Patent Description:
Dynamic Bending Lights are increasingly present in current automotive lighting devices, becoming an upgrade to standard headlights and designed to make driving at night easier and safer.

To implement such a lighting functionality, there have been many solutions intended to provide a light pattern in the direction of the movement of the vehicle when it is entering a curve.

Mechanic-based solutions turn the lighting source as the steering wheel does, by means of an angular movement converter which directly uses the turning of the steering wheel to induce a turning in the lighting source. The lights will turn in whatever direction the wheel does, and this range of motion allows the lights to illuminate the road even when taking sharp turns or turning quickly.

This solution has received a huge number of improvements, so that the turning of the light source is more effective and also takes into account different driving circumstances.

An alternative solution for this problem is sought.

They all disclose a low beam with dynamic bending light function realized by a matrix beam.

However, the piloting method proposed in the prior art still needs to be perfected.

The invention provides an alternative solution for providing a dynamic bending light by a method for controlling a light pattern according to claim <NUM> and an automotive lighting device according to claim <NUM>. Preferred embodiments of the invention are defined in dependent claims.

In a first inventive aspect, the invention provides a method for controlling a low-beam light pattern provided by an automotive lighting device, according to claim <NUM>.

This method provides a controlled light pattern which includes a Dynamic Bending Light functionality, provided by the same lighting device that provides, for example, the low beam functionality, without moving parts and also being able to adapt to other driving circumstances, such as the driving speed or the presence of cars in the opposite direction.

The shifting in the operation should be understood as displacing one or more columns to the right or to the left, depending on the movement of the steering system, the light pattern provided in the matrix: if the original pattern in one row is, e.g., <NUM>-<NUM>-<NUM>-<NUM>-<NUM>, where <NUM> is a light turned off and <NUM> is a light turned on, after a <NUM> column shift to the left, the resulting pattern would be <NUM>-<NUM>-<NUM>-<NUM>-<NUM>, and after a <NUM> column shift to the right, the resulting pattern would be <NUM>-<NUM>-<NUM>-<NUM>-<NUM>. The subsequent creation of a third portion should be understood as the activation of the light sources which are associated to the blank spaces created when shifting the first portion. In another example, if the original pattern is <NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>, and the second portion is defined as <NUM>-<NUM>-<NUM> and the first portion is defined as <NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>, and the turning of the vehicle involves shifting <NUM> columns to the right, the second portion would remain the same <NUM>-<NUM>-<NUM>, but the second portion would shift <NUM> columns to the right, creating <NUM> columns of blank space: <NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>. The creation of a third portion between the first portion and the second portion would "fill this blank space", so that the final light pattern, after joining the first portion, the second portion and the third portion would be <NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>-<NUM>. The first "<NUM>" would belong to the second portion, the next two "<NUM>"s would belong to the third portion and the remaining two "<NUM>"s would belong to the first portion, which has been shifted to the right.

In some particular embodiments of this method, the light pattern further comprises a fixed beam provided by a first group of solid-state light sources, and the matrix arrangement comprises a second group of solid-state light sources, wherein the sum of the fixed beam and the dynamic portion gives result in the light pattern.

The term "solid state" refers to light emitted by solid-state electroluminescence, which uses semiconductors to convert electricity into light. Compared to incandescent lighting, solid state lighting creates visible light with reduced heat generation and less energy dissipation. The typically small mass of a solid-state electronic lighting device provides for greater resistance to shock and vibration compared to brittle glass tubes/bulbs and long, thin filament wires. They also eliminate filament evaporation, potentially increasing the life span of the illumination device. Some examples of these types of lighting comprise semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes (PLED) as sources of illumination rather than electrical filaments, plasma or gas.

The combination of a fixed beam and a matrix beam arrangement is a very common solution for current headlamps. The matrix arrangement is in charge of providing some lighting functionalities and, with the method of the invention, this matrix beam is also configured to provide a Dynamic Bending Light functionality without adding any additional element.

As indicated in claim <NUM>, the cut-off is a diagonal line of the low beam pattern, and its shape is important in automotive regulations. The fact that this cut-off belongs to the first portion means that this cut-off is being shifted when the vehicle turns. This is advantageous since the shifted pattern must also comply with the regulations.

In some particular embodiments of this method, before the step of shifting the operation of the light sources, the angular displacement of the steering system is sensed and converted into a number of positions to shift, and then the step of shifting is carried out using this number of positions to shift.

The matrix of solid-state light sources may have many different angular resolutions. Depending on the number and arrangement of these light sources, resolution may vary from <NUM>° per light source up to <NUM>° per light source. Hence, the angular position of the steering wheel may be translated in a different number of columns of the light array, depending on the density of these light sources in the array arrangement.

In some particular embodiments, this method further comprises the step of internally checking the luminous intensity in one point of the light pattern.

Due to the changes which are caused in the total light pattern due to the shifting of a portion of it, it is sometimes necessary to check if some of the light points which are regulated by the official law still accomplishes its luminous intensity standards.

