A large field of view, large aperture, fixed focus objective optical system

Abstract

The embodiment of the application discloses a large-field and large-aperture fixed focus objective optical system, a first lens group, the first lens group comprising a first lens, a second lens and a third lens; the first lens is a negative lens and the absolute value of the focal length is greater than 81mm, the sum of the focal lengths of the second lens and the third lens is 0; a second lens group, the second lens group is used for aberration complementation with the first lens group, the second lens group comprises a cemented lens, the cemented lens comprises a sixth lens and a seventh lens, wherein the cemented lens corrects spherical aberration and chromatic aberration by complementation; the second lens group is arranged on the image side of the first lens group; the second lens group further comprises a fifth lens; a diaphragm, the diaphragm is coplanar with the object side of the fifth lens; a third lens group, the third lens group is arranged on the image side of the second lens group; an image plane, the image plane is arranged on the image plane side of the third lens group.

Description

Technical Field

[0001] This application relates to the field of objective lens optical system technology, and in particular to a large field of view, large aperture fixed-focus objective lens optical system. Background Technology

[0002] Currently, optical instruments are increasingly used in both military and civilian fields. For scenarios with special requirements, such as geographic surveying, architectural photography, and others, night vision goggles on the market generally have a small field of view. Limited by the target size of the photoelectric conversion device and the weight requirements of the objective lens, the field of view of monocular night vision goggles is generally around 45 degrees, with a few reaching 50 degrees. However, in use, a 50-degree field of view provides the user with a field of vision that is roughly a square area between the shoulders and above the chest. To be able to see the situation on both sides, it is necessary to constantly move the head. At the same time, the sensitive field of view of the normal human eye is around 60 degrees. When using objective lenses with a field of view smaller than this, the human eye needs a certain amount of time to adapt. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] Therefore, a first aspect of the present invention provides an optical system for a large field of view and a large aperture fixed-focus objective lens, comprising: The first lens group includes a first lens, a second lens, and a third lens; The first lens is a negative lens and the absolute value of its focal length is greater than 81mm, while the sum of the focal lengths of the second and third lenses is 0.

[0005] The second lens group is used to complement the aberrations of the first lens group. The second lens group includes a cemented lens, which includes a sixth lens and a seventh lens. The cemented lens corrects spherical aberration and chromatic aberration through complementarity. The second lens group is disposed on the image-side side of the first lens group.

[0006] The second lens group also includes a fifth lens; An aperture stop, wherein the aperture stop is coplanar with the object-side surface of the fifth lens; A third lens group is disposed on the image-side surface of the second lens group; Image plane, which is disposed on the image plane side of the third lens group.

[0007] In one feasible implementation, the image plane size is a 1-inch micro-light CMOS or CCD.

[0008] In one feasible implementation, the first lens group further includes a fourth lens, and the first lens, the second lens, the third lens and the fourth lens are arranged sequentially from the object side to the image side along the optical axis; The second lens is a glass spherical lens with positive optical power, its object side is convex and its image side is concave; The third lens is a glass spherical lens with negative optical power, its object side is concave, and its image side is concave. The fourth lens is a glass spherical lens with negative optical power, its object side is concave and its image side is convex. The third lens group includes an eighth lens and a ninth lens, which are arranged sequentially from the object side to the image side along the optical axis. The eighth lens is a glass spherical lens with positive optical power, its object side is convex, and its image side is convex. The ninth lens is a glass spherical lens with positive optical power, its object side is concave and its image side is convex. The second lens group includes a fifth lens and a cemented lens, wherein the cemented lens includes a sixth lens and a seventh lens; The fifth lens is a glass spherical lens with positive optical power, its object side is convex, and its image side is convex. The sixth lens is a glass spherical lens with positive optical power, its object side is convex, and its image side is convex. The image side of the sixth lens and the object side of the seventh lens are bonded together with photosensitive adhesive. The seventh lens is a glass spherical lens with negative optical power, and its object side and image side are concave.

