High-image-quality projection lens and imaging method thereof

Abstract

The invention relates to a high-image-quality projection lens and an imaging method thereof, an optical system of the lens has 10 lenses with focal power, and the 10 lenses are sequentially a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens along the incident direction of an optical path, a diaphragm is arranged between the fifth lens and the sixth lens; the first lens is a meniscus negative lens; the second lens is a meniscus negative lens; the third lens is a meniscus negative lens; the fourth lens is a biconvex positive lens; the fifth lens is a meniscus positive lens; the sixth lens is a biconcave negative lens; the seventh lens is a biconvex positive lens; the eighth lens is a negative meniscus lens; the ninth lens is a biconvex positive lens; the tenth lens is a biconvex positive lens; all the lenses are made of glass materials, the second lens and the tenth lens are aspheric lenses, and the seventh lens and the eighth lens form a balsaming lens group.

Description

Technical Field

[0001] This invention relates to the field of lens technology, and in particular to a high-quality projection lens and its imaging method. Background Technology

[0002] In high-end projection scenarios such as automotive applications, existing lenses suffer from numerous drawbacks: poor temperature adaptability, with most having a narrow operating temperature range (e.g., -30℃ to 80℃), and prone to focus loss under extreme temperatures; focusing ranges are mostly concentrated between 20 and 40 inches, and some employ manual or semi-automatic focusing methods; bulky optical structures (over 80mm in total length and greater than 40mm in diameter), making them difficult to adapt to the compact spaces of vehicles; suboptimal image quality, with MTF, distortion, chromatic aberration, and edge illumination failing to meet high-end requirements; and insufficient automotive-grade reliability, with materials and protection levels unable to withstand harsh environments. Therefore, this invention aims to provide a high-quality projection lens to address these technical shortcomings and meet the stringent requirements of automotive and other similar scenarios. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a high-quality projection lens and its imaging method, which supports a focus range of 12 to 50 inches, does not lose focus when operating at a temperature of -40℃ to 85℃, and has a relatively compact size while achieving high-quality imaging.

[0004] This invention is achieved using the following scheme: a high-image-quality projection lens, wherein the optical system of the lens has 10 lenses with optical power, arranged sequentially along the incident light path as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens, with an aperture stop between the fifth and sixth lenses; the first lens is a meniscus negative lens, with its object-side surface being convex and its image-side surface being concave; the second lens is a meniscus negative lens, with its object-side surface being convex and its image-side surface being concave; the tenth lens... The third lens is a meniscus negative lens with a concave object side and a convex image side; the fourth lens is a biconvex positive lens; the fifth lens is a meniscus positive lens with a convex object side and a concave image side; the sixth lens is a biconcave negative lens; the seventh lens is a biconvex positive lens; the eighth lens is a meniscus negative lens with a concave object side and a convex image side; the ninth lens is a biconvex positive lens; and the tenth lens is a biconvex positive lens. All lenses are made of glass, with the second and tenth lenses being aspherical lenses, and the seventh and eighth lenses forming a cemented lens group.

[0005] Furthermore, the focal length of the optical system is f, and the focal lengths of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth lenses are f1, f2, f3, f4, f5, f6, f7, f8, f9, and f10, respectively. The ratios of f1, f2, f3, f4, f5, f6, f7, f8, f9, and f10 to f satisfy the following ratio: -2.0 <f1 / f<-1.0,-4.0<f2 / f<-3.0,-4.0<f3 / f<-3.0,2.0<f4 / f<3.0,2.0<f5 / f<3.0,-2.0<f6 / f<-1.0,1.0<f7 / f<2.0,-1.0<f8 / f<0.0,1.0<f9 / f<2.0,1.0<f10 / f<2.0。

[0006] Furthermore, the first lens satisfies the relationship: 1.7 ≤ N d ≤2.0, V d ≤50.0; The second lens satisfies the relationship: 1.4≤N d ≤1.7, V d ≥50.0; The third lens satisfies the relationship: 1.4≤N d ≤1.7, V d ≥50.0; The fourth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; The fifth lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; The sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; The seventh lens satisfies the relation: 1.4≤N d ≤1.7, V d ≥50.0; The eighth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; The ninth lens satisfies the relation: 1.4≤N d ≤1.7, V d ≥50.0; The tenth lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; where N d V is the refractive index. d Let be Abbe's constant.

