A high-brightness low-cost DMD welcome lamp lens and imaging method

Abstract

The present application relates to a kind of high-brightness low-cost DMD welcome lamp lens, the optical system of lens is by the first lens, the second lens, the third lens, diaphragm, the fourth lens and the fifth lens sequentially arranged from left to right along the light path of light incidence composition;Lens is made of plastic and glass material, the first lens, the second lens, the third lens, the fourth lens are plastic aspheric lens, and the fifth lens is glass spherical lens.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 lens, the total length of lens and the radial dimension of each lens are reduced, to achieve lens group miniaturization.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of lenses, in particular to a high-brightness and low-cost DMD welcome light lens and an imaging method. BACKGROUND

[0002] The optical system of a vehicle-mounted projection loqo light generally comprises an illumination system, a film pattern (or a transparent display screen to realize a dynamic pattern) and imaging projection, and is basically a transplanted application of a conventional consumer projection system. At present, there are many vehicle-mounted projection schemes, such as an MLA scheme based on a semiconductor etching process, a traditional film scheme (plastic or glass), a transparent display screen (which can realize a dynamic pattern), and a scheme based on a DLP and an LCOS (such a scheme has a high cost and needs to consider a vehicle-grade chip and LED, is suitable for high-end vehicles, and will be more popular after the cost and corresponding vehicle-grade are reduced). The earliest Guangzhou Passenger Vehicle uses a welcome light scheme of an outside rearview mirror, which is favored by a large number of customers and greatly improves 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 mature DMD scheme capable of projecting different patterns or even dynamic videos, and the brightness and cost are main shackles of the scheme. SUMMARY

[0003] In view of the deficiencies of the prior art, the technical problem to be solved by the application is to provide a high-brightness and low-cost DMD welcome light lens, which has a large light aperture, low tolerance sensitivity and good high-low temperature stability.

[0004] In order to solve the above technical problems, the technical scheme of the application is as follows: a high-brightness and low-cost DMD welcome light lens, an optical system of the lens comprises, from left to right along a light incident path, a first lens, a second lens, a third lens, a diaphragm, a fourth lens and a fifth lens; without considering the reverse curvature caused by the aspherical coefficient, the first lens is a double-concave negative lens, the object side of the first lens is a concave surface, and the image side of the first lens is a concave surface; the second lens is a meniscus concave negative lens, the object side of the second lens is a convex surface, and the image side of the second lens is a concave surface; the third lens is a double-convex positive lens, the object side of the third lens is a convex surface, and the image side of the third lens is a convex surface; the fourth lens is a meniscus convex positive lens, the object side of the fourth lens is a concave surface, and the image side of the fourth lens is a convex surface; the fifth lens is a double-convex positive lens, the object side of the fifth lens is a convex surface, and the image side of the fifth lens is a convex surface; the lenses are made of plastic and glass materials, the first lens, the second lens, the third lens and the fourth lens are plastic aspherical lenses, and the fifth lens is a glass spherical lens.

[0005] 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 and the fifth lens are f1, f2, f3, f4 and f5 respectively, wherein f1, f2, f3, f4 and f5 satisfy the following ratios: -3.0 < f1 / f < -2.0, -52.0 < f2 / f < -51.0, 6.0 < f3 / f < 7.0, 15.0 < f4 / f < 16.0, and 2.0 < f5 / f < 3.0.

[0006] Preferably, the first lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, and V d ≥ 50.0; the second lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, and V d ≥ 50.0; the third lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, and V d ≤ 50.0; the fourth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, and V d ≥ 50.0; and the fifth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, and V d ≥ 50.0; wherein N d is the refractive index, and V d is the Abbe number.

[0007] Preferably, the on-axis distance between each lens satisfies the following relationships: the air gap between the first lens and the second lens is 2.5-3.0 mm; the air gap between the second lens and the third lens is 2.5-3.0 mm; the air gap between the third lens and the diaphragm is 6.0-6.5 mm; the air gap between the diaphragm and the fourth lens is 3.0-3.5 mm; and the air gap between the fourth lens and the fifth lens is 0.1-0.5 mm.

[0008] Preferably, the total optical length TTL of the optical system and the focal length f of the optical system satisfy the relationship: TTL / f ≤ 11.

[0009] Preferably, the F number of the optical system is ≤ 2.4.

[0010] Preferably, the image height H of the optical system and the focal length f of the optical system satisfy the relationship: H / f ≥ 1.0.

[0011] Preferably, the diaphragm of the optical system is located between the third lens and the fourth lens.

[0012] An imaging method of a high-brightness and low-cost DMD welcome light lens is performed according to the following steps: light rays pass through the first lens, the second lens, the third lens, the diaphragm, the fourth lens and the fifth lens in sequence from left to right and then form an image on an imaging surface.

[0013] Compared with the prior art, the present application has the following beneficial effects:

[0014] 1. The imaging angle of the lens to the object is greater than 90 degrees, and a 1cm wide image can be projected at a distance of 100cm while ensuring that TVDistortion<1%;

[0015] 2. The lens has a large clear aperture, low tolerance sensitivity, and good high-low temperature stability, etc.

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

[0017] 4. The lens adopts a glass-plastic hybrid structure, has low manufacturing cost and light weight, and is beneficial to the manufacturing and installation of the module.

[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 axial color difference, sagittal color difference, and high-order color difference are corrected, so that the imaging system can also have high imaging quality at a large angle.

[0020] 7. The advantages of aspheric lenses in correcting aberrations are fully utilized, so that high-definition imaging is achieved while the lens has a smaller lens outer diameter and shorter total optical length, ensuring the miniaturization of the lens.

