JP4863502B2 - Vehicle headlamp - Google Patents

Description

  The present invention relates to a projector-type vehicle headlamp that uses, as a light source, an LED that is used, for example, as a headlamp or an auxiliary headlamp provided at the front of an automobile.

Conventionally, such a vehicle headlamp is configured as shown in FIG.
That is, in FIG. 5, the vehicle headlamp 1 includes an LED light source 2, a reflector 3, a projection lens 4, and a light shielding member 5.

The LED light source 2 includes a flat substrate 2a and an upper surface (or an LED 2b mounted on the upper and lower surfaces) of the substrate 2a.
The LED light source 2 has a substrate 2a that is disposed almost horizontally forward along the optical axis O, and is supplied with power from the outside.

The reflector 3 is composed of an elliptical reflecting surface arranged so that the inner surface of the reflector 3 is positioned near the light emission center of the LED light source 2 and the long axis extends substantially horizontally toward the front. This inner surface is formed as a reflecting surface.
Here, the elliptical reflecting surface includes not only a spheroid and an elliptic cylinder but also a free-form surface based on an ellipsoid.

  The projection lens 4 is composed of a convex lens, preferably an aspheric lens, and the focal point on the light source side (rear side) is disposed in the vicinity of the second focal position F2 of the reflector 3, and the LED light source 2 Alternatively, the light traveling forward from the reflector 3 is collected and irradiated forward.

  The light shielding member 5 is for giving a predetermined light distribution pattern for a low beam to the light irradiated toward the front, and is disposed in the vicinity of the second focal position F2 of the reflector 3. Yes. Moreover, in order to form a cut-off line in the light distribution pattern, the upper edge 5a is formed in a predetermined shape.

According to the vehicle headlamp 1 having such a configuration, when the LED light source 2 is fed and emits light, the light emitted from the LED light source 2 is reflected directly or by the reflector 3, and the reflector 3. The light travels forward toward the vicinity of the second focal point, and is irradiated forward while being focused by the projection lens 4.
At that time, a part of the light irradiated forward is blocked by the light blocking member 5, and a cut-off line is formed by the upper edge 5 a of the light blocking member 5, and is irradiated forward as a passing beam. It will be.

  As a result, as shown in FIG. 6, the upper edge 5 a of the light shielding member 5 is projected by the projection lens 4. For this reason, with respect to the light distribution pattern, a cut-off line C is formed which extends horizontally from the center to the right slightly below the horizontal line and horizontally from the center to the left side substantially along the horizontal line. On the other hand, light suitable for the low beam is emitted.

In this way, in such a vehicle headlamp 1, in the case of a passing beam, a cut-off line C is formed by the light-shielding member 5, and as shown in FIG. An optical pattern A is formed.
By irradiating the upper edge 5a of the light shielding member 5 forward in the light irradiation direction, no light is irradiated on the upper side of the cut-off line C, so that no dazzling light is given to the oncoming vehicle.

However, in the vehicle headlamp 1 having such a configuration, the straight line connecting the first focal point and the second focal point of the reflector 3 substantially coincides with the optical axis of the projection lens 4. For this reason, in the optical system based on the combination of the reflector 3 and the projection lens 4, the so-called depth dimension of the optical unit from the rear end of the reflector 3 to the front end of the projection lens 4 is the interfocal distance of the reflector, the focal length of the reflector, and the projection. This is the sum of the focal lengths of the lenses 4 and is uniquely determined.
Therefore, when the basic focal length of the optical system is determined, the depth dimension of the lamp of the vehicle headlamp is inevitably determined, and it is not possible to meet the demand for reducing the lamp depth in the recent vehicle design. It will be difficult to reduce the thickness of the lighting.

