JP5879065B2 - Vehicle headlamp - Google Patents

Description

  The present invention relates to a vehicle headlamp.

  2. Description of the Related Art Conventionally, as a vehicle headlamp such as an automobile headlight, an LED using a light source is known. Particularly in recent years, with the improvement of the optical performance of LEDs, there are increasing applications of LEDs as light sources for vehicle headlamps.

  This type of vehicle headlamp generally includes an LED, a drive circuit that performs drive control of the LED, and a heat dissipation member that dissipates heat from the LED and the drive circuit. From the viewpoint of workability, it is provided to be exposed outside the lamp.

  Specifically, for example, in the vehicle headlamp described in Patent Document 1, as shown in FIG. 8, the LED 81 and the drive circuit 82 are unitized as a light source module 80 in a state where the LED 81 and the drive circuit 82 are mounted on a metal substrate 83. Of these, the drive circuit 82 is exposed outside the reflector 84 that covers the LED 81. The light source module 80 (metal substrate 83) is fixed on a pedestal 85 to which a heat radiating member (heat sink) (not shown) is attached so that heat can be transferred. Is dissipated from the heat dissipating member.

Japanese Patent No. 4523055

  However, the vehicular headlamp described in Patent Document 1 has a structure in which the LED 81 and the drive circuit 82 are both radiated through the metal substrate 83 on which both are mounted. Heat from the LED 81 is transmitted to the drive circuit 82 through the metal substrate 83. In other words, the LED 81 cannot be effectively radiated and the temperature of the drive circuit 82 is increased, so that the life and reliability of the drive circuit 82 may be reduced. Further, when a coating agent such as insulating grease is interposed between the metal substrate 83 and the pedestal 85 as a heat dissipation path, the thermal resistance between the metal substrate 83 and the pedestal 85 is equivalent to the amount of the coating agent. As a result, the heat from the LED 81 is more easily transmitted to the drive circuit 82.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the vehicle headlamp which can thermally radiate LED and a drive circuit effectively compared with the past.

In order to solve the above-mentioned problem, the invention described in claim 1
LED,
A drive circuit for controlling the drive of the LED;
A light source module configured to dissipate heat generated by the LEDs and the drive circuit, and a light source module,
A holder for holding the light source module;
In a vehicle headlamp comprising:
The LED and the drive circuit are each directly attached to the heat dissipation member,
The heat radiating member is configured integrally with a concave portion formed on the front surface so as to open forward, an extending portion extending forward from the bottom surface of the concave portion, and a heat radiating fin formed on the rear surface. ,
The LED is attached to the extension part,
The drive circuit is mounted in the recess;
The extension portion protrudes to the front side from the opening peripheral edge portion of the recess,
An insertion hole for inserting the extension portion is provided in the rear half of the holder.

The invention according to claim 2 is the vehicle headlamp according to claim 1,
A flange portion is provided on the opening peripheral edge of the recess,
At the rear end of the holder, a light source holding part for holding the light source module is formed in a substantially disc shape,
The light source module is held by the holder by engaging the flange portion and the light source holding portion .

The invention according to claim 3 is the vehicle headlamp according to claim 2 ,
The light source holding part is provided with a fitting part that is formed in a concave shape that opens rearward and that fits in the front-rear direction with the flange part,
A positioning mechanism for positioning the light source module in the circumferential direction with respect to the holder is provided on each of the outer peripheral edge of the flange portion and the inner peripheral surface of the fitting portion .

Invention of Claim 4 is the vehicle headlamp as described in any one of Claims 1-3,
The drive circuit is sealed with resin.
Invention of Claim 5 is the vehicle headlamp as described in any one of Claims 1-4,
One LED for forming a low beam is attached to the upper surface of the extension part, and another LED for forming a high beam is attached to the lower surface.

  According to the present invention, the LED and the drive circuit are directly attached to the heat dissipating members for dissipating these heat generations, so that they are dissipated through the metal substrate on which both the LED and the drive circuit are mounted. Unlike the conventional case, heat from the LED is not transmitted to the drive circuit through the metal substrate, and heat generated from the LED and the drive circuit can be directly transmitted to the heat dissipation member and dissipated from the heat dissipation member. Therefore, it is possible to effectively dissipate heat from the LED and the drive circuit as compared with the conventional case.

