GB2179132A

GB2179132A - Headlamp for dipped light or fog light, of vehicles

Info

Publication number: GB2179132A
Application number: GB08616978A
Authority: GB
Inventors: Gerhard Lindae; Peter Perthus
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1985-08-10
Filing date: 1986-07-11
Publication date: 1987-02-25
Also published as: GB8616978D0; DE3528820C2; DE3528820A1; GB2179132B

Abstract

The headlamp for dipped light or fog light has a reflector (10), a diaphragm (16) forming the light/dark limit of the light beam, and an imaging lens (17). An additional diaphragm (15) with an upper and a lower optically active edge (20, 21) is arranged in the region of the diaphragm (16) so that it can be shifted vertically in such a way that both or either of the edges (20, 21) cut off part of the light beam. As a result, the light distribution on the roadway is influenced in such a way that either the distant region of the opposite side of the roadway or the foreground of the roadway is not illuminated; consequently, on the one hand, dazzling of oncoming traffic and, on the other hand, the vision of the vehicle driver are improved. <IMAGE>

Description

SPECIFICATION Headlamp, especially a headlamp for dipped light or fog light, of vehicles State of the art The invention relates to a headlamp, especially a headlamp for dipped light or fog light, of motor vehicles, according to the pre-characterizing clause of Claim 1. DE 3,334,459 Al makes known a headlamp of this type, the light distribution of which is designed for normal weather conditions and an average vehicle driver. This light distribution is not ideal in extreme weather conditions and/or for individual requirements of the vehicle driver, that is to say it could be designed in a more beneficial way in line with the optical conditions.

Advantages of the invention The invention rectifies the inadequacy demonstrated in the foregoing state of the art by technically simple means and in a functionally reliable manner and ensures that the light distribution can be adapted as effectively as possible to different influencing factors, such as, for example, extreme weather conditions and/or the individual driving behaviour of the vehicle driver. The adaptation can be effected either automatically by means of influencing variables or as a result of manual actuation by the vehicle driver.

Advantageous developments of the invention are described in the sub-claims. Claim 2 shows a way of reliably avoicing dazzling the drivers of oncoming vehicles even under unfavourable traffic conditions, and of no longer necessarily impairing the driver's own vision, especially when snow is falling or the road surfaces are bright; with Claim 3, both are possible separately from one another. Claim 4 makes it possible to effect a better individual adaptation of the light distribution.

Drawing An exemplary embodiment of the invention is illustrated in the drawing and explained in detail in the description of the figures. In the drawing, given in a reduced representation, Fig. 1 shows a motor-vehicle headlamp for dipped light with the essential parts in a threedimensional representation, Fig. 2 shows a view of the diaphragm and the additional dia phragm in the direction of the arrow II in Fig.

1 from the light exit orifice of the reflector, Fig. 2a shows the light distribution on the roadway obtained by means of the headlamp with the diaphragm arrangement according to Fig. 2, Fig. 3 corresponds to Fig. 2, but with the additional diaphragm shifted vertically up wards according to the arrow 111, Fig. 3a shows the light distribution associated with Fig. 3, Fig. 4 corresponds to Fig. 2, but with the additional diaphragm shifted vertically downwards according to the arrow IV, and Fig. 4a shows the associated light distribution.

Description of the exemplary embodiment A motor-vehicle headlamp for dipped light has a reflector 10, the meridional sections of which are curves of higher order, with a light source 11 which is arranged in the region of the focal point and is located approximately on the optical axis 12 of the headlamp and which is a spiral-wound filament of a filament bulb. A flange 14 forms, with the reflector 10, the exit orifice 13 of the latter. The horizontal plane 9 is indicated in segment form.

The following are arranged essentially at right angles to the optical axis 12 in front of the reflector 10 in the direction of the reflected beams according to the arrow II: an additional diaphragm 15, in front of this a diaphragm 16 and in front of the latter a lens 17. The vertical meridional section of the reflector 10 is part of an ellipse, with its inner focal point in the region of the light source 11 and with its outer focal point in the region of the diaphragm 16; the horizontal meridional section of the reflector 10 is also part of an ellipse, with its inner focal point likewise in the region of the light source 11, but with its outer focal point in the region of the lens 17.

