Projection lens for automobile dynamic floor lighting lamp

Abstract

The invention provides a projection lens for an automobile dynamic floor lighting lamp, which comprises a display chip, a lens and a diaphragm which are sequentially arranged from an object side to an image side, an image generated by the display chip is projected to an image surface through the lens, the diaphragm coincides with an emergent surface of the lens, a reverse light path mode is adopted in design, the image surface is used as an object, and the image surface is used as the image surface. And then the image is reversely imaged to a display chip surface, and the lens is an image space telecentric lens. The beneficial effects of the invention are that: 1, the lens is short in length, compact in size, and convenient for vehicle-mounted flexible installation; 2, the light-emitting aperture is small, and the influence on the appearance surface of a vehicle body is small; the number of the lenses is small, only two aspheric lenses are arranged, and the structure is simple; 4, the design of the full-plastic lens is beneficial to mass production and low in cost; 5, the weather resistance requirement of the vehicle gauge is met, and the imaging effect in high and low temperature environments is excellent; 6, the design can meet different projection distances, and the adaptability is high; 7, a dynamic display chip is matched for projection, and a better visual effect is provided for a user.

Description

Technical Field

[0001] The invention relates to the technical field of optical projection, and in particular to a projection lens for a dynamic ground lamp of an automobile. Background Art

[0002] With the increasing popularity of vehicles and the continuous development of automotive lighting technology, on-board welcome, entertainment, and personalized floor lights are also widely used in various types of cars. Usually, the on-board floor lights are installed under the door or in the reflectors on both sides. When the door is opened, the welcome floor lights will be lit and project certain patterns on the ground, such as the car logo, etc. It can not only serve as a car body decoration, but also illuminate the lower part of the car body or the surrounding area, improving the fashion, personalization, human-vehicle interaction experience and safety of the vehicle.

[0003] At present, some of the vehicle-mounted ground lights adopt the film method, the projection pattern is fixed, the display content is relatively simple, and it cannot provide users with a better experience. For example: in patent CN106292140 (such as background Figure 1 As shown), two Fresnel lenses are used to sandwich the display screen. The outgoing light passes through the rear Fresnel lens and converges to reach the projection assembly, and is projected onto the ground through the projection assembly. Since the Fresnel lens has a certain focal length and rear working distance, the rear optical element is relatively far away from it. In order to shorten the length of the welcome projection lamp, a reflector is added between the rear Fresnel lens and the projection assembly. As a result, the light path from the display screen to the system outlet is too long, the total length of the lens is too long, and the volume is difficult to reduce. In another part of the display solutions with dynamic content projection, DLP projection is used. The system volume is too large, which is not conducive to flexible installation in the car. This is mainly restricted by the reflective principle of the DLP display chip and the design of the projection lamp lens. For example: Patent CN218895328U (as shown in the background Figure 2 As shown in the figure, it adopts the DLP projection solution. After emitting light from the DMD display chip, it includes in sequence: an equivalent prism, a first lens group, a second lens group, a concave reflector and a plane reflector. The first lens group is used to correct spherical aberration and chromatic aberration, the second lens group is used to correct coma and astigmatism, and the concave reflector is used to control TV distortion. The solution includes 7 refractive lenses and a concave reflector, including 2 aspherical lenses and 1 non-curved reflector. The total length of the lens exceeds 100mm, and it is obviously impossible to install it in a position such as a car-mounted rearview mirror. In addition, the aperture is located in the middle of the lens, which causes the light output aperture of the lens to be too large, which will excessively damage the design of the exterior facade of the vehicle and affect the appearance of the entire vehicle.

[0004] Therefore, how to provide a device with dynamic display function, short lens length, compact size, flexible vehicle installation, small light output aperture, little impact on the vehicle body appearance, and better visual effect for users is a technical problem that technical personnel in this field need to solve. Summary of the invention

[0005] In order to solve the technical problems in the prior art that the projection image cannot change dynamically, the projection image has an irregular shape and the projection lens is too large, the present invention provides a projection lens for a dynamic ground lamp of an automobile.

[0006] The present invention provides a projection lens for a dynamic ground lamp of an automobile, comprising a display chip, a lens and an aperture which are arranged in sequence from the object side to the image side. The image generated by the display chip is projected onto the image plane through the lens. The aperture coincides with the exit surface of the lens. The design adopts a reverse light path method, with the image plane as the object, and then reversely imaged onto the display chip surface. The lens is an image-side telecentric lens.

