JP2008065982A - Vehicle headlamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle headlamp of projector type in which an optimal light distribution pattern is formed while driving a bulb at a drive voltage capable of generating a halogen cycle in the bulb at daytime running. <P>SOLUTION: The vehicle headlamp 10 includes a reflecting surface of elliptic shape of which a first focal position is located near a light source and a second focal position is located extending in nearly horizontally frontward in light irradiation direction and which reflects light from the light source frontward in irradiation direction, a projection lens of which focal position on the light source side is arranged so as to be located near the second focal position of the reflecting surface at the front part of the light irradiation direction of the reflecting surface, and a control part capable of adjusting the emission intensity of the light source. The light source is moved relatively backward along the optical axis against at least a part of the reflecting surface by a movement means, and the control part drives the light source so that it reaches the maximum luminous intensity of light distribution pattern. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a projector-type vehicle headlamp that is used, for example, as a headlamp or auxiliary headlamp provided at the front of an automobile, and more particularly to a vehicle headlamp that is also used as a daytime running lamp.

Conventionally, such a vehicle headlamp is configured, for example, as shown in FIG.
That is, in FIG. 8, a vehicle headlamp 1 is a so-called traveling beam projector type vehicle headlamp, and includes a bulb 2 as a light source, a reflecting surface 3, a projection lens 4, and a battery 5. Has been.

  The bulb 2 is a bulb generally used for automobile headlamps or auxiliary headlamps, and is composed of a halogen bulb having a known configuration.

The reflective surface 3 is composed of an elliptical reflective surface having a first focal point (rear focal point) F1 in the vicinity of the bulb 2 and a long axis extending substantially horizontally toward the front in the light irradiation direction. It is formed as a 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, and its focal point on the light source side (rear side) is disposed in the vicinity of the second focal position F2 of the reflecting surface 3.
Thereby, the projection lens 4 collects light traveling forward from the bulb 2 or the reflecting surface 3 in the light irradiation direction, and irradiates the light forward in the light irradiation direction.

  The battery 5 has a known configuration, and supplies a predetermined drive voltage to the valve 2 via a switch circuit (not shown).

According to the vehicle headlamp 1 having such a configuration, when power is supplied from the battery 5 to the bulb 2, the bulb 2 emits light. The light emitted from the bulb 2 is reflected directly or by the reflecting surface 3, travels forward in the light irradiation direction toward the vicinity of the second focal point F 2 of the reflecting surface 3, and is focused by the projection lens 4 while being focused. Irradiated forward in the irradiation direction.
As a result, a light distribution pattern for a traveling beam as shown in FIG. 9 is formed. In this case, the central luminous intensity (maximum luminous intensity) is, for example, about 54000 cd with respect to the driving voltage of 12.8V.

Incidentally, in recent years, from the viewpoint of safety, in order to increase the visibility of the vehicle, daytime lighting of the vehicle headlamp has attracted attention. However, daytime lighting of the vehicle headlamp 1 is a burden on the battery. End up.
For this reason, in addition to the vehicle headlamp 1, an additional vehicle lamp has been provided as a so-called daytime running lamp.
However, since such a daytime running lamp requires an additional vehicle lamp in addition to the vehicle headlamp 1, the cost increases.

On the other hand, among the vehicle headlamps, a method of using a vehicle headlamp for a traveling beam as a daytime running lamp is conceivable.
As shown in FIG. 10, the light distribution as a daytime running lamp is performed by setting the drive voltage from the battery 5 of the vehicle headlamp 1 to an appropriate voltage (for example, about 4.0 V) by the control unit 6. The central luminous intensity of the pattern is set to a level that is not dazzling (for example, about 1000 cd or less).
As a result, a light distribution pattern for a daytime running lamp as shown in FIG. 11 is formed.

  Here, the control unit 6 includes, for example, a resistor and a pulse control circuit. As a result, the drive voltage from the battery 5 is substantially lowered to the low voltage described above and supplied to the valve 2.

  In contrast, Patent Document 1 discloses a vehicle headlamp in which an upper part of a reflector and a shade are movably arranged.

