CN117930477A - Projection lens for vehicle - Google Patents

Abstract

A projection lens for a vehicle comprises a concave reflecting mirror, a front group of mirrors and a rear group of mirrors which are sequentially arranged from the image side to the object side of the projection lens for the vehicle. The front group lens group comprises a first lens and a second lens which are sequentially arranged from an image side to an object side. The rear group lens assembly comprises a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an image side to an object side. The distance between the concave reflector and the first lens on the optical axis divided by the total length of the lens is 0.02-0.45, and the maximum half field angle of the projection lens for the vehicle is 80-85 degrees.

Description

Projection lens for vehicle

Technical Field

The invention relates to a projection lens for a vehicle.

Background

Generally, to project a large-sized image at a short projection distance, a special wide-angle lens including a mirror is often used to reduce the projection distance. However, in the present design, in order to effectively reduce the distortion and chromatic aberration of the lens, a larger number of lens sheets is often required to correct the error. However, the added lens has the problems of overlarge volume and overhigh cost, so that how to combine the volume, the cost and the optical effect of the lens is one of the directions of the rest of the field.

Disclosure of Invention

Other objects and advantages of the present invention will be further understood from the technical features disclosed in the embodiments of the present invention.

An embodiment of the invention provides a projection lens for a vehicle, which comprises a concave reflecting mirror, a front group of mirrors and a rear group of mirrors which are sequentially arranged from an image side to an object side of the projection lens for the vehicle, wherein the front group of mirrors and the rear group of mirrors are separated by an aperture of the projection lens for the vehicle, and the total number of lenses of the front group of mirrors and the rear group of mirrors is smaller than 10. The front group lens group comprises a first lens and a second lens which are sequentially arranged from an image side to an object side, and at least one of the first lens and the second lens is an aspheric lens with negative diopter at the center of the lens. The rear group lens group comprises a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an image side to an object side, and the third lens, the fourth lens, the fifth lens and the sixth lens are all glass lenses. The distance between the concave mirror and the first lens on the optical axis divided by the total length of the lens is 0.02-0.45, and the maximum half field angle (maximum semi-FOV) of the projection lens for the vehicle is 80-85 degrees. By the design of the embodiment, a larger projection angle and a more compact projection optical system can be provided.

Another embodiment of the present invention provides a projection lens for a vehicle, including a concave mirror, a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in a direction. At least one of the first lens and the second lens is an aspheric lens with negative diopter. The third lens and the fourth lens are combined lenses, and the fifth lens and the sixth lens are glass lenses. The total number of lenses of the projection lens for the vehicle is less than 10, the distance between the concave reflecting mirror and the first lens on the optical axis is divided by the total length of the lenses, the value is between 0.02 and 0.45, and the maximum half field angle of the projection lens for the vehicle is between 80 and 85 degrees. By the design of the embodiment, a larger projection angle and a shorter projection optical system size can be provided.

By the design of the embodiments of the invention, the projection lens for the vehicle, which has at least one of the advantages of light weight, low cost, wide viewing angle, larger projection angle and shorter system size, can be provided.

In order to make the above features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a schematic view of a projection apparatus for a vehicle according to an embodiment of the invention.

Fig. 2 is an optical structure diagram of a vehicular projection lens according to an embodiment of the invention.

Fig. 3 is an optical structure diagram of a projection lens for a vehicle according to another embodiment of the invention.

Fig. 4 is an optical structure diagram of a projection lens for a vehicle according to another embodiment of the invention.

Fig. 5 is an optical structure diagram of a projection lens for a vehicle according to another embodiment of the invention.

Fig. 6 is an optical structure diagram of a projection lens for a vehicle according to another embodiment of the invention.

Detailed Description

The terms "first" and "second" used in the following embodiments are used to identify the same or similar technical content, features and effects of the present invention, and will be clearly presented in the following detailed description of the embodiments with reference to the drawings. The directional terms mentioned in the following embodiments are, for example: upper, lower, left, right, front or rear, etc., are merely references to the directions of the attached drawings. Thus, the directional terminology is used for purposes of illustration and is not intended to be limiting of the invention. In order to show the features of the present embodiment, only the structure related to the present embodiment is shown, and the remaining structures are omitted.

The lens according to the present invention is a lens comprising a part or all of a transparent material and having a refractive power (power), and is typically composed of glass or plastic. May include general lenses (lens), prisms (prism), diaphragms, cylindrical lenses, biconic lenses, cylindrical array lenses, wedge plates (wedge), or combinations of the foregoing elements.

