JP2009231068A - Vehicle headlamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle headlamp utilizing a light guide plate to readily form a light distribution pattern as a DRL. <P>SOLUTION: In the vehicle headlamp including a light guide plate unit 20 having the light guide plate 21 having a surface acting as a light outgoing plane 21b and a light source 22 opposed to an end face of the light guide plate and a convex projection lens 11 condensing outgoing light from the light outgoing plane of the light guide plate 21 to emit the light forward in a light emitting direction, the headlamp 10 includes at least one additional light source 13 disposed between the light guide plate unit and the convex lens and is configured such that light from the additional light source reflects from the light outgoing plane of the light guide plate to be emitted forward in the light emitting direction via the projection lens to form the light distribution pattern of the DRL. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle headlamp such as a headlamp and an auxiliary headlamp composed of a light guide plate unit and a convex lens using a plurality of point-like or linear light sources, and more particularly, a vehicle having a data imprinting light function. Concerning headlamps.

  Conventionally, as a vehicular lamp using a light guide plate, for example, a headlamp using a vehicular lamp according to Patent Document 1 is known.

The vehicle lamp according to Patent Document 1 is configured as shown in FIGS. 12 and 13.
That is, in FIGS. 12 and 13, the vehicle lamp 1 is fixedly installed on the housing 2 so as to seal the housing 2 having an opening 2 a for emitting light and the opening 2 a of the housing 2. A light-transmitting cover member 3, a light-incident surface 4a provided in a plate shape inside the housing 2, and formed on a side surface for taking in light, and a light-emitting surface 4b on the front surface facing the cover member; A light guide plate 4 on which a scattering pattern 4c for scattering light incident on the light incident surface 4a toward the light exit surface 4b is formed, and provided adjacent to the light incident surface of the light guide plate 4. Is provided on the rear surface of the light guide plate 4, and a reflection plate 4 d for reflecting light on the front surface of the light guide plate 4.
On the light incident surface and / or the light emitting surface of the cover member 3, a lens pattern 3 c for imparting a certain pattern to emitted light is formed.

In the vehicle lamp 1, as shown in FIG. 13, the light emitted from the light source 5 enters the inside from the side surface (light incident surface) 4 a of the light guide plate 4 and totally reflects the inside of the light guide plate 4. The traveling light is scattered by the scattering pattern 4 c formed on the rear surface of the light guide plate 4 and emitted to the front surface (light emitting surface) 4 b of the light guide plate 4.
The light emitted to the front surface of the light guide plate 4 is irradiated forward with an appropriate pattern by the cover member 3 on which the lens pattern is formed.
Here, the light source 5 is configured by arranging a plurality of light emitting diodes (LEDs), and a desired light distribution characteristic can be obtained by arranging a lens or the like on the front surface of the light source 5. .

On the other hand, the present applicant has proposed a vehicle headlamp as shown in FIGS.
In FIG. 14, the vehicle headlamp 6 includes a light guide plate unit 7 and a projection lens 8 that focuses light from the light guide plate unit 7.
The projection lens 8 is composed of a convex lens, for example, a single lens, a cylindrical lens, or a combination thereof, and the focal position F on the light guide plate unit 7 side is on the light exit surface of the light guide plate unit 7. It is arranged to be located.

The light guide plate unit 7 is disposed so as to emit light forward in the light irradiation direction in the vicinity of the center of the rear end surface of the box-shaped housing 6a that opens toward the front of the vehicle headlamp 6. .
Here, the light guide plate unit 7 includes a light guide plate 7a and a plurality of LEDs (not shown) as light sources.

In the case shown in the drawing, the light guide plate 7a is made of a flat plate-like light-transmitting material, that is, a material transparent in the visible light region.
Here, the light guide plate 7a is made of a transparent resin or glass generally used for optical applications, such as polycarbonate and acrylic resin.

  The light guide plate 7a is configured such that one side thereof, the upper or lower end face in FIG. 14 is an incident face, and the left side face is a light exit face, and its back face (bottom face) and both left and right side faces are It is covered with a housing made of a light shielding material.

Further, the light guide plate 7a preferably has, for example, a vehicle headlamp so that its light exit surface has a shape corresponding to the light distribution pattern to be irradiated, that is, a shape obtained by reducing and reversing the light distribution pattern. It is formed so as to have a beam cut-off pattern shape.
The light guide plate 7a includes a luminance control element (not shown), for example, a dot-like or groove-like microstructure on the front surface and / or back surface thereof.

According to the vehicle headlamp 6 having such a configuration, the light emitted from the light guide plate unit 7 is converged by the projection lens 8 and is irradiated substantially parallel to the light irradiation direction.
At that time, the front surface and / or the back surface of the light guide plate 7a constituting the light guide plate unit 7 includes a luminance control element. Therefore, the light irradiated forward from the light guide plate unit 7 via the projection lens 8 has a predetermined luminance distribution.

As for the light distribution characteristic provided by the light guide plate 7a, when the directivity characteristic is wide, the light guide plate unit 7 is disposed substantially perpendicular to the optical axis as shown in FIG. In the case where the light guide plate unit 7 is narrow, as shown in FIG. 15, the light guide plate unit 7 is inclined forward so that the direction in which the maximum luminous intensity of the directivity characteristic is given coincides with the optical axis direction.
Special table 2006-509343

By the way, in the vehicle lamp 1 according to Patent Document 1, light is extracted from the light guide plate 4 by scattering light by the scattering pattern 4c. A light distribution pattern is formed by a plurality of individual lens patterns 3c. For this reason, the optical setting of each lens pattern 3c becomes complicated.
For example, with respect to a certain part of the lens pattern, scattered light from the light guide plate 4 enters from a peripheral part other than the focal position. Accordingly, it is very difficult to form a specific light distribution pattern or cutoff line in front of the lens pattern 3c.
The light distribution pattern is formed by a lens pattern. For this reason, it was impossible to switch the light distribution pattern.

