EP4415482A1 - Lighting means with several leds as light sources for two light functions with an overlap of the area for their implementation and vehicle lamp equipped therewith - Google Patents

Abstract

A lighting device (01) with a plurality of LEDs (02) as light sources for two types of lighting functions with overlap of the lighting surfaces provided for their implementation in a common lighting surface (bi-function lighting surface) and a vehicle lamp equipped with such a lighting device are described. The lighting device (01) comprises at least one LED driver arrangement (03) with separate inputs (04) for control signals for requesting the two lighting functions and a plurality of switchable outputs (05) each representing preset constant current sources, to which the LEDs (02) or LED strands made up of a plurality of LEDs (02) arranged in series are connected, wherein at least the LEDs (21) of the common lighting surface are connected in parallel to a plurality of outputs (51, 52, 53).

Description

The invention relates to a lighting means according to the preamble of claim 1, and to a vehicle lamp equipped with such a lighting means according to the preamble of claim 14.

A vehicle lamp comprises, for example, a lamp interior essentially enclosed by a lamp housing with at least one light opening and a light disc closing it, and at least one lamp housed therein and comprising at least one light source for at least one lighting function of the vehicle lamp.

Examples of vehicle lights are repeater flashing lights arranged on the front of the vehicle, on the sides of the vehicle and/or on the side mirrors as well as on the rear of the vehicle, exit lights, for example for ambient lighting, side marker lights, brake lights, fog lights, reversing lights, as well as typically high-mounted third brake lights, so-called central, high-mounted braking lights, daytime running lights, headlights and fog lights also used as cornering or curve lights, as well as combinations thereof.

Such a combination is regularly implemented in the well-known rear lights, for example. These combine repeat indicators, side marker lights, brake lights, fog lights and reversing lights, to name just one of the many combinations implemented in rear lights. This list is not intended to be complete, nor does it mean that all of the lights mentioned must be combined in one rear light. For example, just two or three of the lights mentioned or other lights can be combined in a common lamp housing of a rear light.

Every vehicle light, in particular an automobile light, fulfils one or more tasks or functions depending on its design. A lighting function of the vehicle light is provided to fulfil each task or function. Lighting functions are, for example, a function for illuminating the roadway when designed as a headlight, or a signal function when designed as a signal light, such as a repeat flashing light function to indicate the direction of travel or a brake light function to indicate braking activity, or e.g. a side light function, such as a tail light function, to ensure that the vehicle is visible during the day and/or at night, such as when designed as a rear light or daytime running light.

Each lighting function must meet a light distribution requirement, for example one that is specified by law. The light distribution defines the minimum luminous fluxes that must be maintained, colloquially referred to as brightness, in the minimum solid angle ranges that must be maintained.

Different brightnesses or visibility ranges as well as different light colors are assigned to the individual lighting functions.

• eine mittels einer oder mehrerer Lichtquellen hinterleuchtete, transparente Flächenpartie beispielsweise einer Lichtscheibe oder - bei klarer Lichtscheibe - einer zwischen Lichtscheibe und Lichtquelle angeordneten Optikscheibe,
• eine mittels einer oder mehrerer Lichtquellen ausgeleuchtete Flächenpartie beispielsweise eines Reflektors,
• eine Ansichtsfläche einer oder mehrerer Lichtquellen, sowie
• Kombinationen hiervon.

When looking from outside the interior of the luminaire onto the light disc or through it, each lighting function is implemented by at least one luminous surface in such a way that each lighting function has one luminous surface available at least while it is being fulfilled. Examples of luminous surfaces are:

• a transparent surface area backlit by one or more light sources, for example a light disc or - in the case of a clear light disc - an optical disc arranged between the light disc and the light source,
• a surface area illuminated by one or more light sources, for example a reflector,
• a viewing surface of one or more light sources, as well as
• Combinations thereof.

Due to their high efficiency in converting electrical current into light visible to the human eye, semiconductor light sources such as inorganic light-emitting diodes or organic light-emitting diodes are increasingly being used as light sources for vehicle lights.

Inorganic light-emitting diodes consist of at least one light-emitting diode semiconductor chip, or LED chip for short, and at least one primary optics, which is molded on, for example, by injection molding and completely or partially envelops the at least one LED chip. Vehicle lights are also known in which pure LED chips are used without molded-on primary optics.

Known are inorganic light-emitting diodes for through-hole mounting (THT; Through Hole Technology), surface-mountable (SMD; Surface Mounted Device) LEDs and LEDs in which the LED chip is bonded directly to the lamp carrier using bare mounting technology (COB; Chip On Board).

For the sake of completeness, it should be mentioned that other contacting methods are also possible, such as the so-called flip-chip structure, in which the contact means of the LED chip are directly connected to a contacted substrate. In these cases, no bonding wire is used.

For the sake of simplicity, the following will no longer distinguish between inorganic light-emitting diodes and LED chips, and instead the term LED will be used to refer to both, unless explicitly stated otherwise. The outstanding properties of LEDs compared to other conventional light sources in lamps are a significantly longer service life and a significantly higher light output with the same power consumption. In other words, LEDs have a lower power consumption than other light sources for the same light intensity. This means that when one or more LEDs are used as the light source of a lamp, for example in a vehicle light, the load on a vehicle's on-board network intended for power supply can be reduced, thereby saving energy in the vehicle. Furthermore, LEDs have a much longer service life than other light sources that could be used in a vehicle light. The longer service life increases operational reliability and thus the quality of the vehicle light, among other things due to the lower failure rate.

In addition to their higher light output, another reason for the increased use of semiconductor light sources, such as LEDs (inorganic light-emitting diodes) and/or OLEDs (organic light-emitting diodes) in conjunction with the Fulfillment of lighting functions in vehicle lights essentially in their short, barely measurable activation time from the start of a current application to the emission of light. In contrast to an incandescent lamp, the light is emitted from the very first moment of current application with full luminous intensity proportional to the current strength. This results in an increased perceptual power of lighting functions implemented using semiconductor light sources, accompanied by an increase in the road safety of vehicles participating in road traffic that are equipped with vehicle lights with corresponding lamps.

To operate semiconductor light sources as light sources for a lamp of a vehicle light, one or more more or less complex electronic control circuits are required, which can be arranged, for example, on one or more lamp carriers of the lamp and housed in the interior of the lamp.

A simple example of an electronic control circuit relates to the equalization of different brightnesses of individual LEDs or of LED strings within a group of jointly operated LEDs arranged on one or more light source carriers. Such an electronic control circuit consists of at least one or more series resistors for adjusting the forward voltage of the LEDs to the vehicle electrical system. For example, it is known to sort the LEDs in so-called binning according to forward voltage and intensity. In order to compensate for differences between several LED strings, each of which consists of LEDs connected in series with the same forward voltage and intensity, and to obtain a homogeneous brightness distribution of the neighboring LED strings made up of LEDs with different forward voltage and intensity, at least each LED string is provided with a different series resistor.

Semiconductor light sources also require separate failure detection when used as a light source in vehicle lights. This is due to the low power consumption of LEDs and OLEDs in general. For example, a control unit installed in a vehicle is not able to detect a change in the power consumption from the vehicle electrical system that corresponds to the failure of one or more LEDs or OLEDs, since any resulting change in the vehicle electrical system voltage would be below the voltage that occurs during normal operation of a vehicle. An electronic circuit arrangement for failure detection, for example housed in the vehicle light, detects the failure of one or more semiconductor light sources in the vehicle light, e.g. by means of one or more comparators, and informs the control unit. Such an electronic circuit arrangement for failure detection can be implemented by an electronic control circuit, for example, mounted on the lamp carrier.

The use of semiconductor light sources instead of conventional light sources, especially in vehicle lights, also results in changes in the technical structure of the power supply.

In contrast to conventional light sources with an almost constant ohmic resistance, semiconductor light sources have a non-linear current/voltage characteristic. In order to be able to use their high efficiency and a consistently high light output, semiconductor light sources must be operated at a correct operating point. Otherwise, fluctuating brightness and poor efficiency would be the result. Due to series variations in the manufacture of semiconductor light sources, their operating point cannot be set precisely using a simple voltage source. This is only possible with a constant current source, also known in this context as an LED driver. This is a more or less complex electronic control circuit made up of one or more electronic components, for example on the lamp carrier of a semiconductor light source. An LED driver can either be constructed discretely with individual electronic components, or it can comprise an integrated electronic circuit component, such as a driver IC (IC; Integrated Circuit).

It is important to emphasize at this point that the term LED driver does not represent any restriction with regard to the semiconductor light sources that can be connected. In the following, the term LED is therefore used to represent any type of semiconductor light source, unless explicitly stated otherwise.