When the lens is used in a projection system, the image side refers to the side of the optical path that is closer to the imaging surface (e.g., the screen), and the object side refers to the side of the optical path that is closer to the light source or the light valve.

The object-side (or image-side) of a lens has a convex (or concave) portion in an area, meaning that the area is more "convex" outwardly (or "concave") in a direction parallel to the optical axis 12 than an area radially immediately outside the area.

Fig. 1 is a schematic view of a projection apparatus for a vehicle according to an embodiment of the invention. Referring to fig. 1, in the present embodiment, a vehicular projection apparatus 10 includes a light source 20, a light valve 30, and a vehicular projection lens 100. The light source 20 is used for providing light with different wavelengths as a source of image light, and the light valve 30 can be used for converting illumination light with different wavelengths into image light. The light valve 30 may be a reflective light Modulator such as a liquid crystal silicon (LCoS) panel (Liquid Crystal On Silicon panel) or a Digital Micromirror Device (DMD), or the light valve 30 may be a transmissive light Modulator such as a transmissive liquid crystal panel (TRANSPARENT LIQUID CRYSTAL PANEL), an Electro-optical Modulator (Electro-Optical Modulator), a Magneto-optical Modulator (Magneto-optical Modulator), or an acousto-optical Modulator (Acousto-optical Modulator, AOM). In various embodiments of the present invention, the type and kind of the light source 20 and the light valve 30 are not limited. The vehicular projection lens 100 is used for projecting and imaging image light on a projection surface of an object. The projection lens 100 for a vehicle includes a combination of lenses with diopters, and in some embodiments, in addition to the lenses and the aperture, elements such as a plane mirror or a curved mirror may be optionally added between the lenses in the projection lens 100 for a vehicle to reflect and turn the light path of the light beam, and project the image light from the light valve 30 to the projection target. In this embodiment, the vehicle projection apparatus 10 further includes a prism 40, a glass cover 50, and the like. The glass cover 50 is used for dust prevention to protect the light valve 30, the prism 40 is used for adjusting the light paths of different wavelengths, in this example, the light valve 30 is arranged at the downstream of the light path of the light source 20, the vehicle projection lens 100 is arranged at the downstream of the light path of the light valve 30, the light valve 30 converts the light beam into an image light beam with image information, the image light beam can sequentially pass through the glass cover 50 and the prism 40 to the vehicle projection lens 100, and finally the image light beam is projected and imaged on a projection surface outside the vehicle projection device 10 by the vehicle projection lens 100.

Fig. 2 is an optical structure diagram of a vehicular projection lens according to a first embodiment of the present invention. Referring to fig. 2, in the present embodiment, the concave mirror 110, the front group of mirrors 120, the aperture (minimum clear aperture) 140, and the rear group of mirrors 130 are sequentially arranged along the optical axis 12 of the vehicular projection lens 100a from the image side IS to the object side OS, wherein the object side OS IS the light input side of the vehicular projection lens 100a corresponding to the light valve 30, and the image side IS the light output side of the vehicular projection lens 100a corresponding to the screen. Further, the prism 40, the glass cover 50 and the light valve 30 are arranged in this order from the image side IS to the object side OS. In the present embodiment, the concave mirror 110 has an aspheric surface, and the concave mirror 110 is axisymmetric with respect to the optical axis 12 of the projection lens 100a for the vehicle, but the invention is not limited thereto. In another embodiment, as shown in fig. 6, at least one plane mirror (illustrated as two plane mirrors 150, 152 to bend the optical path, so that the optical center of the concave mirror 110 IS not on the line connecting the optical centers of the lens closest to the image side IS and the lens closest to the object side OS) may be additionally disposed in the optical path between the concave mirror 110 and the lens.