[0009] In one feasible implementation, the first lens satisfies -3.5 ≥ f A1 / Φ A1 ≥-4, where f A1 Φ represents the focal length of the first lens. A1 Indicates the effective aperture of the first lens; The second lens satisfies 2≥f A2 / Φ A2 ≥1.5, where f A2 Φ represents the focal length of the second lens. A2 Indicates the effective aperture of the second lens; The third lens satisfies -1.5 ≥ f A3 / Φ A3 ≥-2, where f A3 Indicates the focal length of the third lens; Φ A3 Indicates the effective aperture of the third lens; The fourth lens satisfies -30≥f A4 / Φ A4 ≥-35, where fA4 Φ represents the focal length of the fourth lens. A4 Indicates the effective aperture of the fourth lens; The fifth lens satisfies 1.5 ≥ f C1 / Φ C1 ≥1, where f C1 Φ represents the focal length of the fifth lens. C1 Indicates the effective aperture of the fifth lens; The sixth lens satisfies 2≥f C2 / Φ C2 ≥1, where f C2 Φ represents the focal length of the sixth lens. C2 Indicates the effective aperture of the sixth lens; The eighth lens satisfies 1.5 ≥ F. D1 / Φ D1 ≥1, where f D1 Φ represents the focal length of the eighth lens. D1 Indicates the effective aperture of the eighth lens; The ninth lens satisfies -2≥f D2 / Φ D2 ≥-2.5, where f D2 Φ represents the focal length of the ninth lens. D2 This indicates the effective aperture of the seventh lens.

[0010] In one feasible implementation, the optical system composed of the first lens group, the second lens group, the aperture stop, and the third lens group achieves optical parameters in the wavelength range of 450nm to 1000nm. The maximum distortion of the field of view is no greater than -5%; The pixel size is 800px × 600px; The field of view is 50° × 40°; The distorted diagonal field of view is 62°. f / L is greater than or equal to 0.3, where f represents the focal length of the objective lens and L represents the total optical length of the objective lens.

[0011] In one feasible implementation, the first lens satisfies the relationships Nd≥1.8, Vd≥40, and -82mm. <f A1 <-81mm, f A1 The focal length of the first lens; The second lens satisfies the relationships Nd≥1.7, Vd≥50, and 20mm. <f A2 <30mm, f A2 The focal length of the second lens; The third lens satisfies the relationships Nd≥1.65, Vd≥50, and -27mm. <f A3 <-25mm, fA3 The focal length of the third lens; The fourth lens satisfies the relationships Nd≥1.7, Vd≥50, and -480mm. <f A4 <-475mm, f A4 This is the focal length of the fourth lens; The fifth lens satisfies the relationships Nd≥1.7, Vd≥50, and 20mm. <f C1 <25mm, f C1 The focal length of the fifth lens; The sixth lens satisfies the relationships Nd≥1.7, Vd≥40, and 25mm. <f C2 <30mm, f C2 This is the focal length of the sixth lens; The seventh lens satisfies the relationships Nd≥1.8, Vd≥24, and -14mm. <f C3 <-13mm, f C3 This is the focal length of the seventh lens; The eighth lens satisfies the relationships Nd≥1.8, Vd≥40, and 16mm. <f D1 <18mm, f D1 This is the focal length of the eighth lens; The ninth lens satisfies the relationships Nd≥1.7, Vd≥45, and -36mm. <f D2 <-35mm, f D2 This is the focal length of the ninth lens; Where Nd is the glass refractive index of the lens, and Vd is the glass Abbe number of the lens.

[0012] In one feasible implementation, the first lens group, the second lens group, the aperture stop, and the third lens group are all made of white light glass. The first lens group, the second lens group, the aperture, and the third lens group are all coated to a wavelength range of 450nm to 1000nm.

[0013] In one feasible implementation, both the sixth and ninth lenses are made of flint glass.

[0014] In one feasible implementation, the second, third, and fourth lenses are made of crown glass material.