• LED-Vorwiderstand,
• lineare LED-Treiber, und
• getaktete LED-Treiber.

Well-known LED drivers are:

• LED series resistor,
• linear LED drivers, and
• clocked LED drivers.

The cheapest version is the LED series resistor. This consists of an ohmic resistor that is connected in series with the LED. It limits the current flow to a previously calculated value. This LED driver variant is of course extremely cost-effective, but has some disadvantages, such as the dissipation of the power loss proportional to the voltage drop across the ohmic resistor. This means that the advantages of the high efficiency of the LED are at least partially lost. On the other hand, the LED reacts directly to fluctuations in the supply voltage with brightness fluctuations, since there is no active control in this economy version.

A linear LED driver converts a higher input voltage to the set operating current of the LED. Due to the voltage difference between the input and output, the linear LED driver has a control range to adjust to fluctuating vehicle voltage. This means that there are no fluctuations in the brightness of the LED.

Linear LED drivers have the disadvantage that the voltage drop and operating current of the LED result in power loss. This is simply converted into heat and reduces the efficiency of the LED. The advantages include active control, simple circuit design and a low price.

A clocked LED driver works in a similar way to a switching power supply. A high switching frequency in the clocked LED driver allows the energy to be transferred from the input to the output with only minimal losses. Clocked LED driver ICs have very high efficiencies of well over 90%.

This allows the connected LED to be operated efficiently at its ideal operating point. The disadvantage of clocked LED drivers is the higher circuit complexity for the necessary interference suppression measures. This type of driver is therefore primarily of interest for LED lamps with high output and is therefore also one of the most expensive variants.

Linear LED drivers are typically used for LED vehicle tail lights, which have low power levels in contrast to LED vehicle headlights.

• zur Regelung und/oder Steuerung der Helligkeit bzw. Leuchtkraft der LEDs, beispielsweise durch eine pulsweitenmodulierte (PWM) Taktung der Stromversorgung für einen außerhalb des für das menschliche Auge wahrnehmbaren Bereichs gepulsten Betrieb,
• zur Kompensation oder Vermeidung elektromagnetischer Störungen, beispielsweise aufgebaut aus Kondensatoren und/oder Ferriten,
• zum Schutz der LEDs beispielsweise vor einer Überspannung des Bordnetzes oder vor fehlerhafter Polung, beispielsweise umfassend eine oder mehrere Zenerdioden.

For the sake of completeness, it should be mentioned that LEDs may also require additional electronic control circuits. Examples of these are electronic control circuits:

• for regulating and/or controlling the brightness or luminosity of the LEDs, for example by pulse width modulation (PWM) timing of the power supply for pulsed operation outside the range perceptible to the human eye,
• to compensate or avoid electromagnetic interference, for example constructed from capacitors and/or ferrites,
• to protect the LEDs, for example from overvoltage of the vehicle electrical system or from incorrect polarity, for example comprising one or more Zener diodes.

• einen Bordnetzanschluss zur Stromversorgung durch Anschluss an ein Bordnetz eines Fahrzeugs,
• einen Steuersignaleingang zum Anlegen eines eine Lichtfunktion steuernden Steuersignals in den LED-Treiber,
• einen mittels eines am Steuersignaleingang anliegenden Steuersignals schaltbaren LED-Konstantsromausgang, und
• einen LED-Ausfallsignalausgang zur Ausgabe eines Ausfallsignals auf. Darüber hinaus kann er einen PWM-Generator zur festen oder veränderlichen Einstellung der Lichtabstrahlung der an den LED-Konstantsromausgang angeschlossenen einen oder mehreren LEDs und damit der Helligkeit der durch sie verwirklichten Lichtfunktion aufweisen.

A modern LED driver for automotive applications already includes an electronic control circuit for LED failure detection. It has at least:

• an on-board power supply connection for power supply by connection to the on-board power supply of a vehicle,
• a control signal input for applying a control signal controlling a lighting function to the LED driver,
• an LED constant current output that can be switched by means of a control signal applied to the control signal input, and
• an LED failure signal output for outputting a failure signal. In addition, it can have a PWM generator for fixed or variable adjustment of the light emission of the one or more LEDs connected to the LED constant current output and thus the brightness of the lighting function implemented by them.

Multi-channel LED drivers for vehicle applications are also known, which, if necessary, by exploiting synergy effects, correspond to a number of LED drivers corresponding to the number of channels. Multi-channel LED drivers can comprise a programmable control unit, for example, to supply certain constant current outputs to the LEDs that fulfill various lighting functions or partial lighting functions or contribute to their fulfillment are connected or can be connected to realize realizable, recurring light sequences, such as a welcome light sequence when unlocking a vehicle or the like.

The provision of one luminous surface each to realize one lighting function is disadvantageous both from a design point of view and with regard to optimizing the installation space and weight of vehicles in general and vehicle lights in particular.

It is known, for example, to implement the tail light function and the brake light function on the same illuminated surface. The light sources illuminating the illuminated surface are supplied with a higher current when the brake light function is currently required than when the tail light function is currently required.

The disadvantage of this so-called bi-function is that when the tail light function is active, the brake light function can only be clearly recognized if the light surface used for the bi-function is constantly observed.

This results in reduced road safety.

One idea underlying the invention is to flank the luminous surface used to implement the bi-function by additional luminous surfaces, each assigned to only one of the two lighting functions implemented by the bi-function. At least one of the additional luminous surfaces is assigned to one lighting function, and at least one remaining additional luminous surface is assigned to the other lighting function of the two lighting functions implemented by the bi-function.

A difficulty associated with the use of LEDs is the implementation of the required LED failure detection in the concept underlying the invention.

This is due to the fact that if the failure of an LED in a lighting function implemented by LEDs is detected, this lighting function must be switched off completely.

If the luminous surfaces implementing two lighting functions overlap in an overlapping area comprising a common luminous surface, also known as a bi-light function luminous surface, it must be ensured that a defective lighting function in which a failure of an LED has been detected is switched off across the entire luminous surface intended for its implementation, whereas the remaining lighting function can still be activated.

In order to be able to use a diagnostic concept that implements LED failure detection in a vehicle light with a common luminous surface that is intended for two light functions that may additionally use their own luminous surfaces, preferably of the same light color but, for example, different luminous intensity, which diagnostic concept, in the case of LEDs as light sources, provides for the shutdown of the LED string that implements the respective light function in the event of a fault both for the common luminous surface and for the possibly additional one or more separate luminous surfaces, it is necessary to deactivate the common luminous surface only for the light function for which the presence of a fault was diagnosed.

However, if a fault is diagnosed in one of the lighting functions and the remaining lighting function is requested, it is desirable to continue to use the common light surface for the remaining lighting function and not to deactivate it.

This means that the bi-function light surface is preferably only switched off for both light functions if one LED of the bi-function light surface is actually defective.

Analogue electronic control circuits that implement this have limited robustness. Implementation using a microcontroller, on the other hand, is very costly. Robust implementation has so far been impossible without expensive logic controlled by a microprocessor.

One object of the invention is to provide a lighting device with a cost-effective LED control of two lighting functions of a vehicle lamp that are realized by overlapping lighting surfaces in a bi-light function lighting surface. which enables robust and reliable operation while contributing to increased road safety.

In particular, it is an object of the invention to provide a cost-effective lighting device with LED failure detection in conjunction with a bi-light function luminous surface.

Furthermore, it is an object of the invention to provide a vehicle lamp provided with a corresponding illuminant, which has at least two lighting functions overlapping one another in a bi-light function lighting surface.

An associated object of the invention can be seen as the provision of a cost-effectively implementable method for operating a lighting means with an LED control of two lighting functions for a vehicle light implemented by overlapping lighting surfaces in a bi-light function lighting surface.

The object is achieved by the features of the independent claim. Advantageous embodiments are reproduced in the claims, the drawings and in the following description, including that associated with the drawings.

A first subject of the invention therefore relates to a lighting device with several LEDs as light sources provided and/or contributing to the fulfillment of at least two lighting functions of a vehicle lamp realized within each of the lighting surfaces overlapping one another within an overlapping area forming a common lighting surface. The lighting device has an LED driver arrangement with integrated LED failure detection for the LEDs connected to each switchable output provided by a switchable constant current source. Each of the lighting functions is therefore preferably realized by a lighting surface that is made up of the common lighting surface and a separate lighting surface.

The LED driver arrangement has at least five switchable outputs, each providing a constant current source, and at least two inputs assigned to the switchable outputs. The switchable outputs are the LEDs connected to them, which are advantageously connected in series as LED strings to adapt to the voltage level, also referred to as LED constant current outputs. The inputs that can be connected to a control unit of a vehicle and are assigned to the switchable outputs are also referred to as control signal inputs. For example, the LED driver arrangement can have just as many inputs, each assigned to one of the switchable outputs. The LED driver arrangement also has a connection for the power supply, also referred to as an on-board power supply connection, intended for connection to an on-board power supply of a vehicle, and at least one LED failure signal output.