  According to this configuration, by moving the upper part of these reflectors and the shade, the shade is retracted from the optical path during the traveling beam. In addition, the upper part of the reflector is moved so that the focal point of the upper part of the reflector is located in the vicinity of the light source, and the upper and lower parts of the reflector irradiate forward in the light irradiation direction to form a light distribution pattern for the traveling beam. The

In the case of a passing beam, the shade is inserted into the optical path to block a part of the light from the light source toward the lower part of the reflector, and the upper part of the reflector is positioned so that the focal point of the upper part of the reflector is located away from the light source. It is moved and irradiated toward the front of the light irradiation direction by the upper part of the reflector, so that a light distribution pattern for a low beam can be obtained.
Japanese Utility Model Publication No. 07-001503

By the way, in the bulb 2, tungsten evaporated from the filament of the light source is combined with the halogen by a so-called halogen cycle, circulates in the bulb 2, and when it approaches the vicinity of the filament again, it is decomposed by the heat of the filament and halogenated. It is supposed to leave and return to the filament again.
In such a halogen cycle, the bond between tungsten and halogen is generally maintained at 250 ° C. or higher.

  However, as described above, when the driving voltage is adjusted to be low (for example, about 4.0 V) by the control unit 6 and power is supplied to the valve 2, the temperature inside the valve 2 becomes 250 ° C. or lower. The halogen cycle is not generated. For this reason, tungsten adheres to the inner surface of the glass of the bulb 2, and the life of the bulb 2 is remarkably shortened. In addition, the glass inner surface of the bulb 2 is teased by the attached tungsten, and the luminous intensity is reduced.

  Furthermore, the light distribution pattern for the daytime running lamp shown in FIG. 11 is basically the same as the light emission intensity distribution of the light distribution pattern of the traveling beam, the central luminous intensity is higher than the other parts, and the drive For example, the voltage is about 1090 cd with respect to about 4.0V. For this reason, the light distribution pattern is bright only in the vicinity of the center and the surroundings are very dark, and the visibility, which is the main purpose of the daytime running lamp, is reduced.

In the vehicle headlamp according to Patent Document 1, the light distribution pattern of the traveling beam and the passing beam is switched by moving the upper part of the shade and the reflector, and used as a daytime running lamp. Is not even assumed.
Therefore, Patent Document 1 is completely different from the present invention in its purpose, configuration and effect.

  From the above points, the present invention is optimal for a daytime running lamp with a simple configuration, while driving the bulb with a driving voltage that can generate a halogen cycle in the bulb when used as a daytime running lamp. It is an object of the present invention to provide a projector-type vehicle headlamp that forms a light distribution pattern.

  According to the present invention, the first object is located near the light source so that the light from the halogen light bulb and the light from the light source are reflected forward in the light irradiation direction. A concave ellipsoidal reflective surface facing forward in the light irradiation direction arranged so that the focal position is positioned on the optical axis of the light source extending substantially horizontally in front of the light irradiation direction, and the reflection surface in front of the light irradiation direction. On the optical axis of the light source, a convex projection lens arranged so that the focal position on the light source side is located near the second focal position of the reflecting surface, and the voltage supplied to the light source are controlled. A control unit; and a moving unit that moves the position of the light source that is relatively movable along the optical axis with respect to the first focal position of the reflecting surface. The relative position of the light source with respect to the first focal position of the reflecting surface And the control unit controls the voltage supplied to the light source to a lower voltage than when the light source is near the first focal position of the reflecting surface. Achieved by headlamps.

  In the vehicle headlamp according to the present invention, preferably, the light source is movable rearward along the optical axis with respect to the fixedly arranged reflecting surface, and the moving means moves the light source rearward. Move to.

  In the vehicle headlamp according to the present invention, preferably, at least a part of the reflecting surface is movable forward in the light irradiation direction along the optical axis with respect to the light source fixedly arranged, and the moving means includes At least a part of the reflecting surface is moved forward in the light irradiation direction.

  According to the above configuration, the light source emits light by power supply from the battery, and the light emitted from the light source is reflected directly or by the reflecting surface and travels toward the second focal position, and further through the projection lens. The light is irradiated forward in the light irradiation direction.

Here, at the time of traveling beam, the light source is located near the first focal position of the reflecting surface, so that the light reflected by the reflecting surface is focused toward the second focal position, and further the projection lens. It irradiates toward the light irradiation direction front via.
The light source is driven by a relatively high voltage, for example, about 12.8 V, supplied from the battery.

Therefore, a light distribution pattern for the traveling beam having a high center light intensity optimum for the traveling beam is formed.
In this case, the light reflected by the reflecting surface is focused toward the second focal position, that is, the focal position on the light source side of the projection lens, so that the light is more focused near the center and is higher near the center. The maximum luminous intensity will be obtained.

