GB2367122A

GB2367122A - Anti-Dazzle Headlamp for a Motor Vehicle

Info

Publication number: GB2367122A
Application number: GB0121702A
Authority: GB
Inventors: Peter Gruber; Michael Hamm
Original assignee: Automotive Lighting Reutlingen GmbH
Current assignee: Marelli Automotive Lighting Reutlingen Germany GmbH
Priority date: 2000-09-08
Filing date: 2001-09-07
Publication date: 2002-03-27
Anticipated expiration: 2021-09-07
Also published as: GB2367122B; DE10044391A1; DE10044391B4; GB0121702D0

Abstract

A headlamp for a traffic system of driving on the right or driving on the left emits a dipped light beam with an asymmetrical upper light-dark cutoff in such a way that the dipped light beam has a greater range at the traffic side of the vehicle than at the oncoming traffic side. A headlight levelling device (22) is provided, by means of which the luminous range of the dipped light beam emitted by the headlamp may be varied. Upon a change to the different traffic system from that for which the headlamp is designed, the luminous range of the dipped light beam emitted by the headlamp is reduced by means of the headlight levelling device (22) to such an extent that said beam causes no dazzling of the oncoming traffic. A switch is provided for the driver of vehicle specifically for this purpose.

Description

2367122 Headlamp for motor vehicles

Background art

10 The invention proceeds from a headlamp for motor vehicles according to the preamble of claim 1.

Such a headlamp is known from DE 199 05 173 Al. Said headlamp is designed for a traffic system of driving on the 15 right or driving on the left and emits a dipped light beam, which has an asymmetrical light-dark cutoff. Thus, the dipped light beam has a greater range at the traffic side of the vehicle, i.e. in the case of driving on the right the right side and in the case of driving on the left the 20 left side, than at the oncoming traffic side of the vehicle. The headlamp comprises a headlight levelling device, by means of which the luminous range of the light beam emitted by the headlamp may be adjusted. The headlight levelling device is provided in particular to 25 compensate a change of the inclination of the headlamp, which is firmly connected to the body of the motor vehicle so that its inclination alters with the inclination of the body. By means of the headlight levelling device the luminous range of the light beam emitted by the headlamp 30 may in particular be reduced so as to avoid dazzling the oncoming traffic when the motor vehicle is carrying a heavy load. When the motor vehicle equipped with the headlamp, is temporarily being driven in a different traffic system from that for which the headlamp is designed, this leads to dazzling of the oncoming traffic because the latter is then situated at the side where the dipped light beam has the greater range. In said case, to avoid dazzling the oncoming traffic, it is known to affix opaque stickers to 5 those parts of a covering pane of the headlamp, through which the portion of the dipped light beam with the greater range passes. In said case, however, it is difficult for the vehicle driver to locate the correct parts of the covering pane and affix the stickers correctly.

10 Alternatively, in the case of headlamps based on the.projection principle it is known to provide a movable screen which, upon a change of traffic system, is moved into a position, in which it screens off the part of the dipped light beam with the greater range. The outlay for 15 manufacture and assembly of the headlamp is however increased by said screen.

Advantages of the invention 20 In contrast, the headlamp according to the invention having the features according to claim 1 has the advantage that by utilizing the headlight levelling device, which is in any case provided, dazzling of the oncoming traffic upon a change of traffic system is easily avoided without any 25 additional outlay.

Advantageous refinements and developments of the headlamp according to the invention are indicated in the dependent claims.

Drawings Two embodiments of the invention are illustrated in the drawings and described in detail below. Figure 1 shows a longitudinal section through a headlamp according to a first embodiment with a headlight levelling device, Figure 2 a longitudinal section through a headlamp according to a second embodiment with a headlight levelling device and 5 Figure 3 a measuring screen disposed in front of the headlamp.

Description of the embodiments

10 A headlamp for motor vehicles, which is illustrated in Figures 1 and 2, is used at least to emit a dipped light beam. The headlamp is fastened in the usual manner to a part of the body of the motor vehicle. The headlamp is illustrated in Figure 1 according to a first embodiment and 15 in Figure 2 according to a second embodiment. First of all, the headlamp according to the first embodiment is described in detail below.

