A high-pixel lens suitable for a wide band

Abstract

The present invention discloses a high-pixel lens suitable for a wide band, including: a first lens having positive focal power, a second lens spaced apart from the first lens, a third lens spaced apart from the second lens, a fourth lens having negative focal power and forming a double-cemented lens with the third lens, an aperture STO for limiting the beam aperture, a fifth lens having positive focal power and spaced apart from the aperture STO, a sixth lens having negative focal power, a seventh lens having positive focal power and forming a double-cemented lens with the sixth lens, an eighth lens having positive focal power, and a ninth lens having negative focal power and forming a double-cemented lens with the eighth lens. The technical solution achieves low distortion, low dispersion and high relative illumination while obtaining high-definition resolution by reasonably selecting the dispersion coefficient of the glass material and reasonably allocating the focal power of each lens, and obtains high imaging performance in the entire 436nm-1700nm band.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular to a high-pixel lens suitable for a wide band. Background Art

[0002] With the rapid development of artificial intelligence, the requirements for lenses in the fields of industrial automation, machine vision, and intelligent security are getting higher and higher, and lenses are usually required to capture as much target information as possible. However, the general lenses on the market only use the visible light band of 400-780nm, and cannot obtain clear target information at night or in other environments. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a high-pixel lens suitable for a wide band, which can be suitable for the requirements of a wide band, high pixels, high relative illumination, etc. in various environments.

[0004] According to an embodiment of the present invention, a high-pixel lens suitable for a wide band includes: a first lens having positive focal length, a dispersion coefficient Vd of the first lens, and a first lens having a positive focal length. 1 ≥30; a second lens having negative optical power and spaced apart from the first lens, the dispersion coefficient of the second lens being Vd 2 ≥60; a third lens having positive focal power and spaced apart from the second lens, the dispersion coefficient of the third lens being Vd 3 ≥60; the fourth lens has negative focal power and forms a doublet lens with the third lens, and the dispersion coefficient of the fourth lens is Vd 4 ≥20 and satisfy |Vd 3 -Vd 4 |≥40; a stop STO, which is spaced apart from the fourth lens and is used to limit the beam aperture; a fifth lens, which has a positive focal power and is spaced apart from the stop STO, and the dispersion coefficient of the fifth lens is Vd 5 ≥20; a sixth lens having negative optical power and spaced apart from the fifth lens, wherein the dispersion coefficient Vd of the sixth lens is 6 ≥60; the seventh lens has positive focal power and forms a doublet lens with the sixth lens, and the dispersion coefficient of the seventh lens is Vd 7 ≥70; an eighth lens having positive focal power and spaced apart from the seventh lens, the dispersion coefficient Vd of the eighth lens being 6 ≥90; the ninth lens has negative focal power and forms a doublet lens with the eighth lens, and the dispersion coefficient of the ninth lens is Vd 9 ≥50 and satisfy |Vd 8 -Vd 9 |≥40.

[0005] A high-pixel lens suitable for a wide band according to an embodiment of the present invention has at least the following beneficial effects:

[0006] This technical solution achieves high-definition resolution while achieving low distortion, low dispersion and high relative illumination by reasonably selecting the dispersion coefficient of glass materials and reasonably allocating the optical power of each lens, and obtains higher imaging performance in the entire band of 436nm-1700nm, with a small number of lenses, a simple structure and a compact optical system.

[0007] According to some embodiments of the present invention, the first lens has a convex surface facing the object side, and a concave surface facing the image side; the second lens has a convex surface facing the object side, and a concave surface facing the image side; the third lens has two convex surfaces; the fourth lens has a concave surface facing the object side, and a convex surface facing the image side; the fifth lens has a concave surface facing the object side, and a convex surface facing the image side; the sixth lens has a convex surface facing the object side, and a concave surface facing the image side; both surfaces of the seventh lens are convex; both surfaces of the eighth lens are convex; and both surfaces of the ninth lens are concave.

[0008] According to some embodiments of the present invention, the high-pixel lens satisfies the following relationship:

[0009] 2.5 <f 1 / f<3;

[0010] -2 <f 2 / f<-1;

[0011] 0.8 <f 3-4 / f<1.5;

[0012] 1.5 <f 5 / f<2.4;

[0013] -1.5 <f 6 / f<-0.5;

[0014] 0.3 <f 7 / f<1;

[0015] -2 <f 8-9 / f<-1;

[0016] 1.4 <TL / f<2.3;

[0017] Wherein, f is the focal length of the high-pixel lens, f 1 is the focal length of the first lens, f 2 is the focal length of the second lens, f 3-4 is the combined focal length of the third and fourth lenses, f 5is the focal length of the fifth lens, f 6 is the focal length of the sixth lens, f 7 is the focal length of the seventh lens, f 8-9 is the combined focal length of the eighth lens and the ninth lens, and TL is the overall length of the high-pixel lens.