[0007] Furthermore, the air gap between the first lens and the second lens is 3.5~4.0mm; the air gap between the second lens and the third lens is 5.0~5.5mm; the air gap between the third lens and the fourth lens is 0.1~0.5mm; the air gap between the fourth lens and the fifth lens is 0.1~0.5mm; the air gap between the fifth lens and the aperture stop is 19.0~19.5mm; the air gap between the aperture stop and the sixth lens is 2.5~3.0mm; the air gap between the sixth lens and the seventh lens is 0.1~0.5mm; the seventh lens and the eighth lens form a cemented lens group with an air gap of 0mm; the air gap between the eighth lens and the ninth lens is 0.5~1.0mm; and the air gap between the ninth lens and the tenth lens is 0.1~0.5mm.

[0008] Furthermore, the total optical length (TTL) of the optical system and the focal length (f) of the optical system satisfy the following condition: TTL / f ≤ 5.6.

[0009] Furthermore, the F-number of the optical system is ≤2.0.

[0010] Furthermore, the image height H of the optical system and the focal length f of the optical system satisfy the following condition: H / f ≥ 0.4.

[0011] Furthermore, a filter, a prism, and a glass plate are provided on the rear side of the tenth lens.

[0012] Another technical solution of the present invention: an imaging method for a high-image-quality projection lens as described above, wherein light passes sequentially through a first lens, a second lens, a third lens, a fourth lens, a fifth lens, an aperture stop, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, a filter, a prism, and a glass plate before forming an image.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) A symmetrical structure with the aperture placed at the center of the optical system is adopted to achieve ultra-low distortion design; through reasonable material combination, axial chromatic aberration, transverse chromatic aberration and higher-order chromatic aberration are corrected to ensure high imaging quality in the entire field of view; (2) The design of eight spherical lenses combined with two aspherical lenses can effectively correct various aberrations such as spherical aberration and coma, and can achieve high-quality imaging while meeting the focusing range of 12 to 50 inches. (3) It adopts an all-glass structure, which has high stability and can make good compensation for focal plane displacement at high and low temperatures, and has the adaptability to complex environments.

[0014] (4) Fully utilize the advantages of aspherical surfaces to reduce aberrations and further reduce the number of lenses. The total length of the first to tenth lenses is 73mm, effectively reducing the length of the lens. (5) By reasonably matching the optical lenses, the system structure is compact and reasonable, easy to assemble, has low tolerance sensitivity, and is more suitable for large-scale high-yield production; To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through specific embodiments and related drawings. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the optical system structure according to an embodiment of the present invention; Figure 2 This is an axial chromatic aberration diagram of the optical system across the entire operating band according to an embodiment of the present invention; Figure 3 This is a transverse chromatic aberration diagram of the optical system across the entire operating band according to an embodiment of the present invention; Figure 4 This is a field curvature distortion diagram of the optical system across all operating bands according to an embodiment of the present invention; In the diagram: STO - aperture stop; L1 - first lens; L2 - second lens; L3 - third lens; L4 - fourth lens; L5 - fifth lens; L6 - sixth lens; L7 - seventh lens; L8 - eighth lens; L9 - ninth lens; L10 - tenth lens; L11 - filter; L12 - prism; L13 - glass plate; IMA - imaging plane. Detailed Implementation

[0016] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0017] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0018] like Figure 1As shown, a high-resolution projection lens has an optical system comprising 10 lenses with optical power, arranged sequentially along the incident light path as a first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens, and tenth lens. An aperture stop is provided between the fifth and sixth lenses. Ignoring aspherical coefficient-induced curvature, the first lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface; the second lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface; the third lens is a meniscus negative lens with a concave object-side surface and a convex image-side surface; and the fourth lens is a biconvex positive lens. The first lens has a convex object-side surface and a convex image-side surface; the fifth lens is a meniscus positive lens with a convex object-side surface and a concave image-side surface; the sixth lens is a biconcave negative lens with a concave object-side surface and a concave image-side surface; the seventh lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface; the eighth lens is a meniscus negative lens with a concave object-side surface and a convex image-side surface; the ninth lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface; the tenth lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface; all lenses are made of glass, with the second and tenth lenses being aspherical lenses, and the seventh and eighth lenses forming a cemented lens group.

