The present invention relates to the rear lamps or light units of a vehicle and more specifi cally to a rear light unit of a vehicle and a method for controlling the lighting of said light unit.

The lighting of a light unit or lamp of a vehicle, in particular a rear lamp, traditionally takes place by switching a special selector on board the vehicle from a first light off posi tion to a second light on position, typically corresponding to the lighting of the driving lights or dipped beam headlamps of the vehicle, or by starting the (engine of the) vehicle if the selector is preset in the light on position.

The lighting is normally perceived by a subject outside the vehicle due to the constant lighting that the lamp takes on and the rapid increase in the brightness of the light source (or light sources) of the lamp is almost imperceptible when switching from the off to the on condition.

LED light sources are increasingly widespread in vehicles for the construction of front light units, or headlights (or headlamps), and rear light units, or lamps, which not only of fer greater efficiency in terms of life span and consumption of electric power, control of the directionality of the beam and homogeneity of lighting, but also lend themselves to a free spatial configuration, without constraints related to the size of the light source and the related power supply connections, as it would be in the case of bulb lamps. The use of LED light sources in automotive headlights and lamps takes place through the arrangement of linear arrays or two-dimensional arrays of LEDs within a diffuser body, the LEDs them selves emitting light at different wavelengths, therefore of different colors, for the different intended uses in the automotive sector according to the road traffic rules. Furthermore, it is known that LED array light sources can be controlled with varying intensities and the indi vidual elements can be activated at variable times so as to obtain dynamic chromatic ef fects, for example in the direction indicators so as to generate an incremental lighting ef fect in the turning direction or as moving from the direction of travel. The object of the present invention is to provide an efficient rear light unit for a vehicle, as well as to visually signal an ongoing starting condition of a vehicle through the vehicle lamps. Another object is to provide the vehicle with an innovative dynamic aesthetic ef fect.

According to the present invention, these objects are achieved by a rear light unit of a ve hicle having the features referred to in claim 1.

A further subject of the invention is a method for controlling the lighting of a vehicle lamp as claimed.

Particular embodiments are the subject of the dependent claims, whose content is to be un derstood as an integral part of the present description.

In summary, the present invention is based on the principle of implementing a vehicle lighting system, specifically a rear light unit, by means of a plurality of arrays of LED light sources, and of controlling the relative switching on and off of said arrays in a determined period of time, following a vehicle start command, in such a way as to represent a dynamic lighting effect, in particular a lighting effect similar to that which is generated in an aero nautical or aerospace jet engine. The lighting effect is such that first an array of inner cir cular light sources, preferably of orange or yellow light, lights up in a flashing mode, then an array of outer circular light sources, whose emitting surface is greater than the emitting surface of the array of inner light sources, preferably of red light, with initially increasing, then decreasing light intensity.

Further features and advantages of the invention will appear more clearly from the following detailed description of an embodiment thereof, given by way of non-limiting example with reference to the accompanying drawing, in which:

figure 1 shows a rear light unit of a vehicle in one embodiment of the invention;

figure 2 shows a block diagram of a system for controlling the lighting of the light unit of figure 1 ; and

figure 3 shows a flowchart of a method for controlling the lighting of the light unit of figure 1.

Figure 1 shows a rear light unit or lamp of a vehicle according to a currently preferred embod iment of the invention, in particular a right rear light unit, indicated as a whole with F.

The light unit F is housed in a body or shaped casing C which defines two seats side by side, of a generally circular shape, within which there are different light sources which create - in each seat - an overall lighting arrangement of the light unit.

The overall lighting arrangement of the light unit comprises an array of first light sources LI, arranged angularly offset along an inner circumferential region, and an array of second light sources L2 arranged, also angularly offset, concentrically to the first light sources LI along an outer circumferential region, and partially entering the array of first light sources LI accord ing to radial directions inserted between two successive light sources LI. A third, preferably single, light source L3 is arranged axially to the array of the first light sources LI and to the array of the second light sources L2.

Each light source LI, L2 and L3 is made by means of one or more light-emitting diodes, or LEDs, with which a light diffuser body acting as a light guide is associated to convey and dif fuse the light generated by the source, for example arranged at its bottom.