[0018] According to some embodiments of the present invention, a photosensitive chip is further included, and the photosensitive chip is located on the image side and is spaced apart from the ninth lens.

[0019] According to some embodiments of the present invention, a protective glass is provided between the photosensitive chip and the ninth lens.

[0020] According to some embodiments of the present invention, the high-pixel lens satisfies the following relationship:

[0021] Nd 1 ≥1.6;

[0022] Nd 2 ≥1.5;

[0023] Nd 3 ≤1.6;

[0024] Nd 4 ≥1.7;

[0025] |Nd 3 -Nd 4 |≥0.15;

[0026] Nd 5 ≥1.9;

[0027] Nd 6 ≤1.6;

[0028] Nd 7 ≤1.6;

[0029] Nd 8 ≤1.5;

[0030] Nd 9 ≥1.6;

[0031] |Nd 8 -Nd 9 |≥0.1;

[0032] Among them, Nd 1 is the refractive index of the first lens, Nd 2 is the refractive index of the second lens, Nd 3 is the refractive index of the third lens, Nd 4 is the refractive index of the fourth lens, Nd 5 is the refractive index of the fifth lens, Nd 6is the refractive index of the sixth lens, Nd 7 is the refractive index of the seventh lens, Nd 8 is the refractive index of the eighth lens, Nd 9 is the refractive index of the ninth lens.

[0033] According to some embodiments of the present invention, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are all made of glass material lenses.

[0034] According to some embodiments of the present invention, the focal length of the high-pixel lens is f=35 mm, FNO=2.2, and the total length of the high-pixel lens is TL=65 mm.

[0035] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0037] Figure 1 A schematic diagram of a high-pixel lens structure according to an embodiment of the present invention;

[0038] Figure 2 This is an MTF curve diagram of an embodiment of the present invention when the object distance is 400mm;

[0039] Figure 3 This is a defocus MTF curve diagram of an embodiment of the present invention when the object distance is 400 mm;

[0040] Figure 4 This is a distortion curve diagram of an embodiment of the present invention when the object distance is 400 mm;

[0041] Figure 5 This is a relative illumination curve diagram of an embodiment of the present invention when the object distance is 400 mm;

[0042] Figure 6 This is a light aberration curve diagram of an embodiment of the present invention when the object distance is 400 mm;

[0043] Figure 7 This is an axial chromatic aberration curve diagram of an embodiment of the present invention when the object distance is 400 mm;

[0044] Figure 8 This is a vertical axis chromatic aberration curve diagram of an embodiment of the present invention when the object distance is 400 mm;

[0045] Fig. 9 This is an MTF curve diagram of an embodiment of the present invention when the object distance is 10000 mm.

[0046] Figure Number:

[0047] A first lens 1 , a second lens 2 , a third lens 3 , a fourth lens 4 , an aperture STO, a fifth lens 5 , a sixth lens 6 , a seventh lens 7 , an eighth lens 8 , a ninth lens 9 , a photosensitive chip 10 , and a protective glass 11 . DETAILED DESCRIPTION

[0048] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0049] In the description of the present invention, it should be understood that descriptions involving orientation, such as orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0050] In the description of the present invention, "a plurality" means more than two. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0051] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0052] Reference Figure 1 As shown in the figure, a high-pixel lens suitable for a wide band according to an embodiment of the present invention comprises: a first lens having a positive focal length, and a dispersion coefficient Vd of the first lens. 1 ≥30; a second lens having negative optical power and spaced apart from the first lens, the dispersion coefficient of the second lens being Vd 2 ≥60; a third lens having positive focal power and spaced apart from the second lens, the dispersion coefficient of the third lens being Vd 3 ≥60; the fourth lens has negative focal power and forms a doublet lens with the third lens, and the dispersion coefficient of the fourth lens is Vd 4 ≥20 and satisfy |Vd 3 -Vd 4|≥40; a stop STO, which is spaced apart from the fourth lens and is used to limit the beam aperture; a fifth lens, which has a positive focal power and is spaced apart from the stop STO, and the dispersion coefficient of the fifth lens is Vd 5 ≥20; a sixth lens having negative optical power and spaced apart from the fifth lens, wherein the dispersion coefficient Vd of the sixth lens is 6 ≥60; the seventh lens has positive focal power and forms a doublet lens with the sixth lens, and the dispersion coefficient of the seventh lens is Vd 7 ≥70; an eighth lens having positive focal power and spaced apart from the seventh lens, the dispersion coefficient Vd of the eighth lens being 6 ≥90; the ninth lens has negative focal power and forms a doublet lens with the eighth lens, and the dispersion coefficient of the ninth lens is Vd 9 ≥50 and satisfy |Vd 8 -Vd 9 |≥40.