Referring to fig. 2 again, in the present embodiment, the front group lens assembly 120 includes a lens L1 and a lens L2 sequentially arranged from the image side IS to the object side OS, the rear group lens assembly 130 includes a lens L3, a lens L4, a lens L5 and a lens L6 sequentially arranged from the image side IS to the object side OS, and the front group lens assembly 120 and the rear group lens assembly 130 are separated by an aperture stop 140 of the vehicle projection lens 100 a. In the present embodiment, an aperture (minimum clear aperture) 140 is provided between the lens L2 and the lens L3. In the present embodiment, the diopters of the front group 120 are negative, the diopters of the rear group 130 are positive, and the diopters of the lenses L1-L6 are negative, positive, and positive, respectively. In the present embodiment, the lens L3 and the lens L4 can form a combined lens, that is, the adjacent two sides of the lens L3 and the lens L4 have substantially the same (the difference of curvature radius is less than 0.005 mm) or completely the same (substantially the same) curvature radius, the lenses L1, L2 and L6 are aspheric lenses, the lenses L1 and L2 can be plastic lenses, the material of the plastic lenses can be PMMA or PC, but not limited thereto, the lenses L3-L5 can be spherical glass lenses, and the lens L6 can be molded glass lenses. Furthermore, the number of lenses, the shape of the lenses and the optical characteristics of the projection lens 100a for the vehicle can be designed according to the actual requirements. The image side IS of each embodiment of the present invention IS disposed on the right side of each drawing, and the object side OS IS disposed on the left side of each drawing, which will not be repeated. In the present embodiment, the projection lens 100a for the vehicle may be a fixed focus lens.

The Aperture 140 is an Aperture Stop (Aperture Stop), and the Aperture 140 is a separate component, but the invention is not limited thereto, and the Aperture 140 may be integrated with other optical components. In the present embodiment, the aperture 140 achieves a similar effect by blocking the peripheral light and retaining the light transmission in the middle portion by means of a mechanism member, and the aforementioned mechanism member may be adjustable. By adjustable, it is meant that the position, shape or transparency of the machine element is adjusted. Alternatively, the aperture 140 may also be coated with an opaque light absorbing material on the surface of the lens, and the central portion thereof is kept transparent to limit the light path. The vehicle projection lens may correspond to a smaller aperture value (F-number) as the aperture of the diaphragm 140 is larger.

Spherical lens means that the surfaces of the front and rear of the lens are each part of a spherical surface, and the curvature of the spherical surface is fixed. The lens design parameters and the shape of the projection lens 100a for the vehicle are shown in table one. However, the following description is not intended to limit the invention, and one of ordinary skill in the art, after referencing the present disclosure, would be able to make appropriate changes to the parameters or settings thereof, while still remaining within the scope of the present invention.

Table one describes the values of the optical parameters of the lenses in the optical system, the numbers in the surface numbers represent that the surface is an aspherical surface; otherwise, if no number exists in the surface numbers, the surface numbers are spherical. The radius of curvature, pitch/thickness units in table one are millimeters (mm). Furthermore, it should be noted that the embodiments of the present disclosure take the concave mirror 110 as the origin and the direction toward the object side OS is the negative direction defining distance value, so that, for example, the pitch value and the total lens length value appearing later in the table are negative values.

List one

In table one, the radius of curvature (mm) refers to the radius of curvature of the corresponding surface, and the pitch (mm) refers to the linear distance between two adjacent surfaces on the optical axis 12. For example, the distance between the surfaces S1 and S2, i.e. the distance between the surfaces S1 and S2, is shown as the thickness, refractive index and abbe number of each lens and each optical element in the column. The surfaces S2 and S3 are both surfaces of the lens L1. The surfaces S4 and S5 are both surfaces of the lens L2. For values of parameters such as radius of curvature and spacing of the surfaces, please refer to table one, and will not be repeated here.

The radius of curvature refers to the inverse of the curvature. The radius of curvature is positive, and the center of sphere of the lens surface is in the magnification side (image side) direction of the lens. When the radius of curvature is negative, the center of sphere of the lens surface is in the direction of the reduction side (object side) of the lens, and the convex-concave of each lens is visible in the table above.

The aperture value of the present embodiment is represented by F/# (F-number), and the aperture value (F-number) of the projection lens for vehicles can be 2.2-2.7, preferably 2.3-2.6, and more preferably 2.4-2.5 according to the design of the embodiment of the present invention. In the present embodiment, the aperture value (F-number) of the vehicular projection lens 100a is 2.44. Furthermore, according to the design of the embodiment of the present invention, the projection ratio (projection object distance/projection screen width) of the projection lens for the vehicle may be between 0.13 and 0.2, preferably between 0.14 and 0.19, and more preferably between 0.15 and 0.18. In various embodiments of the present invention, the distance between the concave mirror 110 and the lens closest to the concave mirror 110 (lens L1) on the optical axis 12 divided by the total lens length TL may be between 0.02 and 0.45. Meeting this ratio range provides a larger projection angle and a more compact projection optical system, and provides a good viewing angle range. The total lens length TL may be indicated in fig. 2 as the distance from the outer surface of the concave mirror 110 to the position on the optical axis 12 and the outermost surface (surface S13) of the rear group mirror 130 to the position on the optical axis 12. In the present embodiment, the total lens length tl=82.1 mm, and the distance between the concave mirror 110 and the aspherical lens L1 on the optical axis 12 divided by the total lens length is 0.375. Furthermore, in the present embodiment, the distance between the aspherical lens L1 and the aspherical lens L2 on the optical axis 12 divided by the total lens length TL is 0.1-0.38, preferably 0.12-0.35, and more preferably 0.14-0.32. Meeting this ratio range can effectively shorten the size of the projection optical system and can provide a good viewing angle range. In the present embodiment, the value of the distance between the aspherical lens L1 and the aspherical lens L2 on the optical axis 12 divided by the total lens length TL is 0.268.

