Vehicle headlight

Abstract

This vehicle headlight (1) comprises a high lamp unit (HU) that emits light of an additional light distribution pattern (PAH) that is added to a low beam light distribution pattern (PL) and forms a high beam light distribution pattern. The high lamp unit (HU) includes: a first unit (30) that emits light of a first light distribution pattern (P1); and a second unit (40) that emits light of a second light distribution pattern (P2) that is superimposed on a portion including a center (P1c) of the first light distribution pattern (P1) and forms the additional light distribution pattern (PAH).

Description

Vehicle headlights

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

[0002] A known vehicle headlamp includes a high-beam lamp unit that emits light in an additional light distribution pattern that is added to a low-beam light distribution pattern to form a high-beam light distribution pattern. Patent Document 1 below discloses such a vehicle headlamp.

[0003] Japanese Patent Application Laid-Open No. 2003-7104

[0004] In the vehicle headlamp of Patent Document 1, the light intensity distribution of the additional light distribution pattern is strongest in the center. The additional light distribution pattern having this intensity distribution is formed by a high-side lamp unit, which is composed of one light source and one reflector that reflects the light emitted from the light source. With such a high-side lamp unit, the light intensity distribution of the additional light distribution pattern can be adjusted by, for example, adjusting the shape of the reflector. However, because the additional light distribution pattern is formed by a single lamp unit, it tends to be difficult to fine-tune the light intensity distribution.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle headlamp that can easily form an additional light distribution pattern having a desired intensity distribution.

[0006] In order to achieve the above object, the vehicle headlamp of the present invention comprises a high beam lighting unit that emits light of an additional light distribution pattern that is added to a low beam light distribution pattern to form a high beam light distribution pattern, and the high beam lighting unit is characterized by including a first unit that emits light of a first light distribution pattern, and a second unit that emits light of a second light distribution pattern that is superimposed on a portion including the center of the first light distribution pattern to form the additional light distribution pattern.

[0007] In this vehicle headlamp, an additional light distribution pattern is formed by superimposing a second light distribution pattern formed by the light of the second unit on a portion, including the center, of a first light distribution pattern formed by the light of the first unit. This makes it easy to make the central portion of the light intensity distribution of the additional light distribution pattern the strongest. Furthermore, the light intensity distribution of the additional light distribution pattern can be adjusted by adjusting the light intensity distribution of the first light distribution pattern and the light intensity distribution of the second light distribution pattern. Therefore, with this vehicle headlamp, an additional light distribution pattern with a desired intensity distribution can be easily formed compared to when an additional light distribution pattern is formed using only the light of the first unit.

[0008] An upper edge of the second light distribution pattern may be located above an upper edge of the first light distribution pattern.

[0009] With this configuration, it is possible to easily irradiate light to an upper area at the center in the left-right direction in front of the vehicle.

[0010] Alternatively, an upper edge of the second light distribution pattern may coincide with an upper edge of the first light distribution pattern.

[0011] According to this configuration, the upper edge of the additional light distribution pattern can be more easily made clear compared to a case where the upper edge of the second light distribution pattern does not coincide with the first light distribution pattern.

[0012] A lower edge of the second light distribution pattern may be located lower than a lower edge of the first light distribution pattern.

[0013] Alternatively, a lower edge of the second light distribution pattern may coincide with a lower edge of the first light distribution pattern.

[0014] The lower edge of the first light distribution pattern may be located below the cutoff line of the low beam light distribution pattern, and the lower edge of the second light distribution pattern may be located between the lower edge of the first light distribution pattern and the cutoff line.

[0015] With this configuration, it is easier to prevent an area that is too bright from being formed in the area where the low beam light distribution pattern and the additional light distribution pattern overlap, compared to when the lower edge of the first light distribution pattern is located below the cutoff line of the low beam light distribution pattern and the lower edge of the second light distribution pattern is located below the lower edge of the first light distribution pattern.

[0016] The first light distribution pattern may overlap with the low beam light distribution pattern, and the second light distribution pattern may not overlap with the low beam light distribution pattern.