[0053] Each lens in this lens has a reasonable distribution of optical power and material matching. Among them, the first lens has a positive optical power, which can converge a larger angle of off-axis light beam, thereby reducing the aperture of the rear optical path, which is beneficial to the correction of off-axis aberrations and the compactness of the optical path structure; the second lens has a higher Abbe number, which can directly reduce chromatic aberration; the third lens and the fourth lens have an Abbe number difference of more than 40 after being closely bonded, which can well correct chromatic aberration and secondary spectrum; after the light propagates for a long distance before and after the aperture, the accumulated chromatic aberration becomes larger, so the fifth lens uses an ultra-low dispersion material to reduce the difference between different wavelengths, thereby reducing chromatic aberration. The sixth lens has a high refractive index lens with negative optical power and the fifth lens to form a positive and negative lens combination, which effectively corrects spherical aberration, field curvature and dispersion; the seventh lens of the rear group has a positive optical power, which converges a large-diameter light beam and reduces high-order aberrations; the eighth lens and the ninth lens have an Abbe number difference of more than 40 after being closely bonded, which can also well correct chromatic aberration and secondary spectrum;

[0054] In some embodiments of the present invention, the first lens has a convex surface facing the object side, and a concave surface facing the image side; the second lens has a convex surface facing the object side, and a concave surface facing the image side; the third lens has two convex surfaces; the fourth lens has a concave surface facing the object side, and a convex surface facing the image side; the fifth lens has a concave surface facing the object side, and a convex surface facing the image side; the sixth lens has a convex surface facing the object side, and a concave surface facing the image side; the seventh lens has two convex surfaces; the eighth lens has two convex surfaces; the ninth lens has two concave surfaces. The above lens shape is only one embodiment of the present technical solution, and is not the only limitation. It can be replaced by lenses of other shapes that can achieve the same parameter performance.

[0055] In some embodiments of the present invention, the high-pixel lens satisfies the following relationship:

[0056] 2.5 <f 1 / f<3;

[0057] -2 <f 2 / f<-1;

[0058] 0.8 <f 3-4 / f<1.5;

[0059] 1.5 <f 5 / f<2.4;

[0060] -1.5 <f 6 / f<-0.5;

[0061] 0.3 <f 7 / f<1;

[0062] -2 <f 8-9 / f<-1;

[0063] 1.4 <TL / f<2.3;

[0064] Wherein, f is the focal length of the high-pixel lens, f 1 is the focal length of the first lens, f 2 is the focal length of the second lens, f 3-4 is the combined focal length of the third and fourth lenses, f 5 is the focal length of the fifth lens, f 6 is the focal length of the sixth lens, f 7 is the focal length of the seventh lens, f 8-9 is the combined focal length of the eighth lens and the ninth lens, and TL is the overall length of the high-pixel lens.

[0065] In this embodiment, the lens combination structure that satisfies the above relationship is conducive to achieving a reasonable distribution of optical power, and can better balance spherical aberration, coma, and field curvature. At the same time, the reasonable combination of materials is conducive to correcting chromatic aberration, thereby producing a high-resolution, high-quality imaging picture without color distortion.

[0066] like Figure 1 As shown, in some embodiments of the present invention, a photosensitive chip is also included. The photosensitive chip is located on the image side and is spaced apart from the ninth lens for capturing imaging signals and forming an image.

[0067] Furthermore, in some embodiments of the present invention, the protective glass between the photosensitive chip and the ninth lens can protect the chip from direct damage by external forces.

[0068] In some embodiments of the present invention, a high-pixel lens suitable for a wide band has a focal length of f=35 mm, FNO=2.2, and a total length TL=65 mm, and can be used with a 1 / 2” photosensitive chip.