Therefore, when the vehicle lamp 1 is also used as a so-called daytime running light (hereinafter referred to as DRL), in order to use it as a daytime running light, the light emission intensity of the light source 5 is reduced, Alternatively, only a part is caused to emit light.
However, the light distribution control is performed by the cover member 3 on which the lens pattern 3c is formed. Accordingly, it has not been possible to realize a DRL dedicated light distribution pattern that is different from the light distribution pattern of the traveling beam and the passing beam.

On the other hand, in the vehicle headlamp 6 shown in FIG. 14 or FIG. 15, the light distribution pattern is formed in the vicinity of the focal point of the projection lens 8 with a light distribution pattern controlled by the light emitting surface of the light guide plate 7a. This is irradiated forward by the projection lens 8 in the light irradiation direction. For this reason, when the vehicle headlamp 6 also serves as a DRL, in order to form a DRL light distribution pattern, the light emission intensity of the light guide plate unit 7 is similarly reduced, or only a part of the light is emitted. Become.
However, the light distribution control is performed by the luminance control element on the front surface and / or the back surface of the light guide plate 7a. Accordingly, it is impossible to realize a DRL dedicated light distribution pattern that is different from the light distribution pattern of the traveling beam and the passing beam.

  In view of the above, an object of the present invention is to provide a vehicle headlamp that can easily form a light distribution pattern as a DRL using a light guide plate with a simple configuration.

  According to the present invention, a light guide plate made of a transparent material in a flat or wedge-shaped visible light region whose surface is a light emitting surface, and a point-like shape arranged opposite to one end surface of the light guide plate. Alternatively, a light guide plate unit composed of a linear light source and a brightness control member provided on the front and / or back surface of the light guide plate, and light emitted from the light exit surface of the light guide plate is converged and directed forward in the light irradiation direction. A vehicle-mounted headlamp that includes a convex projection lens that irradiates the light source with at least one additional light source disposed between the light guide plate unit and the projection lens or below the light guide plate unit. The light from the additional light source is reflected by the light guide plate unit and irradiated forward through the projection lens in the light irradiation direction to form a second light distribution pattern different from the predetermined light distribution pattern. And the car It is achieved by the headlamp.

  In the vehicle headlamp according to the present invention, the light from the additional light source preferably forms a DRL light distribution pattern on the projection lens side surface of the light guide plate unit.

  In the vehicle headlamp according to the present invention, preferably, the light guide plate unit is aligned with the optical axis of the projection lens in order to align the direction of the maximum luminous intensity of the light emitted from the light guide plate with the optical axis of the projection lens. It is arranged to be inclined.

  In the vehicle headlamp according to the present invention, preferably, at least a part of the projection lens is a cylindrical lens whose axis extends in the lateral direction.

  In the vehicle headlamp according to the present invention, preferably, the projection lens is formed as a cylindrical lens having both ends formed as convex lenses and an axis extending laterally in a region between the projection lenses. Are arranged in a plane perpendicular to the axis of the cylindrical lens and passing through the boundary portion with the convex lens.

  In the vehicle headlamp according to the present invention, preferably, the light exit surface of the light guide plate has a shape corresponding to the cut-off pattern.

  The vehicle headlamp according to the present invention preferably includes a light guide unit that reduces unevenness in luminance of light from the light source in regions adjacent to the light source side edges of the front and back surfaces of the light guide plate, A region adjacent to the light source side edge on the surface of the light guide plate is provided with a reflection sheet or a light shielding sheet having a shape corresponding to the cut-off pattern and reflecting light from the surface of the light guide plate into the light guide plate, The surface on the projection lens side of the reflection sheet or the light shielding sheet or the housing holding the reflection sheet is a reflection surface for reflecting the light of the additional light source toward the projection lens.

  The vehicle headlamp according to the present invention preferably includes a light guide unit that reduces unevenness in luminance of light from the light source in regions adjacent to the light source side edges of the front and back surfaces of the light guide plate, A light source side edge of the surface of the light guide plate is provided with a reflection sheet or a light shielding sheet that has a shape corresponding to the cut-off pattern and reflects light from the surface of the light guide plate into the light guide plate. The sheet is configured to be retractable from the surface of the light guide plate.

  In the vehicle headlamp according to the present invention, preferably, the light guide plate is formed to be curved corresponding to the aberration of the projection lens.

According to the said structure, when using as a vehicle headlamp, the light source of the said light-guide plate unit drives and it light-emits. Thereby, the light emitted from the light source of the light guide plate unit is incident from one end surface of the light guide plate, and after being repeatedly reflected on the inner surface of the light guide plate, is emitted to the outside from the surface of the light guide plate.
At that time, the light incident on the back surface and the front surface of the light guide plate from the inside is controlled by the brightness control element, the brightness distribution of the light exit surface, passes through the surface of the light guide plate, and exits toward the projection lens. .
Thereby, the luminance distribution on the light emitting surface is projected forward of the vehicle through the projection lens, and irradiation light having a predetermined light distribution pattern suitable for, for example, a passing beam or a fog lamp is obtained.

Further, when the additional light source is driven to emit light, the light from the additional light source illuminates the projection lens surface side of the light guide plate unit with a second illuminance distribution, and the light hitting the light emitting surface is the light of the light guide plate unit. After entering the light guide plate, a part is totally reflected by the luminance control element on the back surface, and most of the light is refracted and transmitted through the luminance control element on the back surface and reflected by the reflective sheet on the back surface side of the light guide plate unit. Then, it is refracted and transmitted through the light exit surface to form a second luminance distribution, proceeds toward the projection lens, converges by the projection lens, and is irradiated forward in the light irradiation direction. Thereby, the 2nd light distribution pattern different from the predetermined light distribution pattern by the light from the said light-guide plate unit is formed.
As described above, the light irradiated by the additional additional light source on the projection lens surface side of the light guide plate unit is affected by the action of the luminance control element. However, since the thickness of the light guide plate is smaller than the size of the second illuminance distribution illuminated by the additional light source, the movement distance of the light refracted by the luminance control element in the direction parallel to the light exit surface is small. This can be easily solved by adjusting the position and size of the illuminance distribution.
Further, the influence of the second luminance distribution on the light direction due to the action of the luminance control element can be solved by adjusting the direction of the additional light source. Specifically, when the direction of the reflected light from the light guide plate reflection unit of the additional light source is upward as compared with the case where there is no luminance distribution control element (in the case of a plane), Rotate the optical axis of the additional light source in the downward direction with the focal line of the projection lens as the axis, and conversely if it deviates downward, rotate it in the reverse direction to project the reflected light from the light guide plate unit. What is necessary is just to make it enter into a lens.
Thus, by illuminating the light guide plate unit with the second illuminance distribution and using the light guide plate unit as a reflection plate, a second light distribution pattern different from a predetermined light distribution pattern such as a passing beam or a fog lamp can be easily obtained. Can be set.