[0015] In one feasible implementation, the object-side radius of curvature of the first lens is 14.34 mm, the surface spacing is 1.33 mm, and the effective aperture is 23.1 mm; the image-side radius of curvature is 11.25 mm, the surface spacing is 6.38 mm, and the effective aperture is 20.2 mm. The second lens has an object-side radius of curvature of 20.02 mm, a surface spacing of 3.66 mm, and an effective aperture of 18.8 mm; and an image-side radius of curvature of 673.7 mm, a surface spacing of 3.95 mm, and an effective aperture of 17.6 mm. The third lens has an object-side radius of curvature of -455.8 mm, a surface spacing of 0.5 mm, and an effective aperture of 17.2 mm; and an image-side radius of curvature of 18.25 mm, a surface spacing of 3.97 mm, and an effective aperture of 13.9 mm. The fourth lens has an object-side radius of curvature of -10.93 mm, a surface spacing of 3.85 mm, and an effective aperture of 14.8 mm; and an image-side radius of curvature of -13.19 mm, a surface spacing of 4.3 mm, and an effective aperture of 15.5 mm. The fifth lens has an object-side radius of curvature of 21.01 mm, a surface spacing of 0.1 mm, and an effective aperture of 15.7 mm. The image-side radius of curvature is -68.13 mm, the surface spacing is 3.66 mm, and the effective aperture is 15.0 mm. The object-side radius of curvature of the sixth lens is 16.52 mm, the surface spacing is 0.5 mm, and the effective aperture is 15.7 mm. The image-side radius of curvature is -17.42 mm, the surface spacing is 4.3 mm, and the effective aperture is 15.4 mm. The seventh lens has an object-side radius of curvature of -17.42 mm, a surface spacing of 4.3 mm, and an effective aperture of 15.4 mm; and an image-side radius of curvature of 12.89 mm, a surface spacing of 1.82 mm, and an effective aperture of 13.9 mm. The eighth lens has an object-side radius of curvature of 19.1 mm, a surface spacing of 1.2 mm, and an effective aperture of 14.3 mm; and an image-side radius of curvature of -54.02 mm, a surface spacing of 8.04 mm, and an effective aperture of 14.5 mm. The ninth lens has an object-side radius of curvature of -12.72 mm, a surface spacing of 2.8 mm, and an effective aperture of 14.2 mm. The image-side radius of curvature of the ninth lens is -25.6 mm, the surface spacing is 1.14 mm, and the effective aperture is 15.2 mm.

[0016] Compared to existing technologies, the present invention offers at least the following advantages: In the optical system provided by the embodiments of this application, to address the problem of excessively large light angles caused by a 60-degree wide field of view and a large relative aperture, the present invention uses a first lens group where the first lens is a negative lens, the second lens is a positive lens, and the third lens is a negative lens. Its main characteristic is that the absolute value of the focal length of the first lens is particularly large and it is a negative lens. Furthermore, the sum of the focal lengths of the second and third lenses is approximately zero. Firstly, this design of the first lens's focal length effectively solves the problem of excessively large light angles caused by a 60-degree wide field of view and a large relative aperture. It also effectively improves the situation where the aperture of the first lens group in most wide field-of-view lenses on the market is much larger than that of the subsequent lens groups. In addition, the design that the sum of the focal lengths of the second and third lenses is approximately zero effectively solves the problem of large size caused by excessively long axial length and excessively long air layers in wide field-of-view objectives. It also solves the problem that the first lens group generally uses materials with high refractive index, high density, and high price.

[0017] The design of the first lens group in this invention achieves the following breakthroughs by rationally allocating the optical power of each lens within the first lens group: First, the first lens group effectively smooths out the large-angle incident light from large-field-of-view, large-relative-aperture objectives through rational optical power allocation, effectively shortening the objective focal length, making the objective suitable for 1-inch large-scale target detectors, greatly reducing the #F number, and effectively increasing the light transmission of low-light objectives; Second, it effectively balances the problem of excessively large mechanical aperture of the first lens group in large-field-of-view, large-relative-aperture objectives, enabling the entire objective barrel to have a consistent aperture, effectively reducing the objective volume, and making it very suitable for miniaturized applications; Third, it effectively shortens the axial length of the objective; Fourth, it significantly reduces the overall mass of the objective; Fifth, it effectively reduces costs.

[0018] It is evident that the present invention significantly improves the objective lens performance through the design of the first lens group.

[0019] Furthermore, through aberration complementarity between the first and second lens groups, the cemented lenses in the second lens group compensate for spherical and chromatic aberrations. The optical power of each lens is also rationally calculated to ensure no focal plane shift under both high and low temperatures, achieving a near-focal-state effect day and night. This results in high-quality pixels during the day while maintaining high-definition image quality at night or in low-light conditions. It also remains usable in environments with varying temperatures. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1A structural block diagram of a large field-of-view, large-aperture fixed-focus objective lens optical system according to an embodiment of this application; Figure 2 A light propagation path diagram of a large field-of-view, large-aperture fixed-focus objective lens optical system provided in this application; Figure 3 An optical transfer function diagram of a large field-of-view, large-aperture fixed-focus objective lens optical system provided in this application; Figure 4 An optical dot diagram of a large field-of-view, large-aperture fixed-focus objective lens optical system provided in this application; Figure 5 This is a schematic diagram of the optical field curvature and distortion of a large field-of-view, large-aperture fixed-focus objective lens optical system according to an embodiment of this application.