Further, each LED of the LED light source has a so-called Lambertian emission distribution, and the light near the central axis with the highest luminance is reflected by the reflector 3 and is not near the center of the projection lens 4 but the projection lens 4. In this case, the projection lens 4 protrudes from the periphery.
For example, the light source image of the LED 2b mounted on the upper surface of the substrate 2a of the LED light source 2 protrudes from the periphery of the projection lens 4 in the lower region of the projection lens 4 as indicated by reference numeral L1 in FIG. Will be formed.
Therefore, a part of the light emitted from the LED 2b of the LED light source 2, particularly a portion with high luminance, is vignetted at the periphery of the projection lens 4 and is not irradiated forward. For this reason, the utilization efficiency of the light from the LED light source 2 decreases, the luminance of the light distribution pattern decreases, the light condensing property decreases, the luminance near the center of the light distribution pattern also decreases, and the far vision There was also a lack of sex.

Further, since a clear cut-off line C is formed by the light shielding member 5, a light distribution pattern for a so-called overhead sign such as a road sign installed on the road is not formed.
For this reason, in the vehicle headlamp 1 described above, in order to cope with such light distribution for overhead sign, the light shielding member 5 is used for overhead sign at a position away from the focal position (F2) of the projection lens 4. It is conceivable to provide a window for light distribution.

Thereby, a part of the light emitted from the LED light source 2 is reflected by the lower region 3 a of the reflector 3 and passes through the window portion of the light shielding member 5, so that the front horizontal line passes through the projection lens 4. Irradiated slightly upward, light distribution for overhead sign can be formed.
In this case, since the window portion is out of the focus of the projection lens 4, the overhead sign light distribution is projected in a slightly blurred state, and the light and dark boundary lines around this light distribution are anxious. There is nothing.
Further, since the light reflected by the lower region 3a of the reflector 3 that does not form the passing beam light distribution pattern is used, the passing beam light distribution pattern does not become dark.

However, when a window for forming the overhead sign light distribution is formed below the upper edge 5a of the light shielding member 5, there is a structure between the window and the upper edge 5a of the light shielding member 5. From the above point, certain dimensions are required.
Therefore, it is impossible to set the overhead sign light distribution pattern so as to be in contact with the upper end of the low beam light distribution pattern.

Further, the light reflected by the reflector 3 for forming the light distribution for the passing beam is passed through the window portion of the light shielding member 5 and the shape of this window portion is projected onto the overhead sign region by the projection lens 4. ing.
Therefore, the light distribution for overhead sign is formed by the light condensed by the projection lens 4, and the light distribution characteristic is not necessarily optimum as the light distribution for overhead sign.

  In view of the above, the present invention has a simple configuration in which the depth dimension of the lamp is reduced, the directional characteristics of the LED light source can be effectively used, and the overhead sign light distribution can be formed. The purpose is to provide lighting.

According to the present invention, the first object is to provide an LED light source comprising at least one LED mounted substantially vertically on a substrate and to reflect light from the LED light source forward in the light irradiation direction. A concave elliptical reflective surface forwardly in the light irradiation direction arranged so that the focal position of the light source is located near the light emitting portion of the light source and the second focal position is located in front of the light irradiation direction, and the reflection surface And a convex projection lens arranged so that the focal position on the light source side is positioned in the vicinity of the second focal position of the reflecting surface on the substantially horizontal optical axis. In the vehicle headlamp, the long axis is arranged to be inclined downward toward the rear so that the first focal position of the reflecting surface is located rearward and lower than the second focal position, A perpendicular line extending perpendicularly to the substrate from the light emission center of the LED light source And extension of the optical axis of the projection lens, and wherein the crossing on the reflecting surface, the vehicle headlamp is achieved.

  In the vehicle headlamp according to the present invention, the distance between the first focal point and the second focal point of the reflecting surface is preferably selected to be shorter than the focal length of the projection lens.

  The vehicle headlamp according to the present invention preferably further includes a heat radiating member disposed at a position away from the LED light source, and the heat radiating member is heated via the substrate of the LED light source and the heat conducting member. Connected.

  The vehicle headlamp according to the present invention preferably further includes a light-shielding member that is disposed in the vicinity of the second focal position of the reflecting surface and has an upper edge that defines a cut-off line.

  In the vehicle headlamp according to the present invention, preferably, the light shielding member has a window portion for light distribution for overhead sign that transmits direct light from the LED light source toward the upper front in the light irradiation direction. Yes.

