A lens and camera device

Abstract

This invention discloses a lens and imaging device, comprising, from the object side to the image side, a first positive power lens, a second positive power lens, a first negative power lens, a second negative power lens, a third positive power lens, a fourth positive power lens, a third negative power lens, a filter, and an image plane arranged sequentially. The lens satisfies the following conditions: where f1 is the focal length of the first positive power lens, f is the focal length of the lens, and FOV is the field of view of the lens. This invention achieves an optical lens that combines high resolution with a large target surface, low cost, and a large aperture.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and more particularly to a lens and a camera device. Background Technology

[0002] Thanks to the rapid development of autonomous driving in recent years, automotive optical lenses are increasingly being used in the field of autonomous driving, especially in automotive lenses and LiDAR. In addition to the requirements of high pixel count and small size, these lenses have more and more other requirements, such as a large field of view, long focal length, small FNO, high illumination, and low distortion, among other performance requirements that vary depending on the application. However, it is often difficult to achieve good results in all aspects at the same time.

[0003] With the rapid development of the LiDAR field, the following problems still exist in current optical imaging lenses: 1. Existing fixed-focus lenses have small imaging surfaces, mostly concentrated at 1 / 2.7 inches, which cannot meet current usage requirements. 2. Existing fixed-focus lenses on the market generally have small apertures, with F-numbers of F1.6 and above. 3. The lenses have a large number of optical elements, which increases the overall lens size while improving image quality, making it impossible to meet the miniaturization design requirements.

[0004] Therefore, there is an urgent need in the market for an optical lens that combines high resolution with features such as large sensor size, low cost, and large aperture. Summary of the Invention

[0005] This invention provides a lens and a camera device to provide an optical lens that combines high resolution with features such as large target area, low cost, and large aperture.

[0006] This invention provides a lens in which a first positive power lens, a second positive power lens, a first negative power lens, a second negative power lens, a third positive power lens, a fourth positive power lens, a third negative power lens, a filter, and an image plane are arranged sequentially from the object side to the image side.

[0007] The lens meets the following conditions:

[0008]

[0009] Where f1 is the focal length of the first positive power lens, f is the focal length of the lens, and FOV is the field of view of the lens.

[0010] Furthermore, the first positive power lens is a meniscus lens, and its object-facing side is convex.

[0011] The second positive power lens is a biconvex lens;

[0012] The first negative power lens is a biconcave lens;

[0013] The second negative power lens is a biconcave lens;

[0014] The third positive power lens is a biconvex lens;

[0015] The fourth positive power lens is a biconvex lens;

[0016] The third negative power lens is a meniscus lens, and its object-facing side is convex.

[0017] Furthermore, the first positive power lens, the second positive power lens, the first negative power lens, the second negative power lens, and the third negative power lens are glass spherical lenses;

[0018] The third and fourth positive power lenses are either glass spherical lenses or glass aspherical lenses.

[0019] Furthermore, the central radius of curvature R2 of the image-side surface of the first positive power lens and the central radius of curvature R3 of the object-side surface of the second positive power lens satisfy the following:

[0020] Furthermore, the focal length f3 of the first negative power lens and the focal length f5 of the third positive power lens satisfy the following relationship:

[0021] Furthermore, the focal length f2 of the second positive power lens and the focal length f5 of the third negative power lens satisfy: f2≤23; f5≤15.

[0022] Furthermore, the Abbe number Vd1 of the first positive power lens and the Abbe number Vd6 of the fourth positive power lens satisfy: Vd1≤30; Vd6≥37.

[0023] Furthermore, the refractive index Nd4 of the second negative power lens and the refractive index Nd7 of the third negative power lens satisfy the following conditions: Nd4≤1.85; Nd7≤1.95.

[0024] Furthermore, an aperture stop is provided between the first negative power lens and the second negative power lens.

[0025] On the other hand, this application provides a camera device, which includes: imaging using a lens as described in any of the above claims.