In various embodiments of the present invention, the maximum half field angle (maximum semi-FOV) of the projection lens for vehicles is between 80-85 degrees. In the present embodiment, the maximum half field angle of the vehicular projection lens 100a is 80 degrees, and the effective focal length of the vehicular projection lens 100a is 1.09mm.

Spherical lens means that the surfaces of the front and rear of the lens are each part of a spherical surface, and the curvature of the spherical surface is fixed. The aspheric lens refers to at least one of the front and rear surfaces of the lens, wherein the radius of curvature of at least one surface varies along with the central axis, and can be used for correcting aberration. In the following embodiments of the present invention, the aspherical polynomial may be expressed by the following formula:

In the above formula, Z is the offset (sag) in the direction of the optical axis 12, c is the inverse of the radius of the sphere of revolution (osculating sphere), that is, the inverse of the radius of curvature near the optical axis 12, k is the conic coefficient (conic), and r is the aspherical height, that is, the height from the center of the lens to the edge of the lens. A-F of Table II represent the 4 th order, 6 th order, 8 th order, 10 th order, 12 th order, and 14 th order coefficient values of the aspherical polynomial, respectively. However, the following description is not intended to limit the invention, and one of ordinary skill in the art, after referencing the present disclosure, would be able to make appropriate changes to the parameters or settings thereof, while still remaining within the scope of the present invention.

Watch II

K

A

B

C

D

E

F

S1*

-0.981

3.796E-05

-1.733E-07

6.485E-10

-1.706E-12

2.493E-15

-1.464E-18

S2*

-6.322

1.294E-04

-4.048E-06

4.256E-08

-2.382E-10

5.578E-13

S3*

-0.853

-3.833E-05

4.880E-07

3.788E-09

-1.167E-11

S4*

-0.981

-5.090E-04

-5.056E-07

7.239E-09

-1.503E-11

S5*

-0.978

-1.057E-04

-2.061E-06

6.525E-09

-2.063E-11

S12*

1.044

-8.961E-05

-3.270E-06

6.238E-08

-7.188E-10

6.430E-12

S13*

-1.376

-2.873E-04

-2.133E-06

-1.721E-08

1.204E-09

-6.223E-12

In the embodiments of the present invention, the total number of lenses with diopters is less than 10, but the number of lenses, the shape of the lenses and the optical characteristics can be designed differently according to practical requirements without limitation. For example, in one embodiment, two adjacent lens surfaces with substantially the same radius of curvature may be stacked together by a machine component to replace a lens with a larger thickness, and the two lens surfaces may have a high Abbe number (Abbe number) and a low Abbe number, respectively, to provide an effect of correcting chromatic aberration, so that the resolution of the lens is better.

Fig. 3 is an optical structure diagram of a vehicular projection lens 100b according to a second embodiment of the present invention. In the present embodiment, the front group lens assembly 120 includes a lens L1, a lens L2, and a lens L3 sequentially arranged from the image side IS to the object side OS, and the rear group lens assembly 130 includes a lens L4, a lens L5, a lens L6, and a lens L7. In the present embodiment, the diaphragm 140 is disposed between the lens L3 and the lens L4. In the present embodiment, the diopter of the front group lens group 120 is negative, the diopter of the rear group lens group 130 is positive, and the diopters of the lenses L1-L7 are negative, positive, negative, positive, respectively. The lens L4 and the lens L5 may form a combined lens, the lenses L1, L2, L7 are aspheric lenses, the lenses L1, L2 may be plastic lenses, the lenses L3-L6 may be spherical glass lenses, and the lens L7 may be molded glass lenses. In the present embodiment, the total lens length TL is 82.1mm, the distance between the concave mirror 110 and the aspherical lens (lens L1) closest to the concave mirror 110 on the optical axis 12 divided by the total lens length TL is 0.401, the distance between the aspherical lens L1 and the aspherical lens L2 on the optical axis 12 divided by the total lens length TL is 0.222, the effective focal length EFL is 0.95mm, the aperture value (F-number) is 2.46, and the maximum half field angle is 81.6 degrees. The design parameters of the lens and its peripheral elements of the projection lens 100b for the vehicle are shown in table three, and the conic coefficients and aspheric coefficients of the respective aspheric surfaces are shown in table four.