[0021] in, Figure 1-2 The correspondence between the reference numerals and component names in the attached drawings is as follows: 100, First lens group; 200, Second lens group; 300, Third lens group; 400, Image plane; 110. First lens; 120. Second lens; 130. Third lens; 140. Fourth lens; 210. Fifth lens; 220. Cemented lens; 310. Eighth lens; 320. Ninth lens; 211. The sixth lens; 212. The seventh lens. Detailed Implementation

[0022] To better understand the above technical solutions, the technical solutions of the embodiments of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0023] like Figure 1-5 As shown, according to an embodiment of this application, a large field of view and large aperture fixed-focus objective lens optical system is proposed, including: a first lens group 100, wherein the first lens group 100 includes a first lens 110, a second lens 120 and a third lens 130; The first lens 110 is a negative lens and the absolute value of its focal length is greater than 81mm, while the sum of the focal lengths of the second lens 120 and the third lens 130 is 0. A second lens group 200 is used to complement the aberrations of the first lens group 100. The second lens group 200 includes a cemented lens 220, which includes a sixth lens 211 and a seventh lens 211. The cemented lens 220 corrects spherical aberration and chromatic aberration through complementarity. The second lens group 200 is disposed on the image-side side of the first lens group 100; The second lens group 200 also includes a fifth lens 210; An aperture stop, wherein the aperture stop is coplanar with the object-side surface of the fifth lens 210; The second lens group 300 is disposed on the image side of the second lens group 200; Image plane, which is disposed on the image plane side of the second lens group 300.

[0024] In the optical system provided in this application embodiment, to solve the problem of excessively large light angles caused by a large 60-degree field of view and a large relative aperture, the present invention uses a first lens 110 of the first lens group 100 that is a negative lens, a second lens 120 that is a positive lens, and a third lens 130 that is a negative lens. Its main feature is that the absolute value of the focal length of the first lens 110 is particularly large and it is a negative lens. Furthermore, the sum of the focal lengths of the second lens 120 and the third lens 130 is approximately zero. Firstly, this design of the focal length of the first lens 110 effectively solves the problem of excessively large light angles caused by a large 60-degree field of view and a large relative aperture. It also effectively improves the situation where the aperture of the first lens group 100 in most large field-of-view lenses on the market is much larger than that of the subsequent lens groups. In addition, the design that the sum of the focal lengths of the second lens 120 and the third lens 130 is approximately zero effectively solves the problem of large size caused by excessively long axial length and excessively long air layers in large field-of-view objectives. It also solves the problem that the first lens group 100 generally uses materials with high refractive index, high density, and high price.

[0025] The design of the first lens group 100 of this invention achieves the following breakthroughs by rationally allocating the optical power of each lens within the first lens group 100: First, the first lens group 100 effectively smooths out the large-angle incident light from large-field-of-view, large-relative-aperture objectives through rational optical power allocation, effectively shortening the objective focal length, making the objective suitable for 1-inch large-scale target detectors, greatly reducing the #F number, and effectively increasing the light transmission of low-light objectives; second, it effectively balances the problem of excessively large mechanical aperture of the first lens group 100 for large-field-of-view, large-relative-aperture objectives, enabling the entire objective barrel to have a consistent aperture, effectively reducing the objective volume, and making it very suitable for miniaturized applications; third, it effectively shortens the axial length of the objective; fourth, it significantly reduces the overall mass of the objective; and fifth, it effectively reduces costs.

[0026] It is evident that the present invention significantly improves the objective lens performance through the design of the first lens group 100.

[0027] Furthermore, through the aberration complementarity between the first lens group 100 and the second lens group 200, the cemented lens 220 in the second lens group 200 corrects spherical aberration and chromatic aberration through complementary means, and the optical power of each lens is reasonably calculated to ensure no focal plane shift under high and low temperatures, achieving a day-and-night focus effect. It achieves high-quality pixels during the day while maintaining high-definition image quality at night or in low-light conditions. It also remains usable in environments with varying temperatures.

[0028] Meanwhile, the entire lens ensures a reasonable distribution of refractive index and optical power, and maintains a balance in the incident angles of the front and rear lens elements to avoid sensitive aberrations and reduce assembly difficulty. By rationally allocating the focal lengths of each lens element, the imaging system achieves minimal spherical aberration and field curvature, ensuring high image quality both on-axis and off-axis. This effectively solves the problem of poor image quality caused by the large field of view in existing large-aperture objective lens optical systems.

[0029] like Figure 1-5 As shown, the image plane size is a 1-inch low-light CMOS or CCD.

