JP2013054902A - Vehicle headlamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to illuminate the upper part than a horizontal line orthogonal to an optical axis.SOLUTION: The vehicle headlamp 1 is provided with: a bulb 50 having a light source 52; a reflecting surface 11 which has a first focal point F1 at the light source 52 or in the vicinity of it, has a second focal point F2 in front of the first focal point F1, and reflects light emitted from the light source 52 to the front; a projection lens 60 which is arranged in front of the bulb 50, has a rear side focal point F3 at the second focal point F2 or in the vicinity of it, and has an optical axis Ax extending to the front from the focal point F3; and a shutter 80 which is arranged between the projection lens 60 and the bulb 50, has an upper edge 81 extending to right and left at the rear side focal point F3 or in the vicinity of it, and shields a part of light reflected by the reflecting surface 11. The width in right and left direction of the shutter 80 and its upper edge 81 is shorter than the effective diameter D of the projection lens 60.

Description

  The present invention relates to a vehicle headlamp.

  In conventional projector-type headlamps, the projection lens is placed in front of the ellipsoidal reflector, the upper edge of the shutter is located near the rear focal point of the projection lens, and the bulb filament is the first focal point of the ellipsoidal reflector. The second focal point of the ellipsoidal reflector is disposed in the vicinity of the rear focal point of the projection lens (see, for example, Patent Document 1). The light emitted from the bulb filament is reflected forward by the ellipsoidal reflector, a part of the reflected light is blocked by the shutter, and the light passing forward on the upper edge of the shutter is projected forward by the projection lens. The Since the upper edge of the shutter is located near the rear focal point of the projection lens, the shape of the upper edge of the shutter is inverted and projected forward as a cut-off line, and the light distribution for the low beam whose cut-off line is the upper limit of the bright part is It is formed. The cut-off line is formed along a horizontal line orthogonal to the optical axis on a virtual screen facing the vehicle. Therefore, no light is irradiated above the horizontal line orthogonal to the optical axis, and the area above the horizontal line becomes a dark part, thereby preventing the driver of the oncoming vehicle from being dazzled.

JP 2008-1306 A

  However, since the conventional projector type headlamp does not irradiate light above the horizontal line orthogonal to the optical axis, it cannot illuminate the signboard or sign on the front side of the vehicle. In particular, in the case of a motorcycle, since the motorcycle is tilted to the left or right during cornering, the cut-off line formed by the conventional projector-type headlamp is inclined with respect to the horizontal line. Therefore, the traveling direction is not illuminated by the projector headlamp. There is a technique that uses an additional lamp unit to illuminate the traveling direction (see, for example, Patent Document 1), but the cost increases by the additional lamp unit.

  Therefore, the problem to be solved by the present invention is to enable illumination above the horizontal line orthogonal to the optical axis.

The vehicle headlamp according to the present invention for solving the above problems is
A bulb having a light source;
A reflective surface that has a first focal point at or near the light emitting source of the bulb, has a second focal point in front of the first focal point, and reflects light emitted from the light emitting source forward;
A projection lens disposed in front of the bulb, having a rear focal point at or near the second focal point, and having an optical axis extending forward from the rear focal point;
A shutter disposed between the projection lens and the bulb, having an upper edge extending left and right at or near the rear focal point of the projection lens, and blocking a part of the light reflected by the reflecting surface; With
The left and right widths of the shutter and its upper edge are shorter than the effective diameter of the projection lens,
The projection lens irradiates light reflected by the reflecting surface and passing forward over the upper edge of the shutter below a horizontal line perpendicular to the optical axis;
The projection lens irradiates light that is reflected by the reflecting surface and passes forward on both left and right sides of the shutter above a horizontal line that is orthogonal to the optical axis.

  Preferably, the projection lens includes: light reflected by the reflecting surface and passing forward through the left side of the shutter; and light reflected by the reflecting surface and passing forward through the right side of the shutter. One is irradiated above the horizontal line orthogonal to the optical axis and to the right of the vertical line orthogonal to the optical axis, and the other is irradiated above the horizontal line orthogonal to the optical axis and orthogonal to the optical axis. Irradiate to the left of the vertical line.

  Preferably, the optical axis passes through the center of the upper edge of the shutter in the left-right direction.