According to the above configuration, the light incident on the reflecting surface from the LED light source is reflected by the reflecting surface, converged toward the second focal position, and further converged by the projection lens, and forward in the light irradiation direction. Irradiated towards.
Thereby, the light source image of the LED light source is projected forward by the projection lens in the light irradiation direction, and a predetermined light distribution pattern is formed.

Here, the central axis (long axis) connecting the two focal points of the reflecting surface is inclined downward toward the rear. As a result, the depth dimension in the front-rear direction of the optical unit and the lamp of the vehicle headlamp is shortened, and the vehicle headlamp can be configured to be thin.
Thereby, it becomes possible to cope with the lamp depth reduction in recent vehicle designs.

  Further, since the substrate of the LED light source is also inclined downward toward the rear, among the light from the individual LEDs mounted vertically on the substrate of the LED light source, the so-called luminance of the so-called Lambertian emission distribution is the highest. Light in a direction perpendicular to the high substrate is reflected by the reflecting surface and enters the vicinity of the center of the projection lens. For this reason, there is no vignetting at the periphery of the projection lens, the use efficiency of light from the LED light source is improved, and a brighter light distribution pattern is obtained.

  When the distance between the first focal point and the second focal point of the reflecting surface is selected to be shorter than the focal length of the projection lens, the depth dimension of the optical unit of the vehicle headlamp and the lamp is shorter. As a result, the vehicle headlamp can be made thinner.

When the perpendicular extending perpendicularly to the substrate from the light emission center of the LED light source intersects with the extension line of the optical axis of the projection lens on the reflection surface, the substrate vertical with the highest light emission luminance of the LED of the LED light source The light emitted in the direction enters the extension line of the optical axis of the projection lens on the reflection surface and is reflected forward in the light irradiation direction along the optical axis of the projection lens.
Accordingly, the brightest part of the light from the LED light source is incident near the center of the projection lens, so that vignetting due to the periphery of the projection lens is greatly reduced and higher near the center. An ideal light distribution pattern with brightness can be obtained.

  Furthermore, when the heat radiating member arrange | positioned in the position away from the said LED light source is provided, and this heat radiating member is thermally connected via the board | substrate of the said LED light source via a heat conductive member, said LED Since the substrate of the light source is disposed at an inclination, it is difficult to secure the location of the heat dissipation member for heat dissipation of the substrate. However, if the position is away from the LED light source, the heat dissipation member can be easily disposed. It becomes possible to do. In addition, heat generated in the LED is transmitted from the substrate to the heat radiating member via the heat conducting member, and is radiated from the heat radiating member to the outside, so that the LED light source can be radiated reliably.

  Further, in the case of including a light shielding member that is disposed near the second focal position of the reflecting surface and whose upper edge defines a cut-off line, a part of the light reflected by the reflecting surface is The light distribution pattern for the low beam is formed by being cut off by the light shielding member and forming a cut-off line by the upper edge thereof.

When the light shielding member has a window for light distribution for overhead sign that transmits the direct light from the LED light source toward the upper front in the light irradiation direction, the light emitted from the LED light source Part of the light is directly incident on the window, and is further directed to the upper side in front of the light irradiation direction through the projection lens, that is, the light distribution area for overhead sign slightly above the horizontal line in front of the light irradiation direction. Is done.
As a result, an overhead sign light distribution is formed. For example, by irradiating a road sign or the like located slightly above the horizon with respect to the traveling direction of the automobile, these road signs and the like are illuminated brightly. A sign etc. can be visually recognized reliably.

In this case, light that does not contribute to the formation of the light distribution pattern for the low beam is incident on the window for forming the light distribution for the overhead sign. For this reason, the light beam forming the passing beam light distribution pattern is not reduced, and the light utilization efficiency is improved.
Further, the overhead sign light distribution is not reflected by the reflecting surface, but directly enters the projection lens through the window. For this reason, a light distribution characteristic different from that of the passing beam due to the shape of the reflecting surface is given, and an optimal overhead sign light distribution is obtained, and the overhead sign visibility is improved.
Further, the overhead sign light distribution is formed by the window portion of the light shielding member. For this reason, compared with the conventional vehicle headlamp, no additional parts are required, so that it can be configured at a low cost with a simple configuration.