[0030] In this technical solution, CMOS stands for Complementary Metal-Oxide Semiconductor, which can be used as a photosensitive element in digital imaging equipment, while CCD stands for Charge-Coupled Device, which can also be used in digital photography.

[0031] like Figure 1-5 As shown, the first lens group 100 further includes a fourth lens 140, and the first lens 110, the second lens 120, the third lens 130 and the fourth lens 140 are arranged sequentially from the object side to the image side along the optical axis; The second lens 120 is a glass spherical lens with positive optical power, its object side is convex and its image side is concave. The third lens 130 is a glass spherical lens with negative optical power, its object side is concave, and its image side is concave. The fourth lens 140 is a glass spherical lens with negative optical power, its object side is concave and its image side is convex. The second lens group 300 includes an eighth lens 310 and a ninth lens 320, which are arranged sequentially from the object side to the image side along the optical axis; The eighth lens 310 is a glass spherical lens with positive optical power, its object side is convex, and its image side is convex. The ninth lens 320 is a glass spherical lens with positive optical power, its object side is concave and its image side is convex. The second lens group 200 includes a fifth lens 210 and a cemented lens 220, wherein the cemented lens 220 includes a sixth lens 211 and a seventh lens 211; The fifth lens 210 is a glass spherical lens with positive optical power, its object side is convex, and its image side is convex. The sixth lens 211 is a glass spherical lens with positive optical power, its object side is convex, and its image side is convex. The image side of the sixth lens 211 and the object side of the seventh lens 211 are bonded together with photosensitive adhesive. The seventh lens 211 is a glass spherical lens with negative optical power, and its object side is concave and its image side is concave.

[0032] like Figure 1-5 As shown, the first lens 110 satisfies -3.5 ≥ f A1 / Φ A1 ≥-4, where f A1 Φ represents the focal length of the first lens 110. A1 This indicates the effective aperture of the first lens 110; The second lens 120 satisfies 2≥f A2 / Φ A2 ≥1.5, where f A2 Indicates the focal length of the second lens 120; Φ A2 This indicates the effective aperture of the second lens 120; The third lens 130 satisfies -1.5 ≥ f A3 / Φ A3 ≥-2, where f A3 Indicates the focal length of the third lens 130; Φ A3 This indicates the effective aperture of the third lens 130; The fourth lens 140 satisfies -30≥f A4 / Φ A4 ≥-35, where f A4 Indicates the focal length of the fourth lens at 140°; Φ A4 This indicates the effective aperture of the fourth lens 140; The fifth lens 210 satisfies 1.5 ≥ f C1 / Φ C1 ≥1, where f C1 Φ represents the focal length of the fifth lens 210; C1 This indicates the effective aperture of the fifth lens 210; The sixth lens 211 satisfies 2≥f C2 / Φ C2 ≥1, where f C2 Φ represents the focal length of the sixth lens 211; C2 Indicates the effective aperture of the sixth lens 211; The eighth lens 310 satisfies 1.5 ≥ F. D1 / Φ D1 ≥1, where f D1 Indicates the focal length of the eighth lens 310; Φ D1 This indicates the effective aperture of the eighth lens 310; The ninth lens 320 satisfies -2≥f D2 / Φ D2 ≥-2.5, where f D2 Indicates the focal length of the ninth lens 320; Φ D2 This indicates the effective aperture of the seventh lens 211.

[0033] like Figure 1-5 As shown, the optical system composed of the first lens group 100, the second lens group 200, the aperture stop, and the second lens group 300 achieves the following optical specifications: wavelength range of 450nm to 1000nm; maximum field of view distortion of no more than -5%; pixel size of 800px × 600px; field of view range of 50° × 40°; diagonal field of view including distortion of 62°; and f / L greater than or equal to 0.3, where f represents the focal length of the objective lens and L represents the total optical length of the objective lens.

