Small projection lens

Abstract

The invention relates to a small projection lens, an optical system of the lens is composed of a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged from left to right along a light incident light path, and a diaphragm is arranged between the third lens and the fourth lens; the first lens is a biconvex positive lens, the second lens is a biconcave negative lens, the third lens is a plano-convex positive lens, the fourth lens is a meniscus negative lens, the fifth lens is a plano-convex positive lens, and the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all glass spherical lenses. The total length of the lens is smaller than 90 mm, the outer diameter is smaller than 40 mm, and the back focus is larger than 38 mm. The design is reasonable, the five glass spherical lenses form an imaging system, two of the glass spherical lenses are plano-convex lenses, and the cost is reduced while the system adapts to the environment; the imaging angle of the lens to an object is larger than 14 degrees, high image quality is achieved within the field angle range through reasonable matching of the positive lens and the negative lens, and the overall dimension is small.

Description

Technical Field

[0001] This invention belongs to the field of lens technology, and in particular relates to a small projection lens. Background Technology

[0002] With the rapid development of automotive intelligent technology, intelligent vehicle lighting systems, as a crucial component for enhancing driving safety and comfort, have become a research hotspot in the automotive industry. Intelligent vehicle lighting, through adaptive beam control, dynamic light pattern adjustment, and projection functions, can adjust the lighting mode in real time according to road conditions, weather, vehicle speed, and the surrounding environment, enabling functions such as high / low beam switching, anti-glare, road sign projection, and interactive light signal display. The projection lens, as the core optical component of the intelligent vehicle lighting system, is responsible for precisely shaping and projecting the beam emitted by a light source (such as an LED or laser) onto a designated area to form clear patterns, signs, or light fields, meeting functional lighting and visual interaction needs. The operating environment of intelligent vehicle lighting projection lenses is complex and demanding, requiring them to withstand extreme conditions during vehicle operation, including wide temperature ranges, strong vibrations, humidity, dust, and prolonged ultraviolet radiation. These factors necessitate lenses with excellent thermal stability, mechanical durability, anti-aging properties, and high optical transmittance to ensure accurate beam projection and clear patterns. Simultaneously, intelligent vehicle lighting systems emphasize miniaturization, lightweight design, and low power consumption to fit the compact installation space at the front of the vehicle and align with the trends of automotive lightweighting and energy efficiency optimization.

[0003] However, existing intelligent vehicle lighting projection lenses mostly employ an all-glass multi-element design or a simple single-lens structure, both of which suffer from drawbacks such as high manufacturing costs, heavy weight, high expenses, and insufficient durability. Therefore, a novel optical design is urgently needed to meet the diverse needs of intelligent vehicle lighting systems in autonomous driving and human-vehicle interaction. Summary of the Invention

[0004] The present invention addresses the problems existing in the prior art, namely, the technical problem to be solved by the present invention is to provide a small projection lens.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a small projection lens, wherein the optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially from left to right along the incident light path, and an aperture stop is provided between the third lens and the fourth lens; the first lens is a biconvex positive lens, the second lens is a biconcave negative lens, the third lens is a plano-convex positive lens, the fourth lens is a meniscus negative lens, and the fifth lens is a plano-convex positive lens, and the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all glass spherical lenses.

[0006] Furthermore, the object-side surface of the first lens is convex, and the image-side surface is convex; the object-side surface of the second lens is concave, and the image-side surface is concave; the object-side surface of the third lens is planar, and the image-side surface is convex; the object-side surface of the fourth lens is convex, and the image-side surface is concave; and the object-side surface of the fifth lens is convex, and the image-side surface is planar.

[0007] Furthermore, the on-axis distances between the lenses satisfy the following relationships: the air gap between the first lens and the second lens is 8.5–9.0 mm; the air gap between the second lens and the third lens is 11.0–11.5 mm; the air gap between the third lens and the aperture stop is 3.0–3.5 mm; the air gap between the aperture stop and the fourth lens is -3.5–-3.0 mm; and the air gap between the fourth lens and the fifth lens is 1.5–2.0 mm.

[0008] Furthermore, the focal length of the optical system is f, and the focal lengths of the first lens, second lens, third lens, fourth lens, and fifth lens are f1, f2, f3, f4, and f5, respectively, where f1, f2, f3, f4, and f5 satisfy the following ratio with f: 1.0 <f1 / f<2.0,-1.0<f2 / f<0.0,1.0<f3 / f<2.0,-2.0<f4 / f<-1.0,0.0<f5 / f<1.0。

[0009] Furthermore, the first lens satisfies the following relationship: 1.7≤Nd≤2.0, Vd≤50; the second lens satisfies the following relationship: 1.7≤Nd≤2.0, Vd≤50; the third lens satisfies the following relationship: 1.7≤Nd≤2.0, Vd≥50; the fourth lens satisfies the following relationship: 1.7≤Nd≤2.0, Vd≤50; and the fifth lens satisfies the following relationship: 1.7≤Nd≤2.0, Vd≥50; where Nd is the refractive index and Vd is the Abbe constant.