On the other hand, during daytime running lamps, the light reflected by the reflecting surface is moved by the moving means because the relative light source position is located rearward from the vicinity of the first focal position of the reflecting surface. Is focused toward a position shifted to the front side from the second focal position, and further, the central luminous intensity decreases toward the front of the light irradiation direction through the projection lens, and the light is further diffused and irradiated.
In the daytime running lamp, the light source is driven by a relatively low voltage, for example, about 6.9 V, supplied by the control unit.

Accordingly, a light distribution pattern having a central luminous intensity optimum for a daytime running lamp is formed.
In this case, the light reflected by the reflecting surface is focused toward the second focal position, that is, the position shifted forward from the focal position on the light source side of the projection lens, and is thus irradiated forward in the light irradiation direction. The light is slightly diffused as compared with the traveling beam, and the central luminous intensity does not protrude from the peripheral luminous intensity to be high, and a light distribution pattern having a more uniform luminous intensity is formed as a whole.
Thereby, high visibility can be ensured. In addition, in order to provide the optimum central luminous intensity for the daytime running lamp, the control unit can supply a higher voltage than the conventional one, for example, about 6.9 V to the light source.

  Therefore, the inside of the halogen bulb as the light source can be maintained at a temperature higher than the temperature at which the halogen cycle occurs. For this reason, tungsten which is a filament material does not adhere to the glass inner surface of the bulb. Thereby, the lifetime of the light source is not significantly shortened, and the luminous intensity is not reduced.

  The light source can move relatively rearward along the optical axis with respect to the fixedly arranged reflecting surface, and the moving means moves the light source backward. Thereby, a light source will shift | deviate back from the 1st focus position of a reflective surface.

At least a part of the reflection surface is movable forward in the light irradiation direction along the optical axis with respect to the fixedly arranged light source, and the moving means moves at least a part of the reflection surface forward in the light irradiation direction. Move to. Thereby, a light source will shift | deviate back from the 1st focus position of a reflective surface.
In this case, a portion of the reflecting surface where the light from the light source is focused near the center is moved forward in the light irradiation direction. Thereby, a central luminous intensity can be reduced efficiently.

  In this way, according to the present invention, with a simple configuration, when used as a daytime running lamp, the daytime running lamp can be converted into a daytime running lamp while driving the bulb with a driving voltage that can generate a halogen cycle in the bulb. It is possible to provide a projector type vehicle headlamp for a traveling beam so as to form an optimal light distribution pattern.

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 is particularly limited 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 a so-called traveling beam projector type vehicle headlamp, and controls a bulb 11 as a light source, a reflecting surface 12, a projection lens 13, and a bulb 11. And a moving means 15 for moving the bulb 11 in the optical axis direction.

  The bulb 11 is a bulb generally used for automobile headlamps or auxiliary headlamps, and is composed of a halogen bulb having a known configuration, and its optical axis O is substantially forward in the light irradiation direction. It is horizontally arranged, fixed and held by the socket 11a, and supplied with power from the outside.

The reflection surface 12 is formed in a concave shape so as to reflect the light from the bulb 11 forward in the light irradiation direction, and the first focal position F1 is in the vicinity of the light emitting point of the bulb 11 Located in. Further, the second focal position F2 is configured as an elliptical reflecting surface so as to be positioned on the optical axis O extending forward from the bulb 11 in the light irradiation direction on the front side in the light irradiation direction.
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 13 is composed of a convex lens, and is disposed on the optical axis O so that the focal point on the light source side is located in the vicinity of the second focal position F2 of the reflecting surface 12.
Thereby, the projection lens 13 collects the light traveling forward from the bulb 11 or the reflecting surface 12 in the light irradiation direction, and irradiates it forward in the light irradiation direction.

The control unit 14 supplies a drive voltage from a battery (not shown) to the valve 11 via a switch circuit (not shown).
Further, the control unit 14 includes a resistance or a pulse control device or the like so that the drive voltage from the battery can be adjusted to a desired voltage.
Thereby, the drive voltage of the battery is controlled by the control unit 14 to an optimum voltage (for example, about 6.9 V) when the bulb 11 is caused to emit light as a daytime running lamp.

  The moving means 15 moves the bulb 11 backward on the optical axis O from the first position shown in FIG. 1 to the second position shown in FIG. It is comprised from the appropriate drive means.