Preferably, the bulb includes an H4 bulb having a glass tube in which the light emitting source is enclosed, and a hood which is enclosed in the glass tube and is provided so as to surround the lower side of the light emitting source. And
The bulb is arranged so that the hood is symmetrical with respect to the optical axis in front view.

According to the present invention, since the width of the shutter and its upper edge in the left-right direction is shorter than the effective diameter of the projection lens, the light reflected by the reflecting surface and passing through the left and right sides of the shutter in front of the optical axis is projected by the projection lens. It irradiates above the horizontal line orthogonal to. Therefore, the upper area in front of the vehicle is illuminated. Therefore, when the vehicle is a motorcycle, even if the motorcycle is tilted left and right, the traveling direction is illuminated, which can contribute to safe driving.
Rather than the light that has passed under the immediate vicinity of the focal point of the projection lens, the light that has passed through the left and right sides of the shutter is irradiated above the horizontal line orthogonal to the optical axis by the projection lens. Therefore, the bright part formed by the light is not too bright and does not become a dazzling factor for the driver of the oncoming vehicle.
Since the vehicle front lamp illuminates the upper area in front of the vehicle, no additional lamp is required and the cost is not increased.

1 is a front view of a vehicle headlamp according to an embodiment of the present invention. It is sectional drawing which showed the cut surface along II-II seeing in the arrow direction. It is a front view of the vehicle headlamp which concerns on a modification. It is a front view of the vehicle headlamp which concerns on a modification. It is drawing which showed the light distribution characteristic of the vehicle headlamp which concerns on the same embodiment. It is the figure which showed the light distribution characteristic when a motorcycle inclines to the left. It is drawing which showed the light distribution characteristic of the vehicle headlamp which concerns on a modification.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. However, the embodiments described below are given various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

  In the following description, “up”, “down”, “front”, “back”, “left”, and “right” are “up” and “down” of vehicles equipped with vehicle headlamps, respectively. , “Front”, “back”, “left”, “right”. Accordingly, when looking from the rear to the front of the vehicle (from the viewpoint of the driver), “left” and “right” are determined.

  FIG. 1 is a front view of a vehicle headlamp 1. FIG. 2 is a cross-sectional view showing the surface along II-II shown in FIG. 1 as seen in the direction of the arrow. The cross section shown in FIG. 2 is a cross section along a vertical plane that passes through the optical axis Ax of the vehicle headlamp 1 and is orthogonal to the horizontal plane.

  The vehicle headlamp 1 is a projector-type headlamp, and is particularly attached to the front surface of a motorcycle. The vehicular headlamp 1 forms a light distribution for a passing beam in front of the vehicle, and the vehicular headlamp 1 is used in combination with a lamp that forms a traveling beam light distribution. The light distribution for the traveling beam and the light distribution for the passing beam are switched.

  As shown in FIG. 2, the vehicle headlamp 1 includes a reflector 10, a standing wall 40, a bulb 50, a projection lens 60, a lens holder 70, a shutter 80, and the like.

  The bulb 50 is a halogen bulb, an incandescent bulb, a discharge lamp (for example, a high-intensity discharge lamp (HID), a high-pressure metal vapor discharge lamp, etc.) or other bulbs. The bulb 50 includes a glass tube 51, a light emission source 52, and the like, and the light emission source 52 is enclosed in a cylindrical glass tube 51. The light emission source 52 is a filament or a discharge part.

  The reflector 10 and the standing wall 40 are integrally molded to constitute an integrally molded product including the reflector 10 and the standing wall 40.

  The reflector 10 is provided in a bowl shape so as to surround the top, bottom, left, right, and back of the light emission source 52 of the bulb 50 and is opened forward. The reflector 10 is an ellipsoidal reflector, and a reflecting surface 11 formed in an ellipsoidal concave shape is formed on the front inner surface of the reflector 10. The reflecting surface 11 is a spheroidal surface having an optical axis Ax extending in the front-rear direction as a rotation axis, a flat elliptic surface obtained by crushing the spheroidal surface up and down, or a free curved surface based on these. For example, the reflecting surface 11 is a free-form surface based on a spheroid with the optical axis Ax as a rotation axis, and is formed such that its eccentricity gradually increases from a vertical section toward a horizontal section. . Note that the reflecting surface 11 may be a compound ellipsoid obtained by combining different ellipsoids in the region above and below the optical axis Ax.