The LED driver arrangement can comprise several individual LED drivers, also called single-channel LED drivers. Alternatively or additionally, it can also comprise one or more multi-channel LED drivers.

• mindestens einen eine erste Stromstärke bereitstellender, erster Ausgang für den LED-Strang für die als Lichtquellen verwendeten LEDs der gegebenenfalls vorhandenen einen eigenen Leuchtfläche der einen Lichtfunktion,
• mindestens einen eine zweite Stromstärke, die doppelt so hoch ist, wie die erste Stromstärke bereitstellender zweiter Ausgang für den LED-Strang für die als Lichtquellen verwendeten LEDs der gegebenenfalls vorhandenen anderen eigenen Leuchtfläche der anderen Lichtfunktion, und
• mindestens drei jeweils die erste Stromstärke bereitstellende weitere Ausgänge, ein erster weiterer Ausgang, ein zweiter weiterer Ausgang und ein dritter weiterer Ausgang für den LED-Strang für die als Lichtquellen verwendeten LEDs der gemeinsamen Leuchtfläche.

The light source advantageously comprises at least one LED driver arrangement with separate inputs for the two light functions and several switchable outputs representing preset constant current sources, in short constant current outputs or LED constant current outputs. At least five outputs are provided. These are:

• at least one first output for the LED string providing a first current intensity for the LEDs used as light sources of the optionally present separate luminous surface of the one lighting function,
• at least one second output for the LED string for the LEDs used as light sources of the other separate luminous surface of the other lighting function, which output provides a second current which is twice as high as the first current, and
• at least three additional outputs, each providing the first current intensity, a first additional output, a second additional output and a third additional output for the LED string for the LEDs used as light sources of the common luminous surface.

The first output and the three other outputs are each designed as low-current constant current outputs, the second output is designed as a high-current constant current output.

The LED string of the individual light surface of a lighting function, if present, is connected to the first output.

The LED string of the other light surface of the other lighting function, if present, is connected to the second output.

The LED string of the common light area is connected to the three other outputs.

The outputs are controlled in such a way that when the first lighting function is requested, the first and the first additional outputs deliver a constant current of the first current strength, and when their current is delivered, the current output of the second additional output or the third additional output is interrupted.

If the LED string of one of the individual light areas or the shared light area fails, the first and the first additional output are switched off according to a provided diagnostic concept. This means that the first and the first additional output do not deliver any current even when the first light function is requested, which means that the interruption of the current delivery of the second additional output or the third additional output is cancelled when the second light function is requested at the same time.

Furthermore, the outputs are controlled in such a way that when the second lighting function is requested, the second output delivers a constant current of the second current strength and the second and third further outputs each deliver a constant current of the first current strength, which first current strengths add up to the second current strength through the LED string of the common light surface.

It is important to note that if the first light function is requested at the same time as the second light function, the current output of either the second or the third additional output is blocked. This can be interpreted as a priority switching that applies to a request for the first light function.

If the LED string of one of the individual light areas or the shared light area fails, the second output as well as the second and third additional outputs are switched off in accordance with the intended diagnostic concept.

After this, it is possible to operate the common light surface in accordance with the prescribed diagnostic concept without any further circuit logic.

By doubling the number of outputs per LED string and assigning two different current strengths to the outputs assigned to each light function, the light functions can also be operated at three different levels. A first weak level at one output with the first, weakest current strength, a second level at the other output with the second, double current strength, and a third level when both outputs are operated simultaneously with a third current strength, corresponding to three times the sum of the current strengths of one and the other output.

It is important to emphasize that the invention can be implemented by using not only one constant current output and associated control signal input combination, also referred to as a driver channel, for an LED driver arrangement with several outputs for connecting one LED string each for illuminating a luminous surface, which LED driver arrangement comprises several LED drivers and/or a multi-channel LED driver, for one LED string, but several, preferably at least three.

Further developments relate to LED failure detection and diagnosis and the associated LED string shutdown.

A second subject matter of the invention relates to a vehicle lamp equipped with such a lighting means with at least two lighting functions which overlap in a common lighting surface.

• der erste LED-Strang an einen eine erste Stromstärke bereitstellenden ersten Konstantstromausgang,
• der zweite LED-Strang an einen eine zweite Stromstärke, die doppelt so stark ist, wie die erste, bereitstellenden zweiten Konstantstromausgang, und
• der gemeinsame LED-Strang sowohl an einen dritten, als auch an einen vierten und an einen fünften, jeweils die erste Stromstärke bereitstellenden Konstantstromausgang

angeschlossen sind, und

• bei Anforderung der ersten Lichtfunktion durch ein an dem einem Eingang anliegendes Einschaltsignal am ersten und am dritten Ausgang,
• bei Anforderung der zweiten Lichtfunktion durch ein an dem verbleibenden Eingang anliegendes Einschaltsignal am zweiten, am vierten und am fünften Ausgang, und
• bei Anforderung beider Lichtfunktionen durch an beiden Eingängen anliegende Einschaltsignale am ersten, am zweiten, am vierten und am fünften Ausgang

jeweils Konstantstrom der jeweiligen Stromstärke abgegeben wird.The invention allows the realization of a vehicle lamp using a method for operating a vehicle lamp with LEDs as light sources of a luminous surface for realizing at least two light functions of the same light color but different brightness, with a first luminous surface serving to realize a first light function with a first LED string comprising at least one LED, a second luminous surface serving to realize a second light function with a second LED string comprising at least one LED, and with a second luminous surface serving to realize both the first and the second light function. common luminous surface with a common LED string comprising at least one LED, comprising an LED driver with at least two inputs each serving to supply a request signal for activating lighting functions and several constant current outputs, wherein:

• the first LED string to a first constant current output providing a first current,
• the second LED string to a second constant current output providing a second current that is twice as strong as the first, and
• the common LED string is connected to a third, a fourth and a fifth constant current output, each of which provides the first current intensity

are connected, and

• when the first light function is requested by a switch-on signal at one input at the first and third output,
• when the second light function is requested by a switch-on signal at the remaining input at the second, fourth and fifth outputs, and
• when both light functions are requested by switch-on signals at both inputs on the first, second, fourth and fifth outputs

A constant current of the respective current strength is delivered.

It is evident that the invention is realized by a surprising LED driver channel assignment in combination with a very specific parameterization of the LED driver.

It is also apparent that the invention provides a cost-effective and at the same time reliable solution for controlling LEDs provided as light sources for realizing at least two different lighting functions, preferably of the same light color, for example of different brightness, within a common luminous surface.

In order to be able to use a diagnostic concept for LED failure detection in a vehicle lamp with a common luminous surface, which is intended for two light functions of the same light colour but with different luminous intensity, which may also use their own luminous surfaces, which, in the case of LEDs as light sources, is applicable both for the common luminous surface and for the In addition, one or more separate luminous surfaces provide for the deactivation of the LED string implementing the respective lighting function in the event of an error, the invention makes it possible to deactivate the common luminous surface only for the lighting function for which the presence of an error was diagnosed.

However, if the remaining light function is requested when a fault is diagnosed in one light function, the invention allows the common light surface to continue to be used for the remaining light function, i.e. it does not have to be deactivated. Instead, the remaining light function can be operated with the constant current intended for it.

The advantages that arise beyond a complete solution to the task at hand while avoiding the disadvantages of the prior art are a significant savings potential, since no microcontroller is required for implementation. Likewise, no analog circuitry is required to implement the logic. The logic is parameterized in the LED driver. The invention enables a reduction in the number of components required. It also offers a technically robust and reliable solution. No additional software is required in the microcontroller. Fewer analog components, particularly semiconductors, are required to implement it.

The vehicle lamp can have individual features or a combination of the features described above and/or below in connection with the lighting device, just as the lighting device can have and/or implement individual features or a combination of several features described above and/or below in connection with the vehicle lamp.

The lighting means and/or the vehicle lamp can alternatively or additionally have individual features or a combination of several features described in the introduction in connection with the prior art and/or in one or more of the documents mentioned in the prior art and/or in the following description of the embodiments shown in the drawings.

Additional advantages over the prior art that go beyond the complete solution of the problem and/or the advantages mentioned above for the individual features are listed below.