[0019] The second lens primarily performs early pre-correction of spherical aberration, while the tenth lens corrects coma and optimizes field curvature. The aperture stop is placed in the center of the system, employing a symmetrical structure to effectively reduce distortion. The seventh and eighth lenses form an achromatic cemented doublet. This rational lens arrangement allows the optical system to achieve a compact size, large aperture, and low temperature drift design, while effectively correcting on-axis and off-axis aberrations, resulting in good image quality. Figures 2 to 4 As shown.

[0020] In this embodiment, the focal length of the optical system is f, and the focal lengths of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens, and tenth lens are f1, f2, f3, f4, f5, f6, f7, f8, f9, and f10, respectively. The ratios of f1, f2, f3, f4, f5, f6, f7, f8, f9, and f10 to f satisfy the following ratio: -2.0 <f1 / f<-1.0,-4.0<f2 / f<-3.0,-4.0<f3 / f<-3.0,2.0<f4 / f<3.0,2.0<f5 / f<3.0,-2.0<f6 / f<-1.0,1.0<f7 / f<2.0,-1.0<f8 / f<0.0,1.0<f9 / f<2.0,1.0<f10 / f<2.0。

[0021] In this embodiment, the first lens satisfies the relationship: 1.7 ≤ N d≤2.0, V d ≤50.0; The second lens satisfies the relationship: 1.4≤N d ≤1.7, V d ≥50.0; The third lens satisfies the relationship: 1.4≤N d ≤1.7, V d ≥50.0; The fourth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; The fifth lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; The sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; The seventh lens satisfies the relation: 1.4≤N d ≤1.7, V d ≥50.0; The eighth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; The ninth lens satisfies the relation: 1.4≤N d ≤1.7, V d ≥50.0; The tenth lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; where N d V is the refractive index. d Let be Abbe's constant.

[0022] In this embodiment, the air gap between the first lens and the second lens is 3.5~4.0mm; the air gap between the second lens and the third lens is 5.0~5.5mm; the air gap between the third lens and the fourth lens is 0.1~0.5mm; the air gap between the fourth lens and the fifth lens is 0.1~0.5mm; the air gap between the fifth lens and the aperture stop is 19.0~19.5mm; the air gap between the aperture stop and the sixth lens is 2.5~3.0mm; the air gap between the sixth lens and the seventh lens is 0.1~0.5mm; the seventh lens and the eighth lens form a cemented lens group with an air gap of 0mm; the air gap between the eighth lens and the ninth lens is 0.5~1.0mm; and the air gap between the ninth lens and the tenth lens is 0.1~0.5mm.

[0023] In this embodiment, both the second and tenth lenses are aspherical lenses. The equation for the aspherical curve is:

[0024] Where z is the distance from the vertex of the aspherical surface to the optical axis at a position of height r; c is the paraxial curvature of the aspherical surface; and k is the conic constant. All are coefficients of higher-order terms.

[0025] The aspherical coefficients of the aspherical lenses in the optical system of this embodiment are shown in the table below:

[0026] In this embodiment, the total optical length (TTL) of the optical system and the focal length (f) of the optical system satisfy the following condition: TTL / f ≤ 5.6.

[0027] In this embodiment, the F-number of the optical system is ≤2.0.

[0028] In this embodiment, the image height H of the optical system and the focal length f of the optical system satisfy the following condition: H / f≥0.4.

[0029] In this embodiment, a filter, a prism, and a glass plate are disposed on the rear side of the tenth lens.

[0030] The technical specifications achieved by the optical system in this embodiment are as follows: (1) Focal length: 19.0 ≤ EFFL ≤ 20.0 mm; (2) Aperture F≤2.0; (3) Field of view: 2w ≥ 44°; (4) Focusing range: 12~50 inches (5) Operating band: Visible light band.

[0031] To achieve the above design parameters, the specific design of the optical system adopted in this embodiment is shown in the table below:

[0032] The optical system in this embodiment achieves high-quality imaging requirements while meeting a wide focusing range and operating temperature by rationally allocating the optical power, surface shape, center thickness of each lens, and on-axis distance between each lens, while also having a compact external structure.

[0033] An imaging method for a high-resolution projection lens as described above, wherein light passes sequentially through a first lens, a second lens, a third lens, a fourth lens, a fifth lens, an aperture stop, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, a filter, a prism, and a glass plate before forming an image.