  When the second luminance distribution forms a DRL light distribution pattern, an optimal light distribution pattern for a DRL different from the predetermined light distribution pattern can be easily obtained.

When the light guide plate unit is arranged to be inclined with respect to the optical axis of the projection lens in order to align the direction of the maximum luminous intensity of the light emitted from the light guide plate with the optical axis of the projection lens. With respect to the light emitted from the light guide plate unit, the direction in which the light intensity of the light emitted from the light guide plate is highest can be aligned with the optical axis of the projection lens. Thereby, it becomes possible to make the brightness | luminance of irradiated light as high as possible.
Further, since the light guide plate is inclined, the dimension in the inclination direction can be reduced even with a relatively large light guide plate. Thereby, the resolution of the luminance control element can be relatively increased.

When at least a part of the projection lens is a cylindrical lens whose axis extends in the lateral direction, the projection lens does not have light condensing property in the lateral direction, but is sufficiently wide in the lateral direction with respect to the light guide plate unit. Arranged in the range. Thereby, the incident efficiency from the light guide plate unit is improved, and a brighter light distribution pattern can be formed.
Further, the light transmitted through the projection lens is slightly diffused in the left-right direction by the action of the cylindrical lens. Therefore, a wide light distribution pattern can be obtained on the left and right, and in the case of point-like light sources spaced in the horizontal direction, luminance unevenness between the individual light sources can be reduced.

The projection lens is formed as a cylindrical lens whose both ends are formed as convex lenses, and whose axis extends in the lateral direction in the region between them, and the additional light source is perpendicular to the axis of the cylindrical lens and is a convex lens. When arranged in a plane passing through the boundary portion, the additional light source is arranged on the central axis with respect to the convex lens near both ends of the projection lens. Therefore, the light that is emitted from the additional light source and reflected by the light guide plate unit and incident on the projection lens is refracted inward by the convex portion.
Therefore, the luminous intensity near the center in the light distribution pattern is increased.

  When the light emission surface of the light guide plate has a shape corresponding to the cut-off pattern, the light guide plate unit can form the cut-off pattern. For this reason, the light shielding member for forming a cut-off pattern becomes unnecessary, and the vehicle headlamp can be configured more easily and at low cost.

A region adjacent to the light source side edge on the front and back surfaces of the light guide plate is provided with a light guide part that reduces luminance unevenness of light from the light source, and adjacent to the light source side edge on the surface of the light guide plate The light guide plate has a shape corresponding to the cut-off pattern and includes a reflection sheet or a light shielding sheet that reflects light from the surface of the light guide plate into the light guide plate. By repeating reflection by the light guide between the front and back surfaces of the light guide plate in a region adjacent to the edge, luminance unevenness due to the interval between a plurality of point-like light sources arranged side by side is reduced. For this reason, a predetermined light distribution pattern with more uniform luminance can be formed. In addition, a cut-off pattern is formed on the predetermined light distribution pattern based on the shape of the reflection sheet or the light shielding sheet by the reflection sheet or the light shielding sheet.
When the second light distribution pattern is formed by the additional light source, the reflection lens or the light shielding sheet or the projection lens side of the housing that holds the reflection sheet is used as a reflection surface, so that the second cutoff pattern is eliminated. A luminance distribution can be obtained. That is, a second light distribution pattern that requires light above the horizontal line as in DRL can be obtained.

  When the reflection sheet or the light shielding sheet is configured to be retractable from the surface of the light guide plate, when the second light distribution pattern is formed by the additional light source, the reflection sheet or the light shielding sheet is disposed on the surface of the light guide plate. By retracting from, it is possible to obtain a second light distribution pattern that can be reflected by the entire light guide plate unit and that requires light above the horizontal line as in DRL.

  When the light guide plate is formed to be curved corresponding to the aberration of the projection lens, aberrations such as spherical aberration of the projection lens are corrected by the curved shape of the light guide plate. For this reason, the influence of spherical aberration can be reduced. This effect is similarly effective not only in the predetermined light distribution pattern but also in the second light distribution pattern by the additional light source.

  In this way, according to the present invention, a simple configuration can be used to easily form a predetermined light distribution pattern suitable for, for example, a passing beam and a fog lamp, and a second light distribution pattern suitable for DRL. A lightweight vehicle headlamp can be provided.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS.
The embodiments described below are reference examples and preferred 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. Unless otherwise specified, the present invention is not limited to these embodiments.

[Example 1]
FIG. 1 shows the configuration of a first embodiment of a vehicle headlamp according to the present invention.
In FIG. 1, the vehicle headlamp 10 includes a light guide plate unit 20, a projection lens 11 that focuses light from the light guide plate unit 20, a housing 12, and an additional light source 13.
The light guide plate unit 20 is configured as will be described later, and light is emitted forward in the light irradiation direction near the center of the rear end surface of the box-shaped housing 12 opened toward the front of the vehicle headlamp 10. Are arranged so as to emit light.
The projection lens 11 is composed of a convex lens, and is disposed on the light exit surface of the light guide plate unit 20 so that the focal position F on the light guide plate unit 20 side is located.

  Here, as shown in FIG. 2, the light guide plate unit 20 includes a light guide plate 21 and a plurality of LEDs 22 as light sources.