[0026] This invention provides a lens and a camera device. The lens, arranged sequentially from the object side to the image side, comprises a first positive power lens, a second positive power lens, a first negative power lens, a second negative power lens, a third positive power lens, a fourth positive power lens, a third negative power lens, a filter, and an image plane. The lens satisfies the following conditions: Where f1 is the focal length of the first positive power lens, f is the focal length of the lens, and FOV is the field of view of the lens. In this embodiment of the invention, seven lenses of specific optical powers are arranged sequentially from the object side to the image side in a specific order within the lens, and the lens satisfies: An optical lens with high resolution, large target surface, low cost, and large aperture has been developed. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0028] Figure 1 This is a schematic diagram of the lens structure provided in an embodiment of the present invention;

[0029] Figure 2 The optical transfer function (MTF) curve of the lens provided in Embodiment 1 of the present invention at room temperature in the visible light band;

[0030] Figure 3 The field curvature and distortion diagram of the lens in the visible light band provided in Embodiment 1 of the present invention;

[0031] Figure 4 This is the lateral fan pattern of the lens in the visible light band provided in Embodiment 1 of the present invention;

[0032] Figure 5 This is a dot plot of the lens in the visible light band provided in Embodiment 1 of the present invention;

[0033] Figure 6 The optical transfer function (MTF) curve of the lens in the visible light band at room temperature provided in Embodiment 2 of the present invention;

[0034] Figure 7 The field curvature and distortion diagram of the lens in the visible light band provided in Embodiment 2 of the present invention;

[0035] Figure 8 This is the lateral fan pattern of the lens in the visible light band provided in Embodiment 2 of the present invention;

[0036] Figure 9This is a dot plot of the lens in the visible light band provided in Embodiment 2 of the present invention. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0038] Figure 1 This is a schematic diagram of a lens provided in Embodiment 1 of the present invention. The lens consists of a first positive power lens L1, a second positive power lens L2, a first negative power lens L3, a second negative power lens L4, a third positive power lens L5, a fourth positive power lens L6, a third negative power lens L7, a filter M, and an image plane N arranged sequentially from the object side to the image side.

[0039] The lens meets the following conditions:

[0040]

[0041] Where f1 is the focal length of the first positive power lens, f is the focal length of the lens, and FOV is the field of view of the lens.

[0042] An aperture stop P is provided between the first negative optical power lens and the second negative optical power lens.

[0043] The size of the aperture stop determines the system's aperture value and the depth of field during shooting. Its aperture size can be fixed, or an adjustable aperture stop can be placed as needed to achieve adjustable light transmission aperture, that is, to have the purpose of changing the system's aperture value and changing the depth of field.

[0044] In this embodiment of the invention, seven lenses of a specific optical power are arranged in a specific order from the object side to the image side within the lens, and the lens satisfies the following: An optical lens with high resolution, large target surface, low cost, and large aperture has been developed.

[0045] In order to further improve the imaging quality of the lens, in this embodiment of the invention, the first positive power lens is a meniscus lens, and its object-facing side is a convex surface.

[0046] The second positive power lens is a biconvex lens;

[0047] The first negative power lens is a biconcave lens;

[0048] The second negative power lens is a biconcave lens;

[0049] The third positive power lens is a biconvex lens;

[0050] The fourth positive power lens is a biconvex lens;

[0051] The third negative power lens is a meniscus lens, and its object-facing side is convex.

[0052] To further improve the imaging quality of the lens, in this embodiment of the invention, the first positive power lens, the second positive power lens, the first negative power lens, the second negative power lens, and the third negative power lens are glass spherical lenses.

[0053] The third and fourth positive power lenses are either glass spherical lenses or glass aspherical lenses.

[0054] To further improve the image quality and processing performance of the lens, in this embodiment of the invention, the central radius of curvature R2 of the image side of the first positive power lens and the central radius of curvature R3 of the object side of the second positive power lens satisfy the following:

[0055] To further improve the image quality of the lens, in this embodiment of the invention, the focal length f3 of the first negative power lens and the focal length f5 of the third positive power lens satisfy the following:

[0056] To further improve the imaging quality of the lens, in this embodiment of the invention, the focal length f2 of the second positive power lens and the focal length f5 of the third negative power lens satisfy: f2≤23; f5≤15.

[0057] In this embodiment of the invention, in order to achieve clear imaging over a wide temperature range, the Abbe number Vd1 of the first positive power lens and the Abbe number Vd6 of the fourth positive power lens satisfy the following conditions: Vd1 ≤ 30; Vd6 ≥ 37. Furthermore, satisfying Vd1 ≤ 30 and Vd6 ≥ 37 can also reduce chromatic aberration in the image, thereby improving image quality.

