A short total length dmd welcome light lens and its working method

Abstract

The present application relates to a kind of short total length DMD welcome lamp lens and its working method, wherein short total length DMD welcome lamp lens is constituted by first lens, second lens, third lens, fourth lens, diaphragm, fifth lens, sixth lens and seventh lens from left to right along light path of light incidence, lens is made of glass material, first, third, fourth, fifth, sixth, seventh lens is glass spherical lens, second lens is glass aspherical lens, wherein third lens and fourth lens, fifth lens and sixth lens are cemented lens group. By reasonably distributing the optical power of each lens, surface type, the center thickness of each lens and the axial distance between each lens, etc., while meeting the imaging performance requirements of the lens, the total length of the lens and the radial dimension of each lens are reduced, achieving 33mm lens group.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lenses, in particular to a short total length DMD welcome light lens and a working method thereof. BACKGROUND

[0002] The welcome light and the ground light are a kind of vehicle-mounted lamps, and the structure thereof is a typical vehicle lamp structure. However, the installation position thereof is usually on the outside rearview mirror. A commonly used welcome light scheme is a scheme using a film, in which light from a light source is focused at a LOGO focal point, and then light passing through the LOGO film is dispersed to achieve the effect of magnifying the LOGO. Currently, a film of PET substrate is widely used, and the imaging and photographing principle of a film camera is used to expose the LOGO pattern to the film.

[0003] However, with the increasing youth of users, the market is increasingly dissatisfied with the scheme of being able to only project a single LOGO, and expects a new implementation scheme, that is, the scheme can project different patterns or even dynamic videos. A welcome light scheme based on a DMD projection system emerges as the times require. However, due to the requirements of short object distance, high magnification ratio, and low distortion, there is a contradiction with the back focal distance necessary for the DMD lighting system, so that the total length of the scheme lens is usually too large.

[0004] Currently, a Chinese patent "A novel automobile welcome light lens structure" (publication number CN204176507U) is searched, which comprises a light guide cylinder, a set of imaging lens groups is installed in the light guide cylinder, the imaging lens groups are composed of three single convex lenses, the three single convex lenses are a first single convex lens, a second single convex lens, and a third single convex lens, a film picture holder is installed at the middle of the light guide cylinder, a film picture is installed in the film picture holder, the imaging lens groups are located on the left side of the film picture holder, the film picture holder is inserted into the light guide cylinder from top to bottom, and an illumination condensing convex lens is installed in the light guide cylinder at the right side end of the film picture holder. The 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, in the patent, there is a contradiction with the back focal distance necessary for the DMD lighting system, so that the total length of the lens is usually too large. SUMMARY

[0005] In order to solve the above technical problems, the purpose of the present application is to provide a short total length DMD welcome light lens and a working method thereof, which are reasonable in design, have a larger light aperture and a lower tolerance sensitivity under the condition of short total length.

[0006] The technical scheme of the present application is: a short total length DMD welcome light lens, characterized in that: the optical system of the lens is sequentially 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 along the light path from left to right; the first lens is a meniscus concave negative lens, the object side is convex, and the image side is concave; the second lens is a meniscus concave negative lens, the object side is convex, and the image side is concave; the third lens is a meniscus concave negative lens, the object side is convex, and the image side is concave; the fourth lens is a meniscus convex positive lens, the object side is convex, and the image side is concave; the fifth lens is a double concave negative lens, the object side is concave, and the image side is concave; the sixth lens is a double convex positive lens, the object side is convex, and the image side is convex; the seventh lens is a double convex positive lens, the object side is convex, and the image side 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; the image side of the third lens and the object side of the fourth lens are glued to form a first glued lens group, and the image side of the fifth lens and the object side of the sixth lens are glued 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 and f7 respectively, wherein f1, f2, f3, f4, f5, f6 and f7 satisfy the following ratios: -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, and 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; and the seventh lens satisfies the relationship: 1.7 ≤ N d≤ 2.0, V d ≤ 50.0; wherein N d is the refractive index, V d is the Abbe number.

[0009] Preferably, the distance between each lens on the optical axis satisfies 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 cemented lens groups, and the air gap is 0 mm; the air gap between the fourth lens and the diaphragm is 0.5-1.0 mm; the air gap between the diaphragm and the fifth lens is 0.1-0.5 mm; the fifth lens and the sixth lens are cemented lens groups, and the air gap is 0 mm; and 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 present application has the following advantages:

[0014] 1. The lens has an imaging angle of an object of greater than 110 degrees, can project a 16.3 cm wide picture at 8.5 cm, and ensures that the TV distortion is less than 1%;

[0015] 2. Under the condition of a total length of 33 mm, the lens has a large light aperture, low tolerance sensitivity, and good high and low temperature stability;

[0016] 3. 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;

[0017] 4. The lens adopts a full glass structure, has high stability, can adapt to harsh environments, fully utilizes the advantages of aspherical lenses in correcting aberrations, meets the requirements of high-definition imaging, has a smaller lens outer diameter and shorter total optical length, and ensures the miniaturization of the lens.

