JP2009181845A - Vehicular headlight - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular headlight with a projection lens superior in machinability and free from chromatic aberration. <P>SOLUTION: The projection lens 14 of the vehicular headlight 10 consists of the followings molded integrally therewith: a first projection lens member 15 arranged on the upper part and formed of a material having a great refractive index; and a second projection lens member 16 arranged on the lower part and formed of a material having a smaller refractive index than the first projection lens member 15. Thus, light is injected partially to the upper side, and then emitted while being refracted downward from the light injected to the lower side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a projector-type vehicle headlamp including a light source, a projection lens, a reflector, and an optical control member.

  In conventional projector-type vehicle headlamps, light that deviates from the paraxial region due to chromatic aberration of the projection lens is dispersed, and a rainbow pattern appears in the vicinity of the cut line of the light distribution, resulting in reduced visibility. It is known. This occurs because the light incident on the periphery of the projection lens has a spectral phenomenon due to the chromatic aberration of the lens, and the blue light is refracted to the optical axis side than the red light. As a result, blue aberration is conspicuous in the region near the lower edge of the lens, red aberration is conspicuous in the region near the upper edge of the lens, and color fringes are generated in the vicinity of the cut line.

To solve this problem, the projection when cut by the horizontal plane including the optical axis, compared to the amount of change in the rear focal length of the portion belonging to the lens periphery when cut by the vertical plane including the optical axis. There is known a vehicular headlamp having a projection lens in which a change amount of a rear focal length of a portion belonging to a lens peripheral portion is increased and chromatic aberration is hardly generated. (For example, Patent Document 1)
JP-A-6-84401

  However, in the vehicle headlamp disclosed in Patent Document 1, in order to prevent chromatic aberration from occurring, the amount of change in the rear focal length around the projection lens is changed between the vertical plane including the optical axis and the horizontal plane. Therefore, the shape of the periphery of the projection lens is a substantially elliptical shape that is asymmetric in the vertical direction. The central part of the lens is an aspherical lens having rotational symmetry, and the lens peripheral part is an asymmetrical substantially elliptical shape with different focal lengths. There is a problem that a mold or the like used in the manufacture of an aspheric lens having the above cannot be used, and is not suitable for mass production.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a vehicle headlamp including a projection lens that is excellent in processability and does not cause chromatic aberration.

The object of the present invention is to provide a light source, a projection lens disposed on an optical axis extending in the vehicle front-rear direction, a reflector that reflects light from the light source forward and toward the optical axis, and the projection lens. An optical control member disposed between the light source and configured to block or reflect a part of the reflected light from the reflector to form a light distribution pattern, and a vehicle headlamp,
The projection lens includes a refracting portion made of a plurality of materials that refracts and emits light incident upward from the incident light that is larger than the light incident downward. This is achieved by a vehicle headlamp.

  According to the vehicle headlamp configured as described above, the light from the light source is reflected toward the front by the reflector toward the optical axis, and a part of the reflected light from the reflector is blocked or reflected by the optical control member. A pattern is formed and incident on the projection lens. Of the light incident on the projection lens, the upper light is largely refracted downward by the refracting unit, so the blue light and red light of the light distribution pattern are mixed into white light, and the red light is conspicuous. Can be eliminated. Thereby, since it is not necessary to process the projection lens into a complicated shape, it is possible to obtain a vehicle headlamp including a projection lens that is excellent in processability and does not cause chromatic aberration.

  In the vehicular headlamp configured as described above, the projection lens preferably includes a plurality of lens members having different refractive indexes above and below the light exit surface or the incident surface.

  According to the vehicle headlamp having such a configuration, the projection lens includes the plurality of lens members having different refractive indexes at the upper and lower sides on the light emission surface or the incident surface, thereby mechanically integrating the plurality of lens members. By combining them together or integrally molding them, it can be easily manufactured with existing molding equipment used conventionally.

  Further, in the vehicle headlamp configured as described above, the optical control member blocks a part of the reflected light from the reflector toward the rear focal point of the projection lens and the rear thereof, thereby forming the cut line of the light distribution pattern. The projection lens is preferably composed of at least two types of lens members having different refractive indexes so that the refractive index is higher in the upper part than in the lower part.

  According to the vehicle headlamp having such a configuration, the optical control member blocks the rear focal point of the projection lens from the reflector and a part of the reflected light toward the rear thereof to form a cut line of the light distribution pattern. When the light / dark division is set, the light incident on the upper lens member out of the light incident on the projection lens has a large refractive index, so that the focal length is converted to be short and emitted. Therefore, the blue light and red light of the cut line of the light distribution pattern are mixed to become white light, and the red light is not conspicuous so that chromatic aberration does not occur.