The vehicle headlamp 10 according to the embodiment of the present invention is configured as described above, and light is emitted from the light emitting unit of the bulb 11 when the bulb 11 is supplied with power from the control unit 14.
The light emitted from the bulb 11 is reflected directly or by the reflection surface 12 and proceeds forward in the light irradiation direction toward the vicinity of the second focal point F2 of the reflection surface 12, and further focused by the projection lens 13, Irradiated forward in the light irradiation direction.

Here, at the time of the traveling beam, the bulb 11 is located at the first position shown in FIG. 1, that is, near the first focal position F1 of the reflecting surface 12, and the controller 14 causes a relatively high voltage from the battery. For example, 12.8V is supplied.
As a result, the light emitted from the bulb 11 is reflected by the reflecting surface 12, then converges toward the second focal point F 2, and is irradiated forward through the projection lens 13 in the light irradiation direction.
At this time, the image of the bulb 11 formed at the second focal point F <b> 2 of the reflecting surface 12 is projected forward by the projection lens 13 in the light irradiation direction.
Therefore, as shown in FIG. 3, the light distribution pattern for the traveling beam at this time has a high central luminous intensity and an optimum central luminous intensity of the traveling beam, for example, about 54000 cd, and the distance visibility is good.

On the other hand, when used as a daytime running lamp, the bulb 11 is moved rearward along the optical axis O by the moving means 15 and is positioned at the second position shown in FIG.
As a result, the bulb 11 is positioned at a position displaced from the first focal position F1 of the reflecting surface 12 by a predetermined distance, for example, about 4 to 5 mm. Further, a relatively low voltage adjusted by the control unit 14, for example, about 6.9V is supplied.
As a result, the light emitted from the bulb 11 is reflected by the reflecting surface 12, and then converges toward the front side F3 of the second focal point F2, and is irradiated forward through the projection lens 13 in the light irradiation direction. .

At this time, the image of the bulb 11 formed on the front side of the second focal point F2 of the reflecting surface 12 is projected in a blurred state by the projection lens 13 in front of the light irradiation direction as compared with the traveling beam. .
Accordingly, as shown in FIG. 4, the light distribution pattern for the traveling beam at this time has a central luminous intensity that is not so high, and is an optimal central luminous intensity of the daytime running lamp, for example, about 880 cd. Further, the irradiation light is diffused by the projection of the bulb image in the above-described blurred state. For this reason, the surrounding light intensity that affects visibility is also secured to some extent.
Thereby, the light distribution pattern which has a light intensity required as a daytime running lamp over a wide angle range is formed. For this reason, the visibility of the vehicle body is improved.

Further, in this case, since the central luminous intensity in the light distribution pattern is not so high, in order to ensure the central luminous intensity as a daytime running lamp, a driving voltage higher than that in the past is supplied to the bulb 11.
Accordingly, the driving voltage of the bulb 11 is, for example, about 6.9 V, and a voltage that maintains a temperature of 250 ° C. or more sufficient for generating a halogen cycle inside the bulb 11. Certain tungsten does not adhere to the glass inner surface of the bulb 11. Thereby, the lifetime of the bulb 11 is not shortened, and the glass inner surface of the bulb 11 is not browned and the luminous intensity is not lowered.

Here, in general, the halogen bulb constituting the bulb 11 tends to have a longer life as the voltage decreases, as shown in FIG.
However, the halogen bulb does not generate a halogen cycle as described above with respect to a driving voltage that is not normally used as in a daytime running lamp, as shown in FIG. Thus, the lifetime is significantly shortened as the voltage is lowered.
Therefore, the lifetime of the halogen bulb was about 250 hours with respect to the driving voltage (about 4.0 V) when used as a conventional daytime running lamp.
In contrast, the driving voltage when used as a daytime running lamp according to the present invention is about 6.9V. For this reason, the lifetime of the halogen bulb can be significantly increased to about 2200 hours. This is considered to be due to the fact that the halogen cycle surely occurs in the bulb 11.

[Example 2]
FIG. 7 shows a configuration of a second embodiment of the vehicle headlamp according to the present invention.
7, the vehicle headlamp 20 has substantially the same configuration as that of 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 20 differs from the vehicle headlamp 10 shown in FIG. 1 only in that a moving means 21 for moving the reflecting surface 12 forward in the light irradiation direction is provided instead of the moving means 15. It has become.

