JP2012199156A - Vehicular headlight - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular headlight capable of shading off a boundary of bright and dark sides by a simple structure.SOLUTION: The vehicular headlight 1 includes a bulb 11 having an optical axis O which nearly horizontally extends forward, a concave reflecting surface 12 opened forward, and a projection lens 13 arranged in front of the reflecting surface 12 on the optical axis O. The reflecting surface 12 is arranged so as to reflect forward light from the bulb 11 while a first focal position F1 is located in the vicinity of the bulb 11 and a second focal position F2 is located on the optical axis O. The projection lens 13 is arranged so as to locate a focal position on a rear side in a light irradiation direction in the vicinity of the second focal position while a front optical surface is formed in a convex shape and a rear optical surface in the light irradiation direction is formed in a flat shape, and a plurality of pillar-shaped curved sections extended in a lateral direction and lined up in the vertical direction are arranged in projected or recessed states in a designated range of the center in the vertical direction among rear optical surfaces in the light irradiation direction.

Description

  The present invention relates to a vehicle headlamp.

Conventionally, vehicle headlamps such as automobile headlights have a structure as shown in FIG.
Specifically, in the vehicle headlamp 100 shown in this figure, the light emitting point of the light source 102 is arranged at the first focal point 101A of the reflecting mirror 101 formed as a spheroid having the major axis X as the rotation axis. A light-shading member (shade) 103 for light distribution formation is provided at or near the second focal point 101B of the reflecting mirror 101. Further, a projection lens (convex lens) 104 is provided in front of the reflecting mirror 101 in the irradiation direction of the long axis X so as to focus the light shielding member 103.

  In such a vehicle headlamp, as shown in FIGS. 4A and 5, the image of the light source 102 arranged at the first focal point 101A is formed at the second focal point 101B and then the projection lens 104. Will be projected forward. However, the light reflected by the lower half of the reflecting mirror 101, that is, the light that is projected forward and upward by the projection lens 104 is shielded by the light shielding member 103 and does not reach the projection lens 104. Thereby, upward light is not included in the irradiation light of the vehicle headlamp 100, and a passing light distribution shape D100 as shown in FIG. 4B is obtained.

JP 2008-135247 A

  However, in such a light distribution shape D100, a clear cut-off is formed at the upper edge of the light distribution, and the boundary between the bright part and the dark part is too clear, so no light is irradiated above the cut-off. There is a problem. Therefore, as shown in FIG. 4 (c), in a situation where there are few street lamps, the darkness outside the irradiation range by the headlamps seems to be further increased, and the road surface condition becomes difficult to grasp. (Refer to the shaded area in the figure), risk avoidance behavior may be delayed or cause fatigue during driving. As a technique for solving such a problem, although a technique for blurring the light / dark boundary in a standard conforming range by applying a texture to the convex surface of the projection lens 104 has been proposed, numerical management of the degree of blurring is required. Difficult and impractical.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicular headlamp that can blur a light / dark boundary with a simple configuration.

In order to solve the above problems, the invention according to claim 1 is directed to a vehicle headlamp.
A light source having an optical axis extending substantially horizontally toward the front in the light irradiation direction;
A concave elliptical reflective surface that opens forward in the light irradiation direction;
A projection lens disposed on the optical axis in front of the elliptical reflecting surface and in the light irradiation direction;
The elliptical reflecting surface is
The first focal position is located near the light source and the second focal position is located on the optical axis so as to reflect light from the light source forward in the light irradiation direction. ,
The projection lens is
The optical surface in the front of the light irradiation direction is convex, the optical surface in the rear of the light irradiation direction is formed flat,
It is arranged so that the focal position on the rear side in the light irradiation direction is located near the second focal position,
Among the optical surfaces behind the light irradiation direction, in a predetermined region at the center in the vertical direction,
A plurality of columnar curved portions extending in the horizontal direction and arranged in the vertical direction are concavely or convexly provided.

The invention according to claim 2 is the vehicle headlamp according to claim 1,
The predetermined area is:
Of the optical surfaces behind the light irradiation direction in the projection lens, the optical surfaces are regions having the same width in the vertical direction from the horizontal plane including the optical axis.

The invention according to claim 3 is the vehicle headlamp according to claim 1 or 2,
The predetermined area is:
The width in the vertical direction is 4 mm or less.

Invention of Claim 4 is the vehicle headlamp as described in any one of Claims 1-3,
The curved portion is cylindrical.

Invention of Claim 5 is the vehicle headlamp as described in any one of Claims 1-4,
The plurality of curved portions adjacent in the vertical direction are:
It is characterized by having different shapes.

  According to the first aspect of the present invention, the projection lens has a convex optical surface in the front of the light irradiation direction and a flat optical surface in the rear of the light irradiation direction. Since a plurality of columnar curved portions extending in the horizontal direction and arranged in the vertical direction are recessed or protruded in a predetermined region in the central portion of the optical system, the light emitted from the light source and rearward in the light irradiation direction Of the light incident on the surface, the light incident on the central portion is refracted in the vertical direction by each curved portion. Therefore, even when a cut-off is formed by shielding a part of light by the light shielding member, the light / dark boundary can be blurred by a simple configuration of a curved portion.