Watch III

Table four

K

A

B

C

D

E

F

S1*

-1.039

3.293E-05

-1.755E-07

6.801E-10

-1.759E-12

2.388E-15

-1.355E-18

S2*

-8.054

8.948E-05

-3.408E-06

4.502E-08

-2.788E-10

8.425E-13

S3*

3.755

-2.044E-04

2.574E-06

7.959E-09

-7.164E-11

S4*

-1.384

-5.498E-04

3.596E-07

1.430E-08

-1.062E-10

S5*

-1.157

-2.449E-04

-1.459E-06

8.708E-09

-3.678E-11

S14*

-2.908

-1.702E-04

-2.565E-06

3.747E-08

-1.690E-10

4.651E-12

S15*

13.849

2.552E-04

-9.824E-06

6.260E-08

1.493E-09

-1.105E-11

Fig. 4 is an optical structure diagram of a vehicular projection lens 100c according to a third embodiment of the present invention. In the present embodiment, the front group lens assembly 120 includes a lens L1, a lens L2, a lens L3, and a lens L4 sequentially arranged from the image side IS to the object side OS, and the rear group lens assembly 130 includes a lens L5, a lens L6, a lens L7, and a lens L8. In the present embodiment, the diaphragm 140 is disposed between the lens L4 and the lens L5. In the present embodiment, the refractive power of the front group 120 is positive, the refractive power of the rear group 130 is positive, and the refractive powers of the lenses L1-L8 are negative, positive, negative, positive, and positive, respectively. The lens L5 and the lens L6 can form a combined lens, the lenses L1 and L2 are aspheric lenses, the lenses L1 and L2 can be plastic lenses, and the lenses L3-L8 can be spherical glass lenses. In the present embodiment, the total lens length TL is 97.63mm, the distance between the concave mirror 110 and the lens closest to the concave mirror 110 (lens L1) on the optical axis 12 divided by the total lens length TL is 0.2766, the distance between the aspherical lens L1 and the aspherical lens L2 on the optical axis 12 divided by the total lens length TL is 0.3138, the effective focal length EFL is 1.06mm, the aperture value (F-number) is 2.44, and the maximum half angle is 81.5 degrees. The design parameters of the lens and its peripheral elements of the projection lens 100c for the vehicle are shown in table five, and the conic coefficients and aspheric coefficients of the respective aspheric surfaces are shown in table six.

TABLE five

TABLE six

K

A

B

C

D

E

S1*

-0.938

7.961E-05

-1.981E-07

3.758E-10

-4.191E-13

2.007E-16

S2*

-3.245

-2.795E-04

1.302E-06

-3.006E-09

5.244E-12

S3*

0.128

-3.265E-04

3.409E-06

-1.156E-08

1.894E-11

S4*

-1.26

-2.566E-04

2.844E-06

-2.283E-08

5.737E-11

S5*

-0.961

-1.072E-04

-3.291E-07

3.763E-09

-2.058E-11

Fig. 5 is an optical structure diagram of a vehicular projection lens 100d according to a fourth embodiment of the present invention. In the present embodiment, the front group lens assembly 120 includes a lens L1, a lens L2, a lens L3, and a lens L4 sequentially arranged from the image side IS to the object side OS, and the rear group lens assembly 130 includes a lens L5, a lens L6, a lens L7, a lens L8, and a lens L9. In the present embodiment, the diaphragm 140 is disposed between the lens L4 and the lens L5. In the present embodiment, the refractive power of the front group 120 is positive, the refractive power of the rear group 130 is positive, and the refractive powers of the lenses L1-L9 are negative, positive, negative, positive, and positive, respectively. The lens L5 and the lens L6 can form a combined lens, the lenses L1 and L2 are aspheric lenses, the lenses L1 and L2 can be plastic lenses, and the lenses L3-L9 can be spherical glass lenses. In the present embodiment, the total lens length TL is 97.73mm, the distance between the concave mirror 110 and the lens closest to the concave mirror 110 (lens L1) on the optical axis 12 divided by the total lens length TL is 0.276, the distance between the aspherical lens L1 and the aspherical lens L2 on the optical axis 12 divided by the total lens length TL is 0.313, the effective focal length EFL is 1.06mm, the aperture value (F-number) is 2.44, and the maximum half field angle is 81.5 degrees. The design parameters of the lens and its peripheral elements of the projection lens 100d for the vehicle are shown in table seven, and the conic coefficients and aspherical coefficients of the respective aspherical surfaces are shown in table eight.