In the case shown in the drawing, the light guide plate 21 is made of a flat plate-like light-transmitting material, that is, a material transparent in the visible light region.
Here, the light guide plate 21 is made of a transparent resin or glass generally used for optical applications such as polycarbonate and acrylic resin.

The light guide plate 21 is configured such that one end thereof, the end surface on the near side in FIG. 1 is an incident surface 21a, and the upper surface is a light emitting surface 21b, and the back surface (bottom surface) and both left and right side surfaces are shielded from light. It is covered with the housing | casing 23 which consists of a property material.
In the illustrated case, the light guide plate 21 is formed in a wedge shape in cross section so that the thickness gradually decreases from the incident surface 21a to the opposite end surface. It may be formed.

Here, in the light guide plate 21, the incident surface 21a may be provided with a fine shape made of, for example, a prism or a circular arc or roughened in order to improve the incident efficiency.
On the other hand, the light guide plate 21 may have a light emitting surface 21b having a prism, lenticular shape, or the like in order to improve luminance or adjust light distribution.

Further, as shown in FIG. 2, the light guide plate 21 has a light output surface 21b in a shape corresponding to a light distribution pattern to be irradiated, that is, a shape obtained by reducing and reversing the light distribution pattern, for example, in a vehicle. It is formed so as to be in the shape of a cut-off pattern of the passing beam of the headlamp.
Therefore, the light guide plate 21 has an end surface 21a on the front side forming a step portion near the center as shown in FIG.

Furthermore, the light guide plate 21 has a prism array (not shown) on its back surface (bottom surface).
This prism array is formed, for example, so as to extend in a sawtooth shape in cross section from the incident surface 21a toward the opposite end surface and in a bowl shape in the lateral direction.
Of the light incident from the incident surface 21a of the light guide plate 21, when the light incident on the individual prism surfaces of these prism arrays is totally reflected, it is formed so as to be inclined so that the incident angle with respect to the exit surface becomes small. ing.
As a result, most of the light incident on the light guide plate 21 is totally reflected on the inner surfaces of the individual prisms of the prism array, and is totally reflected on the upper surface of the light guide plate 21, thereby repeating the reflection.
Such reflected light gradually emerges upward from the light exit surface 21b of the light guide plate 21 when the incident angle with respect to the light guide plate 21 gradually decreases and the incident angle becomes smaller than the critical angle. Yes.

Here, in the illustrated case, the light guide plate unit 20 has an upper edge on the front side so that the direction in which the light reflected by the prism array 24 of the light guide plate 21 is emitted from the light exit surface 21b is aligned with the optical axis of the projection lens 11. It is arranged to be inclined so as to fall down.
At that time, the light guide plate unit 20 is disposed such that the position where the cut-off line on the light incident surface 21a side of the light guide plate 21 is formed is near the focal position F of the projection lens 11 on the light guide plate unit 20 side. ing.

Here, the light guide plate 21 has an optical sheet 25 (two optical sheets in the case of illustration) on the surface as necessary in order to improve the luminance of light emitted from the surface or to adjust the light distribution characteristics. 25a, 25b).
Thereby, the direction and directivity of the light emitted from the light emitting surface 21b of the light guide plate 21 are appropriately adjusted by the optical action of the optical sheet 25, and the emitted light from the light guide plate 21 is directed to the projection lens 11. Can be guided reliably.

As such optical sheets 25a and 25b, a prism sheet, a diffusion film, or the like used in a general surface light guide plate unit can be used.
Prism sheet is generally used in optical applications by imparting a prism shape by press molding or extrusion molding with a mold to a film made of thermoplastic transparent resin that is generally used in optical applications. The film made of an ultraviolet curable transparent resin can be manufactured by imparting a prism shape by a molding method such as 2P method.

  In addition, the diffusion film is formed by forming a resin or glass bead having a different refractive index on both sides or one side of a film obtained by extrusion molding composed of a thermoplastic transparent resin generally used in optical applications. Alternatively, it can be produced by mixing a resin having a different refractive index or a glass bead into a thermoplastic transparent resin generally used in optical applications, and forming it into a film by extrusion or the like.

In addition, the light guide plate 21 returns light leaking from the back and side surfaces thereof into the light guide plate 21 to improve the light use efficiency from each LED 22 as a light source. A reflective film 26 may be disposed to face the end surface, the back surface, and the left and right side surfaces.
Here, as the reflective film 26, a silver film in which a high reflectance metal such as silver is formed on the surface of a transparent resin substrate such as PET by sputtering, a high reflectance white sheet, or the like is usually used.

  High reflectivity white sheet is a resin film or resin plate in which visible light diffusive reflector such as titanium oxide is added to polycarbonate resin or the like, or micropores by supercritical fluid, fine foam molding or foaming with chemical foaming agent, etc. It can be manufactured from a resin film or a resin plate formed by distributing.

When the inner surface of the housing 23 is configured as a reflective surface, at least a part of the inner surface of the housing 23 can be used instead of the reflective film 26.
In order to configure the inner surface of the housing 23 as a reflective surface, a high-reflectance metal thin film may be formed directly on the inner surface of the housing 23 made of resin or metal, for example, by vapor deposition or sputtering. .

Each LED 22 is arranged in a line so as to face the incident surface 21 a of the light guide plate 21.
Here, the LEDs 22 do not need to be arranged at equal intervals, and along the incident surface 21a of the light guide plate 21 so that a predetermined luminance distribution is obtained on the light emitting surface 21b of the light guide plate 21. They are arranged at appropriate intervals.
In addition, although each LED22 is arrange | positioned at 1 row in the figure, it is not restricted to this, You may arrange | position at multiple rows.