[0017] With this configuration, it is easier to prevent an area that is too bright from being formed in the area where the low beam light distribution pattern and the additional light distribution pattern overlap, compared to when the first light distribution pattern and the second light distribution pattern overlap with the low beam light distribution pattern.

[0018] Each of the first unit and the second unit may include a light source that emits light downward, a projection lens that is positioned in front of the light source, and a reflector that is positioned to cover the light source from below and reflects the light emitted from the light source toward the projection lens.

[0019] In this case, the reflector of the first unit and the reflector of the second unit may be aligned in the left-right direction.

[0020] With this configuration, it is possible to prevent the high lamp unit from becoming larger in the vertical direction.

[0021] As described above, according to the present invention, a vehicle headlamp can be provided that can easily form an additional light distribution pattern having a desired intensity distribution.

[0022] FIG. 1 is a schematic diagram of a vehicle headlamp according to an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view schematically showing a low-beam lamp unit. FIG. 3 is a diagram showing a low-beam light distribution pattern according to the embodiment. FIG. 4 is a vertical cross-sectional view schematically showing a first unit. FIG. 5 is a vertical cross-sectional view schematically showing a second unit. FIG. 6 is a diagram showing an additional light distribution pattern according to the embodiment, similar to FIG. 3. FIG. 7 is a diagram showing an additional light distribution pattern according to a first modified example, similar to FIG. 6. FIG. 8 is a diagram showing an additional light distribution pattern according to a second modified example, similar to FIG. 6. FIG. 9 is a diagram showing a portion of an additional light distribution pattern according to a third modified example.

[0023] Preferred embodiments of a vehicle headlamp according to the present invention will be described in detail below with reference to the drawings. The embodiments exemplified below are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be modified and improved within the scope of the claims without departing from the spirit thereof. Note that in the drawings referred to below, the dimensions of each component may be changed to facilitate understanding. Also, in the drawings, for ease of viewing, similar components may be denoted with reference numerals only in some cases, and some reference numerals may be omitted.

[0024] FIG. 1 is a schematic diagram of a vehicle headlight in an embodiment. The vehicle headlight 1 is generally provided on each of the left and right sides of the front of the vehicle, and the left and right vehicle headlights 1 are configured to be approximately symmetrical in the left-right direction. Therefore, in this embodiment, the right vehicle headlight 1 will be described. In this specification, "right" means the right side in the forward direction of the vehicle, and "left" means the left side in the forward direction. The vehicle in this embodiment is an automobile.

[0025] The vehicle headlamp 1 includes a housing 10, a low lamp unit LU, and a high lamp unit HU. The housing 10 includes a housing 11 and a front cover 12. The housing 11 is configured in a box shape with an opening at the front, and the front cover 12 is fixed to the housing 11 so as to cover the opening. In this way, an accommodation space surrounded by the housing 11 and the front cover 12 is formed in the housing 10, and the low lamp unit LU and the high lamp unit HU are disposed in this accommodation space. The front cover 12 transmits light emitted from the low lamp unit LU and the high lamp unit HU.

[0026] The low lamp unit LU emits a low beam, and the high lamp unit HU emits light having an additional light distribution pattern that is added to the low beam light distribution pattern to form a high beam light distribution pattern. In this embodiment, the low lamp unit LU is disposed further outward from the high lamp unit HU and is aligned with the high lamp unit HU in the left-right direction. The light distribution pattern is, for example, a light pattern drawn by light irradiated onto a virtual vertical screen in front of the vehicle, and includes not only the outline of the light but also the light intensity distribution. The virtual vertical screen is located, for example, 25 m ahead of the vehicle.

[0027] 2 is a vertical cross-sectional view showing the low lamp unit LU. The low lamp unit LU of this embodiment mainly comprises a light source 21, a reflector 22, a projection lens 23, and a shade 24.

