| 摘要 |
The arrangement has lenses mounted parallel to coach work contour, but with required beam orientation. A guide comprises several progressively elongated glass layers, stacked under spring compression in a reference frame. A filament or arc light source in an elliptical reflector illuminates the guide's entry face (the coplanar ends of the stacked layers), normally. Light penetrating each layer, axially, is internally reflected at its terminating facet. Opt., a layer may terminate in a stepped facet. Reflected beams exit through the side faces. Each is collimated by a Fresnel lens and directed on the illuminated area as the component of a composite beam oriented generally parallel to the vehicle's longitudinal axis, to which the guide is mounted transversely. Where a cut-off beam is required one or more component beams is obstructed by a mask fixed between guide and lens, or on the latter's exit face. For coach work designs employing rounded front corners, the invention seeks to fit headlight units as compactly as possible into the curved boundary surfaces (16). The light guide (12) is mounted diagonally within the available space, its principal axis aligned with the optical axis of the light source reflector (10). Light enters the guide through the face, normal to the axis, comprising the coplanar ends of its component layers. Each layer emits a component beam, reflected by its terminating facet, through the forward side face of the guide. These beams, each collimated by eg. a Fresnel lens, combine in a composite beam illuminating the desired area. A symmetrical lens construction would require the lenses to be mounted, individually, transversely for correct beam orientation; instead, lenses are molded with faces profiled to maintain beam orientation despite an angled mounting. This permits mounting in a continuous sequential array along a path paralleling the coach work curvature. Opt., the guide also is curved, further reducing the space required.
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