A welcome light lens suitable for a DMD imaging system and an imaging method thereof

Abstract

The application relates to a welcome light lens suitable for a DMD imaging system and an imaging method thereof. The optical system is composed of a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens and an eighth lens. The first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a meniscus concave 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, and the eighth lens is a biconvex positive lens. The third lens and the fourth lens are a cemented lens group, the sixth lens and the seventh lens are a cemented lens group, the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are all glass spherical lenses, and the second lens is a glass aspherical lens. The lens can image an object at an angle greater than 110 degrees, can project a 45cm-wide picture at a distance of 25cm, and can ensure that TV Distortion is less than 1%.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lenses, and particularly relates to a welcome light lens suitable for a DMD imaging system and an imaging method thereof. BACKGROUND

[0002] The welcome light is used to increase the high-tech sense of a vehicle and improve the commodity nature of a product, and is generally used in a high-end vehicle with a top configuration. A common welcome light scheme is a scheme using a film, because the LOGO needs to be projected on the ground, the first step is to focus the light of a light source at the focal point of the LOGO, and the second step is to disperse the light passing through the film of the LOGO to achieve the effect of magnifying the LOGO. A film of PET substrate is widely used, and the imaging principle of a film camera is used to expose the LOGO pattern to the film. The earliest welcome light of an outside rearview mirror used by Guangzhou Passenger Vehicle is a certain vehicle model, and is favored by a large number of customers after application, greatly improving the use experience of users. However, as users are increasingly young, the market is increasingly dissatisfied with the scheme of only projecting a single LOGO, and expects a new implementation scheme that can project different patterns or even dynamic videos. SUMMARY

[0003] The application improves the prior art, and the technical problem to be solved by the application is to provide a welcome light lens suitable for a DMD imaging system and an imaging method thereof.

[0004] In order to achieve the above purpose, the technical scheme adopted by the application is as follows: a welcome light lens suitable for a DMD imaging system, an optical system of 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, a seventh lens and an eighth lens arranged in sequence from left to right along the light incident path, the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a meniscus concave negative lens, the fourth lens is a double-convex positive lens, the fifth lens is a meniscus positive lens, the sixth lens is a double-concave negative lens, the seventh lens is a double-convex positive lens, the eighth lens is a double-convex positive lens, the third lens and the fourth lens are glued to form a first glued lens group, the sixth lens and the seventh lens are glued to form a second glued lens group, the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are all glass spherical lenses, and the second lens is a glass aspherical lens.

[0005] Further, the object side surface of the first lens is convex, the image side surface is concave; the object side surface of the second lens is convex, the image side surface is concave; the object side surface of the third lens is convex, the image side surface is concave; the object side surface of the fourth lens is convex, the image side surface is convex; the object side surface of the fifth lens is concave, the image side surface is convex; the object side surface of the sixth lens is concave, the image side surface is concave; the object side surface of the seventh lens is convex, the image side surface is convex; the object side surface of the eighth lens is convex, the image side surface is convex.

[0006] Further, the focal length of the optical system is f, the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are f1, f2, f3, f4, f5, f6, f7, f8 respectively, wherein f1, f2, f3, f4, f5, f6, f7, f8 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, 8.0 < f5 / f < 9.0, -6.0 < f6 / f < -5.0, 5.0 < f7 / f < 6.0, 6.0 < f8 / f < 7.0.

[0007] Further, the first lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; the second lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, 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: 1.5 ≤ N d ≤ 1.8, V d ≤ 50.0; the sixth lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; the seventh lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the eighth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≤ 50.0; wherein N d is the refractive index, V d is the Abbe number.

[0008] Further, the on-axis distance between each lens satisfies the following relationship, the air gap between the first lens and the second lens is: 4.1-4.5mm; the air gap between the second lens and the third lens is: 11.1-11.5mm; the air gap between the fourth lens and the diaphragm is: 3.1-3.5mm; the air gap between the diaphragm and the fifth lens is: 5.1-5.5mm; the air gap between the fifth lens and the sixth lens is: 0.0-0.5mm; the air gap between the seventh lens and the eighth lens is: 0.0-0.5mm.

[0009] Further, the optical total length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤20.

[0010] Further, the F number of the optical system is ≤1.8.

[0011] Further, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≥1.0.

[0012] Another technical solution adopted by the present application is: an imaging method of a welcome light lens suitable for a DMD imaging system, when imaging, the light path sequentially enters the first lens, the second lens, the third lens, the fourth lens, the diaphragm, the fifth lens, the sixth lens, the seventh lens and the eighth lens to perform imaging.

[0013] Compared with the prior art, the present application has the following effects: the present application is reasonable in design, the imaging angle of the lens to the object is greater than 110 degrees, a 45cm wide picture can be projected at 25cm while ensuring that TV Distortion<1%; it has the advantages of large light aperture, low tolerance sensitivity and good high-low temperature stability; the structure is compact and reasonable, easy to assemble, low tolerance sensitivity, more suitable for large-scale high-yield production. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is the optical structure schematic diagram of the embodiment of the present application;

[0015] Figure 2 is the full working waveband axial chromatic aberration diagram of the embodiment of the present application;

[0016] Figure 3 is the full working waveband field curvature distortion diagram of the embodiment of the present application;

[0017] Figure 4 is the full working waveband MTF diagram of the embodiment of the present application.