The headlamp according to Figure 1 is constructed on the 20 reflection principle and comprises a reflector 10, into which a light source 12 is fitted. The light source 12 may be an incandescent lamp or a gas discharge lamp. The reflector 10 is disposed in a mount 14 designed e. g. in the form of a housing. The housing 14 has a light outlet 25 opening, which is covered by a light-transmitting pane 16. The covering pane 16 may be of a substantially smooth construction so that light passes in a subst antially uninfluenced manner through it. Alternatively, the covering pane 16 may at least in regions comprise optical 30 profiles 17, by means of which light passing through is deflected and/or diffused. The dipped light beam emitted by the headlamp is required to have an upper light-dark cutoff and to produce a defined luminous intensity distribution. This may be achieved in that the shape of the reflector 10 is determined by means of numerical methods in such a way that the reflector reflects light emitted by the light source 12 in the form of the dipped light beam having the required light-dark cutoff, without 5 screens or optical profiles on the covering pane being required for said purpose. Alternatively, to produce the required light-dark cutoff it is possible to dispose in the beam path between the light source 12 and the reflector 10 one or more screens 18, which screen off some of the light 10 emitted by the light source 12. If the light beam reflected by the reflector 10 still does not produce the required luminous intensity distribution, the covering pane 16 may be provided with the optical profiles 17, by means of which the light beam reflected by the reflector 10 is 15 deflected and/or diffused in such a way that the dipped light beam emitted from the headlamp produces the required luminous intensity distribution.

Figure 3 shows a measuring screen 80, which is disposed at 20 a distance in front of the headlamp and is illuminated by the dipped light beam emitted by the headlamp. The measuring screen 80 represents the projection of a road, which lies in front of the headlamp and would be correspondingly illuminated. The measuring screen 80 has a 25 horizontal centre plane HH and a vertical centre plane VV, which intersect at a point HV. The dipped light beam emitted by the headlamp illuminates a region 82 on the measuring screen 80. The headlamp is designed for driving on the right so that its own traffic side is the right side 30 of the measuring screen 80 and the oncoming traffic side is the left side of the measuring screen 80. The region 82 is delimited in an upward direction by a light-dark cutoff, which at the oncoming traffic side comprises a horizontal portion 83, which extends slightly below the horizontal centre plane HH of the measuring screen 80. At the traffic side of the vehicle the light-dark cutoff comprises a portion 84, which ascends from the horizontal portion 83 towards the right and is adjoined by a horizontal portion 5 85. Alternatively, the light-dark cutoff at the traffic side of the vehicle may comprise only the ascending portion 84 or the portion 85 running horizontally but higher than the portion 83. The light-dark cutoff 83, 84, 85 of the region 82 and hence of the dipped light beam is therefore 10 asymmetrical and the dipped light beam has a greater range at the traffic side of the vehicle than at the oncoming traffic side. The luminous intensity distribution in the region 82 is illustrated by a plurality of lines 86 of equal luminous intensity.

The reflector 10 is supported in the housing 14 so as to be capable of swivelling about an at least approximately horizontally extending axis 20. The headlamp has a headlight levelling device 22 comprising an adjusting 20 element 24, which acts upon the reflector 10 and by means of which the reflector 10 may be swivelled about the axis 20. Upon swivelling of the reflector 10 about the axis 20, the luminous range of the dipped light beam emitted by the headlamp and hence the position of the light-dark cutoff 25 83, 84, 85 varies in vertical direction. When the reflector 10 is swivelled about the axis 20 in a downward direction, the luminous range is reduced and the light-dark cutoff 83, 84, 85 is in a lower position. The headlight levelling device 22 comprises a drive 26, which is 30 preferably an electric motor with a gear unit but may alternatively be a hydraulic or pneumatic actuator. By means of the drive 26 the adjusting element 24 is moved in the direction of the double arrow 28 according to Figure 1, with the result that the reflector 10 is swivelled about the axis 20.