Fig. 1

eine schematische Darstellung eines Ausführungsbeispiels eines Leuchtmittels mit mehreren LEDs als Lichtquellen für zweierlei Lichtfunktionen gleicher Lichtfarbe jedoch unterschiedlicher Helligkeiten mit Überschneidung der zu deren Verwirklichung vorgesehenen Leuchtflächen in einer gemeinsamen Leuchtfläche (Bi-Funktions-Leuchtfläche) einschließlich in Tab. 1 SL n-1 bzw. BL n-1 inklusiver Logiktabelle.

Fig. 2

eine schematische Darstellung eines Ausführungsbeispiels eines Leuchtmittels mit mehreren LEDs als Lichtquellen für zweierlei Lichtfunktionen gleicher Lichtfarbe jedoch unterschiedlicher Helligkeiten mit Überschneidung der zu deren Verwirklichung vorgesehenen Leuchtflächen in einer gemeinsamen Leuchtfläche (Bi-Funktions-Leuchtfläche) einschließlich in Tab. 2 SL n-1 bzw. BL SLM inklusiver Logiktabelle.

Fig. 3

ein Detail eines Ausführungsbeispiels eines Leuchtmittels mit 3-Pegel Lichtfunktion, wobei der als Kanal 1 bezeichnete Ausgang für einen Helligkeitspegel bei Nacht, der als Kanal 2 bezeichnete Ausgang für einen Helligkeitspegel bei Dämmerung und die beiden als Kanal 1 und 2 bezeichneten Ausgänge zusammen für einen Helligkeitspegel bei Tag vorgesehen sind.

The invention is explained in more detail below using embodiments shown in the drawing. The size ratios of the individual elements to one another in the figures do not always correspond to the actual size ratios, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration. Identical reference numerals are used for identical or equivalently acting elements of the invention. Furthermore, for the sake of clarity, only reference numerals are shown in the individual figures that are required for the description of the respective figure. The embodiments shown are merely examples of how the invention can be designed and do not represent a final limitation. They show in a schematic representation:

Fig.1

a schematic representation of an embodiment of a lighting means with several LEDs as light sources for two types of lighting functions of the same light color but different brightnesses with overlap of the luminous surfaces intended for their implementation in a common luminous surface (bi-function luminous surface) including in Tab. 1 SL n-1 or BL n-1 including logic table.

Fig.2

a schematic representation of an embodiment of a lighting means with several LEDs as light sources for two types of lighting functions of the same light color but different brightnesses with overlap of the luminous surfaces intended for their implementation in a common luminous surface (bi-function luminous surface) including in Tab. 2 SL n-1 or BL SLM including logic table.

Fig.3

a detail of an embodiment of a lamp with 3-level light function, wherein the output designated as channel 1 is intended for a brightness level at night, the output designated as channel 2 for a brightness level at dusk and the two outputs designated as channels 1 and 2 together for a brightness level during the day.

• mehrere LEDs 02 als Lichtquellen für zweierlei Lichtfunktionen vorteilhaft gleicher Lichtfarbe bevorzugt jedoch unterschiedlicher Helligkeiten mit Überschneidung der zu deren Verwirklichung vorgesehenen Leuchtflächen in einer auch als Bi-Funktions-Leuchtfläche bezeichneten, gemeinsamen Leuchtfläche,
• mindestens eine LED-Treiber-Anordnung 03 mit getrennten Eingängen 04 für Steuersignale zur Anforderung der beiden Lichtfunktionen, und
• mehrere jeweils voreingestellte Konstantstromquellen darstellende, schaltbare Ausgänge 05, kurz Konstantstromausgänge oder LED-Konstantstromausgänge, wobei vorzugsweise mindestens fünf Ausgänge 05 vorgesehen sind, an welche die den Lichtfunktionen zugeordneten LEDs 02, 21, 22, 23 oder LED-Stränge aus mehreren in Reihe angeordneten LEDs 02 der Leuchtflächen angeschlossen sind,

wobei zusätzlich zu an eigene erste und zweite Ausgänge 54, 55 angeschlossenen LEDs 22, 23 außerhalb der gemeinsamen Leuchtfläche liegender eigener Leuchtflächen, zumindest die LEDs 21 der gemeinsamen Leuchtfläche nicht nur an einen, sondern gleich parallel an mehrere, bevorzugt gleich drei weitere Ausgänge 51, 52, 53 gleichzeitig angeschlossen sind.A in Fig.1 , Fig.2 , Fig.3 Lamp 01 shown in whole or in part includes:

• several LEDs 02 as light sources for two different light functions, advantageously of the same light color but preferably of different brightnesses with overlap of the light surfaces intended for their implementation in a common light surface also referred to as a bi-function light surface,
• at least one LED driver arrangement 03 with separate inputs 04 for control signals to request the two lighting functions, and
• several switchable outputs 05, each representing preset constant current sources, in short constant current outputs or LED constant current outputs, wherein preferably at least five outputs 05 are provided, to which the LEDs 02, 21, 22, 23 assigned to the lighting functions or LED strings made up of several LEDs 02 of the luminous surfaces arranged in series are connected,

wherein, in addition to LEDs 22, 23 of separate luminous surfaces located outside the common luminous surface which are connected to separate first and second outputs 54, 55, at least the LEDs 21 of the common luminous surface are connected not only to one but in parallel to several, preferably three, further outputs 51, 52, 53 at the same time.

In other words, in addition to LEDs 22, 23 of separate luminous surfaces located outside the common luminous surface, which are connected to separate first and second outputs 54, 55, at least the LEDs 21 of the common luminous surface are connected to several further outputs 51, 52, 53.

It is important to emphasize that the invention can be implemented by using not only one LED constant current output and associated control signal input combination, also referred to as a driver channel, for an LED driver arrangement 03 with multiple outputs 04 for connecting an LED string used to illuminate a luminous surface, which LED driver arrangement 03 comprises multiple LED drivers and/or a multi-channel LED driver, for one LED string, but several, preferably at least three.

• jede der Lichtfunktionen vorzugsweise durch eine Leuchtfläche verwirklicht wird, die sich aus der gemeinsamen Leuchtfläche und jeweils einer eigenen Leuchtfläche zusammensetzt,
• an einen ersten Ausgang 54 die mindestens eine LED 22 oder der mindestens eine LED-Strang einer gegebenenfalls vorhandenen einen eigenen Leuchtfläche der einen Lichtfunktion angeschlossen ist,
• an einen zweiten Ausgang 55 die mindestens eine LED 23 oder der mindestens eine LED-Strang einer gegebenenfalls vorhandenen anderen eigenen Leuchtfläche der anderen Lichtfunktion angeschlossen ist,
• an drei weitere Ausgänge 51, 52, 53 die mindestens eine LED 21 oder der mindestens eine LED-Strang der gemeinsamen Leuchtfläche angeschlossen ist,
• der erste Ausgang 54 und die drei weiteren Ausgänge 51, 52, 53 jeweils als niederbestromte Konstantstromausgänge, und der zweite Ausgang 55 als hochbestromter Konstantstromausgang ausgelegt sind,
• bei Anforderung der einen Lichtfunktion der erste Ausgang 54 und der erste weitere Ausgang 51 eingeschaltet sind und bei eingeschaltetem ersten Ausgang 54 und eingeschaltetem ersten weiteren Ausgang 51 eine Stromabgabe des zweiten weiteren Ausgangs 52 oder des dritten weiteren Ausgangs 53 immer, das heißt beispielsweise sowohl bei Anforderung der einen Lichtfunktion, als auch bei gleichzeitiger Anforderung der anderen Lichtfunktion unterbrochen ist, und
• bei Anforderung der anderen Lichtfunktion der zweite Ausgang 55 und der zweite weitere Ausgang 52 sowie der dritte weitere Ausgang 53 unter der Maßgabe eingeschaltet sind, dass bei gleichzeitiger Anforderung der einen Lichtfunktion einhergehend mit eingeschaltetem ersten Ausgang 54 und eingeschaltetem ersten weiteren Ausgang 51 die Stromabgabe des zweiten weiteren Ausgangs 52 oder des dritten weiteren Ausgangs 53 unterbrochen ist, wobei
• die Stromabgabe des zweiten weiteren Ausgangs 52 oder des dritten weiteren Ausgangs 53 bei eingeschaltetem ersten Ausgang 54 und eingeschaltetem ersten weiteren Ausgang 51 und gleichzeitiger Anforderung der anderen Lichtfunktion unterbrochen ist,

so dass sich die Stromabgaben durch die an die niederbestromten weiteren Ausgänge 51, 52, 53 angeschlossenen LEDs 21 bei Anforderung der anderen Lichtfunktion unabhängig davon, ob der erste 54 und erste weitere Ausgang 51 eingeschaltet ist oder nicht, zu einem der Stromabgabe des hochbestromten Ausgangs (hier: des zweiten Ausgangs 55) entsprechenden Gesamtstrom addieren.An advantageous development relates to a light source 01 with several LEDs 02 as light sources for two types of light functions of the same light color but different brightnesses with overlap of the light surfaces provided for their implementation in a common light surface (bi-function light surface), comprising at least one LED driver arrangement 03 with separate inputs 04 for control signals for requesting the two light functions and several switchable outputs 05 each representing preset constant current sources, in short constant current outputs or LED constant current outputs, wherein at least five outputs 05 are provided to which the LEDs 02 assigned to the light functions or LED strands made up of several LEDs 02 of the light surfaces arranged in series are connected, wherein:

• each of the lighting functions is preferably implemented by a luminous surface, which consists of the common luminous surface and a separate luminous surface,
• the at least one LED 22 or the at least one LED string of a possibly existing separate luminous surface of the one lighting function is connected to a first output 54,
• the at least one LED 23 or the at least one LED string of a possibly existing other separate luminous surface of the other lighting function is connected to a second output 55,
• at least one LED 21 or at least one LED string of the common light surface is connected to three further outputs 51, 52, 53,
• the first output 54 and the three other outputs 51, 52, 53 are each designed as low-current constant current outputs, and the second output 55 is designed as a high-current constant current output,
• when one light function is requested, the first output 54 and the first further output 51 are switched on and when the first output 54 and the first further output 51 are switched on, the current output of the second further output 52 or the third further output 53 is always interrupted, i.e., for example, both when one light function is requested and when the other light function is requested at the same time, and
• when the other light function is requested, the second output 55 and the second further output 52 as well as the third further output 53 are switched on, provided that when the one light function is requested simultaneously with the first output 54 and the first further output 51 switched on, the current output of the second further output 52 or the third further output 53 is interrupted, whereby
• the current output of the second additional output 52 or the third additional output 53 is interrupted when the first output 54 and the first additional output 51 are switched on and the other light function is requested at the same time,

so that the current outputs by the LEDs 21 connected to the low-current additional outputs 51, 52, 53 add up to a total current corresponding to the current output of the high-current output (here: the second output 55) when the other lighting function is requested, regardless of whether the first 54 and first additional output 51 are switched on or not.

• mindestens ein niederbestromter, eine erste Stromstärke bereitstellender, erster Ausgang 54 für den LED-Strang für die als Lichtquellen verwendeten LEDs 22 der gegebenenfalls vorhandenen einen eigenen Leuchtfläche der einen Lichtfunktion,
• mindestens ein hochbestromter, eine zweite Stromstärke, die bevorzugt doppelt so hoch ist, wie die erste Stromstärke bereitstellender zweiter Ausgang 55 für den LED-Strang für die als Lichtquellen verwendeten LEDs 23 der gegebenenfalls vorhandenen anderen eigenen Leuchtfläche der anderen Lichtfunktion, und
• mindestens drei niederbestromte, jeweils die erste Stromstärke bereitstellender weitere Ausgänge 51, 52, 53, ein erster weiterer Ausgang 51 , ein zweiter weiterer Ausgang 52 und ein dritter weiterer Ausgang 53 für den LED-Strang für die als Lichtquellen verwendeten LEDs 21 der gemeinsamen Leuchtfläche

vorgesehen.The light source 01 advantageously comprises at least one LED driver arrangement 03 with separate inputs 04 for the two light functions and several switchable outputs 05, each representing preset constant current sources, in short constant current outputs or LED constant current outputs. At least five outputs are:

• at least one low-current, first output 54 providing a first current intensity for the LED string for the LEDs 22 used as light sources of the optionally present separate luminous surface of the one lighting function,
• at least one high-current second output 55 for the LED string for the LEDs 23 used as light sources of the other separate luminous surface of the other light function, which may be present, providing a second current intensity which is preferably twice as high as the first current intensity, and
• at least three low-current additional outputs 51, 52, 53, each providing the first current intensity, a first additional output 51, a second additional output 52 and a third additional output 53 for the LED string for the LEDs 21 used as light sources of the common luminous surface

provided.

The outputs 05 are controlled in such a way that when the first light function is requested, the first 54 and the first additional output 51 deliver a constant current of a first, low current intensity, and a current output of the second additional output 52 or the third additional output 53 is always blocked when the first 54 and the first additional output 51 are switched on.

Furthermore, the outputs 05 are controlled in such a way that when the second lighting function is requested, the second output 55 delivers a constant current of a second, high current strength and the second 52 and the third further output 53 each deliver a constant current of the first current strength, which first current strengths add up to the second current strength through the LED string of the common light surface.

It is important to note that if the first light function is requested at the same time as the second light function and the first 54 and the first additional output 51 are switched on, the current output of either the second 52 or the third additional output 53 is blocked, i.e. interrupted, even if the second 52 and the third additional output 53 are switched on due to a request for the other light function. This can be interpreted as a priority switching that applies to a request for the first light function.

If one light function and the other light function are required at the same time, the Fig.1 The priority requirement reproduced in Table 1 is that when one light function is requested, current output from the second additional output 52 or the third additional output 53 is blocked (channel 3 assigned to the third additional output 53 is set to 0 mA when a light function designed as a tail light SL is requested at the same time as the other light function designed as a brake light BL). In this case, the first additional output 51 outputs a constant current of low current intensity, which is then added together with the constant current of low current intensity of the non-blocked, remaining third 53 or second additional output 52 to form a constant current of high current intensity.

It is important to emphasize at this point that the previously made statements about an interruption or blockage of the current output of the second additional output 52 or the third additional output 53 when the first output 54 and the first additional output 51 are switched on initially refer to can be interpreted that the rule of interrupting or blocking the power output of the second additional output 52 or the third additional output 53 applies when the first lighting function is requested. The special formulation depending on the first output 54 being switched on and the first additional output 51 being switched on is, however, of importance with regard to a preferred embodiment of the invention described below, which is related to LED failure detection and a diagnostic concept or the associated shutdown of the first output 54 and the first additional output 51 in the event of failure of the LED 02 or the LED string of the one separate lighting surface 22 or the shared lighting surface 21. This embodiment not only provides for a dependency on a request for the lighting functions, but also prescribes a shutdown of outputs for the diagnostic concept when an LED failure is detected, which is independent of the request for lighting functions. This is necessary in order to be able to carry out a prescribed shutdown of one light function, for example if a failure of an LED 22 of a separate light surface of one light function is detected, without this affecting the common light surface when the other light function is implemented.

For the sake of completeness, it should be mentioned that the expressions "a lighting function", "another lighting function", "a separate luminous surface" and "another separate luminous surface" are synonymous with the expressions "first lighting function", "second lighting function", "first separate luminous surface" and "second separate luminous surface" used elsewhere in this document.

In order to be able to carry out LED failure detection, the light source 01 advantageously comprises means for LED failure detection integrated, for example, in the LED driver arrangement 03. In this context, the light source can have an LED failure signal output.

This subject matter of the invention therefore comprises a previously described illuminant 01 with several LEDs 02 as light sources provided and/or contributing to the fulfillment of at least two light functions of a vehicle light realized within each of the luminous surfaces overlapping one another within an overlapping area forming a common luminous surface, also referred to as a bi-functional luminous surface. The illuminant 01 has an LED driver arrangement 03 with LED failure detection preferably integrated in the LED driver arrangement 03 for the LEDs 02, 21, 22, 23 connected to each LED constant current output provided by a switchable constant current source.

Advantageously, according to a provided diagnostic concept, when a failure of an LED 22 or an LED string of a separate luminous surface or of an LED 21 or an LED string of the common luminous surface is detected, the first output 54 and the first further output 51 are switched off.

Also advantageously, according to the intended diagnostic concept, if a failure of an LED 23 or an LED string of the other separate luminous surface or an LED 21 or an LED string of the common luminous surface is detected, the second output 55 as well as the second further output 52 and the third further output 53 are switched off.

After this, it is possible to operate the common light surface in accordance with the prescribed diagnostic concept without any further circuit logic.

• getrennten Steuersignaleingängen 04 für die beiden Lichtfunktionen anfordernde Steuersignale,
• mindestens fünf den Steuersignaleingängen zugeordnete jeweils eine Konstantstromquelle bereitstellenden schaltbaren LED-Konstantstromausgängen, und
• integrierter LED-Ausfallerkennung für die an jeden durch jeweils eine schaltbare Konstantstromquelle bereitgestellten LED-Konstantstromausgang angeschlossenen LEDs 21, 22, 23.