The additional light source 13 is a light source such as an LED, and is disposed between the light guide plate unit 20 and the projection lens 11 on the lower front side of the light guide plate unit 20, and the optical axis thereof is the projection. The lens 11 is disposed near the focal position of the lens 11 on the light guide plate unit 20 side so as to intersect the surface of the light guide plate 21.
The light emitted from the additional light source 13 strikes the projection lens side of the light guide plate unit 20 along the optical axis. After the light hitting the light emitting surface 21b enters the light guide plate 21 of the light guide plate unit, a part of the light is totally reflected by the luminance control element on the back surface of the light guide plate 21 and most of the light is refracted and transmitted through the luminance control element on the back surface. The light is reflected by the reflection sheet on the back side of the light guide plate unit, returned to the light guide plate, refracted and transmitted through the light exit surface to form a second luminance distribution, and the front of the light irradiation direction through the projection lens 11. Is irradiated.

At that time, the light guide plate unit 20 is disposed to be inclined forward. Thereby, the light from the additional light source 13 disposed on the lower front side of the light guide plate unit 20 is reflected by the light guide plate unit 20 and is irradiated to the front in the light irradiation direction without being blocked by the additional light source 13. Can be done.
At this time, the additional light source 13 is preferably configured as an LED lamp in which a lens is incorporated by molding or the like, for example, so as to condense into a horizontally long rectangle or ellipse based on the shape of the lens.
As a result, the second luminance distribution that is illuminated by the horizontally long focused light and formed on the light guide plate unit 20 is irradiated by the projection lens 11 in the light forward direction as a light distribution pattern. Therefore, by using the additional light source 13 having such a configuration, it becomes possible to satisfy, for example, a European standard DRL light distribution pattern with a bright center and wider left and right sides.

The vehicle headlamp 10 according to the embodiment of the present invention is configured as described above. First, a case where the vehicle headlamp 10 is used as a normal vehicle headlamp such as a normal passing beam will be described.
In this case, each LED 22 of the light guide plate unit 20 is applied with a drive voltage from an external drive circuit (not shown). As a result, each LED 22 is driven to emit light. In this case, the additional light source 13 does not emit light.
Light emitted from each LED 22 enters the inside from the incident surface 21a of the light guide plate 21 and is repeatedly returned to the light guide plate by the total reflection and reflection sheet 26 on the front surface, back surface, and both side surfaces of the light guide plate 21. However, it is emitted toward the projection lens 11 from the emission surface 21b.

As a result, the incident light is diffused substantially throughout the light guide plate 21, and the entire light exit surface 21 b of the light guide plate 21 emits light.
In this case, a prism array on the back side is particularly provided. Thereby, the incident light from the incident surface 21a of the light guide plate 21 efficiently travels to the light emitting surface 21b, and the light emitting surface 21b emits light with higher luminance.

The light emission shape of the light emission surface 21b of the light guide plate 21 is projected forward by the projection lens 11 in the light irradiation direction.
Thereby, the light emission shape of the light emitting surface 21b is enlarged and inverted and projected in front of the light irradiation direction.
In this case, the edge on the incident surface 21a side of the light emitting surface (front surface) of the light guide plate 21 has a shape corresponding to the cut-off pattern as shown in FIG. Thereby, the light emission shape corresponding to the light distribution pattern suitable for the passing beam in the vehicle headlamp is formed.
Therefore, this light emission shape is projected forward by the projection lens 11 in the light irradiation direction, and a light distribution pattern suitable for a passing beam of an automobile can be formed.

Here, the light emission surface 21b of the light guide plate 21 in the light guide plate unit 20 has a light emission shape corresponding to the light distribution pattern. This eliminates the need for a light-shielding member that forms a reflection surface and a cut-off line for generating a light distribution pattern, such as a conventional projector-type vehicle headlamp.
Therefore, the depth of the entire vehicle headlamp 10 is greatly reduced in the front-rear direction, and the vehicle headlamp 10 can be configured to be small and lightweight.
Further, since no light shielding member is required, the number of parts can be reduced, and the parts cost and assembly cost can be greatly reduced.

Furthermore, the incident surface 21a side of the light emitting surface 21b of the light guide plate 21 has a cut-off pattern shape. For this reason, high brightness can be easily obtained on the incident surface 21a of the light emitting surface 21b.
Therefore, the cut-off line bright / dark boundary line of the light distribution pattern formed by the incident surface 21a side can be projected clearly with high luminance.
Further, the LEDs 22 are arranged at shorter intervals in an area where high luminance is required in the light distribution pattern. Thereby, high brightness can be easily obtained.

On the other hand, the case where it uses as DRL is demonstrated below.
The additional light source is driven to emit light. Thereby, the light emitted from the additional light source is reflected by the light guide plate unit, and the reflected light passes through the projection lens 11 and proceeds forward in the light irradiation direction.
At that time, the reflected light is converged by the projection lens 11 and irradiated forward in the light irradiation direction with the DRL light distribution pattern.
In this case, the DRL light distribution pattern is formed by the lens shape of the additional light source 13 and the luminance control element of the light guide plate 21. Therefore, light is irradiated with a light distribution pattern that is optimal for DRL, which is different from a light distribution pattern as a normal vehicle headlamp.

[Example 2]
FIG. 3 shows the configuration of the light guide plate unit in the second embodiment of the vehicle headlamp according to the present invention.
In FIG. 3, the vehicle headlamp is configured in the same manner as the vehicle headlamp shown in FIG. 1, and differs only in that a light guide plate unit 30 is provided instead of the light guide plate unit 20. ing.

Compared with the light guide plate unit 20 shown in FIG. 2, the light guide plate unit 30 is not formed in the shape of a cut-off pattern in the light emission surface 21 b, and is in the edge region on the incident surface 21 a side. A light guide 31 having a predetermined width is provided.
The light guide unit 31 includes a reflection sheet 31 a placed on the surface of the light guide plate 21 in the region. In the reflection sheet 31a, the surface in contact with the light guide plate 21 is not only a reflection surface, but also the projection lens side is a reflection surface.
Furthermore, the edge 31b on the opposite side to the incident surface 21a of this reflective sheet 31a is formed in the shape corresponding to a cut-off line.
When the reflection sheet 31a is covered with a housing (not shown) for holding the reflection sheet 31a, the edge of the housing opposite to the incident surface 21a on the projection lens side has the same shape as 31b. The surface of the housing on the projection lens side is a reflecting surface.

