Vehicle headlight

Abstract

A lens element (3) has: a parabolic surface (32) that is formed at the rear thereof and reflects light emitted from a light source forward; and an emission surface (33) that is formed at the front thereof and emits the light emitted from the light source and reflected by the parabolic surface forward. A light source (2) is provided in the vicinity of the focal point of the parabolic surface. At the rear end of the parabolic surface, a cutoff line formation part (34) having a shape corresponding to a cutoff line is provided in the vicinity of the focal point of the emission surface. At least one of a region behind the cutoff line formation part and a region closer to the light source than the cutoff line formation part in the lens element is configured not to cause light emitted from the light source to contribute to a low beam light distribution pattern.

Description

Vehicle headlights

[0001] The present disclosure relates to a vehicle headlamp.

[0002] Patent Document 1 discloses a vehicle headlamp in which a reflector that reflects light emitted from a light source and a lens that deflects the light reflected by the reflector and irradiates it outside the light source unit are integrally formed with a light-transmitting member that holds the light source. The reflector is formed at the rear end of the light-transmitting member, and the lens is formed at the front end of the light-transmitting member. A cut line forming surface is formed in the middle of the light-transmitting member.

[0003] Japanese Patent Application Publication No. 2004-241349

[0004] The inventors of the present invention have found that a cutoff line forming portion can be created by forming a reflecting surface that reflects light emitted from a light source as a parabolic surface and discontinuing the rear end of the parabolic surface.

[0005] The present disclosure aims to provide a vehicle headlamp including a lens element having a cutoff line forming portion at its rear end.

[0006] A vehicle headlamp according to a first aspect of the present disclosure is a vehicle headlamp that forms a low-beam light distribution pattern forward, including a cutoff line, and comprises: a light source; and a lens element extending in a longitudinal direction, wherein the lens element has: a parabolic surface formed at a rear portion thereof that reflects light emitted from the light source forward; and an exit surface formed at a front portion thereof that emits the light reflected by the parabolic surface forward; the light source is provided near a focus of the parabolic surface; a cutoff line forming portion having a shape corresponding to the cutoff line is provided at the rear end of the parabolic surface; and the cutoff line forming portion is provided near the focus of the exit surface; and at least one of a region of the lens element rearward of the cutoff line forming portion and a region closer to the light source than the cutoff line forming portion is configured so as not to allow the light emitted from the light source to contribute to the low-beam light distribution pattern.

[0007] According to the present disclosure, it is possible to provide a vehicle headlamp including a lens element having a cutoff line forming portion at its rear end.

[0008] 1 is a rear perspective view illustrating the configuration of an optical unit mounted in a vehicle headlamp according to an embodiment of the present disclosure. FIG. 1 is a view of the optical unit of FIG. 1 as seen from behind. FIG. 2 is a cross-sectional view of the optical unit of FIG. 1. FIG. 3 is an example of a low-beam light distribution pattern projected on a virtual vertical screen by light emitted from the optical unit of FIG. 1. FIG. 4 is a rear perspective view illustrating the configuration of an optical unit mounted in a vehicle headlamp according to Modification 1. FIG. 5 is a cross-sectional view of the optical unit of FIG. 6. FIG. 7 is a rear perspective view illustrating the configuration of an optical unit mounted in a vehicle headlamp according to Modification 3. FIG. 8 is a cross-sectional view of the optical unit of FIG. 9. FIG. 9 is an example of a low-beam light distribution pattern projected on a virtual vertical screen by light emitted from the optical unit of FIG. 9. FIG. 10 is a view for explaining the radius of curvature of a cutoff line forming portion. FIG. 11 is a view for explaining the radius of curvature of a cutoff line forming portion.