It is apparent that this subject matter of the invention is achieved by a Fig.2 illustrated illuminant 01 with several LEDs 02 as light sources for two types of lighting functions with overlap of the luminous surfaces intended for their implementation in a common luminous surface (bi-function luminous surface), comprising the common luminous surface and two LEDs 02, 21, 22, 23 assigned to one of the two lighting functions and other separate luminous surfaces or LED strands made up of several LEDs 02 arranged in series, an LED driver arrangement 03 with:

• separate control signal inputs 04 for the two light functions requesting control signals,
• at least five switchable LED constant current outputs, each providing a constant current source, assigned to the control signal inputs, and
• integrated LED failure detection for the LEDs 21, 22, 23 connected to each LED constant current output provided by a switchable constant current source.

• mindestens einen eine erste Stromstärke bereitstellenden, ersten LED-Konstantstromausgang, an den die LEDs 22 der der einen Lichtfunktion zugeordneten einen eigenen Leuchtfläche angeschlossen sind,
• mindestens einen eine zweite Stromstärke, die doppelt so hoch ist, wie die erste Stromstärke bereitstellenden zweiten LED-Konstantstromausgang, an den die LEDs 23 der der anderen Lichtfunktion zugeordneten anderen eigenen Leuchtfläche angeschlossen sind, und
• mindestens drei jeweils die erste Stromstärke bereitstellende weitere LED-Konstantstromausgänge, ein erster weiterer LED-Konstantstromausgang, ein zweiter weiterer LED-Konstantstromausgang und ein dritter weiterer LED-Konstantstromausgang, an welche die LEDs 21 der beiden Lichtfunktionen zugeordneten gemeinsamen Leuchtfläche alle gleichzeitig parallel angeschlossen sind,

wobei die LED-Konstantstromausgänge wie in Tab. 2 in Fig. 2 dargestellt derart angesteuert sind, dass:

• bei Anforderung der einen Lichtfunktion der erste Ausgang 54 und der erste weitere Ausgang 51 Konstantstrom der ersten Stromstärke abgeben, und bei eingeschaltetem ersten Ausgang 54 und eingeschaltetem ersten weiteren Ausgang 51 eine Stromabgabe des zweiten weiteren Ausgangs 52 oder des dritten weiteren Ausgangs 53 unterbrochen und dadurch blockiert ist, und
• bei Anforderung der anderen Lichtfunktion der zweite Ausgang 55 Konstantstrom der zweiten Stromstärke und der zweite weitere Ausgang 52 und der dritte weitere Ausgang 53 jeweils Konstantstrom der ersten Stromstärke abgeben, welche ersten Stromstärken sich zur zweiten Stromstärke durch die LEDs 21 der gemeinsamen Leuchtfläche addieren,
• wobei bei zusätzlicher gleichzeitiger Anforderung der einen Lichtfunktion der erste Ausgang 54 und der erste weitere Ausgang 51 eingeschaltet sind und eine Stromabgabe des zweiten weiteren Ausgangs 52 oder des dritten weiteren Ausgangs 53 blockiert ist und sich die ersten Stromstärken der beiden in diesem Fall aktiven weiteren Ausgänge 51, 52, 53, nämlich dem ununterbrochenen ersten weiteren Ausgang 51 und dem zweiten weiteren Ausgang 52 beziehungsweise dem ersten weiteren Ausgang 51 und dem dritten weiteren Ausgang 53 durch die an die weiteren Ausgänge 51, 52, 53 angeschlossenen LEDs 21 der gemeinsamen Leuchtfläche bei Anforderung der anderen Lichtfunktion unabhängig davon, ob die eine Lichtfunktion angefordert ist, oder nicht, zu einem der zweiten Stromstärke entsprechenden Gesamtstrom addieren, und
• wobei bei Erkennung eines Ausfalls einer LED 21, 22 der einen Lichtfunktion der erste Ausgang 54 und der erste weitere Ausgang 51 abgeschaltet sind und dadurch eine Stromabgabe des zweiten weiteren Ausgangs 52 oder des dritten weiteren Ausgangs 53 selbst bei Anforderung der einen Lichtfunktion ununterbrochen und nicht blockiert ist und sich die ersten Stromstärken der beiden in diesem Fall aktiven weiteren Ausgänge 52, 53, nämlich dem ununterbrochenen zweiten weiteren Ausgang 52 und dem dritten weiteren Ausgang 53 durch die parallel gleichzeitig sowohl an den zweiten weiteren Ausgang 52 als auch an den dritten weiteren Ausgang 53 angeschlossenen LEDs 21 der gemeinsamen Leuchtfläche bei Anforderung der anderen Lichtfunktion unabhängig davon, ob die eine Lichtfunktion angefordert ist, oder nicht, zu einem der zweiten Stromstärke entsprechenden Gesamtstrom addieren.

Such a light source 01 is characterized by

• at least one first LED constant current output providing a first current intensity, to which the LEDs 22 of the separate luminous surface assigned to the one lighting function are connected,
• at least one second LED constant current output providing a second current intensity that is twice as high as the first current intensity, to which the LEDs 23 of the other separate luminous surface assigned to the other lighting function are connected, and
• at least three additional LED constant current outputs each providing the first current intensity, a first additional LED constant current output, a second additional LED constant current output and a third additional LED constant current output, to which the LEDs 21 of the common light surface assigned to both light functions are all connected in parallel at the same time,

where the LED constant current outputs are as shown in Tab. 2 in Fig.2 shown are controlled in such a way that:

• when one of the light functions is requested, the first output 54 and the first further output 51 deliver a constant current of the first current intensity, and when the first output 54 and the first further output 51 are switched on, a current output of the second further output 52 or the third further output 53 is interrupted and thereby blocked, and
• when the other light function is requested, the second output 55 delivers a constant current of the second current strength and the second further output 52 and the third further output 53 each deliver a constant current of the first current strength, which first current strengths add up to the second current strength through the LEDs 21 of the common light surface,
• wherein, in the case of an additional simultaneous request for one light function, the first output 54 and the first further output 51 are switched on and a current output of the second further output 52 or the third further output 53 is blocked and the first current intensities of the two additional outputs 51, 52, 53 active in this case, namely the uninterrupted first further output 51 and the second further output 52 or the first further output 51 and the third further output 53, are switched on by the LEDs 21 of the common light surface connected to the additional outputs 51, 52, 53 when requested the other light function, regardless of whether one light function is requested or not, to a total current corresponding to the second current, and
• wherein, upon detection of a failure of an LED 21, 22 of one lighting function, the first output 54 and the first further output 51 are switched off and as a result a current output of the second further output 52 or the third further output 53 is uninterrupted and not blocked even when the one lighting function is requested, and the first current intensities of the two further outputs 52, 53 that are active in this case, namely the uninterrupted second further output 52 and the third further output 53, are added to a total current corresponding to the second current intensity by the LEDs 21 of the common luminous surface that are connected in parallel to both the second further output 52 and the third further output 53 when the other lighting function is requested, regardless of whether the one lighting function is requested or not.

The light source 01 can also advantageously have or include an on-board power supply connection integrated, for example, in the LED driver arrangement 03.

The LED driver arrangement 03 therefore has at least five switchable outputs 05, each providing a constant current source, and at least two inputs 04 assigned to the switchable outputs. The switchable outputs 05 are also referred to as LED constant current outputs because of the LEDs 02 connected to them, which are advantageously connected in series as LED strands to adapt to the voltage level. The inputs 04 assigned to the switchable outputs 05, which can be connected to a control unit of a vehicle, are also referred to as control signal inputs. For example, the LED driver arrangement 03 can have just as many inputs 04, each assigned to one of the switchable outputs 05. Furthermore, the light source 01, for example the LED driver arrangement 03, has a connection for the power supply, also referred to as an on-board power supply connection, intended for connection to an on-board power supply of a vehicle and, if necessary, at least one LED failure signal output.

The LED driver arrangement 03 can comprise several individual LED drivers, also called single-channel LED drivers. Alternatively or additionally, it can also comprise one or more multi-channel LED drivers.

One in Fig.3 The advantageous further development of the light source 01 shown provides that the LED driver arrangement 03 of the light source with a double number of outputs 05 for the LEDs 21, 22, 23 or LED strands assigned to the separate light surfaces and the common light surface, wherein the LEDs 21, 22, 23 of the light surfaces are connected to respective double outputs 57 in addition to the first output 54, the second output 55 and the three further outputs 51, 52, 53 comprising simple outputs 56 to which they are already connected, which each output their own, for example higher, preferably double, or for example weaker, preferably half, current intensity than the respective simple outputs 56 in order to operate the lighting functions, for example depending on the visibility and/or ambient brightness, with for example three different brightness levels each.

By doubling the number of outputs 05 per LED string and assigning two different current strengths to the respective outputs 56, 57 assigned to a lighting function, the lighting functions can also be operated with three different brightness levels. A first weak level on one, for example single output 56 with the first, weakest current strength, a second level on the other, for example double output 57 with the second, double current strength, and a third level when both outputs 56, 57 are operated simultaneously with a third current strength, triple the sum of the current strengths of one and the other output 56, 57.

