DMD welcome lamp lens with short total length

Abstract

The utility model relates to a DMD welcome lamp lens with short total length, the lens is composed of a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens and a seventh lens from left to right along a light incident light path, the lenses are made of glass materials, the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are glass spherical lenses, the second lens is a glass aspheric lens, wherein the third lens and the fourth lens, and the fifth lens and the sixth lens form a balsaming lens group. By reasonably distributing the focal power and the surface type of each lens, the central thickness of each lens, the axial distance between the lenses and the like, the imaging performance requirement of the lens is met, the total length of the lens and the radial size of each lens are reduced, and a 33 mm lens group is formed.

Description

Technical field:

[0001] The utility model relates to the technical field of lenses, in particular to a DMD welcome light lens with a short total length. Background technology:

[0002] Welcome lights and ground lights are a type of vehicle-mounted lamps. Their structure is a typical vehicle lamp structure, but they are mostly installed on the exterior rearview mirrors. Commonly used welcome light solutions are mostly solutions that use film. First, the light source is focused on the focal point of the LOGO, and then the light gathered through the LOGO film is diverged to achieve the effect of magnifying the LOGO; currently, the more widely used is PET-based film, which uses the imaging principle of film cameras to expose and imprint the LOGO pattern onto the film.

[0003] However, as users become younger and younger, the market is increasingly dissatisfied with solutions that can only project a single LOGO, and is looking forward to new solutions that can project different patterns or even dynamic videos. The welcome light solution based on the DMD projection system has emerged. However, due to its short object distance, high magnification ratio, low distortion and other requirements, it conflicts with the back focus distance that the DMD lighting system must reserve, making the total length of the lens of this solution often too large.

[0004] At present, the Chinese patent "A new type of automobile welcome light lens group structure" has been retrieved with publication number CN204176507U, which includes a light guide tube, a group of imaging lens groups are installed inside the light guide tube, and the imaging lens group is composed of three single-sided convex lenses, which are respectively a first single-sided convex mirror, a second single-sided convex mirror and a third single-sided convex mirror. A film clip is installed in the middle of the light guide tube, and a film picture is installed inside the film clip. The imaging lens group is located on the left side of the film picture clip, and the film picture clip is inserted into the light guide tube from top to bottom. An illumination focusing convex lens piece is installed in the light guide tube at the right end of the film picture clip. This patent can make the imaging more uniform, clear and full, has a simple structure, and can greatly reduce the volume of the entire lens assembly. However, there is a contradiction between this patent and the back focus distance required for the DMD lighting system, which often makes the total length of the lens too large. Summary of the invention:

[0005] In order to solve the above technical problems, the purpose of the utility model is to provide a DMD welcome light lens with a short total length. The DMD welcome light lens with a short total length and its working method are reasonably designed. Under the condition of short total length, they have a larger light aperture and lower tolerance sensitivity.

[0006] The technical solution of the utility model is: a DMD welcome light lens with a short total length, characterized in that: the optical system of the lens is composed of a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens and a seventh lens from left to right along the incident light path; the first lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the second lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the third lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the fourth lens is a meniscus convex positive lens, whose object side surface is convex , the image side surface is concave; the fifth lens is a double concave negative lens, whose object side surface is concave and the image side surface is concave; the sixth lens is a double convex positive lens, whose object side surface is convex and the image side surface is convex; the seventh lens is a double convex positive lens, whose object side surface is convex and the image side surface is convex; the lenses are made of glass material, the first, third, fourth, fifth, sixth and seventh lenses are glass spherical lenses, and the second lens is a glass aspherical lens, wherein the image side surface of the third lens is glued to the object side surface of the fourth lens to form a first glued lens group, and the image side surface of the fifth lens is glued to the object side surface of the sixth lens to form a second glued lens group.

[0007] Preferably, 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, the fifth lens, the sixth lens and the seventh lens are f1, f2, f3, f4, f5, f6, f7 respectively, wherein f1, f2, f3, f4, f5, f6, f7 and f satisfy the following ratio: -9.0 <f1 / f<-8.0,-6.0<f2 / f<-5.0,-2.0<f3 / f<-1.0,1.0<f4 / f<2.0,-1.0<f5 / f<0.0,1.0<f6 / f<2.0,3.0<f7 / f<4.0。

[0008] Preferably, the first lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; the second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the third lens satisfies the relationship: 1.7≤N d ≤2.0, 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 relationship: 1.7≤N d≤2.0, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

[0009] Preferably, the distances between the lenses on the optical axis satisfy the following relationship: the air gap between the first lens and the second lens is 3.5-4.0 mm; the air gap between the second lens and the third lens is 10.5-11.0 mm; the third lens and the fourth lens are a cemented lens group with an air gap of 0 mm; the air gap between the fourth lens and the aperture is 0.5-1.0 mm; the air gap between the aperture and the fifth lens is 0.1-0.5 mm; the fifth lens and the sixth lens are a cemented lens group with an air gap of 0 mm; the air gap between the sixth lens and the seventh lens is 0.1-0.5 mm.