[0034] Unless otherwise stated, if any of the technical solutions disclosed in this invention specify a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this invention discloses only some numerical values ​​to illustrate the technical solutions of this invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0035] If this invention discloses or relates to mutually fixedly connected components or structural parts, then, unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).

[0036] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0037] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A high-image-quality projection lens, characterized in that: The optical system of the lens comprises 10 lenses with optical power, arranged sequentially along the incident light path as a first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens, and tenth lens. An aperture stop is provided between the fifth and sixth lenses. The first lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface; the second lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface; the third lens is a meniscus negative lens with a concave object-side surface and a convex image-side surface; the fourth lens is a biconvex positive lens; the fifth lens is a meniscus positive lens with a convex object-side surface and a concave image-side surface; the sixth lens is a biconcave negative lens; the seventh lens is a biconvex positive lens; the eighth lens is a meniscus negative lens with a concave object-side surface and a convex image-side surface; the ninth lens is a biconvex positive lens; and the tenth lens is a biconvex positive lens. All lenses are made of glass, with the second and tenth lenses being aspherical lenses, and the seventh and eighth lenses forming a cemented lens group.

2. The high-image-quality projection lens according to claim 1, characterized in that: The focal length of the optical system is f. The focal lengths of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth lenses are f1, f2, f3, f4, f5, f6, f7, f8, f9, and f10, respectively. The ratios of f1, f2, f3, f4, f5, f6, f7, f8, f9, and f10 to f satisfy the following proportions: -2.0 < f1 / f < -1.0, -4.0 <f2 / f<-3.0,-4.0< f3 / f <-3.0,2.0<f4 / f <3.0,2.0< f5 / f <3.0,-2.0< f6 / f <-1.0,1.0< f7 / f <2.0,-1.0< f8 / f <0.0,1.0<f9 / f <2.0,1.0< f10 / f <2.0。 3. The high-image-quality projection lens according to claim 1, characterized in that: The first lens satisfies the relationship: 1.7 ≤ N d ≤2.0, V d ≤50.0; The second lens satisfies the relationship: 1.4≤N d ≤1.7, V d ≥50.0; The third lens satisfies the relationship: 1.4≤N d ≤1.7, V d ≥50.0; The fourth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; The fifth lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; The sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; The seventh lens satisfies the relation: 1.4≤N d ≤1.7, V d ≥50.0; The eighth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; The ninth lens satisfies the relation: 1.4≤N d ≤1.7, V d ≥50.0; The tenth lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; where N d V is the refractive index. d Let be Abbe's constant.

4. The high-quality projection lens according to claim 1, characterized in that: The air gap between the first and second lenses is 3.5~4.0mm; the air gap between the second and third lenses is 5.0~5.5mm; the air gap between the third and fourth lenses is 0.1~0.5mm; the air gap between the fourth and fifth lenses is 0.1~0.5mm; the air gap between the fifth lens and the aperture stop is 19.0~19.5mm; the air gap between the aperture stop and the sixth lens is 2.5~3.0mm; the air gap between the sixth and seventh lenses is 0.1~0.5mm; the seventh and eighth lenses form a cemented lens group with an air gap of 0mm; the air gap between the eighth and ninth lenses is 0.5~1.0mm; and the air gap between the ninth and tenth lenses is 0.1~0.5mm.

5. The high-image-quality projection lens according to claim 1, characterized in that: The total optical length (TTL) of an optical system and the focal length (f) of the optical system satisfy the following condition: TTL / f ≤ 5.

6.

6. The high-image-quality projection lens according to claim 1, characterized in that: The F-number of the optical system is ≤2.

0.

7. The high-image-quality projection lens according to claim 1, characterized in that: The image height H of the optical system and the focal length f of the optical system satisfy the following condition: H / f≥0.

4.

8. The high-image-quality projection lens according to claim 1, characterized in that: A filter, a prism, and a glass plate are provided on the rear side of the tenth lens.

9. An imaging method for a high-image-quality projection lens as described in claim 8, characterized in that: The light rays pass sequentially through the first lens, second lens, third lens, fourth lens, fifth lens, aperture, sixth lens, seventh lens, eighth lens, ninth lens, tenth lens, filter, prism and glass plate to form an image.

Images