[0010] 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 ≤ 2.2.

[0011] Furthermore, the image height H of the optical system and the focal length f of the optical system satisfy the following condition: H / f≥0.1.

[0012] Furthermore, the F-number of the optical system is ≤1.3.

[0013] Furthermore, a sensor protective glass is provided on the right side of the fifth lens.

[0014] Furthermore, the lens has a total length of less than 90 mm, an outer diameter of less than 40 mm, and a back focal length of more than 38 mm.

[0015] Compared with the prior art, the present invention has the following advantages: The present invention is reasonably designed and consists of an imaging system composed of five glass spherical lenses, two of which are plano-convex lenses, which reduces costs while adapting to the environment; the imaging angle of the lens on the object is greater than 14 degrees, and by reasonably matching positive and negative lenses, high image quality is achieved within the field of view, and it has a small external size. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the optical structure of the present invention; Figure 2 This is the axial chromatic aberration diagram of the entire working band of the present invention; Figure 3 This is the transverse chromatic aberration diagram of the entire working band of the present invention; Figure 4 This is the field curvature distortion diagram of the entire working band of the present invention.

[0017] In the picture: STO - Aperture stop; L1 - First lens; L2 - Second lens; L3 - Third lens; L4 - Fourth lens; L5 - Fifth lens; CG - Sensor protective glass; IMA - Imaging surface. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0019] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0020] like Figure 1As shown, this invention discloses a small projection lens that achieves clear imaging while having a small size and low manufacturing cost. The optical system of the lens consists of a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5 arranged sequentially from left to right along the incident light path. An aperture stop STO is provided between the third lens L3 and the fourth lens L4. The first lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface. The second lens is a biconcave negative lens with a concave object-side surface and a concave image-side surface. The third lens is a plano-convex positive lens with a flat object-side surface and a convex image-side surface. The fourth lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface. The fifth lens is a plano-convex positive lens with a convex object-side surface and a flat image-side surface.

[0021] In this embodiment, each lens is made of glass, and the first lens, second lens, third lens, fourth lens and fifth lens are all glass spherical lenses.

[0022] In this embodiment, the on-axis distances between the lenses satisfy the following relationships: the air gap between the first lens and the second lens is 8.5 to 9.0 mm; the air gap between the second lens and the third lens is 11.0 to 11.5 mm; the air gap between the third lens and the aperture stop is 3.0 to 3.5 mm; the air gap between the aperture stop and the fourth lens is -3.5 to -3.0 mm; and the air gap between the fourth lens and the fifth lens is 1.5 to 2.0 mm.

[0023] 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, and fifth lens are f1, f2, f3, f4, and f5, respectively, wherein f1, f2, f3, f4, and f5 satisfy the following ratio with f: 1.0 <f1 / f<2.0,-1.0<f2 / f<0.0,1.0<f3 / f<2.0,-2.0<f4 / f<-1.0,0.0<f5 / f<1.0。

[0024] In this embodiment, the first lens satisfies the following relationship: 1.7≤Nd≤2.0, Vd≤50; the second lens satisfies the following relationship: 1.7≤Nd≤2.0, Vd≤50; the third lens satisfies the following relationship: 1.7≤Nd≤2.0, Vd≥50; the fourth lens satisfies the following relationship: 1.7≤Nd≤2.0, Vd≤50; and the fifth lens satisfies the following relationship: 1.7≤Nd≤2.0, Vd≥50; where Nd is the refractive index and Vd is the Abbe constant.

[0025] 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≤2.2.

[0026] 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≥0.1.

[0027] In this embodiment, the F-number of the optical system is ≤1.3.

[0028] In this embodiment, a sensor protective glass CG is provided on the right side of the fifth lens.

[0029] In this embodiment, the total length of the lens is less than 90 mm, the outer diameter is less than 40 mm, and the back focal length is greater than 38 mm. This ensures optical performance while reducing the overall size of the lens and provides sufficient space for subsequent mechanisms.

[0030] In this embodiment, the lens employs five optical elements, with the imaging system consisting of five glass spherical lenses. The use of glass spherical lenses, manufactured using mature technology, reduces production costs. By selecting suitable glass materials and allocating the optical power of each lens, the system's thermal stability is achieved under high and low temperature environments.

