optical power; the third lens 6 has positive optical power; and the fourth lens 7 has negative optical power.

[0042] Specifically, the half-image height / focal length Imeg / f of the first lens 4, the second lens 5, the third lens 6, and the fourth lens 7 satisfy the following conditions:

[0043] 1 <Imeg / f<1.3

[0044] Where Imeg is the maximum half-image height; f is the system focal length.

[0045] Among them, the half-image height / total optical length Imeg / TTL of the first lens 4, the second lens 5, the third lens 6, and the fourth lens 7 satisfy the following conditions:

[0046] 0.25 <Imeg / TTL<0.35

[0047] Where Imeg is the maximum half-image height and TTL is the total optical length.

[0048] Specifically, the paraxial operation of the first lens 4, the second lens 5, the third lens 6, and the fourth lens 7 meets the following conditions:

[0049] 4≤F#≤6

[0050] F# indicates paraxial operation.

[0051] Specifically, the focal lengths of the system consisting of the first lens 4, the second lens 5, the third lens 6, and the fourth lens 7 meet the following conditions:

[0052] 0.6mm≤f≤1mm

[0053] Where f is the system focal length.

[0054] Specifically, the total optical length of the first lens 4, the second lens 5, the third lens 6, and the fourth lens 7 satisfies the following conditions:

[0055] 2.5mm≤TTL≤3.5mm.

[0056] Specifically, the dispersion coefficients of the first lens 4, the second lens 5, the third lens 6, and the fourth lens 7 satisfy the following conditions:

[0057] Vd2, Vd4 < 40; Vd1, Vd3 > 40

[0058] Wherein, Vd1 is the dispersion coefficient of the first lens; Vd2 is the dispersion coefficient of the second lens; Vd3 is the dispersion coefficient of the third lens; and Vd4 is the dispersion coefficient of the fourth lens.

[0059] Specifically, the surface shapes of the first lens 4, the second lens 5, the third lens 6, and the fourth lens 7 satisfy the following equation:

[0060]

[0061] Where y is the radial coordinate value of the lens perpendicular to the optical axis, Z is the distance sag of the aspherical lens from the vertex of the aspherical surface when it is at a height of y along the optical axis, c = 1 / R, R represents the radius of curvature of the center of the aspherical lens surface, k represents the conic coefficient, and parameters A, B, C, D, E, and F are higher-order aspherical coefficients.

[0062] The present invention provides that the first lens 4, the second lens 5, the third lens 6 and the fourth lens 7 can be pure glass lenses or glass with adhesive.

[0063] See Figures 2-6 This indicates the optical performance of the miniature lens, in which... Figure 2 This indicates that the distortion of this miniature lens is less than 35%. Figure 3 This indicates the relative illumination of this miniature lens. The relative illumination of this lens can reach over 50%, which is consistent with human visual perception. Figures 4-6 The curves show the changes in FFT and MTF of this lens at three different object distances, indicating that this lens has excellent imaging performance at different object distances.

[0064] This embodiment provides a miniature lens, comprising a first lens group 1, an aperture 2, and a second lens group 3, arranged sequentially from the object side to the image side. The first lens group 1 includes a first lens 4 with negative optical power, a second lens 5 with positive optical power, a third lens 6 with positive optical power, and a fourth lens 7 with negative optical power. The object side of the first lens 4 has a planar structure, and the image side has a plano-concave structure; the object side of the second lens 5 has a plano-convex structure, and the image side has a planar structure; the object side of the third lens 6 has a planar structure, and the image side has a plano-convex structure; the object side of the fourth lens 7 has a plano-concave structure, and the image side has a planar structure; and a chip protective glass 8 is also provided near the image side of the fourth lens 7.

[0065] The main design parameters of this embodiment are shown in Table 1:

[0066] Table 1 Design parameters of the miniature lens

[0067] 1 System focal length f 0.8 2 F# 5 3 TTL 3.1 4 Imeg / f 1.25 5 Imeg / TTL 0.32

[0068] In this embodiment, the physical and optical parameters of the entire lens are shown in Table 2:

[0069] Table 2 Physical and optical parameters of miniature lenses

[0070]

[0071]

[0072] The higher-order coefficients of the aspherical lens in this embodiment are shown in Table 3:

[0073] Table 3 Higher-order coefficients of aspherical lenses

[0074]

[0075] The embodiments of the present invention adopt a four-element structure to achieve a short focal length of about 0.8mm, a maximum field of view of 120 degrees, and a compact size. In this embodiment, the total length is 3.1mm and the full image height can reach 2mm, which is a high-definition imaging system.

