The present invention relates to a method and to an arrange- ment for controlling the headlights of automotive vehicles, and then in particular car headlights.

The design of modern cars in which the front part of the car dips makes it difficult to fit extra lights effectively. Extra lights impair the appearance of the car, constitute a greater accident risk to unprotected road users and make the car more difficult to wash. Extra lights also impair the aerodynamics of the car and have a negative effect on engine cooling, since they are normally fitted in front of the engine radiator.

There is a significant need to improve full-beam lighting for certain categories of driver who drive in certain regions, and particularly with respect to certain markets, even though conventional headlights will satisfy many users.

It has become progressively more usual for car owners to replace standard bulbs in existing headlamps with bulbs of greater power, in order to obtain more powerful full beam lighting. However, bulbs of greater power damage the reflectors, by changing the reflectance of the reflectors as a result of higher temperature in the headlamp. The higher temperature can even deform the reflectors, resulting in a distorted light image.

Furthermore, a more powerful bulb has the drawback of necessitating the driver to dip the lights earlier when driving in the dark on a typically trafficated road with repeated encounters with oncoming traffic interspersed with a clear road ahead, so as not to dazzle the drivers of oncoming traffic, as opposed to the case when using a standard bulb. This means that the driver's eyes must

constantly become accustomed to strong light, i.e. when the lights are on full beam, and a much weaker dipped light, where dipped lighting is used over a longer distance to prevent dazzling of oncoming traffic. This drawback is the reason why drivers do not normally have extra lights, such as long-distance lighting, switched-on when driving along roads in which oncoming vehicles are frequently encountered, therewith requiring the lights to be dipped repeatedly.

This problem is solved in accordance with the present invention by providing weak headlights for certain situations while eliminating the aforesaid drawback and, at the same time, eliminating the need of extra lighting.

The present invention thus relates to a method of controlling the full-beam lighting of automotive vehicles, particularly for cars, wherein the headlights are provided with light sources of a dischargeable type, and is characterized in that the light source is chosen so that when supplied with its nominal or rated power, it will produce a luminous flux which greatly exceeds the normal luminous flux of full-beam lighting; and in that in order to obtain a luminous flux which is normal for full-beam lighting, the light source is supplied with lower power; and in that means are provided for selectively supplying the light source with said lower power or with its nominal power. r

The invention also relates to an arrangement of the kind having the main characteristic features set forth in Claim 5.

The invention will now be described in more detail with reference to an exemplifying embodiment thereof and with reference to the accompanying drawings, in which - Figure 1 illustrates schematically a headlamp and associated power means; and

Figure 2 illustrates a light switch.

Figure 1 illustrates an arrangement for controlling the full beam headlights of automotive vehicles, particularly cars, wherein headlights 1 are provided with light sources 2 of a dischargeable kind. The reference numeral 3 in Figure l identifies the headlight reflector. Such light sources are available commercially and marketed, among others, by PHILIPS under the trade name Micro Power-Light.

Such light sources 2 are powered by a power means 4 which applies an alternating voltage across the light source. The voltage applied is normally a square-wave voltage. Such power means are also known and available commercially.

When applied to a car or to some other automotive vehicle, the power means 4 is connected to the vehicle electrical system by cables 5, 6 which supply the power means with direct current voltage.

According to the invention, the light source 2 is designed to produce a luminous flux which greatly exceeds the normal luminous flux of full-beam lighting when supplied with its nominal power. According to the invention, the power means

4 is designed to supply the light source 2 with lower power when in a first position such as to emit from the headlight l a full beam having a luminous flux which is normal for a full beam. Also provided is a means 7 with which the power means 4 can be switched selectively .from said first position to a second position in which the power means will supply the light source 2 with its nominal power.

According to one preferred embodiment of the invention, this lower power is between 40% and 70% of the nominal or rated power, preferably about 50%.

A full beam will normally have a luminous flux of 1,500 lumens for instance. This means that a preferred embodiment of the light source will generate a luminous flux of 3,000

lumens at nominal power.

According to one preferred embodiment of the invention, there is used a discharge lamp of the aforesaid kind having a nominal power of 35 Watts. In the case of standard head¬ lights, this light source will produce a luminous flux of 3,000 lumens when supplied with its nominal power. When supplied with a power of 18 Watts, the light source will produce a luminous flux of 1,500 lumens.

Conventional full-beam headlights, i.e. a headlight which emits a full-beam lobe, will generate a normal luminous flux when the light source is supplied with a power of 18 Watts. This means that when the light source is supplied with a power of 35 Watts, the light emitted by the headlight will correspond to a normal full beam in combination with a conventional long-distance headlight, because of the higher luminous flux. Such long-distance headlights are normally fitted to the vehicle as extra lighting.

According to one preferred embodiment of the invention, the means 7 includes a driver-operated switch, by means of which the power means can be switched between two said positions.

The switch is connected by means of a cable 8 to an appropri¬ ate known control circuit which is conveniently integrated with the power means and which functions to control the power output of said power means by voltage-regulating the output voltage and/or output current of the power means.

When the driver alternates between full beam and dipped beam in a normal manner, the beam will be switched between dipped lighting with a predetermined luminous flux given by the light source for dipped lighting and a full beam with the lower power input when the switch is in its first position, i.e. a full beam with normal luminous flux. When the switch is in its second position, the vehicle lighting will be

switched between said dipped lighting and a full beam lighting having the higher power input, i.e. lighting which corresponds to full-beam lighting in combination with long¬ distance lighting. This embodiment can be applied irrespec- tive of whether the dipped-beam headlights and the full-beam headlights are mutually separate or integrated in one and the same headlamp unit.

The switch may be an integral part of the normal light switch in a car or some other automotive vehicle. Figure 2 illus¬ trates an example of one such light switch 9.

The reference numeral 10 identifies automatic activation of the vehicle lights when the vehicle is started, for instance activation of the vehicle side lights and dipped/full beam lighting. All lights are switched off in position 11. A position light or the like is ignited in position 12.

Normal dipped lighting and normal full-beam lighting are activated in position 13. This enables the power means to drive the light source 2 at the lower power input. The driver alternates between dipped beam and full beam with the standard full beam switch, normally a lever placed on the steering wheel.

Standard dipped lighting with the stronger full-beam lighting is activated in position 14. This enables the power means to drive the light source 2 at its nominal power input. The driver alternates between dipped lighting and full-beam lighting with the aid of the standard full-beam switch.

Thus, the present invention obviates the need to fit extra lighting to the vehicle while still obtaining, when desired, the quality of light that an extra light would provide.

This eliminates the problems mentioned in the introduction.

Although the invention has been described above with refer¬ ence to a number of exemplifying embodiments thereof, it will be understood that modifications can be made. For instance, it is conceivable to include more than two power positions. Furthermore, light sources with other nominal power inputs can be chosen. The operating means 7 can also be constructed as a separate operating means. Furthermore, the invention may be applied to only one of the vehicle headlights or to both headlights. It is also conceivable to utilize the invention in the aforedescribed manner but in conjunction with a full- beam headlight which is also constructed for dipped lighting.

The present invention is not therefore limited to the described and illustrated embodiments thereof, since varia- tions and modifications can be made within the scope of the following Claims.