It is a perspective view of the vehicle headlamp in an embodiment. It is a disassembled perspective view of the vehicle headlamp in embodiment. It is a sectional side view of the vehicle headlamp in an embodiment. It is the perspective view which looked at the holder in embodiment from back. It is a figure for demonstrating the optical path in the vehicle headlamp in embodiment. It is a figure which shows the light distribution pattern formed on a virtual screen with the vehicle headlamp in embodiment. It is sectional drawing which shows the state in which the vehicle headlamp in embodiment was accommodated in the housing. It is a sectional side view of the conventional vehicle headlamp.

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

FIG. 1 is a perspective view of a vehicle headlamp 1 according to the present embodiment, FIG. 2 is an exploded perspective view of the vehicle headlamp 1, and FIG. 3 is a side sectional view of the vehicle headlamp 1. FIG. 4 is a perspective view of a holder 3 (described later) included in the vehicle headlamp 1 as seen from the rear.
In the following description, unless otherwise specified, the descriptions of “front”, “rear”, “left”, “right”, “upper”, and “lower” refer to the direction viewed from the vehicle headlamp 1, It shall be used corresponding to the description in the drawing.

  As shown in FIGS. 1 to 3, a vehicle headlamp 1 is a projector-type lamp that is mounted on a front portion of a vehicle (not shown) and forms a predetermined light distribution pattern (low beam and high beam) in front of the vehicle. , A light source module 2, a holder 3, a shade 4, and a projection lens 5.

Among these, the light source module 2 supports the first LED 22 and the second LED 23 which are light sources, and includes a metal module main body 21.
The module main body 21 is formed in a circular shape when viewed from the front, and has a concave portion 21a formed on the front surface and an extending portion 21b extending forward from the center of the bottom surface of the concave portion 21a.
The first LED 22 mounted on the substrate 221 is directly attached to the upper surface of the extending portion 21b with the light emitting surface facing upward. The front half of the lower surface of the extending portion 21b is a tapered surface that is inclined upward and forward at an inclination angle of 15 ° with respect to the front-rear direction. The second LED 23 mounted on is directly attached. Therefore, the light emitting surface of the second LED 23 is oriented obliquely downward and forward along the tapered surface. Further, the second LED 23 is disposed in front of the first LED 22 by a predetermined distance. The predetermined distance is preferably within a range of 5 to 30 mm, and more preferably about 20 mm.

  In the concave portion 21a of the module body 21, drive circuits 24 and 24 for controlling the driving of the first LED 22 and the second LED 23 based on signals from the outside are divided into two portions so as to sandwich the extending portion 21b vertically. It is directly attached in the recess 21a. The drive circuits 24, 24 are sealed with a resin R filled in the recess 21a. The resin R is made of, for example, a silicon-based resin material, and enhances heat dissipation of the drive circuits 24 and 24 and waterproofs the drive circuits 24 and 24. In addition, a power supply and control cable 241 is wired in the drive circuits 24, 24, and the cable 241 is led out from the bottom bottom of the recess 21a.

  On the rear surface of the module main body 21, a plurality of radiating fins 25,. The heat radiation fins 25,... Dissipate heat generated by the first LED 22, the second LED 23, and the drive circuits 24, 24. Therefore, the module main body 21 having the heat radiation fins 25,... Is a heat radiation member for dissipating heat generated by the first LED 22, the second LED 23, and the drive circuits 24, 24. Further, the module main body 21 is integrally formed as a single member with a metal material (for example, an aluminum alloy) excellent in heat conduction from the extending portion 21b to the concave portion 21a and the radiation fins 25,. The heat from the two LEDs 23 and the drive circuits 24, 24 is transmitted to the heat radiation fins 25,.

  An opening peripheral portion of the recess 21 a of the module body 21 is a flange portion 21 c that fits with the holder 3. The flange portion 21c is formed in a circular shape orthogonal to the front-rear direction, and three notches 21d,... Arranged at unequal pitches are formed on the outer peripheral edge thereof. The notches 21d,... Engage with protrusions 32b, which will be described later, formed on the holder 3 so that the module main body 21 (light source module 2) is placed in the circumferential direction (the front-rear direction is the central axis). Position in the direction of rotation).