Such a light source 01 advantageously has at least one brightness level control signal input 06.

The LED driver arrangement 03 of the light source 01 advantageously comprises one or more linear LED drivers. These are cost-effective electronic assemblies with a reasonably high level of efficiency, i.e. a reasonable power loss, particularly in rear light applications.

The LED driver arrangement 03 of the light source can alternatively or additionally comprise one or more PWM generators (PWM; pulse width modulation) for regulating and/or controlling the brightness or luminosity of the LEDs 02 by means of a pulse width modulated clocking of the power supply for a pulsed operation outside the range perceptible to the human eye.

It is advantageous if the PWM generator or the PWM generators are operated in push-pull mode at the low-current outputs 51, 52, 53, 54, 56 which add up to a high current.

• zum Einen können die Stromstärken beispielsweise zweier an ein und dieselben LEDs angeschlossener niederbestromter Ausgänge bei gleichzeitigem Einschalten der betroffenen niederbestromten Ausgänge addiert werden, sowohl mit, als auch ohne PWM-Generator.
• zum Anderen können bei vorhandenem PWM-Generator die Stromversorgungen der betroffenen niederbestromten Ausgänge derart gegenläufig getaktet werden, dass die Strompulse des einen niederbestromten Ausgangs in die Pausen zwischen aufeinanderfolgenden Strompulsen des anderen niederbestromten Ausgangs fallen.

Durch beide Maßnahmen wird die Lichtabstrahlung, i.e. Helligkeit der an beide betroffenen niederbestromten Ausgänge 51, 52, 53, 54, 56 angeschlossenen LEDs 02 erhöht.Basically, there are two ways to generate a high current supply of high-current LEDs while simultaneously requiring both lighting functions to emit bright light:

• On the one hand, the current strengths of, for example, two low-current outputs connected to one and the same LEDs can be added when the low-current outputs in question are switched on at the same time, both with and without a PWM generator.
• On the other hand, if a PWM generator is present, the power supplies of the affected low-current outputs can be clocked in opposite directions such that the current pulses of one low-current output fall into the pauses between successive current pulses of the other low-current output.

Both measures increase the light emission, ie brightness, of the LEDs 02 connected to both affected low-current outputs 51, 52, 53, 54, 56.

A second subject matter of the invention relates to a vehicle lamp equipped with such a light source 01 with at least two lighting functions which overlap in a common luminous surface.

For example, this is a vehicle lamp with a lamp interior that is at least partially enclosed by a lamp housing with at least one light opening and a light disc that closes this, and at least one light source accommodated therein that includes several LEDs 02 as light sources for at least two when looking from outside the lamp interior at the light disc or through it by means of Lighting functions of the vehicle lamp realized by at least one common luminous surface (bi-functional luminous surface) of overlapping luminous surfaces, comprising a lighting means 01 as described above.

The vehicle lamp is preferably designed as a rear lamp for a motor vehicle.

• der erste LED-Strang an einen eine erste Stromstärke bereitstellenden ersten Konstantstromausgang,
• der zweite LED-Strang an einen eine zweite Stromstärke, die doppelt so stark ist, wie die erste, bereitstellenden zweiten Konstantstromausgang, und
• der gemeinsame LED-Strang sowohl an einen dritten, als auch an einen vierten und an einen fünften, jeweils die erste Stromstärke bereitstellenden Konstantstromausgang

angeschlossen sind, und

• bei Anforderung der ersten Lichtfunktion durch ein an dem einem Eingang anliegendes Einschaltsignal am ersten und am dritten Ausgang,
• bei Anforderung der zweiten Lichtfunktion durch ein an dem verbleibenden Eingang anliegendes Einschaltsignal am zweiten, am vierten und am fünften Ausgang, und
• bei Anforderung beider Lichtfunktionen durch an beiden Eingängen anliegende Einschaltsignale am ersten, am zweiten, am vierten und am fünften Ausgang

jeweils Konstantstrom der jeweiligen Stromstärke abgegeben wird.The invention allows the realization of a vehicle light using a method for operating a vehicle light with LEDs as light sources of a luminous surface for realizing at least two light functions of the same light color but different brightness, with a first luminous surface serving to realize a first light function with a first LED string comprising at least one LED, a second luminous surface serving to realize a second light function with a second LED string comprising at least one LED, and with a common luminous surface serving to realize both the first and the second light function with a common LED string comprising at least one LED, comprising an LED driver with at least two inputs each serving to supply a request signal for activating light functions and several constant current outputs, wherein:

• the first LED string to a first constant current output providing a first current,
• the second LED string to a second constant current output providing a second current that is twice as strong as the first, and
• the common LED string is connected to a third, a fourth and a fifth constant current output, each of which provides the first current intensity

are connected, and

• when the first light function is requested by a switch-on signal at one input at the first and third output,
• when the second light function is requested by a switch-on signal at the remaining input at the second, fourth and fifth outputs, and
• when both light functions are requested by switch-on signals at both inputs on the first, second, fourth and fifth outputs

A constant current of the respective current strength is delivered.

Further advantageous embodiments of such a method emerge from the above description for controlling the outputs 05 of the LED driver arrangement 03 of the light source 01. This makes it possible to realize a light signature with bi-function, for example tail light/brake light (SUBL) cost-effectively.

The bi-function is an LED string that can be operated at tail light and brake light level, for example.

Bi-functions such as tail light (SL) and brake light (BL) implemented on a bi-function light surface flanked by separate light surfaces in combination with pure SL and/or BL LEDs 22, 23 are increasingly in demand. In particular, a special logic is required for the implementation of the diagnostic behavior depending on the diagnostic concept. In order to avoid implementing this using expensive and unreliable analog circuitry or an additional intelligent component such as a microcontroller, a very specific channel assignment and parameterization of an LED driver arrangement 03 is used to implement the required logic for the diagnostic behavior.

A possible diagnostic concept looks like this: SL is subject to the so-called n-1 criterion, which states that if one SL LED string fails, the remaining SL LED strings should remain activated. BL is subject to the Single Lamp Mode (SLM), which states that if one BL string fails, all other BL strings should also be deactivated. The same concept applies to the bi-function LED strings. In addition, if one BL string fails and SL is requested, the bi-function with SL level should remain activated for the bi-function. This additional complexity can be realized using a very specific electronic connection of the LED strings to the LED driver, as well as the parameterization of the intelligent LED drivers, which ultimately reflects the inventive feature.

This very specific electronic connection of the LED driver arrangement 03 consists, on the one hand, in the fact that not only one LED driver channel is used to control an LED 21 or an LED string of the bi-function light surface, but, depending on the diagnostic concept, two or more driver channels are used in parallel. The LED driver arrangement 03 is parameterized in such a way that the driver channels for the corresponding bi-function, depending on the requested light function, use the driver channel activated or deactivated. The prioritization of the switching signals SL/BL is also relevant here, as explained below.

It is essential for the LED driver arrangement 03 to be able to operate it in what is known as stand-alone mode. This means that the LED driver arrangement 03 has a signal input in order to be able to process the information "SL activation" and "BL activation". Ideally, the SL or BL activation can be prioritized relative to one another. The LED driver arrangement 03 preferably has one or more internal diagnostic groups in order to be able to operate a freely configurable part of the LED driver channels in single lamp mode, or SLM for short, or in multi lamp mode, or n-1 criterion for short. The currents of the respective LED driver channels can preferably be individually parameterized.

Furthermore, a 3-level light function can be implemented using several driver channels for an LED string, as shown in Fig.3 explained in more detail.

A development challenge is to implement the diagnostic concept/failure detection concept, especially for the bi-function, as a certain logic/intelligence is required here. Example: If an LED error is detected in the other light function, for example implemented as the brake light function BL, which cannot be compensated for by the remaining LEDs that may still be available to the other light function, then all BL LEDs must be deactivated (so-called single lamp mode - SLM). This also entails the requirement that the bi-function light surface should also be deactivated. However: If the light function SL, for example implemented as the tail light function SL, is requested, then the bi-function light surface should be activated again, with the corresponding SL light or brightness level.

This if-error logic "then off, but if SL requested then on (IF-Else)" can currently be implemented either with an expensive microcontroller or with a complex analog circuit comprising several transistors and/or diodes, thus resulting in an expensive and not very robust concept.

The invention provides a surprising and at the same time cost-effective solution for the realization of this if-error logic.

In Fig.1 and in connection with Fig.1 In Table 1 shown, a lamp 01 is shown which fulfils a bi-function with a so-called n-1 criterion for a light function designed as a tail light function, or tail light SL for short, and another light function designed as a brake light function, or brake light BL for short.