The additional diaphragm 15 can be shifted upwards or downwards in the vertical direction according to the double arrow 18 and has an aperture 19 with an upper optically active edge 20 and a lower optically active edge 21; the latter only extends on the right of the optical axis 12 (as seen in the direction of the arrow LI) and, like the upper edge 20, is aligned essentially horizontally. The vertical extent of the aperture 19 is greater on the left of the optical axis 12 than on the right.

The diaphragm 16 is horizontally convex in the direction of the arrow 11. An optically active edge 22 is stepped in the region of the optical axis 12 and has a raised branch 8; the edge 22 forms the light/dark limit of the dipped light beam shown in Fig. 2a. Headlamps of this type, the reflectors of which are not bodies of revolution, produce the predetermined light distribution on the roadway essentially by means of the reflector 10, but inverted laterally and vertically, so that, in particular, the lateral and vertical inversion and the spreading of the light beam are effected by the lens.

Fig. 2 illustrates the normal vertical position of the additional diaphragm 15, in which a light beam 23 (hatched area) limited in the following way is obtained: at the top by the edge 20 of the additional diaphragm 15, at the bottom by the edge 22 of the diaphragm 16 and on both sides by the exit orifice 13 of the relector 10.

The lens 17 projects the light beam 23 on the roadway in the form of the light distribution according to Fig. 2a. Of this roadway, the centre strip 24, the left and right edges 25, 26, the boundary 27 represented by the vehicle and the horizon line 28 are shown.

The light distribution is represented by several isolux lines 30 (only two of which are numbered), and the light centre position 29 on the driver's own half of the roadway is shown.

Fig. 3 illustrates the additional diaphragm 15 which is shifted vertically upwards by the amount corresponding to the arrow Ill in relation to Fig. 2; as a result, the edge 21 of the additional diaphragm 15 is located above the higher branch of the edge 22 of the diaphragm 16, so that a shaded portion 31 is obtained; consequently, according to Fig. 3a, the distant region 31' (hatched) is not illuminated, and therefore possible dazzling of the onComing traffic is reliably prevented.

In Fig. 4, the additional diaphragm 15 is shifted vertically downwards by the amount corresponding to the arrow IV in relation to Fig. 2, so that, because the edge 20 is lower, a portion 41 (cross-hatched) is shaded and the relatively low light beam 43 is obtained.

According to Fig. 4a, as a result of the portion 41 a region 41' of the foreground of the roadway is not illuminated, and consequently, when the roads are bright or when there is snow, there is a corresponding reduction in the roadway illumination which increases the range of vision by lessening the extent by which the eye must adapt.

The additional diaphragm 15 can be divided in two, especially in the horizontal mid-plane 9 according to Fig. 1, so that the two edges 20, 21 can be shifted vertically according to the double arrow 18 independently of one another. Moreover, the two edges 20, 21 can either slope or curve in relation to the horizontal mid-plane 9.

Claims

1. Headlamp, especially a headlamp for dipped light or fog light, of motor vehicles with a reflector, the meridional sections of which are curves of higher order, with a light source arranged in the region of the reflector focal point, with a diaphragm which is located in front of the reflector and the optically active edge of which forms the light/dark limit of the light beam, and with an imaging lens in front of the diaphragm, characterized in that arranged in the region of the diaphragm (16) is an additional diaphragm (15) which can be shifted transversely relative to the optical axis (12) of the headlamp.

2. Headlamp according to Claim 1, with a raised branch of the optically active edge of the diaphragm for the asymmetrical dipped light or fog light, characterized in that the additional diaphragm (15) has an upper optically active edge (20) and, in the region of the raised branch (8), a lower optically active edge (21), and in that the additional diaphragm (15) can be shifted in the vertical direction (18).

3. Headlamp according to Claim 2, characterized in that the additional diaphragm (15) is divided in two so that the two edges (20, 21) can be shifted vertically (18) independently of one another.

4. Headlamp according to Claim 2, characterized in that the two edges (20, 21) of the additional diaphragm (15) slope and/or curve in relation to the horizontal mid-plane (9).

5. Headlamp according to one of the preceding claims, characterized in that the additional diaphragm (15) is arranged between the diaphragm (16) and the reflector (10).

6. Headlamp according to one of Claims 1 to 4, characterized in that the additional diaphragm (15) is arranged between the diaphragm (16) and the lens (17).

7. A headlamp substantially as herein described with reference to the accompanying drawings.