The holder 3 holds the light source module 2 and the projection lens 5, and is formed in a shape in which a light source holding part 32 and a lens holding part 33 are provided at the rear end and front end of the holder main part 31.
Among these, the light source holding part 32 is a part that detachably holds the light source module 2, and is formed in a substantially disc shape and has a concave fitting part 32 a that opens rearward. The fitting portion 32 a is a portion for positioning the light source module 2 by fitting in the front-rear direction with the flange portion 21 c of the module main body 21. Therefore, the light source module 2 is attached to the light source holding part 32 (holder 3) by fitting the flange part 21c to the fitting part 32a from the rear, and the flange part 21c is moved from the state fitted to the fitting part 32a. By detaching backward, the light source holder 32 (holder 3) is detached. That is, the light source module 2 is detachable from the light source holding part 32 in the front-rear direction.
4, three protrusions 32b,... Are formed on the inner peripheral surface (inner peripheral edge) of the light source holding portion 32 at positions corresponding to the notches 21d,. The flange portion 21c is fitted into the fitting portion 32a so that the three protrusions 32b,... Individually engage with the three notches 21d,. Correctly positioned. Further, on the inner peripheral surface of the light source holding portion 32, three centering protrusions 32c,... That contact the outer peripheral surface of the flange portion 21c and center the flange portion 21c are different from the three protrusions 32b,. It is formed at a circumferential position.

As shown in FIGS. 1 to 3, the holder main part 31 has an insertion hole 31 a into which the extension part 21 b of the module body 21 is inserted in the rear half part. The insertion hole 31a opens in the center of the bottom surface of the fitting portion 32a, and is drilled along the front-rear direction from the opening, so that the extension portion 21b of the module body 21 is inserted from the rear. Yes. More specifically, when the flange portion 21c is fitted to the fitting portion 32a and the light source module 2 is attached to the holder 3, the extension portion 21b is inserted into the insertion hole 31a, and the first LED 22 and the second LED 23 are inserted. Is positioned with respect to the optical system of the vehicle headlamp 1 (a first reflecting surface 311, a second reflecting surface 312 and a third reflecting surface 313, and a projection lens 5 described later).
The upper plate portion of the insertion hole 31a is formed in a substantially half dome shape that opens forward, and is formed so as to cover the top of the first LED 22 on the upper surface of the extension portion 21b inserted into the insertion hole 31a. The lower surface (inner surface) is the first reflecting surface 311. The first reflecting surface 311 is a free-form surface based on a spheroidal surface, and includes a first focal point located near the first LED 22 and a second focal point located near the front edge of the shade 4 disposed in front. have. Of these, the second focal point may be a focal line that is positioned forward as the distance from the center of the first reflecting surface 311 in the left-right direction increases.

The center part from the front-rear direction of the holder main part 31 to the front half part is formed in a curved concave shape that opens obliquely upward and forward, and the second reflection surface 312 and the third reflection surface 313 are formed on the upper surface (inner surface). Has been.
Among these, the 2nd reflective surface 312 is formed in the front-back direction center part of the holder main part 31 so that the downward direction of the 2nd LED23 of the extension part 21b lower surface may be covered. The second reflecting surface 312 is a free-form surface based on a spheroid surface, and a first focal point located in the vicinity of the second LED 23 and a first diagonally located front forward of the front edge of the shade 4 disposed in front. With two focal points. The distance from the first focal point of the second reflecting surface 312 to the second focal point is shorter than the distance from the first focal point to the second focal point of the first reflecting surface 311.
On the other hand, the third reflecting surface 313 is formed in the front half of the holder main portion 31 and continues to the front of the second reflecting surface 312. The third reflecting surface 313 is a free-form surface based on a rotating two-leaf hyperboloid, and has a first focus located in the vicinity of the second LED 23 and a second focus located obliquely below and behind the first focus. doing.

  The lens holding portion 33 is a holding frame that holds the projection lens 5 and is formed in an annular shape having a central axis along the front-rear direction.