  Since the reflecting surface 11 is formed in an elliptical concave shape, the reflecting surface 11 has a first focal point F1, a second focal point F2, and an optical axis. The first focus F1 is set in front of the rear vertex of the reflecting surface 11, the second focus F2 is set in front of the first focus F1, and the optical axis passing through the first focus F1 and the second focus F2 is set. The The optical axis of the reflecting surface 11 coincides with the optical axis Ax of the vehicle headlamp 1.

  A valve 50 is attached to the reflector 10. Specifically, the mounting hole 12 is formed in the rear apex portion of the reflector 10 so as to penetrate back and forth, and the glass tube 51 of the bulb 50 is inserted into the mounting hole 12 from the back of the reflector 10, and the glass tube 51 is It protrudes to the inside of the reflector 10 and extends in the front-rear direction. The center line of the glass tube 51 is parallel to the optical axis Ax, and preferably coincides with the optical axis Ax. A light emission source 52 of the bulb 50 is disposed on the first focal point F1 of the reflecting surface 11 or in the vicinity thereof.

  The reflecting surface 11 reflects light emitted from the light emission source 52 of the bulb 50 forward. Since the light source 52 of the bulb 50 is disposed at or near the first focal point F1 of the reflecting surface 11, the light emitted from the light source 52 of the bulb 50 and reflected by the reflecting surface 11 is condensed on the second focal point F2. Is done.

  When the bulb 50 is a double filament type H4 bulb, as shown in FIG. 1, a hood 53 is enclosed in a glass tube 51, and the hood 53 is provided so as to surround the lower side of the light emission source 52. Light directed downward from the source 52 is blocked by the hood 53. When the hood 53 is viewed from the front, the shape of the hood 53 is a sector shape with an obtuse angle (for example, 165 °), one of the two radii sandwiching the center angle is horizontal, and the other radius is in the radially outward direction. Inclined down. The light emission source 52 is a filament for passing between two filaments. As shown in FIG. 3, the bulb 50 is attached to the reflector 10 so as to rotate the arrangement position of the bulb 50 about the optical axis Ax, and the hood 53 is viewed from the front, and the middle angle of the hood 53 is the upper end. The two radii sandwiching the central angle may be inclined downward in the radial direction, and the hood 53 may be symmetrical with respect to the optical axis Ax.

  As shown in FIG. 2, a standing wall 40 is connected to the front end portion of the reflector 10. The standing wall 40 extends forward from the front end portion of the reflector 10. The upright wall 40 is provided in a cylindrical shape so as to surround the top, bottom, left and right of the area in front of the valve 50.

  A projection lens 60 is disposed in front of the reflector 10, the standing wall 40 and the bulb 50. The projection lens 60 is attached to the inside of the lens holder 70, and the lens holder 70 is attached to the front end portion of the standing wall 40. The projection lens 60 is a convex lens. The projection lens 60 has a rear focal point F3 and an optical axis extending forward and backward through the rear focal point F3. The optical axis of the projection lens 60 coincides with the optical axis Ax as a lamp. The rear focal point F3 of the projection lens 60 is located at or near the second focal point F2 of the reflecting surface 11.

  A shutter 80 is disposed between the projection lens 60 and the bulb 50 to block a part of the light reflected by the reflecting surface 11. The shutter 80 is disposed below the optical axis Ax. As shown in FIG. 1, leg portions 82 are provided at the lower portions of the left and right ends of the shutter 80, and the shutter portion 80 is fixed to the standing wall 40 by connecting the leg portions 82 to the standing wall 40.

  The shutter 80 has an upper edge 81 extending in the left-right direction. As shown in FIG. 2, the upper edge 81 of the shutter 80 is located at or near the focal points F2, F3. As shown in FIG. 1, the horizontal width of the shutter 80 and its upper edge 81 is shorter than the effective diameter D (particularly the effective diameter in the horizontal direction) of the projection lens 60, and the optical axis Ax is the upper edge 81 of the shutter 80. It passes through the center in the left-right direction. Of the upper edge 81 of the shutter 80, the central portion 81a is substantially horizontal, and the left and right sides 81b of the central portion 81a are inclined downward toward the side. As shown in FIG. 4, the entire upper edge 81 of the shutter 80 may be a horizontal surface extending left and right.