[0058] To improve the image quality and reduce the overall length of the lens, in this embodiment of the invention, the refractive index Nd4 of the second negative power lens and the refractive index Nd7 of the third negative power lens satisfy: Nd4 ≤ 1.85; Nd7 ≤ 1.95. Furthermore, satisfying Nd4 ≤ 1.85; Nd7 ≤ 1.95 can also reduce spherical aberration and improve image quality.

[0059] On the other hand, embodiments of the present invention provide a camera device, which includes: imaging using the above-described lens.

[0060] The optical performance achieved by the lens provided in this embodiment of the invention is as follows:

[0061] The optical lens can support imaging surfaces up to 1 / 1.4 inches, effectively achieving high resolution while ensuring image quality, and is suitable for use in environments ranging from -40℃ to 120℃. It can support sensors with a maximum imaging surface size of 1 / 1.4 inches, with a total lens mechanical length not exceeding 34mm; the MTF value reaches above 0.5 at 100lp / mm across the entire field of view; it has a large aperture of F-number 1.4, making it particularly suitable for monitoring needs under low-light conditions; and it can meet the requirements of different temperatures.

[0062] The following provides examples of lens parameters provided in embodiments of the present invention.

[0063] Example 1:

[0064] In the specific implementation process, the radius of curvature R, center thickness Tc, refractive index Nd, Abbe constant Vd, and conic coefficient k of each lens of the lens satisfy the conditions listed in Table 1:

[0065]

[0066] Table 1

[0067] It should be noted that the mirror serial numbers in Table 1 are Figure 1 The lens surface numbers in the lens structure diagram shown are from left to right.

[0068] In this embodiment of the invention, lenses L5 and L6 are aspherical lenses.

[0069] The aspherical conic coefficients can be defined using the following aspherical formulas, but are not limited to the following representations:

[0070]

[0071] Where Z is the axial sagitta of the aspherical surface in the Z direction; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the coefficient of the fitted cone; and AF are the coefficients of the 4th, 6th, 8th, 10th, 12th, and 14th order terms of the aspherical polynomial.

[0072]

[0073] Table 2

[0074] The lens provided in this embodiment has the following optical technical specifications:

[0075] Total optical length TTL≤33mm;

[0076] Lens focal length f: 20.8mm;

[0077] Lens field of view: 28.7°;

[0078] Lens optical distortion: 5.9%;

[0079] Lens system aperture: FNO≤1.4;

[0080] Lens image size: φ5.6mm.

[0081] In this embodiment, the focal length of lens L1 is f1, the focal length of the lens system is f, and the field of view of the lens is FOV, which satisfies... The central radius of curvature R2 of the image side of lens L1 and the central radius of curvature R3 of the object side of lens L2 satisfy the following relationship: The focal length f3 of lens L3 and the focal length f5 of lens L5 of the optical lens satisfy the following relationship: The focal length of lens L2 is f2 = 18.28, and the focal length of lens L5 is f5 = 14.51; the Abbe number of lens L1 is Vd1 = 29.13, and the Abbe number of lens L6 is Vd6 = 37.20; the refractive index of lens L4 is Nd4 = 1.75, and the refractive index of lens L7 is Nd7 = 1.95.

[0082] Example 2:

[0083] In the specific implementation process, the radius of curvature R, center thickness Tc, refractive index Nd, Abbe constant Vd, and conic coefficient k of each lens of the lens satisfy the conditions listed in Table 3:

[0084]

[0085] Table 3

[0086] It should be noted that the mirror serial numbers in Table 3 are... Figure 1 The lens surface numbers in the lens structure diagram shown are from left to right.

[0087] In this embodiment of the invention, lenses L5 and L6 are aspherical lenses.

[0088] The aspherical conic coefficients can be defined using the following aspherical formulas, but are not limited to the following representations:

[0089]

[0090] Where Z is the axial sagitta of the aspherical surface in the Z direction; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the coefficient of the fitted cone; and AF are the coefficients of the 4th, 6th, 8th, 10th, 12th, and 14th order terms of the aspherical polynomial.