For activation of the drive 26 a switching element 30 is 5 provided, which is disposed in the interior of the motor vehicle and is to be operated manually by the vehicle driver. By means of the switching element 30 the drive 26, in the form of an electric motor, of the headlight levelling device 22 is connected to a power source, wherein 10 the battery of the motor vehicle is preferably used as said power source. The switching element 30 has a plurality of defined positions 32, into which it may be brought by the vehicle driver, wherein each position of the switching element 30 corresponds to a swivel position of the 15 reflector 10 about the axis 20, into which position the reflector 10 is brought by the headlight levelling device 22. A change of the inclination of the body of the motor vehicle leads also to a change of the inclination of the headlamp fastened to said body and consequently to a change 20 of the luminous range of the dipped light beam emitted by the headlamp. A basic setting of the reflector 10 about the axis 20 is effected for a defined inclination of the body of the motor vehicle, when the latter is not laden. During said process, the reflector 10 is swivelled about 25 the axis 20 until the light-dark cutoff 83, 84, 85 in vertical direction adopts the correct position shown in Figure 3 and so the luminous.range of the dipped light beam is set correctly. When the inclination of the body and of the headlamp changes in such a way that the luminous range 30 of the dipped light beam increases and so the light-dark cutoff 83, 84, 85 is in too high a position, the reflector 10 may be swivelled downwards about the axis 20 by the headlight levelling device 22 in such a way that the lightdark cutoff 83, 84, 85 readopts the specified position and the luminous range of the dipped light beam is set correctly. In the case of the headlamp according to the first embodiment, therefore, manual headlight levelling control is provided, which the vehicle driver operates by 5 means of the switching element 30.

The motor vehicle, which is equipped with at least one previously described headlamp, may also he driven temporarily in a country having a different traffic system 10 from that for which the headlamp is designed. For example, a motor vehicle.with a headlamp designed for driving on the right may be driven in a country where one drives on the left, and vice versa. In said case, the traffic side of the vehicle and the oncoming traffic side are transposed 15 and the dipped light beam emitted by the headlamp has a greater range at the oncoming traffic side than at the traffic side of the vehicle. According to the invention it is provided that, in said case, by means of the headlight levelling device 22 the luminous range of the dipped light 20 beam emitted by the headlamp is reduced and so the lightdark cutoff 83, 84, 85 is shifted downwards to such an extent that at the oncoming traffic side no dazzling of the oncoming traffic occurs. In Figure 3 the position of the region 82a with the light-dark cutoff 83a, 84a, 85a, given 25 a reduction of the luminous range by means of the headlight levelling device, is illustrated by dashed lines. The lowering of the region 82a is effected e.g. to such a extent that the ascending portion 84a and the horizontal portion 85a of the light-dark cutoff no longer project 30 above the horizontal centre plane HH or are disposed below the latter.

It is preferably provided that the switching element 30 has a special switching position 32a, into which it may be brought when the motor vehicle is being driven in a country having the different traffic system. A suitable marking may be provided on the switching element 30 for the switching position 32a. Alternatively or additionally the 5 operating manual of the motor vehicle may contain an instruction for the vehicle driver that, when driving the motor vehicle in a country having the different traffic system, the switching element 30 is to be brought into the switching position 32a. Upon returning to the original 10 traffic system, the switching element 30 is to be reset in dependence upon the load of the motor vehicle.

Figure 2 shows the headlamp according to a second embodiment. Said headlamp is constructed on the projection 15 principle and comprises a reflector 40, into which a light source 42 in the form of an incandescent lamp or a gas discharge lamp is fitted. Light emitted by the light source 42 is reflected by the reflector 40 in the form of a convergent light beam. The reflector 40 may be of an 20 ellipsoidal or quasi-ellipsoidal shape. Disposed in light emitting direction 43 downstream of the reflector 40 is a screen 44, which extends substantially below the optical axis 41 of the reflector 40. The screen 44 has a top edge 45. Disposed in light emitting direction 43 downstream of 25 the screen 44 is a lens 46, through which light, which has been reflected by the reflector 40 and travelled past the top edge 45 of the screen 44, passes. The reflector 40 together with the light source 42, the screen 44 and the lens 46 forms a headlamp unit 48, which is disposed in a 30 mount 50 in the form of a housing. The position and shape of the light- dark cutoff 83, 84, 85 of the dipped light beam is determined by the top edge 45 of the screen 44. The housing SO has a light outlet opening, which is covered by a light-transmitting pane 52. The headlamp unit 48 is supported in the housing 50 so as to be capable of swivelling about an at least approximately horizontally extending axis 54. The headlamp has a headlight levelling device 56, which may be designed as in the first embodiment 5 and by means of which the headlamp unit 48 may be swivelled about the axis 54.