[0009] Hereinafter, examples of embodiments of the present disclosure will be described with reference to the drawings. In the drawings, arrow U indicates the upward direction of the illustrated structure. Arrow D indicates the downward direction of the illustrated structure. Arrow F indicates the forward direction of the illustrated structure. Arrow B indicates the backward direction of the illustrated structure. Arrow R indicates the rightward direction of the illustrated structure. Arrow L indicates the leftward direction of the illustrated structure. These directions are relative directions set for the optical unit 1 shown in FIG. 1, and the direction of light irradiation of the optical unit 1 is the forward direction.

[0010] 1 is a rear perspective view illustrating the configuration of an optical unit 1 mounted in a vehicle headlamp according to an embodiment of the present disclosure. The optical unit 1 is configured to form a low-beam light distribution pattern including a cut-off line in the forward direction.

[0011] The vehicle headlamp includes an outer lens and a housing (not shown) in addition to the optical unit 1 shown in FIG. 1, and the optical unit 1 is disposed within a lamp chamber formed by the outer lens and the housing.

[0012] 1, the optical unit 1 includes a light source 2 and a lens element 3. The light source 2 is mounted on a substrate (not shown) with its light-emitting surface facing upward. The light source 2 may be, for example, a light-emitting diode (LED) or a laser diode (LD).

[0013] The lens element 3 extends in the front-rear direction and is an optical component made of, for example, a transparent resin material or a glass material. The lens element 3 has an incident surface 31, a parabolic surface 32, and an exit surface 33.

[0014] The parabolic surface 32 is formed at the rear of the lens element 3. In this example, the parabolic surface 32 is a paraboloid of revolution formed by rotating a parabola around an axis extending in the front-to-rear direction. The parabolic surface 32 is configured as a total reflection surface that reflects light emitted from the focus of the parabola forward as parallel light. The light source 2 is disposed near the focus of the parabolic surface 32.

[0015] A cutoff line forming portion 34 having a shape corresponding to the cutoff line of the low beam light distribution pattern is provided at the rear end of the parabolic surface 32. The cutoff line forming portion 34 is provided near the focal point of the exit surface 33.

[0016] Fig. 2 is a rear view of the optical unit 1. In this example, as illustrated in Fig. 2, the cutoff line forming portion 34 extends in the left-right direction and has a step in the center in the left-right direction.

[0017] The exit surface 33 is formed at the front of the lens element 3. The exit surface 33 is formed so as to be convex in the forward direction. The exit surface 33 refracts incident parallel light in any direction and emits the light so as to create a desired light distribution pattern.

[0018] Fig. 3 is a cross-sectional view of the optical unit 1. As illustrated in Fig. 3, a portion of light L1 emitted from the light source 2 and incident on the lens element 3 from the incident surface 31 travels toward the parabolic surface 32. The portion of light L1 that reaches the parabolic surface 32 is reflected forward by the parabolic surface 32. The portion of light L1 that reaches the exit surface 33 is emitted forward.

[0019] 4 illustrates an example of a low-beam light distribution pattern PL projected onto a virtual vertical screen by light emitted from the optical unit 1. The virtual vertical screen is placed, for example, at a position 25 m in front of the optical unit 1. In FIG. 4, H indicates the horizontal line, and V indicates the vertical line passing through the center of the illumination range of the optical unit 1.

[0020] The low-beam light distribution pattern PL has a cutoff line CL corresponding to the cutoff line forming portion 34 of the lens element 3.

[0021] In this way, in the optical unit 1, the cutoff line forming portion 34 is formed as a part of the lens element 3, so that the optical unit 1 can be manufactured with a simple configuration, low cost, and high precision.

[0022] In addition, unlike the present disclosure, there is also known a configuration in which an optical system is configured so that light rays form a focus on the path from the reflecting surface to the exit surface, and a cutoff line forming portion that blocks part of the light is provided near the focus to form an irradiation pattern having a cutoff line. Compared to such a configuration, the length of the lens element 3 in the present disclosure can be easily shortened in the front-to-rear direction.