[0007] As a further improvement of the present invention, the lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence from the object side to the image side, the front surface of the first lens is the aperture, and the incident light of different fields of view is quickly deflected by the second lens to form a set image height, the second lens, the third lens, and the fourth lens are used to balance coma, astigmatism and field curvature, the first lens, the third lens, and the fourth lens are used to decompose the optical power, and the fifth lens is used to correct the main light emission angle to form an image-side telecentric optical path.

[0008] As a further improvement of the present invention, the first lens is convex near the image plane, the first lens is concave near the object plane, and the convex surface and the concave surface of the first lens are spherical lenses respectively;

[0009] The second lens has a concave surface close to the image plane and a convex surface close to the object plane, and the concave surface and the convex surface of the second lens are both aspherical lenses;

[0010] The third lens has a convex surface close to the image plane and a concave surface close to the object plane, and the convex surface and the concave surface of the third lens are both aspherical lenses;

[0011] The fourth lens has a concave surface close to the image plane and a convex surface close to the object plane, and the concave surface and the convex surface of the fourth lens are spherical lenses respectively;

[0012] The fifth lens has a convex surface close to the image plane, and a convex surface close to the object plane. The two convex surfaces of the fifth lens are spherical lenses.

[0013] As a further improvement of the present invention, the first lens, the third lens, the fourth lens, and the fifth lens respectively have positive optical power, and the second lens has negative optical power.

[0014] As a further improvement of the present invention, the lens comprises a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence from the object side to the image side.

[0015] The first lens has a convex surface close to the image plane and a concave surface close to the object plane, and the convex surface and the concave surface of the first lens are spherical lenses respectively;

[0016] The second lens has a concave surface close to the image plane and a convex surface close to the object plane, and the concave surface and the convex surface of the second lens are both aspherical lenses;

[0017] The third lens has a convex surface close to the image plane and a concave surface close to the object plane, and the convex surface and the concave surface of the third lens are both aspherical lenses;

[0018] The fourth lens has a concave surface close to the image plane and a convex surface close to the object plane, and the concave surface and the convex surface of the fourth lens are spherical lenses respectively;

[0019] The fifth lens has a convex surface close to the image plane, and a convex surface close to the object plane. The two convex surfaces of the fifth lens are spherical lenses respectively.

[0020] As a further improvement of the present invention, the first lens, the third lens, the fourth lens and the fifth lens respectively have positive optical power, and the second lens has negative optical power.

[0021] As a further improvement of the present invention, the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all plastic lenses.

[0022] As a further improvement of the present invention, the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all plastic lenses.

[0023] As a further improvement of the present invention, the lens is an image-side telecentric lens with a front aperture.

[0024] As a further improvement of the present invention, the display chip is a 1.12-inch TFT chip, the pixel size is 84um, the resolution projection ratio TR=1.11, the offset OFFSET=0%, F / #=2.8, and F# is a parameter indicating the light transmission ability of the lens.

[0025] The beneficial effects of the present invention are: 1. The lens is short in length and compact in size, which is convenient for flexible installation in the vehicle; 2. The light output aperture is small, which has little impact on the appearance of the vehicle body; 3. The number of lenses is small, there are only two aspherical lenses, and the structure is simple; 4. The all-plastic lens design is conducive to mass production and low in cost; 5. It meets the weather resistance requirements of vehicle regulations and has excellent imaging effects in high and low temperature environments; 6. The design can meet different projection distances and has strong adaptability; 7. Matching dynamic display chips for projection gives users better visual effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1-2 It is the background diagram of the present invention;

[0027] Figure 3 It is a structural schematic diagram of the imaging system of the automobile ground projection lamp of the present invention;

[0028] Figure 4 is a schematic diagram of the lens structure of the first embodiment of the present invention;

[0029] Figure 5 This is the MTF diagram of the projection surface when the temperature is 20° C. and the MTF observation line pair is 61p / mm according to the first embodiment of the present invention;

[0030] Figure 6 This is the MTF diagram of the projection surface when the temperature is -40°C and the MTF observation line pair is 61p / mm according to the first embodiment of the present invention;

[0031] Figure 7 This is the MTF diagram of the projection surface when the temperature is 50° C. and the MTF observation line pair is 61p / mm according to the first embodiment of the present invention.