Watch seven

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Table eight

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Embodiments of the present invention provide lower manufacturing costs and overall weight while maintaining adequate imaging quality by employing aspheric plastic lenses and optical lenses consisting of substantially less than 10 lenses. By the design of the embodiments of the invention, the projection lens for the vehicle, which has at least one of the advantages of light weight, low cost, wide viewing angle, larger projection angle and shorter system size, can be provided.

Although the present invention has been described with reference to the above embodiments, it should be understood that the invention is not limited thereto, but rather may be modified or altered somewhat by persons skilled in the art without departing from the spirit and scope of the present invention.

Claims (10)

1. A vehicular projection lens, characterized by comprising:

The front group of lenses and the rear group of lenses are separated by the aperture of the vehicle projection lens, and the total number of lenses of the front group of lenses and the rear group of lenses is smaller than 10;

the front group lens group comprises a first lens and a second lens which are sequentially arranged from the image side to the object side, and at least one of the first lens and the second lens is an aspheric lens with negative lens center diopter;

the rear group lens group comprises a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from the image side to the object side, and the rear group lens group is a glass lens;

the distance between the concave reflector and the first lens on the optical axis divided by the total length of the lens is 0.02-0.45, and the maximum half field angle of the projection lens for the vehicle is 80-85 degrees.

2. A vehicular projection lens, characterized by comprising:

a concave reflector, a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged along a direction;

At least one of the first lens and the second lens is an aspheric lens with negative diopter;

the third lens and the fourth lens are combined lenses;

The fifth lens and the sixth lens are glass lenses;

The total number of lenses of the projection lens for the vehicle is less than 10;

the distance between the concave reflector and the first lens on the optical axis divided by the total length of the lens is 0.02-0.45, and the maximum half field angle of the projection lens for the vehicle is 80-85 degrees.

3. The projection lens for a vehicle according to claim 1 or 2, further comprising two plane mirrors disposed on the path from the concave mirror to the sixth lens.

4. The vehicular projection lens according to claim 1 or 2, wherein a projection ratio of the vehicular projection lens is in a range of 0.13 to 0.2.

5. The vehicular projection lens according to claim 1 or 2, wherein a value of a distance between the first lens and the second lens on an optical axis divided by a total length of the lens is 0.1 to 0.38.

6. The vehicular projection lens according to claim 1 or 2, wherein the sixth lens is an aspherical lens.

7. The projection lens for a vehicle according to claim 1 or 2, further comprising a seventh lens disposed between the second lens and the aperture.

8. The vehicular projection lens according to claim 1 or 2, wherein an aperture value (F-number) of the vehicular projection lens is between 2.2 and 2.7.

9. The vehicular projection lens according to claim 1 or 2, wherein the vehicular projection lens satisfies one of the following conditions: (1) the vehicular projection lens has six lenses arranged in a direction, and lens diopters in the direction are sequentially negative, positive respectively, and (2) the vehicular projection lens has seven lenses arranged in a direction, and lens diopters in the direction are sequentially negative, positive, negative, positive, negative respectively, positive respectively, (3) the projection lens for vehicles has eight lenses arranged in a direction, and the lens diopters in the direction are respectively negative, positive, negative, positive and positive in order, the projection lens for a vehicle of (4) has nine lenses arranged in a direction, and lens diopters in the direction are respectively negative, positive, negative, positive in order.

10. The vehicular projection lens according to claim 1 or 2, wherein the vehicular projection lens satisfies one of the following conditions: (1) the vehicular projection lens has an aspherical lens, a meniscus lens, a biconvex lens, a meniscus lens, and an aspherical lens arranged in one direction, (2) the vehicular projection lens has an aspherical lens, a meniscus lens, a biconvex lens, a meniscus lens, and an aspherical lens arranged in one direction, the vehicular projection lens (3) has an aspherical lens, a biconvex lens, a biconcave lens, a biconvex lens, a meniscus lens, and a meniscus lens arranged in one direction, and the vehicular projection lens (4) has an aspherical lens, a biconvex lens, a biconcave lens, a plano-convex lens, a meniscus lens, and a meniscus lens arranged in one direction.