[0018] 5. The lens can make good compensation for the focusing surface displacement at high and low temperatures, and has complex environment adaptability;

[0019] 6. The lens corrects the axial color difference, the sagittal color difference, and the high-order color difference, and ensures that the imaging system also has high imaging quality at a large angle.

[0020] 7. Fully leverage the advantages of aspherical lenses in correcting aberrations, achieving high-definition imaging while featuring a smaller lens outer diameter and shorter overall optical length, ensuring lens miniaturization.

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached image description:

[0022] Figure 1 This is a schematic diagram of the optical structure of the present invention;

[0023] Figure 2 This is the axial chromatic aberration diagram of the entire working band of the present invention;

[0024] Figure 3 This is the field curvature distortion diagram of the entire working band of the present invention;

[0025] Figure 4 This is the MTF chart of the entire operating band of this invention;

[0026] 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; IMA - imaging plane. Detailed implementation method:

[0027] The present invention will be further described below with reference to the accompanying drawings and specific implementation methods.

[0028] like Figure 1 As shown, this invention discloses a short-total-length DMD welcome light lens. The optical system of the lens, incident along the light path from left to right, consists of a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture stop, a fifth lens L5, a sixth lens L6, and a seventh lens L7. 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 convex object-side surface and a concave image-side surface; and the fourth lens is a meniscus positive lens with a convex object-side surface and a convex image-side surface. The first, third, fourth, fifth, sixth, and seventh lenses are spherical glass lenses, and the second lens is an aspherical glass lens. The image-side surface of the third lens is cemented with the object-side surface of the fourth lens to form the first cemented lens group, and the image-side surface of the fifth lens is cemented with the object-side surface of the sixth lens to form the second cemented lens group.

[0029] The first lens and the second lens are glass lenses with negative focal length, capable of adjusting large-angle light, wherein the second lens is a glass aspheric lens, which has the effect of reducing the distortion of the optical system; the third lens and the fourth lens, and the fifth lens and the sixth lens form achromatic double cemented lenses; reasonable lens matching makes the optical system realize 33mm total length, wide angle, low distortion, low dispersion, large aperture, low temperature drift design, and at the same time, on-axis and off-axis aberrations are well corrected, so that the lens has good imaging quality, as shown in Figures 2 to 4 .

[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 and f8 respectively, wherein f1, f2, f3, f4, f5, f6, f7 and f satisfy the following ratios: -9.0

[0031] The first lens satisfies the relationship: 1.7 d ≤2.0, V d ≤50.0; the second lens satisfies the relationship: 1.5 d ≤1.8, V d ≥50.0; the third lens satisfies the relationship: 1.7 d ≤2.0, V d ≤50.0; the fourth lens satisfies the relationship: 1.5 d ≤1.8, V d ≤50.0; the fifth lens satisfies the relationship: 1.7 d ≤2.0, V d ≤50.0; the sixth lens satisfies the relationship: 1.5 d ≤1.8, V d ≥50.0; the seventh lens satisfies the relationship: 1.7 d ≤2.0, V d ≤50.0; wherein N d is the refractive index, and V d is the Abbe number.

[0032] The distance between each lens on the optical axis satisfies the following relationship, 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: 10.5-11.0mm; the third lens and the fourth lens are cemented lens groups, the air gap is 0mm; the air gap between the fourth lens and the diaphragm is: 0.5-1.0mm; the air gap between the diaphragm and the fifth lens is: 0.1-0.5mm; the fifth lens and the sixth lens are cemented lens groups, the air gap is 0mm; the air gap between the sixth lens and the seventh lens is: 0.1-0.5mm.

[0033] The optical total 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 is ≤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 index realized by the optical system of the application is as follows:

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

[0036] (2) aperture F≤2.4;

[0037] (3) field of view angle: 2w≥110°;

[0038] (4) working waveband: visible light waveband.

[0039] In order to realize the above design parameters, the specific design of the optical system of the embodiment is as follows:

[0040]

[0041]

[0042] The second lens is a non-spherical lens, and the non-spherical curve equation expression is:

[0043]

[0044] Wherein, Z is the sagittal height of the non-spherical surface at a height of r along the optical axis direction from the vertex of the non-spherical surface; c is the paraxial curvature of the non-spherical surface; k is the conic constant; α1, α2, α3, α4, α5, α6, α7, α8 are all high-order coefficients; the non-spherical surface coefficients of the second lens are as follows:

[0045]

[0046] The optical system of the embodiment can meet the imaging performance requirements of the lens, and can reduce the total length of the lens and the radial size of each lens by reasonably distributing the focal power, surface shape, central thickness of each lens, and the axial distance between each lens.