[0032] Figure 8 is a lens distortion diagram of the first embodiment of the present invention;

[0033] Fig. 9 This is a vertical axis chromatic aberration diagram of Embodiment 1 of the present invention;

[0034] Fig.10 This is an image-space telecentricity diagram of a first embodiment of the present invention;

[0035] Fig.11 1 is a schematic diagram of the change of the image spot size when FOV=1 when the projection distance changes from 700 mm to 2500 mm according to the first embodiment of the present invention;

[0036] Fig.12 is a schematic diagram of the lens structure of the second embodiment of the present invention;

[0037] Fig.13 Schematic diagram of the full-field MTF at 20° C. ambient temperature of the second embodiment of the present invention. DETAILED DESCRIPTION

[0038] The purpose of the present invention is to provide a projection lens for a dynamic ground light of an automobile, which uses a small-sized TFT module as a display chip to generate a dynamic color image source, and then projects a large-sized dynamic display screen on the ground through a small-sized, high-quality lens. The small-sized lens and display module can be hidden and installed in the rear-view mirror of the automobile, and the lens has a small light-emitting aperture, which does not affect the appearance of the rear-view mirror of the automobile and does not increase the volume of the existing rear-view mirror.

[0039] like Figure 3 As shown, the present invention discloses a projection lens for a dynamic ground lamp for an automobile, comprising a display chip 10, a lens 11 and an aperture 12 arranged in sequence from the object side to the image side. The image generated by the display chip 10 is projected onto an image plane 13 through the lens 11. The aperture 12 coincides with the exit surface of the lens 11. The design adopts a reverse light path method, with the image plane 13 as the object, and then reversely imaged onto the display chip surface 10.

[0040] The lens 11 adopts an image-side telecentric lens with a front aperture, a small light outlet, and is convenient for hidden installation. The image is clear within a large depth of field, and it can be installed in the rearview mirror housing for ground projection, which can achieve a large format. The image-side telecentric design matches the backlight design of the display chip 10, with high coupling efficiency from lighting to imaging, low stray light, and high contrast.

[0041] The projection lens has the following parameters: the display chip 10 is a 1.12-inch TFT chip, and the pixel size is 84 um. The resolution projection ratio TR=1.11, the offset OFFSET=0%, and F / #=2.8 (F# is a parameter indicating the light transmission capability of the lens).

[0042] In the first embodiment, the structure of the lens is as follows Figure 4 .

[0043] In the first embodiment, the refractive index nd of the first lens 21 satisfies 1.54≤nd1≤1.64, the refractive index nd of the second lens 22 satisfies 1.64≤nd2≤2.0, the refractive index nd of the third lens 23 satisfies 1.54≤nd3≤1.64, the refractive index nd of the fourth lens 24 satisfies 1.54≤nd4≤1.6, and the refractive index nd of the fifth lens 25 satisfies 1.54≤nd5≤1.61.

[0044] The Abbe number Vd of the first lens 21 is 55.6±1%, the Abbe number Vd of the second lens 22 is 23.3±1%, the Abbe number Vd of the third lens 23 is 55.6±1%, the Abbe number Vd of the fourth lens 24 is 55.6±1%, and the Abbe number Vd of the fifth lens 24 is 55.6±1%.

[0045] The curvature radius of the surface S1 of the first lens 21 is 12.5508±0.05mm, and the cone coefficient is 0. The curvature radius of the surface S2 of the first lens 21 is 582.3097±0.05mm, and the cone coefficient is 0. The curvature radius of the surface S3 of the second lens 22 is -3.9828±0.05mm, and the cone coefficient is -2.808172. The curvature radius of the surface S4 of the second lens 22 is -6.5013±0.05mm, and the cone coefficient is -8.156508±0.05. The curvature radius of the surface S5 of the third lens 23 is 7.6370±0.05mm, and the cone coefficient is -4.570 067±0.05, the radius of curvature of the surface S6 of the third lens 23 is 27.1560±0.05mm, and the cone coefficient is 1.914765±0.05, the radius of curvature of the surface S7 of the fourth lens 24 is -13.6755±0.05mm, and the cone coefficient is 0, the radius of curvature of the surface S8 of the fourth lens 24 is -14.1648±0.05mm, and the cone coefficient is 0, the radius of curvature of the surface S9 of the fifth lens 24 is 121.1237±0.05mm, and the cone coefficient is 0, and the radius of curvature of the surface S10 of the fifth lens 24 is -42.2513±0.05mm, and the cone coefficient is 0.