[0069] In particular, in some embodiments of the present invention, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are all made of glass material lenses. Compared with plastic materials, they have higher transmittance, less final light energy loss, and better imaging transparency. At the same time, glass materials are not easy to age and deform, and have a longer service life; compared with glass aspherical lenses, they have lower costs.

[0070] In some embodiments of the present invention, by setting as little vignetting as possible or not setting vignetting, as much peripheral field light as possible can pass through the lens to reach the chip surface, so that the lens obtains a higher relative illumination and ensures the overall uniformity and transparency of the image plane brightness.

[0071] The specific parameters of the lens in this embodiment are shown in Table 1 below:

[0072] Face number Radius R thickness Refractive index Nd Abbe number Vd Physical surface Infinity Infinity - - S1 20.257 2.38 1.65 33.90 S2 29.022 2.94 - - S3 19.969 3.98 1.52 64.06 S4 11.03 9.63 - - S5 18.399 4.80 1.59 68.35 S6 -14.405 1.92 1.74 28.29 S7 -1194.013 2.07 - - STO(S8) Infinity 1.51 - - S9 -21.706 1.94 1.92 20.88 S10 -16.525 0.2 - - S11 59.471 1.84 1.52 64.21 S12 11.648 10.57 - - S13 19.922 2.97 1.57 71.30 S14 -31.142 0.11 - - S15 10.965 3.9 1.44 94.52 S16 -33.995 1.91 1.57 56.06 S17 8.488 12.13 - - S18 Infinity 1.2 1.52 64.21 S19 Infinity 1 - - S20 Image plane - - -

[0073] Table 1

[0074] In the above Table 1, the units of radius R and thickness are both millimeters.

[0075] For this fixed focal length lens, a floating focus adjustment method is used to meet the requirement of good imaging for different object distances. One embodiment of the present invention is to divide the system into two groups, front and rear, from the aperture, and achieve this purpose by adjusting the distance from the aperture STO to the rear group (i.e., the thickness of S8) and the back focus. The specific adjustment amount is shown in Table 2 below:

[0076] Object distance(mm) 200 500 2000 10000 S8 thickness (mm) 2.06 1.72 1.55 1.51 Back focus(mm) 18.22 14.50 12.71 12.24

[0077] Table 2

[0078] The present invention will be described in detail below in conjunction with the accompanying drawings, but the embodiments of the present invention are not limited to the following embodiments.

[0079] Figures 2 to 9 is an optical performance diagram of an embodiment of the present invention, wherein:

[0080] Figure 2 This is the MTF curve of a high-pixel lens at an object distance of 400mm, which is used to evaluate the resolution of a high-pixel lens. From the curve in the figure, it can be seen that the full-field MTF is greater than 0.5 at 100lp / mm, which has excellent resolution, and the trends of the on-axis and off-axis MTF curves are basically the same;

[0081] Figure 3This is the through-focus MTF curve of the high-pixel lens at an object distance of 400mm. It is used to analyze the overall uniformity and sharpness of the image after the light passes through the system. As can be seen from the figure, the best image plane coincidence of each field of view is very good, ensuring the imaging consistency of the peripheral field of view and the central field of view, and can be used for high-pixel chips;

[0082] Figure 4 This is the distortion curve of a high-pixel lens at an object distance of 400mm. The distortion is only -0.15% at full field of view, which is very small.

[0083] Figure 5 This is the relative illumination curve of a high-pixel lens at an object distance of 400mm. The relative illumination of the entire field of view is over 80%. A higher relative illumination can ensure uniformity of the overall picture brightness.

[0084] Figure 6 This is the light aberration curve of the high-pixel lens at an object distance of 400mm. The spherical aberration and chromatic aberration of the central field of view have been well corrected, and the performance of the off-axis field of view is basically the same;

[0085] Figure 7 This is the on-axis chromatic aberration curve of a high-pixel lens at an object distance of 400mm. The on-axis and off-axis aberrations are well corrected.

[0086] Figure 8 This is the vertical axis chromatic aberration of the high-pixel lens at an object distance of 400mm. The vertical axis chromatic aberration of the wavelength of 436-1700nm is all corrected within the diffraction limit range;

[0087] Fig. 9 This is the MTF curve of the high-pixel lens at an object distance of 10000mm. The MTF in the 0.7 field of view is greater than 0.8 at 100lp / mm, and the MTF in the 1 field of view is also greater than 0.4 at 100lp / mm, indicating that the lens has excellent imaging quality at long distances.