[0028] The light source 21 of this embodiment emits light La upward, which becomes light for a low-beam light distribution pattern. An example of the light source 21 is a light-emitting diode (LED). The light source 21 is fixed to a first mounting surface of a heat sink (not shown). The power supply to the light source 21 is switched on and off by a light control circuit (not shown).

[0029] The reflector 22 is a member that reflects the light La emitted from the light source 21. In this embodiment, the reflector 22 is a curved, plate-like member that is fixed to a heat sink (not shown) so as to cover the light source 21 from above. The surface of the reflector 22 facing the light source 21 is a reflective surface 22r that reflects the light La. The reflective surface 22r is based on an ellipsoidal surface of revolution, with the light source 21 located at or near the first focal point of this ellipsoidal surface, and the second focal point of this ellipsoidal surface located forward of the first focal point. At least a portion of the light La is reflected by the reflective surface 22r toward the projection lens 23, which is located forward of the light source 21 and the reflector 22.

[0030] The projection lens 23 is a lens that adjusts the divergence angle of incident light. In this embodiment, the projection lens 23 is a biconvex lens with convex entrance and exit surfaces. The rear focal point of the projection lens 23 is located at or near the second focal point of the reflecting surface 22r of the reflector 22. In other words, the low lamp unit LU of this embodiment is a PES (Projector Ellipsoid System) type lamp unit.

[0031] The shade 24 is a non-transparent member disposed between the reflecting surface 22r and the projection lens 23. In this embodiment, the shade 24 is a plate-like member extending vertically and horizontally. The upper end surface of the shade 24 is a flat surface extending generally horizontally and is located at or near the second focal point of the elliptical curve of the reflecting surface 22r. As shown in FIG. 1 , a step portion 25 is formed on the upper end surface of the shade 24. A portion of the light La emitted from the light source 21 and reflected by the reflector 22 and a portion of the light traveling forward from the light source 21 are irradiated onto the upper end portion of the shade 24, and the light is blocked. Another portion of the light La travels from the reflecting surface 22r toward the projection lens 23 without being blocked by the shade 24, and enters the projection lens 23. Another portion of the light La directly enters the projection lens 23. In this way, light having a low beam light distribution pattern in which a cutoff line corresponding to the shape of the upper end of the shade 24 is formed is transmitted through the projection lens 23 and emitted toward the front of the vehicle. Note that the configuration of the shade 24 is not limited as long as it is configured to form a cutoff line, and for example, the shade 24 may be part of a heat sink.

[0032] FIG. 3 is a diagram showing a low-beam light distribution pattern according to this embodiment. In FIG. 3, S denotes a horizontal line, V denotes a vertical line passing through the center of the vehicle in the lateral direction, and the low-beam light distribution pattern PL formed on a virtual vertical screen positioned 25 m ahead of the vehicle is indicated by a thick line. The reflecting surface 22r of the reflector 22 is shaped so that the light distribution pattern of light La from the light source 21 becomes this low-beam light distribution pattern PL. The low-beam light distribution pattern PL according to this embodiment is suitable for countries and regions where vehicles drive on the left side of the road. The cutoff line CL, which is the upper edge of the low-beam light distribution pattern PL, corresponds to the shape of the upper end of the shade 24, and the cutoff line CL has a step portion CLa corresponding to the step portion 25. The step portion CLa is a line that slopes upward toward the left from an elbow point EP located below the horizontal line S and on or near the vertical line V. The portion of the cutoff line CL other than the step portion CLa extends generally horizontally. The hot zone HZL, which is the area in the low beam light distribution pattern PL where the light intensity is highest, is located near the elbow point EP, and the light intensity in the low beam light distribution pattern PL decreases from the hot zone HZL outward.

[0033] Next, the high lamp unit HU will be described.

[0034] 1 , the high lamp unit HU of this embodiment includes a first unit 30 that emits light having a first light distribution pattern and a second unit 40 that emits light having a second light distribution pattern. In this embodiment, the first unit 30 is disposed between the low lamp unit LU and the second unit 40, and is aligned with the second unit 40 in the left-right direction. As will be described in detail later, an additional light distribution pattern is formed by superimposing the first light distribution pattern and the second light distribution pattern.