[0091]

[0092] Table 4

[0093] The lens provided in this embodiment has the following optical technical specifications:

[0094] Total optical length TTL≤34mm;

[0095] Lens focal length f: 24.7mm;

[0096] Lens field of view: 24.6°;

[0097] Lens optical distortion: 4.9%;

[0098] Lens system aperture: FNO≤1.4;

[0099] Lens image size: φ5.6mm.

[0100] In Embodiment 2 of the present invention, the focal length of lens L1 is f1, the focal length of the lens is f, and the field of view of the lens is FOV, satisfying the following conditions: The central radius of curvature R2 of the image side of lens L1 and the central radius of curvature R3 of the object side of lens L2 satisfy the following relationship: The focal length f3 of lens L3 and the focal length f5 of lens L5 of the optical lens satisfy the following relationship: The focal length of lens L2 is f2 = 22.68, and the focal length of lens L5 is f5 = 14.46; the Abbe number of lens L1 is Vd1 = 17.98, and the Abbe number of lens L6 is Vd6 = 46.77; the refractive index of lens L4 is Nd4 = 1.85, and the refractive index of lens L7 is Nd7 = 1.73.

[0101] In summary, Examples 1 to 2 satisfy the relationships shown in Table 5 below.

[0102]

[0103] Table 5

[0104] The lens provided in this embodiment will be further described below through a detailed optical system analysis of the embodiment.

[0105] The optical transfer function is a relatively accurate, intuitive, and common way to evaluate the imaging quality of an optical system. The higher and smoother the curve, the better the imaging quality of the system and the better the correction of aberrations.

[0106] like Figure 2 The figure shown is an optical transfer function (MTF) curve of the lens provided in Embodiment 1 of the present invention at room temperature in the visible light band.

[0107] like Figure 3 The image shown is a field curvature and distortion diagram of the lens provided in Embodiment 1 of the present invention in the visible light band.

[0108] like Figure 4 The image shown is a lateral fan pattern of the lens provided in Embodiment 1 of the present invention in the visible light band.

[0109] like Figure 5 The image shown is a dot plot of the lens provided in Embodiment 1 of the present invention in the visible light band.

[0110] like Figure 6 The figure shown is an optical transfer function (MTF) curve of the lens provided in Embodiment 2 of the present invention at room temperature in the visible light band.

[0111] like Figure 7 The image shown is a field curvature and distortion diagram of the lens provided in Embodiment 2 of the present invention in the visible light band.

[0112] like Figure 8 The image shown is a lateral fan pattern of the lens in the visible light band provided in Embodiment 2 of the present invention.

[0113] like Figure 9 The image shown is a dot plot of the lens in the visible light band provided in Embodiment 2 of the present invention.

[0114] from Figure 2 and Figure 6 As can be seen from the figure, the optical transfer function (MTF) curve of the imaging system in the visible light region at room temperature is relatively smooth and concentrated, and the average MTF value of the entire field of view (half-image height Y' = 2.8 mm) reaches more than 0.5; it can be seen that the imaging system provided in this embodiment can meet high imaging requirements.

[0115] from Figure 3 and Figure 7 As can be seen, the field curvature of this imaging system is controlled within ±0.1mm. Field curvature is also known as "image field curvature." When a lens has field curvature, the intersection of the entire beam does not coincide with the ideal image point. Although a sharp image point can be obtained at each specific point, the entire image plane is a curved surface. T represents meridional field curvature, and S represents sagittal field curvature. The field curvature curve shows the distance from the current focal plane or image plane to the paraxial focal plane as a function of the field of view coordinates. The meridional field curvature data is the distance from the currently determined focal plane to the paraxial focal plane measured along the Z-axis, and is measured on the meridional (YZ plane). The sagittal field curvature data measures the distance measured on a plane perpendicular to the meridional plane. The baseline in the schematic diagram is on the optical axis, and the top of the curve represents the maximum field of view (angle or height). No units are set on the vertical axis because the curve is always normalized using the maximum radial field of view.