[0034] like Figure 1-5 As shown, the first lens 110 satisfies the relationships Nd≥1.8, Vd≥40, and -82mm. <f A1 <-81mm, f A1 The focal length of the first lens 110; The second lens 120 satisfies the relationships Nd≥1.7, Vd≥50, and 20mm. <f A2 <30mm, f A2 The focal length of the second lens 120; The third lens 130 satisfies the relationships Nd≥1.65, Vd≥50, and -27mm. <f A3 <-25mm, f A3 The focal length of the third lens is 130. The fourth lens 140 satisfies the relationships Nd≥1.7, Vd≥50, and -480mm. <f A4 <-475mm, f A4 The focal length of the fourth lens is 140. The fifth lens 210 satisfies the relationships Nd≥1.7, Vd≥50, and 20mm. <f C1 <25mm, f C1 The focal length of the fifth lens 210; The sixth lens 211 satisfies the relationships Nd≥1.7, Vd≥40, and 25mm. <f C2 <30mm, f C2The focal length of the sixth lens 211; The seventh lens 211 satisfies the relationships Nd≥1.8, Vd≥24, and -14mm. <f C3 <-13mm, f C3 The focal length of the seventh lens 211; The eighth lens 310 satisfies the relationships Nd≥1.8, Vd≥40, and 16mm. <f D1 <18mm, f D1 The focal length of the eighth lens 310; The ninth lens 320 satisfies the relationships Nd≥1.7, Vd≥45, and -36mm. <f D2 <-35mm, f D2 This is the focal length of the ninth lens, 320. Where Nd is the glass refractive index of the lens, and Vd is the glass Abbe number of the lens.

[0035] In this embodiment, the Nd value of the first lens 110 is specifically 1.8m. -1 The Vd value is specifically 40.9; The Nd value of the second lens 120 is specifically 1.72m. -1 The Vd value is specifically 50.3; The Nd value of the third lens 130 is specifically 1.65m. -1 The Vd value is specifically 58.4; The Nd value of the fourth lens 140 is specifically 1.75m. -1 The Vd value is specifically 52.3; The Nd value of the fifth lens 210 is specifically 1.81m. -1 The Vd value is specifically 46.5; The Nd value of the sixth lens 211 is specifically 1.71m. -1 The Vd value is specifically 47.9; The Nd value of the seventh lens 211 is specifically 1.85m. -1 The Vd value is specifically 24.8; The Nd value of the eighth lens 310 is specifically 1.85m. -1 The Vd value is specifically 40.76; The Nd value of the ninth lens 320 is specifically 1.75m. -1 The Vd value is specifically 47.7.

[0036] like Figure 1-5As shown, the first lens group 100, the second lens group 200, the aperture stop, and the second lens group 300 are all made of white glass; the first lens group 100, the second lens group 200, the aperture stop, and the third lens group 300 are all coated to a wavelength range of 450nm to 1000nm. Preferably, the lens coating satisfies that the average reflectance of vertically incident light is not greater than 1% in the range of 450nm to 1000nm, and the average reflectance of vertically incident light is not greater than 0.8% in the range of 500 to 850nm.

[0037] In the aforementioned technical solution of this invention, the optical system of this invention has high resolution, adopts a large relative aperture and wide band design, achieves day and night confocality, and has good imaging quality in extreme environments such as -30℃ to 50℃; it uses spherical lenses and environmentally friendly materials, resulting in low cost, simple assembly and adjustment, and easy mass production; through reasonable glass material matching and lens power distribution, the axial and lateral chromatic aberrations of the entire optical system are well corrected, and the reasonable surface design also effectively corrects the higher aberrations of the entire optical system. At the same time, the light incident angle of each mirror is small, resulting in excellent overall imaging quality of the system.

[0038] like Figure 1-5 As shown, the first lens has an object-side radius of curvature of 14.34 mm, a surface spacing of 1.33 mm, and an effective aperture of 23.1 mm; and an image-side radius of curvature of 11.25 mm, a surface spacing of 6.38 mm, and an effective aperture of 20.2 mm. The second lens has an object-side radius of curvature of 20.02 mm, a surface spacing of 3.66 mm, and an effective aperture of 18.8 mm; and an image-side radius of curvature of 673.7 mm, a surface spacing of 3.95 mm, and an effective aperture of 17.6 mm. The third lens has an object-side radius of curvature of -455.8 mm, a surface spacing of 0.5 mm, and an effective aperture of 17.2 mm; and an image-side radius of curvature of 18.25 mm, a surface spacing of 3.97 mm, and an effective aperture of 13.9 mm. The fourth lens has an object-side radius of curvature of -10.93 mm, a surface spacing of 3.85 mm, and an effective aperture of 14.8 mm; and an image-side radius of curvature of -13.19 mm, a surface spacing of 4.3 mm, and an effective aperture of 15.5 mm. The fifth lens has an object-side radius of curvature of 21.01 mm, a surface spacing of 0.1 mm, and an effective aperture of 15.7 mm. The image-side radius of curvature is -68.13 mm, the surface spacing is 3.66 mm, and the effective aperture is 15.0 mm. The object-side radius of curvature of the sixth lens is 16.52 mm, the surface spacing is 0.5 mm, and the effective aperture is 15.7 mm. The image-side radius of curvature is -17.42 mm, the surface spacing is 4.3 mm, and the effective aperture is 15.4 mm. The seventh lens has an object-side radius of curvature of -17.42 mm, a surface spacing of 4.3 mm, and an effective aperture of 15.4 mm; and an image-side radius of curvature of 12.89 mm, a surface spacing of 1.82 mm, and an effective aperture of 13.9 mm. The eighth lens has an object-side radius of curvature of 19.1 mm, a surface spacing of 1.2 mm, and an effective aperture of 14.3 mm; and an image-side radius of curvature of -54.02 mm, a surface spacing of 8.04 mm, and an effective aperture of 14.5 mm. The ninth lens has an object-side radius of curvature of -12.72 mm, a surface spacing of 2.8 mm, and an effective aperture of 14.2 mm. The image-side radius of curvature of the ninth lens is -25.6 mm, the surface spacing is 1.14 mm, and the effective aperture is 15.2 mm.