  According to the invention described in claim 5, since the plurality of curved portions adjacent in the vertical direction have different shapes, the degree of freedom in designing the method of blurring the light / dark boundary compared to the case of the same shape. Can be increased.

It is sectional drawing which shows the vehicle headlamp to which this invention is applied. It is a figure which shows a projection lens. It is a figure which shows the light distribution shape by the vehicle headlamp to which this invention is applied. (A) is sectional drawing of the conventional vehicle headlamp, (b), (c) is a figure which shows the light distribution shape by the conventional vehicle headlamp. It is the figure which showed in detail the locus | trajectory of the light ray in the conventional vehicle headlamp.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples. In the following description, “up”, “down”, “front”, “rear”, “left”, and “right” are respectively “up” and “up” of a vehicle equipped with a vehicle headlamp. "Down", "Front", "Back", "Left", "Right". Accordingly, the left and right directions are determined by looking from the back to the front (from the viewpoint of the driver).

  FIG. 1 is a schematic view showing a configuration of a vehicle headlamp 1 according to the present invention. More specifically, an end surface of the vehicle headlamp 1 cut along a vertical plane including an optical axis O described later is shown. FIG.

  As shown in this figure, the vehicle headlamp 1 is configured as an automobile headlamp, and includes a bulb 11, a reflecting surface 12, a projection lens 13, and a light shielding member 14.

  The bulb 11 is a light source in the present invention, and has an optical axis O that extends substantially horizontally toward the front in the light irradiation direction (left side in the figure, hereinafter referred to as the front). The bulb 11 is fixed and held so that the light emitting portion 11a extends along the optical axis O. As such a bulb 11, a bulb generally used for an automobile headlamp or an auxiliary headlamp can be used, and more specifically, for example, an incandescent bulb, a halogen bulb, or an HID (High Intensity Discharge). Such as a discharge lamp can be used.

  The reflecting surface 12 is a concave elliptical reflecting surface that opens forward so as to reflect light from the bulb 11 forward, and its first focal position F1 (rear focal position) is the bulb 11. And the second focal position F2 (front focal position) is located on the optical axis O. The reflecting surface 12 is formed so as to give a light distribution pattern for passing beams almost entirely. Here, the elliptical reflecting surface includes not only a rotating ellipsoid and an elliptic cylinder but also a free-form surface based on an ellipsoid. As such a reflective surface 12, a conventionally well-known thing can be used.

  The projection lens 13 is a lens that collects light traveling forward from the bulb 11 or the reflecting surface 12 and irradiates the light forward. The focal position of the projection lens 13 on the bulb 11 side (rear side) is the reflecting surface 12. Is disposed in front of the reflecting surface 12 on the optical axis O so as to be located near the second focal position F2.

  As shown in FIG. 2A, the projection lens 13 has an optical surface 13A on the front side and an optical surface 13B on the rear side (the bulb 11 side).

  Of these, the optical surface 13A is formed in a convex shape. As the shape of the optical surface 13A, an arbitrary convex shape such as an aspherical surface can be used.

On the other hand, the optical surface 13B is formed flat and has a rough surface region 130 at the center in the vertical direction.
Here, the rough surface region 130 in the present embodiment is a belt-like region having the same width in the vertical direction from the horizontal plane including the optical axis O in the optical surface 13B, and preferably the vertical width is 4 mm or less. It has become. In addition, the rough surface region 130 extends from the center of the optical surface 13B by the same length in the left-right direction. In the present embodiment, from the center of the optical surface 13B to both ends of the optical surface 13B in the left-right direction. It extends over. However, the position of the rough surface region 130, the vertical width, and the horizontal length are not limited to these.

As shown in FIGS. 2B and 2C, which are vertical sectional views of the projection lens 13, a plurality of curved portions 131 are formed in the rough surface region 130.
The bending portion 131 is recessed or protruded in a columnar shape extending in the left-right direction, and is arranged side by side in the up-down direction. Here, in the present embodiment, the curved portions 131 adjacent in the vertical direction have the same shape.

  The arc portion on the surface of the curved portion 131 may be a semicircle or an arc smaller than the semicircle. When the surface of the curved portion 131 is an arc smaller than a semicircle, for example, the width of the curved portion 131 in the vertical direction is set to about 0 to 1 mm, and the width (height, depth) of the curved portion 131 in the front-rear direction. Can be set to about 0 to 0.1 mm. However, the vertical width and height (or depth) of the curved portion 131 are not limited to these. The shape of the curved portion 131 is not limited to a cylindrical shape, and may be a prismatic shape such as a triangular prism shape or a quadrangular prism shape.

  The curved portion 131 described above is preferably formed when the projection lens 13 is molded, but may be formed by other methods. When polishing the optical surface 13B after molding, it is preferable that the curved portion 131 is recessed. Further, when polishing is performed in a concavo-convex shape, the polishing becomes rough without being easily applied, so that a moderate embossing effect can be obtained and effective in blurring the light / dark boundary.