According to the vehicle headlamp having such a configuration, in the light guide plate unit 30, the light incident on the light guide plate 21 from the incident surface 21 a is reflected by the light guide unit 31 on the back surface of the light guide plate 21 or the reflection film 26. And the reflection sheet 31a are repeatedly reflected. Thereby, the incident light is sufficiently diffused in the light guide plate 21 particularly in the left-right direction. For this reason, luminance unevenness based on the distance between the LEDs 22 can be reduced, and a cut-off pattern is formed by the contour of the edge 31b of the reflection sheet 31a.
In this case, the surface 21b of the light guide plate 21 and the reflective film 26 do not need to be formed in accordance with the shape of the cut-off line.

FIG. 4 is a diagram for explaining ray tracing of an additional light source in the second embodiment. In the light guide plate unit 30, the end 31 b of the reflection sheet in the run-up section, which creates a low beam cut-off line on the incident surface side of the projection lens, has the maximum luminous intensity of the low beam from the light guide plate at the focal position of the projection lens 11. It is tilted so as to match the optical axis.
The additional light source 13 is disposed below the light guide plate unit 30 so that the optical axis of the additional light source 13 passes through the vicinity of the focal point of the projection lens 11.
The light L2 that is emitted from the additional light source 13 and first hits the reflection sheet 31b of the light guide plate unit 30 or the casing that holds the light reflection plate 31 is specularly reflected by the reflection sheet 31b or the surface of the casing, and converged and projected by the projection lens 11 It becomes the light above the cut-off line. The light L1 that has exited from the additional light source 13 and first hits the light exit surface 21b of the light guide plate unit 30 once enters the light guide plate 21, is reflected by the reflection sheet 26, and then exits the light exit surface 21b again. At that time, although the direction of the emitted light is different from the regular reflection direction due to the influence of the luminance control element, the light is focused and projected by the projection lens 11 as the second pattern formed on the light guide plate unit, and is below the cut-off line. It becomes. Therefore, L1 and L2 are combined, and the front can be illuminated with the second light distribution pattern connected vertically.
As described above, the second light distribution pattern is based on the illuminance distribution in which the additional light source 13 illuminates the light guide plate unit. When the number of the additional light sources 13 is one, for example, if an LED having a semi-elliptical tip is used, the light guide plate unit 30 can be illuminated with an illuminance distribution obtained by reducing and reversing a wide DRL light distribution pattern on the left and right. Two or more additional light sources 13 may be arranged.
In the following embodiments, the light guide plate unit is denoted by reference numeral 20, but the structures of FIGS. 3 and 11 are also included.

[Example 3]
FIG. 5 shows a third embodiment of a vehicle headlamp according to the present invention.
In FIG. 5, the vehicle headlamp 40 has substantially the same configuration as the vehicle headlamp 10 shown in FIGS. 1 and 2, and thus the same components are denoted by the same reference numerals and description thereof is omitted. .
The vehicle headlamp 40 is different from the projection lens 11 only in that a long projection lens 41 is disposed in the horizontal direction corresponding to the long light guide plate unit 20 in the horizontal direction.

  As shown in FIG. 5A, the projection lens 41 includes two convex lenses obtained by dividing the projection lens 11, that is, the convex lens, left and right from the center and separating the projection lens 11 according to the lateral length of the light guide plate 21. 41a and a cylindrical lens 41b connecting these two convex lenses 41a.

According to the vehicle headlamp 40 having such a configuration, the vehicle headlamp 10 operates in the same manner as the vehicle headlamp 10 shown in FIGS. 1 and 2.
Furthermore, since the projection lens 41 includes the cylindrical lens 41b and the incident surface is wide in the horizontal direction, a wide light distribution pattern is formed in the horizontal direction.
Therefore, it is not necessary for the additional light source 13 to illuminate the light guide plate unit 20 widely from side to side in order to obtain the DRL light distribution.
In this case, in addition to the effect that the cylindrical lens is large on the left and right, the incident efficiency is high, and in addition to the semi-elliptical LED described in Example 2, the hemispherical LED is general and inexpensive.

Further, the light incident on the cylindrical lens 41a is slightly diffused in the left-right direction, so that a wide light distribution pattern is formed in the left-right direction, and luminance unevenness based on the distance between the LEDs 22 in the light distribution pattern can be reduced. Become.
This effect is also effective in the second light distribution pattern by the additional light source as in the case of the predetermined light distribution pattern.

Further, the light incident on the convex lenses 41a at the left and right ends of the projection lens 41 is refracted inward in the left-right direction and is irradiated forward in the light irradiation direction. For this reason, the luminous intensity near the center in the light distribution pattern is increased.
This effect is also effective in the second light distribution pattern by the additional light source as in the case of the predetermined light distribution pattern.

[Example 4]
FIG. 6 shows a configuration of a fourth embodiment of the vehicle headlamp according to the present invention.
In FIG. 6, the vehicle headlamp 50 has substantially the same configuration as the vehicle headlamp 40 shown in FIG. 5, and thus the same components are denoted by the same reference numerals and description thereof is omitted.
The vehicle headlamp 50 is provided with a projection lens 51 instead of the projection lens 41 as compared with the vehicle headlamp 40 shown in FIG.
The projection lens 51 is composed only of a cylindrical lens having an axis extending in the left-right direction.

According to the vehicle headlamp 50 having such a configuration, the vehicle headlamp 40 operates in the same manner as the vehicle headlamp 40 shown in FIG.
In this case, no convex lens is provided near the left and right ends of the projection lens 51. For this reason, the light emitted from the light guide plate 21 in the left-right direction is not condensed near the center of the light distribution pattern by the convex lens, but is reflected inward in the horizontal direction by internal reflection and contributes to the formation of the light distribution pattern.
Therefore, a desired light distribution pattern can be formed in a fog lamp or the like where the maximum luminous intensity is not so important.
Also in this case, the additional light source for obtaining the DRL light distribution does not need to illuminate the light guide plate unit 20 widely from side to side as in the third embodiment. For example, the tip may be illuminated by a hemispherical LED.