[0010] Preferably, the total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤13.

[0011] Preferably, the F number of the optical system is ≤2.4.

[0012] Preferably, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≥1.0.

[0013] Compared with the prior art, the utility model has the following advantages:

[0014] 1. The imaging angle of the lens to the object is greater than 110 degrees, and it can project a 16.3cm wide picture at 8.5cm while ensuring TV Distortion <1%;

[0015] 2. With a total length of 33mm, it has the advantages of larger aperture, lower tolerance sensitivity and better high and low temperature stability;

[0016] 3. Through the reasonable matching of optical lenses, the system structure is compact and reasonable, easy to assemble, with low tolerance sensitivity, and more suitable for large-scale high-yield production;

[0017] 4. The all-glass structure has high stability and can adapt to harsh environments. It also gives full play to the advantages of aspherical lenses in correcting aberrations. While meeting high-definition imaging, it has a smaller lens outer diameter and shorter total optical length to ensure the miniaturization of the lens.

[0018] 5. Able to make good compensation for focal plane displacement at high and low temperatures, and have adaptability to complex environments;

[0019] 6. The axial chromatic aberration, vertical chromatic aberration and high-order chromatic aberration are corrected to ensure that the imaging system can have high imaging quality even at a large angle.

[0020] 7. Give full play to the advantages of aspherical lenses in correcting aberrations, meet the requirements of high-definition imaging, have a smaller lens outer diameter and a shorter total optical length, and ensure the miniaturization of the lens.

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Description of the drawings:

[0022] Figure 1 It is a schematic diagram of the optical structure of the utility model;

[0023] Figure 2 It is the axial chromatic aberration diagram of the full working band of the utility model;

[0024] Figure 3 It is the field curvature distortion diagram of the full working band of the utility model;

[0025] Figure 4 This is the MTF diagram of the full working band of the utility model;

[0026] In the figure: STO-aperture; L1-first lens; L2-second lens; L3-third lens; L4-fourth lens; L5-fifth lens; L6-sixth lens; L7-seventh lens; IMA-imaging surface. Specific implementation method:

[0027] The utility model is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0028] like Figure 1 As shown, the utility model is a DMD welcome light lens with a short total length. The optical system of the lens is composed of a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture, a fifth lens L5, a sixth lens L6 and a seventh lens L7 from left to right along the incident light path; the first lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the second lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the third lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the fourth lens is a meniscus convex positive lens, whose object side surface is The first lens is a convex surface, and the image side surface is concave; the fifth lens is a double concave negative lens, whose object side surface is concave and the image side surface is concave; the sixth lens is a double convex positive lens, whose object side surface is convex and the image side surface is convex; the seventh lens is a double convex positive lens, whose object side surface is convex and the image side surface is convex; the lenses are made of glass material, the first, third, fourth, fifth, sixth and seventh lenses are glass spherical lenses, and the second lens is a glass aspherical lens, wherein the image side surface of the third lens is glued to the object side surface of the fourth lens to form a first glued lens group, and the image side surface of the fifth lens is glued to the object side surface of the sixth lens to form a second glued lens group.

[0029] The first lens and the second lens are glass lenses with negative focal length, which can adjust large-angle light. The second lens is a glass aspherical lens, which has the function of reducing the distortion of the optical system. The third lens and the fourth lens, the fifth lens and the sixth lens form an achromatic doublet. Reasonable lens matching enables the optical system to achieve a total length of 33mm, wide angle, low distortion, low dispersion, large aperture, and low temperature drift design. At the same time, the on-axis and off-axis aberrations are well corrected, so that the lens has good imaging quality, such as Figures 2 to 4 shown.

[0030] 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, the fifth lens, the sixth lens and the seventh lens are f1, f2, f3, f4, f5, f6, f7 respectively, where f1, f2, f3, f4, f5, f6, f7 and f satisfy the following ratio: -9.0 <f1 / f<-8.0,-6.0<f2 / f<-5.0,-2.0<f3 / f<-1.0,1.0<f4 / f<2.0,-1.0<f5 / f<0.0,1.0<f6 / f<2.0,3.0<f7 / f<4.0。

[0031] The first lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; the second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the third lens satisfies the relationship: 1.7≤N d ≤2.0, 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 relationship: 1.7≤N d ≤2.0, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

[0032] The distances between the lenses on the optical axis satisfy the following relationship: the air gap between the first lens and the second lens is 3.5-4.0 mm; the air gap between the second lens and the third lens is 10.5-11.0 mm; the third lens and the fourth lens are a cemented lens group with an air gap of 0 mm; the air gap between the fourth lens and the aperture is 0.5-1.0 mm; the air gap between the aperture and the fifth lens is 0.1-0.5 mm; the fifth lens and the sixth lens are a cemented lens group with an air gap of 0 mm; the air gap between the sixth lens and the seventh lens is 0.1-0.5 mm.