[0018] 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; IMA - imaging plane. Detailed implementation method:

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] like Figure 1 As shown, this invention provides a welcome light lens suitable for a DMD imaging system. The optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, an aperture stop, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from left to right along the incident light path. Without considering the curvature caused by the aspherical coefficient, 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, and the eighth lens is a biconvex positive lens. The third and fourth lenses are cemented together to form a first cemented lens group, and the sixth and seventh lenses are cemented together to form a second cemented lens group. The lenses are made of glass material; the first, third, fourth, fifth, sixth, seventh, and eighth lenses are all spherical glass lenses, and the second lens is a glass aspherical lens.

[0021] In this embodiment, the object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the second lens is convex, and the image-side surface is concave; the object-side surface of the third lens is convex, and the image-side surface is concave; the object-side surface of the fourth lens is convex, and the image-side surface is convex; the object-side surface of the fifth lens is concave, and the image-side surface is convex; the object-side surface of the sixth lens is concave, and the image-side surface is concave; the object-side surface of the seventh lens is convex, and the image-side surface is convex; and the object-side surface of the eighth lens is convex, and the image-side surface is convex.

[0022] 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, and eighth lens are f1, f2, f3, f4, f5, f6, f7, and f8, respectively. The ratios of f1, f2, f3, f4, f5, f6, f7, and f8 to 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<2.0,8.0<f5 / f<9.0,-6.0<f6 / f<-5.0,5.0<f7 / f<6.0,6.0<f8 / f<7.0。

[0023] In this embodiment, the first lens satisfies the relationship: 1.7 ≤ Nd ≤ 2.0, V d ≤ 50.0; the second lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, 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: 1.5 ≤ N d ≤ 1.8, V d ≤ 50.0; the sixth lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; the seventh lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the eighth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≤ 50.0; wherein N d is the refractive index, and V d is the Abbe number.

[0024] In this embodiment, the on-axis distance between each lens satisfies the following relationship, the air gap between the first lens and the second lens is: 4.1-4.5mm; the air gap between the second lens and the third lens is: 11.1-11.5mm; the air gap between the fourth lens and the diaphragm is: 3.1-3.5mm; the air gap between the diaphragm and the fifth lens is: 5.1-5.5mm; the air gap between the fifth lens and the sixth lens is: 0.0-0.5mm; the air gap between the seventh lens and the eighth lens is: 0.0-0.5mm.

[0025] In this embodiment, the total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f ≤ 20.

[0026] In this embodiment, the F number of the optical system is ≤ 1.8.

[0027] In this embodiment, the image height H of the optical system and the focal length f of the optical system satisfy: H / f ≥ 1.0.

[0028] In this embodiment, the aspheric surface curve equation expression of the second lens is:

[0029]

[0030] Wherein, Z is the sagittal height of the aspherical surface from the vertex of the aspherical surface at a position with a height of r along the optical axis; c is the paraxial curvature of the aspherical surface; k is the conic constant; and a1, a2, a3, a4, a5, a6, a7, and a8 are high-order coefficients.

[0031] Specifically, the aspherical surface coefficients of the aspherical lens are as shown in the following table.

[0032]

[0033] In the embodiment, the first lens and the second lens are both glass lenses with negative optical power, which can adjust large-angle light, and the glass aspherical surface also has the effect of reducing the distortion of the optical system. The third lens and the fourth lens, and the sixth lens and the seventh lens form an achromatic double cemented lens. Reasonable lens matching enables the optical system to achieve wide-angle, low-distortion, low-dispersion, large-aperture, low-temperature drift design, and simultaneously corrects on-axis and off-axis aberrations well, so that the lens has good imaging quality, as shown in FIG. 1. Figures 2 to 4 The technical indicators achieved by the optical system are as follows:

[0034] (1) focal length: 2.0≤EFFL≤3.0mm;

[0035] (2) aperture: F≤1.8;

[0036] (3) field of view: 2w≥110°;

[0037] (4) working waveband: visible light waveband.

[0038] To achieve the above design parameters, the specific design of the optical system of the embodiment is shown in the following table:

[0039]

[0040] In the embodiment, when the welcome light lens suitable for a DMD imaging system is imaging, the light path sequentially enters the first lens, the second lens, the third lens, the fourth lens, the diaphragm, the fifth lens, the sixth lens, the seventh lens, and the eighth lens for imaging.

[0041] The optical system of the embodiment, by reasonably allocating the optical power, surface shape, central thickness of each lens, and on-axis distance between each lens, etc., can not only meet the imaging performance requirements of the lens, but also reduce the total length of the lens and the radial size of each lens, achieving miniaturization of the lens group.