[0035] 4 is a vertical cross-sectional view schematically showing the first unit 30. The first unit 30 of this embodiment is a PES type lamp unit similar to the low lamp unit LU, and includes a light source 31, a reflector 32, and a projection lens 33 as its main components.

[0036] The light source 31 of this embodiment emits light Lb downward, which becomes part of the additional light distribution pattern. An example of the light source 31 is an LED. The light source 31 is fixed to a second mounting surface of a heat sink (not shown). The power supply to the light source 31 is switched on and off by a light control circuit (not shown), similar to the light source 21.

[0037] The reflector 32 is a member that reflects light Lb emitted from the light source 31. In this embodiment, the reflector 32 is a curved, plate-like member that is fixed to a heat sink (not shown) so as to cover the light source 31 from below. The surface of the reflector 32 facing the light source 31 is a reflective surface 32r that reflects light Lb. The reflective surface 32r is based on an ellipsoidal surface of revolution, with the light source 31 located at or near the first focal point of this ellipsoidal surface, and the second focal point of this ellipsoidal surface located forward of the first focal point. At least a portion of the light Lb is reflected by the reflective surface 32r toward a projection lens 33 that is located forward of the light source 31 and the reflector 32.

[0038] The projection lens 33 of this embodiment is a biconvex lens with convex incident and exit surfaces, similar to the projection lens 23, and the rear focal point of the projection lens 33 is located at or near the second focal point of the reflecting surface 32r.

[0039] In this embodiment, a portion of the light Lb from the light source 31 is reflected by the reflecting surface 32r of the reflector 32 toward the projection lens 33 and enters the projection lens 33, and another portion of the light Lb directly enters the projection lens 33. In this way, the light having the first light distribution pattern passes through the projection lens 33 and is emitted forward of the vehicle.

[0040] 5 is a vertical cross-sectional view schematically showing the second unit 40. Like the first unit 30, the second unit 40 of this embodiment is a PES-type lamp unit, and includes a light source 41, a reflector 42, and a projection lens 43 as its main components.

[0041] The light source 41 of this embodiment emits light Lc downward, which becomes another part of the additional light distribution pattern. Examples of the light source 41 include an LED. The light source 41 is fixed to a third mounting surface of a heat sink (not shown). In this embodiment, the third mounting surface and the second mounting surface to which the light source 31 is fixed are located on the same plane. That is, the light source 41 and the light source 31 are located on the same plane. The light source 41 is located to the left of the light source 31, and the light source 41 and the light source 31 are aligned in the left-right direction. The positional relationship between the light source 41 and the light source 31 is not limited. The light source 41 is the same as the light source 31, and the intensity and divergence angle of the light Lc emitted from the light source 41 are the same as the intensity and divergence angle of the light Lb emitted from the light source 31, but may be different from those of the light source 41 and the light source 31. The power on / off switching of the light source 41 is controlled by a light control circuit (not shown), similar to the light source 31.

[0042] The reflector 42 is a member that reflects the light Lc emitted from the light source 41. In this embodiment, the reflector 42 is a curved, plate-like member that is fixed to a heat sink (not shown) so as to cover the light source 41 from below. The surface of the reflector 42 facing the light source 41 is a reflective surface 42r that reflects the light Lc. The reflective surface 42r is based on an ellipsoidal surface that is different from the reflective surface 32r. The light source 41 is located at or near the first focus of this ellipsoidal surface, and the second focus of this ellipsoidal surface is located forward of the first focus. The reflector 42 is located to the left of the reflector 32, and the reflectors 42 and 32 are aligned in the left-right direction. The reflective surface 42r is larger than the reflective surface 32r, but the sizes of the reflective surfaces 42r and 32r are not limited. At least a portion of the light Lc is reflected by the reflecting surface 42r toward the projection lens 43 disposed in front of the light source 41 and the reflector 42.