  In this way, according to the present invention, with a simple configuration, the depth dimension of the lamp can be reduced, the directivity performance of the LED light source can be used effectively, and a light distribution for overhead sign can be formed. A vehicle headlamp could be provided.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS.
The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. As long as there is no description of the effect, it is not restricted to these aspects.

[Example 1]
FIG. 1 shows the configuration of a first embodiment of a vehicle headlamp according to the present invention.
In FIG. 1, a vehicle headlamp 10 is configured as an automobile headlamp, and includes an LED light source 11, a reflector 12 that reflects light from the LED light source 11 forward in the light irradiation direction, and an LED light source 11. Alternatively, the projection lens 13 is configured to focus light traveling forward from the reflector 12, and the light shielding member 14 is disposed in the optical path from the LED light source 11 to the projection lens 13.

The LED light source 11 is an LED light source generally used for automobile headlamps or auxiliary headlamps, and is supplied with power from the outside.
Here, in the LED light source 11, at least one LED 11b is mounted on a flat substrate 11a, and the central axis of each LED 11b is arranged substantially perpendicular to the substrate 11a.

The inner surface of the reflector 12 is formed in a concave shape so as to reflect the light from the LED light source 11 forward, and the first focal position F1 is the light emission center of the LED light source 11. It is configured as an elliptical reflecting surface arranged so as to be located in the vicinity.
Here, the elliptical reflecting surface includes not only a spheroid and an elliptic cylinder but also a free-form surface based on an ellipsoid.
The reflector 12 is formed substantially so as to give a light distribution pattern for passing beams.

  The projection lens 13 is composed of, for example, an aspherical convex lens, and the optical axis is substantially horizontal toward the front in the light irradiation direction so that the focal position on the light source side is located near the second focal position F2 of the reflector 12. It is arranged on O.

The light shielding member 14 is made of a light shielding material, and is disposed near the second focal position F2 of the reflector 12, that is, near the focal position on the light source side of the projection lens 13.
Accordingly, the upper edge 14a of the light shielding member 14 is projected forward by the projection lens 13 in the light irradiation direction, so that a cut-off line in the light distribution pattern for the passing beam is formed.

The above configuration is substantially the same as the conventional vehicle headlamp 1 shown in FIG. 5, but the vehicle headlamp 10 according to the embodiment of the present invention is configured differently in the following points.
That is, as shown in FIG. 1, the reflector 12 has a central axis (long axis) passing through the first focal point F1 and the second focal point F2 inclined downward toward the rear.
Further, the reflector 12 is selected such that the interfocal distance d1a between the first focal point F1 and the second focal point F2 is shorter than the focal length d2 of the projection lens 13.
The LED light source 11 is arranged such that the surface of the substrate 11a extends along the central axis of the reflector 12 so as to be inclined downward toward the rear.

In the case shown in the figure, the inclination angle of the LED light source 11 and the reflector 12 is, for example, 45 degrees, and the distance (d1) from the second focal point F2 of the reflector 12 to the rear end is required to be about 20 mm.
On the other hand, the horizontal distance d1 ′ is calculated as a cosine (d1 ′ = d1 × cos θ) with respect to the inclination angle θ by the above-described inclination arrangement, so that it is about 14.1 mm, and the depth reduction is about 30%. An effect will be obtained.

  Further, in the illustrated case, a perpendicular extending perpendicularly to the substrate 11 a from the LED 11 b of the LED light source 11 intersects the optical axis O of the projection lens 13 at the vicinity P of the inner surface of the reflector 12.

The vehicle headlamp 10 according to the embodiment of the present invention is configured as described above, and light is emitted from the LED 11b of the LED light source 11 when the LED light source 11 is supplied with power from the outside and emits light.
The light L1 emitted from the LED light source 11 is reflected by the reflector 12, converged toward the vicinity of the second focal position F2, and further converged via the projection lens 13 while being irradiated forward in the light irradiation direction. Is done.
At this time, a cut-off is formed by the upper edge 14a of the light shielding member 14, whereby a light distribution pattern B1 for a low beam is formed as shown in FIG.