[0046] The actual design parameters refer to Table 1 and Table 2.

[0047] Table 1:

[0048]

[0049] Table 2:

[0050] Aspheric coefficient S3 S4 S5 S6 r4 1.845E-04 1.486E-04 5.539E-05 2.477E-05 r6 1.304E-06 1.756E-06 -3.953E-07 1.381E-07 r8 8.077E-09 1.213E-08 -2.462E-09 -2.900E-09 r10 -2.775E-10 1.290E-11 3.184E-11 -2.308E-11 r12 5.534E-12 3.781E-12 -3.494E-13 -1.489E-13 r14 -3.545E-14 1.770E-15 -4.449E-15 5.132E-16 r16 -9.617E-15 -2.553E-15 4.085E-17 1.069E-17

[0051] The equation of the aspheric curve in optical parameters is as follows:

[0052]

[0053] In the formula, c is the curvature corresponding to the radius, r is the radial coordinate, and its unit is the same as the lens length unit, k is the cone coefficient, and r2~r16 represent the coefficients corresponding to each radial coordinate respectively.

[0054] In the first embodiment:

[0055] The lens parameters are as follows: total length TTL = 39.9 ± 0.1 mm, focal lengths of each lens are: f1 = 24.3 ± 0.1 mm, f2 = -15.1 ± 0.1 mm, f3 = 18.2 ± 0.1 mm, f4 = 310 ± 0.1 mm, f5 = 53.2 ± 0.1 mm. Maximum field of view ± 27°, effective focal length of the lens 28.1 mm.

[0056] The front surface of the first lens 21 is the aperture of the lens. The incident light of different fields of view is quickly deflected by the second lens 22 to form a specific image height. The second lens 22, the third lens 23, and the fourth lens 24 are used to balance coma, astigmatism and field curvature. The first lens 21, the third lens 23 and the fourth lens 24 are mainly used to resolve the focal length. The fifth lens 25 corrects the main light emission angle to form an image-side telecentric optical path.

[0057] In the first embodiment, the MTF (modulation transfer function) diagram of the image side (display chip 10 end) is as follows: Figures 5 to 7 The MTF (Modulation Transfer Function) graph represents the comprehensive analytical capability of the optical system. In the graph, the horizontal axis represents the spatial frequency, and the unit is cycles per millimeter (cycles / mm); the vertical axis represents the value of the MTF (Modulation Transfer Function). The value of the MTF (Modulation Transfer Function) is used to evaluate the imaging quality of the lens, and the value range is 0 to 1. The higher and straighter the MTF curve is, the better the imaging quality of the lens is, the stronger the ability to restore the real image is, the better the degree of overlap of the curves of each field of view is, and the better the consistency of the image quality is.

[0058] from Figures 5 to 7 It can be seen that in the design band, when the spatial frequency is 61p / mm, the MTF of the full field of view is ≥0.3, and only in the extreme environment of low temperature -40°C, the MTF of the edge sagittal field of view is lower than 0.5, and under other conditions, the MTF is greater than 0.5, indicating that the projection lens 11 of the present invention has good image quality and no obvious temperature drift. It should be noted that most dynamic ground projection lamps work at night, and the ambient temperature is generally less than 50°C.

[0059] Figure 8 Schematic diagram of the distortion of the lens 11 of the first embodiment. In the figure, the horizontal axis represents the percentage of distortion, and the vertical axis represents the field of view angle. It can be seen from the figure that the distortion of the whole field of view is less than 0.5%.

[0060] Fig. 9 : This is a vertical axis chromatic aberration diagram of the lens 11 of Example 1. In the diagram, the three curves of red, green and blue represent three wavelengths, with green being the main wavelength. The ordinate represents the field of view angle, and the abscissa represents the height difference between the main ray at the image plane under the red and blue wavelengths and the main wavelength, which is the vertical axis chromatic aberration. It can be seen from the diagram that the maximum vertical axis chromatic aberration of the entire field of view is less than 14um.

[0061] Fig.10 The angles (relative to the normal) of the principal ray incident on the image plane 10 at different image heights in the first embodiment. This measures the telecentricity of the lens 11 on the image side. As can be seen from the figure, the image side telecentricity of the lens 11 in the first embodiment is less than 1°.