[0043] The projection lens 43 is a biconvex lens with convex incident and exit surfaces, similar to the projection lens 33, and the rear focal point of the projection lens 43 is located at or near the second focal point of the reflecting surface 42r. The projection lens 43 is located to the left of the projection lens 33, and the projection lens 43 and the projection lens 33 are aligned in the left-right direction.

[0044] In this embodiment, a portion of the light Lc from the light source 41 is reflected by the reflecting surface 42r of the reflector 42 toward the projection lens 43 and enters the projection lens 43, and another portion of the light Lc is directly incident on the projection lens 43. In this way, the light having the second light distribution pattern passes through the projection lens 43 and is emitted forward of the vehicle.

[0045] Fig. 6 is a diagram similar to Fig. 3 showing the additional light distribution pattern of this embodiment. As shown in Fig. 6, the additional light distribution pattern PAH is formed by a first light distribution pattern P1 formed by light Lb emitted from the first unit 30 and a second light distribution pattern P2 formed by light Lc emitted from the second unit 40. In Fig. 6, the first light distribution pattern P1 is indicated by a dashed line, the second light distribution pattern P2 is indicated by a dashed line, and the low beam light distribution pattern PL is indicated by a broken line. For ease of viewing, the first light distribution pattern P1 and the second light distribution pattern P2 are slightly offset in the vertical direction with respect to the additional light distribution pattern PAH.

[0046] In this embodiment, the hot zone HZP1 in the first light distribution pattern P1 is located below the center P1c of the first light distribution pattern P1 and above the horizontal line S. The center P1c is the intersection of a vertical line passing through the center of the first light distribution pattern P1 in the left-right direction and a horizontal line passing through the center of the first light distribution pattern P1 in the up-down direction. The light intensity in the first light distribution pattern P1 decreases from the hot zone HZP1 toward the outside. The upper edge P1ue of the first light distribution pattern P1 is curved so as to be convex upward, and the lower edge P1de of the first light distribution pattern P1 is curved so as to be convex downward. The left and right edges P1se of the first light distribution pattern P1 are straight lines that are generally parallel to the vertical direction.

[0047] The second light distribution pattern P2 overlaps a portion of the first light distribution pattern P1, including its center P1c. In this embodiment, the center of the second light distribution pattern P2 coincides with the center P1c, and a hot zone HZP1 is located within a hot zone HZP2 in the second light distribution pattern P2. The light intensity in the second light distribution pattern P2 decreases from the hot zone HZP2 outward. Therefore, the hot zone in the additional light distribution pattern PAH is the region where the hot zone HZP1 and the hot zone HZP2 overlap, and the light intensity in the additional light distribution pattern PAH decreases from this region outward.

[0048] The upper edge P2ue of the second light distribution pattern P2 coincides with the upper edge P1ue of the first light distribution pattern P1. The lower edge P2de of the second light distribution pattern P2 coincides with the lower edge P1de of the first light distribution pattern P1. The left and right edges P2se of the second light distribution pattern P2 are straight lines parallel to the vertical direction and are located between the left and right edges P1se of the first light distribution pattern P1. The entire second light distribution pattern P2 overlaps with the first light distribution pattern P1, and the outer shape of the additional light distribution pattern PAH is the same as the outer shape of the first light distribution pattern P1. The lower edges P1de and P2de of the first and second light distribution patterns P1 and P2 are located below the cutoff line CL, and the first and second light distribution patterns P1 and P2 overlap with the low-beam light distribution pattern PL. Furthermore, the hot zone HZL of the low beam light distribution pattern PL overlaps with the first light distribution pattern P1 and the second light distribution pattern P2.

[0049] That is, the shapes, positions, orientations, etc. of the reflector 32 of the first unit 30 and the reflector 42 of the second unit 40 are adjusted so that such first light distribution pattern P1 and second light distribution pattern P2 are formed. Then, by emitting light having the additional light distribution pattern PAH from the high lamp unit HU and emitting a low beam from the low lamp unit LU, the additional light distribution pattern PAH is added to the low beam light distribution pattern PL, thereby forming a high beam light distribution pattern.