For example, pure SL should be operated with 10mA and pure BL with 20mA. Furthermore, the bi-function light area LED string should be 10mA when SL is requested, 20mA when BL and also 20mA when SL&BL. Both functions are subject to the n-1 criterion. This means that if one LED string fails, the other LED strings of the function remain active.

To implement the bi-function, in this embodiment, three driver channels provided by the additional outputs 51, 52, 53 are required for each bi-function light area. For pure SL or pure BL, only one driver channel provided by the first output 54 or the second output 55 is required, cf. Fig.1 .

On the input side, the switching signals from SL and BL are shown schematically via the inputs 04 IN 0 and IN 1 respectively. IN 0 has a higher priority than IN 1.

The parameterization of the LED driver arrangement 03 is such that when the SL is activated via IN 0, for example 10 mA flows via driver channels 1 and 4, corresponding to the first additional output 51 and the first output 54. Thus, pure SL and bi-function have the required SL current level.

If only BL is requested, 10mA flows through driver channel 2 and driver channel 3, corresponding to the second additional output 52 and the third additional output 53, and 20mA flows through driver channel 5, corresponding to the second output 55. Pure BL therefore has 20mA and the bi-function also has a total of 20mA. BL level is reached.

If SL and BL are requested, 10mA flows through driver channel 1 and driver channel 3 and driver channel 4, corresponding to the first additional output 51, the third additional output 53 and the first output 54, and 20mA flows through driver channel 5, corresponding to the second output 55. For the LED 21 or the The total LED string of the bi-function light area is 20mA. For SL 10mA, for BL 20mA. Since SL is requested and has a higher priority than BL, 0mA flows through driver channel 2, corresponding to the second additional output 52. The current output of the second additional output 52 is then interrupted if SL is requested at the same time as BL.

Regarding failure behavior, no SLM is defined for the n-1 criterion. In the event of an LED failure, the remaining LED strings of the respective lighting function remain on.

In Fig.2 and in connection with Fig.2 In Table 2 reproduced, a bi-function with a so-called n-1 criterion for a light function designed as a tail light function, or tail light SL for short, and SLM for another light function designed as a brake light function, or brake light BL for short, is shown.

This embodiment behaves like the previous embodiment in terms of driver channel assignment and current setting. The difference can be found in the diagnostic setting of the LED driver arrangement 03. The corresponding BL driver channels are combined in a diagnostic group and operated in the SLM.

As shown in Table 2, the driver channels 2, 3, 5, the second additional output 52, the third additional output 53 and the second output 55 are combined in the diagnostic group (diag. group) BL. If a BL LED string fails, the remaining BL LED strings are deactivated. In particular, LED 21 or the LED string of the bi-function light area behaves as required by deactivating the BL-relevant driver channels. However, if SL is also requested, the SL level of 10mA is still reached. The same correct behavior is achieved even if a bi-function string were to exhibit an error.

In Fig.3 and in connection with Fig.3 Table 3 shows a lamp 01 that fulfills a 3-level lighting function.

In Fig.3 A possible configuration of a 3-level light function is shown. The three levels refer to the three adjustable brightness or light levels, for example, to adjust the light intensity to day/dusk/night. Two driver channels, corresponding to a single output 56 and a double output 57, are preferably used for this. One driver channel, corresponding to the single output 56, drives a low current for the night level. The other driver channel, corresponding to the double output 57, drives a medium current for the twilight level. If both driver channels, corresponding to both the single output 56 and the double output 57, are activated at the same time, the currents are added and the day level is reached. Optionally, the driver channels can be assigned to a diagnostic group in order to be operated in the SLM.

The 3-level light function is preferably implemented with one LED driver, particularly preferably within the LED driver arrangement 03. However, it would also be conceivable to implement the 3-level light function or generally a multi-level light function with two or more LED drivers or using one or more multi-channel LED drivers.

The lighting means 01, like the vehicle lamp, can alternatively or additionally have individual features or a combination of several features mentioned in the introduction in connection with the prior art and/or in one or more of the documents mentioned in the prior art and/or in the description below.

The invention can alternatively or additionally be implemented by or in connection with a method which can have individual or combinations of the features described for the lighting means 01 and/or the vehicle lamp and/or method steps implementing these and/or implemented by them.

The invention is not limited by the description based on the embodiments. Rather, the invention includes any new feature and any combination of features, which in particular includes any combination of features in the claims, even if this feature or this combination itself is not explicitly stated in the claims or embodiments.

The invention is particularly applicable commercially in the field of manufacturing vehicle lights, in particular motor vehicle lights.

The invention has been described with reference to preferred embodiments. However, it will be apparent to a person skilled in the art that modifications or variations of the invention may be made without departing from the scope of the following claims.

List of reference symbols

01

Lamps

02

LED

03

LED driver arrangement

04

Entrance

05

Exit

06

Brightness level control signal input

21

LED of the common light area

22

LED with its own light surface

23

LED of the other own light area

51

first further exit

52

second further exit

53

third additional exit

54

first exit

55

second exit

56

easy exit

57

double output

Claims (15)

Illuminant (01) with multiple LEDs (02) as light sources for two types of lighting functions with overlap of the luminous surfaces provided for their implementation in a common luminous surface (bi-function luminous surface), comprising at least one LED driver arrangement (03) with separate inputs (04) for control signals for requesting the two lighting functions and multiple switchable outputs (05) each representing preset constant current sources, to which the LEDs (02) or LED strands made up of multiple LEDs (02) arranged in series are connected, wherein at least the LEDs (21) of the common luminous surface are connected in parallel to multiple outputs (51, 52, 53). Illuminant according to claim 1, wherein each of the lighting functions is realized by a luminous surface which is composed of the common luminous surface and a respective individual luminous surface. Illuminant according to claim 1 or 2, wherein: - to a first output (54) the at least one LED (22) of a separate luminous surface of a lighting function is connected, - at least one LED (23) of another separate luminous surface of the other lighting function is connected to a second output (55), - at least one LED (21) of the common light surface is connected to three further outputs (51, 52, 53), - the first output (54) and the three further outputs (51, 52, 53) are each designed as low-current constant current outputs, and the second output (55) is designed as a high-current constant current output, - when one of the light functions is requested, the first (54) and the first additional output (51) are switched on and when the first (54) and the first additional output (51) are switched on, the current output of the second additional output (52) or the third additional output (53) is always interrupted, and - when the other lighting function is requested, the second output (55) and the second (52) as well as the third additional output (53) are switched on. A lighting device according to claim 1, 2 or 3, comprising means for LED failure detection. Illuminant according to claim 4, wherein upon detection of a failure of an LED (22, 21) of one of its own luminous surfaces or of the common luminous surface, the first (54) and the first further output (51) are switched off, and upon detection of a failure of an LED (23, 21) of the other of its own luminous surfaces or of the common luminous surface, the second as well as the second and the third further output are switched off. Illuminant according to one of the preceding claims, wherein it comprises an on-board power supply connection. Illuminant according to one of the preceding claims, wherein the LED driver arrangement (03) comprises a plurality of single-channel LED drivers. Illuminant according to one of the preceding claims, wherein the LED driver arrangement (03) comprises one or more multi-channel LED drivers. Illuminant according to one of the preceding claims with a double number of outputs (05) for the LEDs (02) or LED strings assigned to the separate luminous surfaces and the common luminous surface, wherein the LEDs (02, 21, 22, 23) of the luminous surfaces are connected to respective double outputs (57) in addition to the first output (54), the second output (55) and the three further outputs (51, 52, 53) comprising simple outputs (56) to which they are already connected, each of which outputs its own current intensity as the respective simple outputs in order to operate the lighting functions with different brightness levels. Illuminant according to claim 9, wherein it has at least one brightness level control signal input (06). Illuminant according to one of the preceding claims, wherein the LED driver arrangement (03) comprises one or more linear LED drivers. Illuminant according to one of the preceding claims, wherein the LED driver arrangement (03) comprises one or more PWM generators (PWM: pulse width modulation). Illuminant according to claim 12, wherein the PWM generator is operated in push-pull mode at the low-current outputs (51, 52, 53, 54, 56) which add up to a high current intensity. Vehicle lamp with a lamp interior at least partially enclosed by a lamp housing with at least one light opening and a light disk closing it, and at least one illuminant (01) accommodated therein and comprising several LEDs (02, 21, 22, 23) as light sources for at least two light functions of the vehicle lamp realized by means of luminous surfaces overlapping one another in at least one common luminous surface (bi-function luminous surface), comprising a luminous means (01) according to one of the preceding claims. A vehicle lamp according to claim 14, wherein it is designed as a rear lamp for a motor vehicle.

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