The headlight levelling device 56 comprises a drive 58 preferably in the form of an electric motor. The headlight 10 levelling device 56 is controlled by a control device 60.

Signals are supplied to the control device 60, which determines from said signals the inclination of the body of the motor vehicle and hence the inclination of the headlamp. The control device 60 moreover determines the 15 manner, in which the headlight levelling device 56 has to be activated in order, given the respective inclination of the body, to keep the luminous range of the dipped light beam emitted by the headlamp at least approximately constant, and the headlight levelling device 56 is 20 activated in said manner. Thus, in the case of the headlamp according to the second embodiment, automatic headlight levelling control is provided. A switching element 62 is moreover provided, which is disposed in the interior of the motor vehicle and is to be operated 25 manually by the vehicle driver and by means of which the headlight levelling device 56 may be activated. When the motor vehicle is being driven in a country having a different traffic system, the switching element 62 is used to swivel the headlamp unit 48 in a downward direction 30 about the axis 54 in such a way that the dipped light beam emitted by the headlamp does not cause any dazzling of oncoming traffic. Upon operation of the switching element 62 the headlight levelling device 56 is activated independently of the control device 60 and hence independently in such way that the headlamp unit 48 is swivelled downwards about the axis 54 and the region, which is illuminated by the dipped light beam emitted by the headlamp, adopts the position 82a shown in Figure 3 and the 5 light-dark cutoff of said region adopts the position 83a, 84a, 85a. Instead of the switching element 62, activation of the headlight levelling device 56 may be effected by means of an actuator of a CAN bus system. By means of the switching element 62 and/or the actuator it is possible to 10 act, instead of directly upon the headlight levelling device 56, upon the control device 60 such that the latter activates the headlight levelling device 56 in such a way that the headlamp unit 48 is lowered into the required position.

is It is preferably provided that, upon operation of the switching element 62, the headlight levelling device 56 is no longer activated by the control device 60 and the headlamp unit 48 remains in the lowered swivel position 20 about the axis 54 until the switching element 62 is returned to its original position by the vehicle driver. The switching element 62 may be provided with a symbol indicating its function or with an appropriate inscription. Alternatively or additionally the operating manual of the 25 motor vehicle may contain an instruction for the vehicle driver that, when driving the motor vehicle in a country having the different traffi,c system, the switching element 62 is to be operated accordingly and, upon returning to the original traffic system, is to be returned to its original 30 position.

The manual headlight levelling control by means of the switching element 30, described above for the first embodiment, may naturally be used also for a headlamp based on the projection principle and, in a corresponding manner, the automatic headlight levelling control by means of the control device 60, described for the second embodiment, may be used also for a headlamp based on the reflection 5 principle.

Claims

1. Headlamp for motor vehicles, which is designed for a 10 traffic system of driving on the right or driving on the left and emits a dipped light beam with an asymmetrical upper light-dark cutoff (83, 84, 85) in such a way that the dipped light beam has a greater range at the traffic side of the vehicle than at the oncoming traffic side, is wherein a headlight levelling device (22; 56) is provided, by means of which the luminous range of the dipped light beam emitted by the headlamp may be varied, characterized in that, upon a change to the different traffic system from that for which the headlamp is 20 designed, the luminous range of the dipped light beam emitted by the headlamp is reduced by means of the headlight levelling device (22; 56) in such a way that the range of said beam at the oncoming traffic side of the different traffic system is reduced to such an extent 25 that said beam causes no dazzling of the oncoming traffic.

2. Headlamp according to claim 1, characterized in that the headlight levelling device (22) is activated by means of 30 a switching element (30), which is to be operated by the vehicle driver.

3. Headlamp according to claim 2, characterized in that the switching element (30) has a defined switching position (32a), into which it is to be brought upon a change to the different traffic system.

4. Headlamp according to claim 1, characterized in that the 5 headlight levelling device (56) is activated by means of a control device (60) in such a way that independently of the inclination of the body of the motor vehicle the luminous range of the dipped light beam emitted by the headlamp is kept at least approximately constant, and 10 that a switching element (62) to be operated by the vehicle driver is provided, by means of which upon a change to the different traffic system the headlight levelling device (56) is at least indirectly activated.