  Further, in the vehicle headlamp having the above-described configuration, the optical control member reflects the light source pattern by reflecting a part of reflected light from the reflector toward the rear focal point of the projection lens and the rear thereof toward the upper front. The projection lens is characterized in that it is composed of at least two types of lens members having different refractive indexes so that the upper portion has a higher refractive index than the lower portion.

  According to the vehicle headlamp having such a configuration, the optical control member reflects the rear focal point of the projection lens and a part of the reflected light directed rearward from the reflector toward the upper front, thereby cutting the light distribution pattern. When the light and dark boundaries are set by forming a line, the light incident on the upper lens member out of the light incident on the projection lens has a large refractive index, so that the focal length is converted to be short and emitted. . Therefore, the blue light and red light of the cut line of the light distribution pattern are mixed to become white light, and the red light is not conspicuous so that chromatic aberration does not occur.

  According to the vehicular headlamp according to the present invention, there is provided a vehicular headlamp including a projection lens that is excellent in workability and does not cause chromatic aberration.

  Hereinafter, a plurality of preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a longitudinal sectional view of a vehicle headlamp according to the present invention, and FIG. 2 is a schematic view showing a projection lens according to a first embodiment of the present invention.

  As shown in FIGS. 1 and 2, a vehicle headlamp 10 according to an embodiment of the present invention has a lamp unit 5 housed in a lamp chamber 4 defined by a lamp body 2 and a translucent cover 3. This is a projector-type headlight. The lamp unit 5 has an optical axis Ax extending in the vehicle front-rear direction, and is supported by the lamp body 2 via an aiming mechanism (not shown) so as to be tiltable in the vertical direction and the horizontal direction. An extension 6 is provided in the lamp chamber 4 along the translucent cover 3.

  The lamp unit 5 includes a projection lens 14 arranged on the optical axis Ax, a light source bulb 11 arranged behind the rear focal point F of the projection lens, and light from the light source bulb directed forward. A reflector 12 that reflects toward the axis Ax, a lens holder 7 that positions and holds the projection lens 14 with respect to the reflector, and a shade 13 that is an optical control member are provided.

  The light source bulb 11 is a white discharge bulb and is assembled in the rear top opening of the reflector 12. The reflector 12 is formed in a substantially spheroidal shape having the light source bulb 11 as a first focus and the rear focus of the projection lens 14 as a second focus. The light from the light source bulb 11 is directed forward. It has a reflecting surface that reflects toward the optical axis Ax.

  The shade 13 is a light shielding plate, and is fixedly supported by the lens holder 7 so that the upper end edge thereof is disposed on the optical axis Ax. The shade 13 is disposed between the light source bulb 11 and the projection lens 14 so that the upper edge thereof passes through the rear focal point F of the projection lens 14. Then, a part of the reflected light heading forward and upward from the reflector 12 is blocked to form a light distribution pattern cut line.

  The projection lens 14 is configured as a plano-convex lens having a convex surface on the front surface and a flat surface on the rear surface, and projects an image on the focal plane including the rear focus F forward as a reverse image. ing. The convex curved surface on the front surface is composed of an aspheric surface formed so that the rear focal point F of the projection lens 14 is positioned on the optical axis Ax. In the projection lens 14, a first projection lens member 15 disposed at the upper portion and a second projection lens member 16 disposed at the lower portion are integrally formed.

  The first projection lens member 15 is formed of a transparent resin material as a raw material, and is formed into a half-divided shape in a horizontal plane passing through the optical axis, and has a refractive index larger than that of the second projection lens member 16. ing.

  The second projection lens member 16 is formed in the same way as the first projection lens member 15 by using a transparent resin material as a material and dividing the hemispherical shape into two equal parts on a horizontal plane passing through the optical axis. A refractive index smaller than that of the lens member 15 is set.

  For example, the first projection lens member 15 is made of polycarbonate (n = 1.58), and the second projection lens member 16 is made of acrylic (n = 1.49). Alternatively, the first projection lens member 15 can be formed of acrylic (n = 1.49), and the second projection lens member 16 can be formed of silicon-based resin (n = 1.41). Further, the first projection lens member 15 may include nanoparticles to increase the refractive index.

  In the vehicle headlamp 10, the light from the light source bulb 11 is reflected toward the front of the optical axis Ax by the reflector 12, and a part of the reflected light from the reflector 12 is blocked by the shade 13. By forming a cut line, a light / dark break is set. Then, the light is incident on an incident surface 17 that is a refracting portion of the first projection lens member 15 and an incident surface 18 that is a refracting portion of the second projection lens member 16.