[0050] As described above, the vehicle headlamp 1 of this embodiment includes a high-light lamp unit HU that emits light of the additional light distribution pattern PAH. The high-light lamp unit HU includes a first unit 30 that emits light of the first light distribution pattern P1 and a second unit 40 that emits light of the second light distribution pattern P2. The additional light distribution pattern PAH is formed by superimposing the second light distribution pattern P2 on a portion of the first light distribution pattern P1, including the center P1c. This makes it easy to make the central portion of the light intensity distribution of the additional light distribution pattern PAH the strongest. Furthermore, the light intensity distribution of the additional light distribution pattern PAH can be adjusted by adjusting the light intensity distribution of the first light distribution pattern P1 and the light intensity distribution of the second light distribution pattern P2. Therefore, the vehicle headlamp 1 of this embodiment makes it easier to form an additional light distribution pattern PAH with a desired intensity distribution, compared to when the additional light distribution pattern PAH is formed using only light from the first unit 30.

[0051] In the vehicle headlamp 1 of this embodiment, the first unit 30 and the second unit 40 each include a light source 31, 41, a projection lens 33, 43, and a reflector 32, 42. The light source 31, 41 emits light Lb, Lc downward. The projection lenses 33, 43 are disposed forward of the light source 31, 41. The reflectors 32, 42 are disposed to cover the light source 31, 41 from below and reflect the light Lb, Lc emitted from the light source 31, 41 toward the projection lens 33, 43. The reflector 32 of the first unit 30 and the reflector 42 of the second unit 40 are aligned in the left-right direction. Therefore, the vehicle headlamp 1 of this embodiment can prevent the high lamp unit HU from becoming large in the vertical direction. The reflectors 32 and 42 do not have to be aligned in the left-right direction; for example, the first unit 30 and the second unit 40 may be aligned in the up-down direction.

[0052] In the vehicle headlamp 1 of this embodiment, the upper edge P2ue of the second light distribution pattern P2 coincides with the upper edge Piue of the first light distribution pattern P1. Therefore, according to the vehicle headlamp 1 of this embodiment, it is easier to make the upper edge of the additional light distribution pattern PAH clearer than when the upper edge P2ue does not coincide with the upper edge Piue.

[0053] Although the present invention has been described above using the above embodiment as an example, the present invention is not limited to this.

[0054] For example, in the above embodiment, an example was described in which the upper edge P2ue of the second light distribution pattern P2 coincides with the upper edge P1ue of the first light distribution pattern P1, and the lower edge P2de of the second light distribution pattern P2 coincides with the lower edge P1de of the first light distribution pattern P1. However, as long as the second light distribution pattern P2 is superimposed on a portion of the first light distribution pattern P1, including the center P1c, to form the additional light distribution pattern PAH, the positional relationship between the upper edge P2ue and the upper edge P1ue and the lower edge P2de and the lower edge P1de is not limited. Below, first to third modified examples will be described in which this positional relationship differs from the positional relationship of the above embodiment. Note that components that are the same as or equivalent to those in the above embodiment will be assigned the same reference numerals, and redundant description will be omitted, unless otherwise specified.

[0055] First, a first modified example will be described. FIG. 7 is a diagram similar to FIG. 6 showing an additional light distribution pattern PAH in the first modified example. As shown in FIG. 7, in the additional light distribution pattern PAH of this modified example, the second light distribution pattern P2 differs from the second light distribution pattern P2 of the above embodiment. In this modified example, the upper edge P2ue of the second light distribution pattern P2 is located above the upper edge P1ue of the first light distribution pattern P1. Furthermore, the lower edge P2de of the second light distribution pattern P2 is located below the lower edge P1de of the first light distribution pattern P1. Even with such a positional relationship between the upper edge P1ue and the upper edge P2ue and the positional relationship between the lower edge P1de and the lower edge P2de, an additional light distribution pattern PAH having a desired intensity distribution can be easily formed compared to forming the additional light distribution pattern PAH using only light from the first unit 30, as in the above embodiment. Furthermore, because the upper edge P2ue is located above the upper edge P1ue, it is easier to irradiate light above the center in the left-right direction in front of the vehicle.