[0023] 1 , the region below the cutoff line forming portion 34 is configured not to guide light toward the exit surface 33. That is, the region below the cutoff line forming portion 34 of the lens element 3 is configured not to allow the light emitted from the light source 2 to contribute to the low beam distribution pattern PL. The region below the cutoff line forming portion 34 is an example of a region closer to the light source 2 than the cutoff line forming portion 34.

[0024] Specifically, the lens element 3 has a flat surface 35 that is perpendicular to the front-to-rear direction in a region below the cutoff line forming portion 34. The cutoff line forming portion 34 is a ridge line provided at the rear end of the parabolic surface 32. The area above the cutoff line forming portion 34 is the parabolic surface 32, and the area below the cutoff line forming portion 34 is the flat surface 35 that is not a parabolic surface. The flat surface 35 extends flatly downward from the cutoff line forming portion 34 and is a curved surface that extends in the left-to-right direction. The shape of the flat surface 35 when viewed from above is the same as the shape of the cutoff line forming portion 34.

[0025] 3 , a portion of light L2 emitted from light source 2 and incident on lens element 3 from incident surface 31 travels toward flat surface 35. The portion of light L2 that reaches flat surface 35 is refracted at flat surface 35 and passes through lens element 3 toward the rear of lens element 3.

[0026] In the optical unit 1 according to this embodiment, light L2 emitted from the light source 2, incident on the lens element 3, and directed toward a region below the cutoff line forming portion 34 passes through the lens element 3 toward the rear of the lens element 3 without being reflected by the flat surface 35 toward the exit surface 33. Here, the parabolic surface 32 has a shape cut off at its lower end by the cutoff line forming portion 34. Therefore, parallel light reflected from the parabolic surface 32 above the cutoff line forming portion 34 is incident on the exit surface 33, so that a low-beam light distribution pattern PL having an upper portion shielded from light is formed.

[0027] (Modification 1) FIG. 5 is a rear perspective view illustrating the configuration of an optical unit 11 mounted in a vehicle headlamp according to Modification 1. As shown in FIG.

[0028] The optical unit 11 according to the first modification is different from the optical unit 1 according to the above embodiment in the configuration of the area behind the cutoff line forming portion of the lens element.

[0029] 5, the optical unit 11 includes a light source 12 and a lens element 13. The light source 12 is mounted on a substrate (not shown) with its light-emitting surface facing upward. The light source 12 may be, for example, an LED or an LD.

[0030] The lens element 13 extends in the front-rear direction and is an optical component made of, for example, a transparent resin material or a glass material. The lens element 13 has an incident surface 131, a parabolic surface 132, and an exit surface 133.

[0031] The parabolic surface 132 is formed at the rear of the lens element 13. Here, the parabolic surface 132 is a paraboloid of revolution formed by rotating a parabola around an axis extending in the front-to-rear direction. The parabolic surface 132 is configured as a total reflection surface that reflects light emitted from the focus of the parabola forward as parallel light. The light source 12 is disposed near the focus of the parabolic surface 132.

[0032] A cutoff line forming portion 134 having a shape corresponding to the cutoff line of the low beam distribution pattern is provided at the rear end of the parabolic surface 132. The cutoff line forming portion 134 is provided near the focal point of the emission surface 133. In this example, the cutoff line forming portion 134 extends in the left-right direction and has a step in the center in the left-right direction.

[0033] The exit surface 133 is formed at the front of the lens element 13. The exit surface 133 is formed so as to be convex in the forward direction. The exit surface 133 refracts incident parallel light in any direction and emits the light so as to create a desired light distribution pattern.

[0034] Fig. 6 is a cross-sectional view of the optical unit 11. As illustrated in Fig. 6, a portion of light L11 emitted from the light source 12 and incident on the lens element 13 from the incident surface 131 travels toward the parabolic surface 132. The portion of light L11 that reaches the parabolic surface 132 is reflected forward by the parabolic surface 132. The portion of light L11 that reaches the exit surface 133 is emitted forward.