[0116] from Figure 3 and Figure 7 As can be seen, the distortion control of this imaging system is relatively good, within 10%. Generally speaking, lens distortion is actually a general term for the inherent perspective distortion of optical lenses, that is, distortion caused by perspective. This distortion is very detrimental to the image quality of a photograph, since the purpose of photography is reproduction, not exaggeration. However, because this is an inherent characteristic of lenses (convex lenses converge light rays, concave lenses diverge light rays), it cannot be eliminated, only improved. Figure 2 As can be seen, the distortion of the fixed-focus lens provided in Embodiment 1 of the present invention is 5.9%, while the distortion of the fixed-focus lens provided in Embodiment 2 of the present invention is only 4.9%. This distortion setting is to balance the focal length, field of view, and the size of the corresponding camera target surface. The deformation caused by the distortion can be corrected by post-image processing.

[0117] from Figure 4 and Figure 8 As can be seen from the image, the curves in the optical sector diagram are relatively concentrated, indicating that the spherical aberration and dispersion of this imaging system are well controlled.

[0118] from Figure 5 and Figure 9 As can be seen from this, the imaging system has a small and concentrated spot radius, and the corresponding aberrations and coma are also very good.

[0119] Figure 4 and Figure 8 In this diagram, EX represents the aberration in the X direction, EY represents the aberration in the Y direction, PX represents the normalized pupil coordinates in the X direction, and PY represents the normalized pupil coordinates in the Y direction.

[0120] In summary, the embodiments of the present invention provide a low-cost, large-area, large-aperture, high-resolution optical lens. By employing seven optical lenses with specific structural shapes, arranged sequentially from the object side to the image side, and through the specific allocation and combination of the optical powers of each lens, the imaging system achieves good distortion control and excellent imaging characteristics.

[0121] This invention provides a lens and a camera device. The lens, arranged sequentially from the object side to the image side, comprises a first positive power lens, a second positive power lens, a first negative power lens, a second negative power lens, a third positive power lens, a fourth positive power lens, a third negative power lens, a filter, and an image plane. The lens satisfies the following conditions: Where f1 is the focal length of the first positive power lens, f is the focal length of the lens, and FOV is the field of view of the lens. In this embodiment of the invention, seven lenses of specific optical powers are arranged sequentially from the object side to the image side in a specific order within the lens, and the lens satisfies: An optical lens with high resolution, large target surface, low cost, and large aperture has been developed.

[0122] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0123] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A lens characterized by comprising: The lens is arranged in order from the object side to the image side as a first positive lens, a second positive lens, a first negative lens, a second negative lens, a third positive lens, a fourth positive lens, a third negative lens, a filter and an image surface; wherein the lens is composed of seven lenses. The lens satisfies the following conditions: Wherein, f1 is the focal length of the first positive lens, f is the focal length of the lens, and FOV is the field of view of the lens. a focal length f3 of the first negative power lens and a focal length f5 of the third positive power lens satisfy:

2. The lens of claim 1, wherein The first positive lens is a meniscus lens, and the side facing the object side is convex. The second positive lens is a double convex lens. The first negative lens is a double concave lens. The second negative lens is a double concave lens. The third positive lens is a double convex lens. The fourth positive lens is a double convex lens. The third negative lens is a meniscus lens, and the side facing the object side is convex.

3. The lens of claim 1, wherein The first positive lens, the second positive lens, the first negative lens, the second negative lens and the third negative lens are glass spherical lenses. The third positive lens and the fourth positive lens are glass spherical lenses or glass aspherical lenses.

4. The lens of claim 1, wherein The first positive power lens has a center curvature radius R2 of the image side surface and the second positive power lens has a center curvature radius R3 of the object side surface, and a relationship between R2 and R3 is:

5. The lens of claim 1, wherein The focal length f2 of the second positive lens and the focal length f5 of the third positive lens satisfy: f2≤23mm; f5≤15mm.

6. The lens of claim 1, wherein The Abbe number Vd1 of the first positive lens and the Abbe number Vd6 of the fourth positive lens satisfy: Vd1≤30; Vd6≥37.

7. The lens of claim 1, wherein The refractive index Nd4 of the second negative lens and the refractive index Nd7 of the third negative lens satisfy: Nd4≤1.85; Nd7≤1.

95.

8. The lens of claim 1, wherein An aperture stop is arranged between the first negative lens and the second negative lens.

9. An image pickup device, characterized by comprising: The camera device is provided with the lens according to any one of claims 1 to 8.

Images