At this time, the light that has traveled upward among the light incident on the projection lens 14 is converted into red light α1, yellow-green light α2, and blue light α3 by the first projection lens member 15 for the first time. The light is emitted from an emission surface 19 that is a refracting portion of the projection lens member 15. At this time, the blue light α3 is refracted the most and the red light α1 is refracted the smallest. The red light α1 is refracted so as to be substantially parallel to the optical axis, but this is adjusted by the refractive index of the first projection lens member 15.
On the other hand, the light traveling downward is emitted from the emission surface 20 of the second projection lens member 16 by the second projection lens member 16 as red light β1, yellow-green light β2, and blue light β3. . At this time, the blue light β3 is refracted the most and the red light β1 is refracted the smallest. The blue light β3 is refracted so as to be substantially parallel to the optical axis, but this is adjusted by the refractive index of the second projection lens member 16. That is, the refractive index of the first projection lens member 15 is larger than the refractive index of the second projection lens member 16, and the red light α 1 refracted by the first projection lens member 15 and the blue light refracted by the second projection lens member 16. β3 is irradiated in the same direction as substantially parallel light. Similarly, the blue light α3 refracted by the first projection lens member 15 and the red light β1 refracted by the second projection lens member 16 are irradiated in the same direction as downward light.

  The red light α1 and the blue light β3 emitted substantially horizontally out of the light split through the projection lens are mixed with the white light below the cut line of the light distribution pattern. The color stripes of the light α1 and the blue light β3 are not noticeable. Further, since the red light α1 and the blue light β3, and the red light β1 and the blue light α3 in the light distribution pattern are mixed, the light becomes substantially white light, and the red and blue are hardly noticeable.

  As described above, according to the vehicle headlamp 10 of the first embodiment, the light from the light source bulb 11 is reflected forward by the reflector 12 toward the optical axis Ax, and is reflected from the reflector 12 by the shade 13. A part of the reflected light is blocked to form a light distribution pattern and is incident on the projection lens 14. Of the light incident on the projection lens 14, the upper light is refracted downward and mixed with the white light below the cut line, and the red light α1, β1 and the blue light α3, β3 of the pattern are mixed. Can be mixed into white light, and red light and blue light can be made almost inconspicuous. Thereby, since it is not necessary to process the projection lens 14 into a complicated shape, the vehicle headlamp 10 including the projection lens 14 that is excellent in processability and does not cause chromatic aberration can be obtained.

  Further, according to the vehicle headlamp 10, the projection lens 14 includes the first projection lens member 15 and the second projection lens member 16 having different refractive indexes on the light incident surfaces 17 and 18 and the light exit surfaces 19 and 20. By having them, both the projection lens members 15 and 16 can be mechanically integrated integrally, or can be easily manufactured by existing molding equipment that has been used conventionally.

(Second Embodiment)
Next, a vehicle headlamp according to the second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic view showing a projection lens according to the second embodiment of the present invention. In the following embodiments, components that are the same as those in the first embodiment described above or functionally similar components are simplified or omitted by giving the same reference numerals or equivalent symbols in the drawings. To do.

  As shown in FIG. 3, the vehicle headlamp 30 according to the second embodiment of the present invention uses an LED (Light Emitting Diode) as a light source 31, and is an optical control member having a reflection function. A light source 31 is mounted on a certain shade 32. The LED generates less heat than the discharge bulb used in the first embodiment. Therefore, it is suitable when using a projection lens made of a resin that is less durable than glass. The projection lens 14 is formed by integrally forming a first projection lens member 15 and a second projection lens member 16.

  In the vehicle headlamp 30, the light of the LED 31 that is a light source is reflected forward by the reflector 12 toward the optical axis, and a part of the reflected light that is directed forward and downward from the reflector 12 is directed forward and upward by the shade 32. The light and dark breaks are set by forming the cut line of the light distribution pattern by reflecting the light. Then, the light enters the incident surface 17 of the first projection lens member 15 and the incident surface 18 of the second projection lens member 16.