  The shade 4 is a substantially flat light-shielding member, and is attached to the center portion in the front-rear direction of the holder main portion 31 with the lower surface in contact with the front end of the upper surface of the extending portion 21b. More specifically, the shade 4 has engagement protrusions 4a and 4a at both left and right ends, and the engagement protrusions 4a and 4a are formed in engagement recesses 31b and 31b formed on the left and right side surfaces of the holder main portion 31, respectively. It is attached to the holder main part 31 by engaging from above. As for this shade 4, the front half part protrudes ahead rather than the front end of the extension part 21b, and the 2nd focus of the 1st reflective surface 311 is located in the front-end edge vicinity as mentioned above. Therefore, a part of the light emitted from the first LED 22 and reflected by the first reflecting surface 311 is shielded by the shade 4, and a cut-off line C of the low beam PL is formed as will be described later (FIG. 6A). reference). Further, the upper surface of the shade 4 is a mirror surface that has been subjected to aluminum vapor deposition or the like, and the light reflected by the first reflecting surface 311 and incident on the upper surface is directed toward the middle lens portion 52 of the projection lens 5 described later. To reflect (see FIG. 5A).

The projection lens 5 is attached to the lens holding portion 33 so that the optical axis Ax extends in the front-rear direction and the first LED 22 and the shade 4 are positioned behind the optical axis Ax. The projection lens 5 is a bifocal lens, and has an upper lens portion 51, a middle lens portion 52, and a lower lens portion 53 that are integrally molded.
The upper lens unit 51 is an aspherical convex lens, and its rear focal point is located in the vicinity of the second focal point of the second reflecting surface 312.
The middle lens unit 52 is an aspherical convex lens, and its rear focal point is located near the second focal point of the first reflecting surface 311. The middle lens unit 52 has an exit surface (front surface) divided in a Fresnel cut shape in the left-right direction.
The lower lens unit 53 is an aspherical convex lens, and its rear focal point is located near the second focal point of the third reflecting surface 313.

Next, the operation of the vehicle headlamp 1 will be described.
FIG. 5 is a diagram for explaining an optical path in the vehicle headlamp 1, and FIG. 6 is a diagram showing a light distribution pattern formed on the virtual screen in front of the vehicle by the vehicle headlamp 1. is there.

  In the vehicle headlamp 1, as shown in FIG. 5A, when the first LED 22 is turned on by the drive circuits 24 and 24 and the second LED 23 is turned off, the light is emitted from the first LED 22. The reflected light is reflected forward by the first reflecting surface 311 and is inverted and projected from the middle lens portion 52 of the projection lens 5 to the front of the vehicle. At this time, a part of the light incident on the lower part of the middle lens unit 52 is shielded by the shade 4, so that the irradiation light above the cut-off line C near the horizontal line H as shown in FIG. A low beam PL in which is blocked is formed.

  On the other hand, as shown in FIG. 5B, when the first LED 22 is turned off and the second LED 23 is turned on by the drive circuits 24 and 24, the second of the light emitted from the second LED 23. The light incident on the reflecting surface 312 is reflected forward by the second reflecting surface 312 and is reversely projected from the upper lens portion 51 of the projection lens 5 to the front of the vehicle. At the same time, the light emitted from the second LED 23 and incident on the third reflecting surface 313 is reflected forward by the third reflecting surface 313 and invertedly projected forward from the lower lens portion 53 of the projection lens 5 to the vehicle front. Is done. At this time, the light incident on the upper lens unit 51 and the lower lens unit 53 is irradiated to the front of the vehicle through the upper lens unit 51 and the lower lens unit 53 without being blocked by the shade 4, so that FIG. ), A high beam PH having an irradiation region above the horizontal line H is formed. Here, the irradiation light from the upper lens unit 51 is irradiated over the entire high beam PH, and the irradiation light from the lower lens unit 53 is irradiated to a high intensity region near the center of the high beam PH. Yes.

  As described above, according to the vehicle headlamp 1, the first LED 22, the second LED 23, and the drive circuits 24, 24 are directly attached to the module main body 21 having the radiation fins 25,. Therefore, unlike the conventional case in which the LED and the drive circuit are both mounted to dissipate heat through the metal substrate, heat from the LED is not transmitted to the drive circuit through the metal substrate, and the first LED 22, The heat generated by the second LED 23 and the drive circuits 24, 24 can be directly transmitted to the module body 21 to be dissipated from the module body 21 (radiation fins 25,...). Therefore, the first LED 22, the second LED 23, and the drive circuits 24, 24 can be radiated effectively compared to the conventional case.

  Moreover, since the drive circuits 24 and 24 are sealed with resin, the heat dissipation of the drive circuits 24 and 24 can be enhanced while waterproofing the drive circuits 24 and 24.

  The embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention.