[Example 5]
FIG. 7 shows a configuration of a fifth embodiment of the vehicle headlamp according to the present invention.
In FIG. 7, the vehicle headlamp 60 has substantially the same configuration as the vehicle headlamp 40 shown in FIG. 5, and thus the same components are denoted by the same reference numerals and description thereof is omitted.
The vehicle headlamp 60 is provided with a projection lens 61 instead of the projection lens 41 as compared with the vehicle headlamp 40 shown in FIG.
The projection lens 61 is composed of a single convex lens.
This embodiment shows the most basic configuration of the present invention.

According to the vehicle headlamp 60 having such a configuration, the vehicle headlamp 40 operates in the same manner as the vehicle headlamp 40 shown in FIG.
In this case, the projection lens 61 is a single convex lens, and the cost of the lens can be suppressed low.

[Example 6]
FIG. 8 shows the configuration of a sixth embodiment of the vehicle headlamp according to the present invention.
In FIG. 8, the vehicle headlamp 70 has substantially the same configuration as the vehicle headlamp 40 shown in FIG. 5, and thus the same components are denoted by the same reference numerals and description thereof is omitted.
In the vehicle headlamp 70, the light guide plate 21 in the light guide plate unit 20 corresponds to the spherical aberration direction of the convex lens 41a of the projection lens 41 for projecting the light exit surface 21b in the region corresponding to the left and right convex lenses 41a. In order to correct this spherical aberration, it is formed to be curved.

According to the vehicle headlamp 70 having such a configuration, the vehicle headlamp 40 operates in the same manner as the vehicle headlamp 40 shown in FIG.
Further, the regions at both ends of the light guide plate 21 are curved corresponding to the spherical aberration of the convex lens 41 a of the projection lens 11, and the spherical aberration of the convex lens 41 a of the projection lens 41 is caused by the curvature of the light guide plate 21. It will be corrected.

  In this embodiment, in addition to the effect that the spherical aberration is corrected, the reflected light of the additional light source 13 is collected in the left-right direction at the curved portion of the light guide plate unit 21, and the incident efficiency to the projection lens 41 is increased. There is an effect.

[Example 7]
FIG. 9 shows the configuration of a seventh embodiment of the vehicle headlamp according to the present invention.
In FIG. 9, the vehicle headlamp 80 has substantially the same configuration as that of the vehicle headlamp 60 shown in FIG.
In the vehicle headlamp 80, as compared with the vehicle headlamp 60 shown in FIG. 7, the entire light guide plate 21 has spherical aberration of the projection lens 61 for projecting the light exit surface 21b in the left-right direction. The lens is curved so as to correct the spherical aberration in accordance with the direction.

  In this embodiment, similarly to the sixth embodiment, in addition to the effect that the spherical aberration is corrected, the reflected light of the additional light source 13 is collected in the left-right direction at the curved portion of the light guide plate unit 21 and is applied to the projection lens 61. There is an effect that the incident efficiency is increased.

[Example 8]
FIG. 10 shows a configuration of an eighth embodiment of the vehicle headlamp according to the present invention.
In FIG. 10, the vehicle headlamp 90 has substantially the same configuration as that of the vehicle headlamp 40 shown in FIG. 5, and thus the same components are denoted by the same reference numerals and description thereof is omitted. The vehicle headlamp 90 has a different configuration only in that the additional light source 13 is disposed in a plane A that is perpendicular to the axis of the cylindrical lens 41b of the projection lens 41 and passes through the boundary portion with the convex lens 41a. ing.

According to the vehicle headlamp 90 having such a configuration, the vehicle headlamp 90 operates in the same manner as the vehicle headlamp 40 shown in FIG.
Further, the additional light source 13 is arranged on the optical axis of each convex lens 41 a of the projection lens 41. Therefore, after the light from each additional light source 13 is reflected by the surface of the light guide plate 21, it is condensed by the corresponding convex lens 41a. As a result, the light from each additional light source 13 is efficiently collected and the max luminous intensity is increased.

[Example 9]
FIG. 11 shows the configuration of the light guide plate unit in the ninth embodiment of the vehicle headlamp according to the present invention.
In FIG. 11, the vehicle headlamp is configured in the same manner as the vehicle headlamp shown in FIG. 3, and differs only in that a light guide plate unit 100 is provided instead of the light guide plate unit 30. ing.

Compared with the light guide plate unit 30 shown in FIG. 3, the light guide plate unit 100 is configured such that the reflection sheet 31 a can be retracted from the surface of the light guide plate 21 as indicated by an arrow B. Is supported to be swingable on the incident surface 21a side.
The reflection sheet 31a is configured to be retracted to a retracted position illustrated by a driving mechanism (not illustrated) corresponding to the DRL function.

According to the vehicle headlamp having such a configuration, in the light guide plate unit 100, at the time of normal use, that is, when used as a passing beam or the like, the reflection sheet 31 a is in a position in contact with the surface 21 b of the light guide plate 21. Therefore, the light guide plate 30 operates in the same manner as the light guide plate 30 shown in FIG.
On the other hand, when used as a DRL, the reflective sheet 31a is retracted from the surface of the light guide plate 21 to the retracted position shown in FIG. Thereby, the light incident on the surface of the light guide plate 21 from the additional light source 13 enters the light guide plate 21 over the entire surface of the light guide plate 21 and is reflected on the back surface of the light guide plate 21. The light is reflected by the sheet 26 and is emitted from the surface of the light guide plate 21 again.

The light reflected from the surface of the light guide plate 21 or emitted from the inner side is irradiated forward in the light irradiation direction through the projection lens to form a DRL light distribution pattern.
Thereby, the reflection at the projection lens side of the reflection sheet 31a or the housing holding the reflection sheet 31a in the light guide plate unit 30 becomes unnecessary.