[0062] Fig.11The image spot size of the maximum field of view changes when the projection distance (the distance from the image plane 13 to the projection lens 11) changes from 700 mm to 2500 mm in Example 1. It can be seen from the figure that the RMS radius of the spot in the whole range is less than 70 um.

[0063] In the second embodiment, the structure of the lens is as follows Fig.12 .

[0064] In the second embodiment, the refractive index nd of the first lens 31 satisfies 1.54≤nd1≤1.64, the refractive index nd of the second lens 32 satisfies 1.64≤nd2≤2.0, the refractive index nd of the third lens 34 satisfies 1.54≤nd3≤1.64, the refractive index nd of the fourth lens 34 satisfies 1.54≤nd4≤1.6, and the refractive index nd of the fifth lens 35 satisfies 1.54≤nd5≤1.61.

[0065] The Abbe number Vd of the first lens 31 is 55.6±1%, the Abbe number Vd of the second lens 32 is 23.3±1%, the Abbe number Vd of the third lens 33 is 55.6±1%, the Abbe number Vd of the fourth lens 34 is 30±1%, and the Abbe number Vd of the fifth lens 35 is 27±1%.

[0066] The curvature radius of the surface S1 of the first lens 31 is 12.2418±0.05mm, and the cone coefficient is 0. The curvature radius of the surface S2 of the first lens 31 is -989.856±0.05mm, and the cone coefficient is 0. The curvature radius of the surface S3 of the second lens 32 is -5.1411±0.05mm, and the cone coefficient is -2.358172±0.05. The curvature radius of the surface S4 of the second lens 32 is -7.0214±0.05mm, and the cone coefficient is -4.856508±0.05. The curvature radius of the surface S5 of the third lens 33 is 6.25±0.05mm, and the cone coefficient is -5.17 0067±0.05, the radius of curvature of the surface S6 of the third lens 33 is -255.7214±0.05mm, and the cone coefficient is 2.414765±0.05, the radius of curvature of the surface S7 of the fourth lens 34 is -12.2381±0.05mm, and the cone coefficient is 0, the radius of curvature of the surface S8 of the fourth lens 34 is -18.5769±0.05mm, and the cone coefficient is 0, the radius of curvature of the surface S9 of the fifth lens 35 is 103.7385±0.05mm, and the cone coefficient is 0, and the radius of curvature of the surface S9 of the fifth lens 35 is -45.2339±0.05mm, and the cone coefficient is 0.

[0067] The actual design parameters refer to Table 3 and Table 4.

[0068] Table 3:

[0069]

[0070] Table 4:

[0071] Aspheric coefficient S3 S4 S5 S6 r4 6.477E-05 1.074E-04 1.683E-05 6.556E-05 r6 2.177E-06 4.526E-06 2.257E-08 -5.581E-07 r8 4.799E-09 9.033E-09 -1.485E-09 -2.882E-09 r10 -5.747E-10 -1.505E-10 -5.387E-12 8.789E-12

[0072] In the second embodiment:

[0073] The lens parameters are as follows: total length TTL = 40 ± 0.1mm, focal lengths of each lens are: f1 = 24.7 ± 0.1mm, f2 = -11.5 ± 0.1mm, f3 = 13.8 ± 0.1mm, f4 = -547 ± 1mm, f5 = 52.6 ± 0.1mm. Maximum field of view ± 27°, effective focal length of the lens 28.1mm.

[0074] Fig.13 This is the MTF diagram of the projection surface when the temperature is 20°C and the MTF observation line pair is 61p / mm in Example 2. It can be seen from the figure that in the design band, when the spatial frequency is 61p / mm, the MTF of the full field of view is ≥0.5.

[0075] The beneficial effects of the present invention are:

[0076] 1. The lens is short and compact, making it easy to install in the vehicle;

[0077] 2. Small light aperture, little impact on the appearance of the vehicle body;

[0078] 3. There are only two aspherical lenses with a small number of lenses and a simple structure;

[0079] 4. All-plastic lens design is conducive to mass production and low cost;

[0080] 5. Meet the weather resistance requirements of automotive regulations, and have excellent imaging effects in high and low temperature environments;

[0081] 6. The design can meet different projection distances and has strong adaptability;

[0082] 7. Match dynamic display chip for projection to give users better visual effects.