[0033] The total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤13; the F number of the optical system ≤2.4; the image height H of the optical system and the focal length f of the optical system satisfy: H / f≥1.0.

[0034] The technical indicators achieved by the optical system of this utility model are as follows:

[0035] (1) Focal length: 2.0 ≤ EFFL ≤ 3.0 mm;

[0036] (2) Aperture F ≤ 2.4;

[0037] (3) Field of view: 2w ≥ 110°;

[0038] (4) Working band: visible light band.

[0039] To achieve the above design parameters, the specific design adopted by the optical system of this embodiment is shown in the following table:

[0040]

[0041]

[0042] The second lens is an aspheric lens, and the aspheric curve equation is expressed as:

[0043]

[0044] Among them, Z is the height of the aspheric surface from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis; c is the paraxial curvature of the aspheric surface; k is the cone constant; α1, α2, α3, α4, α5, α6, α7, and α8 are all high-order coefficients; the aspheric coefficients of the second lens are as follows:

[0045]

[0046] The optical system of this embodiment reduces the total length of the lens and the radial dimensions of each lens by reasonably allocating the optical power, surface shape, center thickness of each lens, and axial distance between each lens, while meeting the imaging performance requirements of the lens, so as to achieve a lens group with a total length of 33 mm.

[0047] The above is only the preferred embodiment of the utility model, and does not limit the utility model in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the utility model without departing from the technical solution of the utility model still belongs to the protection scope of the technical solution of the utility model.

Claims

1. A DMD welcome light lens with a short total length, characterized in that: The optical system of the lens is composed of a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens and a seventh lens from left to right along the incident light path; the first lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the second lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the third lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the fourth lens is a meniscus convex positive lens, whose object side surface is convex and whose image side surface is concave; the fifth lens is a double concave negative lens. The first lens is a double convex positive lens, whose object side surface is concave and whose image side surface is concave; the sixth lens is a double convex positive lens, whose object side surface is convex and whose image side surface is convex; the seventh lens is a double convex positive lens, whose object side surface is convex and whose image side surface is convex; the lenses are made of glass material, the first, third, fourth, fifth, sixth and seventh lenses are glass spherical lenses, and the second lens is a glass aspherical lens, wherein the image side surface of the third lens is glued to the object side surface of the fourth lens to form a first glued lens group, and the image side surface of the fifth lens is glued to the object side surface of the sixth lens to form a second glued lens group.

2. The DMD welcome light lens with a short total length 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, the fifth lens, the sixth lens and the seventh lens are f1, f2, f3, f4, f5, f6, f7 respectively, wherein f1, f2, f3, f4, f5, f6, f7 and f satisfy the following ratio: -9.0 <f1 / f<-8.0,-6.0<f2 / f<-5.0,-2.0<f3 / f<-1.0,1.0<f4 / f<2.0,-1.0<f5 / f<0.0,1.0<f6 / f<2.0,3.0<f7 / f<4.0。 3. The DMD welcome light lens with a short overall length 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: 1.5≤N d ≤1.8, V d ≥50.0; the third lens satisfies the relationship: 1.7≤N d ≤2.0, 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 relationship: 1.7≤N d ≤2.0, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

4. The DMD welcome light lens with a short total length according to claim 1, 2 or 3, characterized in that: The distances between the lenses on the optical axis satisfy the following relationship: the air gap between the first lens and the second lens is 3.5-4.0 mm; the air gap between the second lens and the third lens is 10.5-11.0 mm; the third lens and the fourth lens are a cemented lens group with an air gap of 0 mm; the air gap between the fourth lens and the aperture is 0.5-1.0 mm; the air gap between the aperture and the fifth lens is 0.1-0.5 mm; the fifth lens and the sixth lens are a cemented lens group with an air gap of 0 mm; the air gap between the sixth lens and the seventh lens is 0.1-0.5 mm.

5. The DMD welcome light lens with a short total length according to claim 1, 2 or 3, characterized in that: The total optical length TTL of the optical system and the focal length f of the optical system satisfy the following conditions: TTL / f≤13; and the F number of the optical system≤2.

4.

6. The DMD welcome light lens with a short total length according to claim 1, 2 or 3, characterized in that: The image height H of the optical system and the focal length f of the optical system satisfy: H / f≥1.

0.

7. The DMD welcome light lens with a short total length according to claim 1, 2 or 3, characterized in that: The technical indicators achieved by the optical system are as follows: (1) Focal length: 2.0 ≤ EFFL ≤ 3.0 mm; (2) Aperture F ≤ 2.4; (3) Field of view: 2w ≥ 110°; (4) Working band: visible light band.

Images