[0031] In this embodiment, the technical specifications achieved by the optical system are as follows: (1) Focal length: 42≤EFFL≤43mm; (2) Aperture F≤1.3; (3) Field of view: 2w ≥ 15°; (4) Back intercept: BFL ≥ 38 mm (including 0.7 mm CG); (5) Operating band: Visible light band.

[0032] To achieve the above design parameters, the specific design of the parameters of each lens in the optical system of this embodiment is shown in the table below.

[0033] The appropriate lens combination enables the optical system to achieve a small size, large aperture, and long back focal length, while effectively correcting on-axis and off-axis aberrations, resulting in good image quality. Figures 2 to 4 As shown.

[0034] In this embodiment, the optical system, by rationally allocating the optical power, surface shape, center thickness of each lens, and on-axis distance between each lens, meets the lens imaging performance requirements while reducing the overall length of the lens and the radial dimensions of each lens element, and ensures a longer back focal length, leaving space for subsequent mechanisms, thus achieving miniaturization of the lens assembly and reducing costs.

[0035] The advantages of this invention are: 1. This lens has an imaging angle of more than 14 degrees, and by properly matching positive and negative lenses, it achieves high image quality within the field of view. 2. By rationally matching the various 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; 3. Five glass lenses are used, two of which are plano-convex lenses, which reduces costs while adapting to the environment; 4. Axial chromatic aberration, transverse chromatic aberration, and higher-order chromatic aberration have been corrected to ensure that the imaging system has high imaging quality in all fields of view.

[0036] If this invention discloses or relates to components or structural parts that are fixedly connected to each other, then, unless otherwise stated, a fixed connection can be understood as: a fixed connection that can be detached (e.g., using bolts or screws), or a fixed connection that cannot be detached (e.g., riveting, welding). Of course, a fixed connection 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).

[0037] 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.

[0038] 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.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A compact projection lens characterized by: The optical system of the lens is composed of a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from left to right along the light path of the incident light, and a diaphragm is arranged between the third lens and the fourth lens; the first lens is a biconvex positive lens, the second lens is a biconcave negative lens, the third lens is a plano-convex positive lens, the fourth lens is a meniscus negative lens, and the fifth lens is a plano-convex positive lens; the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all glass spherical lenses.

2. The compact projection lens according to claim 1, characterized in that: The object side of the first lens is a convex surface, and the image side is a convex surface; the object side of the second lens is a concave surface, and the image side is a concave surface; the object side of the third lens is a plane, and the image side is a convex surface; the object side of the fourth lens is a convex surface, and the image side is a concave surface; and the object side of the fifth lens is a convex surface, and the image side is a plane.

3. The compact projection lens according to claim 1, characterized in that: The on-axis distance between each lens satisfies the following relationship: the air gap between the first lens and the second lens is 8.5-9.0 mm; the air gap between the second lens and the third lens is 11.0-11.5 mm; the air gap between the third lens and the diaphragm is 3.0-3.5 mm; the air gap between the diaphragm and the fourth lens is -3.5--3.0 mm; and the air gap between the fourth lens and the fifth lens is 1.5-2.0 mm.

4. The compact projection lens according to claim 1, characterized in that: The focal length of the optical system is f, and the focal lengths of the first lens, the second lens, the third lens, the fourth lens and the fifth lens are f1, f2, f3, f4 and f5 respectively, wherein f1, f2, f3, f4 and f5 satisfy the following ratios: 1.0 < f1 / f < 2.0, -1.0 < f2 / f < 0.0, 1.0 < f3 / f < 2.0, -2.0 < f4 / f < -1.0 and 0.0 < f5 / f < 1.

0.

5. The compact projection lens according to claim 1, characterized in that: The first lens satisfies the relationship: 1.7 ≤ Nd ≤ 2.0 and Vd ≤ 50; the second lens satisfies the relationship: 1.7 ≤ Nd ≤ 2.0 and Vd ≤ 50; the third lens satisfies the relationship: 1.7 ≤ Nd ≤ 2.0 and Vd ≥ 50; the fourth lens satisfies the relationship: 1.7 ≤ Nd ≤ 2.0 and Vd ≤ 50; and the fifth lens satisfies the relationship: 1.7 ≤ Nd ≤ 2.0 and Vd ≥ 50; wherein Nd is the refractive index and Vd is the Abbe number.

6. The compact projection lens according to claim 1, characterized in that: The total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f ≤ 2.

2.

7. The compact 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: H / f ≥ 0.

1.

8. The compact projection lens according to claim 1, characterized in that: The F number of the optical system is ≤1.

3.

9. The compact projection lens of claim 1, wherein: A sensor protection glass is arranged on the right side of the fifth lens.

10. The compact projection lens of claim 1, wherein: The total length of the lens is less than 90 mm, the outer diameter is less than 40 mm, and the back focus is greater than 38 mm.

Images