Lamp unit of vehicle headlamp

Abstract

An upper portion region and a lower portion region at a front side surface of a projector lens are constituted as up and down direction diverging portions provided with a plurality of lens elements extended substantially in a horizontal direction by a vertical sectional shape formed in a recessed and projected shape relative to a reference face of the front side surface. After diverging light emitted from the upper portion region and the lower portion region to a front side in an up and down direction, a diverging degree thereof is made to be able to be controlled accurately to thereby pertinently shade off the cutoff line. A spectroscopic color appearing at an upper vicinity of the cutoff line owing to a spectroscopic light phenomenon brought about when light reflected from a reflector transmits through the projector lens is made to be inconspicuous.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view showing a lamp unit of a vehicle headlamp according to an embodiment of the invention.

FIG. 2 is a sectional view taken along a line II-II of FIG. 1.

FIG. 3 is a detailed view of III portion of FIG. 2.

FIG. 4 is a detailed view of IV portion of FIG. 3.

FIG. 5 is a front view showing a single piece of a projector lens of the lamp unit.

FIG. 6 is a diagram perspectively showing a light distribution pattern formed on an imaginary vertical screen arranged at a position 25 m frontward from the lamp unit by light irradiated from the lamp unit to a front side.

FIG. 7 is a diagram enlarging to show a region at a vicinity of an elbow point of the light distribution pattern.

Claims

1. A lamp unit of a vehicle headlamp comprising: a projector lens arranged on an optical axis extended in a front and rear direction of a vehicle;a light source arranged on a rear side of a rear side focal point of the projector lens;a reflector that reflects light from the light source in a front direction to be proximate to the optical axis; anda shade that shields a portion of light reflected from the reflector,wherein at least a portion of a surface of the projector lens is constituted as an up and down direction diverging portion including a plurality of lens elements extended substantially in a horizontal direction by a vertical sectional shape formed in a recessed and projected shape relative to a reference face of the surface.

2. The lamp unit according to claim 1, wherein an upper end edge of the shade passes the rear side focal point of the projector lens, and the lamp unit forms a light distribution pattern having a cutoff line as an inverted projected image of the upper end edge of the shade.

3. The lamp unit according to claim 1, wherein the vertical sectional shape of the respective lens elements have waveform shapes.

4. The lamp unit according to claim 1, wherein the respective lens elements are formed to extend along intersected lines of the surface of the projector lens and planes including horizontal lines orthogonal to the optical axis at a vicinity of the rear side focal point of the projector lens.

5. The lamp unit according to claim 1, wherein the more remote is the position of the lens element from the optical axis in the up and down direction, to the larger value the angle of diverging light in the up and down direction by each of the lens elements is set.

6. The lamp unit according to claim 1, wherein the up and down direction diverging portions are formed at an upper portion region and a lower portion region remote from the optical axis in the up and down direction at the surface of the projector lens.

7. The lamp unit according to claim 6, wherein a plurality of the lens elements are formed discretely at predetermined intervals therebetween in the up and down direction at least piece by piece at respective regions of a center region disposed between the upper portion region and the lower portion region contiguous to respectives of the upper portion region and the lower portion region.

8. The lamp unit according to claim 1, wherein a cutoff line of a light distribution pattern is formed by an upper end edge of the shade, a plurality of dim light portions are formed on an upper vicinity of the cutoff line, and each of the dim light portions is extended in a strip-like shape substantially by constant width along the cutoff line, andthe dim light portions are formed to become gradually dark as the positions of the dim light portions are remote from the cutoff line.