[0035] The lens element 13 has a surface 135 formed continuously from the parabolic surface 132 in a region behind and below the cutoff line forming portion 134. The parabolic surface 132 and the surface 135 together form a single parabolic surface. The cutoff line forming portion 134 is located at the boundary between the parabolic surface 132 and the surface 135.

[0036] Lens element 13 is formed so that the specular reflectance of surface 135 is lower than that of parabolic surface 132. For example, the specular reflectance of parabolic surface 132 is 95% or higher, and the specular reflectance of surface 135 is 20% or lower. For example, surface 135 is formed so that the specular reflectance is lowered by adjusting the surface roughness. Specifically, lens element 13 is formed so that the surface roughness of surface 135 is greater than the surface roughness of parabolic surface 132. Note that although the boundary between parabolic surface 132 and surface 135 is indicated by a two-dot chain line in FIG. 5 , the boundary may not be clear depending on the difference in surface roughness between parabolic surface 132 and surface 135.

[0037] 6 , a portion of light L12 emitted from light source 12 and incident on lens element 3 from incident surface 131 travels toward surface 135. The portion of light L12 that reaches surface 135 is diffusely reflected by surface 135.

[0038] According to the optical unit 11 of the first modification, light L12 emitted from the light source 12 and reaching a region behind and below the cutoff line forming portion 134 of the lens element 13 is diffusely reflected by the surface 135, and the intensity of the light reflected by this region is weaker than that of the light reflected by the parabolic surface 132. Therefore, it is possible to form a low-beam light distribution pattern PL in which the area below the cutoff line CL is bright and the area above the cutoff line CL is dark.

[0039] The surface 135 is formed so that the regular reflectance is low by adjusting the surface roughness, but a light absorbing film that absorbs at least a part of the light may be formed on the surface 135 .

[0040] Also, although surface 135 is formed as a parabolic surface, it may be formed as a surface having a different shape.

[0041] (Modification 2) FIG. 7 is a rear perspective view illustrating the configuration of an optical unit 21 mounted in a vehicle headlamp according to Modification 2. As shown in FIG.

[0042] The optical unit 21 according to the second modification differs from the optical unit 1 according to the above embodiment in the configuration of the area behind the cutoff line forming portion of the lens element.

[0043] 7, the optical unit 21 includes a light source 22 and a lens element 23. The light source 22 is mounted on a substrate (not shown) with its light-emitting surface facing upward. The light source 22 may be, for example, an LED or an LD.

[0044] The lens element 23 extends in the front-rear direction and is an optical component made of, for example, a transparent resin material or a glass material. The lens element 23 has an incident surface 231, a parabolic surface 232, and an exit surface 233.

[0045] The parabolic surface 232 is formed at the rear of the lens element 23. Here, the parabolic surface 232 is a paraboloid of revolution formed by rotating a parabola around an axis extending in the front-to-rear direction. The parabolic surface 232 is configured as a total reflection surface that reflects light emitted from the focus of the parabola forward as parallel light. The light source 22 is disposed near the focus of the parabolic surface 232.

[0046] A cutoff line forming portion 234 having a shape corresponding to the cutoff line of the low beam distribution pattern is provided at the rear end of the parabolic surface 232. The cutoff line forming portion 234 is provided near the focal point of the emission surface 233. In this example, the cutoff line forming portion 234 extends in the left-right direction and has a step in the center in the left-right direction.

[0047] The exit surface 233 is formed at the front of the lens element 23. The exit surface 233 is formed so as to be convex in the forward direction. The exit surface 233 refracts incident parallel light in any direction and emits the light so as to create a desired light distribution pattern.