At this time, the light that has traveled upward among the light incident on the projection lens 14 is converted into red light α1, yellow-green light α2, and blue light α3 by the first projection lens member 15 for the first time. The light is emitted from an emission surface 19 that is a refractive portion of the projection lens member 15. At this time, the blue light α3 is refracted the most and the red light α1 is refracted the smallest. The red light α1 is refracted so as to be substantially parallel to the optical axis, but this is adjusted by the refractive index of the first projection lens member 15.
On the other hand, the light traveling downward is emitted from the emission surface 20 of the second projection lens member 16 by the second projection lens member 16 as red light β1, yellow-green light β2, and blue light β3. . At this time, the blue light β3 is refracted the most and the red light β1 is refracted the smallest. The blue light β3 is refracted so as to be substantially parallel to the optical axis, but this is adjusted by the refractive index of the second projection lens member 16. That is, the refractive index of the first projection lens member 15 is larger than the refractive index of the second projection lens member 16, and the red light α 1 refracted by the first projection lens member 15 and the blue light refracted by the second projection lens member 16. β3 is irradiated in the same direction as substantially parallel light. Similarly, the blue light α3 refracted by the first projection lens member 15 and the red light β1 refracted by the second projection lens member 16 are irradiated in the same direction as downward light.

  The red light α1 and the blue light β3 emitted substantially horizontally out of the light split through the projection lens are mixed with the white light below the cut line of the light distribution pattern. The color stripes of the light α1 and the blue light β3 are not noticeable. Further, since the red light α1 and the blue light β3, and the red light β1 and the blue light α3 in the light distribution pattern are mixed, the light becomes substantially white light, and the red and blue are hardly noticeable.

  Since the vehicular headlamp 30 according to the second embodiment has the same functions and effects as those of the first embodiment described above, the description thereof is omitted. In particular, according to the present embodiment, the shade 32 is A part of the reflected light directed downward from the reflector 12 is reflected upward and upward to form a light distribution pattern cut line, so that when the light / dark separation is set, the light incident on the projection lens 14 is reflected. Among them, the upper light is refracted downward and mixed with the white light below the cut line, and the red light α1, β1 and the blue light α3, β3 of the light distribution pattern are mixed to become white light, Red light and blue light can be made inconspicuous.

(Third embodiment)
Next, a vehicle headlamp according to a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a schematic view showing a projection lens according to the third embodiment of the present invention.

  As shown in FIG. 4, the vehicle headlamp 40 according to the third embodiment of the present invention includes a central projection lens member 42 disposed around the optical axis and an upper portion disposed above the central projection lens member 42. A projection lens 41 having a three-piece integral structure having a projection lens member 43 and a lower projection lens member 44 disposed below the central projection lens member 42 is provided.

  The projection lens 41 is set such that the refractive index of the upper projection lens member 43 is larger than the refractive index of the central projection lens member 42 and the refractive index of the lower projection lens member 44 is smaller than the refractive index of the central projection lens member 42. ing.

  In the vehicle headlamp 40, the light of the LED 31 is reflected toward the front by the reflector 12 toward the optical axis, and the shade 32 reflects a part of the reflected light from the reflector 12 toward the front lower side toward the front upper side. Thus, the light / dark separation is set by forming the cut line of the light distribution pattern. Then, the light enters the incident surface 45 of the upper projection lens member 42, the incident surface 46 of the central projection lens member 42, and the incident surface 47 of the lower projection lens member 44.

At this time, the light that has traveled upward of the light incident on the projection lens 41 is converted into red light α1, yellow-green light α2, and blue light α3 by the upper projection lens member 43, and the upper projection lens member. The light is emitted from an exit surface 48 which is a refractive part 43. At this time, the blue light α3 is refracted the most and the red light α1 is refracted the smallest. The red light α1 is refracted so as to be substantially parallel to the optical axis, but this is adjusted by the refractive index of the upper projection lens member 43.
On the other hand, the light traveling downward is emitted from the emission surface 50 of the lower projection lens member 44 by the lower projection lens member 44 as red light β1, yellow-green light β2, and blue light β3. At this time, the blue light β3 is refracted the most and the red light β1 is refracted the smallest. The blue light β3 is refracted so as to be substantially parallel to the optical axis, but this is adjusted by the refractive index of the lower projection lens member 44. That is, the refractive index of the upper projection lens member 43 is made larger than the refractive index of the lower projection lens member 44, and the red light α1 refracted by the upper projection lens member 43 and the blue light β3 refracted by the lower projection lens member 44 are substantially parallel. The light is irradiated in the same direction. Similarly, the blue light α3 refracted by the upper projection lens member 43 and the red light β1 refracted by the lower projection lens member 44 are irradiated in the same direction as downward light.

  The red light α1 and the blue light β3 emitted substantially horizontally out of the light split through the projection lens are mixed with the white light below the cut line of the light distribution pattern. The color stripes of the light α1 and the blue light β3 are not noticeable. Further, since the red light α1 and the blue light β3, and the red light β1 and the blue light α3 in the light distribution pattern are mixed, the light becomes substantially white light, and the red and blue are hardly noticeable.