[0056] Next, a second modified example will be described. FIG. 8 is a diagram similar to FIG. 6 showing an additional light distribution pattern in the second modified example. As shown in FIG. 8, in the additional light distribution pattern PAH of this modified example, the second light distribution pattern P2 differs from the second light distribution pattern P2 of the above embodiment. In this modified example, the upper edge P2ue of the second light distribution pattern P2 is located below the upper edge P1ue of the first light distribution pattern P1. Furthermore, the lower edge P2de of the second light distribution pattern P2 is located above the lower edge P1de of the first light distribution pattern P1. Even with such a positional relationship between the upper edge P1ue and the upper edge P2ue and the positional relationship between the lower edge P1de and the lower edge P2de, an additional light distribution pattern PAH having a desired intensity distribution can be easily formed compared to when the additional light distribution pattern PAH is formed using only light from the first unit 30, as in the above embodiment.

[0057] In this modified example, the lower edge P2de is located above the cutoff line CL. That is, the first light distribution pattern P1 overlaps with the low beam light distribution pattern PL, and the second light distribution pattern P2 does not overlap with the low beam light distribution pattern PL. Therefore, the vehicle headlamp 1 of this modified example can more easily prevent an overly bright area from being formed in the area where the low beam light distribution pattern PL and the additional light distribution pattern PAH overlap, compared to when the first light distribution pattern P1 and the second light distribution pattern P2 overlap with the low beam light distribution pattern PL. In this modified example, the lower edge P2de extends along the cutoff line CL at a predetermined distance from the cutoff line CL, but this is not limited to this. For example, the lower edge P2de may coincide with the cutoff line CL. Alternatively, the lower edge P1de may coincide with the cutoff line CL.

[0058] Next, a third modified example will be described. FIG. 9 is a diagram showing a portion of the additional light distribution pattern PAH in the third modified example, and is a diagram showing a portion including the lower edge P2de of the second light distribution pattern P2. Similar to FIG. 6 , FIG. 9 shows the low-beam light distribution pattern PL, the first light distribution pattern P1, and the third light distribution pattern. As shown in FIG. 9 , in the additional light distribution pattern PAH of this modified example, the position of the lower edge P2de of the second light distribution pattern P2 is different from the position of the lower edge P2de in the second modified example. In this modified example, the lower edge P1de of the first light distribution pattern P1 is located below the cutoff line CL, as in the second modified example, but the lower edge P2de of the second light distribution pattern P2 is located between the lower edge P1de and the cutoff line CL. Even with this positional relationship between the lower edge P1de and the lower edge P2de, an additional light distribution pattern PAH having a desired intensity distribution can be easily formed, as compared to when the additional light distribution pattern PAH is formed using only light from the first unit 30, as in the above embodiment. Furthermore, compared to when the lower edge P1de is located below the cutoff line CL and the lower edge P2de is located below the lower edge P1de, it is easier to prevent an area that becomes too bright from being formed in the area where the low beam light distribution pattern PL and the additional light distribution pattern PAH overlap.

[0059] In this modification, the lower edge P1de is located below the hot zone HZL of the low beam light distribution pattern PL, as in the second modification, but the lower edge P2de passes between the lower edge P1de and the hot zone HZL. Note that at least one of the lower edges P1de and P2de may overlap the hot zone HZL. Furthermore, at least one of the lower edges P1de and P2de may pass between the cutoff line CL and the hot zone HZL.