[0047] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any skilled person in the art can modify or change the above disclosed technical content into equivalent embodiments. However, any simple modification, equivalent change and modification of the above embodiments without departing from the technical solution of the present application, and according to the technical essence of the present application, still belong to the protection scope of the technical solution of the present application.

Claims

1. A short total length DMD welcome light lens characterized by: The optical system of the lens is sequentially 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 along an optical path from left to right; the first lens is a meniscus concave negative lens, the object side surface of which is a convex surface and the image side surface of which is a concave surface; the second lens is a meniscus concave negative lens, the object side surface of which is a convex surface and the image side surface of which is a concave surface; the third lens is a meniscus concave negative lens, the object side surface of which is a convex surface and the image side surface of which is a concave surface; the fourth lens is a meniscus convex positive lens, the object side surface of which is a convex surface and the image side surface of which is a concave surface; the fifth lens is a double concave negative lens, the object side surface of which is a concave surface and the image side surface of which is a concave surface; the sixth lens is a double convex positive lens, the object side surface of which is a convex surface and the image side surface of which is a convex surface; the seventh lens is a double convex positive lens, the object side surface of which is a convex surface and the image side surface of which is a convex surface; the lenses are made of glass material, the first, third, fourth, fifth, sixth and seventh lenses are glass spherical surface lenses, and the second lens is a glass aspherical surface lens; the image side surface of the third lens and the object side surface of the fourth lens are cemented to form a first cemented lens group, and the image side surface of the fifth lens and the object side surface of the sixth lens are cemented to form a second cemented lens group; the focal length of the optical system is f, and the focal lengths of the first, second, third, fourth, fifth, sixth and seventh lenses are f1, f2, f3, f4, f5, f6 and f7 respectively, wherein f1, f2, f3, f4, f5, f6, f7 and f satisfy the following ratios: -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; 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; wherein N d is the refractive index and V d is the Abbe number.

2. The short-tfl DMD welcome lamp lens according to claim 1, characterized in that: The distance between the lenses on the optical axis satisfies 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, the air gap is 0 mm; the air gap between the fourth lens and the diaphragm is 0.5-1.0 mm; the air gap between the diaphragm and the fifth lens is 0.1-0.5 mm; the fifth lens and the sixth lens are a cemented lens group, the air gap is 0 mm; the air gap between the sixth lens and the seventh lens is 0.1-0.5 mm.

3. A short-tfl DMD welcome lamp lens according to claim 1 or 2, characterized in that: 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 is ≤2.

4.

4. The short-tfl DMD welcome lamp lens according to claim 1 or 2, 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.

5. The short-tfl DMD welcome lamp lens according to claim 1 or 2, 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 angle: 2w≥110°; (4) working waveband: visible light waveband.

6. A short-tfl DMD welcome lamp lens according to claim 1 or 2, characterized in that: The specific parameters adopted by the optical system are as follows:

7. The short total length DMD welcome light lens according to claim 1 or 2, characterized in that: the second lens is a non-spherical lens, and the non-spherical curve equation expression is: wherein Z is the sagittal height of the non-spherical surface at a height of r along the optical axis; c is the paraxial curvature of the non-spherical surface; k is the conic constant; α1, α2, α3, α4, α5, α6, α7, and α8 are high-order coefficients; the non-spherical surface coefficients of the second lens are as follows:

8. A method of operating a short total track length DMD spotlight lens as claimed in any one of claims 1 to 7, characterized by: The optical system of the short total length DMD welcome light lens sequentially comprises, from left to right along the optical path, a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, and a seventh lens; the first lens is a meniscus concave negative lens, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; the second lens is a meniscus concave negative lens, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; the third lens is a meniscus concave negative lens, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; the fourth lens is a meniscus convex positive lens, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; the fifth lens is a double concave negative lens, the object side surface of which is a concave surface, and the image side surface of which is a concave surface; the sixth lens is a double convex positive lens, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; the seventh lens is a double convex positive lens, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; the lenses are made of glass material, the first, third, fourth, fifth, sixth, and seventh lenses are glass spherical surface lenses, and the second lens is a glass non-spherical surface lens; the image side surface of the third lens and the object side surface of the fourth lens are cemented to form a first cemented lens group, and the image side surface of the fifth lens and the object side surface of the sixth lens are cemented to form a second cemented lens group; when light is incident, the light sequentially enters the first lens, the second lens, the third lens, the fourth lens, the diaphragm, the fifth lens, the sixth lens, and the seventh lens along the optical path, and forms an image on the IMA imaging surface.

Images