[0048] Fig. 8 is a cross-sectional view of the optical unit 21. As illustrated in Fig. 8, a portion of light L21 emitted from the light source 22 and incident on the incident surface 231 of the parabolic surface 232 is directed toward the parabolic surface 232. The portion of light L21 that reaches the parabolic surface 232 is reflected forward by the parabolic surface 232. The portion of light L21 that reaches the exit surface 233 is emitted forward.

[0049] The lens element 23 has a protruding portion 235 that protrudes rearward beyond the parabolic surface 232 in a region rearward and below the cutoff line forming portion 234. The upper surface of the protruding portion 235 extends rearward from the cutoff line forming portion 234. The edge portion between the protruding portion 235 and the parabolic surface 232 forms the cutoff line forming portion 234.

[0050] A portion of light L22 emitted from the light source 22 and incident on the lens element 23 from the incident surface 231 travels toward a region behind and below the cutoff line forming portion 234 and is incident on the protrusion 235. A portion of light L12 incident on the protrusion 235 is reflected within the protrusion 235 and is emitted backward from the protrusion 235, for example.

[0051] According to the optical unit 21 of the second modification, light emitted from the light source 22 and directed toward a region behind and below the cutoff line forming portion 134 of the lens element 23 is guided rearward by the protrusion 235 and does not enter the exit surface 133 as parallel light. This makes it possible to form a low-beam light distribution pattern PL having a cutoff line CL.

[0052] (Modification 3) FIG. 9 is a rear perspective view illustrating the configuration of an optical unit 41 mounted in a vehicle headlamp according to Modification 3. As shown in FIG.

[0053] An optical unit 41 according to the third modification differs from the optical unit 1 according to the above embodiment in the configuration of the area behind the cutoff line forming portion of the lens element.

[0054] 9, the optical unit 41 includes a light source 42 and a lens element 43. The light source 42 is mounted on a substrate (not shown) with its light-emitting surface facing upward. The light source 42 may be, for example, an LED or an LD.

[0055] The lens element 43 extends in the front-rear direction and is an optical component made of, for example, a transparent resin material or a glass material. The lens element 43 has an incident surface 431, a parabolic surface 432, and an exit surface 433.

[0056] The parabolic surface 432 is formed at the rear of the lens element 43. Here, the parabolic surface 432 is a paraboloid of revolution formed by rotating a parabola around an axis extending in the front-to-rear direction. The parabolic surface 432 is configured as a total reflection surface that reflects light emitted from the focus of the parabola forward as parallel light. The light source 42 is disposed near the focus of the parabolic surface 432.

[0057] A cutoff line forming portion 434 having a shape corresponding to the cutoff line of the low beam distribution pattern is provided at the rear end of the parabolic surface 432. The cutoff line forming portion 434 is provided near the focal point of the emission surface 433. In this example, the cutoff line forming portion 434 extends in the left-right direction and has a step in the center in the left-right direction.

[0058] The exit surface 433 is formed at the front of the lens element 43. The exit surface 433 is formed so as to be convex in the forward direction. The exit surface 433 refracts incident parallel light in any direction and emits the light so as to create a desired light distribution pattern.

[0059] Fig. 10 is a cross-sectional view of the optical unit 41. As illustrated in Fig. 10, a portion of light L31 emitted from the light source 42 and incident on the incident surface 431 of the parabolic surface 432 is directed toward the parabolic surface 432. The portion of light L31 that reaches the parabolic surface 432 is reflected forward by the parabolic surface 432. The portion of light L31 that reaches the exit surface 433 is emitted forward.

[0060] Lens element 43 further includes second parabolic surface 435 and step portion 436. Second parabolic surface 435 is formed rearward of parabolic surface 432. Here, second parabolic surface 435 is a paraboloid of revolution formed by rotating a parabola around an axis extending in the front-to-rear direction. Second parabolic surface 435 is configured as a total reflection surface that reflects light emitted from the focus of the parabola forward as parallel light.