[0083] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A projection lens for a dynamic ground lamp for an automobile, characterized in that: The invention comprises a display chip (10), a lens (11) and an aperture (12) which are arranged in sequence from the object side to the image side. The image generated by the display chip (10) is projected onto an image plane (13) through the lens (11). The aperture (12) coincides with the exit surface of the lens (11). The design adopts a reverse light path method, with the image plane (13) as the object, and then reversely imaged onto the display chip surface (10). The lens (11) is an image-side telecentric lens.

2. The projection lens for a dynamic ground lamp for an automobile according to claim 1, characterized in that: The lens (11) comprises a first lens (21), a second lens (22), a third lens (23), a fourth lens (24), and a fifth lens (25) which are arranged in sequence from the object side to the image side. The front surface of the first lens (21) is the aperture (12). Incident light of different fields of view is rapidly deflected by the second lens (21) to form a set image height. The second lens (22), the third lens (23), and the fourth lens (24) are used to balance coma, astigmatism, and field curvature. The first lens (21), the third lens (23), and the fourth lens (24) are used to resolve optical power. The fifth lens (25) is used to correct the main light ray exit angle to form an image-side telecentric optical path.

3. The projection lens for a dynamic ground lamp for an automobile according to claim 2, characterized in that: The first lens (21) has a convex surface close to the image plane (13), and a concave surface close to the object plane. The convex surface and the concave surface of the first lens (21) are spherical lenses respectively; The second lens (22) has a concave surface close to the image plane (13), and has a convex surface close to the object plane; the concave surface and the convex surface of the second lens (22) are both aspherical lenses; The third lens (23) has a convex surface close to the image plane (13), and a concave surface close to the object plane; the convex surface and the concave surface of the third lens (23) are both aspherical lenses; The fourth lens (24) has a concave surface close to the image plane (13), and a convex surface close to the object plane; the concave surface and the convex surface of the fourth lens (24) are spherical lenses respectively; The fifth lens (25) has a convex surface close to the image plane (13), and a convex surface close to the object plane. The two convex surfaces of the fifth lens (25) are spherical lenses.

4. The projection lens for a dynamic ground lamp for an automobile according to claim 2, characterized in that: The first lens (21), the third lens (23), the fourth lens (24), and the fifth lens (25) respectively have positive optical power, and the second lens (22) has negative optical power.

5. The projection lens for a dynamic ground lamp for an automobile according to claim 1, characterized in that: The lens (11) comprises a first lens (31), a second lens (32), a third lens (33), a fourth lens (34), and a fifth lens (35) which are arranged in sequence from the object side to the image side. The first lens (31) has a convex surface close to the image plane (13), and has a concave surface close to the object plane; the convex surface and the concave surface of the first lens (31) are spherical lenses respectively; The second lens (32) has a concave surface close to the image plane (13), and has a convex surface close to the object plane; the concave surface and the convex surface of the second lens (32) are both aspherical lenses; The third lens (33) is convex near the image plane (13), and is concave near the object plane; the convex surface and the concave surface of the third lens (33) are both aspherical lenses; The fourth lens (34) is concave near the image plane (13), and is convex near the object plane; the concave surface and the convex surface of the fourth lens (34) are spherical lenses respectively; The fifth lens (35) has a convex surface close to the image plane (13), and the fifth lens (35) has a convex surface close to the object plane. The two convex surfaces of the fifth lens (35) are spherical lenses.

6. The projection lens for a dynamic ground lamp for an automobile according to claim 5, characterized in that: The first lens (31), the third lens (33), the fourth lens (34), and the fifth lens (35) respectively have positive optical power, and the second lens (32) has negative optical power.

7. The projection lens for a dynamic ground lamp for an automobile according to claim 2, characterized in that: The first lens (21), the second lens (22), the third lens (23), the fourth lens (24), and the fifth lens (25) are all plastic lenses.

8. The projection lens for a dynamic ground lamp for an automobile according to claim 5, characterized in that: The first lens (31), the second lens (32), the third lens (33), the fourth lens (34), and the fifth lens (35) are all plastic lenses.

9. The projection lens for a dynamic ground lamp for an automobile according to claim 1, characterized in that: The lens (11) is an image-side telecentric lens with a diaphragm in front.

10. The projection lens for a dynamic ground lamp for an automobile according to claim 1, characterized in that: The display chip (1) is a 1.12-inch TFT chip, with a pixel size of 84 um, a resolution projection ratio TR=1.11, an offset OFFSET=0%, and F / #=2.8, where F# is a parameter indicating the light transmission capacity of a lens.

Images