[0039] In this technical solution, Table 1 shows the parameter values ​​of each lens in the optical system embodiment of the present invention:

[0040] Table 1 Wherein, S1 is the object-side surface of the first lens 110; S2 is the image-side surface of the first lens 110; S3 is the object-side surface of the second lens 120; S4 is the image-side surface of the second lens 120; S5 is the object-side surface of the third lens 130; S6 is the image-side surface of the third lens 130; S7 is the aperture stop surface and is also the object-side surface of the fourth lens; S8 is the image-side surface of the fourth lens 140; S9 is the object-side surface of the fifth lens 210; and S10 is the image-side surface of the fifth lens 210. S11 is the object-side surface of the sixth lens 211; S12 is the image-side surface of the sixth lens 211. Since the sixth lens 211 and the seventh lens 212 are cemented doublets, S12 is also the object-side surface of the seventh lens 212; S13 is the image-side surface of the seventh lens 212; S14 is the object-side surface of the eighth lens 310; S15 is the image-side surface of the eighth lens 310; S16 is the object-side surface of the ninth lens 320; S17 is the image-side surface of the ninth lens 320.

[0041] In this invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0042] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0043] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A large field-of-view, large-aperture fixed-focus objective lens optical system, characterized in that: It consists of a first lens group, a second lens group, and a third lens group; The first lens group consists of a first lens, a second lens, a third lens, and a fourth lens; The first lens is a negative lens and the absolute value of its focal length is greater than 81mm, and the sum of the focal lengths of the second and third lenses is 0. The second lens group is used to complement the aberrations of the first lens group. The second lens group consists of a cemented lens and a fifth lens. The cemented lens consists of a sixth lens and a seventh lens. The cemented lens corrects spherical aberration and chromatic aberration through complementarity. The second lens group is disposed on the image-side side of the first lens group; An aperture stop, wherein the aperture stop is coplanar with the object-side surface of the fifth lens; A third lens group is disposed on the image-side surface of the second lens group; An image plane is disposed on the image plane side of the third lens group; The first lens, the second lens, the third lens, and the fourth lens are arranged sequentially from the object side to the image side along the optical axis; The first lens is a glass spherical lens with negative optical power, its object side is convex and its image side is concave; The second lens is a glass spherical lens with positive optical power, its object side is convex and its image side is concave; The third lens is a glass spherical lens with negative optical power, its object side is concave, and its image side is concave. The fourth lens is a glass spherical lens with negative optical power, its object side is concave and its image side is convex. The third lens group consists of an eighth lens and a ninth lens, which are arranged sequentially from the object side to the image side along the optical axis. The eighth lens is a glass spherical lens with positive optical power, its object side is convex, and its image side is convex. The ninth lens is a glass spherical lens with negative optical power, its object side is concave and its image side is convex. The fifth, sixth, and seventh lenses are arranged sequentially from the object side to the image side along the optical axis; The fifth lens is a glass spherical lens with positive optical power, its object side is convex, and its image side is convex. The sixth lens is a glass spherical lens with positive optical power, its object side is convex, and its image side is convex. The image side of the sixth lens and the object side of the seventh lens are bonded together with photosensitive adhesive. The seventh lens is a glass spherical lens with negative optical power, and its object side and image side are concave.