In a second inventive aspect, the invention provides an automotive lighting device projecting a low-beam pattern according to claim <NUM>.

This automotive lighting device is configured to provide a Dynamic Bending Light functionality without moving parts, and using elements which are already available, but with a new configuration.

In some particular embodiments, the matrix arrangement comprises at least <NUM> solid-state light sources.

This invention can be useful for many types of lighting matrix/array-based technology, from the simplest one, with only a few thousands light sources, to more advanced ones, with several hundred thousand light sources.

Elements of the example embodiments are consistently denoted by the same reference numerals throughout the drawings and detailed description where appropriate:.

Accordingly, while embodiment can be modified in various ways and take on various alternative forms, specific embodiments thereof are shown in the drawings and described in detail below as examples. There is no intent to limit to the particular forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included.

<FIG> shows a general perspective view of an automotive vehicle <NUM> comprising an automotive lighting device <NUM> according to the invention.

This automotive vehicle <NUM> comprises a steering system <NUM> and a lighting device <NUM>. The lighting device <NUM> comprises a plurality of groups of LEDs <NUM> and a control centre <NUM> which is configured to control the operation of these groups of LEDs.

The control centre <NUM> is configured to modify the configuration of the LEDs <NUM> when the steering wheel of the vehicle is activated.

<FIG> shows a closer view of a particular embodiment of a lighting device <NUM> according to the invention.

This lighting device <NUM> comprises a first group of LEDs <NUM> which are grouped in a first lighting module <NUM> and a second group of LEDs <NUM> which are arranged in a matrix configuration <NUM>.

This matrix configuration <NUM> is a high-resolution module, having a resolution greater than <NUM> pixels. However, no restriction is attached to the technology used for producing the projection modules.

A first example of this matrix configuration comprises a monolithic source. This monolithic source comprises a matrix of monolithic electroluminescent elements arranged in several columns by several rows. In a monolithic matrix, the electroluminescent elements can be grown from a common substrate and are electrically connected to be selectively activatable either individually or by a subset of electroluminescent elements. The substrate may be predominantly made of a semiconductor material. The substrate may comprise one or more other materials, for example non-semiconductors (metals and insulators). Thus, each electroluminescent element/group can form a light pixel and can therefore emit light when its/their material is supplied with electricity. The configuration of such a monolithic matrix allows the arrangement of selectively activatable pixels very close to each other, compared to conventional light-emitting diodes intended to be soldered to printed circuit boards. The monolithic matrix may comprise electroluminescent elements whose main dimension of height, measured perpendicularly to the common substrate, is substantially equal to one micrometre.

The monolithic matrix is coupled to the control centre so as to control the generation and/or the projection of a pixilated light beam by the matrix arrangement <NUM>. The control centre is thus able to individually control the light emission of each pixel of the matrix arrangement.

Alternatively to what has been presented above, the matrix arrangement <NUM> may comprise a main light source coupled to a matrix of mirrors. Thus, the pixelated light source is formed by the assembly of at least one main light source formed of at least one light emitting diode emitting light and an array of optoelectronic elements, for example a matrix of micro-mirrors, also known by the acronym DMD, for "Digital Micro-mirror Device", which directs the light rays from the main light source by reflection to a projection optical element. Where appropriate, an auxiliary optical element can collect the rays of at least one light source to focus and direct them to the surface of the micro-mirror array.

Each micro-mirror can pivot between two fixed positions, a first position in which the light rays are reflected towards the projection optical element, and a second position in which the light rays are reflected in a different direction from the projection optical element. The two fixed positions are oriented in the same manner for all the micro-mirrors and form, with respect to a reference plane supporting the matrix of micro-mirrors, a characteristic angle of the matrix of micro-mirrors defined in its specifications. Such an angle is generally less than <NUM>° and may be usually about <NUM>°. Thus, each micro-mirror reflecting a part of the light beams which are incident on the matrix of micro-mirrors forms an elementary emitter of the pixelated light source. The actuation and control of the change of position of the mirrors for selectively activating this elementary emitter to emit or not an elementary light beam is controlled by the control centre.

In different embodiments, the matrix arrangement may comprise a scanning laser system wherein a laser light source emits a laser beam towards a scanning element which is configured to explore the surface of a wavelength converter with the laser beam. An image of this surface is captured by the projection optical element.

The exploration of the scanning element may be performed at a speed sufficiently high so that the human eye does not perceive any displacement in the projected image.

The synchronized control of the ignition of the laser source and the scanning movement of the beam makes it possible to generate a matrix of elementary emitters that can be activated selectively at the surface of the wavelength converter element. The scanning means may be a mobile micro-mirror for scanning the surface of the wavelength converter element by reflection of the laser beam. The micro-mirrors mentioned as scanning means are for example MEMS type, for "Micro-Electro-Mechanical Systems". However, the invention is not limited to such a scanning means and can use other kinds of scanning means, such as a series of mirrors arranged on a rotating element, the rotation of the element causing a scanning of the transmission surface by the laser beam.