Next, the progress of light emitted from the light emission source 52 of the bulb 50 will be described.
When the light source 52 of the bulb 50 is turned on, the light traveling from the light source 52 toward the reflecting surface 11 is reflected forward by the reflecting surface 11, and the reflected light is collected by the reflecting surface 11 at the focal points F2 and F3. Part of the light collected at the focal points F2 and F3 passes forward on the upper edge 81 of the shutter 80, and the light is projected forward by the projection lens 60. A part of the light condensed at the focal points F2 and F3 is shielded by the shutter 80. Further, a part of the light reflected by the reflecting surface 11 is not condensed at the focal points F2 and F3 or in the vicinity thereof, and passes through the left and right sides of the shutter 80 (region A shown in FIG. 1) forward. Projected forward by the projection lens 60.

  With reference to FIG. 5, the light distribution characteristic of the vehicle headlamp 1 will be described. FIG. 5 shows a light distribution pattern formed on a virtual screen facing the vehicle at a predetermined distance forward from the vehicle headlamp 1. In FIG. 5, when the motorcycle stands upright, the intersection of the horizontal plane passing through the optical axis Ax of the vehicle headlamp 1 and the virtual screen is shown as HH line, and the vertical plane passing through the optical axis Ax and the virtual screen Are shown as VV lines, and the intersection of the HH line and the VV line is the intersection of the optical axis Ax of the vehicular headlamp 1 and the virtual screen. The optical axis Ax is orthogonal to the HH line and the VV line.

  When light traveling from the light emitting source 52 toward the reflecting surface 11 is reflected by the reflecting surface 11, a part of the reflected light is shielded by the shutter 80 in the vicinity of the focal points F2 and F3. Therefore, as shown in FIG. 5, the light reflected by the reflecting surface 11 and passing over the upper edge 81 of the shutter 80 is irradiated below the HH line by the projection lens 60, and the bright part B1 is in front of the vehicle. Are formed below the HH line of the virtual screen. Further, since the image of the upper edge 81 of the shutter 80 viewed from the rear is inverted in the vertical and horizontal directions by the projection lens 60 and projected forward, the bright and dark boundary that divides the bright part B1 and the dark part above it. A line (cut-off line) L1 is formed on the virtual screen. Since the central portion 81a of the upper edge 81 of the shutter 80 is a horizontal surface located at or near the focal points F2, F3, the light / dark boundary line L1 is a straight line along the line HH.

  Since part of the light reflected by the reflecting surface 11 passes forward on both the left and right sides of the shutter 80 below the focal point F3, the light is mainly irradiated above the HH line by the projection lens 60. , Bright portions B2 and B3 are formed on the HH line of the virtual screen. Here, the light passing forward on the left side of the shutter 80 is mainly irradiated on the HH line and to the right of the VV line, and passes forward on the right side of the shutter 80. The light is mainly irradiated on the HH line and to the left of the VV line. This is because the image of the focal plane (the plane passing through the focal point F3 and orthogonal to the optical axis Ax) is projected upside down and left and right by the projection lens 60 and projected. It should be noted that the left side of the shutter 80 is moved forward by appropriately changing the direction, curvature, etc. of a part of the reflecting surface 11, a part of the rear side incident surface of the projection lens 60, or a part of the front side incident surface of the projection lens 60. Is mainly irradiated on the left of the V-V line on the H-H line, and the light passing in front of the right side of the shutter 80 is mainly the H-H line. May be irradiated to the right of the VV line.

  The light that contributes to the formation of the bright portions B2 and B3 passes forward on the left and right sides of the shutter 80 at a position away from the focal point F3, and does not pass near the focal point F3. Therefore, the bright portions B2 and B3 are blurred bright portions, and the light / dark boundary line L1 is not unclear.

  Of the light reflected by the reflecting surface 11, the luminous flux passing forward on the upper edge 81 of the shutter 80 is larger than the luminous flux passing forward on both the left and right sides of the shutter 80. Therefore, the bright portions B2 and B3 are not as bright as the bright portion B1, and the light / dark boundary line L1 is not obscured.

  As shown in FIG. 3, if the valve 50 is mounted so that the hood 53 of the valve 50 is symmetrical, the bright portions B2 and B3 have equal brightness.