  For example, in the above embodiment, the vehicle headlamp 1 is a projector-type lamp, but the vehicle headlamp 1 may be a reflector-type or direct projection-type lamp.

  In addition, the first LED 22 is described as being “directly” attached to the extension portion 21b of the module body 21, but strictly speaking, the substrate 221 is interposed between the first LED 22 and the extension portion 21b. ing. However, since the substrate 221 is a minimum component necessary for light emission (heat generation) of the first LED 22 and functions integrally with the first LED 22, the first LED 22 is “directly” on the extending portion 21 b. Can be considered attached. The same applies to the second LED 23.

  The first LED 22 is arranged with the light emitting surface facing upward, but the light emitting surface of the first LED 22 is inclined obliquely backward within a range of 20 ° or less with respect to the front-rear direction. You may let them. Thus, the luminous flux utilization factor of the first LED 22 can be improved by inclining the light emitting surface of the first LED 22 within the above range to face the first reflecting surface 311.

  In addition, the second LED 23 is arranged in a state where the light emitting surface is inclined at an inclination angle of 15 ° with respect to the front-rear direction. The inclination angle of the light emitting surface of the second LED 23 is 10 ° to 30 °. If it is in the range. As described above, the light emitted from the second LED 23 and reflected by the second reflecting surface 312 and the third reflecting surface 313 is inclined by tilting the light emitting surface of the second LED 23 at an inclination angle within the above range. It can be made easier to direct toward the portion 51 and the lower lens portion 53.

  In addition, the first reflecting surface 311, the second reflecting surface 312 and the third reflecting surface 313 are formed on the holder 3, but the first reflecting surface 311, the second reflecting surface 312 and the third reflecting surface 313 are formed. And the holder 3 may be configured separately. Further, the holder 3 and the shade 4 may be configured integrally.

  Further, as shown in FIG. 7, when the vehicle headlamp 1 is housed in the housing 6, it is preferable that the radiation fins 25,... Be exposed rearward through the flexible member 7. . With such a configuration, it is possible to improve the heat radiation performance of the heat radiation fins 25,.

1 Vehicle headlamp 2 Light source module 21 Module body (heat dissipation member)
21a Concave part 21b Extension part 21c Flange part 21d Notch 22 First LED
23 Second LED
24 drive circuit 25 radiation fin 3 holder 31 holder main part 311 first reflecting surface 312 second reflecting surface 313 third reflecting surface 31a insertion hole 32 light source holding part 32a fitting part 32b protrusion 33 lens holding part 4 shade 5 projection lens 51 Upper lens part 52 Middle lens part 53 Lower lens part Ax Optical axis 6 Housing 7 Flexible member C Cut-off line PL Low beam PH High beam R Resin

Claims (5)

LED,
A drive circuit for controlling the drive of the LED;
A light source module configured to dissipate heat generated by the LEDs and the drive circuit, and a light source module,
A holder for holding the light source module;
In a vehicle headlamp comprising:
The LED and the drive circuit are each directly attached to the heat dissipation member,
The heat radiating member is configured integrally with a concave portion formed on the front surface so as to open forward, an extending portion extending forward from the bottom surface of the concave portion, and a heat radiating fin formed on the rear surface. ,
The LED is attached to the extension part,
The drive circuit is mounted in the recess;
The extension portion protrudes to the front side from the opening peripheral edge portion of the recess,
A vehicular headlamp, wherein an insertion hole for inserting the extending portion is provided in a rear half portion of the holder. A flange portion is provided on the opening peripheral edge of the recess,
At the rear end of the holder, a light source holding part for holding the light source module is formed in a substantially disc shape,
The vehicle headlamp according to claim 1, wherein the light source module is held by the holder through engagement of the flange portion and the light source holding portion. The light source holding part is provided with a fitting part that is formed in a concave shape that opens rearward and that fits in the front-rear direction with the flange part,
The positioning mechanism for positioning the said light source module with respect to the said holder in the circumferential direction is provided in the outer periphery of the said flange part, and the internal peripheral surface of the said fitting part, respectively. 2. A vehicle headlamp according to 2.   The vehicle headlamp according to any one of claims 1 to 3, wherein the drive circuit is sealed with resin.   The one LED for forming a low beam is attached to the upper surface of the extension part, and the other LED for forming a high beam is attached to the lower surface. The vehicle headlamp according to any one of 4.

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