In another variant, the light source may be complex and include both at least one segment of light elements, such as light emitting diodes, and a surface portion of a monolithic light source.

<FIG> shows a light pattern <NUM> projected by this lighting device. The first light module projects a fixed beam <NUM> and the matrix arrangement, in this case, is configured to project the remainder <NUM> of a low beam pattern.

In this case, this remainder <NUM> comprises the cut-off of the light pattern. In other lighting applications not covered by the claimed invention, such as a high beam, there is no cut-off, and the matrix arrangement projects a different light scheme.

<FIG> shows a division in this remainder <NUM> of the low beam pattern, projected by the matrix arrangement.

This remainder <NUM> has been divided into a first portion <NUM> and a second portion <NUM>. The first portion <NUM> will be shifted with the turning of the steering system of the vehicle, while the second portion <NUM> will remain still.

<FIG> shows the shifting of the first portion <NUM> to the right. The first portion comprises the cut-off and is shifted to the right according to the movement of the steering system of the vehicle. A third portion <NUM> is created between the first portion and the second portion, to fill the gap between them. The structure of this third portion is a linear interpolation between the last column of the first portion and the last column of the second portion, which are the columns which surround the gap which is filled by the third portion.

<FIG> show a similar example, but to the left. In this case, the first portion is on the left, and the cut-off is shifted with the first portion, but the second portion corresponds to a different profile than the second portion in the case of a right turn. The third portion, in any case, is a linear interpolation between the first and the second portions.

<FIG> shows a detailed view of the operation of this matrix arrangement. In this figure, <NUM> columns and <NUM> rows of the matrix arrangement are seen. In each cell, one number from <NUM> to <NUM> represents the luminous intensity of the associated LED, in intervals of <NUM>%. Thus, a number "<NUM>" represents <NUM>% of luminous intensity, and a number <NUM> represents <NUM>% of luminous intensity.

When the steering system turns, for example, 1º to the right, a method according to the invention converts this angular displacement into a number of rows, according to the resolution of the matrix arrangement. For example, in cases where the resolution is <NUM>. 2º per LED column, an angular displacement of 1º would be converted into <NUM> LED columns.

After calculating the number of LED columns, the control centre divides the dynamic portion in a first portion and a second portion and shifts the operation of the light sources of the matrix arrangement which are associated to the first portion <NUM> columns to the right, resulting an operation as the one shown in <FIG>. In this <FIG>, a blank space is shown between the shifted first portion <NUM> and the second portion <NUM>, which remains still.

<FIG> shows the final pattern, with a third portion <NUM> between the first portion <NUM> and the second portion <NUM>. In this <FIG>, the operation of the LEDs of the same <NUM> columns have changed, thus providing a Dynamic Bending Light functionality 1º to the right side of the automotive vehicle. Since a matrix arrangement may include several hundred thousand of LEDs and the resolution is usually comprised between <NUM>. 01º per LED column and <NUM>. 5º per LED column, this shifting usually involves many columns of LEDs.

After this shifting has been carried out, it is usually recommended to check if the lighting points which are defined in official regulations are providing a suitable value of luminous intensity. For example, the luminous intensity in point <NUM> may be checked to verify it this accomplishes luminous standards.

Claim 1:
Method for controlling a light pattern (<NUM>) provided by an automotive lighting device (<NUM>) of an automotive vehicle (<NUM>), wherein the light pattern (<NUM>) is a low beam pattern and the light pattern (<NUM>) comprises a dynamic portion (<NUM>) and a fixed portion (<NUM>), wherein the dynamic portion (<NUM>) of the light pattern (<NUM>) is provided by a matrix arrangement (<NUM>) of light sources (<NUM>) arranged in several columns by several rows, the method comprising the steps of
- sensing a turn in a steering system (<NUM>) of the automotive vehicle (<NUM>);
- dividing the dynamic portion (<NUM>) in a first portion (<NUM>) and a second portion (<NUM>) in a way that the luminous intensity of each of the first portion and of the second portion is not null; wherein the first portion (<NUM>) presents a higher luminous intensity than that of the second portion (<NUM>) and wherein the first portion (<NUM>) comprises a cut-off with a diagonal line of the low beam pattern;
- shifting the operation of the light sources (<NUM>) associated to the first portion (<NUM>) in the same direction as the sensed turn in a way that the cut-off is shifted according to the movement of steering system of the vehicle while the second portion (<NUM>) remains still, thus creating a plurality of blank spaces between the shifted first portion and the second portion; and
- creating a third portion (<NUM>) between the shifted first portion (<NUM>) and the second portion (<NUM>) to fill in the blank spaces, wherein the luminous intensity of the third portion is a linear interpolation between the column of the shifted first portion which is closest to the third portion and the column of the second portion which is closest to the third portion.