In this case, even if the LED light source 11 and the reflector 12 are inclined downward and rearward with respect to the optical axis O of the projection lens 13, even an optical system having the same optical characteristics can be used. The direction of the optical axis O is shortened by the amount of inclination.
Furthermore, since the distance d1 from the second focal point F2 to the rear end of the reflector 12 is selected to be shorter than the focal length of the projection lens 13, the entire vehicle headlamp 10 is made thinner in the front-rear direction. Will get.

Further, the light in the central axis direction that gives the maximum luminance of the Lambertian emission distribution of the LED 11 b of the LED light source 11 is reflected by the reflector 12 and enters the projection lens 13 along the optical axis O.
As a result, the light L2 from the LED light source 11 enters the vicinity of the center of the projection lens 13, as shown in FIG. For this reason, vignetting due to the periphery of the projection lens 13 in the brightest part of the light from the LED light source 11 is greatly reduced, and an ideal light distribution pattern having higher brightness near the center. Will be obtained.
Therefore, higher luminance is obtained near the center of the light distribution pattern, and far visibility is improved.

[Example 2]
FIG. 3 shows a configuration of a second embodiment of the vehicle headlamp according to the present invention.
In FIG. 3, the vehicle headlamp 20 has substantially the same configuration as the vehicle headlamp 10 shown in FIG. 1, and thus the same components are denoted by the same reference numerals and description thereof is omitted.
The vehicle headlamp 20 is different from the vehicle headlamp 10 of FIG. 1 in that a heat pipe 21 is thermally connected to the back side of the substrate 11 a of the LED light source 11.

The heat pipe 21 is thermally connected to a heat radiating member 22 arranged at a position away from the LED light source 11.
Thus, heat generated by driving the LED 11b of the LED light source 11 is transmitted from the substrate 11a to the heat radiating member 22 through the heat pipe 21, and is radiated from the heat radiating member 22 to the outside.

According to the vehicle headlamp 20 having such a configuration, it acts in the same manner as the vehicle headlamp 10 shown in FIG. 1 and reliably radiates heat from the LED light source 11 through the heat pipe 21 by the heat radiating member 22. It will be. For this reason, each LED11b of the said LED light source 11 can be thermally radiated efficiently, and luminous efficiency does not fall by temperature rise.
Furthermore, even if the arrangement location of the heat radiation member for heat radiation of the substrate 11a cannot be ensured by the arrangement inclined downward toward the rear of the LED light source 11, the heat radiation member 22 arranged at a distant position surely radiates heat. Can be done.

[Example 3]
FIG. 4 shows the configuration of the third embodiment of the vehicle headlamp according to the present invention.
In FIG. 4, the vehicle headlamp 30 has substantially the same configuration as the vehicle headlamp 10 shown in FIG. 1, and therefore the same components are denoted by the same reference numerals and description thereof is omitted.
The vehicle headlamp 30 is different from the vehicle headlamp 10 of FIG. 1 in that a window 14b is provided slightly below the upper edge 14a of the light shielding member 14. In this embodiment, the LED light source 11 is inclined downward toward the rear at a larger inclination angle than the LED light source 11 in the vehicle headlamp 10 of FIG.

The window portion 14b transmits direct light from the LED 11b of the LED light source 11.
The size and position of the window portion 14b are selected so that the transmitted light is irradiated through the projection lens 13 toward the upper overhead sign region in front of the light irradiation direction.

According to the vehicle headlamp 30 having such a configuration, the vehicle headlamp 10 operates in the same manner as the vehicle headlamp 10 shown in FIG. 1, and the overhead sign distribution is provided through the window portion 14b provided in the light shielding member 14. Light is applied to, for example, a road sign located slightly above the horizon with respect to the traveling direction of the automobile. For this reason, these road signs etc. are illuminated brightly, and these road signs etc. can be visually recognized reliably.
In this case, the overhead sign light distribution uses direct light from the LED light source 11 that does not contribute to the formation of the passing beam light distribution pattern. Thereby, the light beam forming the light distribution pattern B1 of the low beam is not reduced by the installation of the window portion 14b.