[0021] 8. The RI is more than 80%.

[0022] The present application will be further described in detail below in combination with the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 The figure is a schematic diagram of the optical structure of the embodiment of the present application.

[0024] Fig. 2 The figure is a full working waveband sagittal color difference graph of the embodiment of the present application.

[0025] Fig. 3 The figure is a full working waveband field curvature distortion graph of the embodiment of the present application.

[0026] Fig. 4 The figure is a full working waveband MTF graph of the embodiment of the present application.

[0027] In the figure: STO-Stop; L1-First lens; L2-Second lens; L3-Third lens; L4-Fourth lens; L5-Fifth lens; IMA-Imaging surface. DETAILED DESCRIPTION

[0028] In order to make the above features and advantages of the present application more obvious and easy to understand, the following specific examples are described in detail below with reference to the accompanying drawings.

[0029] As shown in Figs. 1-4 A high-brightness and low-cost DMD welcome light lens, the optical system of the lens is composed of a first lens, a second lens, a third lens, a diaphragm, a fourth lens and a fifth lens arranged in order from left to right along the light incident path.

[0030] In the embodiment of the present application, the first lens and the second lens are both plastic aspheric lenses with negative focal length, which can adjust the large-angle light and reduce the distortion of the optical system. Reasonable lens matching makes the optical system achieve wide-angle, low-distortion, low-dispersion, large-aperture, low-temperature drift design, and the on-axis and off-axis aberrations are well corrected, so that the lens has good imaging quality, as shown in Figs. 2 to 4 The technical indicators achieved by the optical system of the embodiment are as follows:

[0031] (1) focal length: 3.0≤EFFL≤4.0mm;

[0032] (2) aperture F≤2.5;

[0033] (3) field of view angle: 2w≥94°;

[0034] (4) working waveband: visible light waveband.

[0035] To achieve the above design parameters, the specific design of the optical system of the embodiment is shown in the following table:

[0036]

[0037]

[0038] The aspheric coefficients of each aspheric lens of the optical system of the embodiment are as follows:

[0039]

[0040] The optical system of the embodiment reasonably allocates the focal length, surface shape, center thickness of each lens and the on-axis distance between each lens, etc., to meet the requirements of lens imaging performance while reducing the total length of the lens and the radial size of each lens, achieving miniaturization of the lens group.

[0041] The above merely describes preferred embodiments of the present application, but is not intended to limit the present application to other forms, and any person skilled in the art can make changes or modifications to the above disclosed technical contents into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments without departing from the technical solution content of the present application and according to the technical essence of the present application still belongs to the protection scope of the technical solution of the present application.

Claims

1. A high-brightness low-cost DMD welcome light lens, comprising an optical system, characterized in that: The optical system of the lens is composed of a first lens, a second lens, a third lens, a diaphragm, a fourth lens and a fifth lens arranged in sequence from left to right along the light path of the incident light; without considering the reverse bending caused by the aspherical coefficient, the first lens is a double-concave negative lens; the second lens is a meniscus concave negative lens; the third lens is a double-convex positive lens; the fourth lens is a meniscus convex positive lens; and the fifth lens is a double-convex positive lens; the first lens, the second lens, the third lens and the fourth lens are plastic aspherical lenses, and the fifth lens is a glass spherical lens; The object side of the first lens is concave, and the image side is concave; the object side of the second lens is convex, and the image side is concave; the object side of the third lens is convex, and the image side is convex; the object side of the fourth lens is concave, and the image side is convex; and the object side of the fifth lens is convex, and the image side is convex; The on-axis distance between each lens satisfies the following relationship: the air gap between the first lens and the second lens is 2.634 mm; the air gap between the second lens and the third lens is 2.649 mm; the air gap between the third lens and the diaphragm is 6.308 mm; the air gap between the diaphragm and the fourth lens is 3.076 mm; and the air gap between the fourth lens and the fifth lens is 0.1 mm.

2. A high-brightness low-cost DMD 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 and the fifth lens are f1, f2, f3, f4 and f5 respectively, wherein f1, f2, f3, f4 and f5 satisfy the following proportions: -3.0 < f1 / f < -2.0, -52.0 < f2 / f < -51.0, 6.0 < f3 / f < 7.0, 15.0 < f4 / f < 16.0, and 2.0 < f5 / f < 3.

0.

3. A high-brightness low-cost DMD welcome light lens according to claim 1, characterized in that: The first lens satisfies the relation: N d = 1.54, V d = 55.71; the second lens satisfies the relation: N d = 1.54, V d = 55.71; the third lens satisfies the relation: N d = 1.66, V d = 20.38; the fourth lens satisfies the relation: N d = 1.54, V d = 55.71; the fifth lens satisfies the relation: N d = 1.57, V d = 71.30; wherein N d is the refractive index and V d is the Abbe number.

4. A high-brightness low-cost DMD welcome light 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 ≤ 11.

5. A high-brightness low-cost DMD welcome light lens according to claim 1, characterized in that: The F number of the optical system is ≤2.

4.

6. A high-brightness low-cost DMD 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. A high-brightness low-cost DMD welcome light lens according to claim 1, characterized in that: The diaphragm of the optical system is located between the third lens and the fourth lens.

8. An imaging method applied to the high-brightness low-cost DMD welcome lamp lens of claim 1, characterized in that, The following steps are performed: the light rays pass through the first lens, the second lens, the third lens, the diaphragm, the fourth lens and the fifth lens in sequence from left to right, and then are imaged on the imaging plane.

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