[0042] The present application has the following advantages:

[0043] 1. The lens has an imaging angle of an object of more than 110 degrees, and can project a 45cm-wide picture at a distance of 25cm while ensuring that the TV Distortion is less than 1%;

[0044] 2. It has the advantages of large light aperture, low tolerance sensitivity and good high and low temperature stability;

[0045] 3. By reasonably matching each optical lens, the system structure is compact and reasonable, easy to assemble, low in tolerance sensitivity, and more suitable for large-scale high-yield production;

[0046] 4. The full glass structure has high stability, can adapt to harsh environments, fully utilizes the advantages of aspheric lens in correcting aberration, meets high-definition imaging, has smaller lens outer diameter and shorter optical total length, and ensures miniaturization of the lens;

[0047] 5. It can make good compensation for the focusing surface displacement at high and low temperatures, and has complex environment adaptability;

[0048] 6. Each axial chromatic aberration, sagittal chromatic aberration and high-order chromatic aberration is corrected, so that the imaging system can also have high imaging quality at a large angle;

[0049] 7. The advantages of aspheric lens in correcting aberration are fully utilized, high-definition imaging is met, the lens has smaller lens outer diameter and shorter optical total length, and miniaturization of the lens is ensured.

[0050] If the present application discloses or involves mutually fixed connecting parts or structural parts, except otherwise stated, the fixed connection can be understood as: detachable fixed connection (for example, using bolt or screw connection), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, using casting process to integrally form and manufacture), except obviously cannot use integral forming process.

[0051] In addition, the terms used to represent the position relationship or shape in any of the technical solutions disclosed in the present application include the approximate, similar or close state or shape, unless otherwise stated.

[0052] Any component provided by the present application can be assembled from multiple individual components, or can be a single component manufactured by integral forming process.

[0053] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range of the present application claimed.

Claims

1. A welcome light lens suitable for a DMD imaging system, characterized in that: The optical system of 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, a seventh lens and an eighth lens arranged in sequence along the light path of the incident light from left to right, the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a meniscus concave 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, and the eighth lens is a biconvex positive lens, the third lens and the fourth lens are glued to form a first glued lens group, the sixth lens and the seventh lens are glued to form a second glued lens group, the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are all glass spherical lenses, and the second lens is a glass aspherical lens; the object side surface of the first lens is a convex surface, and the image side surface is a concave surface; the object side surface of the second lens is a convex surface, and the image side surface is a concave surface; the object side surface of the third lens is a convex surface, and the image side surface is a concave surface; the object side surface of the fourth lens is a convex surface, and the image side surface is a convex surface; the object side surface of the fifth lens is a concave surface, and the image side surface is a convex surface; the object side surface of the sixth lens is a concave surface, and the image side surface is a concave surface; the object side surface of the seventh lens is a convex surface, and the image side surface is a convex surface; the object side surface of the eighth lens is a convex surface, and the image side surface is a convex surface; the axial distance between the lenses satisfies the following relationship, the air gap between the first lens and the second lens is 4.443 mm, the air gap between the second lens and the third lens is 11.117 mm, the air gap between the fourth lens and the diaphragm is 3.469 mm, the air gap between the diaphragm and the fifth lens is 5.476 mm, the air gap between the fifth lens and the sixth lens is 0.100 mm, and the air gap between the seventh lens and the eighth lens is 0.099 mm.

2. A welcome light 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, the fifth lens, the sixth lens, the seventh lens and the eighth lens are f1, f2, f3, f4, f5, f6, f7 and f8 respectively, wherein f1, f2, f3, f4, f5, f6, f7 and f8 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, 8.0 < f5 / f < 9.0, -6.0 < f6 / f < -5.0, 5.0 < f7 / f < 6.0, and 6.0 < f8 / f < 7.

0.

3. A welcome light lens according to claim 1, characterized in that: The first lens satisfies the relationship: N d = 1.80, V d = 46.59; the second lens satisfies the relationship: N d = 1.85, V d = 40.12; the third lens satisfies the relationship: N d = 1.80, V d = 46.59; the fourth lens satisfies the relationship: N d = 1.67, V d = 32.17; the fifth lens satisfies the relationship: N d = 1.60, V d = 38.01; the sixth lens satisfies the relationship: N d = 1.95, V d = 17.94; the seventh lens satisfies the relationship: N d = 1.55, V d = 62.74; the eighth lens satisfies the relationship: N d = 1.79, V d = 47.52; wherein N d is the refractive index and V d is the Abbe number.

4. The welcome light lens according to claim 1, wherein: The total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f ≤ 20.

5. A welcome light lens according to claim 1, characterized in that: The F number of the optical system is ≤1.

8.

6. A welcome light 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 ≥ 1.

0.

7. An imaging method for a welcome light lens suitable for a DMD imaging system, characterized in that: The application discloses a welcome light lens suitable for a DMD imaging system, and the lens is characterized by comprising the welcome light lens.

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