[0088] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A high-pixel lens suitable for a wide band, It is characterized in that The high-pixel lens has nine lenses, which are arranged in sequence from the object side to the image side: The first lens has positive power, and the dispersion coefficient of the first lens is Vd 1 ≥30; The second lens has a negative optical power and is spaced apart from the first lens. The dispersion coefficient Vd of the second lens is 2 ≥60; The third lens has positive power and is spaced apart from the second lens. The dispersion coefficient Vd of the third lens is 3 ≥60; The fourth lens has negative power and forms a doublet lens with the third lens. The dispersion coefficient of the fourth lens is Vd 4 ≥20 and satisfy |Vd 3 -Vd 4 |≥40; An aperture STO is spaced apart from the fourth lens and is used to limit a beam aperture; The fifth lens has positive power and is spaced apart from the stop STO. The dispersion coefficient of the fifth lens is Vd 5 ≥20; The sixth lens has negative power and is spaced apart from the fifth lens. The dispersion coefficient Vd of the sixth lens is 6 ≥60; The seventh lens has positive power and forms a doublet lens with the sixth lens. The dispersion coefficient of the seventh lens is Vd 7 ≥70; The eighth lens has positive power and is spaced apart from the seventh lens. The dispersion coefficient Vd of the eighth lens is 8 ≥90; The ninth lens has negative power and forms a doublet lens with the eighth lens. The dispersion coefficient of the ninth lens is Vd 9 ≥50 and satisfy |Vd 8 -Vd 9 |≥40; The first lens has a convex surface facing the object side, and a concave surface facing the image side; the second lens has a convex surface facing the object side, and a concave surface facing the image side; the third lens has two convex surfaces; the fourth lens has a concave surface facing the object side, and a convex surface facing the image side; the fifth lens has a concave surface facing the object side, and a convex surface facing the image side; the sixth lens has a convex surface facing the object side, and a concave surface facing the image side; both surfaces of the seventh lens are convex; both surfaces of the eighth lens are convex; and both surfaces of the ninth lens are concave.

2. A high-pixel lens suitable for a wide band according to claim 1, Features: The high-pixel lens satisfies the following relationship: 2.5<f 1 / f<3; -2<f 2 / f<-1; 0.8<f 3-4 / f<1.5; 1.5<f 5 / f<2.4; -1.5<f 6 / f<-0.5; 0.3<f 7 / f<1; -2<f 8-9 / f<-1; 1.4 <TL / f<2.3; Wherein, f is the focal length of the high-pixel lens, f 1 is the focal length of the first lens, f 2 is the focal length of the second lens, f 3-4 is the combined focal length of the third and fourth lenses, f 5 is the focal length of the fifth lens, f 6 is the focal length of the sixth lens, f 7 is the focal length of the seventh lens, f 8-9 is the combined focal length of the eighth lens and the ninth lens, and TL is the overall length of the high-pixel lens.

3. The high-pixel lens suitable for a wide band according to claim 1, Features: It also includes a photosensitive chip, which is located on the image side and spaced apart from the ninth lens.

4. A high-pixel lens suitable for a wide band according to claim 3, Features: A protective glass is provided between the photosensitive chip and the ninth lens.

5. The high-pixel lens suitable for a wide band according to claim 1, Features: The high-pixel lens satisfies the following relationship: Nd 1 ≥1.6; Nd 2 ≥1.5; Nd 3 ≤1.6; Nd 4 ≥1.7; |Nd 3 -Nd 4 |≥0.15; Nd 5 ≥1.9; Nd 6 ≤1.6; Nd 7 ≤1.6; Nd 8 ≤1.5; Nd 9 ≥1.6; |Nd 8 -Nd 9 |≥0.1; Among them, Nd 1 is the refractive index of the first lens, Nd 2 is the refractive index of the second lens, Nd 3 is the refractive index of the third lens, Nd 4 is the refractive index of the fourth lens, Nd 5 is the refractive index of the fifth lens, Nd 6 is the refractive index of the sixth lens, Nd 7 is the refractive index of the seventh lens, Nd 8 is the refractive index of the eighth lens, Nd 9 is the refractive index of the ninth lens.

6. The high-pixel lens suitable for a wide band according to claim 1, Features: The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens and the ninth lens are all made of glass material lenses.

7. The high-pixel lens suitable for a wide band according to claim 1, Features: The focal length of the high-pixel lens is f=35mm, FNO=2.2, and the total length of the high-pixel lens is TL=65mm.

Images