  Since the vehicle headlamp 40 of the third embodiment has the same operational effects as those of the first embodiment described above, description thereof is omitted.

(First modification)
Next, with reference to FIG. 5, a first modification of the above-described third embodiment will be described. FIG. 5 is a longitudinal sectional view of a first modification of the vehicle headlamp according to the present invention.

  As shown in FIG. 5, in the first modification example of the present invention, the central projection lens 42 of the projection lens 41 includes extending portions 51 and 52 connected to the upper front surface and the lower front surface, respectively.

  In this modification, the light that has traveled upward among the light incident on the projection lens 41 enters the extension portion 51 and then enters the upper projection lens member 43, whereby the red light α1 is converted into the optical axis Ax. The light that is refracted so as to be substantially parallel to the light and travels downward is incident on the extension portion 52 and then on the lower projection lens member 44, so that the blue light β3 becomes substantially parallel to the optical axis Ax. Will be refracted.

(Second modification)
Next, a second modification of the above-described third embodiment will be described with reference to FIG. FIG. 6 is a longitudinal sectional view of a second modification of the vehicle headlamp according to the present invention.

  As shown in FIG. 6, in the second modification of the present invention, the upper projection lens 43 of the projection lens 41 has an extending part 53 connected to the upper rear surface, and the lower projection lens 44 of the projection lens 41 is lower rear surface. It has the extension part 54 connected to.

  In the present modification, the light traveling upward from the light incident on the projection lens 41 is incident on the upper projection lens 43 and refracted so that the red light α1 is substantially parallel to the optical axis Ax. The light emitted through the extending portion 53 and traveling downward is incident on the lower projection lens 44, refracted so that the blue light β3 is substantially parallel to the optical axis Ax, and is emitted through the extending portion 54. become.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved. For example, the structure which combined the 1st modification mentioned above and the 2nd modification is also possible. That is, a synergistic effect can be obtained by providing the extending portions 51 and 52 (see FIG. 5) in the vertical direction from the central projection lens 42 of the second modified example. In addition, it is possible to improve the assembling property by forming the coupling portion of the lens in a tapered shape.

1 is a longitudinal sectional view of a vehicle headlamp according to the present invention. It is the schematic of the projection lens which concerns on 1st Embodiment of this invention. It is the schematic of the projection lens which concerns on 2nd Embodiment of this invention. It is the schematic of the projection lens which concerns on 3rd Embodiment of this invention. It is the schematic of the projection lens which shows the 1st modification of 3rd Embodiment which concerns on this invention. It is the schematic of the projection lens which shows the 2nd modification of 3rd Embodiment which concerns on this invention.

Explanation of symbols

10, 30, 40 Vehicle headlamp 11, 31 Light source bulb (light source)
12 reflector 13, 32 shade (optical control member)
14, 41 Projection lens 15 First projection lens member (lens member)
16 Second projection lens member (lens member)
17, 18 Incident surface (refractive part)
19, 20 Output surface (refractive part)
31 LED (light source)
42 Central projection lens member (lens member)
43 Upper projection lens member (lens member)
44 Lower projection lens member (lens member)
45, 46, 47 Incident surface (refractive part)
48, 49, 50 Output surface (refractive part)

Claims (4)

A light source;
A projection lens arranged on an optical axis extending in the vehicle longitudinal direction;
A reflector that reflects light from the light source forward and closer to the optical axis;
An optical control member disposed between the projection lens and the light source to block or reflect part of the reflected light from the reflector to form a light distribution pattern;
A vehicle headlamp comprising:
The projection lens includes a refracting portion made of a plurality of materials that refracts and emits light incident upward from the incident light that is larger than the light incident downward. Vehicle headlamp.   The vehicular headlamp according to claim 1, wherein the projection lens includes a plurality of lens members having different refractive indexes above and below a light exit surface or an incident surface. The optical control member forms a cut line of the light distribution pattern by blocking a part of reflected light toward the rear focal point of the projection lens and the rear thereof from the reflector.
3. The vehicular headlamp according to claim 1, wherein the projection lens includes at least two types of lens members having different refractive indexes so that the refractive index is higher on the upper side than on the lower side. The optical control member reflects, from the reflector, a rear focal point of the projection lens and a part of reflected light toward the rear toward the front upper side to form a cut line of the light distribution pattern,
3. The vehicular headlamp according to claim 1, wherein the projection lens includes at least two types of lens members having different refractive indexes so that the refractive index is higher on the upper side than on the lower side.

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