[0076] In summary, this invention provides a miniature lens, which consists of a first lens group, an optical cable, and a second lens group arranged sequentially from the object side to the image side. The first lens group includes a first lens and a second lens arranged sequentially from the object side to the image side. The second lens group includes a third lens and a fourth lens. The first, second, third, and fourth lenses are all aspherical structures. The first lens has negative optical power; the second lens has positive optical power; the third lens has positive optical power; and the fourth lens has negative optical power. By effectively matching the optical power and through reasonable parameter matching, a high resolution, good imaging quality, low cost, and miniaturization are achieved, enabling the optical system design to maintain stable imaging performance in the 3-100mm range.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A miniature lens, characterized in that, The system includes a first lens group (1), an aperture (3), and a second lens group (2) arranged sequentially from the object side to the image side. The first lens group (1) includes a first lens (4) and a second lens (5) arranged sequentially from the object side to the image side. The second lens group (2) includes a third lens (6) and a fourth lens (7). The object side of the first lens (4) is planar, and the image side is plano-concave. The object side of the second lens (5) is plano-convex, and the image side is planar. The object side of the third lens (6) is planar, and the image side is plano-convex. The object side of the fourth lens (7) is plano-concave, and the image side is planar. The miniature lens has 4 lenses with optical power; The first lens 4 has negative optical power; the second lens (5) has positive optical power; the third lens (6) has positive optical power; and the fourth lens (7) has negative optical power. The maximum half-image height / focal length Imeg / f of the first lens (4), the second lens (5), the third lens (6), and the fourth lens (7) satisfy the following conditions: 1 <Imeg / f<1.3 Where Imeg is the maximum half-image height; f is the lens focal length; The system focal lengths of the first lens (4), the second lens (5), the third lens (6), and the fourth lens (7) satisfy the following conditions: 0.6mm≤f≤1mm Where f is the lens focal length.

2. A miniature lens according to claim 1, characterized in that, The half-image height / total optical length Imeg / TTL of the first lens (4), the second lens (5), the third lens (6), and the fourth lens (7) satisfy the following conditions: 0.25 <Imeg / TTL<0.35 Where Imeg is the maximum half-image height and TTL is the total optical length.

3. A miniature lens according to claim 1, characterized in that, The paraxial operation of the first lens (4), the second lens (5), the third lens (6), and the fourth lens (7) satisfies the following conditions: 4≤F#≤6 Where F# is the paraxial working F number.

4. A miniature lens according to claim 1, characterized in that, The total optical length of the first lens (4), the second lens (5), the third lens (6), and the fourth lens (7) satisfies the following conditions: 2.5mm≤TTL≤3.5mm.

5. A miniature lens according to claim 1, characterized in that, The dispersion coefficients of the first lens (4), the second lens (5), the third lens (6), and the fourth lens (7) satisfy the following conditions: Vd2, Vd4 < 40; Vd1, Vd3 > 40 Wherein, Vd1 is the dispersion coefficient of the first lens; Vd2 is the dispersion coefficient of the second lens; Vd3 is the dispersion coefficient of the third lens; and Vd4 is the dispersion coefficient of the fourth lens.

6. A miniature lens according to claim 1, characterized in that, The first lens (4), the second lens (5), the third lens (6), and the fourth lens (7) are all aspherical structures, and the surface shapes of the first lens (4), the second lens (5), the third lens (6), and the fourth lens (7) satisfy the following equation: Where y is the radial coordinate value of the lens perpendicular to the optical axis, Z is the distance sag of the aspherical lens from the vertex of the aspherical surface when it is at a height of y along the optical axis, c=1 / R, R represents the radius of curvature of the center of the aspherical lens surface, k represents the conic coefficient, and parameters A, B, C, D, E, and F are higher-order aspherical coefficients.

7. A miniature lens according to claim 1, characterized in that, The fourth lens (7) is also provided with chip protective glass (8) near the image side.

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