  In the above-described embodiment, as for the vehicle headlamp, the light distribution characteristic for the passing beam is limited to the case of right-hand traffic, so as not to give illusion light to the oncoming vehicle on the left side toward the front of the vehicle. The cut-off pattern does not irradiate light above the horizontal line, but this is not limited to this, and in the case of left-hand traffic, the arrangement of the cut-off pattern is reversed left and right in the vehicle headlamp. The effect of will be obtained.

  In the embodiment described above, the LED 22 that is a plurality of point light sources is used as the light source. However, the present invention is not limited to this, and other point light sources such as a semiconductor laser element may be used. It is obvious that a linear light source may be used as long as the luminance control element 24 in the light guide plate 21 can define a desired luminance distribution on the light exit surface 21b.

  The vehicle headlamp according to the present invention is applicable not only to a headlamp but also to any vehicle headlamp including an auxiliary headlamp such as a fog lamp and a driving lamp.

  Thus, according to the present invention, a vehicle headlamp capable of irradiating two or more light distribution patterns such as a headlamp + DRL and a fog lamp + DRL is provided.

It is a schematic longitudinal cross-sectional view which shows the structure of 1st embodiment of the vehicle headlamp by this invention. It is a disassembled perspective view which expands and shows the light-guide plate unit in the vehicle headlamp of FIG. It is a schematic perspective view which shows the light-guide plate unit in 2nd embodiment of the vehicle headlamp by this invention. It is a ray tracing figure at the time of DRL use in the vehicle headlamp of FIG. It is (A) schematic cross-sectional view and (B) schematic longitudinal cross-sectional view which show the structure of 3rd embodiment of the vehicle headlamp by this invention. It is (A) schematic cross-sectional view and (B) schematic longitudinal cross-sectional view which show the structure of 4th embodiment of the vehicle headlamp by this invention. It is (A) schematic cross-sectional view and (B) schematic longitudinal cross-sectional view which show the structure of 5th embodiment of the vehicle headlamp by this invention. It is a schematic cross-sectional view showing the configuration of the sixth embodiment of the vehicle headlamp according to the present invention. It is a schematic cross-sectional view showing the configuration of the seventh embodiment of the vehicle headlamp according to the present invention. It is a schematic cross-sectional view which shows the structure of 8th embodiment of the vehicle headlamp by this invention. It is a schematic perspective view which shows the structure of the light-guide plate unit in 9th embodiment of the vehicle headlamp by this invention. It is a disassembled perspective view of the light source which shows a structure of an example of the conventional vehicle lamp. It is a fragmentary sectional view which shows the structure of the principal part in the lamp | ramp for vehicles of FIG. It is a schematic sectional drawing which shows the structure of an example of the headlamp which uses the conventional light-guide plate unit. It is a schematic sectional drawing which shows the modification of the headlamp of FIG.

Explanation of symbols

10, 40, 50, 60, 70, 80, 90 Vehicle headlamp 11, 41, 51, 61 Projection lens 12 Housing 20, 30, 100 Light guide plate unit 21 Light guide plate 21a Incident surface 21b Light exit surface 22 LED ( light source)
23 Housing 25, 25a, 25b Optical sheet 26 Reflective film

Claims (9)

A light guide plate made of a transparent material in a flat or wedge-shaped visible light region whose surface is a light emitting surface, a point-like or linear light source arranged facing one end face of the light guide plate, and the light guide plate A light guide plate unit composed of a brightness control member provided on the front surface and / or the back surface, a convex projection lens that focuses the emitted light from the light exit surface of the light guide plate and irradiates the light irradiation direction forward; In vehicle headlamps including
Comprising at least one additional light source disposed between the light guide plate unit and the projection lens or below the light guide plate unit;
The light from the additional light source is reflected by the light guide plate unit and irradiated forward through the projection lens in the light irradiation direction to form a second light distribution pattern different from the predetermined light distribution pattern. The vehicle headlamp is a feature.   The vehicle headlamp according to claim 1, wherein the light from the additional light source forms a light distribution pattern of a data imprinting light.   The light guide plate unit is arranged to be inclined with respect to the optical axis of the projection lens in order to align the direction of the maximum luminous intensity of the light emitted from the light guide plate with the optical axis of the projection lens. The vehicle headlamp according to claim 1 or 2.   The vehicle headlamp according to any one of claims 1 to 3, wherein at least a part of the projection lens is a cylindrical lens having an axis extending in a lateral direction. The projection lens is formed as a cylindrical lens whose both ends are formed as convex lenses and whose axis extends in the lateral direction in the region between them.
The vehicle headlamp according to any one of claims 1 to 3, wherein the additional light source is disposed in a plane perpendicular to the axis of the cylindrical lens and passing through a boundary portion with the convex lens.   The vehicle headlamp according to any one of claims 1 to 5, wherein a light emission surface of the light guide plate has a shape corresponding to a cut-off pattern.   The light guide plate includes a light guide portion that reduces luminance unevenness of light from the light source in areas adjacent to the light source side edge on the front and back surfaces of the light guide plate, and is adjacent to the light source side edge on the surface of the light guide plate. A reflective sheet or a light shielding sheet having a shape corresponding to the cut-off pattern and reflecting light from the surface of the light guide plate into the light guide plate, and the casing holding the reflective sheet or the light shielding sheet The vehicle headlamp according to any one of claims 1 to 5, wherein the projection lens side surface is a reflection surface for reflecting the light from the additional light source toward the projection lens. .   In a region adjacent to the light source side edge on the front and back surfaces of the light guide plate, the light guide unit includes a light guide portion that reduces luminance unevenness of light from the light source, and on the light source side edge of the surface of the light guide plate, A reflection sheet or a light shielding sheet having a shape corresponding to the cut-off pattern and reflecting light from the surface of the light guide plate into the light guide plate is configured to be retractable from the surface of the light guide plate. The vehicle headlamp according to any one of claims 1 to 5, wherein the vehicle headlamp is provided.   The vehicle headlamp according to any one of claims 1 to 8, wherein the light guide plate is curved so as to correspond to the aberration of the projection lens.

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