The moving means 21 moves the reflecting surface 12 by a predetermined distance (for example, about 4 to 5 mm) forward in the light irradiation direction from the first position shown in FIG. For example, it is composed of appropriate driving means such as a motor and a solenoid.
Thereby, the bulb 11 is moved rearward relative to the reflecting surface 12 on the optical axis O.

  According to the vehicle headlamp 20 having such a configuration, it operates in the same manner as the vehicle headlamp 10 of the first embodiment shown in FIG. 1 and has a more uniform luminous intensity distribution when used as a daytime running lamp. A pattern is formed. Further, since the drive voltage of the bulb 11 can be made relatively high as in the first embodiment, the halogen cycle is surely generated. Thereby, the lifetime of the bulb 11 is not shortened, and the browning of the glass inner surface of the bulb 11 can be suppressed.

In the vehicle headlamp 20 having the above-described configuration, the moving means 21 is configured to move the entire reflecting surface 12. However, the present invention is not limited to this, and the light distribution pattern for the traveling beam is not limited to this. A region where the light is focused near the center may be divided from other regions, and only this region may be moved by the moving means 21.
Thereby, when used as a daytime running lamp, the projected image near the center of the light distribution pattern is blurred, and the central luminous intensity is slightly lowered. For this reason, the same effect as the case where the reflection surface 12 whole is moved is acquired.

In the above-described embodiment, the vehicle headlamp is configured for a traveling beam. However, the present invention is not limited to this, and it is apparent that the present invention can be applied to a vehicle headlamp that is also used as a traveling beam / passing beam. It is.
In this case, a light blocking member for blocking a part of the light reflected by the reflecting surface to form a cut-off line is provided.

  In this way, according to the present invention, with a simple configuration, when used as a daytime running lamp, the daytime running lamp can be converted into a daytime running lamp while driving the bulb with a driving voltage that can generate a halogen cycle in the bulb. An extremely excellent projector-type vehicle headlamp that can form an optimal light distribution pattern 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 side view which shows the time of use as a daytime running lamp in the vehicle headlamp of FIG. It is a graph which shows the light distribution pattern at the time of the traveling beam in the vehicle headlamp of FIG. It is a graph which shows the light distribution pattern at the time of use as a daytime running lamp in the vehicle headlamp of FIG. It is a graph which shows the lifetime with respect to the control part voltage of a halogen bulb. It is a graph which shows the lifetime with respect to the low voltage of a halogen bulb. 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 an example of the conventional vehicle headlamp. It is a graph which shows the light distribution pattern at the time of the traveling beam of the vehicle headlamp of FIG. It is a schematic side view which shows the time of use as a daytime running lamp of the vehicle headlamp of FIG. It is a graph which shows the light distribution pattern at the time of use as a daytime running lamp of the vehicle headlamp of FIG.

Explanation of symbols

10 Vehicle headlights 11 Bulb (light source)
DESCRIPTION OF SYMBOLS 12 Reflecting surface 13 Projection lens 14 Control part 15 Moving means 20 Vehicle headlamp 21 Moving means

Claims (3)

A light source consisting of a halogen bulb,
On the optical axis of the light source, the first focal position is located near the light source and the second focal position extends substantially horizontally forward in the light irradiation direction so that light from the light source is reflected forward in the light irradiation direction. A concave ellipsoidal reflective surface facing forward in the direction of light irradiation arranged to be located at
A convex projection lens disposed on the optical axis of the light source in front of the light irradiation direction of the reflecting surface, and arranged so that the focal position on the light source side is located near the second focal position of the reflecting surface;
A control unit for controlling a voltage supplied to the light source;
Moving means for moving the position of the light source that is movable relative to the first focal position of the reflecting surface along the optical axis,
When the moving means moves the relative position of the light source with respect to the first focal position of the reflecting surface to the rear, and the control unit has the light source near the first focal position of the reflecting surface. A vehicle headlamp, characterized in that the voltage supplied to the light source is controlled to a lower voltage. The light source is movable rearward along the optical axis with respect to the fixedly arranged reflecting surface;
The vehicle headlamp according to claim 1, wherein the moving means moves the light source backward. At least a part of the reflecting surface is movable along the optical axis in the light irradiation direction with respect to the fixedly arranged light source,
The vehicle headlamp according to claim 1, wherein the moving means moves at least a part of the reflecting surface forward in the light irradiation direction.

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