The first light sources LI have a diffuser body in the shape of a prismatic pinnacle, and pref erably include one or more light-emitting diodes (LED) for the diffusion of orange or yellow light adapted to realize a direction indicator.

The second light sources L2 have a blade-shaped diffuser body along whose median axis, from the face facing the interior of the arrangement, a septum L2’ emerges orthogonally which radially penetrates the circumferential region where the first light sources LI are ar ranged, substantially radially distributing itself concentrically to the third light source L3. They preferably include one or more light- emitting diodes (LEDs) for the diffusion of red light of variable intensity adapted to realize a tail and/or stop light. The third light source L3 has a gem-shaped diffuser body arranged at the top of a supporting cusp and preferably includes one or more light-emitting diodes (LEDs) for the diffusion of white light adapted to realize a reverse light.

Figure 2 shows a block diagram of a system for controlling the lighting of the light unit F.

A remote control unit or ignition key 10 owned by a vehicle driver is adapted to be operative ly connected in communication, for example in wireless communication, with a module 12 for receiving vehicle start signals, arranged on board the vehicle, for example integrated or coupled to a programmable control unit 14 of the vehicle. The module 12 for receiving vehi cle start signals is designed to receive a vehicle start signal emitted by the remote control unit or ignition key and consequently inform the control unit 14 that a vehicle start is in progress. The control unit 14 is coupled to a power amplifier module 16 to which it selectively supplies, according to a predetermined and programmable timing, lighting signals of the lighting ar rangement of the light unit. This occurs, for example, as a consequence of receiving a signal indicative of a vehicle start. The power amplifier module 16 is coupled to a plurality of PWM control modules 18, each associated with a respective lamp element 20, in this case a light unit F or a lighting arrangement thereof. The PWM control modules 18 are adapted to control an electrical signal to supply the light sources forming part of the corresponding lighting ar rangement, the timing of which is preset by the control unit 14, the intensity of the light emis sion being controlled by the unit 14 by adjusting the duty cycle of the electrical supply signal by means of the control modules 18.

Figure 3 shows a flow diagram of a method for controlling the lighting of the light unit F.

The start of the process can be triggered by a vehicle start signal, as described in the present embodiment, or by another process trigger signal, for example generated by the voluntary ac tuation of a control device by the driver or by a vehicle maneuver, for example an acceleration maneuver.

When the process starts, in step 100 the array of the first light sources FI is switched on. The lighting on of the sources FI is controlled in a flashing mode, for example with a peri- od of permanence in the on and off condition equal to 0.1 seconds, for a predefined total flashing time or for a predefined total number of flashes. In an exemplary embodiment, at least all the light sources LI of a lighting arrangement and preferably all the light sources LI of a light unit are controlled in synchronous flashing mode. Alternatively, it is possible to turn on the sources LI in succession over time, according to their spatial arrangement or according to another programmed lighting model.

At step 200, the array of the second light sources L2 switches on at a first level of mini mum predetermined light intensity.

Then in step 300, the array of first light sources LI switches off, i.e. their flashing stops, and subsequently, in step 400, the light intensity of the second light sources L2 is in creased, according to a predetermined increase curve, for example a linear increment curve. Upon reaching a predetermined maximum intensity threshold, or after a predeter mined time, the light intensity of the second light sources L2 is decreased at step 500 ac cording to a predetermined decrease curve, for example a linear decrease curve.

Subsequently, at step 600 a cycle condition is evaluated as a function of a predetermined number of iterations of the control process described above. Steps 100-500 are iterated for a predetermined number of times, after which the process ends, switching to a state in which the light unit remains on, for example in a lighting condition of tail lights, or in a state in which the light unit remains off, waiting for a lighting command by means of the activation of an on board selector of the lighting system.

Advantageously, with the succession of lighting commands of the arrays of sources LI and L2, and by virtue of their mutual spatial arrangement, as well as by effect of the different light emission color, it is possible to produce a dynamic light effect of the rear light units of a vehi cle depending on a vehicle start command, and this dynamic light effect is similar to the light effect that is generated in an aeronautical or aerospace jet engine.

Of course, the principle of the invention being understood, the manufacturing details and the embodiments may widely vary compared to what described and illustrated by way of a non-limiting example only, without departing from the scope of the invention as defined in the appended claims.