  The light shielding member 14 is made of a light shielding material, and is arranged to hang from the vicinity of the second focal position F2 of the reflecting surface 12, that is, from the vicinity of the focal position of the projection lens 13 on the light source side. The light shielding member 14 forms a cut-off line in the light distribution pattern for the low beam by projecting the upper edge forward by the projection lens 13. As such a light shielding member 14, a conventionally known member can be used.

<Action and effect>
Then, the effect of the vehicle headlamp 1 is demonstrated.
First, light emitted from the bulb 11 travels forward toward the vicinity of the second focal position F2 by being reflected directly or by the reflecting surface 12, and is incident on the optical surface 13B of the projection lens 13.

At this time, a part of the incident light on the optical surface 13B is shielded by the light shielding member 14, thereby forming a cut-off line.
Further, the light incident on the rough surface region 130 of the optical surface 13B is refracted in the vertical direction by the respective curved portions 131.

  And the light which permeate | transmitted the inside of the projection lens 13 and was condensed by the optical surface 13A is irradiated ahead as a passing beam.

  Here, the trajectory of the light beam irradiated in the vehicle headlamp 1 in this embodiment is as shown in FIG. 1, and the trajectory of the light beam irradiated in the conventional vehicle headlamp is as shown in FIG. . Further, the shape of the passing beam irradiated in the vehicle headlamp 1 in the present embodiment is as shown in FIG. 3, and the locus of the light beam irradiated in the conventional vehicle headlamp is as shown in FIG. It becomes street. As can be seen from these drawings, in the vehicle headlamp 1 according to the present embodiment, compared with the conventional vehicle headlamp, the irradiation light is dispersed in the vertical direction and the light / dark boundary is blurred.

  As described above, according to the vehicular headlamp 1, the rear optical surface 13B of the projection lens 13 is formed flat, and the rough surface region 130 at the center in the vertical direction extends in the lateral direction. In addition, since the plurality of columnar curved portions 131 arranged in the vertical direction are recessed or protruded, the light that is emitted from the bulb 11 and incident on the optical surface 13B is incident on the rough surface region 130. The curved portions 131 are refracted in the vertical direction. Therefore, even when the cutoff is formed by shielding a part of the light by the light shielding member 14, the light emitted to the vicinity of the cutoff is diffused by the simple configuration of the curved portion 131, and the light / dark boundary is defined. Can be blurred.

  It should be noted that the present invention should not be construed as being limited to the above-described embodiment, and of course can be modified or improved as appropriate.

  For example, in the above embodiment, the curved portions 131 adjacent in the vertical direction have been described as having the same shape, but may have different shapes. Specifically, for example, the concave curved portion 131 and the convex curved portion 131 may be adjacent to each other in the vertical direction, and when the cylindrical curved portion 131 is adjacent to the vertical direction, these curved portions may be curved. The curvatures of the portions 131 may be different from each other. In these cases, it is possible to increase the degree of design freedom regarding how to blur the light / dark boundary as compared to the case where the plurality of curved portions 131 adjacent in the vertical direction have the same shape.

DESCRIPTION OF SYMBOLS 1 Vehicle headlamp 11 Valve | bulb 12 Reflecting surface 13 Projection lens 13A Optical surface 13B ahead of light irradiation direction Optical surface 130 behind light irradiation direction Rough surface area 131 Bending part F1 First focal position F2 Second focal position

Claims (5)

A light source having an optical axis extending substantially horizontally toward the front in the light irradiation direction;
A concave elliptical reflective surface that opens forward in the light irradiation direction;
A projection lens disposed on the optical axis in front of the elliptical reflecting surface and in the light irradiation direction;
The elliptical reflecting surface is
The first focal position is located near the light source and the second focal position is located on the optical axis so as to reflect light from the light source forward in the light irradiation direction. ,
The projection lens is
The optical surface in the front of the light irradiation direction is convex, the optical surface in the rear of the light irradiation direction is formed flat,
It is arranged so that the focal position on the rear side in the light irradiation direction is located near the second focal position,
Among the optical surfaces behind the light irradiation direction, in a predetermined region at the center in the vertical direction,
A vehicular headlamp characterized in that a plurality of columnar curved portions extending in a horizontal direction and arranged in a vertical direction are recessed or protruded. The vehicle headlamp according to claim 1,
The predetermined area is:
The vehicular headlamp characterized by being an area having the same width in the vertical direction from the horizontal plane including the optical axis, among the optical surfaces behind the light irradiation direction in the projection lens. The vehicle headlamp according to claim 1 or 2,
The predetermined area is:
A vehicle headlamp characterized by having a vertical width of 4 mm or less. In the vehicle headlamp according to any one of claims 1 to 3,
The vehicular headlamp characterized in that the curved portion is cylindrical. In the vehicle headlamp according to any one of claims 1 to 4,
The plurality of curved portions adjacent in the vertical direction are:
A vehicle headlamp characterized by having different shapes.

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