[0061] The step portion 436 is a flat surface perpendicular to the front-rear direction. The step portion 436 extends downward from the cutoff line forming portion 434. The second parabolic surface 435 is connected to the parabolic surface 432 via the step portion 436. That is, the lens element 43 has the second parabolic surface 435 and the step portion 436 in a region rearward and below the cutoff line forming portion 434.

[0062] 10 , the second parabolic surface 435 is formed so that the axis of the second parabolic surface 435 is common to the axis of the parabolic surface 432, and the directrix of the second parabolic surface 435 is parallel to and rearward of the directrix of the parabolic surface 432. Alternatively, the second parabolic surface 435 may be formed, for example, so that the directrix of the second parabolic surface 435 is common to the directrix of the parabolic surface 432, and the axis of the second parabolic surface 435 is parallel to and downward of the axis of the parabolic surface 432.

[0063] A portion of light L32 emitted from light source 42 and incident on lens element 3 from incident surface 431 travels toward second parabolic surface 435. The portion of light L32 that reaches second parabolic surface 435 is reflected by second parabolic surface 435 as parallel light toward exit surface 433. The light that reaches exit surface 433 and is emitted from exit surface 433 is emitted higher than the light that is reflected by parabolic surface 432 and emitted from exit surface 433.

[0064] FIG. 11 illustrates a light distribution pattern projected onto a virtual vertical screen by light emitted from the optical unit 41.

[0065] As illustrated in Figure 11, the light distribution pattern includes a low beam light distribution pattern PL formed by light reflected by the parabolic surface 432 and a light distribution pattern PC formed by light reflected by the second parabolic surface 435.

[0066] The low-beam distribution pattern PL has, at its upper end, a cutoff line CL that corresponds to the cutoff line forming portion 34 of the lens element 3. The light distribution pattern PC is formed above the low-beam distribution pattern PL. The shape of the lower end of the light distribution pattern PC corresponds to the cutoff line forming portion 34. The light distribution pattern PC is formed as a horizontally elongated light distribution pattern that spreads in the left-right direction around the V-V line at a position above and spaced apart from the cutoff line CL of the low-beam distribution pattern PL. The light distribution pattern PC is used as a light distribution pattern for OHS illumination to illuminate an overhead sign OHS installed above the road surface ahead of the vehicle.

[0067] According to the optical unit 41 of the third modification, light emitted from the light source 42 and directed toward a region rearward and downward of the cutoff line forming portion 434 of the lens element 43 is reflected by the second parabolic surface 435 toward the emission surface 433 to form the light distribution pattern PC for OHS irradiation. This makes it possible to form the low-beam light distribution pattern PL and the light distribution pattern PC for OHS irradiation with a single optical unit. Furthermore, because the light distribution pattern PC for OHS irradiation is formed using light that does not form the low-beam light distribution pattern PL, the luminous flux utilization efficiency of the light emitted from the light source 42 is improved.

[0068] (Cutoff line forming portion) In the optical units 1, 11, 21, 41 according to the above-described embodiments and modified examples, the cutoff line forming portions 34, 134, 234, 434 of the lens elements 3, 13, 23, 43 may be formed so that their radius of curvature ρ satisfies the following relational expression (1) when viewed from above.

[0069]

[0070] r is the radius of curvature of the exit surface of the lens element, and n' is the refractive index of the lens element.

[0071] The cutoff line forming portion having the radius of curvature ρ that satisfies the above relational expression (1) is formed in a curved shape that corresponds to the curvature of field on the exit surface of the lens element when viewed from above, thereby enabling the formation of a clear cutoff line.

[0072] Here, a method for calculating the relational expression (1) of the radius of curvature of the cutoff line forming portion will be described below with reference to FIGS. 12 and 13. FIG.

[0073] As shown in FIG. 12, the imaging formula by one spherical surface is expressed by the following relational expression (2).

[0074] s is the distance to the object, n is the object-side refractive index, s' is the distance to the image, n' is the image-side refractive index, and r is the radius of curvature of the spherical surface.