[0060] In this modification, the upper edge P2ue of the second light distribution pattern P2 may coincide with the upper edge P1ue of the first light distribution pattern P1, similar to the upper edge P2ue in the first embodiment shown in Fig. 6. The upper edge P2ue of the second light distribution pattern P2 may be located above the upper edge P1ue of the first light distribution pattern P1, similar to the upper edge P2ue in the first modification shown in Fig. 7. The upper edge P2ue of the second light distribution pattern P2 may be located below the upper edge P1ue of the first light distribution pattern P1, similar to the upper edge P2ue in the second modification shown in Fig. 8.

[0061] In the above embodiment and the first and third modified examples, both the first and second light distribution patterns P1 and P2 overlap with the hot zone HZL of the low-beam light distribution pattern PL, and in the above second modified example, only the first light distribution pattern P1 overlaps with the hot zone HZL. However, it is not necessary for both the first and second light distribution patterns P1 and P2 to overlap with the hot zone HZL, and only the second light distribution pattern P2 may overlap with the hot zone HZL.

[0062] In the above embodiment, the center of the second light distribution pattern P2 coincides with the center P1c of the first light distribution pattern P1, and the entire hot zone HZP1 of the first light distribution pattern P1 is located within the hot zone HZP2 of the second light distribution pattern P2. However, the center of the second light distribution pattern P2 does not have to coincide with the center P1c. Furthermore, at least a portion of the hot zone HZP1 does not have to overlap with the hot zone HZP2, and the entire hot zone HZP2 may be located within the hot zone HZP1.

[0063] In the above embodiment, the low-beam light distribution pattern PL is described as having a step portion CLa formed in the cutoff line CL. However, the cutoff line CL may be, for example, a linear line that is substantially parallel to the horizontal direction and does not have a step portion CLa.

[0064] In the above embodiment, the low lamp unit LU, the first unit 30, and the second unit 40 are PES type lamp units. However, the configurations of the low lamp unit LU, the first unit 30, and the second unit 40 are not limited thereto, and may be parabolic or direct type lamp units, for example.

[0065] In the above embodiment, the low lamp unit LU and the high lamp unit HU are arranged side by side in the left-right direction. However, the low lamp unit LU and the high lamp unit HU may be arranged side by side in the up-down direction, for example.

[0066] According to the present invention, a vehicle headlamp that can easily form an additional light distribution pattern having a desired intensity distribution is provided, and can be used in fields such as vehicle headlamps for automobiles and the like.

Claims

1. A vehicle headlamp comprising a high-beam lamp unit that emits light of an additional light distribution pattern which is added to a low-beam light distribution pattern to form a high-beam light distribution pattern, the high-beam lamp unit including a first unit that emits light of a first light distribution pattern and a second unit that emits light of a second light distribution pattern which is superimposed on a part including the center of the first light distribution pattern to form the additional light distribution pattern.

2. The vehicle headlamp according to claim 1, wherein an upper edge of the second light distribution pattern is located above an upper edge of the first light distribution pattern.

3. The vehicle headlamp according to claim 1, wherein an upper edge of the second light distribution pattern coincides with an upper edge of the first light distribution pattern.

4. The vehicle headlamp according to claim 1, wherein a lower edge of the second light distribution pattern is located below a lower edge of the first light distribution pattern.

5. The vehicle headlamp according to claim 1, wherein a lower edge of the second light distribution pattern coincides with a lower edge of the first light distribution pattern.

6. The vehicle headlamp according to claim 1, wherein a lower edge of the first light distribution pattern is located below a cut-off line of the low-beam light distribution pattern, and a lower edge of the second light distribution pattern is located between the lower edge of the first light distribution pattern and the cut-off line.

7. The vehicle headlamp according to claim 1, wherein the first light distribution pattern overlaps with the low-beam light distribution pattern, and the second light distribution pattern does not overlap with the low-beam light distribution pattern.

8. Each of the first unit and the second unit includes a light source that emits light downward, a projection lens disposed in front of the light source, and a reflector disposed so as to cover the light source from below and reflect the light emitted from the light source toward the projection lens.

9. The vehicle headlamp according to claim 8, wherein the reflectors of the first unit and the second unit are arranged side by side in the left-right direction.

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