Further, the outline of the window portion 14b determines the shape of the periphery of the overhead sign light distribution pattern B2. For this reason, by appropriately selecting the size and shape of the window portion 14b, the size and shape of the overhead sign light distribution pattern B2 can be adjusted without depending on the reflection characteristics of the reflector 12. .
Therefore, the overhead sign light distribution can be formed to satisfy a predetermined light distribution standard.

  In the above-described embodiment, the light distribution pattern for the passing beam is formed by providing the light shielding member 14, but the present invention is not limited to this, and the light shielding member 14 is omitted, so It is obvious that the light distribution pattern may be formed.

  Moreover, in 2nd embodiment mentioned above, although the heat pipe 21 is provided in the board | substrate 11a of the said LED light source 11, not only this but heat is provided with respect to the heat radiating member 22 arrange | positioned in the distant position. As long as it can conduct, you may make it provide another heat conductive member.

  Furthermore, in the above-described embodiment, the case where the vehicle headlamp 10 is a headlamp has been described. However, the present invention is not limited to this, and other types of vehicle headlamps, for example, auxiliary headlamps such as bending lamps and fog lamps are used. It can also be configured as a lamp.

  As described above, according to the present invention, the depth dimension of the lamp can be reduced with a simple configuration, the directivity performance of the LED light source can be effectively used, and the overhead sign light distribution can be formed. An extremely excellent vehicle headlamp can be provided.

1 is a schematic side view showing a configuration of a first embodiment of a vehicle headlamp according to the present invention. It is a schematic front view which shows the incident light to the projection lens in the vehicle headlamp of FIG. It is a schematic side view which shows the structure of 2nd embodiment of the vehicle headlamp by this invention. It is a schematic side view which shows the structure of 3rd embodiment of the vehicle headlamp by this invention. It is a schematic side view which shows the structure of an example of the conventional vehicle headlamp. It is a graph which shows the light distribution pattern for passing beams by the vehicle headlamp of FIG. It is a schematic front view which shows the incident light to the projection lens in the vehicle headlamp of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle headlamp 11 LED light source 12 Reflector 13 Projection lens 14 Light-shielding member 14a Upper edge 14b Window part

Claims (5)

An LED light source composed of at least one LED mounted substantially vertically on the substrate, and the first focal position is near the light emitting portion of the light source so as to reflect light from the LED light source forward in the light irradiation direction. And an elliptical reflecting surface that is concave toward the front in the light irradiation direction and is disposed so that the second focal position is located in front of the light irradiation direction, and a substantially horizontal optical axis in front of the reflection surface. In the vehicular headlamp, the reflecting surface includes a convex projection lens disposed so that the focal position on the light source side is positioned near the second focal position of the reflecting surface. The long axis of the LED light source is inclined downward and rearward so that the first focal position is located rearward and lower than the second focal position, and is perpendicular to the substrate from the light emission center of the LED light source. The vertical line extending to the extension of the optical axis of the projection lens When, the vehicle headlamp, characterized in that cross on the reflecting surface. The vehicle headlamp according to claim 1, wherein a distance between the first focal point and the second focal point of the reflecting surface is selected to be shorter than a focal length of the projection lens. And a heat dissipating member disposed at a position distant from the LED light source, wherein the heat dissipating member is thermally connected to the substrate of the LED light source via a heat conducting member. vehicle headlamp according to any one of claims 1 to 2. Furthermore, arranged near the second focal point of the reflecting surface, the upper edge, characterized in that it comprises a light blocking member formed to define a cut-off line, any one of claims 1 to 3 Vehicle headlamp as described in The light shielding member, characterized in that it includes a window portion for overhead sign light distribution which transmits direct light from the LED light source toward the upper side of the light irradiation direction forward of claims 1-4 The vehicle headlamp according to any one of the above.

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