[0075] In a vehicle headlamp, light is emitted far into the air, so the object side is considered to be the direction of illumination, and s = ∞ and n = 1. Furthermore, n' corresponds to the refractive index of the lens element, and r corresponds to the radius of curvature of the exit surface of the lens element defined near the optical axis of the lens element. As a result, the above relational expression (2) can be expressed as the following relational expression (3).

[0076]

[0077] As shown in Figure 13, when the entire object is rotated around the center C of curvature of the spherical surface, the image point Q from a distance rotates around C with a radius of curvature ρ. From Figure 13, ρ = s' - r. Furthermore, from the above relational expression (3), the distance s' to the image can be expressed by the following relational expression (4). Therefore, the relational expression (5) for the radius of curvature ρ can be derived.

[0078]

[0079]

[0080] That is, the cutoff line CL can be formed by setting the radius of curvature of the cutoff line forming portion to be equal to the radius of curvature ρ of the image point Q of the spherical lens expressed by the above relational expression (5).

[0081] The present invention is not limited to the above-described embodiments and can be freely modified, improved, etc. The material, shape, dimensions, numerical values, form, number, location, etc. of each component in the above-described embodiments are arbitrary and not limited as long as they can achieve the present invention.

[0082] In the above-described embodiment and modified examples, a lens such as a total internal reflection (TIR) ​​lens, a compound parabolic concentrator (CPC), an elliptical mirror, or the like may be disposed between the light source and the lens element. By using such a lens, the light emitted from the light source can be efficiently incident on the parabolic surface of the lens element.

[0083] This application is based on Japanese Patent Application No. 2023-221010, filed on December 27, 2023, the contents of which are incorporated herein by reference.

Claims

1. A vehicle headlamp that forms a low-beam light distribution pattern including a cut-off line in front, comprising a light source and a lens element extending in the front-rear direction, wherein the lens element has a parabolic surface formed at the rear for reflecting the light emitted from the light source forward and an exit surface formed at the front for emitting the light reflected by the parabolic surface forward; the light source is provided near the focal point of the parabolic surface; a cut-off line forming portion having a shape corresponding to the cut-off line is provided at the rear end of the parabolic surface; the cut-off line forming portion is provided near the focal point of the exit surface; and at least one of a region behind the cut-off line forming portion of the lens element and a region closer to the light source than the cut-off line forming portion is configured not to contribute the light emitted from the light source to the low-beam light distribution pattern.

2. The vehicle headlamp according to claim 1, wherein at least one of a region behind the cut-off line forming portion of the lens element and a region closer to the light source than the cut-off line forming portion is configured not to guide light toward the exit surface.

3. The vehicle headlamp according to claim 1 or 2, wherein the lens element has a flat surface orthogonal to the front-rear direction in at least one of a region behind the cut-off line forming portion of the lens element and a region closer to the light source than the cut-off line forming portion.

4. When the radius of curvature of the exit surface is r and the refractive index of the lens element is n, the cutoff line forming portion is formed such that the radius of curvature ρ satisfies the following relational expression (1) when viewed from a direction orthogonal to the longitudinal direction of the lens element. The vehicle headlamp according to claim 1 or claim 2.

5. The vehicle headlamp according to claim 1, wherein the lens element has a second parabolic surface connected to the parabolic surface via a step portion, and the second parabolic surface is formed behind the parabolic surface.

6. The vehicle headlamp according to claim 1 or 2, wherein the specular reflectance of a surface formed in at least one of a region behind the cut-off line forming portion of the lens element and a region closer to the light source than the cut-off line forming portion is lower than the specular reflectance of the parabolic surface.

7. The vehicle headlamp according to claim 1 or 2, wherein the lens element has a protruding portion protruding behind the parabolic surface in at least one of a region behind the cut-off line forming portion of the lens element and a region closer to the light source than the cut-off line forming portion.

Images