2. The large field-of-view, large aperture fixed-focus objective lens optical system according to claim 1, characterized in that: The image plane size is a 1-inch micro-light CMOS or CCD.

3. The large field-of-view, large aperture fixed-focus objective lens optical system according to claim 2, characterized in that: The first lens satisfies -3.5 ≥ f A1 / Φ A1 ≥-4, where f A1 Φ represents the focal length of the first lens. A1 Indicates the effective aperture of the first lens; The second lens satisfies 2≥f A2 / Φ A2 ≥1.5, where f A2 Φ represents the focal length of the second lens. A2 Indicates the effective aperture of the second lens; The third lens satisfies -1.5 ≥ f A3 / Φ A3 ≥-2, where f A3 Indicates the focal length of the third lens; Φ A3 Indicates the effective aperture of the third lens; The fourth lens satisfies -30≥f A4 / Φ A4 ≥-35, where f A4 Φ represents the focal length of the fourth lens. A4 Indicates the effective aperture of the fourth lens; The fifth lens satisfies 1.5 ≥ f C1 / Φ C1 ≥1, where f C1 Φ represents the focal length of the fifth lens. C1 Indicates the effective aperture of the fifth lens; The sixth lens satisfies 2≥f C2 / Φ C2 ≥1, where f C2 Φ represents the focal length of the sixth lens. C2 Indicates the effective aperture of the sixth lens; The eighth lens satisfies 1.5 ≥ F. D1 / Φ D1 ≥1, where f D1 Φ represents the focal length of the eighth lens. D1 Indicates the effective aperture of the eighth lens; The ninth lens satisfies -2≥f D2 / Φ D2 ≥-2.5, where f D2 Φ represents the focal length of the ninth lens. D2 This indicates the effective aperture of the ninth lens.

4. The large field-of-view, large aperture fixed-focus objective lens optical system according to claim 1, characterized in that: The optical system composed of the first lens group, the second lens group, the aperture stop, and the third lens group achieves optical parameters in the wavelength range of 450nm to 1000nm. The maximum distortion of the field of view is no greater than -5%; The pixel size is 800px × 600px; The field of view is 50° × 40°; The distorted diagonal field of view is 62°. f / L is greater than or equal to 0.3, where f represents the focal length of the objective lens and L represents the total optical length of the objective lens.

5. The large field-of-view, large aperture fixed-focus objective lens optical system according to claim 3, characterized in that: The first lens satisfies the relationships Nd≥1.8, Vd≥40, and -82mm. <f A1 <-81mm, f A1 The focal length of the first lens; The second lens satisfies the relationships Nd≥1.7, Vd≥50, and 20mm. <f A2 <30mm, f A2 The focal length of the second lens; The third lens satisfies the relationships Nd≥1.65, Vd≥50, and -27mm. <f A3 <-25mm, f A3 The focal length of the third lens; The fourth lens satisfies the relationships Nd≥1.7, Vd≥50, and -480mm. <f A4 <-475mm, f A4 This is the focal length of the fourth lens; The fifth lens satisfies the relationships Nd≥1.7, Vd≥50, and 20mm. <f C1 <25mm, f C1 The focal length of the fifth lens; The sixth lens satisfies the relationships Nd≥1.7, Vd≥40, and 25mm. <f C2 <30mm, f C2 The focal length of the sixth lens; The seventh lens satisfies the relationships Nd≥1.8, Vd≥24, and -14mm. <f C3 <-13mm, f C3 This is the focal length of the seventh lens; The eighth lens satisfies the relationships Nd≥1.8, Vd≥40, and 16mm. <f D1 <18mm, f D1 This is the focal length of the eighth lens; The ninth lens satisfies the relationships Nd≥1.7, Vd≥45, and -36mm. <f D2 <-35mm, f D2 This is the focal length of the ninth lens; Where Nd is the glass refractive index of the lens, and Vd is the glass Abbe number of the lens.

6. The large field-of-view, large aperture fixed-focus objective lens optical system according to claim 1, characterized in that: The first lens group, the second lens group, the aperture stop, and the third lens group are all made of white glass. The first lens group, the second lens group, the aperture, and the third lens group are all coated to a wavelength range of 450nm to 1000nm.

7. The large field-of-view, large aperture fixed-focus objective lens optical system according to claim 5, characterized in that: Both the sixth and ninth lenses are made of flint glass.

8. The large field-of-view, large aperture fixed-focus objective lens optical system according to claim 3, characterized in that: The second, third, and fourth lenses are made of crown glass.

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