According to the above embodiment, the following effects can be obtained.
(1) If the motorcycle is upright, the bright parts B2 and B3 are formed on the HH line, so that a signboard, a sign and the like on the front of the motorcycle can be illuminated.
(2) If the motorcycle is cornered and tilted to the left, the road surface in the traveling direction is illuminated by the bright part B2 (see FIG. 6). If the motorcycle is tilted to the right, the bright part B3 The road surface can be illuminated. Therefore, the visibility in the traveling direction is improved, which can contribute to safe driving.
(3) Since the bright parts B2 and B3 are not as bright as the bright part B1, the driver of the oncoming vehicle is not dazzled by the bright parts B2 and B3.
(4) Since the bright parts B1, B2, B3 can be formed in front of the motorcycle by one bulb 50, no additional lamp unit is required. For this reason, the cost is not increased.

  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. Hereinafter, some modifications will be described. The following modifications may be combined as much as possible.

[Modification 1]
As shown in FIG. 7, the light projected by the projection lens 60 after passing through the left and right sides of the shutter 80 is not divided into the left and right sides of the VV line, but the entire bright portion on the HH line. B4 may be formed. That is, the light passing forward on the left side of the shutter 80 is irradiated on the HH line around the VV line by the projection lens 60, and the light passing forward on the right side of the shutter 80 is The projection lens 60 may irradiate the HH line around the VV line. Such a bright portion B4 is formed by appropriately changing the orientation or curvature of a part of the reflecting surface 11, a part of the rear side incident surface of the projection lens 60, or a part of the front side incident surface of the projection lens 60. It is feasible.

[Modification 2]
Of the upper edge 81 of the shutter 80 (the central portion 81a of the upper edge 81 in the case of FIG. 1 and the entire upper edge 81 in the case of FIG. 4), the portion on the right side of the optical axis Ax and the left side of the optical axis Ax. The part may be a step. Then, the cut-off line will also be different on the left and right.

[Modification 3]
Instead of the shutter 80 being fixed to the standing wall 40 or the like, the shutter 80 may be tilted forward or backward from the position described above by an actuator, or may be moved downward from the position described above. When the shutter 80 is moved to the above position by the actuator, a light distribution for the passing beam is formed, and when the shutter 80 is retracted from the above position by the actuator, a light distribution for the traveling beam is formed.

[Modification 4]
The vehicle headlamp 1 may be for an automobile.

DESCRIPTION OF SYMBOLS 1 Vehicle headlamp 10 Reflector 11 Reflecting surface 50 Bulb 51 Glass tube 52 Light source 53 Hood 60 Projection lens 80 Shutter 81 Upper edge F1, F2, F3 Focus Ax Optical axis

Claims (4)

A bulb having a light source;
A reflective surface that has a first focal point at or near the light emitting source of the bulb, has a second focal point in front of the first focal point, and reflects light emitted from the light emitting source forward;
A projection lens disposed in front of the bulb, having a rear focal point at or near the second focal point, and having an optical axis extending forward from the rear focal point;
A shutter disposed between the projection lens and the bulb, having an upper edge extending left and right at or near the rear focal point of the projection lens, and blocking a part of the light reflected by the reflecting surface; With
The left and right widths of the shutter and its upper edge are shorter than the effective diameter of the projection lens,
The projection lens irradiates light reflected by the reflecting surface and passing forward over the upper edge of the shutter below a horizontal line perpendicular to the optical axis;
The vehicular headlamp characterized in that the projection lens irradiates light that is reflected by the reflecting surface and passes forwardly on both left and right sides of the shutter above a horizontal line orthogonal to the optical axis.   The projection lens receives one of light reflected by the reflecting surface and passing forward through the left side of the shutter, and light reflected by the reflecting surface and passing forward through the right side of the shutter. A vertical line that is above a horizontal line that is orthogonal to the optical axis and that is irradiated to the right of the vertical line that is orthogonal to the optical axis, and that the other is above the horizontal line that is orthogonal to the optical axis and that is orthogonal to the optical axis The vehicle headlamp according to claim 1, wherein the vehicle headlight is irradiated to the left.   The vehicular headlamp according to claim 1 or 2, wherein the optical axis passes through a center of the upper edge of the shutter in the left-right direction. The bulb is an H4 bulb having a glass tube in which the light emission source is enclosed, and a hood that is enclosed in the glass tube and is provided so as to surround the lower side of the light emission source,
The vehicular headlamp according to any one of claims 1 to 3, wherein the bulb is arranged so that the hood is symmetrical with respect to the optical axis in a front view.

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